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In bacteria, the coding regions typically take up 88% of the genome. The remaining 12% does not encode proteins, but much of it still has biological function through genes where the RNA transcript is functional (non-coding genes) and regulatory sequences, which means that almost all of the bacterial genome has a function. The amount of coding DNA in eukaryotes is usually a much smaller fraction of the genome because eukaryotic genomes contain large amounts of repetitive DNA not found in prokaryotes. The human genome contains somewhere between 1–2% coding DNA. The exact number is not known because there are disputes over the number of functional coding exons and over the total size of the human genome. This means that 98–99% of the human genome consists of non-coding DNA and this includes many functional elements such as non-coding genes and regulatory sequences.
Genome size in eukaryotes can vary over a wide range, even between closely related species. This puzzling observation was originally known as the C-value Paradox where "C" refers to the haploid genome size. The paradox was resolved with the discovery that most of the differences were due to the expansion and contraction of repetitive DNA and not the number of genes. Some researchers speculated that this repetitive DNA was mostly junk DNA. The reasons for the changes in genome size are still being worked out and this problem is called the C-value Enigma.
This led to the observation that the number of genes does not seem to correlate with perceived notions of complexity because the number of genes seems to be relatively constant, an issue termed the G-value Paradox. For example, the genome of the unicellular Polychaos dubium (formerly known as Amoeba dubia) has been reported to contain more than 200 times the amount of DNA in humans (i.e. more than 600 billion pairs of bases vs a bit more than 3 billion in humans). The pufferfish Takifugu rubripes genome is only about one eighth the size of the human genome, yet seems to have a comparable number of genes. Genes take up about 30% of the pufferfish genome and the coding DNA is about 10%. (Non-coding DNA = 90%.) The reduced size of the pufferfish genome is due to a reduction in the length of introns and less repetitive DNA.
Utricularia gibba, a bladderwort plant, has a very small nuclear genome (100.7 Mb) compared to most plants. It likely evolved from an ancestral genome that was 1,500 Mb in size. The bladderwort genome has roughly the same number of genes as other plants but the total amount of coding DNA comes to about 30% of the genome.
The remainder of the genome (70% non-coding DNA) consists of promoters and regulatory sequences that are shorter than those in other plant species. The genes contain introns but there are fewer of them and they are smaller than the introns in other plant genomes. There are noncoding genes, including many copies of ribosomal RNA genes. The genome also contains telomere sequences and centromeres as expected. Much of the repetitive DNA seen in other eukaryotes has been deleted from the bladderwort genome since that lineage split from those of other plants. About 59% of the bladderwort genome consists of transposon-related sequences but since the genome is so much smaller than other genomes, this represents a considerable reduction in the amount of this DNA. The authors of the original 2013 article note that claims of additional functional elements in the non-coding DNA of animals do not seem to apply to plant genomes.
According to a New York Times article, during the evolution of this species, "... genetic junk that didn't serve a purpose was expunged, and the necessary stuff was kept." According to Victor Albert of the University of Buffalo, the plant is able to expunge its so-called junk DNA and "have a perfectly good multicellular plant with lots of different cells, organs, tissue types and flowers, and you can do it without the junk. Junk is not needed." | 1 | Applied and Interdisciplinary Chemistry |
One of the highest, at least in Western Europe, is in Loos-en-Gohelle in the former mining area of Pas-de-Calais, France. It comprises a range of five cones, of which two reach , surpassing the highest peak in Flanders, Mont Cassel. One of the regions of Europe most "littered" with (mountainous) spoil heaps is the Donbas, in Ukraine, especially around the city of Donetsk, which alone boasts about 130 of them.
In Ukrainian, they are called (; singular ) because of their shape.
In Heringen, Hesse, Germany, is the popularly called "Monte Kali", made of spoil from potash mining and rising some 200 meters above the surrounding terrain. "La Muntanya de Sal" (The Salt Mountain), another potash mine spoil heap, lies in Cardona, Catalonia, at about 120 meters in height. A larger and higher pile is that of "El runam del Cogulló" (The Spoil Heap of El Cogulló), also known as "El runam de la democràcia" (The Slag Heap of Democracy) or "Montsalat" (Salty Mountain), in Sallent, which has already grown higher than the small mountain it was named after (El Cogulló, 474 meters above sea level). | 1 | Applied and Interdisciplinary Chemistry |
According to Lord Kelvin's equation of 1871,
If the particle is assumed to be spherical, then ; hence,
Note: Kelvin defined the surface tension as the work that was performed per unit area by the interface rather than on the interface; hence his term containing has a minus sign. In what follows, the surface tension will be defined so that the term containing has a plus sign.
Since , then ; hence,
Assuming that the vapor obeys the ideal gas law, then
where:
: = mass of a volume of vapor
: = molecular weight of vapor
: = number of moles of vapor in volume of vapor
: = Avogadro constant
: = ideal gas constant =
Since is the mass of one molecule of vapor or liquid, then
: volume of one molecule .
Hence
: where .
Thus
Since
then
Since , then . If , then . Hence
Therefore
which is the Ostwald–Freundlich equation. | 0 | Theoretical and Fundamental Chemistry |
Some instances of ancient use of fluorite, main source mineral of fluorine, for ornamental use carvings exist. However, archeological finds are rare, perhaps in part because of the stone's softness. Two Roman cups made of Persian fluorite have been discovered and are currently exhibited at the British museum. Pliny the Elder described a soft stone from Persia used in cups that may have been fluorite. Fluorite carvings from about 1000 AD have been discovered in the Americas in Indian burial grounds. | 1 | Applied and Interdisciplinary Chemistry |
The global steel industry has been going through major changes since 1970. China has emerged as a major producer and consumer, as has India to a lesser extent. Consolidation has been rapid in Europe. According to the 2019 International Energy Agency (IEA) report, the iron and steel industry directly contributed 2.6 Gt to global CO emissions and accounted for 7% of global energy demand. Singapore is the worlds main trading hub for iron, with about 90% of the worlds iron ore derivatives traded on their stock exchange. | 1 | Applied and Interdisciplinary Chemistry |
New vaccines against currently circulating influenza variants are required every year due to the diversity of flu viruses and variable efficacy of vaccines to prevent them. A universal vaccine would eliminate the need to create a vaccine for each year's variants. The efficacy of a vaccine refers to the protection against a broad variety of influenza strains. Events such as antigenic shift have created pandemic strains such as the H1N1 outbreak in 2009. The research required every year to isolate a potential popular viral strain and create a vaccine to defend against it is a six-month-long process; during that time the virus can mutate, making the vaccines less effective.
High-risk populations, including the elderly and those with chronic disease, often acquire only limited immunity towards the flu from vaccines. The vaccines have been found to be 30% to 70% effective in preventing hospitalization from the flu or pneumonia.
On average influenza vaccine efficacy is 60% among the general population that receive yearly vaccinations.
A universal vaccine could be manufactured in quantity and eliminate availability and supply issues of current vaccines. There is conflicting evidence on whether it would cut costs. | 1 | Applied and Interdisciplinary Chemistry |
# Anaerobic Digestion: Micro-organisms decompose the sludge in the absence of oxygen either at mesophilic (at 35 °C) or thermophilic (between 50° and 57 °C) temperatures.
# Aerobic Digestion: Micro-organisms decompose the sludge in the presence of oxygen either at ambient and mesophilic (10 °C to 40 °C) or auto-thermal (40 °C to 80 °C) temperatures.
# Composting: A biological process where organic matter decomposes to produce humus after the addition of some dry bulking material such as sawdust, wood chips, or shredded yard waste under controlled aerobic conditions.
# Alkaline Treatment: The sludge is mixed with alkaline materials such as lime or cement kiln dust, or incinerator fly ash and maintained at pH above 12 for 24 hours (for Class B) or at temperature 70 °C for 30 minutes (for Class A).
# Heat Drying: Either convention or conduction dryers are used to dry the biosolids
# Dewatering: The separation of the water from biosolids is done to obtain a semi-solid or solid product by using a dewatering technologies (centrifuges, belt filter presses, plate and frame filter presses, and drying beds and lagoons). | 1 | Applied and Interdisciplinary Chemistry |
The Loss of Fluid Tests (LOFT) were an early attempt to scope the response of real nuclear fuel to conditions under a loss-of-coolant accident, funded by USNRC. The facility was built at Idaho National Laboratory, and was essentially a scale-model of a commercial PWR. (Power/volume scaling was used between the LOFT model, with a 50MWth core, and a commercial plant of 3000MWth).
The original intention (1963–1975) was to study only one or two major (large break) LOCA, since these had been the main concern of US rule-making hearings in the late 1960s and early 1970s. These rules had focussed around a rather stylised large-break accident, and a set of criteria (e.g. for extent of fuel-clad oxidation) set out in Appendix K of 10CFR50 (Code of Federal Regulations). Following the accident at Three Mile Island, detailed modelling of much smaller LOCA became of equal concern.
38 LOFT tests were eventually performed and their scope was broadened to study a wide spectrum of breach sizes. These tests were used to help validate a series of computer codes (such as RELAP-4, RELAP-5 and TRAC) then being developed to calculate the thermal-hydraulics of LOCA. | 0 | Theoretical and Fundamental Chemistry |
Process upsets are temporary decreases in treatment plant performance caused by significant population change within the secondary treatment ecosystem. Conditions likely to create upsets include toxic chemicals and unusually high or low concentrations of organic waste BOD providing food for the bioreactor ecosystem.
Measures creating uniform wastewater loadings tend to reduce the probability of upsets. Fixed-film or attached growth secondary treatment bioreactors are similar to a plug flow reactor model circulating water over surfaces colonized by biofilm, while suspended-growth bioreactors resemble a continuous stirred-tank reactor keeping microorganisms suspended while water is being treated. Secondary treatment bioreactors may be followed by a physical phase separation to remove biological solids from the treated water. Upset duration of fixed film secondary treatment systems may be longer because of the time required to recolonize the treatment surfaces. Suspended growth ecosystems may be restored from a population reservoir. Activated sludge recycle systems provide an integrated reservoir if upset conditions are detected in time for corrective action. Sludge recycle may be temporarily turned off to prevent sludge washout during peak storm flows when dilution keeps BOD concentrations low. Suspended growth activated sludge systems can be operated in a smaller space than fixed-film trickling filter systems that treat the same amount of water; but fixed-film systems are better able to cope with drastic changes in the amount of biological material and can provide higher removal rates for organic material and suspended solids than suspended growth systems.
Wastewater flow variations may be reduced by limiting stormwater collection by the sewer system, and by requiring industrial facilities to discharge batch process wastes to the sewer over a time interval rather than immediately after creation. Discharge of appropriate organic industrial wastes may be timed to sustain the secondary treatment ecosystem through periods of low residential waste flow. Sewage treatment systems experiencing holiday waste load fluctuations may provide alternative food to sustain secondary treatment ecosystems through periods of reduced use. Small facilities may prepare a solution of soluble sugars. Others may find compatible agricultural wastes, or offer disposal incentives to septic tank pumpers during low use periods. | 1 | Applied and Interdisciplinary Chemistry |
The amount of time it takes for water to be filtered through air stripping can vary from system to system depending on the size of the tank or how quickly water can flow through the device. The typical amount of time water takes to be filtered is around a few minutes. Though, other studies suggest that it can take far longer depending on the type of and concentration of substance. For instance, higher levels of NH3-N, a common contaminant in ground water, can take several hours of air stripping in order to be properly removed from water. In a recent study, it took 4 hours to for the air stripper to reach an equilibrium of efficiency in removing NH3-N elements, topping off at an 81.9% removal rate. Comparatively, only 30.7% of NH3-N elements were removed at 10 minutes, suggesting that removal of contaminants of water correlates with the amount of time spent air stripping. | 1 | Applied and Interdisciplinary Chemistry |
NaK has been used as the coolant in experimental fast neutron nuclear reactors. Unlike commercial plants, these are frequently shut down and defuelled. Use of lead or pure sodium, the other materials used in practical reactors, would require continual heating to maintain the coolant as a liquid. Use of NaK overcomes this. The Dounreay Fast Reactor is an example.
