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*Bishan-Ang Mo Kio Park – Singapore
*Potsdamer Platz – Berlin, Germany
*Arkadien Winnenden – Germany
*Tianjin Cultural Park – China
*Holalokka – Oslo, Norway
*McLaren Technology Centre – London, UK
*Pforzheim Water Playground – Germany
*Tanner Springs Park – Portland, USA
*Lanferbach – Gelsenkirchen, Germany
*Maybach Centre of Excellence – Sindelfingen, Germany
*River Volme Renaturation – Hagen, Germany
*City Hall Green Roof – Chicago, USA
*Heiner-Metzger-Platz – Neu-Ulm, Germany
*Residential and commercial complex Prisma – Nuremberg, Germany
*Hafen Offenbach – Offenbach am Main, Germany | 1 | Applied and Interdisciplinary Chemistry |
In fluid dynamics, a gravity current or density current is a primarily horizontal flow in a gravitational field that is driven by a density difference in a fluid or fluids and is constrained to flow horizontally by, for instance, a ceiling. Typically, the density difference is small enough for the Boussinesq approximation to be valid. Gravity currents can be thought of as either finite in volume, such as the pyroclastic flow from a volcano eruption, or continuously supplied from a source, such as warm air leaving the open doorway of a house in winter. Other examples include dust storms, turbidity currents, avalanches, discharge from wastewater or industrial processes into rivers, or river discharge into the ocean.
Gravity currents are typically much longer than they are tall. Flows that are primarily vertical are known as plumes. As a result, it can be shown (using dimensional analysis) that vertical velocities are generally much smaller than horizontal velocities in the current; the pressure distribution is thus approximately hydrostatic, apart from near the leading edge. Gravity currents may be simulated by the shallow water equations, with special dispensation for the leading edge which behaves as a discontinuity. When a gravity current propagates along a plane of neutral buoyancy within a stratified ambient fluid, it is known as a gravity current intrusion. | 1 | Applied and Interdisciplinary Chemistry |
A Folch solution is a solution containing chloroform and methanol, usually in a 2:1 (vol/vol) ratio. One of its uses is in separating polar from nonpolar compounds, for example separating nonpolar lipids from polar proteins and carbohydrates in blood serum. | 0 | Theoretical and Fundamental Chemistry |
In soils, it is assumed that larger amounts of phenols are released from decomposing plant litter rather than from throughfall in any natural plant community. Decomposition of dead plant material causes complex organic compounds to be slowly oxidized lignin-like humus or to break down into simpler forms (sugars and amino sugars, aliphatic and phenolic organic acids), which are further transformed into microbial biomass (microbial humus) or are reorganized, and further oxidized, into humic assemblages (fulvic and humic acids), which bind to clay minerals and metal hydroxides. There has been a long debate about the ability of plants to uptake humic substances from their root systems and to metabolize them. There is now a consensus about how humus plays a hormonal role rather than simply a nutritional role in plant physiology.
In the soil, soluble phenols face four different fates. They might be degraded and mineralized as a carbon source by heterotrophic microorganisms; they can be transformed into insoluble and recalcitrant humic substances by polymerization and condensation reactions (with the contribution of soil organisms); they might adsorb to clay minerals or form chelates with aluminium or iron ions; or they might remain in dissolved form, leached by percolating water, and finally leave the ecosystem as part of dissolved organic carbon (DOC).
Leaching is the process by which cations such as iron (Fe) and aluminum (Al), as well as organic matter, are removed from the litterfall and transported downward into the soil below. This process is known as podzolization and is particularly intense in boreal and cool temperate forests that are mainly constituted by coniferous pines, whose litterfall is rich in phenolic compounds and fulvic acid. | 0 | Theoretical and Fundamental Chemistry |
PKA helps transfer/translate the dopamine signal into cells in the nucleus accumbens, which mediates reward, motivation, and task salience. The vast majority of reward perception involves neuronal activation in the nucleus accumbens, some examples of which include sex, recreational drugs, and food. Protein Kinase A signal transduction pathway helps in modulation of ethanol consumption and its sedative effects. A mouse study reports that mice with genetically reduced cAMP-PKA signalling results into less consumption of ethanol and are more sensitive to its sedative effects. | 1 | Applied and Interdisciplinary Chemistry |
Despite its simplicity, Dulong–Petit law offers fairly good prediction for the heat capacity of many elementary solids with relatively simple crystal structure at high temperatures. This agreement is because in the classical statistical theory of Ludwig Boltzmann, the heat capacity of solids approaches a maximum of 3R per mole of atoms because full vibrational-mode degrees of freedom amount to 3 degrees of freedom per atom, each corresponding to a quadratic kinetic energy term and a quadratic potential energy term. By the equipartition theorem, the average of each quadratic term is kT, or RT per mole (see derivation below). Multiplied by 3 degrees of freedom and the two terms per degree of freedom, this amounts to 3R per mole heat capacity.
The Dulong–Petit law fails at room temperatures for light atoms bonded strongly to each other, such as in metallic beryllium and in carbon as diamond. Here, it predicts higher heat capacities than are actually found, with the difference due to higher-energy vibrational modes not being populated at room temperatures in these substances.
In the very low (cryogenic) temperature region, where the quantum mechanical nature of energy storage in all solids manifests itself with larger and larger effect, the law fails for all substances. For crystals under such conditions, the Debye model, an extension of the Einstein theory that accounts for statistical distributions in atomic vibration when there are lower amounts of energy to distribute, works well. | 0 | Theoretical and Fundamental Chemistry |
Because of their low vapour pressure, PCBs accumulate primarily in the hydrosphere, despite their hydrophobicity, in the organic fraction of soil, and in organisms including the human body. The hydrosphere is the main reservoir. The immense volume of water in the oceans is still capable of dissolving a significant quantity of PCBs.
As the pressure of ocean water increases with depth, PCBs become heavier than water and sink to the deepest ocean trenches where they are concentrated. | 1 | Applied and Interdisciplinary Chemistry |
Ethane-1,2-dithiol is made commercially by the reaction of 1,2-dichloroethane with aqueous sodium bisulfide. In the laboratory, it can also be prepared by the action of 1,2-dibromoethane on thiourea followed by hydrolysis. | 0 | Theoretical and Fundamental Chemistry |
The determination of viscosity is based on Poiseuille's law:
where t is the time it takes for a volume V to elute. The ratio depends on R as the capillary radius, on the average applied pressure P, on its length L and on the dynamic viscosity η.
The average pressure head is given by:
with ρ the density of the liquid, g the Standard gravity and H the average head of the liquid. In this way the viscosity of a fluid can be determined.
Usually the viscosity of a liquid is compared to a liquid with an analyte for example a polymer dissolved in it. The relative viscosity is given by:
where t and ρ are the elution time and density of the pure liquid. When the solution is very diluted
the so-called specific viscosity becomes:
This specific viscosity is related to the concentration of the analyte through the Intrinsic viscosity [η] by the power series:
or
where is called the viscosity number.
The intrinsic viscosity can be determined experimentally by measuring the viscosity number as function of concentration as the Y-axis intercept. | 0 | Theoretical and Fundamental Chemistry |
Unlike end point PCR (conventional PCR), real time PCR allows monitoring of the desired product at any point in the amplification process by measuring fluorescence (in real time frame, measurement is made of its level over a given threshold). A commonly employed method of DNA quantification by real-time PCR relies on plotting fluorescence against the number of cycles on a logarithmic scale. A threshold for detection of DNA-based fluorescence is set 3–5 times of the standard deviation of the signal noise above background. The number of cycles at which the fluorescence exceeds the threshold is called the threshold cycle (C) or, according to the MIQE guidelines, quantification cycle (C).
During the exponential amplification phase, the quantity of the target DNA template (amplicon) doubles every cycle. For example, a DNA sample whose C precedes that of another sample by 3 cycles contained 2 = 8 times more template. However, the efficiency of amplification is often variable among primers and templates. Therefore, the efficiency of a primer-template combination is assessed in a titration experiment with serial dilutions of DNA template to create a standard curve of the change in (C) with each dilution. The slope of the linear regression is then used to determine the efficiency of amplification, which is 100% if a dilution of 1:2 results in a (C) difference of 1. The cycle threshold method makes several assumptions of reaction mechanism and has a reliance on data from low signal-to-noise regions of the amplification profile that can introduce substantial variance during the data analysis.
To quantify gene expression, the (C) for an RNA or DNA from the gene of interest is subtracted from the (C) of RNA/DNA from a housekeeping gene in the same sample to normalize for variation in the amount and quality of RNA between different samples. This normalization procedure is commonly called the ΔC-method and permits comparison of expression of a gene of interest among different samples. However, for such comparison, expression of the normalizing reference gene needs to be very similar across all the samples. Choosing a reference gene fulfilling this criterion is therefore of high importance, and often challenging, because only very few genes show equal levels of expression across a range of different conditions or tissues. Although cycle threshold analysis is integrated with many commercial software systems, there are more accurate and reliable methods of analysing amplification profile data that should be considered in cases where reproducibility is a concern.
Mechanism-based qPCR quantification methods have also been suggested, and have the advantage that they do not require a standard curve for quantification. Methods such as MAK2 have been shown to have equal or better quantitative performance to standard curve methods. These mechanism-based methods use knowledge about the polymerase amplification process to generate estimates of the original sample concentration. An extension of this approach includes an accurate model of the entire PCR reaction profile, which allows for the use of high signal-to-noise data and the ability to validate data quality prior to analysis.
According to research of Ruijter et al. MAK2 assumes constant amplification efficiency during the PCR reaction. However, theoretical analysis of polymerase chain reaction, from which MAK2 was derived, has revealed that amplification efficiency is not constant throughout PCR. While MAK2 quantification provides reliable estimates of target DNA concentration in a sample under normal qPCR conditions, MAK2 does not reliably quantify target concentration for qPCR assays with competimeters. | 1 | Applied and Interdisciplinary Chemistry |
An organic superconductor is a synthetic organic compound that exhibits superconductivity at low temperatures.
As of 2007 the highest achieved critical temperature for an organic superconductor at standard pressure is , observed in the alkali-doped fullerene RbCsC.
In 1979 Klaus Bechgaard synthesized the first organic superconductor (TMTSF)PF (the corresponding material class was named after him later) with a transition temperature of T = 0.9 K, at an external pressure of 11 kbar.
Many materials may be characterized as organic superconductors. These include the Bechgaard salts and Fabre salts which are both quasi-one-dimensional, and quasi-two-dimensional materials such as k-BEDT-TTFX charge-transfer complex, λ-BETSX compounds, graphite intercalation compounds and three-dimensional materials such as the alkali-doped fullerenes.
Organic superconductors are of special interest not only for scientists, looking for room-temperature superconductivity and for model systems explaining the origin of superconductivity but also for daily life issues as organic compounds are mainly built of carbon and hydrogen which belong to the most common elements on earth in contrast to copper or osmium. | 0 | Theoretical and Fundamental Chemistry |
There are about 20,000 known lichen species. But what is meant by "species" is different from what is meant by biological species in plants, animals, or fungi, where being the same species implies that there is a common ancestral lineage. Because lichens are combinations of members of two or even three different biological kingdoms, these components must have a different ancestral lineage from each other. By convention, lichens are still called "species" anyway, and are classified according to the species of their fungus, not the species of the algae or cyanobacteria. Lichens are given the same scientific name (binomial name) as the fungus in them, which may cause some confusion. The alga bears its own scientific name, which has no relationship to the name of the lichen or fungus.
