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Friedrich Wöhler discovered that an organic substance, urea, could be produced from inorganic starting materials in 1828. That was an important conceptual milestone in chemistry by being the first example of a synthesis of a substance that had been known only as a byproduct of living processes. Wöhler obtained urea by treating silver cyanate with ammonium chloride, a simple, one-step synthesis:
: AgNCO + NHCl → (NH)CO + AgCl
Camphor was a scarce and expensive natural product with a worldwide demand. Haller and Blanc synthesized it from camphor acid; however, the precursor, camphoric acid, had an unknown structure. When Finnish chemist Gustav Komppa synthesized camphoric acid from diethyl oxalate and 3,3-dimethylpentanoic acid in 1904, the structure of the precursors allowed contemporary chemists to infer the complicated ring structure of camphor. Shortly thereafter, William Perkin published another synthesis of camphor. The work on the total chemical synthesis of camphor allowed Komppa to begin industrial production of the compound, in Tainionkoski, Finland, in 1907.
The American chemist Robert Burns Woodward was a pre-eminent figure in developing total syntheses of complex organic molecules, some of his targets being cholesterol, cortisone, strychnine, lysergic acid, reserpine, chlorophyll, colchicine, vitamin B, and prostaglandin F-2a.
Vincent du Vigneaud was awarded the 1955 Nobel Prize in Chemistry for the total synthesis of the natural polypeptide oxytocin and vasopressin, which reported in 1954 with the citation "for his work on biochemically important sulphur compounds, especially for the first synthesis of a polypeptide hormone."
Another gifted chemist is Elias James Corey, who won the Nobel Prize in Chemistry in 1990 for lifetime achievement in total synthesis and for the development of retrosynthetic analysis. | 0 | Organic Chemistry |
Trimethyl orthoformate and triethylorthoacetate are reagents. Another example is the bicyclic OBO protecting group (4-methyl-2,6,7-trioxa-bicyclo[2.2.2]octan-1-yl) which is formed by the action of (3-methyloxetan-3-yl)methanol on activated carboxylic acids in the presence of Lewis acids. The group is base stable and can be cleaved in two steps under mild conditions, mildly acidic hydrolysis yields the ester of tris(hydroxymethyl)ethane which is then cleaved using e.g. an aqueous carbonate solution. | 0 | Organic Chemistry |
Lead(II) fluoride is the inorganic compound with the formula PbF. It is a white solid. The compound is polymorphic, at ambient temperatures it exists in orthorhombic (PbCl type) form, while at high temperatures it is cubic (Fluorite type). | 0 | Organic Chemistry |
The first step in understanding the chemistry of freshwater is to establish the relevant concentrations of the parameters of interest. Conventionally this is done by taking representative samples of the water for subsequent analysis in a laboratory. However, in-situ monitoring using hand-held analytical equipment or using bank-side monitoring stations are also used. | 2 | Environmental Chemistry |
Vis viva (from the Latin for "living force") is a historical term used to describe a quantity similar to kinetic energy in an early formulation of the principle of conservation of energy. | 7 | Physical Chemistry |
Human intestinal microbiota contribute to the etiology of colorectal cancer via their metabolome. In particular, the conversion of primary bile acids to secondary bile acids as a consequence of bacterial metabolism in the colon promotes carcinogenesis. | 1 | Biochemistry |
Recent research suggests that cAMP affects the function of higher-order thinking in the prefrontal cortex through its regulation of ion channels called hyperpolarization-activated cyclic nucleotide-gated channels (HCN). When cAMP stimulates the HCN, the channels open, This research, especially the cognitive deficits in age-related illnesses and ADHD, is of interest to researchers studying the brain.
cAMP is involved in activation of trigeminocervical system leading to neurogenic inflammation and causing migraine. | 1 | Biochemistry |
Ocean alkalinity enhancement (OAE) is a proposed "carbon dioxide removal (CDR) method that involves deposition of alkaline minerals or their dissociation products at the ocean surface". The process would increase surface total alkalinity. It would work to increase ocean absorption of . The process involves increasing the amount of bicarbonate (HCO-) through accelerated weathering (enhanced weathering) of rocks (silicate, limestone and quicklime). This process mimics the silicate-carbonate cycle. The either becomes bicarbonate, remaining in that form for more than 100 years, or may precipitate into calcium carbonate (CaCO). When calcium carbonate is buried in the deep ocean, it can hold the carbon indefinitely when utilizing silicate rocks.
Enhanced weathering is one type of ocean alkalinity enhancement. Enhanced weathering increases alkalinity by scattering fine rock particles. This can happen on land and in the ocean (even though the outcome eventually affects the ocean).
In addition to sequestering , alkalinity addition buffers the pH of the ocean therefore reducing ocean acidification. However, little is known about how organisms respond to added alkalinity, even from natural sources. For example, weathering of some silicate rocks could release a large amount of trace metals at the weathering site.
Cost and energy consumed by ocean alkalinity enhancement (mining, pulverizing, transport) is high compared to other CDR techniques. The cost is estimated to be 20–50 USD per ton of CO (for "direct addition of alkaline minerals to the ocean").
Carbon sequestered as bicarbonate in the ocean amounts to about 30% of carbon emissions since the Industrial Revolution.
Experimental materials include limestone, brucite, olivine and alkaline solutions. Another approach is to use electricity to raise alkalinity during desalination to capture waterborne CO2. | 9 | Geochemistry |
In geometry and crystallography, a Bravais lattice, named after , is an infinite array of discrete points generated by a set of discrete translation operations described in three dimensional space by
where the n are any integers, and a are primitive translation vectors, or primitive vectors, which lie in different directions (not necessarily mutually perpendicular) and span the lattice. The choice of primitive vectors for a given Bravais lattice is not unique. A fundamental aspect of any Bravais lattice is that, for any choice of direction, the lattice appears exactly the same from each of the discrete lattice points when looking in that chosen direction.
The Bravais lattice concept is used to formally define a crystalline arrangement and its (finite) frontiers. A crystal is made up of one or more atoms, called the basis or motif, at each lattice point. The basis may consist of atoms, molecules, or polymer strings of solid matter, and the lattice provides the locations of the basis.
Two Bravais lattices are often considered equivalent if they have isomorphic symmetry groups. In this sense, there are 5 possible Bravais lattices in 2-dimensional space and 14 possible Bravais lattices in 3-dimensional space. The 14 possible symmetry groups of Bravais lattices are 14 of the 230 space groups. In the context of the space group classification, the Bravais lattices are also called Bravais classes, Bravais arithmetic classes, or Bravais flocks. | 3 | Analytical Chemistry |
Two examples of natural phosphoramidates are phosphocreatine and the phosphoramidate formed when histidine residues in histidine kinases are phosphorylated.
An example of a phosphorodiamidate is morpholino which is used in molecular biology. | 0 | Organic Chemistry |
Besides having adequate dentinal moisture, agitation of the primers during application of two-step etch-and-rinse adhesives may be critical for optimal penetration into the demineralized collagen fibres. It also may aid the evaporation of residual water in the adhesive and hybrid layers, thus preventing nano leakage.
In a clinical trial comparing the performance of Prime & Bond NT using no rubbing action, slight rubbing action and vigorous rubbing action in the restoration of NCCLs, 92.5% of restorations in vigorous rubbing action group were found to retain after 24 months of clinical service. For the other two groups, the retention rates of the restoration were slightly lower, at 82.5%. | 7 | Physical Chemistry |
Kagome () is a traditional Japanese woven bamboo pattern; its name is composed from the words kago, meaning "basket", and me, meaning "eye(s)", referring to the pattern of holes in a woven basket.
The kagome pattern is common in bamboo weaving in East Asia. In 2022, archaeologists found bamboo weaving remains at the Dongsunba ruins in Chongqing, China, 200 BC. After 2200 years, the kagome pattern is still clear.
It is a woven arrangement of laths composed of interlaced triangles such that each point where two laths cross has four neighboring points, forming the pattern of a trihexagonal tiling. The woven process gives the Kagome a chiral wallpaper group symmetry, p6 (632). | 3 | Analytical Chemistry |
In the context of coding theory, can be constructed by measuring the expected number of extra bits required to code samples from using a code optimized for rather than the code optimized for . | 7 | Physical Chemistry |
A portable, advanced sensor based on infrared spectroscopy in a hollow fiber matched to a silicon-micromachined fast gas chromatography column can analyze illegal stimulants and precursors with nanogram-level sensitivity.
Raman spectroscopy has been successfully tested to detect explosives and their precursors.