The Soviet RORSAT radar satellites were powered by a BES-5 reactor, which was cooled with NaK. In addition to the wide liquid temperature range, NaK has a very low vapor pressure, which is important in the vacuum of space.
An unintended consequence of the usage as a coolant on orbiting satellites has been the creation of additional space debris. NaK coolant has leaked from a number of satellites, including Kosmos 1818 and Kosmos 1867. The coolant self-forms into droplets of sodium–potassium of up to several centimeters in size. These objects are space debris.
The Danamics LMX Superleggera CPU cooler uses NaK to transport heat from the CPU to its cooling fins. | 1 | Applied and Interdisciplinary Chemistry |
Motor proteins utilizing the cytoskeleton for movement fall into two categories based on their substrate: microfilaments or microtubules. Actin motors such as myosin move along microfilaments through interaction with actin, and microtubule motors such as dynein and kinesin move along microtubules through interaction with tubulin.
There are two basic types of microtubule motors: plus-end motors and minus-end motors, depending on the direction in which they "walk" along the microtubule cables within the cell. | 0 | Theoretical and Fundamental Chemistry |
Technetium exits the generator in the form of the pertechnetate ion, TcO. The oxidation state of Tc in this compound is +7. This is directly suitable for medical applications only in bone scans (it is taken up by osteoblasts) and some thyroid scans (it is taken up in place of iodine by normal thyroid tissues). In other types of scans relying on Tc, a reducing agent is added to the pertechnetate solution to bring the oxidation state of the technecium down to +3 or +4. Secondly, a ligand is added to form a coordination complex. The ligand is chosen to have an affinity for the specific organ to be targeted. For example, the exametazime complex of Tc in oxidation state +3 is able to cross the blood–brain barrier and flow through the vessels in the brain for cerebral blood flow imaging. Other ligands include sestamibi for myocardial perfusion imaging and mercapto acetyl triglycine for MAG3 scan to measure renal function. | 0 | Theoretical and Fundamental Chemistry |
Vanadyl ribonucleoside is a potent transition-state analog of ribonucleic acid and potent inhibitor of many species of ribonuclease formed from a vanadium coordination complex and one ribonucleoside. Vanadium's [ 4s electron configuration allows it to make five sigma bonds and two pi bonds with adjacent atoms. | 1 | Applied and Interdisciplinary Chemistry |
A flow promotes mixing by separating neighboring fluid particles. This separation occurs because of velocity gradients, a phenomenon called shearing. Let and be two neighboring fluid particles, separated by at time t. When the particles are advected by a flow , at time the approximate separation between the particles can be found through Taylor expansion :
hence
and
The rate of growth of the separation is therefore given by the gradient of the velocity field in the direction of the separation. The plane shear flow is a simple example of large-scale stationary flow that deforms fluid elements because of a uniform shear. | 1 | Applied and Interdisciplinary Chemistry |
A primary concern with the use of ionic liquids for carbon capture is their high viscosity compared with that of commercial solvents. Ionic liquids which employ chemisorption depend on a chemical reaction between solute and solvent for CO separation. The rate of this reaction is dependent on the diffusivity of CO in the solvent and is thus inversely proportional to viscosity. The self diffusivity of CO in ionic liquids are generally to the order of 10 m/s, approximately an order of magnitude less than similarly performing commercial solvents used on CO capture. The viscosity of an ionic liquid can vary significantly according to the type of anion and cation, the alkyl chain length, and the amount of water or other impurities in the solvent. Because these solvents can be “designed” and these properties chosen, developing ionic liquids with lowered viscosities is a current topic of research. Supported ionic liquid phases (SILPs) are one proposed solution to this problem. | 0 | Theoretical and Fundamental Chemistry |
Sustainable Engineering focuses on the following -
* Water supply
* Food production
* Housing and shelter
* Sanitation and waste management
* Energy development
* Transportation
* Industrial processing
* Development of natural resources
* Cleaning up polluted waste sites
* Planning projects to reduce environmental and social impacts
* Restoring natural environments such as forests, lakes, streams, and wetlands
* Providing medical care to those in need
* Minimizing and responsibly disposing of waste to benefit all
* Improving industrial processes to eliminate waste and reduce consumption
* Recommending the appropriate and innovative use of technology | 1 | Applied and Interdisciplinary Chemistry |
Due to the presence of two types of oxygen atoms in the PPA backbone, in addition to the fact that H tends to protonate oxygen atoms easily, depolymerization can occur through both endcap cleavage and protonation of oxygen atoms present in the backbone. For this reason, polymer chemists tend to use endcaps rich in oxygen atoms to accelerate depolymerization rate. For example, Moore and co-workers reported the use of a specific ion coactivation (SICA) effect that allowed the ion and acid coactivated-triggered depolymerization of a cyclic PPA microcapsules at the solid/liquid interface of the polymer and solution. | 0 | Theoretical and Fundamental Chemistry |
Tissue remodeling is the reorganization or renovation of existing tissues. Tissue remodeling can be either physiological or pathological. The process can either change the characteristics of a tissue such as in blood vessel remodeling, or result in the dynamic equilibrium of a tissue such as in bone remodeling. Macrophages repair wounds and remodel tissue by producing extracellular matrix and proteases to modify that specific matrix.
A myocardial infarction induces tissue remodeling of the heart in a three-phase process: inflammation, proliferation, and maturation. Inflammation is characterized by massive necrosis in the infarcted area. Inflammatory cells clear the dead cells. In the proliferation phase, inflammatory cells die by apoptosis, being replaced by myofibroblasts which produce large amounts of collagen. In the maturation phase, myofibroblast numbers are reduced by apoptosis, allowing for infiltration by endothelial cells (for blood vessels) and cardiomyocytes (heart tissue cells). Usually, however, much of the tissue remodeling is pathological, resulting in a large amount of fibrous tissue. By contrast, aerobic exercise can produce beneficial cardiac tissue remodeling in those suffering from left ventricular hypertrophy.
Programmed cellular senescence contributes to beneficial tissue remodeling during embryonic development of the fetus.
In a brain stroke the penumbra area surrounding the ischemic event initially undergoes a damaging remodeling, but later transitions to a tissue remodeling characterized by repair.
Vascular remodeling refers to a compensatory change in blood vessel walls due to plaque growth. Vascular expansion is called positive remodeling, whereas vascular constriction is called negative remodeling.
Tissue remodeling occurs in adipose tissue with increased body fat. In obese subjects, this remodeling is often pathological, characterized by excessive inflammation and fibrosis. | 1 | Applied and Interdisciplinary Chemistry |
A common dynamic covalent building motif is bond formation between a carbon center and a heteroatom such as nitrogen or oxygen. Because the bond formed between carbon and a heteroatom is less stable than a carbon-carbon bond, they offer more reversibility and reach thermodynamic equilibrium faster than carbon bond forming dynamic covalent reactions. | 0 | Theoretical and Fundamental Chemistry |
PHBV was first manufactured in 1983 by Imperial Chemical Industries (ICI). It is commercialized under the trade name Biopol. ICI (Zeneca) sold it to Monsanto in 1996. This was then obtained by Metabolix in 2001. Biomer L is the trade name of PHBV from Biomer. | 1 | Applied and Interdisciplinary Chemistry |
RNA is notoriously unstable and vulnerable to ribonucleases, which has thus been an obstacle to the production and analysis of the cellular transcriptome. First referenced by Berger et al., the substance was used to prevent the digestion of RNA during isolation from white blood cells, and was rapidly adopted for such purposes as the acquisition of RNA from green beans. | 1 | Applied and Interdisciplinary Chemistry |
Most common imides are prepared by heating dicarboxylic acids or their anhydrides and ammonia or primary amines. The result is a condensation reaction:
: (RCO)O + R′NH → (RCO)NR′ + HO
These reactions proceed via the intermediacy of amides. The intramolecular reaction of a carboxylic acid with an amide is far faster than the intermolecular reaction, which is rarely observed.
They may also be produced via the oxidation of amides, particularly when starting from lactams.
: R(CO)NHCHR + 2 [O] → R(CO)N(CO)R + HO
Certain imides can also be prepared in the isoimide-to-imide Mumm rearrangement. | 0 | Theoretical and Fundamental Chemistry |
Hypothermia usually occurs from exposure to low temperatures, and is frequently complicated by alcohol consumption. Any condition that decreases heat production, increases heat loss, or impairs thermoregulation, however, may contribute. Thus, hypothermia risk factors include: substance use disorders (including alcohol use disorder), homelessness, any condition that affects judgment (such as hypoglycemia), the extremes of age, poor clothing, chronic medical conditions (such as hypothyroidism and sepsis), and living in a cold environment. Hypothermia occurs frequently in major trauma, and is also observed in severe cases of anorexia nervosa. Hypothermia is also associated with worse outcomes in people with sepsis. While most people with sepsis develop fevers (elevated body temperature), some develop hypothermia.
In urban areas, hypothermia frequently occurs with chronic cold exposure, such as in cases of homelessness, as well as with immersion accidents involving drugs, alcohol or mental illness. While studies have shown that people experiencing homelessness are at risk of premature death from hypothermia, the true incidence of hypothermia-related deaths in this population is difficult to determine. In more rural environments, the incidence of hypothermia is higher among people with significant comorbidities and less able to move independently. With rising interest in wilderness exploration, and outdoor and water sports, the incidence of hypothermia secondary to accidental exposure may become more frequent in the general population. | 1 | Applied and Interdisciplinary Chemistry |
Signal-correlation techniques were first experimentally applied to fluorescence in 1972 by Magde, Elson, and Webb, who are therefore commonly credited as the "inventors" of FCS. The technique was further developed in a group of papers by these and other authors soon after, establishing the theoretical foundations and types of applications.
Around 1990, with the ability of detecting sufficiently small number of fluorescence particles, two issues emerged: A non-Gaussian distribution of the fluorescence intensity and the three-dimensional confocal Measurement Volume of a laser-microscopy system. The former led to an analysis of distributions and moments of the fluorescent signals for extracting molecular information, which eventually became a collection of methods known as Brightness Analyses. See Thompson (1991) for a review of that period.
