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ENGERIX-B (produced by GSK) and RECOMBIVAX HB (produced by merck) are two recombinant subunit vaccines licensed for the protection against hepatitis B. Both contain HBsAg harvested and purified from Saccharomyces cerevisiae and are formulated as a suspension of the antigen adjuvanted with alum.
Antibody concentration ≥10mIU/mL against HBsAg are recognized as conferring protection against hepatitis B infection.
It has been shown that primary 3-dose vaccination of healthy individuals is associated with ≥90% seroprotection rates for ENGERIX-B, despite decreasing with older age. Lower seroprotection rates are also associated with presence of underlying chronic diseases and immunodeficiency. Yet, GSK HepB still has a clinically acceptable safety profile in all studied populations. | 1 | Applied and Interdisciplinary Chemistry |
The kinetic theory of gases deals not only with gases in thermodynamic equilibrium, but also very importantly with gases not in thermodynamic equilibrium. This means using Kinetic Theory to consider what are known as "transport properties", such as viscosity, thermal conductivity, mass diffusivity and thermal diffusion.
In its most basic form, Kinetic gas theory is only applicable to dilute gases. The extension of Kinetic gas theory to dense gas mixtures, Revised Enskog Theory, was developed in 1983-1987 by E. G. D. Cohen, J. M. Kincaid and M. Lòpez de Haro, building on work by H. van Beijeren and M. H. Ernst. | 0 | Theoretical and Fundamental Chemistry |
The Hatta number (Ha) was developed by Shirôji Hatta (1895-1973 ) in 1932, who taught at Tohoku University from 1925 to 1958. It is a dimensionless parameter that compares the rate of reaction in a liquid film to the rate of diffusion through the film. For a second order reaction (), the maximum rate of reaction assumes that the liquid film is saturated with gas at the interfacial concentration ; thus, the maximum rate of reaction is .
For a reaction order in and order in :
For gas-liquid absorption with chemical reactions, a high Hatta number indicates the reaction is much faster than diffusion. In this case, the reaction occurs within a thin film, and the surface area limits the overall rate. Conversely, a Hatta number smaller than unity suggests the reaction is the limiting factor, and the reaction takes place in the bulk fluid, requiring larger volumes. | 1 | Applied and Interdisciplinary Chemistry |
Structure-based virtual screening approach includes different computational techniques that consider the structure of the receptor that is the molecular target of the investigated active ligands. Some of these techniques include molecular docking, structure-based pharmacophore prediction, and molecular dynamics simulations. Molecular docking is the most used structure-based technique, and it applies a scoring function to estimate the fitness of each ligand against the binding site of the macromolecular receptor, helping to choose the ligands with the most high affinity. Currently, there are some webservers oriented to prospective virtual screening. | 1 | Applied and Interdisciplinary Chemistry |
In addition to various primary data formats (e.g. GPML, BioPAX, Reactome, KEGG, and RDF), WikiPathways supports a variety of ways to integrate and interact with pathway content. These include directed link-outs, image maps, RSS feeds and deep web services. This enables reuse in projects like COVID19 Disease Map.
WikiPathways content is used to annotate and cross-link Wikipedia articles covering various genes, proteins, metabolites and pathways. Here are a few examples:
* Citric acid cycle § Interactive pathway map
* Articles that link to Citric acid cycle template
* :Category:WikiPathways templates | 1 | Applied and Interdisciplinary Chemistry |
Members of the HNF4 subfamily are nuclear receptors and bind to DNA either as homodimers or RXR heterodimers.
* HNF4α/TCF14/MODY1
* HNF4γ | 1 | Applied and Interdisciplinary Chemistry |
A run to be inspected will either start from an access pipe leading at an angle down to the sewer and then run downstream to a manhole, or will run between manholes.
The service truck is parked above the access point of the pipe. The camera tractor, with a flexible cable attached to the rear, is then lowered into the pipeline. The tractor is moved forward so that it is barely inside of the pipeline. A "down-hole roller" is set up between the camera tractor and the cable reel in the service truck, preventing cable damage from rubbing the top of the pipeline. The operator then retires to the inside of the truck and begins the inspection, remotely operating the camera tractor from the truck. When the inspection is complete or the camera cable is fully extended, the camera tractor is put in reverse gear and the cable is wound up simultaneously. When the camera tractor is near the original access point, the downhole roller is pulled up and the camera tractor is moved into the access point and pulled up to the service truck. A tractor may be used to inspect a complete blockage or collapse that would prevent using a fish and rope as described below. | 1 | Applied and Interdisciplinary Chemistry |
Proteins or polypeptides are polymers of amino acids. A protein is created by ribosomes that "read" RNA that is encoded by codons in the gene and assemble the requisite amino acid combination from the genetic instruction, in a process known as translation. The newly created protein strand then undergoes posttranslational modification, in which additional atoms or molecules are added, for example copper, zinc, or iron. Once this post-translational modification process has been completed, the protein begins to fold (sometimes spontaneously and sometimes with enzymatic assistance), curling up on itself so that hydrophobic elements of the protein are buried deep inside the structure and hydrophilic elements end up on the outside. The final shape of a protein determines how it interacts with its environment.
Protein folding consists of a balance between a substantial amount of weak intra-molecular interactions within a protein (Hydrophobic, electrostatic, and Van Der Waals Interactions) and protein-solvent interactions. As a result, this process is heavily reliant on environmental state that the protein resides in. These environmental conditions include, and are not limited to, temperature, salinity, pressure, and the solvents that happen to be involved. Consequently, any exposure to extreme stresses (e.g. heat or radiation, high inorganic salt concentrations, strong acids and bases) can disrupt a protein's interaction and inevitably lead to denaturation.
When a protein is denatured, secondary and tertiary structures are altered but the peptide bonds of the primary structure between the amino acids are left intact. Since all structural levels of the protein determine its function, the protein can no longer perform its function once it has been denatured. This is in contrast to intrinsically unstructured proteins, which are unfolded in their native state, but still functionally active and tend to fold upon binding to their biological target. | 1 | Applied and Interdisciplinary Chemistry |
Positive charges of soil minerals can retain anions by the same principle as cation exchange. The surfaces of kaolinite, allophane and iron and aluminium oxides often carry positive charges. In most soils the cation-exchange capacity is much greater than the anion-exchange capacity, but the opposite can occur in highly weathered soils, such as ferralsols (oxisols). | 0 | Theoretical and Fundamental Chemistry |
Homing endonucleases differ from Type II restriction enzymes in the several respects:
* Whereas Type II restriction enzymes bind short, usually symmetric, recognition sequences of 4 to 8 bp, homing endonucleases bind very long and in many cases asymmetric recognition sequences spanning 12 to 40 bp.
* Homing endonucleases are generally more tolerant of substitutions in the recognition sequence. Minor variations in the recognition sequence usually decrease the activity of homing endonucleases, but often do not completely abolish it as often occurs with restriction enzymes.
* Homing endonucleases share structural motifs that suggest there are four families, whereas it has not been possible to determine simply recognisable and distinguishable families of Type II restriction enzymes.
* Homing endonucleases act as monomers or homodimers, and often require associated proteins to regulate their activity or form ribonucleoprotein complexes, wherein RNA is an integral component of the catalytic apparatus. Type II restriction enzymes can also function alone, as monomers or homodimers, or with additional protein subunits, but the accessory subunits differ from those of the homing endonucleases. Thus, they can require restriction, modification, and specificity subunits for their action.
* Finally, homing endonucleases have a broader phylogenetic distribution, occurring in all three biological domains—the archaea, bacteria and eukarya. Type II restriction enzymes occur only in archaea, bacteria and certain viruses. Homing endonucleases are also expressed in all three compartments of the eukaryotic cell: nuclei, mitochondria and chloroplasts. Open reading frames encoding homing endonucleases have been found in introns, inteins, and in freestanding form between genes, whereas genes encoding Type II restriction enzyme genes have been found only in freestanding form, almost always in close association with genes encoding cognate DNA modifying enzymes. Thus, while the Type II restriction enzymes and homing endonucleases share the function of cleaving double-stranded DNA, they appear to have evolved independently. | 1 | Applied and Interdisciplinary Chemistry |
While teaching chemistry in Riga Polytechnic Institute, Wilhelm Ostwald became convinced that certain reactions could only be explained in terms of energy, without the need of invoking the hypothesis of the existence of atoms. He was inspired by Josiah Willard Gibbs's work on thermodynamics. During an inaugural lecture in 1887 in Leipzig University, Ostwald outlined his program of energetics as an alternative to atomic theory. In his second edition of his textbook on physical chemistry of 1892, he stressed that energetic ideas should avoid all atomistic considerations. He opposed the reduction of chemistry to mechanics and advocated for the reduction of mass and matter to energy.
In parallel, Georg Helm published his energy principle in The Theory of Energy () in 1887, as an extension to the principle of conservation of energy. In his essay of 1890, he proposed to reduce mechanics to energetics by means of his principle. In 1892, he proposed to do the same for electricity and magnetism. His principle can be written as
where dU is a change in the internal energy of a system, T is the temperature, dS is a change in the entropy, p is the pressure and dV a change in volume. This principle recovers the first law of thermodynamics only when the equality holds. Helm changed the equal sign into an inequality in the hope to account for irreversible processes. | 1 | Applied and Interdisciplinary Chemistry |
The Sheild Professorship of Pharmacology is the senior professorship in pharmacology at the University of Cambridge. It is named in honour of Marmaduke Sheild.
The position was originally established on 7 June 1946 as a personal chair for the tenure of Ernest Basil Verney. On 11 March 1961 the professorship was re-established on a permanent basis. | 1 | Applied and Interdisciplinary Chemistry |
In this effort one of strychnine's many degradation products was synthesised first (the relay compound), a compound also available in several steps from another degradation product called the Wieland-Gumlich aldehyde. In the final leg strychnine itself was synthesised from the relay compound. | 0 | Theoretical and Fundamental Chemistry |
Various degrees of hypothermia may be deliberately induced in medicine for purposes of treatment of brain injury, or lowering metabolism so that total brain ischemia can be tolerated for a short time. Deep hypothermic circulatory arrest is a medical technique in which the brain is cooled as low as 10 °C, which allows the heart to be stopped and blood pressure to be lowered to zero, for the treatment of aneurysms and other circulatory problems that do not tolerate arterial pressure or blood flow. The time limit for this technique, as also for accidental arrest in ice water (which internal temperatures may drop to as low as 15 °C), is about one hour. | 1 | Applied and Interdisciplinary Chemistry |
Enalapril has an L-proline moiety as a part of the molecule which is responsible for the oral bioavailability of the drug. It is a pro-drug, which means that it exerts its function after being metabolized. The "-OCH2CH3" part of the molecule will split during the metabolism and at the carbon will be a carboxylate, which then interacts with the Zn+2 site of the ACE enzyme. This structural feature and mechanism of metabolism that must occur before the drug can inhibit the enzyme explains why it has a greater duration of action than another similar drug used for the same indication, Captopril. Duration of effect is dose-related; at recommended doses, antihypertensive and haemodynamic effects have been shown to be maintained for at least 24 hours. Enalapril has a slower onset of action than Captopril but a greater duration of action. However, unlike Captopril, Enalapril does not have a thiol moiety. | 0 | Theoretical and Fundamental Chemistry |
Nanocomposite hydrogels (NC gels) are nanomaterial-filled, hydrated, polymeric networks that exhibit higher elasticity and strength relative to traditionally made hydrogels. A range of natural and synthetic polymers are used to design nanocomposite network. By controlling the interactions between nanoparticles and polymer chains, a range of physical, chemical, and biological properties can be engineered. The combination of organic (polymer) and inorganic (clay) structure gives these hydrogels improved physical, chemical, electrical, biological, and swelling/de-swelling properties that cannot be achieved by either material alone. Inspired by flexible biological tissues, researchers incorporate carbon-based, polymeric, ceramic and/or metallic nanomaterials to give these hydrogels superior characteristics like optical properties and stimulus-sensitivity which can potentially be very helpful to medical (especially drug delivery and stem cell engineering) and mechanical fields.
