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In the context of zeolites, the term heteroatom refers to partial isomorphous substitution of the typical framework atoms (silicon, aluminium, and phosphorus) by other elements such as beryllium, vanadium, and chromium. The goal is usually to adjust properties of the material (e.g., Lewis acidity) to optimize the mater... | 0 | Organic Chemistry |
Nuclear DNA is normally tightly wrapped around histones rendering the DNA inaccessible to the general transcription machinery and hence this tight association prevents transcription of DNA. At physiological pH, the phosphate component of the DNA backbone is deprotonated which gives DNA a net negative charge. Histones... | 1 | Biochemistry |
An emulsion is a mixture of two or more liquids that are normally immiscible (unmixable or unblendable) owing to liquid-liquid phase separation. Emulsions are part of a more general class of two-phase systems of matter called colloids. Although the terms colloid and emulsion are sometimes used interchangeably, emulsion... | 7 | Physical Chemistry |
The transcriptome is the set of all RNA transcripts, including coding and non-coding, in an individual or a population of cells. The term can also sometimes be used to refer to all RNAs, or just mRNA, depending on the particular experiment. The term transcriptome is a portmanteau of the words transcript and genome; it ... | 1 | Biochemistry |
By analyzing the chemical composition of a cows rumen, researchers can determine the effects of different feeds and processes on bovine digestion. Many of the earliest documented reports of cannulated cows were made by researchers working to understand how feed is processed through cows. For instance, a 1939 study disc... | 1 | Biochemistry |
Neural stem cells (NSCs) in the brain must find a balance between maintaining their multipotency by self renewing and proliferating as opposed to differentiating and becoming quiescent. The PI3K/AKT pathway is crucial in this decision making process. NSCs are able to sense and respond to changes in the brain or through... | 1 | Biochemistry |
Carbon monoxide for FT catalysis is derived from hydrocarbons. In gas to liquids (GTL) technology, the hydrocarbons are low molecular weight materials that often would be discarded or flared. Stranded gas provides relatively cheap gas. For GTL to be commercially viable, gas must remain relatively cheaper than oil.
Sev... | 0 | Organic Chemistry |
The formation of new blood capillaries is an important component of pathological tissue repair in response to ischemia. The angiogenic process is complex and involves endothelial cell (EC) movement and proliferation.
SFRP1 has been shown to have a role in new vascularization after an ischemic event and as a potent ang... | 1 | Biochemistry |
Pyruvate kinase catalyzes the last step within the glycolytic sequence, the dephosphorylation of phosphoenolpyruvate to pyruvate and is responsible for net energy production within the glycolytic pathway. Depending upon the different metabolic functions of the tissues, different isoenzymes of pyruvate kinase are expres... | 1 | Biochemistry |
Briefly, SAGE experiments proceed as follows:
# The mRNA of an input sample (e.g. a tumour) is isolated and a reverse transcriptase and biotinylated primers are used to synthesize cDNA from mRNA.
# The cDNA is bound to Streptavidin beads via interaction with the biotin attached to the primers, and is then cleaved usi... | 1 | Biochemistry |
These have been no reports of serious adverse effects with overdose of drospirenone. Symptoms that may occur in the event of an overdose may include nausea, vomiting, and vaginal bleeding. There is no antidote for overdose of drospirenone and treatment of overdose should be based on symptoms. Since drospirenone has ant... | 4 | Stereochemistry |
p53 - package - palindromic sequence - palmitoyl acyltransferase - Parkinson's disease - pBR322 - PCR - pedigree - peptide - peptide-transporting ATPase - peptide bond - phage - phagemid - phenotype - phenylacetaldoxime dehydratase - PhIP-Seq - phosphatase, alkaline - phosphatidylcholine 12-monooxygenase - phosphatidyl... | 1 | Biochemistry |
"Molecular assemblers" have been confused with self-replicating machines. To produce a practical quantity of a desired product, the nanoscale size of a typical science fiction universal molecular assembler requires an extremely large number of such devices. However, a single such theoretical molecular assembler might b... | 6 | Supramolecular Chemistry |
In organosulfur chemistry, sulfinamide is a functional group with the structure (where R = alkyl or aryl). This functionality is composed of a sulfur-carbon () and sulfur-nitrogen () single bonds, as well as a sulfur-oxygen double bond (), resulting in a tetravalent sulfur centre (in resonance with its zwitterionic fo... | 0 | Organic Chemistry |
