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Commercially available salts thiamine chloride and thiamine nitrate are produced at scales of thousands of tons annually by chemistry-based manufacturing processes in Europe and Asia. These salts are supplied for formulations for supplementation of human diet and as feed additives for cattle, swine, poultry and fish. Research for potential biotechnology-based production of thiamine has resulted in patent applications claiming fermentation using recombinant microorganisms modified to deregulate feedback inhibition and allow release of thiamine forms to the media as demonstrated at small scale. Thiamine forms and their bio-precursors are produced at very large scale in biological matrices such as yeast, grains, plants and meats widely consumed as food and feed. Research into genetic modification of plants. has led to higher levels of thiamine in foodstuffs, such as rice. Use of thiamine forms and their bio-precursors by various means such as seed coating or soil and foliar fertilization to improve plant growth and properties are being investigated.

Biochemistry

Trifluoroperacetic acid can be easily prepared by an Organic Syntheses process of treating trifluoroacetic anhydride with a concentrated (90%) aqueous solution of hydrogen peroxide: :trifluoroacetic anhydride| + hydrogen peroxide| → + trifluoroacetic acid| As the anhydride will form trifluoroacetic acid in contact with water, an excess of the anhydride also serves to remove the solvent from the peroxide reactant: : + water| → 2 A more dilute hydrogen peroxide solution (30%) can be used to form trifluoroperacetic acid for some reactions from trifluoroacetic acid. In order to avoid the danger of handling pure or highly concentrated solutions of hydrogen peroxide, hydrogen peroxide – urea can be used to give the peracid. This method involves no water, so it gives a completely anhydrous peracid, which is an advantage when the presence of water leads to side reactions during certain oxidation reactions. : + hydrogen peroxide - urea| → + + urea| In cases where a pH buffering agent is needed for a synthesis and where the presence of water is tolerated, another approach has been developed. Reacting trifluoroacetic anhydride with sodium percarbonate, , yields trifluoroperacetic acid and sodium carbonate, obviating the need for an additional buffer. :3 + 4 sodium percarbonate| → 6 + 4 sodium carbonate| + 3 Trifluoroperacetic acid can also be generated in situ, allowing it to react promptly with the target substrate rather than pre-synthesizing a batch of the reagent for later use.

Organic Chemistry

In matrix-assisted laser desorption and ionization (MALDI), the sample is incorporated in a chemical matrix that is capable of absorbing energy from a laser. Similar to SIMS, ionization happens in vacuum. Laser irradiation ablates the matrix material from the surface and results in charged gas phase matrix particles, the analyte molecules are ionized from this charged chemical matrix. Liu et al. used MALDI-MS to detect eight phospholipids from single A549 cells. MALDI MS imaging can be used for spatial metabolomics and single cell analysis.

Biochemistry

There are a number of disorders which disrupt normal functioning of ion channels and have disastrous consequences for the organism. Genetic and autoimmune disorders of ion channels and their modifiers are known as channelopathies. See :Category:Channelopathies for a full list. * Shaker gene mutations cause a defect in the voltage gated ion channels, slowing down the repolarization of the cell. * Equine hyperkalaemic periodic paralysis as well as human hyperkalaemic periodic paralysis (HyperPP) are caused by a defect in voltage-dependent sodium channels. * Paramyotonia congenita (PC) and potassium-aggravated myotonias (PAM) * Generalized epilepsy with febrile seizures plus (GEFS+) * Episodic ataxia (EA), characterized by sporadic bouts of severe discoordination with or without myokymia, and can be provoked by stress, startle, or heavy exertion such as exercise. * Familial hemiplegic migraine (FHM) * Spinocerebellar ataxia type 13 * Long QT syndrome is a ventricular arrhythmia syndrome caused by mutations in one or more of presently ten different genes, most of which are potassium channels and all of which affect cardiac repolarization. * Brugada syndrome is another ventricular arrhythmia caused by voltage-gated sodium channel gene mutations. * Polymicrogyria is a developmental brain malformation caused by voltage-gated sodium channel and NMDA receptor gene mutations. * Cystic fibrosis is caused by mutations in the CFTR gene, which is a chloride channel. * Mucolipidosis type IV is caused by mutations in the gene encoding the TRPML1 channel * Mutations in and overexpression of ion channels are important events in cancer cells. In Glioblastoma multiforme, upregulation of gBK potassium channels and ClC-3 chloride channels enables glioblastoma cells to migrate within the brain, which may lead to the diffuse growth patterns of these tumors.

Biochemistry

The increase in intensity of the Raman signal for adsorbates on particular surfaces occurs because of an enhancement in the electric field provided by the surface. When the incident light in the experiment strikes the surface, localized surface plasmons are excited. The field enhancement is greatest when the plasmon frequency, ω, is in resonance with the radiation ( for spherical particles). In order for scattering to occur, the plasmon oscillations must be perpendicular to the surface; if they are in-plane with the surface, no scattering will occur. It is because of this requirement that roughened surfaces or arrangements of nanoparticles are typically employed in SERS experiments as these surfaces provide an area on which these localized collective oscillations can occur. SERS enhancement can occur even when an excited molecule is relatively far apart from the surface which hosts metallic nanoparticles enabling surface plasmon phenomena. The light incident on the surface can excite a variety of phenomena in the surface, yet the complexity of this situation can be minimized by surfaces with features much smaller than the wavelength of the light, as only the dipolar contribution will be recognized by the system. The dipolar term contributes to the plasmon oscillations, which leads to the enhancement. The SERS effect is so pronounced because the field enhancement occurs twice. First, the field enhancement magnifies the intensity of incident light, which will excite the Raman modes of the molecule being studied, therefore increasing the signal of the Raman scattering. The Raman signal is then further magnified by the surface due to the same mechanism that excited the incident light, resulting in a greater increase in the total output. At each stage the electric field is enhanced as E, for a total enhancement of E. The enhancement is not equal for all frequencies. For those frequencies for which the Raman signal is only slightly shifted from the incident light, both the incident laser light and the Raman signal can be near resonance with the plasmon frequency, leading to the E enhancement. When the frequency shift is large, the incident light and the Raman signal cannot both be on resonance with ω, thus the enhancement at both stages cannot be maximal. The choice of surface metal is also dictated by the plasmon resonance frequency. Visible and near-infrared radiation (NIR) are used to excite Raman modes. Silver and gold are typical metals for SERS experiments because their plasmon resonance frequencies fall within these wavelength ranges, providing maximal enhancement for visible and NIR light. Copper's absorption spectrum also falls within the range acceptable for SERS experiments. Platinum and palladium nanostructures also display plasmon resonance within visible and NIR frequencies.

Physical Chemistry

Cell–cell interaction refers to the direct interactions between cell surfaces that play a crucial role in the development and function of multicellular organisms. These interactions allow cells to communicate with each other in response to changes in their microenvironment. This ability to send and receive signals is essential for the survival of the cell. Interactions between cells can be stable such as those made through cell junctions. These junctions are involved in the communication and organization of cells within a particular tissue. Others are transient or temporary such as those between cells of the immune system or the interactions involved in tissue inflammation. These types of intercellular interactions are distinguished from other types such as those between cells and the extracellular matrix. The loss of communication between cells can result in uncontrollable cell growth and cancer.

Biochemistry

Ioliomics (from a portmanteau of ions and liquids) is the study of ions in liquids (or liquid phases) and stipulated with fundamental differences of ionic interactions. Ioliomics covers a broad research area concerning structure, properties and applications of ions involved in various biological and chemical systems. The concept of this research discipline is related to other comprehensive research fields, such as genomics, proteomics, glycomics, petroleomics, etc., where the suffix -omics is used for describing the comprehensiveness of data.

Biochemistry

Hemiacetals and hemiketals may be thought of as intermediates in the reaction between alcohols and aldehydes or ketones, with the final product being an acetal or a ketal: :RC=O + ROH ⇌ RC(OH)(OR) :RC(OH)(OR) + ROH ⇌ RC(OR') + HO Usually, the second reaction is unfavorable. In the presence of a dehydrating agent, it proceeds.

Organic Chemistry

Vitamin D is carried via the blood to the liver, where it is converted into the prohormone calcifediol. Circulating calcifediol may then be converted into calcitriol the biologically active form of vitamin D in the kidneys. Whether synthesized in the skin or ingested, vitamin D is hydroxylated in the liver at position 25 (upper right of the molecule) to form 25-hydroxycholecalciferol (calcifediol or 25(OH)D). This reaction is catalyzed by the microsomal enzyme vitamin D 25-hydroxylase, the product of the CYP2R1 human gene, and expressed by hepatocytes. Once made, the product is released into the plasma, where it is bound to an α-globulin carrier protein named the vitamin D-binding protein. Calcifediol is transported to the proximal tubules of the kidneys, where it is hydroxylated at the 1-α position (lower right of the molecule) to form calcitriol (1,25-dihydroxycholecalciferol, 1,25(OH)D). The conversion of calcifediol to calcitriol is catalyzed by the enzyme 25-hydroxyvitamin D 1-alpha-hydroxylase, which is the product of the CYP27B1 human gene. The activity of CYP27B1 is increased by parathyroid hormone, and also by low calcium or phosphate. Following the final converting step in the kidney, calcitriol is released into the circulation. By binding to vitamin D-binding protein, calcitriol is transported throughout the body, including to the intestine, kidneys, and bones. Calcitriol is the most potent natural ligand of the vitamin D receptor, which mediates most of the physiological actions of vitamin D. In addition to the kidneys, calcitriol is also synthesized by certain other cells, including monocyte-macrophages in the immune system. When synthesized by monocyte-macrophages, calcitriol acts locally as a cytokine, modulating body defenses against microbial invaders by stimulating the innate immune system.

Biochemistry

Fluoride (F) and acetate (CHCOO) anions are among the most important ones in the context of human health and well-being. The former, though used extensively in health care, is known for its toxicity and corrosiveness. The latter can cause alkalosis and affect metabolic pathways beyond a certain concentration. Hence, it is crucial to develop methods to detect these anions in aqueous media. Bhat et al. constructed an INHIBIT gate with receptors that bind selectively to F and CHCOO anions. The system used changes in absorbance as a colorimetric-based output to detect the concentration of anions.   Wen and coworkers also designed an INHIBIT molecular logic gate with Fe and EDTA as the inputs and a fluorescence output for the detection of ferric ions in solutions. The fluorescence of the system is quenched if and only if Fe input is present and EDTA is absent. Heavy metal ions provide a persistent threat to human health because of their inherent toxicity and low degradability. Several molecular logic gate-based systems have been constructed to detect ions such as Cd, Hg/Pb, and Ag. In their work, Chen and coworkers demonstrated that logic gate-based systems could be used to detect Cd ions in rice samples, thereby widening the scope of the field to safety detection in food materials, too.

