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Plasma temperature, commonly measured in kelvin or electronvolts, is a measure of the thermal kinetic energy per particle. High temperatures are usually needed to sustain ionization, which is a defining feature of a plasma. The degree of plasma ionization is determined by the electron temperature relative to the ionization energy (and more weakly by the density). In thermal equilibrium, the relationship is given by the Saha equation. At low temperatures, ions and electrons tend to recombine into bound states—atoms—and the plasma will eventually become a gas.
In most cases, the electrons and heavy plasma particles (ions and neutral atoms) separately have a relatively well-defined temperature; that is, their energy distribution function is close to a Maxwellian even in the presence of strong electric or magnetic fields. However, because of the large difference in mass between electrons and ions, their temperatures may be different, sometimes significantly so. This is especially common in weakly ionized technological plasmas, where the ions are often near the ambient temperature while electrons reach thousands of kelvin. The opposite case is the z-pinch plasma where the ion temperature may exceed that of electrons. | 0 | Theoretical and Fundamental Chemistry |
Take the simple example of a barotropic, inviscid vorticity-free fluid.
Then, the conjugate fields are the mass density field ρ and the velocity potential φ. The Poisson bracket is given by
and the Hamiltonian by:
where e is the internal energy density, as a function of ρ.
For this barotropic flow, the internal energy is related to the pressure p by:
where an apostrophe (), denotes differentiation with respect to ρ'.
This Hamiltonian structure gives rise to the following two equations of motion:
where is the velocity and is vorticity-free. The second equation leads to the Euler equations:
after exploiting the fact that the vorticity is zero:
As fluid dynamics is described by non-canonical dynamics, which possess an infinite amount of Casimir invariants, an alternative formulation of Hamiltonian formulation of fluid dynamics can be introduced through the use of Nambu mechanics | 1 | Applied and Interdisciplinary Chemistry |
Instead of light, this method employs ultrasound for collecting information on the particles that are dispersed in fluid. Dispersed particles absorb and scatter ultrasound similarly to light. This has been known since Lord Rayleigh developed the first theory of ultrasound scattering and published a book "The Theory of Sound" in 1878. There have been hundreds of papers studying ultrasound propagation through fluid particulates in the 20th century. It turns out that instead of measuring scattered energy versus angle, as with light, in the case of ultrasound, measuring the transmitted energy versus frequency is a better choice. The resulting ultrasound attenuation frequency spectra are the raw data for calculating particle size distribution. It can be measured for any fluid system with no dilution or other sample preparation. This is a big advantage of this method. Calculation of particle size distribution is based on theoretical models that are well verified for up to 50% by volume of dispersed particles on micron and nanometer scales. However, as concentration increases and the particle sizes approach the nanoscale, conventional modelling gives way to the necessity to include shear-wave re-conversion effects in order for the models to accurately reflect the real attenuation spectra. | 0 | Theoretical and Fundamental Chemistry |
Genomes can be analyzed systematically to identify regulatory regions. Conserved non-coding sequences often contain regulatory regions, and so they are often the subject of these analyses.
* CAAT box
* CCAAT box
* Operator (biology)
* Pribnow box
* TATA box
* SECIS element, mRNA
* Polyadenylation signal, mRNA
* A-box
* Z-box
* C-box
* E-box
* G-box | 1 | Applied and Interdisciplinary Chemistry |
Thermochemistry aside, the rate of metabolism and an amount of energy expenditures can be mistakenly interchanged, for example, when describing RMR and REE. | 1 | Applied and Interdisciplinary Chemistry |
Silicone-based defoamers are polymers with silicon backbones. These might be delivered as an oil or a water-based emulsion. The silicone compound consists of a hydrophobic silica dispersed in a silicone oil. Emulsifiers are added to ensure that the silicone spreads fast and well in the foaming medium. The silicone compound might also contain silicone glycols and other modified silicone fluids.
These are also heavy duty defoamers and are good at both knocking down surface foam and releasing entrained air.
Silicone-based defoamers are also suitable in non-aqueous foaming systems like crude oil and oil refining. For very demanding applications fluorosilicones may be suitable.
EO/PO-based defoamers contain polyethylene glycol and polypropylene glycol copolymers. They are delivered as oils, water solutions, or water-based emulsions. EO/PO copolymers normally have good dispersing properties and are often well suited when deposit problems are an issue. | 0 | Theoretical and Fundamental Chemistry |
The Jet Propulsion Laboratory proposed to design and develop the AVIRIS in 1983. AVIRIS first measured spectral images in 1987 and measured the solar reflected spectrum from 400 nanometers to 2500 nanometers. AVIRIS measures upwelling radiance through 224 contiguous spectral channels at 10 nanometer intervals across the spectrum. | 0 | Theoretical and Fundamental Chemistry |
TiAl has the lowest density of 3.4 g/cm, the highest micro hardness of 465–670 kg/mm and the best oxidation resistance even at 1 000 °C. However, the applications of TiAl in the engineering and aerospace fields are limited by its poor ductility. In addition, the loss of ductility at ambient temperature is usually accompanied by a change of fracture mode from ductile transgranular to brittle intergranular or to brittle cleavage. Despite the fact that a lot of toughening strategies have been developed to improve their toughness, machining quality is still a difficult problem to tackle. Near-net shape manufacturing technology is considered as one of the best choices for preparing such materials. {date=July 2022} | 1 | Applied and Interdisciplinary Chemistry |
Most cancer cells cause mutation in the bodies' metabolic activities to increase glucose metabolism in order to rapidly proliferate. Mutations that increase the cells metabolic activity and turn a normal cell into a tumor cell are called oncogenes. Cancer cells are unlike many other cells. They have very little vulnerabilities, but experiments in which the inhibition of transamination of malate-shuttle slowed proliferation due to the fact metabolism of glucose was being slowed. | 1 | Applied and Interdisciplinary Chemistry |
Apoaequorin is an ingredient in "Prevagen", which is marketed by Quincy Bioscience as a memory supplement. In 2017, the US Federal Trade Commission (FTC) charged the maker with falsely advertising that the product improves memory, provides cognitive benefits, and is "clinically shown" to work. According to the FTC, "the marketers of Prevagen preyed on the fears of older consumers experiencing age-related memory loss". Quincy said that it would fight the charges.
Prior to the suit, a clinical trial run by researchers employed by Quincy Bioscience "found no overall benefit compared to a placebo for its primary endpoints involving memory and cognition", while the company's advertising misleadingly cited a few contested subgroup analyses that showed slight improvements.
The suit (Spath, et al. v. Quincy Bioscience Holding Company, Inc., et al., Case No. 18-cv-12416, D. NJ.) was dismissed in the District court, but an appeal seeking to overturn the dismissal was filed. The suit was consolidated with another against Quincy Pharmaceuticals, Vanderwerff v. Quincy Bioscience (Case No. 17-cv-784, D. NJ), which was the lead case.
On February 21, 2019, the United States Court of Appeals for the Second Circuit ruled that the FTC and the state of New York could proceed with their lawsuit against Quincy Bioscience for its claims that Prevagen can improve memory. The order came less than two weeks after the parties argued the case before a three-judge panel of the circuit, where company lawyers admitted they did not "dispute that if you look across the entire 211 people who completed the study there was no statistically significant difference". The court vigorously dismissed allegations by the company lawyers that the FTC pursued its action for political reasons.
On March 23, 2020, a federal magistrate judge in the United States District Court for the Southern District of Florida entered a report and recommendations certifying a nationwide class action for the class of consumers who purchased Prevagen over the previous four years. The trial in the case was set for October 2020.
Quincy Bioscience agreed to settle the claims that it misrepresented its Prevagen products as supporting brain health and helping with memory loss. Under the terms of the settlement, eligible purchasers applying by October 26, 2020 for purchases made from 2007 through July 31, 2020 could recover refunds of up to $70.
Dr. Harriet Hall, writing for Science-Based Medicine, noted that the Quincy-sponsored study (known as "Madison Memory Study") was negative, but that the company utilized p-hacking to find favorable results. She wrote that their cited safety studies were all rat studies and their claim that apoaequorin crosses the blood–brain barrier was based solely on a dog study. The American Pharmacists Association warns that Apoaequorin "is unlikely to be absorbed to a significant degree; instead it degrades into amino acids". | 1 | Applied and Interdisciplinary Chemistry |
1968 – Ralph E. Grim<br />
1969 – C. S. Ross<br />
1970 – Paul F. Kerr<br />
1971 – Walter D. Keller<br />
1972 – G. W. Brindley<br />
1975 – William F. Bradley<br />
1975 – Sturges W. Bailey<br />
1975 – Jose J. Fripiat<br />
1977 – M. L. Jackson<br />
1979 – Toshio Sudo<br />
1980 – Haydn H. Murray<br />
1984 – C. Edmund Marshall<br />
1985 – Charles E. Weaver<br />
1988 – Max M. Mortland<br />
1989 – R. C. Reynolds, Jr.<br />
1990 – Joe L. White<br />
1990 – John Hower<br />
1991 – Joe B. Dixon<br />
1992 – Philip F. Low<br />
1993 – Thomas J. Pinnavaia<br />
1995 – W. D. Johns<br />
1996 – Victor A. Drits<br />
1997 – Udo Schwertmann<br />
1998 – Brij L. Sawhney<br />
2000 – Boris B. Zvyagin<br />
2001 – Keith Norrish<br />
2002 – Gerhard Lagaly<br />
2004 – Benny K. G. Theng<br />
2005 – M. Jeff Wilson<br />
2006 – Frederick J. Wicks<br />
2007 – no award made<br />
2008 – Norbert Clauer<br />
2009 – Joseph W Stucki<br />
2010 – J. M. Serratosa<br />
2011 – Sridhar Komarneni<br />
2012 – Akihiko Yamagishi<br />
2013 – Stephen Guggenheim<br />
2014 – no award made<br />
2015 – James Kirkpatrick<br />
2016 – Lisa Heller-Kallai<br />
2018 – Gordon "Jock" Churchman<br />
2019 – Dennis D. Eberl<br />
2020 – Eduardo Ruiz-Hitzky<br/>
2021 – David L. Bish<br/> | 0 | Theoretical and Fundamental Chemistry |
Consider a line of atoms A-O-B, separated by distance a. Rotate the entire row by θ = +2π/n and θ = −2π/n, with point O kept fixed. After the rotation by +2π/n, A is moved to the lattice point C and after the rotation by -2π/n, B is moved to the lattice point D. Due to the assumed periodicity of the lattice, the two lattice points C and D will be also in a line directly below the initial row; moreover C and D will be separated by r = ma, with m an integer. But by trigonometry, the separation between these points is:
Equating the two relations gives:
This is satisfied by only n = 1, 2, 3, 4, 6. | 0 | Theoretical and Fundamental Chemistry |
Acoustic black holes were first theorized to be useful by William Unruh in 1981. However, the first black hole analogue was not created in a laboratory until 2009. It was created in a rubidium Bose–Einstein condensate using a technique called density inversion. This technique creates a flow by repelling the condensate with a potential minimum. The surface gravity and temperature of the sonic black hole were measured, but no attempt was made to detect Hawking radiation. However, the scientists who created it predicted that the experiment was suitable for detection and suggested a method by which it might be done by lasing the phonons. In 2014, stimulated Hawking radiation was reported in an analogue black-hole laser by the same researchers. Quantum, spontaneous Hawking radiation was observed later.