Technologies able to detect precursors in the environment could contribute to an early location of sites where illegal substances (both explosives and drugs of abuse) are produced. | 1 | Biochemistry |
There are several aspects of FAIRE-seq that require attention when analysing and interpreting the data. For one, it has been stated that FAIRE-seq will have a higher coverage at enhancer regions over promoter regions. This is in contrast to the alternative method of DNase-seq who is known to show a higher sensitivity towards promoter regions. In addition, FAIRE-seq has been stated to show prefers for internal introns and exons. In general it is also believed that FAIRE-seq data displays a higher background level, making it a less sensitive method. | 1 | Biochemistry |
Beridze was awarded the Order of Honour of Georgia in 1999. He was awarded the Serge Durmishidze prize in Biochemistry in 2009. | 1 | Biochemistry |
The ORNL conducted FACE experiments where levels were increased above ambient levels in forest stands. These experiments showed:
* Increased root production stimulated by increased , resulting in more soil carbon.
* An initial increase of net primary productivity, which was not sustained.
* Faster decline in nitrogen availability in increased forest plots.
* Change in plant community structure, with minimal change in microbial community structure.
* Enhanced cannot significantly increase the leaf carrying capacity or leaf area index of an area.
FACE experiments have been criticized as not being representative of the entire globe. These experiments were not meant to be extrapolated globally. Similar experiments are being conducted in other regions such as in the Amazon rainforest in Brazil. | 2 | Environmental Chemistry |
Fluxing salt, like chlorides are also liquid inclusions. They come from flux treatments added to the melt for cleaning. | 8 | Metallurgy |
Peters four-step chemistry is a systematically reduced mechanism for methane combustion, named after Norbert Peters, who derived it in 1985. The mechanism reads as
The mechanism predicted four different regimes where each reaction takes place. The third reaction, known as radical consumption layer, where most of the heat is released, and the first reaction, also known as fuel consumption layer, occur in a narrow region at the flame. The fourth reaction is the hydrogen oxidation layer, whose thickness is much larger than the former two layers. Finally, the carbon monoxide oxidation layer is the largest of them all, corresponding to the second reaction, and oxidizes very slowly. | 7 | Physical Chemistry |
A study was conducted to define the pharmacological response of humans to ractopamine. A single oral dose of 40 mg of ractopamine hydrochloride was given to human volunteers. The drug was rapidly absorbed; the mean blood plasma half-life was around 4 hrs and it was not detected in plasma 24 hrs after dosing. Less than 5% of total ractopamine excreted represented the parent drug, while the urinary metabolites were monoglucuronide and monosulfate conjugates, with ractopamine monosulfate being the major metabolite present.
The metabolic fate of ractopamine hydrochloride is similar in the target species (pigs and cattle), laboratory animals, and humans. Besides the pharmacology effect, ractopamine may cause intoxication effect; therefore, any consumption by humans of a meat and/or byproducts of animals that consumed ractopamine with feed for growth stimulation, may result in such clinical effects as tachycardia and other heart rate increases, tremor, headache, muscle spasm, or high arterial blood pressure. The effect of ractopamine on humans is not entirely known, but consumption of products that contain ractopamine residues is not advisable for persons with cardiovascular diseases. | 4 | Stereochemistry |
Targeted gene knockout using CRISPR/Cas9 requires the use of a delivery system to introduce the sgRNA and Cas9 into the cell. Although a number of different delivery systems are potentially available for CRISPR, genome-wide loss-of-function screens are predominantly carried out using third generation lentiviral vectors. These lentiviral vectors are able to efficiently transduce a broad range of cell types and stably integrate into the genome of dividing and non-dividing cells.
Third generation lentiviral particles are produced by co-transfecting 293T human embryonic kidney (HEK) cells with:
# two packaging plasmids, one encoding Rev and the other Gag and Pol;
# an interchangeable envelope plasmid that encodes for an envelope glycoprotein of another virus (most commonly the G protein of vesicular stomatitis virus (VSV-G));
# one or two (depending on the applied library) transfer plasmids, encoding for Cas9 and sgRNA, as well as selection markers.
The lentiviral particle-containing supernatant is harvested, concentrated and subsequently used to infect the target cells. The exact protocol for lentiviral production will vary depending on the research aim and applied library. If a two vector-system is used, for example, cells are sequentially transduced with Cas9 and sgRNA in a two-step procedure. Although more complex, this has the advantage of a higher titre for the sgRNA library virus. | 1 | Biochemistry |
Middle-of-house testing is a new development, started by The Loop in the UK. Testing happens on-site, but without face-to-face interaction with the public. Samples from medical incidents are tested and alerts can be issued after multiple incidents with a trend are identified. | 3 | Analytical Chemistry |
An enzyme modulator is a type of drug which modulates enzymes. They include enzyme inhibitors and enzyme inducers. In an homogeneous assay, "an enzyme modulator ... is covalently linked to the ligand which competes with free ligand from the test sample for the available antibodies." | 1 | Biochemistry |
HPLC detectors fall into two main categories: universal or selective. Universal detectors typically measure a bulk property (e.g., refractive index) by measuring a difference of a physical property between the mobile phase and mobile phase with solute while selective detectors measure a solute property (e.g., UV-Vis absorbance) by simply responding to the physical or chemical property of the solute. HPLC most commonly uses a UV-Vis absorbance detector; however, a wide range of other chromatography detectors can be used. A universal detector that complements UV-Vis absorbance detection is the charged aerosol detector (CAD). A kind of commonly utilized detector includes refractive index detectors, which provide readings by measuring the changes in the refractive index of the eluant as it moves through the flow cell. In certain cases, it is possible to use multiple detectors, for example LCMS normally combines UV-Vis with a mass spectrometer.
When used with an electrochemical detector (ECD) the HPLC-ECD selectively detects neurotransmitters such as: norepinephrine, dopamine, serotonin, glutamate, GABA, acetylcholine and others in neurochemical analysis research applications. The HPLC-ECD detects neurotransmitters to the femtomolar range. Other methods to detect neurotransmitters include liquid chromatography-mass spectrometry, ELISA, or radioimmunoassays. | 3 | Analytical Chemistry |
Devapamil is a calcium channel blocker. It is also known as desmethoxyverapamil, which is a phenylalkylamine (PAA) derivative. Devapamil not only inhibits by blocking the calcium gated channels, but also by depolarizing the membrane during the sodium-potassium exchanges. | 1 | Biochemistry |
*McGannon, Harold E. editor (1971). The Making, Shaping and Treating of Steel: Ninth Edition. Pittsburgh, Pennsylvania: United States Steel Corporation.
*Smil, Vaclav (2006). [https://books.google.com/books?id=tl23A0mCPLUC Transforming the twentieth century: technical innovations and their consequences, Volume 2]. Oxford University Press US. .
*Brock, James W.; Elzinga, Kenneth G. (1991). [https://books.google.com/books?id=2Xj1qt1daHAC Antitrust, the market, and the state: the contributions of Walter Adams]. M. E. Sharpe. .
*Tweraser, Kurt (2000). The Marshall Plan and the Reconstruction of the Austrian Steel Industry 1945–1953. in: Bischof, Gunther et al. (2000). [https://books.google.com/books?id=pKlWyYA26GMC The Marshall Plan in Austria]. Transaction Publishers. . pp. 290–322. | 8 | Metallurgy |
The Crick, Brenner, Barnett and Watts-Tobin experiment first demonstrated that codons consist of three DNA bases.
Marshall Nirenberg and J. Heinrich Matthaei were the first to reveal the nature of a codon in 1961. They used a cell-free system to translate a poly-uracil RNA sequence (i.e., UUUUU...) and discovered that the polypeptide that they had synthesized consisted of only the amino acid phenylalanine. They thereby deduced that the codon UUU specified the amino acid phenylalanine.
This was followed by experiments in Severo Ochoa's laboratory that demonstrated that the poly-adenine RNA sequence (AAAAA...) coded for the polypeptide poly-lysine and that the poly-cytosine RNA sequence (CCCCC...) coded for the polypeptide poly-proline. Therefore, the codon AAA specified the amino acid lysine, and the codon CCC specified the amino acid proline. Using various copolymers most of the remaining codons were then determined.
Subsequent work by Har Gobind Khorana identified the rest of the genetic code. Shortly thereafter, Robert W. Holley determined the structure of transfer RNA (tRNA), the adapter molecule that facilitates the process of translating RNA into protein. This work was based upon Ochoa's earlier studies, yielding the latter the Nobel Prize in Physiology or Medicine in 1959 for work on the enzymology of RNA synthesis.
