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Brownian motion follows the Langevin equation, which can be solved for many different stochastic forcings with results being averaged (canonical ensemble in molecular dynamics). However, instead of this computationally intensive approach, one can use the Fokker–Planck equation and consider the probability of the particle having a velocity in the interval when it starts its motion with at time 0. | 1 | Applied and Interdisciplinary Chemistry |
Data may also be created in the manufacturing of the media, as is the case with most optical disc formats for commercial data distribution. In this case, the user can not write to the disc it is a ROM format. Data may be written by a nonlinear optical method, but in this case the use of very high power lasers is acceptable so media sensitivity becomes less of an issue.
The fabrication of discs containing data molded or printed into their 3D structure has also been demonstrated. For example, a disc containing data in 3D may be constructed by sandwiching together a large number of wafer-thin discs, each of which is molded or printed with a single layer of information. The resulting ROM disc can then be read using a 3D reading method. | 0 | Theoretical and Fundamental Chemistry |
In the gene identification process, MG-RAST employs a machine learning approach known as FragGeneScan. This method is utilized to identify gene sequences within the metagenomic or metatranscriptomic data.
For the identification of ribosomal RNA sequences, MG-RAST initiates a BLAT search against a reduced version of the SILVA database. This step allows the system to pinpoint and categorize ribosomal RNA sequences within the dataset, contributing to a more detailed understanding of the biological composition of the analyzed metagenomes or metatranscriptomes. | 1 | Applied and Interdisciplinary Chemistry |
A racemic mixture is denoted by the prefix (±)- or dl- (for sugars the prefix - may be used), indicating an equal (1:1) mixture of dextro and levo isomers. Also the prefix rac- (or racem-) or the symbols RS and SR (all in italic letters) are used.
If the ratio is not 1:1 (or is not known), the prefix (+)/(−), - or d/l- (with a slash) is used instead.
The usage of d and l is discouraged by IUPAC. | 0 | Theoretical and Fundamental Chemistry |
Tissue clearing methods have varying compatibility with different methods of fluorescent labeling. Some are better suited to pre-clearing tagging approaches, such as genetic labeling. while others require post-clearing tagging, such as immunolabeling and chemical dye labeling. | 1 | Applied and Interdisciplinary Chemistry |
In October 2011, the first clinical trial was announced for the treatment of choroideremia. Dr. Robert MacLaren of the University of Oxford, who lead the trial, co-developed the treatment with Dr. Miguel Seabra of the Imperial College, London. This Phase 1/2 trial used subretinal AAV to restore the REP gene in affected patients.
Initial results of the trial were reported in January 2014 as promising as all six patients had better vision. | 1 | Applied and Interdisciplinary Chemistry |
In a potential application in nanotechnology, the diazonium salts 4-chlorobenzenediazonium tetrafluoroborate very efficiently functionalizes single wall nanotubes. In order to exfoliate the nanotubes, they are mixed with an ionic liquid in a mortar and pestle. The diazonium salt is added together with potassium carbonate, and after grinding the mixture at room temperature the surface of the nanotubes are covered with chlorophenyl groups with an efficiency of 1 in 44 carbon atoms. These added subsituents prevent the tubes from forming intimate bundles due to large cohesive forces between them, which is a recurring problem in nanotube technology.
It is also possible to functionalize silicon wafers with diazonium salts forming an aryl monolayer. In one study, the silicon surface is washed with ammonium hydrogen fluoride leaving it covered with silicon–hydrogen bonds (hydride passivation). The reaction of the surface with a solution of diazonium salt in acetonitrile for 2 hours in the dark is a spontaneous process through a free radical mechanism:
So far grafting of diazonium salts on metals has been accomplished on iron, cobalt, nickel, platinum, palladium, zinc, copper and gold surfaces. Also grafting to diamond surfaces has been reported. One interesting question raised is the actual positioning on the aryl group on the surface. An in silico study demonstrates that in the period 4 elements from titanium to copper the binding energy decreases from left to right because the number of d-electrons increases. The metals to the left of iron are positioned tilted towards or flat on the surface favoring metal to carbon pi bond formation and those on the right of iron are positioned in an upright position, favoring metal to carbon sigma bond formation. This also explains why diazonium salt grafting thus far has been possible with those metals to right of iron in the periodic table. | 0 | Theoretical and Fundamental Chemistry |
Fig. 5 shows a so-called DC SQUID. It consists of two superconductors connected by two weak links. The fluxoid quantization of a loop through the two bulk superconductors and the two weak links demands
If the self-inductance of the loop can be neglected the magnetic flux in the loop Φ is equal to the applied flux
with B the magnetic field, applied perpendicular to the surface, and A the surface area of the loop. The total supercurrent is given by
Substitution of Eq() in () gives
Using a well known geometrical formula we get
Since the sin-function can vary only between −1 and +1 a steady solution is only possible if the applied current is below a critical current given by
Note that the critical current is periodic in the applied flux with period . The dependence of the critical current on the applied flux is depicted in Fig. 6. It has a strong resemblance with the interference pattern generated by a laser beam behind a double slit. In practice the critical current is not zero at half integer values of the flux quantum of the applied flux. This is due to the fact that the self-inductance of the loop cannot be neglected. | 0 | Theoretical and Fundamental Chemistry |
Water treatment systems often require the degradation of hazardous compounds. These treatment processes are dubbed Advanced oxidation processes, and are key in destroying byproducts from disinfection, pesticides, and other hazardous compound. There is an emerging effort to enable these processes to destroy more tenacious compounds, especially PFAS | 0 | Theoretical and Fundamental Chemistry |
When tested by commercial laboratories, alguronic acid showed significant results in several skin benefit and anti-aging parameters, both independently and compared to other well-known anti-aging ingredients. The funding for these third party laboratories is not disclosed. The acid, an heterogeneous mix of polysaccharides, will vary in composition depending on the growth conditions of the mixed algae cultures; the individual structures of the components of this mix has not been established.
Alguronic acid is not naturally present in human skin, should not be affected by skin enzymes, and is unlikely to be used by the skin. Conversely, hyaluronic acid is distributed throughout the body, is naturally produced in the skin, and, based on its ability to retain moisture, plays a major role in tissue structure and repair. In testing done by commercial laboratories, alguronic acid was found to inhibit production of hyaluronic-acid-degrading enzymes by up to 67%. The relevance of this inhibition in vitro to skin physiology is unknown. | 0 | Theoretical and Fundamental Chemistry |
#DNA-PET: Because PET represent connectivity between the tags, the use of PET in genome re-sequencing has advantages over the use of single reads. This application is called pairwise end sequencing, known colloquially as double-barrel shotgun sequencing. Anchoring one half of the pair uniquely to a single location in the genome allows mapping of the other half that is ambiguous. Ambiguous reads are those that map to more than a single location. This increased efficiency reduces the cost of sequencing as these ambiguous sequences, or reads, would normally be discarded. The connectivity of PET sequences also allows detection of structural variations: insertions, deletions, duplications, inversions, translocations. During the construction of the PET library, the fragments can be selected to all be of a certain size. After mapping, the PET sequences are thus expected to be consistently a particular distance away from each other. A discrepancy from this distance indicates a structural variation between the PET sequences. For example (Figure on the right): a deletion in the sequenced genome will have reads that map further away than expected in the reference genome as the reference genome will have a segment of DNA that is not present in the sequenced genome.
#ChIP-PET: The combined use of chromatin immunoprecipitation (ChIP) and PET is used to detect regions of DNA bound by a protein of interest. ChIP-PET has the advantage over single read sequencing by reducing ambiguity of the reads generated. The advantage over chip hybridization (ChIP-Chip) is that hybridization tiling arrays do not have the statistical sensitivity that sequence reads have. However, ChIP-PET, ChIP-Seq and ChIP-chip have all been highly successful.
#ChIA-PET: The application of PET sequencing on chromatin interaction analysis. It is a genome-wide strategy for finding de novo long-range interactions between DNA elements bound by protein factors. The first ChIA-PET was developed by Fullwood et al.. (2009) to generate a map of the interactions between chromatin bound by oestrogen receptor α (ER-α) in oestrogen-treated human breast adenocarcinoma cells. ChIA-PET is an unbiased way to analyze interactions and higher-order chromatin structures because it can detect interactions between unknown DNA elements. In contrast, 3C and 4C methods are used to detect interactions involving a specific target region in the genome. ChIA-PET is similar to finding fusion genes through RNA-PET in that the paired tags map to different regions in the genome. However, ChIA-PET involves artificial ligations between different DNA fragments located at different genomic regions, rather than naturally occurring fusion between two genomic regions as in RNA-PET.
#RNA-PET: This application is used for studying the transcriptome: transcripts, gene structures, and gene expressions. The PET library is generated using full length cDNAs, so the ditags represent the 5’ capped and the 3’ polyA tail signatures of individual transcripts. Therefore, RNA-PET is especially useful for demarcating the boundaries of transcription units. This will help identify alternative transcription start sites and polyadenylation sites of genes. RNA-PET could also be used to detect fusion genes and trans-splicing, but further experiment is needed to distinguish between them. Other methods of finding the boundaries of transcripts include the single-tag strategies CAGE, SAGE, and the most recent SuperSAGE, with the CAGE and 5’ SAGE defining the transcription start sites and the 3’ SAGE defining the polyadenylation sites. The advantages of PET sequencing over these methods are that PET identify both ends of the transcripts and, at the same time, provide more specificity when mapping back to the genome. Sequencing the cDNAs can reveal the structures of transcripts in great details, but this approach is much more expensive than RNA-PET sequencing, especially for characterizing the whole transcriptome. The major limitation of RNA-PET is the lack of information regarding the organization of the internal exons of transcripts. Therefore, RNA-PET is not suitable for detecting alternative splicing. In addition, if the cloning procedure is used construct the cDNA library before generating the PETs, cDNAs that are difficult to clone (as a result of long transcripts) would have lower coverage. Similarly, transcripts (or transcript isoforms) with low expression levels would likely be under-represented as well. | 1 | Applied and Interdisciplinary Chemistry |
Thermogravimetric kinetics may be explored for insight into the reaction mechanisms of thermal (catalytic or non-catalytic) decomposition involved in the pyrolysis and combustion processes of different materials.
Activation energies of the decomposition process can be calculated using Kissinger method.
Though a constant heating rate is more common, a constant mass loss rate can illuminate specific reaction kinetics. For example, the kinetic parameters of the carbonization of polyvinyl butyral were found using a constant mass loss rate of 0.2 wt %/min. | 0 | Theoretical and Fundamental Chemistry |
While the exact mechanism of action is still unknown many important protein physical properties play a part in the Vroman Effect. Proteins have many properties that are important to take into consideration when discussing protein adsorption. These properties include the protein size, charge, mobility, stability, and the structure and composition of the different protein domains that make up the protein's tertiary structure. Protein size determines the molecular weight. Protein charge determines whether preferentially or selective favorable interactions will exist between the protein and a biomaterial. Protein mobility plays a factor in adsorption kinetics. | 0 | Theoretical and Fundamental Chemistry |
Creosote is a category of carbonaceous chemicals formed by the distillation of various tars and pyrolysis of plant-derived material, such as wood, or fossil fuel. They are typically used as preservatives or antiseptics.
Some creosote types were used historically as a treatment for components of seagoing and outdoor wood structures to prevent rot (e.g., bridgework and railroad ties, see image). Samples may be found commonly inside chimney flues, where the coal or wood burns under variable conditions, producing soot and tarry smoke. Creosotes are the principal chemicals responsible for the stability, scent, and flavor characteristic of smoked meat; the name is derived .