A rotating sonic black hole was used in 2010 to give the first laboratory testing of superradiance, a process whereby energy is extracted from a black hole. | 1 | Applied and Interdisciplinary Chemistry |
Histidine phosphotransfer domains and histidine phosphotransferases (both often abbreviated HPt) are protein domains involved in the "phosphorelay" form of two-component regulatory systems. These proteins possess a phosphorylatable histidine residue and are responsible for transferring a phosphoryl group from an aspartate residue on an intermediate "receiver" domain, typically part of a hybrid histidine kinase, to an aspartate on a final response regulator. | 1 | Applied and Interdisciplinary Chemistry |
Viability PCR, also named v-PCR or vPCR, is an evolution of PCR. Through the use of a simple pre-treatment of the sample by the means of specific intercalating photo-reactive reagents it's possible to neutralize the DNA of dead cells. As a result, only DNA from live cells will be detected by PCR. This approach expands a lot the analytical scope of PCR procedures. The capability to detect only living cells become very important, because in key applications is more important to know the amount of live cells, than the total cell level. Examples of this are: food and water quality control, infectious diseases diagnostic, veterinary applications, ecological dynamics...
The first referenced work about this analytical approach was in 2003, Norwegian researchers suggest the use of Ethidium Monoazide, an azide form of Ethidium Bromide, which was used in other analytical fields as Flow Cytometry as a candidate for viability PCR. However, the main important advances were done by Nocker and colleagues, which demonstrated in successive works the potential of this technology and also suggested Propidium monoazide as a better reagent for vPCR.
This field still is in development, from 2003 up to 2015, the scientific evidences about the applicability of vPCR are stacking, nowadays main efforts are focused in procedure optimization. Since a simple reagent mix with the sample, photo-activation and subsequent PCR not always shows expected results, each procedure needs some optimization. Up to now the main improvements has been :
- Improving the efficiency of photo activation: early procedures were based on high power halogen lamps which overheated the samples and don't ensured constant light dose, these home made solutions have been replaced by led based instruments.[http://www.geniul.com/en/products/instruments/phast-blue-for-nucleic-acids-photo-labeling][https://www.qiagen.com/us/shop/sample-technologies/dna/dna-preparation/blu-v-system/]
- The use of long PCR amplicons as targets.
- The increase of temperature during dark incubation.
Through combining different optimizations strategies and controlling the analytical bias, nowadays the vPCR becomes a powerful analytical tool. | 1 | Applied and Interdisciplinary Chemistry |
Colored regions on Jupiters satellite Europa are thought to be tholins. The morphology of Europas impact craters and ridges is suggestive of fluidized material welling up from the fractures where pyrolysis and radiolysis take place. In order to generate colored tholins on Europa there must be a source of materials (carbon, nitrogen, and water), and a source of energy to drive the reactions. Impurities in the water ice crust of Europa are presumed both to emerge from the interior as cryovolcanic events that resurface the body, and to accumulate from space as interplanetary dust. | 0 | Theoretical and Fundamental Chemistry |
The Stokes approximation is developed from the Navier-Stokes equations by omission of the convective term. For small Reynolds numbers in the incompressible flow, this approximation is more useful. Then incompressible Navier Stokes equation can be written as-
Here linear diffusion term dominates the convection term.
In the stationary problem neglecting the convection term, we get-
Many theorems can be proved by using this process.
The main problem with the solution of the incompressible flow equation is the decoupling of the continuity and momentum equation due to the absence of pressure or density term. Chorin proposed the solution for this problem of the pressure decoupling; this approach is called artificial compressibility.
In the above equation stoke assume that at, non-stationary Navier Stokes problem converge towards the solution of the correspondent stationary problem. This solution will not depend upon the function .
If this is used for the above equation consisting of Navier stokes equation and continuity equations with time derivative of pressure, then the solution will be same as the stationary solution of the original Navier Stoke problem.
This process also introduce the new term artificial time as t→∞. Artificial compressibility method is combined with a dual time stepping procedure which involves iteration in pseudo-time within each physical time step. This guarantees a convergence towards the solution for the incompressible flow problem. | 1 | Applied and Interdisciplinary Chemistry |
Some insight into the evolution of mimetic color mimicry in Lepidoptera in particular can be seen through the study of the Optix gene. The Optix gene is responsible for the Heliconius butterflies signature red wing patterns that help it signal to predators that it is toxic. By sharing this coloration with other poisonous red winged butterflies the predator may have pursued previously, the Heliconius butterfly increases its chance of survival through association. By mapping the genome of many related species of Heliconius' butterflies "show[s] that the cis-regulatory evolution of a single transcription factor can repeatedly drive the convergent evolution of complex color patterns in distantly related species…". This suggests that the evolution of a non-coding piece of DNA that regulates the transcription of nearby genes can be the reason behind similar phenotypic coloration between distant species, making it hard to determine if the trait is homologous or simply the result of convergent evolution. | 1 | Applied and Interdisciplinary Chemistry |
Adding to the transition metal-bismuth carbonyl clusters, the dibismuth clusters with transition metals have also been explored by synthetic chemists. The core of such compounds is represented in the form of dibismuthene or dibismithyne unit, in which the Bi atoms contain the inert 6s lone pair and through π-bond-donation are able to coordinate to carbonyl moieties of transition metals .
The common synthetic precursor is the trimethylsilylmethyl-cyclobismuthane. Upon reaction with tungsten pentacarbonyl, the resulting side-on adduct preserved the dibismuthene unit, while reaction with diiron noncarbonyl yields the a tetracylic heteronuclear iron-bismuth carbonyl compound (see scheme to the right).
The complexity of the dibismuthene complexes ranges from incorporation of cobalt ions to generate a prismatic cobalto carbonyl dicapped structure in the [(CO)CoBi] structure to iron incorporation to yield diiron dibismuth tetracyclic moiety side-on capped with cobaltocarbonyl unit. A similar structure was synthesized with tungsten replacing the iron units and this time capped with a bismuth-iron carbonyl-Cp unit. Finally, another example comes in the form of a side-on coordinated zirconium dicyclopentadienyl unit to the dibismuth mesitylene moiety (see figure). | 0 | Theoretical and Fundamental Chemistry |
The following convection diffusion equation is considered here
In the above equation, four terms represents transience, convection, diffusion and a source term respectively, where
* is the temperature in particular case of heat transfer otherwise it is the variable of interest
* is time
* is the specific heat
* is velocity
* is porosity that is the ratio of liquid volume to the total volume
* is mass density
* is thermal conductivity
* is source term representing the capacity of internal sources
The equation above can be written in the form
where is the diffusion coefficient. | 1 | Applied and Interdisciplinary Chemistry |
Plants in the genus Humulus and Cannabis produce terpenophenolic metabolites, compounds that are meroterpenes. Phenolic lipids are long aliphatic chains bonded to a phenolic moiety. | 0 | Theoretical and Fundamental Chemistry |
Cold climates may present special challenges. Road salt contains chlorides that could migrate through the porous pavement into groundwater. Snow plow blades could catch block edges of concrete pavers or other block installations, damaging surfaces and creating potholes. Sand cannot be used for snow and ice control on porous surfaces because it will plug the pores and reduce permeability. Although there are design modifications to reduce the risks, infiltrating runoff may freeze below the pavement, causing frost heave. Another issue is spalling damage, which exclusively occurs on porous concrete pavement from salt application during the winter season. Thus porous paving is suggested for warmer climates. However, other materials have proven to be effective, even lowering winter maintenance costs by preserving salt in the pavement itself. This also reduces the amount of storm water runoff that is contaminated with salt chlorides. Pervious concrete and asphalt designed to reduce frost heave and spalling damage has been used successfully in Norway and New Hampshire. Furthermore, experience suggests that preventive measures with rapid drainage below porous surfaces be taken in order to increase the rate of snow melt above ground. | 1 | Applied and Interdisciplinary Chemistry |
The latent image captured in the glass is made visible by heating. This heat treatment is done by raising the temperature to about 500 °C to allow the oxidation-reduction reaction to form silver nanoclusters. Following this, the temperature is raised to 550–560 °C and lithium metasilicate (LiSiO) forms on the silver nanoclusters. This material forms in the crystalline phase. | 0 | Theoretical and Fundamental Chemistry |
Computer Atlas of Surface Topography of Proteins (CASTp) aims to provide comprehensive and detailed quantitative characterization of topographic features of protein, is now updated to version 3.0. Since its release in 2006, the CASTp server has ≈45000 visits and fulfills ≈33000 calculation requests annually. CASTp has been proven as a confident tool for a wide range of researches, including investigations of signaling receptors, discoveries of cancer therapeutics, understanding of mechanism of drug actions, studies of immune disorder diseases, analysis of protein–nanoparticle interactions, inference of protein functions and development of high-throughput computational tools. This server is maintained by Jie Liang's lab in University of Illinois at Chicago. | 1 | Applied and Interdisciplinary Chemistry |
Since 1 January 2010, it has been illegal to use newly manufactured HCFCs to service refrigeration and air-conditioning equipment; only reclaimed and recycled HCFCs may be used. In practice this means that the gas has to be removed from the equipment before servicing and replaced afterwards, rather than refilling with new gas.
Since 1 January 2015, it has been illegal to use any HCFCs to service refrigeration and air-conditioning equipment; broken equipment that used HCFC refrigerants must be replaced with equipment that does not use them. | 1 | Applied and Interdisciplinary Chemistry |
In 1957, Marks married sculptor and artist Averil Sherrard and had two children. Marks was known to have been an atheist and a humanist who was opposed to religion. Along with his wife, he campaigned for various causes including saving a park in Guildford, Surrey, where they lived, from developers. His brother John Marks was also a doctor, and the chair of the British Medical Association.
Marks died on 6 November 2023, at the age of 93. | 1 | Applied and Interdisciplinary Chemistry |
The breakdown of DNA and RNA is occurring continuously in the cell. Purine and pyrimidine nucleosides can either be degraded to waste products and excreted or can be salvaged as nucleotide components. | 1 | Applied and Interdisciplinary Chemistry |
The term "quantitative analysis" is often used in comparison (or contrast) with "qualitative analysis", which seeks information about the identity or form of substance present. For instance, a chemist might be given an unknown solid sample. They will use "qualitative" techniques (perhaps NMR or IR spectroscopy) to identify the compounds present, and then quantitative techniques to determine the amount of each compound in the sample. Careful procedures for recognizing the presence of different metal ions have been developed, although they have largely been replaced by modern instruments; these are collectively known as qualitative inorganic analysis. Similar tests for identifying organic compounds (by testing for different functional groups) are also known.