Supramolecular Chemistry

George H. Miley is a professor of nuclear engineering and a cold fusion researcher who claims to have replicated the Patterson power cell. During the 2011 World Green Energy Symposium, Miley stated that his device continuously produces several hundred watts of power. Earlier results by Miley have not convinced mainstream researchers, who believe that they can be explained by contamination or by misinterpretation of data. On Good Morning America, Quintin Bowles, professor of mechanical engineering at the University of Missouri–Kansas City, claimed in 1996 to have successfully replicated the Patterson power cell. In the book Voodoo Science, Bowles is quoted as having stated: "It works, we just don't know how it works." A replication has been attempted at Earthtech, using a CETI supplied kit. They were not able to replicate the excess heat. They looked for cold fusion products, but only found traces of contamination in the electrolyte.

Physical Chemistry

The OEPCR method uses a small amount of the gene encoding the monomeric ELP unit and leads to the amplification of this segment to a great extent. This amplification is due to the fact that the initial segment added to the reaction functions as a template, from which identical gene segments can be synthesized. The process will result in the production of double-stranded DNA encoding the ELP of interest. One major bottleneck associated with this method is the potentially low fidelity associated with the Taq polymerase used. This might lead to replication from the template in which the wrong nucleotides are incorporated into the growing DNA strand.

Physical Chemistry

As of 2017, 7% of genetic therapy trials targeted infectious diseases. 69.2% of trials targeted HIV, 11% hepatitis B or C, and 7.1% malaria.

Biochemistry

Inevitably, [4+4] photocycloadditions carry the side reaction of [2+2] photocycloadditions. However, since these reactions are reversible, the most stable product may be formed through thermodynamic control.

Photochemistry

It is believed that thyroid hormones evolved in the Urbilaterian well before the development of the thyroid itself and molluscs, echinoderms, cephalochordates and ascidians all use such hormones. Cnidarians also respond to Thyroid hormone despite being parahoxozoans rather than bilaterians. Insects use hormones similar to thyroid hormone using iodine. Phosphorylated tyrosines created with tyrosine kinases are fundamental signalling molecules in all animals and in choanoflagellates.

Biochemistry

Weatherization generally does not cause indoor air quality problems by adding new pollutants to the air. (There are a few exceptions, such as caulking, that can sometimes emit pollutants.) However, measures such as installing storm windows, weather stripping, caulking, and blown-in wall insulation can reduce the amount of outdoor air infiltrating into a home. Consequently, after weatherization, concentrations of indoor air pollutants from sources inside the home can increase. Weatherization may have a negative impact on indoor air quality, if done improperly, exacerbating respiratory conditions especially among occupants with pre-existing respiratory illnesses. This may occur because of a drastic decrease in air exchange rate in the home, introduction of new chemicals, and poor management of indoor moisture due to a poorly performed weatherization work. Low air exchange rates may lead to higher concentrations of pollutants in the air when ventilation is not sufficiently addressed during weatherization work. However, the situation may be different in case of a house situated in an area with high outdoor air pollution levels such as in close proximity (<200 m) from a busy major road. In such a scenario, a more airtight building envelope can actually offer protection against infiltration of outdoor air pollution. The same is true for the protection offered by tighter building envelopes during wildfire events that cause elevated levels of outdoor air pollution.

Physical Chemistry

Solar energy conversion describes technologies devoted to the transformation of solar energy to other (useful) forms of energy, including electricity, fuel, and heat. It covers light-harvesting technologies including traditional semiconductor photovoltaic devices (PVs), emerging photovoltaics, solar fuel generation via electrolysis, artificial photosynthesis, and related forms of photocatalysis directed at the generation of energy rich molecules. Fundamental electro-optical aspects in several emerging solar energy conversion technologies for generation of both electricity (photovoltaics) and solar fuels constitute an active area of current research.

Physical Chemistry

Although the concept of U-value (or U-factor) is universal, U-values can be expressed in different units. In most countries, U-value is expressed in SI units, as watts per square metre-kelvin: :W/(m⋅K) In the United States, U-value is expressed as British thermal units (Btu) per hour-square feet-degrees Fahrenheit: :Btu/(h⋅ft⋅°F) Within this article, U-values are expressed in SI unless otherwise noted. To convert from SI to US customary values, divide by 5.678. Well-insulated parts of a have a low thermal transmittance whereas poorly insulated parts of a building have a high thermal transmittance. Losses due to thermal radiation, thermal convection and thermal conduction are taken into account in the U-value. Although it has the same units as heat transfer coefficient, thermal transmittance is different in that the heat transfer coefficient is used to solely describe heat transfer in fluids while thermal transmittance is used to simplify an equation that has several different forms of thermal resistances. It is described by the equation: :Φ = A × U × (T - T) where Φ is the heat transfer in watts, U is the thermal transmittance, T is the temperature on one side of the structure, T is the temperature on the other side of the structure and A is the area in square metres. Thermal transmittances most walls and roofs can be calculated using ISO 6946, unless there is metal bridging the insulation in which case it can be calculated using ISO 10211. For most ground floors it can be calculated using ISO 13370. For most windows the thermal transmittance can be calculated using ISO 10077 or ISO 15099. ISO 9869 describes how to measure the thermal transmittance of a structure experimentally. Choice of materials and quality of installation has a critical impact on the window insulation results. The frame and double sealing of the window system are the actual weak points in the window insulation. Typical thermal transmittance values for common building structures are as follows: *Single glazing: 5.7 W/(m⋅K) *Single glazed windows, allowing for frames: 4.5 W/(m⋅K) *Double glazed windows, allowing for frames: 3.3 W/(m⋅K) *Double glazed windows with advanced coatings: 2.2 W/(m⋅K) *Double glazed windows with advanced coatings and frames: 1.2 W/(m⋅K) *Triple glazed windows, allowing for frames: 1.8 W/(m⋅K) *Triple glazed windows, with advanced coatings and frames: 0.8 W/(m⋅K) *Well-insulated roofs: 0.10 W/(m⋅K) *Poorly insulated roofs: 1.0 W/(m⋅K) *Well-insulated walls: 0.15 W/(m⋅K) *Poorly insulated walls: 2 W/(m⋅K) *Well-insulated floors: 0.2 W/(m⋅K) *Poorly insulated floors: 1.0 W/(m⋅K) In practice the thermal transmittance is strongly affected by the quality of workmanship and if insulation is fitted poorly, the thermal transmittance can be considerably higher than if insulation is fitted well

Physical Chemistry

Immunomagnetic separation (IMS) is a laboratory tool that can efficiently isolate cells out of body fluid or cultured cells. It can also be used as a method of quantifying the pathogenicity of food, blood or feces. DNA analysis have supported the combined use of both this technique and Polymerase Chain Reaction (PCR). Another laboratory separation tool is the affinity magnetic separation (AMS), which is more suitable for the isolation of prokaryotic cells. IMS deals with the isolation of cells, proteins, and nucleic acids through the specific capture of biomolecules through the attachment of small-magnetized particles, beads, containing antibodies and lectins. These beads are coated to bind to targeted biomolecules, gently separated and goes through multiple cycles of washing to obtain targeted molecules bound to these super paramagnetic beads, which can differentiate based on strength of magnetic field and targeted molecules, are then eluted to collect supernatant and then are able to determine the concentration of specifically targeted biomolecules. IMS obtains certain concentrations of specific molecules within targeted bacteria. A mixture of cell population will be put into a magnetic field where cells then are attached to super paramagnetic beads, specific example are Dynabeads (4.5-μm), will remain once excess substrate is removed binding to targeted antigen. Dynabeads consists of iron-containing cores, which is covered by a thin layer of a polymer shell allowing the absorption of biomolecules. The beads are coated with primary antibodies, specific-specific antibodies, lectins, enzymes, or streptavidin; the linkage between magnetized beads coated materials are cleavable DNA linker cell separation from the beads when the culturing of cells is more desirable. Many of these beads have the same principles of separation; however, the presence and different strength s of magnetic fields requires certain sizes of beads, based on the ramifications of the separation of the cell population. The larger sized beads (>2μm) are the most commonly used range that was produced by Dynal (Dynal [UK] Ltd., Wirral, Mersyside, UK; Dynal, Inc., Lake Success, NY). Where as smaller beads (<100 nm) are mostly used for MACS system that was produced by Miltenyi Biotech (Miltenyi Biotech Ltd., Bisley, Surrey, UK; Miltenyi Biotech Inc., Auburn, CA). Immunomagnetic separation is used in a variety of scientific fields including molecular biology, microbiology, and immunology. (3) This technique of separation does not only consist of separation of cells within the blood, but can also be used for techniques of separation from primary tumors and in metastases research, through separation into component parts, creating a singular-cell delay, then allowing the suitable antibody to label the cell. In metastasis research this separation technique may become necessary to separate when given a cell population and wanting to isolate tumors cells in tumors, peripheral blood, and bone marrow.

Biochemistry

Using non-linear least squares minimization, the following system is solved: where is the calculated intensity and is the observed intensity of a point in the powder pattern, , is a scale factor, and is the number of measured data points. The minimized function is given by: where is the weight, and from the previous equation is unity (since is usually absorbed in the phase scale factor). The summation extends to all data points. Considering the peak shape functions and accounting for the overlapping of Bragg peaks because of the one-dimensionality of XRD data, the expanded form of the above equation for the case of a single phase measured with a single wavelength becomes: where: * is the background at the data point. * is the phase scale factor. * is the number of Bragg reflections contributing to the intensity of the reflection. * is the integrated intensity of the Bragg peak. * is the peak shape function. For a material that contains several phases (), the contribution from each is accounted for by modifying the above equation as follows: It can easily be seen from the above equations that experimentally minimizing the background, which holds no useful structural information, is paramount for a successful profile fitting. For a low background, the functions are defined by contributions from the integrated intensities and peak shape parameters. But with a high background, the function being minimized depends on the adequacy of the background and not integrated intensities or peak shapes. Thus, a structure refinement cannot adequately yield structural information in the presence of a large background. It is also worth noting the increased complexity brought forth by the presence of multiple phases. Each additional phase adds to the fitting, more Bragg peaks, and another scale factor tied to corresponding structural parameters, and peak shape. Mathematically they are easily accounted for, but practically, due to the finite accuracy and limited resolution of experimental data, each new phase can lower the quality and stability of the refinement. It is advantageous to use single phase materials when interested in finding precise structural parameters of a material. However, since the scale factors of each phase are determined independently, Rietveld refinement of multi phase materials can quantitatively examine the mixing ratio of each phase in the material.