Extending this work, Nirenberg and Philip Leder revealed the code's triplet nature and deciphered its codons. In these experiments, various combinations of mRNA were passed through a filter that contained ribosomes, the components of cells that translate RNA into protein. Unique triplets promoted the binding of specific tRNAs to the ribosome. Leder and Nirenberg were able to determine the sequences of 54 out of 64 codons in their experiments. Khorana, Holley and Nirenberg received the 1968 Nobel for their work.
The three stop codons were named by discoverers Richard Epstein and Charles Steinberg. "Amber" was named after their friend Harris Bernstein, whose last name means "amber" in German. The other two stop codons were named "ochre" and "opal" in order to keep the "color names" theme. | 1 | Biochemistry |
Iron is also potentially toxic. Its ability to donate and accept electrons means that it can catalyze the conversion of hydrogen peroxide into free radicals. Free radicals can cause damage to a wide variety of cellular structures, and ultimately kill the cell.
Iron bound to proteins or cofactors such as heme is safe. Also, there are virtually no truly free iron ions in the cell, since they readily form complexes with organic molecules. However, some of the intracellular iron is bound to low-affinity complexes, and is termed labile iron or "free" iron. Iron in such complexes can cause damage as described above.
To prevent that kind of damage, all life forms that use iron bind the iron atoms to proteins. This binding allows cells to benefit from iron while also limiting its ability to do harm. Typical intracellular labile iron concentrations in bacteria are 10-20 micromolar, though they can be 10-fold higher in anaerobic environment, where free radicals and reactive oxygen species are scarcer. In mammalian cells, intracellular labile iron concentrations are typically smaller than 1 micromolar, less than 5 percent of total cellular iron. | 1 | Biochemistry |
The tool has a crucial part to creation of the final product. The tool consists of two main functions:
# Localized heating
# Material flow
The tool at its most simplest form consist of a shoulder, a small cylinder with a diameter of 50 mm, and a pin, a small threaded cylinder similar to a drill. The tool itself has been modified to reduce displaced volume of the metals as they merged. Recently two new pin geometries have arisen:
# Flared-Triflute – introducing flutes (large carving vertically on the pin)
#A-skew – the pin axis being inclined to the axis of the spindle. | 8 | Metallurgy |
A superconductor can be Type I, meaning it has a single critical field, above which all superconductivity is lost and below which the magnetic field is completely expelled from the superconductor; or Type II, meaning it has two critical fields, between which it allows partial penetration of the magnetic field through isolated points. These points are called vortices. Furthermore, in multicomponent superconductors it is possible to have a combination of the two behaviours. In that case the superconductor is of Type-1.5. | 7 | Physical Chemistry |
Exposure to pyridine would normally lead to its inhalation and absorption in the lungs and gastrointestinal tract, where it either remains unchanged or is metabolized. The major products of pyridine metabolism are N-methylpyridiniumhydroxide, which are formed by N-methyltransferases (e.g., pyridine N-methyltransferase), as well as pyridine N-oxide, and 2-, 3-, and 4-hydroxypyridine, which are generated by the action of monooxygenase. In humans, pyridine is metabolized only into N-methylpyridiniumhydroxide. | 0 | Organic Chemistry |
Caspases cleave keratin 18 at two sites during apoptosis. Cleavage at Asp396 generates a neo-epitope recognized by the monoclonal antibody M30®. This antibody does not recognize uncleaved K18 and is therefore specific for apoptotic epithelial cells. M30 Apoptosense® ELISA utilizes a second monoclonal antibody (M5) which recognizes an epitope N-terminal from the M30® epitope.
M30 Apoptosense® ELISA can be combined with the M65® ELISA (uncleaved K18) (PEVIVA®, VLVbio) to determine cell death mode (apoptosis versus necrosis). | 1 | Biochemistry |
Gene therapy utilizes the delivery of DNA into cells, which can be accomplished by several methods, summarized below. The two major classes of methods are those that use recombinant viruses (sometimes called biological nanoparticles or viral vectors) and those that use naked DNA or DNA complexes (non-viral methods). | 1 | Biochemistry |
Preparation of McIlvaine buffer requires disodium phosphate and citric acid. One liter of 0.2M stock solution of disodium hydroxyphosphate can be prepared by dissolving 28.38g of disodium phosphate in water, and adding a quantity of water sufficient to make one liter. One liter of 0.1M stock solution of citric acid can be prepared by dissolving 19.21g of citric acid in water, and adding a quantity of water sufficient to make one liter. From these stock solutions, McIlvaine buffer can be prepared in accordance with the following table: | 1 | Biochemistry |
A cloning vector need not contain suitable elements for the expression of a cloned target gene, such as a promoter and ribosomal binding site (RBS), many however do, and may then work as an expression vector. The target DNA may be inserted into a site that is under the control of a particular promoter necessary for the expression of the target gene in the chosen host. Where the promoter is present, the expression of the gene is preferably tightly controlled and inducible so that proteins are only produced when required. Some commonly used promoters are the T7 and lac promoters. The presence of a promoter is necessary when screening techniques such as blue-white selection are used.
Cloning vectors without promoter and RBS for the cloned DNA sequence are sometimes used, for example when cloning genes whose products are toxic to E. coli cells. Promoter and RBS for the cloned DNA sequence are also unnecessary when first making a genomic or cDNA library of clones since the cloned genes are normally subcloned into a more appropriate expression vector if their expression is required.
Some vectors are designed for transcription only with no heterologous protein expressed, for example for in vitro mRNA production. These vectors are called transcription vectors. They may lack the sequences necessary for polyadenylation and termination, therefore may not be used for protein production. | 1 | Biochemistry |
Levonorgestrel acetate (LNG-A), or levonorgestrel 17β-acetate, also known as 3-ketonorgestimate, is a progestin which was never marketed. It is a progestogen ester and is the C17β acetate ester and a prodrug of levonorgestrel. Norgestimate is the C3 oxime of LNG-A. The drug is a minor active metabolite of norgestimate, which is a prodrug of norelgestromin and to a lesser extent of levonorgestrel and LNG-A. LNG-A has high affinity for the progesterone receptor, about 135% of that of promegestone (relative to 150% for levonorgestrel). Along with levonorgestrel butanoate, LNG-A was investigated as a hormonal contraceptive by the Population Council. | 4 | Stereochemistry |
Along adiabatic and isentropic processes, such as those theoretically associated with pumping processes in transcritical cycles, the enthalpy difference across both a compression and an expansion is computed as:
Consequently, a working fluid with a lower specific volume (hence higher density) can inevitably be compressed spending a lower mechanical work than one with low density (more gas like).
In transcritical cycles, the very high maximum pressures and the liquid conditions along the whole compression phase ensure a higher density and a lower specific volume with respect to supercritical counterparts. Considering the different physical phases though which compression processes occur, transcritical and supercritical cycles employ pumps (for liquids) and compressors (for gases), respectively, during the compression step. | 7 | Physical Chemistry |
Extraction in chemistry is a separation process consisting of the separation of a substance from a matrix. The distribution of a solute between two phases is an equilibrium condition described by partition theory. This is based on exactly how the analyte moves from the initial solvent into the extracting solvent. The term washing may also be used to refer to an extraction in which impurities are extracted from the solvent containing the desired compound. | 3 | Analytical Chemistry |
* The recA1 mutation is a single point mutation that replaces glycine 160 of the recA polypeptide with an aspartic acid residue in order to disable the activity of the recombinases and inactivate homologous recombination.