Many techniques can be used for either qualitative or quantitative measurements. For instance, suppose an indicator solution changes color in the presence of a metal ion. It could be used as a qualitative test: does the indicator solution change color when a drop of sample is added? It could also be used as a quantitative test, by studying the color of the indicator solution with different concentrations of the metal ion. (This would probably be done using ultraviolet-visible spectroscopy.) | 0 | Theoretical and Fundamental Chemistry |
When H and OH ions are not involved in the reaction, the boundary line is horizontal and independent of pH. <br />The reaction equation is thus written:
As, the standard Gibbs free energy :
Using the definition of the electrode potential ∆G = -zFE, where F is the Faraday constant, this may be rewritten as a Nernst equation:
or, using base-10 logarithms:
For the equilibrium /, taken as example here, considering the boundary line between Fe and Fe, the half-reaction equation is:
Since H ions are not involved in this redox reaction, it is independent of pH.
E = 0.771 V with only one electron involved in the redox reaction.
The potential E is a function of temperature via the thermal voltage and directly depends on the ratio of the concentrations of the and ions:
For both ionic species at the same concentration (e.g., ) at STP, log 1 = 0, so, , and the boundary will be a horizontal line at E = 0.771 volts. The potential will vary with temperature. | 0 | Theoretical and Fundamental Chemistry |
Non-B DB is a database integrating annotations and analysis of non-B DNA-forming sequence motifs. The database provides alternative DNA structure predictions including Z-DNA motifs, quadruplex-forming motifs, inverted repeats, mirror repeats and direct repeats and their associated subsets of cruciforms, triplex and slipped structures, respectively. | 0 | Theoretical and Fundamental Chemistry |
Sala wrote his works in French and Italian, but most appeared translated in German, French and Latin editions. In them, he relied on practical-experimental foundations. In his late work, he distanced himself from Paracelsus.
* Medico-chemical works
** [https://www.digitale-sammlungen.de/de/view/bsb11219458?page=3 Joh. Beyer, Frankfurt 1647 (digital copy)]
** [https://www.digitale-sammlungen.de/de/view/bsb10054968?page=9 Berthelin, Rouen 1650 (digital copy)]
** [https://www.digitale-sammlungen.de/de/view/bsb10050845?page=7 Hermann a Sande, Frankfurt 1682 (digital copy)] | 1 | Applied and Interdisciplinary Chemistry |
WaterGuard manufactured by Aquatain advertises a polymer based material that reduces water evaporation.
Other products include Solarpill and Water$aver. The efficacy of these products has not been shown. | 0 | Theoretical and Fundamental Chemistry |
A test is done by taking a small scraping from a pill and placing it in the reagent testing liquid or dropping the reagent onto the scraping. The liquid will change colour when reacting with different chemicals to indicate the presence of certain substances.
Testing with a reagent kit does not indicate the pill is safe. While the testing process does show some particular substances are present, it may not show a harmful substance that is also present and unaccounted for by the testing process. Some substances that cause strong colour changes can also mask the presence of other substances that cause weaker colour changes. Thin layer chromatography is used with reagent testing to separate substances before testing and prevent this "masking" effect.
Ehrlich reagent can only detect drugs with an indole moiety, but this is useful because drugs from the NBOMe class do not have an indole and are often sold as LSD which does. The Ehrlich reagent has an additional benefit over other reagents in that it does not react with the paper on which LSD is often distributed.
Reagent tests are often limited to target specific chemicals, and when these substances are mis-sold it is usually by substitution of a different substance in the same chemical family, rendering the test unuseful for consumers. However, reagent tests for chemicals families also exist.
Lacing agents are often used to cut the weight of substances. Some of the most available and non-suspicious cutting agents are reducing sugars: The common dietary monosaccharides galactose, glucose and fructose are all reducing sugars. Sugar is the generic name for sucrose, a disaccharide composed of glucose and fructose. | 0 | Theoretical and Fundamental Chemistry |
Hydrophobicity scales are values that define the relative hydrophobicity or hydrophilicity of amino acid residues. The more positive the value, the more hydrophobic are the amino acids located in that region of the protein. These scales are commonly used to predict the transmembrane alpha-helices of membrane proteins. When consecutively measuring amino acids of a protein, changes in value indicate attraction of specific protein regions towards the hydrophobic region inside lipid bilayer.
The hydrophobic or hydrophilic character of a compound or amino acid is its hydropathic character, hydropathicity, or hydropathy. | 0 | Theoretical and Fundamental Chemistry |
Theory and instrumentation of Raman/AFM and IR/AFM combine the theory of SPR (AFM and NSOM) and Raman scattering, and this combination is based on TERS. In TERS, the electric field of excitation source induces an SPR in the tip of the probe. If the electric field vector of the incidence light is perpendicular (s-polarized) to the metal tip axis, the free electrons are driven to the sides lateral of the tip. If it is parallel (p-polarized) to the tip axis, the free electrons on the surface of the metal are confined to the end of the apex of tip. As a consequence, there is a very large electric-field enhancement which is sensed by the molecules close to it leading to a stronger signal.
A typical approach in a TERS experiment is to focus the laser beam on a metal tip with the light polarized along the tip axis, followed by collection of the surface-enhanced Raman scattered light from the sample in the enhancement zone of the tip using optics.
Depending on the sample and experiment, different illumination geometries have been applied in TERS experiments, as shown in figure 4. With p-polarized (parallel to the surface normal) incidence light, the plasmon excitation at the tip is most efficient. If the focusing objective lens is also used for collecting the scattered photons (backscattering geometry), the optimum angle is around 55° with respect to the surface normal. This is because the scattering lobe is maximum with this configuration and it provides a much enhanced signal. The setup of figure 4(A) is usually used for the large thick samples. Setup (B) handles semi-transparent or transparent samples, such as single cells, tissue samples and biopolymers. The setup of figure 4(C) is preferred for opaque samples because all the light would be focused by the parabolic mirror. | 0 | Theoretical and Fundamental Chemistry |
Kortüm was a physical chemist who had a broad range of interests, and published prolifically. His research covered many aspects of light scattering. He began to pull together what was known in various fields into an understanding of how “reflectance spectroscopy” worked. In 1969, the English translation of his book entitled Reflectance Spectroscopy (long in preparation and translation) was published. This book came to dominate thinking of the day for 20 years in the emerging fields of both DRIFTS and NIR Spectroscopy.
Kortüms position was that since regular (or specular) reflection is governed by different laws than diffuse reflection, they should therefore be accorded different mathematical treatments. He developed an approach based on Schusters work by ignoring the emissivity of the clouds in the "foggy atmosphere". If we take as the fraction of incident light absorbed and as the fraction scattered isotropically by a single particle (referred to by Kortüm as the "true coefficients of single scatter"), and define the absorption and isotropic scattering for a layer as and then:
This is the same "remission function" as used by Judd, but Kortüm's translator referred to it as "the so-called reflectance function". If we substitute back for the particle properties, we obtain and then we obtain the Schuster equation for isotropic scattering:
Additionally, Kortüm derived "the Kubelka-Munk exponential solution" by defining and as the absorption and scattering coefficient per centimeter of the material and substituting: and , while pointing out in a footnote that is a back-scattering coefficient. He wound up with what he called the "Kubelka–Munk function", commonly called the Kubelka–Munk equation:
Kortüm concluded that "the two constant theory of Kubelka and Munk leads to conclusions accessible to experimental test. In practice these are found to be at least qualitatively confirmed, and suitable conditions fulfilling the assumptions made, quantitatively as well."
Kortüm tended to eschew the "particle theories", though he did record that one author, N.T. Melamed of Westinghouse Research Labs, "abandoned the idea of plane parallel layers and substituted them with a statistical summation over individual particles." | 0 | Theoretical and Fundamental Chemistry |
Phred quality scores are logarithmically related to the base-calling error probabilities and defined as
This relation can also be written as
For example, if Phred assigns a quality score of 30 to a base, the chances that this base is called incorrectly are 1 in 1000.
The phred quality score is the negative ratio of the error probability to the reference level of expressed in Decibel (dB). | 1 | Applied and Interdisciplinary Chemistry |
Media filters are used in drinking water treatment, where multimedia filters are used as a primary or secondary filtration step to remove a wider range of particle sizes and types than sand filters, including organic matter and smaller particles.
Municipal drinking water systems often use a rapid sand filter and/or a slow sand filter for purification. Silica sand is the most widely used medium in such filters. Anthracite coal, garnet sand, ilmenite, granular activated carbon, manganese green sand and crushed recycled glass are among the alternative filter media used. | 1 | Applied and Interdisciplinary Chemistry |
Catabolism () is the set of metabolic pathways that breaks down molecules into smaller units that are either oxidized to release energy or used in other anabolic reactions. Catabolism breaks down large molecules (such as polysaccharides, lipids, nucleic acids, and proteins) into smaller units (such as monosaccharides, fatty acids, nucleotides, and amino acids, respectively). Catabolism is the breaking-down aspect of metabolism, whereas anabolism is the building-up aspect.
Cells use the monomers released from breaking down polymers to either construct new polymer molecules or degrade the monomers further to simple waste products, releasing energy. Cellular wastes include lactic acid, acetic acid, carbon dioxide, ammonia, and urea. The formation of these wastes is usually an oxidation process involving a release of chemical free energy, some of which is lost as heat, but the rest of which is used to drive the synthesis of adenosine triphosphate (ATP). This molecule acts as a way for the cell to transfer the energy released by catabolism to the energy-requiring reactions that make up anabolism.
Catabolism is a destructive metabolism and anabolism is a constructive metabolism. Catabolism, therefore, provides the chemical energy necessary for the maintenance and growth of cells. Examples of catabolic processes include glycolysis, the citric acid cycle, the breakdown of muscle protein in order to use amino acids as substrates for gluconeogenesis, the breakdown of fat in adipose tissue to fatty acids, and oxidative deamination of neurotransmitters by monoamine oxidase. | 1 | Applied and Interdisciplinary Chemistry |
This compound may be prepared by reacting the corresponding sulfonic acid with excess phosphorus oxychloride (POCl) at room temperature. | 0 | Theoretical and Fundamental Chemistry |
It has been shown in previous studies that the only types of RNA editing seen in the plants mitochondria and plastids are conversion of C-to-U and U-to-C (very rare). RNA-editing sites are found mainly in the coding regions of mRNA, introns, and other non-translated regions. In fact, RNA editing can restore the functionality of tRNA molecules. The editing sites are found primarily upstream of mitochondrial or plastid RNAs. While the specific positions for C to U RNA editing events have been fairly well studied in both the mitochondrion and plastid, the identity and organization of all proteins comprising the editosome have yet to be established. Members of the expansive PPR protein family have been shown to function as trans'-acting factors for RNA sequence recognition. Specific members of the MORF (Multiple Organellar RNA editing Factor) family are also required for proper editing at several sites. As some of these MORF proteins have been shown to interact with members of the PPR family, it is possible MORF proteins are components of the editosome complex. An enzyme responsible for the trans- or deamination of the RNA transcript remains elusive, though it has been proposed that the PPR proteins may serve this function as well.
