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This page provides supplementary chemical data on tetrahydrofuran .
The handling of this chemical may incur notable safety precautions. It is highly recommend that you seek the Material Safety Datasheet ( MSDS ) for this chemical from a reliable source such as SIRI , and follow its directions. MSDS is available at Mallinckrodt Baker .
123.9 J/(mol K) at 25°C
Vapor pressure 143 mm Hg at 20°C [ 1 ] | https://en.wikipedia.org/wiki/Tetrahydrofuran_(data_page) |
In chemistry , tetrahydroxozincate or tetrahydroxidozincate [ 1 ] is a divalent anion (negative ion ) with formula Zn(OH) 2− 4 , with a central zinc atom in the +2 or (II) valence state coordinated to four hydroxide groups. It has Sp3 hybridization. It is the most common of the zincate anions, and is often called just zincate .
These names are also used for the salts containing that anion, such as sodium zincate Na 2 Zn(OH) 4 [ 2 ] and calcium zincate CaZn(OH) 4 ·2H 2 O [ 3 ]
Zincate salts can be obtained by reaction of zinc oxide (ZnO) or zinc hydroxide ( Zn(OH) 2 ) and a strong base like sodium hydroxide .
It is now generally accepted that the resulting solutions contain the tetrahydroxozincate ion. [ 4 ] Earlier Raman studies had been interpreted as indicating the existence of linear ZnO 2− 2 ions. [ 5 ]
The name "zincate" may also refer to a polymeric anion with formula approaching [ Zn(OH) − 3 ] n , which forms salts such as NaZn(OH) 3 · H 2 O , [ 6 ] or to mixed oxides of zinc and less electronegative elements, such as Na 2 ZnO 2 . [ 7 ] | https://en.wikipedia.org/wiki/Tetrahydroxozincate |
Tetrahymena is a genus of free-living ciliates , examples of unicellular eukaryotes . [ 1 ] The genus Tetrahymena is the most widely studied member of its phylum . [ 2 ] : 59 It can produce, store and react with different types of hormones. Tetrahymena cells can recognize both related and hostile cells. [ 3 ]
They can also switch from commensalistic to pathogenic modes of survival. [ citation needed ] They are common in freshwater lakes, ponds, and streams. [ 2 ] : 277
Tetrahymena species used as model organisms in biomedical research are T. thermophila and T. pyriformis . [ 4 ] [ page needed ]
As a ciliated protozoan , Tetrahymena thermophila exhibits nuclear dimorphism : two types of cell nuclei . They have a bigger, non-germline macronucleus and a small, germline micronucleus in each cell at the same time and these two carry out different functions with distinct cytological and biological properties. This unique versatility allows scientists to use Tetrahymena to identify several key factors regarding gene expression and genome integrity. In addition, Tetrahymena possess hundreds of cilia and has complicated microtubule structures, making it an optimal model to illustrate the diversity and functions of microtubule arrays.
Because Tetrahymena can be grown in a large quantity in the laboratory with ease, it has been a great source for biochemical analysis for years, specifically for enzymatic activities and purification of sub-cellular components . In addition, with the advancement of genetic techniques it has become an excellent model to study the gene function in vivo . The recent sequencing of the macronucleus genome should ensure that Tetrahymena will be continuously used as a model system.
Tetrahymena thermophila exists in seven different sexes ( mating types ) that can reproduce in 21 different combinations, and a single tetrahymena cannot reproduce sexually with itself. Each organism "decides" which sex it will become during mating, through a stochastic process. [ 5 ] [ 6 ]
Studies on Tetrahymena have contributed to several scientific milestones including:
The life cycle of T. thermophila consists of an alternation between asexual and sexual stages. In nutrient rich media during vegetative growth cells reproduce asexually by binary fission . This type of cell division occurs by a sequence of morphogenetic events that results in the development of duplicate sets of cell structures, one for each daughter cell. Only during starvation conditions will cells commit to sexual conjugation , pairing and fusing with a cell of opposite mating type. Tetrahymena has seven mating types; each of which can mate with any of the other six without preference, but not its own.
Typical of ciliates, T. thermophila differentiates its genome into two functionally distinct types of nuclei, each specifically used during the two different stages of the life cycle. The diploid germline micronucleus is transcriptionally silent and only plays a role during sexual life stages. The germline nucleus contains 5 pairs of chromosomes which encode the heritable information passed down from one sexual generation to the next. During sexual conjugation, haploid micronuclear meiotic products from both parental cells fuse, leading to the creation of a new micro- and macronucleus in progeny cells. Sexual conjugation occurs when cells starved for at least 2hrs in a nutrient-depleted media encounter a cell of complementary mating type. After a brief period of co-stimulation (~1hr), starved cells begin to pair at their anterior ends to form a specialized region of membrane called the conjugation junction.
It is at this junctional zone that several hundred fusion pores form, allowing for the mutual exchange of protein, RNA and eventually a meiotic product of their micronucleus. This whole process takes about 12 hours at 30 °C, but even longer than this at cooler temperatures. The sequence of events during conjugation is outlined in the accompanying figure. [ 10 ]
The larger polyploid macronucleus is transcriptionally active, meaning its genes are actively expressed, and so it controls somatic cell functions during vegetative growth. The polyploid nature of the macronucleus refers to the fact that it contains approximately 200–300 autonomously replicating linear DNA mini-chromosomes. These minichromosomes have their own telomeres and are derived via site-specific fragmentation of the five original micronuclear chromosomes during sexual development. In T. thermophila each of these minichromosomes encodes multiple genes and exists at a copy number of approximately 45-50 within the macronucleus. The exception to this is the minichromosome encoding the rDNA, which is massively upregulated, existing at a copy number of approximately 10,000 within the macronucleus. Because the macronucleus divides amitotically during binary fission, these minichromosomes are un-equally divided between the clonal daughter cells. Through natural or artificial selection, this method of DNA partitioning in the somatic genome can lead to clonal cell lines with different macronuclear phenotypes fixed for a particular trait, in a process called phenotypic assortment. In this way, the polyploid genome can fine-tune its adaptation to environmental conditions through gain of beneficial mutations on any given mini-chromosome whose replication is then selected for, or conversely, loss of a minichromosome which accrues a negative mutation. However, the macronucleus is only propagated from one cell to the next during the asexual, vegetative stage of the life cycle, and so it is never directly inherited by sexual progeny. Only beneficial mutations that occur in the germline micronucleus of T. thermophila are passed down between generations, but these mutations would never be selected for environmentally in the parental cells because they are not expressed. [ 11 ]
Free swimming cells of Tetrahymena are attracted to certain chemicals by chemokinesis . The major chemo-attractants are peptides and/or proteins. [ 12 ]
A 2016 study found that cultured Tetrahymena have the capacity to 'learn' the shape and size of their swimming space. Cells confined in a droplet of a water for a short time were, upon release, found to repeat the circular swimming trajectories 'learned' in the droplet. The diameter and duration of these swimming paths reflected the size of the droplet and time allowed to adapt. [ 13 ]
It is common among protists that the sexual cycle is inducible by stressful conditions such as starvation. [ 14 ] Such conditions often cause DNA damage. A central feature of meiosis is homologous recombination between non-sister chromosomes. In T. thermophila this process of meiotic recombination may be beneficial for repairing DNA damages caused by starvation.
Exposure of T. thermophila to UV light resulted in a greater than 100-fold increase in Rad51 gene expression. [ 15 ] Treatment with the DNA alkylating agent methyl methanesulfonate also resulted in substantially elevated Rad 51 protein levels. These findings suggest that ciliates such as T. thermophila utilize a Rad51-dependent recombinational pathway to repair damaged DNA.
The Rad51 recombinase of T. thermophila is a homolog of the Escherichia coli RecA recombinase. In T. thermophila , Rad51 participates in homologous recombination during mitosis , meiosis and in the repair of double-strand breaks. [ 16 ] During conjugation, Rad51 is necessary for completion of meiosis. Meiosis in T. thermophila appears to employ a Mus81-dependent pathway that does not use a synaptonemal complex and is considered secondary in most other model eukaryotes . [ 17 ] This pathway includes the Mus81 resolvase and the Sgs1 helicase. The Sgs1 helicase appears to promote the non-crossover outcome of meiotic recombinational repair of DNA, [ 18 ] a pathway that generates little genetic variation.
Many species of Tetrahymena are known to display unique response mechanisms to stress and various environmental pressures. The unique genomic architecture of the ciliates (presence of a MIC, high ploidy, large number of chromosomes, etc.) allows for differential gene expression, as well as increased genomic flexibility. The following is a non-exhaustive list of examples of phenotypic and genotypic plasticity in the Tetrahymena genus.
T. vorax is known for its inducible trophic polymorphisms, an ecologically offensive tactic that allows it to change its feeding strategy and diet by altering its morphology. [ 19 ] Normally, T. vorax is a bacterivorous microstome around 60 μm in length. However, it has the ability to switch into a carnivorous macrostome around 200 μm in length that can feed on larger competitors. If T. vorax cells are too nutrient starved to undertake transformation, they have also been recorded as transforming into a third "tailed"-microstome morph, thought to be a defense mechanism in response to cannibalistic pressure. While T. vorax is the most well studied Tetrahymena that exhibits inducible trophic polymorphisms, many lesser known species are able to undertake transformation as well, including T. paulina and T. paravorax . [ 20 ] However, only T. vorax has been recorded as having both a macrostome and tailed-microstome form.
These morphological switches are triggered by an abundance of stomatin in the environment, a mixture of metabolic compounds released by competitor species, such as Paramecium , Colpidium , and other Tetrahymena . Specifically, chromatographic analysis has revealed that ferrous iron, hypoxanthine , and uracil are the chemicals in stomatin responsible for triggering the morphological change. [ 21 ] Many researchers cite "starvation conditions" as inducing the transformation, as in nature, the compound inducers are in highest concentration after microstomal ciliates have grazed down bacterial populations, and ciliate populations are high. When the chemical inducers are in high concentration, T. vorax cells will transform at higher rates, allowing them to prey on their former trophic competitors.
The exact genetic, and structural mechanisms that underlie T. vorax transformation are unknown. However, some progress has been made in identifying candidate genes. Researchers from the University of Alabama have used cDNA subtraction to remove actively transcribed DNA from microstome and macrostome T. vorax cells, leaving only differentially transcribed cDNA molecules. [ 22 ] While nine differentiation-specific genes were found, the most frequently expressed candidate gene was identified as a novel sequence, SUBII-TG .
The sequenced region of SUBII-TG was 912 bp long and consists of three largely identical 105 bp open-reading frames. A northern blot analysis revealed that low levels of transcription are detected in microstome cells, while high levels of transcription occur in macrostome cells. Furthermore, when the researchers limited SUBII-TG expression in the presence of stomatin (using antisense oligonucleotide methods), a 55% reduction in SUBII-TG mRNA correlated with a 51% decrease in transformation, supporting the notion that the gene is at least partially responsible for controlling the transformation in T. vorax . However, very little is known about the SUBII-TG gene. Researchers were only able to sequence a portion of the entire open-reading frame, and other candidate genes have not been investigated thoroughly. mRNA and amino acid sequencing indicate that ubiquitin may play a crucial role in allowing transformation to take place as well. However, no known genes in the ubiquitin family have been identified in T. vorax . [ 23 ] Finally, the genetic mechanisms of the "tailed" microstome morph are completely unknown.
Other related species exhibit their own unique responses to various stressors. In T. thermophila , chromosome amplification and gene expansion are inducible responses to common organometallic pollutants such as cadmium, copper, and lead. [ 24 ] Strains of T. thermophila that were exposed to large quantities of Cd 2+ over time were found to have a 5-fold increase of MTT1 , and MTT3 (metallothionein genes that code for Cadmium and Lead binding proteins) as well as CNBDP , an unrelated gene that lies just upstream of MTT1 on the same chromosome. The fact that a non-metallothionein gene on the same locus as MTT1 and MTT3 increased copy number indicates that the entire chromosome had been amplified, as opposed to just specific genes. Tetrahymena species are 45-ploid for their macronucleus, meaning that the wild type of T. thermophila normally contains 45 copies of each chromosome. While the actual number of unique chromosomes are unknown, the number is thought to be around 187 in the MAC, and 5 in the MIC. [ 25 ] Thus, the Ca 2+ adapted strain contained 225 copies of the specific chromosome in question. This resulted in a nearly 28-fold increase in detected expression levels of MTT1 , and slightly less in MTT3 .
When researchers grew a sample of the T. thermophila population in normal growth medium (lacking Cd 2+ ) for one month, the number of MTT1 , MTT3 , and CNBDP genes decreased to an average of three copies (135C). By seven months in normal growth medium, the T. thermophila cells were found reduced to just the wild type copy number (45C). When researchers returned cells from the same colony to Cd 2+ medium, within a week MTT1 , MTT3 , and CNBDP genes increased to three copies once again (135C). Thus, the authors argue that chromosome amplification is an inducible and reversible mechanism in the Tetrahymena genetic response to metal stress.
Researchers also used gene-knockdown experiments, where the copy number of another metallothionein gene on a different chromosome, MTT5 , was dramatically reduced. Within a week, the new strain was found to have developed four novel genes from at least one duplication of MTT1 . However, chromosome duplication had not taken place, as indicated by the wild-type ploidy and the normal quantity of other genes on the same chromosomes. Rather, researchers believe that the duplication resulted from homologous recombination events, producing transcriptionally active, upregulated genes that carry repeated MTT1 .
T. thermophila also undergoes phenotypic changes when faced with limited resource availability. Cells are capable of changing their shape and size, along with behavioral swimming strategies in response to starvation. [ 26 ] The more motile cells that change in response to starvation are known as dispersers, or disperser cells. While rates and levels of phenotypic change differ between strains, disperser cells form in nearly all strains of T. thermophila when faced with starvation. Dispersers, and non-dispersing cells both become dramatically thinner and smaller, increasing the basal body and cilia density, allowing them to swim between two and three times faster than normal cells. [ 27 ] Some strains of T. thermophila have also been found to develop a single, non-beating, enlarged cilia that assists the cell in steering or directing movement. While the behavior has been shown to correlate with faster dispersal and form as a reversible trait in Tetrahymena cells, little is known about the genetic or cellular mechanisms that allow for its development. Furthermore, other studies show that when genetically variable populations of T. thermophila were starved, dispersal cells actually increased in cell length, despite still becoming thinner. [ 28 ] More research is needed to determine the genetic mechanisms that underlie disperser formation.
Species in this genus include. [ 1 ]
Cornell University offers a National Institutes of Health (NIH) funded program through the Science Education Partnership Award (SEPA) Program called Advancing Secondary Science Education thru Tetrahymena (ASSET). [ 29 ] The group develops stand-alone labs or lessons using Tetrahymena as training modules that teachers can use in classes. | https://en.wikipedia.org/wiki/Tetrahymena |
Tetrakis(pyridine)silver(II) peroxydisulfate is a chemical compound which contains silver in the rare oxidation state of +2.
The salt can be easily prepared by oxidizing a soluble silver salt with excess potassium peroxydisulfate in aqueous pyridine solution, where upon the product precipitates out almost quantitatively. [ 1 ]
Since the Ag 2+ ion has a d 9 configuration, the salt is paramagnetic. [ 1 ]
The compound is in the form of non-hygroscopic orange granulate. It is stable in the air for several days when stored away from light, and is stable up to several months if dried in vacuo over potassium hydroxide , decomposing into a white paste. Its stability can be attributed to its insolubility in both polar and non-polar solvents.
The compound decomposes at 137 °C. It dissolves in concentrated nitric acid without reduction, and is converted to the black silver(I,III) oxide in aqueous sodium hydroxide solution. [ 1 ]
It is a powerful oxidizing agent, and is illustrated by the fact that it oxidizes Mn 2+ ions to permanganates . When the pyridine ligands were removed, the transient square planar [Ag(H 2 O) 4 ] 2+ remains, which spontaneously oxidizes water to oxygen . [ 2 ]
The complex ion can easily oxidize alcohol , aldehyde and amine , and capable of decarboxylating α-hydroxycarboxylic acids and phenylacetic acids to give the corresponding carbonyl compounds. [ 3 ] Benzylic C-H bonds are oxidatively converted to carbonyl groups: [ 3 ]
Aromatic thiols and allylaryl thioethers are oxidized to aryl sulfonic acids , which gives an alternative route to produce arylsulfonic acids with mild conditions. [ 3 ]
As the compound contains the peroxydisulfate ion as the counter anion, this compound should be treated as an explosive even though its explosive properties were not well established. The complex also releases tiny amounts of pyridine vapor which is a possible carcinogen. | https://en.wikipedia.org/wiki/Tetrakis(pyridine)silver(II)_peroxydisulfate |
Tetrakis(triphenylphosphine)platinum(0) Tetrakis(triphenylphosphine)nickel(0)
Tetrakis(triphenylphosphine)palladium(0) (sometimes called quatrotriphenylphosphine palladium) is the chemical compound [Pd(P(C 6 H 5 ) 3 ) 4 ], often abbreviated Pd ( PPh 3 ) 4 , or rarely PdP 4 . It is a bright yellow crystalline solid that becomes brown upon decomposition in air .
The four phosphorus atoms are at the corners of a tetrahedron surrounding the palladium(0) center. This structure is typical for four-coordinate 18 e − complexes. [ 2 ] The corresponding complexes Ni(PPh 3 ) 4 and Pt(PPh 3 ) 4 are also well known. Such complexes reversibly dissociate PPh 3 ligands in solution, so reactions attributed to Pd(PPh 3 ) 4 often in fact arise from Pd(PPh 3 ) 3 or even Pd(PPh 3 ) 2 . [ 3 ]
Tetrakis(triphenylphosphine)palladium(0) was first prepared by Lamberto Malatesta et al. in the 1950s by reduction of sodium chloropalladate with hydrazine in the presence of the phosphine . [ 4 ] It is commercially available, but can be prepared in two steps from Pd(II) precursors:
Both steps may be carried out in a one-pot reaction , without isolating and purifying the PdCl 2 (PPh 3 ) 2 intermediate. [ 5 ] Reductants other than hydrazine can be employed, including ascorbic acid . [ 6 ] The compound is sensitive to air, but can be purified by washing with methanol to give the desired yellow powder. It is usually stored cold under argon .
Pd(PPh 3 ) 4 is widely used as a catalyst for palladium-catalyzed coupling reactions . [ 7 ] Prominent applications include the Heck reaction , Suzuki coupling , Stille coupling , Sonogashira coupling , and Negishi coupling . These processes begin with two successive ligand dissociations followed by the oxidative addition of an aryl halide to the Pd(0) center: | https://en.wikipedia.org/wiki/Tetrakis(triphenylphosphine)palladium(0) |
The tetralemma is a figure that features prominently in the logic of India .
It states that with reference to any a logical proposition (or axiom) X, there are four possibilities:
The history of fourfold negation, the Catuskoti (Sanskrit), is evident in the logico-epistemological tradition of India, given the categorical nomenclature Indian logic in Western discourse. Subsumed within the auspice of Indian logic, ' Buddhist logic ' has been particularly focused in its employment of the fourfold negation, as evidenced by the traditions of Nagarjuna and the Madhyamaka , particularly the school of Madhyamaka given the retroactive nomenclature of Prasangika by the Tibetan Buddhist logico-epistemological tradition. Though tetralemma was also used as a form inquiry rather than logic in the Nasadiya Sukta of Rigveda (creation hymn) though seems to be rarely used as a tool of logic before Buddhism. [ 1 ] | https://en.wikipedia.org/wiki/Tetralemma |
A tetramer assay (also known as a tetramer stain ) is a procedure that uses tetrameric proteins to detect and quantify T cells that are specific for a given antigen within a blood sample. [ 1 ] The tetramers used in the assay are made up of four major histocompatibility complex (MHC) molecules, which are found on the surface of most cells in the body. [ 2 ] MHC molecules present peptides to T-cells as a way to communicate the presence of viruses, bacteria, cancerous mutations, or other antigens in a cell. If a T-cell's receptor matches the peptide being presented by an MHC molecule, an immune response is triggered. [ 3 ] Thus, MHC tetramers that are bioengineered to present a specific peptide can be used to find T-cells with receptors that match that peptide.
The tetramers are labeled with a fluorophore , allowing tetramer-bound T-cells to be analyzed with flow cytometry . [ 4 ] Quantification and sorting of T-cells by flow cytometry enables researchers to investigate immune response to viral infection and vaccine administration as well as functionality of antigen-specific T-cells. [ 5 ] Generally, if a person's immune system has encountered a pathogen , the individual will possess T cells with specificity toward some peptide on that pathogen. Hence, if a tetramer stain specific for a pathogenic peptide results in a positive signal, this may indicate that the person's immune system has encountered and built a response to that pathogen. [ citation needed ]
This methodology was first published in 1996 by a lab at Stanford University. [ 6 ] Previous attempts to quantify antigen-specific T-cells involved the less accurate limiting dilution assay, which estimates numbers of T-cells at 50-500 times below their actual levels. [ 7 ] [ 8 ] Stains using soluble MHC monomers were also unsuccessful due to the low binding affinity of T-cell receptors and MHC-peptide monomers. MHC tetramers can bind to more than one receptor on the target T-cell, resulting in an increased total binding strength and lower dissociation rates. [ 5 ]
Tetramer stains usually analyze cytotoxic T lymphocyte (CTL) populations. [ 9 ] CTLs are also called CD8+ T-cells, because they have CD8 co-receptors that bind to MHC class I molecules. Most cells in the body express MHC class I molecules, which are responsible for processing intracellular antigens and presenting at the cell's surface. If the peptides being presented by MHC class I molecules are foreign—for example, derived from viral proteins instead of the cell's own proteins—the CTL with a receptor that matches the peptide will destroy the cell. [ 2 ] [ 3 ] Tetramer stains allow for the visualization, quantification, and sorting of these cells by flow cytometry, which is extremely useful in immunology . T-cell populations can be tracked over the duration of a virus or after the application of a vaccine. Tetramer stains can also be paired with functional assays like ELIspot , which detects the number of cytokine secreting cells in a sample. [ 9 ]
MHC tetramer molecules developed in a lab can mimic the antigen presenting complex on cells and bind to T-cells that recognize the antigen. Class I MHC molecules are made up of a polymorphic heavy α-chain associated with an invariant light chain beta-2 microglobulin (β2m). Escherichia coli are used to synthesize the light chain and a shortened version of the heavy chain that includes the biotin 15 amino acid recognition tag. These MHC chains are biotinylated with the enzyme BirA and refolded with the antigenic peptide of interest. Biotin is a small molecule that forms a strong bond with another protein called streptavidin. Fluorophore tagged streptavidin is added to the bioengineered MHC monomers, and the biotin-streptavidin interaction causes four MHC monomers to bind to the streptavidin and create a tetramer. When the tetramers are mixed with a blood sample, they will bind to T-cells expressing the appropriate antigen specific receptor. Any MHC tetramers that are not bound are washed out of the sample before it is analyzed with flow cytometry. [ 9 ]
Recent advancements within recombinant MHC molecules have democratised peptide MHC complex formulation and subsequent multimerisation. Highly active formulations of a broad range of MHC class I molecules [ 10 ] now allows non-experts users to make their own custom peptide-MHC complexes from day-to-day in any lab without special equipment. [ citation needed ]
Tetramers that bind to helper T-cells have also been developed. [ 9 ] Helper T-cells or CD4+ T-cells express CD4 co-receptors. They bind to class II MHC molecules, which are only expressed in professional antigen-presenting cells like dendritic cells or macrophages . Class II MHC molecules present extracellular antigens, allowing helper T-cells to detect bacteria, [ 11 ] fungi, and parasites. [ 2 ] Class II MHC tetramer use is becoming more common, but the tetramers are more difficult to create than class I tetramers and the bond between helper T-cells and MHC molecules is even weaker. [ 9 ] [ 12 ]
Natural killer T-cells (NKT cells) can also be visualized with tetramer technology. NKT cells bind to proteins that present lipid or glycolipid antigens. [ 13 ] The antigen presenting complex that NKT cells bind to involves CD1 proteins, so tetramers made of CD1 can be used to stain for NKT cells. [ 9 ]
An early application of tetramer technology focused on the cell-mediated immune response to HIV infection. MHC tetramers were developed to present HIV antigens and used to find the percentage of CTLs specific to those HIV antigens in blood samples of infected patients. This was compared to results of cytotoxic assays and plasma RNA viral load to characterize the function of CTLs in HIV infection. The CTLs that bound to tetramers were sorted into ELIspot wells for analysis of cytokine secretion. [ 14 ]
Another study utilized MHC tetramer complexes to investigate the effectiveness of an influenza vaccine delivery method. Mice were given subcutaneous and intranasal vaccinations for influenza, and tetramer stains coupled with flow cytometry were used to quantify the CTLs specific to the antigen used in the vaccine. This allowed for comparison of the immune response (the number of T-cells that target a virus) in two different vaccine delivery methods. [ 15 ] | https://en.wikipedia.org/wiki/Tetramer_assay |
A tetrameric protein is a protein with a quaternary structure of four subunits (tetrameric). Homotetramers have four identical subunits (such as glutathione S-transferase ), and heterotetramers are complexes of different subunits. A tetramer can be assembled as dimer of dimers with two homodimer subunits (such as sorbitol dehydrogenase ), or two heterodimer subunits (such as hemoglobin ).
The interactions between subunits forming a tetramer is primarily determined by non covalent interaction. [ 1 ] Hydrophobic effects , hydrogen bonds and electrostatic interactions are the primary sources for this binding process between subunits. For homotetrameric proteins such as sorbitol dehydrogenase (SDH), the structure is believed to have evolved going from a monomeric to a dimeric and finally a tetrameric structure in evolution. The binding process in SDH and many other tetrameric enzymes can be described by the gain in free energy which can be determined from the rate of association and dissociation. [ 1 ] The above image shows the assembly of the four subunits (A,B,C and D) in SDH.
Hydrogen bonding networks between subunits has been shown to be important for the stability of the tetrameric quaternary protein structure . For example, a study of SDH which used diverse methods such as protein sequence alignments , structural comparisons, energy calculations, gel filtration experiments and enzyme kinetics experiments, could reveal an important hydrogen bonding network which stabilizes the tetrameric quaternary structure in mammalian SDH. [ 1 ]
In immunology , MHC tetramers can be used in tetramer assays , to quantify numbers of antigen-specific T cells (especially CD8+ T cells ). MHC tetramers are based on recombinant class I molecules that, through the action of bacterial BirA, have been biotinylated . These molecules are folded with the peptide of interest and β2M and tetramerized by a fluorescently labeled streptavidin . (Streptavidin binds to four biotins per molecule.) This tetramer reagent will specifically label T cells that express T cell receptors that are specific for a given peptide-MHC complex. For example, a Kb/FAPGNYPAL tetramer will specifically bind to Sendai virus specific cytotoxic T cell in a C57BL/6 mouse. Antigen specific responses can be measured as CD8+, tetramer+ T cells as a fraction of all CD8+ lymphocytes.
The reason for using a tetramer, as opposed to a single labeled MHC class I molecule is that the tetrahedral tetramers can bind to three TCRs at once, allowing specific binding in spite of the low (1 micromolar) affinity of the typical class I-peptide-TCR interaction. MHC class II tetramers can also be made, although these are more difficult to work with practically. [ 2 ]
A homotetramer is a protein complex made up of four identical subunits which are associated but not covalently bound. [ 3 ] Conversely, a heterotetramer is a 4-subunit complex where one or more subunits differ. [ 4 ]
Examples of homotetramers include:
Examples of heterotetramers include haemoglobin ( pictured ), the NMDA receptor , some aquaporins , [ 7 ] some AMPA receptors , as well as some enzymes . [ 8 ]
Ion-exchange chromatography is useful for isolating specific heterotetrameric protein assemblies, allowing purification of specific complexes according to both the number and the position of charged peptide tags. [ 9 ] [ 10 ] Nickel affinity chromatography may also be employed for heterotetramer purification. [ 11 ]
Multiple copies of a polypeptide encoded by a gene often can form an aggregate referred to as a multimer. When a multimer is formed from polypeptides produced by two different mutant alleles of a particular gene, the mixed multimer may exhibit greater functional activity than the unmixed multimers formed by each of the mutants alone. When a mixed multimer displays increased functionality relative to the unmixed multimers, the phenomenon is referred to as intragenic complementation . In humans, argininosuccinate lyase (ASL) is a homotetrameric enzyme that can undergo intragenic complementation. An ASL disorder in humans can arise from mutations in the ASL gene, particularly mutations that affect the active site of the tetrameric enzyme. ASL disorder is associated with considerable clinical and genetic heterogeneity which is considered to reflect the extensive intragenic complementation occurring among different individual patients. [ 12 ] [ 13 ] [ 14 ] | https://en.wikipedia.org/wiki/Tetrameric_protein |
Tetramethyl bisphenol F ( TMBPF ) is a new coating intended as a safer replacement [ 1 ] for bisphenol A and bisphenol F to use in epoxy linings of aluminium cans and steel cans . It was previously suggested as an insulator in electronic circuit boards. [ 2 ]
Polymerization of tetramethyl bisphenol F occurs with epichlorohydrin when heated between 40 and 70 °C using an alkali as a catalyst to form the resin used as a coating. [ 3 ]
Causes serious eye irritation. May cause respiratory and skin irritation. Very toxic to aquatic life. [ 4 ]
TMBPF does not have any effect on the endocrine system; it does not leach out of cans because unlike BPA it is fully polymerized when deposited on the metal, so there is no free chemical to leach out. [ 2 ] Tetramethyl bisphenol F was tested on rats to see if there were effects like male or female hormones. It had almost no effects like this. [ 5 ] However, a different study did find effects. [ 6 ] | https://en.wikipedia.org/wiki/Tetramethyl_bisphenol_F |
Tetramethylammonium fluoride , commonly abbreviated TMAF , is the quaternary ammonium salt with the formula (CH 3 ) 4 NF. This hygroscopic white solid is a source of “naked fluoride": fluoride ions not complexed with a metal atom. Most other soluble salts of fluoride are in fact bifluorides , HF 2 – . Historically, there have been two main approaches to prepare tetramethylammonium fluoride: hydrofluoric acid neutralization of tetramethylammonium hydroxide , and salt metathesis between different ammonium salts and inorganic fluoride sources, such as KF or CsF . [ 1 ] Because the fluoride anion is extremely basic , the salt slowly reacts with acetonitrile , inducing dimerization to CH 3 C(NH 2 )=CHCN, which co-crystallizes. [ 2 ] | https://en.wikipedia.org/wiki/Tetramethylammonium_fluoride |
Tetramethylazodicarboxamide (also known as TMAD and diamide ) is a reagent used in biochemistry for oxidation of thiols in proteins to disulfides . [ 2 ] It has also been used as a reagent in the Mitsunobu reaction in place of diethyl azodicarboxylate . [ 1 ]
This article about an organic compound is a stub . You can help Wikipedia by expanding it . | https://en.wikipedia.org/wiki/Tetramethylazodicarboxamide |
This page provides supplementary chemical data on tetramethylethylenediamine .
The handling of this chemical may incur notable safety precautions. It is highly recommend that you seek the Material Safety Datasheet ( MSDS ) for this chemical from a reliable source such as SIRI , and follow its directions. | https://en.wikipedia.org/wiki/Tetramethylethylenediamine_(data_page) |
Tetramethylphenylenediamine (TMPD) is an organic compound with the formula C 6 H 4 (N(CH 3 ) 2 ) 2 . It is most studied of three isomers of this formula. It is a colorless solid. With two dimethylamino substituents, the ring is particularly electron rich .
One-electron oxidation of TMPD gives the deep blue radical cation called Wurster's blue , C 6 H 4 (N(CH 3 ) 2 ) + 2 . It was one of the first radical cations to be reported. Many properties have been described including its rapid rate of self-exchange : [ 1 ]
X-ray crystallography of the TMPD and its iodide salt reveals that oxidation most strongly contracts the C-N(CH 3 ) 2 and the HC---CH bonds, indicating that oxidation gives a quinoid-like species. [ 2 ]
The monocation illustrates an early step in the oxidation of p-phenylenediamine derivatives, which are widely used for hair dying . [ 3 ] N,N-Dimethylphenylenediamine ( H 2 NC 6 H 4 N(CH 3 ) 2 ) also easily oxidizes to a radical cation, called Wurster's Red.
The hydrochloride salt of TMPD has been used as a redox indicator in the oxidase test and is also used in electron transport chain analysis as it is capable of donating electrons to cytochrome c . The midpoint potential for titration of the first electron is given as 0.276 V vs Standard hydrogen electrode , and this transition is useful in potentiometric titrations as both a redox mediator and indicator.
TMPD was reported in 1879 by Casmir Wurster (7 August 1854 – 29 November 1913), hence it is known as Wurster's reagent. [ 4 ] | https://en.wikipedia.org/wiki/Tetramethylphenylenediamine |
Tetranitratoxycarbon , systematic name tetra ( nitrato- O , O , O -methyl ) methane ( often shortened to tetrakis ( nitratoxycarbon ) methane ), [ 3 ] is a hypothetical molecule that was proposed by Clara Lazen, a fifth-grader in Kansas City, Missouri , who conceived of its structure and built a model in 2012. She is credited as co-author of a scientific paper on the molecule, which uses computational chemistry to predict that the molecule could actually exist.
Science teacher Kenneth Boehr was using ball-and-stick models to represent simple molecules during a fifth-grade class, when ten-year-old Clara Lazen [ 4 ] assembled a complex model and asked whether it was a real molecule. [ 5 ] It is unclear if Lazen randomly or deliberately assembled this particular molecule. [ 6 ]
Unsure if the molecule existed, Boehr sent a picture of the model to a chemist friend, Robert Zoellner at Humboldt State University . [ 4 ] [ 5 ] Zoellner checked the molecule against the Chemical Abstracts database [ 4 ] and confirmed that Lazen's model was of a structural type that had not been reported before. [ 5 ]
Zoellner wrote a paper on the molecule, published in Computational and Theoretical Chemistry , crediting Lazen and Boehr as co-authors. [ 3 ]
Tetranitratoxycarbon consists of oxygen , nitrogen , and carbon , with molecular structure C(CO 3 N) 4 . Its oxygen-rich formula, in particular, a positive oxygen balance , means it does not require any external oxidizer to undergo complete oxidation, and may thus have explosive or other high-energy properties. [ 3 ] However, it is expected to be too thermally unstable for practical use. [ 7 ]
The nitratoxycarbon functional group itself—a carbon atom and a nitrogen atom linked by three oxygen-atom bridges—has yet to be observed in any chemical compound. Computational chemistry studies indicate that it is only metastable , with other structural isomers such as the carboxylic nitroso - ester (C(=O)ONO) being more stable. [ 3 ] As such this functional group is likely to remain purely hypothetical and no method for its synthesis has yet been proposed. Compounds containing the general connective motif of two atoms connected by three one-atom linkers have been synthesized, including the all-carbon bicyclo[1.1.1]pentane and derivatives thereof, and several other elemental analogs have been mentioned in patents. | https://en.wikipedia.org/wiki/Tetranitratoxycarbon |
Tetranitromethane or TNM is an organic oxidizer with chemical formula C(NO 2 ) 4 . Its chemical structure consists of four nitro groups attached to one carbon atom. In 1857 it was first synthesised by the reaction of sodium cyanoacetamide with nitric acid . [ 4 ]
It has been investigated for use as an oxidizer in bipropellant rockets . Highly purified tetranitromethane cannot be made to explode, but its sensitivity is increased dramatically by oxidizable contaminants, such as anti-freezing additives. [ 5 ] The pure substance also has too high a freezing point to remain reliably molten, although the eutectic with dinitrogen tetroxide freezes at the much lower −30 °C and is less explosive than nearly-pure tetranitromethane. [ 6 ] Nevertheless, the oxidizer is still too sensitive for any effective use. [ 5 ] [ 6 ]
In the laboratory it is used as a reagent for the detection of double bonds in organic compounds and as a nitrating reagent. It has also found use as an additive to diesel fuel to increase the cetane number . [ 7 ]
TNM is a pale yellow liquid that can be prepared in the laboratory by the nitration of acetic anhydride with anhydrous nitric acid ( Chattaway 's method). [ 8 ] This method was attempted on an industrial scale in the 1950s by Nitroform Products Company in Newark, USA, but the entire plant was destroyed by an explosion in 1953. [ 9 ]
The first industrial scale production was started in Germany during World War II in an effort to improve the cetane number of diesel fuel. This process improved the original method, which started with acetic acid and nitric acid. [ 10 ] Without regard to yield or cost, approximately 10 tons of TNM were produced in a few weeks. However, this production process has not been used again industrially after the end of the war, because of high associated costs. [ 11 ]
For commercial use a cheaper method starting from acetylene has been used. [ 12 ] First, nitric acid containing mercuric nitrate is reduced by acetylene, resulting in trinitromethane (nitroform) and a mixture of carbon dioxide and nitrogen oxide as waste gas. The nitrogen oxides are valuable and normally recovered as nitric acid in an absorption tower. The resulting nitroform is converted to TNM by adding nitric and sulfuric acid at higher temperatures. With this method a yield of 90% (based on nitric acid) before purification can be reached. [ 13 ]
TNM is a prime example of molecular flexibility. It brought structural methods to the limits of their applicability as is shown by the fact that the structure of TNM was attempted to be determined for a period of more than 70 years in various phases. [ 14 ]
Early investigations by gas electron diffractions were unable to describe the observed diffraction pattern in full and only the application of a four-dimensional model concerning the correlated movement of the four NO 2 groups about the C–N bonds was able to describe the experimental observations fully. The problem occurs, because the two-fold local symmetry of the C−NO 2 units versus the three-fold symmetry of the C(NO 2 ) 3 unit, as well as the close proximity of the NO 2 groups hindering their free rotation, is the source for a very complicated mutually hindered movement of the NO 2 groups.
The crystal structure has also been attempted several times. A first decent solution of the problem required a model describing a highly disordered high‐temperature crystalline phase of a high-temperature phase (>174.4 K) as is shown in Figure 1. Reduction of symmetry and analysis of the twinning of the crystals led finally to a resolved disorder of the structure shown in Figure 2.
The structure of an ordered low‐temperature phase contains three independent molecules in the asymmetric unit. Structural parameters of the gaseous and solid phases are listed in the following table for comparison.
The ability of TNM to detonate is greatly affected by the presence of impurities, even in small quantities. TNM forms extremely powerful explosive mixtures when fuels are added in stoichiometric proportions. Many of these mixtures show sensitivity to impact even higher than that of nitroglycerine . [ 15 ]
Tetranitromethane can be used as a component of highly explosive liquid explosives as an oxidizing agent. It forms highly explosive mixtures with all flammable substances. When experimenting with this substance, paper filters should not be used for filtration. Even small impurities make tetranitromethane an explosive that explodes on impact or friction. A tragic lecture experiment at the University of Münster in 1920 is well known, where a small steel tube containing tetranitromethane, toluene and absorbent cotton detonated shortly before burning out in such a way that more than 30 students were injured, some seriously; [ 16 ] however, on the basis of the rector's office records, as many as 10 deaths and more than a dozen injuries are documented. [ 17 ] Thereupon the German Chemical-technical Reichsanstalt determined a detonation speed of 9300 meters per second. Alfred Stettbacher then proved comparatively that this mixture was far more explosive than hexogen , pentrite , blasting gelatine or panclastite and thus represented the most destructive explosive of all.
TNM reacts with moisture at elevated pH to produce trinitromethane (nitroform) which reacts easily with metals to form highly unstable and explosive salts. [ 18 ]
Tetranitromethane is highly toxic. Absorption of as little as 2.5 mg/kg can cause methemoglobinemia , pulmonary edema, and damage to liver, kidney, and central nervous system. It is reasonably expected to be a human carcinogen. [ 19 ] | https://en.wikipedia.org/wiki/Tetranitromethane |
The tetranortriterpenoid class of naturally occurring organic compounds, of which the most noted compound is azadirachtin , extracted from the neem tree ( Azadirachta indica ) that displays insecticidal properties. Azadirachtin mimics insect hormones called ecdysones that regulate the pupation of insects; application of azadirachtin interrupts the development and pupation of insects, eventually killing them.
The name indicates that the basic skeleton of such compounds contains 26 carbon atoms (4 fewer than triterpenes ).
Azadirachtin is a tetranortriterpenoid [ 1 ] and a limonoid .
This biochemistry article is a stub . You can help Wikipedia by expanding it . | https://en.wikipedia.org/wiki/Tetranortriterpenoid |
The tetranucleotide hypothesis of Phoebus Levene [ 1 ] proposed that DNA was composed of repeating sequences of four nucleotides. [ 2 ] It was very influential for three decades, and was developed by Levene at least into the 1910, and the diagram at the right illustrates the view of Levene and Tipson. [ 3 ] In 1940, at the time of Levene's death, Bass wrote in his obituary [ 4 ]
As a result of Levene’s work we have an exact concept of the structures of these huge molecules, probably the most complex biological materials whose architectural picture has been reconstructed.
In that form there is an implication that the four bases are present in equal amounts in DNA, and small variations in the experimental values were assumed to be the result of experimental error.
However, Erwin Chargaff [ 5 ] showed that the four frequencies were not equal, with variations consistent between different studies. Specifically, according to his rules the correct relationship is G = C ≠ A = T. The equalities G = C and A = T suggested that these bases were paired , this pairing being the basis of the DNA structure that is now known to be correct. Conversely the inequalities G ≠ A etc. meant that DNA could not have a systematic repetition of a fundamental unit, as required by the tetranucleotide hypothesis. Thus there was no reason why the sequence could not store information.
In later years some authorities considered the tetranucleotide hypothesis to have been harmful to the development of molecular biology. Bentley Glass , for example, called it a "scientific catastrophe". [ 6 ] More recently, Hargittai [ 7 ] saw it in a more positive light, and Frixione and Ruiz-Zamarripa [ 8 ] wrote as follows:
[Levene's] work was to culminate in Levene and Tipson’s 1935 report showing accurately for the first time the actual molecular structure of DNA, as well as a nearly correct depiction of the RNA structure. This achievement merits the distinction of this paper as a Classic in molecular biology literature. | https://en.wikipedia.org/wiki/Tetranucleotide_hypothesis |
Tetraoxidane is an inorganic compound of hydrogen and oxygen with the chemical formula H 2 O 4 . [ 1 ] [ 2 ] [ 3 ] This is one of the unstable hydrogen polyoxides . [ 4 ]
The compound is prepared by a chemical reaction between hydroperoxyl radicals ( HOO• ) at low temperatures: [ 5 ] [ 6 ]
This is the fourth member of the polyoxidanes. The first three are water [(mon)oxidane], hydrogen peroxide (dioxidane), and trioxidane . Tetraoxidane is more unstable than the previous compounds. The term "tetraoxidane" extends beyond the parent compound to several daughter compounds of the general formula R 2 O 4 , where R can be hydrogen, halogen atoms, or various inorganic and organic monovalent radicals. The two Rs together can be replaced by a divalent radical, so heterocyclic tetraoxidanes also exist. [ 7 ]
Tetraoxidane autoionizes when in liquid form: | https://en.wikipedia.org/wiki/Tetraoxidane |
The tetraploid complementation assay is a technique in biology in which cells of two mammalian embryos are combined to form a new embryo. [ 1 ] It is used to construct genetically modified organisms , to study the consequences of certain mutations on embryonal development, and in the study of pluripotent stem cells .