Nanocomposite hydrogels are not to be confused with nanogel, a nanoparticle composed of a hydrogel. | 0 | Theoretical and Fundamental Chemistry |
Many alkoxides can be prepared by anodic dissolution of the corresponding metals in water-free alcohols in the presence of electroconductive additive. The metals may be Co, Ga, Ge, Hf, Fe, Ni, Nb, Mo, La, Re, Sc, Si, Ti, Ta, W, Y, Zr, etc. The conductive additive may be lithium chloride, quaternary ammonium halide, or other. Some examples of metal alkoxides obtained by this technique: , , , , , , and . | 0 | Theoretical and Fundamental Chemistry |
Robert Bob Ramage FRS (4 October 1935 — 16 October 2019) was an organic chemist, born in Glasgow, who specialised in the synthesis and biosynthesis of natural products, peptides, and proteins.
Following his undergraduate degree in chemistry and the University of Glasgow, he stayed on for a PhD in organic chemistry. After his time at Glasgow, he followed his interest in natural products synthesis to Harvard and then Basel, before taking up a lectureship in organic chemistry at the University of Liverpool where his attention was drawn to peptides.
His peptide synthesis research continued at the University of Manchester Institute of Science and Technology (UMIST), where he also served as head of department. He returned to Scotland in 1984, taking up the Forbes chair of organic chemistry at the University of Edinburgh, where he remained until retirement in 2000.
Outside of academia, in 1994 he founded the company Albachem, which utilised his work with peptides.
He was elected Fellow of the Royal Society of Chemistry (1977), Royal Society of Edinburgh (1986), and the Royal Society (1992). | 0 | Theoretical and Fundamental Chemistry |
In Sweden, it is legal to produce fermented water and there is no upper limit on the alcohol volume produced from the yeast. | 1 | Applied and Interdisciplinary Chemistry |
The deuteron has spin +1 ("triplet state") and is thus a boson. The NMR frequency of deuterium is significantly different from common light hydrogen. Infrared spectroscopy also easily differentiates many deuterated compounds, due to the large difference in IR absorption frequency seen in the vibration of a chemical bond containing deuterium, versus light hydrogen. The two stable isotopes of hydrogen can also be distinguished by using mass spectrometry.
The triplet deuteron nucleon is barely bound at E = , and none of the higher energy states are bound. The singlet deuteron is a virtual state, with a negative binding energy of . There is no such stable particle, but this virtual particle transiently exists during neutron-proton inelastic scattering, accounting for the unusually large neutron scattering cross-section of the proton. | 0 | Theoretical and Fundamental Chemistry |
Auer von Welsbach then started work on development of metal-filament mantles, first with platinum wiring, and then osmium. Osmium is very difficult to work with, but he developed a new method, which mixed osmium oxide powder with rubber or sugar into a paste, which is then squeezed through a nozzle and fired. The paste burns away, leaving a fine wire of osmium.
Although originally intended to be a new mantle, it was during this period that electricity was being introduced into the market, and he started experimenting with ways to use the filaments as a replacement for the electric arc light. He worked on this until finally developing a workable technique in 1898 and started a new factory to produce his Auer-Oslight, which he introduced commercially in 1902. The metal-filament light bulb was a huge improvement on the existing carbon-filament designs, lasting much longer, using about half the electricity for the same amount of light, and being much more robust. | 1 | Applied and Interdisciplinary Chemistry |
Permanent mold casting is a metal casting process that employs reusable molds ("permanent molds"), usually made from metal. The most common process uses gravity to fill the mold. However, gas pressure or a vacuum are also used. A variation on the typical gravity casting process, called slush casting, produces hollow castings. Common casting metals are aluminum, magnesium, and copper alloys. Other materials include tin, zinc, and lead alloys and iron and steel are also cast in graphite molds. Permanent molds, while lasting more than one casting still have a limited life before wearing out. | 1 | Applied and Interdisciplinary Chemistry |
Catalytic triads perform covalent catalysis via an acyl-enzyme intermediate. If this intermediate is resolved by water, the result is hydrolysis of the substrate. However, if the intermediate is resolved by attack by a second substrate, then the enzyme acts as a transferase. For example, attack by an acyl group results in an acyltransferase reaction. Several families of transferase enzymes have evolved from hydrolases by adaptation to exclude water and favour attack of a second substrate. In different members of the α/β-hydrolase superfamily, the Ser-His-Asp triad is tuned by surrounding residues to perform at least 17 different reactions. Some of these reactions are also achieved with mechanisms that have altered formation, or resolution of the acyl-enzyme intermediate, or that don't proceed via an acyl-enzyme intermediate.
Additionally, an alternative transferase mechanism has been evolved by amidophosphoribosyltransferase, which has two active sites. In the first active site, a cysteine triad hydrolyses a glutamine substrate to release free ammonia. The ammonia then diffuses though an internal tunnel in the enzyme to the second active site, where it is transferred to a second substrate. | 1 | Applied and Interdisciplinary Chemistry |
A Flettner rotor is a smooth cylinder with disc end plates which is spun along its long axis and, as air passes at right angles across it, the Magnus effect causes an aerodynamic force to be generated in the direction perpendicular to both the long axis and the direction of airflow. The rotor sail is named after the German aviation engineer and inventor Anton Flettner, who started developing the rotor sail in the 1920s.
In a rotor ship, the rotors stand vertically and lift is generated at right angles to the wind, to drive the ship forwards.
In a rotor airplane, the rotor extends sideways in place of a wing and upwards lift is generated. | 1 | Applied and Interdisciplinary Chemistry |
In organosulfur chemistry, a thioketal is the sulfur analogue of a ketal (), with one of the oxygen replaced by sulfur (as implied by the thio- prefix), giving the structure . A dithioketal has both oxygens replaced by sulfur ().
Thioketals can be obtained by reacting ketones () or aldehydes () with thiols ().
An oxidative cleavage mechanism has been proposed for dithioketals, which involves thioether oxidation, the formation of thionoiums, and hydrolysis, resulting in the formation of aldehyde and ketone products.
Thioketal moieties are found to be responsive to reactive oxygen species (ROS). In the presence of ROS, thioketals can be selectively cleaved. ROS successfully cleave heterobifunctional thioketal linkers, which have been found to have therapeutic potential, as they can produce ROS-responsive agents with two different functionalities.
Ketones can be reduced at neutral pH via conversion to thioketals; the thioketal prepared from the ketone can be easily reduced by catalytic hydrogenation using Raney nickel in a reaction known as the Mozingo reduction. | 0 | Theoretical and Fundamental Chemistry |
The members of the LDLR family are characterized by distinct functional domains present in characteristic numbers. These modules are:
* LDL receptor type A (LA) repeats of 40 residues each, displaying a triple-disulfide-bond-stabilized negatively charged surface; certain head-to-tail combinations of these repeats are believed to specify ligand interactions;
* LDL receptor type B repeats, also known as EGF precursor homology regions, containing EGF-like repeats and YWTD beta propeller domains;
* a transmembrane domain, and
* the cytoplasmic region with (a) signal(s) for receptor internalization via coated pits, containing the consensus tetrapeptide Asn-Pro-Xaa-Tyr (NPxY). This cytoplasmic tail controls both endocytosis and signaling by interacting with the phosphotyrosine binding (PTB) domain-containing proteins.
In addition to these domains which can be found in all receptors of the gene family, LDL receptor and certain isoforms of ApoER2 and VLDLR contain a short region which can undergo O-linked glycosylation, known as O-linked sugar domain. ApoER2 moreover, can harbour a cleavage site for the protease furin between type A and type B repeats which enables production of a soluble receptor fragment by furin-mediated processing. | 1 | Applied and Interdisciplinary Chemistry |
The discovery of X‑rays by Wilhelm Röntgen in 1895 led to widespread experimentation by scientists, physicians, and inventors. Many people began recounting stories of burns, hair loss and worse in technical journals as early as 1896. In February of that year, Professor Daniel and Dr. Dudley of Vanderbilt University performed an experiment involving X-raying Dudleys head that resulted in his hair loss. A report by Dr. H.D. Hawks, of his suffering severe hand and chest burns in an X-ray demonstration, was the first of many other reports in Electrical Review'.
Other experimenters, including Elihu Thomson and Nikola Tesla, also reported burns. Thomson deliberately exposed a finger to an X-ray tube over a period of time and suffered pain, swelling, and blistering. Other effects, including ultraviolet rays and ozone, were sometimes blamed for the damage, and many physicians still claimed that there were no effects from X-ray exposure at all.
Despite this, there were some early systematic hazard investigations, and as early as 1902 William Herbert Rollins wrote almost despairingly that his warnings about the dangers involved in the careless use of X-rays were not being heeded, either by industry or by his colleagues. By this time, Rollins had proved that X-rays could kill experimental animals, could cause a pregnant guinea pig to abort, and that they could kill a foetus. He also stressed that "animals vary in susceptibility to the external action of X-light" and warned that these differences be considered when patients were treated by means of X-rays. | 0 | Theoretical and Fundamental Chemistry |
* 24 August 2007: A large buildup of sea foam occurred on the coast of Yamba, northern New South Wales.
* January–February 2008: Sea foam occurrences at Caloundra and Point Cartwright on Queensland's Sunshine Coast attracted world-wide media attention.
* December 2011: The coast road at Cleveleys, Lancashire was swamped by meter-high drifts of sea foam.
* 2012: During live coverage of Hurricane Irene in Ocean City, Maryland, Tucker Barnes was covered in sea foam.
* 24–25 September 2012: Following storms and high winds, the beach front of the Footdee area of Aberdeen was engulfed with sea foam.
* 27–28 January 2013: The Sunshine Coast in Queensland, Australia had masses of foam wash up on land from ex-tropical cyclone Oswald.
* June 2016: Sea foam occurred across the East coast of Australia, whipped up by storms.
* 28 March 2017: Sea foam was generated by Cyclone Debbie at Sarina Beach in Queensland, Australia.
* 16 October 2017: Hurricane Ophelia covered Cleveleys, Lancashire with spume.
* January 2018: Storm Eleanor causes widespread foam to appear across coastal Europe.
* 11 October 2019: Subtropical storm Melissa brought sea foam to Nantasket Beach in Hull, Massachusetts.
