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Reporter genes can be used to assay for the expression of a gene of interest that is normally difficult to quantitatively assay. Reporter genes can produce a protein that has little obvious or immediate effect on the cell culture or organism. They are ideally not present in the native genome to be able to isolate reporter gene expression as a result of the gene of interest's expression.
To activate reporter genes, they can be expressed constitutively, where they are directly attached to the gene of interest to create a gene fusion. This method is an example of using cis-acting elements where the two genes are under the same promoter elements and are transcribed into a single messenger RNA molecule. The mRNA is then translated into protein. It is important that both proteins be able to properly fold into their active conformations and interact with their substrates despite being fused. In building the DNA construct, a segment of DNA coding for a flexible polypeptide linker region is usually included so that the reporter and the gene product will only minimally interfere with one another. Reporter genes can also be expressed by induction during growth. In these cases, trans-acting elements, such as transcription factors are used to express the reporter gene.
Reporter gene assay have been increasingly used in high throughput screening (HTS) to identify small molecule inhibitors and activators of protein targets and pathways for drug discovery and chemical biology. Because the reporter enzymes themselves (e.g. firefly luciferase) can be direct targets of small molecules and confound the interpretation of HTS data, novel coincidence reporter designs incorporating artifact suppression have been developed. | 1 | Applied and Interdisciplinary Chemistry |
This method is well suited to irregular rock samples (e.g. those found in drill cuttings) and is typically used to understand the relationship between capillary pressure and the porous structure of the sample. In this method, the pores of the sample rock are evacuated, followed by mercury filling the pores with increasing pressure. Meanwhile, the volume of mercury at each given pressure is recorded and given as a pore size distribution, or converted to relevant oil/gas data. One pitfall to this method is that it does not account for fluid-surface interactions. However, the entire process of injecting mercury and collecting data occurs rapidly in comparison to other methods. | 1 | Applied and Interdisciplinary Chemistry |
Some of the earliest, published studies on sweat composition date back to the 19th century. Further studies in the 20th century began to solidify understanding of the physiology and pharmacology of the eccrine sweat gland. In-vivo and in-vitro studies from this time period, and even those continuing today, have identified numerous structural nuances and new molecules present within sweat. The first commercially adopted use for sweat diagnostics included testing of sodium and chloride levels in children for the diagnosis of cystic fibrosis. Today, one of the most popular devices for this testing is the Macroduct Sweat Collection System from ELITechGroup. | 1 | Applied and Interdisciplinary Chemistry |
Another example of non-Newtonian fluid flow is chilled caramel ice cream topping (so long as it incorporates hydrocolloids such as carrageenan and gellan gum). The sudden application of force—by stabbing the surface with a finger, for example, or rapidly inverting the container holding it—causes the fluid to behave like a solid rather than a liquid. This is the "shear thickening" property of this non-Newtonian fluid. More gentle treatment, such as slowly inserting a spoon, will leave it in its liquid state. Trying to jerk the spoon back out again, however, will trigger the return of the temporary solid state. | 1 | Applied and Interdisciplinary Chemistry |
The EFI is developing an integrated sequence-structure based strategy for functional assignment by predicting the substrate specificities of unknown members of mechanistically diverse enzyme superfamilies. The approach leverages conserved features within a given superfamily such as known chemistry, identity of active site functional groups, and composition of specificity-determining residues, motifs, or structures to predict function but relies on multidisciplinary expertise to streamline, refine, and test the predictions. The integrated sequence-strategy under development will be generally applicable to deciphering the ligand specificities of any functionally unknown protein. | 1 | Applied and Interdisciplinary Chemistry |
When an anomeric center is involved in a glycosidic bond (as is common in nature) then one can distinguish between α- and β-glycosidic bonds by the relative stereochemistry of the anomeric position and the stereocenter furthest from C1 in the saccharide.
Pharmacologists often join substances to glucuronic acid via glycosidic bonds in order to increase their water solubility; this is known as glucuronidation. Many other glycosides have important physiological functions. | 0 | Theoretical and Fundamental Chemistry |
*The reaction has been attempted in the microwave, improving yields with the α-glucopyranoside to 88% and reducing the reaction time significantly to 14 minutes.
*The original paper by Tipson and Cohen also used acyclic sugars to illustrate the utility of the reaction. Thus the reaction is not limited to cyclic carbohydrate derivatives.
*Sulphonoxy groups such as methanesulfonyl and toluenesulfonyl were both used, however it was found that substrates with toluenesulfonyl groups gave higher yields and lower reaction times. | 0 | Theoretical and Fundamental Chemistry |
Stereoscopic spectroscopy is a type of imaging spectroscopy that can extract a few spectral parameters over a complete image plane simultaneously. A stereoscopic spectrograph is similar to a normal spectrograph except that (A) it has no slit, and (B) multiple spectral orders (often including the non-dispersed zero order) are collected simultaneously. The individual images are blurred by the spectral information present in the original data. The images are recombined using stereoscopic algorithms similar to those used to find ground feature altitudes from parallax in aerial photography.
Stereoscopic spectroscopy is a special case of the more general field of tomographic spectroscopy. Both types of imaging use an analogy between the data space of imaging spectrographs and the conventional 3-space of the physical world. Each spectral order in the instrument produces an image plane analogous to the view from a camera with a particular look angle through the data space, and recombining the views allows recovery of (some aspects of) the spectrum at every location in the image. | 0 | Theoretical and Fundamental Chemistry |
An aircraft's static pressure system is the key input to its altimeter and, along with the pitot pressure system, also drives the airspeed indicator.
The static pressure system is open to the aircrafts exterior through a small opening called the static port, which allows sensing the ambient atmospheric pressure at the altitude at which the aircraft is flying. In flight, the air pressure varies slightly at different positions around the aircrafts exterior, so designers must select the static ports locations carefully. Wherever they are located, the air pressure that the ports observe will generally be affected by the aircrafts instantaneous angle of attack. The difference between that observed pressure and the actual atmospheric pressure (at altitude) causes a small position error in the instruments indicated altitude and airspeed. A designers objective in locating the static port is to minimize the resulting position error across the aircraft's operating range of weight and airspeed.
Many authors describe the atmospheric pressure at the altitude at which the aircraft is flying as the freestream static pressure. At least one author takes a different approach in order to avoid a need for the expression freestream static pressure. Gracey has written "The static pressure is the atmospheric pressure at the flight level of the aircraft". Gracey then refers to the air pressure at any point close to the aircraft as the local static pressure. | 1 | Applied and Interdisciplinary Chemistry |
Recombinant DNA (rDNA), or molecular cloning, is the process by which a single gene, or segment of DNA, is isolated and amplified. Recombinant DNA is also known as in vitro recombination. A cloning vector is a DNA molecule that carries foreign DNA into a host cell, where it replicates, producing many copies of itself along with the foreign DNA. There are many types of cloning vectors such as plasmids and phages. In order to carry out recombination between vector and the foreign DNA, it is necessary the vector and DNA to be cloned by digestion, ligase the foreign DNA into the vector with the enzyme DNA ligase. And DNA is inserted by introducing the DNA into bacteria cells by transformation. | 1 | Applied and Interdisciplinary Chemistry |
Members of the SOBER1 family are considered closely related to acyl-protein thioesterases, judged by their protein structure. However, a change in their amino acid sequence renders SOBER1's biochemical properties into a deacetylase; in particular the hydrophobic tunnel, which is found in acyl-protein thioesterases, is impaired by additional amino acids in the lid structure of SOBER1, creating a new surface for binding of the acetyl group. | 0 | Theoretical and Fundamental Chemistry |
Many ligands are known to form homoleptic and mixed ligand complexes that are analogous to the metal carbonyls. | 0 | Theoretical and Fundamental Chemistry |
Temporal Analysis of Products (TAP), (TAP-2), (TAP-3) is an experimental technique for studying
the kinetics of physico-chemical interactions
between gases and complex solid materials, primarily heterogeneous catalysts.
The TAP methodology is based on short pulse-response experiments at low background pressure (10-10 Pa),
which are used to probe different steps in a catalytic process on the surface of a
porous material including diffusion, adsorption,
surface reactions, and desorption. | 0 | Theoretical and Fundamental Chemistry |
There are a number of different distinct classes of protein mimetics.
*Antibody mimetic - Molecules that mimic antigen binding activity of antibodies
*Peptidomimetic - Small protein-like chains designed to mimic larger peptide.
*Phosphomimetics - An amino acid substitution or modification which mimic the effect of protein phosphorylation. | 1 | Applied and Interdisciplinary Chemistry |
LASiS has some limitations in the size control of NMNp, which can be overcome by laser treatments of NMNp. Other cons of LASiS include: the slow rate of NPs production, high consumption of energy, laser equipment cost, and decreased ablation efficiency with longer usage of the laser within a session. Other pros of LASiS include: minimal waste production, minimal manual operation, and refined size control of nanoparticles. | 0 | Theoretical and Fundamental Chemistry |
The addition of surfactants does not always have a positive effect on all properties. The water resistance of the coating can be decreased with surfactant addition since surfactants can be very water-soluble and will easily wash out of a coating. This problem of moisture resistance is particularly prevalent problem for art conservation, as well as problems with adhesion, loss of optical clarity, and dirt pickup caused by polyether surfactants in contemporary acrylic emulsion used in artworks bearing acrylic coats. While the type and amount of surfactant determine what properties will be affected, other chemicals in a paint can alter the overall effect the surfactants may have on the paint. Elasticity has been found to either increase or decrease in latex paints depending on the amount of TiO present. | 0 | Theoretical and Fundamental Chemistry |
EPANET hydraulics engine computes headlosses along the pipes by using one of the three formulas:
*Hazen-Williams formula: used to model full flow conditions under simplified conditions (turbulent flow, temperature around 60 degrees Fahrenheit, and viscosity similar to water) https://www.epa.gov/water-research/epanet
*Darcy-Weisbach formula: used to model pressurized flow under a broader range of hydraulic conditions
*Chezy-Manning formula: used to model pressurized flow by using Chezys roughness coefficients for Mannings equation
Since the pipe segment headloss equation is used within the network solver, the formula above is selected for the entire model. | 1 | Applied and Interdisciplinary Chemistry |
* Tooth organoid (TO) (see also tooth regeneration)
* Thyroid organoid
* Thymic organoid
::Thymic organoids recapitulate at least partly the architecture and stem-cell niche functionality of the thymus, which is a lymphoid organ where T cells mature. Thymic organoids have been generated through the seeding of thymic stromal cells in 3-dimensional culture. Thymic organoids seem to successfully recapitulate the thymus' function, as co-culturing human hematopoietic or bone marrow stem cells with mouse thymic organoids resulted in the production of T-cells.