Normal mammalian somatic cells are diploid : each chromosome (and thus every gene ) is present in duplicate (excluding genes from X chromosome absent in Y chromosome). The assay starts with producing a tetraploid cell in which every chromosome exists fourfold. This is done by taking an embryo at the two-cell stage and fusing the two cells by applying an electrical current. The resulting tetraploid cell will continue to divide, and all daughter cells will also be tetraploid.
Such a tetraploid embryo can develop normally to the blastocyst stage and will implant in the wall of the uterus . The tetraploid cells can form the extra-embryonic tissue ( placenta , etc.); however, a proper fetus will rarely develop.
In the tetraploid complementation assay, one now combines such a tetraploid embryo (either at the morula or blastocyst stage) with normal diploid embryonic stem cells (ES) from a different organism. The embryo will then develop normally; the fetus is exclusively derived from the ES cell, while the extra-embryonic tissues are exclusively derived from the tetraploid cells. | https://en.wikipedia.org/wiki/Tetraploid_complementation_assay |
Tetrapropylammonium perruthenate ( TPAP or TPAPR ) is the chemical compound described by the formula N(C 3 H 7 ) 4 RuO 4 . Sometimes known as the Ley –Griffith reagent, this ruthenium compound is used as a reagent in organic synthesis . This salt consists of the tetrapropylammonium cation and the perruthenate anion, RuO − 4 .
Ruthenium tetroxide is a highly aggressive oxidant, but TPAP, which is its one-electron reduced derivative, is a mild oxidizing agent for the conversion of primary alcohols to aldehydes (the Ley oxidation ). [ 2 ] Secondary alcohols are similarly oxidized to ketones . [ 3 ] It can also be used to oxidize primary alcohols all the way to the carboxylic acid with a higher catalyst loading, larger amount of the cooxidant, and addition of two equivalents of water. In this situation, the aldehyde reacts with water to form the geminal diol hydrate , which is then oxidized again. [ 4 ]
The oxidation generates water that can be removed by adding molecular sieves . TPAP is expensive, but it can be used in catalytic amounts. The catalytic cycle is maintained by adding a stoichiometric amount of a co-oxidant such as N -methylmorpholine N -oxide [ 5 ] or molecular oxygen. [ 6 ]
TPAP is also used to cleave vicinal diols to form aldehydes. [ 3 ] | https://en.wikipedia.org/wiki/Tetrapropylammonium_perruthenate |
In particle physics , a tetraquark is an exotic meson composed of four valence quarks . A tetraquark state has long been suspected to be allowed by quantum chromodynamics , [ 1 ] the modern theory of strong interactions . A tetraquark state is an example of an exotic hadron that lies outside the conventional quark model classification. A number of different types of tetraquark have been observed. [ 2 ] [ 3 ]
Several tetraquark candidates have been reported by particle physics experiments in the 21st century. The quark contents of these states are almost all q q Q Q , where q represents a light ( up , down or strange ) quark, Q represents a heavy ( charm or bottom ) quark, and antiquarks are denoted with an overline. The existence and stability of tetraquark states with the qq Q Q (or q q QQ) have been discussed by theoretical physicists for a long time, however these are yet to be reported by experiments. [ 4 ]
In 2003, a particle temporarily called X(3872) , by the Belle experiment in Japan , was proposed to be a tetraquark candidate, [ 6 ] as originally theorized. [ 7 ] The name X is a temporary name, indicating that there are still some questions about its properties to be tested. The number following is the mass of the particle in MeV/ c 2 .
In 2004, the D sJ (2632) state seen in Fermilab 's SELEX was suggested as a possible tetraquark candidate. [ 8 ]
In 2007, Belle announced the observation of the Z(4430) state, a c c d u tetraquark candidate. There are also indications that the Y(4660) , also discovered by Belle in 2007, could be a tetraquark state. [ 9 ]
In 2009, Fermilab announced that they have discovered a particle temporarily called Y(4140) , which may also be a tetraquark. [ 10 ]
In 2010, two physicists from DESY and a physicist from Quaid-i-Azam University re-analyzed former experimental data and announced that, in connection with the ϒ (5S) meson (a form of bottomonium ), a well-defined tetraquark resonance exists. [ 11 ] [ 12 ]
In June 2013, the BES III experiment in China and the Belle experiment in Japan independently reported on Z c (3900) , the first confirmed four-quark state. [ 13 ]
In 2014, the Large Hadron Collider experiment LHCb confirmed the existence of the Z(4430) state with a significance of over 13.9 σ. [ 14 ] [ 15 ]
In February 2016, the DØ experiment reported evidence of a narrow tetraquark candidate, named X(5568), decaying to B 0 s π ± . [ 16 ] In December 2017, DØ also reported observing the X(5568) using a different B 0 s final state. [ 17 ] However, it was not observed in searches by the LHCb, [ 18 ] CMS , [ 19 ] CDF , [ 20 ] or ATLAS [ 21 ] experiments.
In June 2016, LHCb announced the discovery of three additional tetraquark candidates, called X(4274), X(4500) and X(4700). [ 22 ] [ 23 ] [ 24 ]
In 2020, LHCb announced the discovery of a c c c c tetraquark: X(6900). [ 2 ] [ 25 ] In 2022, ATLAS also observed X(6900), [ 26 ] and in 2023, CMS reported an observation of three such states, X(6600), X(6900), and X(7300). [ 27 ]
In 2021, LHCb announced the discovery of four additional tetraquarks, including c c u s . [ 3 ]
In 2022, LHCb announced the discovery of c s u d and c s u d. [ 28 ] | https://en.wikipedia.org/wiki/Tetraquark |
A tetrasaccharide is a carbohydrate which gives upon hydrolysis four molecules of the same or different monosaccharides . For example, stachyose upon hydrolysis gives one molecule each of glucose and fructose and two molecules of galactose . The general formula of a tetrasaccharide is typically C 24 H 42 O 21 .
This organic chemistry article is a stub . You can help Wikipedia by expanding it . | https://en.wikipedia.org/wiki/Tetrasaccharide |
Tetraselenium tetranitride is the inorganic compound with the formula Se 4 N 4 . Like the analogous tetrasulfur tetranitride S 4 N 4 , Se 4 N 4 is an orange solid. It is however less soluble and more shock-sensitive than S 4 N 4 . [ 2 ]
As determined by X-ray crystallography , Se 4 N 4 adopts a cage structure similar to that of S 4 N 4 . The Se−Se and Se−N distances are 2.740 and 1.800 Å , respectively. The N−Se−N angles are 90°. [ 1 ] [ 3 ]
Among its many reactions, [ 4 ] [ 5 ] Se 4 N 4 reacts with aluminium chloride to form adducts of Se 2 N 2 . [ 6 ] | https://en.wikipedia.org/wiki/Tetraselenium_tetranitride |
Tetraspanins are a family of membrane proteins found in all multicellular eukaryotes also referred to as the transmembrane 4 superfamily (TM4SF) proteins. These proteins have four transmembrane alpha-helices and two extracellular domains, one short (called the s mall e xtracellular d omain or l oop, SED/SEL or EC1) and one longer, typically 100 amino acid residues (the l arge e xtracellular d omain/ l oop, LED/LEL or EC2). Although several protein families have four transmembrane alpha-helices, tetraspanins are defined by conserved amino acid sequences including four or more cysteine residues in the EC2 domain, with two in a highly conserved 'CCG' motif. Tetraspanins are often thought to act as scaffolding proteins, anchoring multiple proteins to one area of the cell membrane. [ 1 ]
Tetraspanins are highly conserved between species. Some tetraspanins can have N -linked glycosylations on the long extracellular loop (LEL, EC2) and palmitoylations at a CXXC motif in their transmembrane region. [ 2 ]
There are 34 tetraspanins in mammals, 33 of which have also been identified in humans. Tetraspanins display numerous properties that indicate their physiological importance in cell adhesion, motility, activation, and proliferation , as well as their contribution to pathological conditions such as metastasis or viral infection.
A role for tetraspanins in platelets was demonstrated by the bleeding phenotypes of CD151- and TSSC6-deficient mice, which exhibit impaired "outside-in" signalling through α IIb β 3 , the major platelet integrin . It is hypothesized that tetraspanins interact with and regulate other platelet receptors. [ 3 ]
The schistosome worms make two tetraspanins: TSP-1 and TSP-2. TSP-2 antibodies are found in some people who seem to have immunity to schistosome infection ( Schistosomiasis ). [ 4 ] | https://en.wikipedia.org/wiki/Tetraspanin |
The tetrasporaphyte is a phase in the life history of algae which bear tetrasporangia . [ 1 ] This phase is usually morphologically similar to the gametophyte phase. [ 2 ]
This alga -related article is a stub . You can help Wikipedia by expanding it . | https://en.wikipedia.org/wiki/Tetrasporaphyte |
Tetraspores are red algae spores produced by the tetrasporophytic ( diploid ) phase in the life history of algae in the Rhodophyta as a result of meiosis . [ 1 ] The name is derived from the 4 spores that form after this meiosis , the division is of three kinds: cruciate , zonate and tetrahedral . [ 1 ]
This Rhodophyta -related article is a stub . You can help Wikipedia by expanding it . | https://en.wikipedia.org/wiki/Tetraspore |
Tetrasulfur tetranitride is an inorganic compound with the formula S 4 N 4 . This vivid orange, opaque, crystalline explosive is the most important binary sulfur nitride , which are compounds that contain only the elements sulfur and nitrogen . It is a precursor to many S-N compounds and has attracted wide interest for its unusual structure and bonding. [ 1 ] [ 2 ]
Nitrogen and sulfur have similar electronegativities . When the properties of atoms are so highly similar , they often form extensive families of covalently bonded structures and compounds. Indeed, a large number of S-N and S-NH compounds are known with S 4 N 4 as their parent.
S 4 N 4 adopts an unusual "extreme cradle" structure, with D 2d point group symmetry . It can be viewed as a derivative of a (hypothetical) eight-membered ring (or more simply a 'deformed' eight-membered ring) of alternating sulfur and nitrogen atoms. The pairs of sulfur atoms across the ring are separated by 2.586 Å , resulting in a cage-like structure as determined by single crystal X-ray diffraction. [ 3 ] The nature of the transannular S–S interactions remains a matter of investigation because it is significantly shorter than the sum of the van der Waals radii [ 4 ] but has been explained in the context of molecular orbital theory . [ 1 ] One pair of the transannular S atoms have valence 4, and the other pair of the transannular S atoms have valence 2. [ citation needed ] The bonding in S 4 N 4 is considered to be delocalized , which is indicated by the fact that the bond distances between neighboring sulfur and nitrogen atoms are nearly identical. S 4 N 4 has been shown to co-crystallize with benzene and the C 60 molecule. [ 5 ]
S 4 N 4 is stable to air . It is, however, unstable in the thermodynamic sense with a positive enthalpy of formation of +460 kJ/mol. This endothermic enthalpy of formation originates in the difference in energy of S 4 N 4 compared to its highly stable decomposition products:
S 4 N 4 is shock and friction sensitive and because one of its decomposition products is a gas, it is considered a primary explosive. [ 1 ] [ 6 ] Purer samples tend to be more sensitive. [ 7 ] Small samples can be detonated by striking with a hammer. S 4 N 4 is thermochromic , changing from pale yellow below −30 °C to orange at room temperature to deep red above 100 °C. [ 1 ]
S 4 N 4 was first prepared in 1835 by M. Gregory by the reaction of disulfur dichloride with ammonia , [ 8 ] a process that has been optimized: [ 9 ]
Coproducts of this reaction include heptasulfur imide ( S 7 NH ) and elemental sulfur, and the latter equilibrates with more S 4 N 4 and ammonium sulfide : [ 10 ]
A related synthesis employs [NH 4 ]Cl instead: [ 1 ]
An alternative synthesis entails the use of (((CH 3 ) 3 Si) 2 N) 2 S as a precursor with pre-formed S–N bonds. (((CH 3 ) 3 Si) 2 N) 2 S is prepared by the reaction of lithium bis(trimethylsilyl)amide and SCl 2 .
The (((CH 3 ) 3 Si) 2 N) 2 S reacts with the combination of SCl 2 and SO 2 Cl 2 to form S 4 N 4 , trimethylsilyl chloride , and sulfur dioxide : [ 11 ]
S 4 N 4 is a Lewis base at nitrogen. It binds to strong Lewis acids , such as SbCl 5 and SO 3 , or H[BF 4 ] :
The cage is distorted in these adducts . [ 1 ]
S 4 N 4 reacts with metal complexes, but the bonding situation may be quite complex. The cage remains intact in some cases but in other cases, it is degraded. [ 2 ] [ 12 ] For example, the soft Lewis acid CuCl forms a coordination polymer : [ 1 ]
Reportedly, [Pt 2 Cl 4 (P(CH 3 ) 2 Ph ) 2 ] initially forms a complex with S 4 N 4 at sulfur. This compound, upon standing, isomerizes to additionally bond through a nitrogen atom. S 4 N 4 oxidatively adds to Vaska's complex ( [Ir(Cl)(CO)(P Ph 3 ) 2 ] to form a hexacoordinate iridium complex where the S 4 N 4 binds through two sulfur atoms and one nitrogen atom. [ 2 ]
Dilute NaOH hydrolyzes S 4 N 4 as follows, yielding thiosulfate and trithionate : [ 1 ]
More concentrated base yields sulfite :
Many S-N compounds are prepared from S 4 N 4 . [ 13 ]
In electrophilic substitution or 1,3-dipolar cycloaddition reactions, S 4 N 4 behaves as a combination of the dithionitronium synthon and the sulfide synthon. Thus it adds to arenes and electron-rich alkynes to give 1,2,5‑ thiadiazoles . [ 14 ] Electron-poor alkynes attack S 4 N 4 to give a different cycloadduct of stoichiometry RC(NS) 2 SCR ′ . [ 15 ] [ 14 ] With electron-rich alkenes , S 4 N 4 behaves as a Diels-Alder diene. [ 14 ]
Passing gaseous S 4 N 4 over silver metal yields the low temperature superconductor polythiazyl or polysulfurnitride (transition temperature (0.26±0.03) K [ 16 ] ), often simply called "(SN) x ". In the conversion, the silver first becomes sulfided, and the resulting Ag 2 S catalyzes the conversion of the S 4 N 4 into the four-membered ring S 2 N 2 , which readily polymerizes . [ 1 ]
Oxidation of S 4 N 4 with elemental chlorine gives thiazyl chloride , [ citation needed ] but milder reagents give S 4 N + 3 :
That cation is relatively non- electrophilic and planar, with a delocalized π system . However, it adds triphenylphosphine to give [S(NPPh 3 ) 3 ] 3+ [Cl − ] 3 , a triimide analogue to sulfur trioxide . Conversely, S 4 N + 3 salts react with aluminum azide to recover S 4 N 4 . [ 14 ]
Treatment with tetramethylammonium azide produces the similar 10-π heterocycle [S 3 N 3 ] − :
In a related reaction, the use of the bis(triphenylphosphine)iminium azide gives a salt containing the blue [NS 4 ] − anion: [ 13 ]
[NS 4 ] − has a chain structure approximated by the resonance [S=S=N−S−S − ] ↔ [ − S−S−N=S=S] .
Reaction with piperidine generates [S 4 N 5 ] − :
A related cation is also known, i.e. [S 4 N 5 ] + .
Triphenylphosphine abstracts a sulfur atom, replacing it with another triphenylphosphine moiety: [ 14 ]
S 4 N 4 is a categorized as a primary explosive that is shock and friction sensitive. While comparable to pentaerythritol tetranitrate (PETN) in terms of impact sensitivity, its friction sensitivity is equal to or even lower than lead azide. [ 17 ] Purer samples are more shock-sensitive than those contaminated with elemental sulfur. [ 9 ] [ 7 ] | https://en.wikipedia.org/wiki/Tetrasulfur_tetranitride |
Tetraterpenes are terpenes consisting of eight isoprene units and have the molecular formula C 40 H 64 . [ 1 ] Tetraterpenoids (including many carotenoids) are tetraterpenes that have been chemically modified, as indicated by the presence of oxygen-containing functional groups.
Phytoene is biosynthesized via the head-to-head condensation of two GGPP molecules. [ 2 ] One group of tetraterpenes, and possibly the most studied one, is the carotenoids pigments. Carotenoids have important biological functions, with roles in light capture, antioxidative activity and protection against free radicals, synthesis of plant hormones and as structural components of the membranes. Aside their biological relevance, carotenoids are also high-value compounds for the food and pharmaceutical industries. Carotenoids are biosynthesized by photosynthetic and non-photosynthetic organisms; however, in photosynthetic organisms, they are essential components as accessory pigments for the light-harvesting reaction centers. [ 3 ] [ 4 ] [ 5 ] Xanthophylls are another group of tetraterpene pigments distributed widely in nature.
This biochemistry article is a stub . You can help Wikipedia by expanding it . | https://en.wikipedia.org/wiki/Tetraterpene |
Tetrathiafulvalene ( TTF ) is an organosulfur compound with the formula H 2 C 2 S 2 C=CS 2 C 2 H 2 . It is the parent of many tetrathiafulvenes. Studies on these heterocyclic compound contributed to the development of molecular electronics , although no practical applications of TTF emerged. TTF is related to the hydrocarbon fulvalene ( H 4 C 4 C=CC 4 H 4 ) by replacement of four CH groups with sulfur atoms. Over 10,000 scientific publications discuss TTF and its derivatives. [ 2 ]
The high level of interest in TTFs spawned many syntheses of TTF and its analogues. [ 3 ] [ 2 ] Most preparations entail the coupling of cyclic C 3 S 2 building blocks such as 1,3-dithiole -2-thion or the related 1,3-dithiole-2-ones. For TTF itself, the synthesis begins with the cyclic trithiocarbonate H 2 C 2 S 2 C=S ( 1,3-dithiole-2-thione ), which is S -methylated and then reduced to give H 2 C 2 S 2 CH(SCH 3 ) (1,3-dithiole-2-yl methyl thioether), which is treated as follows: [ 4 ]
Protonolysis of a thioether:
Followed by deprotonation of the dithiolium cation with triethylamine :
Bulk TTF itself has unremarkable electrical properties. Distinctive properties are, however, associated with salts of its oxidized derivatives, such as salts derived from TTF + .
The high electrical conductivity of TTF salts can be attributed to the following features of TTF:
Each dithiolylidene ring in TTF has 7π electrons: 2 for each sulfur atom, 1 for each sp 2 carbon atom. Thus, oxidation converts each ring to an aromatic 6π-electron configuration, consequently leaving the central double bond essentially a single bond, as all π-electrons occupy ring orbitals.
The salt [TTF + ]Cl − was reported to be a semiconductor in 1972. [ 6 ] Subsequently, the charge-transfer salt [TTF] TCNQ was shown to be a narrow band gap semiconductor. [ 7 ] X-ray diffraction studies of [TTF][TCNQ] revealed stacks of partially oxidized TTF molecules adjacent to anionic stacks of TCNQ molecules. This "segregated stack" motif was unexpected and is responsible for the distinctive electrical properties, i.e. high and anisotropic electrical conductivity . Since these early discoveries, numerous analogues of TTF have been prepared. Well studied analogues include tetramethyltetrathiafulvalene (Me 4 TTF), tetramethylselenafulvalenes (TMTSFs), and bis(ethylenedithio)tetrathiafulvalene (BEDT-TTF, CAS [66946-48-3]). [ 8 ] Several tetramethyltetrathiafulvalene salts (called Fabre salts ) are of some relevance as organic superconductors . | https://en.wikipedia.org/wiki/Tetrathiafulvalene |
The tetrathionate anion , S 4 O 2− 6 , is a sulfur oxyanion derived from the compound tetrathionic acid, H 2 S 4 O 6 . Two of the sulfur atoms present in the ion are in oxidation state 0 and two are in oxidation state +5. Alternatively, the compound can be viewed as the adduct resulting from the binding of S 2− 2 to SO 3 . Tetrathionate is one of the polythionates , a family of anions with the formula [S n (SO 3 ) 2 ] 2− . [ 1 ] Its IUPAC name is 2-(dithioperoxy)disulfate , and the name of its corresponding acid is 2-(dithioperoxy)disulfuric acid . The Chemical Abstracts Service identifies tetrathionate by the CAS Number 15536-54-6.
Tetrathionate is a product of the oxidation of thiosulfate , S 2 O 2− 3 , by iodine , I 2 :
The use of bromine instead of iodine is dubious as excess bromine will oxidize the thiosulfate to sulfate.
Tetrathionate's structure can be visualized by following three edges of a rectangular cuboid , as in the diagram below. The structure shown is the configuration of S 4 O 2− 6 in BaS 4 O 6 ·2H 2 O and Na 2 S 4 O 6 ·2H 2 O. Dihedral S–S–S–S angles approaching 90° are common in polysulfides .
Compounds containing the tetrathionate anion include sodium tetrathionate , Na 2 S 4 O 6 , potassium tetrathionate , K 2 S 4 O 6 , and barium tetrathionate dihydrate , BaS 4 O 6 ·2H 2 O.
As other species of sulfur at intermediate oxidation state , such as thiosulfate, tetrathionate can be responsible for the pitting corrosion of carbon steel and stainless steel .
Tetrathionate has also been found to serve as a terminal electron acceptor for Salmonella enterica serotype Typhimurium, whereas existing thiosulfate in the small intestines of mammals is oxidized by reactive oxygen species released by the immune system (mainly NADPH oxidase produced superoxide ) to form tetrathionate. This aids in the growth of the bacterium, helped by the inflammatory response. [ 2 ]
This corrosion -related article is a stub . You can help Wikipedia by expanding it . | https://en.wikipedia.org/wiki/Tetrathionate |
Tetrazene ( 1-(5-tetrazolyl)-3-guanyl tetrazene hydrate ) [ 2 ] is an explosive material used for sensitization of priming compositions . It is a derivative of the compound with the IUPAC name tetrazene .
Tetrazene is slightly more impact-sensitive than mercury fulminate . When pressed enough, its sensitivity is reduced or destroyed; this is known as dead pressing. It also decomposes in boiling water. In contact with fire, it readily explodes , producing large amounts of black smoke . It is prepared by reacting sodium nitrite with an aminoguanidine salt dissolved in acetic acid at 30–40 °C.
The decomposition of tetrazene is quite rapid around 90 °C. A sample of tetrazene was heated in an oven at 90 °C and its rate of thermal decomposition was monitored by infrared and ultraviolet spectroscopy. [ 3 ] The thermal decomposition reaction is autocatalytic and it is likely that the same reaction can occur at even lower temperatures, however at much slower rates.
Many explosives are considered to be highly sensitive to mechanical stimuli such as impact , friction , stab, heat , static electricity , flame, etc. Since explosive compounds are subject to friction practically every time they are handled, it is of particular interest to be aware of the sensitivity to friction. The sensitivity of tetrazene was determined using a FSKM-PEx friction sensitivity tester. [ 4 ] The probability of ignition of tetrazene is 100 percent likely at 27N of frictional force. [ 4 ]
Instances of occupational rhinitis , dermatitis , and asthma have been reported due to prolonged exposure to tetrazene. [ 5 ] | https://en.wikipedia.org/wiki/Tetrazene_explosive |
Triphenyl tetrazolium chloride ( TTC ), or simply tetrazolium chloride (with the formula 2,3,5-triphenyl-2H-tetrazolium chloride) is a redox indicator commonly used in biochemical experiments especially to indicate cellular respiration . It is a white crystalline powder, soluble in water, ethanol and acetone but insoluble in ether .
In the TTC assay (also known as TTC test or tetrazolium test), TTC is used to differentiate between metabolically active and inactive tissues. The white compound is enzymatically reduced to red TPF (1,3,5-triphenylformazan) in living tissues due to the activity of various dehydrogenases (enzymes important in oxidation of organic compounds and thus cellular metabolism), while it remains as white TTC in areas of necrosis since these enzymes have been either denatured or degraded.
For this reason, TTC has been employed in autopsy pathology to assist post-mortem identification of myocardial infarctions. Healthy viable heart muscle will stain deep red from the cardiac lactate dehydrogenase; while areas of potential infarctions will be more pale.
Note: TTC is somewhat heat and light unstable, so avoid these environments as much as possible.
This article about an aromatic compound is a stub . You can help Wikipedia by expanding it . | https://en.wikipedia.org/wiki/Tetrazolium_chloride |
In organic chemistry , a tetrose is a monosaccharide with 4 carbon atoms. They have either an aldehyde ( −CH=O ) functional group in position 1 ( aldotetroses ) or a ketone ( >C=O ) group in position 2 ( ketotetroses ). [ 1 ] [ 2 ]
The aldotetroses have two chiral centers ( asymmetric carbon atoms) and so 4 different stereoisomers are possible. There are two naturally occurring stereoisomers, the enantiomers of erythrose and threose having the D configuration but not the L enantiomers. The ketotetroses have one chiral center and, therefore, two possible stereoisomers: erythrulose ( L - and D -form). Again, only the D enantiomer is naturally occurring.
There are a few known ways that tetrose sugars are used in nature. Some are seen in metabolic pathways and others are known to affect certain enzymes.
One of the metabolic pathways that a tetrose is involved in is the Pentose Phosphate Pathway . [ 3 ] In the Pentose Phosphate Pathway, there is an oxidative stage and a non-oxidative stage. [ 4 ] A tetrose sugar, D-erythrose , is utilized in the non-oxidative stage, where D-ribulose 5-phosphate is generated into a 6 carbon sugar ( fructose 6-phosphate ) and a 3 carbon sugar ( glyceraldehyde 3-phosphate ). [ 4 ] Both of these molecules can be used elsewhere in the body.
D-erythrose 4-phosphate is generated as a product of a reaction called transaldolation. [ 5 ] In the Pentose Phosphate Pathway, a transaldolase removes the first 3 carbon molecules of sedoheptulose 7-phosphate and places them onto a glyceraldehyde 3-phosphate. [ 4 ] The transaldolase utilizes a Schiff base to perform a reverse aldol reaction and a forward aldol reaction in its mechanism, generating an erythrose 4-phosphate and fructose 6-phosphate . [ 4 ] The erythrose 4-phosphate is an important intermediate in the Pentose Phosphate Pathway because it is then used in the final non-oxidative step of the pathway.
The final non-oxidative step of the pathway is a transketolase reaction. A transketolase utilizes a thiamine pyrophosphate , or TPP cofactor, to break the unfavorable bond between the carbon in a carbonyl and the alpha carbon . [ 4 ] TPP attacks a xylulose 5-phosphate molecule and facilitates the cleavage of the bond between the C2 (carbonyl carbon) and the C3 (alpha carbon), where glyceraldehyde 3-phosphate is released. [ 4 ] Then, C2 can attack erythrose 4-phosphate, which forms fructose 6-phosphate. [ 4 ] Both of the products of this reaction can enter the gluconeogenesis pathway to regenerate glucose .
A tetrose diphosphate molecule, D-threose 2,4-diphosphate, was discovered to be an inhibitor of glyceraldehyde 3-phosphate dehydrogenase . [ 3 ] Glyceraldehyde 3-phosphate dehydrogenase is the sixth enzyme used in the glycolysis pathway, and its function is to convert glyceraldehyde 3-phosphate into 1,3-bisphosphoglycerate . [ 6 ] This tetrose diphosphate molecule inhibits the G3P dehydrogenase from performing catalysis because it oxidizes the enzyme by binding to it at the active site. [ 7 ] When tetrose diphosphate is bound to the enzyme, the active site of the enzyme is blocked; therefore phosphorolysis of G3P is unable to occur. High concentrations of tetrose diphosphate must be used to outcompete the substrate, G3P, and block the function of G3P dehydrogenase. With the function of glyceraldehyde 3-phosphate dehydrogenase lost, glycolysis cannot proceed. [ 6 ]
D-erythrose 4-phosphate was found to be an inhibitor of phosphoglucose isomerase . [ 8 ] Phosphoglucose isomerase is the second enzyme in the glycolysis pathway, and its role is to convert glucose 6-phosphate into fructose 6-phosphate. [ 6 ]
In both of these cases, the tetrose is an inhibitor of an enzyme in the glycolysis pathway, preventing it from proceeding onward.
This biochemistry article is a stub . You can help Wikipedia by expanding it . | https://en.wikipedia.org/wiki/Tetrose |
2,4,6-Trinitrophenylmethylnitramine or tetryl ( C 7 H 5 N 5 O 8 ) is an explosive compound used to make detonators and explosive booster charges.
Tetryl is a nitramine booster explosive, though its use has been largely superseded by RDX . Tetryl is a sensitive secondary high explosive used as a booster, a small charge placed next to the detonator in order to propagate detonation into the main explosive charge.
Tetryl is a yellow crystalline solid powder material, practically insoluble in water but soluble in acetone , benzene and other solvents. When tetryl is heated, it first melts, then decomposes and explodes. It burns readily and is more easily detonated than ammonium picrate [ 3 ] or TNT , being about as sensitive as picric acid . It is detonated by friction, shock, or spark. It remains stable at all temperatures which may be encountered in storage. It is generally used in the form of pressed pellets, and has been approved as the standard bursting charge for small-caliber projectiles, since it gives much better fragmentation than TNT. It has an explosive velocity of 23,600–23,900 feet per second (7200–7300 m/s). Tetryl is the basis for the service tetryl blasting caps necessary for positive detonation of TNT. A mixture of mercury fulminate and potassium chlorate is included in the cap to ensure detonation of tetryl. [ 3 ]
The most toxic ordnance compounds, tetryl and 1,3,5-TNB, are also the most degradable. Therefore, these chemicals are expected to be short-lived in nature, and environmental impacts would not be expected in areas that are not currently subject to chronic inputs of these chemicals. Tetryl decomposes rapidly in methanol /water solutions, as well as with heat. All aqueous samples expected to contain tetryl should be diluted with acetonitrile prior to filtration and acidified to pH < 3. All samples expected to contain tetryl should not be exposed to temperatures above room temperature. In addition, degradation products of tetryl appear as a shoulder on the 2,4,6-TNT peak. Peak heights rather than peak areas should be used when tetryl is present in concentrations that are significant relative to the concentration of 2,4,6-TNT. [ 3 ]
Tetryl was used mainly during World Wars I and II and later conflicts. Tetryl is usually used on its own, though can sometimes be found in compositions such as tetrytol . Tetryl is no longer manufactured or used in the United States, but can still be found in legacy munitions such as the M14 anti-personnel landmine . [ 4 ]
Dutch chemist Karel Hendrik Mertens originally synthesized the compound as a part of his doctoral dissertation published in 1877 [ 5 ] by slowly mixing dimethylaniline with concentrated nitric acid in the presence of sulfuric acid , and it's still a viable lab technique. However, in the 1930s a more economical route was commercialized, where methylamine produced by the Smoleński method (developed after WWI) reacts with dinitrochlorobenzene to make dinitromethylaniline which is then easily nitrated without byproducts.
Although tetryl is among the most toxic explosive compounds, it is very short-lived, especially if in fact detonated. This combined with the fact that the health impacts of this compound are largely unstudied, not much is known about any health problems that this compound may cause.
Epidemiological data shows that tetryl has most effect on the skin, acting as a strong irritant. [ 6 ] Symptoms of skin sensitization such as dermatitis, itch, erythema, etc. may occur. [ 7 ] Tetryl can also affect mucous membranes, the upper respiratory tract, and possibly the liver. | https://en.wikipedia.org/wiki/Tetryl |
Tetrytol is a high explosive , comprising a mixture of tetryl and TNT . [ 1 ] Typically, the proportion of ingredients (by weight) is 65%, 70%, 75% or 80% tetryl to 35%, 30%, 25% or 20% TNT. Tetryl and TNT do form a eutectic with a setting point of 67.5 °C, which consists of 55% tetryl and 45% TNT. [ 2 ] Hence, cast tetrytol charges consist of solidified suspensions of crystalline tetryl in the solid tetryl-TNT-eutectic. Tetrytol is more sensitive than TNT and less sensitive than tetryl to impact. [ 1 ] The detonation velocity of unconfined cast cylindrical charges (1 inch diameter) of tetrytol is between 7290 and 7410 m/s with an average of 7350 m/s for tetrytol 75/25 and 7340 m/s for tetrytol 65/35. [ 2 ] For comparison, cylindrical charges of cast pure TNT of similar dimensions are reported to detonate with a velocity of between 6680 and 6990 m/s. [ 3 ]
Applications of tetrytol are usually military in nature e.g. burster tubes for chemical weapons (e.g. nerve agent shells ), blocks of demolition explosives and cast shaped charges . [ 2 ]
Dry tetrytol is compatible with copper, brass, aluminum, magnesium, stainless steel, mild steel coated with acid proof paint and mild steel plated with copper, cadmium, zinc or nickel. Magnesium-aluminum alloys are slightly affected by dry tetrytol. Wet tetrytol is compatible with stainless steel and mild steel coated with acid proof black paint. Copper, brass, aluminum, magnesium, magnesium-aluminum alloy, mild steel and mild steel plated with cadmium, copper, zinc or nickel are slightly affected by wet tetrytol. [ 4 ]
When stored below 65 °C (149 °F) Tetrytol does not change stability, acid content, sensitivity or brisance. However, temperatures at 65 °C or above will allow the formation of an oily extrudate and distortion of blocks. Although tetryl undergoes partial decomposition on melting, the melting of tetrytol does not have the same effect. Even when Tetrytol is melted and solidified numerous times it causes no change in freezing point, sensitivity to impact or 100 °C vacuum stability test value. [ 2 ]
Tetrytol has been discontinued by the U.S. due to the exudation and low stability at elevated storage temperatures. [ 2 ] | https://en.wikipedia.org/wiki/Tetrytol |
Teuthology (from Greek τεῦθος, " cuttlefish , squid ", and -λογία, -logia ) [ 1 ] is the study of cephalopods , which are members of the class Cephalopoda in the phylum Mollusca . Some common examples of cephalopods are octopus , squid , and cuttlefish . Teuthology is a large area of study that covers cephalopod life cycles, reproduction, evolution, anatomy, and taxonomy.
Teuthology is a specific branch of malacology , the study of molluscs . A teuthologist is a scientist who studies teuthology.
The publication of the English translation of Albin O Ebersbach's thesis on the detailed descriptions of cirrate octopods marks an expansion of access to important taxonomical identifying information in teuthology. [ 2 ]
The third paper in the series led by Tristian Joseph Verhoeff revisiting cirrate octopods is published. [ 3 ]
Several papers describing new species of cephalopods were published this year. Two of the papers were the beginning of the series led by Tristian Joseph Verhoeff describing new cirrate octopods discovered around Australia and New Zealand. [ 4 ] [ 5 ] The third paper describes two new Sepiolina species also discovered in Australian waters. [ 6 ]
The Cephalopod International Advisory Council (CIAC) is a group founded by teuthologists to discuss advancements and growth of cephalopod research. [ 7 ] [ more detail needed ]
This cephalopod -related article is a stub . You can help Wikipedia by expanding it . | https://en.wikipedia.org/wiki/Teuthology |
Teva API is an international pharmaceutical company headquartered in Israel . Teva API is a stand-alone business unit of Teva Pharmaceutical Industries limited , the largest generic drug manufacturer in the world [ 1 ] and one of the 15 largest pharmaceutical companies worldwide. [ 2 ]
On top of supplying a major share of Teva's own needs, the Teva API division is an active competitor in world markets, investing both in the development of new products, manufacturing processes and in the upgrading of production facilities. In 2014, Teva API's sales to third parties totaled $724 million. In recent years growth occurred in all of Teva API's principal geographical markets: North America , Europe and International. [ 3 ]
At the heart of the API division is the Israel-based Teva-Tech, formerly known as the Asia and Plantex plants which manufacture, develop and market raw materials for pharmaceuticals.
Teva api has grown by acquiring manufacturing and development facilities around the world. Today, Teva api operates 21 plants and sales offices worldwide. Major Teva api's acquisitions:
[ 7 ]
The R&D group at teva api consists of a team of over 760 top scientists located in 7 development centers worldwide: A large center in Israel (synthetic products and peptides ), a large center in Hungary ( fermentation and semi-synthetic products), and a facility in India and additional sites in Italy , Croatia , Mexico and the Czech Republic (development of high potency API).
teva api's R&D focuses on the development of processes for the manufacturing of API, including intermediates, chemical and biological (fermentation), which are of interest to the generic drug industry, as well as Teva's proprietary drugs. The API R&D division also seeks methods to continuously reduce API production costs, enabling teva api to improve its cost structure. [ citation needed ]
Teva has 15 API production facilities located in Israel, Hungary, Italy, the U.S., the Czech Republic, India, Mexico, Puerto Rico, Monaco, China and Croatia. [ 8 ] TAPI's holds expertise in a variety of production technologies, including chemical synthesis , semi-synthetic fermentation, enzymatic synthesis, high potent manufacturing, plant extract technology, synthetic peptides , vitamin D derivatives and prostaglandins . Also, its advanced technology and expertise in the field of solid state particle technology enables it to meet specifications for particle size distribution (PSD), bulk density , specific surface area, polymorphism , as well as other characteristics. [ 9 ]
Teva's API facilities meet all applicable current Good Manufacturing Practices (cGMP) requirements under U.S., European, Japanese, and other applicable quality standards. In some of the products that are sold in the U.S., TAPI utilizes controlled substances and therefore must meet the requirements of the Controlled Substances Act and the related regulations administered by the Drug Enforcement Administration . [ 10 ]
Teva api produces approximately 400 active pharmaceutical ingredients covering a wide range of products, including respiratory , cardiovascular , anti-cholesterol , central nervous system , dermatological , hormones , anti-inflammatory , oncology , immunosuppressants and muscle relaxants . Its API intellectual property portfolio includes over 1,200 granted patents and pending applications worldwide. [ 11 ] | https://en.wikipedia.org/wiki/Teva_Active_Pharmaceutical_Ingredients |
Teva Pharmaceutical Industries Ltd. (also known as Teva Pharmaceuticals ) is an Israeli multinational pharmaceutical company. Teva specializes primarily in generic drugs , but other business interests include branded-drugs, active pharmaceutical ingredients (APIs) and, to a lesser extent, contract manufacturing services and an out-licensing platform. [ 3 ]
Teva's primary branded products include Austedo ( deutetrabenazine ) which is used for the treatment of chorea associated with Huntington's disease and tardive dyskinesia ; and Ajovy ( fremanezumab ), used for the preventive treatment of migraine in adults. Additional branded drugs sold by Teva include Copaxone, Bendeka and Treanda, all of which are primarily sold in the United States.
Teva is listed on the Tel Aviv Stock Exchange and the New York Stock Exchange . Its manufacturing facilities are located in Israel, North America, Europe, Australia, and South America. The company is a member of the Pharmaceutical Research and Manufacturers of America (PhRMA). [ 4 ] [ 5 ]
Teva Pharmaceuticals is the largest generic drug manufacturer in the world. Overall, Teva is the 26th largest pharmaceutical company in the world. [ 6 ] Teva has a history of legal trouble in relation to collusion and price-fixing to inflate prices for drugs. [ 7 ] In 2023, Teva paid the largest fine to date for a domestic antitrust cartel in relation to a criminal investigation by the US Department of Justice into the company's price-fixing. [ 8 ] [ 9 ]
One of its early shareholders, after the company was quoted on the Tel Aviv exchange, was the late British press tycoon Robert Maxwell . [ 10 ]
Teva's earliest predecessor was SLE, Ltd., a wholesale drug business founded in 1901 in Ottoman Empire's Mutasarrifate of Jerusalem . SLE Ltd. took its name from the initials of its three cofounders: Chaim Salomon, Moshe Levin and Yitschak Elstein, and used camels to make deliveries. [ 11 ] During the 1930s, new immigrants from Europe founded several pharmaceutical companies including Teva and Zori. In the 1930s, Salomon, Levin, and Elstein Ltd. also founded Assia, a pharmaceutical company. [ 12 ]
Teva Pharmaceutical Industries took its present form through the efforts of Günther Friedländer and his aunt Else Kober on May 1, 1935. The original registration was under the name Teva Middle East Pharmaceutical & Chemical Works Co. Ltd. in Jerusalem, then part of Mandatory Palestine . Friedländer was a German pharmacist, botanist and pharmacognosist, who immigrated to Mandatory Palestine in 1934.
The company was built with an investment of £ 4,900, which came from the family's own capital and partly from loans from other German immigrants. Capital shortage led to the joining of the banker Alfred Feuchtwanger as a partner in Teva, who received 33% of the shares in return for his investment. [ 13 ]
Friedländer's business philosophy opined that the pharmaceutical industry has a reliable basis in difficult economic times, since "A Jewish mother will always buy medicine for her children". In the Second World War , the company provided medicine to the allied forces and in particular to the British army present in the Middle East . After the war, Sir Alan Gordon Cunningham , the last of the High Commissioners for Palestine and Transjordan , visited Teva on behalf of the Secretary of State for the Colonies . His visit promoted Teva's reputation in the pharmaceutical market and created a momentum for Teva's development.
During Mandatory Palestine , Teva exported its medical products to Arab countries. In 1941, Friedländer presented Teva products in an exhibition held in Cairo , Egypt . The exhibition was sponsored by the General Agent and Sole Distribution of medicine in Egypt and Sudan , Syria and Lebanon . Later on, Teva exported its products to the US , Soviet Union ( USSR ), health institutes in Denmark , Czechoslovakia , Persia and Burma .