The two main kinds recognized in industry are coal-tar creosote and wood-tar creosote. The coal-tar variety, having stronger and more toxic properties, has chiefly been used as a preservative for wood; coal-tar creosote was also formerly used as an escharotic, to burn malignant skin tissue, and in dentistry, to prevent necrosis, before its carcinogenic properties became known. The wood-tar variety has been used for meat preservation, ship treatment, and such medical purposes as an anaesthetic, antiseptic, astringent, expectorant, and laxative, though these have mostly been replaced by modern formulations.
Varieties of creosote have also been made from both oil shale and petroleum, and are known as oil-tar creosote when derived from oil tar, and as water-gas-tar creosote when derived from the tar of water gas. Creosote also has been made from pre-coal formations such as lignite, yielding lignite-tar creosote, and peat, yielding peat-tar creosote. | 0 | Theoretical and Fundamental Chemistry |
The most widely used anodizing specification in the US is a U.S. military spec, MIL-A-8625, which defines three types of aluminium anodizing. Type I is chromic acid anodizing, Type II is sulphuric acid anodizing, and Type III is sulphuric acid hard anodizing. Other anodizing specifications include more MIL-SPECs (e.g., MIL-A-63576), aerospace industry specs by organizations such as SAE, ASTM, and ISO (e.g., AMS 2469, AMS 2470, AMS 2471, AMS 2472, AMS 2482, ASTM B580, ASTM D3933, ISO 10074, and BS 5599), and corporation-specific specs (such as those of Boeing, Lockheed Martin, Airbus and other large contractors). AMS 2468 is obsolete. None of these specifications define a detailed process or chemistry, but rather a set of tests and quality assurance measures which the anodized product must meet. BS 1615 guides the selection of alloys for anodizing. For British defense work, a detailed chromic and sulfuric anodizing processes are described by DEF STAN 03-24/3 and DEF STAN 03-25/3 respectively. | 1 | Applied and Interdisciplinary Chemistry |
Due to natural occurrence of radioactive elements such as thorium and radium in rare-earth ore, mining operations also result in production of waste and mineral deposits that are slightly radioactive. | 0 | Theoretical and Fundamental Chemistry |
The vapour-phase-mediated antimicrobial activity (VMAA) is the inhibitory or cidal antimicrobial activity of a molecule in a liquid culture, following its initial evaporation and migration via the vapour-phase Two new in vitro assays i.e. the vapour-phase-mediated patch assay and the vapour-phase-mediated susceptibility assay were developed to detect and quantify the VMAA. Both assays belong to the newest class of vaporisation assays i.e. the broth microdilution derived vaporisation assays. In contrast, most other vaporisation assays belong to the class of agar disk diffusion derived vaporisation assays and quantify the antimicrobial activity of the vapour-phase itself. Both classes of vaporisation assays are useful and measure different aspects of the antimicrobial capacity of molecules. | 1 | Applied and Interdisciplinary Chemistry |
The particle size, or fineness, of powder materials is very often critical to their performance.
Measurement of air permeability can be performed very rapidly, and does not require the powder to be exposed to vacuum or to gases or vapours, as is necessary for the BET method for determination of specific surface area. This makes it both very cost-effective, and also allows it to be used for materials which may be unstable under vacuum.
When a powder reacts chemically with a liquid or gas at the surface of its particles, the specific surface is directly related to its rate of reaction. The measurement is therefore important in the manufacture of many processed materials.
In particular, air permeability is almost universally used in the cement industry as a gauge of product fineness which is directly related to such properties as speed of setting and rate of strength development.
Other fields where air permeability has been used to determine specific surface area include:
* Paint and pigments
* Pharmaceuticals
* Metallurgical powders, including sintered metal filters.
In some fields, particularly powder metallurgy, the related Fisher number is the parameter of interest. This is the equivalent average particle diameter, assuming that the particles are spherical and have uniform size. Historically, the Fisher number was obtained by measurement using the Fisher Sub-sieve Sizer, a commercial instrument containing an air pump and pressure regulator to establish a constant air flow, which is measured using a flowmeter. A number of manufacturers make equivalent instruments, and the Fisher number can be calculated from air permeability specific surface area values. | 1 | Applied and Interdisciplinary Chemistry |
It has been shown that as reservoir simulators use the primary drainage capillary pressure data for saturation-height modeling calculations, primary drainage capillary pressure data should be averaged in the same manner that water saturations are averaged. Also, as reservoir simulators use the imbibition and secondary drainage capillary pressure data for fluids displacement calculations, these capillary pressures should not be averaged like primary drainage capillary pressure data. These can be averaged by Leverett J-function. The averaging equations are as follows | 1 | Applied and Interdisciplinary Chemistry |
When the generator is left unused, Mo decays to Tc, which in turn decays to Tc. The half-life of Tc is far longer than its metastable isomer, so the ratio of Tc to Tc increases over time. Both isomers are carried out by the elution process and react equally well with the ligand, but the Tc is an impurity useless to imaging (and cannot be separated).
The generator is washed of Tc and Tc at the end of the manufacturing process of the generator, but the ratio of Tc to Tc then builds up again during transport or any other period when the generator is left unused. The first few elutions will have reduced effectiveness because of this high ratio. | 0 | Theoretical and Fundamental Chemistry |
The use of biofilters is common in closed aquaculture systems, such as recirculating aquaculture systems (RAS). The biofiltration techniques used in aquaculture can be separated into three categories: biological, physical, and chemical. The main biological method is nitrification, physical methods include mechanical techniques and sedimentation, and chemical methods are usually used in tandem with one of the other methods. Some farms use seaweed, such as those from the genera Ulva, to take excess nutrients out of the water and release oxygen into the ecosystem in a “recirculation system” while also serving as a source of income when they sell the seaweed for safe human consumption.
Many designs are used, with different benefits and drawbacks, however the function is the same: reducing water exchanges by converting ammonia to nitrate. Ammonia (NH and NH) originates from the brachial excretion from the gills of aquatic animals and from the decomposition of organic matter. As ammonia-N is highly toxic, this is converted to a less toxic form of nitrite (by Nitrosomonas sp.) and then to an even less toxic form of nitrate (by Nitrobacter sp.). This "nitrification" process requires oxygen (aerobic conditions), without which the biofilter can crash. Furthermore, as this nitrification cycle produces H, the pH can decrease which necessitates the use of buffers such as lime. | 1 | Applied and Interdisciplinary Chemistry |
Juvenile retinoschisis is a disease that affects the nerve tissue in the eye. This disease is an X-linked recessive degenerative disease of the central macula region, and it is caused by mutation in the RSI gene encoding the protein retinoschisin. Retinoschisin is produced in the photoreceptor and bipolar cells and it is critical in maintaining the synaptic integrity of the retina.
Specifically the AAV 5 vector containing the wild-type human RSI cDNA driven by a mouse opsin promoter showed long-term retinal functional and structural recovery. Also the retinal structural reliability improved greatly after the treatment, characterized by an increase in the outer nuclear layer thickness. | 1 | Applied and Interdisciplinary Chemistry |
Christopher J. Chetsanga (born 1935 in Murehwa, Rhodesia) is a prominent Zimbabwean scientist who is a member of the African Academy of Sciences and The World Academy of Sciences. He discovered two enzymes involved in DNA repair. He has also held various academic administrative posts like Vice-Chancellor, Director and Dean. | 1 | Applied and Interdisciplinary Chemistry |
Complexes of polymers with DNA are called polyplexes. Most polyplexes consist of cationic polymers and their fabrication is based on self-assembly by ionic interactions. One important difference between the methods of action of polyplexes and lipoplexes is that polyplexes cannot directly release their DNA load into the cytoplasm. As a result, co-transfection with endosome-lytic agents such as inactivated adenovirus was required to facilitate nanoparticle escape from the endocytic vesicle made during particle uptake. However, a better understanding of the mechanisms by which DNA can escape from endolysosomal pathway, i.e. proton sponge effect, has triggered new polymer synthesis strategies such as incorporation of protonable residues in polymer backbone and has revitalized research on polycation-based systems.
Due to their low toxicity, high loading capacity, and ease of fabrication, polycationic nanocarriers demonstrate great promise compared to their rivals such as viral vectors which show high immunogenicity and potential carcinogenicity, and lipid-based vectors which cause dose dependence toxicity. Polyethyleneimine and chitosan are among the polymeric carriers that have been extensively studied for development of gene delivery therapeutics. Other polycationic carriers such as poly(beta-amino esters) and polyphosphoramidate are being added to the library of potential gene carriers. In addition to the variety of polymers and copolymers, the ease of controlling the size, shape, surface chemistry of these polymeric nano-carriers gives them an edge in targeting capability and taking advantage of enhanced permeability and retention effect. | 1 | Applied and Interdisciplinary Chemistry |
Historians debate whether bloomery-based ironworking ever spread to China from the Middle East. One theory suggests that metallurgy was introduced through Central Asia. In 2008, two iron fragments were excavated at the Mogou site, in Gansu. They have been dated to the 14th century BC, belonging to the period of Siwa culture, suggesting an independent Chinese origin. One of the fragments was made of bloomery iron rather than meteoritic iron.
The earliest iron artifacts made from bloomeries in China date to end of the 9th century BC. Cast iron was used in ancient China for warfare, agriculture and architecture. Around 500 BC, metalworkers in the southern state of Wu achieved a temperature of 1130 °C. At this temperature, iron combines with 4.3% carbon and melts. The liquid iron can be cast into molds, a method far less laborious than individually forging each piece of iron from a bloom.
Cast iron is rather brittle and unsuitable for striking implements. It can be decarburized to steel or wrought iron by heating it in air for several days. In China, these iron working methods spread northward, and by 300 BC, iron was the material of choice throughout China for most tools and weapons. A mass grave in Hebei province, dated to the early 3rd century BC, contains several soldiers buried with their weapons and other equipment. The artifacts recovered from this grave are variously made of wrought iron, cast iron, malleabilized cast iron, and quench-hardened steel, with only a few, probably ornamental, bronze weapons.
During the Han Dynasty (202 BC–220 AD), the government established ironworking as a state monopoly, repealed during the latter half of the dynasty and returned to private entrepreneurship, and built a series of large blast furnaces in Henan province, each capable of producing several tons of iron per day. By this time, Chinese metallurgists had discovered how to fine molten pig iron, stirring it in the open air until it lost its carbon and could be hammered (wrought). In modern Mandarin-Chinese, this process is now called chao, literally stir frying. Pig iron is known as raw iron, while wrought iron is known as cooked iron. By the 1st century BC, Chinese metallurgists had found that wrought iron and cast iron could be melted together to yield an alloy of intermediate carbon content, that is, steel.
According to legend, the sword of Liu Bang, the first Han emperor, was made in this fashion. Some texts of the era mention "harmonizing the hard and the soft" in the context of ironworking; the phrase may refer to this process. The ancient city of Wan (Nanyang) from the Han period forward was a major center of the iron and steel industry. Along with their original methods of forging steel, the Chinese had also adopted the production methods of creating Wootz steel, an idea imported from India to China by the 5th century AD.
During the Han Dynasty, the Chinese were also the first to apply hydraulic power (i.e. a waterwheel) in working the bellows of the blast furnace. This was recorded in the year 31 AD, as an innovation by the Chinese mechanical engineer and politician Du Shi, Prefect of Nanyang. Although Du Shi was the first to apply water power to bellows in metallurgy, the first drawn and printed illustration of its operation with water power appeared in 1313 AD, in the Yuan Dynasty era text called the Nong Shu.
