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Natural-synthetic hybrid polymers are based on the synergic effect between synthetic and biopolymeric constituents. Gelatin-methacryloyl (GelMA) has become a popular biomaterial in the field of bioprinting. GelMA has shown it has viable potential as a bioink material due to its suitable biocompatibility and readily tunable psychochemical properties. Hyaluronic acid (HA)-PEG is another natural-synthetic hybrid polymer that has proven to be very successful in bioprinting applications. HA combined with synthetic polymers aid in obtaining more stable structures with high cell viability and limited loss in mechanical properties after printing. A recent application of HA-PEG in bioprinting is the creation of artificial liver. Lastly, a series of biodegradable polyurethane (PU)-gelatin hybrid polymers with tunable mechanical properties and efficient degradation rates have been implemented in organ printing. This hybrid has the ability to print complicated structures such as a nose-shaped construct.
All of the polymers described above have the potential to be manufactured into implantable, bioartificial organs for purposes including, but not limited to, customized organ restoration, drug screening, as well as metabolic model analysis. | 1 | Applied and Interdisciplinary Chemistry |
In 1883, scientist Osborne Reynolds conducted a fluid dynamics experiment involving water and dye, where he adjusted the velocities of the fluids and observed the transition from laminar to turbulent flow, characterized by the formation of eddies and vortices. Turbulent flow is defined as the flow in which the system's inertial forces are dominant over the viscous forces. This phenomenon is described by Reynolds number, a unit-less number used to determine when turbulent flow will occur. Conceptually, the Reynolds number is the ratio between inertial forces and viscous forces.
The general form for the Reynolds number flowing through a tube of radius (or diameter ):
where is the velocity of the fluid, is its density, is the radius of the tube, and is the dynamic viscosity of the fluid. A turbulent flow in a fluid is defined by the critical Reynolds number, for a closed pipe this works out to approximately
In terms of the critical Reynolds number, the critical velocity is represented as | 1 | Applied and Interdisciplinary Chemistry |
This consists of a refrigeration cycle, where heat is removed from a low-temperature space or source and rejected to a high-temperature sink with the help of external work, and its inverse, the thermodynamic power cycle. In the power cycle, heat is supplied from a high-temperature source to the engine, part of the heat being used to produce work and the rest being rejected to a low-temperature sink. This satisfies the second law of thermodynamics.
A refrigeration cycle describes the changes that take place in the refrigerant as it alternately absorbs and rejects heat as it circulates through a refrigerator. It is also applied to heating, ventilation, and air conditioning HVACR work, when describing the "process" of refrigerant flow through an HVACR unit, whether it is a packaged or split system.
Heat naturally flows from hot to cold. Work is applied to cool a living space or storage volume by pumping heat from a lower temperature heat source into a higher temperature heat sink. Insulation is used to reduce the work and energy needed to achieve and maintain a lower temperature in the cooled space. The operating principle of the refrigeration cycle was described mathematically by Sadi Carnot in 1824 as a heat engine.
The most common types of refrigeration systems use the reverse-Rankine vapor-compression refrigeration cycle, although absorption heat pumps are used in a minority of applications.
Cyclic refrigeration can be classified as:
#Vapor cycle, and
#Gas cycle
Vapor cycle refrigeration can further be classified as:
#Vapor-compression refrigeration
#Sorption Refrigeration
##Vapor-absorption refrigeration
##Adsorption refrigeration | 0 | Theoretical and Fundamental Chemistry |
A. Hari Reddi (born October 20, 1942) is a Distinguished Professor and holder of the Lawrence J. Ellison Endowed Chair in Musculoskeletal Molecular Biology at the University of California, Davis. He was previously the Virginia M. and William A. Percy Chair and Professor in Orthopaedic Surgery, Professor of Biological Chemistry, and Professor of Oncology at the Johns Hopkins University School of Medicine. Professor Reddi's research played an indispensable role in the identification, isolation and purification of bone morphogenetic proteins (BMPs) that are involved in bone formation and repair. The molecular mechanism of bone induction studied by Professor Reddi led to the conceptual advance in tissue engineering that morphogens in the form of metabologens bound to an insoluble extracellular matrix scaffolding act in collaboration to stimulate stem cells to form cartilage and bone. The Reddi laboratory has also made important discoveries unraveling the role of the extracellular matrix in bone and cartilage tissue regeneration and repair. | 1 | Applied and Interdisciplinary Chemistry |
Hydrogen bromide (along with hydrobromic acid) is produced by combining hydrogen and bromine at temperatures between 200 and 400 °C. The reaction is typically catalyzed by platinum or asbestos. | 0 | Theoretical and Fundamental Chemistry |
The proposed pathway for electron transport prior to ubiquinone reduction is as follows: NADH – FMN – N3 – N1b – N4 – N5 – N6a – N6b – N2 – Q, where Nx is a labelling convention for iron sulfur clusters. The high reduction potential of the N2 cluster and the relative proximity of the other clusters in the chain enable efficient electron transfer over long distance in the protein (with transfer rates from NADH to N2 iron-sulfur cluster of about 100 μs).
The equilibrium dynamics of Complex I are primarily driven by the quinone redox cycle. In conditions of high proton motive force (and accordingly, a ubiquinol-concentrated pool), the enzyme runs in the reverse direction. Ubiquinol is oxidized to ubiquinone, and the resulting released protons reduce the proton motive force. | 1 | Applied and Interdisciplinary Chemistry |
In magnets, there also exist different types of solitons and other nonlinear waves. These magnetic solitons are an exact solution of classical nonlinear differential equations — magnetic equations, e.g. the Landau–Lifshitz equation, continuum Heisenberg model, Ishimori equation, nonlinear Schrödinger equation and others. | 1 | Applied and Interdisciplinary Chemistry |
John Macadam was born at Northbank, Glasgow, Scotland, on 29 May 1827, the son of William Macadam (1783-1853) and Helen, née Stevenson (1803-1857). His father was a Glasgow businessman, who owned a spinning and textile printing works in Kilmarnock, and was a burgess and a bailie (magistrate) of Glasgow. His fellow industrialists and he in the craft had developed, using chemistry, the processes for the large-scale industrial printing of fabrics for which these plants in the area became known.
John Macadam was privately educated in Glasgow; he studied chemistry at the Andersonian University (now the University of Strathclyde) and went for advanced study at the University of Edinburgh under Professor William Gregory. In 1846–47, he went on to serve as assistant to Professor George Wilson at the University of Edinburgh in his laboratory in Brown Square. He was elected a fellow of the Royal Scottish Society of Arts that year, and in 1848, a member of the Glasgow Philosophical Society. He then studied medicine at the University of Glasgow (LFPS, MD,1854; FFPSG,1855).
He was a member of what became a small dynasty of Scottish scientists and lecturers in analytical chemistry, which included, other than himself, his eldest half brother William Macadam, his immediate younger brother Stevenson Macadam (a younger brother Charles Thomas Macadam, although not involved as a scientist, was also indirectly involved in chemistry becoming a senior partner in a chemical fertiliser company) and nephews William Ivison Macadam and Stevenson J. C. G. Macadam, as well as the former nephew's daughter, his great niece Elison A. Macadam.
On 8 June 1855, aged 28, Macadam sailed for Melbourne in the Colony of Victoria, Australia, on the sailing ship Admiral. He arrived on 8 September 1855. | 0 | Theoretical and Fundamental Chemistry |
At proposed therapeutic concentrations, this molecule lacks anti-inflammatory activity, and does not inhibit either cyclooxygenase 1 (COX-1) or cyclooxygenase 2 (COX-2) enzymes. Only the S-enantiomers of arylpropionic acid NSAID can potently inhibit COX, whereas the R-enantiomers exert almost no COX activity. R-Flurbiprofen is inefficiently converted into S-flurbiprofen, with 1.5% of the R-enantiomer undergoing bioinversion to the S-form. Although this compound lacks activity against COX, studies have shown that this drug is a potent reducer of levels of beta amyloid, the main constituent of amyloid plaques in Alzheimer's disease, and therefore there was interest in this drug as a therapeutic agent. | 0 | Theoretical and Fundamental Chemistry |
The trifluoromethyl group is a functional group that has the formula -CF. The naming of is group is derived from the methyl group (which has the formula -CH), by replacing each hydrogen atom by a fluorine atom. Some common examples are trifluoromethane H–, 1,1,1-trifluoroethane –, and hexafluoroacetone –CO–. Compounds with this group are a subclass of the organofluorines. | 0 | Theoretical and Fundamental Chemistry |
Due to the increase in safety concerns and operating costs of common analytic methods (ICP-MS, ICP-AAS, and ICP-OES), the Photonics Lab on a Chip (PhLOC) is becoming an increasingly popular tool for the analysis of actinides and nitrates in spent nuclear waste. The PhLOC is based on the simultaneous application of Raman and UV-Vis-NIR spectroscopy, which allows for the analysis of more complex mixtures which contain several actinides at different oxidation states. Measurements made with these methods have been validated at the bulk level for industrial tests, and are observed to have a much lower variance at the micro-scale. This approach has been found to have molar extinction coefficients (UV-Vis) in line with known literature values over a comparatively large concentration span for 150 μL via elongation of the measurement channel, and obeys Beer's Law at the micro-scale for U(IV). Through the development of a spectrophotometric approach to analyzing spent fuel, an on-line method for measurement of reactant quantities is created, increasing the rate at which samples can be analyzed and thus decreasing the size of deviations detectable within reprocessing.
Through the application of the PhLOC, flexibility and safety of operational methods are increased. Since the analysis of spent nuclear fuel involves extremely harsh conditions, the application of disposable and rapidly produced devices (Based on castable and/or engravable materials such as PDMS, PMMA, and glass) is advantageous, although material integrity must be considered under specific harsh conditions. Through the usage of fiber optic coupling, the device can be isolated from instrumentation, preventing irradiative damage and minimizing the exposure of lab personnel to potentially harmful radiation, something not possible on the lab scale nor with the previous standard of analysis. The shrinkage of the device also allows for lower amounts of analyte to be used, decreasing the amount of waste generated and exposure to hazardous materials.
