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The spectral power distribution (SPD) of a source describes how much flux reaches the sensor over a particular wavelength and area. This effectively expresses the per-wavelength contribution to the radiometric quantity being measured. The SPD of a source is commonly shown as an SPD curve. SPD curves provide a visual re...
7
Physical Chemistry
The primary use of dextromethorphan is as a cough suppressant, for the temporary relief of cough caused by minor throat and bronchial irritation (such as commonly accompanies the flu and common cold), or from inhaled particle irritants, as well as chronic cough at a higher dosage. Dextromethorphan is available alone in...
4
Stereochemistry
The preferred scenario for good tilth is as the result of natural soil-building processes, provided by the activity of plant roots, microorganisms, earthworms and other beneficial organisms. Such stable aggregates break apart during tillage/planting and readily provide good tilth. Soil biota and organic matter work in ...
9
Geochemistry
Metabolic fluxes are a function of gene expression, translation, post translational protein modifications and protein-metabolite interactions.
1
Biochemistry
In nature, denitrification can take place in both terrestrial and marine ecosystems. Typically, denitrification occurs in anoxic environments, where the concentration of dissolved and freely available oxygen is depleted. In these areas, nitrate (NO) or nitrite () can be used as a substitute terminal electron acceptor i...
1
Biochemistry
Formylation of octabase prior to cyclization avoids ether cleavage as a side reaction and yields higher than without N-substitution or N-methylation. In this example, the purification was done by formation of a brucine salt. This process has also been patented by Roche.
4
Stereochemistry
High light increases leaf thickness, either because of an increase in the number of cell layers within the leaf, and/or because of an increase in the cell size within a cell layer. The density of a leaf increases as well, and so does the leaf dry mass per area (LMA). There are also more stomata per mm2.
5
Photochemistry
Full article: Ocean acidification The pH of the oceans is declining due to uptake of atmospheric CO. The rise in dissolved carbon dioxide reduces the availability of the carbonate ion, reducing CaCO saturation state, thus making it thermodynamically harder to make CaCO shell. Carbonate ions preferentially bind to hydr...
9
Geochemistry
One method of measuring FRET efficiency is to measure the variation in acceptor emission intensity. When the donor and acceptor are in proximity (1–10 nm) due to the interaction of the two molecules, the acceptor emission will increase because of the intermolecular FRET from the donor to the acceptor. For monitoring pr...
1
Biochemistry
Many liquids are used as solvents, to dissolve other liquids or solids. Solutions are found in a wide variety of applications, including paints, sealants, and adhesives. Naphtha and acetone are used frequently in industry to clean oil, grease, and tar from parts and machinery. Body fluids are water-based solutions. Sur...
7
Physical Chemistry
The first protein to be classified as a suppressor of cytokine signaling, CIS (cytokine-inducible SH2), was discovered in 1995, when it was found to have a unique ability to regulate cytokine signal transduction.
1
Biochemistry
A relatively recent work (2006) by Fernández and Frenking (2006) summarized the trends in hyperconjugation among various groups of acyclic molecules, using energy decomposition analysis or EDA. Fernández and Frenking define this type of analysis as "...a method that uses only the pi orbitals of the interacting fragment...
7
Physical Chemistry
Since skeletal structures were introduced in the latter half of the 19th century, their appearance has undergone considerable evolution. The graphical conventions in use today date to the 1980s. Thanks to the adoption of the ChemDraw software package as a de facto industry standard (by American Chemical Society, Royal ...
0
Organic Chemistry
Antibodies serve various functions in protecting the host against the pathogen. Their soluble forms which carry out these functions are produced by plasma B cells, a type of white blood cell. This production is tightly regulated and requires the activation of B cells by activated T cells (another type of white blood ce...
1
Biochemistry
In June 2023, astronomers detected, for the first time outside the Solar System, methyl cation, CH (and/or carbon cation, C), the known basic ingredients of life, in interstellar space.
7
Physical Chemistry
Lipofuscin quantification is used for age determination in various crustaceans such as lobsters and spiny lobsters. Since these animals lack bony parts, they cannot be aged in the same way as bony fish, in which annual increments in the ear-bones or otoliths are commonly used. Age determination of fish and shellfish is...