* The endA1 mutation inactivates an intracellular endonuclease to prevent it from degrading the inserted plasmid. | 1 | Biochemistry |
Muon spin spectroscopy, also known as µSR, is an experimental technique based on the implantation of spin-polarized muons in matter and on the detection of the influence of the atomic, molecular or crystalline surroundings on their spin motion. The motion of the muon spin is due to the magnetic field experienced by the particle and may provide information on its local environment in a very similar way to other magnetic resonance techniques, such as electron spin resonance (ESR or EPR) and, more closely, nuclear magnetic resonance (NMR). | 7 | Physical Chemistry |
Gustavo R. Paz-Pujalt (born 1954) is a Peruvian American scientist and inventor. He holds 45 US patents and 59 international patents mainly in the areas of remote sensing, thin films, sensors, and upconversion materials. | 7 | Physical Chemistry |
Aerobic fermentation is essential for multiple industries, resulting in human domestication of several yeast strains. Beer and other alcoholic beverages, throughout human history, have played a significant role in society through drinking rituals, providing nutrition, medicine, and uncontaminated water. During the domestication process, organisms shift from natural environments that are more variable and complex to simple and stable environments with a constant substrate. This often favors specialization adaptations in domesticated microbes, associated with relaxed selection for non-useful genes in alternative metabolic strategies or pathogenicity. Domestication might be partially responsible for the traits that promote aerobic fermentation in industrial species. Introgression and HGT is common in Saccharomyces domesticated strains. Many commercial wine strains have significant portions of their DNA derived from HGT of non-Saccharomyces species. HGT and introgression are less common in nature than is seen during domestication pressures. For example, the important industrial yeast strain Saccharomyces pastorianus is an interspecies hybrid of S. cerevisiae and the cold tolerant S. eubayanus. This hybrid is commonly used in lager-brewing, which requires slow, low temperature fermentation. | 1 | Biochemistry |
Various techniques are available for strengthening concrete structures, to increase the load-carrying capacity or else to improve the in-service performance. These include increasing the concrete cross-section and adding material such as steel plate or fiber composites to enhance the tensile capacity or increase the confinement of the concrete for improved compression capacity. | 8 | Metallurgy |
The involvement of toll signalling in immunity was first demonstrated in the fruit fly, Drosophila melanogaster. Fruit flies have only innate immune responses allowing studies to avoid interference of adaptive immune mechanisms on signal transduction. The fly response to fungal or bacterial infection occurs through two distinct signalling cascades, one of which is the toll pathway and the other is the immune deficiency pathway. The toll pathway is similar to mammalian TLR signalling, but unlike mammalian TLRs, toll is not activated directly by pathogen-associated molecular patterns (PAMPs). Its receptor ectodomain recognizes the cleaved form of the cytokine spätzle, which is secreted in the haemolymph as an inactive dimeric precursor. The toll receptor shares the cytoplasmatic TIR domain with mammalian TLRs, but the ectodomain and intracytoplasmatic tail are different. This difference might reflect a function of these receptors as cytokine receptors rather than PRRs.
The toll pathway is activated by different stimuli, such as Gram positive bacteria, fungi and virulence factors. First, the Spätzle processing enzyme (SPE) is activated in response to infection and cleaves spätzle (spz). Cleaved spätzle then binds to the toll receptor and crosslinks its ectodomains. This triggers conformational changes in the receptor resulting in signalling through toll. From this point forward, the signalling cascade is very similar to mammalian signalling through TLRs. The toll-induced signalling complex (TICS) is composed of MyD88, Tube, and Pelle (the orthologue of mammalian IRAK). Signal from TICS is then transduced to Cactus (homologue of mammalian IκB), phosphorylated Cactus is polyubiquitylated and degraded, allowing nuclear translocation of DIF (dorsal-related immunity factor; a homologue of mammalian NF-κB) and induction of transcription of genes for antimicrobial peptides (AMPs) such as drosomycin.
Drosophila have a total of 9 toll family and 6 spz family genes that interact with each other to differing degrees. | 1 | Biochemistry |
LaNi has a calcium pentacopper (CaCu) type crystal structure, with a hexagonal lattice, space group is P6/mmm (No. 191), with lanthanum atom is located at coordinate origin 1a (0,0,0), two nickel atoms are located at 2c (1/ 3,2/3,0) and (2/3,1/3,0), the other three at 3g (1/2,0,1/2), (0,1/2,1/2), (1/2,1/2,1/2), with a=511pm, c=397pm. The unit cell contains 1 LaNi atom, the volume is 90×10 cm, the LaNi unit cell contains a larger The six deformed tetrahedral voids can be used to fill in hydrogen atoms. | 8 | Metallurgy |
Numerous ion channels undergo palmitoylation, a lipid modification process. Moreover, a significant subset of ion channels demonstrate a direct affinity for cholesterol binding. The regulation of ion channels by cholesterol can stem from both direct binding interactions and an indirect influence, facilitated by the localization of palmitoylated residues within lipid rafts. It's important to note that these two mechanisms are not mutually exclusive; they can concurrently contribute to the modulation of ion channel activity and localization.
The spatial arrangement of an ion channel can profoundly impact its activation potential. Proposed mechanisms for this phenomenon encompass alterations in membrane thickness and the concentration of lipid molecules critical for signaling. One instance of this is observed in TREK-1 channels, which transition between lipid rafts and PIP2 domains, where they interact with an activating lipid. Similarly, Kir2.1 channels experience inhibition due to cholesterol while being activated by PIP2. Consequently, a transition from cholesterol-enriched GM1 to PIP2-rich domains is anticipated to trigger channel activation. Conversely, the scenario is opposite for nAChR, which responds positively to cholesterol, eliciting its activation. | 1 | Biochemistry |
Alessandro Volta, a contemporary physicist, believed that the effect was explicable not by any vital force but rather it was the presence of two different metals that was generating the electricity. Volta demonstrated his theory by creating the first chemical electric battery. Despite their differences in opinion, Volta named the phenomenon of the chemical generation of electricity "Galvanism" after Galvani. | 7 | Physical Chemistry |
Researchers work in the Chesapeake Bay to collect information about water quality, plant and animal abundances, shoreline erosion, tides, waves, and harmful algal blooms. For example, the Virginia Institute of Marine Science monitors the abundance of submerged aquatic vegetation in the shallow areas of the Chesapeake Bay each summer. Many organizations run continuous monitoring programs. Monitoring programs set out instruments at fixed stations on buoys, moorings, and docks throughout the Bay to record things like temperature, salinity, chlorophyll-a concentration, dissolved oxygen, and turbidity over time.
Organizations actively collecting data in the Chesapeake Bay include, but are not limited to:
*Chesapeake Bay National Estuarine Research Reserve in Maryland
*Chesapeake Bay National Estuarine Research Reserve in Virginia
*Chesapeake Bay Program
*Hampton Roads Sanitation District
*Maryland Department of Natural Resources
*NASA GSFC Ocean Biology group
*NASA GSFC Applied Sciences group (Water Resources and Human Health areas)
*NOAA Chesapeake Bay Office
*Old Dominion University’s Earth and Ocean Sciences Department
*Smithsonian Environmental Research Center
*United States Geological Survey
*University of Maryland Center for Environmental Science
*Virginia Department of Environmental Quality
*Virginia Department of Health
*Virginia Institute of Marine Science
*Virginia Marine Resources Commission | 2 | Environmental Chemistry |
There are also other types of interactions that generalize the idea of interacting p orbitals in a conjugated system. The concept of hyperconjugation holds that certain σ bonds can also delocalize into a low-lying unoccupied orbital of a π system or an unoccupied p orbital. Hyperconjugation is commonly invoked to explain the stability of alkyl substituted radicals and carbocations. Hyperconjugation is less important for species in which all atoms satisfy the octet rule, but a recent computational study supports hyperconjugation as the origin of the increased stability of alkenes with a higher degree of substitution (Zaitsev's rule).
Homoconjugation is an overlap of two π-systems separated by a non-conjugating group, such as CH. Unambiguous examples are comparatively rare in neutral systems, due to a comparatively minor energetic benefit that is easily overridden by a variety of other factors; however, they are common in cationic systems in which a large energetic benefit can be derived from delocalization of positive charge (see the article on homoaromaticity for details.). Neutral systems generally require constrained geometries favoring interaction to produce significant degrees of homoconjugation. In the example below, the carbonyl stretching frequencies of the IR spectra of the respective compounds demonstrate homoconjugation, or lack thereof, in the neutral ground state molecules.
Due to the partial π character of formally σ bonds in a cyclopropane ring, evidence for transmission of "conjugation" through cyclopropanes has also been obtained.
Two appropriately aligned π systems whose ends meet at right angles can engage in spiroconjugation.
Vinylogy is the extension of a functional group through a conjugated organic bonding system, which transmits electronic effects. | 7 | Physical Chemistry |
Members of the chemokine family are divided into four groups depending on the spacing of their first two cysteine residues. Thus the nomenclature for chemokines is, e.g.: CCL1 for the ligand 1 of the CC-family of chemokines, and CCR1 for its respective receptor. | 1 | Biochemistry |
Chlorinated paraffins are synthesized by reaction of chlorine gas with unbranched paraffin fractions (<2 % isoparaffins, <100 ppm aromatics) at a temperature of 80–100 °C. The radical substitution may be promoted by UV-light.
: CH + y Cl → CHCl + y HCl
When the desired degree of chlorination is achieved, residues of hydrochloric acid and chlorine are blown off with nitrogen. Epoxidized vegetable oil, glycidyl ether or organophosphorous compounds may be added to the final product for improved stability at high temperatures.
Commercial products have been classified as substances of unknown or variable composition. CPs are complex mixtures of chlorinated n-alkanes containing thousands of homologues and isomers which are not completely separated by standard analytical methods.