Expansion of the PhLOC to miniaturize research of the full nuclear fuel cycle is currently being evaluated, with steps of the PUREX process successfully being demonstrated at the micro-scale. Likewise, the microfluidic technology developed for the analysis of spent nuclear fuel is predicted to expand horizontally to analysis of other actinide, lanthanides, and transition metals with little to no modification. | 1 | Applied and Interdisciplinary Chemistry |
The catalytic chain transfer process was commercialized very soon after its discovery. The initial commercial outlet was the production of chemically reactive macromonomers to be incorporated into paints for the automotive industry. Federally mandated VOC restrictions are leading to the elimination of solvents from the automotive finishes and the lower molecular weight chain transfer products are often fluids. Incorporation of monomers such as glycidyl methacrylate or hydroxyethylmethacrylate (HEMA) into the macromonomers aid curing processes. Macromonomers incorporating HEMA can be effective in the dispersion of pigments in the paints. The chemistry is very effective under emulsion polymerisation conditions and has been used in the printing industry since 2000. The vinylic end group acts as an addition fragmentation agent and has been utilised to make multi block copolymers and derivatives used as stress relief agents in dental restoration by 3M. | 0 | Theoretical and Fundamental Chemistry |
Soils act as a major sink for atmospheric methane through the methanotrophic bacteria that reside within them. This occurs with two different types of bacteria. "High capacity-low affinity" methanotrophic bacteria grow in areas of high methane concentration, such as waterlogged soils in wetlands and other moist environments. And in areas of low methane concentration, "low capacity-high affinity" methanotrophic bacteria make use of the methane in the atmosphere to grow, rather than relying on methane in their immediate environment. Methane oxidation allows methanotrophic bacteria to use methane as a source of energy, reacting methane with oxygen and as a result producing carbon dioxide and water.
: CH + 2O → CO + 2HO
Forest soils act as good sinks for atmospheric methane because soils are optimally moist for methanotroph activity, and the movement of gases between soil and atmosphere (soil diffusivity) is high. With a lower water table, any methane in the soil has to make it past the methanotrophic bacteria before it can reach the atmosphere. Wetland soils, however, are often sources of atmospheric methane rather than sinks because the water table is much higher, and the methane can be diffused fairly easily into the air without having to compete with the soil's methanotrophs.
Methanotrophic bacteria also occur in the underwater sediments. Their presence can often efficiently limit emissions from sources such as the underwater permafrost in areas like the Laptev Sea. | 1 | Applied and Interdisciplinary Chemistry |
In 2007 and 2008, a man (Timothy Ray Brown) was cured of HIV by repeated hematopoietic stem cell transplantation (see also allogeneic stem cell transplantation, allogeneic bone marrow transplantation, allotransplantation) with double-delta-32 mutation which disables the CCR5 receptor. This cure was accepted by the medical community in 2011. It required complete ablation of existing bone marrow, which is very debilitating.
In August two of three subjects of a pilot study were confirmed to have been cured from chronic lymphocytic leukemia (CLL). The therapy used genetically modified T cells to attack cells that expressed the CD19 protein to fight the disease. In 2013, the researchers announced that 26 of 59 patients had achieved complete remission and the original patient had remained tumor-free.
Human HGF plasmid DNA therapy of cardiomyocytes is being examined as a potential treatment for coronary artery disease as well as treatment for the damage that occurs to the heart after myocardial infarction.
In 2011, Neovasculgen was registered in Russia as the first-in-class gene-therapy drug for treatment of peripheral artery disease, including critical limb ischemia; it delivers the gene encoding for VEGF. Neovasculogen is a plasmid encoding the CMV promoter and the 165 amino acid form of VEGF. | 1 | Applied and Interdisciplinary Chemistry |
The recommendations include a description of hydrogen names for acids. The following examples illustrate the method:
Note that the difference from the compositional naming method (hydrogen sulfide) as in hydrogen naming there is NO space between the electropositive and electronegative components.
This method gives no structural information regarding the position of the hydrons (hydrogen atoms). If this information is to be conveyed then the additive name should be used (see the list below for examples). | 0 | Theoretical and Fundamental Chemistry |
Conductometry is a measurement of electrolytic conductivity to monitor a progress of chemical reaction. Conductometry has notable application in analytical chemistry, where conductometric titration is a standard technique. In usual analytical chemistry practice, the term conductometry is used as a synonym of conductometric titration while the term conductimetry is used to describe non-titrative applications. Conductometry is often applied to determine the total conductance of a solution or to analyze the end point of titrations that include ions. | 0 | Theoretical and Fundamental Chemistry |
Gerhard Herzberg was the first to find spectroscopic lines of neutral H when he was 75 years old in 1979. Later he announced that this observation was one of his favourite discoveries. The lines came about from a cathode discharge tube. The reason that earlier observers could not see any H spectral lines, was due to them being swamped by the spectrum of the much more abundant H. The important advance was to separate out H so it could be observed alone. Separation uses mass spectroscopy separation of the positive ions, so that H with mass 3 can be separated from H with mass 2. However there is still some contamination from HD, which also has mass 3.
The spectrum of H is mainly due to transitions to the longer lived state of 2pA". The spectrum can be measured via a two step photo-ionization method.
Transitions dropping to the lower 2sA' state are affected by its very short lifetime in what is called predissociation. The spectral lines involved are broadened. In the spectrum there are bands due to rotation with P Q and R branches. The R branch is very weak in H isotopomer but strong with D (trideuterium).
The symmetric stretch vibration mode has a wave number of 3213.1 cm for the 3sA' level and 3168 cm for 3dE" and 3254 cm for 2pA". The bending vibrational frequencies are also quite similar to those for . | 0 | Theoretical and Fundamental Chemistry |
In organic chemistry, an imine ( or ) is a functional group or organic compound containing a carbon–nitrogen double bond (). The nitrogen atom can be attached to a hydrogen or an organic group (R). The carbon atom has two additional single bonds. Imines are common in synthetic and naturally occurring compounds and they participate in many reactions. | 0 | Theoretical and Fundamental Chemistry |
In reference to biochemistry, this is an important concept as far as kinetics is concerned in metalloproteins. This can allow for the rapid synthesis and degradation of substrates in biological systems. | 1 | Applied and Interdisciplinary Chemistry |
Neutron degeneracy is analogous to electron degeneracy and exists in neutron stars, which are partially supported by the pressure from a degenerate neutron gas. Neutron stars are formed either directly from the supernova of stars with masses between 10 and 25 M (solar masses), or by white dwarfs acquiring a mass in excess of the Chandrasekhar limit of 1.44 M, usually either as a result of a merger or by feeding off of a close binary partner. Above the Chandrasekhar limit, the gravitational pressure at the core exceeds the electron degeneracy pressure, and electrons begin to combine with protons to produce neutrons (via inverse beta decay, also termed electron capture). The result is an extremely compact star composed of "nuclear matter", which is predominantly a degenerate neutron gas with a small admixture of degenerate proton and electron gases.
Neutrons in a degenerate neutron gas are spaced much more closely than electrons in an electron-degenerate gas because the more massive neutron has a much shorter wavelength at a given energy. This phenomenon is compounded by the fact that the pressures within neutron stars are much higher than those in white dwarfs. The pressure increase is caused by the fact that the compactness of a neutron star causes gravitational forces to be much higher than in a less compact body with similar mass. The result is a star with a diameter on the order of a thousandth that of a white dwarf.
The properties of neutron matter set an upper limit to the mass of a neutron star, the Tolman–Oppenheimer–Volkoff limit, which is analogous to the Chandrasekhar limit for white dwarf stars. | 0 | Theoretical and Fundamental Chemistry |
In radical trifluoromethylation the active species is the trifluoromethyl free radical. Reagents such as bromotrifluoromethane and haloform have been used for this purpose but in response to the Montreal Protocol alternatives such as trifluoroiodomethane have been developed as replacement. One particular combination is CFI / triethylborane
Other reagents that generate the CF radical are sodium trifluoromethanesulfinate and bis(trifluoroacetyl) peroxide.
In the CF radical the fluorine atom is an electron-withdrawing group via the inductive effect but also a weak pi donor through interaction of the fluorine lone pair with the radical center's SOMO. Compared to the methyl radical the CF radical is pyramidal (angle 107.8 °C ) with a large inversion barrier, electrophilic and also more reactive. In reaction with styrene it is 440 times more reactive. An early report (1949) describes the photochemical reaction of iodotrifluoromethane with ethylene to 3-iodo-1,1,1-trifluoropropane. Reagents that have been reported for the direct trifluoromethylation of arenes are CFI, CFBr (thermal or photochemical), silver trifluoroacetate/TiO (photochemical) and sodium trifluoromethanesulfinate/Cu(OSOCF)/tBuOOH. | 0 | Theoretical and Fundamental Chemistry |
Viral transport medium (VTM) is a solution used to preserve virus specimens after collection so that they can be transported and analysed in a laboratory at a later time. Unless stored in an ultra low temperature freezer or in liquid nitrogen, virus samples, and especially RNA virus samples, are prone to degradation. However, such cooling equipment is seldom available in the field due to their cumbersome size, weight, and in the case of freezers, high energy consumption. Hence, there is a need for VTM; a chemical preservative that can be used at ambient temperature. Chemical components may include saline solution, phosphate-buffered saline (PBS), or fetal bovine serum (FBS). VTM must be sterile to avoid introducing contamination to the specimen.
In the United States, the FDA and CDC publish guidelines for VTM production. | 1 | Applied and Interdisciplinary Chemistry |
During the M-to-G1 transition, pRb is then progressively dephosphorylated by PP1, returning to its growth-suppressive hypophosphorylated state.
pRb family proteins are components of the DREAM complex composed of DP, E2F4/5, RB-like (p130/p107) And MuvB (Lin9:Lin37:Lin52:RbAbP4:Lin54). The DREAM complex is assembled in Go/G1 and maintains quiescence by assembling at the promoters of > 800 cell-cycle genes and mediating transcriptional repression. Assembly of DREAM requires DYRK1A (Ser/Thr kinase) dependant phosphorylation of the MuvB core component, Lin52 at Serine28. This mechanism is crucial for recruitment of p130/p107 to the MuvB core and thus DREAM assembly. | 1 | Applied and Interdisciplinary Chemistry |
Despite being generally inert, carbon tetrachloride can undergo various reactions. Hydrogen or an acid in the presence of an iron catalyst can reduce carbon tetrachloride to chloroform, dichloromethane, chloromethane and even methane. When its vapours are passed through a red-hot tube, carbon tetrachloride dechlorinates to tetrachloroethylene and hexachloroethane.
Carbon tetrachloride, when treated with HF, gives various compounds such as trichlorofluoromethane (R-11), dichlorodifluoromethane (R-12), chlorotrifluoromethane (R-13) and carbon tetrafluoride with HCl as the by-product:
This was once one of the main uses of carbon tetrachloride, as R-11 and R-12 were widely used as refrigerants.
An alcohol solution of potassium hydroxide decomposes it to potassium chloride and potassium carbonate in water:
When a mixture of carbon tetrachloride and carbon dioxide is heated to 350 degrees C, it gives phosgene: A similar reaction with carbon monoxide instead gives phosgene and tetrachloroethylene:
Reaction with hydrogen sulfide gives thiophosgene:
Reaction with sulfur trioxide gives phosgene and pyrosulfuryl chloride:
Reaction with phosphoric anhydride gives phosgene and phosphoryl chloride:
Carbon tetrachloride reacts with dry zinc oxide at 200 degrees Celsius to yield zinc chloride, phosgene and carbon dioxide: | 1 | Applied and Interdisciplinary Chemistry |
Hydrazones are oxidized (dehydrogenation) for example with silver oxide or mercury oxide for example the synthesis of from acetone hydrazone. Other oxidizing reagents are lead tetraacetate, manganese dioxide and the Swern reagent. Tosyl hydrazones RRC=N-NHTs are reacted with base for example triethylamine in the synthesis of crotyl diazoacetate and in the synthesis of phenyldiazomethane from PhCHNHTs and sodium methoxide.