Analytical Chemistry

Bahadurs publications were ambivalently received, and the overall attention of the scientific community seemed limited since Krishna Bahadur and his co-workers reported that the Jeewanus are alive (a striking statement), the team changed the protocols frequently and documented them somewhat idiosyncratically. Bahadur defined "living units" as "[...] those which grow, multiply, and are metabolically active in a systematic, harmonious, and synchronized manner". Then, NASAs Exobiology Division tasked two biologists in 1967 to review and evaluate the literature so far published by Krishna Bahadur (not to replicate the experiments) on the synthesis and characteristics of the Jeewanu. The two NASA biologists did not debate whether these three criteria are an adequate definition of life, but whether the Jeewanu satisfy these criteria. The NASA report concluded that "the evidence presented on these three points is on the whole unconvincing". The report also stated that the postulated existence of these living units has not been proved and "the nature and properties of the Jeewanu remains to be clarified." In the 1980s, the Hungarian chemist Tibor Gánti discussed the Jeewanu at length in his chemoton theory—an abstract model of autocatalytic chemical reactions—published first in Hungarian and translated into English in 2003. In the context of self-organizing structures, Gánti considered the Jeewanu a promising model system to understand the origin and fundamentals of life, and one that had never received due attention. In 2011, a German scientist stated that the Jeewanu story pertains to concepts of life, its beginnings, as well as possible artificially created cells. Experimental duplication work published in 2013 by Gupta and Rai reported that their size varies from 0.5 μ to 3.5 μ in diameter, growth from within, metabolic activities, and "the presence of RNA-like material". The authors stated that the RNA-like material detected in the Jeewanu protocells support the RNA world hypothesis.

Geochemistry

MRI has the advantages of having very high spatial resolution and is very adept at morphological imaging and functional imaging. MRI does have several disadvantages though. First, MRI has a sensitivity of around 10 mol/L mol/L which, compared to other types of imaging, can be very limiting. This problem stems from the fact that the difference between atoms in the high energy state and the low energy state is very small. For example, at 1.5 tesla, a typical field strength for clinical MRI, the difference between high and low energy states is approximately 9 molecules per 2 million. Improvements to increase MR sensitivity include increasing magnetic field strength, and hyperpolarization via optical pumping or dynamic nuclear polarization. There are also a variety of signal amplification schemes based on chemical exchange that increase sensitivity. To achieve molecular imaging of disease biomarkers using MRI, targeted MRI contrast agents with high specificity and high relaxivity (sensitivity) are required. To date, many studies have been devoted to developing targeted-MRI contrast agents to achieve molecular imaging by MRI. Commonly, peptides, antibodies, or small ligands, and small protein domains, such as HER-2 affibodies, have been applied to achieve targeting. To enhance the sensitivity of the contrast agents, these targeting moieties are usually linked to high payload MRI contrast agents or MRI contrast agents with high relaxivities.

Biochemistry

Phytomining would in principle cause minimal environmental effects compared to mining. Phytomining could also remove low-grade heavy metals from mine waste.

Environmental Chemistry

A drugs distribution coefficient strongly affects how easily the drug can reach its intended target in the body, how strong an effect it will have once it reaches its target, and how long it will remain in the body in an active form. Hence, the log P of a molecule is one criterion used in decision-making by medicinal chemists in pre-clinical drug discovery, for example, in the assessment of druglikeness of drug candidates. Likewise, it is used to calculate lipophilic efficiency in evaluating the quality of research compounds, where the efficiency for a compound is defined as its potency, via measured values of pIC or pEC, minus its value of log P'.

Physical Chemistry

The preferential alignment is a criterion of an orientation of a molecule or atom. The preferential alignment can be related to the formation of the crystal structure of an amorphous structure. For a polymer material with liquid crystals, the liquid crystals are molecules shaped like rigid rods. Just as logs being floated down a river tend to travel parallel to the direction of the river, liquid crystals have a preferential alignment with each other. At high temperatures, this alignment is disrupted and the material is said to be in the isotropic state. At lower temperatures, the alignment will take place and the liquid crystals are said to be in the pneumatic state [Hoong.C.C].

Analytical Chemistry

Meta-selective C–H functionalization refers to the regioselective reaction of a substituted aromatic ring on the C–H bond meta to the substituent. Substituted aromatic ring is an important type of substructure in pharmaceuticals and industrial compounds. Thus, synthetic methods towards substituted aromatic rings are always of great interest to chemists. Traditionally, regioselectivity on the aromatic ring is achieved by the electronic effect of substituents. Taking the well-known Friedel–Craft electrophilic aromatic substitution as example, electron donating groups direct the electrophile to ortho-/para-position while electron withdrawing groups direct the electrophile to meta-position. However, with complicated systems, electronic difference between different C–H bonds can be subtle and electronic directing effect alone could become less synthetically useful. The fast development of C–H activation in the past few decades provides synthetic chemists with the powerful tools to synthesize functionalized aromatic compounds with high selectivity. The widely used approach to achieve ortho-selectivity involves metal-chelating directing groups, which forms a relatively stable 6- or 7-membered cyclic pre-transition state to bring the metal catalyst to the proximity of the ortho-hydrogen. However, applying the same strategy to meta- or para- C-H functionalization does not work because the corresponding cyclophane-like cyclic pre-transition state is highly strained. Thus, while ortho-selectivity has been achieved by numerous catalytic systems, meta- and para-selectivity remains a challenge. In recent years, new strategies that override the electronic and steric bias have been developed to address meta-C–H functionalization. However, before these discoveries, synthesis of meta-substituted aromatic compounds could be either limited or cumbersome. For example, before the development of the C–H activation involving one-pot synthetic route to meta-substituted phenol derivatives by Maleczka and co-workers, the traditional synthesis requires 10 steps from TNT. Some early attempts utilize steric and electronic effects to achieve meta-selectivity. However, they are either limited to certain structure of substrates or are not highly selective. In recent years, several highly selective meta-C-H functionalization strategies have been reported which can override the intrinsic electronic and steric properties of the substrates and can apply to a wide range of substrate derivatives. The development of the modern meta-C-H functionalization strategies “open doors for numerous possibilities” for synthesis and catalyst development.

Organic Chemistry

The effluent from the tailings from the mining of sulfidic minerals has been described as "the largest environmental liability of the mining industry". These tailings contain large amounts of pyrite (FeS) and Iron(II) sulfide (FeS), which are rejected from the sought-after ores of copper and nickel, as well as coal. Although harmless underground, these minerals are reactive toward air in the presence of microorganisms, which if not properly managed lead to acid mine drainage.

Metallurgy

Chloromethane is an abundant organohalogen, anthropogenic or natural, in the atmosphere. Natural sources produce an estimated 4,100,000,000 kg/yr.

Environmental Chemistry

Coral is a calcifying organism, putting it at high risk for decay and slow growth rates as ocean acidification increases. Aragonite assists the coral as they build their skeletons because it is another form of calcium carbonate (CaCO) that is more soluble. When the pH of the water decreases, aragonite decreases as well, leading to the loss of calcium carbonate uptake in corals. Levels of aragonite have decreased by 16% since industrialization and could be lower in some portions of the Great Barrier Reef due to the current, which allows northern corals to take up more aragonite than southern corals. Aragonite is predicted to reduce by 0.1 by 2100 which could greatly hinder coral growth. Since 1990, calcification rates of Porites, a common large reef-building coral in the Great Barrier Reef, have decreased by 14.2% annually. Aragonite levels across the Great Barrier Reef itself are not equal; due to currents and circulation, some portions of the Great Barrier Reef can have half as much aragonite as others. Levels of aragonite are also affected by calcification and production, which can vary from reef to reef.If atmospheric carbon dioxide reaches 560 ppm, most ocean surface waters will be adversely undersaturated with respect to aragonite, and the pH will have reduced by about 0.24 units, from almost 8.2 today to just over 7.9. At this point (sometime in the third quarter of this century, at current rates of carbon dioxide increase), only a few parts of the Pacific will have levels of aragonite saturation adequate for coral growth. Additionally, if atmospheric carbon dioxide reaches 800 ppm, the ocean surface water pH decrease will be 0.4 units, and the total dissolved carbonate ion concentration will have decreased by at least 60%. Recent estimates state that with business-as-usual emission levels, the atmospheric carbon dioxide could reach 800 ppm by the year 2100. At this point, it is almost certain that all the reefs in the world will be in erosional states. Increasing the pH and replicating pre-industrialization ocean chemistry conditions in the Great Barrier Reef, however, led to an increase in coral growth rates of 7%.

Geochemistry

The National Oceanic Atmospheric Admiration in the United States has created a forecasting tool for regions such as the Great Lakes.

Environmental Chemistry

Stakeholder Program on Agent Detection Assays (SPADA) brings together expert stakeholders from the biothreat community to foster a comprehensive and uniform approach to scientific analysis and detection of biothreat agents.

Analytical Chemistry

The global steel industry has been going through major changes since 1970. China has emerged as a major producer and consumer, as has India to a lesser extent. Consolidation has been rapid in Europe. According to the 2019 International Energy Agency (IEA) report, the iron and steel industry directly contributed 2.6 Gt to global CO emissions and accounted for 7% of global energy demand. Singapore is the worlds main trading hub for iron, with about 90% of the worlds iron ore derivatives traded on their stock exchange.

Metallurgy

Usually, transition metal NHC complexes are prepared less directly. A popular method entails transmetallation of silver-NHC complexes. Such reagents are generated by the reaction of silver(I) oxide with the imidazolium salt.

Organic Chemistry

Expanded nucleotides and their oligomeric helices share many properties with their natural B-DNA counterparts, including their pairing preference: A with T, C with G. The various differences in chemical properties between xDNA and B-DNA support the hypothesis that the benzene ring which expands x-nucleobases is not, in fact, chemically inert. xDNA is more hydrophobic than B-DNA, and also has a smaller HOMO-LUMO gap (distance between the highest occupied molecular orbital and lowest unoccupied molecular orbital) as a result of modified saturation. xDNA has higher melting temperatures than B-DNA (a mixed decamer of xA and T has a melting temperature of 55.6 °C, 34.3 °C higher than the same decamer of A and T), and exhibits an "all-or-nothing" melting behaviour.