* 21 January 2020: Storm Gloria floods Tossa de Mar, Spain, with thick sea foam on top of major flooding.
* 11 May 2020: Five surfers die in The Netherlands, presumably upon drowning after becoming disoriented in over 2 meters thick sea foam.
* 13 July 2020: The Cape Town storm, South Africa | 0 | Theoretical and Fundamental Chemistry |
Chromosome jumping enables two ends of a DNA sequence to be cloned without the middle section. Genomic DNA may be partially digested using restriction endonuclease and with the aid of DNA ligase, the fragments are circularized at low concentration. From a known sequence, a primer is designed to sequence across the circularized junction. This primer is used to jump 100 kb-300 kb intervals: a sequence 100 kb away would have come near the known sequence on circularization, it permits jumping and sequencing in an alternative manner. Thus, sequences not reachable by chromosome walking can be sequenced. Chromosome walking can also be used from the new jump position (in either direction) to look for gene-like sequences, or additional jumps can be used to progress further along the chromosome. Combining chromosome jumping to chromosome walking through the chromosome allows bypassing repetitive DNA for the search of the target gene. | 1 | Applied and Interdisciplinary Chemistry |
Delayed tissue injury with impaired wound healing capability often develops after receiving doses in excess of 65 Gy. A diffuse injury pattern due to the external beam radiotherapys holographic isodosing occurs. While the targeted tumor receives the majority of radiation, healthy tissue at incremental distances from the center of the tumor are also irradiated in a diffuse pattern due to beam divergence. These wounds demonstrate progressive, proliferative endarteritis, inflamed arterial linings that disrupt the tissues blood supply. Such tissue ends up chronically hypoxic, fibrotic, and without an adequate nutrient and oxygen supply. Surgery of previously irradiated tissue has a very high failure rate, e.g. women who have received radiation for breast cancer develop late effect chest wall tissue fibrosis and hypovascularity, making successful reconstruction and healing difficult, if not impossible. | 0 | Theoretical and Fundamental Chemistry |
The high intensity of the Jameson Cell means that it is much shorter than conventional column flotation cells (see Figure 1), and it does not require air compressors to aerate the suspension of ground ore particles and water (known as a slurry or pulp) in the flotation cell. The lack of a requirement for compressed air and the lack of moving parts means that power consumption is less than for the equivalent mechanical or conventional column flotation cell.
In contrast to most types of flotation cell, the Cell introduces the feed and the air to the Cell in a combined stream via one or more cylindrical columns referred to as "downcomers". Other types of flotation cell typically introduce the feed and the air separately to the cell.
The Cell produces fast mineral flotation rates, especially for very fine mineral particles. It produces high concentrate grades from fast floating liberated particles and is able to do this from a single stage of flotation. The high carrying capacity of the Jameson Cell is particularly beneficial when high yields (mass pulls) are required, such as in recleaning in metals flotation and in the flotation of metallurgical coal, where yields can exceed 80%.
The Cell was initially developed as a lower-cost alternative to conventional column flotation cells for recovering fine particles, and was first used in the Mount Isa lead–zinc concentrator in 1988. Since then, use of the technology has spread to include coal flotation, base and precious metal flotation, potash flotation, oil sands flotation, molybdenum flotation, graphite flotation and cleaning solvent extraction liquors. Xstrata Technology, Glencore Xstratas technology marketing arm, listed 328 Jameson Cell installations in May 2013. Cells have been installed by 94 companies in 27 countries. Today, the technology is the standard in the Australian Coal Industry where well over one hundred Cells have been installed to recover coal fines. It is mainly used in metals applications to solve final grade and capacity issues from conventional cell cleaner circuits. It has found a niche in transforming traditional circuit designs where its inclusion allows cleaner circuits to be designed with fewer cells in a smaller footprint, while achieving cleaner and/or higher grade concentrates. It has also made possible the recovery of previously discarded fine materials, such as coal and phosphate fines, thereby increasing the efficiency and extending the life of the worlds non-renewable natural resources. | 1 | Applied and Interdisciplinary Chemistry |
In 1978, David J. Galas and Albert Schmitz developed the DNA footprinting technique to study the binding specificity of the lac repressor protein. It was originally a modification of the Maxam-Gilbert chemical sequencing technique. | 1 | Applied and Interdisciplinary Chemistry |
Evekeo is an FDA-approved medication that contains racemic amphetamine sulfate (i.e., 50% levoamphetamine sulfate and 50% dextroamphetamine sulfate). It is approved for the treatment of narcolepsy, ADHD, and exogenous obesity. The orally disintegrating tablets are approved for the treatment of attention deficit hyperactivity disorder (ADHD) in children and adolescents aged six to 17 years of age. | 0 | Theoretical and Fundamental Chemistry |
The period of the iconoclasts synchronised with the reign of the Frankish emperor Charlemagne, whose power was felt throughout western Europe. Some of the craftsmen who were forced to leave Byzantium were welcomed by him in his capitals of Cologne and Aix-la-Chapelle and their influence was also felt in France. Another stream passed by way of the Mediterranean to Italy, where the old classical art had decayed owing to the many national calamities, and here it brought about a revival. In the Rhineland and elsewhere in Europe the terms "Rhenish-Byzantine" and "Romanesque" applied to architecture and works of art generally, testify to the provenance of the style of this and the succeeding period. The bronze parapet of Aachen Cathedral is of classic design and probably dates from Charlemagne's time.
All through the Middle Ages the use of bronze continued on a great scale, particularly in the 11th and 12th centuries. Bernward, bishop of Hildesheim, a great patron of the arts, had bronze doors, the Bernward Doors, made for St Nicholas' church (afterwards removed to the cathedral) which were set up in 1015; great doors were made for Augsburg somewhere between 1060 and 1065, and for Mainz shortly after the year 1000. A prominent feature on several of these doors is seen in finely modelled lion jaws, with conventional manes and with ring hanging from their jaws. These have their counterpart in France and Scandinavia as well as in England, where they are represented by the so-called Sanctuary Knocker at Durham Cathedral.
Provision of elaborate tomb monuments and church furniture gave much work to German and Netherlandish founders. Mention may be made of the seven-branch candlestick at Essen Cathedral made for the Abbess Matilda about the year 1000, and another at Brunswick completed in 1223; also of the remarkable font of the 13th century made for Hildesheim Cathedral at the charge of Wilbernus, a canon of the cathedral. Other fonts are found at Brandenburg and Würzburg. Vast numbers of bronze and brass ewers, holy-water vessels, reliquaries and candelabra were produced in the Middle Ages. In general, most of the finest work was executed for the Church. An important centre of medieval copper and brass casting (Dutch: geelgieten; literally "yellow casting") was the Meuse Valley, especially in the 12th century. The city of Dinant gave its name to the French term for all types of artistic copper and brass work: dinanderie (see also section "Brass"). After the destruction of the town by Charles the Bold in 1466, many brass workers moved to Maastricht, Aachen and other towns in Germany and even England.
The end of the Gothic period saw some great craftsmen in Germany and the Habsburg Netherlands. The brass worker Aert van Tricht was based in Maastricht but worked in St. Johns Cathedral, s-Hertogenbosch and Xanten Cathedral. A bronze lectern for St. Peter's Church, Leuven is now in the collection of The Cloisters in New York. Peter Vischer of Nuremberg, and his sons, working on the bronze reliquary of Saint Sebald, a finely conceived monument of architectural form, with rich details of ornament and figures; among the latter appearing the artist in his working dress. The shrine was completed and set up in the year 1516. This great craftsman executed other fine works at Magdeburg, Römhild and Breslau. Reference should be made to the colossal monument at Innsbruck, the tomb of the Emperor Maximilian I, with its 28 bronze statues of more than life size. Large fountains in which bronze was freely employed were set up, such as those at Munich and Augsburg. The tendency was to use this metal for large works of an architectural or sculpturesque nature; while at the same time smaller objects were produced for domestic purposes. By the late 15th to 16th centuries, a style of ornamental brass bowls called Beckenschlägerschüssel had developed. | 1 | Applied and Interdisciplinary Chemistry |
Autothermal thermophilic aerobic digestion is a faecal sludge treatment design concept that uses the nutrients in the sludge and the metabolic heat of the bacteria to create high temperatures in the aerobic digester. This gradually shifts the microbial community towards thermophilic at temperatures typically at 55-degree Celsius or above. While the higher aeration requirements of autothermal thermophilic aerobic digestion further increases energy use and potential smell nuisance, the increased temperature makes the resulting biosolids much safer for re-use. | 1 | Applied and Interdisciplinary Chemistry |
In 1946 or 1947, Weeks began collaborating with Charles A. Browne on a retrospective history of the American Chemical Society. Browne was responsible for the structure of the project and the first nine chapters. After Brownes death in 1947, Weeks brought the project to completion, and A History of the American Chemical Society—Seventy-five Eventful Years' was published in 1952. It was welcomed as avoiding the pitfalls common to commissioned histories. | 1 | Applied and Interdisciplinary Chemistry |
Medical devices are classified by the US Food and Drug Administration (FDA) under three different classes depending on the risks the medical device may impose on the user. According to 21CFR 860.3, Class I devices are considered to pose the least amount of risk to the user and require the least amount of control. Class I devices include simple devices such as arm slings and hand-held surgical instruments. Class II devices are considered to need more regulation than Class I devices and are required to undergo specific requirements before FDA approval. Class II devices include X-ray systems and physiological monitors. Class III devices require the most regulatory controls since the device supports or sustains human life or may not be well tested. Class III devices include replacement heart valves and implanted cerebellar stimulators. Many implants typically fall under Class II and Class III devices. | 1 | Applied and Interdisciplinary Chemistry |
Compounds where phosphorus exists in a formal oxidation state of less than III are uncommon, but examples are known for each class. Organophosphorus(0) species are debatably illustrated by the carbene adducts, [P(NHC)], where NHC is an N-heterocyclic carbene. With the formulae (RP) and (RP), respectively, compounds of phosphorus(I) and (II) are generated by reduction of the related organophosphorus(III) chlorides:
:5 PhPCl + 5 Mg → (PhP) + 5 MgCl
:2 PhPCl + Mg → PhP-PPh + MgCl
Diphosphenes, with the formula RP, formally contain phosphorus-phosphorus double bonds. These phosphorus(I) species are rare but are stable provided that the organic substituents are large enough to prevent catenation. Many mixed-valence compounds are known, e.g. the cage P(CH). | 0 | Theoretical and Fundamental Chemistry |
Panel edge staining is a naturally occurring problem that occurs to anodized aluminium and stainless steel panelling and façades. It is semi-permanent staining that dulls the panel or façade's surface (in particular the edges of the panelling), reducing the natural lustre and shine produced by the anodizing processes used on the aluminium. Panel edge staining may also appear on powder coated aluminium, painted aluminium, stainless steel and titanium surfaces. | 1 | Applied and Interdisciplinary Chemistry |
Animal based approaches to phenotypic screening are not as amenable to screening libraries containing thousands of small molecules. Therefore, these approaches have found more utility in evaluating already approved drugs or late stage drug candidates for drug repositioning.