RNA editing is essential for the normal functioning of the plant's translation and respiration activity. Editing can restore the essential base-pairing sequences of tRNAs, restoring functionality. It has also been linked to the production of RNA-edited proteins that are incorporated into the polypeptide complexes of the respiration pathway. Therefore, it is highly probable that polypeptides synthesized from unedited RNAs would not function properly and hinder the activity of both mitochondria and plastids.
C-to-U RNA editing can create start and stop codons, but it cannot destroy existing start and stop codons. A cryptic start codon is created when the codon ACG is edited to be AUG. | 1 | Applied and Interdisciplinary Chemistry |
Any of the image correlation spectroscopy methods can also be performed on a spinning disk confocal microscope, which in practice can obtain faster imaging speeds compared to a laser scanning confocal microscope. This approach has recently been applied to diffusion in a spatially varying complex environment, producing a pixel resolution map of a diffusion coefficient. The spatial mapping of diffusion with FCS has subsequently been extended to the TIRF system. Spatial mapping of dynamics using correlation techniques had been applied before, but only at sparse points or at coarse resolution. | 0 | Theoretical and Fundamental Chemistry |
Enzymes that contain a catalytic triad use it for one of two reaction types: either to split a substrate (hydrolases) or to transfer one portion of a substrate over to a second substrate (transferases). Triads are an inter-dependent set of residues in the active site of an enzyme and act in concert with other residues (e.g. binding site and oxyanion hole) to achieve nucleophilic catalysis. These triad residues act together to make the nucleophile member highly reactive, generating a covalent intermediate with the substrate that is then resolved to complete catalysis. | 1 | Applied and Interdisciplinary Chemistry |
The human trace amine-associated receptors are a group of six G protein-coupled receptors (i.e., TAAR1, TAAR2, TAAR5, TAAR6, TAAR8, and TAAR9) that – with exception for TAAR1 – are expressed in the human olfactory epithelium. In humans and other animals, TAARs in the olfactory epithelium function as olfactory receptors that detect volatile amine odorants, including certain pheromones; these TAARs putatively function as a class of pheromone receptors involved in the olfactive detection of social cues.
A review of studies involving non-human animals indicated that TAARs in the olfactory epithelium can mediate attractive or aversive behavioral responses to a receptor agonist. This review also noted that the behavioral response evoked by a TAAR can vary across species (e.g., TAAR5 mediates attraction to trimethylamine in mice and aversion to trimethylamine in rats). In humans, hTAAR5 presumably mediates aversion to trimethylamine, which is known to act as an hTAAR5 agonist and to possess a foul, fishy odor that is aversive to humans; however, hTAAR5 is not the only olfactory receptor that is responsible for trimethylamine olfaction in humans. hTAAR5-mediated trimethylamine aversion has not been examined in published research. | 1 | Applied and Interdisciplinary Chemistry |
The raw materials are different paper pulps. The pulp may be from softwood, hardwood, fiber crops, mineral fibers. For high quality filters, dissolving pulp and mercerised pulp are used. Most filter papers are made using small paper machines. For laboratory filters, the machines may be as small as 50 cm in width. The paper is often crêped to improve porosity. The filter papers may also be treated with reagents or impregnation to get the right properties. | 0 | Theoretical and Fundamental Chemistry |
The nucleosome core particle (shown in the figure) consists of about 146 base pair of DNA wrapped in 1.67 left-handed superhelical turns around the histone octamer, consisting of 2 copies each of the core histones H2A, H2B, H3, and H4. Adjacent nucleosomes are joined by a stretch of free DNA termed linker DNA (which varies from 10 - 80 bp in length depending on species and tissue type).The whole structure generates a cylinder of diameter 11 nm and a height of 5.5 nm.
Nucleosome core particles are observed when chromatin in interphase is treated to cause the chromatin to unfold partially. The resulting image, via an electron microscope, is "beads on a string". The string is the DNA, while each bead in the nucleosome is a core particle. The nucleosome core particle is composed of DNA and histone proteins.
Partial DNAse digestion of chromatin reveals its nucleosome structure. Because DNA portions of nucleosome core particles are less accessible for DNAse than linking sections, DNA gets digested into fragments of lengths equal to multiplicity of distance between nucleosomes (180, 360, 540 base pairs etc.). Hence a very characteristic pattern similar to a ladder is visible during gel electrophoresis of that DNA. Such digestion can occur also under natural conditions during apoptosis ("cell suicide" or programmed cell death), because autodestruction of DNA typically is its role. | 1 | Applied and Interdisciplinary Chemistry |
The term "remineralization" is used in several contexts across different disciplines. The term is most commonly used in the medicinal and physiological fields, where it describes the development or redevelopment of mineralized structures in organisms such as teeth or bone. In the field of biogeochemistry, however, remineralization is used to describe a link in the chain of elemental cycling within a specific ecosystem. In particular, remineralization represents the point where organic material constructed by living organisms is broken down into basal inorganic components that are not obviously identifiable as having come from an organic source. This differs from the process of decomposition which is a more general descriptor of larger structures degrading to smaller structures.
Biogeochemists study this process across all ecosystems for a variety of reasons. This is done primarily to investigate the flow of material and energy in a given system, which is key to understanding the productivity of that ecosystem along with how it recycles material versus how much is entering the system. Understanding the rates and dynamics of organic matter remineralization in a given system can help in determining how or why some ecosystems might be more productive than others. | 0 | Theoretical and Fundamental Chemistry |
The Kröhnke methodology has also been utilized to generate a number of interesting metal-binding ligands since polypyridyl complexes such as bipyridine (bipy) have been used extensively as ligands. The Kröhnke synthesis was used to prepare a family of tetrahydroquinoline-based N, S-type ligands. 2-thiophenylacetophenone (36) was reacted with iodine gas and pyridine in quantitative yield to generate acylmethylpyridinium iodide 37. Reaction with a chiral cyclic α, β-unsaturated ketone derived from 2-(+)-carene yielded the desired N, S-type ligand 38.
Novel, chiral P, N-ligands have been prepared using the Kröhnke method. α-pyridinium acyl ketone salt 39 was cyclized with pinocarvone derivative 40 to generate pyridine 41. The benzylic position of 41 was methylated and subsequent SnAr reaction with potassium diphenylphosphide to generate ligand 42.
The Kröhnke reaction has also enjoyed applicability to the synthesis of a number of biologically active compounds in addition to ones cataloged in combinatorial studies. Kelly and co-workers developed a route to cyclo-2,2′:4′,4′′:2′′,2′′′:4′′′,4′′′′:2′′′′,2′′′′′:4′′′′′,4-sexipyridine utilizing the Kröhnke reactions as the key macrocyclization step. Polypyridine complex 43 was treated with N-Bromosuccinimide in wet tetrahydrofuran followed by pyridine to generate the acylmethylpyridinium salt 44 which can then undergo the macrocyclization under standard conditions to yield the desired product 45. The Kröhnke method in this synthesis was crucial due to the failure of other cyclization techniques such as the Glaser coupling or Ullmann coupling.
Another use of the Kröhnke pyridine synthesis was the generation of a number of 2,4,6-trisubstituted pyridines that were investigated as potential topoisomerase 1 inhibitors. 2-acetylthiophene (46) was treated with iodine and pyridine to generate α-pyridinium acyl ketone 47. Reaction with Michael acceptor 48 under standard conditions yielded functionalized pyridine 49 in 60% overall yield.
Ultimately, the Kröhnke pyridine synthesis offers a facile and straightforward approach to the synthesis of a wide breadth of functionalized pyridines and poly aryl systems. The Kröhnke methodology has been applied to a number of strategies towards interesting ligands and biologically relevant molecules. Additionally, the Kröhnke reaction and its variations offer a number of advantages than alternative methods to pyridine synthesis ranging from one-pot, organic solvent-free variations to high atom economy. | 0 | Theoretical and Fundamental Chemistry |
In the experiment, proflavin-induced mutations of the T4 bacteriophage gene, rIIB, were isolated. Proflavin causes mutations by inserting itself between DNA bases, typically resulting in insertion or deletion of a single base pair.
Through the use of proflavin, the experimenters were able to insert or delete base pairs into their sequence of interest. When nucleotides were inserted or deleted, the gene would often be nonfunctional. However, if three base pairs were added or deleted, the gene would remain functional. This proved that the genetic code uses a codon of three nucleotide bases that corresponds to an amino acid. The mutants produced by Crick and Brenner that could not produce functional rIIB protein were the results of frameshift mutations, where the triplet code was disrupted.
Brenner and Crick et al. were also able to correct their frameshift mutations through the use of proflavin. If they had a nonfunctional gene due to a deleted base pair, by inserting a base pair into the general area of the deleted one, they were able to rescue the function of the gene. This is because the bases were shifted back into the correct reading frame. | 1 | Applied and Interdisciplinary Chemistry |
In October 2016, astronomers reported that the methylidyne radical ⫶CH, the carbon-hydrogen positive ion :CH, and the carbon ion ⫶C are the result of ultraviolet light from stars, rather than in other ways, such as the result of turbulent events related to supernovas and young stars, as thought earlier. | 0 | Theoretical and Fundamental Chemistry |
In order to confirm the effectiveness and quality of the qPCR process that was performed, there are several actions and subsequent data that must be presented. This includes explaining the specific method of checking that the process functioned, such as using a gel, direct sequencing of the genetic material, showing a melt profile, or from digestion by restriction enzyme. If SYBR Green I was used, then the Cq of the control group with no template DNA must be given. Further essential data includes the calibration of the machine curves with the slope and y intercept noted, the efficiency of the PCR process as determined from the aforementioned slope, the correlation coefficients (r squared) for the calibration curves, the dynamic range of the linear curves, the Cq found at the lowest concentration where 95% of the results were still positive (LOD) along with the evidence for the LOD itself, and lastly if a multiplex is used, then the efficiency and LOD must be given for each assay done.
The extra desired information includes evidence given that qPCR optimization occurred by the use of gradients, the confidence intervals to show efficiency of the qPCR, and the confidence intervals for the entire range tested. | 1 | Applied and Interdisciplinary Chemistry |
In statistical physics, a system is said to present quenched disorder when some parameters defining its behavior are random variables which do not evolve with time. These parameters are said to be quenched or frozen. Spin glasses are a typical example. Quenched disorder is contrasted with annealed disorder in which the parameters are allowed to evolve themselves.