Biochemistry

Sublimation is historically used as a generic term to describe a two-step phase transition ― a solid-to-gas transition (sublimation in a more precise definition) followed by a gas-to-solid transition (deposition). (See below)

Analytical Chemistry

Oligosaprobes are organisms that inhabit clean water or water that is only slightly polluted by organic matter. Oxidation processes predominate in such waters owing to an excess of dissolved oxygen. Nitrates are among the nitrogen compounds present; there is little carbonic acid and no hydrogen sulfide. Oligosaprobic environments are aquatic environments rich in dissolved oxygen and (relatively) free from decayed organic matter.

Geochemistry

The regulation of gene expression in eukaryotes is achieved through the interaction of several levels of control that acts both locally to turn on or off individual genes in response to a specific cellular need and globally to maintain a chromatin-wide gene expression pattern that shapes cell identity. Because eukaryotic genome is wrapped around histones to form nucleosomes and higher-order chromatin structures, the substrates for transcriptional machinery are in general partially concealed. Without regulatory proteins, many genes are expressed at low level or not expressed at all. Transcription requires displacement of the positioned nucleosomes to enable the transcriptional machinery to gain access of the DNA. All steps in the transcription are subject to some degree of regulation. Transcription initiation in particular is the primary level at which gene expression is regulated. Targeting the rate-limiting initial step is the most efficient in terms of energy costs for the cell. Transcription initiation is regulated by cis-acting elements (enhancers, silencers, isolators) within the regulatory regions of the DNA, and sequence-specific trans-acting factors that act as activators or repressors. Gene transcription can also be regulated post-initiation by targeting the movement of the elongating polymerase.

Biochemistry

For each component in a binary mixture, one could make a vapor–liquid equilibrium diagram. Such a diagram would graph liquid mole fraction on a horizontal axis and vapor mole fraction on a vertical axis. In such VLE diagrams, liquid mole fractions for components 1 and 2 can be represented as and respectively, and vapor mole fractions of the corresponding components are commonly represented as and . Similarly for binary mixtures in these VLE diagrams: : and Such VLE diagrams are square with a diagonal line running from the () corner to the () corner for reference. These types of VLE diagrams are used in the McCabe–Thiele method to determine the number of equilibrium stages (or theoretical plates) needed to distill a given composition binary feed mixture into one distillate fraction and one bottoms fraction. Corrections can also be made to take into account the incomplete efficiency of each tray in a distillation column when compared to a theoretical plate.

Physical Chemistry

Following the first publication, Pockels' studies of surface films accelerated. She continued to correspond with Lord Rayleigh. These communications emphasized her findings concerning the importance of purity and cleanliness of the equipment, including a recognition of difficulties in her own experimentation regarding previously unrecognized contamination. Pockels pointed out that even airborne dust can affect results with her experimental apparatus. She recognized that impurities can affect reproducibility of experimental findings. Pockels developed a refined method of assessing monolayer films consisting of deposition of the compound on interest as a solution in benzene on the water surface in her sliding trough. Through this line of experimentation, she measured the thickness of certain monolayer films as being 13Å. With the aid of Lord Rayleigh, Pockelss second publication appeared in the journal Nature' in 1892. Pockels described the calming effect that oils can have on bodies of water, an effect first investigated in the published literature by Benjamin Franklin. Her research extended to investigations of other surface phenomena including capillarity and contact angles. Pockels published 14 scientific papers, mostly in German journals, the last one being published in 1926. She was eventually recognized as a pioneer in the emerging field of surface science. Following the death of her brother, Friedrich Carl Alwin Pockels in 1913 and her own ill health, Agnes Pockels lost contact with many professional scientists and ceased original research. Pockels never received a formal appointment for her scientific endeavors. Nevertheless, she published a number of scholarly papers and eventually received recognition as a pioneer in the new field of surface science. Commentators wrote: "When Langmuir received the Nobel Prize for Chemistry in 1932, for his work in investigating monolayers on solids and on liquids, part of his achievement was [...] founded on original experiments first made with a button and a thin tray, by a young lady of 18 who had had no formal scientific training."

Physical Chemistry

Allylic strain (also known as A strain, 1,3-allylic strain, or A-strain) in organic chemistry is a type of strain energy resulting from the interaction between a substituent on one end of an olefin (a synonym for an alkene) with an allylic substituent on the other end. If the substituents (R and R') are large enough in size, they can sterically interfere with each other such that one conformer is greatly favored over the other. Allylic strain was first recognized in the literature in 1965 by Johnson and Malhotra. The authors were investigating cyclohexane conformations including endocyclic and exocylic double bonds when they noticed certain conformations were disfavored due to the geometry constraints caused by the double bond. Organic chemists capitalize on the rigidity resulting from allylic strain for use in asymmetric reactions.

Stereochemistry

It is generally believed that the mechanical and other properties of the crystal are also pertinent to the subject matter, and that crystal morphology provides the missing link between growth kinetics and physical properties. The necessary thermodynamic apparatus was provided by Josiah Willard Gibbs study of heterogeneous equilibrium. He provided a clear definition of surface energy, by which the concept of surface tension is made applicable to solids as well as liquids. He also appreciated that an anisotropic surface free energy implied a non-spherical equilibrium shape, which should be thermodynamically defined as the shape which minimizes the total surface free energy'. It may be instructional to note that whisker growth provides the link between the mechanical phenomenon of high strength in whiskers and the various growth mechanisms which are responsible for their fibrous morphologies. (Prior to the discovery of carbon nanotubes, single-crystal whiskers had the highest tensile strength of any materials known). Some mechanisms produce defect-free whiskers, while others may have single screw dislocations along the main axis of growth—producing high strength whiskers. The mechanism behind whisker growth is not well understood, but seems to be encouraged by compressive mechanical stresses including mechanically induced stresses, stresses induced by diffusion of different elements, and thermally induced stresses. Metal whiskers differ from metallic dendrites in several respects. Dendrites are fern-shaped like the branches of a tree, and grow across the surface of the metal. In contrast, whiskers are fibrous and project at a right angle to the surface of growth, or substrate.

Analytical Chemistry

Employment of scavenger resins has become increasingly popular in solution-phase combinatorial chemistry. Used primarily in the synthesis of medicinal drugs, solution-phase combinatorial chemistry allows for the creation of large libraries of structurally related compounds. When purifying a solution, many approaches can be taken. In general chemical synthesis laboratories, a number of traditional techniques for purification are used as opposed to the employment of scavenger resins. Whether or not scavenger resins are used often depends on the quantity of product desired, how much time you have to produce the wanted product, and the use of the product. Some of the advantages and disadvantages to using scavenger resins as a means for purification are described later. Traditional methods of purification of these compounds becomes time consuming and does not always produce entirely pure products. The ability to specialize a scavenger resin allows for significantly reduce purification times and more pure products. Furthermore, the use of scavenger resins creates a situation where the product can remain in solution and the reaction can be monitored. Conversely, many scavenger resins must be used in large amounts to purify a given product, presenting physical purification issues. Furthermore, when discussing the use of scavenger resins it is important to think about the different types of solid support "beads" that will hold the selected functional group. These polymer beads can be describe most often in two ways, lightly crosslinked and highly crosslinked. The different solid supports are chosen at the preference of the chemist.

Organic Chemistry

In thermodynamics, an activity coefficient is a factor used to account for deviation of a mixture of chemical substances from ideal behaviour. In an ideal mixture, the microscopic interactions between each pair of chemical species are the same (or macroscopically equivalent, the enthalpy change of solution and volume variation in mixing is zero) and, as a result, properties of the mixtures can be expressed directly in terms of simple concentrations or partial pressures of the substances present e.g. Raoults law. Deviations from ideality are accommodated by modifying the concentration by an activity coefficient'. Analogously, expressions involving gases can be adjusted for non-ideality by scaling partial pressures by a fugacity coefficient. The concept of activity coefficient is closely linked to that of activity in chemistry.

Physical Chemistry

Lipotoxicity affects the pancreas when excess free fatty acids are found in beta cells, causing their dysfunction and death. The effects of the lipotoxicity is treated with leptin therapy and insulin sensitizers.

Biochemistry

Chain-growth polymerization (AE) or chain-growth polymerisation (BE) is a polymerization technique where unsaturated monomer molecules add onto the active site on a growing polymer chain one at a time. There are a limited number of these active sites at any moment during the polymerization which gives this method its key characteristics. Chain-growth polymerization involves 3 types of reactions : # Initiation: An active species I* is formed by some decomposition of an initiator molecule I # Propagation: The initiator fragment reacts with a monomer M to begin the conversion to the polymer; the center of activity is retained in the adduct. Monomers continue to add in the same way until polymers P* are formed with the degree of polymerization i # Termination: By some reaction generally involving two polymers containing active centers, the growth center is deactivated, resulting in dead polymer

Physical Chemistry

Very recently scalable all-perovskite based PEC photoelectrochemical system as solar hydrogen panel has been developed with >123 cm2 area.

Photochemistry

A protein skimmer or foam fractionator is a device used to remove organic compounds such as food and waste particles from water. It is most commonly used in commercial applications like municipal water treatment facilities, public aquariums, and aquaculture facilities. Smaller protein skimmers are also used for filtration of home saltwater aquariums and even freshwater aquariums and ponds.

Analytical Chemistry

GC content is found to be variable with different organisms, the process of which is envisaged to be contributed to by variation in selection, mutational bias, and biased recombination-associated DNA repair. The average GC-content in human genomes ranges from 35% to 60% across 100-Kb fragments, with a mean of 41%. The GC-content of Yeast (Saccharomyces cerevisiae) is 38%, and that of another common model organism, thale cress (Arabidopsis thaliana), is 36%. Because of the nature of the genetic code, it is virtually impossible for an organism to have a genome with a GC-content approaching either 0% or 100%. However, a species with an extremely low GC-content is Plasmodium falciparum (GC% = ~20%), and it is usually common to refer to such examples as being AT-rich instead of GC-poor. Several mammalian species (e.g., shrew, microbat, tenrec, rabbit) have independently undergone a marked increase in the GC-content of their genes. These GC-content changes are correlated with species life-history traits (e.g., body mass or longevity) and genome size, and might be linked to a molecular phenomenon called the GC-biased gene conversion.