Depending on context, "lichenized fungus" may refer to the entire lichen, or to the fungus when it is in the lichen, which can be grown in culture in isolation from the algae or cyanobacteria. Some algae and cyanobacteria are found naturally living outside of the lichen. The fungal, algal, or cyanobacterial component of a lichen can be grown by itself in culture. When growing by themselves, the fungus, algae, or cyanobacteria have very different properties than those of the lichen. Lichen properties such as growth form, physiology, and biochemistry, are very different from the combination of the properties of the fungus and the algae or cyanobacteria.
The same fungus growing in combination with different algae or cyanobacteria, can produce lichens that are very different in most properties, meeting non-DNA criteria for being different "species". Historically, these different combinations were classified as different species. When the fungus is identified as being the same using modern DNA methods, these apparently different species get reclassified as the same species under the current (2014) convention for classification by fungal component. This has led to debate about this classification convention. These apparently different "species" have their own independent evolutionary history.
There is also debate as to the appropriateness of giving the same binomial name to the fungus, and to the lichen that combines that fungus with an alga or cyanobacterium (synecdoche). This is especially the case when combining the same fungus with different algae or cyanobacteria produces dramatically different lichen organisms, which would be considered different species by any measure other than the DNA of the fungal component. If the whole lichen produced by the same fungus growing in association with different algae or cyanobacteria, were to be classified as different "species", the number of "lichen species" would be greater. | 1 | Applied and Interdisciplinary Chemistry |
The potential of using cell microencapsulation in successful clinical applications can be realized only if several requirements encountered during the development process are optimized such as the use of an appropriate biocompatible polymer to form the mechanically and chemically stable semi-permeable matrix, production of uniformly sized microcapsules, use of an appropriate immune-compatible polycations cross-linked to the encapsulation polymer to stabilized the capsules, selection of a suitable cell type depending on the situation. | 1 | Applied and Interdisciplinary Chemistry |
Hydrogen was initially thought to be toxic based on experiments by Lavoisier, however, the purity of the hydrogen was taken into question when later experiments discovered hydrogen to effectively treat measles in the 1790s.
* factitious air (Boyle)
* hydrogene – means "water former" from hydro- and gene-
* inflammable air
* inflammable gas
* base of inflammable air
*zincic inflammable air
*martial inflammable air | 1 | Applied and Interdisciplinary Chemistry |
The following are synthetic gemstones that were developed by Tairus scientists; they are alternately referred to as Tairus stones (e.g. "Tairus Ruby").
*Floating zone ruby, synthesized in 1991 (no longer in production)
*Hydrothermal ruby, synthesized in 1992 by Alexander Dokukin.
*Hydrothermal aquamarine, synthesized in 1993.
*Hydrothermal sapphires, in pink, green, orange, and blue.
*Colombian color emerald, developed in 2004. | 0 | Theoretical and Fundamental Chemistry |
The advent of inexpensive microarray experiments created several specific bioinformatics challenges: the multiple levels of replication in experimental design (Experimental design); the number of platforms and independent groups and data format (Standardization); the statistical treatment of the data (Data analysis); mapping each probe to the mRNA transcript that it measures (Annotation); the sheer volume of data and the ability to share it (Data warehousing). | 1 | Applied and Interdisciplinary Chemistry |
The bond dipole moment uses the idea of electric dipole moment to measure the polarity of a chemical bond within a molecule. It occurs whenever there is a separation of positive and negative charges.
The bond dipole μ is given by:
The bond dipole is modeled as δ — δ with a distance d between the partial charges δ and δ. It is a vector, parallel to the bond axis, pointing from minus to plus, as is conventional for electric dipole moment vectors.
Chemists often draw the vector pointing from plus to minus. This vector can be physically interpreted as the movement undergone by electrons when the two atoms are placed a distance d apart and allowed to interact, the electrons will move from their free state positions to be localised more around the more electronegative atom.
The SI unit for electric dipole moment is the coulomb–meter. This is too large to be practical on the molecular scale.
Bond dipole moments are commonly measured in debyes, represented by the symbol D, which is obtained by measuring the charge in units of 10 statcoulomb and the distance d in Angstroms. Based on the conversion factor of
10 statcoulomb being 0.208 units of elementary charge, so 1.0 debye results from an electron and a proton separated by 0.208 Å. A useful conversion factor is 1 D = 3.335 64 C m.
For diatomic molecules there is only one (single or multiple) bond so the bond dipole moment is the molecular dipole moment, with typical values in the range of 0 to 11 D. At one extreme, a symmetrical molecule such as chlorine, , has zero dipole moment, while near the other extreme, gas phase potassium bromide, KBr, which is highly ionic, has a dipole moment of 10.41 D.
For polyatomic molecules, there is more than one bond. The total molecular dipole moment may be approximated as the vector sum of the individual bond dipole moments. Often bond dipoles are obtained by the reverse process: a known total dipole of a molecule can be decomposed into bond dipoles. This is done to transfer bond dipole moments to molecules that have the same bonds, but for which the total dipole moment is not yet known. The vector sum of the transferred bond dipoles gives an estimate for the total (unknown) dipole of the molecule. | 0 | Theoretical and Fundamental Chemistry |
In foods, stabilizers prevent spoilage. Classes of food stabilizers include emulsifiers, thickeners and gelling agents, foam stabilizers, humectants, anticaking agents, and coating agents. | 0 | Theoretical and Fundamental Chemistry |
Pipefitters should not be confused with pipelayers. Both trades involve pipe and valves and both use some of the same tools. However, pipelayers usually work outside, laying pipe underground or on the seabed, whereas pipefitters typically work inside, installing piping in buildings, aeroplanes, or ships. One author summarizes the different tasks this way:
<blockquote><poem>Pipe layers operate the backhoes and trenching machinery that dig the trenches to accommodate the placement of sanitary sewer pipes and stormwater sewer drainpipes. They use surveyor’s equipment to ensure the trenches have the proper slope and install the pieces of pipe in the trenches, joining the ends with cement, glue, or welding equipment. Using an always-open or always-closed valve called a tap, pipe layers connect them to a wider system and bury the pipes.
Pipe fitters plan and test piping and tubing layouts; cut, bend or fabricate pipe or tubing segments; and join those segments by threading them, using lead joints, welding, brazing, cementing, or soldering them together. They install manual, pneumatic, hydraulic and electric valves in pipes to control the flow through the pipes or tubes. These workers create the system of tubes in boilers and make holes in walls and bulkheads to accommodate the passage of the pipes they install. | 1 | Applied and Interdisciplinary Chemistry |
1) [https://www.springer.com/chemistry/electrochemistry/book/978-0-387-28429-3 N4 Macrocyclic Metal Complexes]. J.H. ZAGAL, F. Bedioui, J.P. Dodelet (Eds), Springer New York ( 2006).
* [http://editorial.usach.cl/content/electroqu%C3%ADmica-voltametr%C3%ADas-sobre-electrodo-s%C3%B3lido Electroquímica: voltametrías sobre electrodo sólido]. Fethi Bedioui, Silvia Gutiérrez Granados, Alejandro Alatorre Ordaz y 2) J.H. ZAGAL, Sello Editorial Usach, (2009).
3https://www.springer.com/la/book/9783319311708) “Electrochemistry of MN4 macrocyclic metal complexes” Volume 1 Energy: “Electrochemistry of MN4 Macrocyclic complexes” J.H. Zagal, F. Bedioui (Eds) Springer Switzerland (2016) (segunda edición) 316 páginas.
4) https://www.springer.com/gb/book/9783319313306 “Electrochemistry of MN4 macrocyclic metal complexes” Volume 2 Biomimesis, Electroanalysis, and Electrosynthesis of MN4 complexes” J.H. Zagal, F. Bedioui, (Eds) Springer Switzerland (2016) (segunda edición) 436 páginas | 0 | Theoretical and Fundamental Chemistry |
In the assembly of integrated circuit packages to printed circuit boards, a head-in-pillow defect (HIP or HNP), also called ball-and-socket, is a failure of the soldering process. For example, in the case of a ball grid array (BGA) package, the pre-deposited solder ball on the package and the solder paste applied to the circuit board may both melt, but the melted solder does not join. A cross-section through the failed joint shows a distinct boundary between the solder ball on the part and the solder paste on the circuit board, rather like a section through a head resting on a pillow.
The defect can be caused by surface oxidation or poor wetting of the solder, or by distortion of the integrated circuit package or circuit board by the heat of the soldering process. This is particularly a concern when using lead-free solder, which requires higher processing temperature.
The defect can be attributed to a chain of events during soldering. Initially, the ball is in contact with solder paste. During heating, the board and components undergo thermal expansion, can flex, and some of the balls can be lifted off the paste. Oxidation occurs rapidly at elevated temperature, and when the surfaces come in contact again, the residual flux activity may not be sufficient to disrupt the oxide layer. The solder paste composition, eg. flux with higher activation temperature, together with the wetting characteristics of the solder ball, are the most significant mitigation factors.
Since the warping of the circuit board or integrated circuit may disappear when the board cools, an intermittent fault may be created. Diagnosis of head-in-pillow defects may require use of X-rays or EOTPR (Electro Optical Terahertz Pulse Reflectometry), since the solder joints are hidden between the integrated circuit package and the printed circuit board. | 1 | Applied and Interdisciplinary Chemistry |
In electrochemistry, the Randles–Ševčík equation describes the effect of scan rate on the peak current for a cyclic voltammetry experiment. For simple redox events such as the ferrocene/ferrocenium couple, depends not only on the concentration and diffusional properties of the electroactive species but also on scan rate.
Or if the solution is at 25 °C:
* = current maximum in amps
* = number of electrons transferred in the redox event (usually 1)
* = electrode area in cm
* = Faraday constant in C mol
* = diffusion coefficient in cm/s
* = concentration in mol/cm
* = scan rate in V/s
* = Gas constant in J K mol
* = temperature in K
* The constant with a value of 2.69x10 has units of C mol V
For novices in electrochemistry, the predictions of this equation appear counter-intuitive, i.e. that increases at faster voltage scan rates. It is important to remember that current, i, is charge (or electrons passed) per unit time. In cyclic voltammetry, the current passing through the electrode is limited by the diffusion of species to the electrode surface. This diffusion flux is influenced by the concentration gradient near the electrode. The concentration gradient, in turn, is affected by the concentration of species at the electrode, and how fast the species can diffuse through solution. By changing the cell voltage, the concentration of the species at the electrode surface is also changed, as set by the Nernst equation. Therefore, a faster voltage sweep causes a larger concentration gradient near the electrode, resulting in a higher current. | 0 | Theoretical and Fundamental Chemistry |
In medicine, actinic effects are generally described in terms of the dermis or outer layers of the body, such as eyes (see: Actinic conjunctivitis) and upper tissues that the sun would normally affect, rather than deeper tissues that higher-energy shorter-wavelength radiation such as x-ray and gamma might affect. Actinic is also used to describe medical conditions that are triggered by exposure to light, especially UV light (see actinic keratosis).