In the 11th century, there is evidence of the production of steel in Song China using two techniques: a "berganesque" method that produced inferior, heterogeneous steel and a precursor to the modern Bessemer process that utilized partial decarbonization via repeated forging under a cold blast. By the 11th century, there was a large amount of deforestation in China due to the iron industry's demands for charcoal. By this time however, the Chinese had learned to use bituminous coke to replace charcoal, and with this switch in resources many acres of prime timberland in China were spared. | 1 | Applied and Interdisciplinary Chemistry |
The earliest land plants evolved from aquatic plants around (Ma) in the Ordovician period. Many plants have adapted to an iodine-deficient terrestrial environment by removing iodine from their metabolism; in fact, iodine is essential only for animal cells. An important antiparasitic action is caused by the blockage in the transport of iodide of animal cells, inhibiting sodium-iodide symporter (NIS). Many plant pesticides are glycosides (such as cardiac digitoxin) and cyanogenic glycosides that liberate cyanide, which, by blocking cytochrome c oxidase and NIS, is poisonous only for a large part of parasites and herbivores and not for the plant cells, in which it seems useful in the seed dormancy phase. Iodide is not a pesticide but is oxidized, by vegetable peroxidase to iodine, which is a strong oxidant able to kill bacteria, fungi, and protozoa.
The Cretaceous period saw the appearance of more plant defense mechanisms. The diversification of flowering plants (angiosperms) at that time is associated with the sudden burst of speciation in insects. This diversification of insects represented a major selective force in plant evolution and led to the selection of plants that had defensive adaptations. Early insect herbivores were mandibulate and bit or chewed vegetation, but the evolution of vascular plants lead to the co-evolution of other forms of herbivory, such as sap-sucking, leaf mining, gall forming and nectar-feeding.
The relative abundance of different species of plants in ecological communities including forests and grasslands may be determined in part by the level of defensive compounds in the different species. Since the cost of replacing damaged leaves is higher in conditions where resources are scarce, it may also be that plants growing in areas where water and nutrients are scarce may invest more resources into anti-herbivore defenses, resulting in slower plant growth. | 1 | Applied and Interdisciplinary Chemistry |
The phosphatome of an organism is the set of phosphatase genes in its genome. Phosphatases are enzymes that catalyze the removal of phosphate from biomolecules. Over half of all cellular proteins are modified by phosphorylation which typically controls their functions. Protein phosphorylation is controlled by the opposing actions of protein phosphatases and protein kinases.
Most phosphorylation sites are not linked to a specific phosphatase, so the phosphatome approach allows a global analysis of dephosphorylation, screening to find the phosphatase responsible for a given reaction, and comparative studies between different phosphatases, similar to how protein kinase research has been impacted by the kinome approach. | 1 | Applied and Interdisciplinary Chemistry |
The physicochemical profiling of poorly soluble drug candidates performed using a HTS surface tension device. Allowed prediction of penetration through the blood–brain barrier. | 0 | Theoretical and Fundamental Chemistry |
Dexketoprofen is a nonsteroidal anti-inflammatory drug (NSAID). It is manufactured by Menarini, under the tradename Keral. It is available in the UK, as dexketoprofen trometamol, as a prescription-only drug and in Latin America as Enantyum, produced by Menarini. Also, in Italy and Spain it is available as an over-the-counter drug (OTC) under the trade name Enandol or Enantyum. In Hungary it is available from a pharmacy as "Ketodex". In Turkey, it is an over the counter medicine under the name "Arveles". In Latvia, Lithuania and Estonia it is available as an OTC under the tradename Dolmen
In Mexico it is available in tablet form as "Stadium" made by Menarini. It is the dextrorotatory stereoisomer of ketoprofen. | 0 | Theoretical and Fundamental Chemistry |
The main advantage over other filtration systems is the reduction in energy consumption, up to 90% because no air flows through the discs due to the use of capillary force acting on the pores. Air breakthrough is prevented by the fine pores of the filter, thus allowing retention of higher vacuum levels. Therefore, the vacuum losses are less, which means the vacuum pump required is smaller than in conventional disc filters, thus minimizing operating costs. Power consumed by a vacuum ceramic filter with 45 m of filtration area is 15 kW while 170 kW is consumed by similar filters with cloth membranes.
Generally, conventional disc filters are not suitable for cake washing because the water quickly runs off the surface of the cake. As the cake solids are sprayed with a wash liquid to remove impurities, they are not suitable for conventional filtration systems where channelling or uneven distribution occurs, leading to cake cracking. However, cake washing has been proved to be more efficient with vacuum ceramic filters due to the steady flow profile and the even distribution of the cake.
A further advantage of vacuum ceramic filter is the high output capacity with a very low water content and drier filter cake. By comparison, the performance of a VDFK-3 ceramic filter was compared with the existing BOU-40 and BLN40-3 drum type vacuum filters to filter aluminium hydroxide. From the results, the average moisture content was 5% (abs? or rel?) lower when a vacuum ceramic filter was used.
Vacuum ceramic filters also have a longer service life while cloth filters have to be replaced, which eventually increases the moisture content of the cake, lowers the productivity and disturbs the production operations. In addition, the ceramic filter is both mechanically and chemically reliable enough to withstand regeneration.
Whilst the vacuum ceramic filter has proved to be a great innovation, there are still some limitations involved when operating the equipment. Ceramic filters exhibit large fluctuations in the recoiling washing pressure (0.05~0.35 MPa). This raises the short-term negative pressure and induces dilute acid due to the falling suck phenomenon. Therefore, the cleaning effect of the ceramic plates and the efficiency of the filter will be negatively affected. | 0 | Theoretical and Fundamental Chemistry |
Till the 1950s, only one manuscript of Vaiseshika sutra was known and this manuscript was part of a bhasya by the 15th century Sankaramisra. Scholars had doubted its authenticity, given the inconsistencies in this manuscript and the quotes in other Hindu, Jaina and Buddhist literature claiming to be from the Vaisheshika Sutra. In the 1950s and early 1960s, new manuscripts of Vaiśeṣika Sūtra were discovered in distant parts of India, which were later identified as this Sutra. These newer manuscripts are quite different, more consistent with the historical literature, and suggests that, like other major texts and scriptures of Hinduism, Vaiśeṣika Sūtra too suffered interpolations, errors in transmission and distortion over time. A critical edition of the Vaiśeṣika Sūtra is now available. | 1 | Applied and Interdisciplinary Chemistry |
The Baeyer–Drewsen indigo synthesis (1882) is an organic reaction in which indigo is prepared from 2-nitrobenzaldehyde and acetone The reaction was developed by von Baeyer in 1880 to produce the first synthetic indigo at laboratory scale. This procedure is not used at industrial scale.
The reaction is classified as an aldol condensation. As a practical route to indigo, this method was displaced by routes from aniline. | 0 | Theoretical and Fundamental Chemistry |
The Irving–Williams series refers to high-spin, octahedral, divalent metal ion of the first transition series. It places the stabilities of complexes in the order
:Mn < Fe < Co < Ni < Cu > Zn
This order was found to hold for a wide variety of ligands. There are three strands to the explanation of the series.
#The ionic radius is expected to decrease regularly for Mn to Zn. This would be the normal periodic trend and would account for the general increase in stability.
#The crystal field stabilisation energy (CFSE) increases from zero for manganese(II) to a maximum at nickel(II). This makes the complexes increasingly stable. CFSE returns to zero for zinc(II).
#Although the CFSE for copper(II) is less than for nickel(II), octahedral copper(II) complexes are subject to the Jahn–Teller effect which results in a complex having extra stability.
Another example of the effect of ionic radius the steady increase in stability of complexes with a given ligand along the series of trivalent lanthanide ions, an effect of the well-known lanthanide contraction. | 0 | Theoretical and Fundamental Chemistry |
The use of supercritical carbon dioxide, instead of water, has been examined as a geothermal working fluid. | 0 | Theoretical and Fundamental Chemistry |
Due to the ability of Ang to protect motoneurons (MNs), causal links between Ang mutations and amyotrophic lateral sclerosis (ALS) are likely. The angiogenic factors associated with Ang may protect the central nervous system and MNs directly. Experiments with wild type Ang found that it slows MN degeneration in mice that had developed ALS, providing evidence for further development of Ang protein therapy in ALS treatment. Angiogenin expression in Parkinsons disease is dramatically decreased in the presence of alpha-synuclein (α-syn) aggregations. Exogenous angiogenin applied to dopamine-producing cells leads to the phosphorylation of PKB/AKT and the activation of this complex inhibits cleavage of caspase 3 and apoptosis when cells are exposed to a Parkinsons-like inducing substance. | 1 | Applied and Interdisciplinary Chemistry |
In 1919, Ernest Rutherford was able to accomplish transmutation of nitrogen into oxygen at the University of Manchester, using alpha particles directed at nitrogen N + α → O + p. This was the first observation of an induced nuclear reaction, that is, a reaction in which particles from one decay are used to transform another atomic nucleus. Eventually, in 1932 at Cambridge University, a fully artificial nuclear reaction and nuclear transmutation was achieved by Rutherford's colleagues John Cockcroft and Ernest Walton, who used artificially accelerated protons against lithium-7, to split the nucleus into two alpha particles. The feat was popularly known as "splitting the atom", although it was not the modern nuclear fission reaction later (in 1938) discovered in heavy elements by the German scientists Otto Hahn, Lise Meitner, and Fritz Strassmann. | 0 | Theoretical and Fundamental Chemistry |
Calcineurin (CaN) is a calcium and calmodulin dependent serine/threonine protein phosphatase (also known as protein phosphatase 3, and calcium-dependent serine-threonine phosphatase). It activates the T cells of the immune system and can be blocked by drugs. Calcineurin activates nuclear factor of activated T cell cytoplasmic (NFATc), a transcription factor, by dephosphorylating it. The activated NFATc is then translocated into the nucleus, where it upregulates the expression of interleukin 2 (IL-2), which, in turn, stimulates the growth and differentiation of the T cell response. Calcineurin is the target of a class of drugs called calcineurin inhibitors, which include ciclosporin, voclosporin, pimecrolimus and tacrolimus. | 1 | Applied and Interdisciplinary Chemistry |
China has long been considered the exception to the general use of bloomeries. The Chinese are thought to have skipped the bloomery process completely, starting with the blast furnace and the finery forge to produce wrought iron; by the fifth century BC, metalworkers in the southern state of Wu had invented the blast furnace and the means to both cast iron and to decarburize the carbon-rich pig iron produced in a blast furnace to a low-carbon, wrought iron-like material. Recent evidence, however, shows that bloomeries were used earlier in ancient China, migrating in from the west as early as 800 BC, before being supplanted by the locally developed blast furnace. Supporting this theory was the discovery of "more than ten" iron-digging implements found in the tomb of Duke Jing of Qin (d. 537 BCE), whose tomb is located in Fengxiang County, Shaanxi (a museum exists on the site today). | 1 | Applied and Interdisciplinary Chemistry |
Chemical weapons are said to "make deliberate use of the toxic properties of chemical substances to inflict death". At the start of World War II it was widely reported in newspapers that "entire regions of Europe" would be turned into "lifeless wastelands". However, chemical weapons were not used to the extent predicted by the press.
An unintended chemical weapon release occurred at the port of Bari. A German attack on the evening of December 2, 1943, damaged U.S. vessels in the harbour and the resultant release from their hulls of mustard gas inflicted a total of 628 casualties.
The U.S. Government was highly criticized for exposing American service members to chemical agents while testing the effects of exposure. These tests were often performed without the consent or prior knowledge of the soldiers affected. Australian service personnel were also exposed as a result of the "Brook Island trials" carried out by the British Government to determine the likely consequences of chemical warfare in tropical conditions; little was known of such possibilities at that time.
Some chemical agents are designed to produce mind-altering changes; rendering the victim unable to perform their assigned mission. These are classified as incapacitating agents, and lethality is not a factor of their effectiveness. | 1 | Applied and Interdisciplinary Chemistry |
Dimethyl methylphosphonate can be prepared from trimethyl phosphite and a halomethane (e.g. iodomethane) via the Michaelis–Arbuzov reaction.