1
Biochemistry
In Gram-negative bacteria, e.g. Escherichia coli, PDC consists of a central cubic core made up from 24 molecules of dihydrolipoyl transacetylase (E2). Up to 16 homodimers of pyruvate dehydrogenase (E1) and 8 homodimers of dihydrolipoyl dehydrogenase (E3) bind to the E2 PSBD around the E2 core. In Gammaproteobacteria, ...
1
Biochemistry
In vivo, AGEs form pentosidine through sugar fragmentation. In patients with diabetes mellitus type 2, pentosidine correlates with the presence and severity of diabetic complications.
1
Biochemistry
Evolution in bacteria was previously viewed as a result of mutation or genetic drift. Today, genetic exchange, or gene transfer is viewed as a major driving force in the evolution of prokaryotes. This driving force has been widely studied in organisms like E. coli. Bacteria reproduces asexually, where daughter cells ar...
1
Biochemistry
Cyclopropyl cyanide, when heated to 660-760K and under pressure of 2-89torr, becomes cis and trans crotonitrile and allyl cyanide molecules, with some presence of methacrylonitrile. This is an isomerization reaction that is homogeneous with rate of first order. The reaction result is due to the biradical mechanism, wh...
7
Physical Chemistry
Ivan Ivanovich Ostromislensky (, also Iwan Ostromislensky) (9 September 1880 – 16 January 1939) was a Russian organic chemist. He is credited as the pioneer in studying polymerization of synthetic rubber as well as inventor of various industrial technologies for production of synthetic rubber, polymers and pharmaceutic...
0
Organic Chemistry
Ammonium carbamate solutions are highly corrosive to metallic construction materials – even to resistant forms of stainless steel – especially in the hottest parts of the synthesis plant such as the stripper. Historically corrosion has been minimized (although not eliminated) by continuous injection of a small amount o...
7
Physical Chemistry
These list include codes that do not qualify for the previous section. The reasons may include the following: source code is not available, FFT acceleration is absent or reduced, the code focuses on specific applications not allowing easy calculation of standard scattering quantities.
7
Physical Chemistry
In female elephants, the two compounds 3-ethyl phenol and 2-ethyl 4,5 dimethylphenol have been detected in urine samples. Temporal glands secretion examination showed the presence of phenol, m-cresol and p-cresol (4-methyl phenol) during musth in male elephants. p-Cresol and o-cresol are also components of the human sw...
0
Organic Chemistry
Thienamycin (also known as thienpenem) is one of the most potent naturally produced antibiotics known thus far, discovered in Streptomyces cattleya in 1976. Thienamycin has excellent activity against both Gram-positive and Gram-negative bacteria and is resistant to bacterial β-lactamase enzymes. Thienamycin is a zwit...
0
Organic Chemistry
An important parameter in wet scrubbing systems is the rate of liquid flow. It is common in wet scrubber terminology to express the liquid flow as a function of the gas flow rate that is being treated. This is commonly called the liquid-to-gas ratio (L/G ratio) and uses the units of gallons per 1,000 actual cubic feet ...
3
Analytical Chemistry
* Bacteroides spp., including B. fragilis * Enterobacter spp. * Escherichia coli * Haemophilus influenzae * Klebsiella species * Morganella morganii * Neisseria gonorrhoeae * Proteus mirabilis * Proteus vulgaris * Providencia rettgeri * Pseudomonas spp., including P. aeruginosa * Serratia marcescens
4
Stereochemistry
Components of a typical THz-TDS instrument, as illustrated in the figure, include an infrared laser, optical beamsplitters, beam steering mirrors, delay stages, a terahertz generator, terahertz beam focusing and collimating optics like parabolic mirrors, and detector.
7
Physical Chemistry
The journal is indexed in Index Medicus/PubMed/MEDLINE, Index Veterinarius, CAB Abstracts, Biological Abstracts, BIOSIS Previews, Current Contents/Life Sciences, ProQuest, Science Citation Index, and others. According to the Journal Citation Reports, its 2019 impact factor is 4.060, ranking it 102nd out of 297 journals...