Biochemistry

Excimer lamps are quasimonochromatic light sources operating over a wide range of wavelengths in the ultraviolet (UV) and vacuum ultraviolet (VUV) spectral regions. Operation of an excimer lamp is based on the formation of excited dimers (excimers), which spontaneously transiting from the excited state to the ground state result in the emission of UV photons. The spectral maximum of excimer lamp radiation is specified by a working excimer molecule: Excimers are diatomic molecules (dimers) or polyatomic molecules that have stable excited electronic states and an unbound or weakly bound (thermally unstable) ground state. Initially, only homonuclear diatomic molecules with a stable excited state but a repulsive ground state were called excimers (excited dimers). The term "excimer" was later extended to refer any polyatomic molecule with a repulsive or weakly bound ground state. One can also come across the term "exciplex" (from "excited complex"). It is also an excimer molecule but not a homonuclear dimer. For instance, Xe*, Kr*, Ar* are excimer molecules, while XeCl*, KrCl*, XeBr*, ArCl*, XeCl* are referred to exciplex molecules. Dimers of rare gases and rare-gas–halogen dimers are the most spread and studied excimers. Rare-gas–halide trimers, metal excimers, metal–rare-gas excimers, metal–halide excimers, and rare-gas–oxide excimers are also known, but they are rarely used. An excimer molecule can exist in an excited electronic state for a limited time, as a rule from a few to a few tens of nanoseconds. After that, an excimer molecule transits to the ground electronic state, while releasing the energy of internal electronic excitation in the form of a photon. Owing to a specific electronic structure of an excimer molecule, the energy gap between the lowest bound excited electronic state and the ground state amounts from 3.5 to 10 eV, depending on a kind of an excimer molecule and provides light emission in the UV and VUV spectral region. A typical spectral characteristic of excimer lamp radiation consists mainly of one intense narrow emission band. About 70–80% of the whole radiation power of an excimer lamp is concentrated in this emission band. The full width at half maximum of the emission band depends on a kind of an excimer molecule and excitation conditions and ranges within 2 to 15 nm. In fact, excimer lamps are sources of quasimonochromatic light. Therefore, such sources are suitable for spectral-selective irradiation and can even replace lasers in some cases.

Photochemistry

The JAK-STAT signaling pathway is instrumental in the development of limbs, specifically in its ability to regulate bone growth through paracrine signaling of cytokines. However, mutations in this pathway have been implicated in severe forms of dwarfism: thanatophoric dysplasia (lethal) and achondroplasic dwarfism (viable). This is due to a mutation in a Fgf gene, causing a premature and constitutive activation of the Stat1 transcription factor. Chondrocyte cell division is prematurely terminated, resulting in lethal dwarfism. Rib and limb bone growth plate cells are not transcribed. Thus, the inability of the rib cage to expand prevents the newborn's breathing.

Biochemistry

This salt is used as a flotation agent in the purification of molybdenite (MoS) from other components of the ores, where it is usually known as "Nokes reagent" (after Charles M. Nokes, who patented it in 1948). The salt is generated by the reaction of phosphorus pentasulfide with sodium hydroxide, often using impure reagents to obtain a mixture of the desired salt and related thiophosphates and oxidized species. Molybdenite particles, which are normally hydrophobic, become hydrophilic in the presence of this salt. In this context, the Nokes reagent is called a "depressant," because it suppresses the flotation tendency of the solids other than molybdenite.

Metallurgy

Tetrakis(hydroxymethyl)phosphonium chloride has industrial importance in the production of crease-resistant and flame-retardant finishes on cotton textiles and other cellulosic fabrics. A flame-retardant finish can be prepared from THPC by the Proban Process, in which THPC is treated with urea. The urea condenses with the hydroxymethyl groups on THPC. The phosphonium structure is converted to phosphine oxide as the result of this reaction.

Organic Chemistry

The carbonate-silicate cycle is the primary control on carbon dioxide levels over long timescales. It can be seen as a branch of the carbon cycle, which also includes the organic carbon cycle, in which biological processes convert carbon dioxide and water into organic matter and oxygen via photosynthesis.

Geochemistry

The prolemuris (Syaksyuk in Navi) are blue, hexapodal creatures based on Earths lemurs. They have two eyes, small nostrils, and their two upper arms on each side are partially fused. Like most Pandoran creatures, they have a queue on the back of their heads. They have lateral skin membranes on each side of the body. They have large eyes and grow 1.5 meters tall.

Biochemistry

Extractive metallurgy is a branch of metallurgical engineering wherein process and methods of extraction of metals from their natural mineral deposits are studied. The field is a materials science, covering all aspects of the types of ore, washing, concentration, separation, chemical processes and extraction of pure metal and their alloying to suit various applications, sometimes for direct use as a finished product, but more often in a form that requires further working to achieve the given properties to suit the applications. The field of ferrous and non-ferrous extractive metallurgy have specialties that are generically grouped into the categories of mineral processing, hydrometallurgy, pyrometallurgy, and electrometallurgy based on the process adopted to extract the metal. Several processes are used for extraction of the same metal depending on occurrence and chemical requirements.

Metallurgy

Prescriptions of thalidomide are accompanied by strict measures to avoid any risk of pregnancy. In the United States, the prescribing doctor is required to ensure that contraception is being used, and that regular pregnancy tests are taken.

Stereochemistry

*Isaaks, Edward H., and Srivastava, R. Mohan. An Introduction to Applied Geostatistics. Oxford University Press, Oxford, NY, USA, 1989. *David, M., Handbook of Applied Advanced Geostatistical Ore Reserve Estimation. Elsevier, Amsterdam, 1988. *Mineral Processing Plant Design, Practice, and Control - Proceedings. Ed. Mular, A., Halbe, D., and Barratt, D. Society for Mining, Metallurgy, and Exploration, Inc. 2002. *Mineral Comminution Circuits - Their Operation and Optimisation. Ed. Napier-Munn, T.J., Morrell, S., Morrison, R.D., and Kojovic, T. JKMRC, The University of Queensland, 1996

Metallurgy

Hydrofluorocarbons are included in the Kyoto Protocol and are regulated under the Kigali Amendment to the Montreal Protocol due to their very high Global Warming Potential and the recognition of halocarbon contributions to climate change. On September 21, 2007, approximately 200 countries agreed to accelerate the elimination of hydrochlorofluorocarbons entirely by 2020 in a United Nations-sponsored Montreal summit. Developing nations were given until 2030. Many nations, such as the United States and China, who had previously resisted such efforts, agreed with the accelerated phase out schedule. India successfully phased out HCFCs by 2020.

Environmental Chemistry

In chemistry, biochemistry and environmental sciences, deuterium is used as a non-radioactive, stable isotopic tracer, for example, in the doubly labeled water test. In chemical reactions and metabolic pathways, deuterium behaves somewhat similarly to ordinary hydrogen (with a few chemical differences, as noted). It can be distinguished from ordinary hydrogen most easily by its mass, using mass spectrometry or infrared spectrometry. Deuterium can be detected by femtosecond infrared spectroscopy, since the mass difference drastically affects the frequency of molecular vibrations; deuterium-carbon bond vibrations are found in spectral regions free of other signals. Measurements of small variations in the natural abundances of deuterium, along with those of the stable heavy oxygen isotopes O and O, are of importance in hydrology, to trace the geographic origin of Earth's waters. The heavy isotopes of hydrogen and oxygen in rainwater (so-called meteoric water) are enriched as a function of the environmental temperature of the region in which the precipitation falls (and thus enrichment is related to mean latitude). The relative enrichment of the heavy isotopes in rainwater (as referenced to mean ocean water), when plotted against temperature falls predictably along a line called the global meteoric water line (GMWL). This plot allows samples of precipitation-originated water to be identified along with general information about the climate in which it originated. Evaporative and other processes in bodies of water, and also ground water processes, also differentially alter the ratios of heavy hydrogen and oxygen isotopes in fresh and salt waters, in characteristic and often regionally distinctive ways. The ratio of concentration of H to H is usually indicated with a delta as δH and the geographic patterns of these values are plotted in maps termed as isoscapes. Stable isotopes are incorporated into plants and animals and an analysis of the ratios in a migrant bird or insect can help suggest a rough guide to their origins.

Geochemistry

A quinone methide is a type of conjugated organic compound that contain a cyclohexadiene with a carbonyl and an exocyclic methylidene or extended alkene unit. It is analogous to a quinone, but having one of the double bonded oxygens replaced with a carbon. The carbonyl and methylidene are usually oriented either ortho or para to each other. There are some examples of transient synthetic meta quinone methides.

Organic Chemistry

Various bioinformatics tools can be used to analyze end-sequence profiling. Common ones include BreakDancer, PEMer, Variation Hunter, common LAW, GASV, and Spanner. ESP can be used to map structural variation at high-resolution in disease tissue. This technique is mainly used on tumor samples from different cancer types. Accurate identification of copy neutral chromosomal abnormalities is particularly important as translocation can lead to fusion proteins, chimeric proteins, or misregulated proteins that can be seen in tumors. This technique can also be used in evolution studies by identifying large structural variation between different populations. Similar methods are being developed for various applications. For example, a barcoded Illumina paired-end sequencing (BIPES) approach was used to assess microbial diversity by sequencing the 16S V6 tag.

Biochemistry

The degradation of organic matter through respiration in the modern ocean is facilitated by different electron acceptors, their favorability based on Gibbs free energy law, and the laws of thermodynamics. This redox chemistry is the basis for life in deep sea sediments and determines the obtainability of energy to organisms that live there. From the water interface moving toward deeper sediments, the order of these acceptors is oxygen, nitrate, manganese, iron, and sulfate. The zonation of these favored acceptors can be seen in Figure 1. Moving downwards from the surface through the zonation of these deep ocean sediments, acceptors are used and depleted. Once depleted the next acceptor of lower favorability takes its place. Thermodynamically, oxygen represents the most favorable electron accepted but is quickly used up in the water sediment interface and concentrations extends only millimeters to centimeters down into the sediment in most locations of the deep sea. This favorability indicates an organism's ability to obtain higher energy from the reaction which helps them compete with other organisms. In the absence of these acceptors, organic matter can also be degraded through methanogenesis, but the net oxidation of this organic matter is not fully represented by this process. Each pathway and the stoichiometry of its reaction are listed in table 1. Due to this quick depletion of in the surface sediments, a majority of microbes use anaerobic pathways to metabolize other oxides such as manganese, iron, and sulfate. It is also important to figure in bioturbation and the constant mixing of this material which can change the relative importance of each respiration pathway. For the microbial perspective please reference the electron transport chain.

Geochemistry

Induction heating is a non contact heating process which uses the principle of electromagnetism induction to produce heat in a work-piece. In this case thermal expansion is used in a mechanical application to fit parts over one another, e.g. a bushing can be fitted over a shaft by making its inner diameter slightly smaller than the diameter of the shaft, then heating it until it fits over the shaft, and allowing it to cool after it has been pushed over the shaft, thus achieving a shrink fit. By placing a conductive material into a strong alternating magnetic field, electric current can be made to flow in the metal thereby creating heat due to the IR losses in the material. The current generated flows predominantly in the surface layer. The depth of this layer being dictated by the frequency of the alternating field and the permeability of the material. Induction heaters for shrink fitting fall into two broad categories: * Mains frequency (MF) units using magnetic cores (iron) * Solid state MF and radio frequency (RF) heaters

Metallurgy

Human immunodeficiency virus is a viral infection that targets the lymph nodes. HIV binds to the immune CD4 cell and reverse transcriptase alters the host cell genome to allow integration of the viral DNA via integrase. The virus replicates using the host cell's machinery and then leaves the cell to infect additional cells via budding.