The term actinic rays is used to refer to this phenomenon. | 0 | Theoretical and Fundamental Chemistry |
Since at least the mid-2000s, there has been intensifying interest in developing short interfering RNAs for biomedical and therapeutic applications. Bolstering this interest is a growing number of experiments which have successfully demonstrated the clinical potential and safety of small RNAs for combatting diseases ranging from viral infections to cancer as well as neurodegenerative disorders. In 2004, the first Investigational New Drug applications for siRNA were filed in the United States with the Food and Drug Administration; it was intended as a therapy for age-related macular degeneration. RNA silencing in vitro and in vivo has been accomplished by creating triggers (nucleic acids that induce RNAi) either via expression in viruses or synthesis of oligonucleotides. Optimistically many studies indicate that small RNA-based therapies may offer novel and potent weapons against pathogens and diseases where small molecule/pharmacologic and vaccine/biologic treatments have failed or proved less effective in the past. However, it is also warned that the design and delivery of small RNA effector molecules should be carefully considered in order to ensure safety and efficacy.
The role of RNA silencing in therapeutics, clinical medicine, and diagnostics is a fast developing area and it is expected that in the next few years some of the compounds using this technology will reach market approval. A report has been summarized below to highlight the many clinical domains in which RNA silencing is playing an increasingly important role, chief among them are ocular and retinal disorders, cancer, kidney disorders, LDL lowering, and antiviral. The following table displays a listing of RNAi based therapy currently in various phases of clinical trials. The status of these trials can be monitored on the ClinicalTrials.gov website, a service of the National Institutes of Health (NIH). Of note are treatments in development for ocular and retinal disorders, that were among the first compounds to reach clinical development. AGN211745 (sirna027) (Allergan) and bevasiranib (Cand5) (Opko) underwent clinical development for the treatment of age-related macular degeneration, but trials were terminated before the compounds reached the market. Other compounds in development for ocular conditions include SYL040012 (Sylentis) and QPI-007 (Quark). SYL040012 (bamosinan) is a drug candidate under clinical development for glaucoma, a progressive optic neurdegeneration frequently associated to increased intraocular pressure; QPI-007 is a candidate for the treatment of angle-closure glaucoma and Non-arteritic anterior ischaemic optic neuropathy; both compounds are currently undergoing phase II clinical trials. Several compounds are also under development for conditions such as cancer and rare diseases. | 1 | Applied and Interdisciplinary Chemistry |
Tests have shown some toxins near blooms can be in the air and thereby be inhaled, which could affect health. | 0 | Theoretical and Fundamental Chemistry |
Users can design a rAAV vector to any target genomic locus and perform both gross and subtle endogenous gene alterations in mammalian somatic cell-types. These include gene knock-outs for functional genomics, or the ‘knock-in’ of protein tag insertions to track translocation events at physiological levels in live cells. Most importantly, rAAV targets a single allele at a time and does not result in any off-target genomic alterations. Because of this, it is able to routinely and accurately model genetic diseases caused by subtle SNPs or point mutations that are increasingly the targets of novel drug discovery programs. | 1 | Applied and Interdisciplinary Chemistry |
* Blueprint reading
* Detailing
* CAD drawing coordinators
* Layout
* Pipe threading
* Pipe grinding
* Plasma cutting
* Gas arc cutting
* Rigging
* Brazing
* Soldering
* Mitering
* Tube bending
* Valve installation and repair
* Mechanical pipe cutting and grooving
* Supports and hanger installation
* Preparation and installation of medical gas piping
* Welding; GMAW, TiG, SMAW, Orbital) | 1 | Applied and Interdisciplinary Chemistry |
In fluid thermodynamics, a heat transfer fluid is a gas or liquid that takes part in heat transfer by serving as an intermediary in cooling on one side of a process, transporting and storing thermal energy, and heating on another side of a process. Heat transfer fluids are used in countless applications and industrial processes requiring heating or cooling, typically in a closed circuit and in continuous cycles. Cooling water, for instance, cools an engine, while heating water in a hydronic heating system heats the radiator in a room.
Water is the most common heat transfer fluid because of its economy, high heat capacity and favorable transport properties. However, the useful temperature range is restricted by freezing below 0 °C and boiling at elevated temperatures depending on the system pressure. Antifreeze additives can alleviate the freezing problem to some extent. However, many other heat transfer fluids have been developed and used in a huge variety of applications. For higher temperatures, oil or synthetic hydrocarbon- or silicone-based fluids offer lower vapor pressure. Molten salts and molten metals can be used for transferring and storing heat at temperatures above 300 to 400 °C where organic fluids start to decompose. Gases such as water vapor, nitrogen, argon, helium and hydrogen have been used as heat transfer fluids where liquids are not suitable. For gases the pressure typically needs to be elevated to facilitate higher flow rates with low pumping power.
In order to prevent overheating, fluid flows inside a system or a device so as to transfer the heat outside that particular device or system.
They generally have a high boiling point and a high heat capacity. High boiling point prevents the heat transfer liquids from vaporising at high temperatures. High heat capacity enables a small amount of the refrigerant to transfer a large amount of heat very efficiently.
It must be ensured that the heat transfer liquids used should not have a low boiling point. This is because a low boiling point will result in vaporisation of the liquid at low temperatures when they are used to exchange heat with hot substances. This will produce vapors of the liquid in the machine itself where they are used.
Also, the heat transfer fluids should have high heat capacity. The heat capacity denotes the amount of heat the fluid can hold without changing its temperature. In case of liquids, it also shows the amount of heat the liquid can hold before its temperature reaches its boiling point and ultimately vaporises.
If the fluid has low heat capacity, then it will mean that a large amount of the fluid will be required to exchange a relatively small amount of heat. This will increase the cost of using heat transfer fluids and will reduce the efficiency of the process.
In case of liquid heat transfer fluids, usage of their small quantity will result in their vaporisation which can be dangerous for the equipment where they are used. The equipment will be designed for liquids but their vaporisation will include vapors in the flow channel. Also gases occupy larger volume than liquids at the same pressure. The production of vapors will increase the pressure on the walls of the pipe/channel where it will be flowing. This may cause the flow channel to rupture. | 1 | Applied and Interdisciplinary Chemistry |
In one variation of the Reformatsky reaction an iodolactam is coupled with an aldehyde with triethylborane in toluene at -78 °C. | 0 | Theoretical and Fundamental Chemistry |
Because a large portion of the pairs of a and b contain zeros in one or both conditions, they are impossible to plot as-is on a log scale. Other MA plotting functions artificially include these condition-unique points in the plot by spreading them vertically as a "smear" on the left or horizontally as a "[https://web.archive.org/web/20110825045150/http://projetos.inpa.gov.br/i3geo/pacotes/r/win/library/graphics/html/rug.html rug]" at the very top and bottom of the plot. In an RA plot, by contrast, the uniques are included via addition a small epsilon factor (between .1 and .5) which places them in a more statistically appropriate location in the plot. | 1 | Applied and Interdisciplinary Chemistry |
A Soxhlet extractor has three main sections: a percolator (boiler and reflux) which circulates the solvent, a thimble (usually made of thick filter paper) which retains the solid to be extracted, and a siphon mechanism, which periodically empties the condensed solvent from the thimble back into the percolator. | 0 | Theoretical and Fundamental Chemistry |
Aliphatic nitro compounds can be synthesized by various methods; notable examples include:
*Free radical nitration of alkanes. The reaction produces fragments from the parent alkane, creating a diverse mixture of products; for instance, nitromethane, nitroethane, 1-nitropropane, and 2-nitropropane are produced by treating propane with nitric acid in the gas phase (e.g. 350–450 °C and 8–12 atm).
*Nucleophilic substitution reactions between halocarbons or organosulfates with silver or alkali nitrite salts.
*Nitromethane can be produced in the laboratory by treating sodium chloroacetate with sodium nitrite.
*Oxidation of oximes or primary amines.
*Reduction of β-nitro alcohols or nitroalkenes.
*By decarboxylation of α-nitro carboxylic acids formed from nitriles and ethyl nitrate. | 0 | Theoretical and Fundamental Chemistry |
Chromosome jumping library is different from chromosome walking due to the manipulations executed before the cloning step. In order to construct the library of chromosome jumping, individual clones originate from random points in the genome (general jumping libraries first basic protocol) or from the termini of specific restriction fragments (specific jumping libraries alternate protocol) should be identified. | 1 | Applied and Interdisciplinary Chemistry |
Known implementations of the hydrothermal HCl regeneration processes include the PORI process (1974 for J&L Steel, dismantled) and the optimized SMS Demag wet process (2008 for ThyssenKrupp Steel, under construction). | 0 | Theoretical and Fundamental Chemistry |
If the lone pairs of electrons on the oxygens at the anomeric center of 2-methoxypyran are shown, then a brief examination of the conformations of the anomers reveal that the β-anomer always has at least one pair of eclipsing (coplanar 1,3-interacting) lone pairs, this n-n repulsion is a high energy situation. On the other hand, the α-anomer has conformations in which there are no n-n repulsions, and that is true in the exo-anomeric conformation. The energetically unfavourable n-n repulsion present in the β-anomer, coupled with the energetically favourable hydrogen bond between the axial H-5 and a lone pair of electrons on the axial α-anomeric substituent (C-H/n hydrogen bond), have been suggested [references 7 and 8] to account for most of the energetic difference between the anomers, the anomeric effect. The molecular mechanics program StruMM3D, which is not specially parameterized for the anomeric effect, estimates that the dipolar contributions to the anomeric effect (primarily the n-n repulsion, and C-H hydrogen bonding discussed above) are about 1.5 kcal/mol. | 0 | Theoretical and Fundamental Chemistry |
The mitochondrial intermembrane space is the space between the outer membrane and the inner membrane. It is also known as perimitochondrial space. Because the outer membrane is freely permeable to small molecules, the concentrations of small molecules, such as ions and sugars, in the intermembrane space is the same as in the cytosol. However, large proteins must have a specific signaling sequence to be transported across the outer membrane, so the protein composition of this space is different from the protein composition of the cytosol. One protein that is localized to the intermembrane space in this way is cytochrome c. | 1 | Applied and Interdisciplinary Chemistry |
In hydrothermal liquefaction processes, long carbon chain molecules in biomass are thermally cracked and oxygen is removed in the form of HO (dehydration) and CO (decarboxylation). These reactions result in the production of high H/C ratio bio-oil. Simplified descriptions of dehydration and decarboxylation reactions can be found in the literature (e.g. Asghari and Yoshida (2006) and Snåre et al. (2007). | 0 | Theoretical and Fundamental Chemistry |
Many inhibitors of glycosyltransferases are known. Some of these are natural products, such as moenomycin, an inhibitor of peptidoglycan glycosyltransferases, the nikkomycins, inhibitors of chitin synthase, and the echinocandins, inhibitors of fungal β-1,3-glucan synthases. Some glycosyltransferase inhibitors are of use as drugs or antibiotics. Moenomycin is used in animal feed as a growth promoter. Caspofungin has been developed from the echinocandins and is in use as an antifungal agent. Ethambutol is an inhibitor of mycobacterial arabinotransferases and is used for the treatment of tuberculosis. Lufenuron is an inhibitor of insect chitin syntheses and is used to control fleas in animals. Imidazolium-based synthetic inhibitors of glycosyltransferases have been designed for use as antimicrobial and antiseptic agents. | 0 | Theoretical and Fundamental Chemistry |
Each candidate CRM (cCRM) is cloned upstream of a reporter gene. Compared to traditional reporter assays, the main innovation is the use of fluorescence activated cell sorting (FACS) of dissociated cells, instead of microscopy, to screen for tissue-specific enhancers. This approach utilizes a two-marker system: in each embryo, one marker (here, the rat CD2 cell surface protein) is used to label cells of a specific tissue for being sorted by FACS, and the other marker (here, green fluorescent protein GFP) is used as a reporter of CRM activity.