Reaction of a carbonyl group with the hydrazine 1,2-bis(tert-butyldimethylsilyl)hydrazine to form the hydrazone is followed by reaction with the iodane difluoroiodobenzene yields the diazo compound: | 0 | Theoretical and Fundamental Chemistry |
Mixing simple metal salts with solutions of amino acids near neutral or elevated pH often affords bis- or tris complexes. For metal ions that prefer octahedral coordination, these complexes often adopt the stoichiometry M(aa) (aa = amino carboxylate, such as glycinate, HNCHCO).
Complexes of the 3:1 stoichiometry have the formula is [M(OCC(R)HNH)]. Such complexes adopt octahedral coordination geometry. These complexes can exist in facial and meridional isomers, both of which are chiral. The stereochemical possibilities increase when the amino acid ligands are not homochiral. Both the violet meridional and red-pink facial isomers of tris(glycinato)cobalt(III) have been characterized With L-alanine, L-leucine, and other amino acids, one obtains four stereoisomers. With cysteine, the amino acid binds through N and thiolate.
Complexes with the 2:1 stoichiometry are illustrated by copper(II) glycinate [Cu(OCC(R)HNH)], which exists both in anhydrous and pentacoordinate geometries. When the metal is square planar, these complexes can exist as cis and trans isomers. The stereochemical possibilities increase when the amino acid ligands are not homochiral. Homoleptic complexes are also known where the amino carboxylate is tridentate amino acids. One such complex is Ni(κ-histidinate). | 0 | Theoretical and Fundamental Chemistry |
The Scatchard method is less used nowadays because of the availability of computer programs that directly fit parameters to binding data. Mathematically, the Scatchard equation is related to Eadie-Hofstee method, which is used to infer kinetic properties from enzyme reaction data. Many modern methods for measuring binding such as surface plasmon resonance and isothermal titration calorimetry provide additional binding parameters that are globally fit by computer-based iterative methods. | 1 | Applied and Interdisciplinary Chemistry |
Made of high gem quality, flawless diamonds, usually with 16 facets, they typically weigh to carat (25 to 70 mg). The culet (tip) is ground and polished to a hexadecagonal surface parallel to the table. The culets of the two diamonds face one another, and must be perfectly parallel in order to produce uniform pressure and to prevent dangerous strains. Specially selected anvils are required for specific measurements – for example, low diamond absorption and luminescence is required in corresponding experiments. | 0 | Theoretical and Fundamental Chemistry |
Martha Austin Phelps was an American chemist who conducted research in measuring metal concentrations and developed several analytical protocols to do so. She also worked on the early development of ester synthesis. In between conducting research, she worked as school teacher teaching chemistry and physics. She finished her career as an activist in women's academic clubs. Her chemistry career lasted approximately 10 years, resulting in 15 publications, which set her apart as one of the most skilled female chemists within the first generation of women chemists in the United States. | 0 | Theoretical and Fundamental Chemistry |
Magnetic recording relies on the use of hard ferrimagnetic or ferromagnetic materials. These require strong external magnetic fields to be magnetized, and retain substantial residual magnetization after the magnetizing field is removed. Two fundamental magnetic properties, relevant for audio recording, are:
* Saturation remanence limits maximum output level and, indirectly, dynamic range of audio recordings. Remanence of audio tapes, referred to quarter-inch tape width, varies from around for basic ferric tapes to for Type IV tapes; advertised remanence of the 1986 JVC Type IV cassette reached .
* Coercivity is a measure of the external magnetic flux required to magnetize the tape, and an indicator of the necessary bias level. The coercivity of audio tapes varies from to . High-coercivity particles are more difficult to erase, bias and record, but also less prone to high-frequency losses during recording, and to external interference and self-demagnetization during storage.
A useful figure of merit of tape technology is the squareness ratio of the hysteresis curve. It is an indicator of tape uniformity and its linearity in analogue recording. An increase in the squareness ratio defers the onset of compression and distortion, and allows fuller utilization of the tape's dynamic range within the limits of remanence. The squareness ratio of basic ferric tapes rarely exceeds 0.75, and the squareness ratio of the best tapes exceeds 0.9. | 0 | Theoretical and Fundamental Chemistry |
Cryopreservation can be performed as oocyte cryopreservation before fertilisation, or as embryo cryopreservation after fertilisation.
The Rand Consulting Group has estimated there to be 400,000 frozen embryos in the United States in 2006. The advantage is that patients who fail to conceive may become pregnant using such embryos without having to go through a full IVF cycle. Or, if pregnancy occurred, they could return later for another pregnancy. Spare oocytes or embryos resulting from fertility treatments may be used for oocyte donation or embryo donation to another aspiring parent, and embryos may be created, frozen and stored specifically for transfer and donation by using donor eggs and sperm. Also, oocyte cryopreservation can be used for those who are likely to lose their ovarian reserve due to undergoing chemotherapy.
By 2017, many centres have adopted embryo cryopreservation as their primary IVF therapy, and perform few or no fresh embryo transfers. The two main reasons for this have been better endometrial receptivity when embryos are transferred in cycles without exposure to ovarian stimulation and also the ability to store the embryos while awaiting the results of preimplantation genetic testing.
The outcome from using cryopreserved embryos has uniformly been positive with no increase in birth defects or development abnormalities. | 1 | Applied and Interdisciplinary Chemistry |
The Pakistan Engineering Council (Urdu: ; acronym: PEC) is a professional body for accreditation of engineering education and regulation of engineering profession in Pakistan. It was established on 10 January 1976 by the Parliament under the PEC Act, 1976. The council also registers engineers and professional engineers and grants license to consulting and constructing/operating engineering firms working in Pakistan. | 1 | Applied and Interdisciplinary Chemistry |
The amount of water vapor in an atmosphere is constrained by the restrictions of partial pressures and temperature. Dew point temperature and relative humidity act as guidelines for the process of water vapor in the water cycle. Energy input, such as sunlight, can trigger more evaporation on an ocean surface or more sublimation on a chunk of ice on top of a mountain. The balance between condensation and evaporation gives the quantity called vapor partial pressure.
The maximum partial pressure (saturation pressure) of water vapor in air varies with temperature of the air and water vapor mixture. A variety of empirical formulas exist for this quantity; the most used reference formula is the Goff-Gratch equation for the SVP over liquid water below zero degrees Celsius:
where , temperature of the moist air, is given in units of kelvin, and is given in units of millibars (hectopascals).
The formula is valid from about −50 to 102 °C; however there are a very limited number of measurements of the vapor pressure of water over supercooled liquid water. There are a number of other formulae which can be used.
Under certain conditions, such as when the boiling temperature of water is reached, a net evaporation will always occur during standard atmospheric conditions regardless of the percent of relative humidity. This immediate process will dispel massive amounts of water vapor into a cooler atmosphere.
Exhaled air is almost fully at equilibrium with water vapor at the body temperature. In the cold air the exhaled vapor quickly condenses, thus showing up as a fog or mist of water droplets and as condensation or frost on surfaces. Forcibly condensing these water droplets from exhaled breath is the basis of exhaled breath condensate, an evolving medical diagnostic test.
Controlling water vapor in air is a key concern in the heating, ventilating, and air-conditioning (HVAC) industry. Thermal comfort depends on the moist air conditions. Non-human comfort situations are called refrigeration, and also are affected by water vapor. For example, many food stores, like supermarkets, utilize open chiller cabinets, or food cases, which can significantly lower the water vapor pressure (lowering humidity). This practice delivers several benefits as well as problems. | 1 | Applied and Interdisciplinary Chemistry |
Diffusion dialysis is a spontaneous separation process where the driving force which produces the separation is the concentration gradient. It has an increase in entropy and decrease in Gibbs free energy which means that it is thermodynamically favorable. Diffusion dialysis uses anion exchange membranes (AEM) or cation exchange membranes (CEM) depending on the compounds to separate. AEM allows the passage of anions while it obstructs the passage of cations due to the co-ion rejection and preservation of electrical neutrality. The opposite happens with cation exchange membranes. | 1 | Applied and Interdisciplinary Chemistry |
Males produce approximately 150 μmol to 200 μmol of creatinine per kilogram of body weight per 24 h while females produce approximately 100 μmol/kg/24 h to 150 μmol/kg/24 h. In normal circumstances, all this daily creatinine production is excreted in the urine.
Creatinine concentration is checked during standard urine drug tests. An expected creatinine concentration indicates the test sample is undiluted, whereas low amounts of creatinine in the urine indicate either a manipulated test or low initial baseline creatinine concentrations. Test samples considered manipulated due to low creatinine are not tested, and the test is sometimes considered failed. | 1 | Applied and Interdisciplinary Chemistry |
A catalytic triad is a set of three coordinated amino acids that can be found in the active site of some enzymes. Catalytic triads are most commonly found in hydrolase and transferase enzymes (e.g. proteases, amidases, esterases, acylases, lipases and β-lactamases). An acid-base-nucleophile triad is a common motif for generating a nucleophilic residue for covalent catalysis. The residues form a charge-relay network to polarise and activate the nucleophile, which attacks the substrate, forming a covalent intermediate which is then hydrolysed to release the product and regenerate free enzyme. The nucleophile is most commonly a serine or cysteine amino acid, but occasionally threonine or even selenocysteine. The 3D structure of the enzyme brings together the triad residues in a precise orientation, even though they may be far apart in the sequence (primary structure).