Mathematically, quenched disorder is more difficult to analyze than its annealed counterpart as averages over thermal noise and quenched disorder play distinct roles. Few techniques to approach each are known, most of which rely on approximations. Common techniques used to analyzed systems with quenched disorder include the replica trick, based on analytic continuation, and the cavity method, where a system's response to the perturbation due to an added constituent is analyzed. While these methods yield results agreeing with experiments in many systems, the procedures have not been formally mathematically justified. Recently, rigorous methods have shown that in the Sherrington-Kirkpatrick model, an archetypal spin glass model, the replica-based solution is exact. The generating functional formalism, which relies on the computation of path integrals, is a fully exact method but is more difficult to apply than the replica or cavity procedures in practice. | 0 | Theoretical and Fundamental Chemistry |
Pre-bioprinting is the process of creating a model that the printer will later create and choosing the materials that will be used. One of the first steps is to obtain a biopsy of the organ, to sample cells. Common technologies used for bioprinting are computed tomography (CT) and magnetic resonance imaging (MRI). To print with a layer-by-layer approach, tomographic reconstruction is done on the images. The now-2D images are then sent to the printer to be made. Once the image is created, certain cells are isolated and multiplied. These cells are then mixed with a special liquefied material that provides oxygen and other nutrients to keep them alive. This aggregation of cells does not require a scaffold, and is required for placing in the tubular-like tissue fusion for processes such as extrusion. | 1 | Applied and Interdisciplinary Chemistry |
In fluid dynamics, the Hadamard–Rybczynski equation gives the terminal velocity of slowly moving spherical bubble through an ambient fluid. It is named after Jacques Hadamard and Witold Rybczynski:
where
* is the radius of the bubble.
* the gravitational acceleration.
* the density of the bubble.
* the density of the ambient fluid.
* the viscosity of the bubble.
* the viscosity of the ambient fluid.
* the resultant velocity of the bubble.
The Hadamard–Rybczynski equation can be derived from the Navier–Stokes equations by considering only the buoyancy force and drag force acting on the moving bubble. The surface tension force and inertia force of the bubble are neglected. | 1 | Applied and Interdisciplinary Chemistry |
Feedwater pumps range in size up to many kilowatts and the electric motor is usually separated from the pump body by some form of mechanical coupling. Large industrial condensate pumps may also serve as the feedwater pump. In either case, to force the water into the boiler, the pump must generate sufficient pressure to overcome the steam pressure developed by the boiler. This is usually accomplished through the use of a centrifugal pump.
Another common form of feedwater pump runs constantly and is provided with a minimum flow device to stop overpressuring the pump on low flows. The minimum flow usually returns to the tank or deaerator. | 1 | Applied and Interdisciplinary Chemistry |
Axel Fredrik Cronstedt was born on 23 December 1722 on the estate of Ströpsta, in Sudermania.
His father, Gabriel Olderman Cronstedt (1670–1757), was a military engineer.
His mother, Maria Elizabeth Adlersberg, was Gabriel Cronstedt's second wife.
Beginning in 1738, Axel Cronstedt was an unregistered student at the University of Uppsala, hearing lectures with Johan Gottschalk Wallerius (1709–1785), professor of chemistry, and astronomer Anders Celsius (1701–1744). At Uppsala, he became a friend of Sven Rinman, discoverer of Rinman's green.
In 1743, during an unstable period politically, Cronstedt left Uppsala to act as his father's secretary on a military tour of inspection. This tour strengthened his interest in mines and mineralogy.
Cronstedt entered the School of Mines where his instructors included geologist Daniel Tilas (1712-1772). On Tilas' recommendation, Cronstedt went on mining tours in the summers of 1744 and 1745. In 1746, he surveyed copper mines.
From 1746 to 1748 Cronstedt took classes with George Brandt, the discoverer of cobalt, at the royal mining laboratory in Stockholm, the Laboratorium Chemicum. There he studied chemical analysis and smelting.
Between 1748, when he completed his studies, and 1758, Cronstedt held a variety of positions. In 1756, he was disappointed to be passed over for a position at the Bureau of Mines, but in 1758, he became a superintendent of mining operations for the mining districts of Öster and Västerbergslagen.
In 1760 Cronstedt married Gertrud Charlotta Söderhielm (1728–1769). In 1761, he moved to the estate of Nisshytte, north of Riddarhyttan. He died there on 19 August 1765. | 1 | Applied and Interdisciplinary Chemistry |
Closely tied with the field of biotechnology, this subject of cell engineering employs recombinant DNA methods to induce cells to construct a desired product such as a protein, antibody, or enzyme. One of the most notable examples of this subset of cellular engineering is the transformation of E. Coli to transcript and translate a precursor to insulin which drastically reduced the cost of production. Similar research was conducted shortly after in 1979 in which E. Coli was transformed to express human growth hormone for use in treatment of pituitary dwarfism. Finally, much progress has been made in engineering cells to produce antigens for the purpose of creating vaccines. | 1 | Applied and Interdisciplinary Chemistry |
When operating, the Mount Polley mine moves 80,000–90,000 tonnes of material per day from the mine. This contains 20,000 tonnes of ore.
Mount Polley does not require high-skilled labour for operations and hires and trains from the local communities of Big Lake, Horsefly and as far away as Quesnel and Williams Lake. Most workers come from communities near the mine. | 1 | Applied and Interdisciplinary Chemistry |
The rapid economic growth, industrialization and urbanization are associated with a strong increase in energy demand and emissions of air pollutants including sulfur dioxide (see also acid rain) and hydrogen sulfide, which may affect plant metabolism. Sulfur gases are potentially phytotoxic, however, they may also be metabolized and used as sulfur source and even be beneficial if the sulfur fertilization of the roots is not sufficient.
Plant shoots form a sink for atmospheric sulfur gases, which can directly be taken up by the foliage (dry deposition). The foliar uptake of sulfur dioxide is generally directly dependent on the degree of opening of the stomates, since the internal resistance to this gas is low. Sulfite is highly soluble in the apoplastic water of the mesophyll, where it dissociates under formation of bisulfite and sulfite.
Sulfite may directly enter the sulfur reduction pathway and be reduced to sulfide, incorporated into cysteine, and subsequently into other sulfur compounds. Sulfite may also be oxidized to sulfate, extra- and intracellularly by peroxidases or non-enzymatically catalyzed by metal ions or superoxide radicals and subsequently reduced and assimilated again. Excessive sulfate is transferred into the vacuole; enhanced foliar sulfate levels are characteristic for exposed plants.
The foliar uptake of hydrogen sulfide appears to be directly dependent on the rate of its metabolism into cysteine and subsequently into other sulfur compounds. There is strong evidence that O-acetyl-serine (thiol)lyase is directly responsible for the active fixation of atmospheric hydrogen sulfide by plants.
Plants are able to transfer from sulfate to foliar absorbed atmospheric sulfur as sulfur source and levels of 60 ppb or higher appear to be sufficient to cover the sulfur requirement of plants. There is an interaction between atmospheric and pedospheric sulfur utilization. For instance, hydrogen sulfide exposure may result in a decreased activity of APS reductase and a depressed sulfate uptake. | 1 | Applied and Interdisciplinary Chemistry |
Benzene is considered a light aromatic hydrocarbon with high solubility and high volatility. It is unclear how temperature and depth would impact the volatility of benzene, so assumptions have been made that benzene in oil (1% weight by volume) would not volatilize before equilibrating with water.
Using the octanol-water partition coefficient and a 100-year precipitation event for the area, a worst-case estimate of 75 mg/L of benzene is anticipated to flow toward the aquifer. The actual movement of the plume through groundwater systems is not well described, although one estimate is that up to 4.9 billion gallons of water in the Ogallala Aquifer could become contaminated with benzene at concentrations above the MCL. The Final Environmental Impact Statement from the State Department does not include a quantitative analysis because it assumed that most benzene will volatilize. | 1 | Applied and Interdisciplinary Chemistry |
Purely decorative work is rare among Minoan bronzes, and is comparatively poor in quality. There are several statuettes, very completely modelled but roughly cast; they are solid and unchased, with blurred details. Well known are a figure of a praying or dancing woman from the Troad, now at Berlin, and another from Hagia Triada; praying men from Tylissos and Psychro, another in the British Museum, a flute-player at Leyden, and an ambitious group of a man turning a somersault over a charging bull, known as the Minoan Bull-leaper. This last was perhaps a weight; there are smaller Mycenaean weights in the forms of animals, filled with lead, from Rhodes and Cyprus. Among the latest Mycenaean bronzes found in Cyprus are several tripod-stands of simple openwork construction, a type that has also been found with transitional material in Crete and in Early Iron Age (Geometric) contexts on the Greek mainland. Some more elaborate pieces, cast in designs of ships and men and animals, belong to a group of bronzes found in the Idaean cave in Crete, most of which are Asiatic works of the 9th or 8th centuries BC. The openwork tripods may have had the same origin. They are probably not Greek. | 1 | Applied and Interdisciplinary Chemistry |
Non-expendable mold casting differs from expendable processes in that the mold need not be reformed after each production cycle. This technique includes at least four different methods: permanent, die, centrifugal, and continuous casting. This form of casting also results in improved repeatability in parts produced and delivers near net shape results. | 1 | Applied and Interdisciplinary Chemistry |
A spectroradiometer is a light measurement tool that is able to measure both the wavelength and amplitude of the light emitted from a light source. Spectrometers discriminate the wavelength based on the position the light hits at the detector array allowing the full spectrum to be obtained with a single acquisition. Most spectrometers have a base measurement of counts which is the un-calibrated reading and is thus impacted by the sensitivity of the detector to each wavelength. By applying a calibration, the spectrometer is then able to provide measurements of spectral irradiance, spectral radiance and/or spectral flux. This data is also then used with built in or PC software and numerous algorithms to provide readings or Irradiance (W/cm2), Illuminance (lux or fc), Radiance (W/sr), Luminance (cd), Flux (Lumens or Watts), Chromaticity, Color Temperature, Peak and Dominant Wavelength. Some more complex spectrometer software packages also allow calculation of PAR μmol/m/s, Metamerism, and candela calculations based on distance and include features like 2- and 20-degree observer, baseline overlay comparisons, transmission and reflectance.
Spectrometers are available in numerous packages and sizes covering many wavelength ranges. The effective wavelength (spectral) range of a spectrometer is determined not only by the grating dispersion ability but also depends on the detectors sensitivity range. Limited by the semiconductors band gap the silicon-based detector responds to 200-1100 nm while the InGaAs based detector is sensitive to 900-1700 nm (or out to 2500 nm with cooling).
Lab/Research spectrometers often cover a broad spectral range from UV to NIR and require a PC. There are also IR Spectrometers that require higher power to run a cooling system. Many Spectrometers can be optimized for a specific range i.e. UV, or VIS and combined with a second system to allow more precise measurements, better resolution, and eliminate some of the more common errors found in broadband system such as stray light and lack of sensitivity.