Cells are sorted according to their tissue type and then by GFP fluorescence, and the cCRMs are recovered by PCR from double-positive sorted cells, and from total input cells. High-throughput sequencing of both populations then allows measuring the relative abundance of each cCRM in input and sorted populations; one can then assess the enrichment or depletion of each cCRM in double-positive cells versus input as a measure of activity in the CD2-positive cell type being tested. | 1 | Applied and Interdisciplinary Chemistry |
This section summarizes the coefficients for some common materials.
For isotropic materials the coefficients linear thermal expansion α and volumetric thermal expansion α are related by .
For liquids usually the coefficient of volumetric expansion is listed and linear expansion is calculated here for comparison.
For common materials like many metals and compounds, the thermal expansion coefficient is inversely proportional to the melting point.
In particular, for metals the relation is:
for halides and oxides
In the table below, the range for α is from 10 K for hard solids to 10 K for organic liquids. The coefficient α varies with the temperature and some materials have a very high variation; see for example the variation vs. temperature of the volumetric coefficient for a semicrystalline polypropylene (PP) at different pressure, and the variation of the linear coefficient vs. temperature for some steel grades (from bottom to top: ferritic stainless steel, martensitic stainless steel, carbon steel, duplex stainless steel, austenitic steel). The highest linear coefficient in a solid has been reported for a Ti-Nb alloy.
(The formula is usually used for solids.) | 0 | Theoretical and Fundamental Chemistry |
A typical reaction with dissolution involves a weak base, B, dissolving in an acidic aqueous solution.
This reaction is very important for pharmaceutical products. Dissolution of weak acids in alkaline media is similarly important.
The uncharged molecule usually has lower solubility than the ionic form, so solubility depends on pH and the acid dissociation constant of the solute. The term "intrinsic solubility" is used to describe the solubility of the un-ionized form in the absence of acid or alkali.
Leaching of aluminium salts from rocks and soil by acid rain is another example of dissolution with reaction: alumino-silicates are bases which react with the acid to form soluble species, such as Al(aq).
Formation of a chemical complex may also change solubility. A well-known example is the addition of a concentrated solution of ammonia to a suspension of silver chloride, in which dissolution is favoured by the formation of an ammine complex.
When sufficient ammonia is added to a suspension of silver chloride, the solid dissolves. The addition of water softeners to washing powders to inhibit the formation of soap scum provides an example of practical importance. | 0 | Theoretical and Fundamental Chemistry |
Metal ions and metallic compounds are often used in medical treatments and diagnoses. Compounds containing metal ions can be used as medicine, such as lithium compounds and auranofin. Metal compounds and ions can also produce harmful effects on the body due to the toxicity of several types of metals. For example, arsenic works as a potent poison due to its effects as an enzyme inhibitor, disrupting ATP production. | 1 | Applied and Interdisciplinary Chemistry |
LaNi is an intermetallic compound with a CaCu structure. It belongs to the hexagonal crystal system. It can be oxidized by air above 200 °C, and react with hydrochloric acid, sulfuric acid or nitric acid above 20 °C. LaNi can be used as a catalyst for hydrogenation reactions. | 1 | Applied and Interdisciplinary Chemistry |
Many catabolic biochemical processes, such as glycolysis, the citric acid cycle, and beta oxidation, produce the reduced coenzyme NADH. This coenzyme contains electrons that have a high transfer potential; in other words, they will release a large amount of energy upon oxidation. However, the cell does not release this energy all at once, as this would be an uncontrollable reaction. Instead, the electrons are removed from NADH and passed to oxygen through a series of enzymes that each release a small amount of the energy. This set of enzymes, consisting of complexes I through IV, is called the electron transport chain and is found in the inner membrane of the mitochondrion. Succinate is also oxidized by the electron transport chain, but feeds into the pathway at a different point.
In eukaryotes, the enzymes in this electron transport system use the energy released from O by NADH to pump protons across the inner membrane of the mitochondrion. This causes protons to build up in the intermembrane space, and generates an electrochemical gradient across the membrane. The energy stored in this potential is then used by ATP synthase to produce ATP. Oxidative phosphorylation in the eukaryotic mitochondrion is the best-understood example of this process. The mitochondrion is present in almost all eukaryotes, with the exception of anaerobic protozoa such as Trichomonas vaginalis that instead reduce protons to hydrogen in a remnant mitochondrion called a hydrogenosome. | 1 | Applied and Interdisciplinary Chemistry |
A magnesium(I) dimer is a molecular compound containing a magnesium to magnesium bond (Mg-Mg), giving the metal an apparent +1 oxidation state.
Alkaline earth metals are commonly found in the +2-oxidation state, such as magnesium. The M are considered as redox-inert, meaning that the +2 state is significant. However, recent advancements in main group chemistry have yielded low-valent magnesium(I) dimers, also given as Mg(I), with the first compound being reported in 2007. They can be generally represented as LMg-MgL, with L being a monoanionic ligand. For example, β-diketiminate, commonly referred to as Nacnac, is a useful chelate regarding these complexes. By tuning the ligand, the thermodynamics of the complex change. For instance, the ability to add substituents onto Nacnac can contribute to the steric bulk, which can affect reactivity and stability. As their discovery has grown, so has their usefulness. They are employed in organic and inorganic reduction reactions. It is soluble in a hydrocarbon solvent, like toluene, stoichiometric, selective, and safe. | 0 | Theoretical and Fundamental Chemistry |
A crystal net is an infinite molecular model of a crystal. Similar models existed in Antiquity, notably the atomic theory associated with Democritus, which was criticized by Aristotle because such a theory entails a vacuum, which Aristotle believed nature abhors. Modern atomic theory traces back to Johannes Kepler and his work on geometric packing problems. Until the twentieth century, graph-like models of crystals focused on the positions of the (atomic) components, and these pre-20th century models were the focus of two controversies in chemistry and materials science.
The two controversies were (1) the controversy over Robert Boyle’s corpuscular theory of matter, which held that all material substances were composed of particles, and (2) the controversy over whether crystals were minerals or some kind of vegetative phenomenon. During the eighteenth century, Kepler, Nicolas Steno, René Just Haüy, and others gradually associated the packing of Boyle-type corpuscular units into arrays with the apparent emergence of polyhedral structures resembling crystals as a result. During the nineteenth century, there was considerably more work done on polyhedra and also of crystal structure, notably in the derivation of the Crystallographic groups based on the assumption that a crystal could be regarded as a regular array of unit cells. During the early twentieth century, the physics and chemistry community largely accepted Boyle's corpuscular theory of matter—by now called the atomic theory—and X-ray crystallography was used to determine the position of the atomic or molecular components within the unit cells (by the early twentieth century, unit cells were regarded as physically meaningful).
However, despite the growing use of stick-and-ball molecular models, the use of graphical edges or line segments to represent chemical bonds in specific crystals have become popular more recently, and the publication of encouraged efforts to determine graphical structures of known crystals, to generate crystal nets of as yet unknown crystals, and to synthesize crystals of these novel crystal nets. The coincident expansion of interest in tilings and tessellations, especially those modeling quasicrystals, and the development of modern Nanotechnology, all facilitated by the dramatic increase in computational power, enabled the development of algorithms from computational geometry for the construction and analysis of crystal nets. Meanwhile, the ancient association between models of crystals and tessellations has expanded with Algebraic topology. There is also a thread of interest in the very-large-scale integration (VLSI) community for using these crystal nets as circuit designs. | 0 | Theoretical and Fundamental Chemistry |
GIS in environmental contamination is the use of GIS software in mapping out the contaminants in soil and water using the spatial interpolation tools from GIS. Spatial interpolation allows for more efficient approach to remediation and monitoring of soil and water contaminants. Soil and water contamination by metals and other contaminants have become a major environmental problem after the industrialization across many parts of the world. As a result, environmental agencies are placed in charge in remediating, monitoring, and mitigating the soil contamination sites. GIS is used to monitor the sites for metal contaminants in the soil, and based on the GIS analysis, highest risk sites are identified in which majority of the remediation and monitoring takes place. | 1 | Applied and Interdisciplinary Chemistry |
Each class of product may undergo different types of preclinical research. For instance, drugs may undergo pharmacodynamics (what the drug does to the body) (PD), pharmacokinetics (what the body does to the drug) (PK), ADME, and toxicology testing. This data allows researchers to allometrically estimate a safe starting dose of the drug for clinical trials in humans. Medical devices that do not have drug attached will not undergo these additional tests and may go directly to good laboratory practices (GLP) testing for safety of the device and its components. Some medical devices will also undergo biocompatibility testing which helps to show whether a component of the device or all components are sustainable in a living model. Most preclinical studies must adhere to GLPs in ICH Guidelines to be acceptable for submission to regulatory agencies such as the Food & Drug Administration in the United States.
Typically, both in vitro and in vivo tests will be performed. Studies of drug toxicity include which organs are targeted by that drug, as well as if there are any long-term carcinogenic effects or toxic effects causing illness. | 1 | Applied and Interdisciplinary Chemistry |
Viktor Trkal considered the Beltrami flows without any external forces in 1919 for the scalar function , i.e.,
Introduce the following separation of variables
then the equation satisfied by becomes
The Chandrasekhar–Kendall functions satisfy this equation. | 1 | Applied and Interdisciplinary Chemistry |
Coherent anti-Stokes Raman spectroscopy (CARS) is a non-
linear process in which the energy difference of a pair of incoming photons
matches the energy of the vibrational mode of a molecular bond of interest.
This phonon population is coherently probed by a third photon and anti-
Stokes radiation is emitted. | 0 | Theoretical and Fundamental Chemistry |
Well-known acyl compounds are the acyl chlorides, such as acetyl chloride (CHCOCl) and benzoyl chloride (CHCOCl). These compounds, which are treated as sources of acylium cations, are good reagents for attaching acyl groups to various substrates. Amides (RC(O)NR′) and esters (RC(O)OR′) are classes of acyl compounds, as are ketones (RC(O)R′) and aldehydes (RC(O)H), where R and R′ stand for organyl (or hydrogen in the case of formyl). | 0 | Theoretical and Fundamental Chemistry |
Mechanical spalling occurs at high-stress contact points, for example, in a ball bearing. Spalling occurs in preference to brinelling, where the maximal shear stress occurs not at the surface, but just below, shearing the spall off.