Biochemistry

Oscar Paul Kuipers (Rotterdam, May 12, 1956) is a Dutch professor of molecular genetics at the University of Groningen. His areas of expertise include microbiology, biochemistry, molecular and cell biology, and biotechnology.

Organic Chemistry

Fluorescence spectroscopy (also known as fluorimetry or spectrofluorometry) is a type of electromagnetic spectroscopy that analyzes fluorescence from a sample. It involves using a beam of light, usually ultraviolet light, that excites the electrons in molecules of certain compounds and causes them to emit light; typically, but not necessarily, visible light. A complementary technique is absorption spectroscopy. In the special case of single molecule fluorescence spectroscopy, intensity fluctuations from the emitted light are measured from either single fluorophores, or pairs of fluorophores. Devices that measure fluorescence are called fluorometers.

Physical Chemistry

Most experimentally determined values of the thermal contact resistance fall between 0.000005 and 0.0005 m K/W (the corresponding range of thermal contact conductance is 200,000 to 2000 W/m K). To know whether the thermal contact resistance is significant or not, magnitudes of the thermal resistances of the layers are compared with typical values of thermal contact resistance. Thermal contact resistance is significant and may dominate for good heat conductors such as metals but can be neglected for poor heat conductors such as insulators. Thermal contact conductance is an important factor in a variety of applications, largely because many physical systems contain a mechanical combination of two materials. Some of the fields where contact conductance is of importance are: * Electronics ** Electronic packaging ** Heat sinks ** Brackets * Industry ** Nuclear reactor cooling ** Gas turbine cooling ** Internal combustion engines ** Heat exchangers ** Thermal insulation ** Press hardening of automotive steels * Flight ** Hypersonic flight vehicles ** Thermal supervision for space vehicles * Residential/building science ** Performance of building envelopes

Physical Chemistry

Nitrifying bacteria are chemolithotrophic organisms that include species of genera such as Nitrosomonas, Nitrosococcus, Nitrobacter, Nitrospina, Nitrospira and Nitrococcus. These bacteria get their energy from the oxidation of inorganic nitrogen compounds. Types include ammonia-oxidizing bacteria (AOB) and nitrite-oxidizing bacteria (NOB). Many species of nitrifying bacteria have complex internal membrane systems that are the location for key enzymes in nitrification: ammonia monooxygenase (which oxidizes ammonia to hydroxylamine), hydroxylamine oxidoreductase (which oxidizes hydroxylamine to nitric oxide - which is further oxidized to nitrite by a currently unidentified enzyme), and nitrite oxidoreductase (which oxidizes nitrite to nitrate).

Biochemistry

Zinc was extracted in India as early as in the 4th to 3rd century BCE. Zinc production may have begun in India, and ancient northwestern India is the earliest known civilization that produced zinc on an industrial scale. The distillation technique was developed around 1200 CE at Zawar in Rajasthan. In the 17th century, China exported Zinc to Europe under the name of totamu or tutenag. The term tutenag may derive from the South Indian term Tutthanagaa (zinc). In 1597, Libavius, a metallurgist in England received some quantity of Zinc metal and named it as Indian/Malabar lead. In 1738, William Champion is credited with patenting in Britain a process to extract zinc from calamine in a smelter, a technology that bore a strong resemblance to and was probably inspired by the process used in the Zawar zinc mines in Rajasthan. His first patent was rejected by the patent court on grounds of plagiarising the technology common in India. However, he was granted the patent on his second submission of patent approval. Postlewayts Universal Dictionary of 1751 still wasnt aware of how Zinc was produced. The Arthashastra describes the production of zinc. The Rasaratnakara by Nagarjuna describes the production of brass and zinc. There are references of medicinal uses of zinc in the Charaka Samhita (300 BCE). The Rasaratna Samuchaya (800 CE) explains the existence of two types of ores for zinc metal, one of which is ideal for metal extraction while the other is used for medicinal purpose. It also describes two methods of zinc distillation.

Metallurgy

A yeast two-hybrid screening (Y2H) tests a "bait" protein against many potential interacting proteins ("prey") to identify physical protein–protein interactions. This system is based on a transcription factor, originally GAL4, whose separate DNA-binding and transcription activation domains are both required in order for the protein to cause transcription of a reporter gene. In a Y2H screen, the "bait" protein is fused to the binding domain of GAL4, and a library of potential "prey" (interacting) proteins is recombinantly expressed in a vector with the activation domain. In vivo interaction of bait and prey proteins in a yeast cell brings the activation and binding domains of GAL4 close enough together to result in expression of a reporter gene. It is also possible to systematically test a library of bait proteins against a library of prey proteins to identify all possible interactions in a cell.

Biochemistry

Two widely employed applications of migratory insertion of carbonyl groups are hydroformylation and the production of acetic acid by carbonylation of methanol. The former converts alkenes, hydrogen, and carbon monoxide into aldehydes. The production of acetic acid by carbonylation proceeds via two similar industrial processes. More traditional is the Monsanto acetic acid process, which relies on a rhodium-iodine catalyst to transform methanol into acetic acid. This process has been superseded by the Cativa process which uses a related iridium catalyst, [Ir(CO)I] (1). By 2002, worldwide annual production of acetic acid stood at 6 million tons, of which approximately 60% is produced by the Cativa process. The Cativa process catalytic cycle, shown above, includes both insertion and de-insertion steps. The oxidative addition reaction of methyl iodide with (1) involves the formal insertion of the iridium(I) centre into the carbon-iodine bond, whilst step (3) to (4) is an example of migratory insertion of carbon monoxide into the iridium-carbon bond. The active catalyst species is regenerated by the reductive elimination of acetyl iodide from (4), a de-insertion reaction.

Organic Chemistry

In interfacial shear rheology, the interfacial area remains the same throughout the measurement. Instead, the interfacial area is sheared in order to be able to measure the surface stress present. The equations are similar to dilatational interfacial rheology but shear modulus is often marked with G instead of E like in dilational methods. In a general case, G and E are not equal. Since interfacial rheological properties are relatively weak, it causes challenges for the measurement equipment. For high sensitivity, it is essential to maximize the contribution of the interface while minimizing the contribution of the bulk phase. The Boussinesq number, Bo, depicts how sensitive a measurement method is for detecting the interfacial viscoelasticity. The commercialized measurement techniques for interfacial shear rheology include magnetic needle method, rotating ring method and rotating bicone method. The magnetic needle method, developed by Brooks et al., has the highest Boussinesq number of the commercialized methods. In this method, a thin magnetic needle is oscillated at the interface using a magnetic field. By following the movement of the needle with a camera, the viscoelastic properties of the interface can be detected. This method is often used in combination with a Langmuir trough in order to be able to conduct the experiment as a function of the packing density of the molecules or particles.

Physical Chemistry

The concept of gene therapy is to fix a genetic problem at its source. If, for instance, a mutation in a certain gene causes the production of a dysfunctional protein resulting (usually recessively) in an inherited disease, gene therapy could be used to deliver a copy of this gene that does not contain the deleterious mutation and thereby produces a functional protein. This strategy is referred to as gene replacement therapy and could be employed to treat inherited retinal diseases. While the concept of gene replacement therapy is mostly suitable for recessive diseases, novel strategies have been suggested that are capable of also treating conditions with a dominant pattern of inheritance. * The introduction of CRISPR gene editing has opened new doors for its application and utilization in gene therapy, as instead of pure replacement of a gene, it enables correction of the particular genetic defect. Solutions to medical hurdles, such as the eradication of latent human immunodeficiency virus (HIV) reservoirs and correction of the mutation that causes sickle cell disease, may be available as a therapeutic option in the future. * Prosthetic gene therapy aims to enable cells of the body to take over functions they physiologically do not carry out. One example is the so-called vision restoration gene therapy, that aims to restore vision in patients with end-stage retinal diseases. In end-stage retinal diseases, the photoreceptors, as the primary light sensitive cells of the retina are irreversibly lost. By the means of prosthetic gene therapy light sensitive proteins are delivered into the remaining cells of the retina, to render them light sensitive and thereby enable them to signal visual information towards the brain. In vivo, gene editing systems using CRISPR have been used in studies with mice to treat cancer and have been effective at reducing tumors. In vitro, the CRISPR system has been used to treat HPV cancer tumors. Adeno-associated virus, Lentivirus based vectors have been to introduce the genome for the CRISPR system.

Biochemistry

ERH has been used for over 15 years for treatment of unconsolidated soils in both the vadose and saturated zones. Recent advancements and results show that ERH can be an effective treatment method for bedrock. At an ERH site, the primary electrical current path is on the thin layer of water immediately adjacent to the soil or rock grains. Little current is carried by the water in the pore volume. It is not the pore fluid that dominates the electrical conductivity; it is the grain wetting fluid that dominates the electrical conductivity. Sedimentary rock will typically possess the thin layer of water required for current flow. This means ERH can effectively be used for treatment of sedimentary bedrock, which typically has significant primary porosity.

Environmental Chemistry

Strong evidence of metallurgical activities has been revealed in levels 9 to 6, dating to the Ubaid period, and especially in level 7 (4166 +/- 170 cal BC). Hearths or natural draft furnaces, slag, ore, and pigment had been recovered throughout the site. This was in the context of architectural complexes typical of southern Mesopotamian architecture. Unusually, the metallurgical activities at the site appear to have been limited to the melting and casting of copper objects. Arsenical copper objects were clearly manufactured on site, yet the technological aspects of this productions remain unclear. This is because the primary smelting of ore seems to have been undertaken elsewhere, perhaps already at the mining sites. So questions remain as to whether or not arsenic was already present in the ores, or added later. In contrast, the related Norşuntepe site provides a better context of production, and demonstrates that some form of arsenic alloying was indeed taking place by the 4th millennium BC. Since the slag identified at Norşuntepe contains no arsenic, this means that arsenic was added separately.