The stability of many (or most) organic radicals is not indicated by their isolability but is manifested in their ability to function as donors of H. This property reflects a weakened bond to hydrogen, usually O−H but sometimes N−H or C−H. This behavior is important because these H donors serve as antioxidants in biolo... | 2 | Environmental Chemistry |
A deformation mechanism map is a way of representing the dominant deformation mechanism in a material loaded under a given set of conditions. The technique is applicable to all crystalline materials, metallurgical as well as geological. Additionally, work has been conducted regarding the use of deformation maps to nano... | 8 | Metallurgy |
Methylene blue is a dye behaving as a redox indicator that is commonly used in the food industry to test the freshness of milk and dairy products. A few drops of methylene blue solution added to a sample of milk should remain blue (oxidized form in the presence of enough dissolved ), otherwise (discoloration caused by ... | 3 | Analytical Chemistry |
The carbon atom at which the initial deprotonation takes place is a stereocenter. If, for example, D-glucose (an Aldose) rearranges to D-fructose, the ketose, the stereochemical configuration is lost in the enol form. In the chemical reaction the enol can be protonated from two faces, resulting in the backformation o... | 0 | Organic Chemistry |
Pancuronium remains one of the few muscle relaxants logically and rationally designed from structure-action / effects relationship data. A steroid skeleton was chosen because of its appropriate size and rigidness. Acetylcholine moieties were inserted to increase receptor affinity. Although having many unwanted side-eff... | 1 | Biochemistry |
Microbial dark matter comprises the vast majority of microbial organisms (usually bacteria and archaea) that microbiologists are unable to culture in the laboratory, due to lack of knowledge or ability to supply the required growth conditions. Microbial dark matter is unrelated to the dark matter of physics and cosmolo... | 1 | Biochemistry |
Several photons of energy below the ionization threshold may actually combine their energies to ionize an atom. This probability decreases rapidly with the number of photons required, but the development of very intense, pulsed lasers still makes it possible. In the perturbative regime (below about 10 W/cm at optical f... | 7 | Physical Chemistry |
Demethylation often refers to cleavage of ethers, especially aryl ethers.
Historically, aryl methyl ethers, including natural products such as codeine (O-methylmorphine), have been demethylated by heating the substance in molten pyridine hydrochloride (melting point ) at , sometimes with excess hydrogen chloride, in a ... | 0 | Organic Chemistry |
Metabolic control analysis (MCA) is a mathematical framework for describing
metabolic, signaling, and genetic pathways. MCA quantifies how variables, such as fluxes and species concentrations, depend on network parameters.
In particular, it is able to describe how network-dependent properties,
called control coefficie... | 1 | Biochemistry |
In physics, the cross section is a measure of the probability that a specific process will take place in a collision of two particles. For example, the Rutherford cross-section is a measure of probability that an alpha particle will be deflected by a given angle during an interaction with an atomic nucleus. Cross sect... | 7 | Physical Chemistry |
Sulfidic (or euxinic) conditions, which exist today in many water bodies from ponds to various land-surrounded mediterranean seas such as the Black Sea, were particularly prevalent in the Cretaceous Atlantic but also characterised other parts of the world ocean. In an ice-free sea of these supposed super-greenhouse wor... | 9 | Geochemistry |
Exposure to UV radiation is associated with skin aging, wrinkle production, liver spots, loss of skin elasticity, erythema (reddening of the skin), sunburn, photokeratitis (snow blindness), ocular melanoma (eye cancer), and infections. Tanning beds can contain many microbes, some of which are pathogens that can cause s... | 5 | Photochemistry |
Several hormones can affect insulin secretion. Estrogen is correlated with an increase of insulin secretion by depolarizing the β-cells membrane and enhancing the entry of Ca+2. In contrast, growth hormone is known to lower the serum level of insulin by promoting the production of insulin-like growth factor-I (IGF-I). ... | 1 | Biochemistry |
Another Henry's law solubility constant is:
Here is the molar mixing ratio in the aqueous phase. For a dilute aqueous solution the conversion between and is:
where is the density of water and is the molar mass of water. Thus
The SI unit for is Pa, although atm is still frequently used. | 7 | Physical Chemistry |
In interferometric microscopy, the image of a micro-object is synthesized numerically as a coherent combination
of partial images with registered amplitude and phase.