One of the simplest forms of mechanical spalling is plate impact, in which two waves of compression are reflected on the free-surfaces of the plates and then interact to generate a region of high tensile stress inside one of the plates.
Spalling can also occur as an effect of cavitation, where fluids are subjected to localized low pressures that cause vapour bubbles to form, typically in pumps, water turbines, vessel propellers, and even piping under some conditions. When such bubbles collapse, a localized high pressure can cause spalling on adjacent surfaces. | 1 | Applied and Interdisciplinary Chemistry |
Ordinarily, Miller indices are always integers by definition, and this constraint is physically significant. To understand this, suppose that we allow a plane (abc) where the Miller "indices" a, b and c (defined as above) are not necessarily integers.
If a, b and c have rational ratios, then the same family of planes can be written in terms of integer indices (hkℓ) by scaling a, b and c appropriately: divide by the largest of the three numbers, and then multiply by the least common denominator. Thus, integer Miller indices implicitly include indices with all rational ratios. The reason why planes where the components (in the reciprocal-lattice basis) have rational ratios are of special interest is that these are the lattice planes: they are the only planes whose intersections with the crystal are 2d-periodic.
For a plane (abc) where a, b and c have irrational ratios, on the other hand, the intersection of the plane with the crystal is not periodic. It forms an aperiodic pattern known as a quasicrystal. This construction corresponds precisely to the standard "cut-and-project" method of defining a quasicrystal, using a plane with irrational-ratio Miller indices. (Although many quasicrystals, such as the Penrose tiling, are formed by "cuts" of periodic lattices in more than three dimensions, involving the intersection of more than one such hyperplane.) | 0 | Theoretical and Fundamental Chemistry |
Life consists of reproduction with (heritable) variations. NASA defines life as "a self-sustaining chemical system capable of [[evolution|Darwinian [i.e., biological] evolution]]." Such a system is complex; the last universal common ancestor (LUCA), presumably a single-celled organism which lived some 4 billion years ago, already had hundreds of genes encoded in the DNA genetic code that is universal today. That in turn implies a suite of cellular machinery including messenger RNA, transfer RNA, and ribosomes to translate the code into proteins. Those proteins included enzymes to operate its anaerobic respiration via the Wood–Ljungdahl metabolic pathway, and a DNA polymerase to replicate its genetic material.
The challenge for abiogenesis (origin of life) researchers is to explain how such a complex and tightly interlinked system could develop by evolutionary steps, as at first sight all its parts are necessary to enable it to function. For example, a cell, whether the LUCA or in a modern organism, copies its DNA with the DNA polymerase enzyme, which is in turn produced by translating the DNA polymerase gene in the DNA. Neither the enzyme nor the DNA can be produced without the other. The evolutionary process could have involved molecular self-replication, self-assembly such as of cell membranes, and autocatalysis. Nonetheless, the transition of non-life to life has never been observed experimentally.
The precursors to the development of a living cell like the LUCA are clear enough, if disputed in their details: a habitable world is formed with a supply of minerals and liquid water. Prebiotic synthesis creates a range of simple organic compounds, which are assembled into polymers such as proteins and RNA. The process after the LUCA, too, is readily understood: biological evolution caused the development of a wide range of species with varied forms and biochemical capabilities. The derivation of living things such as the LUCA from simple components, however, is far from understood.
Although Earth remains the only place where life is known, the science of astrobiology seeks evidence of life on other planets. The 2015 NASA strategy on the origin of life aimed to solve the puzzle by identifying interactions, intermediary structures and functions, energy sources, and environmental factors that contributed to the diversity, selection, and replication of evolvable macromolecular systems, and mapping the chemical landscape of potential primordial informational polymers. The advent of polymers that could replicate, store genetic information, and exhibit properties subject to selection was, it suggested, most likely a critical step in the emergence of prebiotic chemical evolution. Those polymers derived, in turn, from simple organic compounds such as nucleobases, amino acids, and sugars that could have been formed by reactions in the environment. A successful theory of the origin of life must explain how all these chemicals came into being. | 0 | Theoretical and Fundamental Chemistry |
Sala was appointed as a personal physician of Count Anton Günther of Oldenburg who also appointed Sala as supervisor of the pharmacy system in the state of Oldenburg. In 1620 Sala went to Hamburg as a medical chemist. In June of that year, he became a personal physician of Count Ernst von Holstein-Schaumburg. In 1622, Maurice, Landgrave of Hesse-Kassel called him to Kassel and may also have recommended Sala to his son-in-law, Duke John Albert II, Duke of Mecklenburg, to whom Sala has served as a personal physician from about 1623. In any case, he installed Sala in Güstrow in 1625 to live and work in the castle.
At the end of May 1628, Sala accompanied Duke Johann Albrecht II, expelled by Wallenstein, into exile in Bernburg in Anhalt. On 26 June 1628 FürstLudwig I of Anhalt-Köthen admitted by him to the Fruchtbringende Gesellschaft at the same time as Johann Albrecht II and Otto von Preen. The prince gave Sala the title "der Lindernde" ("the soothing") and the motto "die Schmerzen“ ("pain"). Sala took the chamomile blossom as his emblem. Salas entry can be found at #160 in the Köthener Gesellschaftsbuch'.
In the summer of 1629, Sala accompanied his duke into exile in Lübeck. There he remained as a personal physician until the death of the Duke in 1636, then served his son, Duke Gustav Adolf of Mecklenburg-Güstrow, in the same position. | 1 | Applied and Interdisciplinary Chemistry |
The Codon Adaptation Index (CAI) is the most widespread technique for analyzing codon usage bias. As opposed to other measures of codon usage bias, such as the effective number of codons (Nc), which measure deviation from a uniform bias (null hypothesis), CAI measures the deviation of a given protein coding gene sequence with respect to a reference set of genes. CAI is used as a quantitative method of predicting the level of expression of a gene based on its codon sequence. | 1 | Applied and Interdisciplinary Chemistry |
Alternative U-to-C mRNA editing was first reported in WT1 (Wilms Tumor-1) transcripts, and non-classic G-A mRNA changes were first observed in HNRNPK (heterogeneous nuclear ribonucleoprotein K) transcripts in both malignant and normal colorectal samples. The latter changes were also later seen alongside non-classic U-to-C alterations in brain cell TPH2 (tryptophan hydroxylase 2) transcripts. Although the reverse amination might be the simplest explanation for U-to-C changes, transamination and transglycosylation mechanisms have been proposed for plant U-to-C editing events in mitochondrial transcripts. A recent study reported novel G-to-A mRNA changes in WT1 transcripts at two hotspots, proposing the APOBEC3A (apolipoprotein B mRNA editing enzyme, catalytic polypeptide 3A) as the enzyme implicated in this class of alternative mRNA editing. It was also shown that alternative mRNA changes were associated with canonical WT1 splicing variants, indicating their functional significance. | 1 | Applied and Interdisciplinary Chemistry |
A single viscosity measurement at a constant speed in a typical viscometer is a measurement of the instrument viscosity of a fluid (not the apparent viscosity). In the case of non-Newtonian fluids, measurement of apparent viscosity without knowledge of the shear rate is of limited value: the measurement cannot be compared to other measurements if the speed and geometry of the two instruments is not identical. An apparent viscosity that is reported without the shear rate or information about the instrument and settings (e.g. speed and spindle type for a rotational viscometer) is meaningless.
Multiple measurements of apparent viscosity at different, well-defined shear rates, can give useful information about the non-Newtonian behaviour of a fluid, and allow it to be modeled. | 1 | Applied and Interdisciplinary Chemistry |
An agrochemical or agrichemical, a contraction of agricultural chemical, is a chemical product used in industrial agriculture. Agrichemical refers to biocides (pesticides including insecticides, herbicides, fungicides and nematicides) and synthetic fertilizers. It may also include hormones and other chemical growth agents.
Agrochemicals are counted among speciality chemicals. | 1 | Applied and Interdisciplinary Chemistry |
Another advantage of poly(pseudo)rotaxanes is the ability for long-term release of drugs or genes. Some polyrotaxanes can used to form a physical hydrogel, which is called supramolecular hydrogel. In these cases, a three-dimensional physically crosslinked network formed by the poly(pseudo)rotaxanes, can be obtained, which is able to retain a large amount of water inside this network. If water-soluble drugs or genes are added in the solution, it could be capsulated in the supramolecular hydrogels. Also, functional units can be employed in the units of the poly(pseudo)rotaxanes, which enhances the interaction between the poly(pseudo)rotaxanes and capsulated drugs/genes and provides the carriers with other predetermined functions. As the network is further swollen in the water-based environment, part of the carrier will be dissolved gradually, so the capsulated drug or gene can be released from the hydrogels over a long period of time. | 0 | Theoretical and Fundamental Chemistry |
Tairus (, a portmanteau of Тайско (Thai) and Русский (Russian)) is a synthetic gemstone manufacturer. It was formed in 1989 as part of Mikhail Gorbachev's perestroika initiative to establish a joint venture between the Russian Academy of Sciences and Tairus Created Gems Co Ltd. of Bangkok, Thailand. Today Tairus is a major supplier of hydrothermally grown gemstones to the jewellery industry. Later, Tairus became a privately held enterprise, operating out of its Bangkok distribution hub under the trade name Tairus, owned by Tairus Created Gems Co Ltd. of Bangkok, Thailand.
In the beginning, the team was led by the scientist and developer of the hydrothermal process, the late Alexander Lebedev, whose name was kept secret by the Soviet regime for many years, and Walter Barshai, who was appointed to be the Chairman of the Board of the Joint Venture Tairus. Their objective was to grow and to supply emeralds, rubies, sapphires, alexandrite and other gems to the jewelry industry. The driving force was late Academician Nikolai Dobretsov, former President of the Siberian Branch of the Russian Academy of Sciences. Tairus has achieved many scientific breakthroughs. For example, the development of the hydrothermally grown corundum, aquamarine and the development of a revolutionary process of horizontal crystallization for growing corundum (ruby), chrysoberyl and alexandrite.
After many years of development, scientists at Tairus had succeeded to commercially grow emeralds in a laboratory environment that resemble in color and have gemological properties that “overlap natural emeralds from various localities, especially those of low alkali-bearing stones from Colombia” ([https://docs.wixstatic.com/ugd/31202c_ba81f0c232274bd6b1183aff1242b3ff.pdf The Journal of Gemmology, 2006, Vol. 30, Nos 1/2, 59-74]). | 0 | Theoretical and Fundamental Chemistry |
Neuroproteomics is the study of the protein complexes and species that make up the nervous system. These proteins interact to make the neurons connect in such a way to create the intricacies that nervous system is known for. Neuroproteomics is a complex field that has a long way to go in terms of profiling the entire neuronal proteome. It is a relatively recent field that has many applications in therapy and science.