Dimethyl methylphosphonate is a schedule 2 chemical as it may be used in the production of chemical weapons. It will react with thionyl chloride to produce methylphosphonic acid dichloride, which is used in the production of sarin and soman nerve agents. Various amines can be used to catalyse this process. It can be used as a sarin-simulant for the calibration of organophosphorus detectors. | 1 | Applied and Interdisciplinary Chemistry |
Degradation begins inside macrophages of the spleen, which remove old and damaged erythrocytes from the circulation.
In the first step, heme is converted to biliverdin by the enzyme heme oxygenase (HO). NADPH is used as the reducing agent, molecular oxygen enters the reaction, carbon monoxide (CO) is produced and the iron is released from the molecule as the ferrous ion (Fe). CO acts as a cellular messenger and functions in vasodilation.
In addition, heme degradation appears to be an evolutionarily-conserved response to oxidative stress. Briefly, when cells are exposed to free radicals, there is a rapid induction of the expression of the stress-responsive heme oxygenase-1 (HMOX1) isoenzyme that catabolizes heme (see below). The reason why cells must increase exponentially their capability to degrade heme in response to oxidative stress remains unclear but this appears to be part of a cytoprotective response that avoids the deleterious effects of free heme. When large amounts of free heme accumulates, the heme detoxification/degradation systems get overwhelmed, enabling heme to exert its damaging effects.
In the second reaction, biliverdin is converted to bilirubin by biliverdin reductase (BVR):
Bilirubin is transported into the liver by facilitated diffusion bound to a protein (serum albumin), where it is conjugated with glucuronic acid to become more water-soluble. The reaction is catalyzed by the enzyme UDP-glucuronosyltransferase.
This form of bilirubin is excreted from the liver in bile. Excretion of bilirubin from liver to biliary canaliculi is an active, energy-dependent and rate-limiting process. The intestinal bacteria deconjugate bilirubin diglucuronide releasing free bilirubin, which can either be reabsorbed or reduced to urobilinogen by the bacterial enzyme bilirubin reductase.
Some urobilinogen is absorbed by intestinal cells and transported into the kidneys and excreted with urine (urobilin, which is the product of oxidation of urobilinogen, and is responsible for the yellow colour of urine). The remainder travels down the digestive tract and is converted to stercobilinogen. This is oxidized to stercobilin, which is excreted and is responsible for the brown color of feces. | 1 | Applied and Interdisciplinary Chemistry |
This timeline of chemistry lists important works, discoveries, ideas, inventions, and experiments that significantly changed humanity's understanding of the modern science known as chemistry, defined as the scientific study of the composition of matter and of its interactions.
Known as "the central science", the study of chemistry is strongly influenced by, and exerts a strong influence on, many other scientific and technological fields. Many historical developments that are considered to have had a significant impact upon our modern understanding of chemistry are also considered to have been key discoveries in such fields as physics, biology, astronomy, geology, and materials science. | 1 | Applied and Interdisciplinary Chemistry |
The mechanistic details of this reaction have been extensively explored by Crich’s laboratories. Low-temperature H, C, and F NMR spectroscopic investigations revealed that anomeric triflate 3 derived from 1 is the intermediate glycosyl donor. Moreover, the mechanism of glycosidic bond forming reaction (3→2) was examined thoroughly by the determination of kinetic isotopic effects (KIEs) and NMR spectroscopy. Consequently, the magnitude of KIEs indicated that the displacement of the triflate from 3 proceeded with the development of significant oxacarbenium ion character at the anomeric position. This might be rationalized either by (1) a dissociative mechanism involving the intermediacy of either a transient contact ion pair (CIP) 4 or a solvent-separated ion pair (SSIP) 5, or (2) a mechanistically variant transition state 7 (Scheme 2).
For the intermediate CIP 4, the triflate anion is closely associated with face where it just departed thus shields that side against nucleophilic attack. For the alternative intermediate SSIP 5 which is in equilibrium with an initial CIP, the anomeric center could presumably be attacked by incoming alcohol from either face, giving β-mannoside 2 along with the undesired α-anomer 6. Along these lines, the presence of the 4,6-O-benzylidene protecting group, which serves to rigidify the pyranoside against rehybridization at the anomeric carbon, is essential in shifting the equilibrium toward the covalent triflate, thus reducing α-glycoside formation. Additionally, the only intermediate observed by NMR spectroscopy is the covalent triflate 3, indicating that the complete set of equilibria between 3, the CIP 4, and SSIP 5 set is very heavily biased towards 3. | 0 | Theoretical and Fundamental Chemistry |
Fluorescent properties in nanodiamonds arise from the presence of nitrogen-vacancy (NV) centers, nitrogen atoms next to a vacancy. Fluorescent nanodiamond (FND) was invented in 2005 and has since been used in various fields of study. The invention received a US patent in 2008 , and a subsequent patent in 2012 . NV centers can be created by irradiating nanodiamonds with high-energy particles (electrons, protons, helium ions), followed by vacuum-annealing at 600–800°C. Irradiation forms vaccines in the diamond structure while vacuum-annealing migrates these vacancies, which will get trapped by nitrogen atoms within the nanodiamond. This process produces two types of NV centers. Two types of NV centers are formed—neutral (NV0) and negatively charged (NV–)—and these have different emission spectra. The NV– the center is of particular interest because it has an S = 1 spin ground state that can be spin-polarized by optical pumping and manipulated using electron paramagnetic resonance. Fluorescent nanodiamonds combine the advantages of semiconductor quantum dots (small size, high photostability, bright multicolor fluorescence) with biocompatibility, non-toxicity, and rich surface chemistry, which means that they have the potential to revolutionize Vivo imaging applications. | 0 | Theoretical and Fundamental Chemistry |
HMG proteins are thought to play a significant role in various human disorders. Disruptions and rearrangements in the genes coding for some of the HMG proteins are associated with some common benign tumors. Antibodies to HMG proteins are found in patients with autoimmune diseases. The SRY gene on the Y Chromosome, responsible for male sexual differentiation, contains an HMG-Box domain. A member of the HMG family of proteins, HMGB1, has also been shown to have an extracellular activity as a chemokine, attracting neutrophils and mononuclear inflammatory cells to the infected liver. The high-mobility group protein such as HMO1 alters DNA architecture by binding, bending and looping. Furthermore, these HMG-box DNA-binding proteins increase the flexibility of the DNA upon binding.
In mammalian cells, the HMG non-histone proteins can modulate the activity of major DNA repair pathways including base excision repair, mismatch repair, nucleotide excision repair and double-strand break repair. | 1 | Applied and Interdisciplinary Chemistry |
Thienamycin (also known as thienpenem) is one of the most potent naturally produced antibiotics known thus far, discovered in Streptomyces cattleya in 1976. Thienamycin has excellent activity against both Gram-positive and Gram-negative bacteria and is resistant to bacterial β-lactamase enzymes. Thienamycin is a zwitterion at pH 7. | 0 | Theoretical and Fundamental Chemistry |
The primary tool for small-scale cupellation was the cupel. Cupels were manufactured in a careful manner. They used to be small vessels shaped in the form of an inverted truncated cone, made of bone ashes. According to Georg Agricola, the best material was obtained from burned antlers of deer, although fish spines could also work. Ashes have to be ground into a fine and homogeneous powder and mixed with some sticky substance to mould the cupels. Moulds were made out of copper with no bottoms, so that the cupels could be taken off. A shallow depression in the centre of the cupel was made with a rounded pestle. Cupel sizes depend on the amount of material to be assayed. This same shape has been maintained until the present.
Archaeological investigations as well as archaeometallurgical analysis and written texts from the Renaissance have demonstrated the existence of different materials for their manufacture; they could be made also with mixtures of bones and wood ashes, of poor quality, or moulded with a mixture of this kind in the bottom with an upper layer of bone ashes. Different recipes depend on the expertise of the assayer or on the special purpose for which it was made (assays for minting, jewelry, testing purity of recycled material or coins). Archaeological evidence shows that at the beginnings of small-scale cupellation, potsherds or clay cupels were used. | 1 | Applied and Interdisciplinary Chemistry |
Promoters can be very closely located in the DNA. Such "closely spaced promoters" have been observed in the DNAs of all life forms, from humans to prokaryotes and are highly conserved. Therefore, they may provide some (presently unknown) advantages.
These pairs of promoters can be positioned in divergent, tandem, and convergent directions. They can also be regulated by transcription factors and differ in various features, such as the nucleotide distance between them, the two promoter strengths, etc.
The most important aspect of two closely spaced promoters is that they will, most likely, interfere with each other. Several studies have explored this using both analytical and stochastic models. There are also studies that measured gene expression in synthetic genes or from one to a few genes controlled by bidirectional promoters.
More recently, one study measured most genes controlled by tandem promoters in E. coli. In that study, it was measured and then modeled two main forms of interference. One is when an RNAP is on the downstream promoter, blocking the movement of RNAPs elongating from the upstream promoter. The other is when the two promoters are so close that when an RNAP sits on one of the promoters, it blocks any other RNAP from reaching the other promoter. These events are possible because the RNAP occupies several nucleotides when bound to the DNA, including in transcription start sites.
Similar events occur when the promoters are in divergent and convergent formations. The possible events also depend on the distance between them. | 1 | Applied and Interdisciplinary Chemistry |
The most common method of teaching chemistry is lecture with a laboratory component. Laboratory courses became a central part of the chemistry curriculum towards the end of the 19th century. The German scientist Justus von Liebig plays a major role in shifting the model of lecture with demonstrations to one that includes a laboratory component. Liebig was one of the first chemists to conduct a laboratory and his methodology became widespread in the United States due to the efforts of Eben Horsford and Charles W. Eliot. After working in Liebigs laboratory, Horsford returned to the United States and helped establish the Lawrence Scientific School at Harvard University. The school was modeled after Liebigs methodology and established the first chemistry laboratory course. Two years later, Charles W. Eliot started to volunteer at the laboratory. Eliots interests in the laboratory grew, and he eventually took charge of it. Eliot was later elected as Harvards president in 1869. Eliot also served other powerful roles in education, which allowed him to influence the widespread adoption of laboratory methods. Today, the American Chemical Society on Professional Training requires students to gain 400 hours of laboratory experience, outside of introductory chemistry, to get a bachelors degree. Similarly, the Royal Society of Chemistry requires students to gain 300 hours of laboratory experience to get a bachelors degree.
However, since the twenty-first century, the role of laboratory courses in the chemistry curriculum has been questioned in major journals. The main argument against laboratory courses is that there is little evidence for their impact on student learning. Researchers are asking questions such as "why do we have laboratory work in the curriculum? What is distinctive about laboratory work that cannot be met elsewhere in the curriculum?" Researchers are asking for evidence that the investment of space, time and resources in chemistry laboratories provides value to student learning. | 1 | Applied and Interdisciplinary Chemistry |
EngineAir, an Australian company, is making a rotary engine powered by compressed air, called The Di Pietro motor.
The Di Pietro motor concept is based on a rotary piston. Different from existing rotary engines, the Di Pietro motor uses a simple cylindrical rotary piston (shaft driver) which rolls, with little friction, inside the cylindrical stator.
It can be used in boats, cars, burden carriers and other vehicles. Only 1 psi (≈ 6,8 kPa) of pressure is needed to overcome the friction. The engine was also featured on the ABC's New Inventors programme in Australia on 24 March 2004. | 1 | Applied and Interdisciplinary Chemistry |
Dippel's oil (sometimes referred to as bone oil) is a nitrogenous by-product of the destructive distillation of bones. A dark, viscous, tar-like liquid with an unpleasant smell, it is named after its inventor, Johann Konrad Dippel. The oil consists of aliphatic chains, with nitrogen functional groups including pyrroles, pyridines and nitriles, as well as other nitrogenous compounds.