* Testicular organoid
*Prostate organoid
* Hepatic organoid. A recent study showed the usefulness of the technology for identifying novel medication for the treatment of hepatitis E as it allows to allows to recapitulate the entire viral life cycle.
* Pancreatic organoid
::Recent advances in cell repellent microtiter plates has allowed rapid, cost-effective screening of large small molecule drug like libraries against 3D models of pancreas cancer. These models are consistent in phenotype and expression profiles with those found in the lab of Dr. David Tuveson.
* Epithelial organoid
* Lung organoid
* Kidney organoid
* Gastruloid (embryonic organoid) – Generates all embryonic axes and fully implements the collinear Hox gene expression patterns along the anteroposterior axis.
* Blastoid (blastocyst-like organoid)
* Endometrial organoid
* Cardiac organoid – In 2018 hollow cardiac organoids were made to beat, and to respond to stimuli to beat faster or slower.
* Retinal organoid
* Breast cancer organoid
* Colorectal cancer organoid
* Glioblastoma organoid
* Neuroendocrine tumor organoid
* Myelinoid (Myelin organoid)
* Blood-brain barrier (BBB) organoid | 1 | Applied and Interdisciplinary Chemistry |
Quantitative studies of enzymatic reactions often found that the acceleration of chemical reaction speed cannot be fully explained by existing theories like the approximation, acid/base catalysis and electrophile/nucleophile catalysis. And there is an obvious paradox: in reversible enzymatic reaction if the active site perfectly fits the substrates then the backward reaction will be slowed since products cannot fit perfectly into the active site. So conformational distortion was introduced and argues that both active site and substrate can undergo conformational changes to fit with each other all the time. | 1 | Applied and Interdisciplinary Chemistry |
Ordinarily, the probability of the triple-alpha process is extremely small. However, the beryllium-8 ground state has almost exactly the energy of two alpha particles. In the second step, Be + He has almost exactly the energy of an excited state of C. This resonance greatly increases the probability that an incoming alpha particle will combine with beryllium-8 to form carbon. The existence of this resonance was predicted by Fred Hoyle before its actual observation, based on the physical necessity for it to exist, in order for carbon to be formed in stars. The prediction and then discovery of this energy resonance and process gave very significant support to Hoyle's hypothesis of stellar nucleosynthesis, which posited that all chemical elements had originally been formed from hydrogen, the true primordial substance. The anthropic principle has been cited to explain the fact that nuclear resonances are sensitively arranged to create large amounts of carbon and oxygen in the universe. | 0 | Theoretical and Fundamental Chemistry |
George Simmons Hammond was born on May 22, 1921, in Auburn, Maine. Growing up in Auburn his family were charged with the operation of the neighborhood dairy farm on Hardscrapple Road. His father died when Hammond was thirteen. He was the oldest of seven children and was raised by a single mother. From an early age Hammond was charged with running the day-to-day operations of the dairy farm with his mother and older siblings. Hammond's parents were college graduates, but disliked the local schools in Auburn. As a result, he was homeschooled until the sixth grade. Afterwards, he was educated at various Auburn public schools before graduating in 1938. After graduating he took a gap year to continue operating his dairy farm. After his educational hiatus he applied to and was accepted into Bates College, in Lewiston, Maine. He graduated with a Bachelors of Science in chemistry magna cum laude and Phi Beta Kappa in January 1943. | 0 | Theoretical and Fundamental Chemistry |
She worked as a postdoctoral researcher at Bell Laboratories for a year afterward before joining the University of Texas at Austins Chemical Engineering Department. During her time at Bell Labs, Loo, along with Julia Hsu, accidentally uncovered duplicated figures in two papers by Jan Hendrik Schön, the first of many instances of academic fraud from the researcher. In 2004, she was included by MIT Technology Review' on its TR35 list of under-35-year-old innovators for her invention of nanotransfer printing, a technique for printing nanoscale patterns onto plastic surfaces. This technique allows for the creation of organic electronic devices by printing electrical circuit components onto plastic surfaces.
In 2007, Loo joined the faculty of Princetons Chemical and Biological Engineering Department, where, , she is the Theodora D. 78 and William H. Walton III '74 Professor in Engineering. Her research concerns the periodic structures of block polymers, organic semiconductors, and patterning techniques for plastic electronics.
Loo launched the Princeton E-ffiliates Partnership (E-ffiliates) in 2012.
In 2016 she was appointed director of Andlinger Center for Energy and the Environment.
Loos research group studies solution-processable organic semiconductors and conductors. She also researches soft lithography. Using derivatives of Hexabenzocoronene Loos group developed transparent near-UV solar cells for smart windows, which also contain electrochromic polymers that control the window tint. | 1 | Applied and Interdisciplinary Chemistry |
;Kinetic Sand
* A toy trademarked and produced by Spin Master Ltd. Kinetic Sand looks like regular wet sand but is available in different colors. It can be molded into any desired shape. It is 98% ultra-fine grain sand mixed with 2% dimethicone (polydimethylsiloxane), and coated with olive oil. Because of its oil coating, the sand never dries out. It mimics the physical properties of wet sand.
;Aqua Sand
* Similar properties as above. | 1 | Applied and Interdisciplinary Chemistry |
Green fluorescent protein may be used as a reporter gene.
For example, GFP can be used as a reporter for environmental toxicity levels. This protein has been shown to be an effective way to measure the toxicity levels of various chemicals including ethanol, p-formaldehyde, phenol, triclosan, and paraben. GFP is great as a reporter protein because it has no effect on the host when introduced to the host's cellular environment. Due to this ability, no external visualization stain, ATP, or cofactors are needed. With regards to pollutant levels, the fluorescence was measured in order to gauge the effect that the pollutants have on the host cell. The cellular density of the host cell was also measured. Results from the study conducted by Song, Kim, & Seo (2016) showed that there was a decrease in both fluorescence and cellular density as pollutant levels increased. This was indicative of the fact that cellular activity had decreased. More research into this specific application in order to determine the mechanism by which GFP acts as a pollutant marker. Similar results have been observed in zebrafish because zebrafish that were injected with GFP were approximately twenty times more susceptible to recognize cellular stresses than zebrafish that were not injected with GFP. | 1 | Applied and Interdisciplinary Chemistry |
As stated above, a chair flip is a ring inversion specifically of cyclohexane (and its derivatives) from one chair conformer to another, often to reduce steric strain. The term, "flip" is misleading, because the direction of each carbon remains the same; what changes is the orientation. A conformation is a unique structural arrangement of atoms, in particular one achieved through the rotation of single bonds. A conformer is a conformational isomer, a blend of the two words. | 0 | Theoretical and Fundamental Chemistry |
The use of EAFs allows steel to be made from a 100% scrap metal feedstock. This greatly reduces the energy required to make steel when compared with primary steelmaking from ores.
Another benefit is flexibility: while blast furnaces cannot vary their production by much and can remain in operation for years at a time, EAFs can be rapidly started and stopped, allowing the steel mill to vary production according to demand.
Although steelmaking arc furnaces generally use scrap steel as their primary feedstock, if hot metal from a blast furnace or direct-reduced iron is available economically, these can also be used as furnace feed.
As EAFs require large amounts of electrical power, many companies schedule their operations to take advantage of off-peak electricity pricing.
A typical steelmaking arc furnace is the source of steel for a mini-mill, which may make bars or strip product. Mini-mills can be sited relatively near the markets for steel products, so the transport requirements are less than for an integrated mill, which would commonly be sited near a harbor for better access to shipping.
Electric arc furnace steelmaking results in lower carbon dioxide emissions of around 0.6 ton CO per ton of steel produced, which is significantly lower than the conventional production route via blast furnaces and the basic oxygen furnace. | 1 | Applied and Interdisciplinary Chemistry |
Selecting the type of head group depends on the application of the SAM. Typically, head groups are connected to a molecular chain in which the terminal end can be functionalized (i.e. adding –OH, –NH2, –COOH, or –SH groups) to vary the wetting and interfacial properties. An appropriate substrate is chosen to react with the head group. Substrates can be planar surfaces, such as silicon and metals, or curved surfaces, such as nanoparticles. Alkanethiols are the most commonly used molecules for SAMs. Alkanethiols are molecules with an alkyl chain, (C-C)ⁿ chain, as the back bone, a tail group, and a S-H head group. Other types of interesting molecules include aromatic thiols, of interest in molecular electronics, in which the alkane chain is (partly) replaced by aromatic rings. An example is the dithiol 1,4-Benzenedimethanethiol (SHCHCHCHSH)). Interest in such dithiols stems from the possibility of linking the two sulfur ends to metallic contacts, which was first used in molecular conduction measurements. Thiols are frequently used on noble metal substrates because of the strong affinity of sulfur for these metals. The sulfur gold interaction is semi-covalent and has a strength of approximately 45 kcal/mol. In addition, gold is an inert and biocompatible material that is easy to acquire. It is also easy to pattern via lithography, a useful feature for applications in nanoelectromechanical systems (NEMS). Additionally, it can withstand harsh chemical cleaning treatments. Recently other chalcogenide SAMs: selenides and tellurides have attracted attention in a search for different bonding characteristics to substrates affecting the SAM characteristics and which could be of interest in some applications such as molecular electronics. Silanes are generally used on nonmetallic oxide surfaces; however monolayers formed from covalent bonds between silicon and carbon or oxygen cannot be considered self assembled because they do not form reversibly. Self-assembled monolayers of thiolates on noble metals are a special case because the metal-metal bonds become reversible after the formation of the thiolate-metal complex. This reversibility is what gives rise to vacancy islands and it is why SAMs of alkanethiolates can be thermally desorbed and undergo exchange with free thiols. | 0 | Theoretical and Fundamental Chemistry |
At the interface of a vapor and a liquid/solid, the gas interaction with the liquid/solid dominates the gas behavior, and the gas is, very locally, not in equilibrium. This region, several mean free path lengths thick, is called the Knudsen layer. | 1 | Applied and Interdisciplinary Chemistry |
Beyond the most common perovskite symmetries (cubic, tetragonal, orthorhombic), a more precise determination leads to a total of 23 different structure types that can be found. These 23 structure can be categorized into 4 different so-called tilt systems that are denoted by their respective Glazer notation.
The notation consists of a letter a/b/c, which describes the rotation around a Cartesian axis and a superscript +/—/0 to denote the rotation with respect to the adjacent layer. A “+” denotes that the rotation of two adjacent layers points in the same direction, whereas a “—” denotes that adjacent layers are rotated in opposite directions. Common examples are aaa, aaa and aaa which are visualized here. | 0 | Theoretical and Fundamental Chemistry |
A Lot (formerly Loth) was an old unit of measurement for the relative fineness to gross weight in metallurgy and especially in coinage until the 19th century. A Lot was thus a proportion of the precious metal content in a piece of metal. It was used in the four main monetary systems of Germany: Austrian, South German, North German and Hamburg.