Beginning in 1993, a number of improvements in the measurement techniques—notably using confocal microscopy, and then two-photon microscopy—to better define the measurement volume and reject background—greatly improved the signal-to-noise ratio and allowed single molecule sensitivity. Since then, there has been a renewed interest in FCS, and as of August 2007 there have been over 3,000 papers using FCS found in Web of Science. See Krichevsky and Bonnet for a review. In addition, there has been a flurry of activity extending FCS in various ways, for instance to laser scanning and spinning-disk confocal microscopy (from a stationary, single point measurement), in using cross-correlation (FCCS) between two fluorescent channels instead of autocorrelation, and in using Förster Resonance Energy Transfer (FRET) instead of fluorescence. | 0 | Theoretical and Fundamental Chemistry |
Polymers are of great importance when considering protein adsorption in the biomedical arena. Polymers are composed of one or more types of "mers" bound together repeatedly, typically by directional covalent bonds. As the chain grows by the addition of mers, the chemical and physical properties of the material are dictated by the molecular structure of the monomer. By carefully selecting the type or types of mers in a polymer and its manufacturing process, the chemical and physical properties of a polymer can be highly tailored to adsorb specific proteins and cells for a particular application. | 1 | Applied and Interdisciplinary Chemistry |
A positioning goniometer or goniometric stage is a device that rotates an object precisely about a fixed axis in space. It is similar to a linear stage—however, rather than move linearly relative to its base, the stage platform rotates partially about a fixed axis above the mounting surface of the platform. Positioning goniometers typically use a worm drive with a partial worm wheel fixed to the underside of the stage platform meshing with a worm in the base. The worm gear may be rotated manually, or by a motor in automated positioning systems. | 0 | Theoretical and Fundamental Chemistry |
The solar flux absorbed by the planet from the star is equal to the flux emitted by the planet:
Assuming a fraction of the incident sunlight is reflected according to the planet's Bond albedo, :
where represents the area- and time-averaged incident solar flux, and may be expressed as:
The factor of 1/4 in the above formula comes from the fact that only a single hemisphere is lit at any moment in time (creates a factor of 1/2), and from integrating over angles of incident sunlight on the lit hemisphere (creating another factor of 1/2).
Assuming the planet radiates as a blackbody according to the Stefan–Boltzmann law at some equilibrium temperature , a balance of the absorbed and outgoing fluxes produces:
where is the Stefan-Boltzmann constant.
Rearranging the above equation to find the equilibrium temperature leads to: | 0 | Theoretical and Fundamental Chemistry |
Strong bases such as LiNR can be used to deprotonate imines and form metalloenamines. Metalloenamines can prove synthetically useful due to their nucleophilicity (they are more nucleophilic than enolates). Thus they are better able to react with weaker electrophiles (for example, they can be used to open epoxides.) Most prominently, these reactions have allowed for asymmetric alkylations of ketones through transformation to chiral intermediate metalloenamines. | 0 | Theoretical and Fundamental Chemistry |
Two rulers died from elixir poisoning during the Five Dynasties period (907–979) of political turmoil after the overthrow of the Tang dynasty. Zhu Wen or Emperor Taizu (r. 907–912), the founder of the Later Liang dynasty, became seriously incapacitated as a result of elixir poisoning, and fell victim to an assassination plot. Li Bian or Emperor Liezu (r. 937–943), the founder of the Southern Tang kingdom, took immortality elixirs that made him irritable and deathly ill.
The Daoist adept Chen Tuan (d. 989) advised two emperors that they should not worry about elixirs but direct their minds to improving the state administration, Chai Rong or Emperor Shizong of Later Zhou in 956, and then Emperor Taizu of Song in 976. | 1 | Applied and Interdisciplinary Chemistry |
Naphthenic hydrocarbons are saturated cyclic hydrocarbons, and are very important in the refining of liquid crude oil.
Also known as cyclic alkanes, they are represented by the formula CH, where n is a positive integer. | 0 | Theoretical and Fundamental Chemistry |
Blocked isocyanates are organic compounds that have their isocyanate functionality chemically blocked to control reactivity. They are the product of an isocyanate moiety (nearly always a di-isocyanate) and a suitable blocking agent. It may also be a polyurethane prepolymer that is NCO terminated but this functionality has also been chemically reacted with a blocking agent.
They are usually used in polyurethane applications but not always. They are extensively used in industrial applications such as coatings, sealants and adhesives. | 0 | Theoretical and Fundamental Chemistry |
Potentiometric sensors measure a potential or charge accumulation of an electrochemical cell. The transducer typically comprises an ion selective electrode (ISE) and a reference electrode. The ISE features a membrane that selectively interacts with the charged ion of interest, causing the accumulation of a charge potential compared to the reference electrode. The reference electrode provides a constant half-cell potential that is unaffected by analyte concentration. A high impedance voltmeter is used to measure the electromotive force or potential between the two electrodes when zero or no significant current flows between them. The potentiometric response is governed by the Nernst equation in that the potential is proportional to the logarithm of the concentration of the analyte. | 1 | Applied and Interdisciplinary Chemistry |
Nanoparticles can self-assemble as a result of their intermolecular forces. As systems look to minimize their free energy, self-assembly is one option for the system to achieve its lowest free energy thermodynamically. Nanoparticles can be programmed to self-assemble by changing the functionality of their side groups, taking advantage of weak and specific intermolecular forces to spontaneously order the particles. These direct interparticle interactions can be typical intermolecular forces such as hydrogen bonding or Van der Waals forces, but can also be internal characteristics, such as hydrophobicity or hydrophilicity. For example, lipophilic nanoparticles have the tendency to self-assemble and form crystals as solvents are evaporated. While these aggregations are based on intermolecular forces, external factors such as temperature and pH also play a role in spontaneous self-assembly. | 0 | Theoretical and Fundamental Chemistry |
In pre-modern medicine, the name diatragacanth was applied to certain powders that contain the natural gum tragacanth as its basis. There are two kinds: cold and hot.
Powder of cold diatragacanth is composed of the gums tragacanth and Arabic, liquorice, starch, white poppy seed, and the four great cold seeds (cucumber, gourd, watermelon, and melon). It was said to be good thicken, and soften the too sharp, and subtile serous humours occurring in the chest, to assuage coughs, and promote spitting.
Powder of hot diatragacanth is composed of gum tragacanth, cinnamon, hyssop, almonds, linseed, and fenugreek, liquorice, juice of liquorice, and ginger. It was said to be good against asthmas, to promote expectoration, strengthen the stomach, and assist in digestion. | 1 | Applied and Interdisciplinary Chemistry |
Somatic cells of different types can be fused to obtain hybrid cells. Hybrid cells are useful in a variety of ways, e.g.,
:(i) to study the control of cell division and gene expression,
:(ii) to investigate malignant transformations,
:(iii) to obtain viral replication,
:(iv) for gene or chromosome mapping and for
:(v) production of monoclonal antibodies by producing hybridoma (hybrid cells between an immortalised cell and an antibody producing lymphocyte), etc.
Chromosome mapping through somatic cell hybridization is essentially based on fusion of human and mouse somatic cells. Generally, human fibrocytes or leucocytes are fused with mouse continuous cell lines.
When human and mouse cells (or cells of any two mammalian species or of the same species) are mixed, spontaneous cell fusion occurs at a very low rate (10-6). Cell fusion is enhanced 100 to 1000 times by the addition of ultraviolet inactivated Sendai (parainfluenza) virus or polyethylene glycol (PEG).
These agents adhere to the plasma membranes of cells and alter their properties in such a way that facilitates their fusion. Fusion of two cells produces a heterokaryon, i.e., a single hybrid cell with two nuclei, one from each of the cells entering fusion. Subsequently, the two nuclei also fuse to yield a hybrid cell with a single nucleus.
A generalized scheme for somatic cell hybridization may be described as follows. Appropriate human and mouse cells are selected and mixed together in the presence of inactivated Sendai virus or PEG to promote cell fusion. After a period of time, the cells (a mixture of man, mouse and hybrid cells) are plated on a selective medium, e.g., HAT medium, which allows the multiplication of hybrid cells only.
Several clones (each derived from a single hybrid cell) of the hybrid cells are thus isolated and subjected to both cytogenetic and appropriate biochemical analyses for the detection of enzyme/ protein/trait under investigation. An attempt is now made to correlate the presence and absence of the trait with the presence and absence of a human chromosome in the hybrid clones.
If there is a perfect correlation between the presence and absence of a human chromosome and that of a trait in the hybrid clones, the gene governing the trait is taken to be located in the concerned chromosome.
The HAT medium is one of the several selective media used for the selection of hybrid cells. This medium is supplemented with hypoxanthine, aminopterin and thymidine, hence the name HAT medium. Antimetabolite aminopterin blocks the cellular biosynthesis of purines and pyrimidines from simple sugars and amino acids.
However, normal human and mouse cells can still multiply as they can utilize hypoxanthine and thymidine present in the medium through a salvage pathway, which ordinarily recycles the purines and pyrimidines produced from degradation of nucleic acids.
Hypoxanthine is converted into guanine by the enzyme hypoxanthine-guanine phosphoribosyltransferase (HGPRT), while thymidine is phosphorylated by thymidine kinase (TK); both HGPRT and TK are enzymes of the salvage pathway.
On a HAT medium, only those cells that have active HGPRT (HGPRT+) and TK (TK+) enzymes can proliferate, while those deficient in these enzymes (HGPRr- and/or TK-) can not divide (since they cannot produce purines and pyrimidines due to the aminopterin present in the HAT medium).
For using HAT medium as a selective agent, human cells used for fusion must be deficient for either the enzyme HGPRT or TK, while mouse cells must be deficient for the other enzyme of this pair. Thus, one may fuse HGPRT deficient human cells (designated as TK+ HGPRr-) with TK deficient mouse cells (denoted as TK- HGPRT+).
Their fusion products (hybrid cells) will be TK+ (due to the human gene) and HGPRT+ (due to the mouse gene) and will multiply on the HAT medium, while the man and mouse cells will fail to do so. Experiments with other selective media can be planned in a similar fashion. | 1 | Applied and Interdisciplinary Chemistry |
When a substrate binds to one enzymatic subunit, the rest of the subunits are stimulated and become active.
Ligands can either have positive cooperativity, negative cooperativity, or non-cooperativity.
An example of positive cooperativity is the binding of oxygen to hemoglobin. One oxygen molecule can bind to the ferrous iron of a heme molecule in each of the four chains of a hemoglobin molecule. Deoxy-hemoglobin has a relatively low affinity for oxygen, but when one molecule binds to a single heme, the oxygen affinity increases, allowing the second molecule to bind more easily, and the third and fourth even more easily. The oxygen affinity of 3-oxy-hemoglobin is ~300 times greater than that of deoxy-hemoglobin. This behavior leads the affinity curve of hemoglobin to be sigmoidal, rather than hyperbolic as with the monomeric myoglobin. By the same process, the ability for hemoglobin to lose oxygen increases as fewer oxygen molecules are bound. See also Oxygen-hemoglobin dissociation curve.
Negative cooperativity means that the opposite will be true; as ligands bind to the protein, the protein's affinity for the ligand will decrease, i.e. it becomes less likely for the ligand to bind to the protein. An example of this occurring is the relationship between glyceraldehyde-3-phosphate and the enzyme glyceraldehyde-3-phosphate dehydrogenase.
Homotropic cooperativity refers to the fact that the molecule causing the cooperativity is the one that will be affected by it. Heterotropic cooperativity is where a third party substance causes the change in affinity. Homotropic or heterotropic cooperativity could be of both positives as well as negative types depend upon whether it support or oppose further binding of the ligand molecules to the enzymes. | 1 | Applied and Interdisciplinary Chemistry |
Carotenoids () are yellow, orange, and red organic pigments that are produced by plants and algae, as well as several bacteria, archaea, and fungi. Carotenoids give the characteristic color to pumpkins, carrots, parsnips, corn, tomatoes, canaries, flamingos, salmon, lobster, shrimp, and daffodils. Over 1,100 identified carotenoids can be further categorized into two classes xanthophylls (which contain oxygen) and carotenes (which are purely hydrocarbons and contain no oxygen).