As well as divergent evolution of function (and even the triad's nucleophile), catalytic triads show some of the best examples of convergent evolution. Chemical constraints on catalysis have led to the same catalytic solution independently evolving in at least 23 separate superfamilies. Their mechanism of action is consequently one of the best studied in biochemistry. | 1 | Applied and Interdisciplinary Chemistry |
Chirality is another property that a DNAzyme can exploit. DNA occurs in nature as a right-handed double helix and in asymmetric synthesis a chiral catalyst is a valuable tool in the synthesis of chiral molecules from an achiral source. In one application an artificial DNA catalyst was prepared by attaching a copper ion to it through a spacer. The copper - DNA complex catalysed a Diels-Alder reaction in water between cyclopentadiene and an aza chalcone. The reaction products (endo and exo) were found to be present in an enantiomeric excess of 50%. Later it was found that an enantiomeric excess of 99% could be induced, and that both the rate and the enantioselectivity were related to the DNA sequence. | 0 | Theoretical and Fundamental Chemistry |
The synthesis of the D ring (scheme 6) started from 44 with allylic bromination with copper(I) bromide and benzoyl tert-butyl peroxide to bromide 45. By adding even more bromide, another bromide 46 formed (both compounds are in chemical equilibrium) with the bromine atom in an axial position. Osmium tetroxide added two hydroxyl groups to the exocyclic double bond in diol 47 and oxetane ring-closure to 48 took place with DBU in a nucleophilic substitution. Then, acylation of the C4 hydroxyl group (acetic anhydride, DMAP, pyridine) resulted in acetate 49. In the final steps phenyllithium opened the ester group to form hydroxy carbonate 50, both TES groups were removed (HF, pyr) to triol 51 (baccatin III) and the C7 hydroxyl group was back-protected to 52. | 0 | Theoretical and Fundamental Chemistry |
Several applications have been developed that interrogate SNPs by hybridizing complementary DNA probes to the SNP site. The challenge of this approach is reducing cross-hybridization between the allele-specific probes. This challenge is generally overcome by manipulating the hybridization stringency conditions. | 1 | Applied and Interdisciplinary Chemistry |
Ceramic anode materials include Ni-Fe, Sn, and Ni-Li based oxides. These anodes show promise as they are extremely stable during the reduction process at normal operating temperatures (~1000 °C), ensuring that the Al is not contaminated. The stability of these anodes also allows them to be used with a range of electrolytes. However, ceramic anodes suffer from poor electrical conductivity and low mechanical strength.
Alternatively metal anodes boast high mechanical strength and conductivity but tend to corrode easily during the reduction process. Some material systems that are used in inert metal anodes include Al-Cu, Ni-Cu, and Fe-Ni-Cu systems. Additional additives such as Sn, Ag, V, Nb, Ir, Ru can be included in these systems to form non reactive oxides on the anode surface, but this significantly increases the cost and embodied energy of the anode.
Cermet anodes are the combination of a metal and ceramic anode, and aim to take advantage of the desirable properties of both; the electrical cpnductivity and toughness of the metal and stability of the ceramic. These anodes often consist of a combination of the above metal and ceramic materials. In industry, Alcoa and Rio Tinto have formed a joint venture, Elysis, to commercialize inert anode technology developed by Alcoa. The inert anode is a cermet material, a metallic dispersion of copper alloy in a ceramic matrix of nickel ferrite. Unfortunately, as the number of anode components increases , the structure of the anode becomes more unstable. As a result. cermet anodes also suffer from corrosion issues during reduction. | 1 | Applied and Interdisciplinary Chemistry |
was first discovered in 1974 and subsequently appeared on the street as an alternative to the clandestinely produced fentanyl analog α-methylfentanyl. However, it quickly became apparent that was much more potent than α-methylfentanyl, and correspondingly more dangerous.
While was initially sold on the black market for only a short time between 1984 and 1985, its high potency made it an attractive target to clandestine drug producers, as racemic is 10–15 times more potent than fentanyl, and so correspondingly larger amounts of cut product for street sales can be produced for an equivalent amount of effort as for producing fentanyl itself; one gram of might be sufficient to produce several thousand dosage units once diluted for sale. has thus reappeared several times, at various places around the world.
The only country in the world with significant (200+ deaths a year, more than 10,000 addicts) abuse of this chemical is Estonia, where a dose of costs 10 €, and other opiates are not generally available since the end of the 2000s. Approximately 1100 deaths from fentanyl and abuse were recorded in Estonia between 2005–2013, compared to approximately 450 deaths in Sweden, Germany, UK, Finland and Greece combined during the same period.
Other opioid analogs even more potent still than are known, such as carfentanil and ohmefentanyl, but these are significantly more difficult to manufacture than . Since 2016 fentanyl seizures in Estonia contains mostly carfentanil or cyclopropylfentanyl.
has similar effects to fentanyl, but is far more potent due to increased binding affinity to its target site. Since fentanyl itself is already highly potent, is extremely dangerous when used recreationally, and has resulted in many deaths among recreational opioid users ingesting the drug. Side effects of fentanyl analogs are similar to those of fentanyl itself, which include itching, nausea and potentially serious respiratory depression, which can be life-threatening. Fentanyl analogs have killed hundreds of people throughout Europe and the former Soviet republics since the most recent resurgence in use began in Estonia in the early 2000s, and novel derivatives continue to appear. | 1 | Applied and Interdisciplinary Chemistry |
GaAs has been used to produce near-infrared laser diodes since 1962. It is often used in alloys with other semiconductor compounds for these applications.
N-type GaAs doped with silicon donor atoms (on Ga sites) and boron acceptor atoms (on As sites) responds to ionizing radiation by emitting scintillation photons. At cryogenic temperatures it is among the brightest scintillators known and is a promising candidate for detecting rare electronic excitations from interacting dark matter, due to the following six essential factors:
# Silicon donor electrons in GaAs have a binding energy that is among the lowest of all known n-type semiconductors. Free electrons above per cm are not “frozen out" and remain delocalized at cryogenic temperatures.
# Boron and gallium are group III elements, so boron as an impurity primarily occupies the gallium site. However, a sufficient number occupy the arsenic site and act as acceptors that efficiently trap ionization event holes from the valence band.
# After trapping an ionization event hole from the valence band, the boron acceptors can combine radiatively with delocalized donor electrons to produce photons 0.2 eV below the cryogenic band-gap energy (1.52 eV). This is an efficient radiative process that produces scintillation photons that are not absorbed by the GaAs crystal.
# There is no afterglow, because metastable radiative centers are quickly annihilated by the delocalized electrons. This is evidenced by the lack of thermally induced luminescence.
# N-type GaAs has a high refractive index (~3.5) and the narrow-beam absorption coefficient is proportional to the free electron density and typically several per cm. One would expect that almost all of the scintillation photons should be trapped and absorbed in the crystal, but this is not the case. Recent Monte Carlo and Feynman path integral calculations have shown that the high luminosity could be explained if most of the narrow beam absorption is not absolute absorption but a novel type of optical scattering from the conduction electrons with a cross section of about 5 x 10 cm that allows scintillation photons to escape total internal reflection. This cross section is about 10 times larger than Thomson scattering but comparable to the optical cross section of the conduction electrons in a metal mirror.
# N-type GaAs(Si,B) is commercially grown as 10 kg crystal ingots and sliced into thin wafers as substrates for electronic circuits. Boron oxide is used as an encapsulant to prevent the loss of arsenic during crystal growth, but also has the benefit of providing boron acceptors for scintillation. | 0 | Theoretical and Fundamental Chemistry |
Monochromatic light is illuminated vertically on the rear side of a transparent multi-layer substrate. The partial beams of the monochromatic light are transmitted and reflected at each interphase of the multi-layer system. Superimposition of the reflected beams result in destructive or constructive interference (depending on wavelength of the used light and the used substrate/multi-layer system materials) that can be detected in an intensity change of the reflected light using a photodiode, CCD, or CMOS element.
The sensitive layer on top of the multi-layer system can be (bio-)chemically modified with receptor molecules, e.g. antibodies. Binding of specific ligands to the immobilised receptor molecules results in a change refractive index n and physical thickness d of the sensitive layer. The product of n and d results in the optical thickness (n*d) of the sensitive layer.
Monitoring the change of the reflected intensity of the used light over time results in binding curves that provide information on:
* concentration of used ligand
* binding kinetics (association and dissociation rate constants) between receptor and ligand
* binding strength (affinity) between receptor and ligand
* specificity of the interaction between receptor and ligand
Compared to bio-layer interferometry, which monitors the change of the interference pattern of reflected white light, SCORE only monitors the intensity change of the reflected light using a photodiode, CCD, or CMOS element. Thus, it is possible to analyse not only a single interaction but high-density arrays with up to 10,000 interactions per cm.
Compared to surface plasmon resonance (SPR), which penetration depth is limited by the evanescent field, SCORE is limited by the coherence length of the light source, which is typically a few micrometers. This is especially relevant when investigating whole cell assays. Also, SCORE (as well as BLI) is not influenced by temperature fluctuations during the measurement, while SPR needs thermostabilisation. | 0 | Theoretical and Fundamental Chemistry |
Treatment of high-silicon ferrosilicon with hydrogen chloride is the basis of the industrial synthesis of trichlorosilane.
Ferrosilicon is also used in a ratio of 3–3.5% in the manufacture of sheets for the magnetic circuit of electrical transformers. | 1 | Applied and Interdisciplinary Chemistry |
Like carbon, silicon can form four stable bonds with itself and other elements, and long chemical chains known as silane polymers, which are very similar to the hydrocarbons essential to life on Earth. Silicon is more reactive than carbon, which could make it optimal for extremely cold environments. However, silanes spontaneously burn in the presence of oxygen at relatively low temperatures, so an oxygen atmosphere may be deadly to silicon-based life. On the other hand, it is worth considering that alkanes are as a rule quite flammable, but carbon-based life on Earth does not store energy directly as alkanes, but as sugars, lipids, alcohols, and other hydrocarbon compounds with very different properties. Water as a solvent would also react with silanes, but again, this only matters if for some reason silanes are used or mass-produced by such organisms.
Silicon lacks an important property of carbon: single, double, and triple carbon-carbon bonds are all relatively stable. Aromatic carbon structures underpin DNA, which could not exist without this property of carbon. By comparison, compounds containing silene double bonds (such as silabenzene, an unstable analogue of benzene) exhibit far lower stability than the equivalent carbon compound. A pair of silane single bonds have significantly greater total enthalpy than a single silene double bond, so simple disilenes readily autopolymerise, and silicon favors the formation of linear chains of single bonds (see the double bond rule).
Hydrocarbons and organic compounds are abundant in meteorites, comets, and interstellar clouds, while their silicon analogs have never been observed in nature. Silicon does, however, form complex one-, two- and three-dimensional polymers in which oxygen atoms form bridges between silicon atoms. These are termed silicates. They are both stable and abundant under terrestrial conditions, and have been proposed as a basis for a pre-organic form of evolution on Earth (see clay hypothesis). | 1 | Applied and Interdisciplinary Chemistry |
Major developments: Bomb shells gain an iron casing. Fire lances are equipped with projectiles and reusable iron barrels. Rockets are used in warfare. "Fire emitting tubes" are produced in the Song dynasty by the mid-13th century and hand cannons are recorded to have been used in battle by the Yuan dynasty in 1287. The earliest extant cannons appear in China. The Mongols spread gunpowder weaponry to Japan, Southeast Asia, and possibly the Middle East as well as Europe. Europe and India both acquire gunpowder by the end of the century, but only in the Middle East are gunpowder weapons mentioned in any detail. | 1 | Applied and Interdisciplinary Chemistry |
Since thermal bumps can either cool or heat the chip depending on the current direction, they can be used to provide precision control of temperature for chips that must operate within specific temperature ranges irrespective of ambient conditions. For example, this is a common problem for many optoelectronic components. | 0 | Theoretical and Fundamental Chemistry |
Porous glass is glass that includes pores, usually in the nanometre- or micrometre-range, commonly prepared by one of the following processes: through metastable phase separation in borosilicate glasses (such as in their system SiO-BO-NaO), followed by liquid extraction of one of the formed phases; through the sol-gel process; or simply by sintering glass powder.