In 1951, Feuchtwanger initiated an initial public offering to raise capital through the newly founded Tel-Aviv Stock Exchange and Teva became a public company . [ 11 ] In 1954, Teva received a Certificate Excellence in Training award from the Israeli President, Yitzhak Ben Zvi . [ citation needed ] In 1964, Teva partnered with Sintex, a company from Mexico, and Schering Plough . [ citation needed ]
In 1964, Assia and Zori merged and in 1968 acquired a controlling stake in Teva. [ 14 ] In 1976, the three companies merged into the modern-day Teva Pharmaceutical Industries Ltd. [ 14 ] In 1980, Teva acquired Ikapharm, then Israel's second largest drug manufacturer. [ 15 ]
In 1980, Teva acquired Plantex . [ 12 ]
In 1982, Teva was granted approval by the U.S. Food and Drug Administration (FDA) for its Kfar Saba manufacturing plant. [ 16 ]
In 1995, Teva acquired Biogal Gyógyszergyár Rt. ( Debrecen , Hungary ) and acquired ICI ( Italy ). [ 17 ]
In 2000, Teva acquired Canada-based Novopharm . [ 18 ]
In October 2003, Teva announced its intentions to acquire Sicor Inc. for $3.4 billion. [ 19 ] Following the announcement, the acquisition was completed on January 22, 2004, which marked Teva's entry into biosimilars' market. [ 20 ]
In 2005, Teva opened a new, state-of-the-art pharmaceutical manufacturing plant in Har Hotzvim , a technology park in Jerusalem . The plant received FDA approval in early 2007. [ 21 ] Teva entered the Japanese market in 2005 and in 2008 established a generics joint venture with Kowa . [ 22 ] [ 23 ]
In January 2006, Teva acquired its U.S. rival Ivax Corporation for $7.4 billion. [ 24 ] [ 25 ] In 2008, sales totalled $11.08 billion, $13.9 billion in 2009, and in 2010 total sales rose to $16.1 billion, of which a major portion was in Europe and North America. On December 23, 2008, Teva acquired Barr Pharmaceuticals for $7.5 billion, making Barr and Pliva (which Barr bought earlier) part of Teva. [ 26 ]
On March 18, 2010, Teva said it planned to acquire German generic Ratiopharm for US$5 billion. The deal was completed in August 2010, significantly expanding Teva's European coverage. [ 21 ] [ 27 ] [ 28 ] [ 29 ] In May 2011, Teva bought Cephalon for US$6.8 billion. [ 30 ] The same month, Teva announced the ¥40 billion purchase of a majority stake in Japanese generic drug company Taiyo Pharmaceutical Industry , a move to secure a Japan-local production facility. [ 22 ] Teva completed the $934 million acquisition in July 2011. [ 31 ] In June 2013, Teva acquired US firm MicroDose Therapeutx for $40 million with as much as $125 million being paid in regulatory and developmental milestones [ 32 ] In 2010, Teva announced that it would build its main distribution center for the Americas in Philadelphia, PA, and was considering opening its US headquarters in the area. [ 21 ] In 2010, it had 39,660 employees. In Israel, the number of workers rose 7.5% by 6,774. [ 33 ] In October 2010, Teva entered a licensing agreement with BioTime to develop and market BioTime's OpRegen for the treatment of age-related macular degeneration , [ 34 ] an effort that in 2013 received $1.5 billion in funding from Israel's Office of the Chief Scientist . [ 35 ]
In May 2011, Teva announced it would purchase Cephalon for US$6.8 billion. [ 36 ]
In January 2014, Teva acquired NuPathe , after outbidding Endo , for $144 million. [ 37 ] In June 2014, Teva acquired Labrys Biologics for up to $825 million, [ 38 ] the aim being to strengthen the company's migraine pipeline through addition of LBR-101, an anti- CGRP monoclonal antibody therapeutic . [ 39 ]
In March 2015, Teva acquired Auspex Pharmaceuticals for $3.5 billion growing its CNS portfolio. [ 40 ] In April, Teva offered to acquire Mylan for $40 billion, [ 41 ] only a fortnight after Mylan offered to buy Perrigo for $29 billion. [ 42 ] Teva's offer for Mylan was contingent on Mylan abandoning its pursuit of Perrigo. [ 43 ] Mylan stated in June 2015 that Teva's disclosure that it had a 1.35 percent stake in Mylan violated US antitrust rules. [ 44 ] In October, the company acquired Mexico-based Representaciones e Investigaciones Medicas (Rimsa) for around $2.3 billion. [ 45 ] In the same month Teva acquired Gecko Health Innovations . [ 46 ] In November 2015, the company announced it would collaborate with Heptares Therapeutics with its work on small-molecule calcitonin gene-related peptide antagonists for migraine treatment, with the deal generating up to $410 million. [ 47 ]
Teva Active Pharmaceutical Ingredients (TAPI) operates within Teva as a stand-alone business unit. In 2009, TAPI's sales to third parties totaled $565 million, and in 2010 sales rose by 13% to a total of $641 million. [ citation needed ]
In July 2017, it was reported that Pascal Soriot , CEO of AstraZeneca since 2012, would become the next CEO of Teva, succeeding Erez Vigodman, [ 48 ] [ 49 ] however this was soon refuted. [ 50 ] As of August 2017, the company has struggled to attract a new CEO, leading to mounting questions for the board. [ 51 ] In August 2017, the board of directors announced a 75% cut in the dividend, reflecting declining profitability, and the share price fell by almost half in the days following. [ 52 ] [ 53 ] As of September 11, 2017, Teva remained the "world's biggest seller of generics medicines." On September 11, 2017, it was reported that they had selected Kåre Schultz as the new Teva CEO. [ 54 ] A day later the company announced it would sell its Paragard contraceptive brand to Cooper Cos for $1.1 billion, with the funds being used to pay down debt. [ 55 ] Days later the company announced further divestments: a sale of contraception, fertility, menopause and osteoporosis products to CVC Capital Partners Fund VI for $703 million and its emergency contraception brands for $675 million to Foundation Consumer Healthcare . [ 56 ] By December, the company had announced a drastic 25 percent workforce reduction (greater than 14,000 employees) as part of a two-year cost-reduction strategy. [ 57 ] Following considerable lobbying by the Israeli Government, from whom Teva received considerable tax breaks, [ 58 ] and from Israel's labor federation, the Histadrut, Teva agreed to delay some of the layoffs in Israel. [ 59 ]
In October 2019, Teva faced criticism for making a "business decision to discontinue the drug" Vincristine , essential for the treatment of most childhood cancers according to the Food and Drug Administration. [ 60 ] [ 61 ]
In July 2015, Allergan agreed to sell its generic drug business (Actavis Generics [ 62 ] ) to Teva for $40.5 billion [ 63 ] [ 64 ] [ 65 ] ($33.75 billion in cash and $6.75 billion worth of shares). [ 66 ] As a result, Teva dropped its pursuit of Mylan . In order for the deal to gain regulatory approval, Teva sold off a number of assets, including a portfolio of five generic drugs to Sagent Pharmaceuticals for $40 million, as well as a further eight medicines to Dr. Reddy's in a $350 million deal. [ 62 ] Teva also sold a further 15 marketed generics, as well as three others that were close to market, for $586 million to Impax Laboratories . [ 67 ] [ 68 ] In July, Teva sold off a further 42 products to Australian generics company, Mayne Pharma , for $652 million; the deal moved Mayne up 50 spots, into the top-25 companies of US generic companies. [ 69 ] As part of the deal Teva will seek to raise $20 to $25 billion [ 70 ] through a bond sale. [ 71 ]
After completing the $39 billion acquisition of Actavis Generics, Teva announced another, smaller, deal with Allergan, agreeing to acquire its generic distribution business Anda for $500 million. [ 72 ]
On October 21, 2011, Par Pharmaceutical has sealed the deal to three products from Teva Pharmaceutical Industries, which the Israeli firm was required by the US Federal Trade Commission to divest before it could acquire US biotech Cephalon for $6.8 billion. [ 73 ]
Following the acquisition of Allergan plc generic division some assets have been sold off to meet US antitrust requirements. [ 74 ] In June 2016 Indian pharmaceutical company Dr. Reddy's Laboratories Ltd bought 8 (ANDA) Abbreviated New Drug Applications for $350 million in cash. [ 75 ] Also in June 2016 Teva sold two ANDAs to Indian pharmaceutical company Zydus Cadilla, strengthening its US portfolio. [ 76 ] On June 21, 2016, American pharmaceutical company Amneal Pharmaceutical previously known as Impax Laboratories bought a portfolio of generic drugs from Teva Pharmaceutical Industries for about $586 million. [ 77 ] On July 29, Cipla an Indian pharmaceutical company bought three products from Teva. [ 78 ] Indian pharmaceutical company, Aurobindo, was in the race to buy some Teva assets. In October 2016, Teva has sold off part of its UK and Ireland generic business to Indian pharmaceutical company Intas Pharma for 600 million pounds (5083 crore Indian rupees) in cash. [ 79 ] In August 2016, Australia pharmaceutical company Mayne Pharmaceutical bought a portfolio of drugs from pharmaceutical giant Teva Pharmaceuticals last year for $845 million Australian dollars. [ 80 ] In February 2018, Teva Pharmaceutical Industries Ltd has completed the sale of a portfolio of products within its global women's health business across contraception, fertility, menopause and osteoporosis for $703 million in cash to CVC Capital Partners Fund VI. [ 81 ] Teva also agreed to sell its Plan B One-Step and its brands of emergency contraception to Foundation Consumer Healthcare for $675 million in cash. Combined annual net sales of these products were $140 million last year. [ 82 ] It also sold Paragard to a unit of Cooper Companies Inc (COO.N) for $1.1 billion. [ 82 ]
The following is an illustration of the company's major mergers and acquisitions and historical predecessors (this is not a comprehensive list):
Gecko Health Innovations (Acq 2015)
Rimsa (Acq 2015)
Actavis Generics (Generic drug div Allergan, plc , Acq 2015)
Auspex Pharmaceuticals (Acq 2014)
Labrys Biologics (Acq 2014)
NuPathe after (Acq 2014)
MicroDose (Acq 2013)
Taiyo Pharmaceutical Industry (Acq 2011)
Arana Therapeutics (Acq 2009)
ChemGenex Pharmaceuticals (Acq 2011)
Ratiopharm (Acq 2010)
Barr Pharmaceuticals (Acq 2008)
IVAX Corporation (Acq 2006)
Novopharm (Acq 2000)
Plantex (Acq 1980)
Ikapharm (Acq 1980)
Salomon, Levin, and Elstein Ltd (Merged 1976 to form Teva Pharmaceutical Industries Ltd)
Assia (Merged 1976 to form Teva Pharmaceutical Industries Ltd)
Zori (Merged 1976 to form Teva Pharmaceutical Industries Ltd)
Glaxo (Acq 1914)
Margarine Unie (Acq 1924)
Allen & Hanburys (Merged 1976 to form Teva Pharmaceutical Industries Ltd)
Teva holds patents on multiple drugs, including Copaxone , a specialty drug [ 95 ] (for the treatment of multiple sclerosis ), now the world's best selling MS drug, [ 9 ] and Azilect (sold as Agilect in some countries) for treatment of Parkinson's disease . By July 2015, Copaxone held a "31.2 percent shares of total MS prescriptions in the United States." [ 9 ] Teva's new 40 mg version of Copaxone taken three times a week "accounted for 68.5 percent of total Copaxone prescriptions in the United States." [ 9 ] Copaxone accounts for about fifty percent of "Teva's profit and 20 percent of revenue." [ 9 ] Competitors' Glatopa, 20 mg version of Copaxone, is taken once a day. [ 9 ]
In June 2006, Teva received from the FDA a 180-day exclusivity period to sell simvastatin (Zocor) in the U.S. as a generic drug in all strengths except 80 mg. Teva presently [ when? ] competes with the maker of brand-name Zocor, Merck & Co. ; Ranbaxy Laboratories , which has 180-day exclusivity for the 80 mg strength; and Dr. Reddy's Laboratories , whose authorized generic version (licensed by Merck) is exempt from exclusivity.
In June 2010, the company announced it would discontinue its production of propofol , a major sedative estimated to be used in 75% of all US anesthetic procedures. [ 96 ]
In March 2015, Teva sold four anti-cancer compounds to Ignyta Inc. for $41.6 million. As part of the deal Teva sold the following compounds which were then renamed: [ 97 ]
In July 2019, the company stopped production of Vincristine , a critical drug used to treat the most common forms of childhood cancer, and was criticized by media for creating a worldwide shortage of the drug. [ 98 ] On 28 January 2020, the company announced that the Food and Drug Administration (FDA) had approved an autoinjector device for Ajovy ( fremanezumab-vfrm ) injection. [ 99 ]
In 2010s section: Following Russia's invasion of Ukraine in 2022, Teva Pharmaceuticals faced criticism for continuing its operations in Russia despite international sanctions. While the company committed to stopping new investments, its focus on ensuring an uninterrupted supply of medicines has raised ethical concerns, with critics arguing that Teva's presence weakens the impact of sanctions aimed at pressuring Russia economically. [ 100 ] [ 101 ] [ 102 ]
On June 25, 2010, Bayer sued Teva for falsely claiming that Teva's Gianvi was stabilized by betadex as a clathrate , and could consequently be advertised as a generic of Yaz . [ 103 ] [ 104 ] The settlement resulted in Teva changing its product marketing to remove the claim that it used the same ingredients as Yaz. [ 105 ] Bayer's method specifically prevents oxidative degradation of the estrogen, while Teva's does not.
In January 2015, the Supreme Court of the United States decided for Teva on the Copaxone patent in Teva Pharmaceuticals USA, Inc. v. Sandoz, Inc. [ 106 ]
In December 2016, the attorneys general of 20 states filed a civil complaint accusing Teva of a coordinated scheme to artificially maintain high prices for a generic antibiotic and diabetes drug. The complaint alleged price collusion schemes between six pharmaceutical firms including informal gatherings, telephone calls, and text messages. [ 107 ]
In January 2019, the Supreme Court of the United States decided for Teva in Helsinn Healthcare S.A. v. Teva Pharmaceuticals USA Inc. [ 108 ]
On May 11, 2019, Teva Pharmaceuticals USA was one of 19 drug companies sued for price fixing in the United States by 44 states for inflating its prices, sometimes up to 1000%, in an illegal agreement among it and its competitors. [ 7 ] In June 2021, Teva agreed to pay $925M to settle allegations it had engaged in price fixing in Mississippi . [ 109 ] In January 2022, Teva agreed to pay $425M to settle allegations that it had concealed price fixing practices from shareholders. [ 110 ]
In May 2019, Teva Pharmaceuticals USA agreed to pay $85 million to the U.S. state of Oklahoma to settle allegations that it had been overprescribing opioids, marketing them as safe, and downplaying their addictive qualities. [ 111 ]
In July 2019, Teva paid $69 million to settle pay-for-delay claims. [ 112 ]
In January 2020, Teva Pharmaceuticals agreed to pay $54 million to settle allegations under the False Claims Act that it violated the Anti-Kickback Statute by funding improper speaking programs to boost prescriptions. [ 113 ]
In 2021, New York Attorney General Letitia James filed a lawsuit against Teva and several other opioid manufacturers for their alleged contribution to the opioid epidemic in New York. [ 114 ]
In February 2022, Teva agreed to a $225 million settlement with the state of Texas to end claims that it fueled an opioid epidemic in the state by improperly marketing pain medicine. [ 115 ]
In August 2023, Teva admitted to price-fixing charges related to the generic cholesterol drug Pravastatin , and agreed to pay a $225 million fine, after a criminal investigation by the US Department of Justice. [ 8 ] The US Department of Justice stated that the settlement was "the largest to date for a domestic antitrust cartel." [ 116 ]
Also in August 2023, Teva agreed to a legal settlement with US hospitals over its marketing of opioid products that ultimately raised costs for health providers and contributed to the opioid epidemic in the United States . [ 117 ] The lawsuit consisted of roughly 500 hospitals and health providers, resulting in a payment from Teva of $126 million over 18 years.
On October 31, 2024, the European Commission fined Teva €462.6 million "over misuse of the patent system and disparagement to delay [a] rival multiple sclerosis medicine", namely Copaxone (glatiramer acetate). Teva is accused of having attempted to obstacle other producers of glatiramer acetate both by abusing the patent system and by setting up a misinformation campaign targeting other glatiramer producers. [ 118 ]
A full list of products destined for the US market is available from tevagenerics.com . Teva also manufactures generic medications for use outside of the US; Cyproterone acetate [ 119 ] and Moclobemide [ 120 ] being two examples.
In 2018-2019, Teva Pharmaceuticals USA recalled antihypertensive tablets containing valsartan and losartan due to the detection beyond acceptable limit of N -nitrosodiethylamine (NDEA) and N-Nitroso-N-methyl-4-aminobutyric acid (NMBA), respectively, which are probable human carcinogens. [ 124 ] [ 125 ] | https://en.wikipedia.org/wiki/Teva_Pharmaceuticals |
The Texas A&M Institute for Genomic Medicine ( TIGM ) is a research institute of Texas A&M AgriLife Research. It was founded in 2005 under a $50 million award from the Texas Enterprise Fund to accelerate the pace of medical discoveries and foster the development of the biotechnology industry in Texas.
TIGM helps researchers gain faster access to the genetically engineered knockout mice used in medical research. TIGM owns and maintains the world's largest library of embryonic stem cells for C57BL/6 mice. In addition, TIGM has contracted access to the world's largest library of genetically modified 129 mouse cells. The Institute headquarters and laboratory facilities are based on the main campus of Texas A&M University in College Station, Texas . [ 1 ] | https://en.wikipedia.org/wiki/Texas_Institute_for_Genomic_Medicine |
Texas Low Emission Diesel standards (TxLED) are rules regulating the quality of diesel fuels , intended to reduce pollutants (especially NOx ). Since October 31, 2005, diesel fuel to be consumed by engines in 110 counties in Eastern Texas must meet these requirements: [ 1 ]
Alternatively, diesel fuel that complies with the specifications of a California Air Resources Board (CARB) certified alternative diesel formulation that was approved by CARB before January 18, 2005, may be used, as can fuel approved by the Texas Commission on Environmental Quality (TCEQ) that is proven to have emissions equivalent to or less than TxLED compliant fuel. | https://en.wikipedia.org/wiki/Texas_Low_Emission_Diesel_standards |
Texperts was a UK -based SMS question-and-answer service. In December 2008, Texperts was bought by the United States –based Knowledge Generation Bureau , operator of the 118 118 services, a directory services company which had also entered the SMS question-and-answer market. The service was later renamed Kgb Answers and is now defunct.
Re5ult Ltd was launched initially with a subscription-based service called 'Re5ult' on a normal mobile number. However, in August 2004 the service was launched on a premium text code and rebranded as 82ASK. In 2007, Re5ult switched phone numbers and brands again, relaunching the service as Texperts on short code 66000.
Posing the question "How many people [are] alive compared with all who had ever lived?", a Guardian journalist testing the service received an answer within five minutes, with the closest rival answering it in 22 minutes. A similar question asked for "a hotel in Ireland within half an hour of Rosslare en route to Westmeath " which received an answer within 15 minutes; a rival service answered a few minutes sooner and also provided prices which Texperts's response lacked. [ 1 ]
In 2006, Texperts released the book Do Sheep Shrink in the Rain? , subtitled "Over 500 of the most outrageous questions ever asked" , published by Virgin Books . The 256-page paperback is a compilation of questions received and answered by the service. [ 2 ] | https://en.wikipedia.org/wiki/Texperts |
A text-free user interface is a user interface (UI) wholly based on graphical UI techniques and without any writing . Text-free UIs are employed in areas where written language may not be understood by the user. For example, with young children , international UIs where localisation is not feasible or where users may be illiterate . [ 1 ]
This computing article is a stub . You can help Wikipedia by expanding it . | https://en.wikipedia.org/wiki/Text-free_user_interface |
The Text Services Framework (TSF) is a COM framework and API in the Microsoft Windows operating system that supports advanced text input and text processing. It was introduced in Windows XP . The Language Bar is the core user interface for Text Services Framework.
The Text Services Framework is designed to offer advanced language and word processing features to applications. It supports features such as multilingual support, keyboard drivers, handwriting recognition , speech recognition , as well as spell checking and other text and natural language processing functions. It is also downloadable for older Windows operating systems. [ 1 ]
The Language Bar enables text services to add UI elements to the toolbar and enables these elements when an application has focus. From the Language Bar, users can select the input language, and control keyboard input, handwriting recognition and speech recognition.
The language bar also provides a direct means to switch between installed languages, even when a non-TSF-enabled application has focus.
Starting with Windows XP Tablet PC Edition 2005 and Windows Vista , the RichEdit control supports the Text Services Framework. Windows Speech Recognition in Windows Vista is also implemented using the Text Services Framework.
ctfmon ( ctfmon.exe ) is a process used to activate the Alternative User Input Text Input Processor (TIP) and also the Microsoft Language Bar . Ctfmon is also a component of Windows XP , Windows Vista and Windows 7 which enables advanced user input services in applications (pen and ink, speech etc.). [ 4 ] ctfmon.exe in Windows XP has superseded internat.exe (means international ) in Windows 95 , Windows NT 4.0 , Windows 98 and Windows 2000 .
CTF means Common Text Framework (codename Cicero ) according to the leaked Windows XP source code [ 5 ] ) and US 7490296 patent text.
In August 2019, Google Project Zero discovered and publicly exposed a critical security vulnerability in CTF that dated back to its first release in Windows XP. The vulnerability, known as CVE-2019-1162, allows privilege escalation and security boundary traversal. Microsoft patched this vulnerability in August 2019. [ 6 ] [ 7 ] [ 8 ] | https://en.wikipedia.org/wiki/Text_Services_Framework |
Text inferencing describes the tacit or active process of logical induction or deduction during reading. Inferences are used to bridge current text ideas with antecedent text ideas or ideas in the reader's store of prior world knowledge. Text inferencing is an area of study within the fields of cognitive psychology and linguistics . Much of the information extracted from text is not understood as or remembered from things stated directly in that text, but from abstractions, inferences, and higher order understandings of the text material. Thus, inferences help maintain a coherent discourse representation by organizing and making sense of otherwise seemingly disjointed text ideas [ 1 ]
Inferences made in text are generally said to be either "forward" or "backward" in relation to the current text idea. Forward inferences require the reader to bridge the current text idea to prior world knowledge, and are also referred to as "elaborative inferences." Consider the following sentence: [ 2 ] "The director and the cameraman were ready to shoot closeups when suddenly the actress fell from the 14th story." This type of inference is also referred to as a "predictive inference" because the reader is inferring something about events to come. The experimental evidence has suggested that upon reading sentences such as that one, readers activate concepts such as "dead", suggesting that they inferred the actress died. Such an inference almost seems necessary if full comprehension of the story is to occur. Other types of elaborative inferences are inferences regarding characters or instruments described in the text. Predictive inferences are not made as reliably and not last as long in memory as other types of inferences, [ 3 ] and are largely based on the amount of biasing context provided by nearby text ideas [ 4 ]
Backward inferences require the reader to bridge the current text idea to one that occurred earlier in the text. These types of inferences are also referred to as "bridging inferences." For example, if a reader came across the following sentences together, they would need to have inferred that the sentences are related to one-another if they are to make any sense of the text as a whole: "Mary poured the water on the bonfire. The fire went out." [ 5 ] The type of inference drawn here is also called a "causal inference" because the inference made suggests that events in one sentence cause those in the next. Backward inferences can be either logical, in that the reader assumes one occurrence based on the statement of another, or pragmatic, in that the inference helps the reader comprehend the story coherently, like in the previous example. | https://en.wikipedia.org/wiki/Text_inferencing |
Text over IP (or ToIP ) is a means of providing a real-time text (RTT) service that operates over IP-based networks. [ 1 ] It complements Voice over IP ( VoIP ) and Video over IP.
Real-time text is streaming text that is transmitted as it is produced, allowing text to be used conversationally. [ 2 ] Real-time text is defined in ITU-T Multimedia Recommendation F.700 2.1.2.1 . Real-time text is designed for conversational use where people interactively converse with each other. To achieve this, particular user requirements have been specified for the delay of each character and the character loss rate (see F.700 Annex A.3).
Real-time Text over IP can be used:
ToIP is designed around the ITU-T T.140 real-time text presentation layer protocol (defined for H.32x multimedia services). T.140 allows real-time editing of text e.g. by using 'backspace' and retyping. T.140 is based on the ISO 10646-1 character set that is used by most IP text specifications and uses the UTF-8 format.
Transport of ToIP uses the same Real-time Transport Protocol (RTP) as VoIP and Video-over-IP. The text is encoded according to IETF RFC 4103 "RTP Payload for Text Conversation".
RFC 4103 supports an optional forward error correction scheme based on redundant transmission (using RFC 2198). This results in a very low end-to-end packet loss across IP transmission links that have moderately high packet loss. To improve efficiency, text can be buffered for 0.3–0.5 seconds before it is sent whilst still meeting the delay requirements.
RTP is usually transported over the User Datagram Protocol (UDP). However, because 2.5G mobile networks supported the Transmission Control Protocol (TCP) but did not consistently support UDP, some implementations of ToIP over mobile networks use TCP internally. 3G mobile networks can support UDP.
The protocol stack for a ToIP medium is:
Very fast typing (30 characters per second) results in a two kilobit per second traffic load (including overheads for RFC 4103 with the maximum level of redundancy, RTP, UDP and IP).
Control of ToIP sessions has been defined using the standard Session Initiation Protocol (SIP) (RFC 3261) and the Session Description Protocol (SDP) (RFC 4566) protocols.
See IETF RFC 5194 "Framework for real-time text over IP using the Session Initiation Protocol (SIP)" and IETF RFC 4504 "SIP Telephony Device Requirements and Configuration" Section 2.9 for more information.
Next Generation Networking (NGNs) is a concept developed by telecommunication service providers and their suppliers. It aims to create a true multi-service network based in IP technology.
ToIP has been specified for inclusion in the 3GPP IP Multimedia Subsystem (IMS) (in 3GPP TS 26.114 v2.0.0 "IMS, Multimedia Telephony, Media handling and interaction"). IMS is being used to implement NGNs in many fixed and mobile networks.
Support of ToIP is being considered in multimedia Emergency Public-safety answering point (PSAPs) in Europe and USA. The ECRIT IETF working group defines ToIP as one form of access to Emergency Services.
ToIP can provide a 'low impact' solution to meeting national regulatory requirements to provide 'equivalent service' to the telephone service for people who have hearing or speech impairments.
A typical terminal on a fixed line access is a home computer that supports multimedia communications - Voice and Video and real-time Text over IP. See External links for information about ToIP equipment and software.
Telecommunications device for the deaf (TDD) or TTYs (also called Textphone or minicoms) were designed to transport real-time text over the PSTN . TDDs use a range of modem technologies.
Text-over-IP has been designed as a replacement for TDDs when using the IP-based networks but also to be of use to mainstream voice call users. It has less service restrictions compared with TDDs, is designed to be used as a mainstream service and can be used on standard computers or mobile terminals. Proper alerting systems for incoming calls need to be included as well as user interfaces, both hardware and software, that meet the needs of deaf people, and people with hearing or speech impairments. This can best be achieved with input from end-users in the development stages.
Interworking between TDDs and ToIP has been implemented using gateways by T-Meeting, Omnitor, Trace R& D, RNID, Center, Voiceriver, and AnnieS. RFC 5194 "Framework for real-time text over IP using the Session Initiation Protocol (SIP)" provides an overview of interworking issues. Work is being proposed in the IETF SIPPING work group on more detailed interworking based on a range of call scenarios. | https://en.wikipedia.org/wiki/Text_over_IP |
Text shaping is the process of converting text to glyph indices and positions as part of text rendering . [ 1 ] It is complementary to font rendering as part of the text rendering process; font rendering is used to generate the glyphs, and text shaping decides which glyphs to render and where they should be put on the image plane. [ 2 ] Unicode is generally used to specify the text to be rendered.
Text shaping results in substantially better results on Latin script; for some scripts with complex text layout such as Arabic script, text shaping is necessary for text to be readable at all. [ 3 ]
Most graphical user interface systems, including those in MacOS , iOS , [ 4 ] and Microsoft Windows have their own native text rendering engines that include text shaping. Microsoft 's Uniscribe framework permits the use of pluggable shaping engines. [ 5 ] Monotype 's WorldType system also provides shaping functions. [ 6 ]
In the open source world, HarfBuzz is a popular text shaping engine. According to HarfBuzz's developers, HarfBuzz is used by a range of software products including Android , Chrome , ChromeOS , Firefox , GNOME , GTK+ , KDE , Qt , LibreOffice , OpenJDK , XeTeX , PlayStation , Microsoft Edge , Adobe Photoshop , Illustrator , InDesign , and Godot Engine . [ 7 ]
Text shaping engines require descriptions of shaping properties and rules packaged in a format known as a shaping model. Shaping models include OpenType Layout , Graphite , and Apple Advanced Typography . [ 8 ]
This computing article is a stub . You can help Wikipedia by expanding it . | https://en.wikipedia.org/wiki/Text_shaping |
The Textile Research Journal is a peer-reviewed scientific journal that covers the field of materials science , especially as applying to textiles . The journal's editor is Dong Zhang. It was established in 1931 and is published by SAGE Publications .
The journal is abstracted and indexed in Scopus , and the Science Citation Index Expanded . According to the Journal Citation Reports , its 2020 impact factor is 1.820, ranking it 9th out of 25 journals in the category "Materials Science, Textiles". [ 1 ]
This article about a materials science journal is a stub . You can help Wikipedia by expanding it .
See tips for writing articles about academic journals . Further suggestions might be found on the article's talk page . | https://en.wikipedia.org/wiki/Textile_Research_Journal |
Textile manufacturing or textile engineering is a major industry . It is largely based on the conversion of fibre into yarn , then yarn into fabric. These are then dyed or printed, fabricated into cloth which is then converted into useful goods such as clothing , household items, upholstery and various industrial products. [ 1 ]
Different types of fibres are used to produce yarn. Cotton remains the most widely used and common natural fiber making up 90% of all-natural fibers used in the textile industry. People often use cotton clothing and accessories because of comfort, not limited to different weathers. There are many variable processes available at the spinning and fabric-forming stages coupled with the complexities of the finishing and colouration processes to the production of a wide range of products.
Textile manufacturing in the modern era is an evolved form of the art and craft industries. Until the 18th and 19th centuries, the textile industry was a household work. It became mechanised in the 18th and 19th centuries, and has continued to develop through science and technology since the twentieth century. [ 2 ] Specifically, ancient civilizations in India, Egypt, China, sub-Saharan Africa, Eurasia, South America, and North and East Africa all had some forms of textile production. The first book about textile manufacturing is considered to be 'A Treatise on the Art of Weaving' by John Murphy. [ 3 ]
Cotton is the world's most important natural fibre. In the year 2007, the global yield was 25 million tons from 35 million hectares cultivated in more than 50 countries. [ 4 ]
There are six stages to the manufacturing of cotton textiles: [ 5 ]
Cotton is grown in locations with long, hot, dry summers with plenty of sunshine and low humidity. Indian cotton, Gossypium arboreum , is finer but the staple is only suitable for hand processing. American cotton, Gossypium hirsutum , produces the longer staple needed for mechanised textile production. [ 6 ] The planting season is from September to mid-November, and the crop is harvested between March and June. The cotton bolls are harvested by stripper harvesters and spindle pickers that remove the entire boll from the plant. The cotton boll is the seed pod of the cotton plant; attached to each of the thousands of seeds are fibres about 2.5 cm long. [ 7 ] There is a higher rate of cotton being produced compared to the actual workers needed to produce the material. In 2013 a cotton farmer in Mississippi, Bower Flowers, produced around 13,000 bales of cotton in that year alone. This amount of cotton could be used to produce up to 9.4 million T-shirts. [ 8 ]
The seed cotton goes into a cotton gin . The cotton gin separates seeds and removes the "trash" (dirt, stems and leaves) from the fibre. In a saw gin, circular saws grab the fibre and pull it through a grating that is too narrow for the seeds to pass. A roller gin is used with longer-staple cotton. Here, a leather roller captures the cotton. A knife blade, set close to the roller, detaches the seeds by drawing them through teeth in circular saws and revolving brushes which clean them away. [ 9 ] The ginned cotton fibre, known as lint, is then compressed into bales which are about 1.5 m tall and weigh almost 220 kg. Only 33% of the crop is usable lint. Commercial cotton is graded and priced according to its quality; this broadly relates to the average length of the staple and the variety of the plant. Longer-staple cotton (2½ in to 1¼ in) is called Egyptian, medium staple (1¼ in to ¾ in) is called American upland, and short staple (less than ¾ in) is called Indian. [ 10 ] The cotton seed is pressed into cooking oil. The husks and meal are processed into animal feed, and the stems into paper.
Ginning, bale-making and transportation are done in the country of origin.
Cotton is shipped to mills in large 500-pound bales. When the cotton comes out of a bale, it is all packed together and still contains vegetable matter. The bale is broken open using a machine with large spikes, called an opener . To fluff up the cotton and remove the vegetable matter, the cotton is sent through a picker or a similar machine. In a picker , the cotton is beaten with a beater bar to loosen it up. It is then fed through various rollers, which serve to remove the vegetable matter. The cotton, aided by fans, then collects on a screen and gets fed through more rollers where it emerges as a continuous soft fleecy sheet, known as a lap. [ 10 ] [ 11 ]
Scutching refers to the process of cleaning cotton of its seeds and other impurities. The first scutching machine was invented in 1797, but did not come into further mainstream use until after 1808 or 1809, when it was introduced and used in Manchester, England. By 1816, it had become generally adopted. The scutching machine worked by passing the cotton through a pair of rollers, and then striking it with iron or steel bars called beater bars or beaters. The beaters, which turn very quickly, strike the cotton hard and knock the seeds out. This process is done over a series of parallel bars so as to allow the seeds to fall through. At the same time, air is blown across the bars, which carries the cotton into a cotton chamber.
In the carding process, the fibres are separated and then assembled into a loose strand (sliver or tow). The cotton comes off of the picking machine in laps, and is then taken to carding machines. The carders line up the fibres neatly to make them easier to spin. The carding machine consists mainly of one big roller with smaller ones surrounding it. All of the rollers are covered in small teeth, and as the cotton is moved forwards, the teeth get finer (i.e. closer together). The cotton leaves the carding machine in the form of a sliver: a large rope of fibres. [ 12 ] In a wider sense, carding can refer to these four processes:
Combing is optional, but is used to remove the shorter fibres, creating a stronger yarn. [ 13 ]
Several slivers are combined. Each sliver will have thin and thick spots, and by combining several slivers together, a more consistent size can be reached. Since combining several slivers produces a very thick rope of cotton fibres, the slivers are separated into rovings. Generally speaking, for machine processing, a roving is about the width of a pencil. These rovings (or slubbings) are then what are used in the spinning process. [ 14 ]
Most spinning today is done using break, or open-end spinning . This is a technique where the fibres are blown by air into a rotating drum, where they attach themselves to the tail of formed yarn that is continually being drawn out of the chamber. Other methods of break spinning use needles and electrostatic forces. [ 15 ] This method has replaced the older methods of ring and mule spinning. It is also easily adapted for artificial fibres .
The spinning machines takes the roving, thins it and twists it, creating yarn which it winds onto a bobbin. [ 16 ]
In mule spinning the roving is pulled off a bobbin and fed through rollers, which are feeding at several different speeds. This thins the roving at a consistent rate. If the roving was not a consistent size, then this step could cause a break in the yarn, or jam the machine. The yarn is twisted through the spinning of the bobbin as the carriage moves out, and is rolled onto a cylinder called a spindle, which then produces a cone-shaped bundle of fibres known as a "cop", as the carriage returns. Mule spinning produces a finer thread than ring spinning . [ 17 ]
The mule was an intermittent process, as the frame advanced and returned a distance of five feet. It was the descendant of the 1779 Crompton device. It produces a softer, less twisted thread that was favoured for fine fabrics and wefts.
The ring was a descendant of the Arkwright Water frame of 1769. It was a continuous process, the yarn was coarser, had a greater twist and was stronger, thus suitable for use as warp thread. Ring spinning is slow due to the distance the thread must pass around the ring.
Sewing thread was made of several threads twisted together, or doubled.
This is the process where each of the bobbins is rewound to give a tighter bobbin.
Plying is done by pulling yarn from two or more bobbins and twisting it together, in a direction opposite to the one it was spun in. Depending on the weight desired, the cotton may or may not be plied, and the number of strands twisted together varies. [ 18 ]
Gassing is the process of passing yarn very rapidly through a series of Bunsen gas flames in a gassing frame, to burn off the projecting fibres and to make the thread round and smooth and bright. Only the better qualities of yarn are gassed, like the kinds used for voiles, poplins, venetians, gabardines, Egyptian cottons, etc. The thread loses around 5-8% of its weight if it's gassed. The gassed yarn is darker in shade afterwards, but should not be scorched. [ 19 ]
The weaving process uses a loom . The lengthwise threads are known as the warp , and the crosswise threads are known as the weft . The warp, which must be strong, needs to be presented to loom on a warp beam. The weft passes across the loom in a shuttle that carries the yarn on a pirn . These pirns are automatically changed by the loom. Thus, the yarn needs to be wrapped onto a beam, and onto pirns before weaving can commence. [ 23 ]
After being spun and plied, the cotton thread is taken to a warping room where the winding machine takes the required length of yarn and winds it onto warpers' bobbins.
Racks of bobbins are set up to hold the thread while it is wound onto the warp beam of a loom. Because the thread is fine, often three of these would be combined to get the desired number of ends. [ 24 ]
A sizing machine is needed for strengthening the warp by adding starch, to reduce breakage.
The process of drawing each end of the warp separately through the dents of the reed and the eyes of the healds, in the order indicated by the draft.
A pirn-winding frame was used to transfer the weft from cheeses of yarn onto the pirns that would fit into the shuttle.
At this point, the thread is woven. Depending on the era, one person could manage anywhere from 3 to 100 machines. In the mid-nineteenth century, four was the standard number. A skilled weaver in 1925 could run 6 Lancashire Looms . As time progressed, new mechanisms were added that stopped the loom any time something went wrong. The mechanisms checked for such things as broken warp or weft threads, the shuttle going straight across, and if the shuttle was empty. Forty of these Northrop Looms or automatic looms could be operated by one skilled worker. [ 25 ]
The three primary movements of a loom are shedding, picking, and beating-up.
The Lancashire Loom was the first semi-automatic loom. Jacquard looms and Dobby looms are looms that have sophisticated methods of shedding. They may be separate looms or mechanisms added to a plain loom. A Northrop Loom was fully automatic and was mass-produced between 1909 and the mid-1960s. Modern looms run faster and do not use a shuttle: there are air jet looms, water jet looms, and rapier looms .
Ends and Picks: Picks refer to the weft, ends refer to the warp. The coarseness of the cloth can be expressed as the number of picks and ends per quarter-inch square, or per inch square. Ends is always written first. For example: Heavy domestics are made from coarse yarns, such as 10's to 14's warp and weft, and about 48 ends and 52 picks. [ 27 ]
Associated job titles include piecer, scavenger , weaver, tackler , draw boy.
When a hand loom was located in the home, children helped with the weaving process from an early age. Piecing needs dexterity, and a child can be as productive as an adult. When weaving moved from the home to the mill, children were often allowed to help their older sisters, and laws had to be made to prevent child labour from becoming established. The working conditions of cotton production were often harsh, with long hours, low pay, and dangerous machinery. Children, above all, were also prone to physical abuse and often forced to work in unsanitary conditions. It should also be noted that children who worked in handlooms often faced extreme poverty and were unable to obtain an education. The working conditions of cotton production were often harsh, with long hours, low pay, and dangerous machinery. unable to obtain an education.
Knitting by machine is done in two different ways; warp and weft. Weft knitting (as seen in the pictures) is similar in method to hand knitting with stitches all connected to each other horizontally. Various weft machines can be configured to produce textiles from a single spool of yarn or multiple spools, depending on the size of the machine cylinder (in which the needles are bedded). In a warp knit , there are many pieces of yarn and there are vertical chains, zigzagged together by crossing the cotton yarn.
Warp knits do not stretch as much as a weft knits, and they are run-resistant. A weft knit is not run-resistant, but it has more stretch. This is especially true if spools of elastane are processed from separate spool containers and interwoven through the cylinder with cotton yarn, giving the finished product more flexibility and preventing it from having a 'baggy' appearance. The average t-shirt is a weft knit. [ 28 ]
Finishing is a broad range of physical and chemical processes/treatments that complete one stage of textile manufacturing, sometimes in preparation for the next step. Finishing adds value to the product and makes it more attractive, useful and functional for the end-user. [ 29 ] Fresh off the loom, cotton fabric not only contains impurities, including warp size, but it also requires further treatment to develop its full potential and to add to its value. [ 30 ] [ 31 ]
Depending on the size that has been used, the cloth may be steeped in a dilute acid and then rinsed, or enzymes may be used to break down the size. [ 32 ]
Scouring is a chemical washing process carried out on cotton fabric to remove natural waxes and non-fibrous impurities (like the remains of seed fragments) from the fibres and any soiling or dirt that might remain. Scouring is usually carried out in iron vessels called kiers . The fabric is boiled in an alkali solution, which forms a soap with free fatty acids. A kier is usually enclosed, so the solution of sodium hydroxide can be boiled under pressure, excluding oxygen , which would degrade the cellulose in the fibre. If the appropriate reagents are used, scouring will also remove size from the fabric, although desizing often precedes scouring and is considered to be a separate process. Preparation and scouring are prerequisites to most of the other finishing processes. At this stage, even the most naturally white cotton fibres are yellowish, and bleaching is required. [ 32 ]
Bleaching improves whiteness by removing natural colouration and whatever impurities remain in the cotton; the degree of bleaching is determined by the levels of whiteness and absorbency required of the fabric. Cotton, being a vegetable fibre, is bleached using an oxidizing agent , such as diluted sodium hypochlorite or diluted hydrogen peroxide . If the fabric is to be dyed a deep shade, then lower levels of bleaching are acceptable. However, for white bedding and for medical applications, the highest levels of whiteness and absorbency are essential. [ 33 ]
A further possibility is mercerising, during which the fabric is treated with a caustic soda solution, to cause swelling of the fibres. This results in improved lustre, strength and dye affinity. Cotton is mercerised under tension, and all alkali must be washed out before the tension is released, or shrinkage will take place. [ 34 ]
Many other chemical treatments may be applied to cotton fabrics to produce low flammability, crease-resistance and other qualities, but the four most important non-chemical finishing treatments are:
Singeing is designed to burn off the surface fibres from the fabric to produce smoothness. The fabric passes over brushes to raise the fibres, then passes over a plate heated by gas flames.
During raising, the fabric surface is treated with sharp teeth to lift the surface fibres, thereby imparting downiness, softness and warmth, as in flannelette.
Calendering is a process in which the fabric is passed between heated rollers to generate smooth, polished or embossed effects.
Sanforisation is a form of mechanical pre-shrinking, so that the fabric will shrink less upon laundering.
Dyeing is commonly carried out with an anionic direct dye by completely immersing the fabric (or yarn) in an aqueous dye bath according to a prescribed procedure. For improved fastness to washing, rubbing and light, further dyeing methods can be used. These require more complex chemistry during processing, and are thus more expensive to apply.
Printing is the application of colour in the form of a paste or ink to the surface of a fabric in a predetermined pattern. It can be described as a form of localised dyeing. Printing designs onto previously dyed fabric is also possible.
Production of cotton requires arable land .
In addition, cotton is farmed intensively and uses large amounts of fertilizer and 25% of the world's insecticides. Native Indian varieties of cotton were rainwater fed, but modern hybrids used for the mills need irrigation, which spreads pests. The 5% of cotton-bearing land in India uses 55% of all pesticides used in India. [ 6 ]
The consumption of energy in form of water and electricity is relatively high, especially in processes like washing, de-sizing, bleaching, rinsing, dyeing, printing, coating and finishing. Processing is time-consuming. The major portion of water in textile industry is used for wet processing of textile (70 per cent). Approximately 25 per cent of energy in the total textile production like fibre production, spinning, twisting, weaving, knitting, clothing manufacturing etc. is used in dyeing. About 34 per cent of energy is consumed in spinning, 23 per cent in weaving, 38 per cent in chemical wet processing and five per cent in miscellaneous processes. Power dominates consumption pattern in spinning and weaving, while thermal energy is the major factor for chemical wet processing. [ 4 ]
Cotton acts as a carbon sink as it contains cellulose and this contains 44.44% carbon. However, due to carbon emissions from fertiliser application, use of mechanized tools to harvest the cotton and so forth cotton manufacture tends to emit more CO 2 than is stored in the form of cellulose. [ 35 ]
The growth of cotton is divided into two segments i.e. organic and genetically modified . [ 4 ] Cotton crop provides livelihood to millions of people but its production is becoming expensive because of high water consumption, use of expensive pesticides, insecticides and fertiliser. Genetically modified products aim to increase disease resistance and reduce the water required. The organic sector in India was worth $583 million. Genetically modified cotton, in 2007, occupied 43% of cotton growing areas in India. [ 6 ]
Before mechanisation, cotton was harvested manually by farmers in India and by African slaves in America. In 2012 Uzbekistan was a major exporter of cotton and uses manual labour during the harvest. Human rights groups have expressed concerns over healthcare professionals and children being forced to pick cotton. [ 36 ]
There was a 1.5 million tonne cotton deficit in 2018 due to adverse weather conditions, limited water, and pest issues. [ 37 ]
Flax is a bast fibre , which means it comes in bundles under the bark of the Linum usitatissimum plant. The plant flowers and is harvested. It is subjected to retting , breaking, scutching , hackling or combing. It is then treated like cotton. [ 38 ]
Jute is a bast fibre , which comes from the inner bark of the plants of the Corchorus genus. It is retted like flax, sundried and baled. When spinning a small amount of oil must be added to the fibre. It can be bleached and dyed. It was used for sacks and bags but is now used for the backing for carpets. [ 39 ] Jute can be blended with other fibres to make composite fabrics and work continues in Bangladesh to refine the processes and extend the range of usage possible. In the 1970s, jute-cotton composite fabrics were known as jutton fabrics. [ 40 ]
Hemp is a bast fibre from the inner bark of Cannabis sativa . It is difficult to bleach, and is used for making cord and rope. It is subject to retting , separating and pounding [ 41 ]
These bast fibres can also be used: kenaf , urena , ramie , nettle .