All are derivatives of tetraterpenes, meaning that they are produced from 8 isoprene units and contain 40 carbon atoms. In general, carotenoids absorb wavelengths ranging from 400 to 550 nanometers (violet to green light). This causes the compounds to be deeply colored yellow, orange, or red. Carotenoids are the dominant pigment in autumn leaf coloration of about 15-30% of tree species, but many plant colors, especially reds and purples, are due to polyphenols.
Carotenoids serve two key roles in plants and algae: they absorb light energy for use in photosynthesis, and they provide photoprotection via non-photochemical quenching. Carotenoids that contain unsubstituted beta-ionone rings (including β-carotene, α-carotene, β-cryptoxanthin, and γ-carotene) have vitamin A activity (meaning that they can be converted to retinol). In the eye, lutein, meso-zeaxanthin, and zeaxanthin are present as macular pigments whose importance in visual function, as of 2016, remains under clinical research. | 0 | Theoretical and Fundamental Chemistry |
Borane tert-butylamine is an amine borane complex derived from tert-butylamine and borane. It is a colorless solid.
The compound is prepared by the reaction of tert-butylammonium chloride and sodium borohydride:
:t-BuNHCl + NaBH → t-BuNHBH + H + NaCl
In organic synthesis, borane tert-butylamine can be used for selective reduction of certain functional groups including aldehydes, ketones, oximes, and imines.
In photographic processing, it is used in the E-4 process, as "chemical enlighting" step in the processing of the film. | 0 | Theoretical and Fundamental Chemistry |
The term radical was already in use when radical theory was developed. Louis-Bernard Guyton de Morveau introduced the phrase "radical" in 1785 and the phrase was employed by Antoine Lavoisier in 1789 in his Traité Élémentaire de Chimie. A radical was identified as the root base of certain acids (The Latin word "radix" meaning "root"). The combination of a radical with oxygen would result in an acid. For example the radical of acetic acid was called "acetic" and that of muriatic acid (hydrochloric acid) was called "muriatic". Joseph Louis Gay-Lussac found evidence for the cyanide radical in 1815 in his work on hydrogen cyanide and a number of cyanide salts he discovered. He also isolated cyanogen ((CN)) not realizing that cyanogen is the cyanide dimer NC-CN. Jean-Baptiste Dumas proposed the ethylene radical from investigations into diethyl ether and ethanol. In his Etherin theory he observed that ether consisted of two equivalents of ethylene and one equivalent of water and that ethylene and ethanol could interconvert in chemical reactions. Ethylene was also the base fragment for a number of other compounds such as ethyl acetate. This Etherin theory was eventually abandoned by Dumas in favor of radical theory. As a radical it should react with an oxide to form the hydrate but it was found that ethylene is resistant to an oxide like calcium oxide. Henri Victor Regnault in 1834 reacted ethylene dichloride (CHCH.Cl) with KOH forming vinyl chloride, water, and KCl. In etherin theory it should not be possible to break up the ethylene fragment in this way.
Radical theory replaced electrochemical dualism which stated that all molecules were to be considered as salts composed of basic and acidic oxides. | 0 | Theoretical and Fundamental Chemistry |
Some experimental work towards developing quantum computers use trapped ions. Units of quantum information called qubits are stored in stable electronic states of each ion, and quantum information can be processed and transferred through the collective quantized motion of the ions, interacting by the Coulomb force. Lasers are applied to induce coupling between the qubit states (for single qubit operations) or between the internal qubit states and external motional states (for entanglement between qubits). | 0 | Theoretical and Fundamental Chemistry |
The Stokes number (Stk), named after George Gabriel Stokes, is a dimensionless number characterising the behavior of particles suspended in a fluid flow. The Stokes number is defined as the ratio of the characteristic time of a particle (or droplet) to a characteristic time of the flow or of an obstacle, or
where is the relaxation time of the particle (the time constant in the exponential decay of the particle velocity due to drag), is the fluid velocity of the flow well away from the obstacle, and is the characteristic dimension of the obstacle (typically its diameter) or a characteristic length scale in the flow (like boundary layer thickness). A particle with a low Stokes number follows fluid streamlines (perfect advection), while a particle with a large Stokes number is dominated by its inertia and continues along its initial trajectory.
In the case of Stokes flow, which is when the particle (or droplet) Reynolds number is less than about one, the particle drag coefficient is inversely proportional to the Reynolds number itself. In that case, the characteristic time of the particle can be written as
where is the particle density, is the particle diameter and is the fluid dynamic viscosity.
In experimental fluid dynamics, the Stokes number is a measure of flow tracer fidelity in particle image velocimetry (PIV) experiments where very small particles are entrained in turbulent flows and optically observed to determine the speed and direction of fluid movement (also known as the velocity field of the fluid). For acceptable tracing accuracy, the particle response time should be faster than the smallest time scale of the flow. Smaller Stokes numbers represent better tracing accuracy; for , particles will detach from a flow especially where the flow decelerates abruptly. For , particles follow fluid streamlines closely. If , tracing accuracy errors are below 1%. | 1 | Applied and Interdisciplinary Chemistry |
The utility of PCBs is based largely on their chemical stability, including low flammability and high dielectric constant. In an electric arc, PCBs generate incombustible gases.
Use of PCBs is commonly divided into closed and open applications. Examples of closed applications include coolants and insulating fluids (transformer oil) for transformers and capacitors, such as those used in old fluorescent light ballasts, hydraulic fluids, lubricating and cutting oils, and the like. In contrast, the major open application of PCBs was in carbonless copy ("NCR") paper, which even presently results in paper contamination.
Other open applications were as plasticizers in paints and cements, stabilizing additives in flexible PVC coatings of electrical cables and electronic components, pesticide extenders, reactive flame retardants and sealants for caulking, adhesives, wood floor finishes, such as Fabulon and other products of Halowax in the U.S., de-dusting agents, waterproofing compounds, casting agents. It was also used as a plasticizer in paints and especially "coal tars" that were used widely to coat water tanks, bridges and other infrastructure pieces.
Modern sources include pigments, which may be used in inks for paper or plastic products. PCBs are also still found in old equipment like capacitors, ballasts, X-ray machine, and other e-waste. | 1 | Applied and Interdisciplinary Chemistry |
L-(+)-tartaric acid, can participate in several reactions. As shown the reaction scheme below, dihydroxymaleic acid is produced upon treatment of L-(+)-tartaric acid with hydrogen peroxide in the presence of a ferrous salt.
:HOCCH(OH)CH(OH)COH + HO → HOCC(OH)C(OH)COH + 2 HO
Dihydroxymaleic acid can then be oxidized to tartronic acid with nitric acid. | 0 | Theoretical and Fundamental Chemistry |
Scientists at Duke University in the U.S. have developed and are testing a pilot fecal sludge treatment unit that fits in a 20-foot shipping container and treats the fecal matter of roughly 1000 people using a new supercritical water oxidation (SCWO) process. The SCWO technology can covert any type of organic waste (fecal, food waste, paper, plastic, etc.) to energy and clean water.
The waste (sludge) is reacted with air at temperatures and pressures above the critical point of water (374 °C, 221 Bar) to convert all of the organics into clean water and CO in seconds. Byproducts include distilled water, clean water which contains suspended inorganic minerals that can be utilized as fertilizers. The unit generates more than 900 liters of water for each ton of processed waste and the water can be processed further to drinking water.
The continuous process utilizes the energy embedded in the waste, thus enabling operating off-the-grid. 374Water is a Duke University spin-off company aiming to commercialize the SCWO technology. | 1 | Applied and Interdisciplinary Chemistry |
Signaling Gateway is a web portal dedicated to signaling pathways powered by the San Diego Supercomputer Center at the University of California, San Diego. It was initiated by a collaboration between the Alliance for Cellular Signaling and Nature. A primary feature is the Molecule Pages database. | 1 | Applied and Interdisciplinary Chemistry |
Farther from the sun, the temperature was low enough that volatile elements would precipitate as ices. The two are separated by a snow line controlled by the temperature distribution around the Sun.
Formed farthest from the sun, the carbonaceous chondrites have the highest K/U ratios. Ordinary chondrites which form closer in are only about 10% depleted in K relative to U.
The fine-grained matrix which fills spaces between the chondrules, however, appears to have formed at rather different temperatures in the various classes of chondrites. For this reason the volatile abundances of different classes of chondrites can vary. One particularly important class is the carbonaceous chondrites because of their high carbon content. In these meteorites, chondrules coexist with minerals that are only stable below 100 °C, so they contain materials that formed in both high- and low-temperature environments and were only later collected together. Further evidence for the primordial attributes of carbonaceous chondrites comes from the fact that they have compositions very similar to the nonvolatile element composition of the sun. | 0 | Theoretical and Fundamental Chemistry |
Amoxicillin (α-amino-p-hydroxybenzyl penicillin) is a semisynthetic derivative of penicillin with a structure similar to ampicillin but with better absorption when taken by mouth, thus yielding higher concentrations in blood and in urine. Amoxicillin diffuses easily into tissues and body fluids. It will cross the placenta and is excreted into breastmilk in small quantities. It is metabolized by the liver and excreted into the urine. It has an onset of 30 minutes and a half-life of 3.7 hours in newborns and 1.4 hours in adults.
Amoxicillin attaches to the cell wall of susceptible bacteria and results in their death. It is effective against streptococci, pneumococci, enterococci, Haemophilus influenzae, Escherichia coli, Proteus mirabilis, Neisseria meningitidis, Neisseria gonorrhoeae, Shigella, Chlamydia trachomatis, Salmonella, Borrelia burgdorferi, and Helicobacter pylori. As a derivative of ampicillin, amoxicillin is a member of the penicillin family and, like penicillins, is a β-lactam antibiotic. It inhibits cross-linkage between the linear peptidoglycan polymer chains that make up a major component of the bacterial cell wall.
It has two ionizable groups in the physiological range (the amino group in alpha-position to the amide carbonyl group and the carboxyl group). | 0 | Theoretical and Fundamental Chemistry |
Friction loss, which is due to the shear stress between the pipe surface and the fluid flowing within, depends on the conditions of flow and the physical properties of the system. These conditions can be encapsulated into a dimensionless number Re, known as the Reynolds number
where V is the mean fluid velocity and D the diameter of the (cylindrical) pipe. In this expression, the properties of the fluid itself are reduced to the kinematic viscosity ν
where
: μ = viscosity of the fluid (SI kg / m • s) | 1 | Applied and Interdisciplinary Chemistry |
Anaerobic microbial mineralization of recalcitrant organic pollutants is of great environmental significance and involves intriguing novel biochemical reactions. In particular, hydrocarbons and halogenated compounds have long been doubted to be degradable in the absence of oxygen, but the isolation of hitherto unknown anaerobic hydrocarbon-degrading and reductively dehalogenating bacteria during the last decades provided ultimate proof for these processes in nature. While such research involved mostly chlorinated compounds initially, recent studies have revealed reductive dehalogenation of bromine and iodine moieties in aromatic pesticides. Other reactions, such as biologically induced abiotic reduction by soil minerals, has been shown to deactivate relatively persistent aniline-based herbicides far more rapidly than observed in aerobic environments. Many novel biochemical reactions were discovered enabling the respective metabolic pathways, but progress in the molecular understanding of these bacteria was rather slow, since genetic systems are not readily applicable for most of them. However, with the increasing application of genomics in the field of environmental microbiology, a new and promising perspective is now at hand to obtain molecular insights into these new metabolic properties. Several complete genome sequences were determined during the last few years from bacteria capable of anaerobic organic pollutant degradation. The ~4.7 Mb genome of the facultative denitrifying Aromatoleum aromaticum strain EbN1 was the first to be determined for an anaerobic hydrocarbon degrader (using toluene or ethylbenzene as substrates). The genome sequence revealed about two dozen gene clusters (including several paralogs) coding for a complex catabolic network for anaerobic and aerobic degradation of aromatic compounds. The genome sequence forms the basis for current detailed studies on regulation of pathways and enzyme structures. Further genomes of anaerobic hydrocarbon degrading bacteria were recently completed for the iron-reducing species Geobacter metallireducens (accession nr. NC_007517) and the perchlorate-reducing Dechloromonas aromatica (accession nr. NC_007298), but these are not yet evaluated in formal publications. Complete genomes were also determined for bacteria capable of anaerobic degradation of halogenated hydrocarbons by halorespiration: the ~1.4 Mb genomes of Dehalococcoides ethenogenes strain 195 and Dehalococcoides sp. strain CBDB1 and the ~5.7 Mb genome of Desulfitobacterium hafniense strain Y51. Characteristic for all these bacteria is the presence of multiple paralogous genes for reductive dehalogenases, implicating a wider dehalogenating spectrum of the organisms than previously known. Moreover, genome sequences provided unprecedented insights into the evolution of reductive dehalogenation and differing strategies for niche adaptation.