The specific properties and commercial availability of porous glass make it one of the most extensively researched and characterized amorphous solids. Due to the possibility of modeling the microstructure, porous glasses have a high potential as a model system. They show a high chemical, thermal and mechanical resistance, which results from a rigid and incompressible silica network. They can be produced in high quality and with pore sizes ranging from 1 nm up to any desired value. An easy functionalization of the inner surface opens a wide field of applications for porous glasses.
A further special advantage of porous glasses compared to other porous materials, is that they can be made not only as powder or granulate, but also as larger pieces in almost any user defined shape and texture. | 0 | Theoretical and Fundamental Chemistry |
Infrared absorption band positions may be given either in wavelength (usually in micrometers, μm) or wavenumber (usually in reciprocal centimeters, cm) scale. | 0 | Theoretical and Fundamental Chemistry |
Left to equilibration, many compositions will form a uniform single phase, but depending on the temperature and pressure even a single substance may separate into two or more distinct phases. Within each phase, the properties are uniform but between the two phases properties differ.
Water in a closed jar with an air space over it forms a two-phase system. Most of the water is in the liquid phase, where it is held by the mutual attraction of water molecules. Even at equilibrium molecules are constantly in motion and, once in a while, a molecule in the liquid phase gains enough kinetic energy to break away from the liquid phase and enter the gas phase. Likewise, every once in a while a vapor molecule collides with the liquid surface and condenses into the liquid. At equilibrium, evaporation and condensation processes exactly balance and there is no net change in the volume of either phase.
At room temperature and pressure, the water jar reaches equilibrium when the air over the water has a humidity of about 3%. This percentage increases as the temperature goes up. At 100 °C and atmospheric pressure, equilibrium is not reached until the air is 100% water. If the liquid is heated a little over 100 °C, the transition from liquid to gas will occur not only at the surface but throughout the liquid volume: the water boils. | 0 | Theoretical and Fundamental Chemistry |
This experiment can be conducted with glow sticks, chalks, and solutions of acetone or isopropyl alcohol.
Drops of glowing fluid from a glow stick are added to a chalk so that a band is created halfway through it. The chalk is then placed vertically into a beaker filled with a small amount of acetone or alcohol - ensuring the surface of the solvent is below the dye band. The liquid is then allowed to travel up the chalk; polar dyes would tend to stick to the chalk and not travel significantly while non-polar dyes would travel up with the solvent. Once it travels almost to the top of the chalk, it is removed from the beaker. The chalk chromatogram, with separation of colours, can then be observed in a dark room.
Additionally, this glomatographic experiment can be done using other materials. For instance, silica gel can be used as the stationary phase together with a solution of nonpolar hexanes acting as the mobile phase. The polar components would be attracted to the polar silanol (Si-OH) groups on the surface of the silica gel, and the nonpolar components would travel further with the hexanes. Further, dyes in glow sticks can also be extracted using liquid carbon dioxide (CO) as an environmentally friendly or green solvent. In this case, non polar dyes would dissolve in the liquid CO and other dyes would be attracted to cotton. | 1 | Applied and Interdisciplinary Chemistry |
Pregnancy-specific biological substances, which include the placenta, umbilical cord, amniotic fluid, and amniotic membrane are being studied for a number of health uses. For example, Placental-derived stem cells are being studied so they can serve as a potential treatment method for cell therapy. Hepatocyte-like cells (HLC) are generated from differentiated human amniotic epithelial cells (hAEC) that are abundant in the placenta. HLC may replace hepatocytes for hepatocyte transplantation to treat acute or chronic liver damage.
Recent research has shown that the placenta and placenta derivatives are being regenerative cell therapies and also includes immunological features. Placenta structures consist of unique physiognomies. Placenta's structure not only regulates its function but also gives the probability of efficient use in clinics and in biotechnology.
According to a research study by Bhattacharya N., Anemia caused by Diabetes mellitus in patients with albuminuria can be treated with cord blood transfusion. The research showed increased in albumin per gram of creatinine that assessed for albuminuria for patients that received cord blood transfusions. | 1 | Applied and Interdisciplinary Chemistry |
Jonathan David Sarfati (born 1 October 1964) is a young Earth creationist who writes articles for Creation Ministries International (CMI), a non-profit Christian apologetics ministry. Sarfati has a PhD in chemistry, and was New Zealand national chess champion in 1987 and 1988. | 0 | Theoretical and Fundamental Chemistry |
Certain NMTs are therapeutic targets for development of drugs against bacterial infections. Myristoylation has been shown to be necessary for the survival of a number of disease-causing fungi, among them C. albicans and C. neoformans. In addition to prokaryotic bacteria, the NMTs of numerous disease-causing eukaryotic organisms have been identified as drug targets as well. Proper NMT functioning in the protozoa Leishmania major and Leishmania donovani (leishmaniasis), Trypanosoma brucei (African sleeping sickness), and P. falciparum (malaria) is necessary for survival of the parasites. Inhibitors of these organisms are under current investigation. A pyrazole sulfonamide inhibitor has been identified that selectively binds T. brucei, competing for the peptide binding site, thus inhibiting enzymatic activity and eliminating the parasite from the bloodstream of mice with African sleeping sickness. | 1 | Applied and Interdisciplinary Chemistry |
*Auburn University
*University of Georgia (Biochemical Engineering)
*Michigan Technological University
*McMaster University
*Technical University of Munich
*University of Natural Resources and Life Sciences, Vienna
*Keck Graduate Institute of Applied Life Sciences (KGI Amgen Bioprocessing Center)
*Kungliga Tekniska högskolan- KTH – Royal Institute of Technology (Dept. of Industrial Biotechnology)
*Queensland University of Technology (QUT)
*University of Cape Town (Centre for Bioprocess Engineering Research)
*SUNY-ESF (Bioprocess Engineering Program)
*Université de Sherbrooke
*University of British Columbia
*UC Berkeley
*UC Davis
*Savannah Technical College
*University of Illinois Urbana-Champaign (Integrated Bioprocessing Research Laboratory)
*University of Iowa (Chemical and Biochemical Engineering)
*University of Minnesota (Bioproducts and Biosystems Engineering)
*East Carolina University
*Jacob School of Biotechnology and Bioengineering, Allahabad, India
*Indian Institute of Technology, Varanasi
* Indian Institute of Technology Kharagpur
*Institute of Chemical Technology, Mumbai
*Jadavpur University
* Universidade Federal de Itajubá (UNIFEI)
* Universiti Malaysia Kelantan (UMK)
*Universidade Federal de São João del Rei-UFSJ
*Federal University of Technology – Paraná
*Universidade Federal do Paraná-UFPR
*São Paulo State University
*Universidade Federal do Pará-UFPA
*University of Louvain (UCLouvain)
*University of Stellenbosch
*North Carolina Agricultural and Technical State University
*North Carolina State University
*Virginia Tech
*Ege University/Turkey (Department of Bioengineering)
*National University of Costa Rica
*University of Brawijaya (Department of Agricultural Engineering)
*University of Indonesia
*University College London (Department of Biochemical Engineering)
*Universiti Teknologi Malaysia
*Universiti Kuala Lumpur Malaysian Institute of Chemical and Bioengineering Technology
*University of Zagreb, Faculty of food technology and biotechnology, Croatia
*Villanova University
*Wageningen University
*University College Dublin
*Obafemi Awolowo University
*University of Birmingham
*Universidad Autónoma de Coahuila (Facultad de Ciencias Biológicas)
*Silpakorn University Thailand
*Universiti Malaysia Perlis (UniMAP), School of Bioprocess Engineering (SBE)
*Berlin University of Technology, Chair of Bioprocess Engineering
*University of Queensland
*Technical University of Denmark, Department of Chemical and Biochemical Engineering, BioEng Research Centre
*South Dakota School of Mines and Technology
*National Institute of Applied Science and Technology Tunis (Industrial Biology Engineering Program)
*Technical University Hamburg (TUHH)
*Mapua University | 1 | Applied and Interdisciplinary Chemistry |
Theodore Cohen (May 11, 1929 – December 13, 2017) was an American organic chemist and chemistry professor at University of Pittsburgh. He is known for his research on organic chemistry, and particularly on organosulfur compounds, on organometallic chemistry, and on the synthesis of phenols. | 0 | Theoretical and Fundamental Chemistry |
The Wilfley Table is commonly used for the concentration of heavy minerals from the laboratory up to the industrial scale. It has a traditional shaking (oscillating) table design with a riffled deck. It is one of several brands of wet tables used for the separation and concentration of heavy ore minerals which include the Deister Table and Holman Table, all built to handle either coarse or fine feeds for mineral processing.
The Wilfley Table became a design used world-wide due to the fact it significantly increased the recovery of silver, gold and other precious metals. Such was the tables widespread use that it was included in Websters Dictionary, and has been in constant use by miners and metallurgists since its invention. | 1 | Applied and Interdisciplinary Chemistry |
Beridze was awarded the Order of Honour of Georgia in 1999. He was awarded the Serge Durmishidze prize in Biochemistry in 2009. | 1 | Applied and Interdisciplinary Chemistry |
A mirror image (in a plane mirror) is a reflected duplication of an object that appears almost identical, but is reversed in the direction perpendicular to the mirror surface. As an optical effect it results from reflection off from substances such as a mirror or water. It is also a concept in geometry and can be used as a conceptualization process for 3-D structures. | 0 | Theoretical and Fundamental Chemistry |
The majority of mRNAs in E. coli are prefaced with a Shine-Dalgarno (SD) sequence. The SD sequence is recognized by an complementary "anti-SD" region on the 16S rRNA component of the 30S subunit. In the canonical model, the 30S ribosome is first joined up with the three initiation factors, forming an unstable "pre-initiation complex". The mRNA then pairs up with this anti-SD region, causing it to form a double-stranded RNA structure, roughly positioning the start codon at the P site. An initiating tRNA arrives and is positioned with the help of IF2, starting the translation.
There are a lot of uncertainties even in the canonical model. The initiation site has been shown to be not strictly limited to AUG. Well-known coding regions that do not have AUG initiation codons are those of lacI (GUG) and lacA (UUG) in the E. coli lac operon. Two studies have independently shown that 17 or more non-AUG start codons may initiate translation in E. coli. Nevertheless, AUG seems to at least be the strongest initiation codon among all possibilities.