1
Biochemistry
The rare, but naturally occurring amino acid selenocysteine (Sec), can also be found as the nucleophile in some catalytic triads. Selenocysteine is similar to cysteine, but contains a selenium atom instead of a sulfur. An example is in the active site of thioredoxin reductase, which uses the selenium for reduction of d...
1
Biochemistry
While rich veins of tin are known to exist in Central and South Africa, whether these were exploited during ancient times is still debated . However, the Bantu culture of Zimbabwe are known to have actively mined, smelted and traded tin between the 11th and 15th centuries AD.
8
Metallurgy
The only known place in the universe where the baryon density might possibly be high enough to produce quark matter, and the temperature is low enough for color superconductivity to occur, is the core of a compact star (often called a "neutron star", a term which prejudges the question of its actual makeup). There are ...
7
Physical Chemistry
These catalysts are metallocenes together with a cocatalyst, typically MAO, −[O−Al(CH)]−. The idealized metallocene catalysts have the composition CpMCl (M = Ti, Zr, Hf) such as titanocene dichloride. Typically, the organic ligands are derivatives of cyclopentadienyl. In some complexes, the two cyclopentadiene (Cp) rin...
7
Physical Chemistry
Derepression of translation increases protein production without altering the levels of mRNA in the cell. miRNAs are a common mechanism of translation repression, binding to the mRNA through complementary base pairing to silence them. Certain RNA binding proteins have been shown to target untranslated regions of the mR...
1
Biochemistry
In 1910 British polar explorer Robert Scott hoped to be the first to reach the South Pole, but was beaten by Norwegian explorer Roald Amundsen. On foot, the expedition trudged through the frozen deserts of the Antarctic, marching for caches of food and kerosene deposited on the way. In early 1912, at the first cache, t...
8
Metallurgy
Generally, when reactions take place in the liquid and solid phases the change in volume due to reaction is not significant enough that it needs to be taken into account. Reactions in the gas phase often have significant changes in volume and in these cases one should use these modified equations.
9
Geochemistry
A human artificial chromosome (HAC) is a microchromosome that can act as a new chromosome in a population of human cells. That is, instead of 46 chromosomes, the cell could have 47 with the 47th being very small, roughly 6–10megabases (Mb) in size instead of 50–250Mb for natural chromosomes, and able to carry new genes...
1
Biochemistry
A pesticide is a substance or a mixture of substances used for killing pests: organisms dangerous to cultivated plants or to animals. The term applies to various pesticides such as insecticide, fungicide, herbicide and nematocide. The definition of residue of pesticide according to the world health organisation (WHO)...
2
Environmental Chemistry
Woodchuck Hepatitis Virus (WHV) Posttranscriptional Regulatory Element (WPRE) is a DNA sequence that, when transcribed, creates a tertiary structure enhancing expression. The sequence is commonly used in molecular biology to increase expression of genes delivered by viral vectors. WPRE is a tripartite regulatory elemen...
1
Biochemistry
Given the biochemical network: where and are fixed species to ensure the system is open. The system equation can be written as: So that: The elements of the rate vector will be rate equations that are functions of one or more species and parameters, p. In the example, these might be simple mass-action rate laws such...
1
Biochemistry
Benzeneselenol is prepared by the reaction of phenylmagnesium bromide and selenium: :PhMgBr + Se → PhSeMgBr :PhSeMgBr + HCl → PhSeH + MgBrCl Since benzeneselenol does not have a long shelf life, it is often generated in situ. A common method is by reduction of diphenyldiselenide. A further reason for this conversion is...
0
Organic Chemistry
Gerel Ochir (; born 17 July 1941) is a Mongolian geologist. She specializes in petrology, geochemistry, and metallogeny. She has taught at the Mongolian University of Science and Technology for over 50 years and headed the Department of Geology for 30 years. After earning bachelors and masters degrees in geology, geoch...
9
Geochemistry
Gemperline completed both undergraduate and graduate studies at Cleveland State University (CSU), graduating with a Bachelor of Science in Chemistry in 1978 and a Ph.D. in Analytical Chemistry in 1982. His dissertation was titled, "The Design of the Laboratory Network DISNET." In 2014 CSU recognized Gemperline as a dis...