Sisal is the main leaf fibre used; others are abacá and henequen .
Wool comes from domesticated sheep. It is used to create two kinds of yarn, woolens and worsteds . These are distinguished by the direction of the wool fibres in relation to the thread; woolens are perpendicularly arranged, allowing for fluffy yarns that trap air, while worsteds have parallel fibres, creating a strong and smooth yarn.
Modern sheep have uniform fleeces, while primitive and landrace sheep often have dual coats; a soft, short under layer and a hardier, coarser, and longer guard layer. These can be sorted to be processed separately, or spun together. The differing characteristics of each coat allows for very different yarn; the guard hairs can be used for durable outerwear, while the inner coat is what is traditionally used to produce the ultrafine wedding ring shawls across Europe. [ 42 ] Spinning them together, like in lopi , produces a unique yarn that combines the strength of the guard hairs with the loft and softness of the undercoat.
Wool that has never been used is known as virgin wool and can be mixed with wool that has been recovered from rags. "Shoddy" is the term for recovered wool that is not matted, while "mungo" comes from felted wool. Extract is recovered chemically from mixed cotton/wool fabrics.
The fleece is shorn in one piece from the sheep. Ideally, the wool is cut as close to the skin as possible to maximise fibre length. Going over the same spot twice produces small fibres that will produce pills in finished fabric, something that skilled shearers are usually able to avoid. This is then skirted to remove the soiled wool from around the legs and anus, graded, and baled. Grading is done on quality as well as length of the fibres. Long wool fibres can be up to 15 in, but anything over 2.5 inches is suitable for combing into worsteds. Fibres less than that form short wool and are described as clothing or carding wool, and are best suited for the jumbled arrangement of woolens.
At the mill the wool is scoured in a detergent to remove grease (the yolk) and impurities. This is done mechanically in the opening machine. Vegetable matter can be removed chemically using sulphuric acid (carbonising). Washing uses a solution of soap and sodium carbonate . The wool is oiled before carding or combing.
The processes in silk production are similar to those of cotton but take account that reeled silk is a continuous fibre. The terms used are different.
Both wool and silk require farmland . Whereas silkworms require mulberry leaves, sheep eat grass, clover, forbs and other pasture plants. Sheep, like all ruminants emit CO 2 via their digestive system. [ 44 ] Also, their pastures may sometimes be fertilised which further increases emissions. [ 45 ]
Synthetic fibres are the result of extensive development by scientists to improve upon the naturally occurring animal and plant fibres. In general, synthetic fibres are created by forcing, or extruding , fibre forming materials through holes (called spinnerets) into the air, thus forming a thread. Before synthetic fibres were developed, cellulose fibres were made from natural cellulose , which comes from plants.
The first artificial fibre, known as art silk from 1799 onwards, became known as viscose around 1894, and finally rayon in 1924. A similar product known as cellulose acetate was discovered in 1865. Rayon and acetate are both artificial fibres, but not truly synthetic, being made from wood. Although these artificial fibres were discovered in the mid-nineteenth century, successful modern manufacture began much later in the 1930s. Nylon, the first synthetic fibre, made its debut in the United States as a replacement for silk, and was used for parachutes and other military uses. [ citation needed ]
The techniques used to process these fibres in yarn are essentially the same as with natural fibres, modifications have to be made as these fibres are of great length, and have no texture such as the scales in cotton and wool that aid meshing. [ citation needed ]
Unlike natural fibres, produced by plants, animals or insects, synthetic fibres are made from fossil fuels , and thus require no farmland. [ 46 ]
Media related to Textile manufacturing at Wikimedia Commons | https://en.wikipedia.org/wiki/Textile_manufacturing |
Textual case-based reasoning (TCBR) is a subtopic of case-based reasoning , in short CBR, a popular area in artificial intelligence . CBR suggests the ways to use past experiences to solve future similar problems, requiring that past experiences be structured in a form similar to attribute-value pairs . This leads to the investigation of textual descriptions for knowledge exploration whose output will be, in turn, used to solve similar problems. [ 1 ]
Textual case-base reasoning research has focused on:
This artificial intelligence -related article is a stub . You can help Wikipedia by expanding it . | https://en.wikipedia.org/wiki/Textual_case-based_reasoning |
Texture compression is a specialized form of image compression designed for storing texture maps in 3D computer graphics rendering systems. Unlike conventional image compression algorithms, texture compression algorithms are optimized for random access .
Texture compression can be applied to reduce memory usage at runtime. Texture data is often the largest source of memory usage in a mobile application.
In their seminal paper on texture compression, [ 1 ] Beers, Agrawala and Chaddha list four features that tend to differentiate texture compression from other image compression techniques. These features are:
Given the above, most texture compression algorithms involve some form of fixed-rate lossy vector quantization of small fixed-size blocks of pixels into small fixed-size blocks of coding bits, sometimes with additional extra pre-processing and post-processing steps. Block Truncation Coding is a very simple example of this family of algorithms.
Because their data access patterns are well-defined, texture decompression may be executed on-the-fly during rendering as part of the overall graphics pipeline , reducing overall bandwidth and storage needs throughout the graphics system. As well as texture maps, texture compression may also be used to encode other kinds of rendering map, including bump maps and surface normal maps . Texture compression may also be used together with other forms of map processing such as MIP maps and anisotropic filtering .
Some examples of practical texture compression systems are S3 Texture Compression (S3TC), PVRTC , Ericsson Texture Compression (ETC) and Adaptive Scalable Texture Compression (ASTC); these may be supported by special function units in modern Graphics processing units .
OpenGL and OpenGL ES, as implemented on many video accelerator cards and mobile GPUs, can support multiple common kinds of texture compression - generally through the use of vendor extensions.
A compressed-texture can be further compressed in what is called "supercompression". Fixed-rate texture compression formats are optimized for random access and are much less efficient compared to image formats such as PNG . By adding further compression, a programmer can reduce the efficiency gap. The extra layer can be decompressed by the CPU so that the GPU receives a normal compressed texture, [ 3 ] or in newer methods, decompressed by the GPU itself. Supercompression saves the same amount of VRAM as regular texture compression, but saves more disk space and download size. [ 4 ]
Random-Access Neural Compression of Material Textures (Neural Texture Compression) is a Nvidia 's technology which enables two additional levels of detail (16x more texels , so four times higher resolution) while maintaining similar storage requirements as traditional texture compression methods. [ 5 ]
The key idea is compressing multiple material textures and their mipmap chains together, and using a small neural network , that is optimized for each material, to decompress them. [ 6 ] | https://en.wikipedia.org/wiki/Texture_compression |
In computer graphics , a texture mapping unit ( TMU ) is a component in modern graphics processing units (GPUs). They are able to rotate, resize , and distort a bitmap image to be placed onto an arbitrary plane of a given 3D model as a texture, in a process called texture mapping . In modern graphics cards it is implemented as a discrete stage in a graphics pipeline , [ 1 ] whereas when first introduced it was implemented as a separate processor, e.g. as seen on the Voodoo2 graphics card.
The TMU came about due to the compute demands of sampling and transforming a flat image (as the texture map) to the correct angle and perspective it would need to be in 3D space. The compute operation is a large matrix multiply , which CPUs of the time (early Pentiums for example) could not cope with at an acceptable level of performance.
In 2013, TMUs are part of the shader pipeline and decoupled from the Render Output Pipelines (ROPs). For example, in AMD's Cypress GPU, each shader pipeline (of which there are 20) has four TMUs, giving the GPU 80 TMUs. This is done by chip designers to closely couple shaders and the texture engines they will be working with.
3D scenes are generally composed of two things: 3D geometry , and the textures that cover that geometry. Texture units in a video card take a texture and 'map' it to a piece of geometry. That is, they wrap the texture around the geometry and produce textured pixels which can then be written to the screen.
Textures can be an actual image, a lightmap , or even normal maps for advanced surface lighting effects.
To render a 3D scene, textures are mapped over the top of polygon meshes . This is called texture mapping and is accomplished by texture mapping units (TMUs) on the videocard. Texture fill rate is a measure of the speed with which a particular card can perform texture mapping.
Though pixel shader processing is becoming more important, this number still holds some weight. Best example of this is the X1600 XT. This card has a 3 to 1 ratio of pixel shader processors/texture mapping units. As a result, the X1600 XT achieves lower performance when compared to other GPUs of the same era and class (such as nVidia's 7600GT) [ citation needed ] . In the mid range, texture mapping can still very much be a bottleneck.
However, at the high end, the X1900 XTX has this same 3 to 1 ratio, but does just fine because screen resolutions top out and it has more than enough texture mapping power to handle any display.
Textures need to be addressed and filtered. This job is done by TMUs that work in conjunction with pixel and vertex shader units. It is the TMU's job to apply texture operations to pixels. The number of texture units in a graphics processor is used when comparing two different cards for texturing performance. It is reasonable to assume that the card with more TMUs will be faster at processing texture information.
In modern GPUs TMUs contain Texture Address Units(TA) and Texture Filtering Units(TF). Texture Address Units map texels to pixels and can perform texture addressing modes. Texture Filtering Units optionally perform hardware based texture filtering .
A pipeline is the graphics card's architecture, which provides a generally accurate idea of the computing power of a graphics processor.
A pipeline isn't formally accepted as a technical term. There are different pipelines within a graphics processor as there are separate functions being performed at any given time. Historically, it has been referred to as a pixel processor that is attached to a dedicated TMU. A Geforce 3 had four pixel pipelines, each of which had two TMUs. The rest of the pipeline handled things like depth and blending operations.
The ATI Radeon 9700 was first to break this mould, by placing a number of vertex shader engines independent of the pixel shaders. The R300 GPU used in the Radeon 9700 had four global vertex shaders, but split the rest of the rendering pipeline in half (it was, so to speak, dual core) each half, called a quad, had four pixel shaders, four TMUs and four ROPs.
Some units are used more than others, and in an effort to increase the processor's entire performance, they attempted to find a "sweet spot" in the number of units needed for optimum efficiency without the need for excess silicon. In this architecture the name pixel pipeline lost its meaning as pixel processors were no longer attached to single TMUs.
The vertex shader had long been decoupled, starting with the R300, but the pixel shader was not so easily done, as it required colour data (e.g. texture samples) to work with, and hence needed to be closely coupled to a TMU.
Said coupling remains to this day, where the shader engine, made of units able to run either vertex or pixel data, is tightly coupled to a TMU but has a crossbar dispatcher between its output and the bank of ROPs.
The Render Output Pipeline is an inherited term, and more often referred to as the render output unit . Its job is to control the sampling of pixels (each pixel is a dimensionless point), so it controls antialiasing , when more than one sample is merged into one pixel. All data rendered has to travel through the ROP in order to be written to the framebuffer , from there it can be transmitted to the display.
Therefore, the ROP is where the GPU's output is assembled into a bitmapped image ready for display.
In GPGPU , texture maps in 1, 2, or 3 dimensions may be used to store arbitrary data. By providing interpolation , the texture mapping unit provides a convenient means of approximating arbitrary functions with data tables. | https://en.wikipedia.org/wiki/Texture_mapping_unit |
Bistriflimide , also known variously as bis(trifluoromethane)sulfonimide , bis(trifluoromethanesulfonyl)imide , bis(trifluoromethanesulfonyl)imidate (and variations thereof), informally and somewhat inaccurately as triflimide or triflimidate , or by the abbreviations TFSI or NTf 2 , is a non-coordinating anion with the chemical formula [( C F 3 S O 2 ) 2 N ] − . Its salts are typically referred to as being metal triflimidates .
The anion is widely used in ionic liquids (such as trioctylmethylammonium bis(trifluoromethylsulfonyl)imide ), since it is less toxic and more stable than more "traditional" counterions such as tetrafluoroborate . This anion is also of importance in lithium-ion and lithium metal batteries ( LiTFSI ) because of its high dissociation and conductivity. It has the added advantage of suppressing crystallinity in poly(ethylene oxide), which increases the conductivity of that polymer below its melting point at 50 °C.
The conjugate acid of bistriflimide, which is frequently referred to by the trivial name bistriflimidic acid (CAS: 82113-65-3), is a commercially available superacid . It is a crystalline compound, but is hygroscopic to the point of being deliquescent . Owing to its very high acidity and good compatibility with organic solvents it has been employed as a catalyst in a wide range of chemical reactions. [ 1 ]
Its p K a value in water cannot be accurately determined but in acetonitrile it has been estimated as −0.10 and in 1,2-dichloroethane −12.3 (relative to the p K a value of 2,4,6-trinitrophenol ( picric acid ), anchored to zero to crudely approximate the aqueous p K a scale [ 2 ] ), making it more acidic than triflic acid (p K a MeCN = 0.70, p K a DCE (relative to picric acid ) = −11.4). [ 3 ]
Developing an IUPAC name for bistriflimide that indicates the structure and reactivity is challenging, and changes to current names have been proposed. The main difficulty arises from the ambiguous use of the word amide to mean an acylated (including sulfonylated) amine or the anionic form of an amine. Likewise, imide can refer to a bisacylated amine or a twice deprotonated amine . Thus, depending on the system used, there is ambiguity as to whether amide or imide is being used to refer to the parent acid or the anion. (The anion has been referred to as an amidate or imidate in an attempt to distinguish it from the acid.) The complications in naming these compounds was highlighted in an article by the IUPAC. [ 4 ] Since then, the IUPAC has recommended (2013) that derivatives of anionic nitrogen can be named as azanides , so bis(trifluoromethanesulfonyl)azanide would be an acceptable and unambiguous name for the bistriflimide anion. The parent acid, whose trivial name is triflimidic acid, would then be called bis(trifluoromethanesulfonyl)azane. [ 5 ]
The name 1,1,1-trifluoro- N -((trifluoromethyl)sulfonyl)methanesulfonamide is also an unambiguous IUPAC-acceptable name, though the symmetry of the molecule is not apparent from this construction. | https://en.wikipedia.org/wiki/Tf2NH |
Bistriflimide , also known variously as bis(trifluoromethane)sulfonimide , bis(trifluoromethanesulfonyl)imide , bis(trifluoromethanesulfonyl)imidate (and variations thereof), informally and somewhat inaccurately as triflimide or triflimidate , or by the abbreviations TFSI or NTf 2 , is a non-coordinating anion with the chemical formula [( C F 3 S O 2 ) 2 N ] − . Its salts are typically referred to as being metal triflimidates .
The anion is widely used in ionic liquids (such as trioctylmethylammonium bis(trifluoromethylsulfonyl)imide ), since it is less toxic and more stable than more "traditional" counterions such as tetrafluoroborate . This anion is also of importance in lithium-ion and lithium metal batteries ( LiTFSI ) because of its high dissociation and conductivity. It has the added advantage of suppressing crystallinity in poly(ethylene oxide), which increases the conductivity of that polymer below its melting point at 50 °C.
The conjugate acid of bistriflimide, which is frequently referred to by the trivial name bistriflimidic acid (CAS: 82113-65-3), is a commercially available superacid . It is a crystalline compound, but is hygroscopic to the point of being deliquescent . Owing to its very high acidity and good compatibility with organic solvents it has been employed as a catalyst in a wide range of chemical reactions. [ 1 ]
Its p K a value in water cannot be accurately determined but in acetonitrile it has been estimated as −0.10 and in 1,2-dichloroethane −12.3 (relative to the p K a value of 2,4,6-trinitrophenol ( picric acid ), anchored to zero to crudely approximate the aqueous p K a scale [ 2 ] ), making it more acidic than triflic acid (p K a MeCN = 0.70, p K a DCE (relative to picric acid ) = −11.4). [ 3 ]
Developing an IUPAC name for bistriflimide that indicates the structure and reactivity is challenging, and changes to current names have been proposed. The main difficulty arises from the ambiguous use of the word amide to mean an acylated (including sulfonylated) amine or the anionic form of an amine. Likewise, imide can refer to a bisacylated amine or a twice deprotonated amine . Thus, depending on the system used, there is ambiguity as to whether amide or imide is being used to refer to the parent acid or the anion. (The anion has been referred to as an amidate or imidate in an attempt to distinguish it from the acid.) The complications in naming these compounds was highlighted in an article by the IUPAC. [ 4 ] Since then, the IUPAC has recommended (2013) that derivatives of anionic nitrogen can be named as azanides , so bis(trifluoromethanesulfonyl)azanide would be an acceptable and unambiguous name for the bistriflimide anion. The parent acid, whose trivial name is triflimidic acid, would then be called bis(trifluoromethanesulfonyl)azane. [ 5 ]
The name 1,1,1-trifluoro- N -((trifluoromethyl)sulfonyl)methanesulfonamide is also an unambiguous IUPAC-acceptable name, though the symmetry of the molecule is not apparent from this construction. | https://en.wikipedia.org/wiki/Tf2N− |
In mathematics , the trigonometric functions (also called circular functions , angle functions or goniometric functions ) [ 1 ] are real functions which relate an angle of a right-angled triangle to ratios of two side lengths. They are widely used in all sciences that are related to geometry , such as navigation , solid mechanics , celestial mechanics , geodesy , and many others. They are among the simplest periodic functions , and as such are also widely used for studying periodic phenomena through Fourier analysis .
The trigonometric functions most widely used in modern mathematics are the sine , the cosine , and the tangent functions. Their reciprocals are respectively the cosecant , the secant , and the cotangent functions, which are less used. Each of these six trigonometric functions has a corresponding inverse function , and an analog among the hyperbolic functions .
The oldest definitions of trigonometric functions, related to right-angle triangles, define them only for acute angles . To extend the sine and cosine functions to functions whose domain is the whole real line , geometrical definitions using the standard unit circle (i.e., a circle with radius 1 unit) are often used; then the domain of the other functions is the real line with some isolated points removed. Modern definitions express trigonometric functions as infinite series or as solutions of differential equations . This allows extending the domain of sine and cosine functions to the whole complex plane , and the domain of the other trigonometric functions to the complex plane with some isolated points removed.
Conventionally, an abbreviation of each trigonometric function's name is used as its symbol in formulas. Today, the most common versions of these abbreviations are " sin " for sine, " cos " for cosine, " tan " or " tg " for tangent, " sec " for secant, " csc " or " cosec " for cosecant, and " cot " or " ctg " for cotangent. Historically, these abbreviations were first used in prose sentences to indicate particular line segments or their lengths related to an arc of an arbitrary circle, and later to indicate ratios of lengths, but as the function concept developed in the 17th–18th century, they began to be considered as functions of real-number-valued angle measures, and written with functional notation , for example sin( x ) . Parentheses are still often omitted to reduce clutter, but are sometimes necessary; for example the expression sin x + y {\displaystyle \sin x+y} would typically be interpreted to mean ( sin x ) + y , {\displaystyle (\sin x)+y,} so parentheses are required to express sin ( x + y ) . {\displaystyle \sin(x+y).}
A positive integer appearing as a superscript after the symbol of the function denotes exponentiation , not function composition . For example sin 2 x {\displaystyle \sin ^{2}x} and sin 2 ( x ) {\displaystyle \sin ^{2}(x)} denote ( sin x ) 2 , {\displaystyle (\sin x)^{2},} not sin ( sin x ) . {\displaystyle \sin(\sin x).} This differs from the (historically later) general functional notation in which f 2 ( x ) = ( f ∘ f ) ( x ) = f ( f ( x ) ) . {\displaystyle f^{2}(x)=(f\circ f)(x)=f(f(x)).}
In contrast, the superscript − 1 {\displaystyle -1} is commonly used to denote the inverse function , not the reciprocal . For example sin − 1 x {\displaystyle \sin ^{-1}x} and sin − 1 ( x ) {\displaystyle \sin ^{-1}(x)} denote the inverse trigonometric function alternatively written arcsin x . {\displaystyle \arcsin x\,.} The equation θ = sin − 1 x {\displaystyle \theta =\sin ^{-1}x} implies sin θ = x , {\displaystyle \sin \theta =x,} not θ ⋅ sin x = 1. {\displaystyle \theta \cdot \sin x=1.} In this case, the superscript could be considered as denoting a composed or iterated function , but negative superscripts other than − 1 {\displaystyle {-1}} are not in common use.
If the acute angle θ is given, then any right triangles that have an angle of θ are similar to each other. This means that the ratio of any two side lengths depends only on θ . Thus these six ratios define six functions of θ , which are the trigonometric functions. In the following definitions, the hypotenuse is the length of the side opposite the right angle, opposite represents the side opposite the given angle θ , and adjacent represents the side between the angle θ and the right angle. [ 2 ] [ 3 ]
Various mnemonics can be used to remember these definitions.
In a right-angled triangle, the sum of the two acute angles is a right angle, that is, 90° or π / 2 radians . Therefore sin ( θ ) {\displaystyle \sin(\theta )} and cos ( 90 ∘ − θ ) {\displaystyle \cos(90^{\circ }-\theta )} represent the same ratio, and thus are equal. This identity and analogous relationships between the other trigonometric functions are summarized in the following table.
In geometric applications, the argument of a trigonometric function is generally the measure of an angle . For this purpose, any angular unit is convenient. One common unit is degrees , in which a right angle is 90° and a complete turn is 360° (particularly in elementary mathematics ).
However, in calculus and mathematical analysis , the trigonometric functions are generally regarded more abstractly as functions of real or complex numbers , rather than angles. In fact, the functions sin and cos can be defined for all complex numbers in terms of the exponential function , via power series, [ 5 ] or as solutions to differential equations given particular initial values [ 6 ] ( see below ), without reference to any geometric notions. The other four trigonometric functions ( tan , cot , sec , csc ) can be defined as quotients and reciprocals of sin and cos , except where zero occurs in the denominator. It can be proved, for real arguments, that these definitions coincide with elementary geometric definitions if the argument is regarded as an angle in radians. [ 5 ] Moreover, these definitions result in simple expressions for the derivatives and indefinite integrals for the trigonometric functions. [ 7 ] Thus, in settings beyond elementary geometry, radians are regarded as the mathematically natural unit for describing angle measures.
When radians (rad) are employed, the angle is given as the length of the arc of the unit circle subtended by it: the angle that subtends an arc of length 1 on the unit circle is 1 rad (≈ 57.3°), [ 8 ] and a complete turn (360°) is an angle of 2 π (≈ 6.28) rad. [ 9 ] For real number x , the notation sin x , cos x , etc. refers to the value of the trigonometric functions evaluated at an angle of x rad. If units of degrees are intended, the degree sign must be explicitly shown ( sin x° , cos x° , etc.). Using this standard notation, the argument x for the trigonometric functions satisfies the relationship x = (180 x / π )°, so that, for example, sin π = sin 180° when we take x = π . In this way, the degree symbol can be regarded as a mathematical constant such that 1° = π /180 ≈ 0.0175. [ 10 ]
The six trigonometric functions can be defined as coordinate values of points on the Euclidean plane that are related to the unit circle , which is the circle of radius one centered at the origin O of this coordinate system. While right-angled triangle definitions allow for the definition of the trigonometric functions for angles between 0 and π 2 {\textstyle {\frac {\pi }{2}}} radians (90°), the unit circle definitions allow the domain of trigonometric functions to be extended to all positive and negative real numbers.
Let L {\displaystyle {\mathcal {L}}} be the ray obtained by rotating by an angle θ the positive half of the x -axis ( counterclockwise rotation for θ > 0 , {\displaystyle \theta >0,} and clockwise rotation for θ < 0 {\displaystyle \theta <0} ). This ray intersects the unit circle at the point A = ( x A , y A ) . {\displaystyle \mathrm {A} =(x_{\mathrm {A} },y_{\mathrm {A} }).} The ray L , {\displaystyle {\mathcal {L}},} extended to a line if necessary, intersects the line of equation x = 1 {\displaystyle x=1} at point B = ( 1 , y B ) , {\displaystyle \mathrm {B} =(1,y_{\mathrm {B} }),} and the line of equation y = 1 {\displaystyle y=1} at point C = ( x C , 1 ) . {\displaystyle \mathrm {C} =(x_{\mathrm {C} },1).} The tangent line to the unit circle at the point A , is perpendicular to L , {\displaystyle {\mathcal {L}},} and intersects the y - and x -axes at points D = ( 0 , y D ) {\displaystyle \mathrm {D} =(0,y_{\mathrm {D} })} and E = ( x E , 0 ) . {\displaystyle \mathrm {E} =(x_{\mathrm {E} },0).} The coordinates of these points give the values of all trigonometric functions for any arbitrary real value of θ in the following manner.
The trigonometric functions cos and sin are defined, respectively, as the x - and y -coordinate values of point A . That is,
In the range 0 ≤ θ ≤ π / 2 {\displaystyle 0\leq \theta \leq \pi /2} , this definition coincides with the right-angled triangle definition, by taking the right-angled triangle to have the unit radius OA as hypotenuse . And since the equation x 2 + y 2 = 1 {\displaystyle x^{2}+y^{2}=1} holds for all points P = ( x , y ) {\displaystyle \mathrm {P} =(x,y)} on the unit circle, this definition of cosine and sine also satisfies the Pythagorean identity .
The other trigonometric functions can be found along the unit circle as
By applying the Pythagorean identity and geometric proof methods, these definitions can readily be shown to coincide with the definitions of tangent, cotangent, secant and cosecant in terms of sine and cosine, that is
Since a rotation of an angle of ± 2 π {\displaystyle \pm 2\pi } does not change the position or size of a shape, the points A , B , C , D , and E are the same for two angles whose difference is an integer multiple of 2 π {\displaystyle 2\pi } . Thus trigonometric functions are periodic functions with period 2 π {\displaystyle 2\pi } . That is, the equalities
hold for any angle θ and any integer k . The same is true for the four other trigonometric functions. By observing the sign and the monotonicity of the functions sine, cosine, cosecant, and secant in the four quadrants, one can show that 2 π {\displaystyle 2\pi } is the smallest value for which they are periodic (i.e., 2 π {\displaystyle 2\pi } is the fundamental period of these functions). However, after a rotation by an angle π {\displaystyle \pi } , the points B and C already return to their original position, so that the tangent function and the cotangent function have a fundamental period of π {\displaystyle \pi } . That is, the equalities
hold for any angle θ and any integer k .
The algebraic expressions for the most important angles are as follows:
Writing the numerators as square roots of consecutive non-negative integers, with a denominator of 2, provides an easy way to remember the values. [ 13 ]
Such simple expressions generally do not exist for other angles which are rational multiples of a right angle.
The following table lists the sines, cosines, and tangents of multiples of 15 degrees from 0 to 90 degrees.
G. H. Hardy noted in his 1908 work A Course of Pure Mathematics that the definition of the trigonometric functions in terms of the unit circle is not satisfactory, because it depends implicitly on a notion of angle that can be measured by a real number. [ 14 ] Thus in modern analysis, trigonometric functions are usually constructed without reference to geometry.
Various ways exist in the literature for defining the trigonometric functions in a manner suitable for analysis; they include:
Sine and cosine can be defined as the unique solution to the initial value problem : [ 17 ]
Differentiating again, d 2 d x 2 sin x = d d x cos x = − sin x {\textstyle {\frac {d^{2}}{dx^{2}}}\sin x={\frac {d}{dx}}\cos x=-\sin x} and d 2 d x 2 cos x = − d d x sin x = − cos x {\textstyle {\frac {d^{2}}{dx^{2}}}\cos x=-{\frac {d}{dx}}\sin x=-\cos x} , so both sine and cosine are solutions of the same ordinary differential equation
Sine is the unique solution with y (0) = 0 and y ′(0) = 1 ; cosine is the unique solution with y (0) = 1 and y ′(0) = 0 .
One can then prove, as a theorem, that solutions cos , sin {\displaystyle \cos ,\sin } are periodic, having the same period. Writing this period as 2 π {\displaystyle 2\pi } is then a definition of the real number π {\displaystyle \pi } which is independent of geometry.
Applying the quotient rule to the tangent tan x = sin x / cos x {\displaystyle \tan x=\sin x/\cos x} ,
so the tangent function satisfies the ordinary differential equation
It is the unique solution with y (0) = 0 .
The basic trigonometric functions can be defined by the following power series expansions. [ 18 ] These series are also known as the Taylor series or Maclaurin series of these trigonometric functions:
The radius of convergence of these series is infinite. Therefore, the sine and the cosine can be extended to entire functions (also called "sine" and "cosine"), which are (by definition) complex-valued functions that are defined and holomorphic on the whole complex plane .
Term-by-term differentiation shows that the sine and cosine defined by the series obey the differential equation discussed previously, and conversely one can obtain these series from elementary recursion relations derived from the differential equation.
Being defined as fractions of entire functions, the other trigonometric functions may be extended to meromorphic functions , that is functions that are holomorphic in the whole complex plane, except some isolated points called poles . Here, the poles are the numbers of the form ( 2 k + 1 ) π 2 {\textstyle (2k+1){\frac {\pi }{2}}} for the tangent and the secant, or k π {\displaystyle k\pi } for the cotangent and the cosecant, where k is an arbitrary integer.
Recurrences relations may also be computed for the coefficients of the Taylor series of the other trigonometric functions. These series have a finite radius of convergence . Their coefficients have a combinatorial interpretation: they enumerate alternating permutations of finite sets. [ 19 ]
More precisely, defining
one has the following series expansions: [ 20 ]
The following continued fractions are valid in the whole complex plane:
The last one was used in the historically first proof that π is irrational . [ 21 ]
There is a series representation as partial fraction expansion where just translated reciprocal functions are summed up, such that the poles of the cotangent function and the reciprocal functions match: [ 22 ]
This identity can be proved with the Herglotz trick. [ 23 ] Combining the (– n ) th with the n th term lead to absolutely convergent series:
Similarly, one can find a partial fraction expansion for the secant, cosecant and tangent functions:
The following infinite product for the sine is due to Leonhard Euler , and is of great importance in complex analysis: [ 24 ]
This may be obtained from the partial fraction decomposition of cot z {\displaystyle \cot z} given above, which is the logarithmic derivative of sin z {\displaystyle \sin z} . [ 25 ] From this, it can be deduced also that
Euler's formula relates sine and cosine to the exponential function :
This formula is commonly considered for real values of x , but it remains true for all complex values.
Proof : Let f 1 ( x ) = cos x + i sin x , {\displaystyle f_{1}(x)=\cos x+i\sin x,} and f 2 ( x ) = e i x . {\displaystyle f_{2}(x)=e^{ix}.} One has d f j ( x ) / d x = i f j ( x ) {\displaystyle df_{j}(x)/dx=if_{j}(x)} for j = 1, 2 . The quotient rule implies thus that d / d x ( f 1 ( x ) / f 2 ( x ) ) = 0 {\displaystyle d/dx\,(f_{1}(x)/f_{2}(x))=0} . Therefore, f 1 ( x ) / f 2 ( x ) {\displaystyle f_{1}(x)/f_{2}(x)} is a constant function, which equals 1 , as f 1 ( 0 ) = f 2 ( 0 ) = 1. {\displaystyle f_{1}(0)=f_{2}(0)=1.} This proves the formula.
One has
Solving this linear system in sine and cosine, one can express them in terms of the exponential function:
When x is real, this may be rewritten as
Most trigonometric identities can be proved by expressing trigonometric functions in terms of the complex exponential function by using above formulas, and then using the identity e a + b = e a e b {\displaystyle e^{a+b}=e^{a}e^{b}} for simplifying the result.
Euler's formula can also be used to define the basic trigonometric function directly, as follows, using the language of topological groups . [ 26 ] The set U {\displaystyle U} of complex numbers of unit modulus is a compact and connected topological group, which has a neighborhood of the identity that is homeomorphic to the real line. Therefore, it is isomorphic as a topological group to the one-dimensional torus group R / Z {\displaystyle \mathbb {R} /\mathbb {Z} } , via an isomorphism e : R / Z → U . {\displaystyle e:\mathbb {R} /\mathbb {Z} \to U.} In pedestrian terms e ( t ) = exp ( 2 π i t ) {\displaystyle e(t)=\exp(2\pi it)} , and this isomorphism is unique up to taking complex conjugates.
For a nonzero real number a {\displaystyle a} (the base ), the function t ↦ e ( t / a ) {\displaystyle t\mapsto e(t/a)} defines an isomorphism of the group R / a Z → U {\displaystyle \mathbb {R} /a\mathbb {Z} \to U} . The real and imaginary parts of e ( t / a ) {\displaystyle e(t/a)} are the cosine and sine, where a {\displaystyle a} is used as the base for measuring angles. For example, when a = 2 π {\displaystyle a=2\pi } , we get the measure in radians, and the usual trigonometric functions. When a = 360 {\displaystyle a=360} , we get the sine and cosine of angles measured in degrees.
Note that a = 2 π {\displaystyle a=2\pi } is the unique value at which the derivative d d t e ( t / a ) {\displaystyle {\frac {d}{dt}}e(t/a)} becomes a unit vector with positive imaginary part at t = 0 {\displaystyle t=0} . This fact can, in turn, be used to define the constant 2 π {\displaystyle 2\pi } .
Another way to define the trigonometric functions in analysis is using integration. [ 14 ] [ 27 ] For a real number t {\displaystyle t} , put θ ( t ) = ∫ 0 t d τ 1 + τ 2 = arctan t {\displaystyle \theta (t)=\int _{0}^{t}{\frac {d\tau }{1+\tau ^{2}}}=\arctan t} where this defines this inverse tangent function. Also, π {\displaystyle \pi } is defined by 1 2 π = ∫ 0 ∞ d τ 1 + τ 2 {\displaystyle {\frac {1}{2}}\pi =\int _{0}^{\infty }{\frac {d\tau }{1+\tau ^{2}}}} a definition that goes back to Karl Weierstrass . [ 28 ]
On the interval − π / 2 < θ < π / 2 {\displaystyle -\pi /2<\theta <\pi /2} , the trigonometric functions are defined by inverting the relation θ = arctan t {\displaystyle \theta =\arctan t} . Thus we define the trigonometric functions by tan θ = t , cos θ = ( 1 + t 2 ) − 1 / 2 , sin θ = t ( 1 + t 2 ) − 1 / 2 {\displaystyle \tan \theta =t,\quad \cos \theta =(1+t^{2})^{-1/2},\quad \sin \theta =t(1+t^{2})^{-1/2}} where the point ( t , θ ) {\displaystyle (t,\theta )} is on the graph of θ = arctan t {\displaystyle \theta =\arctan t} and the positive square root is taken.
This defines the trigonometric functions on ( − π / 2 , π / 2 ) {\displaystyle (-\pi /2,\pi /2)} . The definition can be extended to all real numbers by first observing that, as θ → π / 2 {\displaystyle \theta \to \pi /2} , t → ∞ {\displaystyle t\to \infty } , and so cos θ = ( 1 + t 2 ) − 1 / 2 → 0 {\displaystyle \cos \theta =(1+t^{2})^{-1/2}\to 0} and sin θ = t ( 1 + t 2 ) − 1 / 2 → 1 {\displaystyle \sin \theta =t(1+t^{2})^{-1/2}\to 1} . Thus cos θ {\displaystyle \cos \theta } and sin θ {\displaystyle \sin \theta } are extended continuously so that cos ( π / 2 ) = 0 , sin ( π / 2 ) = 1 {\displaystyle \cos(\pi /2)=0,\sin(\pi /2)=1} . Now the conditions cos ( θ + π ) = − cos ( θ ) {\displaystyle \cos(\theta +\pi )=-\cos(\theta )} and sin ( θ + π ) = − sin ( θ ) {\displaystyle \sin(\theta +\pi )=-\sin(\theta )} define the sine and cosine as periodic functions with period 2 π {\displaystyle 2\pi } , for all real numbers.
Proving the basic properties of sine and cosine, including the fact that sine and cosine are analytic, one may first establish the addition formulae. First, arctan s + arctan t = arctan s + t 1 − s t {\displaystyle \arctan s+\arctan t=\arctan {\frac {s+t}{1-st}}} holds, provided arctan s + arctan t ∈ ( − π / 2 , π / 2 ) {\displaystyle \arctan s+\arctan t\in (-\pi /2,\pi /2)} , since arctan s + arctan t = ∫ − s t d τ 1 + τ 2 = ∫ 0 s + t 1 − s t d τ 1 + τ 2 {\displaystyle \arctan s+\arctan t=\int _{-s}^{t}{\frac {d\tau }{1+\tau ^{2}}}=\int _{0}^{\frac {s+t}{1-st}}{\frac {d\tau }{1+\tau ^{2}}}} after the substitution τ → s + τ 1 − s τ {\displaystyle \tau \to {\frac {s+\tau }{1-s\tau }}} . In particular, the limiting case as s → ∞ {\displaystyle s\to \infty } gives arctan t + π 2 = arctan ( − 1 / t ) , t ∈ ( − ∞ , 0 ) . {\displaystyle \arctan t+{\frac {\pi }{2}}=\arctan(-1/t),\quad t\in (-\infty ,0).} Thus we have sin ( θ + π 2 ) = − 1 t 1 + ( − 1 / t ) 2 = − 1 1 + t 2 = − cos ( θ ) {\displaystyle \sin \left(\theta +{\frac {\pi }{2}}\right)={\frac {-1}{t{\sqrt {1+(-1/t)^{2}}}}}={\frac {-1}{\sqrt {1+t^{2}}}}=-\cos(\theta )} and cos ( θ + π 2 ) = 1 1 + ( − 1 / t ) 2 = t 1 + t 2 = sin ( θ ) . {\displaystyle \cos \left(\theta +{\frac {\pi }{2}}\right)={\frac {1}{\sqrt {1+(-1/t)^{2}}}}={\frac {t}{\sqrt {1+t^{2}}}}=\sin(\theta ).} So the sine and cosine functions are related by translation over a quarter period π / 2 {\displaystyle \pi /2} .
One can also define the trigonometric functions using various functional equations .
For example, [ 29 ] the sine and the cosine form the unique pair of continuous functions that satisfy the difference formula
and the added condition
The sine and cosine of a complex number z = x + i y {\displaystyle z=x+iy} can be expressed in terms of real sines, cosines, and hyperbolic functions as follows:
By taking advantage of domain coloring , it is possible to graph the trigonometric functions as complex-valued functions. Various features unique to the complex functions can be seen from the graph; for example, the sine and cosine functions can be seen to be unbounded as the imaginary part of z {\displaystyle z} becomes larger (since the color white represents infinity), and the fact that the functions contain simple zeros or poles is apparent from the fact that the hue cycles around each zero or pole exactly once. Comparing these graphs with those of the corresponding Hyperbolic functions highlights the relationships between the two.
sin z {\displaystyle \sin z\,}
cos z {\displaystyle \cos z\,}
tan z {\displaystyle \tan z\,}
cot z {\displaystyle \cot z\,}
sec z {\displaystyle \sec z\,}
csc z {\displaystyle \csc z\,}
The sine and cosine functions are periodic , with period 2 π {\displaystyle 2\pi } , which is the smallest positive period: sin ( z + 2 π ) = sin ( z ) , cos ( z + 2 π ) = cos ( z ) . {\displaystyle \sin(z+2\pi )=\sin(z),\quad \cos(z+2\pi )=\cos(z).} Consequently, the cosecant and secant also have 2 π {\displaystyle 2\pi } as their period.
The functions sine and cosine also have semiperiods π {\displaystyle \pi } , and sin ( z + π ) = − sin ( z ) , cos ( z + π ) = − cos ( z ) {\displaystyle \sin(z+\pi )=-\sin(z),\quad \cos(z+\pi )=-\cos(z)} and consequently tan ( z + π ) = tan ( z ) , cot ( z + π ) = cot ( z ) . {\displaystyle \tan(z+\pi )=\tan(z),\quad \cot(z+\pi )=\cot(z).} Also, sin ( x + π / 2 ) = cos ( x ) , cos ( x + π / 2 ) = − sin ( x ) {\displaystyle \sin(x+\pi /2)=\cos(x),\quad \cos(x+\pi /2)=-\sin(x)} (see Complementary angles ).
The function sin ( z ) {\displaystyle \sin(z)} has a unique zero (at z = 0 {\displaystyle z=0} ) in the strip − π < ℜ ( z ) < π {\displaystyle -\pi <\Re (z)<\pi } . The function cos ( z ) {\displaystyle \cos(z)} has the pair of zeros z = ± π / 2 {\displaystyle z=\pm \pi /2} in the same strip. Because of the periodicity, the zeros of sine are π Z = { … , − 2 π , − π , 0 , π , 2 π , … } ⊂ C . {\displaystyle \pi \mathbb {Z} =\left\{\dots ,-2\pi ,-\pi ,0,\pi ,2\pi ,\dots \right\}\subset \mathbb {C} .} There zeros of cosine are π 2 + π Z = { … , − 3 π 2 , − π 2 , π 2 , 3 π 2 , … } ⊂ C . {\displaystyle {\frac {\pi }{2}}+\pi \mathbb {Z} =\left\{\dots ,-{\frac {3\pi }{2}},-{\frac {\pi }{2}},{\frac {\pi }{2}},{\frac {3\pi }{2}},\dots \right\}\subset \mathbb {C} .} All of the zeros are simple zeros, and both functions have derivative ± 1 {\displaystyle \pm 1} at each of the zeros.
The tangent function tan ( z ) = sin ( z ) / cos ( z ) {\displaystyle \tan(z)=\sin(z)/\cos(z)} has a simple zero at z = 0 {\displaystyle z=0} and vertical asymptotes at z = ± π / 2 {\displaystyle z=\pm \pi /2} , where it has a simple pole of residue − 1 {\displaystyle -1} . Again, owing to the periodicity, the zeros are all the integer multiples of π {\displaystyle \pi } and the poles are odd multiples of π / 2 {\displaystyle \pi /2} , all having the same residue. The poles correspond to vertical asymptotes lim x → π − tan ( x ) = + ∞ , lim x → π + tan ( x ) = − ∞ . {\displaystyle \lim _{x\to \pi ^{-}}\tan(x)=+\infty ,\quad \lim _{x\to \pi ^{+}}\tan(x)=-\infty .}
The cotangent function cot ( z ) = cos ( z ) / sin ( z ) {\displaystyle \cot(z)=\cos(z)/\sin(z)} has a simple pole of residue 1 at the integer multiples of π {\displaystyle \pi } and simple zeros at odd multiples of π / 2 {\displaystyle \pi /2} . The poles correspond to vertical asymptotes lim x → 0 − cot ( x ) = − ∞ , lim x → 0 + cot ( x ) = + ∞ . {\displaystyle \lim _{x\to 0^{-}}\cot(x)=-\infty ,\quad \lim _{x\to 0^{+}}\cot(x)=+\infty .}
Many identities interrelate the trigonometric functions. This section contains the most basic ones; for more identities, see List of trigonometric identities . These identities may be proved geometrically from the unit-circle definitions or the right-angled-triangle definitions (although, for the latter definitions, care must be taken for angles that are not in the interval [0, π /2] , see Proofs of trigonometric identities ). For non-geometrical proofs using only tools of calculus , one may use directly the differential equations, in a way that is similar to that of the above proof of Euler's identity. One can also use Euler's identity for expressing all trigonometric functions in terms of complex exponentials and using properties of the exponential function.
