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In many research labs, the use of asbestos gloves is required when operating the furnace because it can reach very high temperatures. The use of face masks is also recommended at higher temperatures to ensure the safety of researchers and junior lab members. It is also recommended that researchers performing the LOI ... | 3 | Analytical Chemistry |
Photopolymers can be used to generate printing plates, which are then pressed onto paper-like metal type. This is often used in modern fine printing to achieve the effect of embossing (or the more subtly three-dimensional effect of letterpress printing) from designs created on a computer without needing to engrave desi... | 5 | Photochemistry |
* Orbifold signature:
* Coxeter notation: [∞,2,∞] or [∞,2,∞]
* Lattice: rhombic
* Point group: D
* The group cm contains no rotations. It has reflection axes, all parallel. There is at least one glide reflection whose axis is not a reflection axis; it is halfway between two adjacent parallel re... | 3 | Analytical Chemistry |
Macromolecular crystallography was preceded by the older field of small-molecule x-ray crystallography (for structures with less than a few hundred atoms). Small-molecule diffraction data extends to much higher resolution than feasible for macromolecules, and has a very clean mathematical relationship between the data ... | 1 | Biochemistry |
mTOR inhibitors may be useful for treating/preventing several age-associated conditions, including neurodegenerative diseases such as Alzheimers disease and Parkinsons disease. After a short-term treatment with the mTOR inhibitors dactolisib and everolimus, in elderly (65 and older), treated subjects had a reduced numb... | 1 | Biochemistry |
Prokaryotes use one type of RNA polymerase, transcribing mRNAs that code for more than one type of protein. Transcription, translation and mRNA degradation all happen simultaneously. Transcription termination is essential to define boundaries in transcriptional units, a function necessary to maintain the integrity of t... | 1 | Biochemistry |
The endocannabinoid system, broadly speaking, includes:
* The endogenous arachidonate-based lipids, anandamide (N-arachidonoylethanolamide) and 2-AG, besides other N-acylethanolamines (NAEs); these are known as "endocannabinoids" and are physiological ligands for the cannabinoid receptors. Endocannabinoids are all eic... | 1 | Biochemistry |
NAD kinase (EC 2.7.1.23, NADK) is an enzyme that converts nicotinamide adenine dinucleotide (NAD) into NADP through phosphorylating the NAD coenzyme. NADP is an essential coenzyme that is reduced to NADPH primarily by the pentose phosphate pathway to provide reducing power in biosynthetic processes such as fatty acid b... | 1 | Biochemistry |
The reactive enodiolate species is also sensitive to oxygen (O), which results in the dual carboxylase / oxygenase activity of RuBisCO. This reaction is considered wasteful as it produces products (3-phosphoglycerate and 2-phosphoglycolate) that must be catabolized through photorespiration. This process requires energy... | 7 | Physical Chemistry |
The microarray—the dense, two-dimensional grid of biosensors—is the critical component of a biochip platform. Typically, the sensors are deposited on a flat substrate, which may either be passive (e.g. silicon or glass) or active, the latter
consisting of integrated electronics or micromechanical devices th... | 1 | Biochemistry |
An alternative method used to create ATP is through oxidative phosphorylation, which takes place during cellular respiration. This process utilizes the oxidation of NADH to NAD, yielding 3 ATP, and of FADH to FAD, yielding 2 ATP. The potential energy stored as an electrochemical gradient of protons (H) across the inner... | 1 | Biochemistry |
A historic example of L1-conferred disease is Haemophilia A, which is caused by insertional mutagenesis. There are nearly 100 examples of known diseases caused by retroelement insertions, including some types of cancer and neurological disorders. Correlation between L1 mobilization and oncogenesis has been reported for... | 1 | Biochemistry |
Quantum dots (QDs) are nano-scale semiconductor particles on the order of 2–10 nm in diameter. They possess electrical properties between those of bulk semi-conductors and individual molecules, as well as optical characteristics that make them suitable for applications where fluorescence is desirable, such as medical i... | 7 | Physical Chemistry |
Since the neutron is not charged it does not interact via the Coulomb force and therefore does not ionize the scintillation material. It must first transfer some or all of its energy via the strong force to a charged atomic nucleus. The positively charged nucleus then produces ionization. Fast neutrons (generally >0.5 ... | 5 | Photochemistry |
Two discoveries led to the development of glycosynthase enzymes. The first was that a change of the active site nucleophile of a glycosidase from a carboxylate to another amino acid resulted in a properly folded protein that had no hydrolase activity.