The lot was defined as the sixteenth part of a Mark. For example, in silver, the total weight was divided into 16 (proportional) Lots until about 1857, according to which a "12-Lot" silver alloy (750 silver) contained 12/16 = or 75% by weight of silver and 25% of another metal (usually copper). A 14-Lot silver alloy (), on the other hand, corresponded to 875 silver. For refinement, a Lot was further divided into 18 grains. Thus 14 Lots, 4 grains fine then correspond to a fineness of 888.89 ‰ = (14 + 4 / 18) / 16 = (252 + 4)/288, i.e. 256/288 grains.
The German proportional measure, the Lot, was finally replaced on 1 January 1888 in the German Empire by the proportional measure, permille (thousandths). | 1 | Applied and Interdisciplinary Chemistry |
Tris(bipyridine)ruthenium(II) chloride is the chloride salt coordination complex with the formula [Ru(bpy)]Cl. This polypyridine complex is a red crystalline salt obtained as the hexahydrate, although all of the properties of interest are in the cation [Ru(bpy)], which has received much attention because of its distinctive optical properties. The chlorides can be replaced with other anions, such as PF. | 0 | Theoretical and Fundamental Chemistry |
Combustion analysis is a method used in both organic chemistry and analytical chemistry to determine the elemental composition (more precisely empirical formula) of a pure organic compound by combusting the sample under conditions where the resulting combustion products can be quantitatively analyzed. Once the number of moles of each combustion product has been determined the empirical formula or a partial empirical formula of
the original compound can be calculated.
Applications for combustion analysis involve only the elements of carbon (C), hydrogen (H), nitrogen (N), and sulfur (S) as combustion of materials containing them convert these elements to their oxidized form (CO, HO, NO or NO, and SO) under high temperature high oxygen conditions. Notable interests for these elements involve measuring total nitrogen in food or feed to determine protein percentage, measuring sulfur in petroleum products, or measuring total organic carbon (TOC) in water. | 0 | Theoretical and Fundamental Chemistry |
It has also been used in septic shock and anaphylaxis.
Methylene blue consistently increases blood pressure in people with vasoplegic syndrome (redistributive shock), but has not been shown to improve delivery of oxygen to tissues or to decrease mortality.
Methylene blue has been used in calcium channel blocker toxicity as a rescue therapy for distributive shock unresponsive to first line agents. Evidence for its use in this circumstance is very poor and limited to a handful of case reports. | 0 | Theoretical and Fundamental Chemistry |
Some organizations publish standards for rating the lightfastness of pigments and materials. Testing is typically done by controlled exposure to sunlight, or to artificial light generated by a xenon arc lamp. Watercolors, inks, pastels, and colored pencils are particularly susceptible to fading over time, so choosing lightfast pigments is especially important in these media.
The most well known scales measuring the lightfastness are the Blue Wool Scale, Grey scale and the scale defined by ASTM (American Standard Test Measure). On the Blue Wool Scale the lightfastness is rated between 1–8. 1 being very poor and 8 being excellent lightfastness. In grey scale the lightfastness is rated between 1–5. 1 being very poor and 5 being excellent lightfastness. On ASTM scale the lightfastness is rated between I-V. I is excellent lightfastness and it corresponds to ratings 7–8 on Blue Wool Scale. V is very poor lightfastness and it corresponds to Blue Wool scale rating 1.
The actual lightfastness is dependent on the strength of the radiation of the sun, so lightfastness is relative to geographic location, season, and exposure direction. The following table is listing suggestive relations of the lightfastness ratings on different measure scales and the relation relative to time in direct sunlight and normal conditions of display: away from a window, under indirect sunlight and properly framed behind a UV protective glass. | 0 | Theoretical and Fundamental Chemistry |
The Felspathic Highlands Terrane (alternatively Feldspathic), or FHT, is composed predominantly of ancient anorthositic materials. It has low iron oxide and thorium levels. The FHT can be split into an inner and outer felspathic highlands. The outer FHT has comparatively higher levels of iron oxide and thorium. It is thought to be part of the FHT, with the differences being due to modification by ejecta from impacts in other terranes. The FHT covers 65% of the lunar surface.
Overall, 6% of the lunar surface (and hence 9% of the FHT) consists of maria within the FHT, such as Mare Moscoviense. FHT maria have on average only 2.2 ppm of thorium, which is twice as much as the lunar average but significantly less than the levels seen in the PKT maria. Outer FHT non-maria regions contain 1 ppm of thorium, and only 0.3 ppm of thorium in the inner FHT.
The inner FHT lies exclusively in the far side of the Moon, whereas the outer FHT spans both sides and is the one of two terranes on the near side of the Moon, along with the PKT. No spacecraft have landed on the inner FHT, as the only lander to the far side touched down in the South Pole-Aitken Terrane. In contrast, the outer FHT has been the subject of human landings and sample return. | 0 | Theoretical and Fundamental Chemistry |
:1969 - Richard-Zsigmondy-Stipendium, awarded by the Kolloid-Gesellschaft (Germany)
:1995 - George W. Brindley Lecture Award, The Clay Minerals Society (USA)
:1996 - Doctor honoris causa, University of Szeged (Hungary)
:1999 - Wolfgang-Ostwald-Kolloquium of the Kolloid-Gesellschaft (Germany) dedicated to the 60th birthday of G. Lagaly
:2001 - AIPEA Medal in recognition of innovative and dynamic scientific contribution to the field of Clay Sciences
:2002 - Marilyn & Sturges W. Bailey Distinguished Member Award, Clay Minerals Society (USA)
:2002 - Socio de Honor de la Sociedad Española de Arcillas (Spain)
:2004 - Wolfgang-Ostwald-Prize, awarded by the Kolloid-Gesellschaft (Germany)
:2005 - Membre d'Honneur du Groupe Français des Argiles (France)
:2006 - Ehrenmitglied der DTTG (Germany-Austria-Switzerland) | 0 | Theoretical and Fundamental Chemistry |
In the ara operon (also known as the ara or araBAD operon), arabinose acts as both an inducer and a repressor. When arabinose is present, it allosterically binds to the regulatory protein AraC, which then helps to recruit RNA polymerase for transcription. | 0 | Theoretical and Fundamental Chemistry |
Herbert Max Finlay Freundlich (28 January 1880 in Charlottenburg – 30 March 1941 in Minneapolis) was a German chemist.
His father was of German Jewish descent, and his mother ( Finlay) was from Scotland. His younger brother was Erwin Finlay Freundlich (1885–1964).
He was a department head at the Kaiser Wilhelm Institute for Physical Chemistry and Electrochemistry (now the Fritz Haber Institute) from 1919 until 1933, when the racial policies of the Nazi party demanded the dismissal of non-Aryans from senior posts. In 1934 he became a foreign member of the Royal Netherlands Academy of Arts and Sciences.
Emigrating to England, Freundlich accepted a guest professorship at University College London. Five years later, he accepted a professorship at the University of Minnesota. He died in Minneapolis two years later.
Freundlich's main works dealt with the coagulation and stability of colloidal solutions.
His most prominent student was Robert Havemann who became a well known colloid chemist of the German Democratic Republic.
His work is of continuing importance, with his 1907 paper "Über die Adsorption in Lösungen" (On adsorption in solutions) becoming highly cited at the beginning of the 21st century. This early paper was based on his habilitation thesis written in Leipzig under the guidance of Wilhelm Ostwald, and was heavily based on the work of Sten Lagergren. | 0 | Theoretical and Fundamental Chemistry |
In August 2009, scientists in Israel raised serious doubts concerning the use of DNA by law enforcement as the ultimate method of identification. In a paper published in the journal Forensic Science International: Genetics, the Israeli researchers demonstrated that it is possible to manufacture DNA in a laboratory, thus falsifying DNA evidence. The scientists fabricated saliva and blood samples, which originally contained DNA from a person other than the supposed donor of the blood and saliva.
The researchers also showed that, using a DNA database, it is possible to take information from a profile and manufacture DNA to match it, and that this can be done without access to any actual DNA from the person whose DNA they are duplicating. The synthetic DNA oligos required for the procedure are common in molecular laboratories.
The New York Times quoted the lead author, Daniel Frumkin, saying, "You can just engineer a crime scene ... any biology undergraduate could perform this". Frumkin perfected a test that can differentiate real DNA samples from fake ones. His test detects epigenetic modifications, in particular, DNA methylation. Seventy percent of the DNA in any human genome is methylated, meaning it contains methyl group modifications within a CpG dinucleotide context. Methylation at the promoter region is associated with gene silencing. The synthetic DNA lacks this epigenetic modification, which allows the test to distinguish manufactured DNA from genuine DNA.
It is unknown how many police departments, if any, currently use the test. No police lab has publicly announced that it is using the new test to verify DNA results.
Researchers at the University of Tokyo integrated an artificial DNA replication scheme with a rebuilt gene expression system and micro-compartmentalization utilizing cell-free materials alone for the first time. Multiple cycles of serial dilution were performed on a system contained in microscale water-in-oil droplets.
Chances of making DNA change on purpose
Overall, this study's artificial genomic DNA, which kept copying itself using self-encoded proteins and made its sequence better on its own, is a good starting point for making more complex artificial cells. By adding the genes needed for transcription and translation to artificial genomic DNA, it may be possible in the future to make artificial cells that can grow on their own when fed small molecules like amino acids and nucleotides. Using living organisms to make useful things, like drugs and food, would be more stable and easier to control in these artificial cells.
On July 7, 2008, the American chemical society reported that Japanese chemists have created the world's first DNA molecule comprised nearly completely of synthetic components.
A nano-particle based artificial transcription factor for gene regulation:
Nano Script is a nanoparticle-based artificial transcription factor that is supposed to replicate the structure and function of TFs. On gold nanoparticles, functional peptides and tiny molecules referred to as synthetic transcription factors, which imitate the various TF domains, were attached to create Nano Script. We show that Nano Script localizes to the nucleus and begins transcription of a reporter plasmid by an amount more than 15-fold. Moreover, Nano Script can successfully transcribe targeted genes onto endogenous DNA in a nonviral manner.