For registration of partial images, a conventional holographic set-up is used with a reference wave, as is usual in optical holography. Capturing multipl... | 7 | Physical Chemistry |
Most proteins that are translated from mRNA undergo modifications before becoming functional in cells. These modifications are collectively known as post-translational modifications. The nascent or folded proteins, which are stable under physiological conditions, are then subjected to a battery of specific enzyme-catal... | 0 | Organic Chemistry |
Yuan Tseh Lee (; born 19 November 1936) is a Taiwanese chemist. He is a Professor Emeritus at the University of California, Berkeley. He was the first Taiwanese Nobel Prize laureate who, along with the Hungarian-Canadian John C. Polanyi and American Dudley R. Herschbach, won the Nobel Prize in Chemistry in 1986 "for th... | 7 | Physical Chemistry |
Lead(II) fluoride is used in low melting glasses, in glass coatings to reflect infrared rays, in phosphors for television-tube screens, and as a catalyst for the manufacture of picoline. The Muon g−2 experiment uses scintillators in conjunction with silicon photomultipliers. | 0 | Organic Chemistry |
Substances that have the ability to reduce other substances (cause them to gain electrons) are said to be reductive or reducing and are known as reducing agents, reductants, or reducers. The reductant transfers electrons to another substance and is thus itself oxidized. Because it donates electrons, the reducing agent ... | 9 | Geochemistry |
Enone–alkene cycloadditions can produce two isomers, depending on the orientation of substituents on the alkene and the enone carbonyl group. When the enone carbonyl and substituent of highest priority are proximal, the isomer is termed "head-to-head." When the enone carbonyl and substituent are distal, the isomer is c... | 5 | Photochemistry |
PKA has always been considered important in formation of a memory. In the fruit fly, reductions in expression activity of DCO (PKA catalytic subunit encoding gene) can cause severe learning disabilities, middle term memory and short term memory. Long term memory is dependent on the CREB transcription factor, regulated ... | 1 | Biochemistry |
LTR retrotransposons came about later than non-LTR retrotransposons, possibly from an ancestral non-LTR retrotransposon acquiring an integrase from a DNA transposon. Retroviruses gained additional properties to their virus envelopes by taking the relevant genes from other viruses using the power of LTR retrotransposon.... | 1 | Biochemistry |
Initially in the process of degradation, fatty acids are stored in adipocytes. The breakdown of this fat is known as lipolysis. The products of lipolysis, free fatty acids, are released into the bloodstream and circulate throughout the body. During the breakdown of triacylglycerols into fatty acids, more than 75% of th... | 1 | Biochemistry |
In atmospheric radiation, Chandrasekhars X- and Y-function appears as the solutions of problems involving diffusive reflection and transmission, introduced by the Indian American astrophysicist Subrahmanyan Chandrasekhar. The Chandrasekhars X- and Y-function
where the characteristic function is an even polynomial in ... | 7 | Physical Chemistry |
A hyperaccumulator is a plant capable of growing in soil or water with high concentrations of metals, absorbing these metals through their roots, and concentrating extremely high levels of metals in their tissues. The metals are concentrated at levels that are toxic to closely related species not adapted to growing on... | 2 | Environmental Chemistry |
A transcription bubble is a molecular structure formed during DNA transcription when a limited portion of the DNA double helix is unwound. The size of a transcription bubble ranges from 12 to 14 base pairs. A transcription bubble is formed when the RNA polymerase enzyme binds to a promoter and causes two DNA strands to... | 1 | Biochemistry |
Rouging is a form of corrosion found in stainless steel. It can be due to iron contamination of the stainless steel surface due to welding of non-stainless steel for support columns, or other temporary means, which when welded off leaves a low chromium area.
There are three classes of rouging: Class I, Class II, and Cl... | 8 | Metallurgy |
Coal tar was formerly one of the products of gasworks. Tar made from coal or petroleum is considered toxic and carcinogenic because of its high benzene content, though coal tar in low concentrations is used as a topical medicine for conditions such as psoriasis. Coal and petroleum tar has a pungent odor.