So far, only small subsets of the neuronal proteome have been mapped, and then only when applied to the proteins involved in the synapse. | 1 | Applied and Interdisciplinary Chemistry |
Starting point for the Woodward synthesis was the hydroquinone 1 that was converted to cis-bicycle 2 in a Diels-Alder reaction with butadiene. Conversion to the desired trans isomer 5 was accomplished by synthesis of the sodium enolate salt 4 (benzene, sodium hydride) followed by acidification. Reduction (lithium aluminium hydride) then gave diol 6, a dehydration (HCl/water) gave ketol 7, deoxygenation of its acetate by elemental zinc gave enone 8, formylation (ethyl formate) gave enol 9, Michael ethyl vinyl ketone addition (potassium t-butoxide/t-butanol) gave dione 11 which on reaction with KOH in dioxane gave tricycle 12 in an aldol condensation with elimination of the formyl group. In the next series of steps oxidation (osmium tetroxide) gave diol 13, protection (acetone/copper sulfate) gave acetonide 14, hydrogenation (palladium-strontium carbonate) gave 15, formylation (ethyl formate) gave enol 16 which protected as the enamine 17 (N-methylaniline/methanol) gave via the potassium anion 18, carboxylic acid 19 by reaction with cyanoethylene using triton B as the base.
Acid 19 was converted to lactone 20 (acetic anhydride, sodium acetate) and reaction with methylmagnesium chloride gave tetracyclic ketone 21. Treatment with periodic acid (dioxane) and piperidine acetate (benzene) gave aldehyde 24 through diol 22 (oxidation) and dialdehyde 23 (aldol condensation). Sodium dichromate oxidation gave carboxylic acid 25, Diazomethane treatment gave methyl ester 26 and sodium borohydride the allyl alcohol 27. Chiral resolution of this racemic compound with digitonin produced chiral 28 and on Oppenauer oxidation chiral 29. Hydrogenation (Adams' catalyst) gave alcohol 30, chromic acid oxidation gave ketone 31, sodium borohydride reduction stereoselectively gave alcohol 32, hydrolysis followed by acylation gave acetate 33, thionyl chloride treatment gave acyl chloride 34 and methyl cadmium the ketone 35.
In the final stages reaction of 35 with isohexylmagnesium bromide 36 gave diol 37, acetic acid treatment gave dehydration and then hydrogenation gave acetate 38. Hydrolysis of this ester gave cholestanol 39. The route from cholestanol to cholesterol was already known (see: Robinson synthesis). | 0 | Theoretical and Fundamental Chemistry |
He was born in Prague, Czechoslovakia, into a family of some wealth and notability. His undergraduate education began in 1938 when he enrolled to study natural sciences at Charles University. His studies were interrupted the following year when universities were shuttered under the German occupation. Working under the supervision of at Bulovka Hospital, and in a rudimentary laboratory in the basement of his parental home, he discovered a polarographic method of measuring fast chemical reactions. He was awarded a doctorate for this research when Charles University reopened in 1945.
In 1943, he joined a research group at the Fragner pharmaceutical company near Prague that was working to develop a penicillin variant. Despite working in secrecy and isolation under onerous wartime restrictions, the group managed to first separate and then test an antimicrobial drug. Wiesners role included ensuring an adequate supply of the antibiotic by extracting and purifying the substance from the test subjects urine following treatment.
From 1946 until 1948 he conducted postgraduate research in organic chemistry under Vladimir Prelog at ETH, Zürich, funded by a Rockefeller fellowship. Wiesner immigrated to Canada in 1948 to take up a position at the University of New Brunswick, Fredericton. Apart from a two-year spell with the pharmaceutical company Ayerst in Montreal, he remained at UNB for the remainder of his career. In 1981, Wiesner became a founding member of the World Cultural Council. He died of lymphoma in 1986. | 0 | Theoretical and Fundamental Chemistry |
Georges Urbain (12 April 1872 – 5 November 1938) was a French chemist, a professor of the Sorbonne, a member of the Institut de France, and director of the Institute of Chemistry in Paris. Much of his work focused on the rare earths, isolating and separating elements such as europium and gadolinium, and studying their spectra, their magnetic properties and their atomic masses. He discovered the element lutetium (atomic number 71). He also studied the efflorescence of saline hydrates. | 1 | Applied and Interdisciplinary Chemistry |
The 2-O-methylation of the ribose moiety is one of the most common RNA modifications and is present in diverse highly abundant non-coding RNAs (ncRNAs) and at the 5 cap of mRNAs. Moreover, many studies have revealed that Nm at 3’-end is presented in some ncRNAs, such as microRNAs (miRNAs) in plants as well as PIWI-interacting RNAs (piRNAs) in animals.This modification can perturb the function of ribosomes and disrupt tRNA decoding, regulate alternative splicing fidelity, protect ncRNAs from 3’-5’ exonucleolytic degradation and provide a molecular signature for discrimination of self from non-self mRNA. | 1 | Applied and Interdisciplinary Chemistry |
The MARHy Hypersonic low density Wind Tunnel, located at the ICARE Laboratory in Orléans, France, is a research facility used extensively for fundamental and applied research of fluid dynamic phenomena in rarefied compressible flows, applied to space research. Its name is an acronym for Mach Adaptable Rarefied Hypersonic and the wind tunnel is recorded under this name under the European portal MERIL. | 1 | Applied and Interdisciplinary Chemistry |
2,5-diamino-6-hydroxy-4-(5-phosphoribosylamino)pyrimidine is a metabolite in the purine metabolism, formed by the hydrolysis of GTP by GTP cyclohydrolase II. Alternatively two separate enzymes can carry out this reaction, initially GTP cyclohydrolase IIa hydrolyses the 8,9 bond to form 2-Amino-5-formylamino-6-(5-phospho-D-ribosylamino)pyrimidin-4(3H)-one, followed by de-formylation by 2-amino-5-formylamino-6-ribosylaminopyrimidin-4(3H)-one 5'-monophosphate deformylase. 2,5-diamino-6-hydroxy-4-(5-phosphoribosylamino)pyrimidine is deaminated by Diaminohydroxyphosphoribosylaminopyrimidine deaminase to form 5-amino-6-(5-phosphoribosylamino)uracil. | 1 | Applied and Interdisciplinary Chemistry |
Marine sediments represent the main sites of OM degradation and burial in the ocean, hosting microbes in densities up to 1000 times higher than found in the water column. The DOC concentrations in sediments are often an order of magnitude higher than in the overlying water column. This concentration difference results in a continued diffusive flux and suggests that sediments are a major DOC source releasing 350 Tg C yr, which is comparable to the input of DOC from rivers. This estimate is based on calculated diffusive fluxes and does not include resuspension events which also releases DOC and therefore the estimate could be conservative. Also, some studies have shown that geothermal systems and petroleum seepage contribute with pre-aged DOC to the deep ocean basins, but consistent global estimates of the overall input are currently lacking. Globally, groundwaters account for an unknown part of the freshwater DOC flux to the oceans. The DOC in groundwater is a mixture of terrestrial, infiltrated marine, and in situ microbially produced material. This flux of DOC to coastal waters could be important, as concentrations in groundwater are generally higher than in coastal seawater, but reliable global estimates are also currently lacking. | 1 | Applied and Interdisciplinary Chemistry |
The number of adatoms present on a surface is temperature dependent. The relationship between the surface adatom concentration and the temperature at equilibrium is described by equation 4, where n is the total number of surface sites per unit area:
This can be extended to find the equilibrium concentration of other types of surface point defects as well. To do so, the energy of the defect in question is simply substituted into the above equation in the place of the energy of adatom formation. | 0 | Theoretical and Fundamental Chemistry |
The Pharmacogenomics Knowledgebase (PharmGKB) is an "NIH-funded resource that provides information about how human genetic variation affects response to medications. PharmGKB collects, curates and disseminates knowledge about clinically actionable gene-drug associations and genotype-phenotype relationships." | 1 | Applied and Interdisciplinary Chemistry |
Density stratification has significant effect on diffusion in fluids. For example, smoke which is coming from a chimney diffuses turbulently if the earth atmosphere is not stably stratified. When the lower air is in stable condition, as in morning or early evening, the smoke comes out and become flat into a long, thin layer. Strong stratification, or inversions as they are called sometimes, restrict contaminants to the lower regions of the earth atmosphere, and cause many of our current air-pollution problems. | 1 | Applied and Interdisciplinary Chemistry |
FeMoco ( cofactor) is the primary cofactor of nitrogenase. Nitrogenase is the enzyme that catalyzes the conversion of atmospheric nitrogen molecules N into ammonia (NH) through the process known as nitrogen fixation. Studying FeMoco's role in the reaction mechanism for nitrogen fixation is a potential use case for quantum computers. Even limited quantum computers could enable better simulations of the reaction mechanism. Because it contains iron and molybdenum, the cofactor is called FeMoco. Its stoichiometry is FeMoSC. | 0 | Theoretical and Fundamental Chemistry |
Alloys of vanadium, nickel, and titanium have a high hydrogen solubility, and can therefore absorb significant amounts of hydrogen. This can lead to hydride formation, resulting in irregular volume expansion and reduced ductility (because metallic hydrides are fragile ceramic materials). This is a particular issue when looking for non-palladium-based alloys for use in hydrogen separation membranes. | 0 | Theoretical and Fundamental Chemistry |
Thunderstorms can produce a brief pulse of gamma radiation called a terrestrial gamma-ray flash. These gamma rays are thought to be produced by high intensity static electric fields accelerating electrons, which then produce gamma rays by bremsstrahlung as they collide with and are slowed by atoms in the atmosphere. Gamma rays up to 100 MeV can be emitted by terrestrial thunderstorms, and were discovered by space-borne observatories. This raises the possibility of health risks to passengers and crew on aircraft flying in or near thunderclouds. | 0 | Theoretical and Fundamental Chemistry |
Since both boundary conditions for are almost equal to one, one would expect the solution for to slightly deviate from unity. The corresponding scales for and can be derived from the self-similar equations. Therefore,
To the first order approximation(neglecting ), the self-similar equation becomes
with exact solutions
These solution are similar to an Ekman layer solution. | 1 | Applied and Interdisciplinary Chemistry |
Chemiosmosis is the movement of ions across a semipermeable membrane bound structure, down their electrochemical gradient. An important example is the formation of adenosine triphosphate (ATP) by the movement of hydrogen ions (H) across a membrane during cellular respiration or photosynthesis.
Hydrogen ions, or protons, will diffuse from a region of high proton concentration to a region of lower proton concentration, and an electrochemical concentration gradient of protons across a membrane can be harnessed to make ATP. This process is related to osmosis, the movement of water across a selective membrane, which is why it is called "chemiosmosis".
ATP synthase is the enzyme that makes ATP by chemiosmosis. It allows protons to pass through the membrane and uses the free energy difference to convert phosphorylate adenosine diphosphate (ADP) into ATP. The ATP synthase contains two parts: CF0 (present in thylakoid membrane) and CF1 (protrudes on the outer surface of thylakoid membrane). The breakdown of the proton gradient leads to conformational change in CF1—providing enough energy in the process to convert ADP to ATP. The generation of ATP by chemiosmosis occurs in mitochondria and chloroplasts, as well as in most bacteria and archaea. For instance, in chloroplasts during photosynthesis, an electron transport chain pumps H ions (protons) in the stroma (fluid) through the thylakoid membrane to the thylakoid spaces. The stored energy is used to photophosphorylate ADP, making ATP, as protons move through ATP synthase. | 1 | Applied and Interdisciplinary Chemistry |
The stomach contents can also be analyzed. This can help with the post-mortem interval identification by looking at the stage of digestion. The contents can also be analyzed for drugs or poisons to help determine a cause of death if it is unknown. | 1 | Applied and Interdisciplinary Chemistry |
Chirality timeline presents a timeline of landmark events that unfold the developments happened in the field of chirality.