3
Analytical Chemistry
E–Z configuration, or the E–Z convention, is the IUPAC preferred method of describing the absolute stereochemistry of double bonds in organic chemistry. It is an extension of cis–trans isomer notation (which only describes relative stereochemistry) that can be used to describe double bonds having two, three or fo...
4
Stereochemistry
The following peptides were synthesized using this method by 1949: <br/> * -Ala-Gly * -Tyr-Gly * -Tyr-Tyr * -Ala--Ala-Gly * -di-Ala--cystinyl-di-Gly * -Ala--Tyr-Gly * -Ala--Tyr-Gly-Gly * -Ala--Ala-L-Tyr-Gly-Gly * -Tyr--Tyr--Tyr * -Cystinyl-di-Gly
1
Biochemistry
Microbial cells or biomass is sometimes the intended product of fermentation. Examples include single cell protein, bakers yeast, lactobacillus, E. coli, and others. In the case of single-cell protein, algae is grown in large open ponds which allow photosynthesis to occur. If the biomass is to be used for inoculation o...
1
Biochemistry
Kortüm was a physical chemist who had a broad range of interests, and published prolifically. His research covered many aspects of light scattering. He began to pull together what was known in various fields into an understanding of how “reflectance spectroscopy” worked. In 1969, the English translation of his book ...
7
Physical Chemistry
A cyclopentadienyl complex is a coordination complex of a metal and cyclopentadienyl groups (, abbreviated as Cp). Cyclopentadienyl ligands almost invariably bind to metals as a pentahapto (η-) bonding mode. The metal–cyclopentadienyl interaction is typically drawn as a single line from the metal center to the center ...
0
Organic Chemistry
A set of empirical rules relating the protein structure to the pK values of ionizable residues have been developed by Li, Robertson, and Jensen. These rules form the basis for the [https://biolib.com/bio-utils/propka/ web-accessible] program called PROPKA for rapid predictions of pK values. A recent empirical pK predic...
7
Physical Chemistry
The most direct method for measuring atmospheric carbon dioxide concentrations for periods before instrumental sampling is to measure bubbles of air (fluid or gas inclusions) trapped in the Antarctic or Greenland ice sheets. The most widely accepted of such studies come from a variety of Antarctic cores and indicate th...
2
Environmental Chemistry
Quinaldine red is an indicator that turns from colorless to red between a pH of 1.0–2.2. The image below shows what color quinaldine red would appear as in a given pH. It is a cationic molecule that undergoes oxidation at different levels of pH. The rate of oxidation of Quinaldine red is in the first order with respect...
3
Analytical Chemistry
The rate of electromagnetic radiation emitted at a given frequency is proportional to the amount of absorption that it would experience by the source, a property known as reciprocity. Thus, a surface that absorbs more red light thermally radiates more red light. This principle applies to all properties of the wave, inc...
7
Physical Chemistry
Poly(ADP-ribose)polymerases (PARPs) are found mostly in eukaryotes and catalyze the transfer of multiple ADP-ribose molecules to target proteins. As with mono(ADP-ribosyl)ation, the source of ADP-ribose is NAD. PARPs use a catalytic triad of His-Tyr-Glu to facilitate binding of NAD and positioning of the end of the exi...
1
Biochemistry
Schoell has made many contributions to geochemistry with emphasis on the applications of stable isotope analysis. The results of Schoells work have included identifying the pathways of formation that distinguish methane of biogenic origin from that of thermogenic origin using stable isotope analysis. In the paper, "Bio...
9
Geochemistry
Consider a typical balanced chemical reaction: The lowercase letters (, , , and ) represent stoichiometric coefficients, while the capital letters represent the reactants ( and ) and the products ( and ). According to IUPAC's Gold Book definition the reaction rate for a chemical reaction occurring in a closed system a...
7
Physical Chemistry
It is a less explosive alternative to diazomethane for the methylation of carboxylic acids. It also reacts with alcohols to give methyl ethers, where diazomethane may not. It has also been employed widely in tandem with GC-MS for the analysis of various carboxylic compounds which are ubiquitous in nature. The fact that...