Coal tar is ... | 7 | Physical Chemistry |
Sawdust (or wood dust) is a by-product or waste product of woodworking operations such as sawing, sanding, milling and routing. It is composed of very small chips of wood. These operations can be performed by woodworking machinery, portable power tools or by use of hand tools. In some manufacturing industries it can ... | 2 | Environmental Chemistry |
Deuterium is often represented by the chemical symbol D. Since it is an isotope of hydrogen with mass number 2, it is also represented by H. IUPAC allows both D and H, though H is preferred. A distinct chemical symbol is used for convenience because of the isotopes common use in various scientific processes. Also, its ... | 9 | Geochemistry |
The single-cell eukaryote Paramecium tetraurelia can undergo both asexual and sexual reproduction. Asexual or clonal reproduction occurs by binary fission. Binary fission involves mitosis-like behavior of the chromosomes similar to that of cells in higher organisms. The sexual forms of reproduction are autogamy, a k... | 1 | Biochemistry |
Chemical and geological evidence indicate that photosynthetic cyanobacteria existed about 2.6 billion years ago and anoxygenic photosynthesis had been taking place since a billion years before that. Oxygenic photosynthesis was the primary source of free oxygen and led to the Great Oxidation Event roughly 2.4 to 2.1 bil... | 5 | Photochemistry |
A similar analysis, done by J. M. Harris, has been applied to the competing S1 and S2 nucleophilic aliphatic substitution pathways. The effects of increasing the nucleophilicity of the nucleophile are shown as an example in Figure 3. An agreement with Hammet ρ-values is also apparent in this application. | 7 | Physical Chemistry |
Protein Data Bank in Europe – Knowledge Base (PDBe-KB) is a community-driven, open-access, integrated resource whose mission is to place macromolecular structure data in their biological context and to make them accessible to the scientific community in order to support fundamental and translational research and educat... | 1 | Biochemistry |
Retinal is bound to opsins, which are G protein-coupled receptors (GPCRs). Opsins, like other GPCRs, have seven transmembrane alpha-helices connected by six loops. They are found in the photoreceptor cells in the retina of eye. The opsin in the vertebrate rod cells is rhodopsin. The rods form disks, which contain the r... | 1 | Biochemistry |
Christopher J. Chetsanga (born 1935 in Murehwa, Rhodesia) is a prominent Zimbabwean scientist who is a member of the African Academy of Sciences and The World Academy of Sciences. He discovered two enzymes involved in DNA repair. He has also held various academic administrative posts like Vice-Chancellor, Director and ... | 1 | Biochemistry |
Its activities are focused on both fundamental objectives in analytical sciences and interactions with the socio-economic environment at local, national and international levels. The Institute has partnerships with international research centers (e.g. MIT, the École Polytechnique Fédérale de Lausanne, International Age... | 3 | Analytical Chemistry |
The established performance criteria, definitions, and nomenclature for electrochemical engineering can be found in Kreysa et al. and an IUPAC report. | 7 | Physical Chemistry |
Compared to concentration dependent bactericidal antibiotics like aminoglycosides and fluoroquinolones, the antibacterial activity of β-lactam antibiotics are generally more time dependent. Unlike the former, when piperacillin-tazobactam concentrations exceed minimum inhibitory concentrations (MIC) of a pathogen by fiv... | 4 | Stereochemistry |
Synthetic accessibility is a simple approach to network simulation whose goal is to predict which metabolic gene knockouts are lethal. The synthetic accessibility approach uses the topology of the metabolic network to calculate the sum of the minimum number of steps needed to traverse the metabolic network graph from t... | 1 | Biochemistry |
Histidine methyl ester (HME) is an irreversible histidine decarboxylase inhibitor. It is the methyl ester of histidine. | 1 | Biochemistry |
* Furaneol (strawberry)
* 1-Hexanol (herbaceous, woody)
* cis-3-Hexen-1-ol (fresh cut grass)
* Menthol (peppermint) | 0 | Organic Chemistry |
The tetrazole-alkene "photoclick" reaction is another dipolar addition that Huisgen first introduced in the late 1960s ChemBioChem 2007, 8, 1504. (68) Clovis, J. S.; Eckell, A.; Huisgen, R.; Sustmann, R. Chem. Ber. 1967, 100, 60.) Tetrazoles with amino or styryl groups that can be activated by UV light at 365 nm (365 d... | 0 | Organic Chemistry |
The molar gas constant (also known as the gas constant, universal gas constant, or ideal gas constant) is denoted by the symbol or . It is the molar equivalent to the Boltzmann constant, expressed in units of energy per temperature increment per amount of substance, rather than energy per temperature increment per par... | 7 | Physical Chemistry |
RNA-targeting small molecule drug discovery has greatly benefitted from the available cellular models for disease. The use of cell culture in early development has become a requirement for assessing the basic efficacy of a drug candidate. Thus, more research groups have implemented these techniques in their programs. I... | 1 | Biochemistry |
A biosignature must be able to last for long enough so that a probe, telescope, or human can be able to detect it. A consequence of a biological organism's use of metabolic reactions for energy is the production of metabolic waste. In addition, the structure of an organism can be preserved as a fossil and we know that ... | 2 | Environmental Chemistry |
As an example camphor tosylhydrazone is synthesised from camphor and tosylhydrazine in ethanol with hydrochloric acid catalysis. | 0 | Organic Chemistry |
Live cell imaging and proteomic studies have allowed researchers at the centre to gain fresh understanding of protein function and cell behaviour.