Portable devices are also available for numerous spectral ranges covering UV to NIR and offer many different package styles and sizes. Hand held systems with integrated displays typically have built in optics, and an onboard computer with pre-programmed software. Mini spectrometers are also able to be used hand held, or in the lab as they are powered and controlled by a PC and require a USB cable. Input optics may be incorporated or are commonly attached by a fiber optic light guide. There are also micro Spectrometers smaller than a quarter that can be integrated into a system, or used stand alone. | 0 | Theoretical and Fundamental Chemistry |
As the reaction proceeds with the passage of time, the species' activities, and hence the reaction quotient, change in a way that reduces the free energy of the chemical system. The direction of the change is governed by the Gibbs free energy of reaction by the relation
where K is a constant independent of initial composition, known as the equilibrium constant. The reaction proceeds in the forward direction (towards larger values of Q) when ΔG ) when ΔG > 0. Eventually, as the reaction mixture reaches chemical equilibrium, the activities of the components (and thus the reaction quotient) approach constant values. The equilibrium constant is defined to be the asymptotic value approached by the reaction quotient:
: and .
The timescale of this process depends on the rate constants of the forward and reverse reactions. In principle, equilibrium is approached asymptotically at t → ∞; in practice, equilibrium is considered to be reached, in a practical sense, when concentrations of the equilibrating species no longer change perceptibly with respect to the analytical instruments and methods used.
If a reaction mixture is initialized with all components having an activity of unity, that is, in their standard states, then
: and .
This quantity, ΔG°, is called the standard Gibbs free energy of reaction.
All reactions, regardless of how favorable, are equilibrium processes, though practically speaking, if no starting material is detected after a certain point by a particular analytical technique in question, the reaction is said to go to completion. | 0 | Theoretical and Fundamental Chemistry |
When absorption was measured against wavelength at various pH values, the changes at wavelength 408 nm and 470 nm yielded a sigmoidal line with a midpoint at 5.1. This indicated that the absorbance at these two wavelengths depends upon the ionization of the chromophoric portion of TNP-ATP and is unaffected by ionization of ATP. Although this ionization constant of 5.1 is not in physiological range, it has been shown that the absorbance of TNP-ATP is sensitive enough to detect changes due to slight shifts in neutral pH. Spectroscopic superposition indicated TNP-ATP’s isosbestic point to be 339 nm. | 0 | Theoretical and Fundamental Chemistry |
Transposons vary in their structure and manner of proliferation, both of which help to define their classification. Each class contains autonomous elements, a sub-variety distinguished by the ability to self-proliferate, and also non-autonomous elements, which lack that ability. | 1 | Applied and Interdisciplinary Chemistry |
PPARGC1A has been shown to interact with:
* CREB-binding protein
* Estrogen-related receptor alpha (ERRα), estrogen-related receptor beta (ERR-β), estrogen-related receptor gamma (ERR-γ).
* Farnesoid X receptor
* FBXW7
* MED1, MED12, MED14, MED17,
* NRF1
* Peroxisome proliferator-activated receptor gamma
* Retinoid X receptor alpha
* Thyroid hormone receptor beta
ERRα and PGC-1α are coactivators of both glucokinase (GK) and SIRT3, binding to an ERRE element in the GK and SIRT3 promoters. | 1 | Applied and Interdisciplinary Chemistry |
Abū Yūsuf Yaʻqūb ibn ʼIsḥāq aṣ-Ṣabbāḥ al-Kindī (; ; ; ) was an Arab Muslim polymath active as a philosopher, mathematician, physician, and music theorist. Al-Kindi was the first of the Islamic peripatetic philosophers, and is hailed as the "father of Arab philosophy".
Al-Kindi was born in Kufa and educated in Baghdad. He became a prominent figure in the House of Wisdom, and a number of Abbasid Caliphs appointed him to oversee the translation of Greek scientific and philosophical texts into the Arabic language. This contact with "the philosophy of the ancients" (as Hellenistic philosophy was often referred to by Muslim scholars) had a profound effect on him, as he synthesized, adapted and promoted Hellenistic and Peripatetic philosophy in the Muslim world. He subsequently wrote hundreds of original treatises of his own on a range of subjects ranging from metaphysics, ethics, logic and psychology, to medicine, pharmacology, mathematics, astronomy, astrology and optics, and further afield to more practical topics like perfumes, swords, jewels, glass, dyes, zoology, tides, mirrors, meteorology and earthquakes.
In the field of mathematics, al-Kindi played an important role in introducing Hindu numerals to the Islamic world, and their further development into Arabic numerals along with al-Khwarizmi which eventually was adopted by the rest of the world. Al-Kindi was also one of the fathers of cryptography. Building on the work of al-Khalil (717–786), Al-Kindis book entitled Manuscript on Deciphering Cryptographic Messages' gave rise to the birth of cryptanalysis, was the earliest known use of statistical inference, and introduced several new methods of breaking ciphers, notably frequency analysis. He was able to create a scale that would enable doctors to gauge the effectiveness of their medication by combining his knowledge of mathematics and medicine.
The central theme underpinning al-Kindi's philosophical writings is the compatibility between philosophy and other "orthodox" Islamic sciences, particularly theology, and many of his works deal with subjects that theology had an immediate interest in. These include the nature of God, the soul and prophetic knowledge. | 1 | Applied and Interdisciplinary Chemistry |
Andreas Lüttge is Professor of Earth Science and Professor of Chemistry at Rice University in Houston, Texas (USA). He was also director of the National Corrosion Center (NCC) until 2010. The primary concerns of his research are surface chemical processes at minerals and rocks from low-temperature conditions up to the pressure and temperature conditions throughout the Earth's crust.
Andreas Luttge’s degrees are a Habilitation [venia legendi] (1995) and a PhD [Dr. rer. nat.] (1990) from the University of Tübingen (Germany). In 1995 the Alexander von Humboldt Foundation awarded a Feodor Lynen fellowship to Andreas Luttge to visit Yale University and to work with Prof. A.C. Lasaga.
Luttge published numerous studies about the surface dynamics of minerals, glasses and metals, including investigations of microbial activity at interfaces. He applies various experimental techniques using Vertical Scanning Interferometry, Electron and Atomic Force Microscopy and modeling techniques like Monte Carlo and ab initio methods. Resulting quantitative kinetic rate data are key prerequisites to provide a better understanding of the dynamics governing many geologic and technologic processes. | 0 | Theoretical and Fundamental Chemistry |
He was born in 1616 at Broughton, near Banbury, Oxfordshire. He obtained a B.A. degree from Oxford University in 1637 and an M.A. in 1640, qualifying as a physician with an MD in 1648. He died in 1657 near Boulogne while serving as a physician to the English army. He left a widow, Mary, and a son, John.
He lived at a time when the new science of chemistry was developing from alchemy and was an enthusiast for its application to medicine. He was known for his extensive knowledge of chemistry and was respected by scientists of the time such as Robert Boyle. | 1 | Applied and Interdisciplinary Chemistry |
On long timescales, atmospheric concentration is determined by the balance among geochemical processes including organic carbon burial in sediments, silicate rock weathering, and volcanic degassing. The net effect of slight imbalances in the carbon cycle over tens to hundreds of millions of years has been to reduce atmospheric . On a timescale of billions of years, such downward trend appears bound to continue indefinitely as occasional massive historical releases of buried carbon due to volcanism will become less frequent (as earth mantle cooling and progressive exhaustion of internal radioactive heat proceed further). The rates of these processes are extremely slow; hence they are of no relevance to the atmospheric concentration over the next hundreds or thousands of years. | 1 | Applied and Interdisciplinary Chemistry |
In 2002, Israel agreed to buy 1.75 billion cubic feet of water from Turkey every year for a period of 20 years. The method of transport involved the use of large plastic bubbles that would bring the water to the storage facility. In regards to the talks, the foreign minister of Turkey declared that this agreement will increase the cooperation between the two countries and also lead to peace and stability in the Middle East. Economically Israel concluded that the cost of importing water would be higher than choosing the desalinization option but chose to import anyway. In addition to hoping to achieve peace the foreign minister also mentioned that the landmark agreement turns water into an internationally accepted commodity, and that Turkey hopes to sell water to other countries. Turkey canceled the deal after the Gaza Flotilla Raid by IDF commandos Gaza Flotilla Raid on May 31 2010. During this incident several Turkish nationals were killed by Israeli armed forces. | 1 | Applied and Interdisciplinary Chemistry |
Ractopamine has not been allowed in the European Union, based on the 2009 EUs Food Safety Authoritys opinion on its safety evaluation, which concluded that available data were insufficient to derive a maximum residue limit as a safe residue level for human consumption. The uncertainty was particularly great for people who might be thought to be more susceptible than most to an increase in β adrenergic stimulation from consuming the additive, such as children or people with cardiovascular disease, and that simply increasing the "uncertainty factor" built into the calculation as a safety factor would rapidly become arbitrary. | 0 | Theoretical and Fundamental Chemistry |
The free-living bioluminescent marine bacterium, Vibrio harveyi, uses another signaling molecule in addition to an acylated homoserine lactone. This molecule, termed Autoinducer-2 (or AI-2), is a furanosyl borate diester. AI-2, which is also produced and used by a number of Gram-negative and Gram-positive bacteria, is believed to be an evolutionary link between the two major types of quorum sensing circuits. | 1 | Applied and Interdisciplinary Chemistry |
PHLPP is a member of the PPM family of phosphatases, which requires magnesium or manganese for their activity and are insensitive to most common phosphatase inhibitors, including [okadaic acid]. PHLPP1 and PHLPP2 have a similar domain structure, which includes a putative Ras association domain, a pleckstrin homology domain, a series of leucine-rich repeats, a PP2C phosphatase domain, and a C-terminal PDZ ligand. PHLPP1 has two splice variants, PHLPP1α and PHLPP1β, of which PHLPP1β is larger by approximately 1.5 kilobase pairs. PHLPP1α, which was the first PHLPP isoform to be characterized, lacks the N-terminal portion of the protein, including the Ras association domain. PHLPP's domain structure influences its ability to dephosphorylate its substrates. A PHLPP construct lacking the PH domain is unable to decrease PKC phosphorylation, while PHLPP lacking the PDZ ligand is unable to decrease Akt phosphorylation. | 1 | Applied and Interdisciplinary Chemistry |
Gradient echo is a magnetic resonance imaging (MRI) sequence that has wide variety of applications, from magnetic resonance angiography to perfusion MRI and diffusion MRI. Rapid imaging acquisition allows it to be applied to 2D and 3D MRI imaging. Gradient echo uses magnetic gradients to generate a signal, instead of using 180 degrees radiofrequency pulse like spin echo; thus leading to faster image acquisition time. | 0 | Theoretical and Fundamental Chemistry |
The fields that make up the WOA dataset consist of objectively-analysed global grids at 1° spatial resolution. The fields are three-dimensional, and data are typically interpolated onto 33 standardised vertical intervals from the surface (0 m) to the abyssal seafloor (5500 m). In terms of temporal resolution, averaged fields are produced for annual, seasonal and monthly time-scales. The WOA fields include ocean temperature, salinity, dissolved oxygen, apparent oxygen utilisation (AOU), percent oxygen saturation, phosphate, silicic acid, and nitrate. Early editions of the WOA additionally included fields such as mixed layer depth and sea surface height.