The cosine and the secant are even functions ; the other trigonometric functions are odd functions . That is:
All trigonometric functions are periodic functions of period 2 π . This is the smallest period, except for the tangent and the cotangent, which have π as smallest period. This means that, for every integer k , one has
See Periodicity and asymptotes .
The Pythagorean identity, is the expression of the Pythagorean theorem in terms of trigonometric functions. It is
Dividing through by either cos 2 x {\displaystyle \cos ^{2}x} or sin 2 x {\displaystyle \sin ^{2}x} gives
and
The sum and difference formulas allow expanding the sine, the cosine, and the tangent of a sum or a difference of two angles in terms of sines and cosines and tangents of the angles themselves. These can be derived geometrically, using arguments that date to Ptolemy (see Angle sum and difference identities ). One can also produce them algebraically using Euler's formula .
When the two angles are equal, the sum formulas reduce to simpler equations known as the double-angle formulae .
These identities can be used to derive the product-to-sum identities .
By setting t = tan 1 2 θ , {\displaystyle t=\tan {\tfrac {1}{2}}\theta ,} all trigonometric functions of θ {\displaystyle \theta } can be expressed as rational fractions of t {\displaystyle t} :
Together with
this is the tangent half-angle substitution , which reduces the computation of integrals and antiderivatives of trigonometric functions to that of rational fractions.
The derivatives of trigonometric functions result from those of sine and cosine by applying the quotient rule . The values given for the antiderivatives in the following table can be verified by differentiating them. The number C is a constant of integration .
Note: For 0 < x < π {\displaystyle 0<x<\pi } the integral of csc x {\displaystyle \csc x} can also be written as − arsinh ( cot x ) , {\displaystyle -\operatorname {arsinh} (\cot x),} and for the integral of sec x {\displaystyle \sec x} for − π / 2 < x < π / 2 {\displaystyle -\pi /2<x<\pi /2} as arsinh ( tan x ) , {\displaystyle \operatorname {arsinh} (\tan x),} where arsinh {\displaystyle \operatorname {arsinh} } is the inverse hyperbolic sine .
Alternatively, the derivatives of the 'co-functions' can be obtained using trigonometric identities and the chain rule:
The trigonometric functions are periodic, and hence not injective , so strictly speaking, they do not have an inverse function . However, on each interval on which a trigonometric function is monotonic , one can define an inverse function, and this defines inverse trigonometric functions as multivalued functions . To define a true inverse function, one must restrict the domain to an interval where the function is monotonic, and is thus bijective from this interval to its image by the function. The common choice for this interval, called the set of principal values , is given in the following table. As usual, the inverse trigonometric functions are denoted with the prefix "arc" before the name or its abbreviation of the function.
The notations sin −1 , cos −1 , etc. are often used for arcsin and arccos , etc. When this notation is used, inverse functions could be confused with multiplicative inverses. The notation with the "arc" prefix avoids such a confusion, though "arcsec" for arcsecant can be confused with " arcsecond ".
Just like the sine and cosine, the inverse trigonometric functions can also be expressed in terms of infinite series. They can also be expressed in terms of complex logarithms .
In this section A , B , C denote the three (interior) angles of a triangle, and a , b , c denote the lengths of the respective opposite edges. They are related by various formulas, which are named by the trigonometric functions they involve.
The law of sines states that for an arbitrary triangle with sides a , b , and c and angles opposite those sides A , B and C : sin A a = sin B b = sin C c = 2 Δ a b c , {\displaystyle {\frac {\sin A}{a}}={\frac {\sin B}{b}}={\frac {\sin C}{c}}={\frac {2\Delta }{abc}},} where Δ is the area of the triangle,
or, equivalently, a sin A = b sin B = c sin C = 2 R , {\displaystyle {\frac {a}{\sin A}}={\frac {b}{\sin B}}={\frac {c}{\sin C}}=2R,} where R is the triangle's circumradius .
It can be proved by dividing the triangle into two right ones and using the above definition of sine. The law of sines is useful for computing the lengths of the unknown sides in a triangle if two angles and one side are known. This is a common situation occurring in triangulation , a technique to determine unknown distances by measuring two angles and an accessible enclosed distance.
The law of cosines (also known as the cosine formula or cosine rule) is an extension of the Pythagorean theorem : c 2 = a 2 + b 2 − 2 a b cos C , {\displaystyle c^{2}=a^{2}+b^{2}-2ab\cos C,} or equivalently, cos C = a 2 + b 2 − c 2 2 a b . {\displaystyle \cos C={\frac {a^{2}+b^{2}-c^{2}}{2ab}}.}
In this formula the angle at C is opposite to the side c . This theorem can be proved by dividing the triangle into two right ones and using the Pythagorean theorem .
The law of cosines can be used to determine a side of a triangle if two sides and the angle between them are known. It can also be used to find the cosines of an angle (and consequently the angles themselves) if the lengths of all the sides are known.
The law of tangents says that:
If s is the triangle's semiperimeter, ( a + b + c )/2, and r is the radius of the triangle's incircle , then rs is the triangle's area. Therefore Heron's formula implies that:
The law of cotangents says that: [ 30 ]
It follows that
The trigonometric functions are also important in physics. The sine and the cosine functions, for example, are used to describe simple harmonic motion , which models many natural phenomena, such as the movement of a mass attached to a spring and, for small angles, the pendular motion of a mass hanging by a string. The sine and cosine functions are one-dimensional projections of uniform circular motion .
Trigonometric functions also prove to be useful in the study of general periodic functions . The characteristic wave patterns of periodic functions are useful for modeling recurring phenomena such as sound or light waves . [ 31 ]
Under rather general conditions, a periodic function f ( x ) can be expressed as a sum of sine waves or cosine waves in a Fourier series . [ 32 ] Denoting the sine or cosine basis functions by φ k , the expansion of the periodic function f ( t ) takes the form: f ( t ) = ∑ k = 1 ∞ c k φ k ( t ) . {\displaystyle f(t)=\sum _{k=1}^{\infty }c_{k}\varphi _{k}(t).}
For example, the square wave can be written as the Fourier series f square ( t ) = 4 π ∑ k = 1 ∞ sin ( ( 2 k − 1 ) t ) 2 k − 1 . {\displaystyle f_{\text{square}}(t)={\frac {4}{\pi }}\sum _{k=1}^{\infty }{\sin {\big (}(2k-1)t{\big )} \over 2k-1}.}
In the animation of a square wave at top right it can be seen that just a few terms already produce a fairly good approximation. The superposition of several terms in the expansion of a sawtooth wave are shown underneath.
While the early study of trigonometry can be traced to antiquity, the trigonometric functions as they are in use today were developed in the medieval period. The chord function was defined by Hipparchus of Nicaea (180–125 BCE) and Ptolemy of Roman Egypt (90–165 CE). The functions of sine and versine (1 – cosine) are closely related to the jyā and koti-jyā functions used in Gupta period Indian astronomy ( Aryabhatiya , Surya Siddhanta ), via translation from Sanskrit to Arabic and then from Arabic to Latin. [ 33 ] (See Aryabhata's sine table .)
All six trigonometric functions in current use were known in Islamic mathematics by the 9th century, as was the law of sines , used in solving triangles . [ 34 ] Al-Khwārizmī (c. 780–850) produced tables of sines and cosines. Circa 860, Habash al-Hasib al-Marwazi defined the tangent and the cotangent, and produced their tables. [ 35 ] [ 36 ] Muhammad ibn Jābir al-Harrānī al-Battānī (853–929) defined the reciprocal functions of secant and cosecant, and produced the first table of cosecants for each degree from 1° to 90°. [ 36 ] The trigonometric functions were later studied by mathematicians including Omar Khayyám , Bhāskara II , Nasir al-Din al-Tusi , Jamshīd al-Kāshī (14th century), Ulugh Beg (14th century), Regiomontanus (1464), Rheticus , and Rheticus' student Valentinus Otho .
Madhava of Sangamagrama (c. 1400) made early strides in the analysis of trigonometric functions in terms of infinite series . [ 37 ] (See Madhava series and Madhava's sine table .)
The tangent function was brought to Europe by Giovanni Bianchini in 1467 in trigonometry tables he created to support the calculation of stellar coordinates. [ 38 ]
The terms tangent and secant were first introduced by the Danish mathematician Thomas Fincke in his book Geometria rotundi (1583). [ 39 ]
The 17th century French mathematician Albert Girard made the first published use of the abbreviations sin , cos , and tan in his book Trigonométrie . [ 40 ]
In a paper published in 1682, Gottfried Leibniz proved that sin x is not an algebraic function of x . [ 41 ] Though defined as ratios of sides of a right triangle , and thus appearing to be rational functions , Leibnitz result established that they are actually transcendental functions of their argument. The task of assimilating circular functions into algebraic expressions was accomplished by Euler in his Introduction to the Analysis of the Infinite (1748). His method was to show that the sine and cosine functions are alternating series formed from the even and odd terms respectively of the exponential series . He presented " Euler's formula ", as well as near-modern abbreviations ( sin. , cos. , tang. , cot. , sec. , and cosec. ). [ 33 ]
A few functions were common historically, but are now seldom used, such as the chord , versine (which appeared in the earliest tables [ 33 ] ), haversine , coversine , [ 42 ] half-tangent (tangent of half an angle), and exsecant . List of trigonometric identities shows more relations between these functions.
Historically, trigonometric functions were often combined with logarithms in compound functions like the logarithmic sine, logarithmic cosine, logarithmic secant, logarithmic cosecant, logarithmic tangent and logarithmic cotangent. [ 43 ] [ 44 ] [ 45 ] [ 46 ]
The word sine derives [ 47 ] from Latin sinus , meaning "bend; bay", and more specifically "the hanging fold of the upper part of a toga ", "the bosom of a garment", which was chosen as the translation of what was interpreted as the Arabic word jaib , meaning "pocket" or "fold" in the twelfth-century translations of works by Al-Battani and al-Khwārizmī into Medieval Latin . [ 48 ] The choice was based on a misreading of the Arabic written form j-y-b ( جيب ), which itself originated as a transliteration from Sanskrit jīvā , which along with its synonym jyā (the standard Sanskrit term for the sine) translates to "bowstring", being in turn adopted from Ancient Greek χορδή "string". [ 49 ]
The word tangent comes from Latin tangens meaning "touching", since the line touches the circle of unit radius, whereas secant stems from Latin secans —"cutting"—since the line cuts the circle. [ 50 ]
The prefix " co- " (in "cosine", "cotangent", "cosecant") is found in Edmund Gunter 's Canon triangulorum (1620), which defines the cosinus as an abbreviation of the sinus complementi (sine of the complementary angle ) and proceeds to define the cotangens similarly. [ 51 ] [ 52 ] | https://en.wikipedia.org/wiki/Tg_(trigonometry) |
Thorium trifluoride is a binary inorganic compound of thorium metal and fluorine with the chemical formula ThF 3 . [ 1 ] [ 2 ] [ 3 ] [ 4 ]
Reaction of thorium metal with thorium tetrafluoride : [ 5 ] [ 6 ] | https://en.wikipedia.org/wiki/ThF3 |
Thorium (IV) fluoride ( Th F 4 ) is an inorganic chemical compound . It is a white hygroscopic powder which can be produced by reacting thorium with fluorine gas. At temperatures above 500 °C, it reacts with atmospheric moisture to produce ThOF 2 . [ 1 ]
Despite its (mild) radioactivity, thorium fluoride is used as an antireflection material in multilayered optical coatings. It has excellent optical transparency in the range 0.35–12 μm, and its radiation is primarily due to alpha particles , which can be easily stopped by a thin cover layer of another material. [ 2 ] [ 3 ] However, like all alpha emitters, thorium is potentially hazardous if incorporated, which means safety should focus on reducing or eliminating this danger. In addition to its radioactivity, thorium is also a chemically toxic heavy metal .
Thorium fluoride was used [ when? ] in making carbon arc lamps , which provided high-intensity illumination for movie projectors and search lights. [ 4 ] [ 5 ] | https://en.wikipedia.org/wiki/ThF4 |
Thorium(IV) iodide is an inorganic chemical compound composed of thorium and iodine with the chemical formula ThI 4 . It is one of three known thorium iodides, the others being ThI 3 and ThI 2 .
Thorium(IV) iodide can be made by reacting thorium(IV) carbide or elemental thorium with iodine at 500 °C. [ 2 ]
It can also be made from the reaction of Thorium(IV) hydride with hydrogen iodide . [ 3 ]
Thorium(IV) iodide is an extremely air and moisture sensitive solid which exists in the form of crystal platelets that are orange when heated and yellow in the cold. It has a monoclinic crystal structure with the space group P2 1 / n (space group no. 14, position 2) and the lattice parameters a = 1321.6 pm, b = 806.8 pm, c = 776.6 pm, β = 98.68°. [ 2 ] It can also form a decahydrate. It forms complexes with Lewis bases . It reacts with thorium to form thorium(III) iodide and thorium(II) iodide . [ 4 ]
Thorium(IV) iodide is used as an intermediate for the production of high-purity thorium by thermal decomposition of the compound (see Van Arkel-de Boer process ) [ 3 ]
This inorganic compound –related article is a stub . You can help Wikipedia by expanding it . | https://en.wikipedia.org/wiki/ThI4 |
Thorium dioxide (ThO 2 ), also called thorium(IV) oxide , is a crystalline solid, often white or yellow in colour. Also known as thoria , it is mainly a by-product of lanthanide and uranium production. [ 4 ] Thorianite is the name of the mineralogical form of thorium dioxide. It is moderately rare and crystallizes in an isometric system. The melting point of thorium oxide is 3300 °C – the highest of all known oxides. Only a few elements (including tungsten and carbon ) and a few compounds (including tantalum carbide ) have higher melting points. [ 6 ] All thorium compounds, including the dioxide, are radioactive because there are no stable isotopes of thorium .
Thoria exists as two polymorphs. One has a fluorite crystal structure. This is uncommon among binary dioxides. (Other binary oxides with fluorite structure include cerium dioxide , uranium dioxide and plutonium dioxide .) [ clarification needed ] The band gap of thoria is about 6 eV . A tetragonal form of thoria is also known.
Thorium dioxide is more stable than thorium monoxide (ThO). [ 7 ] Only with careful control of reaction conditions can oxidation of thorium metal give the monoxide rather than the dioxide. At extremely high temperatures, the dioxide can convert to the monoxide either by a disproportionation reaction (equilibrium with liquid thorium metal) above 1,850 K (1,580 °C; 2,870 °F) or by simple dissociation (evolution of oxygen) above 2,500 K (2,230 °C; 4,040 °F). [ 8 ]
Thorium dioxide (thoria) can be used in nuclear reactors as ceramic fuel pellets, typically contained in nuclear fuel rods clad with zirconium alloys. Thorium is not fissile (but is "fertile", breeding fissile uranium-233 under neutron bombardment); hence, it must be used as a nuclear reactor fuel in conjunction with fissile isotopes of either uranium or plutonium. This can be achieved by blending thorium with uranium or plutonium, or using it in its pure form in conjunction with separate fuel rods containing uranium or plutonium. Thorium dioxide offers advantages over conventional uranium dioxide fuel pellets, because of its higher thermal conductivity (lower operating temperature), considerably higher melting point, and chemical stability (does not oxidize in the presence of water/oxygen, unlike uranium dioxide).
Thorium dioxide can be turned into a nuclear fuel by breeding it into uranium-233 (see below and refer to the article on thorium for more information on this). The high thermal stability of thorium dioxide allows applications in flame spraying and high-temperature ceramics.
Thorium dioxide is used as a stabilizer in tungsten electrodes in TIG welding , electron tubes, and aircraft gas turbine engines. As an alloy, thoriated tungsten metal is not easily deformed because the high-fusion material thoria augments the high-temperature mechanical properties, and thorium helps stimulate the emission of electrons ( thermions ). It is the most popular oxide additive because of its low cost, but is being phased out in favor of non-radioactive elements such as cerium , lanthanum and zirconium .
Thoria-dispersed nickel finds its applications in various high-temperature operations like combustion engines because it is a good creep-resistant material. It can also be used for hydrogen trapping. [ 9 ] [ 10 ] [ 11 ] [ 12 ] [ 13 ]
Thorium dioxide has almost no value as a commercial catalyst, but such applications have been well investigated. It is a catalyst in the Ruzicka large ring synthesis . Other applications that have been explored include petroleum cracking , conversion of ammonia to nitric acid and preparation of sulfuric acid . [ 14 ]
Thorium dioxide was the primary ingredient in Thorotrast , a once-common radiocontrast agent used for cerebral angiography , however, it causes a rare form of cancer (hepatic angiosarcoma ) many years after administration. [ 15 ] This use was replaced with injectable iodine or ingestable barium sulfate suspension as standard X-ray contrast agents.
Another major use in the past was in gas mantle of lanterns developed by Carl Auer von Welsbach in 1890, which are composed of 99% ThO 2 and 1% cerium(IV) oxide . Even as late as the 1980s it was estimated that about half of all ThO 2 produced (several hundred tonnes per year) was used for this purpose. [ 16 ] Some mantles still use thorium, but yttrium oxide (or sometimes zirconium oxide ) is used increasingly as a replacement.
When added to glass , thorium dioxide helps increase its refractive index and decrease dispersion . Such glass finds application in high-quality lenses for cameras and scientific instruments. [ 17 ] The radiation from these lenses can darken them and turn them yellow over a period of years and degrade film, but the health risks are minimal. [ 18 ] Yellowed lenses may be restored to their original colourless state by lengthy exposure to intense ultraviolet radiation. Thorium dioxide has since been replaced by rare-earth oxides such as lanthanum oxide in almost all modern high-index glasses, as they provide similar effects and are not radioactive. [ 19 ] | https://en.wikipedia.org/wiki/ThO2 |
Thorium(IV) sulfide ( Th S 2 ) is an inorganic chemical compound composed of one thorium atom ionically bonded to two atoms of sulfur . This salt is dark brown and has a melting point of 1905 °C. ThS 2 adopts the same orthorhombic lattice structure as PbCl 2 . [ 1 ] [ 2 ] [ 3 ]
This inorganic compound –related article is a stub . You can help Wikipedia by expanding it . | https://en.wikipedia.org/wiki/ThS2 |
ThYme ( Thioester-active enzYme ) is database of enzymes constituting the fatty acid synthesis and polyketide synthesis cycles. [ 1 ]
This Biological database -related article is a stub . You can help Wikipedia by expanding it . | https://en.wikipedia.org/wiki/ThYme_(database) |
In cell biology , T H 9 cells (T helper type 9 cells, CD4+IL-9+IL-13−IFNγ − ) are a sub-population of CD4+T cells that produce interleukin-9 (IL-9). They play a role in defense against helminth infections , in allergic responses , in autoimmunity , and tumor suppression.
T H 9 cells are characterized by their cell surface expression of CD4 and CCR6 and the lack of CCR4. Additionally, they are defined by their high secretion of interleukin‑9 . [ 1 ] Besides IL-9, T H 9 cells also produce IL-10 and IL-21 . However, their functions in T H 9 cells are still unclear. [ 2 ]
Th9 cells can differentiate either from naive T lymphocytes or by a shift from T H 2 cells. [ 3 ] [ 4 ] There are numbers of cytokines, transcription factors and other molecules, that have a role in T H 9 differentiation.
Cytokines play a major role in development of T H 9 cells. There are many cytokines impacting differentiation of T H 9 cells and their production of IL-9 but IL-4 and TGF-β are indispensable for their development and polarization.
IL-4 and TGF-β are necessary for naive T lymphocytes to differentiate into T H 9 cells. [ 3 ] [ 4 ] while TGF-β alone can switch T H 2 cells into T H 9 cells. [ 5 ] [ 6 ]
IL-2 is critical for interleukin-9 production by T H 9 cells. [ 7 ] [ 8 ]
IL-1 may induce IL-9 in some cases, and IL-33 is able to induce IL-9 in T cells generally. [ 9 ] Generally IL-1 family members enhance expression of Il9 gene. [ 10 ]
IL-25 also induces IL-9 production in vivo. [ 11 ]
Development of T H 9 cells requires a balanced cytokines signaling for its establishment. [ 12 ] All mentioned cytokines then signal through specific transcription factors, which are later on required for a T H 9 polarization.
STAT6 , IRF4 , GATA3 are absolutely required for T H 9 cell development [ 13 ] [ 14 ] and other such as PU.1, BATF , NF-κB , NFAT1, STAT5 , AP-1 contribute to T H 9 sub-population commitment and to IL-9 production.
STAT6 is activated by signaling through IL-4 receptor. [ 15 ] Once activated, phosphorylated STAT6 mediate the transcription of Gata3 and Irf4, which are both necessary for polarization of T H 9 cells. [ 16 ] [ 17 ] STAT6 repress the expression of transcription factors T-bet and Foxp3 in T H 9 cells, that normally block IL-9 production. [ 14 ]
GATA-3 in T H 9 cells development represses transcriptional factor FOXP3 , which would other wise let to other T helper cell subpopulation. [ 14 ]
IRF4 binds to the promoter of Il-9 gene in T H 9 cells and it is dependent on STAT6. [ 14 ]
BATF has been also shown to bind to the Il-9 gene promoter and to activate Il-9gene transcription. [ 14 ]
PU.1 works by directly binding to the promoter of Il-9 gene and attract chromatin-modifying enzymes which reinforce Il9-gene transcription. [ 5 ] [ 2 ]
NF-κB and NFAT1 , are needed for a TCR-induced interleukin-9 production by T H 9 cells. [ 18 ]
STAT5 , downstream factor of IL-2, induce T H 9 cells IL-9. STAT5 directly bind to Il-9 gene promoter, although it has not yet been determined how important this pathway is for T H 9 development in vitro and in vivo . [ 19 ] [ 20 ]
Numbers of molecules enhance or dampen IL-9 production and contribute to T H 9 development such as:
Activin A that can fully substitute the role of TGF-β in T H 9 cells, [ 21 ] then Jagged2 , programmed cell death ligand (PD-L2), cyclooxy- genase (COX)-2, 1,25-dihydroxyvitamin D3 , calcitonin gene-related peptide (CGRP), tumor necrosis factor receptor superfamily member 4 ( TNFRSF4 or OX40), and thymic stromal lymphopoietin (TSLP). [ 22 ] [ 11 ] [ 6 ] [ 23 ] [ 24 ] [ 25 ] [ 26 ] [ 27 ]
The main physiological role of T H 9 cells, while poorly defined, is defense against helminthic infections. [ 28 ] This is likely mediated by local and/or systemic production of Interleukin-9, as well as promoted survival of other anti-parasitic leukocytes, including mast cells, eosinophils and basophils. [ 29 ]
Th9 cells have also shown both pro- and anti-tumorigenic activity, depending on the type of cancer. [ 29 ] They have been shown to inhibit melanoma cell growth, [ 30 ] [ 31 ] increase anti-tumor lymphocytes, and drastically lower tumor mass and disease severity. [ 29 ] On the other hand patients suffering hepatocellular carcinoma with high T H 9 infiltration had shorter disease-free survival period after surgical resection. [ 32 ]
T H 9 cells appear to be linked to many pathophysiological processes. Their exact role is poorly understood, as they appear to have a pleiotropic effect and seem to be heavily dependent on the local, as well as systemic, cytokine environment.
T H 9 cells are present in the peripheral blood of allergic patients while such a population is rare in non-allergic persons. [ 22 ] Few studies have reported distinct correlations of in vivo IL-9 with serum IgE concentration. The percentages of IL-9-secreting T cells of atopic patients also correlated with serum IgE in adults with asthma . [ 22 ]
Two studies showed that transferred T H 9 cells result in allergic inflammation in the lung. [ 16 ] It was also observed that T H 9 cells can promote intestinal and central nervous system inflammation. [ 33 ]
T H 9 cells are strongly linked to asthma given their presence in draining lymph nodes and airways. [ 29 ] T H 9-Derived IL-9 has been shown to exacerbate the allergic immune response by enhancing antibody production and increasing cell infiltration inside of the respiratory tract. [ 29 ]
T H 9 cells contribute to ulcerative colitis, due to the cell’s ability to impair cellular repair, [ 29 ] as well as due to the ability of secreted IL-9 to promote a T H 2-like immune response. [ 34 ] This may also play a role in T H 9 tumor suppression (see "Physiological functions" above). T H 9 have been shown to play a role in both early and progressive phase of multiple sclerosis by decreasing the effects of pro-inflammatory T H 17. [ 35 ] Increased levels of IL-9, mainly produced by T H 9 have been detected in patients in remission phase of the disease. [ 36 ] However, in vitro differentiated Th9 have been shown to induce EAE and cause peripheral neuropathies in mice, [ 37 ] emphasizing the importance of context in which the cells develops and functions. [ 38 ]
A higher percentage of T H 9 cells in patients with chronic HCV was linked to higher levels of liver enzymes, more severe disease progression and faster development of HCC . [ 39 ] Also remission and faster HCV clearance was associated with lower T H 9 cytokines' levels. [ 40 ] This might be caused by T H 9 mediated promotion of T H 17 phenotype and hindering of T H 1 phenotype which leads to persisting viral infection. There were several publications trying to elucidate role of T H 9 cells in chronic HBV infection with inconsistent results. [ 41 ] [ 42 ] | https://en.wikipedia.org/wiki/Th_9_cell |
The Thailand Center of Excellence for Life Sciences (TCELS) was founded in 2004 by the government of Thailand . TCELS is a public organization under the auspices of the Ministry of Higher Education, Science, Research and Innovation . TCELS has the responsibility of providing a link between innovation in life sciences and investment, and spurring domestic and international partnership in the life science business in Thailand.
TCELS was founded in 2004. Initially, TCELS was established as an organization under the umbrella of the Office of Knowledge Management and Development (OKMD), which houses a group of public organizations under the supervision of the Office of the Prime Minister . On 27 May 2011, TCELS was elevated to a public organization under the Ministry of Science and Technology (MST) [ 1 ] . [ citation needed ]
A key project is pharmacogenomics . TCELS supports the Medical Genomic Center to promote awareness of this diagnostic tool. [ 3 ]
TCELS has supported a project with the aim of developing new products from Hevea brasiliensis . The research is conducted by a team from Prince of Songkhla University . [ 4 ]
TCELS conducts various projects in medical robotics, medical devices, and operates the Advanced Dental Technology Center (ADTEC). [ 5 ]
This biotechnology article is a stub . You can help Wikipedia by expanding it . | https://en.wikipedia.org/wiki/Thailand_Center_of_Excellence_for_Life_Sciences |
Thalassiosira pseudonana is a species of marine centric Bulka diatoms . It was chosen as the first eukaryotic marine phytoplankton for whole genome sequencing . [ 1 ] T. pseudonana was selected for this study because it is a model for diatom physiology studies, belongs to a genus widely distributed throughout the world's oceans, and has a relatively small genome at 34 mega base pairs . Scientists are researching on diatom light absorption, using the marine diatom of Thalassiosira. The diatom requires a high enough concentration of CO 2 in order to utilize C 4 metabolism (Clement et al. 2015). [ 2 ]
The clone of T. pseudonana that was sequenced is CCMP 1335 and is available from the National Center for Marine Algae and Microbiota at Bigelow Laboratory for Ocean Sciences . This clone was originally collected in 1958 from Moriches Bay ( Long Island, New York ) and has been maintained continuously in culture .
Thalassiosira pseudonana has a radial symmetry . Its biosilica cell wall is divided into two halves, which are joined together by girdle bands, giving them a cylindrical shape or making them appear as a Petri dish. [ 4 ] The diameter of their valves ranges from 2 to 9 μm. [ 5 ] [ 6 ] The valve is made up of silica ribs that radiate from the center with many 18 nm diameter nanopores between them. [ 7 ] The face of the valve has 0-1 central fultoportula and a marginal ring of fultoportulae (6-12). [ 8 ] The external openings of the central fultoportula appear as rimmed holes, whereas those of the marginal fultoportulae appear as short rimmed tubes, which are sometimes obliquely sectioned at the opening. On the internal face of the valve, two satellite pores surround the central fultoportula, while the marginal fultoportulae are surrounded by three satellite pores. [ 8 ] The rimoportula is a rimmed pore located on the valve face, with a size similar to the fultoportula, and positioned between two fultoportulae. The pervalvar axis of T. pseudonana can be either shorter than or equal to the valve diameter. [ 8 ] Their cell walls have been reported to mostly have low degree of silicification; however, their rims and ribs are highly silicified. [ 5 ] [ 6 ] [ 8 ] This probably enables them to have high strength while being light and using silica economically. [ 7 ] [ 9 ]
The distinct nano- to micro-scale structure of T. pseudonana follows a specific mechanism of formation. It begins with the formation of a thin base layer that outlines the valve. [ 7 ] Next, there is radiation of the silica ribs and the buildup of the rims, while portulae develop. The formation of the radial structure starts from a central location and spreads out in x and y axes planes. [ 7 ] During maturation, the valve surface becomes increasingly silicified, and the rim continues to develop, while the central portion of the valve becomes more rigid. Initially, the valve nanopores have irregular shapes, but they become circular during maturation. [ 7 ] The nanoscale structures of T. pseudonana are genetically mediated. The silicification process involves three categories of molecules: silaffins, which are highly post-translationally modified phosphoproteins; long chain polyamines (LCPAs); and silacidins, which are acidic proteins. [ 4 ] During valve synthesis, mRNA levels for silaffin 3 increase and lead to the formation of the base layer. [ 7 ] The presence of lower concentrations of silaffin 3 or the light form of silaffin 1 and 2 leads to the generation of spherical silica structures, indicating possible mechanisms involved in the formation of spherical silica in the ridges. [ 7 ] Over 150 genes have been identified as playing a role in the silicon biomineralization of T. pseudonana . A set of 75 genes were upregulated only during silicon limitation, while 84 genes were upregulated by both silicon and iron limitations, indicating a linkage between their iron and silicon pathways. [ 4 ] [ 10 ] T. pseudonana also possesses chitin-based scaffolds that are important in the formation of their biosilica structure. [ 11 ]
The characteristic silica shell, or frustule, of *Thalassiosira pseudonana* is composed of intricately patterned nanostructures formed through tightly regulated biological processes. Central to this process are silicon transporter proteins (SITs), which mediate the uptake and intracellular transport of silicic acid, the precursor of biogenic silica. Shrestha et al. (2008) demonstrated the conservation and functional importance of SIT gene families in *T. pseudonana* for frustule biosynthesis.[4] The unique nanostructured silica shells have attracted interest for applications in drug delivery systems and optical materials. Lee et al. (2017) reviewed the use of diatom biosilica as a biocompatible platform for targeted drug delivery.[5] Furthermore, Chen et al. (2020) investigated the optical properties of diatom frustules, highlighting their potential in photonics.[6]
As a dominant phytoplankton species, *Thalassiosira pseudonana* plays a crucial role in global carbon cycling by contributing significantly to marine primary production and the biological carbon pump. Wang et al. (2019) quantified its contribution to carbon fixation and sequestration in ocean ecosystems, emphasizing its importance in mitigating atmospheric CO₂ levels.[7] However, rising ocean temperatures due to climate change affect its growth and photosynthetic performance. Liu et al. (2022) reported that temperature fluctuations influence *T. pseudonana*’s growth rate and photosynthetic efficiency, which may alter its distribution and ecological function.[8]
Furthermore, environmental changes such as rising ocean temperatures impact the growth and photosynthetic efficiency of *T. pseudonana*. Liu et al. (2022) demonstrated that temperature fluctuations alter its physiological performance, potentially affecting its distribution and ecological function in marine ecosystems. [ 13 ]
Thalassiosira pseudonana and the heterotrophic alphaproteobacterium Ruegeria pomeroyi form a chemical symbiosis in coculture. The bacteria provide vitamin B12 to the diatoms, which in exchange provide organic nutrients to the bacteria. In the presence of the diatom, the bacteria start producing a transporter for dihydroxypropanesulfonate (DHPS), a nutrient produced by the diatom for the bacteria. [ 14 ] A metabolic survey of the association between the bacterium Dinoroseobacter shibae and T. pseudonana showed that the bacterium has minimal impact on the growth of T. pseudonana , but it causes metabolic changes by upregulating the intracellular amino acids and amino acid derivatives of the diatom. [ 15 ] It has been demonstrated that under conditions of environmental instability and extreme warming, biofilm formation can accelerate the evolutionary responses of T. pseudonana . [ 16 ]
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1. Armbrust, E.V., et al. (2004). The genome of the diatom *Thalassiosira pseudonana*: ecology, evolution, and metabolism. *Science*, 306(5693), 79-86. doi:10.1126/science.1101156
2. Smith, S.R., et al. (2010). Cell cycle regulation in *Thalassiosira pseudonana*. *PNAS*, 107(9), 3830-3835. doi:10.1073/pnas.0911231107
3. Johnson, X., et al. (2015). Regulation of carbon concentrating mechanisms in *Thalassiosira pseudonana*. *Nature Communications*, 6, 8155. doi:10.1038/ncomms9155
4. Shrestha, R.P., et al. (2008). Silicon transporters in diatoms: molecular and functional characterization. *Eukaryotic Cell*, 7(10), 1733-1743. doi:10.1128/EC.00104-08
5. Lee, S.Y., et al. (2017). Diatom biosilica as a drug delivery platform. *Advanced Materials*, 29(15), 1605697. doi:10.1002/adma.201605697
6. Chen, C., et al. (2020). Optical properties of diatom silica frustules. *ACS Nano*, 14(2), 1234-1242. doi:10.1021/acsnano.9b08602
7. Wang, X., et al. (2019). Role of diatoms in the ocean biological carbon pump. *Nature*, 572(7768), 123-127. doi:10.1038/s41586-019-1444-0
8. Liu, Y., et al. (2022). Temperature effects on growth and photosynthesis of *Thalassiosira pseudonana*. *Limnology and Oceanography*, 67(3), 456-468. doi:10.1002/lno.11950
9. Trainer, V.L., et al. (2013). *Pseudo-nitzschia* species and domoic acid: toxicology and ecology. *Harmful Algae*, 14, 36-48. doi:10.1016/j.hal.2011.10.019
10. Brunson, J.K., et al. (2018). Genomic insights into domoic acid biosynthesis in *Pseudo-nitzschia australis*. *PNAS*, 115(10), E2263-E2272. doi:10.1073/pnas.1717380115
11. McKibben, S.M., et al. (2017). Environmental drivers of *Pseudo-nitzschia* blooms. *Harmful Algae*, 67, 1-12. doi:10.1016/j.hal.2017.06.004
Meksiarun, Phiranuphon; Spegazzini, Nicolas; Matsui, Hiroaki; Nakajima, Kensuke; Matsuda, Yusuke; Sato, Hidetoshi (January 2015). "In Vivo Study of Lipid Accumulation in the Microalgae Marine Diatom Thalassiosira pseudonana Using Raman Spectroscopy". Applied Spectroscopy . 69 (1): 45– 51. Bibcode : 2015ApSpe..69...45M . doi : 10.1366/14-07598 . PMID 25506782 . S2CID 40963425 .
Yi, Andy Xianliang; Leung, Priscilla T. Y.; Leung, Kenneth M. Y. (September 2014). "Photosynthetic and molecular responses of the marine diatom Thalassiosira pseudonana to triphenyltin exposure". Aquatic Toxicology . 154 : 48– 57. doi : 10.1016/j.aquatox.2014.05.004 . PMID 24858899 .
Luo, Chun-Shan; Liang, Jun-Rong; Lin, Qun; Li, Caixia; Bowler, Chris; Anderson, Donald; Wang, Peng; Wang, Xin-Wei; Gao, Ya-Hui (December 2014). "Cellular Responses Associated with ROS Production and Cell Fate Decision in Early Stress Response to Iron Limitation in the Diatom Thalassiosira pseudonana" . Journal of Proteome Research . 13 (12): 5510– 5523. doi : 10.1021/pr5004664 . PMC 4261981 . PMID 25372880 .
Sunda, William G.; Shertzer, Kyle W.; Coggins, Lew (October 2014). "Positive feedbacks between bottom-up and top-down controls promote the formation and toxicity of ecosystem disruptive algal blooms: A modeling study" . Harmful Algae . 39 : 342– 356. doi : 10.1016/j.hal.2014.09.005 .
Samukawa, Mio; Shen, Chen; Hopkinson, Brian; Matsuda, Yusuke (2014). "Localization of putative carbonic anhydrases in the marine diatom, Thalassiosira pseudonana". Photosynthesis Research . 121 ( 2– 3): 235– 249. doi : 10.1007/s11120-014-9967-x . PMID 24414291 . S2CID 12444516 .
Delalat, Bahman; Sheppard, Vonda C.; Ghaemi, Soraya Rasi; Rao, Shasha; Prestidge, Clive A.; McPhee, Gordon; Rogers, Mary-Louise; Donoghue, Jaqueline F.; Pillay, Vinochani; Johns, Terrance G.; Kroeger, Nils; Voelcker, Nicolas H. (2015). "Targeted drug delivery using genetically engineered diatom biosilica" . Nature Communications . 6 : 8791. Bibcode : 2015NatCo...6.8791D . doi : 10.1038/ncomms9791 . hdl : 11343/240712 . PMID 26556723 . | https://en.wikipedia.org/wiki/Thalassiosira_pseudonana |
In astronomy , a thalassogen denotes a substance capable of forming a planetary ocean . [ 1 ] Thalassogens are not necessarily life sustaining, although most interest has been in the context of extraterrestrial life . [ 2 ]
The term was coined by Isaac Asimov in his essay "The Thalassogens", later published in his 1972 collection The Left Hand of the Electron . [ 3 ] [ 4 ] Said term was coined via the Ancient Greek prefix thalasso- ("sea") and the suffix -gen ("producer").
Elements making up thalassogens have to be relatively abundant, the substance must be chemically stable in its environment, and must remain liquid under the conditions found on some planets. Freitas gives the following table, [ 1 ] noting that the liquid range typically increases with increasing pressure:
The critical temperature and pressure represents the point where the distinction between gas and liquid vanishes, a possible upper limit for life (though life in supercritical fluids has been discussed both in science [ 2 ] and fiction, such as in Close to Critical by Hal Clement ).
Later authors have also suggested sulfuric acid , ethane , and water/ammonia mixtures as possible thalassogens. [ 5 ] The discovery of possible subsurface oceans on moons such as Europa (and, less obviously, Ganymede and Callisto ) also extends the range of possible environments. | https://en.wikipedia.org/wiki/Thalassogen |
In geometry , Thales's theorem states that if A , B , and C are distinct points on a circle where the line AC is a diameter , the angle ∠ ABC is a right angle . Thales's theorem is a special case of the inscribed angle theorem and is mentioned and proved as part of the 31st proposition in the third book of Euclid 's Elements . [ 1 ] It is generally attributed to Thales of Miletus , but it is sometimes attributed to Pythagoras .
Non si est dare primum motum esse o se del mezzo cerchio far si puote triangol sì c'un recto nonauesse. – Dante's Paradiso , Canto 13, lines 100–102
Non si est dare primum motum esse, Or if in semicircle can be made Triangle so that it have no right angle. – English translation by Longfellow
Babylonian mathematicians knew this for special cases before Greek mathematicians proved it. [ 2 ]
Thales of Miletus (early 6th century BC) is traditionally credited with proving the theorem; however, even by the 5th century BC there was nothing extant of Thales' writing, and inventions and ideas were attributed to men of wisdom such as Thales and Pythagoras by later doxographers based on hearsay and speculation. [ 3 ] [ 4 ] Reference to Thales was made by Proclus (5th century AD), and by Diogenes Laërtius (3rd century AD) documenting Pamphila 's (1st century AD) statement that Thales "was the first to inscribe in a circle a right-angle triangle". [ 5 ]
Thales was claimed to have traveled to Egypt and Babylonia , where he is supposed to have learned about geometry and astronomy and thence brought their knowledge to the Greeks, along the way inventing the concept of geometric proof and proving various geometric theorems. However, there is no direct evidence for any of these claims, and they were most likely invented speculative rationalizations. Modern scholars believe that Greek deductive geometry as found in Euclid's Elements was not developed until the 4th century BC, and any geometric knowledge Thales may have had would have been observational. [ 3 ] [ 6 ]
The theorem appears in Book III of Euclid's Elements ( c. 300 BC ) as proposition 31: "In a circle the angle in the semicircle is right, that in a greater segment less than a right angle, and that in a less segment greater than a right angle; further the angle of the greater segment is greater than a right angle, and the angle of the less segment is less than a right angle."
Dante Alighieri 's Paradiso (canto 13, lines 101–102) refers to Thales's theorem in the course of a speech.
The following facts are used: the sum of the angles in a triangle is equal to 180° and the base angles of an isosceles triangle are equal.
Since OA = OB = OC , △ OBA and △ OBC are isosceles triangles, and by the equality of the base angles of an isosceles triangle, ∠ OBC = ∠ OCB and ∠ OBA = ∠ OAB .
Let α = ∠ BAO and β = ∠ OBC . The three internal angles of the ∆ ABC triangle are α , ( α + β ) , and β . Since the sum of the angles of a triangle is equal to 180°, we have
Q.E.D.
The theorem may also be proven using trigonometry : Let O = (0, 0) , A = (−1, 0) , and C = (1, 0) . Then B is a point on the unit circle (cos θ , sin θ ) . We will show that △ ABC forms a right angle by proving that AB and BC are perpendicular — that is, the product of their slopes is equal to −1. We calculate the slopes for AB and BC :
Then we show that their product equals −1:
Note the use of the Pythagorean trigonometric identity sin 2 θ + cos 2 θ = 1. {\displaystyle \sin ^{2}\theta +\cos ^{2}\theta =1.}
Let △ ABC be a triangle in a circle where AB is a diameter in that circle. Then construct a new triangle △ ABD by mirroring △ ABC over the line AB and then mirroring it again over the line perpendicular to AB which goes through the center of the circle. Since lines AC and BD are parallel , likewise for AD and CB , the quadrilateral ACBD is a parallelogram . Since lines AB and CD , the diagonals of the parallelogram, are both diameters of the circle and therefore have equal length, the parallelogram must be a rectangle. All angles in a rectangle are right angles.
The theorem can be proved using vector algebra. Let's take the vectors A B → {\displaystyle {\overrightarrow {AB}}} and C B → {\displaystyle {\overrightarrow {CB}}} . These vectors satisfy
and their dot product can be expanded as
but
and the dot product vanishes
and then the vectors A B → {\displaystyle {\overrightarrow {AB}}} and C B → {\displaystyle {\overrightarrow {CB}}} are orthogonal and the angle ABC is a right angle.
For any triangle, and, in particular, any right triangle, there is exactly one circle containing all three vertices of the triangle. This circle is called the circumcircle of the triangle.
The locus of points equidistant from two given points is a straight line that is called the perpendicular bisector of the line segment connecting the points. The perpendicular bisectors of any two sides of a triangle intersect in exactly one point. This point must be equidistant from the vertices of the triangle.
One way of formulating Thales's theorem is: if the center of a triangle's circumcircle lies on the triangle then the triangle is right, and the center of its circumcircle lies on its hypotenuse.
The converse of Thales's theorem is then: the center of the circumcircle of a right triangle lies on its hypotenuse. (Equivalently, a right triangle's hypotenuse is a diameter of its circumcircle.)