The second discovery was that some glycosidase enzymes were able t... | 0 | Organic Chemistry |
Metabolites can be divided into two groups: those produced during the growth phase of the organism, called primary metabolites and those produced during the stationary phase, called secondary metabolites. Some examples of primary metabolites are ethanol, citric acid, glutamic acid, lysine, vitamins and polysaccharides.... | 1 | Biochemistry |
During his time at the University of Wisconsin, Stork kept a steak on his windowsill in the winter in order to keep it refrigerated. The steak began to degrade and to dispose of it Stork put it in a hot acid bath used to clean glassware which contained nitric and sulphuric acids. He was then concerned he would produce ... | 0 | Organic Chemistry |
Different polymer surfaces have different side chains on their monomers that can become charged due to the adsorption or dissociation of adsorbates. For example, polystyrene sulfonate has monomers containing negatively charged side chains which can adsorb positively charged adsorbates. Polystyrene sulfonate will adsorb... | 7 | Physical Chemistry |
The function of the HNMT enzyme is histamine metabolism by ways of N-methylation using S-adenosyl--methionine (SAM-e) as the methyl donor, producing N-methylhistamine, which, unless excreted, can be further processed by monoamine oxidase B (MAOB) or by diamine oxidase (DAO). Methylated histamine metabolites are excrete... | 1 | Biochemistry |
The calcium cycle is a transfer of calcium between dissolved and solid phases. There is a continuous supply of calcium ions into waterways from rocks, organisms, and soils. Calcium ions are consumed and removed from aqueous environments as they react to form insoluble structures such as calcium carbonate and calcium si... | 9 | Geochemistry |
In chemistry, dissociative substitution describes a reaction pathway by which compounds interchange ligands. The term is typically applied to coordination and organometallic complexes, but resembles the S1 mechanism in organic chemistry. This pathway can be well described by the cis effect, or the labilization of CO ... | 0 | Organic Chemistry |
Syntrophy, in the context of microbial metabolism, refers to the pairing of multiple species to achieve a chemical reaction that, on its own, would be energetically unfavorable. The best studied example of this process is the oxidation of fermentative end products (such as acetate, ethanol and butyrate) by organisms s... | 1 | Biochemistry |
Thermodynamic equilibrium is characterized by the free energy for the whole (closed) system being a minimum. For systems at constant temperature and pressure the Gibbs free energy is minimum. The slope of the reaction free energy with respect to the extent of reaction, ξ, is zero when the free energy is at its minimum ... | 7 | Physical Chemistry |
Olson remained at the Flory group for a post doc research, after which she became a Damon Runyon Cancer Research Foundation Postdoctoral Fellow with geneticist Charles R. Cantor at Columbia University.
In 1972, Olson became an assistant professor at Rutgers University and full professor in 1979.
During her time at Rutg... | 1 | Biochemistry |
In this case, both electrons and H ions are involved and the electrode potential is a function of pH. The reaction equation may be written:
Using the expressions for the free energy in terms of potentials, the energy balance is given by a Nernst equation:
For the iron and water example, considering the boundary line be... | 7 | Physical Chemistry |
# Using ATP as energy, citrate is broken down into the acetyl group and oxaloacetate.
# The acetyl group joins the coenzyme in the cytosol, forming acetyl-CoA. | 1 | Biochemistry |
One of the zilches has been rediscovered. This is the zilch known as "optical chirality". This name was given by Tang and Cohen since this zilch determines the degree of chiral asymmetry in the rate of excitation of a small chiral molecule by an incident electromagnetic field.
A further physical insight of optical chir... | 4 | Stereochemistry |
During the Dark Ages of the transition from bronze to iron, the decorative arts stood almost still but industrial metalwork was freely produced. There are a few remains of Geometric bronze vessels, but as in the case of the Early Minoan material, metal forms are recorded in their pottery derivatives. Some vase-shapes a... | 8 | Metallurgy |
Off-targeting is another challenge to the use of siRNAs as a gene knockdown tool. Here, genes with incomplete complementarity are inadvertently downregulated by the siRNA (in effect, the siRNA acts as a miRNA), leading to problems in data interpretation and potential toxicity. This, however, can be partly addressed by ... | 1 | Biochemistry |
* For burner fuel, Concarbon provides an approximation of the tendency of the fuel to form deposits in vaporizing pot-type and sleeve-type burners.