0
Organic Chemistry
In 1821, the German physicist Thomas Johann Seebeck discovered that a magnetic needle held near a circuit made up of two dissimilar metals got deflected when one of the dissimilar metal junctions was heated. At the time, Seebeck referred to this consequence as thermo-magnetism. The magnetic field he observed was later ...
8
Metallurgy
There is no evidence to show that any of these foods have a negative calorific impact. Foods claimed to be negative in calories are mostly low-calorie fruits and vegetables such as celery, grapefruit, orange, lemon, lime, apple, lettuce, broccoli, and cabbage. However, celery has a thermic effect of around 8%, much les...
1
Biochemistry
Bis(trimethylsilyl)peroxide (sometimes abbreviated as BTSP) is an organosilicon compound with the formula ((CH)SiO). It is a colorless liquid that is soluble in organic solvents so long as they lack acidic groups. The compound represents an aprotic analogue of hydrogen peroxide and as such it is used for certain sens...
0
Organic Chemistry
Shamoo was born and raised in Baghdad, Iraq. He is an ethnic Iraqi. He attended the University of Baghdad and graduated with a degree in physics in 1962. In 1966, he earned a Master's of Science in physics from the University of Louisville. Four years later, in 1970, he finished his Ph.D. in the program in Biology at t...
1
Biochemistry
An increasing offset between the optical phase and the maximum of the wave envelope of an optical pulse can be seen on the right. Each line is displaced from a harmonic of the repetition rate by the carrier–envelope offset frequency. The carrier–envelope offset frequency is the rate at which the peak of the carrier f...
7
Physical Chemistry
In 2020, a large harmful algal bloom closed beaches in Poland and Finland, brought on by a combination of fertilizer runoff and extreme heat, posing a risk to flounder and mussel beds. This is seen by the Baltic Sea Action Group as a threat to biodiversity and regional fishing stocks.
3
Analytical Chemistry
The acentric factor is a conceptual number introduced by Kenneth Pitzer in 1955, proven to be useful in the description of fluids. It has become a standard for the phase characterization of single & pure components, along with other state description parameters such as molecular weight, critical temperature, critical ...
7
Physical Chemistry
Continuous casting is a refinement of the casting process for the continuous, high-volume production of metal sections with a constant cross-section. Its primarily used to produce a semi-finished products for further processing. Molten metal is poured into an open-ended, water-cooled mold, which allows a skin' of soli...
8
Metallurgy
2A peptides are a class of 18–22 aa-long peptides, which can induce ribosomal skipping during translation of a protein in a biological cell. These peptides share a core sequence motif of , and are found in a wide range of viral families. 2A peptides can be introduced artificially to help generate polyproteins from a si...
1
Biochemistry
There may be some leakage of the electrons transferred in the respiratory chain to form reactive oxygen species. This was thought to result in significant oxidative stress in the mitochondria with high mutation rates of mitochondrial DNA. Hypothesized links between aging and oxidative stress are not new and were propos...
1
Biochemistry
The Public Analyst runs a laboratory which will: * Analyse food: ** for composition: many foods have legally defined, customary or expected compositions ** for additives: which must be legally permitted and within prescribed concentrations ** for contamination: chemical, microbiological ** to assess the accuracy of la...
2
Environmental Chemistry
Perovskites may be structured in layers, with the structure separated by thin sheets of intrusive material. Different forms of intrusions, based on the chemical makeup of the intrusion, are defined as: * Aurivillius phase: the intruding layer is composed of a [] ion, occurring every n layers, leading to an overall ch...
3
Analytical Chemistry
In the early 1970s, computer technology enabled on-site data processing, some real-time analysis, and even graphical displays of metabolic variables, such as O, CO, and air-flow, thereby encouraging academic institutions to test accuracy and precision in new ways. A few years later in the decade, battery-operated syste...
1
Biochemistry
MDA can generate 1&ndash;2 µg of DNA from single cell with genome coverage of up to 99%. Products also have lower error rate and larger sizes compared to PCR based Taq amplification. General work flow of MDA: # Sample preparation: Samples are collected and diluted in the appropriate reaction buffer (Ca and Mg free). Ce...