Three different fluorophores—red, green, and blue—were carefully fixed on the DNA rod surface to provide spatial information and create a nanoscale barcode. Epifluorescence and total internal reflection fluorescence microscopy reliably deciphered spatial information between fluorophores. By moving the three fluorophores on the DNA rod, this nanoscale barcode created 216 fluorescence patterns. | 1 | Applied and Interdisciplinary Chemistry |
Sibelektroterm () is a manufacturing company in Kirovsky District of Novosibirsk, Russia. It was founded in 1945. The enterprise is a developer and manufacturer of electrometallurgical equipment. | 1 | Applied and Interdisciplinary Chemistry |
The critical issue of the solar neutrino problem, that many astrophysicists interested in solar neutrinos studied and attempted to solve in late 1900s and early 2000s, is solved. In the 21st century, even without a main problem to solve, there is still unique and novel research ongoing in this field of astrophysics. | 0 | Theoretical and Fundamental Chemistry |
The quasistatic equations that describe the scattering and absorbance cross-sections for very small spherical nanoparticles are:
where is the wavenumber of the electric field, is the radius of the particle, is the relative permittivity of the dielectric medium and is the relative permittivity of the nanoparticle defined by
also known as the Drude Model for free electrons where is the plasma frequency, is the relaxation frequency of the charge carries, and is the frequency of the electromagnetic radiation. This equation is the result of solving the differential equation for a harmonic oscillator with a driving force proportional to the electric field that the particle is subjected to. For a more thorough derivation, see surface plasmon.
It logically follows that the resonance conditions for these equations is reached when the denominator is around zero such that
When this condition is fulfilled the cross-sections are at their maximum.
These cross-sections are for single, spherical particles. The equations change when particles are non-spherical, or are coupled to 1 or more other nanoparticles, such as when their geometry changes. This principle is important for several applications.
Rigorous electrodynamic analysis of plasma oscillations in a spherical metal nanoparticle of a finite size was performed in. | 0 | Theoretical and Fundamental Chemistry |
The Journal of Photochemistry and Photobiology A: Chemistry is abstracted and indexed in BIOSIS Previews, Chemical Abstracts, Chemical Citation Index, Current Contents/Physics, Chemistry & Engineering, Engineering Index, Metals Abstracts, PASCAL, Physics Abstracts, Physikalische Berichte, Polymer Contents, Science Citation Index and Scopus. According to the Journal Citation Reports, the journal has a 2019 impact factor of 3.261. | 0 | Theoretical and Fundamental Chemistry |
Heat exchange in a rotary kiln may be by conduction, convection and radiation, in descending order of efficiency. In low-temperature processes, and in the cooler parts of long kilns lacking preheaters, the kiln is often furnished with internal heat exchangers to encourage heat exchange between the gas and the feed. These may consist of scoops or "lifters" that cascade the feed through the gas stream, or may be metallic inserts that heat up in the upper part of the kiln, and impart the heat to the feed as they dip below the feed surface as the kiln rotates. The latter are favoured where lifters would cause excessive dust pick-up. The most common heat exchanger consists of chains hanging in curtains across the gas stream. | 1 | Applied and Interdisciplinary Chemistry |
The liberated catalytic subunits can then catalyze the transfer of ATP terminal phosphates to protein substrates at serine, or threonine residues. This phosphorylation usually results in a change in activity of the substrate. Since PKAs are present in a variety of cells and act on different substrates, PKA regulation and cAMP regulation are involved in many different pathways.
The mechanisms of further effects may be divided into direct protein phosphorylation and protein synthesis:
*In direct protein phosphorylation, PKA directly either increases or decreases the activity of a protein.
*In protein synthesis, PKA first directly activates CREB, which binds the cAMP response element (CRE), altering the transcription and therefore the synthesis of the protein. In general, this mechanism takes more time (hours to days). | 1 | Applied and Interdisciplinary Chemistry |
Vortices like eddies are created by instabilities in a flow. When there are instabilities within the mean flow, energy can be transferred from the mean flow to the small perturbations which can then grow. In a barotropic fluid the density is a function of only the pressure and not the temperature (in contrast to a baroclinic fluid, where the density is a function of both the pressure and temperature). This means that surfaces of constant density (isopycnals) are also surfaces of constant pressure (isobars). Barotropic instability can form in different ways. Two examples are; when there is an interaction between the fluid flow and the bathymetry or topography of the domain; when there are frontal instabilities (may also lead to baroclinic instabilities). These instabilities are not dependent on the density and might even occur when the density of the fluid is constant. Instead, most of the instabilities are caused by a shear on the flow as can be seen in Figure 1. This shear in the velocity field induces a vertical and horizontal vorticity within the flow. As a result, there is upwelling on the right of the flow and downwelling on the left. This situation might lead to a barotropic unstable flow. The eddies that form alternatingly on both sides of the flow are part of this instability.
Another way to achieve this instability is to displace the Rossby waves in the horizontal direction (see Figure 2). This leads to a transfer of kinetic energy (not potential energy) from the mean flow towards the small perturbations (the eddies). The Rayleigh–Kuo criterion states that the gradient of the absolute vorticity should change sign within the domain. In the example of the shear induced eddies on the right, this means that the second derivative of the flow in the cross-flow direction, should be zero somewhere. This happens in the centre of the eddies, where the acceleration of the flow perpendicular to the flow changes direction. | 1 | Applied and Interdisciplinary Chemistry |
Oseltamivir has a large hydrophobic side chain and the NA must undergo rearrangement to form a pocket for drug binding by rotating aminoacid E276 and bond with R224. Mutations like H274Y, R292K and N294S that affect this forming could reduce the inhibitor's efficiency. | 1 | Applied and Interdisciplinary Chemistry |
The detection of optical scattering and the gradient forces on micron sized particles was first reported in 1970 by Arthur Ashkin, a scientist working at Bell Labs. Years later, Ashkin and colleagues reported the first observation of what is now commonly referred to as an optical tweezer: a tightly focused beam of light capable of holding microscopic particles stable in three dimensions. In 2018, Ashkin was awarded the Nobel Prize in Physics for this development.
One author of this seminal 1986 paper, Steven Chu, would go on to use optical tweezing in his work on cooling and trapping neutral atoms. This research earned Chu the 1997 Nobel Prize in Physics along with Claude Cohen-Tannoudji and William D. Phillips. In an interview, Steven Chu described how Ashkin had first envisioned optical tweezing as a method for trapping atoms. Ashkin was able to trap larger particles (10 to 10,000 nanometers in diameter) but it fell to Chu to extend these techniques to the trapping of neutral atoms (0.1 nanometers in diameter) using resonant laser light and a magnetic gradient trap (cf. Magneto-optical trap).
In the late 1980s, Arthur Ashkin and Joseph M. Dziedzic demonstrated the first application of the technology to the biological sciences, using it to trap an individual tobacco mosaic virus and Escherichia coli bacterium. Throughout the 1990s and afterwards, researchers like Carlos Bustamante, James Spudich, and Steven Block pioneered the use of optical trap force spectroscopy to characterize molecular-scale biological motors. These molecular motors are ubiquitous in biology, and are responsible for locomotion and mechanical action within the cell. Optical traps allowed these biophysicists to observe the forces and dynamics of nanoscale motors at the single-molecule level; optical trap force-spectroscopy has since led to greater understanding of the stochastic nature of these force-generating molecules.
Optical tweezers have proven useful in other areas of biology as well. They are used in synthetic biology to construct tissue-like networks of artificial cells, and to fuse synthetic membranes together to initiate biochemical reactions. They are also widely employed in genetic studies and research on chromosome structure and dynamics. In 2003 the techniques of optical tweezers were applied in the field of cell sorting; by creating a large optical intensity pattern over the sample area, cells can be sorted by their intrinsic optical characteristics. Optical tweezers have also been used to probe the cytoskeleton, measure the visco-elastic properties of biopolymers, and study cell motility. A bio-molecular assay in which clusters of ligand coated nano-particles are both optically trapped and optically detected after target molecule induced clustering was proposed in 2011 and experimentally demonstrated in 2013.
Optical tweezers are also used to trap laser-cooled atoms in vacuum, mainly for applications in quantum science. Some achievements in this area include trapping of a single atom in 2001, trapping of 2D arrays of atoms in 2002, trapping of strongly interacting entangled pairs in 2010, trapping precisely assembled 2-dimensional arrays of atoms in 2016 and 3-dimensional arrays in 2018. These techniques have been used in quantum simulators to obtain programmable arrays of 196 and 256 atoms in 2021 and represent a promising platform for quantum computing.
Researchers have worked to convert optical tweezers from large, complex instruments to smaller, simpler ones, for use by those with smaller research budgets. | 1 | Applied and Interdisciplinary Chemistry |
Adjacent to the channel walls, the charge-neutrality of the liquid is violated due to the presence of the electrical double layer: a thin layer of counterions attracted by the charged surface.
The transport of counterions along with the pressure-driven fluid flow gives rise to a net charge transport: the streaming current. The reverse effect, generating a fluid flow by applying a potential difference, is called electroosmotic flow. | 0 | Theoretical and Fundamental Chemistry |
3-sulfolene is mainly valued as a stand-in for butadiene. The in situ production and immediate consumption of 1,3-butadiene largely avoids contact with the diene, which is a gas at room temperature. One potential drawback, aside from expense, is that the evolved sulfur dioxide can cause side reactions with acid-sensitive substrates.
Diels-Alder reaction between 1,3-butadiene and dienophiles of low reactivity usually requires prolonged heating above 100 °C. Such procedures are rather dangerous. If neat butadiene is used, special equipment for work under elevated pressure is required. With sulfolene no buildup of butadiene pressure could be expected as the liberated diene is consumed in the cycloaddition, and therefore the equilibrium of the reversible extrusion reaction acts as an internal "safety valve".
3-Sulfolene reacts with maleic anhydride in boiling xylene to cis-4-cyclohexene-1,2-dicarboxylic anhydride, obtaining yields of up to 90%.
3-Sulfolene reacts also with dienophiles in trans configuration (such as diethyl fumarate) at 110 °C with SO elimination in 66–73% yield to the trans-4-cyclohexene-1,2-dicarboxylic diethyl ester.
6,7-Dibromo-1,4-epoxy-1,4-dihydronaphthalene (6,7-Dibromonaphthalene-1,4-endoxide, accessible after debromination from 1,2,4,5-tetrabromobenzene using an equivalent of n-butyllithium and Diels-Alder reaction in furan in 70% yield) reacts with 3-sulfolene in boiling xylene to give a tricyclic adduct. This precursor yields, after treatment with perchloric acid, a dibromo dihydroanthracene which is dehydrogenated in the last step with 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) to 2,3-dibromoanthracene.
1,3-Butadiene (formed in the retro-cheletrophic reaction of 3-sulfolene) reacts with dehydrobenzene (benzyne, obtained by thermal decomposition of benzenediazonium-2-carboxylate) in a Diels-Alder reaction in 9% yield to give 1,4-dihydronaphthalene. | 0 | Theoretical and Fundamental Chemistry |
Henry Cavendish ( ; 10 October 1731 – 24 February 1810) was an English natural philosopher and scientist who was an important experimental and theoretical chemist and physicist. He is noted for his discovery of hydrogen, which he termed "inflammable air". He described the density of inflammable air, which formed water on combustion, in a 1766 paper, On Factitious Airs. Antoine Lavoisier later reproduced Cavendish's experiment and gave the element its name.