CPs are produced in Europe, North America, Australia, Brazil, South Africa and Asia. In China, where most of the world production capacity is located, 600,000 tons of chlorinated paraffins were produced in 2007. Production and use volumes of CPs exceeded 1,000,000 tons in 2013. | 2 | Environmental Chemistry |
Trail pheromones are semiochemicals secreted from the body of an individual to affect the behavior of another individual receiving it. Trail pheromones often serve as a multi purpose chemical secretion that leads members of its own species towards a food source, while representing a territorial mark in the form of an allomone to organisms outside of their species. Specifically, trail pheromones are often incorporated with secretions of more than one exocrine gland to produce a higher degree of specificity. Considered one of the primary chemical signaling methods in which many social insects depend on, trail pheromone deposition can be considered one of the main facets to explain the success of social insect communication today. Many species of ants, including those in the genus Crematogaster use trail pheromones. | 1 | Biochemistry |
The chloroplastida chloroplasts, or green chloroplasts, are another large, highly diverse primary chloroplast lineage. Their host organisms are commonly known as green algae and land plants. They differ from glaucophyte and red algal chloroplasts in that they have lost their phycobilisomes, and contain chlorophyll b instead. Most green chloroplasts are (obviously) green, though some arent, like some forms of Hæmatococcus pluvialis, due to accessory pigments that override the chlorophylls green colors. Chloroplastida chloroplasts have lost the peptidoglycan wall between their double membrane, leaving an intermembrane space. Some plants seem to have kept the genes for the synthesis of the peptidoglycan layer, though they've been repurposed for use in chloroplast division instead.
Most of the chloroplasts depicted in this article are green chloroplasts.
Green algae and plants keep their starch inside their chloroplasts, and in plants and some algae, the chloroplast thylakoids are arranged in grana stacks. Some green algal chloroplasts contain a structure called a pyrenoid, which is functionally similar to the glaucophyte carboxysome in that it is where RuBisCO and CO are concentrated in the chloroplast.
Helicosporidium is a genus of nonphotosynthetic parasitic green algae that is thought to contain a vestigial chloroplast. Genes from a chloroplast and nuclear genes indicating the presence of a chloroplast have been found in Helicosporidium even if nobody's seen the chloroplast itself. | 5 | Photochemistry |
There have been reported cases of blood alcohol content higher than 1%:
* In 1982, a 24-year-old woman was admitted to the UCLA emergency room with a serum alcohol content of 1.51%, corresponding to a blood alcohol content of 1.33%. She was alert and oriented to person and place and survived. Serum alcohol concentration is not equal to nor calculated in the same way as blood alcohol content.
* In 1984, a 30-year-old man survived a blood alcohol concentration of 1.5% after vigorous medical intervention that included dialysis and intravenous therapy with fructose.
* In 1995, a man from Wrocław, Poland, caused a car accident near his hometown. He had a blood alcohol content of 1.48%; he was tested five times, with each test returning the same reading. He died a few days later of injuries from the accident.
* In 2004, an unidentified Taiwanese woman died of alcohol intoxication after immersion for twelve hours in a bathtub filled with 40% ethanol. Her blood alcohol content was 1.35%. It was believed that she had immersed herself as a response to the SARS epidemic.
* In South Africa, a man driving a Mercedes-Benz Vito light van containing 15 sheep allegedly stolen from nearby farms was arrested on December 22, 2010, near Queenstown in Eastern Cape. His blood had an alcohol content of 1.6%. Also in the vehicle were five boys and a woman, who were also arrested.
* On 26 October 2012, a man from Gmina Olszewo-Borki, Poland, who died in a car accident, recorded a blood alcohol content of 2.23%; however, the blood sample was collected from a wound and thus possibly contaminated.
* On 26 July 2013 a 30-year-old man from Alfredówka, Poland, was found by Municipal Police Patrol from Nowa Dęba lying in the ditch along the road in Tarnowska Wola. At the hospital, it was recorded that the man had a blood alcohol content of 1.374%. The man survived. | 1 | Biochemistry |
Research on accurately modeling rates of mutation has been conducted for many years. A recent paper by Ziheng Yang and Rasmus Nielsen compared various methods and developed a new modeling method. They found that the new method was preferable for its smaller biases, which make it useful for large scale screening, but that the maximum-likelihood model was preferable in most scenarios because of its simplicity, and its flexibility in comparing multiple sequences while taking into account phylogeny.
Further research by Yang and Nielsen found that nonsynonymous to synonymous substitution ratios varied across loci in differing evolutionary lineages. During their study of nuclear loci of primates, even-toed ungulates, and rodents, they found that the ratio varied significantly at 22 of the 48 loci studied. This result provides strong evidence against a strictly neutral theory of molecular evolution, which states that mutations are mostly neutral or deleterious, and provides support for theories that include advantageous mutations. | 1 | Biochemistry |
The Kinetic PreProcessor (KPP) is an open-source software tool used in atmospheric chemistry. Taking a set of chemical reactions and their rate coefficients as input, KPP generates Fortran 90, FORTRAN 77, C, or Matlab code
of the resulting ordinary differential equations (ODEs). Solving the ODEs allows the temporal integration of the kinetic system. Efficiency is obtained by exploiting the sparsity structures of the Jacobian and of the Hessian. A comprehensive suite of stiff numerical integrators is also provided. Moreover, KPP can be used to generate the tangent linear model, as well as the continuous and discrete adjoint models of the chemical system. | 7 | Physical Chemistry |
The U.S. Food and Drug Administration (FDA) approved tramadol in March 1995, and an extended-release (ER) formulation in September 2005. ER Tramadol was protected by US patents nos. 6,254,887 and 7,074,430. The FDA listed the patents' expiration as 10 May 2014. However, in August 2009, US District Court for the District of Delaware ruled the patents invalid, a decision upheld the following year by the Court of Appeals for the Federal Circuit. Manufacture and distribution of generic equivalents of Ultram ER in the United States was therefore permitted prior to the expiration of the patents. | 4 | Stereochemistry |
TNP-ATP is a fluorescent molecule that is able to determine whether a protein binds to ATP, and the constants associated with that binding. It is primarily used in fluorescence spectroscopy, but is also very useful as an acceptor molecule in FRET, and as a fluorescent probe in fluorescence microscopy and X-ray crystallography. | 7 | Physical Chemistry |
Bacteriophage Φ6, is a member of the Cystoviridae family. It infects Pseudomonas bacteria (typically plant-pathogenic P. syringae). It has a three-part, segmented, double-stranded RNA genome, totalling ~13.5 kb in length. Φ6 and its relatives have a lipid membrane around their nucleocapsid, a rare trait among bacteriophages. It is a lytic phage, though under certain circumstances has been observed to display a delay in lysis which may be described as a "carrier state". | 1 | Biochemistry |
SIDIS measurements were pioneered at DESY by the HERMES experiment. They are currently (2021) being carried out at CERN by the COMPASS experiment and several experiments at Jefferson Lab. SIDIS will be an important technique used in the future Electron Ion Collider scientific program. | 7 | Physical Chemistry |
The Mission of the International Deep Drawing Research Group ([http://www.iddrg.com IDDRG]) is to co-ordinate research and development work in sheet metal forming, to bring together scientists, researchers and industrialists working on these fields all over the World, to provide open and scientifically highly acknowledged forum to its members to present their research and development findings on all aspects of sheet metal forming and certain related subjects.
The combination of technical presentations and opportunities for discussion are meant to stimulate thinking and to provide valuable interchange of ideas. | 8 | Metallurgy |
Trifluoromethyltrimethylsilane (known as Ruppert-Prakash reagent, TMSCF) is an organosilicon compound with the formula CFSi(CH). It is a colorless liquid. The compound is a reagent used in organic chemistry for the introduction of the trifluoromethyl group. The compound was first prepared in 1984 by Ingo Ruppert and further developed as a reagent by G. K. Surya Prakash. | 0 | Organic Chemistry |
Alkyl groups have a low to zero value for F but sensible values for R. This is most commonly explained by hyperconjugation, meaning little to no inductive effects but partial resonance effects.
CF has a much higher R/F ratio than other substituents with high degrees of conjugation. This was studied in greater detail by Swain but is still explained best by fluoride hyperconjugation.
Positively charged substituents (i.e., and ) have larger positive F values due to a positive charge that is saturated near the carbon framework in question. Negatively charged substituents (i.e., CO and SO) have much lower F values because of their ability to resonate electron density amongst the oxygen atoms and stabilize it through hydrogen-bonding with solvents.