Recently, it has become apparent that some organisms, including Desulfitobacterium chlororespirans, originally evaluated for halorespiration on chlorophenols, can also use certain brominated compounds, such as the herbicide bromoxynil and its major metabolite as electron acceptors for growth. Iodinated compounds may be dehalogenated as well, though the process may not satisfy the need for an electron acceptor. | 1 | Applied and Interdisciplinary Chemistry |
Crucible is used in the laboratory to contain chemical compounds when heated to extremely high temperatures. Crucibles are available in several sizes and typically come with a correspondingly-sized lid. When heated over a flame, the crucible is often held inside a pipeclay triangle which itself is held on top of a tripod.
Crucibles and their covers are made of high temperature-resistant materials, usually porcelain, alumina or an inert metal. One of the earliest uses of platinum was to make crucibles. Ceramics such as alumina, zirconia, and especially magnesia will tolerate the highest temperatures. More recently, metals such as nickel and zirconium have been used. The lids are typically loose-fitting to allow gases to escape during the heating of a sample inside. Crucibles and their lids can come in high form and low form shapes and in various sizes, but rather small 10 to 15 ml size porcelain crucibles are commonly used for gravimetric chemical analysis. These small-size crucibles and their covers made of porcelain are quite cheap when sold in quantity to laboratories, and the crucibles are sometimes disposed of after use in precise quantitative chemical analysis. There is usually a large mark-up when they are sold individually in hobby shops.
In the area of chemical analysis, crucibles are used in quantitative gravimetric chemical analysis (analysis by measuring mass of an analyte or its derivative). Common crucible use may be as follows. A residue or precipitate in a chemical analysis method can be collected or filtered from some sample or solution on special "ashless" filter paper. The crucible and lid to be used are pre-weighed very accurately on an analytical balance. After some possible washing and/or pre-drying of this filtrate, the residue on the filter paper can be placed in the crucible and fired (heated at very high temperature) until all the volatiles and moisture are driven out of the sample residue in the crucible. The "ashless" filter paper is completely burned up in this process. The crucible with the sample and lid is allowed to cool in a desiccator. The crucible and lid with the sample inside are weighed very accurately again only after it has completely cooled to room temperature (higher temperature would cause air currents around the balance giving inaccurate results). The mass of the empty, pre-weighed crucible and lid is subtracted from this result to yield the mass of the completely dried residue in the crucible.
A crucible with a bottom perforated with small holes which are designed specifically for use in filtration, especially for gravimetric analysis as just described, is called a Gooch crucible after its inventor, Frank Austin Gooch.
For completely accurate results, the crucible is handled with clean tongs because fingerprints can add a weighable mass to the crucible. Porcelain crucibles are hygroscopic, i. e. they absorb a bit of weighable moisture from the air. For this reason, the porcelain crucible and lid is also pre-fired (pre-heating to high temperature) to constant mass before the pre-weighing. This determines the mass of the completely dry crucible and lid. At least two firings, coolings, and weighings resulting in exactly the same mass are needed to confirm the constant (completely dry) mass of the crucible and lid and similarly again for the crucible, lid, and sample residue inside. Since the mass of every crucible and lid is different, the pre-firing/pre-weighing must be done for every new crucible/lid used. The desiccator contains desiccant to absorb moisture from the air inside, so the air inside will be completely dry. | 0 | Theoretical and Fundamental Chemistry |
Ninhydrin may cause allergic, IgE-mediated rhinitis and asthma. A case has been described in which a 41 year old forensic laboratory worker working with Ninhydrin developed rhinitis and respiratory difficulty. Her specific IgE levels were found almost doubled. | 0 | Theoretical and Fundamental Chemistry |
Cell biology research looks at different ways to culture and manipulate cells outside of a living body to further research in human anatomy and physiology, and to derive medications.The techniques by which cells are studied have evolved. Due to advancements in microscopy, techniques and technology have allowed scientists to hold a better understanding of the structure and function of cells. Many techniques commonly used to study cell biology are listed below:
* Cell culture: Utilizes rapidly growing cells on media which allows for a large amount of a specific cell type and an efficient way to study cells. Cell culture is one of the major tools used in cellular and molecular biology, providing excellent model systems for studying the normal physiology and biochemistry of cells (e.g., metabolic studies, aging), the effects of drugs and toxic compounds on the cells, and mutagenesis and carcinogenesis. It is also used in drug screening and development, and large scale manufacturing of biological compounds (e.g., vaccines, therapeutic proteins).
* Fluorescence microscopy: Fluorescent markers such as GFP, are used to label a specific component of the cell. Afterwards, a certain light wavelength is used to excite the fluorescent marker which can then be visualized.
* Phase-contrast microscopy: Uses the optical aspect of light to represent the solid, liquid, and gas-phase changes as brightness differences.
* Confocal microscopy: Combines fluorescence microscopy with imaging by focusing light and snap shooting instances to form a 3-D image.
* Transmission electron microscopy: Involves metal staining and the passing of electrons through the cells, which will be deflected upon interaction with metal. This ultimately forms an image of the components being studied.
* Cytometry: The cells are placed in the machine which uses a beam to scatter the cells based on different aspects and can therefore separate them based on size and content. Cells may also be tagged with GFP-fluorescence and can be separated that way as well.
* Cell fractionation: This process requires breaking up the cell using high temperature or sonification followed by centrifugation to separate the parts of the cell allowing for them to be studied separately. | 1 | Applied and Interdisciplinary Chemistry |
Serghidess solution is used to solve directly for the Darcy–Weisbach friction factor f for a full-flowing circular pipe. It is an approximation of the implicit Colebrook–White equation. It was derived using Steffensens method.
The solution involves calculating three intermediate values and then substituting those values into a final equation.
The equation was found to match the Colebrook–White equation within 0.0023% for a test set with a 70-point matrix consisting of ten relative roughness values (in the range 0.00004 to 0.05) by seven Reynolds numbers (2500 to 10). | 1 | Applied and Interdisciplinary Chemistry |
The operating principle of CCC equipment requires a column consisting of a tube coiled around a bobbin. The bobbin is rotated in a double-axis gyratory motion (a cardioid), which causes a variable g-force to act on the column during each rotation. This motion causes the column to see one partitioning step per revolution and components of the sample separate in the column due to their partitioning coefficient between the two immiscible liquid phases. "High-performance" countercurrent chromatography (HPCCC) works in much the same way as HSCCC. A seven-year research and development process produced HPCCC instruments that generated 240 gs, compared to the 80 gs of the HSCCC machines. This increase in g-force and larger bore of the column has enabled a ten-fold increase in throughput, due to improved mobile phase flow rates and a higher stationary phase retention. Countercurrent chromatography is a preparative liquid chromatography technique, however with the advent of the higher-g HPCCC instruments it is now possible to operate instruments with sample loadings as low as a few milligrams, whereas in the past hundreds of milligrams had been necessary. Major application areas for this technique include natural product purification and drug development. | 0 | Theoretical and Fundamental Chemistry |
Methods of delivering UCP1 to cells by gene transfer therapy or methods of its upregulation have been an important line of enquiry in research into the treatment of obesity, due to their ability to dissipate excess metabolic stores. | 1 | Applied and Interdisciplinary Chemistry |
Fusion takes place when atoms come into close proximity and the nuclear force pulls their nuclei together to form a single larger nucleus. Counteracting this process is the positive charge of the nuclei, which repel each other due to the electrostatic force. For fusion to occur, the nuclei must have enough energy to overcome this coulomb barrier. The barrier is lower for atoms with less positive charge: those with the fewest protons. The nuclear force increases with more nucleons: the total number of protons and neutrons. This means that a combination of deuterium and tritium has the lowest coulomb barrier, at about 100 keV (see requirements for fusion).
When the fuel is heated to high energies the electrons disassociate from the nuclei, which are left as individual ions and electrons mixed in a gas-like plasma. Particles in a gas are distributed across a wide range of energies in a spectrum known as the Maxwell–Boltzmann distribution. At any given temperature the majority of the particles are at lower energies, with a "long tail" containing smaller numbers of particles at much higher energies. So while 100 keV represents a temperature of over one billion degrees, to produce fusion events, the fuel does not need to be heated to this temperature as a whole: some reactions will occur even at lower temperatures due to the small number of high-energy particles in the mix.
As the fusion reactions give off large amounts of energy, and some of that energy will be deposited back in the fuel, these reactions heat the fuel. There is a critical temperature at which the rate of reactions, and thus the energy deposited, balances losses to the environment. At this point the reaction becomes self-sustaining, a point known as ignition. For D-T fuel, that temperature is between 50 and 100 million degrees. The overall rate of fusion and net energy release is dependent on the combination of temperature, density and energy confinement time, known as the fusion triple product.
Two primary approaches have developed to attack the fusion power problem. In the inertial confinement approach, the fuel is quickly squeezed to extremely high densities, which also increases the internal temperature through the adiabatic process. There is no attempt to maintain these conditions for any period of time, the fuel explodes outward as soon as the force is released. The confinement time is on the order of microseconds, so the temperatures and density must be very high for any appreciable amount of the fuel to undergo fusion. This approach has been successful in producing fusion reactions, but to date, the devices that can provide the compression, typically lasers, require far more energy than the reactions produce.
The more widely studied approach is magnetic confinement. Since the plasma is electrically charged, it will follow magnetic lines of force and a suitable arrangement of fields can keep the fuel away from the container walls. The fuel is then heated over an extended period until some of the fuel in the tail starts undergoing fusion. At the temperatures and densities that are possible using magnets the fusion process is fairly slow, so this approach requires long confinement times on the order of tens of seconds, or minutes. Confining a gas at millions of degrees for this sort of time scale has proven difficult, although modern experimental machines are approaching the conditions needed for net power production, or "breakeven". | 0 | Theoretical and Fundamental Chemistry |
TsOH is prepared on an industrial scale by the sulfonation of toluene. Common impurities include benzenesulfonic acid and sulfuric acid. TsOH monohydrate contains an amount of water. To estimate the total moisture present as impurity, the Karl Fischer method is used. Impurities can be removed by recrystallization from its concentrated aqueous solution followed by azeotropic drying with toluene.