A number of companies including Melior Discovery, Phylonix, and Sosei have specialized in using phenotypic screening in animal disease models for drug positioning. Many other companies are involved in phenotypic screening research approaches, including Eurofins Discovery Phenotypic Services, Evotec, Dharmacon, Inc., ThermoScientific, Cellecta, and Persomics. | 1 | Applied and Interdisciplinary Chemistry |
Jeewanu (Sanskrit for "particles of life") are synthetic chemical particles that possess cell-like structure and seem to have some functional properties; that is, they are a model of primitive cells, or protocells. It was first synthesised by Krishna Bahadur (20 January 1926 — 5 August 1994), an Indian chemist and his team in 1963. Using photochemical reaction, they produced coacervates, microscopic cell-like spheres from a mixture of simple organic and inorganic compounds. Bahadur named these particles Jeewanu because they exhibit some of the basic properties of a cell, such as the presence of semipermeable membrane, amino acids, phospholipids and carbohydrates. Further, like living cells, they had several catalytic activities. Jeewanu are cited as models of protocells for the origin of life, and as artificial cells. | 0 | Theoretical and Fundamental Chemistry |
Apparatus and technological support of the method is constantly developed. An NMR relaxometer is a device for relaxation time measuring. Laboratory NMR relaxometers for NMR signal registration are available in small sizes.
In NMR relaxometry (NMRR) only one specific NMRR parameter is measured, not the whole spectrum (which is not always needed). This helps to save time and resources and makes it possible to use an NMR relaxometer as a portable express analyzer in different branches of industry, science and technology, environmental protection, etc. | 0 | Theoretical and Fundamental Chemistry |
The term "topochemistry" was first introduced by Kohlschütter in 1919, referring to the chemical reactions driven by the molecular alignments within the crystal. The prefix "topo" came from the Greek word "topos", which means "site". These reactions quickly draw people's attention because of their high conversion as well as solvent/catalyst-free nature. However, the early studies were usually serendipitous.
In the 1960s, Schmidts work on [2+2] photodimerization of cinnamic acids established the systematic approach to study the topochemical reactions. They proposed that only double bonds adopting coplanar and parallel orientation within a distance of 3.5-4.2 Å could react with each other in the crystal lattice. This empirical rule was later referred to as Schmidts criteria.
[2+2] cycle addition and diacetylene polymerization are among the early examples of topochemical polymerization. As shown in the figure, the formation of 1,3-diphenyl substituted cyclobutane derivatives was first studied in detail by Hasegawa and his coworkers in 1967. A series of similar monomers had also been studied by them. In 1969, the 1,4-addition polymerization of diacetylene was confirmed by Wegner and his coworkers. Restricted by the experimental condition, early researchers of topochemical polymerization usually characterized the reaction process and product with traditional chemical methods. The development of modern analysis technology such as single-crystal X-ray diffraction greatly facilitated the systematic study of topochemical polymerization and kept the popularity till these days. | 0 | Theoretical and Fundamental Chemistry |
Cycloisomerization is any isomerization in which the cyclic isomer of the substrate is produced in the reaction coordinate. The greatest advantage of cycloisomerization reactions is its atom economical nature, by design nothing is wasted, as every atom in the starting material is present in the product. In most cases these reactions are mediated by a transition metal catalyst, in few cases organocatalysts and rarely do they occur under thermal conditions. These cyclizations are able to be performed with excellent levels of selectivity in numerous cases and have transformed cycloisomerization into a powerful tool for unique and complex molecular construction. Cycloisomerization is a very broad topic in organic synthesis and many reactions that would be categorized as such exist. Two basic classes of these reactions are intramolecular Michael addition and Intramolecular Diels–Alder reactions. Under the umbrella of cycloisomerization, enyne and related olefin cycloisomerizations are the most widely used and studied reactions. | 0 | Theoretical and Fundamental Chemistry |
The first paper describing TILLING used HPLC to identify mutations (McCallum et al., 2000a). The method was made more high throughput by using the restriction enzyme Cel-I combined with the LICOR gel based system to identify mutations (Colbert et al.,2001). Advantages to using this system are that mutation sites can be easily confirmed and differentiated from noise. This is because different colored dyes can be used for the forward and reverse primers. Once the cleavage products have been run on a gel, it can be viewed in separate channels, and much like an RFLP, the fragment sizes within a lane in each channel should add up to the full length product size. Advantages to the LICOR system are separation of large fragments (~ 2kb), high sample throughput (96 samples loaded on paper combs), and freeware to identify the mutations (GelBuddy). Drawbacks to the LICOR system is having to pour slab gels and long run times (~4 hours). TILLING and EcoTILLING methods are now being used on capillary systems from, Advanced Analytical Technologies, ABI and Beckman.
Several systems can be used to separate PCR products that are not labeled with dyes. Simple agarose electrophoresis systems will separate cleavage products inexpensively and with standard lab equipment. This was used to discover SNPs in chum salmon and was referred to as DEcoTILLING. The disadvantage of this system is reduced resolution compared to polyacrylamide systems. Elchrom Scientific sells Spreadex gels which are precast, can be high throughput and are more sensitive than standard polyacrylamide gels. Advanced Analytical Technologies Inc sells the AdvanCE FS96 dsDNA Fluorescent System which is a 96 capillary electrophoresis system that has several advantages over traditional methods; including ability to separate large fragments (up to 40kb), no desalting or precipitation step required, short run times (~30 minutes), sensitivity to 5pg/ul and no need for fluorescent labeled primers. | 1 | Applied and Interdisciplinary Chemistry |
Sulfur tetrafluoride is the premier example of a molecule with the disphenoidal molecular geometry (see image at upper right). The following compounds and ions have disphenoidal geometry:
*SF
*SeF
*IOF
*TeF
*XeOF
*SCl | 0 | Theoretical and Fundamental Chemistry |
The restriction modification system (RM system) is found in bacteria and other prokaryotic organisms, and provides a defense against foreign DNA, such as that borne by bacteriophages.
Bacteria have restriction enzymes, also called restriction endonucleases, which cleave double-stranded DNA at specific points into fragments, which are then degraded further by other endonucleases. This prevents infection by effectively destroying the foreign DNA introduced by an infectious agent (such as a bacteriophage). Approximately one-quarter of known bacteria possess RM systems and of those about one-half have more than one type of system.
As the sequences recognized by the restriction enzymes are very short, the bacterium itself will almost certainly contain some within its genome. In order to prevent destruction of its own DNA by the restriction enzymes, methyl groups are added. These modifications must not interfere with the DNA base-pairing, and therefore, usually only a few specific bases are modified on each strand.
Endonucleases cleave internal/non-terminal phosphodiester bonds. They do so only after recognising specific sequences in DNA which are usually 4–6 base pairs long, and often palindromic. | 1 | Applied and Interdisciplinary Chemistry |
Many synthetic molecular knots have a distinct globular shape and dimensions that make them potential building blocks in nanotechnology. | 0 | Theoretical and Fundamental Chemistry |
A heated probe tip version of Dip Pen Lithography has also been demonstrated, thermal Dip Pen Lithography (tDPL), to deposit nanoparticles. Semiconductor, magnetic, metallic, or optically active nanoparticles can be written to a substrate via this method. The particles are suspended in a Poly(methyl methacrylate) (PMMA) or equivalent polymer matrix, and heated by the probe tip until they begin to flow. The probe tip acts as a nano-pen, and can pattern nanoparticles into a programmed structure. Depending on the size of the nanoparticles, resolutions of 78–400 nm were attained. An O plasma etch can be used to remove the PMMA matrix, and in the case of Iron Oxide nanoparticles, further reduce the resolution of lines to 10 nm. Advantages unique to tDPL are that it is a maskless additive process that can achieve very narrow resolutions, it can also easily write many types of nanoparticles without requiring special solution preparation techniques. However there are limitations to this method. The nanoparticles must be smaller than the radius of gyration of the polymer, in the case of PMMA this is about 6 nm. Additionally, as nanoparticles increase in size viscosity increases, slowing the process. For a pure polymer deposition speeds of 200 μm/s are achievable. Adding nanoparticles reduces speeds to 2 μm/s, but is still faster than regular Dip Pen Lithography. | 1 | Applied and Interdisciplinary Chemistry |
Scientists associated with the initial development of recombinant DNA methods recognized that the potential existed for organisms containing recombinant DNA to have undesirable or dangerous properties. At the 1975 Asilomar Conference on Recombinant DNA, these concerns were discussed and a voluntary moratorium on recombinant DNA research was initiated for experiments that were considered particularly risky. This moratorium was widely observed until the National Institutes of Health (USA) developed and issued formal guidelines for rDNA work. Today, recombinant DNA molecules and recombinant proteins are usually not regarded as dangerous. However, concerns remain about some organisms that express recombinant DNA, particularly when they leave the laboratory and are introduced into the environment or food chain. These concerns are discussed in the articles on genetically modified organisms and genetically modified food controversies. Furthermore, there are concerns about the by-products in biopharmaceutical production, where recombinant DNA result in specific protein products. The major by-product, termed host cell protein, comes from the host expression system and poses a threat to the patient's health and the overall environment. | 1 | Applied and Interdisciplinary Chemistry |
S-Adenosylmethioninamine is a substrate that is required for the biosynthesis of polyamines including spermidine, spermine, and thermospermine. It is produced by decarboxylation of S-adenosyl methionine. | 1 | Applied and Interdisciplinary Chemistry |
Repeat Associated Non-AUG translation, or RAN translation, is an irregular mode of mRNA translation that can occur in eukaryotic cells. | 1 | Applied and Interdisciplinary Chemistry |
Biologists have not always viewed the Müllerian mechanism as mimicry, both because the term was strongly associated with Batesian mimicry, and because no deceit was involved—unlike the situation in Batesian mimicry, the aposematic signals given by Müllerian mimics are (unconsciously) honest. Earlier terms, no longer in use, for Müllerian mimicry included "homotypy", "nondeceitful homotypy" and "arithmetic homotypy". | 1 | Applied and Interdisciplinary Chemistry |
Z-Cote was acquired from SunSmart in 1999 by BASF. It has been used in sunscreen formulations since at least 1993 in microfine form. The initial 1991 Z-Cote patent placed emphasis on broad-spectrum protection, especially UVA. Only in 1993 did the FDA approve an alternative petrochemical sunscreen ingredient, avobenzone, that also provided protection against UVA. | 1 | Applied and Interdisciplinary Chemistry |
The Green Revolution of the 1960s and 70s introduced sturdier plants that could support the heavier grain loads resulting from intensive fertilizer use. Pesticide imports by 11 Southeast Asian countries grew nearly sevenfold in value between 1990 and 2010, according to FAO statistics, with disastrous results. Rice farmers become accustomed to spraying soon after planting, triggered by signs of the leaf folder moth, which appears early in the growing season. It causes only superficial damage and doesnt reduce yields. In 1986, Indonesia banned 57 pesticides and completely stopped subsidizing their use. Progress was reversed in the 2000s, when growing production capacity, particularly in China, reduced prices. Rice production in Asia more than doubled. But it left farmers believing more is better—whether it's seed, fertilizer, or pesticides.