Many molecules come in two forms that are mirror images of each other, just like our hands. This type of molecule is called chiral. In nature, one of these forms is usually more common than the other. In our cells, one of these mirror images of a molecule fits "like a glove," while the other may be harmful.
In nature, molecules with chirality include hormones, DNA, antibodies, and enzymes. For example, (R)-limonene smells like oranges, while (S)-limonene smells like lemons. Both molecules have the same chemical formula, but their spatial orientations are different, which makes a big difference in their biological properties. Chiral molecules in the receptors in our noses can tell the difference between these things. Chirality affects biochemical reactions, and the way a drug works depends on what kind of enantiomer it is. Many drugs are chiral and it is important that the shape of the drug matches the shape of the cell receptor it is meant to affect. Mismatching will make the drug less effective, which could be a matter of life and death, as happened with thalidomide in the 1960s.
It has long been known that structural factors, particularly chirality and stereochemistry, have a big impact on pharmacological efficacy and pharmacokinetic behavior. Since more than a century ago, pertinent information pertaining to chirality has been accumulating in numerous fields, in particular, physics, chemistry and biology, at an accelerated rate, giving rise to more comprehensive and in-depth reasoning, conceptions, and ideas. This page offers a chronology of significant contributions that have been made in the journey of chirality [1809 to 2021]. | 0 | Theoretical and Fundamental Chemistry |
Plants have evolved many secondary metabolites involved in plant defense, which are collectively known as antiherbivory compounds and can be classified into three sub-groups: nitrogen compounds (including alkaloids, cyanogenic glycosides, glucosinolates and benzoxazinoids), terpenoids, and phenolics.
Alkaloids are derived from various amino acids. Over 3000 known alkaloids exist, examples include nicotine, caffeine, morphine, cocaine, colchicine, ergolines, strychnine, and quinine. Alkaloids have pharmacological effects on humans and other animals. Some alkaloids can inhibit or activate enzymes, or alter carbohydrate and fat storage by inhibiting the formation phosphodiester bonds involved in their breakdown. Certain alkaloids bind to nucleic acids and can inhibit synthesis of proteins and affect DNA repair mechanisms. Alkaloids can also affect cell membrane and cytoskeletal structure causing the cells to weaken, collapse, or leak, and can affect nerve transmission. Although alkaloids act on a diversity of metabolic systems in humans and other animals, they almost uniformly invoke an aversively bitter taste.
Cyanogenic glycosides are stored in inactive forms in plant vacuoles. They become toxic when herbivores eat the plant and break cell membranes allowing the glycosides to come into contact with enzymes in the cytoplasm releasing hydrogen cyanide which blocks cellular respiration. Glucosinolates are activated in much the same way as cyanogenic glucosides, and the products can cause gastroenteritis, salivation, diarrhea, and irritation of the mouth. Benzoxazinoids, such as DIMBOA, are secondary defence metabolites characteristic of certain grasses (Poaceae). Like cyanogenic glycosides, they are stored as inactive glucosides in the plant vacuole. Upon tissue disruption they get into contact with β-glucosidases from the chloroplasts, which enzymatically release the toxic aglucones. Whereas some benzoxazinoids are constitutively present, others are only synthesized following herbivore infestation, and thus, considered inducible plant defenses against herbivory.
The terpenoids, sometimes referred to as isoprenoids, are organic chemicals similar to terpenes, derived from five-carbon isoprene units. There are over 10,000 known types of terpenoids. Most are multicyclic structures which differ from one another in both functional groups, and in basic carbon skeletons. Monoterpenoids, containing 2 isoprene units, are volatile essential oils such as citronella, limonene, menthol, camphor, and pinene. Diterpenoids, 4 isoprene units, are widely distributed in latex and resins, and can be quite toxic. Diterpenes are responsible for making Rhododendron leaves poisonous. Plant steroids and sterols are also produced from terpenoid precursors, including vitamin D, glycosides (such as digitalis) and saponins (which lyse red blood cells of herbivores).
Phenolics, sometimes called phenols, consist of an aromatic 6-carbon ring bonded to a hydroxy group. Some phenols have antiseptic properties, while others disrupt endocrine activity. Phenolics range from simple tannins to the more complex flavonoids that give plants much of their red, blue, yellow, and white pigments. Complex phenolics called polyphenols are capable of producing many different types of effects on humans, including antioxidant properties. Some examples of phenolics used for defense in plants are: lignin, silymarin and cannabinoids. Condensed tannins, polymers composed of 2 to 50 (or more) flavonoid molecules, inhibit herbivore digestion by binding to consumed plant proteins and making them more difficult for animals to digest, and by interfering with protein absorption and digestive enzymes.
In addition, some plants use fatty acid derivatives, amino acids and even peptides as defenses. The cholinergic toxin, cicutoxin of water hemlock, is a polyyne derived from the fatty acid metabolism. Oxalyldiaminopropionic acid is a neurotoxic amino acid produced as a defensive metabolite in the grass pea (Lathyrus sativus). The synthesis of fluoroacetate in several plants is an example of the use of small molecules to disrupt the metabolism of herbivores, in this case the citric acid cycle. | 1 | Applied and Interdisciplinary Chemistry |
It has been revealed by unclassified official sources that Fogbank was originally manufactured in Facility 9404-11 of the Y-12 National Security Complex in Oak Ridge, Tennessee, from 1975 until 1989, when the final batch of W76 warheads was completed. After that, the facility was deactivated, and finally slated for decommissioning by 1993. Only a small pilot plant was left, which had been used to produce small batches of Fogbank for testing purposes.
In 1996, the US government decided to replace, refurbish, or decommission large numbers of its nuclear weapons. Accordingly, the Department of Energy established a refurbishment program to extend the service lives of older nuclear weapons. In 2000, the NNSA specified a life-extension program for W76 warheads that would enable them to remain in service until at least 2040.
It was soon realized that the Fogbank material was a potential source of problems for the program, as few records of its manufacturing process had been retained when it was originally manufactured in the 1980s, and nearly all staff members who had expertise in its production had either retired or left the agency. The NNSA briefly investigated sourcing a substitute for Fogbank, but eventually decided that since Fogbank had been produced previously, they would be able to repeat it. Additionally, "Los Alamos computer simulations at that time were not sophisticated enough to determine conclusively that an alternate material would function as effectively as Fogbank," according to a Los Alamos publication.
Manufacture involves the moderately toxic, highly volatile solvent acetonitrile, which presents a hazard for workers (causing three evacuations in March 2006 alone).
With Facility 9404-11 long since decommissioned, a new production facility was required. Delays arose during its construction. Engineers repeatedly encountered failure in their efforts to produce Fogbank. As multiple deadlines expired, and the schedule was pushed back repeatedly, the NNSA eventually invested $23 million to find an alternative to Fogbank.
In March 2007, engineers devised a manufacturing process for Fogbank. Unfortunately, the material turned out to have problems when tested, and in September 2007 the Fogbank project was upgraded to "Code Blue" status by the NNSA, making it a major priority. In 2008, following the expenditure of a further $69 million, the NNSA finally managed to manufacture Fogbank, and 7 months later, the first refurbished warhead was provided to the US Navy, nearly a decade after the commencement of the refurbishment program. In May 2009 a US Navy spokesman said that they had not received any refurbished weapons. The Energy Department stated that the current plan was to begin shipping refurbished weapons in the fall of 2009, two years behind schedule.
The experience of reverse engineering Fogbank produced some improvements in scientific knowledge of the process. The new production scientists noticed that certain problems in production resembled those noted by the original team. These problems were traced to a particular impurity in the final product that was required to meet quality standards. A root cause investigation showed that input materials were subject to cleaning processes that had not existed during the original production run. This cleaning removed a substance that generated the required impurity. With the implicit role of this substance finally understood, the production scientists could control output quality better than during the original run.
The W76 life-extension project was completed in December 2018, when 800 W76s were upgraded to the W76-1 design. It is unclear whether the new W76-2 uses Fogbank. | 0 | Theoretical and Fundamental Chemistry |
These proteins were originally characterized by their capacity to induce oncogenic transformation in a specific cell culture system, rat kidney fibroblasts. Application of the transforming growth factors to normal rat kidney fibroblasts induces the cultured cells to proliferate and overgrow, no longer subject to the normal inhibition caused by contact between cells. | 1 | Applied and Interdisciplinary Chemistry |
Eukaryotic Initiation Factor 2 (eIF2) is an eukaryotic initiation factor. It is required for most forms of eukaryotic translation initiation. eIF2 mediates the binding of tRNA to the ribosome in a GTP-dependent manner. eIF2 is a heterotrimer consisting of an alpha (also called subunit 1, EIF2S1), a beta (subunit 2, EIF2S2), and a gamma (subunit 3, EIF2S3) subunit.
Once the initiation phase has completed, eIF2 is released from the ribosome bound to GDP as an inactive binary complex. To participate in another round of translation initiation, this GDP must be exchanged for GTP. | 1 | Applied and Interdisciplinary Chemistry |
The extraction cells consist of hollow bodies with inlets and outlets of liquid connection. The cells are first filled with the liquid chosen to be the stationary phase. Under rotation, the pumping of the mobile phase is started, which enters the cells from the inlet. When entering the flow of mobiles phase forms small droplets according to the Stokes' law, which is called atomization. These droplets fall through the stationary phase, creating a high interface area, which is called the extraction. At the end of the cells, these droplets unite due to the surface tension, which is called settling.
When a sample mixture is injected as a plug into the flow of mobile phase the compounds of the mixtures elute according to their partition coefficients:
Centrifugal partition chromatography requires only a biphasic mixture of solvents, so by varying the constitution of the solvent system it is possible to tune the partition coefficients of different compounds so that separation is guaranteed by the high selectivity. | 0 | Theoretical and Fundamental Chemistry |
In recent years Raman-SEC has become an important tool in the study of electrochemical processes and in the characterization of many molecules, providing specific in situ information about them. Some applications are:
* Materials: Raman-SEC is widely used in the study and characterization of new materials, such as graphene, carbon nanotubes or conductive polymers, among others. It is also applied in the study of dyes, organic molecules capable of forming monolayers on the electrode, and in the study of proteins.
* Qualitative and quantitative analysis: Raman-SEC can be applied to highly complex samples, such as the detection of melamine in milk, the identification of bacteria, the detection of DNA biomarkers and/or uric acid in urine, among others. In addition, very low concentrations can be detected.
* Energy. Raman-SEC were used in the study of solar cells, batteries and catalysts for fuel cells.