The centre is studying many aspects of the cell cycle, including the way in which chromosomes replicate and separate during cell division and how DNA damage is detected. Fai... | 1 | Biochemistry |
Van der Waals strain, or steric strain, occurs when atoms are forced to get closer than their Van der Waals radii allow. Specifically, Van der Waals strain is considered a form of strain where the interacting atoms are at least four bonds away from each other. The amount on steric strain in similar molecules is depend... | 4 | Stereochemistry |
While lipolysis is triglyceride hydrolysis (the process by which triglycerides are broken down), esterification is the process by which triglycerides are formed. Esterification and lipolysis are, in essence, reversals of one another. | 1 | Biochemistry |
In 1902, The Electrochemical Society (ECS) was founded.
In 1909, Robert Andrews Millikan began a series of experiments (see oil drop experiment) to determine the electric charge carried by a single electron.
In 1911, Harvey Fletcher, working with Millikan, was successful in measuring the charge on the electron, by repl... | 7 | Physical Chemistry |
Another form of amylase, β-amylase () (alternative names: 1,4-α--glucan maltohydrolase; glycogenase; saccharogen amylase) is also synthesized by bacteria, fungi, and plants. Working from the non-reducing end, β-amylase catalyzes the hydrolysis of the second α-1,4 glycosidic bond, cleaving off two glucose units (maltos... | 1 | Biochemistry |
Petroleum, also known as crude oil or simply oil, is a naturally occurring yellowish-black liquid mixture of mainly hydrocarbons, and is found in geological formations. The name petroleum covers both naturally occurring unprocessed crude oil and petroleum products that consist of refined crude oil.
Petroleum is primari... | 7 | Physical Chemistry |
A meta-analysis of observational studies showed that children with ADHD have lower vitamin D levels, and that there was a small association between low vitamin D levels at the time of birth and later development of ADHD. Several small, randomized controlled trials of vitamin D supplementation indicated improved ADHD sy... | 1 | Biochemistry |
Single nucleotide variant can also affect the cis-acting regulatory elements in mRNA’s to inhibit/promote the translation initiation. Change in the synonymous codons region due to mutation may affect the translation efficiency because of codon usage biases. The translation elongation can also be retarded by mutations a... | 1 | Biochemistry |
Many contaminated brownfield sites sit unused for decades because the cost of cleaning them to safe standards is more than the land would be worth after redevelopment, in the process becoming involuntary parks as they grow over. However, redevelopment has become more common in the first decade of the 21st century, as d... | 2 | Environmental Chemistry |
Imine formation is an important reaction. Primary amines react with ketones and aldehydes to form imines. In the case of formaldehyde (R' H), these products typically exist as cyclic trimers.