Dippel's oil had a number of uses, which are mostly obsolete. Its primary use was as an animal and insect repellent. It saw limited use as a chemical warfare harassing agent during the desert campaign of World War II. The oil was used to render wells undrinkable and thus deny their use to the enemy.
By not being lethal, the oil was claimed to not be in breach of the Geneva Protocol. | 0 | Theoretical and Fundamental Chemistry |
Chronic solvent exposures are often caused by the inhalation of solvent vapors, or the ingestion of diluted solvents, repeated over the course of an extended period.
Some solvents can damage internal organs like the liver, the kidneys, the nervous system, or the brain. The cumulative brain effects of long-term or repeated exposure to some solvents is called chronic solvent-induced encephalopathy (CSE).
Chronic exposure to organic solvents in the work environment can produce a range of adverse neuropsychiatric effects. For example, occupational exposure to organic solvents has been associated with higher numbers of painters suffering from alcoholism. Ethanol has a synergistic effect when taken in combination with many solvents; for instance, a combination of toluene/benzene and ethanol causes greater nausea/vomiting than either substance alone.
Some organic solvents are known or suspected to be cataractogenic. A mixture of aromatic hydrocarbons, aliphatic hydrocarbons, alcohols, esters, ketones, and terpenes were found to greatly increase the risk of developing cataracts in the lens of the eye. | 1 | Applied and Interdisciplinary Chemistry |
The model of ionic atmosphere is less adequate for concentrated ionic solutions near saturation. These solutions as well as molten salts or ionic liquids have a structure similar to the crystalline lattice where water molecules are located between ions. | 0 | Theoretical and Fundamental Chemistry |
Physical exercise rapidly triggers substantial changes at the organismal level, including the secretion of myokines and metabolites by muscle cells. For instance, aerobic exercise in humans leads to significant structural alterations in the brain, while wheel-running in rodents promotes neurogenesis and improves synaptic transmission in particular in the hippocampus. Moreover, physical exercise triggers histone modifications and protein synthesis which ultimately positively influence mood and cognitive abilities. Notably, regular exercise is somewhat associated with a better sleep quality, which could be mediated by the muscle secretome. | 1 | Applied and Interdisciplinary Chemistry |
Laser diffraction analysis has been questioned in validity in the following areas:
* assumptions including particles having random configurations and volume values. In some dispersion units, particles have been shown to align themselves together rather than have a turbulent flow, causing them to lead themselves in an orderly direction.
* algorithms used in laser diffraction analysis are not thoroughly validated. Different algorithms are used at times to have collected data match assumptions made by users as an attempt to avoid data that looks incorrect.
* measurement inaccuracies due to sharp edges on objects. Laser diffraction analysis has the chance of detecting imaginary particles at sharp edges because of the large angles the lasers make upon them.
* when compared to the data collecting of optical imaging, another particle-sizing technique, correlation between the two was poor for non-spherical particles. This is due to the fact that the underlying Fraunhofer and Mie theories only cover spherical particles. Non-spherical particles cause more diffuse scatter patterns and are more difficult to interpret. Some manufacturers have included algorithms in their software, which can partly compensate for non-spherical particles. | 0 | Theoretical and Fundamental Chemistry |
For virus-associated tumors, such as cervical cancer and a subset of head and neck cancers, epitopes derived from viral open reading frames contribute to the pool of neoantigens. | 1 | Applied and Interdisciplinary Chemistry |
Two GGPP molecules condense via phytoene synthase (PSY), forming the 15-cis isomer of phytoene. PSY belongs to the squalene/phytoene synthase family and is homologous to squalene synthase that takes part in steroid biosynthesis. The subsequent conversion of phytoene into all-trans-lycopene depends on the organism. Bacteria and fungi employ a single enzyme, the bacterial phytoene desaturase (CRTI) for the catalysis. Plants and cyanobacteria however utilize four enzymes for this process. The first of these enzymes is a plant-type phytoene desaturase which introduces two additional double bonds into 15-cis-phytoene by dehydrogenation and isomerizes two of its existing double bonds from trans to cis producing 9,15,9’-tri-cis-ζ-carotene. The central double bond of this tri-cis-ζ-carotene is isomerized by the zeta-carotene isomerase Z-ISO and the resulting 9,9'-di-cis-ζ-carotene is dehydrogenated again via a ζ-carotene desaturase (ZDS). This again introduces two double bonds, resulting in 7,9,7’,9’-tetra-cis-lycopene. CRTISO, a carotenoid isomerase, is needed to convert the cis-lycopene into an all-trans lycopene in the presence of reduced FAD.
This all-trans lycopene is cyclized; cyclization gives rise to carotenoid diversity, which can be distinguished based on the end groups. There can be either a beta ring or an epsilon ring, each generated by a different enzyme (lycopene beta-cyclase [beta-LCY] or lycopene epsilon-cyclase [epsilon-LCY]). α-Carotene is produced when the all-trans lycopene first undergoes reaction with epsilon-LCY then a second reaction with beta-LCY; whereas β-carotene is produced by two reactions with beta-LCY. α- and β-Carotene are the most common carotenoids in the plant photosystems but they can still be further converted into xanthophylls by using beta-hydrolase and epsilon-hydrolase, leading to a variety of xanthophylls. | 0 | Theoretical and Fundamental Chemistry |
During the 2000s, inflatables have replaced the plastic blow-molded yard decorations used as Christmas decorations at many U.S. homes, and are also now used as Halloween decorations and for other occasions as well.
These are made of a synthetic fabric, of which different colors have been sewn together in various patterns. An electric blower constantly forces air into the figure, replacing air lost through its fabric and seams. They are internally lit by small C7 incandescent light bulbs (also used in nightlights), which are covered by translucent plastic snap-on globes that protect the fabric from the heat if they should rest against it.
Inflatables come in various sizes, commonly four feet or 1.2 meters tall (operated with a low-voltage DC power supply and a computer fan), and six or eight feet (1.8 to 2.4 meters) tall, running directly from AC mains electricity. Like inflatable rides, outdoor types are staked to the ground with guy wires (usually synthetic rope or flat straps) to keep them upright in the wind, though being rather flimsy this does not always work. Heavy snow or rainwater which has accumulated may also prevent proper inflation.
While these store compactly, there are disadvantages, including the large amount of electricity needed to constantly keep them inflated. While they can be turned off in the daytime, this leaves the figure deflated, and subject to the rain and snow problem. Freezing rain, heavy snow, or high winds may also cause inflatables to collapse. Additionally, like a tent, they must be completely dry before being packed for storage, or mildew may be a problem (especially if kept in a basement).
Decorative inflatables can be mended using duct tape or rip stock patching tape. Since these materials are now available in colors, matching the patch to the inflatable is not difficult.
Decorative inflatables are made in many popular characters, including Santa Claus and snowmen for Christmas, and ghosts and jack-o-lanterns for Halloween. Several trademarked characters are also produced, including SpongeBob SquarePants, Winnie the Pooh, and Snoopy and Woodstock from Peanuts. There are also walk-through arches and "haunted houses" for children, and items for other holidays like Uncle Sam for Independence Day, and palm trees for backyard summer cookouts.
Since 2005, there are also inflatable snow globes which blow tiny styrofoam beads around on the inside, the blower's air jet picking them up and through a tube to the top, where they fall down inside the clear vinyl front. On others, mainly for Halloween, lightweight foam bats or ghosts spin around like confetti in what is called a "tornado globe". The figures inside both types are also inflatables.
Since 2006, several of these have motion, which is driven by the air itself and the Venturi effect. The original is a merry-go-round (usually surrounded by clear vinyl for support), another from 2007 is an airplane with moving propeller. Ghosts may also have streamers which blow around where the air escapes.
Inflatables have been made by visual artists and displayed in prominent places in Australia, including on the water in Sydney Harbor and in the sky over the city of Canberra. Examples include Alphie the Alpha Turtle and Patricia Piccininis The Skywhale'. | 1 | Applied and Interdisciplinary Chemistry |
The IsoRes hypothesis has been tested experimentally by means of growth of E. coli and found to be supported by extremely strong statistics (p ). Particular strong evidence of faster growth was found for the “super-resonance”.
Fig. 1. 2D plot of molecular masses of 3000 E. coli tryptic peptides. A – terrestrial isotopic compositions (red arrow shows the line representing the resonance); B – O abundance is increased by 20%, which destroyed the terrestrial resonance; C – isotopic compositions of the “super-resonance”, where all dots (molecules) are perfectly aligned. Adapted from ref. 4. | 0 | Theoretical and Fundamental Chemistry |
The pan amalgamation process is a method to extract silver from ore, using salt and copper(II) sulfate in addition to mercury. The process was widely used from 1609 through the 19th century; it is no longer used.
The patio process had been used to extract silver from ore since its invention in 1557. One drawback of the patio process was the long treatment time, usually weeks. Alvaro Alonso Barba invented the faster pan process (in Spanish the cazo or fondo process) in 1609 in Potosí, Bolivia, in which ore was mixed with salt and mercury (and sometimes copper(II) sulfate) and heated in shallow copper vessels. The treatment time was reduced to 10 to 20 hours. Whether patio or pan amalgamation was used at a particular location often depended on climate (warmer conditions speeded the patio process) and the availability and cost of fuel to heat the pans.
The amount of salt and copper(II) sulfate varied from one-quarter to ten pounds of one or the other, or both, per ton of ore treated. The loss of mercury in amalgamation processes was generally one to two times the weight of silver recovered. | 1 | Applied and Interdisciplinary Chemistry |
Transition-metal-catalyzed
cascade sequences combine the novelty and power of organometallic chemistry
with the synthetic utility and economy of cascade reactions, providing an even
more ecologically and economically desirable approach to organic synthesis.
For instance, rhodium catalysis was used to convert acyclic monoterpenes of the
type 59 to 4H-chromen products in a hydroformylation cascade (Scheme 12). First, selective rhodium-catalyzed
hydroformylation of the less sterically hindered olefin bond in 59 yielded unsaturated aldehyde 60, which under the same conditions was
then converted to intermediate 61
via a carbonyl-ene reaction. A second rhodium-catalyzed hydroformylation to
species 62 was followed by
condensation to form 4H-chromen
products of the type 63 in 40%
overall yield.
Rhodium catalysis was also employed to initiate a cyclization/cycloaddition cascade in
the synthesis of a tigliane reported by the Dauben group (Scheme 13). Treatment of diazoimide 64 with rhodium(II) acetate dimer generated
a carbenoid that yielded reactive ylide 65
after an intramolecular cyclization with the neighboring carbonyl group. An
intramolecular [3+2] cycloaddition then spontaneously occurred to afford the
target tigliane 66.
The formal intramolecular [4+2]
cycloaddition of 1,6-enynes of the type 67
mediated by gold catalysis is another example of a transition-metal-catalyzed
cascade (Scheme 14). A variety of
1,6-enynes reacted under mild conditions in the presence of Au(I) complexes 68a–b to yield the tricyclic products 69 in moderate to excellent yields.
This formal cycloaddition was proposed
to proceed via the cascade process shown in Scheme 15. Complexation of the 1,6-enyne
67 with the cationic form of the
catalyst yields intermediate 70, in
which the activated triple bond is attacked by the olefin functionality to
yield substituted cyclopropane 71. Electrophilic
opening of the three-membered ring forms cationic species 72, which undergoes a Friedel-Crafts-type reaction and then
rearomatizes to give tricyclic product 69. Due to the nature of
the interaction of gold complexes with unsaturated systems, this process could
also be considered an electrophilic cascade.