In addition to the averaged fields of ocean properties, the WOA also contains fields of statistical information concerning the constituent data that the averages were produced from. These include fields such as the number of data points the average is derived from, their standard deviation and standard error. A lower horizontal resolution (5°) version of the WOA is also available. The WOA dataset is primarily available as compressed ASCII, but since WOA 2005 a netCDF version has also been produced. | 0 | Theoretical and Fundamental Chemistry |
Primer dimers may be visible after gel electrophoresis of the PCR product. PDs in ethidium bromide-stained gels are typically seen as a 30-50 base-pair (bp) band or smear of moderate to high intensity and distinguishable from the band of the target sequence, which is typically longer than 50 bp.
In quantitative PCR, PDs may be detected by melting curve analysis with intercalating dyes, such as SYBR Green I, a nonspecific dye for detection of double-stranded DNA. Because they usually consist of short sequences, the PDs denature at lower temperature than the target sequence and hence can be distinguished by their melting-curve characteristics. | 1 | Applied and Interdisciplinary Chemistry |
The artificial vacuum was first produced in 1643 by Italian scientist Evangelista Torricelli and further developed by German scientist Otto von Guericke with his Magdeburg hemispheres. Guerikes demonstration was documented by Gaspar Schott, in a book that was read by Robert Boyle. Boyle and his assistant Robert Hooke improved Guerickes air pump design and built their own. From this, through various experiments, they formulated what is called Boyles law, which states that the volume of a body of an ideal gas is inversely proportional to its pressure. Soon Jacques Charles formulated Charles Law, which states that the volume of a gas at a constant pressure is proportional to its temperature. Boyles and Charles Laws were combined into the ideal gas law.
Based on these concepts in 1679 Boyles associate, Denis Papin, built a bone digester, which is a closed vessel with a tightly fitting lid that confines steam until a high pressure is generated. Later designs implemented a steam release valve to keep the machine from exploding. By watching the valve rhythmically moving up and down, Papin conceived the idea of a piston and cylinder engine. He did not, however, follow through with his design. In 1697, independent of Papins designs, engineer Thomas Savery built the worlds first steam engine. By 1712 an improved design based on Papins ideas was developed by Thomas Newcomen.
Boyle speaks of Papin as having gone to England in the hope of finding a place in which he could satisfactorily pursue his favorite studies. Boyle himself had already been long engaged in the study of pneumatics, and had been especially interested in the investigations which had been original with Guericke. He admitted young Papin into his laboratory, and the two philosophers worked together at these attractive problems.
He probably invented his "Digester" while in England, and it was first described in a brochure written in English, under the title, "The New Digester." It was subsequently published in Paris.
This was a vessel with a safety valve, which can be tightly closed by a screw and a lid. Food can be cooked along with water in the vessel when the vessel is heated, and the vessel's internal temperature can be raised by as much as the pressure inside the vessel will permit safely. The maximum pressure is limited by a weight placed on the safety valve lever. If the pressure exceeds this limit, the safety valve will be forced open and steam will escape until the pressure drops sufficient for the weight to close the valve again.
It is probable that this essential attachment to the steam boiler had previously been used for other purposes; but Papin is given the credit of having first made use of it to control the pressure of steam. In 1787, Antoine Lavoisier, in his Elements of Chemistry, refers to "Papin's digester" as an example of an environment where high pressure prevents evaporation when he explains that the pressure caused by evaporation of fluid prevents further evaporation. | 0 | Theoretical and Fundamental Chemistry |
Peptoid nanosheets have a very high surface area, which can be readily functionalized to serve as a platform for sensing and templating. Also, their hydrophobic interiors can accommodate hydrophobic small molecule cargos, which have been demonstrated by the sequestration of Nile red when this dye was injected into an aqueous solution of the peptoid nanosheets. For these reasons, the hydrophobic interior of the 2D nanosheets could be an attractive platform for loading or embedding hydrophobic cargo, such as drug molecules, fluorophores, aromatic compounds, and metal nanoparticles. | 0 | Theoretical and Fundamental Chemistry |
*Pleiner, R. (2000) Iron in Archaeology. The European Bloomery Smelters, Praha, Archeologický Ústav Av Cr.
*Veldhuijzen, H.A. (2005) Technical Ceramics in Early Iron Smelting. The Role of Ceramics in the Early First Millennium Bc Iron Production at Tell Hammeh (Az-Zarqa), Jordan. In: Prudêncio, I.Dias, I. and Waerenborgh, J.C. (Eds.) Understanding People through Their Pottery; Proceedings of the 7th European Meeting on Ancient Ceramics (Emac 03)'. Lisboa, Instituto Português de Arqueologia (IPA).
*Veldhuijzen, H.A. and Rehren, Th. (2006) Iron Smelting Slag Formation at Tell Hammeh (Az-Zarqa), Jordan. In: Pérez-Arantegui, J. (Ed.) Proceedings of the 34th International Symposium on Archaeometry, Zaragoza, 3–7 May 2004. Zaragoza, Institución «Fernando el Católico» (C.S.I.C.) Excma. Diputación de Zaragoza. | 1 | Applied and Interdisciplinary Chemistry |
The son of the radical Protestant theologian Gustav Wislicenus, Johannes was born on 24 June 1835 in Kleineichstedt (now part of Querfurt, Saxony-Anhalt) in Prussian Saxony, and entered University of Halle-Wittenberg in 1853. In October 1853 he immigrated to the United States with his family. For a brief time he acted as assistant to Harvard chemist Eben Horsford, and in 1855 was appointed lecturer at the Mechanics' Institute in New York. Returning to Europe in 1856, he continued to study chemistry with Wilhelm Heinrich Heintz at the University of Halle. In 1860, he began lecturing at the University of Zürich, and at the Swiss Polytechnical Institute and by 1868 he was Professor of Chemistry at the university. In 1870, he was chosen to succeed Georg Staedeler as Professor of General Chemistry at the Swiss Polytechnical Institute in Zürich, retaining also the position of full professor at the University of Zürich. In 1872, he succeeded Adolph Strecker in the chair of chemistry at University of Würzburg, and in 1885, he succeeded Hermann Kolbe as Professor of Chemistry at the University of Leipzig, where he died on 6 December 1902. | 0 | Theoretical and Fundamental Chemistry |
Fast fission is fission that occurs when a heavy atom absorbs a high-energy neutron, called a fast neutron, and splits. Most fissionable materials need thermal neutrons, which move more slowly. | 0 | Theoretical and Fundamental Chemistry |
Since the Earth bulges at the equator and mountains and deep oceanic trenches allow for deviations of several kilometers relative to a uniformly smooth spheroid, cosmic rays bombard the Earth's surface unevenly based on the latitude and altitude. Thus, many geographic and geologic considerations must be understood in order for cosmic-ray flux to be accurately determined. Atmospheric pressure, for example, which varies with altitude, can change the production rate of nuclides within minerals by a factor of 30 between sea level and the top of a 5 km high mountain. Even variations in the slope of the ground can affect how far high-energy muons can penetrate the subsurface. Geomagnetic field strength which varies over time affects the production rate of cosmogenic nuclides though some models assume variations of the field strength are averaged out over geologic time and are not always considered. | 0 | Theoretical and Fundamental Chemistry |
Turning now to quantum mechanics an atom or a molecule can be thought of as a collection of point charges (electrons and nuclei), so that the second definition of the dipole applies. The interaction of atom or molecule with a uniform external field is described by the operator
This operator is used as a perturbation in first- and second-order perturbation theory to account for the first- and second-order Stark effect. | 0 | Theoretical and Fundamental Chemistry |
The first accumulators for William Armstrongs hydraulic dock machinery were simple raised water towers. Water was pumped to a tank at the top of these towers by steam pumps. When dock machinery required hydraulic power, the hydrostatic head of the waters height above ground provided the necessary pressure.
These simple accumulators were extremely tall. For instance, Grimsby Dock Tower, built in 1852, is tall. Because of their size, they were costly, and so were constructed for less than a decade. Around the same time, John Fowler was working on the construction of the ferry quay at nearby New Holland but could not use similar hydraulic power as the poor ground conditions did not permit a tall accumulator tower to be built. By the time Grimsby was opened, it was already obsolete as Armstrong had developed the more complex, but much smaller, weighted accumulator for use at New Holland. In 1892 the original Grimsby towers function was replaced, on Fowlers advice, by a smaller weighted accumulator on an adjacent dock, although the tower remains to this day as a well-known landmark.