Reduction of these imines gives secondary amines:
Similarly, secondary amines react with ketones and aldehydes to form enamines... | 0 | Organic Chemistry |
For the simplest embodiment of linearly-polarized microwave scattering in the absence of magnetic depolarization, three regimes may arise due to the correlation between scatterers. The Thomson regime refers to free plasma electrons oscillating in-phase with the incident microwave field. The total scattering cross-secti... | 7 | Physical Chemistry |
It is prepared in the laboratory by disproportionation of phosphorous acid:
Alternative methods are the hydrolysis of tris(trimethylsilyl)phosphine, or of metal phosphides such as aluminium phosphide, or calcium phosphide:
Pure samples of phosphine, free from , may be prepared using the action of potassium hydroxide on... | 0 | Organic Chemistry |
There is no conclusive evidence that thalidomide or lenalidomide is useful to bring about or maintain remission in Crohn's disease.
Thalidomide was studied in a Phase II trial for Kaposis sarcoma, a rare soft-tissue cancer most commonly seen in the immunocompromised, that is caused by the Kaposis sarcoma-associated her... | 4 | Stereochemistry |
Clark has an undergraduate degree in geological sciences completed at The State University of New York at Geneseo in 2013, a master's degree in geological sciences from The University of Alabama completed in 2015, and a PhD in geological and earth sciences completed at The University of Houston in 2021. | 9 | Geochemistry |
Extracellular binding of cytokines or growth factors induce activation of receptor-associated Janus kinases, which phosphorylate a specific tyrosine residue within the STAT protein promoting dimerization via their SH2 domains. The phosphorylated dimer is then actively transported to the nucleus via an importin α/β tern... | 1 | Biochemistry |
The gram per cubic centimetre is a unit of density in the CGS system, and is commonly used in chemistry. It is defined by dividing the CGS unit of mass, the gram, by the CGS unit of volume, the cubic centimetre. The official SI symbols are g/cm, g·cm, or g cm. It is equivalent to the units gram per millilitre (g/mL) an... | 3 | Analytical Chemistry |
Bisulfite sequencing relies on the conversion of every single unmethylated cytosine residue to uracil. If conversion is incomplete, the subsequent analysis will incorrectly interpret the unconverted unmethylated cytosines as methylated cytosines, resulting in false positive results for methylation. Only cytosines in si... | 1 | Biochemistry |
Hidden stops are non-stop codons that would be read as stop codons if they were frameshifted +1 or −1. These prematurely terminate translation if the corresponding frame-shift (such as due to a ribosomal RNA slip) occurs before the hidden stop. It is hypothesised that this decreases resource wastage on nonfunctional pr... | 1 | Biochemistry |
The development of an analytical instrument that utilizes the reduction-oxidation (redox) chemistry of oxygen in the presence of dissimilar metal electrodes was introduced during the 1950s. This redox electrode utilized an oxygen-permeable membrane to allow the diffusion of the gas into an electrochemical cell and its ... | 3 | Analytical Chemistry |
Hyrax midden structures and accumulation rates can vary considerably based on the relative proportion of their two primary components, pellets and hyraceum, which is determined by the architecture of the site itself. Depending on the shape and irregularities of the floor of the site in question, pellets are likely to e... | 9 | Geochemistry |
The Patterson function is used to solve the phase problem in X-ray crystallography. It was introduced in 1935 by Arthur Lindo Patterson while he was a visiting researcher in the laboratory of Bertram Eugene Warren at MIT.
The Patterson function is defined as
It is essentially the Fourier transform of the intensities ra... | 3 | Analytical Chemistry |
In organometallic chemistry, acetylide refers to chemical compounds with the chemical formulas and , where M is a metal. The term is used loosely and can refer to substituted acetylides having the general structure (where R is an organic side chain). Acetylides are reagents in organic synthesis. The calcium acetyli... | 0 | Organic Chemistry |
As mentioned above, the CCE separates cells based on their sedimentation property but not specific features (e.g. surface protein, cell shape). It cannot separate different types of cells which have similar sedimentation properties. This means that previous purification needs to be done for mixed cell type sample. The ... | 3 | Analytical Chemistry |
Candidate gene association study is commonly used in genetic study before the invention of high throughput genotyping or sequencing technologies. Candidate gene association study is to investigate limited number of pre-specified SNPs for association with diseases or clinical phenotypes or traits. So this is a hypothesi... | 1 | Biochemistry |
When the mean free path of an atom is much smaller than the wavelength of the radiative transition, the atom changes velocity and direction many times during the emission or absorption of a photon. This causes an averaging over different Doppler states and results in an atomic linewidth that is narrower than the Dopple... | 7 | Physical Chemistry |
The first clear advantage of chain shuttling is that one can design copolymers with more desirable traits. A polymer that is normally semi crystalline and rigid can be altered so that it has a lower glass transition temperature. An amorphous, elastic polymer membrane can be altered to have a higher melting point. The... | 7 | Physical Chemistry |
From the 7th to 3rd Century BC, the Scythian people of the Pontic–Caspian steppe engaged in the widespread practice of metallurgy. Though Scythian society was heavily based around a nomadic, mobile lifestyle, the culture was capable of practicing metallurgy and of producing metal objects. Many works of Scythian metalwo... | 8 | Metallurgy |
The electrochemist John Bockris proposed the words electronation and deelectronation to describe reduction and oxidation processes, respectively, when they occur at electrodes. These words are analogous to protonation and deprotonation. They have not been widely adopted by chemists worldwide, although IUPAC has recogni... | 9 | Geochemistry |
*Estimation of the size of DNA molecules following restriction enzyme digestion, e.g. in restriction mapping of cloned DNA.