The brown planthopper, Nilaparvata lugens, the farmers' main target, has become increasingly resistant. Since 2008, outbreaks have devastated rice harvests throughout Asia, but not in the Mekong Delta. Reduced spraying allowed natural predators to neutralize planthoppers in Vietnam. In 2010 and 2011, massive planthopper outbreaks hit 400,000 hectares of Thai rice fields, causing losses of about $64 million. The Thai government is now pushing the "no spray in the first 40 days" approach.
By contrast early spraying kills frogs, spiders, wasps and dragonflies that prey on the later-arriving and dangerous planthopper and produced resistant strains. Planthoppers now require pesticide doses 500 times greater than originally. Overuse indiscriminately kills beneficial insects and decimates bird and amphibian populations. Pesticides are suspected of harming human health and became a common means for rural Asians to commit suicide.
In 2001, scientists challenged 950 Vietnamese farmers to try IPM. In one plot, each farmer grew rice using their usual amounts of seed and fertilizer, applying pesticide as they chose. In a nearby plot, less seed and fertilizer were used and no pesticides were applied for 40 days after planting. Yields from the experimental plots was as good or better and costs were lower, generating 8% to 10% more net income. The experiment led to the "three reductions, three gains" campaign, claiming that cutting the use of seed, fertilizer and pesticide would boost yield, quality and income. Posters, leaflets, TV commercials and a 2004 radio soap opera that featured a rice farmer who gradually accepted the changes. It didnt hurt that a 2006 planthopper outbreak hit farmers using insecticides harder than those who didnt. Mekong Delta farmers cut insecticide spraying from five times per crop cycle to zero to one.
The Plant Protection Center and the International Rice Research Institute (IRRI) have been encouraging farmers to grow flowers, okra and beans on rice paddy banks, instead of stripping vegetation, as was typical. The plants attract bees and a tiny wasp that eats planthopper eggs, while the vegetables diversify farm incomes.
Agriculture companies offer bundles of pesticides with seeds and fertilizer, with incentives for volume purchases. A proposed law in Vietnam requires licensing pesticide dealers and government approval of advertisements to prevent exaggerated claims. Insecticides that target other pests, such as Scirpophaga incertulas (stem borer), the larvae of moth species that feed on rice plants allegedly yield gains of 21% with proper use. | 0 | Theoretical and Fundamental Chemistry |
For some polyprotic acids, dissociation (or association) occurs at more than one nonequivalent site, and the observed macroscopic equilibrium constant, or macro-constant, is a combination of micro-constants involving distinct species. When one reactant forms two products in parallel, the macro-constant is a sum of two micro-constants, This is true for example for the deprotonation of the amino acid cysteine, which exists in solution as a neutral zwitterion . The two micro-constants represent deprotonation either at sulphur or at nitrogen, and the macro-constant sum here is the acid dissociation constant
Similarly, a base such as spermine has more than one site where protonation can occur. For example, mono-protonation can occur at a terminal group or at internal groups. The K values for dissociation of spermine protonated at one or other of the sites are examples of micro-constants. They cannot be determined directly by means of pH, absorbance, fluorescence or NMR measurements; a measured K value is the sum of the K values for the micro-reactions.
Nevertheless, the site of protonation is very important for biological function, so mathematical methods have been developed for the determination of micro-constants.
When two reactants form a single product in parallel, the macro-constant For example, the abovementioned equilibrium for spermine may be considered in terms of K values of two tautomeric conjugate acids, with macro-constant In this case This is equivalent to the preceding expression since is proportional to
When a reactant undergoes two reactions in series, the macro-constant for the combined reaction is the product of the micro-constant for the two steps. For example, the abovementioned cysteine zwitterion can lose two protons, one from sulphur and one from nitrogen, and the overall macro-constant for losing two protons is the product of two dissociation constants This can also be written in terms of logarithmic constants as | 0 | Theoretical and Fundamental Chemistry |
Acidic polysaccharides are polysaccharides that contain carboxyl groups, phosphate groups and/or sulfuric ester groups.
Polysaccharides containing sulfate groups can be isolated from algae or obtained by chemical modification.
Polysaccharides are major classes of biomolecules. They are long chains of carbohydrate molecules, composed of several smaller monosaccharides. These complex bio-macromolecules functions as an important source of energy in animal cell and form a structural component of a plant cell. It can be a homopolysaccharide or a heteropolysaccharide depending upon the type of the monosaccharides.
Polysaccharides can be a straight chain of monosaccharides known as linear polysaccharides, or it can be branched known as a branched polysaccharide. | 0 | Theoretical and Fundamental Chemistry |
For defensive purposes, navies use arrays of magnetometers laid across sea floors in strategic locations (i.e. around ports) to monitor submarine activity. The Russian Alfa-class titanium submarines were designed and built at great expense to thwart such systems (as pure titanium is non-magnetic).
Military submarines are degaussed—by passing through large underwater loops at regular intervals—to help them escape detection by sea-floor monitoring systems, magnetic anomaly detectors, and magnetically-triggered mines. However, submarines are never completely de-magnetised. It is possible to tell the depth at which a submarine has been by measuring its magnetic field, which is distorted as the pressure distorts the hull and hence the field. Heating can also change the magnetization of steel.
Submarines tow long sonar arrays to detect ships, and can even recognise different propeller noises. The sonar arrays need to be accurately positioned so they can triangulate direction to targets (e.g. ships). The arrays do not tow in a straight line, so fluxgate magnetometers are used to orient each sonar node in the array.
Fluxgates can also be used in weapons navigation systems, but have been largely superseded by GPS and ring laser gyroscopes.
Magnetometers such as the German Foerster are used to locate ferrous ordnance. Caesium and Overhauser magnetometers are used to locate and help clean up old bombing and test ranges.
UAV payloads also include magnetometers for a range of defensive and offensive tasks. | 0 | Theoretical and Fundamental Chemistry |
The charge transfer coefficient signifies the fraction of the interfacial potential at an electrode-electrolyte interface that helps in lowering the free energy barrier for the electrochemical reaction. The electroactive ion present in the interfacial region experiences the interfacial potential and electrostatic work is done on the ion by a part of the interfacial electric field. It is charge transfer coefficient that signifies this part that is utilized in activating the ion to the top of the free energy barrier. | 0 | Theoretical and Fundamental Chemistry |
Among different possibilities to measure the effect on the magnet system, it has been successfully applied those based on the measurement of the deflection of a parallel spring under an applied force. Firstly using a strain gauge and then recording the deflection of a quartz spring with an interferometer, in whose case the deformation is detected to within 0.1 nm. | 1 | Applied and Interdisciplinary Chemistry |
CMF has been tested against larger-caliber armour-piercing rounds. S-S CMF panels were manufactured and paired with a ceramic faceplate and aluminium backplate. The layered hard armours were tested against .50 BMG ball and AP rounds at a range of impact velocities. The mild steel cores of the ball rounds penetrated one of the three samples but revealed the benefits of using multiple tiles over a single ceramic faceplate to limit the spread of damage. The hardened steel core of the AP rounds penetrated deep into the ceramic faceplate, compressing the CMF layer until the projectile was either stopped and embedded within the armour or was able to fully penetrate and exit the backing plate. The experimental results were compared to commercially available armour materials and offer improved performance with reduced weight. The CMF layer is estimated to absorb between 69 and 79% of the bullet's kinetic energy, in their unoptimized testing condition. At impact velocities above 800 m/s, the CMF layer consistently absorbed up to 79% of the impact energy. As the impact velocity increased, so did the effective strength of the CMF layer due to the strain rate sensitivity of the material. The mass efficiency ratio of the armours, when compared to rolled homogeneous armour (RHA), was calculated to be 2.1. The CMF hard armours can effectively stop an incoming round at less than half the weight of the required RHA. The weight savings afforded by using such novel armour can improve the fuel efficiency of military vehicles without sacrificing the protection of the personnel or the equipment inside. | 0 | Theoretical and Fundamental Chemistry |
GUIDE-Seq has been shown to miss some off-targets, when compared to the genome-wide sequencing DIGENOME-Seq method, due to the nature of its targeting. Another caveat is that GUIDE-Seq has been observed to generate slightly different off-target sites depending on the cell line. This could be due to cell lines having different parental genetic origins, cell line specific mutations, or, in the case of some immortal cell lines such as K562s, having aneuploidy. This suggests that it would be pertinent for researchers to test multiple cell lines to validate efficacy and accuracy. GUIDE-Seq cannot be used to identify off-targets in vivo. | 1 | Applied and Interdisciplinary Chemistry |
Palladacycles are used as pre-catalysts, usually by the reductive elimination from palladium(II) to the catalytically active palladium(0). In the example of 2-aminobiphenyl palladacycles, a kinetically active 12-electrons Pd(0) species is formed, allowing for further oxidative addition with reactants. A series of 2-aminobiphenyl bearing various X and L groups were synthesized to better understand the electron/steric effect.
By employing palladacycles as pre-catalysts, high reactivity and selectivity have been achieved in Heck reaction[2] and a variety of cross-coupling reactions, such as Suzuki, Sonogashira, Stille, Buchwald–Hartwig reactions.
Total synthesis containing palladacycles have been demonstrated. | 0 | Theoretical and Fundamental Chemistry |
In 1958, the Central Public Health Engineering Research Institute (CPHERI) was established. It was created by the Council of Scientific and Industrial Research (CSIR). In 1974, after participating in the "United Nations Inter-Governmental Conference on Human Environment" and with its renaming by Prime Minister Indira Gandhi, CPHERI became the National Environmental Engineering Research Institute (NEERI). NEERI has headquarters in Nagpur and five zonal laboratories in Mumbai, Kolkata, Delhi, Chennai, and Hyderabad.
The study for the location of a new municipal solid waste landfill site in Kolkata used the institute's 2005 guidelines.
During the COVID-19 crisis, the institute developed a saline gargling sample method to trace the disease. | 1 | Applied and Interdisciplinary Chemistry |
Iron is stored as iron(III) in ferritin. The exact nature of the binding site has not yet been determined. The iron appears to be present as a hydrolysis product such as FeO(OH). Iron is transported by transferrin whose binding site consists of two tyrosines, one aspartic acid and one histidine. The human body has no mechanism for iron excretion. This can lead to iron overload problems in patients treated with blood transfusions, as, for instance, with β-thalassemia. Iron is actually excreted in urine and is also concentrated in bile which is excreted in feces. | 1 | Applied and Interdisciplinary Chemistry |
In biochemistry, a rate-limiting step is a step that controls the rate of a series of biochemical reactions. The statement is, however, a misunderstanding of how a sequence of enzyme catalyzed reaction steps operate. Rather than a single step controlling the rate, it has been discovered that multiple steps control the rate. Moreover, each controlling step controls the rate to varying degrees.