Other surviving towers include one adjacent to East Float in Birkenhead, England, and another located at the Bramley-Moore Dock, Liverpool, England. The latter tower is to be renovated as part of plans for the proposed development of the area associated with the construction of a new football stadium for Everton F.C. | 1 | Applied and Interdisciplinary Chemistry |
The process of creating fish emulsion begins with whole fish, or with carcass products of fish, such as bones, scales, and skin, which are left after a fish has been processed. The fish and carcass products are then ground into a slurry. After the oils and fish meal are removed from the slurry, the slurry is officially a fish emulsion. Most emulsions are then strained to remove any remaining solids, and sulfuric acid is often added to increase the acidity and prevent the growth of microbes. | 0 | Theoretical and Fundamental Chemistry |
Endogenous sources of specific DNA damage include pathways like hydrolysis, oxidation, alkylation, mismatch of DNA bases, depurination, depyrimidination, double-strand breaks (DSS), and cytosine deamination. DNA lesions can also naturally occur from the release of specific compounds such as reactive oxygen species (ROS), reactive nitrogen species (RNS), reactive carbonyl species (RCS), lipid peroxidation products, adducts, and alkylating agents through metabolic processes. ROS is one of the major endogenous sources of DNA damage and the most studied oxidative DNA adduct is 8-oxo-dG. Other adducts known to form are etheno-, propano-, and malondialdehyde-derived DNA adducts. The aldehydes formed from lipid peroxidation also pose another threat to DNA. Proteins such as "damage-up" proteins (DDPs) can promote endogenous DNA lesions by either increasing the amount of reactive oxygen by transmembrane transporters, losing chromosomes by replisome binding, and stalling replication by transcription factors. For RNA lesions specifically, the most abundant types of endogenous damage include oxidation, alkylation, and chlorination. Phagocytic cells produce radical species that include hypochlorous acid (HOCl), nitric oxide (NO•), and peroxynitrite (ONOO−) to fight infections, and many cell types use nitric oxide as a signaling molecule. However, these radical species can also cause the pathways that form RNA lesions. | 1 | Applied and Interdisciplinary Chemistry |
Prismane or H. It is an isomer of benzene, specifically a valence isomer. Prismane is far less stable than benzene. The carbon (and hydrogen) atoms of the prismane molecule are arranged in the shape of a six-atom triangular prism—this compound is the parent and simplest member of the prismanes class of molecules. Albert Ladenburg proposed this structure for the compound now known as benzene. The compound was not synthesized until 1973. | 0 | Theoretical and Fundamental Chemistry |
G protein - G protein-coupled receptor - G3P - GABA - GABA receptor - GABA-A receptor - gag-onc fusion protein - galanin - gamete - gamma-chain immunoglobulin - gamma-delta T-cell antigen receptor - gastrin - gastrointestinal hormone receptor - gastrula - gel electrophoresis - gene - gene expression - gene pool - gene regulatory network - genetic carrier - genetic code - genetic drift - genetic engineering - genetic fingerprint - genetic recombination - genetics - genome - genomics - genotype - glial fibrillary acidic protein - globin - glucagon - glucagon receptor - glucocorticoid receptor - glucose - glutamate - glutamate receptor - glutamic acid - glutamine - glycerine - glycine - glycine receptor - glycolipid - glycolysis - glycoprotein - gonadorelin - gradient - granulocyte colony-stimulating factor - granulocyte colony-stimulating factor receptor - granulocyte-macrophage colony-stimulating factor - granulocyte-macrophage colony-stimulating factor receptor - granzyme - growth factor receptor - GTP-binding protein - GTPase | 1 | Applied and Interdisciplinary Chemistry |
In some cases, laboratory mix-ups (misidentified gametes, transfer of wrong embryos) have occurred, leading to legal action against the IVF provider and complex paternity suits. An example is the case of a woman in California who received the embryo of another couple and was notified of this mistake after the birth of her son. This has led to many authorities and individual clinics implementing procedures to minimise the risk of such mix-ups. The HFEA, for example, requires clinics to use a double witnessing system, the identity of specimens is checked by two people at each point at which specimens are transferred. Alternatively, technological solutions are gaining favour, to reduce the manpower cost of manual double witnessing, and to further reduce risks with uniquely numbered RFID tags which can be identified by readers connected to a computer. The computer tracks specimens throughout the process and alerts the embryologist if non-matching specimens are identified. Although the use of RFID tracking has expanded in the US, it is still not widely adopted. | 1 | Applied and Interdisciplinary Chemistry |
* Order of Polonia Restituta (2018)
* [https://ptchem.pl/pl/honors/distinctions-and-medals-ptchem Medal Jana Zawidzkiego] (1997)
* Golden Cross of Merit (Poland) (1990) | 0 | Theoretical and Fundamental Chemistry |
The 3-dimensional structure of micrococcal nuclease (then called Staphyloccal nuclease) was solved very early in the history of protein crystallography, in 1969, deposited as now-obsolete Protein Data Bank file 1SNS. Higher-resolution, more recent crystal structures are available for the apo form as Protein Data Bank file 1SNO: [http://www.rcsb.org/pdb/explore/explore.do?structureId=1SNO] and for the thymidine-diphosphate-inhibited form as Protein Data Bank file 3H6M: [http://www.rcsb.org/pdb/explore/explore.do?structureId=3H6M] or 1SNC: [http://www.rcsb.org/pdb/explore/explore.do?structureId=1SNC]. As seen in the ribbon diagram above, the nuclease molecule has 3 long alpha helices and a 5-stranded, barrel-shaped beta sheet, in an arrangement known as the OB-fold (for oligonucleotide-binding fold) as classified in the SCOP database. | 1 | Applied and Interdisciplinary Chemistry |
The Chen-Kao reaction (named after Ko Kuei Chen and Chung-Hsi Kao, Madison, Wisconsin 1926) is a chemical method for determining the presence of pseudoephedrine, ephedrine, and similar phenylalkylamines.
The reaction is used in spot tests and is also known as Chen-Kao test (or simply as Chen, Test T in UN Precursor Test Kit).
The test is often used to distinguish ephedrine, pseudoephedrine, norephedrine, cathinone and methcathinone from amphetamine and methamphetamine,
which do not react with Chen’s test reagent. | 0 | Theoretical and Fundamental Chemistry |
Polymerization-induced phase separation can be initiated either through thermally induced polymerization or photopolymerization. The process general occurs through spinodal decomposition, commonly resulting in the formation of co-continuous phases. | 0 | Theoretical and Fundamental Chemistry |
The Damköhler numbers (Da) are dimensionless numbers used in chemical engineering to relate the chemical reaction timescale (reaction rate) to the transport phenomena rate occurring in a system. It is named after German chemist Gerhard Damköhler, who worked in the fields of chemical engineering, thermodynamics, and fluid dynamics.
The Karlovitz number (Ka) is related to the Damköhler number by Da = 1/Ka.
In its most commonly used form, the first Damköhler number (Da) relates the characteristic residence time scale of particles in a fluid region to the reaction timescale. The residence time scale can take the form of a convection time scale, such as volumetric flow rate through the reactor for continuous (plug flow or stirred tank) or semibatch chemical processes:
In reacting systems that include interphase mass transport, the first Damköhler number can be written as the ratio of the chemical reaction rate to the mass transfer rate
It is also defined as the ratio of the characteristic fluidic and chemical time scales:
Since the reaction rate determines the reaction timescale, the exact formula for the Damköhler number varies according to the rate law equation. For a general chemical reaction A → B following the Power law kinetics of n-th order, the Damköhler number for a convective flow system is defined as:
where:
* k = kinetics reaction rate constant
* C = initial concentration
* n = reaction order
* = mean residence time or space-time
On the other hand, the second Damköhler number (Da) is defined in general as:
It compares the process energy of a thermochemical reaction (such as the energy involved in a nonequilibrium gas process) with a related enthalpy difference (driving force).
In terms of reaction rates:
where
* k is the global mass transport coefficient
* a is the interfacial area
The value of Da provides a quick estimate of the degree of conversion that can be achieved. If Da goes to infinity, the residence time greatly exceeds the reaction time, such that nearly all chemical reactions have taken place during the period of residency. Otherwise if Da goes to 0, the residence time is much shorter than the reaction time, so that no chemical reaction has taken place during the brief period when the fluid particles occupy the reaction location. Similarly, Da goes to 0 implies that the energy of the chemical reaction is negligible compared to the energy of the flow. The limit of the Damköhler number going to infinity is called the Burke–Schumann limit.
As a rule of thumb, when Da is less than 0.1 a conversion of less than 10% is achieved, and when Da is greater than 10 a conversion of more than 90% is expected. | 1 | Applied and Interdisciplinary Chemistry |
Excretion is a process in which metabolic waste
is eliminated from an organism. In vertebrates, this is primarily carried out by the lungs, kidneys, and skin. This is in contrast with secretion, where the substance may have specific tasks after leaving the cell. Excretion is an essential process in all forms of life. For example, in placental mammals, urine is expelled through the urethra, which is part of the excretory system. In unicellular organisms, waste products are discharged directly through the surface of the cell.
During life activities such as cellular respiration, several chemical reactions take place in the body. These are known as metabolism. These chemical reactions produce waste products such as carbon dioxide, water, salts, urea and uric acid. Accumulation of these wastes beyond a level inside the body is harmful to the body. The excretory organs remove these wastes. This process of removal of metabolic waste from the body is known as excretion.
Green plants excrete carbon dioxide and water as respiratory products. In green plants, the carbon dioxide released during respiration gets used during photosynthesis. Oxygen is a by product generated during photosynthesis, and exits through stomata, root cell walls, and other routes. Plants can get rid of excess water by transpiration and guttation. It has been shown that the leaf acts as an excretophore and, in addition to being a primary organ of photosynthesis, is also used as a method of excreting toxic wastes via diffusion. Other waste materials that are exuded by some plants — resin, saps, latex, etc. are forced from the interior of the plant by hydrostatic pressures inside the plant and by absorptive forces of plant cells. These latter processes do not need added energy, they act passively. However, during the pre-abscission phase, the metabolic levels of a leaf are high. Plants also excrete some waste substances into the soil around them.
In animals, the main excretory products are carbon dioxide, ammonia (in ammoniotelics), urea (in ureotelics), uric acid (in uricotelics), guanine (in Arachnida), and creatine. The liver and kidneys clear many substances from the blood (for example, in renal excretion), and the cleared substances are then excreted from the body in the urine and feces.
Aquatic animals usually excrete ammonia directly into the external environment, as this compound has high solubility and there is ample water available for dilution. In terrestrial animals, ammonia-like compounds are converted into other nitrogenous materials, i.e. urea, that are less harmful as there is less water in the environment and ammonia itself is toxic. This process is called detoxification.
Birds excrete their nitrogenous wastes as uric acid in the form of a paste. Although this process is metabolically more expensive, it allows more efficient water retention and it can be stored more easily in the egg. Many avian species, especially seabirds, can also excrete salt via specialized nasal salt glands, the saline solution leaving through nostrils in the beak.
In insects, a system involving Malpighian tubules is used to excrete metabolic waste. Metabolic waste diffuses or is actively transported into the tubule, which transports the wastes to the intestines. The metabolic waste is then released from the body along with fecal matter.
The excreted material may be called ejecta. In pathology the word ejecta is more commonly used. | 1 | Applied and Interdisciplinary Chemistry |
An object's deflective efficiency can never equal or surpass 100%, for example:
*a mirror will never reflect exactly the same amount of light cast upon it, though it may concentrate the light which is reflected into a narrower beam.
*on hitting the ground, a ball previously in free-fall (meaning no force other than gravity acted upon it) will never bounce back up to the place where it first started to descend.
This transfer of some energy into heat or other radiation is a consequence of the theory of thermodynamics, where, for every such interaction, some energy must be converted into alternative forms of energy or is absorbed by the deformation of the objects involved in the collision. | 0 | Theoretical and Fundamental Chemistry |
The conduction through a spherical shell with internal radius, , and external radius, , can be calculated in a similar manner as for a cylindrical shell.
The surface area of the sphere is:
Solving in a similar manner as for a cylindrical shell (see above) produces: | 1 | Applied and Interdisciplinary Chemistry |
There has been call to move away from race and ethnicity in medicine and instead use genetic ancestry as a way to categorize patients. Some alleles that vary in frequency between specific populations have been shown to be associated with differential responses to specific drugs. As a result, some disease-specific guidelines only recommend pharmacogenetic testing for populations where high-risk alleles are more common and, similarly, certain insurance companies will only pay for pharmacogenetic testing for beneficiaries of high-risk populations. | 1 | Applied and Interdisciplinary Chemistry |
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