* For diesel fuel, Concarbon correlates approximately with combustion chamber deposits, provided that alkyl nitrates are absent, or if present, that the test is performed o... | 9 | Geochemistry |
Selecting an oocyte for in vitro fertilization involves assessing the quality of the oocyte which is usually done by accessing the morphological features of the oocyte. The major parts of the oocyte that are accessed for quality in terms of morphological characteristics are the cumulus cells, zona pellucida, polar body... | 1 | Biochemistry |
In the highly versatile and widely used Evans’ Aldol Reaction, allylic strain played a major role in the development of the reaction. The Z enolate was created to avoid the allylic strain with oxazolidinone. The formation of a specific enolate enforces the development of relative stereochemistry throughout the reaction... | 4 | Stereochemistry |
The measured full SPR curves (x-axis: angle, y-axis: reflected light intensity) can be transcribed into sensograms (x-axis: time, y-axis: selected parameter such as peak minimum, light intensity, peak width). The sensograms can be fitted using binding models to obtain kinetic parameters including on- and off-rates and ... | 7 | Physical Chemistry |
The history of ferrous metallurgy in the Indian subcontinent began in the 2nd millennium BC. Archaeological sites in Gangetic plains have yielded iron implements dated between 1800 and 1200 BC. By the early 13th century BC, iron smelting was practiced on a large scale in India. In Southern India (present day Mysore) ir... | 8 | Metallurgy |
Multiplex ligation-dependent probe amplification was invented by Jan Schouten, a Dutch scientist. The method was first described in 2002 in the scientific journal Nucleic Acid Research. The first applications included the detection of exon deletions in the human genes BRCA1, MSH2 and MLH1, which are linked to heredita... | 1 | Biochemistry |
The matte, which is produced in the smelter, contains 30–70% copper (depending on the process used and the operating philosophy of the smelter), primarily as copper sulfide, as well as iron sulfide. The sulfur is removed at a high temperature as sulfur dioxide by blowing air through molten matte:
:2 CuS + 3 O → 2 CuO +... | 8 | Metallurgy |
A well studied pioneer factor family is the Groucho-related (Gro/TLE/Grg) transcription factors that often have a negative effect on transcription. These chromatin binding domains can span up to 3-4 nucleosomes. These large domains are scaffolds for further protein interactions and also modify the chromatin for other... | 1 | Biochemistry |
The history of metallurgy in the Urals stands out to historians and economists as a separate stage in the history of Russian industry and covers the period from the 4th millennium BC to the present day. The emergence of the mining district is connected with the history of Ural metallurgy. The geography of the Ural meta... | 8 | Metallurgy |
Professor David Knowles FREng FIMMM (born 6 January 1967) is Professor of Nuclear Engineering at the University of Bristol and Chief Executive of the UK's Henry Royce Institute for advanced materials research. From 2016 to 2019, he was the co-director of the South West Nuclear Hub, and Atkins Fellow. His work focusses ... | 8 | Metallurgy |
It is very rare for activity coefficient values to have been determined experimentally for a system at equilibrium. There are three options for dealing with the situation where activity coefficient values are not known from experimental measurements.
#Use calculated activity coefficients, together with concentrations o... | 7 | Physical Chemistry |
Lithium enolates, one of the precursors to silyl enol ethers, can also be generated from silyl enol ethers using methyllithium. The reaction occurs via nucleophilic substitution at the silicon of the silyl enol ether, producing the lithium enolate and tetramethylsilane. | 0 | Organic Chemistry |
In thermodynamics, the excess chemical potential is defined as the difference between the chemical potential of a given species and that of an ideal gas under the same conditions (in particular, at the same pressure, temperature, and composition).
The chemical potential of a particle species is therefore given by an i... | 7 | Physical Chemistry |
The Ycf4 protein domain found on the thylakoid membrane is vital to photosystem I. This thylakoid transmembrane protein helps assemble the components of photosystem I. Without it, photosynthesis would be inefficient. | 5 | Photochemistry |
RNA silencing describes several mechanistically related pathways which are involved in controlling and regulating gene expression. RNA silencing pathways are associated with the regulatory activity of small non-coding RNAs (approximately 20–30 nucleotides in length) that function as factors involved in inactivating hom... | 1 | Biochemistry |
The cycle's importance is based on preventing lactic acidosis during anaerobic conditions in the muscle. However, normally, before this happens, the lactic acid is moved out of the muscles and into the liver.