Linear free energy relationships are still useful, despite their disadvantages when pushed to the limits. New techniques to solve for Swain–Lupton substituent parameters involve studying chemical shifts through nuclear magnetic resonance spectroscopy. Recently, N NMR chemical shifts and substituent effects of 1,2,3,4,5,6,7,8-octahydroacridine and derivatives were studied. Values for R and F were found for the group, which could not be found previously using known methods. | 7 | Physical Chemistry |
Synthetic approaches to CYN started with the piperidine ring (A), and progressed to annulation of rings B and C. The first total synthesis of CYN was reported in 2000 through a 20-step process.
Improvements to synthetic methods led to a revision of the stereochemistry of CYN in 2001. A synthetic process controlling each of the six stereogenic centres of epiCYN established that the original assignments of both CYN and epiCYN were in fact a reversal of the correct structures. An alternative approach by White and Hansen supported these absolute configurations (Figure 5). At the time of this correct assignment, it was suggested that the enol form was not dominant. | 0 | Organic Chemistry |
Uranium rhodium germanium (URhGe) is the first discovered metal that becomes superconducting in the presence of an extremely strong electromagnetic field. Very unlike other superconducting materials, whose superconducting properties can be lost due to strong magnetic fields, uranium rhodium germanium actually regains superconducting abilities at about 8 teslas. | 8 | Metallurgy |
The nine-membered enediynes are also referred to as chromoproteins because they have an attached protein as a variable group. This protein is necessary for transport and stabilization of the enediyne group. | 0 | Organic Chemistry |
Sometime during human evolution, exogenous progenitors of HERV inserted themselves into germ line cells and then replicated along with the hosts genes using and exploiting the hosts cellular mechanisms. Because of their distinct genomic structure, HERVs were subjected to many rounds of amplification and transposition, which lead to a more widespread distribution of retroviral DNA.
Nevertheless, one family of viruses has been active since the divergence of humans and chimpanzees. This family, termed HERV-K (HML2), makes up less than 1% of HERV elements but is one of the most studied. There are indications it has even been active in the past few hundred thousand years, e.g., some human individuals carry more copies of HML2 than others. Traditionally, age estimates of HERVs are performed by comparing the 5 and 3 LTR of a HERV; however, this method is only relevant for full-length HERVs. A recent method, called cross-sectional dating, uses variations within a single LTR to estimate the ages of HERV insertions. This method is more precise in estimating HERV ages and can be used for any HERV insertions. Cross-sectional dating has been used to suggest that two members of HERV-K (HML2), HERV-K106 and HERV-K116, were active in the last 800,000 years and that HERV-K106 may have infected modern humans 150,000 years ago. However, the absence of known infectious members of the HERV-K (HML2) family, and the lack of elements with a full coding potential within the published human genome sequence, suggests to some that the family is less likely to be active at present. In 2006 and 2007, researchers working independently in France and the US recreated functional versions of HERV-K (HML2). | 1 | Biochemistry |
Many sulfonic acids are prepared by hydrolysis of sulfonyl halides and related precursors. Thus, perfluorooctanesulfonic acid is prepared by hydrolysis of the sulfonyl fluoride, which in turn is generated by the electrofluorination of octanesulfonic acid. Similarly the sulfonyl chloride derived from polyethylene is hydrolyzed to the sulfonic acid. These sulfonyl chlorides are produced by free-radical reactions of chlorine, sulfur dioxide, and the hydrocarbons using the Reed reaction.
Vinylsulfonic acid is derived by hydrolysis of carbyl sulfate, (), which in turn is obtained by the addition of sulfur trioxide to ethylene. | 0 | Organic Chemistry |
For US food and dietary supplement labeling purposes the amount in a serving is expressed as a percent of Daily Value (%DV). For selenium labeling purposes 100% of the Daily Value was 70 μg, but as of May 27, 2016 it was revised to 55 μg. A table of the old and new adult daily values is provided at Reference Daily Intake. | 1 | Biochemistry |
The process of elongation is the synthesis of a copy of the DNA into messenger RNA. RNA Pol II matches complementary RNA nucleotides to the template DNA by Watson-Crick base pairing. These RNA nucleotides are ligated, resulting in a strand of messenger RNA.
Unlike DNA replication, mRNA transcription can involve multiple RNA polymerases on a single DNA template and multiple rounds of transcription (amplification of particular mRNA), so many mRNA molecules can be rapidly produced from a single copy of a gene.
Elongation also involves a proofreading mechanism that can replace incorrectly incorporated bases. In eukaryotes, this may correspond with short pauses during transcription that allow appropriate RNA editing factors to bind. These pauses may be intrinsic to the RNA polymerase or due to chromatin structure. | 1 | Biochemistry |
Schisandra chinensis (S. chinensis) berries, originally a component of traditional herbal medicine in China, Korea, and other east Asian countries, are also valuable agents in modern phototherapy. S. chinensis berry preparations, including extracts and their chemical components, demonstrate anti-cancer, hepatoprotective, anti-inflammatory, and antioxidant properties, among others. These valuable properties, and their therapeutic potential, are conditioned by the unique chemical composition of S. chinensis berries, particularly their lignan content. About 40 of these compounds, mainly dibenzocyclooctane type, were isolated from S. chinensis. The most important bioactive lignans are schisandrin (also denoted as schizandrin or schisandrol A), schisandrin B, schisantherin A, schisantherin B, schisanhenol, deoxyschisandrin, and gomisin A. The present work reviews newly-available literature concerning the cardioprotective potential of S. chinensis berries and their individual components. It places special emphasis on the cardioprotective properties of the selected lignans related to their antioxidant and anti-inflammatory characteristis.
Examples include:
* Schisandrin A
* Schisandrin B (γ-schisandrin)
* Schisandrin C | 0 | Organic Chemistry |
Formed by the retreat of the glaciers at the end of the last Ice Age, Frame Lake remained a relatively pure lake even as the area was settled and modern development impinged on it. The closure of its only outlet around 1970, however, led swiftly to its decline and eutrophication. By the end of the 20th century it could no longer support fish and was not being used for primary recreational purposes. Attempts to revive it started in the 2010s. | 2 | Environmental Chemistry |
The Catholic Church opposes all kinds of assisted reproductive technology and artificial contraception, on the grounds that they separate the procreative goal of marital sex from the goal of uniting married couples.
The Catholic Church permits the use of a small number of reproductive technologies and contraceptive methods such as natural family planning, which involves charting ovulation times, and allows other forms of reproductive technologies that allow conception to take place from normative sexual intercourse, such as a fertility lubricant. Pope Benedict XVI had publicly re-emphasised the Catholic Church's opposition to in vitro fertilisation, saying that it replaces love between a husband and wife.
The Catechism of the Catholic Church, in accordance with the Catholic understanding of natural law, teaches that reproduction has an "inseparable connection" to the sexual union of married couples. In addition, the church opposes IVF because it might result in the disposal of embryos; in Catholicism, an embryo is viewed as an individual with a soul that must be treated as a person. The Catholic Church maintains that it is not objectively evil to be infertile, and advocates adoption as an option for such couples who still wish to have children.
Hindus welcome IVF as a gift for those who are unable to bear children and have declared doctors related to IVF to be conducting punya as there are several characters who were claimed to be born without intercourse, mainly Kaurav and five Pandavas.
Regarding the response to IVF by Islam, a general consensus from the contemporary Sunni scholars concludes that IVF methods are immoral and prohibited. However, Gad El-Hak Ali Gad El-Hak's ART fatwa includes that:
*IVF of an egg from the wife with the sperm of her husband and the transfer of the fertilised egg back to the uterus of the wife is allowed, provided that the procedure is indicated for a medical reason and is carried out by an expert physician.
*Since marriage is a contract between the wife and husband during the span of their marriage, no third party should intrude into the marital functions of sex and procreation. This means that a third party donor is not acceptable, whether he or she is providing sperm, eggs, embryos, or a uterus. The use of a third party is tantamount to zina, or adultery.