The SD sequence also does not appear strictly necessary, as a wide range of mRNAs lack them and are still translated, with an entire phylum of bacteria (Bacteroidetes) using no such sequence. Simply SD followed by AUG is also not sufficient to initiate translation. It does, at least, function as a very important initiating signal in E. coli. | 1 | Applied and Interdisciplinary Chemistry |
The most known and widely used theory for calculating zeta potential from experimental data is that developed by Marian Smoluchowski in 1903. This theory was originally developed for electrophoresis; however, an extension to electroacoustics is now also available. Smoluchowski's theory is powerful because it is valid for dispersed particles of any shape and any concentration. However, it has its limitations:
*Detailed theoretical analysis proved that Smoluchowski's theory is valid only for a sufficiently thin double layer, when the Debye length, , is much smaller than the particle radius, :
:The model of the "thin double layer" offers tremendous simplifications not only for electrophoresis theory but for many other electrokinetic and electroacoustic theories. This model is valid for most aqueous systems because the Debye length is typically only a few nanometers in water. The model breaks only for nano-colloids in a solution with ionic strength approaching that of pure water.
*Smoluchowski's theory neglects the contribution of surface conductivity. This is expressed in modern theories as the condition of a small Dukhin number:
The development of electrophoretic and electroacoustic theories with a wider range of validity was a purpose of many studies during the 20th century. There are several analytical theories that incorporate surface conductivity and eliminate the restriction of the small Dukhin number for both the electrokinetic and electroacoustic applications.
Early pioneering work in that direction dates back to Overbeek and Booth.
Modern, rigorous electrokinetic theories that are valid for any zeta potential, and often any , stem mostly from Soviet Ukrainian (Dukhin, Shilov, and others) and Australian (OBrien, White, Hunter, and others) schools. Historically, the first one was Dukhin–Semenikhin theory. A similar theory was created ten years later by OBrien and Hunter. Assuming a thin double layer, these theories would yield results that are very close to the numerical solution provided by O'Brien and White. There are also general electroacoustic theories that are valid for any values of Debye length and Dukhin number. | 0 | Theoretical and Fundamental Chemistry |
In the specific case of antibodies (Ab) binding to antigen (Ag), usually the term affinity constant refers to the association constant.
This chemical equilibrium is also the ratio of the on-rate (k or k) and off-rate (k or k) constants. Two antibodies can have the same affinity, but one may have both a high on- and off-rate constant, while the other may have both a low on- and off-rate constant. | 0 | Theoretical and Fundamental Chemistry |
In order to enable fast and efficient transduction of electrical signals in the nervous system, certain neuronal axons are covered with myelin sheaths. Myelin is a multilamellar membrane that enwraps the axon in segments separated by intervals known as nodes of Ranvier. It is produced by specialized cells: Schwann cells exclusively in the peripheral nervous system, and oligodendrocytes exclusively in the central nervous system. Myelin sheath reduces membrane capacitance and increases membrane resistance in the inter-node intervals, thus allowing a fast, saltatory movement of action potentials from node to node. Myelination is found mainly in vertebrates, but an analogous system has been discovered in a few invertebrates, such as some species of shrimp. Not all neurons in vertebrates are myelinated; for example, axons of the neurons comprising the autonomous nervous system are not, in general, myelinated.
Myelin prevents ions from entering or leaving the axon along myelinated segments. As a general rule, myelination increases the conduction velocity of action potentials and makes them more energy-efficient. Whether saltatory or not, the mean conduction velocity of an action potential ranges from 1 meter per second (m/s) to over 100 m/s, and, in general, increases with axonal diameter.
Action potentials cannot propagate through the membrane in myelinated segments of the axon. However, the current is carried by the cytoplasm, which is sufficient to depolarize the first or second subsequent node of Ranvier. Instead, the ionic current from an action potential at one node of Ranvier provokes another action potential at the next node; this apparent "hopping" of the action potential from node to node is known as saltatory conduction. Although the mechanism of saltatory conduction was suggested in 1925 by Ralph Lillie, the first experimental evidence for saltatory conduction came from Ichiji Tasaki and Taiji Takeuchi and from Andrew Huxley and Robert Stämpfli. By contrast, in unmyelinated axons, the action potential provokes another in the membrane immediately adjacent, and moves continuously down the axon like a wave.
Myelin has two important advantages: fast conduction speed and energy efficiency. For axons larger than a minimum diameter (roughly 1 micrometre), myelination increases the conduction velocity of an action potential, typically tenfold. Conversely, for a given conduction velocity, myelinated fibers are smaller than their unmyelinated counterparts. For example, action potentials move at roughly the same speed (25 m/s) in a myelinated frog axon and an unmyelinated squid giant axon, but the frog axon has a roughly 30-fold smaller diameter and 1000-fold smaller cross-sectional area. Also, since the ionic currents are confined to the nodes of Ranvier, far fewer ions "leak" across the membrane, saving metabolic energy. This saving is a significant selective advantage, since the human nervous system uses approximately 20% of the body's metabolic energy.
The length of axons' myelinated segments is important to the success of saltatory conduction. They should be as long as possible to maximize the speed of conduction, but not so long that the arriving signal is too weak to provoke an action potential at the next node of Ranvier. In nature, myelinated segments are generally long enough for the passively propagated signal to travel for at least two nodes while retaining enough amplitude to fire an action potential at the second or third node. Thus, the safety factor of saltatory conduction is high, allowing transmission to bypass nodes in case of injury. However, action potentials may end prematurely in certain places where the safety factor is low, even in unmyelinated neurons; a common example is the branch point of an axon, where it divides into two axons.
Some diseases degrade myelin and impair saltatory conduction, reducing the conduction velocity of action potentials. The most well-known of these is multiple sclerosis, in which the breakdown of myelin impairs coordinated movement. | 0 | Theoretical and Fundamental Chemistry |
In exceptional circumstances, typically during emergencies such as dike breaches, efforts are made to seal the breach by manoeuvring a ship into it. Often, this method fails due to the mismatch between the dimensions of the ship and the breach. Instances have been recorded where the ship, once directed into the breach, was then dislodged by the powerful current. Another frequent issue is the incompatibility of the ship's bottom with the seabed of the breach, leading to undermining. The ensuing strong current further erodes the seabed beneath the ship, rendering the closure attempt unsuccessful. A notable exception occurred in 1953 during a dike breach along the Hollandse IJssel, which was successfully sealed; a monument commemorates this event later.
In Korea, an attempt was made in 1980 to close a tidal inlet using an old oil tanker. Little information is available about the outcome of this attempt, suggesting it may not have been notably successful, especially considering the numerous subsequent closures in Korea that have utilized stone. Later Google Earth imagery indicates that the ship was eventually removed following the dam's closure. | 1 | Applied and Interdisciplinary Chemistry |
* Conversion coating
** Autophoretic, the registered trade name of a proprietary series of auto-depositing coatings specifically for ferrous metal substrates
** Anodising
** Chromate conversion coating
** Plasma electrolytic oxidation
** Phosphate (coating)
* Ion beam mixing
* Pickled and oiled, a type of plate steel coating
* Plating
** Electroless plating
** nickel plating coating using a different material to preserve mechanical properties
** Electroplating | 1 | Applied and Interdisciplinary Chemistry |
These compounds give a permanent froth when shaken with water. They also cause hemolysis of red blood cells. Saponin glycosides are found in liquorice. Their medicinal value is due to their expectorant, corticoid and anti-inflammatory effects. Steroid saponins are important starting material for the production of semi-synthetic glucocorticoids and other steroid hormones such as progesterone; for example in Dioscorea wild yam the sapogenin diosgenin, in the form of its glycoside dioscin. The ginsenosides are triterpene glycosides and ginseng saponins from Panax ginseng (Chinese ginseng) and Panax quinquefolius (American ginseng). In general, the use of the term saponin in organic chemistry is discouraged, because many plant constituents can produce foam, and many triterpene-glycosides are amphipolar under certain conditions, acting as a surfactant. More modern uses of saponins in biotechnology are as adjuvants in vaccines: Quil A and its derivative QS-21, isolated from the bark of Quillaja saponaria Molina, to stimulate both the Th1 immune response and the production of cytotoxic T-lymphocytes (CTLs) against exogenous antigens make them ideal for use in subunit vaccines and vaccines directed against intracellular pathogens as well as for therapeutic cancer vaccines but with the aforementioned side-effect of hemolysis. Saponins are also natural ruminal antiprotozoal agents that are potential to improve ruminal microbial fermentation reducing ammonia concentrations and methane production in ruminant animals. | 0 | Theoretical and Fundamental Chemistry |
The Grove cell was an early electric primary cell named after its inventor, Welsh physical scientist William Robert Grove, and consisted of a zinc anode in dilute sulfuric acid and a platinum cathode in concentrated nitric acid, the two separated by a porous ceramic pot. | 0 | Theoretical and Fundamental Chemistry |
* between any kind of biomolecules including proteins, DNA, RNA, peptides, small molecules, fragments and ions
* for interactions with high molecular weight complexes, large molecule assemblies, even with liposomes, vesicles, nanodiscs, nanoparticles and viruses
* in any buffer, including serum and cell lysate
* in competition experiments (for example with substrate and inhibitors)
Stoichiometry | 1 | Applied and Interdisciplinary Chemistry |
Production of prebiotic organic compounds at hydrothermal vents is estimated to be 1x10 kg yr. While a large amount of key prebiotic compounds, such as methane, are found at vents, they are in far lower concentrations than estimates of a Miller-Urey Experiment environment. In the case of methane, the production rate at vents is around 2-4 orders of magnitude lower than predicted amounts in a Miller-Urey Experiment surface atmosphere.
Other arguments against an oceanic vent setting for the origin of life include the inability to concentrate prebiotic materials due to strong dilution from seawater. This open-system cycles compounds through minerals that make up vents, leaving little residence time to accumulate. All modern cells rely on phosphates and potassium for nucleotide backbone and protein formation respectively, making it likely that the first life forms also shared these functions. These elements were not available in high quantities in the Archaean oceans as both primarily come from the weathering of continental rocks on land, far from vent settings. Submarine hydrothermal vents are not conducive to condensation reactions needed for polymerisation to form macromolecules. Further, these polymers were encapsulated in vesicles after condensation, which would not happen in saltwater because of the high concentrations of ions. | 0 | Theoretical and Fundamental Chemistry |
In March 2013, NASA reported Curiosity found evidence that geochemical conditions in Gale Crater were once suitable for microbial life after analyzing the first drilled sample of Martian rock, "John Klein" rock at Yellowknife Bay in Gale Crater. The rover detected water, carbon dioxide, oxygen, sulfur dioxide and hydrogen sulfide. Chloromethane and dichloromethane were also detected. Related tests found results consistent with the presence of smectite clay minerals. | 0 | Theoretical and Fundamental Chemistry |
Due to geometry of non-circular conduits, the Fanning friction factor can be estimated from algebraic expressions above by using hydraulic radius when calculating for Reynolds number | 1 | Applied and Interdisciplinary Chemistry |
In a 2007 article the authors claim inter-linking of rivers to initially appear to be a costly proposition in ecological, geological, hydrological and economical terms, but in the long run the net benefits coming from it will far outweigh these costs or losses. However, they suggest that there is a lack of an international legal framework for the projects India is proposing. In at least some inter-link projects, neighbouring countries such as Bangladesh may be affected, and international concerns for the project must be negotiated. | 1 | Applied and Interdisciplinary Chemistry |
Transcription factor II F (TFF) is one of several general transcription factors that make up the RNA polymerase II preinitiation complex.