TsOH finds use in organic synthesis as an "organic-soluble" strong acid. Examples of uses include:
*Acetalization of an aldehyde.
*Fischer–Speier esterification
*Transesterification reactions | 0 | Theoretical and Fundamental Chemistry |
In a solid, there is a non-zero stiffness both for volumetric deformations and shear deformations. Hence, it is possible to generate sound waves with different velocities dependent
on the deformation mode. Sound waves generating volumetric deformations (compression) and shear deformations (shearing) are called pressure waves (longitudinal waves) and shear waves (transverse waves), respectively. In earthquakes, the corresponding seismic waves are called P-waves (primary waves) and S-waves (secondary waves), respectively. The sound velocities of these two types of waves propagating in a homogeneous 3-dimensional solid are respectively given by
where
* K is the bulk modulus of the elastic materials;
* G is the shear modulus of the elastic materials;
* E is the Young's modulus;
* ρ is the density;
* ν is Poisson's ratio.
The last quantity is not an independent one, as . Note that the speed of pressure waves depends both on the pressure and shear resistance properties of the material, while the speed of shear waves depends on the shear properties only.
Typically, pressure waves travel faster in materials than do shear waves, and in earthquakes this is the reason that the onset of an earthquake is often preceded by a quick upward-downward shock, before arrival of waves that produce a side-to-side motion. For example, for a typical steel alloy, , and , yielding a compressional speed c of . This is in reasonable agreement with c measured experimentally at for a (possibly different) type of steel. The shear speed c is estimated at using the same numbers.
Speed of sound in semiconductor solids can be very sensitive to the amount of electronic dopant in them. | 1 | Applied and Interdisciplinary Chemistry |
AutoAnalyzers are still used for a few clinical applications such as neonatal screening or Anti-D, but the majority of instruments are now used for industrial and environmental work. Standardized methods have been published by the ASTM (ASTM International), the US Environmental Protection Agency (EPA) as well as the International Organization for Standardization (ISO) for environmental analytes such as nitrite, nitrate, ammonia, cyanide, and phenol. Autoanalyzers are also commonly used in soil testing laboratories, fertilizer analysis, process control, seawater analysis, air contaminants, and tobacco leaf analysis. | 0 | Theoretical and Fundamental Chemistry |
Compounds containing the tetrathionate anion include sodium tetrathionate, NaSO, potassium tetrathionate, KSO, and barium tetrathionate dihydrate, BaSO·2HO. | 1 | Applied and Interdisciplinary Chemistry |
On 18 September 1856, a year after he arrived from Scotland, he married Elizabeth Clark in Melbourne, Australia. She had arrived three days before the wedding with her maid on the Admiral, the same ship on which he had travelled out a year earlier, which reached Hobsons Bay (Melbournes port) on 15 September 1856, having set sail from London on 7 June 1856. Elizabeth Clark was probably born on 7 October 1832 in Barony parish Scotland, near Glasgow (her mother being Mary McGregor). She was the second daughter of John Clark, of Levenfield House in Alexandria, the Vale of Leven, a short distance north of Glasgow in West Dunbartonshire. His Levenfield Works were involved in similar work to Dr John Macadams father William Macadam in Kilmarnock in the then lucrative business of textile printing for domestic and European markets. The Clarks and Macadams must have become known to each other in Scotland because of their respective fathers business connections. Elizabeth died in 1915, in Brighton, Victoria.
John and Elizabeth had two sons:
John Melnotte Macadam was born 29 August 1858 at Fitzroy, Melbourne, Australia, and died on 30 January 1859, aged 5 months (he was reburied with his father, whose monument bears the additional inscription: In memory of his only children John Melnotte Macadam Born August 29, 1858 Died January 30, 1859 followed by an inscription to his second son below it).
William Castlemaine Macadam was born on 2 July 1860 and died 17 December 1865 at Williamstown, Victoria, Australia. He died aged five and had survived his father by a few months. The inscription on his fathers burial monument under His only children has him listed under his elder brother (above), who died in infancy, but does not for some reason give Williams date of death on it. | 0 | Theoretical and Fundamental Chemistry |
Phoslock is the commercial name for a bentonite clay in which the sodium and/or calcium ions are exchanged for lanthanum. The lanthanum contained within Phoslock reacts with phosphate to form an inert mineral known as rhabdophane (). Phoslock is used in lake restoration projects to remove excess phosphorus from aquatic systems, thereby improving water quality and inducing biological recovery in impaired freshwater systems.
It was developed in Australia by the CSIRO in the late 1990s by Dr Grant Douglas (US Patent 6350383) as a way of utilising the ability of lanthanum to bind phosphate in freshwater natural aquatic systems. The first large-scale trial took place in January 2000 in the Canning River, Western Australia.
During its development, patenting and commercialisation by CSIRO and subsequent commercial production, Phoslock has been a subject in academic research and has been used globally in lake restoration projects. The largest number of whole lake applications and the most comprehensive pre- and post-application monitoring has taken place in Europe, primarily Germany (where it is sold under the tradename Bentophos), the Netherlands and the UK.
There are studies indicating that lanthanum release due to application of this clay could lead to increased concentrations of this rare element in water and soils, resulting in bioaccumulation in animal tissues and there are still concerns and precautions to be taken as currently there is not enough complete and independent information. | 1 | Applied and Interdisciplinary Chemistry |
The valence OSLOs of the molecule can also be constructed using the method. The oxidation state of the ligand and metal are also determined and show consistency with the expected Lewis structure and can provide great insight for evaluating the redox reactivity.
last FOLI and Δ-FOLI are two important values to evaluate the quality of the localization result. With the last FOLI closer to 1, it means that the OSLOs are highly localized on one fragment. On the other hand, Δ-FOLI is the difference between the last FOLI and the second-last FOLI. With a larger Δ-FOLI, it means the selected set of OSLOs is much better than other options, which indicates the unambiguity of this result. | 0 | Theoretical and Fundamental Chemistry |
Nuclei with zero-spin and high excitation energies (more than about 1.022 MeV) also can't rid themselves of energy by (single) gamma emission due to the constraint imposed by conservation of momentum, but they do have enough decay energy to decay by pair production. In this type of decay, an electron and positron are both emitted from the atom at the same time, and conservation of angular momentum is solved by having these two product particles spin in opposite directions.
IC should not be confused with the similar photoelectric effect. When a gamma ray emitted by the nucleus of an atom hits another atom, it may be absorbed producing a photoelectron of well-defined energy (this used to be called "external conversion"). In IC, however, the process happens within one atom, and without a real intermediate gamma ray.
Just as an atom may produce an IC electron in place of a gamma ray if energy is available from within the nucleus, so an atom may produce an Auger electron in place of an X-ray if an electron is missing from one of the low-lying electron shells. (The first process can even precipitate the second one.) Like IC electrons, Auger electrons have a discrete energy, resulting in a sharp energy peak in the spectrum.
Electron capture also involves an inner shell electron, which in this case is retained in the nucleus (changing the atomic number) and leaving the atom (not nucleus) in an excited state. The atom missing an inner electron can relax by a cascade of X-ray emissions as higher energy electrons in the atom fall to fill the vacancy left in the electron cloud by the captured electron. Such atoms also typically exhibit Auger electron emission. Electron capture, like beta decay, also typically results in excited atomic nuclei, which may then relax to a state of lowest nuclear energy by any of the methods permitted by spin constraints, including gamma decay and internal conversion decay. | 0 | Theoretical and Fundamental Chemistry |
In phase-II metabolizing includes glucuronidation and sulfation of the mycoestrogen compound. Glucuronidation is the major phase II metabolic pathway. The transferase UGT (5-diphosphate glucuronosyltransferase) adds a glucuronic acid group sourced from uridine 5-diphosphate glucuronic acid (UDPGA). | 1 | Applied and Interdisciplinary Chemistry |
Like phosphine itself, but easier, organophosphines undergo protonation. The reaction is reversible. Whereas organophosphines are oxygen-sensitive, the protonated derivatives are not.
Primary and secondary derivatives, they can be deprotonated by strong bases to give organophosphide derivatives. Thus diphenylphosphine reacts with organolithium reagent to give lithium diphenylphosphide:
:HPPh + RLi → LiPPh + RH | 0 | Theoretical and Fundamental Chemistry |
1-(4-Chlorophenyl)silatrane is a GABA receptor antagonist and it destroys nervous functions in the central nervous system of vertebrates, primarily in the brain and possibly in the brain stem. It's a rapid acting convulsant, causing convulsions within 1 minute in mice and rats. Death occurred within 5 minutes. It is therefore likely to induce poison shyness. In field trials, it was less effective than zinc phosphide against wild rats. | 1 | Applied and Interdisciplinary Chemistry |
A primary flow element is a device inserted into the flowing fluid that produces a physical property that can be accurately related to flow. For example, an orifice plate produces a pressure drop that is a function of the square of the volume rate of flow through the orifice. A vortex meter primary flow element produces a series of oscillations of pressure. Generally, the physical property generated by the primary flow element is more convenient to measure than the flow itself. The properties of the primary flow element, and the fidelity of the practical installation to the assumptions made in calibration, are critical factors in the accuracy of the flow measurement. | 1 | Applied and Interdisciplinary Chemistry |
Compound collagen-based scaffolds have been developed in an attempt to improve the function of these scaffolds for tissue engineering. An example of a compound collagen scaffold is the collagen-chitosan matrix. Chitosan is a polysaccharide that is chemically similar to cellulose. Unlike collagen, chitosan biodegrades relatively slowly. However, chitosan is not very biocompatible with fibroblasts. To improve the stability of scaffolds containing gelatin or collagen and the biocompatibility of chitosan is made by crosslinking the two; they compensate for each other's shortcomings.
Collagen-elastine membrane, collagen-glycosaminoglycane (C-GAG) matrix, cross-linked collagen matrix Integra and Terudermis are other examples of compound collagen scaffolds.
Allogeneic cultured keratinocytes and fibroblasts in bovine collagen (Gintuit) is the first cell-based product made from allogeneic human cells and bovine collagen approved by the US Food and Drug Administration (FDA). It is an allogeneic cellularized scaffold product and was approved for medical use in the United States in March 2012. | 1 | Applied and Interdisciplinary Chemistry |
Viral protein interactomes consist of interactions among viral or phage proteins. They were among the first interactome projects as their genomes are small and all proteins can be analyzed with limited resources. Viral interactomes are connected to their host interactomes, forming virus-host interaction networks. Some published virus interactomes include
Bacteriophage
* Escherichia coli bacteriophage lambda
* Escherichia coli bacteriophage T7
* Streptococcus pneumoniae bacteriophage Dp-1
* Streptococcus pneumoniae bacteriophage Cp-1
The lambda and VZV interactomes are not only relevant for the biology of these viruses but also for technical reasons: they were the first interactomes that were mapped with multiple Y2H vectors, proving an improved strategy to investigate interactomes more completely than previous attempts have shown.