* Transfer processes at the liquid/liquid interfaces: Raman-SEC is used to monitor ion or electron transfer processes at polarizable interfaces between immiscible electrolyte solutions. | 0 | Theoretical and Fundamental Chemistry |
The first rule holds that a double-stranded DNA molecule, globally has percentage base pair equality: A% = T% and G% = C%. The rigorous validation of the rule constitutes the basis of Watson–Crick base pairs in the DNA double helix model. | 1 | Applied and Interdisciplinary Chemistry |
Satoyasu Iimori (19 October 1885 – 13 October 1982) was a Japanese analytical chemist and a pioneer of radiochemistry. He is so called "the father of radiochemistry in Japan", for his establishment of and contribution to the study of radiochemistry which was not developed at that time in Japan.
He was an honorary research member of the Institute of Physical and Chemical Research (RIKEN) and also an honorary member of the Chemical Society of Japan as well as the Society of the Analytical Chemistry of Japan. After his retirement as a researcher, he became interested in the synthesis of artificial gemstones. | 0 | Theoretical and Fundamental Chemistry |
Entropic gravity, as proposed by Verlinde in his original article, reproduces the Einstein field equations and, in a Newtonian approximation, a potential for gravitational forces. Since its results do not differ from Newtonian gravity except in regions of extremely small gravitational fields, testing the theory with earth-based laboratory experiments does not appear feasible. Spacecraft-based experiments performed at Lagrangian points within our solar system would be expensive and challenging.
Even so, entropic gravity in its current form has been severely challenged on formal grounds. Matt Visser has shown that the attempt to model conservative forces in the general Newtonian case (i.e. for arbitrary potentials and an unlimited number of discrete masses) leads to unphysical requirements for the required entropy and involves an unnatural number of temperature baths of differing temperatures. Visser concludes:
For the derivation of Einsteins equations from an entropic gravity perspective, Tower Wang shows that the inclusion of energy-momentum conservation and cosmological homogeneity and isotropy requirements severely restricts a wide class of potential modifications of entropic gravity, some of which have been used to generalize entropic gravity beyond the singular case of an entropic model of Einsteins equations. Wang asserts that:
Cosmological observations using available technology can be used to test the theory. On the basis of lensing by the galaxy cluster Abell 1689, Nieuwenhuizen concludes that EG is strongly ruled out unless additional (dark) matter-like eV neutrinos is added. A team from Leiden Observatory statistically observing the lensing effect of gravitational fields at large distances from the centers of more than 33,000 galaxies found that those gravitational fields were consistent with Verlindes theory. Using conventional gravitational theory, the fields implied by these observations (as well as from measured galaxy rotation curves) could only be ascribed to a particular distribution of dark matter. In June 2017, a study by Princeton University researcher Kris Pardo asserted that Verlindes theory is inconsistent with the observed rotation velocities of dwarf galaxies. Another theory of entropy based on geometric considerations (Quantitative Geometrical Thermodynamics, QGT) provides an entropic basis for the holographic principle and also offers another explanation for galaxy rotation curves as being due to the entropic influence of the central supermassive blackhole found in the center of a spiral galaxy.
In 2018, Zhi-Wei Wang and Samuel L. Braunstein showed that, while spacetime surfaces near black holes (called stretched horizons) do obey an analog of the first law of thermodynamics, ordinary spacetime surfaces — including holographic screens — generally do not, thus undermining the key thermodynamic assumption of the emergent gravity program.
In his 1964 lecture on the Relation of Mathematics and Physics, Richard Feynman describes a related theory for gravity where the gravitational force is explained due to an entropic force due to unspecified microscopic degrees of freedom. However, he immediately points out that the resulting theory cannot be correct as the fluctuation-dissipation theorem would also lead to friction which would slow down the motion of the planets which contradicts observations. | 0 | Theoretical and Fundamental Chemistry |
Although all commercially available DBU is produced synthetically, it may also be isolated from the sea sponge Niphates digitalis. The biosynthesis of DBU has been proposed to begin with adipaldehyde and 1,3-diaminopropane. | 0 | Theoretical and Fundamental Chemistry |
Needham and Lu's third justification for taking poisonous elixirs is a drug-induced "temporary death", possibly a trance or coma. In the classic legend (above) about Wei Boyang drinking an elixir of immortality, he appears to die, subsequently revives, and takes more elixir to achieve immortality.
The Baopuzi describes a Five Mineral-based multicolored Ninefold Radiance Elixir that can bring a corpse back to life: "If you wish to raise a body that has not been dead for fully three days, bathe the corpse with a solution of one spatula of the blue elixir, open its mouth, and insert another spatula full; it will revive immediately.".
A Tang Daoist text prescribes taking an elixir in doses half the size of a millet grain, but adds, "If one is sincerely determined, and dares to take a whole spatula-full all at once, one will temporarily die [zànsǐ 暫死] for half a day or so, and then be restored to life like someone waking from sleep. This however is perilous in the extreme". | 1 | Applied and Interdisciplinary Chemistry |
In the highly versatile and widely used Evans’ Aldol Reaction, allylic strain played a major role in the development of the reaction. The Z enolate was created to avoid the allylic strain with oxazolidinone. The formation of a specific enolate enforces the development of relative stereochemistry throughout the reaction, making the aldol reaction a very predictive and useful methodology out there to synthesize chiral molecules. The absolute stereochemistry is then determined by the chirality of the oxazolidinone.
There is another aspect of aldol reaction that is influenced by the allylic strain. On the second aldol reaction, the product which is a 1,3 dicarbonyl is formed in high diastereoselectivity. This is because the acidity of the proton is significantly reduced because for the deprotonation to occur, it will have to go through a developing allylic strain in the unfavored conformation. In the favored conformation, the proton is not aligned properly for deprotonation to occur. | 0 | Theoretical and Fundamental Chemistry |
In industrial process, the control of the quality of process water can be critical to the quality of the end product. Water is often used as a carrier of reagents and the loss of reagent to product must be continuously monitored to ensure that correct replacement rate. Parameters measured relate specifically to the process in use and to any of the expected contaminants that may arise as by-products. This may include unwanted organic chemicals appearing in an inorganic chemical process through contamination with oils and greases from machinery. Monitoring the quality of the waste water discharged from industrial premises is a key factor in controlling and minimising pollution of the environment. In this application monitoring schemes analyse for all possible contaminants arising within the process and in addition contaminants that may have particularly adverse impacts on the environment such as cyanide and many organic species such as pesticides. In then nuclear industry analysis focuses on specific isotopes or elements of interest. Where the nuclear industry makes waste water discharges to rivers which have drinking water abstraction on them, radio-isotopes which could potentially be harmful or those with long half-lives such as tritium will form part of the routine monitoring suite. | 0 | Theoretical and Fundamental Chemistry |
The Dunaverney (1050–910 BC) and Little Thetford (1000–701 BC) flesh-hooks have been shown to be made using a lost-wax process. The Little Thetford flesh-hook, in particular, employed distinctly inventive construction methods. The intricate Gloucester Candlestick (1104–1113 AD) was made as a single-piece wax model, then given a complex system of gates and vents before being invested in a mould. | 1 | Applied and Interdisciplinary Chemistry |
In physics, a fluid is a liquid, gas, or other material that may continuously move and deform (flow) under an applied shear stress, or external force. They have zero shear modulus, or, in simpler terms, are substances which cannot resist any shear force applied to them.
Although the term fluid generally includes both the liquid and gas phases, its definition varies among branches of science. Definitions of solid vary as well, and depending on field, some substances can have both fluid and solid properties. Non-Newtonian fluids like Silly Putty appear to behave similar to a solid when a sudden force is applied. Substances with a very high viscosity such as pitch appear to behave like a solid (see pitch drop experiment) as well. In particle physics, the concept is extended to include fluidic matters other than liquids or gases. A fluid in medicine or biology refers to any liquid constituent of the body (body fluid), whereas "liquid" is not used in this sense. Sometimes liquids given for fluid replacement, either by drinking or by injection, are also called fluids (e.g. "drink plenty of fluids"). In hydraulics, fluid is a term which refers to liquids with certain properties, and is broader than (hydraulic) oils. | 1 | Applied and Interdisciplinary Chemistry |
Inoculate MacConkey's (Glucose phosphate broth) with pure culture of test organism. Incubate the broth at 35 °C for 48–72 hours.
After incubation add 5 drops of methyl red directly into the broth, through the sides of the tube. | 0 | Theoretical and Fundamental Chemistry |
Hydrates are ionic compounds that have absorbed water. They are named as the ionic compound followed by a numerical prefix and -hydrate. The numerical prefixes used are listed below (see IUPAC numerical multiplier):
# mono-
# di-
# tri-
# tetra-
# penta-
# hexa-
# hepta-
# octa-
# nona-
# deca-
For example, CuSO·5HO is "copper(II) sulfate pentahydrate". | 0 | Theoretical and Fundamental Chemistry |
The antibodies from lymphocyte secretions (ALS) assay is an immunological assay to detect active diseases like tuberculosis, cholera, typhoid etc. Recently, ALS assay nods the scientific community as it is rapidly used for diagnosis of Tuberculosis. The principle is based on the secretion of antibody from in vivo activated plasma B cells found in blood circulation for a short period of time in response to TB-antigens during active TB infection rather than latent TB infection. | 1 | Applied and Interdisciplinary Chemistry |
Scarlett was born 11 July 1938 in Biddulph, Staffordshire, England.
He attended Wolstanton Grammar School and the University of Durham, gaining a BSc in physics in 1959. By 1964 Scarlett had earned a PhD from the same institution, having also migrated from Hatfield College to University College for his doctoral studies.
He died 2 September 2004 in Gainesville, Florida, being survived by his wife Joan, son Ian, and daughters Diane and Judy. | 1 | Applied and Interdisciplinary Chemistry |
The most common physical methods used to lyse, kill, and remove cells from the matrix of a tissue through the use of temperature, force and pressure, and electrical disruption. Temperature methods are often used in a rapid freeze-thaw mechanism. By quickly freezing a tissue, microscopic ice crystals form around the plasma membrane and the cell is lysed. After lysing the cells, the tissue can be further exposed to liquidized chemicals that degrade and wash out the undesirable components. Temperature methods conserve the physical structure of the ECM scaffold, but are best handled by thick, strong tissues.
Direct force of pressure to a tissue will guarantee disruption of the ECM structure, so pressure is commonly used. Pressure decellularization involves the controlled use of hydrostatic pressure applied to a tissue or organ. This is done best at high temperatures to avoid unmonitored ice crystal formation that could damage the scaffold. Electrical disruption of the plasma membrane is another option to lyse the cells housed in a tissue or organ. By exposing a tissue to electrical pulses, micropores are formed at the plasma membrane. The cells eventually turn to death after their homeostatic electrical balance is ruined through the applied stimulus. This electrical process is documented as Non-thermal irreversible electroporation (NTIRE) and is limited to small tissues and the limited possibilities of inducing an electric current in vivo. | 1 | Applied and Interdisciplinary Chemistry |
Fung's famous exponential strain constitutive equation for preconditioned soft tissues is
with
quadratic forms of Green-Lagrange strains and , and material constants. is a strain energy function per volume unit, which is the mechanical strain energy for a given temperature. Materials that follow this law are known as Fung-elastic. | 1 | Applied and Interdisciplinary Chemistry |
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