TFF is encoded by the , , and genes.
TFF binds to RNA polymerase II when the enzyme is already unbound to any other transcription factor, thus preventing it from contacting DNA outside the promoter. Furthermore, TFF stabilizes the RNA polymerase II while it's contacting TBP and TFB. | 1 | Applied and Interdisciplinary Chemistry |
The concept of a thermodynamic template is demonstrated in scheme 1. A thermodynamic template is a reagent that can stabilize the form of one product over others by lowering its Gibbs free energy (ΔG°) in relation to other products. cyclophane C2 can be prepared by the irreversible highly diluted reaction of a diol with chlorobromomethane in the presence of sodium hydride. The dimer however is part of series of equilibria between polyacetal macrocycles of different size brought about by acid catalyzed (triflic acid) transacetalization. Regardless of the starting material, C2, C4 or a high molar mass product, the equilibrium will eventually produce a product distribution across many macrocycles and oligomers. In this system it is possible to amplify' the presence of C2 in the mixture when the transacetalisation catalyst is silver triflate because the silver ion fits ideally and irreversibly in the C2 cavity. | 0 | Theoretical and Fundamental Chemistry |
The general mechanism is shown below. The resonating arrow (1) shows a resonance contributor of the diazo compound with a lone pair of electrons on the carbon adjacent to the nitrogen. The diazo compound then does a nucleophilic attack on the carbonyl-containing compound (nucleophilic addition), producing a tetrahedral intermediate (2). This intermediate decomposes by the evolution of nitrogen gas forming the tertiary carbocation intermediate (3).
The reaction is then completed either by the reformation of the carbonyl through an 1,2-rearrangement or by the formation of the epoxide. There are two possible carbonyl products: one formed by migration of R (4) and the other by migration of R (5). The relative yield of each possible carbonyl is determined by the migratory preferences of the R-groups.
The epoxide product is formed by an intramolecular addition reaction in which a lone pair from the oxygen attacks the carbocation (6).
This reaction is exothermic due to the stability of nitrogen gas and the carbonyl containing compounds. This specific mechanism is supported by several observations. First, kinetic studies of reactions between diazomethane and various ketones have shown that the overall reaction follows second order kinetics. Additionally, the reactivity of two series of ketones are in the orders ClCCOCH > CHCOCH > CHCOCH and cyclohexanone > cyclopentanone > cycloheptanone > cyclooctanone. These orders of reactivity are the same as those observed for reactions that are well established as proceeding through nucleophilic attack on a carbonyl group. | 0 | Theoretical and Fundamental Chemistry |
French drains are often installed around a home foundation in two different ways, or in combination of both:
* Buried around the external side of the foundation wall
* Installed underneath the basement floor on the inside perimeter of the basement
In most homes, an external French drain or drain tile is installed around the foundation walls before the foundation soil is backfilled. It is laid on the bottom of the excavated area, and a layer of stone is laid on top. In many cases, a filter fabric is then laid on top of the stone to keep fine sediments and particles from entering. Once the drain is installed, the area is backfilled, and the system is left alone until it clogs. | 1 | Applied and Interdisciplinary Chemistry |
Bioleaching is the extraction or liberation of metals from their ores through the use of living organisms. Bioleaching is one of several applications within biohydrometallurgy and several methods are used to treat ores or concentrates containing copper, zinc, lead, arsenic, antimony, nickel, molybdenum, gold, silver, and cobalt.
Bioleaching falls into two broad categories. The first, is the use of microorganisms to oxidize refractory minerals to release valuable metals such and gold and silver. Most commonly the minerals that are the target of oxidization are pyrite and arsenopyrite.
The second category is leaching of sulphide minerals to release the associated metal, for example, leaching of pentlandite to release nickel, or the leaching of chalcocite, covellite or chalcopyrite to release copper. | 1 | Applied and Interdisciplinary Chemistry |
FS 49 C2 acts similarly to an inert gas. It absorbs the heat produced from the combustion process. This mechanism is consistent with the observation that the fire heat release rate does not decrease until sufficient gas is released.
The difference from inert gases and FS 49 C2 is that it takes less gas to suppress a fire, and therefore gas storage takes less space, depending on the storage pressure. Savings may vary between a 50-90%. | 1 | Applied and Interdisciplinary Chemistry |
At ambient conditions calcium disilicide exists in two polymorphs, hR9 and hR18; in the hR18 structure the hR9 unit cell is stacked twice along the c axis. Upon heating to 1000 °C at a pressure of ca. 40 kBar, calcium disilicide converts to a (semi-stable) tetragonal phase. The tetragonal phase is a superconductor with a transition temperature of 1.37 K to 1.58 K. Although there is no observable superconducting transition temperature for the trigonal/rhombohedral (i.e. hR9 and hR18 unit cells) at ambient pressure, under high pressure (>12 GPa/120 kbar) this phase has been observed exhibit superconducting transition. When the trigonal phase is placed under pressures exceeding 16 GPa, there is a phase transition to an AlB-like phase. | 1 | Applied and Interdisciplinary Chemistry |
Studies testing prophylactic use of lithium in cluster headaches (when compared to verapamil), migraine attacks and hypnic headache indicate good efficacy. | 1 | Applied and Interdisciplinary Chemistry |
In vertebrates, the region of the mRNA that codes for the signal peptide (i.e. the signal sequence coding region, or SSCR) can function as an RNA element with specific activities. SSCRs promote nuclear mRNA export and the proper localization to the surface of the endoplasmic reticulum. In addition SSCRs have specific sequence features: they have low adenine-content, are enriched in certain motifs, and tend to be present in the first exon at a frequency that is higher than expected. | 1 | Applied and Interdisciplinary Chemistry |
Liquid, submerged and solid state fermentation are age-old techniques used for the preservation and manufacturing of foods. During the second half of the twentieth century, liquid state fermentation developed on an industrial scale to manufacture vital metabolites such as antibiotics.
Economic changes and growing environmental awareness generate new perspectives for solid state fermentation. SSF adds value to insoluble agricultural byproducts thanks to its higher energy efficiency and reduced water consumption.
The renewal of SSF is now possible thanks to engineering firms, mainly from Asia, that have developed a new generation of equipment. Fujiwara makes vessels able to transform substrate areas up to for the production of soy sauce or sake. Other companies use solid state fermentation for enzyme complexes. In France Lyven has manufactured Pectinases and Hemicellulases on beet pulp and wheat bran since 1980. The company (now part of Soufflet Group) is now involved in a global R&D programme focusing on SSF technology. | 1 | Applied and Interdisciplinary Chemistry |
*Crankshaft reconditioning or conditioning
*Corrosion protection
*Fouling protection
*Altering thermal conductivity or electrical conductivity
*Wear control: either hardfacing (wear-resistant) or abradable coating
*Repairing damaged surfaces
*Temperature/oxidation protection (thermal barrier coatings)
*Medical implants coatings (by using polymer derived ceramics)
*Production of functionally graded materials (for any of the above applications) | 1 | Applied and Interdisciplinary Chemistry |
mEosFP is another monomeric Eos variant that folds effectively at 37 degrees Celsius. Where tdEos (tandem dimer) cannot fuse to targets such as histones, tubulin, intermediate filaments and gap junctions, and mEos (monomeric) which can only be used successfully at 30 degrees Celsius, mEos2 is an engineered variant that can fold effectively at 37 degrees Celsius and successfully label targets intolerant to fusion from other fluorescent protein dimers . mEos2 shows almost identical spectral properties, brightness, pKa, photoconversion, contrast and maturation properties to WT Eos. The localization precision of mEos2 is twice as great as other monomeric fluorescent proteins. | 1 | Applied and Interdisciplinary Chemistry |
The scleraxis protein is a member of the basic helix-loop-helix (bHLH) superfamily of transcription factors. Currently two genes ( and respectively) have been identified to code for identical scleraxis proteins. | 1 | Applied and Interdisciplinary Chemistry |
He is credited with writing the following episodes, along with Jack Black, David Cross, Kyle Gass, Tom Gianas, and Bob Odenkirk:
*"Death of a Dream"
*"The Greatest Song in the World"
*"The Fan"
*"Road Gig" | 0 | Theoretical and Fundamental Chemistry |
*Terne-plate is a similar product to tinplate, but the bath is not of tin, but of tin and lead mixed, the latter metal constituting from 7.59% of the whole. The name derives from "terne", meaning dull or tarnish. Terne-plates began to be produced in England about the middle of the 19th century, and became widely employed in the United States for roofing purposes. Other applications included fuel tanks and gas meters. The last Terne-plate mill in Brockmoor, West Midlands in the UK was closed in 2006.[https://www.expressandstar.com/news/business/2006/11/14/corus-axes-steel-plant/]
*For many purposes, tinplate has been replaced by galvanised (zinc-coated) vessels - though not for cooking, as zinc can be toxic. A Zinc protects iron electrolytically, that is, the zinc will oxidise and turn to a white powder to preserve the iron, whereas tin will only protect the iron if the tin-surface remains unbroken, as it electrolytically cannibalises unprotected iron to preserve itself. | 1 | Applied and Interdisciplinary Chemistry |
The mass number gives an estimate of the isotopic mass measured in atomic mass units (u). For C, the isotopic mass is exactly 12, since the atomic mass unit is defined as 1/12 of the mass of C. For other isotopes, the isotopic mass is usually within 0.1 u of the mass number. For example, Cl (17 protons and 18 neutrons) has a mass number of 35 and an isotopic mass of 34.96885. The difference of the actual isotopic mass minus the mass number of an atom is known as the mass excess, which for Cl is –0.03115. Mass excess should not be confused with mass defect which is the difference between the mass of an atom and its constituent particles (namely protons, neutrons and electrons).
There are two reasons for mass
excess:
# The neutron is slightly heavier than the proton. This increases the mass of nuclei with more neutrons than protons relative to the atomic mass unit scale based on C with equal numbers of protons and neutrons.