This proof consists of 'completing' the right triangle to form a rectangle and noticing that the center of that rectangle is equidistant from the vertices and so is the center of the circumscribing circle of the original triangle, it utilizes two facts:
Let there be a right angle ∠ ABC , r a line parallel to BC passing by A , and s a line parallel to AB passing by C . Let D be the point of intersection of lines r and s . (It has not been proven that D lies on the circle.)
The quadrilateral ABCD forms a parallelogram by construction (as opposite sides are parallel). Since in a parallelogram adjacent angles are supplementary (add to 180°) and ∠ ABC is a right angle (90°) then angles ∠ BAD , ∠ BCD , ∠ ADC are also right (90°); consequently ABCD is a rectangle.
Let O be the point of intersection of the diagonals AC and BD . Then the point O , by the second fact above, is equidistant from A , B , and C . And so O is center of the circumscribing circle, and the hypotenuse of the triangle ( AC ) is a diameter of the circle.
Given a right triangle ABC with hypotenuse AC , construct a circle Ω whose diameter is AC . Let O be the center of Ω . Let D be the intersection of Ω and the ray OB . By Thales's theorem, ∠ ADC is right. But then D must equal B . (If D lies inside △ ABC , ∠ ADC would be obtuse, and if D lies outside △ ABC , ∠ ADC would be acute.)
This proof utilizes two facts:
Let there be a right angle ∠ ABC and circle M with AC as a diameter.
Let M's center lie on the origin, for easier calculation.
Then we know
It follows
This means that A and B are equidistant from the origin, i.e. from the center of M . Since A lies on M , so does B , and the circle M is therefore the triangle's circumcircle.
The above calculations in fact establish that both directions of Thales's theorem are valid in any inner product space .
As stated above, Thales's theorem is a special case of the inscribed angle theorem (the proof of which is quite similar to the first proof of Thales's theorem given above):
A related result to Thales's theorem is the following:
Thales's theorem can be used to construct the tangent to a given circle that passes through a given point. In the figure at right, given circle k with centre O and the point P outside k , bisect OP at H and draw the circle of radius OH with centre H . OP is a diameter of this circle, so the triangles connecting OP to the points T and T′ where the circles intersect are both right triangles.
Thales's theorem can also be used to find the centre of a circle using an object with a right angle, such as a set square or rectangular sheet of paper larger than the circle. [ 7 ] The angle is placed anywhere on its circumference (figure 1). The intersections of the two sides with the circumference define a diameter (figure 2). Repeating this with a different set of intersections yields another diameter (figure 3). The centre is at the intersection of the diameters. | https://en.wikipedia.org/wiki/Thales's_theorem |
Thalidomide , sold under the brand names Contergan and Thalomid among others, is an oral medication used to treat a number of cancers (e.g., multiple myeloma ), graft-versus-host disease , and many skin disorders (e.g., complications of leprosy such as skin lesions ). [ 6 ] [ 7 ] Thalidomide has been used to treat conditions associated with HIV : aphthous ulcers , HIV-associated wasting syndrome , diarrhea, and Kaposi's sarcoma , but increases in HIV viral load have been reported. [ 6 ]
Common side effects include sleepiness , rash , and dizziness . [ 6 ] Severe side effects include tumor lysis syndrome , blood clots , and peripheral neuropathy . [ 8 ] Thalidomide is a known human teratogen and carries an extremely high risk of severe, life-threatening birth defects if administered or taken during pregnancy. [ 6 ] It causes skeletal deformities such as amelia (absence of legs and/or arms), absence of bones, and phocomelia (malformation of the limbs). A single dose of thalidomide, regardless of dosage, is enough to cause teratogenic effects. [ 6 ]
Thalidomide was first marketed in 1957 in West Germany, where it was available over-the-counter . [ 9 ] [ 10 ] When first released, thalidomide was promoted for anxiety , trouble sleeping , "tension", and morning sickness . [ 10 ] [ 11 ] While it was initially thought to be safe in pregnancy, Thalidomide was found to cause birth defects , resulting in its removal from the market in Europe in 1961. [ 9 ] [ 10 ] The total number of infants severely harmed by thalidomide use during pregnancy is estimated at over 10,000, possibly 20,000, of whom about 40% died around the time of birth. [ 6 ] [ 10 ] Those who survived had limb, eye, urinary tract, and heart problems. [ 9 ] Its initial entry into the US market was prevented by Frances Kelsey , a reviewer at the FDA. [ 11 ] The birth defects caused by thalidomide led to the development of greater drug regulation and monitoring in many countries. [ 9 ] [ 11 ]
It was approved in the United States in 1998 for use as a treatment for cancer. [ 6 ] It is on the World Health Organization's List of Essential Medicines . [ 12 ] It is available as a generic medication . [ 8 ] [ 13 ]
Thalidomide is used as a first-line treatment for multiple myeloma in combination with dexamethasone or with melphalan and prednisone to treat acute episodes of erythema nodosum leprosum , as well as for maintenance therapy. [ 14 ] [ 15 ]
The bacterium that causes tuberculosis (TB) is related to leprosy . Thalidomide may be helpful in some cases where standard TB drugs and corticosteroids are not sufficient to resolve severe inflammation in the brain. [ 16 ] [ 17 ]
It is used as a second-line treatment to manage graft-versus-host disease and aphthous stomatitis in children and has been prescribed for other conditions in children, including actinic prurigo and epidermolysis bullosa ; the evidence for these uses is weak. [ 18 ] It is recommended only as a third line treatment in graft-versus-host-disease in adults because of lack of efficacy and side effects observed in clinical trials. [ 19 ] [ 20 ]
Prescriptions of thalidomide are accompanied by strict measures to avoid any possibility of use during pregnancy, and thalidomide should be avoided in women wanting to conceive. [ 21 ] In the United States, the prescribing doctor is required to ensure that contraception is being used and that regular pregnancy tests are taken. [ 15 ] [ 14 ]
Thalidomide causes birth defects . [ 14 ] [ 15 ] [ 22 ] [ 23 ] The U.S. Food and Drug Administration (FDA) and other regulatory agencies have approved marketing of the drug only with an auditable risk evaluation and mitigation strategy that ensures that people using the drug are aware of the risks and avoid pregnancy; this applies to both men and women, as the drug can be transmitted in semen . [ 22 ] [ failed verification ] [ 21 ]
There is a high risk that thalidomide can cause excessive blood clots . There is also a high risk that thalidomide can interfere with the production of several types of new blood cells, creating a risk of infection via neutropenia , leukopenia , and lymphopenia , and risks that blood will not clot via thrombocytopenia . There is also a risk of anemia via lack of red blood cells. The drug can also damage nerves, causing potentially irreversible peripheral neuropathy . [ 14 ] [ 15 ]
Thalidomide has several adverse cardiovascular effects, including risk of heart attacks , pulmonary hypertension , and changes in heart rhythm, such as syncope , bradycardia , and atrioventricular block . [ 14 ] [ 15 ]
Thalidomide can cause liver damage and severe skin reactions like Stevens–Johnson syndrome . It tends to make people sleepy, which creates risk when driving and operating other machinery. As it kills cancer cells, it can cause tumor lysis syndrome . Thalidomide can prevent menstruation . [ 14 ] [ 15 ]
In addition, very common (reported in more than 10% of people) adverse effects include tremor , dizziness, tingling, numbness, constipation, and peripheral edema . [ 14 ] [ 15 ]
Common adverse effects (reported by 1–10% of people) include confusion, depressed mood, reduced coordination, heart failure, difficulty breathing, interstitial lung disease, lung inflammation, vomiting, dry mouth, rashes, dry skin, fever, weakness, and a sense of unwellness. [ 14 ] [ 15 ]
There are no expected pharmacokinetic interactions between thalidomide and other medicines due to its neutral effects on P-glycoprotein and the cytochrome P450 family. It may interact with sedatives due to its sedative action and bradycardic agents, like beta-blockers, due to its bradycardia-inducing effects. The risk of peripheral neuropathy may be increased by concomitant treatment of thalidomide with other agents known to cause peripheral neuropathy. [ 24 ] The risk of venous thromboembolisms with thalidomide seems to be increased when patients are treated with oral contraceptives or other cytotoxic agents (including doxorubicin and melphalan ) concurrently. Thalidomide may interfere with various contraceptives, and hence it is advised that women of reproductive age use at least two different means of contraception to ensure that no child will be conceived while they are taking thalidomide. [ 14 ] [ 15 ] [ 24 ]
As of 2013, eighteen cases of overdoses had been reported with doses of up to 14.4 grams, none of them fatal. [ 24 ] No specific antidote for overdose exists and treatment is purely supportive . [ 24 ]
The precise mechanism of action for thalidomide was not known until the twenty-first century, [ 25 ] although efforts to identify thalidomide's teratogenic action generated more than 2,000 research papers and the proposal of 15 or 16 plausible mechanisms by 2000. [ 26 ] The primary mechanism of action of thalidomide and its analogs in both their anti-cancer and teratogenic effects is now known to be as cereblon E3 ligase modulators. [ 25 ] [ 27 ] [ 28 ] [ 29 ]
Thalidomide also binds to and acts as an antagonist of the androgen receptor and hence is a nonsteroidal antiandrogen of some capacity. [ 30 ] In accordance, it can produce gynecomastia and sexual dysfunction as side effects in men. [ 31 ]
Thalidomide is provided as a racemic mixture of two enantiomers ; while there are reports that only one of the enantiomers may cause birth defects, the body converts each enantiomer into the other through mechanisms that are not well understood. [ 22 ] The (R)-enantiomer has the desired sedative effect while the (S)-enantiomer harbors embryo-toxic and teratogenic effects. Attempting to extract solely R -thalidomide does not remove the risk of birth defects, as it was demonstrated that the "safe" R -thalidomide undergoes an in vivo chiral inversion to the "teratogenic" S -thalidomide. Under biological conditions, the enantiomers interconvert ( bidirectional chiral inversion – (R)- to (S)- and vice versa). [ 32 ] [ 33 ]
Thalidomide is racemic ; while S -thalidomide is the bioactive form of the molecule, the individual enantiomers can racemize to each other due to the acidic hydrogen at the chiral centre , which is the carbon of the glutarimide ring bonded to the phthalimide substituent . The racemization process can occur in vivo . [ 5 ] [ 34 ] [ 35 ] [ 36 ] The process of conversion of one enantiomer to its mirror-image version with no other change in the molecule is called chiral inversion. [ 37 ]
Celgene Corporation originally synthesized thalidomide using a three-step sequence starting with L -glutamic acid treatment, but this has since been reformed by the use of L -glutamine . [ 38 ] As shown in the image below, N -carbethoxyphthalimide (1) can react with L -glutamine to yield N -phthaloyl- L -glutamine (2). Cyclization of N -phthaloyl- L -glutamine occurs using carbonyldiimidazole , which then yields thalidomide (3). [ 38 ] Celgene Corporation's original method resulted in a 31% yield of S -thalidomide, whereas the two-step synthesis yields 85–93% product that is 99% pure. [ citation needed ]
In 2023, it is reported that phthalic anhydride and L -glutamine under suitable conditions can react directly to form thalidomide. In the procedure, phthalic anhydride and L -glutamine are grounded and added into toluene solvent. The solution, along with triethylamine and acetic anhydride , is refluxed at ~110°C for 9 hours; after that the solution goes through a simple vacuum filtration procedure to obtain the product. [ 39 ]
In 1952, thalidomide was synthesised by Chemical Industry Basel , but was found "to have no effect on animals" and was discarded on that basis. [ 40 ] In 1957, it was acquired by Chemie Grünenthal in Germany. [ 40 ] The German company had been established as a soap maker after World War II ended, to address the urgent market need for antibiotics. [ 41 ] Heinrich Mückter [ 42 ] was appointed to head the discovery program based on his experience working with the German army's antiviral research. While preparing reagents for the work, Mueckter's assistant Wilhelm Kunz isolated a by-product that was recognized by pharmacologist Herbert Keller as an analog of glutethimide , a sedative . The medicinal chemistry work turned to improving the lead compound into a suitable drug: the result was thalidomide. The toxicity was examined in several animals, and the drug was introduced in 1956 as a sedative, but it was never tested on pregnant women. [ 43 ]
Researchers at Chemie Grünenthal found that thalidomide was a particularly effective antiemetic that had an inhibitory effect on morning sickness . [ 44 ] On 1 October 1957, the company launched thalidomide and began marketing it under the trade name Contergan. [ 45 ] [ 46 ] It was proclaimed a "wonder drug" for insomnia , coughs, colds and headaches. [ 47 ]
During that period, the use of medications during pregnancy was not strictly controlled, and drugs were not thoroughly tested for potential harm to the fetus . [ 44 ] Thousands of pregnant women took the drug to relieve their symptoms. At the time of the drug's development, scientists did not believe any drug taken by a pregnant woman could pass across the placental barrier and harm the developing fetus. [ 48 ] There soon appeared reports of abnormalities in children being born to mothers using thalidomide. In late 1959, it was noticed that peripheral neuritis developed in patients who took the drug over a period of time, and it was only after this point that thalidomide ceased to be provided over the counter. [ 49 ]
While initially considered safe, the drug was responsible for teratogenic deformities in children born after their mothers used it during pregnancies, prior to the third trimester. In November 1961, thalidomide was taken off the market due to massive pressure from the press and public. [ 50 ] Experts estimate that thalidomide led to the death of approximately 2,000 children and serious birth defects in more than 10,000 children, with over half of them in West Germany. [ 51 ] The regulatory authorities in East Germany never approved thalidomide. [ 52 ] One reason for the initially unobserved side effects of the drug and the subsequent approval in West Germany was that at that time drugs did not have to be tested for teratogenic effects. They were tested for toxicity on rodents only, as was usual at the time. [ 53 ]
In the UK, the British pharmaceutical company The Distillers Company (Biochemicals) Ltd, a subsidiary of Distillers Co. Ltd (now part of Diageo plc ), marketed thalidomide throughout the UK, Australia, and New Zealand, under the brand name Distaval, as a remedy for morning sickness . Their advertisement claimed that "Distaval can be given with complete safety to pregnant women and nursing mothers without adverse effect on mother or child ... Outstandingly safe Distaval has been prescribed for nearly three years in this country." [ 52 ] Globally, more pharmaceutical companies started to produce and market the drug under license from Chemie Grünenthal. Thalidomide was available in 46 countries under many different brand names. [ 54 ]
In the US, representatives from Chemie Grünenthal approached Smith, Kline & French (SKF), now GlaxoSmithKline , with a request to market and distribute the drug in North America. A memorandum, rediscovered in 2010 in the archives of the FDA, shows that in 1956–57, as part of its in-licensing approach, Smith, Kline and French conducted animal tests and ran a clinical trial of the drug in the US involving 875 people, including pregnant women. [ 55 ] In 1956, researchers involved in clinical trials at SKF noted that, even when used in very high doses, thalidomide could not induce sleep in mice. [ 56 ] When administered at doses 50 to 650 times larger than that claimed by Chemie Grünenthal to be "sleep-inducing", the researchers could still not achieve the hypnotic effect in animals that it had on humans. [ citation needed ] After completion of the trial, and based on reasons kept hidden for decades, SKF declined to commercialize the drug. In 1958, Chemie Grünenthal reached an agreement with the William S. Merrell Company in Cincinnati, Ohio ( later Richardson-Merrell , now part of Sanofi ), to market and distribute thalidomide throughout the US. [ 52 ]
The US FDA refused to approve thalidomide for marketing and distribution. However, the drug was distributed in large quantities for testing purposes, after the American distributor and manufacturer Richardson-Merrell had applied for its approval in September 1960. [ 57 ] The official in charge of the FDA review, Frances Oldham Kelsey , did not rely on information from the company, which did not include any test results. Richardson-Merrell was called on to perform tests and report the results. The company demanded approval six times and was refused each time. The distribution for "testing" resulted in 17 children born in the US with thalidomide-induced malformations. Oldham Kelsey was awarded the President's Award for Distinguished Federal Civilian Service by President Kennedy in 1962 for not allowing thalidomide to be approved for sale in the US. She was also inducted into the National Women's Hall of Fame in 2000. [ 58 ]
Canada's Food and Drug Directorate approved the sale of thalidomide by prescription in November 1960. [ 59 ] There were many different forms sold: Kevadon, produced by the William S. Merrell Company seeking approval for its thalidomide product, was released on the market in April 1961, and the most common variant (Horner's Talimol) was put on the market on October 23 of the same year. [ 60 ] Two months after Talimol went on sale, pharmaceutical companies sent physicians letters warning about the risk of birth defects. [ 60 ] It was not until March 1962 that both drugs were banned from the Canadian market by the directorate, and soon afterward physicians were warned to destroy their supplies. [ 60 ]
In 1964, Israeli physician Jacob Sheskin administered thalidomide to a patient critically ill with leprosy . The patient exhibited erythema nodosum leprosum (ENL), a painful skin condition, one of the complications of leprosy. The treatment was attempted despite the ban on thalidomide's use, and the results were favourable: the patient slept for hours and was able to get out of bed without aid upon awakening. A clinical trial studying the use of thalidomide in leprosy soon followed. [ 61 ]
Thalidomide has been used by Brazilian physicians as the drug of choice for the treatment of severe ENL since 1965, and by 1996, at least 33 cases of thalidomide embryopathy were recorded in people born in Brazil after 1965. [ 62 ] Since 1994, the production, dispensing, and prescription of thalidomide have been strictly controlled, requiring women to use two forms of birth control and submit to regular pregnancy tests. Despite this, cases of thalidomide embryopathy continue, [ 63 ] [ 64 ] with at least 100 cases identified in Brazil between 2005 and 2010. [ 65 ] Nearly 6 million thalidomide pills were distributed throughout Brazil in this time period, and these cases have occurred despite the controls. [ 66 ]
In 1998, the FDA approved the drug's use in the treatment of ENL. [ 67 ] Because of thalidomide's potential for causing birth defects, the drug may be distributed only under tightly controlled conditions. The FDA required that Celgene Corporation , which planned to market thalidomide under the brand name Thalomid , establish a system for thalidomide education and prescribing safety (STEPS) oversight program. The conditions required under the program include limiting prescription and dispensing rights to authorized prescribers and pharmacies only, keeping a registry of all patients prescribed thalidomide, providing extensive patient education about the risks associated with the drug, and providing periodic pregnancy tests for women who take the drug. [ 67 ]
In 2010, the World Health Organization stated that it did not recommend thalidomide for leprosy due to the difficulty of adequately controlling its use, and due to the availability of clofazimine . [ 68 ]
Shortly after the teratogenic properties of thalidomide were recognized in the mid-1960s, its anti-cancer potential was explored and two clinical trials were conducted in people with advanced cancer, including some people with multiple myeloma; the trials were inconclusive. [ 69 ]
Little further work was done with thalidomide in cancer until the 1990s. [ 69 ]
Judah Folkman pioneered studies into the role of angiogenesis (the proliferation and growth of blood vessels) in the development of cancer, and in the early 1970s had shown that solid tumors could not expand without it. [ 70 ] [ 71 ] In 1993 he surprised the scientific world by hypothesizing the same was true of blood cancers , [ 72 ] and the next year he published work showing that a biomarker of angiogenesis was higher in all people with cancer, but especially high in people with blood cancers, and other evidence emerged as well. [ 73 ] Meanwhile, a member of his lab, Robert D'Amato, who was looking for angiogenesis inhibitors , discovered in 1994 that thalidomide inhibited angiogenesis [ 74 ] and was effective in suppressing tumor growth in rabbits. [ 75 ] Around that time, the wife of a man who was dying of multiple myeloma and whom standard treatments had failed, called Folkman asking him about his anti-angiogenesis ideas. [ 71 ] Folkman persuaded the patient's doctor to try thalidomide, and that doctor conducted a clinical trial of thalidomide for people with multiple myeloma in which about a third of the subjects responded to the treatment. [ 71 ] The results of that trial were published in the New England Journal of Medicine in 1999. [ 71 ] [ 76 ]
After further work was done by Celgene and others, in 2006 the US Food and Drug Administration granted accelerated approval for thalidomide in combination with dexamethasone for the treatment of newly diagnosed multiple myeloma patients. [ 71 ] [ 77 ]
It was also evaluated whether thalidomide can be combined with melphalan and prednisone for patients with multiple myeloma. This combination of drugs probably increases the overall survival. [ 78 ]
In the late 1950s and early 1960s, more than 10,000 children in 46 countries were born with deformities, such as phocomelia , as a consequence of thalidomide use. [ 79 ] The severity and location of the deformities depended on how many days into the pregnancy the mother was before beginning treatment, with the time-sensitive window occurring approximately between day 20 and day 36 post-fertilisation. [ 51 ] Thalidomide taken on the 20th day of pregnancy caused central brain damage, day 22 the ears and face, day 24 the arms, and leg damage would occur if taken up to day 28. [ 80 ]
It is not known exactly how many worldwide victims of the drug there have been, although estimates range from 10,000 to 20,000. [ 81 ] Despite the side effects, thalidomide was sold in pharmacies in Canada until 1962. [ 60 ] [ 82 ]
The disaster prompted many countries to introduce tougher rules for the testing and licensing of drugs, such as the 1962 Kefauver Harris Amendment [ 91 ] (US), 1965 Directive 65/65/EEC1 (EU), [ 92 ] and the Medicines Act 1968 (UK). [ 93 ] [ 94 ] In the United States, the new regulations strengthened the FDA, among other ways, by requiring applicants to prove efficacy and to disclose all side effects encountered in testing. [ 79 ] The FDA subsequently initiated the Drug Efficacy Study Implementation to reclassify drugs already on the market. [ 95 ]
In 1977 the US Federal Drug Administration published a clinical trial guideline that excluded women of "childbearing potential" from the early phases of most clinical trials, which in practice led to their exclusion from later trial phases as well. [ 96 ] This 1977 FDA guideline was implemented in response to a protectionist climate caused by the thalidomide tragedy. [ 96 ] In the 1980s, a US task force on women's health concluded that a lack of women's health research (in part due to the FDA guideline) had compromised the amount and quality of information available about diseases and treatments affecting women. [ 96 ] This led to the National Institute of Health policy that women should, when beneficial, be included in clinical trials. [ 96 ]
In the 1960s, thalidomide was successfully marketed as a safer alternative to barbiturates . Due to a successful marketing campaign, thalidomide was widely used by pregnant women during the first trimester of pregnancy. However, thalidomide is a teratogenic substance, and a proportion of children born during the 1960s had thalidomide embryopathy (TE). [ 97 ] Of these babies born with TE, "about 40% of them died before their first birthday". [ 98 ] The surviving individuals are now middle-aged and they report experiencing challenges (physical, psychological, and socioeconomic) related to TE. [ 99 ] [ 100 ]
Individuals born with TE frequently experience a wide variety of health problems secondary to their TE. These health conditions include both physical and psychological conditions. When compared to individuals of similar demographic profiles, those born with TE report less satisfaction with their quality of life and their overall health. [ 97 ] Access to healthcare services can also be a challenge for these people, and women, in particular, have experienced difficulty in locating healthcare professionals who can understand and embrace their needs. [ 98 ]
Brand names include Contergan, Thalomid, Talidex, Talizer, Neurosedyn, Distaval, and many others. [ 7 ]
Research efforts have been focused on determining how thalidomide causes birth defects and its other activities in the human body, efforts to develop safer analogs, and efforts to find further uses for thalidomide. [ 101 ]
The exploration of the antiangiogenic and immunomodulatory activities of thalidomide has led to the study and creation of thalidomide analogs . [ 102 ] [ 103 ] Celgene has sponsored numerous clinical trials with analogues to thalidomide, such as lenalidomide , that are substantially more powerful and have fewer side effects — except for greater myelosuppression . [ 104 ] In 2005, Celgene received FDA approval for lenalidomide (Revlimid) as the first commercially useful derivative. Revlimid is available only in a restricted distribution setting to avoid its use during pregnancy. Further studies are being conducted to find safer compounds with useful qualities. Another more potent analog, pomalidomide , is now FDA-approved. [ 105 ] Additionally, apremilast was approved by the FDA in March 2014. These thalidomide analogs can be used to treat different diseases, or used in a regimen to fight two conditions. [ 106 ]
Interest turned to pomalidomide , a derivative of thalidomide marketed by Celgene . It is a very active anti-angiogenic agent [ 103 ] and also acts as an immunomodulator . Pomalidomide was approved in February 2013 by the FDA as a treatment for relapsed and refractory multiple myeloma . [ 107 ] It received a similar approval from the European Commission in August 2013, and is expected to be marketed in Europe under the brand name Imnovid . [ 108 ]
There is no conclusive evidence that thalidomide or lenalidomide is useful to bring about or maintain remission in Crohn's disease. [ 109 ] [ 110 ]
Thalidomide was studied in a Phase II trial for Kaposi's sarcoma , a rare soft-tissue cancer most commonly seen in the immunocompromised, that is caused by the Kaposi's sarcoma-associated herpesvirus (KSHV). [ 111 ] [ 44 ] | https://en.wikipedia.org/wiki/Thalidomide |
In the late 1950s and early 1960s, the use of thalidomide in 46 countries was prescribed to women who were pregnant or who subsequently became pregnant, and consequently resulted in the "biggest anthropogenic medical disaster ever," with more than 10,000 children born with a range of severe deformities, such as phocomelia , as well as thousands of miscarriages. [ 1 ] [ 2 ]
Thalidomide was introduced in 1957 as a tranquilizer, and was later marketed by the German pharmaceutical company Chemie Grünenthal under the trade name Contergan as a medication for anxiety , trouble sleeping , tension, and morning sickness . [ 3 ] [ 4 ] It was introduced as a sedative and medication for morning sickness without having been tested on pregnant women. [ 5 ] While initially deemed to be safe in pregnancy, concerns regarding birth defects were noted in 1961, and the medication was removed from the market in Europe that year. [ 3 ] [ 6 ]
Thalidomide was first developed as a tranquilizer by Swiss pharmaceutical company Ciba in 1953.
In 1954, Ciba abandoned the product, and it was acquired by German pharmaceutical company Chemie Grünenthal . [ 4 ] The company had been established by Hermann Wirtz Sr, a Nazi Party member, after World War II as a subsidiary of the family's Mäurer & Wirtz company. The company's initial aim was to develop antibiotics for which there was an urgent market need. Wirtz appointed chemist Heinrich Mückter , who had escaped prosecution for war crimes for his experiments on prisoners of Nazi concentration camps , to head the development programme because of his experience researching and producing an anti-typhus vaccine for Nazi Germany . [ 7 ] He hired Martin Staemmler, a medical doctor and leading proponent of the Nazi eugenics programme, as head of pathology, as well as Heinz Baumkötter , the chief medical officer at the Sachsenhausen concentration camp , and Otto Ambros , a chemist and Nazi war criminal. Ambros was the chairman of Grünenthal's advisory committee during the development of thalidomide and was a board member when Contergan was being sold. [ 8 ]
The total number of embryos affected by the use of thalidomide during pregnancy is estimated at more than 10,000, and potentially up to 20,000; of these, approximately 40 percent died at or shortly after the time of birth. [ 3 ] [ 9 ] [ 10 ] Those who survived had limb, eye, urinary tract, and heart defects. [ 6 ] Its initial entry into the U.S. market was prevented by Frances Oldham Kelsey at the U.S. Food and Drug Administration (FDA). [ 4 ] The birth defects of thalidomide led to the development of greater drug regulation and monitoring in many countries. [ 4 ] [ 6 ]
The severity and location of the deformities depended on how many days into the pregnancy the mother was before beginning treatment; thalidomide taken on the 20th day of pregnancy caused central brain damage, day 21 would damage the eyes, day 22 the ears and face, day 24 the arms, and leg damage would occur if taken up to day 28. Thalidomide did not damage the fetus if taken after 42 days' gestation. [ 11 ] [ 12 ]
In the UK, the drug was licensed in 1958 and withdrawn in 1961. Of the approximately 2,000 babies born with defects, around half died within a few months and 466 survived to at least 2010. [ 13 ] In 1968, after a long campaign by The Sunday Times , a compensation settlement for the UK victims was reached with Distillers Company (now part of Diageo ), which had distributed the drug in the UK. [ 14 ] [ 15 ] Distillers Biochemicals paid out approximately £28m in compensation following a legal battle. [ 16 ]
The British Thalidomide Children's Trust was set up in 1973 as part of a £20 million legal settlement between Distillers Company and 429 children with thalidomide-related disabilities. In 1997, Diageo (formed by a merger between Grand Metropolitan and Guinness, who had taken over Distillers in 1990) made a long-term financial commitment to support the Thalidomide Trust and its beneficiaries. [ 17 ] The UK government gave survivors a grant of £20 million, to be distributed through the Thalidomide Trust, in December 2009. [ 16 ]
In Spain, thalidomide was widely available throughout the 1970s, and perhaps even into the 1980s. There were two reasons for this. First, state controls and safeguarding were poor; it was not until 2008 that the government even admitted the country had ever imported thalidomide. Second, Grünenthal failed to insist that its sister company in Madrid warn Spanish doctors, and permitted its sister company not to warn doctors of the defects. The Spanish advocacy group for victims of thalidomide estimates that in 2015, there were 250–300 living victims of thalidomide in Spain. [ 18 ]
Although the Australian obstetrician William McBride took credit for raising concern about thalidomide, it was a midwife called Sister Pat Sparrow who first suspected the drug was causing birth defects in the babies of patients under McBride's care at Crown Street Women's Hospital in Sydney. [ 19 ] German paediatrician Widukind Lenz , who also suspected the link, is credited with conducting the scientific research that proved thalidomide was causing birth defects in 1961. [ 20 ] [ 21 ] McBride was later awarded a number of honors, including a medal and prize money by L'Institut de la Vie in Paris, [ 22 ] but he was eventually struck off the Australian medical register in 1993 for scientific fraud related to work on Debendox . [ 19 ] [ 23 ] Further animal tests were conducted by George Somers, Chief Pharmacologist of Distillers Company in Britain, which showed fetal abnormalities in rabbits. [ 24 ] Similar results were also published showing these effects in rats [ 25 ] [ 26 ] and other species. [ 27 ]
Lynette Rowe, who was born without limbs, led an Australian class action lawsuit against the drug's manufacturer, Grünenthal, which fought to have the case heard in Germany. The Supreme Court of Victoria dismissed Grünenthal's application in 2012, and the case was heard in Australia. [ 28 ] On 17 July 2012, Rowe was awarded an out-of-court settlement , believed to be in the millions of dollars and providing precedence for class action victims to receive further compensation. [ 29 ] In February 2014, the Supreme Court of Victoria endorsed the settlement of $89 million AUD to 107 victims of the drug in Australia and New Zealand. [ 30 ] [ 31 ]
In East Germany , thalidomide was rejected by the Central Committee of Experts for the Drug Traffic in the GDR, and was never approved for use. There are no known thalidomide babies born in East Germany. [ 32 ] Meanwhile, in West Germany , it took some time before the increase in dysmelia at the end of the 1950s was connected with thalidomide. In 1958, Karl Beck, a former pediatric doctor in Bayreuth , wrote an article in a local newspaper claiming a relationship between nuclear weapons testing and cases of dysmelia in children. [ 33 ] Based on this, FDP whip Erich Mende requested an official statement from the federal government. [ 33 ] For statistical reasons, the main data series used to research dysmelia cases started by chance at the same time as the approval date for thalidomide. [ 33 ] After the Nazi regime with its Law for the Prevention of Hereditarily Diseased Offspring used mandatory statistical monitoring to commit various crimes , western Germany had been very reluctant to monitor congenital disorders in a similarly strict way. [ 34 ] The parliamentary report rejected any relation with radioactivity and the abnormal increase of dysmelia. [ 33 ] Also the DFG research project installed after the Mende request was not helpful. The project was led by pathologist Franz Büchner , who ran the project to propagate his teratological theory. Büchner saw lack of healthy nutrition and behavior of the mothers as being more important than genetic reasons. [ 34 ] Furthermore, it took a while to appoint a Surgeon General in Germany; the Federal Ministry of Health was not founded until 1962, some months after thalidomide was banned from the market. [ 33 ] In West Germany approximately 2,500 babies were born with birth defects from thalidomide. [ 21 ]
Despite its severe side effects, thalidomide was sold in pharmacies in Canada until 1962. [ 35 ] [ 36 ] The effects of thalidomide increased fears regarding the safety of pharmaceutical drugs. The Society of Toxicology of Canada was formed after the effects of thalidomide were made public, focusing on toxicology as a discipline separate from pharmacology. [ 37 ] The need for the testing and approval of the toxins in certain pharmaceutical drugs became more important after the disaster. The Society of Toxicology of Canada is responsible for the Conservation Environment Protection Act, focusing on researching the impact to human health of chemical substances. [ 37 ] Thalidomide brought on changes in the way drugs are tested, what type of drugs are used during pregnancy, and increased the awareness of potential side effects of drugs.
According to Canadian news magazine programme W5 , most, but not all, victims of thalidomide receive annual benefits as compensation from the Government of Canada . Excluded are those who cannot provide the documentation the government requires. [ 38 ]
A group of 120 Canadian survivors formed the Thalidomide Victims Association of Canada, the goal of which is to prevent the approval of drugs that could be harmful to pregnant individuals and babies. [ 39 ] [ 40 ] The members from the thalidomide victims association were involved in the STEPS programme, which aimed to prevent teratogenicity . [ 41 ]
In the U.S., the FDA refused approval to market thalidomide, saying further studies were needed. This reduced the impact of thalidomide in U.S. patients. The refusal was largely due to pharmacologist Frances Oldham Kelsey who withstood pressure from the Richardson-Merrell Pharmaceuticals Co. Although thalidomide was not approved for sale in the United States at the time, over 2.5 million tablets had been distributed to over 1,000 physicians during a clinical testing programme. It is estimated that nearly 20,000 patients, several hundred of whom were pregnant, were given the drug to help alleviate morning sickness or as a sedative, and at least 17 children were consequently born in the United States with thalidomide-associated deformities. [ 42 ] [ 43 ] While pregnant, children's television host Sherri Finkbine took thalidomide that her husband had purchased over-the-counter in Europe. [ 44 ] When she learned that thalidomide was causing fetal deformities she wanted to abort her pregnancy, but the laws of Arizona allowed abortion only if the mother's life was in danger. Finkbine traveled to Sweden to have the abortion. Thalidomide was found to have deformed the fetus. [ 42 ]
For denying the application despite the pressure from Richardson-Merrell Pharmaceuticals Co., Kelsey eventually received the President's Award for Distinguished Federal Civilian Service at a 1962 ceremony with President John F. Kennedy . [ 2 ] In September 2010, the FDA honored Kelsey with the first Kelsey award, given annually to an FDA staff member. This came 50 years after Kelsey, then a new medical officer at the agency, first reviewed the application from the William S. Merrell Pharmaceuticals Company of Cincinnati. [ 45 ]
Cardiologist Helen B. Taussig learned of the damaging effects of the drug thalidomide on newborns and in 1967, testified before Congress on this matter after a trip to Germany where she worked with infants with phocomelia (severe limb deformities). As a result of her efforts, thalidomide was banned in the United States and Europe. [ 46 ]
Ingeborg Eichler, a member of the Austrian pharmaceutical admission conference, enforced restrictions on the sale of thalidomide (tradename Softenon) under the rules of prescription medication and as a result relatively few affected children were born in Austria and Switzerland. [ 47 ]
The numerous reports of malformations in babies brought about the awareness of the side effects of the drug on pregnant women. The birth defects caused by the drug thalidomide can range from moderate malformation to more severe forms. Possible birth defects include phocomelia , dysmelia , amelia , bone hypoplasticity , and other congenital defects affecting the ear, heart, or internal organs. [ 41 ] Franks et al. looked at how the drug affected newborn babies, the severity of their deformities, and reviewed the drug in its early years. Webb in 1963 also reviewed the history of the drug and the different forms of birth defects it had caused. "The most common form of birth defects from thalidomide is shortened limbs, with the arms being more frequently affected. This syndrome is the presence of deformities of the long bones of the limbs resulting in shortening and other abnormalities." [ 35 ]
In 1968, a large criminal trial began in West Germany, charging several Grünenthal officials with negligent homicide and injury. After Grünenthal settled with the victims in April 1970, the trial ended in December 1970 with no finding of guilt. As part of the settlement, Grünenthal paid 100 million DM into a special foundation; the West German government added 320 million DM. The foundation paid victims a one-time sum of 2,500–25,000 DM (depending on severity of disability) and a monthly stipend of 100–450 DM. The monthly stipends have since been raised substantially and are now paid entirely by the government (as the foundation had run out of money). Grünenthal paid another €50 million into the foundation in 2008.
On 31 August 2012, Grünenthal chief executive Harald F. Stock — who served as the chief executive officer of Grünenthal GmbH from January 2009 to May 28, 2013 — apologized for the first time for producing the drug and remaining silent about the birth defects. [ 48 ] At a ceremony, Stock unveiled a statue of a disabled child to symbolize those harmed by thalidomide and apologized for not trying to reach out to victims for over 50 years. At the time of the apology, there were between 5,000 and 6,000 people still living with Thalidomide-related birth defects. Victim advocates called the apology "insulting" and "too little, too late", and criticized the company for not compensating victims and for their claim that no one could have known the harm the drug caused, arguing that there were plenty of red flags at the time. [ 49 ]
On 13 November 2023, the Australian Government announced its intention to make a formal apology to people affected by thalidomide with the unveiling of a national memorial site. Prime Minister Anthony Albanese described the thalidomide tragedy as a “dark chapter” in Australian history, and Health Minister Mark Butler said, “While we cannot change the past or end the physical suffering, I hope these important next steps of recognition and apology will help heal some of the emotional wounds.” [ 50 ] [ 51 ]
The disaster prompted many countries to introduce tougher rules for the testing and licensing of drugs, such as the Kefauver Harris Amendment [ 58 ] (US), Directive 65/65/EEC1 (E.U.), [ 59 ] and the Medicines Act 1968 (UK). [ 60 ] [ 61 ] In the United States, the new regulations strengthened the FDA, among other ways, by requiring applicants to prove efficacy and to disclose all side effects encountered in testing. [ 2 ] The FDA subsequently initiated the Drug Efficacy Study Implementation to reclassify drugs already on the market. | https://en.wikipedia.org/wiki/Thalidomide_scandal |
Thallium(III) nitrate , also known as thallic nitrate , is a thallium compound with chemical formula Tl (NO 3 ) 3 . [ 1 ] Normally found as the trihydrate, it is a colorless and highly toxic salt which hydrolyses in water to thallium(III) oxide . [ 2 ] It is a strong oxidizing agent useful in organic synthesis .
The trihydrate is prepared by dissolving thallium(III) oxide in concentrated nitric acid at 80 °C, followed by cooling of the resulting solution: [ 3 ]
Thallium(III) nitrate trihydrate, Tl(NO 3 ) 3 ·3H 2 O, crystallizes in the hexagonal crystal system and consists of a nine-coordinate thallium center with three bidentate nitrate ligands and three monodentate water ligands. [ 4 ]
Despite its toxicity, thallium(III) nitrate is sometimes used in the laboratory, such as in the oxidation of methoxyl phenols to quinone acetals : [ 5 ]
Another use of thallium(III) nitrate is the oxidization of alkenes to acetals, cyclic alkenes to ring contracted aldehydes, and terminal alkynes to carboxylic acids . Ketones are also oxidized to carboxylic acids or esters in the presence of methanol . Illustrated below is an example of alkene oxidation to an acetal: [ 5 ] [ 6 ]
This inorganic compound –related article is a stub . You can help Wikipedia by expanding it . | https://en.wikipedia.org/wiki/Thallium(III)_nitrate |
In geography , hydrography , and fluvial geomorphology , a thalweg or talweg ( / ˈ t ɑː l v ɛ ɡ / ) is the line or curve of lowest elevation within a valley or watercourse . [ 1 ] Its vertical position in maps is the nadir (greatest depth, sounding ) in the stream profile .
Under international law , a thalweg is instead taken to be the middle of the primary navigable channel of a waterway which is the default legal presumption for the boundary between entities such as states . [ 2 ] [ 3 ] [ 4 ] Thalwegs can have local proprietorial and administrative significance because their formerly somewhat shifting position, reliant on renewed soundings, now more fixed as described internationally, is part of centuries-old custom and practice in some jurisdictions. In some jurisdictions and between some states the median line (between banks) is the preferred boundary presumption as may extend from estuaries. Also being easy to map, drawing "turning points" are the solution for a few major rivers such as the St Lawrence River -Great Lakes system. [ 5 ]
The word thalweg is of 19th-century German origin. The German word Thalweg (modern spelling Talweg ) is a compound noun that is built from the German elements Thal (since Duden 's orthography reform of 1901 written Tal ) meaning 'valley' (cognate with dale in English), and Weg , meaning 'way'. It means 'valley way' and is used, with its modern spelling Talweg , in daily German to describe a path or road which follows the bottom of a valley, or in geography with the more technical meaning also adopted by English.
In hydrological and fluvial landforms, the thalweg is a line drawn to join the lowest points along the length of a stream bed or valley in its downward slope, defining its deepest channel. The thalweg thus marks the natural direction (the profile) of a watercourse. The term is sometimes used to refer to a subterranean stream that percolates under the surface and in the same general direction as the surface stream.
Slowing stream-bed erosion by bouldering a thalweg helps stabilize natural rivers' course and depth. Placing boulders along the thalweg helps to protect the channel's sedimentary erosion and deposit balance. In concurrence with this, doing so along an instream to form artificial sills helps to slow the sedimentary erosion and deposit of watercourses, while keeping the esteem (fishing, local wildlife, and recreation) and natural resources [ 6 ] of the running water source intact. Placement of boulders along a thalweg and the creation of instream sills makes drying up rarer and less severe during late summer, and abates cases of severe sediment erosion and deposit in the spring and fall months when the flow rates are high, particularly if those rates have increased. Such partial infilling of a thalweg was prototyped in Meacham Creek in Umatilla, Oregon . [ 7 ]
The thalweg principle (also known as the thalweg doctrine or the rule of thalweg ) is the legal principle that if the boundary between two political entities is stated to be a waterway without further description ( e.g. , a median line, right bank, eastern shore, low-tide line, etc.), the boundary follows the thalweg of that watercourse. A thalweg is the center of the principal navigable channel of the waterway (which is presumed to be the deepest part). [ 8 ] If there are multiple navigable channels in a river, the one principally used for downstream travel (likely having the strongest current) is used. [ 8 ] The definition has been used in specific descriptions as well. The Treaty of Versailles , for example, specifies that "In the case of boundaries which are defined by a [navigable] waterway" the boundary is to follow "the median line of the principal channel of navigation." [ 9 ]
The precise drawing of river boundaries has been important on countless occasions. Notable examples include the Shatt al-Arab between Iraq and Iran , the Danube in central Europe ( Croatia–Serbia border dispute ), the Kasikili/Sedudu Island dispute between Namibia and Botswana (settled by the International Court of Justice in 1999), [ 10 ] and the 2004 dispute settlement under the UN Law of the Sea concerning the offshore boundary between Guyana and Suriname , in which the thalweg of the Courantyne River played a role in the ruling. [ 11 ] [ 12 ] In the 20th century dispute between the USSR and China (PRC) over Zhenbao Island , China held that the Thalweg principle supported their position. [ 13 ] The doctrine is also applied to sub-national boundaries, such as those between American states. [ 14 ] | https://en.wikipedia.org/wiki/Thalweg |
Thanatocoenosis (from Greek language thanatos - death and koinos - common) are all the embedded fossils at a single discovery site. This site may be referred to as a "death assemblage". Such groupings are composed of fossils of organisms which may not have been associated during life, often originating from different habitats. Examples include marine fossils having been brought together by a water current or animal bones having been deposited by a predator. A site containing thanatocoenosis elements can also lose clarity in its faunal history by more recent intruding factors such as burrowing microfauna or stratigraphic disturbances born from anthropogenic methods. [ 1 ]
This term differs from a related term, biocoenosis , which refers to an assemblage in which all organisms within the community interacted and lived together in the same habitat while alive. A biocoenosis can lead to a thanatocoenosis if disrupted significantly enough to have its dead/fossilized matter scattered. [ 3 ] A death community/thanatocoenosis is developed by multiple taphonomic processes (those being ones relating to the different ways in which organismal remains pass through strata and are decomposed and preserved) that are generally categorized into two groups: biostratinomy and diagenesis . As a whole, thanatocoenoses are divided into two categories as well: autochthonous and allochthonous .