A shy man, Cavendish was distinguished for great accuracy and precision in his researches into the composition of atmospheric air, the properties of different gases, the synthesis of water, the law governing electrical attraction and repulsion, a mechanical theory of heat, and calculations of the density (and hence the mass) of the Earth. His experiment to measure the density of the Earth (which, in turn, allows the gravitational constant to be calculated) has come to be known as the Cavendish experiment. | 1 | Applied and Interdisciplinary Chemistry |
Monotherapy, or the use of a single therapy, can be applied to any therapeutic approach, but it is most commonly used to describe the use of a single medication. Normally, monotherapy is selected because a single medication is adequate to treat the medical condition. However, monotherapies may also be used because of unwanted side effects or dangerous drug interactions. | 1 | Applied and Interdisciplinary Chemistry |
Filing is combination of grinding and saw tooth cutting using a file. Prior to the development of modern machining equipment it provided a relatively accurate means for the production of small parts, especially those with flat surfaces. The skilled use of a file allowed a machinist to work to fine tolerances and was the hallmark of the craft. Today filing is rarely used as a production technique in industry, though it remains as a common method of deburring. | 1 | Applied and Interdisciplinary Chemistry |
In biochemistry, Michaelis–Menten kinetics, named after Leonor Michaelis and Maud Menten, is the simplest case of enzyme kinetics, applied to enzyme-catalysed reactions of one substrate and one product. It takes the form of a differential equation describing the reaction rate (rate of formation of product P, with concentration ) to , the concentration of the substrate A (using the symbols recommended by the IUBMB). Its formula is given by the Michaelis–Menten equation:
, which is often written as , represents the limiting rate approached by the system at saturating substrate concentration for a given enzyme concentration. The Michaelis constant is defined as the concentration of substrate at which the reaction rate is half of . Biochemical reactions involving a single substrate are often assumed to follow Michaelis–Menten kinetics, without regard to the model's underlying assumptions. Only a small proportion of enzyme-catalysed reactions have just one substrate, but the equation still often applies if only one substrate concentration is varied. | 0 | Theoretical and Fundamental Chemistry |
A chloroplast () is a type of membrane-bound organelle known as a plastid that conducts photosynthesis mostly in plant and algal cells. The photosynthetic pigment chlorophyll captures the energy from sunlight, converts it, and stores it in the energy-storage molecules ATP and NADPH while freeing oxygen from water in the cells. The ATP and NADPH is then used to make organic molecules from carbon dioxide in a process known as the Calvin cycle. Chloroplasts carry out a number of other functions, including fatty acid synthesis, amino acid synthesis, and the immune response in plants. The number of chloroplasts per cell varies from one, in unicellular algae, up to 100 in plants like Arabidopsis and wheat.
A chloroplast is characterized by its two membranes and a high concentration of chlorophyll. Other plastid types, such as the leucoplast and the chromoplast, contain little chlorophyll and do not carry out photosynthesis.
Chloroplasts are highly dynamic—they circulate and are moved around within plant cells, and occasionally pinch in two to reproduce. Their behavior is strongly influenced by environmental factors like light color and intensity. Chloroplasts, like mitochondria, contain their own DNA, which is thought to be inherited from their ancestor—a photosynthetic cyanobacterium that was engulfed by an early eukaryotic cell. Chloroplasts cannot be made by the plant cell and must be inherited by each daughter cell during cell division.
With one exception (the amoeboid Paulinella chromatophora), all chloroplasts can probably be traced back to a single endosymbiotic event, when a cyanobacterium was engulfed by a eukaryote. Despite this, chloroplasts can be found in an extremely wide set of organisms, some not directly related to each other—a consequence of many secondary and even tertiary endosymbiotic events.
The word chloroplast is derived from the Greek words chloros (χλωρός), which means green, and plastes (πλάστης), which means "the one who forms". | 0 | Theoretical and Fundamental Chemistry |
Following initial observations that some peptide-peptide complexes could survive MALDI deposition and ionization, studies of large protein complexes using MALDI-MS have been reported. | 1 | Applied and Interdisciplinary Chemistry |
Various hydrates of zinc chloride are known: with n = 1, 1.33, 2.5, 3, and 4.5. However, only the 1.33-hydrate, hemipentahydrate, trihydrate, and the heminonahydrate has been structurally elucidated.
The 1.33-hydrate, previously thought to be the hemitrihydrate, consists of trans-Zn(HO)Cl centers with the chlorine atoms connected to repeating ZnCl chains. The hemipentahydrate, structurally formulated [Zn(HO)][ZnCl], consists of Zn(HO)Cl octahedrons where the chlorine atom is part of a [ZnCl] tetrahedera. The trihydrate consists of distinct hexaaquozinc(II) cations and tetrachlorozincate anions; formulated [Zn(HO)][ZnCl]. Finally, the heminonahydrate, structurally formulated [Zn(HO)][ZnCl]·3HO also consists of distinct hexaaquozinc(II) cations and tetrachlorozincate anions like the trihydrate but has three extra water molecules. | 0 | Theoretical and Fundamental Chemistry |
The Cegelski Lab investigates the structure and function of bacterial cell walls and extracellular structures, including amyloid fibers and biofilms. | 0 | Theoretical and Fundamental Chemistry |
PELP1 is a proto-oncogene that provides cancer cells with a distinct growth and survival advantage. PELP1 overexpression has been reported in many cancers. PELP1 expression is an independent prognostic predictor of shorter breast cancer–specific survival and disease free interval. Patients whose tumors had high levels of cytoplasmic PELP1 exhibited a tendency to respond poorly to tamoxifen and PELP1 deregulated tumors respond to Src kinase and mTOR inhibitors. Treatment of breast and ovarian cancer xenografts with liposomal PELP1–siRNA–DOPC formulations revealed that knockdown of PELP1 significantly reduce the tumor growth. These results provided initial proof that PELP1 is a bonafide therapeutic target. Emerging data support a central role for PELP1 and its direct protein–protein interactions in cancer progression. Since PELP1 lacks known enzymatic activity, drugs that target PELP1 interactions with other proteins should have clinical utility. Recent studies described an inhibitor (D2) that block PELP1 interactions with AR. Since PELP1 interacts with histone modifications and epigenetic enzymes, drugs targeting epigenetic modifier enzymes may be useful in targeting PELP1 deregulated tumors. | 1 | Applied and Interdisciplinary Chemistry |
In chemistry, chemical purity is the measurement of the amount of impurities found in a sample. Several grades of purity are used by the scientific, pharmaceutical, and industrial communities. Some of the commonly used grades of purity include:
* ACS grade is the highest level of purity, and meets the standards set by the American Chemical Society (ACS). The official descriptions of the ACS levels of purity is documented in the Reagent Chemicals publication, issued by the ACS. It is suitable for food and laboratory uses.
* Reagent grade is almost as stringent as the ACS grade.
* USP grade meets the purity levels set by the United States Pharmacopeia (USP). USP grade is equivalent to the ACS grade for many drugs.
* NF grade is a purity grade set by the National Formulary (NF). NF grade is equivalent to the ACS grade for many drugs.
* British Pharmacopoeia: Meets or exceeds requirements set by the British Pharmacopoeia (BP). Can be used for food, drug, and medical purposes, and also for most laboratory purposes.
*Japanese Pharmacopeia: Meets or exceeds requirements set by the Japanese Pharmacopoeia (JP). Can be used for food, drug, and medical purposes, and also for most laboratory purposes.
* Laboratory grade is suitable for use in educational settings, but is not acceptable for food or drug use.
* Purified grade is not precisely defined, and it is not suitable for drug or food usage.
* Technical grade is suitable for industrial applications, but is not acceptable for food or drug use. | 1 | Applied and Interdisciplinary Chemistry |
Reaction progress kinetic analysis relies on the ability to accurately monitor the reaction conversion over time. This goal may be accomplished by a range of techniques, the most common of which are described below. While these techniques are sometimes categorized as differential (monitoring reaction rate over time) or integral (monitoring the amount of substrate and/or product over time), simple mathematical manipulation (differentiation or integration) allows interconversion of the data obtained by either of the two. Regardless of the technique implemented, it is generally advantageous to confirm the validity in the system of interest by monitoring with an additional independent method. | 0 | Theoretical and Fundamental Chemistry |
Several strategies exist for avoiding β-hydride elimination. The most common strategy is to employ alkyl ligands that do not have any hydrogen atoms at the β position. Common substituents include methyl and neopentyl. β-Hydride elimination is also inhibited when the reaction would produce a strained alkene. This situation is illustrated by the stability of metal complexes containing norbornyl ligands, where the β-hydride elimination product would violate Bredt's rule.
Bulky alkyl ligands, such as tert-butyl or trimethylsilyl, may prohibit the hydrogen atom from approaching a coplanar configuration with respect to the metal, and the α and β atoms. If the metal center does not have empty coordination sites, for example by the complex already having an 18-electron configuration, β-hydride elimination is not possible as well.
In some cases, the coligands can impose geometries that inhibit β-hydride elimination. For the above example, the unwanted β-hydride elimination is prevented by using a diphosphine where the two phosphorus atoms are fixed apart in space. One way of doing this is to use a trans spanning ligand such as Xantphos. As these metal complexes traditionally form square planar geometries, no vacant site cis to the alkyl group can be formed. Hence the β-hydride elimination is prevented. (See trans-spanning ligand.) | 0 | Theoretical and Fundamental Chemistry |
When the weights have been correctly derived from estimates of experimental error, the expectation value of is 1. It is therefore very useful to estimate experimental errors and derive some reasonable weights from them as this is an absolute indicator of the goodness of fit.
When unit weights are used, it is implied that all observations have the same variance. is expected to be equal to that variance. | 0 | Theoretical and Fundamental Chemistry |
In an anisotropic medium, such as a crystal, the polarisation field P is not necessarily aligned with the electric field of the light E. In a physical picture, this can be thought of as the dipoles induced in the medium by the electric field having certain preferred directions, related to the physical structure of the crystal. This can be written as:
Here χ is not a number as before but a tensor of rank 2, the electric susceptibility tensor. In terms of components in 3 dimensions:
or using the summation convention:
Since χ is a tensor, P is not necessarily colinear with E.