# Nuclear binding energy varies between nuclei. A nucleus with greater binding energy has a lower total energy, and therefore a lower mass according to Einsteins mass–energy equivalence relation E = mc'. For Cl, the isotopic mass is less than 35, so this must be the dominant factor. | 0 | Theoretical and Fundamental Chemistry |
Nucleic acid sequence-based amplification, commonly referred to as NASBA, is a method in molecular biology which is used to produce multiple copies of single stranded RNA. NASBA is a two-step process that takes RNA and anneals specially designed primers, then utilizes an enzyme cocktail to amplify it. | 1 | Applied and Interdisciplinary Chemistry |
Dexmedetomidine, under the trade name Dexdomitor (Orion Corporation), was approved in the European Union in for use in cats and dogs in 2002, for sedation and induction of general anesthesia. The FDA approved dexmedetomidine for use in dogs in 2006 and cats in 2007.
In 2015, the European Medicines Agency and the FDA approved an oromucosal gel form of dexmedetomidine marketed as Sileo (Zoetis) for use in dogs for relief of noise aversion. | 0 | Theoretical and Fundamental Chemistry |
When stored in air, it forms a yellow potassium superoxide coating and may ignite. This superoxide reacts explosively with water and organics. NaK is not dense enough to sink in most hydrocarbons, but will sink in lighter mineral oil. It is unsafe to store in this manner if the superoxide has formed. A large explosion took place at the Oak Ridge Y-12 facility on December 8, 1999, when NaK cleaned up after an accidental spill and inappropriately treated with mineral oil was scratched with a metal tool. The liquid alloy also attacks PTFE ("Teflon"). | 1 | Applied and Interdisciplinary Chemistry |
The self-similar solution is obtained by introducing the transformation
the equation reduces to
while the boundary conditions become
The exact solution is given by
where is solved from the following equation
Letting
the velocity is given by
The mass flow rate across a plane at a distance from the orifice normal to the jet is | 1 | Applied and Interdisciplinary Chemistry |
Robert Guillaumont is a specialist in radiochemistry and actinide chemistry. He prepared his doctorate at the Institut radium de Paris, Curie Laboratory, University of Paris VI (1966). He continued his research in this Institute and then at the Radiochemistry Laboratory of the Orsay (1968–98), which he directed for twelve years (1979–90). He taught chemistry/radiochemistry at the University of Paris XI-Orsay (1967–98). His expertise covers the chemistry of the nuclear fuel cycle (from uranium mining to waste management and spent fuel reprocessing) and nuclear energy issues. He has been a member or chairman of numerous French and international committees dealing with the nuclear fuel cycle, nuclear energy, radioactive waste management and the synthesis and use of radionuclides for medicine. He was a member of the National Commission for the Evaluation of Research on Nuclear Materials and Radioactive Waste (1994-2019). | 0 | Theoretical and Fundamental Chemistry |
Blue carbon is a concept within climate change mitigation that refers to "biologically driven carbon fluxes and storage in marine systems that are amenable to management." Most commonly, it refers to the role that tidal marshes, mangroves and seagrasses can play in carbon sequestration. These ecosystems can play an important role for climate change mitigation and ecosystem-based adaptation. However, when blue carbon ecosystems are degraded or lost they release carbon back to the atmosphere, thereby adding to greenhouse gas emissions.
The methods for blue carbon management fall into the category of "ocean-based biological carbon dioxide removal (CDR) methods". They are a type of biological carbon fixation.
Scientists are looking for ways to further develop the blue carbon potential of ecosystems. However, the long-term effectiveness of blue carbon as a carbon dioxide removal solution is under debate.
The term deep blue carbon is also in use and refers to storing carbon in the deep ocean waters. | 0 | Theoretical and Fundamental Chemistry |
The isochore theory was the first to identify the nonuniformity of nucleotide composition within vertebrate genomes and predict that the genome of "warm-blooded" vertebrates such as mammals and birds are mosaic of isochores (Bernardi et al. 1985). The human genome, for example, was described as a mosaic of alternating low and high GC content isochores belonging to five compositional families, L1, L2, H1, H2, and H3, whose corresponding ranges of GC contents were said to be <38%, 38%-42%, 42%-47%, 47%-52%, and >52%, respectively.
The main predictions of the isochore theory are that:
* GC content of the third codon position (GC3) of protein coding genes is correlated with the GC content of the isochores embedding the corresponding genes.
* The genome organization of warm-blooded vertebrates is a mosaic of mostly GC-rich isochores.
* Genome organization of cold-blooded vertebrates is characterized by low GC content levels and lower compositional heterogeneity than warm-blooded vertebrates. Homogeneous domains do not reach the high GC levels attained by the genomes of warm-blooded vertebrates. | 1 | Applied and Interdisciplinary Chemistry |
Often, the algae is dehydrated, and then a solvent such as hexane is used to extract energy-rich compounds like triglycerides from the dried material. Then, the extracted compounds can be processed into fuel using standard industrial procedures. For example, the extracted triglycerides are reacted with methanol to create biodiesel via transesterification. The unique composition of fatty acids of each species influences the quality of the resulting biodiesel and thus must be taken into account when selecting algal species for feedstock. | 1 | Applied and Interdisciplinary Chemistry |
Electric resistance corrosion probes are used in different types for different applications of online corrosion monitoring. The corrosion rate of these probes can be measured online or transferred to the control system by using corrosion handheld or fixed data loggers or by corrosion transmitters.
The general type of ER probes element are as below:
* flush type
* cylindrical
* spiral loop
* wire loop
* tube loop
ER probes can be provided by adapter in order to connect to data logger or transmitters. The length of probes is dependent on the mounting and monitoring position. | 1 | Applied and Interdisciplinary Chemistry |
When applied globally, PDRC can lower rising temperatures to slow and reverse global warming. Aili et al. concludes that "widescale adoption of radiative cooling could reduce air temperature near the surface, if not the whole atmosphere." To address global warming, PDRCs must be designed "to ensure that the emission is through the atmospheric transparency window and out to space, rather than just to the atmosphere, which would allow for local but not global cooling."
PDRC is not proposed as a standalone solution to global warming, but to be coupled with a global reduction in emissions and transition off of fossil fuel energy. Otherwise, "the radiative balance will not last long, and the potential financial benefits of mitigation will not fully be realized because of continued ocean acidification, air pollution, and redistribution of biomass" from high remaining levels of atmospheric , as per Munday, who summarized the global implementation of PDRC as follows:The estimated total surface area coverage is 5×10 m or about half the size of the Sahara Desert. Global implementation may be more predictable if distributed in a decentralized manner, rather than in a few heavily centralized locations on the Earth's surface. Mandal et al. refers to this as a "distributed geoengineering" strategy that can mitigate "weather disruptions that may arise from large-scale, centralized geoengineering." Desert climates have the highest radiative cooling potential due to low year-round humidity and cloud cover while tropical climates have a lower cooling potential due to the presence of humidity and cloud cover.
Total costs for global implementation have been estimated at $1.25 to $2.5 trillion or about 3% of global GDP, with probable reductions in price at scale. This has been described as "a small investment compared to the estimated $20 trillion global benefits predicted by limiting global warming to 1.5°C rather than 2°C," as per Munday. Low-cost scalable materials have been developed for widescale implementation, although some challenges toward commercialization remain.
Some studies have recommended efforts to focus on maximizing the solar reflectance or albedo of surfaces from very low values to high values, so long as a thermal emittance of at least 90% can be achieved. For example, while the albedo of an urban rooftop may be 0.2, increasing reflectivity to 0.9 is far more impactful than increasing an already reflective surface to be more reflective, such as from 0.9 to 0.97. | 0 | Theoretical and Fundamental Chemistry |
The technique measures a subjects carbon dioxide production during the interval between first and last body water samples. The method depends on the details of carbon metabolism in our bodies. When cellular respiration breaks down carbon-containing molecules to release energy, carbon dioxide is released as a byproduct. Carbon dioxide contains two oxygen atoms and only one carbon atom, but food molecules such as carbohydrates do not contain enough oxygen to provide both oxygen atoms found in CO. It turns out, one of the two oxygen atoms in CO is derived from body water. If the oxygen in water is labeled with O, then CO produced by respiration will contain labeled oxygen. In addition, as CO travels from the site of respiration through the cytoplasm of a cell, through the interstitial fluids, into the bloodstream and then to the lungs some of it is reversibly converted to bicarbonate. So, after consuming water labeled with O, the O equilibrates with the bodys bicarbonate and dissolved carbon dioxide pool (through the action of the enzyme carbonic anhydrase). As carbon dioxide is exhaled, O is lost from the body. This was discovered by Lifson in 1949. However, O is also lost through body water loss (such as urine and evaporation of fluids). However, deuterium (the second label in the doubly labeled water) is lost only when body water is lost. Thus, the loss of deuterium in body water over time can be used to mathematically compensate for the loss of O by the water-loss route. This leaves only the remaining net loss of O in carbon dioxide. This measurement of the amount of carbon dioxide lost is an excellent estimate for total carbon dioxide production. Once this is known, the total metabolic rate may be estimated from simplifying assumptions regarding the ratio of oxygen used in metabolism (and therefore heat generated), to carbon dioxide eliminated (see respiratory quotient). This quotient can be measured in other ways, and almost always has a value between 0.7 and 1.0, and for a mixed diet is usually about 0.8.
In lay terms:
* Metabolism can be calculated from oxygen-in/CO-out.
* DLW (tagged) water is traceable hydrogen (deuterium), and traceable oxygen (O).
* The O leaves the body in two ways: (i) exhaled CO, and (ii) water loss in (mostly) urine, sweat, & breath.
* But the deuterium leaves only in the second way (water loss).
From deuterium loss, we know how much of the tagged water left the body as water. And, since the concentration of O in the bodys water is measured after the labeling dose is given, we also know how much of the tagged oxygen left the body in the water. (A simpler view is that the ratio of deuterium to O in body water is fixed, so total loss-rate of deuterium from the body multiplied by this ratio, immediately gives the loss rate of O in water.) Measurement of O dilution with time gives the total loss of this isotope by all routes (by water and respiration). Since the ratio of O to total water oxygen in the body is measured, we can convert O loss in respiration to total oxygen lost from the bodys water pool via conversion to carbon dioxide. How much oxygen left the body as CO is the same as the CO produced by metabolism, since the body only produces CO by this route. The CO loss tells us the energy produced, if we know or can estimate the respiratory quotient (ratio of CO produced to oxygen used). | 0 | Theoretical and Fundamental Chemistry |
In the fifth chapter action connected with the body and action connected with the mind are investigated. The text defines and discusses Yoga and Moksha, asserting that self-knowledge (atma-saksatkara) is the means to spiritual liberation. In this chapter, Kanada mentions various natural phenomena such as the falling of objects to ground, rising of fire upwards, the growth of grass upwards, the nature of rainfall and thunderstorms, the flow of liquids, the movement towards a magnet among many others; he then attempts to integrate his observations with his theories, and classifies phenomenon into two: those caused by volition, and those caused by subject-object conjunctions. | 1 | Applied and Interdisciplinary Chemistry |
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