1
Biochemistry
The AMNet consists of approximately 15 sites across the U.S. and Canada. The function of these sites is to measure ambient air concentrations of gaseous oxidized mercury (GOM), particulate bound mercury (PBM), and gaseous elemental mercury (GEM). This network works to monitor and report atmospheric mercury that causes ...
2
Environmental Chemistry
Athletes may adopt gene therapy technologies to improve their performance. Gene doping is not known to occur, but multiple gene therapies may have such effects. Kayser et al. argue that gene doping could level the playing field if all athletes receive equal access. Critics claim that any therapeutic intervention for no...
1
Biochemistry
As it was previously mentioned, L-Photo-Methionine can be used to study protein-protein interactions with the proteins in their native environment. How this is possible is how the amino acid behaves when exposed to UV light. To prove that first the synthesis works, a radioactive carbon (C) as added under its own synthe...
5
Photochemistry
Various composite coatings were analyzed on filter paper in an experiment done by Wang et al. The ability to separate homogenous liquid solutions based on varying surface tensions has great practical use. Creating superhydrophobic and superoleophilic filter paper was achieved by treating the surface of commercially ava...
7
Physical Chemistry
Characterization and quantification of the transcriptome in a given "dead" tissue can identify genetic assets, which can be used to determine the regulatory mechanisms and set networks of gene expression. The techniques commonly used for simultaneously measuring the concentration of a large number of different types of...
1
Biochemistry
Huntington's disease is a disease characterized by minor coordination problems, jerking eye movements, and uncontrollable movement of peripheral limbs. Symptoms generally occur at the age of 40, and are often accompanied by depression and psychosis. The disease is caused by a mutation in the Huntingtin gene, on chromos...
1
Biochemistry
The introduction of amalgamation to silver refining in the Americas not only ended the mid-sixteenth century crisis in silver production, it also inaugurated a rapid expansion of silver production in New Spain and Peru as miners could now profitably mine lower-grade ores. In addition, places that were rich in ore but t...
8
Metallurgy
These proteins are synthesized in the cell bodies of the supraoptic and paraventricular regions of the hypothalamus. The disulfide-rich neurophysin protein is suggested to be congruent with the synthesis of insulin in which a precursor molecule of higher molecular weight is proteolytically cleaved and forms disulfide ...
1
Biochemistry
As a reference, molten sodium chloride, table salt has a melting point (m.p.) of 801 °C (1474 °F). A variety of eutectic mixtures have been developed with lower melting points:
8
Metallurgy
The name NANOG derives from Tír na nÓg (Irish for "Land of the Young"), a name given to the Celtic Otherworld in Irish and Scottish mythology.
1
Biochemistry
A polyoxyanion is a polymeric oxyanion in which multiple oxyanion monomers, usually regarded as polyhedra, are joined by sharing corners or edges. When two corners of a polyhedron are shared the resulting structure may be a chain or a ring. Short chains occur, for example, in polyphosphates. Inosilicates, such as pyro...
7
Physical Chemistry
Oxidative phosphorylation works by using energy-releasing chemical reactions to drive energy-requiring reactions. The two sets of reactions are said to be coupled. This means one cannot occur without the other. The chain of redox reactions driving the flow of electrons through the electron transport chain, from electro...
1
Biochemistry
Femtochemistry has been used to show the time-resolved electronic stages of bromine dissociation. When dissociated by a 400 nm laser pulse, electrons completely localize onto individual atoms after 140 fs, with Br atoms separated by 6.0 Å after 160 fs.
7
Physical Chemistry
Difference density maps are usually calculated using Fourier coefficients which are the differences between the observed structure factor amplitudes from the X-ray diffraction experiment and the calculated structure factor amplitudes from the current model, using the phase from the model for both terms (since no phases...
3
Analytical Chemistry
In the field of environmental science, adsorption is involved in many parts of technologies that can eliminate pollutants and governs the concentration of chemicals in soils and/or atmosphere. When studying pollutant degradation or the geochemical process, the pzc value related to adsorption has been examined. For exam...