In nonmagnetic and transparent materials, χ = χ, i.e. the χ tensor is real and symmetric. In accordance with the spectral theorem, it is thus possible to diagonalise the tensor by choosing the appropriate set of coordinate axes, zeroing all components of the tensor except χ, χ and χ. This gives the set of relations:
The directions x, y and z are in this case known as the principal axes of the medium. Note that these axes will be orthogonal if all entries in the χ tensor are real, corresponding to a case in which the refractive index is real in all directions.
It follows that D and E are also related by a tensor:
Here ε is known as the relative permittivity tensor or dielectric tensor. Consequently, the refractive index of the medium must also be a tensor. Consider a light wave propagating along the z principal axis polarised such the electric field of the wave is parallel to the x-axis. The wave experiences a susceptibility χ and a permittivity ε. The refractive index is thus:
For a wave polarised in the y direction:
Thus these waves will see two different refractive indices and travel at different speeds. This phenomenon is known as birefringence and occurs in some common crystals such as calcite and quartz.
If χ = χ ≠ χ, the crystal is known as uniaxial. (See Optic axis of a crystal.) If χ ≠ χ and χ ≠ χ the crystal is called biaxial. A uniaxial crystal exhibits two refractive indices, an "ordinary" index (n) for light polarised in the x or y directions, and an "extraordinary" index (n) for polarisation in the z direction. A uniaxial crystal is "positive" if n > n and "negative" if n . Light polarised at some angle to the axes will experience a different phase velocity for different polarization components, and cannot be described by a single index of refraction. This is often depicted as an index ellipsoid. | 0 | Theoretical and Fundamental Chemistry |
Black shales are organic rich, microlaminated sedimentary rocks often associated with bottom water anoxia. This is because anoxia slows the degradation of organic matter, allowing for greater burial in the sediments. Other evidence for anoxic burial of black shale includes the lack of bioturbation, meaning that there were no organisms burrowing into the sediment because there was no oxygen for respiration. There must also be a source of organic matter for burial, generally from production near the oxic surface. Many papers discussing ancient euxinic events use the presence of black shale as a preliminary proxy for anoxic bottom waters, but their presence does not in and of itself indicate euxinia or even strong anoxia. Generally geochemical testing is needed to provide better evidence for conditions. | 0 | Theoretical and Fundamental Chemistry |
The White cell was first described in 1942 by John U. White in his paper Long Optical Paths of Large Aperture, and was a significant improvement over previous long path spectroscopic measurement techniques. A White cell is constructed using three spherical, concave mirrors having the same radius of curvature. The mirrors are separated by a distance equal to their radii of curvature. The animation on the right shows a White Cell in which a beam makes eight reflective passes or traversals. The number of traversals can be changed quite easily by making slight rotational adjustments to either M2 or M3; however, the total number of traversals must always occur in multiples of four. The entering and exiting beams do not change position as traversals are added or removed, while the total number of traversals can be increased many times without changing the volume of the cell, and therefore the total optical path length can be made large compared to the volume of the sample under test. The spots from various passes can overlap on mirrors M2 and M3 but must be distinct on mirror M1. If the input beam is focused in the plane of M1, then each round trip will also be focused in this plane. The tighter the focus, the more nonoverlapping spots there can be on M1 and thus the higher the maximum pathlength.
At present the White cell is still the most commonly used multipass cell and provides many advantages. For example,
* The number of traversals is easily controlled
* It allows for high numerical aperture
* It is reasonably stable (but not as stable as the Herriott cell)
White cells are available with path lengths ranging from less than a meter to many hundreds of meters. | 0 | Theoretical and Fundamental Chemistry |
MOSE is part of a General Plan of Interventions to safeguard Venice and the lagoon. The project was begun in 1987 by the Ministry of Infrastructure through the Venice Water Authority (the Ministrys operational arm in the lagoon) and the concessionary Consorzio Venezia Nuova'. The measures already completed or underway along the coastline and in the lagoon are the most important environmental defense, restoration, and improvement program ever implemented by the Italian State.
In parallel with the construction of MOSE, the Venice Water Authority and Venice Local Authority are raising quaysides and paving in the city in order to protect built-up areas in the lagoon from medium high tides (below , the height at which the mobile barriers will come into operation). These measures are extremely complex, particularly in urban settings such as Venice and Chioggia where the raising must take account of the delicate architectural and monumental context.
Measures to improve the shallow lagoon environment are aimed at slowing degradation of the morphological structures caused by subsidence, eustatism, and erosion due to waves and wash. Work is underway throughout the lagoon basin to protect, reconstruct, and renaturalise salt marshes, mud flats and shallows; restore the environment of the smaller islands; and dredge lagoon canals and channels.
Important activities are also underway to redress pollution in the industrial area of Porto Marghera, at the edge of the central lagoon. Islands formerly used as rubbish dumps are being secured while industrial canals are being consolidated and sealed after removal of their polluted sediments. | 1 | Applied and Interdisciplinary Chemistry |
* Tutorials in Molecular Reaction Dynamics. RSC Press, 2010. (Joint editor with Mark Brouard)
* Astrochemistry: from the Big Bang to the Present Day, World Scientific Press, 2017.
*An Introduction to Chemical Kinetics, Morgan-Claypool Publishing, 2017
*An Introduction to the Gas Phase, Morgan-Claypool Publishing, 2018 | 0 | Theoretical and Fundamental Chemistry |
An example of aluminum alloys where solid solution strengthening happens by adding magnesium and manganese into the aluminum matrix. Commercially Mn can be added to the AA3xxx series and Mg can be added to the AA5xxx series. Mn addition to the Aluminum alloys assists in the recrystallization and recovery of the alloy which influences the grain size as well. Both of these systems are used in low to medium-strength applications, with appreciable formability and corrosion resistance. | 1 | Applied and Interdisciplinary Chemistry |
The respiratory quotient (RQ) is the ratio:
RQ = CO / O
where the term "eliminated" refers to carbon dioxide (CO) removed from the body.
In this calculation, the CO and O must be given in the same units, and in quantities proportional to the number of molecules. Acceptable inputs would be either moles, or else volumes of gas at standard temperature and pressure.
Many metabolized substances are compounds containing only the elements carbon, hydrogen, and oxygen. Examples include fatty acids, glycerol, carbohydrates, deamination products, and ethanol. For complete oxidation of such compounds, the chemical equation is
CHO + (x + y/4 - z/2) O
→ x CO + (y/2) HO
and thus metabolism of this compound gives an RQ of x/(x + y/4 - z/2).
For glucose, with the molecular formula, CHO, the complete oxidation equation is CHO + 6 O
→ 6 CO + 6 HO. Thus, the RQ= 6 CO/ 6 O=1.
For fats, the RQ depends on the specific fatty acids present. Amongst the commonly stored fatty acids in vertebrates, RQ varies from 0.692 (stearic acid) to as high as 0.759 (docosahexaenoic acid). Historically, it was assumed that average fat had an RQ of about 0.71, and this holds true for most mammals including humans. However, a recent survey showed that aquatic animals, especially fish, have fat that should yield higher RQs on oxidation, reaching as high as 0.73 due to high amounts of docosahexaenoic acid.
The range of respiratory coefficients for organisms in metabolic balance usually ranges from 1.0 (representing the value expected for pure carbohydrate oxidation) to ~0.7 (the value expected for pure fat oxidation). In general, molecules that are more oxidized (e.g., glucose) require less oxygen to be fully metabolized and, therefore, have higher respiratory quotients. Conversely, molecules that are less oxidized (e.g., fatty acids) require more oxygen for their complete metabolism and have lower respiratory quotients. See BMR for a discussion of how these numbers are derived. A mixed diet of fat and carbohydrate results in an average value between these numbers.
RQ value corresponds to a caloric value for each liter (L) of CO produced. If O consumption numbers are available, they are usually used directly, since they are more direct and reliable estimates of energy production.
RQ as measured includes a contribution from the energy produced from protein. However, due to the complexity of the various ways in which different amino acids can be metabolized, no single RQ can be assigned to the oxidation of protein in the diet.
Insulin, which increases lipid storage and decreases fat oxidation, is positively associated with increases in the respiratory quotient. A positive energy balance will also lead to an increased respiratory quotient. | 1 | Applied and Interdisciplinary Chemistry |
Packed columns utilizing filter media for chemical exchange are the most common devices used in the chemical industry for reactant contact optimization. Packed columns are used in a range of industries to allow intimate contact between two immiscible/partly immiscible fluids, which can be liquid/gas or liquid/liquid. The fluids are passed through a column in a countercurrent flow.
In the column it is important to maintain an effective mass transfer, so its essential that a packing is selected which will support a large surface area for mass transfer. | 1 | Applied and Interdisciplinary Chemistry |
Within the field of molecular biology, a protein-fragment complementation assay, or PCA, is a method for the identification and quantification of protein–protein interactions. In the PCA, the proteins of interest ("bait" and "prey") are each covalently linked to fragments of a third protein (e.g. DHFR, which acts as a "reporter"). Interaction between the bait and the prey proteins brings the fragments of the reporter protein in close proximity to allow them to form a functional reporter protein whose activity can be measured. This principle can be applied to many different reporter proteins and is also the basis for the yeast two-hybrid system, an archetypical PCA assay. | 1 | Applied and Interdisciplinary Chemistry |
Consider the Navier-Stokes equations instead of Euler equations,
and we define the shear-energy tensor as
With the condition that the normal component of the total stress on the free surface must vanish, i.e., , where is the outward unit normal, the second order virial equation then be
This can be easily extended to rotating frame of references. | 1 | Applied and Interdisciplinary Chemistry |
The idea of corresponding states originated when van der Waals cast his equation in the dimensionless form, . However, as Boltzmann noted, such a simple representation could not correctly describe all substances. Indeed, the saturation analysis of this form produces , namely all substances have the same dimensionless coexistence curve. In order to avoid this paradox an extended principle of corresponding states has been suggested in which where is a substance dependent dimensionless parameter related to the only physical feature associated with an individual substance, its critical point.
The first candidate for was the critical compressibility factor , but because that quantity is difficult to measure accurately, the acentric factor developed by Kenneth Pitzer, , is more useful. The saturation pressure in this situation is represented by a one parameter family of curves, . Several investigators have produced correlations of saturation data for a number of substances, the best is that of Dong and Lienhard,
which has an rms error of over the range
Figure 3 is a plot of vs . for various values of as given by this equation. The ordinate is logarithmic in order to show the behavior at pressures far below the critical where differences among the various substances (indicated by varying values of ) are more pronounced.