Blackman (1905) stated as an axiom: "when a process is conditioned as to its rapidity by a number of separate factors, the rate of the process is limited by the pace of the slowest factor." This implies that it should be possible, by studying the behavior of a complicated system such as a metabolic pathway, to characterize a single factor or reaction (namely the slowest), which plays the role of a master or rate-limiting step. In other words, the study of flux control can be simplified to the study of a single enzyme since, by definition, there can only be one rate-limiting step. Since its conception, the rate-limiting step has played a significant role in suggesting how metabolic pathways are controlled. Unfortunately, the notion of a rate-limiting step is erroneous, at least under steady-state conditions. Modern biochemistry textbooks have begun to play down the concept. For example, the seventh edition of Lehninger Principles of Biochemistry explicitly states: "It has now become clear that, in most pathways, the control of flux is distributed among several enzymes, and the extent to which each contributes to the control varies with metabolic circumstances". However, the concept is still incorrectly used in research articles. | 1 | Applied and Interdisciplinary Chemistry |
Skunk is a malodorant, non-lethal weapon used for crowd control by the Israel Defense Forces (IDF) and marketed to militaries and law enforcement around the world. It was developed and is manufactured by Odortec, with two supporting companies, Man and Beit-Alfa Technologies. The liquid's strong odor is marketed as an improvement over other crowd control weapons (CCWs) such as rubber bullets and tear gas used by the IDF against Palestinian protestors. The IDF is criticized for its tactics during deployment, including common use against people, businesses, and neighborhoods not involved in protests as a form of collective punishment. | 1 | Applied and Interdisciplinary Chemistry |
Oceanic anoxic events have had many important consequences. It is believed that they have been responsible for mass extinctions of marine organisms both in the Paleozoic and Mesozoic. The early Toarcian and Cenomanian-Turonian anoxic events correlate with the Toarcian and Cenomanian-Turonian extinction events of mostly marine life forms. Apart from possible atmospheric effects, many deeper-dwelling marine organisms could not adapt to an ocean where oxygen penetrated only the surface layers.
An economically significant consequence of oceanic anoxic events is the fact that the prevailing conditions in so many Mesozoic oceans has helped produce most of the world's petroleum and natural gas reserves. During an oceanic anoxic event, the accumulation and preservation of organic matter was much greater than normal, allowing the generation of potential petroleum source rocks in many environments across the globe. Consequently, some 70 percent of oil source rocks are Mesozoic in age, and another 15 percent date from the warm Paleogene: only rarely in colder periods were conditions favorable for the production of source rocks on anything other than a local scale. | 0 | Theoretical and Fundamental Chemistry |
In 2008, Alpert coined the term, ERLIC (electrostatic repulsion hydrophilic interaction chromatography), for HILIC separations where an ionic column surface chemistry is used to repel a common ionic polar group on an analyte or within a set of analytes, to facilitate separation by the remaining polar groups. Electrostatic effects have an order of magnitude stronger chemical potential than neutral polar effects. This allows one to minimize the influence of a common, ionic group within a set of analyte molecules; or to reduce the degree of retention from these more polar functional groups, even enabling isocratic separations in lieu of a gradient in some situations. His subsequent publication further described orientation effects which others have also called ion-pair normal phase or e-HILIC, reflecting retention mechanisms sensitive to a particular ionic portion of the analyte, either attractive or repulsive. ERLIC (eHILIC) separations need not be isocratic, but the net effect is the reduction of the attraction of a particularly strong polar group, which then requires less strong elution conditions, and the enhanced interaction of the remaining polar (opposite charged ionic, or non-ionic) functional groups of the analyte(s).Based on the ERLIC column invented by Andrew Alpert, a new peptide mapping methodology was developed with unique properties of separation of asparagine deamidation and isomerization. This unique properties would be very beneficial for future mass spectrometry based multi-attributes monitoring in biologics quality control. | 1 | Applied and Interdisciplinary Chemistry |
Now consider the case of a chain of two decays: one nuclide decaying into another by one process, then decaying into another by a second process, i.e. . The previous equation cannot be applied to the decay chain, but can be generalized as follows. Since decays into , then decays into , the activity of adds to the total number of nuclides in the present sample, before those nuclides decay and reduce the number of nuclides leading to the later sample. In other words, the number of second generation nuclei increases as a result of the first generation nuclei decay of , and decreases as a result of its own decay into the third generation nuclei . The sum of these two terms gives the law for a decay chain for two nuclides:
The rate of change of , that is , is related to the changes in the amounts of and , can increase as is produced from and decrease as produces .
Re-writing using the previous results:
The subscripts simply refer to the respective nuclides, i.e. is the number of nuclides of type ; is the initial number of nuclides of type ; is the decay constant for – and similarly for nuclide . Solving this equation for gives:
In the case where is a stable nuclide ( = 0), this equation reduces to the previous solution:
as shown above for one decay. The solution can be found by the integration factor method, where the integrating factor is . This case is perhaps the most useful since it can derive both the one-decay equation (above) and the equation for multi-decay chains (below) more directly. | 0 | Theoretical and Fundamental Chemistry |
* The oxidative addition of MeI to Ir(I) complexes was shown to proceed about 100 times faster with a hemilabile phosphane ligand compared to a very similar non-labile ligand.
* Hydrovinylation (olefin dimerisation), which is typically difficult to carry out enantioselectively, has been shown to proceed with high enantiomeric excess when using a chiral phosphine ligand with an appropriately placed hemilabile coordinating group. The Pauson–Khand reaction, which is conceptually similar, has also been shown to give improved results when hemilabile P,S type hybrid ligands were used.
* Iridium(I) complexes incorporating hemilabile ligands which contain methoxy, dimethylamino, and pyridine as donor functions have been shown to be effective catalysts for transfer hydrogenation. | 0 | Theoretical and Fundamental Chemistry |
Sponge iron is not useful by itself, but can be processed to create wrought iron or steel. The sponge is removed from the furnace, called a bloomery, and repeatedly beaten with heavy hammers and folded over to remove the slag, oxidize any carbon or carbide, and weld the iron together. This treatment usually creates wrought iron with about three percent slag and a fraction of a percent of other impurities. Further treatment may add controlled amounts of carbon, allowing various kinds of heat treatment (e.g. "steeling").
Today, sponge iron is created by reducing iron ore without melting it. This makes for an energy-efficient feedstock for specialty steel manufacturers which used to rely upon scrap metal. | 1 | Applied and Interdisciplinary Chemistry |
In 2002 he received the State Prize of the Russian Federation in the field of science and technology. In 2011 he was awarded the Prize of the Government of the Russian Federation in the field of science and technology. He also received the Orders of the Red Banner of Labour (1986), Honour (1999) and Friendship (2009).
The Royal Society of Chemistry awarded Moiseev the Centenary Prize for 2006/7. In 2012, he was awarded the Demidov Prize for his contribution to the chemistry of organoelement compounds, petrochemistry, and carbene chemistry, and the RAS Chugaev Prize for his work on coordination compounds in industrially important redox reactions. In 2013 he received the RAS Mendeleev Medal for outstanding work in the field of catalysis and energy-saving technologies.
He became a corresponding member of the Academy of Sciences of the Soviet Union in 1990, and an academician of the Russian Academy of Sciences in 1992. He was a full member of the Academy of Sciences, Arts and Literature in Paris, the European Academy of Sciences and Arts, and the Academia Europaea. | 0 | Theoretical and Fundamental Chemistry |
The surface advances by the lateral motion of steps which are one interplanar spacing in height (or some integral multiple thereof). An element of surface undergoes no change and does not advance normal to itself except during the passage of a step, and then it advances by the step height. It is useful to consider the step as the transition between two adjacent regions of a surface which are parallel to each other and thus identical in configuration—displaced from each other by an integral number of lattice planes. Note here the distinct possibility of a step in a diffuse surface, even though the step height would be much smaller than the thickness of the diffuse surface. | 0 | Theoretical and Fundamental Chemistry |
Non-specific binding of primers frequently occurs and may occur for several reasons. These include repeat sequences in the DNA template, non-specific binding between primer and template, high or low G-C content in the template, or incomplete primer binding, leaving the 5' end of the primer unattached to the template. Non-specific binding of degenerate primers is also common. Manipulation of annealing temperature and magnesium ion concentration may be used to increase specificity. For example, lower concentrations of magnesium or other cations may prevent non-specific primer interactions, thus enabling successful PCR. A "hot-start" polymerase enzyme whose activity is blocked unless it is heated to high temperature (e.g., 90–98˚C) during the denaturation step of the first cycle, is commonly used to prevent non-specific priming during reaction preparation at lower temperatures. Chemically mediated hot-start PCRs require higher temperatures and longer incubation times for polymerase activation, compared with antibody or aptamer-based hot-start PCRs.
Other methods to increase specificity include Nested PCR and Touchdown PCR.
Computer simulations of theoretical PCR results (Electronic PCR) may be performed to assist in primer design.
Touchdown polymerase chain reaction or touchdown style polymerase chain reaction is a method of polymerase chain reaction by which primers will avoid amplifying nonspecific sequences. The annealing temperature during a polymerase chain reaction determines the specificity of primer annealing. The melting point of the primer sets the upper limit on annealing temperature. At temperatures just below this point, only very specific base pairing between the primer and the template will occur. At lower temperatures, the primers bind less specifically. Nonspecific primer binding obscures polymerase chain reaction results, as the nonspecific sequences to which primers anneal in early steps of amplification will "swamp out" any specific sequences because of the exponential nature of polymerase amplification.
The earliest steps of a touchdown polymerase chain reaction cycle have high annealing temperatures. The annealing temperature is decreased in increments for every subsequent set of cycles (the number of individual cycles and increments of temperature decrease is chosen by the experimenter). The primer will anneal at the highest temperature which is least-permissive of nonspecific binding that it is able to tolerate. Thus, the first sequence amplified is the one between the regions of greatest primer specificity; it is most likely that this is the sequence of interest. These fragments will be further amplified during subsequent rounds at lower temperatures, and will out compete the nonspecific sequences to which the primers may bind at those lower temperatures. If the primer initially (during the higher-temperature phases) binds to the sequence of interest, subsequent rounds of polymerase chain reaction can be performed upon the product to further amplify those fragments. | 1 | Applied and Interdisciplinary Chemistry |
Ferrosilicon is used as a source of silicon to reduce metals from their oxides and to deoxidize steel and other ferrous alloys. This prevents the loss of carbon from the molten steel (so called blocking the heat); ferromanganese, spiegeleisen, calcium silicides, and many other materials are used for the same purpose. It can be used to make other ferroalloys. Ferrosilicon is also used for manufacture of silicon, corrosion-resistant and high-temperature-resistant ferrous silicon alloys, and silicon steel for electromotors and transformer cores. In the manufacture of cast iron, ferrosilicon is used for inoculation of the iron to accelerate graphitization. In arc welding, ferrosilicon can be found in some electrode coatings.
Ferrosilicon is a basis for manufacture of prealloys like magnesium ferrosilicon (MgFeSi), used for production of ductile iron. MgFeSi contains 3–42% magnesium and small amounts of rare-earth metals. Ferrosilicon is also important as an additive to cast irons for controlling the initial content of silicon.
Magnesium ferrosilicon is instrumental in the formation of nodules, which give ductile iron its flexible property. Unlike gray cast iron, which forms graphite flakes, ductile iron contains graphite nodules, or pores, which make cracking more difficult.
Ferrosilicon is also used in the Pidgeon process to make magnesium from dolomite. | 1 | Applied and Interdisciplinary Chemistry |
Walter Cox McCrone Jr. (June 9, 1916July 10, 2002) was an American chemist who worked extensively on applications of polarized light microscopy and is sometimes characterized as the "father of modern microscopy". He was also an expert in electron microscopy, crystallography, ultra-microanalysis, and particle identification. In 1960 he founded the McCrone Research Institute, a non-profit educational and research organization for microscopy based in Chicago.