Human (mammalian) viruses
* Human varicella zoster virus (VZV)
* Chandipura virus
* Epstein-Barr virus (EBV)
* Hepatitis C virus (HPC), Human-HCV interactions
* Hepatitis E virus (HEV)
* Herpes simplex virus 1 (HSV-1)
* Kaposi's sarcoma-associated herpesvirus (KSHV)
* Murine cytomegalovirus (mCMV) | 1 | Applied and Interdisciplinary Chemistry |
The collision/reaction cell is used to remove interfering ions through ion/neutral reactions. Collision/reaction cells are known under several names. The dynamic reaction cell is located before the quadrupole in the ICP-MS device. The chamber has a quadrupole and can be filled with reaction (or collision) gases (ammonia, methane, oxygen or hydrogen), with one gas type at a time or a mixture of two of them, which reacts with the introduced sample, eliminating some of the interference.
The integrated Collisional Reaction Cell (iCRC) used by Analytik Jena ICP-MS is a mini-collision cell installed in front of the parabolic ion mirror optics that removes interfering ions by injecting a collisional gas (He), or a reactive gas (H), or a mixture of the two, directly into the plasma as it flows through the skimmer cone and/or the sampler cone. The iCRC removed interfering ions using a collisional kinetic energy discrimination (KED) phenomenon and chemical reactions with interfering ions similarly to traditionally used larger collision cells. | 0 | Theoretical and Fundamental Chemistry |
Traditionally Grignard reagents are prepared by treating an organic halide (normally organobromine) with magnesium metal. Ethers are required to stabilize the organomagnesium compound. Water and air, which rapidly destroy the reagent by protonolysis or oxidation, are excluded. Although the reagents still need to be dry, ultrasound can allow Grignard reagents to form in wet solvents by activating the magnesium such that it consumes the water.
As is common for reactions involving solids and solution, the formation of Grignard reagents is often subject to an induction period. During this stage, the passivating oxide on the magnesium is removed. After this induction period, the reactions can be highly exothermic. This exothermicity must be considered when a reaction is scaled-up from laboratory to production plant.
Most organohalides will work, but carbon-fluorine bonds are generally unreactive, except with specially activated magnesium (through Rieke metals). | 0 | Theoretical and Fundamental Chemistry |
Lichenin, also known as lichenan or moss starch, is a complex glucan occurring in certain species of lichens. It can be extracted from Cetraria islandica (Iceland moss). It has been studied since about 1957. | 1 | Applied and Interdisciplinary Chemistry |
The first reported stable metallabenzene was the osmabenzene Os(CHS)CO(PPh). Characteristic of other metallaarenes, the Os-C bonds are about 0.6 Å longer than the C-C bonds (in benzene these are 1.39 Å), resulting in a distortion of the hexagonal ring. H NMR signals for the ring protons are downfield, consistent with aromatic "ring current." Osmabenzene and its derivatives can be regarded as an Os(II), d octahedral complex.
Metallabenzenes have also been characterized with metals ruthenium, iridium, platinum, and rhenium. | 0 | Theoretical and Fundamental Chemistry |
The Cornforth reagent is very toxic to aquatic life and may cause long-term damage to the environment if released in large amounts. It irritates skin and mucous membranes and may induce allergic reactions; it is carcinogenic. The maximum allowable concentration varies between 0.01 and 0.1 mg·m in air depending on the country. Because it contains hexavalent chromium, it is a suspected carcinogen, and as a strong oxidant, pyridinium dichromate promotes fires, releasing carbon monoxide, carbon dioxide and toxic metal smoke. The fire can be extinguished by water or CO. | 0 | Theoretical and Fundamental Chemistry |
Restlessness, apprehension, and anxiety were reported effects after the use of various beta-agonists, particularly after oral or parenteral treatment. In pilot clinical trials with ractopamine, four patients showed little evidence for central nervous system stimulation. Whether long-term treatment with these drugs results in the development of tolerance to these adverse effects is unclear. | 0 | Theoretical and Fundamental Chemistry |
Monoamine nuclei are clusters of cells that primarily use monoamine neurotransmitters to communicate. The raphe nuclei, ventral tegmental area, and locus coeruleus have been included in texts about monoamine nuclei. These nuclei receive a variety of inputs including from other monoamines, as well as from glutaminergic, GABAergic, and substance p related pathways. The catacholaminergic pathways mainly project upwards into the cortical and limbic regions, power sparse descending axons have been observed in animals models. Both ascending and descending serotonergic pathways project from the raphe nuclei. Raphe nuclei in the obscurus, pallid us, and magnus descend into the brainstem and spinal cord, while the raphe ponds, raphe dorsals, and nucleus centralism superior projected up into the medial forebrain bundle before branching off. Monoamine nuclei have been studied in relation to major depressive disorder, with some abnormalities observed, however MAO-B levels appear to be normal during depression in these regions. | 1 | Applied and Interdisciplinary Chemistry |
* Agriculture - Biosolids as an alternative to Chemical Fertilizers
** Biosolids are similar to animal manure in that they consist of various nutrients and organic materials that support the growth of crops, while also enriching the soil and enhancing its capacity to retain water.
** Nutrifor is the brand name of a Biosolid created by Metro Vancouver, Canada, by using biosolids recovered from advanced water treatments. This substance undergoes a process of high-temperature treatment and decomposition by microorganisms to eradicate detrimental bacteria and diminish unpleasant smells. The final outcome is a nutrient-rich, soil-like substance that can be applied directly onto the ground as a fertilizer or incorporated into soil composition.
** The Halton Region, in Ontario, Canada, has introduced a Biosolids Recycling Program where Biosolids are extracted from Halton's 7 wastewater treatment facilities and are recycled as an agricultural fertilizer and soil conditioner. They follow The Ontario Ministry of the Environment, Conservation and Parks (MECP) quality and safety standards for Biosolids processing and re-use. On average, The Halton region has produced over 35,000 tonnes of biosolids per year.
* Forestry
** Biosolids have been identified to accelerate the growth of timber, which facilitates a faster and more effective growth of a forests. The Regional District of Nanaimo, in BC, Canada, has introduced a award-winning Biosolids management program called Forest Fertilization Program, through which the created biosolids have the potential to enhance the growth of trees in areas with limited nutrients, all the while aligning land utilization practices with forestry activities and recreational pursuits.
* Soil Remediation
** Biosolids have proven effective in promoting the growth of sustainable vegetation, mitigating the presence of harmful substances in soil, managing soil erosion, and revitalizing soil profiles for compromised areas which in turn is crucial for the rehabilitation of sites lacking adequate topsoil.
** The Regional District of Nanaimo in partnership with Nanaimo Forest Products Ltd. have introduced a Soil Fabrication Program to manufacture soil at the Harmac Mill in Duke Point, British Columbia, Canada. This is also a planned contingency site for GNPCC biosolids
* Lawns and Home Gardens
** The United States Environmental Protection Agency mentions that biosolids that adhere to the most rigorous standards for reducing pollutants, pathogens, and attractiveness to vectors can be bought by individuals from hardware stores, home and garden centers, or directly from their community's wastewater treatment facility.
* Biogas as an alternative Power Source
** The City of Barrie, in Ontario, Canada has partnered with a Consulting Engineering Firm to convert and optimize Biogas obtained from the Biosolids from their local Wastewater Treatment Facility (WwTF) and to use this Biogas generated from anaerobic digesters as power source for the facility's two cogeneration (cogen) engines and boilers.
** The City of Hamilton, in Ontario, Canada also has a similar Master Plan for the Biosolids present in the city's Wastewater treatments. In their master plan for the next 20 years, they aim to reduce Biosolids Management and foster the use of the produced Biogas for energy production through co-generation.
In a publication by the Government of Canada and the Ontario Federation of Agriculture, the author mentions that using the Land Application method of Biosolids is more cost-effective to taxpayers as compared to the alternative methods of management such as disposal in a landfill. | 1 | Applied and Interdisciplinary Chemistry |
The role of C:N ratio in compost feedstock is similar to that of soil feedstock. The recommendation is around 20-30:1. The microbes prefer a ratio of 30-35:1, but the carbon is usually not completely digested (especially in the case of lignin feedstock), hence the lowered ratio.
An imbalance of C:N ratio causes a slowdown in the composting process and a drop in temperature. When the C:N ratio is less than 15:1, outgassing of ammonium may occur, creating odor and losing nitrogen. A finished compost has a C:N ratio of around 10:1. | 0 | Theoretical and Fundamental Chemistry |
Phosphine is used for pest control, but its usage is strictly regulated due to high toxicity. Gas from phosphine has high mortality rate and has caused deaths in Sweden and other countries.
Because the previously popular fumigant methyl bromide has been phased out in some countries under the Montreal Protocol, phosphine is the only widely used, cost-effective, rapidly acting fumigant that does not leave residues on the stored product. Pests with high levels of resistance toward phosphine have become common in Asia, Australia and Brazil. High level resistance is also likely to occur in other regions, but has not been as closely monitored. Genetic variants that contribute to high level resistance to phosphine have been identified in the dihydrolipoamide dehydrogenase gene. Identification of this gene now allows rapid molecular identification of resistant insects. | 0 | Theoretical and Fundamental Chemistry |
The effects of electrostatic and steric interactions of the substituents as well as orbital interactions such as hyperconjugation are responsible for the relative stability of conformers and their transition states. The contributions of these factors vary depending on the nature of the substituents and may either contribute positively or negatively to the energy barrier. Computational studies of small molecules such as ethane suggest that electrostatic effects make the greatest contribution to the energy barrier; however, the barrier is traditionally attributed primarily to steric interactions.
In the case of cyclic systems, the steric effect and contribution to the free energy can be approximated by A values, which measure the energy difference when a substituent on cyclohexane in the axial as compared to the equatorial position. In large (>14 atom) rings, there are many accessible low-energy conformations which correspond to the strain-free diamond lattice. | 0 | Theoretical and Fundamental Chemistry |
* Roland Clift Developer of Life cycle assessment and broadcaster on environmental issues
* John Coulson (1910–1990) Co-writer of classic UK textbooks
* M. B. Donald (1897 - 1978) Fourth Ramsay professor of Chemical engineering at University College London. Former honorary secretary and vice-president of IChemE, Institution's Donald medal named after him.
* Sir Arthur Duckham (1879–1932) First President of the IChemE
* Ian Fells Noted energy expert and popular science broadcaster
* Trevor Kletz (1922-2013) Noted safety expert
* Ashok Kumar (1956–2010) UK Member of Parliament
* Frank Lees (1931–1999) author of major safety encyclopaedia
* Bodo Linnhoff His 1979 PhD thesis led to Pinch Technology which has enabled companies to save large amounts of energy
* K. B. Quinan (1878–1958) An American who, according to Lloyd George "did more than any other single individual to win the (First World) War"
* Jack Richardson (1929–2011) Co-writer of classic UK textbooks
* P. N. Rowe (1919-2014) Fifth Ramsay professor of chemical engineering at University College London. He was president of the Institution between 1981 and 1982.
* Meredith Thring (1915–2006) prolific inventor, futurologist and early proponent of sustainability | 1 | Applied and Interdisciplinary Chemistry |
(a) Cloning: RM systems can be cloned into plasmids and selected because of the resistance provided by the methylation enzyme. Once the plasmid begins to replicate, the methylation enzyme will be produced and methylate the plasmid DNA, protecting it from a specific restriction enzyme.
(b) Restriction fragment length polymorphisms: Restriction enzymes are also used to analyse the composition of DNA in regard to presence or absence of mutations that affect the REase cleavage specificity. When wild-type and mutants are analysed by digestion with different REases, the gel-electrophoretic products vary in length, largely because mutant genes will not be cleaved in a similar pattern as wild-type for presence of mutations that render the REases non-specific to the mutant sequence. | 1 | Applied and Interdisciplinary Chemistry |
Agnes Luise Wilhelmine Pockels (14 February 1862 – 21 November 1935) was a German chemist whose research was fundamental in establishing the modern discipline known as surface science, which describes the properties of liquid and solid surfaces and interfaces.