*Analysis of PCR products, e.g. in molecular genetic diagnosis or genetic fingerprinting
*Separation of restricted genomic DNA prior to Southern transfer, or of RNA prior to Northern transfer.
Gel... | 1 | Biochemistry |
The TOC complex, or translocon on the outer chloroplast membrane, is a collection of proteins that imports preproteins across the outer chloroplast envelope. Five subunits of the TOC complex have been identified—two GTP-binding proteins Toc34 and Toc159, the protein import tunnel Toc75, plus the proteins Toc64 and Toc1... | 5 | Photochemistry |
According to some scholars, lost-wax casting was used in China already during the Spring and Autumn period (770 – 476 BCE), although this is often disputed.
The lost-wax method is used in most parts of the world. As the name suggests, the lost-wax method is to use wax as a mold, and heat it to melt the wax mold and los... | 8 | Metallurgy |
Senapathy addressed the origin of the spliceosomal machinery that edits out the introns from RNA transcripts. If the split genes had originated from random DNA, then the introns would have become an unnecessary but integral part of eukaryotic genes along with the splice junctions. The spliceosomal machinery would be re... | 1 | Biochemistry |
There are at least three other possible resolutions to the Kauzmann paradox. It could be that the heat capacity of the supercooled liquid near the Kauzmann temperature smoothly decreases to a smaller value. It could also be that a first order phase transition to another liquid state occurs before the Kauzmann temperatu... | 7 | Physical Chemistry |
Acetalisation is the organic reaction that involves the formation of an acetal (or ketals). One way of acetal formation is the nucleophilic addition of an alcohol to a ketone or an aldehyde. Acetalisation is often used in organic synthesis to create a protecting group because it is a reversible reaction.
Acetalisation ... | 0 | Organic Chemistry |
Spectroscopy measures the interaction of the molecules with electromagnetic radiation. Spectroscopy consists of many different applications such as atomic absorption spectroscopy, atomic emission spectroscopy, ultraviolet-visible spectroscopy, X-ray fluorescence spectroscopy, infrared spectroscopy, Raman spectroscopy, ... | 3 | Analytical Chemistry |
Spectrum analyzer types are distinguished by the methods used to obtain the spectrum of a signal. There are swept-tuned and fast Fourier transform (FFT) based spectrum analyzers:
*A swept-tuned analyzer uses a superheterodyne receiver to down-convert a portion of the input signal spectrum to the center frequency of a n... | 7 | Physical Chemistry |
This detector usually consists of a heated thin filament or ribbon of a metal with a high work function (typically tungsten or rhenium). Neutral atoms or molecules that strike the filament can boil off as positive ions in a process known as surface ionization, and these may be either measured as a current or detected, ... | 3 | Analytical Chemistry |
In protein structures determined by X-ray crystallography, poor peptide-plane geometry has been described as a common problem; many structures need correction by peptide-plane flips or peptide bond flips. | 1 | Biochemistry |
Because of its ability to cause chemical reactions and excite fluorescence in materials, ultraviolet radiation has a number of applications. The following table gives some uses of specific wavelength bands in the UV spectrum.
* 13.5 nm: Extreme ultraviolet lithography
* 30–200 nm: Photoionization, ultraviolet photoelec... | 5 | Photochemistry |
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