McCrones crystallographic work on polymorphism and its pharmaceutical applications played a central role in the subsequent development of the field. To the general public, McCrone was best known for his work in forensic science, especially his analyses of the Vinland Map and the Shroud of Turin. In 2000 he received the American Chemical Societys National Award in Analytical Chemistry. | 0 | Theoretical and Fundamental Chemistry |
* Avian myotubes: highly contractile skeletal myotubes cultured and differentiated in vitro on collagen-coated culture plates
* Cultured Meat (CM): cultured, cell based, lab grown, in vitro, clean meat obtained through cellular agriculture
* Human Bio-Artificial Muscle (BAM): formed through a seven day, in vitro tissue engineering procedure in which human myoblasts fuse and differentiate into aligned myofibres in an extracellular matrix; these constructs are used for intramuscular drug injection to replace pre- or non-clinical injection models and complement animal studies
* Myoblast transfer in the treatment of Duchenne's Muscular Dystrophy (DMD): an in vivo technique to replace dystrophin, a skeletal muscle protein which is deficient in patients with DMD; myoblasts fuse with muscle fibers and contribute their nuclei which then replace deficient gene products in the host nuclei
* Autologous hematopoetic stem cell transplantation (AHSCT) as a method for treating Multiple Sclerosis (MS): an in vivo technique for treating MS in which the immune system is destroyed and is reconstituted with hematopoetic stem cells; has been shown to reduce the effects of MS for 4-5 years in 70-80% of patients
* Volumetric muscle loss repair using Muscle Derived Stem Cells (MDSCs): an in situ technique for muscle loss repair in which patients have suffered from trauma or combat injuries; MDSCs cast in an in situ fibrin gel were capable of forming new myofibres that became engrafted in a muscle defect that was created by a partial-thickness wedge resection in the tibialis anterior muscle of laboratory mice
* Development of skeletal muscle organoids to model neuromuscular disorders and muscular dystrophies; an in vitro technique in which human pluripotent stem cells (hPSCs) are differentiated into functional 3D human skeletal muscle organoid (hSkMOs); hPSCs were guided towards the paraxial mesodermal lineage which then gives rise to myogenic pregenitor cells and myoblasts in well plates with no scaffold; organoids were round, uniformly sized, and exhibited homogeneous morphology upon full development and were shown to successfully model muscle development and regeneration
* Bioprinted Tibialis Anterior (TA) Muscle in Rats: an in vitro technique in which bioengineered skeletal muscle tissue composed of human primary muscle pregenitor cells (hMPCs) was fabricated – upon implantation, the bioprinted material reached 82% functional recovery in rodent models of the TA muscle | 1 | Applied and Interdisciplinary Chemistry |
A prefix di-, tri- etc. is added to the parent hydride name. Examples are:
*HOOH, dioxidane (hydrogen peroxide is an acceptable name)
*HPPH, diphosphane
*HSiSiHSiHSiH, tetrasilane | 0 | Theoretical and Fundamental Chemistry |
The Kastle–Meyer test is a presumptive blood test, first described in 1903, in which the chemical indicator phenolphthalein is used to detect the possible presence of hemoglobin. It relies on the peroxidase-like activity of hemoglobin in blood to catalyze the oxidation of phenolphthalin (the colorless reduced form of phenolphthalein) into phenolphthalein, which is visible as a bright pink color. The Kastle–Meyer test is a form of catalytic blood test, one of the two main classes of forensic tests commonly employed by crime labs in the chemical identification of blood. The other class of tests used for this purpose are microcrystal tests, such as the Teichmann crystal test and the Takayama crystal test.
The test was named after the American agricultural chemist, Joseph Hoeing Kastle (1864–1916), who in 1901, invented and tested the crude blood test, and the German physician and chemist, Erich Meyer (1874–1927), who modified the test in 1903. | 0 | Theoretical and Fundamental Chemistry |
Parts-per notation is often used describing dilute solutions in chemistry, for instance, the relative abundance of dissolved minerals or pollutants in water. The quantity "1 ppm" can be used for a mass fraction if a water-borne pollutant is present at one-millionth of a gram per gram of sample solution. When working with aqueous solutions, it is common to assume that the density of water is 1.00 g/mL. Therefore, it is common to equate 1 kilogram of water with 1 L of water. Consequently, 1 ppm corresponds to 1 mg/L and 1 ppb corresponds to 1 μg/L.
Similarly, parts-per notation is used also in physics and engineering to express the value of various proportional phenomena. For instance, a special metal alloy might expand 1.2 micrometers per meter of length for every degree Celsius and this would be expressed as Parts-per notation is also employed to denote the change, stability, or uncertainty in measurements. For instance, the accuracy of land-survey distance measurements when using a laser rangefinder might be 1 millimeter per kilometer of distance; this could be expressed as "Accuracy = 1 ppm."
Parts-per notations are all dimensionless quantities: in mathematical expressions, the units of measurement always cancel. In fractions like "2 nanometers per meter" so the quotients are pure-number coefficients with positive values less than or equal to 1. When parts-per notations, including the percent symbol (%), are used in regular prose (as opposed to mathematical expressions), they are still pure-number dimensionless quantities. However, they generally take the literal "parts per" meaning of a comparative ratio (e.g. "2 ppb" would generally be interpreted as "two parts in a billion parts").
Parts-per notations may be expressed in terms of any unit of the same measure. For instance, the expansion coefficient of some brass alloy, may be expressed as 18.7 (μm/m)/°C, or as 18.7 (μ in/in)/°C; the numeric value representing a relative proportion does not change with the adoption of a different unit of length.
Similarly, a metering pump that injects a trace chemical into the main process line at the proportional flow rate is doing so at a rate that may be expressed in a variety of volumetric units, including 125 cm/m, etc.
In nuclear magnetic resonance spectroscopy (NMR), chemical shift is usually expressed in ppm. It represents the difference of a measured frequency in parts per million from the reference frequency. The reference frequency depends on the instruments magnetic field and the element being measured. It is usually expressed in MHz. Typical chemical shifts are rarely more than a few hundred Hz from the reference frequency, so chemical shifts are conveniently expressed in ppm (Hz/MHz). Parts-per notation gives a dimensionless quantity that does not depend on the instruments field strength. | 1 | Applied and Interdisciplinary Chemistry |
The SH2 (Src Homology 2) domain is a structurally conserved protein domain contained within the Src oncoprotein and in many other intracellular signal-transducing proteins. SH2 domains bind to phosphorylated tyrosine residues on other proteins, modifying the function or activity of the SH2-containing protein. The SH2 domain may be considered the prototypical modular protein-protein interaction domain, allowing the transmission of signals controlling a variety of cellular functions. SH2 domains are especially common in adaptor proteins that aid in the signal transduction of receptor tyrosine kinase pathways. | 1 | Applied and Interdisciplinary Chemistry |
Jet aerators do not require any external air source (i.e. compressor), except for the surrounding atmosphere. Jet aerators can be installed either as submersible units or piped through the tank wall using an external dry-installed chopper pump to feed the aspirating ejector(s). Jet aerators are easily configured into any basin geometry including circular, rectangular, looped reactors and sloped wall basins. Jet aerators are ideally suited for deep tank processes. The jet oxidation ditch is an example of technology innovation where the combination of a deeper basin design, bottom to top mixing and conservation of momentum combines to make a very efficient treatment process. In this and other applications the independent control of oxygen transfer and mixing is a valuable feature for both process control and energy savings. | 1 | Applied and Interdisciplinary Chemistry |
"Hairs" on plants are properly called trichomes. Leaves can show several degrees of hairiness. The meaning of several of the following terms can overlap.
;Arachnoid, or arachnose: With many fine, entangled hairs giving a cobwebby appearance.
;Barbellate: With finely barbed hairs (barbellae).
;Bearded: With long, stiff hairs.
;Bristly: With stiff hair-like prickles.
;Canescent: Hoary with dense grayish-white pubescence.
;Ciliate: Marginally fringed with short hairs (cilia).
;Ciliolate: Minutely ciliate.
;Floccose: With flocks of soft, woolly hairs, which tend to rub off.
;Glabrescent: Losing hairs with age.
;Glabrous: No hairs of any kind present.
;Glandular: With a gland at the tip of the hair.
;Hirsute: With rather rough or stiff hairs.
;Hispid: With rigid, bristly hairs.
;Hispidulous: Minutely hispid.
;Hoary: With a fine, close grayish-white pubescence.
;Lanate, or lanose: With woolly hairs.
;Pilose: With soft, clearly separated hairs.
;Puberulent, or puberulous: With fine, minute hairs.
;Pubescent: With soft, short and erect hairs.
;Scabrous, or scabrid: Rough to the touch.
;Sericeous: Silky appearance through fine, straight and appressed (lying close and flat) hairs.
;Silky: With adpressed, soft and straight pubescence.
;Stellate, or stelliform: With star-shaped hairs.
;Strigose: With appressed, sharp, straight and stiff hairs.
;Tomentose: Densely pubescent with matted, soft white woolly hairs.
;Tomentulose: Minutely or only slightly tomentose.
;Villous: With long and soft hairs, usually curved.
;Woolly: With long, soft and tortuous or matted hairs. | 0 | Theoretical and Fundamental Chemistry |
In the medical field, experiments are done to test for the uses of cell-cell fusogens in axonal nerve repairs and to determine their usefulness with other nerve cells. The current method for nerve repair is suturing the cut ends of nerves. This has a long recovery process, with a low functionality rate for the repaired nerves. When considering cell-cell fusogens as a potential answer, researchers divided these fusogens into two groups based on fusion mechanisms: cell aggregation and membrane modification. One fusogen PEG was found to fit in both groups. It was this fusogen that made restoring nerve cells in humans possible. Once operations were within a certain time frame (12 hours for human nerve repair and 24 hours for sciatic rat treatments), patient recovery was almost successful. With this research, there is potential for repairing human nerve grafts. Some potential uses of cell-cell fusogens studied are cancer vaccines and the regeneration of damaged cells. Additionally, any peripheral nerve in the body could be repaired, and transferred tissues could work as soon as the senses return. Finally, any surgery done on nerves could be repaired as well, thus resulting in a quicker recovery. | 1 | Applied and Interdisciplinary Chemistry |
An interest in the natural world, combined with the logic of science and math, attracted Lynch-Stieglitz to science and after a summer at the Duke University Marine Laboratory she decided on a career in physical oceanography. In 1986, she earned B.S. degrees in physics and geology from Duke University and for two years she worked as an oceanographer at the Pacific Marine Environmental Laboratory. From 1988 until 1989 she worked at the Maryland Science Center and as a programmer at Johns Hopkins University before moving to Columbia University where she earned an M.A. (1991) and Ph.D. (1995) in geological sciences. After two years as a postdoctoral scholar at Woods Hole Oceanographic Institution, in 1996 she returned to New York where she joined the faculty of the Lamont–Doherty Earth Observatory. In 2004, Lynch-Stieglitz moved to the Georgia Institute of Technology where she was promoted to professor in 2010.