Metallurgy

Non-linear inverse Compton scattering (NICS), also known as non-linear Compton scattering and multiphoton Compton scattering, is the scattering of multiple low-energy photons, given by an intense electromagnetic field, in a high-energy photon (X-ray or gamma ray) during the interaction with a charged particle, in many cases an electron. This process is an inverted variant of Compton scattering since, contrary to it, the charged particle transfers its energy to the outgoing high-energy photon instead of receiving energy from an incoming high-energy photon. Furthermore, differently from Compton scattering, this process is explicitly non-linear because the conditions for multiphoton absorption by the charged particle are reached in the presence of a very intense electromagnetic field, for example, the one produced by high-intensity lasers. Non-linear inverse Compton scattering is a scattering process belonging to the category of light-matter interaction phenomena. The absorption of multiple photons of the electromagnetic field by the charged particle causes the consequent emission of an X-ray or a gamma ray with energy comparable or higher with respect to the charged particle rest energy. The normalized vector potential helps to isolate the regime in which non-linear inverse Compton scattering occurs ( is the electron charge, is the electron mass, <math>c the vector potential). If , the emission phenomenon can be reduced to the scattering of a single photon by an electron, which is the case of inverse Compton scattering. While, if , NICS occurs and the probability amplitudes of emission have non-linear dependencies on the field. For this reason, in the description of non-linear inverse Compton scattering, is called classical non-linearity parameter.

Physical Chemistry

An "ion-channel forming" molecule can often show multiple types of conductance activities in planar bilayer membranes. Each of these modes of action can be characterized by their * open duration (sub-ms---hours), related to whether the active structure is kinetically labile, * unit conductance (pS---nS), related to the geometry of the active structure, and * open probability, a fraction related to the thermodynamic stability of that active structure relative to inactive forms. These events are not necessarily uniform throughout their durations, and as a result a variety of shapes of conducting traces are possible.

Supramolecular Chemistry

Transposons and retrotransposons are mobile genetic elements. Retrotransposon repeated sequences, which include long interspersed nuclear elements (LINEs) and short interspersed nuclear elements (SINEs), account for a large proportion of the genomic sequences in many species. Alu sequences, classified as a short interspersed nuclear element, are the most abundant mobile elements in the human genome. Some examples have been found of SINEs exerting transcriptional control of some protein-encoding genes. Endogenous retrovirus sequences are the product of reverse transcription of retrovirus genomes into the genomes of germ cells. Mutation within these retro-transcribed sequences can inactivate the viral genome. Over 8% of the human genome is made up of (mostly decayed) endogenous retrovirus sequences, as part of the over 42% fraction that is recognizably derived of retrotransposons, while another 3% can be identified to be the remains of DNA transposons. Much of the remaining half of the genome that is currently without an explained origin is expected to have found its origin in transposable elements that were active so long ago (> 200 million years) that random mutations have rendered them unrecognizable. Genome size variation in at least two kinds of plants is mostly the result of retrotransposon sequences.

Biochemistry

Quantitative chemical analysis is a key part of environmental chemistry, since it provides the data that frame most environmental studies. Common analytical techniques used for quantitative determinations in environmental chemistry include classical wet chemistry, such as gravimetric, titrimetric and electrochemical methods. More sophisticated approaches are used in the determination of trace metals and organic compounds. Metals are commonly measured by atomic spectroscopy and mass spectrometry: Atomic Absorption Spectrophotometry (AAS) and Inductively Coupled Plasma Atomic Emission (ICP-AES) or Inductively Coupled Plasma Mass Spectrometric (ICP-MS) techniques. Organic compounds, including PAHs, are commonly measured also using mass spectrometric methods, such as Gas chromatography-mass spectrometry (GC/MS) and Liquid chromatography-mass spectrometry (LC/MS). Tandem Mass spectrometry MS/MS and High Resolution/Accurate Mass spectrometry HR/AM offer sub part per trillion detection. Non-MS methods using GCs and LCs having universal or specific detectors are still staples in the arsenal of available analytical tools. Other parameters often measured in environmental chemistry are radiochemicals. These are pollutants which emit radioactive materials, such as alpha and beta particles, posing danger to human health and the environment. Particle counters and Scintillation counters are most commonly used for these measurements. Bioassays and immunoassays are utilized for toxicity evaluations of chemical effects on various organisms. Polymerase Chain Reaction PCR is able to identify species of bacteria and other organisms through specific DNA and RNA gene isolation and amplification and is showing promise as a valuable technique for identifying environmental microbial contamination.

Environmental Chemistry

*Porphyrins, and phthalocyanines have highly tunable photochemical and electrochemical activity as well as the potential to form complexes. *Photochromic and photoisomerizable groups can change their shapes and properties, including binding properties, upon exposure to light. *Tetrathiafulvalene (TTF) and quinones have multiple stable oxidation states, and therefore can be used in redox reactions and electrochemistry. *Other units, such as benzidine derivatives, viologens, and fullerenes, are useful in supramolecular electrochemical devices.

Supramolecular Chemistry

Ca ions are usually kept at nanomolar levels in the cytosol of plant cells, and act in a number of signal transduction pathways as second messengers.

Biochemistry

* 24 August 2007: A large buildup of sea foam occurred on the coast of Yamba, northern New South Wales. * January–February 2008: Sea foam occurrences at Caloundra and Point Cartwright on Queensland's Sunshine Coast attracted world-wide media attention. * December 2011: The coast road at Cleveleys, Lancashire was swamped by meter-high drifts of sea foam. * 2012: During live coverage of Hurricane Irene in Ocean City, Maryland, Tucker Barnes was covered in sea foam. * 24–25 September 2012: Following storms and high winds, the beach front of the Footdee area of Aberdeen was engulfed with sea foam. * 27–28 January 2013: The Sunshine Coast in Queensland, Australia had masses of foam wash up on land from ex-tropical cyclone Oswald. * June 2016: Sea foam occurred across the East coast of Australia, whipped up by storms. * 28 March 2017: Sea foam was generated by Cyclone Debbie at Sarina Beach in Queensland, Australia. * 16 October 2017: Hurricane Ophelia covered Cleveleys, Lancashire with spume. * January 2018: Storm Eleanor causes widespread foam to appear across coastal Europe. * 11 October 2019: Subtropical storm Melissa brought sea foam to Nantasket Beach in Hull, Massachusetts. * 21 January 2020: Storm Gloria floods Tossa de Mar, Spain, with thick sea foam on top of major flooding. * 11 May 2020: Five surfers die in The Netherlands, presumably upon drowning after becoming disoriented in over 2 meters thick sea foam. * 13 July 2020: The Cape Town storm, South Africa

Geochemistry

There are four commonly used types of applications for nitinol: ; Free recovery : Nitinol is deformed at a low temperature, remains deformed, and then is heated to recover its original shape through the shape memory effect. ; Constrained recovery : Similar to free recovery, except that recovery is rigidly prevented and thus a stress is generated. ; Work production : The alloy is allowed to recover, but to do so it must act against a force (thus doing work). ; Superelasticity : Nitinol acts as a super spring through the superelastic effect. Superelastic materials undergo stress-induced transformation and are commonly recognized for their "shape-memory" property. Due to its superelasticity, NiTi wires exhibit "elastocaloric" effect, which is stress-triggered heating/cooling. NiTi wires are currently under research as the most promising material for the technology. The process begins with tensile loading on the wire, which causes fluid (within the wire) to flow to HHEX (hot heat exchanger). Simultaneously, heat will be expelled, which can be used to heat the surrounding. In the reverse process, tensile unloading of the wire leads to fluid flowing to CHEX (cold heat exchanger), causing the NiTi wire to absorb heat from the surrounding. Therefore, the temperature of the surrounding can be decreased (cooled). Elastocaloric devices are often compared with magnetocaloric devices as new methods of efficient heating/cooling. Elastocaloric device made with NiTi wires has an advantage over magnetocaloric device made with gadolinium due to its specific cooling power (at 2 Hz), which is 70X better (7 kWh/kg vs. 0.1 kWh/kg). However, elastocaloric device made with NiTi wires also have limitations, such as its short fatigue life and dependency on large tensile forces (energy consuming). In 1989 a survey was conducted in the United States and Canada that involved seven organizations. The survey focused on predicting the future technology, market, and applications of SMAs. The companies predicted the following uses of nitinol in a decreasing order of importance: (1) Couplings, (2) Biomedical and medical, (3) Toys, demonstration, novelty items, (4) Actuators, (5) Heat Engines, (6) Sensors, (7) Cryogenically activated die and bubble memory sockets, and finally (8) lifting devices.

Metallurgy

In the early 2000s, Zhao's group reported that visible light can accelerate the degradation of organic pollutants with aqueous solutions of iron tetrasulfophthalocyanine ([Fe(PcS)]) and Hydrogen peroxide|. They also found out FeBR (Fe complex of 2,2′-bipyridine) is efficient in eliminating organic pollutants such as rhodamine B (RhB), malachite green (MG) and N, N-dimethylaniline (DMA). They did several control experiments, in the dark or under irradiation, with or without irradiation. They proposed that when light is introduced, excitation of [Fe(PcS)] can result in electron transfer from ligand(L) to Fe, then Fe can be reduced to Fe. The Fe-L complex can react with to produce HO, leading to the degradation of pollutants.

Environmental Chemistry

Kendomycin is an anticancer macrolide first isolated from Streptomyces violaceoruber. It has potent activity as an endothelin receptor antagonist and anti-osteoporosis agent. It also has strong cytotoxicity against various tumor cell lines.

Organic Chemistry

Combining operando Raman, UV–Vis and ATR-IR is particularly useful for studying homogeneous catalysis in solution. Transition-metal complexes can perform catalytic oxidation reactions on organic molecules; however, much of the corresponding reaction pathways are still unclear. For example, an operando study of the oxidation of veratryl alcohol by salcomine catalyst at high pH determined that the initial oxidation of the two substrate molecules to aldehydes is followed by the reduction of molecular oxygen to water, and that the rate determining step is the detachment of the product. Understanding organometallic catalytic activity on organic molecules is incredibly valuable for the further development of material science and pharmaceuticals.

Physical Chemistry

Many forms of oxyhydrogen lamps have been described, such as the limelight, which used an oxyhydrogen flame to heat a piece of lime to white hot incandescence. Because of the explosiveness of the oxyhydrogen, limelights have been replaced by electric lighting.

Physical Chemistry

This method tries to identify 4-bp long end motifs from each stands 5 end on bisulfite sequencing reads of plasma cfDNAs. Hierarchical clustering of the motifs is done to detect any under/overrepresentation of these motifs due to cancer existence. The method incorporates Support Vector Machines and Logistic Regression to predict cancer patients from healthy ones. The method is also applied to transplant patients with clustering and multidimensional scaling (MDS) analysis and shows applicability. The same analysis types also proved that this method applies to prenetal testing. This method is also informative for cell type origins.