Figure 4 is another plot of the same equation showing as a function of for various values of . It includes data from 51 substances including the vdW fluid over the range . This plot shows clearly that the vdW fluid () is a member of the class of real fluids; indeed it quantitatively describes the behavior of the liquid metals cesium () and mercury () whose values of are close to the vdW value. However, it describes the behavior of other fluids only qualitatively, because specific numerical values are modified by differing values of their Pitzer factor, . | 0 | Theoretical and Fundamental Chemistry |
Featuring divalent carbon, vinylidenes are unusual species in organic chemistry. They are unstable as solids or liquids but can be generated as stable dilute gases. The parent member of this series is methylidenecarbene. With the formula :C=CH), it is a carbene. | 0 | Theoretical and Fundamental Chemistry |
Dansyl amide is a fluorescent dye that forms in a reaction between dansyl chloride and ammonia. It is the simplest representative of the class of dansyl derivatized amines, which are widely used in biochemistry and chemistry as fluorescent labels. The dansyl amide moiety is also called a dansyl group, and it can be introduced into amino acids or other amines in a reaction with dansyl chloride. The dansyl group is highly fluorescent, and it has a very high Stokes shift. The excitation maximum (ca 350 nm) is essentially independent on the medium, whereas the emission maximum strongly depends on the solvent and varies from 520 to 550 nm. | 0 | Theoretical and Fundamental Chemistry |
The magnitude of sensory impairment may vary in people of differing weights. The NIAAA defines the term "binge drinking" as a pattern of drinking that brings a person's blood alcohol concentration (BAC) to 0.08 grams percent or above. | 1 | Applied and Interdisciplinary Chemistry |
A sample injector is a device used in conjunction with injecting samples into high-performance liquid chromatography (HPLC) or similar chromatography apparati. | 0 | Theoretical and Fundamental Chemistry |
The dynamics of surfactant adsorption is of great importance for practical applications such as in foaming, emulsifying or coating processes, where bubbles or drops are rapidly generated and need to be stabilized. The dynamics of absorption depend on the diffusion coefficient of the surfactant. As the interface is created, the adsorption is limited by the diffusion of the surfactant to the interface. In some cases, there can exist an energetic barrier to adsorption or desorption of the surfactant. If such a barrier limits the adsorption rate, the dynamics are said to be ‘kinetically limited'. Such energy barriers can be due to steric or electrostatic repulsions.
The surface rheology of surfactant layers, including the elasticity and viscosity of the layer, play an important role in the stability of foams and emulsions. | 0 | Theoretical and Fundamental Chemistry |
Flooding in houses causes a unique opportunity for mold growth, which may be attributed to adverse health effects in people exposed to the mold, especially children and adolescents. In a study on the health effects of mold exposure after hurricanes Katrina and Rita, the predominant types of mold were Aspergillus, Penicillium, and Cladosporium with indoor spore counts ranging from 6,142 – 735,123 spores m. Molds isolated following flooding were different from mold previously reported for non-water damaged homes in the area. Further research found that homes with greater than three feet of indoor flooding demonstrated significantly higher levels of mold than those with little or no flooding. | 1 | Applied and Interdisciplinary Chemistry |
Gas-diffusion electrocrystallization (GDEx) is an electrochemical process consisting on the reactive precipitation of metal ions in solution (or dispersion) with intermediaries produced by the electrochemical reduction of gases (such as oxygen), at gas diffusion electrodes. It can serve for the recovery of metals or metalloids into solid precipitates or for the synthesis of libraries of nanoparticles. | 0 | Theoretical and Fundamental Chemistry |
In , organic chemistry, a cyanohydrin or hydroxynitrile is a functional group found in organic compounds in which a cyano and a hydroxy group are attached to the same carbon atom. The general formula is , where R is H, alkyl, or aryl. Cyanohydrins are industrially important precursors to carboxylic acids and some amino acids. Cyanohydrins can be formed by the cyanohydrin reaction, which involves treating a ketone or an aldehyde with hydrogen cyanide (HCN) in the presence of excess amounts of sodium cyanide (NaCN) as a catalyst:
In this reaction, the nucleophilic ion attacks the electrophilic carbonyl carbon in the ketone, followed by protonation by HCN, thereby regenerating the cyanide anion. Cyanohydrins are also prepared by displacement of sulfite by cyanide salts:
Cyanohydrins are intermediates in the Strecker amino acid synthesis. In aqueous acid, they are hydrolyzed to the α-hydroxy acid. | 0 | Theoretical and Fundamental Chemistry |
Currently the biosynthesis of rhodoquinone (RQ) is still being debated, but there are two main biosynthetic pathways that are being researched. The first pathway requires the organism to produce ubiquinone (UQ) before the amino group can be added onto the quinone ring. The second pathway allows RQ to be synthesized without any UQ being present by using tryptophan metabolites instead.
In the case of the prokaryotic organism R. rubrum, RQ has been shown to be synthesized by addition of an amino group to a pre-existing UQ; thus UQ needs to be present as a precursor before RQ can be made. Figure 1 shows the biosynthesis of UQ in yeast and E. coli where ‘n’ represents the number of isoprene units between various organisms. Dimethylallyl diphosphate A and isopentyl diphosphate B come together to form polyisoprenyl diphosphate C. With the addition of p-hydroxybenzoic acid, the product that arises is 3-polyprenyl-4-hydroxybenzoic acid D. The next three steps of synthesis varies between different organisms, but molecule E is made across all organisms and through oxidation, demethyldemethoxyubiquinone (DDMQ) is eventually formed. RQ has been theorized to be synthesized from DDMQn, DMQn, DMeQn, or UQn, as shown with the dashed arrows. Recent studies have shown that Path 4 - RQ biosynthesis via UQ, is the favored route. It has been further shown that the gene rquA is required for the biosynthesis of RQ in R. rubrum, and that RquA catalyzes the conversion of UQ to RQ. The RquA protein uses S-adenosyl-L-methionine as the amino donor to convert UQ to RQ in an unusual Mn(II)-catalyzed reaction.
Research in C. elegans has shown an alternative path for production of RQ. Even after knocking out all UQ production, RQ is still present within those mutant strains. Based on this data, RQ production is not solely based on UQ-like molecules and instead can be made via tryptophan metabolites. Therefore, the amino group that is added in late stages of RQ biosynthesis in rquA-containing species is instead present throughout intermediate stages of RQ biosynthesis in C. elegans. With this proposed biosynthesis, the kynurenine pathway still needs to be upregulated, and activity from certain genes like kynu-1 which encodes for the KYNU-1 enzyme that catalyzes production of 3-hydroxy-L-kynurenine to 3-hydroxyanthranilic acid, needs to be upheld. Recent work has revealed that alternative splicing of the coq-2 polyprenyltransferase gene controls the level of RQ in animals. Animals that produce RQ (e.g. C. elegans and helminth parasites) contain both COQ-2 protein isoforms (COQ-2a and COQ-2e), and COQ-2e catalyzes prenylation of 3-hydroxyanthranilic acid (instead of p-hydroxybenzoic acid) which leads to RQ. | 1 | Applied and Interdisciplinary Chemistry |
Glutathione or its homologues, e.g. homoglutathione in Fabaceae; hydroxymethylglutathione in Poaceae are the major water-soluble non-protein thiol compounds present in plant tissue and account for 1-2% of the total sulfur. The content of glutathione in plant tissue ranges from 0.1 - 3 mM. Cysteine is the direct precursor for the synthesis of glutathione (and its homologues). First, γ-glutamylcysteine is synthesized from cysteine and glutamate catalyzed by gamma-glutamylcysteine synthetase. Second, glutathione is synthesized from γ-glutamylcysteine and glycine (in glutathione homologues, β-alanine or serine) catalyzed by glutathione synthetase. Both steps of the synthesis of glutathione are ATP dependent reactions. Glutathione is maintained in the reduced form by an NADPH-dependent glutathione reductase and the ratio of reduced glutathione (GSH) to oxidized glutathione (GSSG) generally exceeds a value of 7.
Glutathione fulfils various roles in plant functioning. In sulfur metabolism it functions as reductant in the reduction of APS to sulfite. It is also the major transport form of reduced sulfur in plants. Roots likely largely depend for their reduced sulfur supply on shoot/root transfer of glutathione via the phloem, since the reduction of sulfur occurs predominantly in the chloroplast. Glutathione is directly involved in the reduction and assimilation of selenite into selenocysteine. Furthermore, glutathione is of great significance in the protection of plants against oxidative and environmental stress and it depresses/scavenges the formation of toxic reactive oxygen species, e.g. superoxide, hydrogen peroxide and lipid hydroperoxides. Glutathione functions as reductant in the enzymatic detoxification of reactive oxygen species in the glutathione-ascorbate cycle and as thiol buffer in the protection of proteins via direct reaction with reactive oxygen species or by the formation of mixed disulfides. The potential of glutathione as protectant is related to the pool size of glutathione, its redox state (GSH/GSSG ratio) and the activity of glutathione reductase. Glutathione is the precursor for the synthesis of phytochelatins, which are synthesized enzymatically by a constitutive phytochelatin synthase. The number of γ-glutamyl-cysteine residues in the phytochelatins may range from 2 - 5, sometimes up to 11. Despite the fact that the phytochelatins form complexes which a few heavy metals, viz. cadmium, it is assumed that these compounds play a role in heavy metal homeostasis and detoxification by buffering of the cytoplasmatic concentration of essential heavy metals. Glutathione is also involved in the detoxification of xenobiotics, compounds without direct nutritional value or significance in metabolism, which at too high levels may negatively affect plant functioning. Xenobiotics may be detoxified in conjugation reactions with glutathione catalyzed by glutathione S-transferase, which activity is constitutive; different xenobiotics may induce distinct isoforms of the enzyme. Glutathione S-transferases have great significance in herbicide detoxification and tolerance in agriculture and their induction by herbicide antidotes (safeners) is the decisive step for the induction of herbicide tolerance in many crop plants. Under natural conditions glutathione S-transferases are assumed to have significance in the detoxification of lipid hydroperoxides, in the conjugation of endogenous metabolites, hormones and DNA degradation products, and in the transport of flavonoids. | 1 | Applied and Interdisciplinary Chemistry |
Nanoclusters potentially have many areas of application as they have unique optical, electrical, magnetic and reactivity properties. Nanoclusters are biocompatible, ultrasmall, and exhibit bright emission, hence promising candidates for fluorescence bio imaging or cellular labeling. Nanoclusters along with fluorophores are widely used for staining cells for study both in vitro and in vivo. Furthermore, nanoclusters can be used for sensing and detection applications. They are able to detect copper and mercury ions in an aqueous solution based on fluorescence quenching. Also many small molecules, biological entities such as biomolecules, proteins, DNA, and RNA can be detected using nanoclusters. The unique reactivity properties and the ability to control the size and number of atoms in nanoclusters have proven to be a valuable method for increasing activity and tuning the selectivity in a catalytic process. Also since nanoparticles are magnetic materials and can be embedded in glass these nanoclusters can be used in optical data storage that can be used for many years without any loss of data. | 0 | Theoretical and Fundamental Chemistry |
A size range coefficient of approximately three is advisable. A minimum amount of undersized fine material must enter the machines to optimize availability. Moisture of the feed is not important, if the material is sufficiently dewatered and the undersize fraction is efficiently removed. For surface detection technologies sometimes spray water on the classifying screen is required to clean the surfaces. Surface detection technologies would otherwise measure the reflectance of the adhesions on the surface and a correlation to the particle's content is not given. | 0 | Theoretical and Fundamental Chemistry |
The Calvin cycle accounts for 90% of biological carbon fixation. Consuming ATP and NADPH, the Calvin cycle in plants accounts for the preponderance of carbon fixation on land. In algae and cyanobacteria, it accounts for the preponderance of carbon fixation in the oceans. The Calvin cycle converts carbon dioxide into sugar, as triose phosphate (TP), which is glyceraldehyde 3-phosphate (GAP) together with dihydroxyacetone phosphate (DHAP):
:3 CO + 12 e + 12 H + P → TP + 4 HO
An alternative perspective accounts for NADPH (source of e) and ATP:
:3 CO + 6 NADPH + 6 H + 9 ATP + 5 HO → TP + 6 NADP + 9 ADP + 8 P
The formula for inorganic phosphate (P) is HOPO + 2H. Formulas for triose and TP are CHO-CHOH and CHO-CHOPO + 2H | 0 | Theoretical and Fundamental Chemistry |
Site selection for the FutureGen facility was based on a competitive process which began in May 2006. Seven states responded to the Site Request for Proposals with a total of 12 proposals. Proposals were reviewed against a set of environmental, technical, regulatory, and financial criteria with input from external technical advisors on power plant design and carbon sequestration. In July 2006, four candidate sites were selected for further review, including an environmental impact analysis as required by NEPA.