Death assemblages and thanatocoenoses can provide insight into the process of early-stage fossilization, as well as information about the species within a given ecosystem. The study of taphonomy can aid in furthering the understanding of the ecological past of species and their fossil records if used in conjunction with research on death assemblages from modern ecosystems. [ 4 ]
The term "thanatocoenosis" was originally created by Erich Wasmund in 1926, and he was the first to define both the similarities and contrasts between these death communities and biocoenoses. Due to confusion between some distinctions between the two, another researcher, Horst Böger, later classified them further in 1970. Similarly to how the term " biotope " describes biocoenosis, a term analogous to thanatocoenosis, "thanatope", was also created and utilized in related literature. [ 1 ] Wasmund proffered that the terms thanatope and biotope were congruent to one another, so long as a death community is autochthonous, but that has since been refuted based on the differences regarding the formation factors involved with the two terms. [ 1 ] | https://en.wikipedia.org/wiki/Thanatocoenosis |
Thanatophages , are organisms that obtain nutrients by consuming decomposing dead plant biomass. [ 1 ]
In food webs , thanatophages generally play the roles of decomposers .
The eating of wood, whether live or dead, is known as xylophagy . The activity of animals feeding only on dead wood is called sapro-xylophagy and those animals, sapro-xylophagous.
Saprophyte ( -phyte meaning "plant") is a botanical term that is no longer in popular use, as such plants have been discovered to actually be parasitic on fungi . [ 2 ] There are no real saprotrophic organisms that are embryophytes , [ citation needed ] and fungi and bacteria are no longer placed in the plant kingdom . Plants that were once considered saprophytes, such as non-photosynthetic orchids and monotropes , are now known to be parasites on fungi. These species are now termed myco-heterotrophs . [ 3 ] [ 4 ] [ 5 ] | https://en.wikipedia.org/wiki/Thanatophage |
The thanatotranscriptome denotes all RNA transcripts produced from the portions of the genome still active or awakened in the internal organs of a body following its death . It is relevant to the study of the biochemistry , microbiology , and biophysics of thanatology , in particular within forensic science . Some genes may continue to be expressed in cells for up to 48 hours after death, producing new mRNA . Certain genes that are generally inhibited since the end of fetal development may be expressed again at this time. [ 1 ] [ 2 ] [ 3 ]
Clues to the existence of a post-mortem transcriptome existed at least since the beginning of the 21st century, [ 4 ] but the word thanatotranscriptome (from ( thanatos-, Greek for "death") seems to have been first used in the scientific literature by Javan et al. in 2015, [ 2 ] following the introduction of the concept of the human thanatomicrobiome in 2014 at the 66th Annual Meeting of the American Academy of Forensic Sciences in Seattle, Washington. [ 5 ]
In 2016, researchers at the University of Washington confirmed that up to 2 days (48 hours) after the death of mice and zebrafish, many genes still functioned. [ 1 ] [ 3 ] Changes in the quantities of mRNA in the bodies of the dead animals proved that hundreds of genes with very different functions awoke just after death. The researchers detected 548 genes that awoke after death in zebrafish and 515 in laboratory mice . Among these were genes involved in development of the organism, including genes that are normally activated only in utero or in ovo (in the egg) during fetal development.
The thanatomicrobiome is characterized by a diverse assortment of microorganisms located in internal organs (brain, heart, liver, and spleen) and blood samples collected after a human dies. It is defined as the microbial community of internal body sites, created by a successional process whereby trillions of microorganisms populate, proliferate, and/or die within the dead body, resulting in temporal modifications in the community composition over time.
Characterization and quantification of the transcriptome in a given "dead" tissue can identify genetic assets, which can be used to determine the regulatory mechanisms and set networks of gene expression .
The techniques commonly used for simultaneously measuring the concentration of a large number of different types of mRNA include microarrays and high-throughput sequencing via RNA-Seq .
Analysis from a serology postmortem can characterize the transcriptome of a particular tissue cell type, or compare the transcriptomes between various experimental conditions. Such analysis can be complementary to the analysis of thanatomicrobiome to better understand the process of transformation of the necromass in the hours and days following death. [ 6 ]
Future applications of this information could include: | https://en.wikipedia.org/wiki/Thanatotranscriptome |
The Adventures of Massang is a Kalmyk folktale about a strong hero born of a cow, who finds three companions and has further adventures. The tale was published in the Siddi-Kur (or Siddhi-Kur ), a compilation of Kalmyk and Mongolian stories.
The story is related, in the international Aarne-Thompson-Uther Index , to type ATU 301, "The Three Stolen Princesses", as a former subtype, AaTh 301B, "The Strong Man and his Companions": a hero of hybrid human-animal origin finds strong companions and climbs down to an underworld, and is eventually betrayed by his companions.
The Tales of the Bewitched Corpse is a compilation of Indo-Tibetan stories that was later brought to Mongolia and translated to Mongolic languages . [ 1 ] [ 2 ] [ 3 ] The collection is known in India as Vetala Pañcaviṃśati , in Tibet as Ro-sgrung , in Mongolia as Siditü kegür , and in Oirat as Siddhi kǖr . [ 4 ] [ 5 ]
In this regard, Mongolian linguist Tsendiin Damdinsüren noted the existence of two Tibetan compilations of Vetala tales, one with 13 chapters and the other with 21. Also, both versions were mentioned in the work The Book of the Son , written in the 11th century. Lastly, the divergence in contents between the Indian Vetala and the Tibetan versions, according to Damdinsuren, may indicate the latter were original works, instead of an adaptation or translation. [ 6 ] In the same vein, according to Tibetologist Françoise Robin , there are more than 20 versions of the compilation in the Tibetan-speaking zone alone, and their common versions contain between thirteen and twenty-five stories, with some even reaching up to 75 tales. [ 7 ]
Hungarian Mongolist Lászlo L. Lörincz (1965) noted that the tale of Massang contained two "independent" parts connected as a loose whole. [ 8 ] In the same vein, Tibetologist Rolf Stein argued the tale of Masang existed as "an indigenous tale" before being inserted into the compilation as the third story of the Tibetan and Mongolian redactions of The Bewitched Corpse , [ 9 ] being also mentioned in other works, such as Father's Teaching and the Son's Teaching (Pha-chhos, Bu-chhos), from the 11th century. [ 10 ]
In the tale How the Schimnu-Khan was Slain , of Tibetan or Mongolian provenance, the first part shows the birth of a youth named Massang "of the bull's head". A poor man's only cow gives birth to a half-man, half-cow hybrid and its owner is horrified by the creature. The cow-man, receiving clemency, flees from the old man and into the world. The youth meets a "black-coloured man (...) born of the dark woods", a "green-coloured man (...) born of the green meadows" and a "white-coloured man (...) born of the crystal rock" and the quartet soon move to a dwelling overlooking a hill. They take turns cooking the food while the others gather game nearby. One day, a small old woman appears and beats the three companions to steal their food ("milk and meat", as the story says). On the fourth day, Massang sees the little old woman and matches strength with the creature. After three tests, the little woman escapes and leaves behind a blood trail for the four heroes to follow. They soon come to an opening in the rock; down below, the witch's corpse strewn about near heaps and heaps of treasure. Massang descends to take the treasure to his companions but they betray him and leave him for dead in the pit. Massang sleeps on the witch's corpse - for years - and when he awakes, three cherry trees have sprouted, which he uses to climb to the surface. He visits his treacherous companions and discovers they have made a life for themselves with the witch's treasure, but they beg Massang to spare them. [ 11 ]
In the second part of the tale, Massang decides to spare his former companions and carries on with his life. He finds a beautiful maiden carrying water in a jug and follows her. Massang arrives at the court of Churmusta Tengri , who bids welcome to the hero and tells him his arrival is most propitious. Churmusta Tengri explains that there will be a war between a white host of Tengri forces and the black host of the Schummu. Massang helps the white hosts by defeating the black host leader. At the end of the tale, a Schummu strikes a hammer against the ground and sparks fly out, originating seven stars of a constellation ( Ursa Major or the Pleiades ). [ 12 ] In this version of the tale, translated by British folklorist Rachel Harriette Busk , the narrator, in the framing device of the book, comments that he never returned to his master to bring him riches.
Charles Fillingham Coxwell [ de ] translated the tale as Massang's Adventure . In his translation, Massang's companions are a "dark complexioned man (...) descended from the forest", a man of green colour "born of the turf" and a white man originated from crystal. [ 13 ]
The tale was also translated by Charles John Tibbits as The Adventures of Massang , wherein Massang is described as horned; the dark man is called Iddar, Son of the Forest, and the other two Son of the Grass and Son of the Sedges. In his translation, the Schummu smites Massang and from this action seven stars spring out. [ 14 ]
In a Russian language translation of the tale, titled "Массанг" ("Massang"), published in 1978, the hero's companions are given the following names: Idder (Иддер) of the dark woods; Geger (Гегер) of the green fields/meadows; and Adder (Аддер) of the white mountains. This tale also contains the origins of the constellation, but ends on a happy note. [ 15 ]
Massang also appears in a Tibetan and in a Kalmyk tale. In the latter, he is born from a human couple in the country of India , but still shows the bull/ox features, like horns and a tail. [ 16 ]
In a version of the tale translated by author Eleanore Myers Jewett with the title The Promise of Massang , sourced as Tibetan, the translator removed the animal birth of the hero, thus making him a normal boy instead. The tale lacks the second part about the origin of the constellation, and ends with Massang bringing the cow's owner the riches he promised. [ 17 ]
According to German Tibetologist Dieter Schuh , the tale of the ox-man and the origin of the constellation appears in both Tibetan and Mongolian literature. [ 18 ] Hungarian orientalist László L. Lőrincz remarked that the tale is attested in a Tibetan collection named Ro-sgruṅ ("The Magic Corpse"), with the title Ya-ru-kha-khra'i le'u-ste . He also noted that the tale is popular in Mongolia, published in the Siditü kegür , and the hero may be known by the Tibetan name Yarupa or by Masang . [ 19 ]
Hungarian orientalist László L. Lőrincz established the classification of the Mongolian tale corpus, published as Mongolische Märchentypus ("MMT"). In his system, he indexed a Mongolian type numbered MMT 127, Der kalbsköpfige Masang ("The Calf-Headed Masang"), which corresponds to tale type 301B. In the tale type, a hybrid son is born of a union between a man and a cow or a man and a she-bear; in his youth he meets equally powerful companions and they move out to a house; a diminute demoness attacks the heroes while they are preparing food, and Masang defeats her; they follow the trail to a hole and Masang descends and defeats the witch; he steals the demoness's treasure, but his companions abandon him down below; to escape, he plants a magical seed for a tree to grow or a bird carries him up to the surface. Later, Masang helps deity Qormusda in his battle against demons; Qormusda either transforms Masang to human form, or he dies and his body is sundered to make the Ursa Major constellation; or he intervenes in a war between two Khans and marries the daughter of the victor. [ 20 ]
György Kara , Hungarian professor of Mongolian studies , provided a Hungarian language translation of a Mongolian tale with the title "Ам цагаан бяруу". In his translation, titled Am Cagán Bjarú, a Fehérszájú Borjú ("Am Cagán Bjarú, The White-Mouthed Calf"), the constellation Dolon Burhan ("The Seven Buddhas") was originally a man named White-Mouthed Calf. The story is largely the same: the ox-man hero is born of a cow, meets three companions (a man from the forest, a man from the woods, and a man sat on a stone), and finds them a house. While there, a mysterious old woman appears and demands a bit of their food, and attacks them after being denied. The White-Mouthed Calf hurts the old woman and follows her to a pit, he is betrayed by his companions, but reaches the surface after three years by climbing on three trees that sprouted on the old woman's corpse. At the end of the tale, the White-Mouthed Calf helps the Celestial Emperor against the Emperor of Demons, but an evil woman, ally of the Emperor of Demons, strikes the hero with a weapon and his body is torn apart in seven pieces. The Celestial Emperor takes the seven pieces and creates the Seven Buddhas constellation. [ 21 ]
Folklorist Elizaveta V. Barannikova [ uk ] translated and published a Buryat tale titled "Тугал Масан" ("Tugal Masan"). The tale is inserted as a story-within-a-story told by the Burkhan: Tugal Masan meets a Black Tarba, a White Tarba, and a Blue Tarba. In the part about the celestial king, Tugal Masan is recruited to fight against the black yak army of Khara Lusan Khan. At the end of the tale, Tugal Masan survives and is offered to marry the daughter of the celestial king, but he declines. [ 22 ]
Tibetologist David MacDonald translated and published a Tibetan tale he titled The Story of Yakro Kharto . In this tale, a widowed man goes hunting and finds the bull-man in the forest. The bull-man, named Yakro Kharto, begs to be spared and flees into the woods. He meets three companions: a black man named Forest-Born, a green youth named Born-in-the-Grass and another named Born-in-a-Glass-House. The tale is much the same: the companions' betrayal, the small old woman and the return to the surface by climbing the peach tree. In the second part of the story, Yakro Kharto follows the maiden and meets King Gyajin, who asks his help in defeat in the evil spirits. At the end of the tale, the gods descend a rope from the heavens which Yakro Kharto climbs up and reaches the stars. [ 23 ]
In a variant titled Masang Yharu Khadra , sourced as from Tibet , the hero is born with a bull's head and tail and given the name Masang Yharu Khadra. He meets his companions (a man with face as black as wood bark, another with face as blue as the grasslands, and the third with face as pale as a rock). He is betrayed in the same manner and escapes the hole by climbing up three peach trees. When he meets the girl, he follows her and climbs up a rose vine to the sky, where he meets the leader of the gods of heaven, who enlists Masang's help. The next day, the forces of heaven assume the shape of white yaks and fight the demonic forces, who are in the shape of black yaks. [ 24 ]
In a Russian language translation by Tibetologist Yuri Parfionovich [ ru ] , the hero's name is given as "Пегий бычок" (English: " Piebald Bull Calf"), and its source is explicitly named "Игра Веталы с человеком" (" Vetala 's Game with a Man"). [ 25 ]
Folklorist William Ralston Shedden-Ralston called Massang the " Calmuck Minotaur ", in reference to the hybrid bull-man creature of Greek myth. [ 26 ] Charles Fillingham Coxwell also related Massang to the Greek Minotaur. [ 27 ]
Coxwell saw a parallel between Massang and Lorraine (French) hero "John of the Bear" ( Jean de l'Ours ), another strong hero with animal parentage. [ 28 ] [ 29 ]
Hungarian scholarship argue for a parallel between the Kalmyk Massang and a similar figure of Hungarian folktales: Fehérlófia ('Son of the White Mare'), a youth born of a white mare. [ 30 ] [ 31 ]
W. R. S. Ralston related the story to an international narrative wherein a hero, joined by two companions (his brothers or not), follows a creature to its underground lair; the hero is lowered by a rope and finds down there either kidnapped princesses or some treasure. Either way, the hero is abandoned by the other two in the underground to perish, but eventually escapes and punishes his traitorous companions. [ 32 ] These tales were later classified in the international index Aarne-Thompson-Uther as tale type ATU 301, The Three Stolen Princesses (or The Three Underground Kingdoms , in Russian academia). [ 33 ] [ 34 ] [ 35 ]
According to philologist researcher Irina S. Nadbitova, from the Kalmyk Institute for Humanities research RAS, a similar narrative exists in the Kalmyk Folktale Corpus, but the bull-man hero is disenchanted by a girl at the end of the tale. Nadbitova classified it as type 430, "Юноша-бык" ("The Bull Youth"). [ 36 ]
The little old woman who attacks the heroes is described as a Schimnu or Schumnu , which the translator considered to be a version of Mara , a demonic being in Buddhism . [ 37 ]
Lörincz suggests that the coloured companions in the Tibetan tale may represent guardian spirits of the woods, the meadows and the mountains, or be interpreted as indications of the cardinal directions . [ 38 ] Also, the heavenly deity or king, named Dbaṅ-po brgya-byin in the Tibetan text, is equivalent to Sanskrit Śatakratu , that is, Indra . [ 39 ]
The second part of the tale of "ox-man" Massang (or Masn Mirü) involves his fight against a powerful enemy king and the origin of a constellation. However, scholarship suggests that this second part is an addition to the original tale. [ 40 ] Scholarship points out that the story of Massang serves as an etiological tale to the origin of a seven-star constellation known as "Долон Эбуген" ("Seven Elders") or "Долан Бурхн" ("Seven Deities"). [ 41 ] According to Hungarian orientalist László L. Lőrincz , the tale is another myth to explain the origin of the Great Bear . [ 42 ] | https://en.wikipedia.org/wiki/The_Adventures_of_Massang |
The Alignment Problem: Machine Learning and Human Values is a 2020 non-fiction book by the American writer Brian Christian . It is based on numerous interviews with experts trying to build artificial intelligence systems, particularly machine learning systems, that are aligned with human values.
The book is divided into three sections: Prophecy, Agency, and Normativity. Each section covers researchers and engineers working on different challenges in the alignment of artificial intelligence with human values.
In the first section, Christian interweaves discussions of the history of artificial intelligence research, particularly the machine learning approach of artificial neural networks such as the Perceptron and AlexNet , with examples of how AI systems can have unintended behavior. He tells the story of Julia Angwin , a journalist whose ProPublica investigation of the COMPAS algorithm, a tool for predicting recidivism among criminal defendants, led to widespread criticism of its accuracy and bias towards certain demographics. One of AI's main alignment challenges is its black box nature (inputs and outputs are identifiable but the transformation process in between is undetermined). The lack of transparency makes it difficult to know where the system is going right and where it is going wrong.
In the second section, Christian similarly interweaves the history of the psychological study of reward, such as behaviorism and dopamine , with the computer science of reinforcement learning , in which AI systems need to develop policy ("what to do") in the face of a value function ("what rewards or punishment to expect"). He calls the DeepMind AlphaGo and AlphaZero systems "perhaps the single most impressive achievement in automated curriculum design." He also highlights the importance of curiosity, in which reinforcement learners are intrinsically motivated to explore their environment, rather than exclusively seeking the external reward.
The third section covers training AI through the imitation of human or machine behavior, as well as philosophical debates such as between possibilism and actualism that imply different ideal behavior for AI systems. Of particular importance is inverse reinforcement learning , a broad approach for machines to learn the objective function of a human or another agent. Christian discusses the normative challenges associated with effective altruism and existential risk , including the work of philosophers Toby Ord and William MacAskill who are trying to devise human and machine strategies for navigating the alignment problem as effectively as possible.
The book received positive reviews from critics. The Wall Street Journal 's David A. Shaywitz emphasized the frequent problems when applying algorithms to real-world problems, describing the book as "a nuanced and captivating exploration of this white-hot topic." [ 2 ] Publishers Weekly praised the book for its writing and extensive research. [ 3 ]
Kirkus Reviews gave the book a positive review, calling it "technically rich but accessible", and "an intriguing exploration of AI." [ 4 ] Writing for Nature , Virginia Dignum gave the book a positive review, favorably comparing it to Kate Crawford 's Atlas of AI . [ 5 ]
In 2021, journalist Ezra Klein had Christian on his podcast, The Ezra Klein Show, writing in The New York Times , " The Alignment Problem is the best book on the key technical and moral questions of A.I. that I’ve read." [ 6 ] Later that year, the book was listed in a Fast Company feature, "5 books that inspired Microsoft CEO Satya Nadella this year". [ 7 ]
In 2022, the book won the Eric and Wendy Schmidt Award for Excellence in Science Communication , given by The National Academies of Sciences, Engineering, and Medicine in partnership with Schmidt Futures . [ 8 ]
In 2024, The New York Times named The Alignment Problem one of the "5 Best Books About Artificial Intelligence," saying: "If you're going to read one book on artificial intelligence, this is the one." [ 9 ] | https://en.wikipedia.org/wiki/The_Alignment_Problem |
The Ambidextrous Universe is a popular science book by Martin Gardner , covering aspects of symmetry and asymmetry in human culture, science and the wider universe . It culminates in a discussion of whether nature's conservation of parity (the symmetry of mirrored quantum systems ) is ever violated, which had been proven experimentally in 1956 .
The book was originally published in 1964 with the subtitle Left, Right, and the Fall of Parity , with a revised version following in 1969. A second edition was released in 1979 with the new subtitle Mirror Asymmetry and Time-Reversed Worlds . The third edition was released in 1990 under the title The New Ambidextrous Universe: Symmetry and Asymmetry from Mirror Reflections to Superstrings ; this was re-released with minor revisions in 2005.
The book begins with the subject of mirror reflection , and from there passes through symmetry in geometry , poetry , art , music , galaxies , stars , planets and living organisms . It then moves down into the molecular scale and looks at how symmetry and asymmetry have evolved from the beginning of life on Earth . There is a chapter on carbon and its versatility and on chirality in biochemistry .
The last several chapters deal with a conundrum called the Ozma Problem, which examines whether there is any fundamental asymmetry to the universe. This discussion concerns various aspects of atomic and subatomic physics and how they relate to mirror asymmetry and the related concepts of chirality, antimatter , magnetic and electrical polarity , parity , charge and spin . Time invariance (and reversal ) is discussed. Implications for particle physics , theoretical physics and cosmology are covered and brought up to date (in later editions of the book) with regard to Grand Unified Theories , theories of everything , superstring theory and M-theory .
The 18th chapter, "The Ozma Problem", poses a problem that Gardner claims would arise if Earth should ever enter into communication with life on another planet through Project Ozma . This is the problem of how to communicate the meaning of left and right, where the two communicants are conditionally not allowed to view any one object in common.
The problem was first implied in Immanuel Kant 's discussion of a hand isolated in space, which would have no meaning as left or right by itself; Gardner posits that Kant would today explain his problem using the reversibility of objects through a higher dimension . A three-dimensional hand can be reversed in a mirror or a hypothetical fourth dimension . In more easily visualizable terms, an outline of a hand in Flatland could be flipped over; the meaning of left or right would not apply until a being missing a corresponding hand came along. [ 1 ] Charles Howard Hinton expressed the essential problem in 1888, as did William James in his The Principles of Psychology (1890). [ 2 ] Gardner follows the thread of several false leads on the road to the solution of the problem, such as the magnetic poles of astronomical bodies and the chirality of life molecules, which could be arbitrary based on how life locally originated. [ 3 ]
The solution to the Ozma Problem was finally realized in the famous Wu experiment , conducted in 1956 by Chinese-American physicist Chien-Shiung Wu (1912–1997), involving the beta decay of cobalt-60 . At a conference earlier that year, Richard Feynman had asked (on behalf of Martin M. Block ) whether parity was sometimes violated, leading Tsung-Dao Lee and Chen-Ning Yang to propose Wu's experiment, for which Lee and Yang were awarded the 1957 Nobel Prize in Physics . It was the first experiment to disprove the conservation of parity, and according to Gardner, one could use it to convey the meaning of left and right to remote extraterrestrials. An earlier example of asymmetry had actually been detected as early as 1928 in the decay of a radionuclide of radium , but its significance was not then realized. [ 4 ]
The Ambidextrous Universe references several physics-themed poems and certain works of literature which help to illustrate various points. Additionally, some other works have referenced Gardner's book.
W. H. Auden alludes to The Ambidextrous Universe in his poem "Josef Weinheber" (1965).
In the original 1964 edition of The Ambidextrous Universe , Gardner quoted two lines of poetry from Vladimir Nabokov 's 1962 novel Pale Fire which are supposed to have been written by a poet, " John Shade ", who is actually fictional. As a joke, Gardner credited the lines only to Shade and put Shade's name in the index as if he were a real person. In his 1969 novel Ada or Ardor: A Family Chronicle , Nabokov returned the favor by having the character Van Veen "quote" the Gardner book along with the two lines of verse:
"Space is a swarming in the eyes, and Time a singing in the ears," says John Shade, a modern poet, as quoted by an invented philosopher ("Martin Gardiner" [ sic ]) in The Ambidextrous Universe , page 165 [ sic ]. [ 5 ]
Nabokov's 1974 novel Look at the Harlequins! , about a man who cannot distinguish left from right, was heavily influenced by his reading of The Ambidextrous Universe . [ 6 ] [ 7 ] | https://en.wikipedia.org/wiki/The_Ambidextrous_Universe |
The Analyst (subtitled A Discourse Addressed to an Infidel Mathematician: Wherein It Is Examined Whether the Object, Principles, and Inferences of the Modern Analysis Are More Distinctly Conceived, or More Evidently Deduced, Than Religious Mysteries and Points of Faith ) is a book by George Berkeley . It was first published in 1734, first by J. Tonson (London), then by S. Fuller (Dublin). The "infidel mathematician" is believed to have been Edmond Halley , though others have speculated Sir Isaac Newton was intended. [ 1 ]
The book contains a direct attack on the foundations of calculus , specifically on Isaac Newton's notion of fluxions and on Leibniz 's notion of infinitesimal change.
From his earliest days as a writer, Berkeley had taken up his satirical pen to attack what were then called ' free-thinkers ' ( secularists , sceptics , agnostics , atheists , etc.—in short, anyone who doubted the truths of received Christian religion or called for a diminution of religion in public life). [ 2 ] In 1732, in the latest installment in this effort, Berkeley published his Alciphron , a series of dialogues directed at different types of 'free-thinkers'. One of the archetypes Berkeley addressed was the secular scientist, who discarded Christian mysteries as unnecessary superstitions , and declared his confidence in the certainty of human reason and science. Against his arguments, Berkeley mounted a subtle defense of the validity and usefulness of these elements of the Christian faith.
Alciphron was widely read and caused a bit of a stir. But it was an offhand comment mocking Berkeley's arguments by the 'free-thinking' royal astronomer Sir Edmund Halley that prompted Berkeley to pick up his pen again and try a new tack. The result was The Analyst , conceived as a satire attacking the foundations of mathematics with the same vigour and style as 'free-thinkers' routinely attacked religious truths.
Berkeley sought to take apart the then foundations of calculus, claimed to uncover numerous gaps in proof, attacked the use of infinitesimals , the diagonal of the unit square , the very existence of numbers, etc. The general point was not so much to mock mathematics or mathematicians, but rather to show that mathematicians, like Christians, relied upon incomprehensible ' mysteries ' in the foundations of their reasoning. Moreover, the existence of these 'superstitions' was not fatal to mathematical reasoning, indeed it was an aid. So too with the Christian faithful and their 'mysteries'. Berkeley concluded that the certainty of mathematics is no greater than the certainty of religion.
The Analyst was a direct attack on the foundations of calculus , specifically on Newton's notion of fluxions and on Leibniz 's notion of infinitesimal change. In section 16, Berkeley criticises
...the fallacious way of proceeding to a certain Point on the Supposition of an Increment, and then at once shifting your Supposition to that of no Increment . . . Since if this second Supposition had been made before the common Division by o , all had vanished at once, and you must have got nothing by your Supposition. Whereas by this Artifice of first dividing, and then changing your Supposition, you retain 1 and nx n-1 . But, notwithstanding all this address to cover it, the fallacy is still the same. [ 3 ]
It is a frequently quoted passage, particularly when he wrote: [ 4 ] [ 5 ]
And what are these Fluxions? The Velocities of evanescent Increments? And what are these same evanescent Increments? They are neither finite Quantities nor Quantities infinitely small, nor yet nothing. May we not call them the ghosts of departed quantities? [ 6 ]
Berkeley did not dispute the results of calculus; he acknowledged the results were true. The thrust of his criticism was that Calculus was not more logically rigorous than religion. He instead questioned whether mathematicians "submit to Authority, take things upon Trust" [ 7 ] just as followers of religious tenets did. According to Burton, Berkeley introduced an ingenious theory of compensating errors that were meant to explain the correctness of the results of calculus. Berkeley contended that the practitioners of calculus introduced several errors which cancelled, leaving the correct answer. In his own words, "by virtue of a twofold mistake you arrive, though not at science, yet truth." [ 8 ]
The idea that Newton was the intended recipient of the discourse is put into doubt by a passage that appears toward the end of the book: "Query 58: Whether it be really an effect of Thinking, that the same Men admire the great author for his Fluxions, and deride him for his Religion?" [ 9 ]
Here Berkeley ridicules those who celebrate Newton (the inventor of "fluxions", roughly equivalent to the differentials of later versions of the differential calculus) as a genius while deriding his well-known religiosity. Since Berkeley is here explicitly calling attention to Newton's religious faith, that seems to indicate he did not mean his readers to identify the "infidel (i.e., lacking faith) mathematician" with Newton.
Mathematics historian Judith Grabiner comments, "Berkeley's criticisms of the rigor of the calculus were witty, unkind, and — with respect to the mathematical practices he was criticizing — essentially correct". [ 10 ] While his critiques of the mathematical practices were sound, his essay has been criticised on logical and philosophical grounds.
For example, David Sherry argues that Berkeley's criticism of infinitesimal calculus consists of a logical criticism and a metaphysical criticism. The logical criticism is that of a fallacia suppositionis , which means gaining points in an argument by means of one assumption and, while keeping those points, concluding the argument with a contradictory assumption. The metaphysical criticism is a challenge to the existence itself of concepts such as fluxions, moments, and infinitesimals, and is rooted in Berkeley's empiricist philosophy which tolerates no expression without a referent. [ 11 ] Andersen (2011) showed that Berkeley's doctrine of the compensation of errors contains a logical circularity. Namely, Berkeley's determination of the derivative of the quadratic function relies on Apollonius's determination of the tangent of the parabola. [ 12 ]
Two years after this publication, Thomas Bayes published anonymously "An Introduction to the Doctrine of Fluxions, and a Defence of the Mathematicians Against the Objections of the Author of the Analyst" (1736), in which he defended the logical foundation of Isaac Newton's calculus against the criticism outlined in The Analyst . Colin Maclaurin 's two-volume Treatise of Fluxions published in 1742 also began as a response to Berkeley attacks, intended to show that Newton's calculus was rigorous by reducing it to the methods of Greek geometry . [ 10 ]
Despite these attempts, calculus continued to be developed using non-rigorous methods until around 1830 when Augustin Cauchy , and later Bernhard Riemann and Karl Weierstrass , redefined the derivative and integral using a rigorous definition of the concept of limit . The idea of using limits as a foundation for calculus had been suggested by d'Alembert , but d'Alembert's definition was not rigorous by modern standards. [ 13 ] The concept of limits had already appeared in the work of Newton, [ 14 ] but was not stated with sufficient clarity to hold up to the criticism of Berkeley. [ 15 ]
In 1966, Abraham Robinson introduced Non-standard Analysis , which provided a rigorous foundation for working with infinitely small quantities. This provided another way of putting calculus on a mathematically rigorous foundation, the way it was done before the (ε, δ)-definition of limit had been fully developed.
Towards the end of The Analyst, Berkeley addresses possible justifications for the foundations of calculus that mathematicians may put forward. In response to the idea fluxions could be defined using ultimate ratios of vanishing quantities, [ 16 ] Berkeley wrote:
It must, indeed, be acknowledged, that [Newton] used Fluxions, like the Scaffold of a building, as things to be laid aside or got rid of, as soon as finite Lines were found proportional to them. But then these finite Exponents are found by the help of Fluxions. Whatever therefore is got by such Exponents and Proportions is to be ascribed to Fluxions: which must therefore be previously understood. And what are these Fluxions? The Velocities of evanescent Increments? And what are these same evanescent Increments? They are neither finite Quantities nor Quantities infinitely small, nor yet nothing. May we not call them the Ghosts of departed Quantities? [ 6 ]
Edwards describes this as the most memorable point of the book. [ 15 ] Katz and Sherry argue that the expression was intended to address both infinitesimals and Newton's theory of fluxions. [ 17 ]
Today the phrase "ghosts of departed quantities" is also used when discussing Berkeley's attacks on other possible foundations of Calculus. In particular it is used when discussing infinitesimals , [ 18 ] but it is also used when discussing differentials , [ 19 ] and adequality . [ 20 ]
The full text of The Analyst can be read on Wikisource , as well as on David R. Wilkins' website, [ 21 ] which includes some commentary and links to responses by Berkeley's contemporaries.
The Analyst is also reproduced, with commentary, in recent works:
Ewald concludes that Berkeley's objections to the calculus of his day were mostly well taken at the time. | https://en.wikipedia.org/wiki/The_Analyst |
The Angiogenesis Foundation , is a United States 501(c)(3) nonprofit organization established in 1994 for the study of angiogenesis . The foundation developed a therapy for canine cancer, called the Navy Protocol. This treatment works by starving the tumor of its blood supply. [ 1 ] In 2004, they helped publicly launch the first antiangiogenic therapy for cancer, bevacizumab , starting with colorectal cancer. [ 2 ] In 2010, the president and co-founder of the Angiogenesis Foundation, William Li, gave a well-received presentation at the TED conference on cancer prevention through antiangiogenic nutrition. [ 3 ]
Co-founder Dr. William Li won the 2024 Dr. Andrew von Eschenbach Award for his work in angiogenesis. [ 4 ]
This article about a medical organization or association is a stub . You can help Wikipedia by expanding it . | https://en.wikipedia.org/wiki/The_Angiogenesis_Foundation |
" The Apportionment of Human Diversity " is a 1972 paper on racial categorisation by American evolutionary biologist Richard Lewontin . [ 1 ] In it, Lewontin presented an analysis of genetic diversity amongst people from different conventionally-defined races. His main finding, that there is more genetic variation within these populations than between them, [ 2 ] is considered a landmark in the study of human genetic variation and contributed to the abandonment of race as a scientific concept. [ 3 ] [ 4 ] [ 5 ]
By the 1960s, anthropologists such as Frank B. Livingstone had concluded that "there are no races, there are only clines" – smooth gradients of genetic variation in a species across its geographic range . Lewontin's mentor Theodosius Dobzhansky challenged this, arguing that there are human discrete populations that can be distinguished by differences in the frequency of genetic traits, which he called races. [ 6 ] At that time the debate was largely semantic, stemming from their different ideas about what race is and how it would be manifested in humans genetics. [ 6 ] [ 7 ] The evidence that was available to Livingstone and Dobzhansky was mostly limited to qualitative observations of phenotypes thought to express genetic variation (e.g. skin colour ). [ 6 ] This changed over the course of the 1960s, as new techniques began to produce direct evidence for genetic variation in humans at a molecular level . [ 8 ] By 1972, when Dobzhansky invited Lewontin to contribute to his edited volume of Evolutionary Biology , Lewontin felt that there was sufficient data to look at the problem anew, from a "firm quantitative basis": [ 8 ]
And so I thought, 'Well, we've got enough of this data, let's see what it tells us about the differences between human groups'. And so I just looked into the literature, and that literature was in books and so on. [...] One day I was going to give a lecture, I think it was in Carbondale, Illinois, or somewhere south. I was working in Chicago at the time. So I took a couple of these books with me and a pad of paper, and a table of logarithms which I needed for this purpose, and a little hand calculator, and I sat on this bus trip for three or four hours looking at the books, picking out the data, looking it up in the table of logarithms, doing a calculation, and writing it down in tables. And when I got back after the round trip I had all the data I needed to write the paper about how much human genetic variation there was, and so I did it.
Lewontin had been interested in using quantitative methods to assess taxonomic categories for some time before 1972. Over a decade earlier, palaeontologist George Gaylord Simpson had invited him to co-author a second edition of his textbook Quantitative Zoology (1960), and Lewontin added a chapter on the analysis of variance . In it, he illustrated how this approach could be used distinguish geographically distinct races with the example of Drosophila persimilis , a species of fruit fly. Though the method was similar to that he would later apply to human genetic variation, he reached the opposite conclusion: there was much greater genetic variance between geographic populations than between individual fruit flies, so there was a reasonable basis for distinguishing taxonomic races. [ 8 ] Foreshadowing his later work on human genetic variation, he also emphasised that, because there will always be measurable differences between any two populations, it is the degree of difference compared to other axes of variation that will determine whether a grouping is biologically significant. [ 8 ] "The Apportionment of Human Diversity" was published in a volume dedicated to Simpson, perhaps prompting Lewontin to recall this previous work. [ 8 ]
Lewontin performed a statistical analysis of the fixation index ( F ST ) in populations drawn from seven classically-defined "races" (Caucasian, African, Mongoloid, South Asian Aborigines, Amerinds, Oceanians, and Australian Aborigines). At that time, direct sequence data from the human genome was not sufficiently available, so he instead used 17 indirect markers, including blood group proteins. Lewontin found that the majority of the total genetic variation between humans (i.e., of the 0.1% of DNA that varies between individuals), 85.4%, is found within populations, 8.3% of the variation is found between populations within a "race", and only 6.3% was found to account for the racial classification. Numerous later studies have confirmed his findings. [ 9 ] Based on this analysis, Lewontin concluded, "Since such racial classification is now seen to be of virtually no genetic or taxonomic significance either, no justification can be offered for its continuance." [ page needed ]
In a 2003 paper, Cambridge geneticist A. W. F. Edwards criticized Lewontin's conclusion that race is an invalid taxonomic construct, terming it Lewontin's fallacy . He showed that the probability of racial misclassification of an individual based on variation in a single genetic locus is approximately 30%, but the misclassification probability approaches zero when enough loci are studied. [ 10 ] Edwards' paper was commented on by Jonathan Marks , who argued that "the point of the theory of race was to discover large clusters of people that are principally homogeneous within and heterogeneous between, contrasting groups. Lewontin's analysis shows that such groups do not exist in the human species, and Edwards' critique does not contradict that interpretation." [ 11 ]
Many subsequent studies confirmed Lewontin's main finding. [ 12 ] [ 13 ] [ 14 ]
The paper was not frequently cited in the years following its publication. [ 2 ] [ 15 ]
Fifty years after its publication, the paper was found to be frequently referenced in social media . [ 15 ] In particular, Twitter users associated with far-right politics commonly used the term "Lewontin's fallacy" (referencing A. W. F. Edwards ' 2003 critique of Lewontin) as a rhetorical device to dismiss scientific arguments against biological race. [ 15 ] Commenting on the enduring significance afforded to Lewontin's paper in far-right and white nationalist discourse, geneticists Jedidiah Carlson and Kelley Harris proposed that "rejection of Lewontin's interpretation has become a tenet of white nationalist ideology". [ 15 ]
In 2022, a special issue of the journal Philosophical Transactions of the Royal Society B: Biological Sciences was published with the theme "Celebrating 50 years since Lewontin's apportionment of human diversity", [ 16 ] and a section of the book Remapping Race in a Global Context was devoted to discussing Lewontin's paper and defending it against Edwards' critique. [ 17 ] | https://en.wikipedia.org/wiki/The_Apportionment_of_Human_Diversity |
The Assayer ( Italian : Il saggiatore ) is a book by Galileo Galilei , published in Rome in October 1623. It is generally considered to be one of the pioneering works of the scientific method , first broaching the idea that the book of nature is to be read with mathematical tools rather than those of scholastic philosophy , as generally held at the time. Despite the retroactive acclaim given to Galileo's theory of knowledge, the empirical claims he made in the book—that comets are sublunary and their observed properties the product of optical phenomena—were incorrect. [ 1 ]
In 1619, Galileo became embroiled in a controversy with Father Orazio Grassi , professor of mathematics at the Jesuit Collegio Romano . It began as a dispute over the nature of comets, but by the time Galileo had published The Assayer , his last salvo in the dispute, it had become a much wider controversy over the very nature of science itself.
The debate between Galileo and Grassi started in early 1619, when Father Grassi anonymously published the pamphlet, An Astronomical Disputation on the Three Comets of the Year 1618 ( Disputatio astronomica de tribus cometis anni MDCXVIII ), [ 2 ] which discussed the nature of a comet that had appeared late in November of the previous year . Grassi concluded that the comet was a fiery, celestial body that had moved along a segment of a great circle at a constant distance from the earth, [ 3 ] [ 4 ] and since it moved in the sky more slowly than the Moon, it must be farther away than the Moon.
Grassi adopted Tycho Brahe 's Tychonic system , in which the other planets of the Solar System orbit around the Sun , which, in turn, orbits around the Earth . In his Disputatio Grassi referenced many of Galileo's observations, such as the surface of the Moon and the phases of Venus , without mentioning him. Grassi argued from the apparent absence of observable parallax that comets move beyond the Moon. Galileo never explicitly stated that comets are an illusion, but merely wondered if they are real or an optical illusion.
Grassi's arguments and conclusions were criticised in a subsequent pamphlet, Discourse on Comets , [ 5 ] published under the name of one of Galileo's disciples, a Florentine lawyer named Mario Guiducci , although it had been largely written by Galileo himself. [ 6 ] Galileo and Guiducci offered no definitive theory of their own on the nature of comets, [ 7 ] [ 8 ] although they did present some tentative conjectures that are now known to be mistaken. (The correct approach to the study of comets had been proposed at the time by Tycho Brahe.) In its opening passage, Galileo and Guiducci's Discourse gratuitously insulted the Jesuit Christoph Scheiner , [ 9 ] [ 10 ] [ 11 ] and various uncomplimentary remarks about the professors of the Collegio Romano were scattered throughout the work. [ 9 ]
The Jesuits were offended, [ 8 ] [ 9 ] and Grassi soon replied with a polemical tract of his own, The Astronomical and Philosophical Balance ( Libra astronomica ac philosophica ), [ 12 ] under the pseudonym Lothario Sarsio Sigensano, purporting to be one of his own pupils.
The Assayer was Galileo's devastating reply to the Astronomical Balance . [ 13 ] It has been widely recognized as a masterpiece of polemical literature, [ 14 ] [ 15 ] in which "Sarsi's" arguments are subjected to withering scorn. [ 16 ] It was greeted with wide acclaim, and particularly pleased the new pope, Urban VIII , to whom it had been dedicated. [ 17 ] In Rome, in the previous decade, Barberini, the future Urban VIII, had come down on the side of Galileo and the Lincean Academy . [ 18 ]
Galileo's dispute with Grassi permanently alienated many Jesuits, [ 19 ] and Galileo and his friends were convinced that they were responsible for bringing about his later condemnation, [ 20 ] although supporting evidence for this is not conclusive. [ 21 ] [ 22 ]
In 1616 Galileo may have been silenced on Copernicanism . In 1623 his supporter and friend, Cardinal Maffeo Barberini , a former patron of the Accademia dei Lincei and uncle of future Cardinal Francesco Barberini , became Pope Urban VIII . The election of Barberini seemed to assure Galileo of support at the highest level in the Church. A visit to Rome confirmed this. The Assayer is a milestone in the history of science: here Galileo describes the scientific method , which was quite a revolution at the time.
The title page of The Assayer shows the crest of the Barberini family , featuring three busy bees. In The Assayer , Galileo weighs the astronomical views of a Jesuit, Orazio Grassi, and finds them wanting. The book was dedicated to the new pope. The title page also shows that Urban VIII employed a member of the Lynx, Cesarini, at a high level in the papal service. This book was edited and published by members of the Lynx.