Pockels became interested in fundamental research in surface science through observations of soaps and soapy water in her own home while washing dishes. She devised a surface film balance technique to study the behavior of molecules such as soaps and surfactants at air-liquid interfaces. From these studies, Pockels defined the "Pockels Point" which is the minimum area that a single molecule can occupy in monomolecular films.
Pockels was an autodidact. She was not a paid, professional scientist and had no institutional affiliation and so is an example of a citizen scientist.
By contrast, her brother Friedrich Carl Alwin Pockels, for whom the Pockels effect was named, was a professor of theoretical physics at the University of Heidelberg. | 0 | Theoretical and Fundamental Chemistry |
In chemistry, sigma hole interactions (or σ-hole interactions) are a family of intermolecular forces that can occur between several classes of molecules and arise from an energetically stabilizing interaction between a positively-charged site, termed a sigma hole, and a negatively-charged site, typically a lone pair, on different atoms that are not covalently bonded to each other. These interactions are usually rationalized primarily via dispersion, electrostatics, and electron delocalization (similar to Lewis-acid/base coordination) and are characterized by a strong directional preference that allows control over supramolecular chemistry. | 0 | Theoretical and Fundamental Chemistry |
The Pidgeon process is a practical method for smelting magnesium. The most common method involves the raw material, dolomite being fed into an externally heated reduction tank and then thermally reduced to metallic magnesium using 75% ferrosilicon as a reducing agent in a vacuum. Overall the processes in magnesium smelting via the Pidgeon process involve dolomite calcination, grinding and pelleting, and vacuum thermal reduction. Besides the Pidgeon process, electrolysis of magnesium chloride for commercial production of magnesium is also used, at one point in time accounting for 75% of the world's magnesium production. | 1 | Applied and Interdisciplinary Chemistry |
The best method of classifying a water mass is through using a T-S diagram. In the diagram pictured at the top, it categorises a water mass by the temperature and salinity of the water and is represented by a single point. However, water masses are not constant. Throughout time climates can change, seasons can drag out, or there could be less rainfall meaning that the water masses might change in temperature or salinity. To have a complete water mass classification, it requires the water type of the source and the standard deviations of the temperature and salinity. It can take many years to establish the standard deviations of the water mass and requires constant surveillance. Once all of the necessary measures are completed, the data will now determine what the current density of the water is and help further classify the water mass. | 0 | Theoretical and Fundamental Chemistry |
KAP1 can regulate genomic transcription through a variety of mechanisms, many of which remain somewhat unclear. Studies have shown that KAP1 can repress transcription by binding directly to the genome (which can be sufficient in and of itself) or through the induction of heterochromatin formation via the Mi2α-SETB1-HP1 macromolecular complex. KAP1 can also interact with histone methyltransferases and deacetylases via the C-terminal PHD and Bromodomain to control transcription epigenetically. | 1 | Applied and Interdisciplinary Chemistry |
The M30 Apoptosense® ELISA is a non-invasive test for the detection of apoptosis of epithelially derived cells. Caspases are activated in apoptotic cells and cleave intracellular protein substrates. Keratin 18 (K18) is one such substrate, expressed by many epithelial cells (e.g. hepatocytes, intestinal cells, breast cells, prostate cells). Cleaved K18 is released into the circulation after cell death. The main uses of M30 Apoptosense® ELISA are to:
# Measure apoptosis of tumor cells in response to cytotoxic drugs (breast, prostate and other forms of carcinomas).
# Measure hepatocyte apoptosis to aid the diagnosis of non-alcoholic steatohepatitis (NASH) and steatosis in patients with hepatitis C virus infection.
# Serve as a biomarkers of epithelial apoptosis in liver and intestinal graft-versus-host disease. | 1 | Applied and Interdisciplinary Chemistry |
Preclinical safety pharmacology integrates in silico, in vitro, and in vivo approaches. In vitro safety pharmacology studies are focused on early hazard identification and subsequent compound profiling in order to guide preclinical in vivo safety and toxicity studies. Early compound profiling can flag for receptor-, enzyme-, transporter-, and ion channel-related liabilities of NCEs (e.g., inhibition of the human ether-a-go-go related gene protein (hERG)). Classically, in vivo investigations comprise the use of young adult conscious animals. | 1 | Applied and Interdisciplinary Chemistry |
Since the patient group receiving radioligand therapy is narrow, many health care providers are not equipped or eligible to administer radioligand therapy. PET imaging machines, a lead shielded area, and trained professionals must be available. | 1 | Applied and Interdisciplinary Chemistry |
A chiral sp hybridized isomer contains four different substituents. All four substituents are assigned prorites based on its atomic numbers. After the substituents of a stereocenter have been assigned their priorities, the molecule is oriented in space so that the group with the lowest priority is pointed away from the observer. If the substituents are numbered from 1 (highest priority) to 4 (lowest priority), then the sense of rotation of a curve passing through 1, 2 and 3 distinguishes the stereoisomers. In a configurational isomer, the lowest priority group (most times hydrogen) is positioned behind the plane or the hatched bond going away from the reader. The highest priority group will have an arc drawn connecting to the rest of the groups, finishing at the group of third priority. An arc drawn clockwise, has the rectus (R) assignment. An arc drawn counterclockwise, has the sinister (S) assignment. The names are derived from the Latin for right and left, respectively. When naming an organic isomer, the abbreviation for either rectus or sinister assignment is placed in front of the name in parentheses. For example, 3-methyl-1-pentene with a rectus assignment is formatted as (R)-3-methyl-1-pentene.
A practical method of determining whether an enantiomer is R or S is by using the right-hand rule: one wraps the molecule with the fingers in the direction . If the thumb points in the direction of the fourth substituent, the enantiomer is R; otherwise, it is S.
It is possible in rare cases that two substituents on an atom differ only in their absolute configuration (R or S). If the relative priorities of these substituents need to be established, R takes priority over S. When this happens, the descriptor of the stereocenter is a lowercase letter (r or s) instead of the uppercase letter normally used. | 0 | Theoretical and Fundamental Chemistry |
The most critical eyespot proteins are the photoreceptor proteins that sense light. The photoreceptors found in unicellular organisms fall into two main groups: flavoproteins and retinylidene proteins (rhodopsins). Flavoproteins are characterized by containing flavin molecules as chromophores, whereas retinylidene proteins contain retinal. The photoreceptor protein in Euglena is likely a flavoprotein. In contrast, Chlamydomonas phototaxis is mediated by archaeal-type rhodopsins.
Besides photoreceptor proteins, eyespots contain a large number of structural, metabolic and signaling proteins. The eyespot proteome of Chlamydomonas cells consists of roughly 200 different proteins. | 1 | Applied and Interdisciplinary Chemistry |
The first paper on site-specific enrichment used the ninhydrin reaction to cleave the carboxyl site off alpha-amino acids in photosynthetic organisms. The authors demonstrated an enriched carboxyl site relative to the bulk δC of the molecules, which they attribute to uptake of heavier CO through the Calvin cycle. A recent study applied similar theory to understand enrichments in methionine, which they suggested would be powerful in origin and synthesis studies. | 0 | Theoretical and Fundamental Chemistry |
By selective radio frequency irradiation, NMR spectra can be fully or partially decoupled, eliminating or selectively reducing the coupling effect. Carbon-13 NMR spectra are often recorded with proton decoupling. | 0 | Theoretical and Fundamental Chemistry |
In some Asian cuisines, fish is traditionally fermented with rice to produce lactic acid that preserves the fish. Examples of these dishes include burong isda of the Philippines; narezushi of Japan; and pla ra of Thailand. The same process is also used for shrimp in the Philippines in the dish known as balao-balao. | 1 | Applied and Interdisciplinary Chemistry |
Mary Jane Alvero-Al Mahdi was born in Makati, Philippines on April 29, 1970. She was born to Renato Alvero and Martha Alvero, along with four other children. Her father supported the family as a successful businessman, until he began to develop emphysema. Her father could no longer maintain the business and stayed confined to a bed, leaving her mother to take care of the children and at the same time worked hard to keep the family financially stable. Alvero-Al Mahdi took part and helped her mother by working part time jobs, and at the same time, studied chemical engineering at Adamson University. She graduated, and received her B.S. in chemical engineering in 1991. After graduating, she took the Chemical Engineer Licensure Exam and passed. She worked under a company in Manila before she accepted the job offer in Dubai. | 1 | Applied and Interdisciplinary Chemistry |
The primary industrial use of boric acid is in the manufacture of monofilament fiberglass usually referred to as textile fiberglass. Textile fiberglass is used to reinforce plastics in applications that range from boats, to industrial piping to computer circuit boards.
Boric Acid is used as a Nuclear Poison in modern PWR type Nuclear Reactors as it Reduce Fission Process by Reducing Neutrons Flux. It is used in PWR Nuclear Reactor's Coolant water for Controlling Reactor Power as well as to Perform Emergency Reactor Shutdown.
In the jewelry industry, boric acid is often used in combination with denatured alcohol to reduce surface oxidation and thus formation of firescale on metals during annealing and soldering operations.
Boric acid is used in the production of the glass in LCD flat panel displays.
In electroplating, boric acid is used as part of some proprietary formulas. One such known formula calls for about a 1 to 10 ratio of to nickel(II) sulfate|, a very small portion of sodium lauryl sulfate and a small portion of sulfuric acid|.
The solution of orthoboric acid and borax in 4:5 ratio is used as a fire retarding agent of wood by impregnation.
It is also used in the manufacturing of ramming mass, a fine silica-containing powder used for producing induction furnace linings and ceramics.
Boric acid is added to borax for use as welding flux by blacksmiths.
Boric acid, in combination with polyvinyl alcohol (PVA) or silicone oil, is used to manufacture Silly Putty.
Boric acid is also present in the list of chemical additives used for hydraulic fracturing (fracking) in the Marcellus Shale in Pennsylvania. It is often used in conjunction with guar gum as cross-linking and gelling agent for controlling the viscosity and the rheology of the fracking fluid injected at high pressure in the well. It is important to control the fluid viscosity for keeping in suspension on long transport distances the grains of the propping agents aimed at maintaining the cracks in the shales sufficiently open to facilitate the gas extraction after the hydraulic pressure is relieved. The rheological properties of borate cross-linked guar gum hydrogel mainly depend on the pH value.
Boric acid is used in some expulsion-type electrical fuses as a de-ionization/extinguishing agent. During an electrical fault in an expulsion-type fuse, a plasma arc is generated by the disintegration and rapid spring-loaded separation of the fusible element, which is typically a specialized metal rod that passes through a compressed mass of boric acid within the fuse assembly. The high-temperature plasma causes the boric acid to rapidly decompose into water vapor and boric anhydride, and in-turn, the vaporization products de-ionize the plasma, helping to interrupt the electrical fault. | 0 | Theoretical and Fundamental Chemistry |
The original betaine, N,N,N-trimethylglycine, was named after its discovery in sugar beet (Beta vulgaris subsp. vulgaris) in the nineteenth century. It is a small N-trimethylated amino acid. It is a zwitterion, which cannot isomerize because there is no labile hydrogen atom attached to the nitrogen atom. This substance may be called glycine betaine to distinguish it from other betaines. | 0 | Theoretical and Fundamental Chemistry |
Subsets and Splits