An example of palladium-catalyzed
cascades is represented by the asymmetric polyene Heck cyclization used in the preparation
of (+)-xestoquinone from triflate substrate 75 (Scheme 16). Oxidative addition of the aryl–triflate bond
into the palladium(0) complex in the presence of chiral diphosphine ligand (S)-binap yields chiral palladium(II)
complex 77. This step is followed by
the dissociation of the triflate anion, association of the neighboring olefin
and 1,2-insertion of the naphthyl group into the olefin to yield intermediate 79. A second migratory insertion into
the remaining olefin group followed by a β-elimination
then occurs to afford product 81 in
82% overall yield and with moderate enantioselectivity. The palladium(0)
catalyst is also regenerated in this step, thus allowing the cascade to be reinitiated. | 0 | Theoretical and Fundamental Chemistry |
Archaea have a preinitiation complex resembling that of a minimized Pol II PIC, with a TBP and an Archaeal transcription factor B (TFB, a TFIIB homolog). The assembly follows a similar sequence, starting with TBP binding to the promoter. An interesting aspect is that the entire complex is bound in an inverse orientation compared to those found in eukaryotic PIC. They also use TFE, a TFIIE homolog, which assists in transcription initiation but is not required. | 1 | Applied and Interdisciplinary Chemistry |
A nucleic acid sequence is a succession of bases within the nucleotides forming alleles within a DNA (using GACT) or RNA (GACU) molecule. This succession is denoted by a series of a set of five different letters that indicate the order of the nucleotides. By convention, sequences are usually presented from the 5 end to the 3 end. For DNA, with its double helix, there are two possible directions for the notated sequence; of these two, the sense strand is used. Because nucleic acids are normally linear (unbranched) polymers, specifying the sequence is equivalent to defining the covalent structure of the entire molecule. For this reason, the nucleic acid sequence is also termed the primary structure.
The sequence represents genetic information. Biological deoxyribonucleic acid represents the information which directs the functions of an organism.
Nucleic acids also have a secondary structure and tertiary structure. Primary structure is sometimes mistakenly referred to as "primary sequence". However there is no parallel concept of secondary or tertiary sequence. | 1 | Applied and Interdisciplinary Chemistry |
In a magnetized, perfectly conducting fluid, the magnetic forces behave in some very important respects as though the elements of fluid were connected with elastic bands: trying to displace such an element perpendicular to a magnetic line of force causes an attractive force proportional to the displacement, like a spring under tension. Normally, such a force is restoring, a strongly stabilizing influence that would allow a type of magnetic wave to propagate. If the fluid medium is not stationary but rotating, however, attractive forces can actually be destabilizing. The MRI is a consequence of this surprising behavior.
Consider, for example, two masses, m ("inner") and m ("outer") connected by a spring under tension, both masses in orbit around a central body, M. In such a system, the angular velocity of circular orbits near the center is greater than the angular velocity of orbits farther from the center, but the angular momentum of the inner orbits is smaller than that of the outer orbits. If m is allowed to orbit a little bit closer to the center than m, it will have a slightly higher angular velocity. The connecting spring will pull back on m, and drag m forward. This means that m experiences a retarding torque, loses angular momentum, and must fall inward to an orbit of smaller radius, corresponding to a smaller angular momentum. m, on the other hand, experiences a positive torque, acquires more angular momentum, and moves outward to a higher orbit. The spring stretches yet more, the torques become yet larger, and the motion is unstable! Because magnetic forces act like a spring under tension connecting fluid elements, the behavior of a magnetized fluid is almost exactly analogous to this simple mechanical system. This is the essence of the MRI . | 1 | Applied and Interdisciplinary Chemistry |
Cross-vanes are U-shaped structures made of boulders or logs, built across the channel to concentrate stream flow in the center of the channel and thereby reduce bank erosion. They do not impact channel capacity and provides other benefits such as improved habitat for aquatic species. Similar structures used to dissipate stream energy include the W-weirs and J-Hook vanes. | 1 | Applied and Interdisciplinary Chemistry |
Alain Berton was awarded the Medal of the International Bureau of Analytical Chemistry (BICA)- International fight against chemical weapons. led by :fr:Paul Nicolardot. | 0 | Theoretical and Fundamental Chemistry |
*[https://bitbucket.org/philip_cardiff/solids4foam-release/src/master/solids4foam solids4Foam], a toolbox for OpenFOAM with capabilities for solid mechanics and fluid solid interactions
*[http://www.oomph-lib.org/ oomph-lib]
*[https://web.archive.org/web/20081203094902/http://www.csc.fi/english/pages/elmer/examples/Coupled_problems/hemodyn Elmer FSI page]
* [https://launchpad.net/cbc.solve/ CBC.solve Biomedical Solvers]
* [http://www.precice.org preCICE Coupling Library]
* [https://www.sphinxsys.org/ SPHinXsys multi-physics library] It provides C++ APIs for physical accurate simulation and aims to model coupled industrial dynamic systems including fluid, solid, multi-body dynamics and beyond with SPH (smoothed particle hydrodynamics), a meshless computational method using particle discretization. | 1 | Applied and Interdisciplinary Chemistry |
Gene Map Annotator and Pathway Profiler (GenMAPP) a free, open-source, stand-alone computer program is designed for organizing, analyzing, and sharing genome scale data in the context of biological pathways. GenMAPP database support multiple gene annotations and species as well as custom species database creation for a potentially unlimited number of species. Pathway resources are expanded by utilizing homology information to translate pathway content between species and extending existing pathways with data derived from conserved protein interactions and coexpression. A new mode of data visualization including time-course, single nucleotide polymorphism (SNP), and splicing, has been implemented with GenMAPP database to support analysis of complex data. GenMAPP also offers innovative ways to display and share data by incorporating HTML export of analyses for entire sets of pathways as organized web pages. In short, GenMAPP provides a means to rapidly interrogate complex experimental data for pathway-level changes in a diverse range of organisms. | 0 | Theoretical and Fundamental Chemistry |
To date there are more than 300 known coregulators. Some examples of these coactivators include:
* ARA54 targets androgen receptors
* ATXN7L3 targets several members of the nuclear receptor superfamily
* BCL3 targets 9-cis retinoic acid receptor (RXR)
* CBP targets many transcription factors
* CDC25B targets steroid receptors
* COPS5 targets several nuclear receptors
* DDC targets androgen receptors
* EP300 targets many transcription factors
* KAT5 targets many nuclear receptors
* KDM1A targets androgen receptors
* Steroid receptor coactivator (SRC) family
** NCOA1 targets several members of the nuclear receptor superfamily
** NCOA2 targets several members of the nuclear receptor superfamily
** NCOA3 targets several nuclear receptors and transcription factors
* YAP targets transcription factors
* WWTR1 targets transcription factors | 1 | Applied and Interdisciplinary Chemistry |
Segrè was appointed assistant professor of physics at the University of Rome in 1932 and worked there until 1936, becoming one of the Via Panisperna boys. In 1934, he met Elfriede Spiro, a Jewish woman whose family had come from Ostrowo in West Prussia, but had fled to Breslau when that part of Prussia became part of Poland after World War I. After the Nazi Party came to power in Germany in 1933, she had emigrated to Italy, where she worked as a secretary and an interpreter. At first she did not speak Italian well, and Segrè and Spiro conversed in German, in which he was fluent. The two were married at the Great Synagogue of Rome on 2 February 1936. He agreed with the rabbi to spend the minimal amount on the wedding, giving the balance of what would be spent on a luxury wedding to Jewish refugees from Germany. The rabbi managed to give them many of the trappings of a luxury wedding anyway. The couple had three children: Claudio, born in 1937, Amelia Gertrude Allegra, born in 1937, and Fausta Irene, born in 1945.
After marrying, Segrè sought a stable job and became professor of physics and director of the Physics Institute at the University of Palermo. He found the equipment there primitive and the library bereft of modern physics literature, but his colleagues at Palermo included the mathematicians Michele Cipolla and Michele De Franchis, the mineralogist Carlo Perrier and the botanist . In 1936 he paid a visit to Ernest O. Lawrences Berkeley Radiation Laboratory, where he met Edwin McMillan, Donald Cooksey, Franz Kurie, Philip Abelson and Robert Oppenheimer. Segrè was intrigued by the radioactive scrap metal that had once been part of the laboratorys cyclotron. In Palermo, this was found to contain a number of radioactive isotopes. In February 1937, Lawrence sent him a molybdenum strip that was emitting anomalous forms of radioactivity. Segrè enlisted Perrier's help to subject the strip to careful chemical and theoretical analysis, and they were able to prove that some of the radiation was being produced by a previously unknown element. In 1947 they named it technetium, as it was the first artificially synthesized chemical element. | 1 | Applied and Interdisciplinary Chemistry |
A number of factors can affect the migration of nucleic acids: the dimension of the gel pores, the voltage used, the ionic strength of the buffer, and the concentration intercalating dye such as ethidium bromide if used during electrophoresis. | 1 | Applied and Interdisciplinary Chemistry |
A similar process (environmental stress cracking) occurs in polymers, when products are exposed to specific solvents or aggressive chemicals such as acids and alkalis. As with metals, attack is confined to specific polymers and particular chemicals. Thus polycarbonate is sensitive to attack by alkalis, but not by acids. On the other hand, polyesters are readily degraded by acids, and SCC is a likely failure mechanism. Polymers are susceptible to environmental stress cracking where attacking agents do not necessarily degrade the materials chemically.
Nylon is sensitive to degradation by acids, a process known as hydrolysis, and nylon mouldings will crack when attacked by strong acids.
For example, the fracture surface of a fuel connector showed the progressive growth of the crack from acid attack (Ch) to the final cusp (C) of polymer. In this case the failure was caused by hydrolysis of the polymer by contact with sulfuric acid leaking from a car battery. The degradation reaction is the reverse of the synthesis reaction of the polymer:
Cracks can be formed in many different elastomers by ozone attack, another form of SCC in polymers. Tiny traces of the gas in the air will attack double bonds in rubber chains, with natural rubber, styrene-butadiene rubber, and nitrile butadiene rubber being most sensitive to degradation. Ozone cracks form in products under tension, but the critical strain is very small. The cracks are always oriented at right angles to the strain axis, so will form around the circumference in a rubber tube bent over. Such cracks are dangerous when they occur in fuel pipes because the cracks will grow from the outside exposed surfaces into the bore of the pipe, so fuel leakage and fire may follow. Ozone cracking can be prevented by adding anti-ozonants to the rubber before vulcanization. Ozone cracks were commonly seen in automobile tire sidewalls, but are now seen rarely thanks to the use of these additives. On the other hand, the problem does recur in unprotected products such as rubber tubing and seals. | 1 | Applied and Interdisciplinary Chemistry |
A type Ia supernova results from runaway carbon fusion in the core of a carbon-oxygen white dwarf star. If a white dwarf, which is composed almost entirely of degenerate matter, can gain mass from a companion, the increasing temperature and density of material in its core will ignite carbon fusion if the star's mass approaches the Chandrasekhar limit. This leads to an explosion that completely disrupts the star. Luminosity increases by a factor of greater than 5 billion. One way to gain the additional mass would be by accreting gas from a giant star (or even main sequence) companion. A second and apparently more common mechanism to generate the same type of explosion is the merger of two white dwarfs. | 1 | Applied and Interdisciplinary Chemistry |
Methanol is a fuel for heat engines and fuel cells. Due to its high octane rating it can be used directly as a fuel in flex-fuel cars (including hybrid and plug-in hybrid vehicles) using existing internal combustion engines (ICE). Methanol can also be burned in some other kinds of engine or to provide heat as other liquid fuels are used. Fuel cells, can use methanol either directly in Direct Methanol Fuel Cells (DMFC) or indirectly (after conversion into hydrogen by reforming) in a Reformed Methanol Fuel Cell (RMFC). | 1 | Applied and Interdisciplinary Chemistry |
Identification of the blockage positions of the hairpin produced by the hybridization of the discriminating nucleotides can be observed as the pauses in the time course of the hairpin distance measurement. The complete sequence can be reconstructed by the overlapping fragments. | 1 | Applied and Interdisciplinary Chemistry |
In 1964 he joined the United Kingdom Atomic Energy Authority. In 1966 he obtained a research assistant post at the Nottingham and District Technical College where he began his research on particle technology. In 1969 he moved to the chemical engineering department of Loughborough University of Technology.