Within the Orthodox Jewish community the concept is debated as there is little precedent in traditional Jewish legal textual sources. Regarding laws of sexuality, religious challenges include masturbation (which may be regarded as "seed wasting"), laws related to sexual activity and menstruation (niddah) and the specific laws regarding intercourse. An additional major issue is that of establishing paternity and lineage. For a baby conceived naturally, the fathers identity is determined by a legal presumption (chazakah) of legitimacy: rov biot achar habaal – a womans sexual relations are assumed to be with her husband. Regarding an IVF child, this assumption does not exist and as such Rabbi Eliezer Waldenberg (among others) requires an outside supervisor to positively identify the father. Reform Judaism has generally approved IVF. | 1 | Biochemistry |
Both ASR and aerial respiration require fish to travel to the top of water column and this behaviour increases the predation risks by aerial predators or other piscivores inhabiting near the surface of the water. To cope with the increased predation risk upon surfacing, some fish perform ASR or aerial respiration in schools to dilute the predation risk. When fish can visually detect the presence of their aerial predators, they simply refrain from surfacing, or prefer to surface in areas where they can be detected less easily (i.e. turbid, shaded areas). | 9 | Geochemistry |
In radiobiology a broad or focused ion beam is used to study mechanisms of inter- and intra- cellular communication, signal transduction and DNA damage and repair. | 7 | Physical Chemistry |
Iron ores are overwhelmingly derived from ancient sediments known as banded iron formations (BIFs). These sediments are composed of iron oxide minerals deposited on the sea floor. Particular environmental conditions are needed to transport enough iron in sea water to form these deposits, such as acidic and oxygen-poor atmospheres within the Proterozoic Era.
Often, more recent weathering is required to convert the usual magnetite minerals into more easily processed hematite. Some iron deposits within the Pilbara of Western Australia are placer deposits, formed by accumulation of hematite gravels called pisolites which form channel-iron deposits. These are preferred because they are cheap to mine. | 9 | Geochemistry |
Short-chain CPs are classified as persistent and their physical properties (octanol-water partition coefficient (logK) 4.4–8, depending on the chlorination degree) imply a high potential for bioaccumulation. SCCPs are classified as toxic to aquatic organisms, and carcinogenic to rats and mice. Therefore, it was concluded that SCCPs have PBT and vPvB properties and they were added to the Candidate List of substances of very high concern for Authorisation under REACH Regulation. SCCPs (average chain length of C, chlorination degree 60 wt%) were categorised in group 2B as possibly carcinogenic to humans from the International Agency for Research on Cancer (IARC). In 2017, it was agreed to globally ban SCCPs under the Stockholm Convention on Persistent Organic Pollutants, effective December 2018. However, also MCCPs are toxic to the aquatic environment and persistent; MCCPs in soil, biota, and most of the sediment cores show increasing time trends over the last years to decades; MCCP concentrations in sediment close to local sources exceed toxicity thresholds such as the PNEC. In July 2021 also MCCPs were added to the Candidate List of Substances of Very High Concern (SVHC) under the REACH Regulation.
Chlorinated paraffins have been detected in marine life such as cetaceans (whales) and bivalves (molluscs). Of particular concern is fetal accumulation in whales, with the chemicals beginning to build-up in the offspring before they are even born. | 2 | Environmental Chemistry |
Elemental iodine is an oxidizing irritant, and direct contact with skin can cause lesions, so iodine crystals should be handled with care. Solutions with high elemental iodine concentration such as tincture of iodine are capable of causing tissue damage if use for cleaning and antisepsis is prolonged. Although elemental iodine is used in the formulation of Lugols solution, a common medical disinfectant, it becomes triiodide upon reacting with the potassium iodide used in the solution and is therefore non-toxic. Only a small amount of elemental iodine will dissolve in water, but triiodides are highly soluble; potassium iodide thus serves as a phase transfer catalyst in the tincture. This allows Lugols iodine to be produced in strengths varying from 2% to 15% iodine.
Elemental iodine (I) is poisonous if taken orally in large amounts; 2–3 grams is a lethal dose for an adult human.
Iodine vapor is very irritating to the eye, to mucous membranes, and in the respiratory tract. Concentration of iodine in the air should not exceed 1 mg/m (eight-hour time-weighted average).
When mixed with ammonia and water, elemental iodine forms nitrogen triiodide, which is extremely shock-sensitive and can explode unexpectedly. | 1 | Biochemistry |
In botany, a stoma (: stomata, from Greek στόμα, "mouth"), also called a stomate (: stomates), is a pore found in the epidermis of leaves, stems, and other organs, that controls the rate of gas exchange between the internal air spaces of the leaf and the atmosphere. The pore is bordered by a pair of specialized parenchyma cells known as guard cells that regulate the size of the stomatal opening.
The term is usually used collectively to refer to the entire stomatal complex, consisting of the paired guard cells and the pore itself, which is referred to as the stomatal aperture. Air, containing oxygen, which is used in respiration, and carbon dioxide, which is used in photosynthesis, passes through stomata by gaseous diffusion. Water vapour diffuses through the stomata into the atmosphere as part of a process called transpiration.
Stomata are present in the sporophyte generation of the vast majority of land plants, with the exception of liverworts, as well as some mosses and hornworts. In vascular plants the number, size and distribution of stomata varies widely. Dicotyledons usually have more stomata on the lower surface of the leaves than the upper surface. Monocotyledons such as onion, oat and maize may have about the same number of stomata on both leaf surfaces. In plants with floating leaves, stomata may be found only on the upper epidermis and submerged leaves may lack stomata entirely. Most tree species have stomata only on the lower leaf surface. Leaves with stomata on both the upper and lower leaf surfaces are called amphistomatous leaves; leaves with stomata only on the lower surface are hypostomatous, and leaves with stomata only on the upper surface are epistomatous or hyperstomatous. Size varies across species, with end-to-end lengths ranging from 10 to 80 µm and width ranging from a few to 50 µm. | 5 | Photochemistry |
The IsaKidd Technology is a copper electrorefining and electrowinning technology that was developed independently by Copper Refineries Proprietary Limited (“CRL”), a Townsville, Queensland, subsidiary of MIM Holdings Limited (which is now part of the Glencore group of companies), and at the Falconbridge Limited (“Falconbridge”) now-dismantled Kidd Creek refinery that was at Timmins, Ontario. It is based around the use of reusable cathode starter sheets for copper electrorefining and the automated stripping of the deposited “cathode copper” from them. | 8 | Metallurgy |
Disorders of fatty acid metabolism can be described in terms of, for example, hypertriglyceridemia (too high level of triglycerides), or other types of hyperlipidemia. These may be familial or acquired.
Familial types of disorders of fatty acid metabolism are generally classified as inborn errors of lipid metabolism. These disorders may be described as fatty acid oxidation disorders or as a lipid storage disorders, and are any one of several inborn errors of metabolism that result from enzyme or transport protein defects affecting the ability of the body to oxidize fatty acids in order to produce energy within muscles, liver, and other cell types. When a fatty acid oxidation disorder affects the muscles, it is a metabolic myopathy.
Moreover, cancer cells can display irregular fatty acid metabolism with regard to both fatty acid synthesis and mitochondrial fatty acid oxidation (FAO) that are involved in diverse aspects of tumorigenesis and cell growth. | 1 | Biochemistry |
A Grotrian diagram, or term diagram, shows the allowed electronic transitions between the energy levels of atoms. They can be used for one-electron and multi-electron atoms. They take into account the specific selection rules related to changes in angular momentum of the electron. The diagrams are named after Walter Grotrian, who introduced them in his 1928 book Graphische Darstellung der Spektren von Atomen und Ionen mit ein, zwei und drei Valenzelektronen ("Graphical representation of the spectra of atoms and ions with one, two and three valence electrons"). | 7 | Physical Chemistry |
Photodynamic detection is the use of photosensitive drugs with a light source of the right wavelength for the detection of cancer, using fluorescence of the drug. 5ALA, or derivatives thereof, can be used to visualize bladder cancer by fluorescence imaging. | 1 | Biochemistry |
Brenna was the key expert witness in the action of the United States Anti-Doping Agency (USADA) against 2006 Tour de France first place finisher Floyd Landis, adjudicated in a hearing of the Tribunal Arbitral du Sport/Court for Arbitration in Sport held in Malibu, California. He testified to the accuracy of Carbon Isotope Ratio (CIR) tests conducted by the French Antidoping laboratory at Châtenay-Malabry. Landis conducted a high profile, multimillion dollar defense but lost the 2007 original hearing with the decision relying for technical opinion on Brenna’s testimony. Landis later lost a 2008 de novo case before the American Arbitration Association also relying on Brenna’s testimony and was stripped of his title. Years later Landis revealed he was doping and filed a whistle-blower lawsuit under the federal False Claims Act against Lance Armstrong that was settled with multimillion dollar payments by Armstrong. | 3 | Analytical Chemistry |
There have been cases where people died after eating foods containing palytoxin or poisons similar to it. In the Philippines people died after eating Demania crabs. After eating bluestripe herring some people died in Madagascar. People who had eaten smoked mackerel and parrotfish experienced near fatal poisoning in Hawaii and Japan respectively. | 0 | Organic Chemistry |
The process of soil formation is dominated by chemical weathering of silicate minerals, aided by acidic products of pioneering plants and organisms as well as carbonic acid inputs from the atmosphere. Carbonic acid is produced in the atmosphere and soil layers through the carbonation reaction.