Biochemistry

Glycobiology is a monthly peer-reviewed scientific journal covering all aspects of the field of glycobiology and the official journal of the Society for Glycobiology. It is published by Oxford University Press. The journal was established in September 1990. It publishes primary research on the "biological functions of glycans, including glycoproteins, glycolipids, proteoglycans and free oligosaccharides, and on proteins that specifically interact with glycans."

Biochemistry

The δSi value of sediment porewater may be affected by post-depositional (diagenetic) precipitation or dissolution of Si. It is important to understand the extent and isotopic fractionations of these processes, as they alter the δSi values of the originally deposited sediments, and determine the δSi preserved in the rock record. Generally, precipitation of Si prefers the light isotope (Si) and leads to Si-enriched dissolved Si in the hosting solution. The isotopic effect of Si dissolution in porewater is yet to be clear, as some studies report a preference for Si during dissolution, while other studies document that isotopic fractionation was not expressed during dissolution of sediments.

Geochemistry

Pletz grouped the explosophores into eight distinct categories. ;I. :These represent: :* the nitro group, a nitrogen atom bound to two oxygen atoms as well as an organic molecule (e.g. TNT, RDX) :* the nitrate ion, a nitrogen atom bound to three oxygen atoms, (e.g. nitroglycerin, ANFO) :* the nitrite ion, a nitrogen atom bound to two oxygen atoms :Most commercially used explosives include the nitrate ion or the nitro group. ;II. :The azo and azide groups respectively, connected to organic/inorganic compounds (e.g. silver azide , lead azide , ammonium azide ) ;III. :The halogenated nitrogen group X:halogen (e.g. nitrogen triiodide and nitrogen trichloride ) ;IV. :The fulminate group (e.g. fulminic acid HONC and mercury fulminate ) ;V. :The chlorate and perchlorate groups respectively, connected to organics/inorganics (e.g. potassium chlorate , fluorine perchlorate ) ;VI. :The peroxide and ozonide groups respectively, connected to organics/inorganics (e.g. acetone peroxide, butanone peroxide) ;VII. :The acetylide group with its metal derivatives (e.g. silver acetylide , copper acetylide ) ;VIII. A metal atom connected by an unstable bond to the carbon of certain organic radicals :This class contains for instance organic compounds of mercury, thallium, and lead. ;Other :Other substances have been characterised as explosophores outside of the eight classes as defined by Pletz.

Organic Chemistry

Annonins are a group of chemical compounds classified as acetogenins. They are found in the extracts of Annona seeds (A. squamosa and A. muricata). Annonin-based bioinsecticides are used to control Coleoptera (beetle) pests commonly found in stored organic cereal and beans in the country of Brazil. Other different types of annonin-based insecticides, derived from A. mucosa, fight off lepidopteran (moth) pests that infest cabbage leaves, also found in the tropical climates of Brazil. The benefit of using these bioinsecticides is their relatively low cost and no phytotoxicity. These annonin molecules act as overpowering inhibitors of complex I (NADH: ubiquinone oxidoreductase) in the electron-transport chain in the mitochondria of quarry pests. In cell membranes of these same pests, annonins also inhibit coenzyme NADH, causing these arthropods to die.

Biochemistry

The Schikorr reaction formally describes the conversion of the iron(II) hydroxide (Fe(OH)) into iron(II,III) oxide (FeO). This transformation reaction was first studied by Gerhard Schikorr. The global reaction follows: It is of special interest in the context of the serpentinization, the formation of hydrogen by the action of water on a common mineral.

Metallurgy

Volatile phenolic compounds are found in plant resin where they may attract benefactors such as parasitoids or predators of the herbivores that attack the plant. In the kelp species Alaria marginata, phenolics act as chemical defence against herbivores. In tropical Sargassum and Turbinaria species that are often preferentially consumed by herbivorous fishes and echinoids, there is a relatively low level of phenolics and tannins. Marine allelochemicals generally are present in greater quantity and diversity in tropical than in temperate regions. Marine algal phenolics have been reported as an apparent exception to this biogeographic trend. High phenolic concentrations occur in brown algae species (orders Dictyotales and Fucales) from both temperate and tropical regions, indicating that latitude alone is not a reasonable predictor of plant phenolic concentrations.

Organic Chemistry

The scientific work of Leonidas Zervas had a global resonance and his contribution was recognised by multiple awards throughout his life. In 1960 he received an honorary doctorate from the University of Basel on the occasion of the university's 500th anniversary, upon recommendation of Hans Erlenmeyer and Nobel laureate Tadeusz Reichstein. In 1969 he was bestowed honorary membership of the American Society of Biological Chemists. In 1976 he was conferred the (1st class) by the Socialist Republic of Romania. In the same year Zervas was made Foreign Member of the USSR Academy of Sciences, an indication of the great respect for his work in the Eastern Block, too. The Max-Bergmann-Kreis company of German peptide chemists planned to present Zervas with the first Max Bergmann golden medal for peptide chemistry in 1980, but his sudden death necessitated a posthumous award ceremony. In honour of Zervas, a commemorative bust has been unveiled in his birthtown Megalopolis in 1991 and the main conference hall of the National Hellenic Research Foundation is called the "Leonidas Zervas amphitheatre". The European Peptide Society has established the Leonidas Zervas Award "in commemoration of his outstanding contributions to peptide science", awarded biennially since 1988. The award is given to the "scientist who has made the most outstanding contributions to the chemistry, biochemistry and/or biology of peptides in the five years preceding the date of selection".

Organic Chemistry

Tools and weapons, chisels and axe-heads, spearheads or dagger-blades, are the only surviving artifacts of the Copper Age, and do not show artistic treatment. But some Early Minoan pottery forms are plainly copied from metal prototypes, cups and jugs of simple construction and rather elaborate design. The cups are conical and sometimes a stem-foot; there are oval jars with long tubular spouts, and beaked jugs with round shoulders set on conical bodies. Heads of rivets which tie the metal parts together are often reproduced as a decorative element in clay. The spouted jars and pierced type of axe-head indicate that metallurgical connections of Early Minoan Crete were partly Mesopotamian.

Metallurgy

Museomics is the study of genomic data obtained from ancient DNA (aDNA) and historic DNA (hDNA) specimens in museum collections. Early research in this area focused on short sequences of DNA from mitochondrial genes, but sequencing of whole genomes has become possible. Next-generation sequencing (NGS) and high-throughput sequencing (HTS) methods can be applied to the analysis of genetic datasets extracted from collections materials. Such techniques have been described as a "third revolution in sequencing technology". Like radiocarbon dating, the techniques of museomics are a transformative technology. Results are revising and sometimes overturning previously accepted theories about a wide variety of topics such as the domestication of the horse. Museum collections contain unique resources such as natural history specimens, which can be used for genome-scale examinations of species, their evolution, and their responses to environmental change. Ancient DNA provides a unique window into genetic change over time. It enables scientists to directly study evolutionary and ecological processes, comparing ancient and modern populations, identifying distinct populations, and revealing patterns of change such as extinctions and migrations. Research may be used to identify isolated populations and inform conservation priorities. However, museum specimens can be poorly preserved and are subject to degradation and contamination. Genomic analyses face considerable challenges as a result of the highly degraded DNA typical of museum specimens. DNA from such samples is often subject to post-mortem nucleotide damage such as the hydrolytic deamination of cytosine (C) to uracil (U) residues. PCR amplification of damaged templates can further substitute uracils with thymine (T), completing a C to T substitution path. Such errors tend to occur towards the ends of molecules, accumulate with time, and can be significant in specimens a century-old or later. Robust genomic and statistical techniques are needed to rigorously detect and avoid errors and genotyping uncertainties when carrying out analyses based on museum collections. Optimal methods for working with hDNA and aDNA can differ as a result of differences in their DNA degradation history. Museomics also involves destructive sampling, irreversibly removing parts of sometimes rare specimens to obtain DNA. This can be contentious for curators and collection staff, involving a variety of ethical issues around the handling and destruction of objects, colonial acquisition and repatriation practices, and present-day social and political implications of research. Museums, universities and journals are increasingly developing ethics statements, best practices and guidelines for such work.

Analytical Chemistry

In stereochemistry, diastereomers (sometimes called diastereoisomers) are a type of stereoisomer. Diastereomers are defined as non-mirror image, non-identical stereoisomers. Hence, they occur when two or more stereoisomers of a compound have different configurations at one or more (but not all) of the equivalent (related) stereocenters and are not mirror images of each other. When two diastereoisomers differ from each other at only one stereocenter, they are epimers. Each stereocenter gives rise to two different configurations and thus typically increases the number of stereoisomers by a factor of two. Diastereomers differ from enantiomers in that the latter are pairs of stereoisomers that differ in all stereocenters and are therefore mirror images of one another. Enantiomers of a compound with more than one stereocenter are also diastereomers of the other stereoisomers of that compound that are not their mirror image (that is, excluding the opposing enantiomer). Diastereomers have different physical properties (unlike most aspects of enantiomers) and often different chemical reactivity. Diastereomers differ not only in physical properties but also in chemical reactivity — how a compound reacts with others. Glucose and galactose, for instance, are diastereomers. Even though they share the same molar weight, glucose is more stable than galactose. This difference in stability causes galactose to be absorbed slightly faster than glucose in human body. Diastereoselectivity is the preference for the formation of one or more than one diastereomer over the other in an organic reaction. In general, stereoselectivity is attributed to torsional and steric interactions in the stereocenter resulting from electrophiles approaching the stereocenter in reaction.

Stereochemistry

Ashing is a test to deduce the amount of ash forming material present in a petroleum product so as to decide its use in certain applications. Ash-forming materials are considered to be undesirable impurities or contaminants. In the ash analysis of petroleum products, ash content represents the incombustible component remaining after a sample of the furnace oil is completely burned. The ash content of petroleum products is generally low. It is defined as the inorganic residue that remains after combustion of the oil in air at specific high temperature. Ash typically ranges from 0.1 to 0.2% in oil. Some of the ash forming constituents occur naturally in crude oil; others are present as a result of refining or contamination during storage or distribution. Knowledge of the amount of ash-forming material present in a product can provide information as to whether or not the product is suitable application. In the ash analysis of coal and other solid fuels, the amount of sulfur retained in the ash during the ashing process is not constant, but rather is dependent upon the conditions of ashing as well as the other inorganic constituents in the ash that may form sulfates during the ashing procedure. As such, different ashing procedures may yield different ash contents.

Analytical Chemistry

Lipidology is the scientific study of lipids. Lipids are a group of biological macromolecules that have a multitude of functions in the body. Clinical studies on lipid metabolism in the body have led to developments in therapeutic lipidology for disorders such as cardiovascular disease.

Biochemistry