He stayed there until 1983 when he moved to Delft University of Technology as a full professor, of chemical technology in the Departments of chemical engineering, mechanical engineering and mining. In 2000 he moved to the University of Florida as full professor in the National Science Foundation Engineering Research Centre, in particle science and technology, forming the largest academic group in powder mechanics in the US. He continued there until his death. | 1 | Applied and Interdisciplinary Chemistry |
Although Jaffes name is synonymous with clinical creatinine testing, his paper only described the principle behind what would later become the enduring method. It was Otto Folin (1867–1934), a Harvard biochemist, who adapted Jaffes research—abandoning the standard Neubauer reaction of the time—and published several papers using the Jaffe reaction to analyze creatinine levels in both blood and urine. Folin began using the picric acid procedure in 1901 and included it in his 1916 Lab Manual of Biological Chemistry. During his career, Folin modified and improved several quantitative colorimetric procedures, the first of which was for creatinine. He took advantage of technology available at the time, using a Duboscq colorimeter for measurement precision, and is credited for introducing colorimetry into modern biochemical analysis.
Folin's research did not focus on creatinine as a renal function indicator. Since the precursors of creatinine are synthesized in the liver, at this point in history, creatinine was considered indicative of liver function. It was not until 1926 that Poul Kristian Brandt Rehberg suggested creatinine was a significant marker for renal function. | 1 | Applied and Interdisciplinary Chemistry |
The form the equation is written in is not entirely clear due to different definitions for . This term can be found defined as or its transpose (for example see Strain-rate_tensor containing both). Changing this definition only necessitates changes in transpose operations and is thus largely inconsequential and can be done as long as one stays consistent. The notation used here is picked to be consistent with the literature using the upper-convected derivative. | 1 | Applied and Interdisciplinary Chemistry |
While many of the proteins involved in NMD are not conserved between species, in Saccharomyces cerevisiae (yeast), there are three main factors in NMD: UPF1, UPF2 and UPF3 (UPF3A and UPF3B in humans), that make up the conserved core of the NMD pathway. All three of these factors are trans-acting elements called up-frameshift (UPF) proteins. In mammals, UPF2 and UPF3 are part of the exon-exon junction complex (EJC) bound to mRNA after splicing along with other proteins, eIF4AIII, MLN51, and the Y14/MAGOH heterodimer, which also function in NMD. UPF1 phosphorylation is controlled by the proteins SMG-1, SMG-5, SMG-6 and SMG-7.
The process of detecting aberrant transcripts occurs during translation of the mRNA. A popular model for the detection of aberrant transcripts in mammals suggests that during the first round of translation, the ribosome removes the exon-exon junction complexes bound to the mRNA after splicing occurs. If after this first round of translation, any of these proteins remain bound to the mRNA, NMD is activated. Exon-exon junction complexes located downstream of a stop codon are not removed from the transcript because the ribosome is released before reaching them. Termination of translation leads to the assembly of a complex composed of UPF1, SMG1 and the release factors, eRF1 and eRF3, on the mRNA. If an EJC is left on the mRNA because the transcript contains a premature stop codon, then UPF1 comes into contact with UPF2 and UPF3, triggering the phosphorylation of UPF1. In vertebrates, the location of the last exon-junction complex relative to the termination codon usually determines whether the transcript will be subjected to NMD or not. If the termination codon is downstream of or within about 50 nucleotides of the final exon-junction complex then the transcript is translated normally. However, if the termination codon is further than about 50 nucleotides upstream of any exon-junction complexes, then the transcript is down regulated by NMD. The phosphorylated UPF1 then interacts with SMG-5, SMG-6 and SMG-7, which promote the dephosphorylation of UPF1. SMG-7 is thought to be the terminating effector in NMD, as it accumulates in P-bodies, which are cytoplasmic sites for mRNA decay. In both yeast and human cells, the major pathway for mRNA decay is initiated by the removal of the 5’ cap followed by degradation by XRN1, an exoribonuclease enzyme. The other pathway by which mRNA is degraded is by deadenylation from 3’-5'.
In addition to the well recognized role of NMD in removing aberrant transcripts, there are transcripts that contain introns within their 3'UTRs. These messages are predicted to be NMD-targets yet they (e.g., activity-regulated cytoskeleton-associated protein, known as Arc) can play crucial biologic functions suggesting that NMD may have physiologically relevant roles. | 1 | Applied and Interdisciplinary Chemistry |
Some fission products decay with the release of delayed neutrons, important to nuclear reactor control.
Other fission products, such as xenon-135 and samarium-149, have a high neutron absorption cross section. Since a nuclear reactor must balance neutron production and absorption rates, fission products that absorb neutrons tend to "poison" or shut the reactor down; this is controlled with burnable poisons and control rods. Build-up of xenon-135 during shutdown or low-power operation may poison the reactor enough to impede restart or interfere with normal control of the reaction during restart or restoration of full power. This played a major role in the Chernobyl disaster. | 0 | Theoretical and Fundamental Chemistry |
A proposal regarding the interlinking of rivers in India has a long history. During the British colonial rule, for example, the 19th century engineer Arthur Cotton proposed the plan to interlink major Indian rivers in order to hasten import and export of goods from its colony in South Asia, as well as to address water shortages and droughts in southeastern India, now Andhra Pradesh and Odisha. | 1 | Applied and Interdisciplinary Chemistry |
Research on paracrine signaling through the JAK-STAT pathway revealed its potential in activating invasive behavior of ovarian epithelial cells. This epithelial to mesenchymal transition is highly evident in metastasis. Paracrine signaling through the JAK-STAT pathway is necessary in the transition from stationary epithelial cells to mobile mesenchymal cells, which are capable of invading surrounding tissue. Only the JAK-STAT pathway has been found to induce migratory cells. | 1 | Applied and Interdisciplinary Chemistry |
A fire requires heat, fuel, and an oxidizing agent. The energy required to overcome the activation energy barrier for combustion is transferred as heat into the system, resulting in changes to the systems internal energy. In a process, the energy input to start a fire may comprise both work and heat, such as when one rubs tinder (work) and experiences friction (heat) to start a fire. The ensuing combustion is highly exothermic, which releases heat. The overall change in internal energy does not reveal the mode of energy transfer and quantifies only the net work and heat. The difference between initial and final states of the systems internal energy does not account for the extent of the energy interactions transpired. Therefore, internal energy is a state function (i.e. exact differential), while heat and work are path functions (i.e. inexact differentials) because integration must account for the path taken. | 0 | Theoretical and Fundamental Chemistry |
Thermoclines are often associated with chlorophyll maximum layers. Internal waves represent oscillations of these thermoclines and therefore have the potential to transfer these phytoplankton rich waters downward, coupling benthic and pelagic systems. Areas affected by these events show higher growth rates of suspension feeding ascidians and bryozoans, likely due to the periodic influx of high phytoplankton concentrations. Periodic depression of the thermocline and associated downwelling may also play an important role in the vertical transport of planktonic larvae. | 1 | Applied and Interdisciplinary Chemistry |
Radiosynthesis is the theorized capture and metabolism, by living organisms, of energy from ionizing radiation, analogously to photosynthesis. Metabolism of ionizing radiation was theorized as early as 1956 by the Russian microbiologist S. I. Kuznetsov.
Beginning in the 1990s, researchers at the Chernobyl Nuclear Power Plant uncovered some 200 species of apparently radiotrophic fungi containing the pigment melanin on the walls of the reactor room and in the surrounding soil. Such "melanized" fungi have also been discovered in nutrient-poor, high-altitude areas which are exposed to high levels of ultraviolet radiation.
Following the Russian results, an American team at the Albert Einstein College of Medicine of Yeshiva University in New York began experimenting with radiation exposure of melanin and melanized fungi. They found that ionizing radiation increased the ability of melanin to support an important metabolic reaction, and that Cryptococcus neoformans fungi grew three times faster than normal. Microbiologist Ekaterina Dadachova suggested such fungi could serve as a food supply and source of radiation protection for interplanetary astronauts, who would be exposed to cosmic rays.
In 2014, the American research group was awarded a patent for a method of enhancing the growth of microorganisms through increasing melanin content. The inventors of this process claimed their fungi were employing radiosynthesis, and hypothesized that radiosynthesis may have played a role in early life on Earth, by allowing melanized fungi to act as autotrophs.
From October 2018 through March 2019, NASA conducted an experiment aboard the International Space Station to study radiotrophic fungi as a potential radiation barrier to the harmful radiation in space. Radiotrophic fungi have many possible applications on Earth as well, potentially including a disposal method for nuclear waste or use as high-altitude biofuel or a nutrition source. | 0 | Theoretical and Fundamental Chemistry |
In acid–base chemistry, homoassociation (an IUPAC term) is an association between a base and its conjugate acid through a hydrogen bond. The alternate term homoconjugation also has wide usage, but is ambiguous because it has another meaning in organic chemistry (see Conjugated system#Mechanism).
Most commonly, homoassociation leads to the enhancement of the acidity of an acid by itself. The effect is accentuated at high concentrations, i.e. the ionization of an acid varies nonlinearly with concentration. This effect arises from the stabilization of the conjugate base by its formation of a hydrogen bond to the parent acid. A well known case is hydrofluoric acid, which is a significantly stronger acid when concentrated than when dilute due to the following equilibria:
:2 HF HF + F (autoionization of HF)
:HF + F HF (homoassociation)
Overall:
:3 HF HF + HF
The bifluoride anion (HF) encourages the ionization of HF by stabilizing the F. Thus, the usual ionization constant for hydrofluoric acid (10) understates the acidity of concentrated solutions of HF.
The effect of homoassociation is often high in nonaqueous solutions, wherein dissociation is often low. Carboxylic acids and phenols exhibit this effect, for example in sodium diacetate. | 0 | Theoretical and Fundamental Chemistry |
Glyoxalase I (GLO1), glyoxalase II (GLO2), and reduced glutathione (GSH). In bacteria, there is an additional enzyme that functions if there is no GSH, it is called the third glyoxalase protein, glyoxalase 3 (GLO3). GLO3 has not been found in humans yet.
The pathway begins with methylglyoxal (MG), which is produced from non-enzymatic reactions with DHAP or G3P produced in glycolysis. Methylglyoxal is then converted into S-d-lactoylglutathione by enzyme GLO1 with a catalytic amount of GSH, of which is hydrolyzed into non-toxic D-lactate via GLO2, during which GSH is reformed to be consumed again by GLO1 with a new molecule of MG. D-lactate ultimately goes on to be metabolized into pyruvate. | 1 | Applied and Interdisciplinary Chemistry |
The perturbative treatment of the Stark effect has some problems. In the presence of an electric field, states of atoms and molecules that were previously bound (square-integrable), become formally (non-square-integrable) resonances of finite width. These resonances may decay in finite time via field ionization. For low lying states and not too strong fields the decay times are so long, however, that for all practical purposes the system can be regarded as bound. For highly excited states and/or very strong fields ionization may have to be accounted for. (See also the article on the Rydberg atom). | 0 | Theoretical and Fundamental Chemistry |
The Center for Orphan Drug Research at the University of Minnesota College of Pharmacy helps small companies with insufficient in-house expertise and resources in drug synthesis, formulation, pharmacometrics, and bio-analysis.