7
Physical Chemistry
Other phenomena in which large effects may be achieved faster than small effects are: * Latent heat: Turning ice to water takes the same amount of energy as heating water from to . * Leidenfrost effect: Lower temperature boilers can sometimes vaporize water faster than higher temperature boilers.
7
Physical Chemistry
Many different illnesses can cause an increase in metabolic activity as the body combats illness and disease in order to heal itself. Hypermetabolism is a common symptom of various pathologies. Some of the most prevalent diseases characterized by hypermetabolism are listed below. * Hyperthyroidism: Manifestation: An ov...
1
Biochemistry
Paucimannosylation has been extensively studied and documented in insects, nematodes and plants over the past decades. The paucimannosidic proteins are constitutively and broadly expressed across tissues in these organisms under normal physiology. It is widely recognised that paucimannosylation is a central component o...
1
Biochemistry
When the electrons in the atom are excited, for example by being heated, the additional energy pushes the electrons to higher energy orbitals. When the electrons fall back down and leave the excited state, energy is re-emitted in the form of a photon. The wavelength (or equivalently, frequency) of the photon is determi...
7
Physical Chemistry
Dunne completed a Bachelor of Science and Master of Engineering degree from the Department of Mechanical Engineering, University of Bristol by 1989, and moved to the Department of Mechanical and Process Engineering, University of Sheffield, for a Doctor of Philosophy in Computer Aided Modelling of Creep-cyclic Plastici...
8
Metallurgy
The expectation value of a quantum mechanical observable represents the average value which would be measured after performing repeated measurements on an ensemble of identically prepared quantum states. Therefore, while we have been examining this expectation value as the principal object of interest, it is not clear ...
7
Physical Chemistry
The word ion was coined from neuter present participle of Greek ἰέναι (ienai), meaning "to go". A cation is something that moves down (, kato, meaning "down") and an anion is something that moves up (, ano, meaning "up"). They are so called because ions move toward the electrode of opposite charge. This term was intro...
7
Physical Chemistry
An oil formulation consists of the base or stock oil and oil additives. Most oil formulations contain basic additives and detergents, designed to react with and neutralise acids, preventing damage to engine parts, including corrosion of metal surfaces.
3
Analytical Chemistry
A mass spectrometer is typically utilized in one of two ways: full scan or selective ion monitoring (SIM). The typical GC–MS instrument is capable of performing both functions either individually or concomitantly, depending on the setup of the particular instrument. The primary goal of instrument analysis is to quanti...
3
Analytical Chemistry
In 1962 racemic galanthamine and epi-galanthamine were prepared by organic reduction of racemic narwedine by D. H. R. Barton. Narwedine is the related enone (galanthamine the allyl alcohol) obtained in an oxidative coupling. Chemical yield: 1.4%. In addition they isolated (−)-narwardine by chiral resolution from a mixt...
0
Organic Chemistry
In forensic science, evidence can become contaminated. Contamination of fingerprints, hair, skin, or DNA—from first responders or from sources not related to the ongoing investigation, such as family members or friends of the victim who are not suspects—can lead to wrongful convictions, mistrials, or dismissal of evide...
9
Geochemistry
The number of two-component systems present in a bacterial genome is highly correlated with genome size as well as ecological niche; bacteria that occupy niches with frequent environmental fluctuations possess more histidine kinases and response regulators. New two-component systems may arise by gene duplication or by ...
1
Biochemistry
Exemestane is an oral steroidal aromatase inhibitor that is used in ER-positive breast cancer in addition to surgery and/or radiation in post-menopausal women. The main source of estrogen is the ovaries in premenopausal women, while in post-menopausal women most of the body's estrogen is produced via the conversion of ...
4
Stereochemistry
Asemota has a long history of international consultancy in matters of food security and biotechnology. She was an international technical expert for the European Union (1994-1995), and served the United Nations Technical Cooperation among Developing Countries (TCDC) Programmes as International Technical Cooperation Pro...
1
Biochemistry
The symmetry-imposed barrier heights of group transfer reactions can also be analyzed using correlation diagrams. A model reaction is the transfer of a pair of hydrogen atoms from ethane to perdeuterioethylene shown to the right. The only conserved symmetry element in this reaction is the mirror plane through the cente...
7
Physical Chemistry