This is the dominant form of chemical weathering and aides in the breakdown of carbonate minerals (such as calcite and dolomite) and silicate minerals (such as feldspar). The breakdown of the Na-feldspar, albite, by carbonic acid to form kaolinite clay is as follows:
Evidence of this reaction in the field would be elevated levels of bicarbonate (), sodium and silica ions in the water runoff.
The breakdown of carbonate minerals:
The further dissolution of carbonic acid (HCO) and bicarbonate () produces CO gas. Oxidization is also a major contributor to the breakdown of many silicate minerals and formation of secondary minerals (diagenesis) in the early soil profile. Oxidation of olivine (FeMgSiO) releases Fe, Mg and Si ions. The Mg is soluble in water and is carried in the runoff, but the Fe often reacts with oxygen to precipitate FeO (hematite), the oxidized state of iron oxide. Sulfur, a byproduct of decaying organic material, will also react with iron to form pyrite (FeS) in reducing environments. Pyrite dissolution leads to low pH levels due to elevated H ions and further precipitation of FeO ultimately changing the redox conditions of the environment. | 9 | Geochemistry |
Condensation with ketones and aldehydes yields the corresponding N-tert-butanesulfinyl aldimines and ketimines. These intermediates are more resistant to hydrolysis than other imines but more reactive towards nucleophiles. A nucleophile adds diastereoselectively over the imine group in an electrophilic addition with the tert-butanesulfinyl group acting as a chiral auxiliary. This tert-butanesulfinyl group is also a protecting group. On addition of hydrochloric acid the tert-butanesulfinyl group is removed, forming the chiral primary ammonium salt or amine (from aldehyde precursor) or the chiral secondary amine (ketone precursor).
Typical nucleophiles are Grignard reagents, organozinc compounds, organolithium compounds, and enolates.
Chiral sulfinimines as intermediates for the asymmetric synthesis of amines have also been developed by Franklin A. Davis. | 0 | Organic Chemistry |
Defects in the erythropoietin receptor may produce erythroleukemia and familial erythrocytosis. Overproduction of red blood cells increases a chance of adverse cardiovascular event, such as thrombosis and stroke.
Rarely, seemingly beneficial mutations in the EpoR may arise, where increased red blood cell number allows for improved oxygen delivery in athletic endurance events with no apparent adverse effects upon the athlete's health (as for example in the Finnish athlete Eero Mäntyranta).
Erythropoietin was reported to maintain endothelial cells and to promote tumor angiogenesis, hence the dysregulation of EpoR may affect the growth of certain tumors. However this hypothesis is not universally accepted. | 1 | Biochemistry |
Macrocyclic rings containing sp centers display a conformational preference for the sp centers to avoid transannular nonbonded interactions by orienting perpendicular to the plan of the ring. Clark W. Still proposed that the ground state conformations of macrocyclic rings, containing the energy minimized orientation of the sp center, display one face of an olefin outwards from the ring. Addition of reagents from the outside the olefin face and the ring (peripheral attack) is thus favored, while attack from across the ring on the inward diastereoface is disfavored. Ground state conformations dictate the exposed face of the reactive site of the macrocycle, thus both local and distant stereocontrol elements must be considered. The peripheral attack model holds well for several classes of macrocycles, though relies on the assumption that ground state geometries remain unperturbed in the corresponding transition state of the reaction. | 0 | Organic Chemistry |
, where is the enthalpy of the liquid and is the enthalpy of the vapour
By substituting the mass balance equation in above equation we get the following expression: | 3 | Analytical Chemistry |
Intelectins are lectins (carbohydrate-binding proteins) expressed in humans and other chordates. Humans express two types of intelectins encoded by ITLN1 and ITLN2 genes respectively. Several intelectins bind microbe-specific carbohydrate residues. Therefore, intelectins have been proposed to function as immune lectins. Even though intelectins contain fibrinogen-like domain found in the ficolins family of immune lectins, there is significant structural divergence. Thus, intelectins may not function through the same lectin-complement pathway. Most intelectins are still poorly characterized and they may have diverse biological roles. Human intelectin-1 (hIntL-1) has also been shown to bind lactoferrin, but the functional consequence has yet to be elucidated. Additionally, hIntL-1 is a major component of asthmatic mucus and may be involved in insulin physiology as well. | 1 | Biochemistry |
In chemistry, a reaction intermediate, or intermediate, is a molecular entity arising within the sequence of a stepwise chemical reaction. It is formed as the reaction product of an elementary step, from the reactants and/or preceding intermediates, but is consumed in a later step. It does not appear in the chemical equation for the overall reaction.
For example, consider this hypothetical reaction:
:A + B → C + D
If this overall reaction comprises two elementary steps thus:
:A + B → X
:X → C + D
then X is a reaction intermediate.
The phrase itself, reaction intermediate, is very often abbreviated to the single word intermediate, and this is IUPAC's preferred form of the term. But this shorter form has other uses. It often refers to reactive intermediates. It is also used more widely for chemicals such as cumene which are traded within the chemical industry but are not generally of value outside it. | 7 | Physical Chemistry |
The analytical determination of a functional additive has particular problems associated with it. The concentration of a functional additive may be low compared to other ingredients; therefore, it may be difficult to detect. Proprietary ingredients are especially difficult to correctly identify. The functional role of a key component may not be obvious upon inspection. A key ingredient may be undisclosed by the maker of the material, but rather kept as a trade secret. Careful study of trade literature and patent filings associated with the manufacturer may aid the analyst in the characterization. | 3 | Analytical Chemistry |
Although vitamin D is present naturally in only a few foods, it is commonly added as a fortification in manufactured foods. In some countries, staple foods are artificially fortified with vitamin D. | 1 | Biochemistry |
Fast Sulphon Black is purple when complexed with copper, and turns green when titrated against EDTA, as the EDTA displaces it, being the better complexing agent due to the chelate effect. | 3 | Analytical Chemistry |
Water quality refers to the chemical, physical, and biological characteristics of water based on the standards of its usage. It is most frequently used by reference to a set of standards against which compliance, generally achieved through treatment of the water, can be assessed. The most common standards used to monitor and assess water quality convey the health of ecosystems, safety of human contact, extent of water pollution and condition of drinking water. Water quality has a significant impact on water supply and oftentimes determines supply options. | 3 | Analytical Chemistry |
Another ancient idea dating back to Anaxagoras in the 5th century BC is panspermia, the idea that life exists throughout the universe, distributed by meteoroids, asteroids, comets and planetoids. It does not attempt to explain how life originated in itself, but shifts the origin of life on Earth to another heavenly body. The advantage is that life is not required to have formed on each planet it occurs on, but rather in a more limited set of locations (potentially even a single location), and then spread about the galaxy to other star systems via cometary or meteorite impact. | 9 | Geochemistry |
Two clades of dsRNA viruses exist: the phylum Duplornaviricota and the class Duplopiviricetes, which is in the phylum Pisuviricota. Both are included in the kingdom Orthornavirae in the realm Riboviria. Based on phylogenetic analysis of RdRp, the two clades do not share a common dsRNA ancestor but are instead separately descended from different positive-sense, single-stranded RNA viruses. In the Baltimore classification system, which groups viruses together based on their manner of mRNA synthesis, dsRNA viruses are group III. | 1 | Biochemistry |
CAF formation is a process involving the transport of conductive chemistries across a nonmetallic substrate under the influence of an applied electric field. CAF is influenced by electric field strength, temperature (including soldering temperatures), humidity, laminate material, and the presence of manufacturing defects. The occurrence of CAF failures has been primarily driven by the electronics industry pushing for higher density circuit boards and the use of electronics in harsher environments for high reliability applications. | 7 | Physical Chemistry |
Photoelectrochemistry has been intensively studied in the field of hydrogen production from water and solar energy. The photoelectrochemical splitting of water was historically discovered by Fujishima and Honda in 1972 onto TiO electrodes. Recently many materials have shown promising properties to split efficiently water but TiO remains cheap, abundant, stable against photo-corrosion. The main problem of TiO is its bandgap which is 3 or 3.2 eV according to its crystallinity (anatase or rutile). These values are too high and only the wavelength in the UV region can be absorbed. To increase the performances of this material to split water with solar wavelength, it is necessary to sensitize the TiO. Currently Quantum Dots sensitization is very promising but more research is needed to find new materials able to absorb the light efficiently. | 5 | Photochemistry |
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