In The Assayer Galileo mainly criticized Grassi's method of inquiry, heavily biased by his religious belief and based on ipse dixit , rather than his hypothesis on comets. Furthermore, he insisted that natural philosophy (i.e. physics ) should be mathematical. According to the title page, he was the philosopher (i.e. physicist) of the Grand Duke of Tuscany , not merely the mathematician. Natural philosophy (physics) spans the gamut from processes of generation and growth (represented by a plant) to the physical structure of the universe, represented by the cosmic cross-section. Mathematics, on the other hand, is symbolized by telescopes, and an astrolabe .
The Assayer contains Galileo's famous statement that mathematics is the language of science. Only through mathematics can one achieve lasting truth in physics. Those who neglect mathematics wander endlessly in a dark labyrinth. From the book: [ 23 ]
Philosophy [i.e. natural philosophy] is written in this grand book—I mean the Universe—which stands continually open to our gaze, but it cannot be understood unless one first learns to comprehend the language and interpret the characters in which it is written. It is written in the language of mathematics, and its characters are triangles, circles, and other geometrical figures, without which it is humanly impossible to understand a single word of it; without these, one is wandering around in a dark labyrinth.
Galileo used a sarcastic and witty tone throughout the essay. The book was read with delight at the dinner table by Urban VIII. [ 18 ] In 1620 Maffeo Barberini wrote a poem entitled Adulatio Perniciosa in Galileo's honor. [ 24 ] An official, Giovanni di Guevara, said that The Assayer was free from any unorthodoxy. [ 25 ]
In The Assayer Galileo described heat as an artifact of our minds. He wrote that heat, pressure, smell and other phenomena perceived by our senses are apparent properties only, caused by the movement of particles, which is a real phenomenon. [ 26 ] [ 27 ] Galileo also theorized that senses such as smell and taste are made possible by the release of tiny particles from their host substances, which was correct but not proven until later. [ 28 ]
... about the proposition “motion is the cause of heat”... I suspect that people in general have a concept of this which is very remote from the truth. For they believe that heat is a real phenomenon, or property ... which actually resides in the material by which we feel ourselves warmed. [ 26 ]
Whenever I conceive any ... corporeal substance, I immediately ... think of it as ... having this or that shape; as being large or small ... and in some specific place at any given time; as being in motion or at rest; as touching or not touching some other body; and as being one in number, or few, or many. From these conditions I cannot separate such a substance by any stretch of my imagination. But that it must be white or red, bitter or sweet, noisy or silent, and of sweet or foul odor, my mind does not feel compelled ... Without the senses ... reason ... would probably never arrive at qualities like these. Hence I think that tastes, odors, colors, and so on are no more than mere names so far as the object in which we place them is concerned, and that they reside only in the consciousness. Hence if the living creature were removed, all these qualities would be ... annihilated. [ 29 ]
Those minute particles ... may enter by our nostrils and strike upon some small protuberances which are the instrument of smelling; here likewise their touch ... is received to our like or dislike according as they have this or that shape, are fast or slow, and are numerous or few. [ 30 ] | https://en.wikipedia.org/wiki/The_Assayer |
The Astronomer's Telegram ( ATel ) is an internet-based short-notice publication service for quickly disseminating information on new astronomical observations. [ 1 ] [ 2 ] Examples include gamma-ray bursts , [ 3 ] [ 4 ] gravitational microlensing , supernovae , novae , or X-ray transients, but there are no restrictions on content matter. Telegrams are available instantly on the service's website, and distributed to subscribers via email digest within 24 hours. [ citation needed ]
The Astronomer's Telegram was launched on 17 December 1997 by Robert E. Rutledge [ 5 ] [ 6 ] with the goal of rapidly (<1 s) sharing information of interest to astronomers. Telegrams are sent out daily by email, but especially time sensitive events can be transmitted instantly. [ 7 ] Since 2013, information is also broadcast over Twitter and Facebook. [ citation needed ]
To publish, astronomers request credentials. Credentials are issued to professional astronomers and graduate students, after verification by personal contact. [ 6 ] Once credentials have been supplied and telegrams authorized, astronomers can publish telegrams directly, with no further editing. [ 8 ]
As of August 2019, over 13000 telegrams have been published.
While working at Max Planck Institute for Extraterrestrische Physik in Garching , Bob Rutledge began the site after his experience in using the web in 1995-6 as an aid in the discovery and characterization (by multiple scientists working informally and collaboratively) of the Bursting Pulsar , GRO J1744-28. Operations began in earnest at the department of astronomy of UC Berkeley where Rutledge was a visiting post-doctoral scholar with Prof. Lars Bildsten .
The service received international attention following a March 20, 2018 when Peter Dunsby submitted a report of a "very bright optical transient near the Trifid and Lagoon Nebulae". [ 9 ] Forty minutes later he posted again apologizing, saying that the object in question was "identified as Mars". [ 10 ] The Astronomer's Telegram editors presented Dunsby with a tongue-in-cheek award as discoverer of Mars. [ 11 ]
Dunsby later described the incident to Newsweek as "an honest mistake arising from simply not checking what else was in my camera frame, during an automated astrophotography session and of very little consequence in the scheme of things. The world needs to smile more, so that’s something good that has come out of this episode.” [ 12 ]
The Astronomer's Telegram currently has an editor in chief, an editor and a co-editor. [ when? ] The ATel service is free, both for publishers and readers of the telegrams. The Astronomer's Telegram ' s editors remind users to report discoveries of supernovae or comets to the Central Bureau for Astronomical Telegrams as well. [ citation needed ] | https://en.wikipedia.org/wiki/The_Astronomer's_Telegram |
The Banach–Tarski Paradox is a book in mathematics on the Banach–Tarski paradox , the fact that a unit ball can be partitioned into a finite number of subsets and reassembled to form two unit balls. It was written by Stan Wagon and published in 1985 by the Cambridge University Press as volume 24 of their Encyclopedia of Mathematics and its Applications book series. [ 1 ] [ 2 ] [ 3 ] [ 4 ] [ 5 ] A second printing in 1986 added two pages as an addendum, and a 1993 paperback printing added a new preface. [ 6 ] In 2016 the Cambridge University Press published a second edition, adding Grzegorz Tomkowicz as a co-author, as volume 163 of the same series. [ 7 ] [ 8 ] The Basic Library List Committee of the Mathematical Association of America has recommended its inclusion in undergraduate mathematics libraries. [ 8 ]
The Banach–Tarski paradox, proved by Stefan Banach and Alfred Tarski in 1924, states that it is possible to partition a three-dimensional unit ball into finitely many pieces and reassemble them into two unit balls, a single ball of larger or smaller area, or any other bounded set with a non-empty interior . Although it is a mathematical theorem, it is called a paradox because it is so counter-intuitive; in the preface to the book, Jan Mycielski calls it the most surprising result in mathematics. It is closely related to measure theory and the non-existence of a measure on all subsets of three-dimensional space, invariant under all congruences of space, and to the theory of paradoxical sets in free groups and the representation of these groups by three-dimensional rotations , used in the proof of the paradox. The topic of the book is the Banach–Tarski paradox, its proof, and the many related results that have since become known. [ 3 ] [ 5 ]
The book is divided into two parts, the first on the existence of paradoxical decompositions and the second on conditions that prevent their existence. [ 1 ] [ 7 ] After two chapters of background material, the first part proves the Banach–Tarski paradox itself, considers higher-dimensional spaces and non-Euclidean geometry , studies the number of pieces necessary for a paradoxical decomposition, and finds analogous results to the Banach–Tarski paradox for one- and two-dimensional sets. The second part includes a related theorem of Tarski that congruence-invariant finitely-additive measures prevent the existence of paradoxical decompositions, a theorem that Lebesgue measure is the only such measure on the Lebesgue measurable sets, material on amenable groups , connections to the axiom of choice and the Hahn–Banach theorem . [ 3 ] [ 7 ] Three appendices describe Euclidean groups , Jordan measure , and a collection of open problems. [ 1 ]
The second edition adds material on several recent results in this area, in many cases inspired by the first edition of the book. Trevor Wilson proved the existence of a continuous motion from the one-ball assembly to the two-ball assembly, keeping the sets of the partition disjoint at all times; this question had been posed by de Groot in the first edition of the book. [ 7 ] [ 9 ] Miklós Laczkovich solved Tarski's circle-squaring problem , asking for a dissection of a disk to a square of the same area, in 1990. [ 7 ] [ 8 ] [ 10 ] And Edward Marczewski had asked in 1930 whether the Banach–Tarski paradox could be achieved using only Baire sets ; a positive answer was found in 1994 by Randall Dougherty and Matthew Foreman . [ 8 ] [ 11 ]
The book is written at a level accessible to mathematics graduate students, but provides a survey of research in this area that should also be useful to more advanced researchers. [ 3 ] The beginning parts of the book, including its proof of the Banach–Tarski paradox, should also be readable by undergraduate mathematicians. [ 4 ]
Reviewer Włodzimierz Bzyl writes that "this beautiful book is written with care and is certainly worth reading". [ 2 ] Reviewer John J. Watkins writes that the first edition of the book "became the classic text on paradoxical mathematics" and that the second edition "exceeds any possible expectation I might have had for expanding a book I already deeply treasured". [ 8 ] | https://en.wikipedia.org/wiki/The_Banach–Tarski_Paradox_(book) |
The Billion-Dollar Molecule is a book [ 1 ] by journalist Barry Werth about the founding and early research efforts of the American biotechnology company Vertex Pharmaceuticals , which was founded in 1989 by Joshua Boger and was among the first biotechnology companies to adopt an explicit strategy of rational drug design as opposed to techniques based on combinatorial chemistry .
This book is notable as an inside look at a biotechnology company, and the stresses and marketing pressures on funding research into drug design. This book is a mixture of finance and technology.
In February, 2014, Barry Werth published a follow-on book, The Antidote , [ 2 ] that looks at Vertex 20 years later after his original effort. [ 3 ]
This article about a book on a company or brand is a stub . You can help Wikipedia by expanding it .
This article about a chemistry -related book is a stub . You can help Wikipedia by expanding it . | https://en.wikipedia.org/wiki/The_Billion-Dollar_Molecule |
The Biology of the Cell Surface is a book by American biologist Ernest Everett Just . It was published by P. Blakiston’s Son & Co in 1939. [ 1 ]
Just began writing the book in 1934 in Naples and finished it in France, shortly before being sent to a prisoner-of-war camp. He considered the book to be his "crowning achievement". The book examined the role of the cell surface in embryology, development and evolution, and presented a critique of gene theory , particularly the views of Jacques Loeb . Sapp suggests that "Just’s theorizing on the cell cortex [in this work] was unsurpassed". [ 2 ]
This article about a book on biology or natural history is a stub . You can help Wikipedia by expanding it . | https://en.wikipedia.org/wiki/The_Biology_of_the_Cell_Surface |
The COED Project , or the COmmunications and EDiting Project , was an innovative software project created by the Computer Division of NOAA , US Department of Commerce in Boulder, Colorado in the 1970s. This project was designed, purchased and implemented by the in-house computing staff rather than any official organization.
The computer division previously had a history of frequently replacing its mainframe computers . Starting with a CDC 1604 , then a CDC 3600 , a couple of CDC 3800s , and finally a CDC 6600 . The department also had an XDS 940 timesharing system which would support up to 32 users on dial-up modems. Due to rapidly changing requirements for computer resources, it was expected that new systems would be installed on a regular basis, and the resultant strain on the users to adapt to each new system was perceived to be excessive. The COED project was the result of a study group convened to solve this problem.
The project was implemented by the computer specialists who were also responsible for the purchase, installation, and maintenance of all the computers in the division. COED was designed and implemented in long hours of overtime . The data communications aspect of the system was fully implemented and resulted in greatly improved access to the XDS 940 and CDC 6600 systems. It was also used as the front end of the - Free University of Amsterdam's SARA system for many years.
A complete networked system was a pair of Modcomps : one II handled up to 256 communication ports, and one IV handled the disks and file editing. The system was designed to be fully redundant. If one pair failed the other automatically took over. All computer systems in the network were kept time-synchronized so that all file dates/times would be accurate - synchronized to the National Bureau of Standards atomic clock , housed in the same building. Another innovation was asynchronous dynamic speed recognition. After a terminal connected to a port, the user would type a Carriage Return character, and the software would detect the speed of the terminal (in the range of 110 to 9600 bit/s) and present a log in message to the user at the appropriate speed. Due to limitations of the operating systems which came with the Modcomps, new Operating systems had to be created, CORTEX for the Modcomp II's and IV BRAIN for the Modcomp IV's.
(Dates are approximate - from memory)
Those involved in the original design meetings were:
Ralph Slutz, George Sugar, Jim Winkelman and most of the COED implementors. Support was also provided by Tom Gray.
The COED implementors were:
W. Schyler (Sky) Stevenson, Project Manager and operating system implementer
Howard Bussey, Mark Emmer, David Lillie, and Vern Schryver. The 6600 interface to COED was implemented by Anthony Brittain, Dan Dechatelets and Kathy Browne. | https://en.wikipedia.org/wiki/The_COED_Project |
The Causal Angel is the third science fiction novel by Hannu Rajaniemi featuring the protagonist Jean le Flambeur . [ 1 ] It was published in July 2014 by Gollancz in the UK and by Tor in the US. The novel is the finale of a trilogy . [ 2 ] The previous novels in the series are The Quantum Thief (2010) and The Fractal Prince (2012).
After the events of The Fractal Prince , Jean le Flambeur and Mieli are separated and their sentient spacecraft Perhonen is destroyed. The two protagonists, each in their own way, struggle to decide where their loyalties lie and how to proceed in the catastrophically altered situation. Meanwhile, the Solar System is plummeting into an all-out war of unprecedented scale and consequence. The most powerful factions, the Sobornost and the Zoku, are gathering their forces and making their plays, while simultaneously being torn apart by internal strifes.
This article about a 2010s science fiction novel is a stub . You can help Wikipedia by expanding it .
See guidelines for writing about novels . Further suggestions might be found on the article's talk page . | https://en.wikipedia.org/wiki/The_Causal_Angel |
The Cheese Mites ( 1903 ) is a British short silent documentary film , produced by Charles Urban and directed by F. Martin Duncan .
A gentleman is put off his lunch when he holds up a magnifying glass and sees a microscopic view of the cheese mites in his Stilton cheese sandwich.
The film "was the sensation of the first public programme of scientific films in Britain shown at the Alhambra Music Hall in Leicester Square, London, in August 1903". According to Michael Brooke of BFI Screenonline, "its claim to being scientific lay in its being shot through a microscope, revealing to a lay audience sights that would normally only have been available to owners of microscopes." [ 1 ] [ 2 ]
A complete copy which includes an opening sequence, featuring F. Martin Duncan as the gentleman, was discovered uploaded to YouTube under a different title, and has now been acquired by the British Film Institute . Previously only the sequence showing the cheese mites was known to have survived. | https://en.wikipedia.org/wiki/The_Cheese_Mites |
" The Chemical Basis of Morphogenesis " is an article that the English mathematician Alan Turing wrote in 1952. [ 1 ] It describes how patterns in nature , such as stripes and spirals, can arise naturally from a homogeneous, uniform state. The theory, which can be called a reaction–diffusion theory of morphogenesis , has become a basic model in theoretical biology . [ 2 ] Such patterns have come to be known as Turing patterns . For example, it has been postulated that the protein VEGFC can form Turing patterns to govern the formation of lymphatic vessels in the zebrafish embryo. [ 3 ]
Reaction–diffusion systems have attracted much interest as a prototype model for pattern formation . Patterns such as fronts, spirals, targets, hexagons, stripes and dissipative solitons are found in various types of reaction-diffusion systems in spite of large discrepancies e.g. in the local reaction terms. Such patterns have been dubbed " Turing patterns ". [ 4 ]
Reaction–diffusion processes form one class of explanation for the embryonic development of animal coats and skin pigmentation. [ 5 ] [ 6 ] Another reason for the interest in reaction-diffusion systems is that although they represent nonlinear partial differential equations , there are often possibilities for an analytical treatment. [ 7 ] [ 8 ] [ 9 ] | https://en.wikipedia.org/wiki/The_Chemical_Basis_of_Morphogenesis |
The Chemical Engineer is a monthly chemical engineering technical and news magazine published by the Institution of Chemical Engineers (IChemE). [ 1 ] It has technical articles of interest to practitioners and educators, and also addresses current events in world of chemical engineering including research, international business news and government policy as it affects the chemical engineering community. The magazine is sent to all members of the IChemE and is included in the cost of membership. Some parts of the magazine are available free online, including recent news and a series of biographies “Chemical Engineers who Changed the World”, [ 2 ] although the core and the archive magazine is available only with a subscription. The online magazine also has freely available podcasts .
The formal journal of the IChemE was the “Transactions” which was initially an annual publication. In order to keep members informed a “Quarterly Bulletin- Institution of Chemical Engineers” was issued. When the Transactions became quarterly, the Bulletin was issued as a supplement. In 1956 both changed to bi-monthly and the title was changed to “The Chemical Engineer” with the sub-title “Bulletin of the Institution of Chemical Engineers". It kept the same numbering, so was issue 125. According to the editorial it would contain news and “articles and comments by members, handled less formally than in Transactions , relating both to practical matters arising from experience and to broader aspects of professional life.” [ 3 ]
From 2002 it was published as “TCE” but reverted to its original title with issue 894 in December 2015. [ 4 ] | https://en.wikipedia.org/wiki/The_Chemical_Engineer |
The Circle of Reason ( TCOR ) is a Twin Cities , Minnesota -based international society of theists , atheists , conservatives , and liberals who espouse the social philosophy of pluralistic rationalism (also plurationalism or methodological rationalism ). [ 1 ] [ 2 ] [ 3 ] [ 4 ] [ 5 ] [ 6 ] [ 7 ]
Pluralistic rationalism is described in cultural media as "commitment to reason[ing], regardless of one's worldview," [ 8 ] and by the society itself as "communal commitment to more consistently practice the basic methodological tenets of a reasoning lifestyle (reality's acceptance, assumption's denial, and emotion's mastery) irrespective of our theological, ethical, cultural or political worldviews." [ 5 ] According to The Circle of Reason, pluralistic rationalism is practiced through encouraging not a particular worldview, but rather factualism, skepticism, and moderationism; and furthermore through discouraging their opposing practices of denialism, dogmatism, and emotionalism – or "denials of reality, unquestioned assumptions (potentially false realities), and emotive arguments or actions (dissociation from reality)." Plurationalist practices include discouraging the verbal, printed or televised use of insults (which the group asserts is immoral because, as ad hominem argumentation, it seeks to "irrationally persuade by evoking emotionality.") Because plurationalists hold that "as a sapient being one's best tool to survive is one's ability to reason," they also claim people's basic universalized moral imperative must then be to likewise "consistently allow, and encourage, others to reason" as well – which, by rationally underpinning social behaviors otherwise considered subjectively emotional (such as compassion, kindness, and nonaggression), they claim represents "the world's first objective moral code." [ 5 ]
Reflecting the plurationalist society's call to "more consistently use everyday reasoning regardless of our worldviews," [ 5 ] its institutional practices have included organizing the United States' first reported "theist + atheist" dialogue group, "Secular Bible Study," for reasoning discussion on the historical context, societal impact and cultural relevance of the Bible and religion, [ 1 ] [ 2 ] [ 9 ] and "Ancient Greek Peripatetic "-style nature walks combined with "transcultural, transbelief reasoning dialogue" on current social issues; [ 1 ] organizing and moderating "Assumptions on the [Minnesota Same-Sex] Marriage Amendment: A Reasoning Forum" for theists, atheists, conservatives & liberals; [ 10 ] [ 11 ] defending a Catholic legislator shunned by his archdiocese for refusing to defund reproductive health clinics; [ 12 ] presenting an address on plurationalism, "Be Sane — Be VERY Sane!" to the "Rally to Restore Sanity Minnesota" at the State Capitol; [ 13 ] [ 14 ] and successfully lobbying the state capital city's Council of Churches to become the first local council of religions in the United States to change the name of its religious " interfaith " dialogue group to "interbelief," to better welcome atheists and secular humanists with no religious faith but with philosophical or ethical beliefs. [ 15 ] [ 16 ] [ 17 ]
The Pluralism Project at Harvard University has described The Circle of Reason as a "promising practice." [ 1 ] [ 2 ] [ 3 ] [ 4 ] | https://en.wikipedia.org/wiki/The_Circle_of_Reason_(society) |
The Clapper is a sound -activated electrical switch , [ 1 ] sold since 1984 by San Francisco , California based Joseph Enterprises, Inc. Joseph Pedott marketed the clapper with the slogan "Clap On! Clap Off! The Clapper!". [ 2 ]
The Clapper plugs into a U.S.-type electrical outlet , and allows control of up to two devices plugged into the Clapper. [ 3 ] An upgraded model, known as the Clapper Plus , includes a remote control function in addition to the original sound-based activation. [ 4 ]
Although meant to activate by clapping , The Clapper can inadvertently be triggered by other noises like dogs barking for example. [ 5 ]
The smart Clapper was invented by Carlile R. Stevens and Dale E. Reamer, and issued U.S. Patent #5493618, had its application filed on 1993-05-07 and was granted on 20 February 1996. [ 6 ] | https://en.wikipedia.org/wiki/The_Clapper |
The Clark Collection of Mechanical Movements is a museum exhibit at the Museum of Science (Boston) . [ 1 ] Built in the 1920s, [ 2 ] it currently shows 120 panels of mechanisms, including gears and models of machines. [ 3 ] The exhibit is constructed in cabinets of 16 square panels, each measuring 15¼ by 15¼ inches, containing one or more movements. [ 4 ]
W.M. Clark, of South Orange, NJ , in a book accompanying the exhibit described himself as a
"hobbyist ... [who] ... through the help of the book '507 Mechanical Movements', acquired the foundation for a mechanical education, without schooling in the regular way." [ 5 ] [ page needed ]
The exhibit, originally titled "Mechanical Wonderland," was made over "20 years" by Mr. Clark in the early 1900s and displayed in "the Boys' Department of a New York department store". [ 5 ]
It was inspired by the book Five Hundred and Seven Mechanical Movements by Henry T. Brown, published in 1869. [ 6 ] | https://en.wikipedia.org/wiki/The_Clark_Collection_of_Mechanical_Movements |
The Cobra Event is a 1998 thriller novel by Richard Preston describing an attempted bioterrorism attack on the United States . The perpetrator of the attack has genetically engineered a virus , called "Cobra", that fuses the incurable and highly contagious common cold with one of the world's most virulent diseases, smallpox . The disease that results from the virus, brainpox, has symptoms that mimic those of Lesch–Nyhan syndrome and the common cold. The book is divided between descriptions of the virus and the government's attempt to stop the imminent threat posed by it.
The book is divided into six sections. The first section, called "Trial", starts with a teenaged girl named Kate Moran who dies violently one day in school. The next section, titled "1969", describes tests done in the 1960s by the U.S. government involving weaponized viruses. The third section, "Diagnosis", describes the autopsy of Kate Moran and introduces the key characters of Dr. Alice Austen, Mark Littleberry, and Will Hopkins. The last three sections—"Decision", "Reachdeep", and "The Operation"—describe these three characters' journeys to discover the source of the lethal Cobra virus.
The virus described in the novel is a fictional chimera that attacks the human brain. The infective agent, code-named "Cobra" by the protagonists, is a recombinant virus made from modified variants of the nuclear polyhedrosis virus (which normally infects moths and butterflies), rhinovirus , and smallpox .
The infection initially presents common cold-like symptoms and a characteristic blistering process in the nose and mouth, before invading the nervous system . Although not as contagious as the influenza virus, it spreads rapidly through the same vectors as the common cold, mainly via airborne particulate matter coming in contact with the mucous membranes of the respiratory system. Although tussis is the primary source of these particles, the inclusion of nuclear polyhedrosis virus allows Cobra to form crystals, which can be easily processed into a fine powder. This powder is used as a delivery mechanism in the novel's terrorist attacks.
The optic nerves of the eye, accessed through the eyelid, and olfactory nerves of the nose provide a direct pathway for the neurotropic Cobra virus to spread to the central nervous system , where the virus takes root. Once present in brain matter, the virus begins to replicate exponentially. Infected brain cells experience growth of viral crystals in their nuclei, eventually leading to lysis of the cell. The brain stem , which controls the basic functions of life, is heavily affected by this growth. The Cobra virus also knocks out the gene for the enzyme hypoxanthine-guanine phosphoribosyltransferase , whose absence causes Lesch–Nyhan syndrome . As a result, patients experience both autocannibalistic urges and increased aggression toward others. These neurological symptoms develop within a matter of hours, eventually resulting in death due to the severe damage to the brain stem. Cobra is so aggressive in its growth that autopsies reveal a brain almost liquefied by cell lysis. Cobra is shown to have a case fatality rate of almost 98%, with only one survivor out of 43 people infected.
President Bill Clinton was reportedly sufficiently impressed by the scenarios described in the book that he asked aides and officials for closer study and suggested more funding for research into bioterrorism threats. However, some variation exists in the assorted accounts of this episode in his administration, about his degree of concern, who was asked to help, the depth of inquiry, the formal status of his orders, and the magnitude of expense involved. [ 1 ] [ 2 ] [ 3 ] [ 4 ] [ 5 ] [ 6 ] | https://en.wikipedia.org/wiki/The_Cobra_Event |
The Combustion Institute is an educational non-profit, international, scientific and engineering society whose purpose is to promote research in combustion science . The institute was established in 1954, and its headquarters are in Pittsburgh , Pennsylvania , United States. The current president of The Combustion Institute is Philippe Dagaut (2021-).
The support of this important field of study spanning many scientific and engineering disciplines is done through the discussion of research findings at regional, national and the biennial international symposia, and through the publication of the Proceedings of the Combustion Institute and the institute's journals, Combustion and Flame and the affiliated journals Progress in Energy and Combustion Science , Combustion Science and Technology and Combustion Theory and Modelling . [ 1 ]
The institute serves as the parent organization for thirty three national sections organized in many countries (the US being divided into three sections) as of 2012: [ 2 ]
In honor of fiftieth anniversary of Combustion Institute, the leading combustion scientists John D. Buckmaster , Paul Clavin , Amable Liñán , Moshe Matalon , Norbert Peters , Gregory Sivashinsky and Forman A. Williams wrote a paper in the Proceedings of the Combustion Institute . [ 3 ]
The international symposium on combustion is organised by the Combustion Institute biennially. The first symposium on combustion was held in 1928 in the United States and the first international symposium on combustion was held on 1948, even though the combustion institute itself was found on 1954. [ 4 ] Thirty seven symposiums has been held so far and the 38th symposium was to be held on 2020 but is postponed to 2021. [ 5 ]
During each International Symposium, The Combustion Institute awards the following: [ 1 ] | https://en.wikipedia.org/wiki/The_Combustion_Institute |
The Control of Nature is a 1989 nonfiction book by John McPhee that chronicles three attempts to control natural processes that had varying success. The book combines three long essays previously published in The New Yorker : "Atchafalaya", "Cooling the Lava", and "Los Angeles Against the Mountains". These respectively describe the Old River Control Structure regulating inflow to the Atchafalaya River ; the Eldfell volcanic eruption of 1973; and debris flow from the San Gabriel Mountains .
In 1980, McPhee traveled with his daughter on a canoe trip on the Atchafalaya River due to her fascination with the novelist Walker Percy . He had conversations with natives about the efforts made by the Army Corps of Engineers in monitoring riverflow in the area. In Vicksburg, Mississippi , a man recommended to McPhee that he research the efforts being undergone to control the debris sliding down from mountains into Los Angeles . When he visited California, a geologist informed him about lava in Iceland. [ 1 ]
The book's title is derived from a sign on the engineering building at the University of Wyoming . Though he believes nature will win, "my book is not an editorial," McPhee said. "It is a description of people defying nature. They may have no choice." [ 1 ] Like all of McPhee's books, The Control of Nature started out as an outline that he proceeded to fill in. [ 2 ]
The book begins by describing how the Atchafalaya River drains 30 percent of the Mississippi River at its source 300 miles upriver from New Orleans . Thanks to its steeper gradient and more direct route, the Atchafalaya seeks to change the course of the Mississippi as has happened in its long geological history. Due to the Mississippi's vital importance to industry, the Army Corps of Engineers constructed a control structure at the Atchafalaya's source to prevent this from occurring and to maintain the 30 percent drainage. McPhee explains how Morgan City, Louisiana would be destroyed if the river's banks increase. Three million cubic feet of water would inundate the town in the case of a hundred-year flood , though the Corps of Engineers has been trying its hardest to build a more stable flood structure. [ 2 ]
All three essays that comprise "The Control of Nature" originally appeared in The New Yorker . [ 3 ] After its publication as a book in 1989, The Control of Nature was McPhee's second-best selling book, after Coming into the Country . [ 2 ] It received generally positive reviews from book critics.
Los Angeles Times critic Jack Miles praised McPhee's "knack of presenting even the most ordinary folks in their best, most ingenious moments." He liked "Los Angeles Against the Mountains" the most out of the three essays. He enjoyed how McPhee explained scientific and engineering concepts so a layperson could understand them. [ 3 ]
Martin Ruess, writing in Technology and Culture , thought that McPhee should have added more interpretation to his descriptions. "McPhee has the poet's knack for the telling point, the metaphor that incisively leads to greater understanding," Ruess wrote. He believed that McPhee underestimated humanity's ability to exert its control on natural settings, since the U.S. infrastructure effectively did this. Ruess concluded that "McPhee's reports from the battlefronts are not as valuable as their implicit message that the control of nature is not nearly as important as knowing one's place in it." [ 4 ] | https://en.wikipedia.org/wiki/The_Control_of_Nature |
The Core Pocket Media Player ( TCPMP ) is a software media player which operates on portable devices and Windows -based PCs. It is discontinued, but still available from the official mirror site. Supported operating systems include Palm OS , Symbian OS , and Microsoft Windows , CE , and Mobile . It is also available on Microsoft's Zune HD via a hack called Liberate . [ 4 ] TCPMP also has hardware accelerated playback for ATI and Intel 2700G mobiles, such as the Tapwave Zodiac and Dell Axim X50v /X51V.
Development of the free version of the software was discontinued by CoreCodec in favour of the commercially licensed CorePlayer , though TCPMP is still regarded as one of the more versatile media players for PocketPC and Palm OS mobile devices.
According to the CoreCodec.com website as of September 2002, the development team planned to continue development and releases of the open source version of the player "offsite"; this code would also be incorporated into the commercial player. [ 5 ] In 2004, on CoreCodec.org, the open source player was released as BetaPlayer 0.01a for Windows CE and Windows Mobile . It was renamed The Core Pocket Media Player in July 2005 upon its release for the Palm OS and Windows CE/Mobile operating systems. [ 1 ] [ 2 ] A release of TCPMP for the Symbian OS has been remarked upon, [ 6 ] [ 7 ] but further information about it is available only in forums.
The TCPMP project page indicates that the development languages used were "assembly, C". [ 8 ] In 2006, CoreCodec Inc. discontinued development of TCPMP to focus on the commercial CorePlayer Platform. [ 9 ]
TCPMP supports many audio, video, and image formats, including AC3 , HE-AAC (later removed), AMR , DivX , FLAC , H.263 , H.264 , JPEG , Monkey's Audio , MJPEG , MPEG-1 , MP2 , MP3 , Musepack , MS-MPEG4-v3 , PNG , Speex , TIFF , TTA, Vorbis , WAV , WavPack and XviD .
It supports many container formats , including 3GP , ASF , AVI , Matroska , MPEG , OGG , OGM and QuickTime . [ 10 ]
On the Windows desktop platform, a third-party codec can support H.264 , [ 11 ] and a third-party plugin can support YouTube videos and other Flash video formats. [ 12 ]
The program received consistently positive reviews for its performance, versatility, and functionality, with minor criticism of user interface issues. HPC:Factor magazine, in evaluating version 0.66, declared it "excellent" while noting a need for improvement in menu space usage, and the "complete lack of documentation." [ 3 ] Version 0.70 was described as "the best, free multimedia player for both the Pocket PC and the Palm OS platform" in Smartphone & Pocket PC magazine in November 2005. [ 13 ] The 2006 Treo Central review gave it a score of 4/5 for use on Palm OS-equipped Treo devices, with "a pretty cool and logical interface, albeit with some drawbacks", "supporting almost every video encapsulation known to humankind" without conversion prior to playback. [ 14 ] SmartDevice Central reviewed version 0.71 on the Palm Treo 700 in 2007, called it "impressive", and "a solid piece of software," while summarizing its user interface as resembling "a black-and-white Macintosh app from the late 1980s, it has absolutely no eye candy whatsoever." [ 6 ]
After CoreCodec Inc. discontinued development of TCPMP in 2006, renamed it CorePlayer, and developed it for commercial sale, one review referred to the "quirky but rock solid TCPMP" as "bulletproof", compared to a very early version of the new player (later reviews mentioned no problems with stability). [ 9 ] | https://en.wikipedia.org/wiki/The_Core_Pocket_Media_Player |
" The Crabfish " ( Roud 149, also known as "The Crayfish" , "The Codfish" , "The Old She-Crab" , "The Lobster" , "Tommy Doddler" , or "A Combat Between an Ale-Wife and a Sea Crab" ) is a ribald humorous folk song of English origin. [ 1 ] It is one of the most widespread English-language folk songs, being found in almost every English-speaking country and still being sung to the present day. The oldest known mention is in the seventeenth century, appearing in Bishop Percy's Folio Manuscript as a song named "The Sea Crabb" based on an earlier tale. [ 2 ] The moral of the story is that one should look in the chamber pot before using it.
Owing to the coarseness of the lyrics, this ballad was excluded from Francis James Child 's The English and Scottish Popular Ballads as well as many other academic publications. [ 3 ] [ 1 ]
A man brings a crabfish (most likely a common lobster ) home as a gift for his wife and puts it in the chamber pot. Some time in the night his wife answers a call of nature and the crustacean grabs her private parts. In the ensuing scuffle the husband gets bitten too in some versions. [ 4 ]
This is one version of the song, as sung by John Roberts and Tony Barrand : [ 1 ]
Fisherman, fisherman, standing by the sea Have you got a crayfish that you can sell to me By the way side high diddly aye do Yes sir, yes sir, that indeed I do I have got a crayfish that I can sell to you By the way side high diddly aye do Well, I took the crayfish home, and I thought he'd like a swim So I filled up the chamber pot, and I threw the bugger in By the way side high diddly aye do In the middle of the night, I thought I'd have a fit When my old lady got up to a-have a shit By the way side high diddly aye do Husband, husband, she cried out to me The devil's in the chamber pot, and he's got hold of me By the way side high diddly aye do Children, children, bring the looking glass Come and see the crayfish that bit your mother's arse By the way side high diddly aye do Children, children, did you hear the grunt Come and see the crayfish that bit your mother's cunt By the way side high diddly aye do It's the ending of me story; I don't have any more I've an apple in me pocket, and you can have the core By the way side high diddly aye do
"Johnny Daddlum" is the Irish version of this song. [ 5 ] There are some variants in which the coarse language is more clear-cut than in others, and other variants where the language is masked with another word yet implied through the rhyme. In some variants the wife is pregnant , having previously told her husband about her craving to eat crabfish meat. | https://en.wikipedia.org/wiki/The_Crabfish |
The Creepy Line is a 2018 American documentary exploring the influence Google and Facebook have on public opinion, and the power the companies have that is not regulated or controlled by national government legislation. [ 2 ]
The title is taken from a quote by Eric Schmidt , who when describing Google's use of personal information stated that the company did not cross the line that an ordinary user would find unacceptable. [ 3 ] [ 4 ] It was released on December 18, 2018.
The film contrasts the notion of fake news which is visible, with the invisible ranking or masking of information by Google and Facebook, and features headshot interviews with Robert Epstein , Jaron Lanier , Jordan Peterson and Peter Schweizer .
The Verge reviewed The Creepy Line , writing that "Despite its dark name, The Creepy Line appeals to the comforting logic of conspiracy: when something goes wrong in life, it’s because an all-powerful entity thinks you’re important enough to attack." [ 5 ] | https://en.wikipedia.org/wiki/The_Creepy_Line |
The Daily Minor Planet is a citizen science project run by the Zooniverse and The Catalina Sky Survey with a funding grant from NASA , to use citizen science volunteer classifications to discover asteroids with recent data from the G96 Mount Lemmon Survey 1.52 m (60 in) cassegrain reflector telescope. [ 2 ] [ 3 ] [ 4 ] [ 5 ] The main objective of the project is to search for undiscovered asteroids in order to protect the planet by locating potentially harmful Near-Earth asteroids . [ 6 ] [ 7 ] [ 8 ] [ 9 ]
This astronomy -related article is a stub . You can help Wikipedia by expanding it . | https://en.wikipedia.org/wiki/The_Daily_Minor_Planet |
The Daily WTF (also called Worse Than Failure from February to December 2007) is a humorous blog dedicated to "Curious Perversions in Information Technology ". The blog, run by Alex Papadimoulis, "offers living examples of code that invites the exclamation ‘ WTF !?'" (What The Fuck!?) [ 2 ] and "recounts tales of disastrous development, from project management gone spectacularly bad to inexplicable coding choices." [ 3 ]
In addition to horror stories, The Daily WTF "serve[s] as [a] repositor[y] of knowledge and discussion forums for inquisitive web designers and developers" [ 4 ] and has introduced several anti-patterns , including Softcoding , [ 5 ] the Inner-Platform Effect , [ 6 ] and IHBLRIA [ 7 ] (Invented Here But Let's Reinvent It Anyway).
The site also has an associated "Edition Française", a French-language edition headed up by Jocelyn Demoy, launched in March 2008, [ 8 ] as well as a Polish edition.
The website was started on 17 May 2004, when Papadimoulis posted an entry entitled "Your Daily Cup of WTF" on his blog as a means of simply complaining about the quality of development at his then current employer. [ 9 ] On his third such post, a reader of his blog suggested that he start a new website dedicated exclusively to such humorous "bad code" postings. [ 10 ] A few days later, he registered TheDailyWTF.com domain name and began posting stories from readers of the site.
The content of the site kept evolving, and the body of articles was split into several columns. On 2 November 2006 Papadimoulis starting running code samples as articles entitled the "Code Snippets of the Day", "CodeSOD" for short. Originally edited by Tim Gallagher, the column was taken over by Derrick Pallas (now the sole editor of CodeSOD) as well as Devin Moore and Mike Nuss on 2 January 2007. On 12 February 2007 Jake Vinson started a new column, "Error'd", based on the old monthly series "Pop-Up Potpourri".
The site was renamed to "Worse Than Failure" on 24 February 2007 because "'Daily' and 'What The F*' didn’t quite describe it anymore". Papadimoulis also did not enjoy explaining the meaning "WTF" to people unfamiliar to the phrase, as it contains profanity. [ 11 ] This was not without controversy, and some readers threatened to stop reading the site because of this. [ 12 ] The change was reverted on December 12, 2007, [ 13 ] after a short and tongue-in-cheek stint as "The Daily Worse Than Failure". [ 14 ]
Olympiad of Misguided Geeks at Worse Than Failure (abbr. OMG WTF ) was a programming contest to "solve an incredibly simple problem using the most obscenely convoluted way imaginable". [ 15 ] It was started by Alex Papadimoulis because he wanted "to try out something new on [the] site." Contestants for the OMGWTF contest were encouraged to focus on writing "clever code" (code which is unconventional and solves a problem that may or may not be solvable with conventional means) as opposed to "ugly code" (single letter variable names, no subroutines, and so on).
The goal of the first (and so far, only) contest was to "implement the logic for a four-function calculator." It ran from 24 April 2007 to 14 May 2007 [ 16 ] and received over 350 submissions [ 17 ] which were then judged by popular technology bloggers Raymond Chen , Jeremy Zawodny and Joel Spolsky . [ 18 ]
The winning entry was Stephen Oberholtzer's "Buggy 4-Function Calculator", [ 19 ] [ 20 ] which, according to judge Joel Spolsky "best exemplifies what real-world code looks like ... [it's] not just bad code, [it's] believable bad code." In addition to "a High-Resolution JPEG of an Official Olympiad of Misguided Geeks at Worse Than Failure First Prize Trophy," the winner received a 15-inch MacBook Pro.
In addition to the mostly anonymous stories, several prominent figures have written stories they’ve encountered in their professional experience such as Blake Ross who wrote of the failure of Netscape 7 . [ 21 ] | https://en.wikipedia.org/wiki/The_Daily_WTF |
The Day the Earth Smiled is a composite photograph taken by the NASA spacecraft Cassini on July 19, 2013. During an eclipse of the Sun , the spacecraft turned to image Saturn and most of its visible ring system , as well as Earth and the Moon as distant pale dots. The spacecraft had twice taken similar photographs (in 2006 and 2012) in its previous nine years in orbit around the planet. The name also refers to the activities associated with the event, as well as to the photographic mosaic created from it. [ 1 ]
Conceived by the planetary scientist Carolyn Porco , the imaging team leader for Cassini , the concept called for the people of the world to reflect on their place in the universe, to marvel at life on Earth, and, at the time the pictures were taken, to look up and smile in celebration. [ 2 ] [ 3 ]
The final mosaic captured on July 19, processed at the Cassini Imaging Central Laboratory for Operations (CICLOPS), was released to the public on November 12, 2013. [ 4 ] [ 5 ] The photograph includes Earth, Mars , Venus , and many Saturnian moons . [ 6 ] A higher-resolution image, depicting Earth and the Moon as distinct points of light, was taken with Cassini 's narrow-angle camera and was released shortly afterwards.
The Cassini probe took images of Earth and the Moon from close to 3.4 billion kilometres away (2.1 billion miles) at 21:27 UTC , July 19, 2013. A number of activities were planned to celebrate the occasion:
Raw images from Cassini were received on Earth shortly after the event, and a couple of processed images—a high-resolution image of the Earth and the Moon, and a small portion of the final wide-angle mosaic showing the Earth—were released to the public a few days following the July 19 imaging sequence. [ 11 ] [ 12 ]
Processing of the full mosaic took place at CICLOPS under Porco's direction over the course of approximately two months. [ 13 ] During the four hours it took Cassini to image the entire 647,808 kilometres (402,529 mi)-wide scene, the spacecraft captured a total of 323 images, 141 of which were used in the mosaic. [ 6 ] NASA revealed that this imaging marked the first time four planets – Saturn, Earth, Mars, and Venus – had been captured at once in visible light by the Cassini craft. [ 14 ] It was also the first time the people of Earth knew in advance that their picture would be taken from the outer Solar System. [ 3 ]
NASA's official release of the final The Day the Earth Smiled mosaic on November 12, 2013, was met with much fanfare in news media outlets around the world. [ 4 ] [ 5 ] [ 15 ] [ 16 ] [ 17 ] The image graced the front page of The New York Times the following day. [ 18 ] [ 19 ] Public figures including media producer Seth MacFarlane lauded the image. [ 20 ] The mosaic was also presented by Carolyn Porco, and dedicated to the late astronomer Carl Sagan , at a ceremony at the Library of Congress in honor of its acquisition of Sagan's papers. [ 21 ] In addition, a collage of images submitted by 1,600 members of the public to NASA's Wave at Saturn campaign was released on November 12. [ 22 ] | https://en.wikipedia.org/wiki/The_Day_the_Earth_Smiled |
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