The Keck Graduate Institute Center for Rare Disease Therapies (CRDT) in Claremont, California, supports projects to revive potential orphan drugs whose development has stalled by identifying barriers to commercialization, such as problems with formulation and bio-processing.
Numerous advocacy groups such as the National Organization for Rare Disorders, Global Genes Project, Childrens Rare Disease Network, Abetalipoproteinemia Collaboration Foundation, Zellweger Baby Support Network, and the Friedreichs Ataxia Research Alliance have been founded in order to advocate on behalf of patients with rare diseases with a particular emphasis on diseases that affect children. | 1 | Applied and Interdisciplinary Chemistry |
The absorption of energy followed by the emission of light is often described by the term luminescence. The exact term used is based on the energy source responsible for the luminescence as in color-change phenomena.
*Electrical – electroluminescence Galvanoluminescence Sonoluminescence.
*Photons (light) – Photoluminescence Fluorescence Phosphorescence Biofluorescence.
*Chemical – Chemiluminescence Bioluminescence Electrochemiluminescence.
*Thermal – Thermoluminescence Pyroluminescence Candololuminescence.
*Electron Beam – Cathodoluminescence Anodoluminescence Radioluminescence.
*Mechanical – Triboluminescence Fractoluminescence Mechanoluminescence Crystalloluminescence Lyoluminescence Elasticoluminescence.
Many of these phenomena are widely used in consumer products and other important outlets. Cathodoluminescence is used in cathode ray tubes, photoluminescence in fluorescent lighting and plasma display panels, phosphorescence in safety signs and low energy lighting, fluorescence in pigments, inks, optical brighteners, safety clothing, and biological and medicinal analysis and diagnostics, chemoluminescence and bioluminescence in analysis, diagnostics and sensors, and electroluminescence in the burgeoning areas of light-emitting diodes (LEDs/OLEDs), displays and panel lighting. Important new developments are taking place in the areas of quantum dots and metallic nanoparticles. | 0 | Theoretical and Fundamental Chemistry |
Sucrose is a disaccharide formed from condensation of glucose and fructose to produce α-D-glucopyranosyl-(1→2)-β-D-fructofuranoside. Sucrose has 8 hydroxyl groups which can be reacted with fatty acid esters to produce sucrose esters. Among the 8 hydroxyl groups on sucrose, three (C6, C1, and C6) are primary while the others (C2, C3, C4, C3, and C4) are secondary. (The numbers 1-6 indicate the position of the carbons on glucose while the numbers 1-6 indicate the position of the carbons on fructose.) The three primary hydroxyl groups are more reactive due to lower steric hindrance, so they react with fatty acids first, resulting in a sucrose mono-, di-, or triester. Typical saturated fatty acids that are used to produce sucrose esters are lauric acid, myristic acid, palmitic acid, stearic acid and behenic acid, and typical unsaturated fatty acids are oleic acid and erucic acid. | 0 | Theoretical and Fundamental Chemistry |
Modern botanical gardens were preceded by medieval physic gardens, often monastic gardens, that existed by 800 at least. Gardens of this time included various sections including one for medicinal plants called the or . Pope Nicholas V set aside part of the Vatican grounds in 1447 for a garden of medicinal plants that were used to promote the teaching of botany, and this was a forerunner to the academic botanical gardens at Padua and Pisa established in the 1540s. Certainly the founding of many early botanic gardens was instigated by members of the medical profession.
The naturalist William Turner established physic gardens at Cologne, Wells, and Kew; he also wrote to Lord Burleigh recommending that a physic garden be established at Cambridge University with himself at its head. The 1597 Herball, or Generall Historie of Plantes by herbalist John Gerard was said to be the catalogue raisonné of physic gardens, both public and private, which were instituted throughout Europe. It listed 1,030 plants found in his physic garden at Holborn, and was the first such catalogue printed.
The garden in Oxford, founded by Henry Danvers, 1st Earl of Danby, with Jacob Bobart the Elder as Superintendent, dates to 1632. Begun in Westminster and later moved to Chelsea, the Apothecaries founded the Chelsea Physic Garden in 1673, of which Philip Miller, author of The Gardeners Dictionary, was the most notable Director. By 1676, the position of "Keeper of the Physic Garden" was held by the Professor of Botany at the University of Edinburgh.
Some of the earliest physic gardens included:
* 1334, Venice; and at Salerno, founded by Matthaeus Silvaticus
* 1544, Pisa, begun by Cosimo de' Medici, with Luca Ghini and Andrea Cesalpino for its first two directors
* 1545, Padua
* 1547, Bologna, founded by Ghini
* 1560, Zurich, founded by Conrad Gessner
* 1570, Paris
* 1577, Leyden, under direction of Carolus Clusius
* 1580, Leipzig
* 1593, Montpelier, by Henry IV | 1 | Applied and Interdisciplinary Chemistry |
Pyruvate is oxidized to acetyl-CoA and CO by the pyruvate dehydrogenase complex (PDC). The PDC contains multiple copies of three enzymes and is located in the mitochondria of eukaryotic cells and in the cytosol of prokaryotes. In the conversion of pyruvate to acetyl-CoA, one molecule of NADH and one molecule of CO is formed. | 1 | Applied and Interdisciplinary Chemistry |
As far back as 1974, DNA sequence similarity was recognized as a valuable tool for determining relationships among taxa. Structural genes in general are more highly conserved due to functional constraint, and so can prove useful in examinations of more disparate taxa. Original analyses enriched samples for structural genes via hybridization to mRNA.
More recent phylogenetic approaches focused on structural genes of known function, conserved to varying degrees. rRNA sequences frequent targets, as they are conserved in all species. Microbiology has specifically targeted the 16S gene to determine species level differences. In higher-order taxa, COI is now considered the “barcode of life,” and is applied for most biological identification. | 1 | Applied and Interdisciplinary Chemistry |
Ketones are produced on massive scales in industry as solvents, polymer precursors, and pharmaceuticals. In terms of scale, the most important ketones are acetone, methylethyl ketone, and cyclohexanone. They are also common in biochemistry, but less so than in organic chemistry in general. The combustion of hydrocarbons is an uncontrolled oxidation process that gives ketones as well as many other types of compounds. | 0 | Theoretical and Fundamental Chemistry |
A spring type accumulator is similar in operation to the gas-charged accumulator above, except that a heavy spring (or springs) is used to provide the compressive force. According to Hooke's law the magnitude of the force exerted by a spring is linearly proportional to its change of length. Therefore, as the spring compresses, the force it exerts on the fluid is increased linearly. | 1 | Applied and Interdisciplinary Chemistry |
There is a half-life describing any exponential-decay process. For example:
*As noted above, in radioactive decay the half-life is the length of time after which there is a 50% chance that an atom will have undergone nuclear decay. It varies depending on the atom type and isotope, and is usually determined experimentally. See List of nuclides.
*The current flowing through an RC circuit or RL circuit decays with a half-life of or , respectively. For this example the term half time tends to be used rather than "half-life", but they mean the same thing.
*In a chemical reaction, the half-life of a species is the time it takes for the concentration of that substance to fall to half of its initial value. In a first-order reaction the half-life of the reactant is , where (also denoted as ) is the reaction rate constant. | 0 | Theoretical and Fundamental Chemistry |
FYVE, RhoGEF and PH domain containing (FGD) is a gene family consisting of:
* FGD1
* FGD2
* FGD3
* FGD4
Type 1 is associated with Aarskog-Scott syndrome. | 1 | Applied and Interdisciplinary Chemistry |
Earth's mantle is a significant reservoir of carbon. The mantle contains more carbon than the crust, oceans, biosphere, and atmosphere put together. The figure is estimated to be very roughly 10 kg. Carbon concentration in the mantle is very variable, varying by more than a factor of 100 between different parts.
The form carbon takes depends on its oxidation state, which depends on the oxygen fugacity of the environment. Carbon dioxide and carbonate are found where the oxygen fugacity is high. Lower oxygen fugacity results in diamond formation, first in eclogite, then peridotite, and lastly in fluid water mixtures. At even lower oxygen fugacity, methane is stable in contact with water, and even lower, metallic iron and nickel form along with carbides. Iron carbides include FeC and FeC.
Minerals that contain carbon include calcite and its higher density polymorphs. Other significant carbon minerals include magnesium and iron carbonates. Dolomite is stable above 100 km depth. Below 100 km, dolomite reacts with orthopyroxine (found in peridotite) to yield magnesite (an iron magnesium carbonate). Below 200 km deep, carbon dioxide is reduced by ferrous iron (Fe), forming diamond, and ferric iron (Fe). Even deeper pressure induced disproportionation of iron minerals produces more ferric iron, and metallic iron. The metallic iron combines with carbon to form the mineral cohenite with formula FeC. Cohenite also contains some nickel substituting for iron. This form or carbon is called "carbide". Diamond forms in the mantle below 150 km deep, but because it is so durable, it can survive in eruptions to the surface in kimberlites, lamproites, or ultramafic lamprophyres.
Xenoliths can come from the mantle, and different compositions come from different depths. Above 90 km (3.2 GPa) spinel peridotite occurs, below this garnet peridotite is found.
Inclusions trapped in diamond can reveal the material and conditions much deeper in the mantle. Large gem diamonds are usually formed in the transition zone part of the mantle, (410 to 660 km deep) and crystallise from a molten iron-nickel-carbon solution, that also contains sulfur and trace amounts of hydrogen, chromium, phosphorus and oxygen. Carbon atoms constitute about 12% of the melt (about 3% by mass). Inclusions of the crystallised metallic melt are sometimes included in diamonds. Diamond can be caused to precipitate from the liquid metal, by increasing pressure, or by adding sulfur.
Fluid inclusions in crystals from the mantle have contents that most often are liquid carbon dioxide, but which also include carbon oxysulfide, methane and carbon monoxide
Material is added by subduction from the crust. This includes the major carbon containing sediments such as limestone, or coal. Each year 2×10 kg of CO is transferred from the crust to the mantle by subduction. (1700 tons of carbon per second).
Upwelling mantle material can add to the crust at mid oceanic ridges. Fluids can extract carbon from the mantle and erupt in volcanoes. At 330 km deep a liquid consisting of carbon dioxide and water can form. It is highly corrosive, and dissolves incompatible elements from the solid mantle. These elements include uranium, thorium, potassium, helium and argon. The fluids can then go on to cause metasomatism or extend to the surface in carbonatite eruptions. The total mid oceanic ridge, and hot spot volcanic emissions of carbon dioxide match the loss due to subduction: 2×10 kg of CO per year.
In slowly convecting mantle rocks, diamond that slowly rises above 150 km will slowly turn into graphite or be oxidised to carbon dioxide or carbonate minerals. | 0 | Theoretical and Fundamental Chemistry |
Under the assumptions of an incompressible fluid with negligible viscosity, Bernoulli's principle states that the hydraulic energy is constant
at any two points in the flowing liquid. Here is fluid speed, is the acceleration due to gravity, is the height above some reference point, is the pressure, and is the density.
In order to derive Torricellis formula the first point with no index is taken at the liquids surface, and the second just outside the opening. Since the liquid is assumed to be incompressible, is equal to and ; both can be represented by one symbol . The pressure and are typically both atmospheric pressure, so . Furthermore
is equal to the height of the liquid's surface over the opening:
The velocity of the surface can by related to the outflow velocity by the continuity equation , where is the orifices cross section and is the (cylindrical) vessels cross section. Renaming to (A like Aperture) gives:
Torricelli's law is obtained as a special case when the opening is very small relative to the horizontal cross-section of the container :
Torricelli's law can only be applied when viscous effects can be neglected which is the case for water flowing out through orifices in vessels. | 1 | Applied and Interdisciplinary Chemistry |
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