From 2012 to 2015, Lynch-Stieglitz was the Editor of Earth and Planetary Science Letters.
In 2015 Lynch-Stieglitz was elected a fellow of the American Association for the Advancement of Science "for bringing physical oceanography approaches to the study of transient circulation changes during ice ages, providing a window into the ocean’s interaction with today’s climate change." | 0 | Theoretical and Fundamental Chemistry |
In Fick's original method, the following variables are measured:
* V̇O, oxygen consumption in ml of pure gaseous oxygen per minute. This may be measured using a spirometer within a closed rebreathing circuit incorporating a CO absorber
* C, the oxygen content of blood taken from the pulmonary vein (representing oxygenated blood)
* C, the oxygen content of blood from an intravenous cannula (representing deoxygenated blood) | 1 | Applied and Interdisciplinary Chemistry |
Marine carbon is further separated into particulate and dissolved phases. These pools are operationally defined by physical separation – dissolved carbon passes through a 0.2 μm filter, and particulate carbon does not.
There are two main types of inorganic carbon that are found in the oceans:
* Dissolved inorganic carbon (DIC) is made up of bicarbonate (), carbonate () and carbon dioxide (including both dissolved CO and carbonic acid HCO). DIC can be converted to particulate inorganic carbon (PIC) through precipitation of CaCO (biologically or abiotically). DIC can also be converted to particulate organic carbon (POC) through photosynthesis and chemoautotrophy (primary production). DIC increases with depth as organic carbon particles sink and are respired. Free oxygen decreases as DIC increases because oxygen is consumed during aerobic respiration.
* Particulate inorganic carbon (PIC) is the other form of inorganic carbon found in the ocean. Most PIC is the CaCO that makes up shells of various marine organisms, but can also form in whiting events. Marine fish also excrete calcium carbonate during osmoregulation.
Some of the inorganic carbon species in the ocean, such as bicarbonate and carbonate, are major contributors to alkalinity, a natural ocean buffer that prevents drastic changes in acidity (or pH). The marine carbon cycle also affects the reaction and dissolution rates of some chemical compounds, regulates the amount of carbon dioxide in the atmosphere and Earth's temperature. | 0 | Theoretical and Fundamental Chemistry |
The Overhauser effect magnetometer or Overhauser magnetometer uses the same fundamental effect as the proton precession magnetometer to take measurements. By adding free radicals to the measurement fluid, the nuclear Overhauser effect can be exploited to significantly improve upon the proton precession magnetometer. Rather than aligning the protons using a solenoid, a low power radio-frequency field is used to align (polarise) the electron spin of the free radicals, which then couples to the protons via the Overhauser effect. This has two main advantages: driving the RF field takes a fraction of the energy (allowing lighter-weight batteries for portable units), and faster sampling as the electron-proton coupling can happen even as measurements are being taken. An Overhauser magnetometer produces readings with a 0.01 nT to 0.02 nT standard deviation while sampling once per second. | 0 | Theoretical and Fundamental Chemistry |
PDE5 is an enzyme that was first purified in 1980 from a rats lung. PDE5 converts intracellular cGMP to the nucleotide GMP. Many tissues contain PDE5, such as lungs, kidneys, brain, platelets, liver, prostate, urethra, bladder and smooth muscles. Because of the localization of PDE5 in the smooth muscle tissue, inhibitors were developed for the treatment of erectile dysfunction along with pulmonary hypertension.
Sildenafil was initially introduced for clinical trial in 1989. It was the result of extensive research on chemical agents targeting PDE5 that could be effective in treatment of coronary heart disease. Sildenafil did not prove effective for coronary heart disease but an interesting side effect was discovered, a penile erection. That side effect soon became the main field of investigation. The inhibitor is highly selective for the PDE5 family.
Sildenafil is a prototype of PDE5 inhibitors that Pfizer launched as Viagra. It was approved by the Food and Drug Administration (FDA) in 1998 as the first oral medicine for erectile dysfunction. Later, in the year 2005, it was approved for the treatment of pulmonary arterial hypertension. Vardenafil and tadalafil were discovered in 1990. These drugs came out of research programs focusing on finding PDE5 inhibitors for the treatment of cardiovascular diseases and erectile dysfunction. The two PDE5 inhibitors soon became treatments for these conditions.
Tadalafil is the most versatile inhibitor and has the longest half-life, 17.5 hours. This allows for a longer therapeutic window and is therefore often a more convenient drug than others with a shorter therapeutic window. Tadalafil is more bioavailable (80%) than sildenafil (40%) and vardenafil (15%) but it has a slow absorption, or about 2 hours compared to 50 minutes of sildenfil. Vardenafil is most known for its potency.
Because of severe adverse effects and patients dissatisfaction with current therapy choices other inhibitors have recently been approved for clinical use. These inhibitors are udenfil, avanafil lodenafil and mirodenafil. | 1 | Applied and Interdisciplinary Chemistry |
Born in Kalmar, Mosander attended school there until he moved to Stockholm with his mother in 1809. In Stockholm, he became an apprentice at the Ugglan pharmacy. He took his pharmacy examination in 1817, but had an interest in medicine and joined the Karolinska Institute in 1820. He passed his medical examination in 1825. He worked in the laboratory of Jöns Jakob Berzelius and became a close friend of fellow student Friedrich Wöhler. | 1 | Applied and Interdisciplinary Chemistry |
3′-UTR mutations can be very consequential because one alteration can be responsible for the altered expression of many genes. Transcriptionally, a mutation may affect only the allele and genes that are physically linked. However, since 3′-UTR binding proteins also function in the processing and nuclear export of mRNA, a mutation can also affect other unrelated genes. Dysregulation of ARE-binding proteins (AUBPs) due to mutations in AU-rich regions can lead to diseases including tumorigenesis (cancer), hematopoietic malignancies, leukemogenesis, and developmental delay/autism spectrum disorders. An expanded number of trinucleotide (CTG) repeats in the 3’-UTR of the dystrophia myotonica protein kinase (DMPK) gene causes myotonic dystrophy. Retro-transposal 3-kilobase insertion of tandem repeat sequences within the 3′-UTR of fukutin protein is linked to Fukuyama-type congenital muscular dystrophy. Elements in the 3′-UTR have also been linked to human acute myeloid leukemia, alpha-thalassemia, neuroblastoma, Keratinopathy, Aniridia, IPEX syndrome, and congenital heart defects. The few UTR-mediated diseases identified only hint at the countless links yet to be discovered. | 1 | Applied and Interdisciplinary Chemistry |
Rasagiline (Azilect, Azipron) is an irreversible inhibitor of monoamine oxidase-B used as a monotherapy to treat symptoms in early Parkinson's disease or as an adjunct therapy in more advanced cases.
The racemic form of the drug was invented by Aspro Nicholas in the early 1970s. Moussa B.H. Youdim identified it as a potential drug for Parkinson's disease, and working with collaborators at Technion – Israel Institute of Technology in Israel and the drug company, Teva Pharmaceuticals, identified the R-isomer as the active form of the drug. Teva brought it to market in partnership with Lundbeck in Europe and Eisai in the US and elsewhere. It was approved in Europe in 2005 and in the US in 2006.
Rasagiline is used to treat symptoms of Parkinson's disease both alone and in combination with other drugs. It has shown efficacy in both early and advanced Parkinsons, and appears to be especially useful in dealing with non-motor symptoms like fatigue.
Rasagiline has not been tested in pregnant women and is Pregnancy Category C in the US. | 0 | Theoretical and Fundamental Chemistry |
In the 1960s, Arthur C. Cope and Robert W. Siekman reported the cyclopalladation reaction between aromatic azobenzenes and palladium(II) dichloride. The potential of palladacycles as catalysts was highlighted by Herrmann's catalyst in 1990s. Derivatives of tris(o-tolyl)phosphine proved effective in Heck reactions. | 0 | Theoretical and Fundamental Chemistry |
A cDNA library is a collection of expressed DNA genes that are seen as a useful reference tool in gene identification and cloning processes. cDNA libraries are constructed from mRNA using RNA-dependent DNA polymerase reverse transcriptase (RT), which transcribes an mRNA template into DNA. Therefore, a cDNA library can only contain inserts that are meant to be transcribed into mRNA. This process relies on the principle of DNA/RNA complementarity. The end product of the libraries is double stranded DNA, which may be inserted into plasmids. Hence, cDNA libraries are a powerful tool in modern research. | 1 | Applied and Interdisciplinary Chemistry |
Several hundred metals, compounds, alloys and ceramics possess the property of superconductivity at low temperatures. The SU(2) color quark matter adjoins the list of superconducting systems. Although it is a mathematical abstraction, its properties are believed to be closely related to the SU(3)
color quark matter, which exists in nature when ordinary matter is compressed at supranuclear densities above ~ 0.5 10 nucleon/cm. | 0 | Theoretical and Fundamental Chemistry |
CREB regulated transcription coactivator 2, also known as CRTC2, is a protein which in humans is encoded by the CRTC2 gene. | 1 | Applied and Interdisciplinary Chemistry |
The model organism C. elegans is well studied; solid glycobiological literature have provided insights on the nematodal N-glycosylation machinery which shares many traits with other eukaryotic species. C. elegans is known to produce paucimannosidic proteins via a GnT-I-dependent route in which GnT-I firstly produces GlcNAc-capped glycoprotein intermediates. Further processing by two Hex isoenzymes (HEX-2 and HEX-3) encoded by two C. elegans genes (hex-2, hex-3) generate the unsubstituted C. elegans paucimannosidic glycans.
Other glycoenzymes catalise further processing and structural diversity including α-Man II and α1,6- and α1,3-fucosyltransferases. Albeit less active, a GnT-I-independent α1,6-fucosyltransferase has also been observed for C. elegans, indicating that both the GnT-I-dependent and -independent pathways may contribute to the formation of paucimannosidic N-glycoproteins in worms. However, the biosynthetic processes underpinning the unusual non-sugar and core-modified paucimannosidic N-glycans in C. elegans remain to be elucidated. | 1 | Applied and Interdisciplinary Chemistry |
Phycobilins are a third group of pigments found in cyanobacteria, and glaucophyte, red algal, and cryptophyte chloroplasts. Phycobilins come in all colors, though phycoerytherin is one of the pigments that makes many red algae red. Phycobilins often organize into relatively large protein complexes about 40 nanometers across called phycobilisomes. Like photosystem I and ATP synthase, phycobilisomes jut into the stroma, preventing thylakoid stacking in red algal chloroplasts. Cryptophyte chloroplasts and some cyanobacteria don't have their phycobilin pigments organized into phycobilisomes, and keep them in their thylakoid space instead. | 0 | Theoretical and Fundamental Chemistry |
Advanced Placement (AP) Chemistry (also known as AP Chem) is a course and examination offered by the College Board as a part of the Advanced Placement Program to give American and Canadian high school students the opportunity to demonstrate their abilities and earn college-level credits at certain colleges and universities. The AP Chemistry Exam has the lowest test participation rate out of all AP Courses, with around half of AP Chemistry students taking the exam. | 1 | Applied and Interdisciplinary Chemistry |
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