DOE issued its Final Environmental impact statement (EIS) on November 8, 2007, which concluded that all four sites were acceptable from an environmental impact standpoint and all would move forward in the site evaluation process. EPA published a Notice of Availability (NOA) for the EIS in the Federal Register on November 16, 2007. The DOE is required by federal law to wait at least 30 days after the NOA release before issuing its final Record of Decision (ROD). The waiting period legally closed on December 17, 2007. DOE chose not to issue the ROD and advised the FutureGen Alliance to delay the final site selection announcement, which was scheduled to occur at the end of the 30-day waiting period. The Alliance chose to move ahead with the announcement, citing time, money, and a commitment to proposers to select the final site by year-end. "Every month of delay can add $10 million to the projects cost, solely due to inflation," said Michael Mudd, the Alliances chief executive.
The FutureGen Alliance announced the selection of Mattoon, Illinois as the host site on December 18, 2007. According to the EIS, Mattoon, IL the site is located about northwest of downtown Mattoon in the eastern part of Mattoon township section 8 on of former farm land. The carbon sequestration area is about below the ground. In July 2007, Illinois Public Act 095-0018 became law giving the state of Illinois ownership of and liability for the sequestered gases. | 1 | Applied and Interdisciplinary Chemistry |
Ductile iron pipe is pipe made of ductile cast iron commonly used for potable water transmission and distribution. This type of pipe is a direct development of earlier cast iron pipe, which it has superseded. | 1 | Applied and Interdisciplinary Chemistry |
Diphosphene compounds usually exhibit a symmetry-allowed () (intense) and symmetry-forbidden electronic transitions () (weak). In Raman, there is significant enhancement of P=P stretch in the resonance with allowed electron transition than with the forbidden transition due to different geometries of excited states and enhancement mechanism. Also the observed strong Raman shifts for and suggest stronger dipnictenes feature of diphosphene compared with P-P single bond. | 0 | Theoretical and Fundamental Chemistry |
In the eighteenth century, with the rise of combustion analysis in chemistry, Stephen Hales invented the pneumatic trough in order to collect gases from the samples of matter he used; while uninterested in the properties of the gases he collected, he wanted to explore how much gas was given off from the materials he burned or let ferment. Hales was successful in preventing the air from losing its "elasticity," i.e. preventing it from experiencing a loss in volume, by bubbling the gas through water, and therefore dissolving the soluble gases.
After the invention of the pneumatic trough, Stephen Hales continued his research into the different airs, and performed many Newtonian analyses of the various properties of them. He published his book Vegetable Staticks in 1727, which had a profound impact on the field of pneumatic chemistry, as many researchers cited this in their academic papers. In Vegetable Staticks, Hales not only introduced his trough, but also published the results he obtained from the collected air, such as the elasticity and composition of airs along with their ability to mix with others. | 1 | Applied and Interdisciplinary Chemistry |
Shortly after World War II, when synthetic insecticides became widely available, entomologists in California developed the concept of "supervised insect control". Around the same time, entomologists in the US Cotton Belt were advocating a similar approach. Under this scheme, insect control was "supervised" by qualified entomologists and insecticide applications were based on conclusions reached from periodic monitoring of pest and natural-enemy populations. This was viewed as an alternative to calendar-based programs. Supervised control was based on knowledge of the ecology and analysis of projected trends in pest and natural-enemy populations.
Supervised control formed much of the conceptual basis for the "integrated control" that University of California entomologists articulated in the 1950s. Integrated control sought to identify the best mix of chemical and biological controls for a given insect pest. Chemical insecticides were to be used in the manner least disruptive to biological control. The term "integrated" was thus synonymous with "compatible." Chemical controls were to be applied only after regular monitoring indicated that a pest population had reached a level that required treatment (the economic threshold) to prevent the population from reaching a level at which economic losses would exceed the cost of the control measures (the economic injury level).
IPM extended the concept of integrated control to all classes of pests and was expanded to include all tactics. Controls such as pesticides were to be applied as in integrated control, but these now had to be compatible with tactics for all classes of pests. Other tactics, such as host-plant resistance and cultural manipulations, became part of the IPM framework. IPM combined entomologists, plant pathologists, nematologists and weed scientists.
In the United States, IPM was formulated into national policy in February 1972 when President Richard Nixon directed federal agencies to take steps to advance the application of IPM in all relevant sectors. In 1979, President Jimmy Carter established an interagency IPM Coordinating Committee to ensure development and implementation of IPM practices.
Perry Adkisson and Ray F. Smith received the 1997 World Food Prize for encouraging the use of IPM. | 0 | Theoretical and Fundamental Chemistry |
Murexide test is a color test for uric acid and some other purines. The (solid) sample is first treated with small volume of a concentrated acid such as hydrochloric acid, nitric acid, which is slowly evaporated away; subsequent addition of ammonia (NH) gives a purple color if uric acid was present, due to formation of murexide, or a yellow color that turns to red on heating if xanthine or its derivatives are present. | 0 | Theoretical and Fundamental Chemistry |
Transferrins are glycoproteins found in vertebrates which bind and consequently mediate the transport of iron (Fe) through blood plasma. They are produced in the liver and contain binding sites for two Fe ions. Human transferrin is encoded by the TF gene and produced as a 76 kDa glycoprotein.
Transferrin glycoproteins bind iron tightly, but reversibly. Although iron bound to transferrin is less than 0.1% (4 mg) of total body iron, it forms the most vital iron pool with the highest rate of turnover (25 mg/24 h). Transferrin has a molecular weight of around 80 kDa and contains two specific high-affinity Fe(III) binding sites. The affinity of transferrin for Fe(III) is extremely high (association constant is 10 M at pH 7.4) but decreases progressively with decreasing pH below neutrality. Transferrins are not limited to only binding to iron but also to different metal ions. These glycoproteins are located in various bodily fluids of vertebrates. Some invertebrates have proteins that act like transferrin found in the hemolymph.
When not bound to iron, transferrin is known as "apotransferrin" (see also apoprotein). | 1 | Applied and Interdisciplinary Chemistry |
Some nuclides can be induced to eject a neutron by gamma radiation. One such nuclide is Be; its photodisintegration is significant in nuclear astrophysics, pertaining to the abundance of beryllium and the consequences of the instability of Be. This also makes this isotope useful as a neutron source in nuclear reactors. Another nuclide, Ta, is also known to be readily capable of photodisintegration; this process is thought to be responsible for the creation of Ta, the only primordial nuclear isomer and the rarest primordial nuclide. | 0 | Theoretical and Fundamental Chemistry |
Perindopril shares the indications of ACE inhibitors as a class, including essential hypertension, stable coronary artery disease (reduction of risk of cardiac events in patients with a history of myocardial infarction and/or revascularization), treatment of symptomatic coronary artery disease or heart failure, and diabetic nephropathy. | 0 | Theoretical and Fundamental Chemistry |
In biochemistry and molecular biology, a binding site is a region on a macromolecule such as a protein that binds to another molecule with specificity. The binding partner of the macromolecule is often referred to as a ligand. Ligands may include other proteins (resulting in a protein–protein interaction), enzyme substrates, second messengers, hormones, or allosteric modulators. The binding event is often, but not always, accompanied by a conformational change that alters the protein's function. Binding to protein binding sites is most often reversible (transient and non-covalent), but can also be covalent reversible or irreversible. | 1 | Applied and Interdisciplinary Chemistry |
The Novartis-Drew Award for Biomedical Research is an award jointly presented by Novartis and Drew University. It comprises a cash award (originally $2000) and a plaque. The award was initially created as the Ciba-Drew Award for Biomedical Research and renamed following the change of company name from Ciba-Geigy to Novartis in 1996. | 1 | Applied and Interdisciplinary Chemistry |
To understand cases of real chemical reactions, the HOMO-LUMO-centered view is modified by understanding of further complex, electrophile-specific repulsive and attractive electrostatic and Van der Waals interactions that alter the altitudinal BD angle, and bias the azimuthal Flippin-Lodge angle toward one substituent or the other (see graphic above). | 0 | Theoretical and Fundamental Chemistry |
Isotopic data from various locations within the Mid-Atlantic Ridge indicates the presence of mafic-to-felsic intrusive igneous rocks, including gabbro, diorite, and plagiogranite. These rocks showed high-grade metamorphism because of the presence of magmatic water, exceeding 600 °C. This deformation depleted host rocks of O, leading to further analysis of the ratio of O to O (δO).
Water in equilibrium with igneous melts should bear the same isotopic signature for O and δH. However, isotopic studies of magmatic water have demonstrated similarities to meteoric water, indicating circulation of magmatic and meteoric groundwater systems.
Isotopic analyses of fluid inclusions indicate a wide range of δO and δH content. Studies within these environments have shown an abundance of O and depletion in H relative to SMOW and meteoric waters. Within ore deposits, fluid inclusion data showed that the presence of δO vs δH are within the expected range. | 0 | Theoretical and Fundamental Chemistry |
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