Additionally, this cycle is important in ATP production, an energy source, during muscle exertion. The end of m... | 1 | Biochemistry |
Synaptic transmission can be changed by previous activity. These changes are called synaptic plasticity and may result in either a decrease in the efficacy of the synapse, called depression, or an increase in efficacy, called potentiation. These changes can either be long-term or short-term. Forms of short-term plasti... | 1 | Biochemistry |
Serotonylation is the process by which serotonin effects the exocytosis of alpha-granules from platelets (also known as thrombocytes). This involves the serotonylation of small GTPases such as Rab4 and RhoA. It has been suggested that "further understanding of the specific hormonal role of 5-HT in hemostasis and thromb... | 1 | Biochemistry |
TALEN can be used to edit genomes by inducing double-strand breaks (DSB), which cells respond to with repair mechanisms.
Non-homologous end joining (NHEJ) directly ligates DNA from either side of a double-strand break where there is very little or no sequence overlap for annealing. This repair mechanism induces errors ... | 1 | Biochemistry |
For clarification, a distinction between the two corresponding cases is needed. With reference to a phase diagram, the sublimation that occurs left of the solid-gas boundary, the triple point or the solid-liquid boundary (corresponding to evaporation in vaporization) may be called gradual sublimation; and the substance... | 3 | Analytical Chemistry |
Much of the early understanding of transcription came from bacteria, although the extent and complexity of transcriptional regulation is greater in eukaryotes. Bacterial transcription is governed by three main sequence elements:
* Promoters are elements of DNA that may bind RNA polymerase and other proteins for the suc... | 1 | Biochemistry |
Often, modification of the structure will take place around the glycosidic linkage. Replacement of one or other of the glycosidic oxygen atoms by carbon, sulfur, nitrogen etc. will alter the properties of the glycosidic bond. The molecules produced in this way would be called carbasugars or C-glycosides, thiosugars or ... | 1 | Biochemistry |
Monoaminergic cell groups refers to collections of neurons in the central nervous system that have been demonstrated by histochemical fluorescence to contain one of the neurotransmitters serotonin, dopamine, norepinephrine or epinephrine. Thus, it represents the combination of catecholaminergic cell groups and serotone... | 1 | Biochemistry |
An inert gas (or noble gas), such as helium, is one that does not react with other elements or compounds. Adding an inert gas into a gas-phase equilibrium at constant volume does not result in a shift. This is because the addition of a non-reactive gas does not change the equilibrium equation, as the inert gas appears... | 7 | Physical Chemistry |
Crystal optics is the branch of optics that describes the behaviour of light in anisotropic media, that is, media (such as crystals) in which light behaves differently depending on which direction the light is propagating. The index of refraction depends on both composition and crystal structure and can be calculated u... | 3 | Analytical Chemistry |
Particulate inorganic carbon (PIC) usually takes the form of calcium carbonate (CaCO), and plays a key part in the ocean carbon cycle. This biologically fixed carbon is used as a protective coating for many planktonic species (coccolithophores, foraminifera) as well as larger marine organisms (mollusk shells). Calcium ... | 9 | Geochemistry |
Beryllium halides are formed by a combination of halogen with a beryllium atom. Beryllium halides are mostly covalent in nature except for the fluoride which is more ionic. They can be used as Lewis acid catalysts. Preparation for these compounds varies by the halogen. Beryllium halides are among the most common starti... | 0 | Organic Chemistry |
A total synthesis of progesterone was reported in 1971 by W.S. Johnson. The synthesis begins with reacting the phosphonium salt with phenyl lithium to produce the phosphonium ylide . The ylide is reacted with an aldehyde to produce the alkene . The ketal protecting groups of are hydrolyzed to produce the diketone , ... | 0 | Organic Chemistry |
Metal-organic frameworks are crystalline porous polymers assembled from organic monomers connected by coordination to metal atom centers. | 6 | Supramolecular Chemistry |
Despite having only four choices for each monomer unit (nucleotides), compared to 20 amino acid side chains found in proteins, ribozymes have diverse structures and mechanisms. In many cases they are able to mimic the mechanism used by their protein counterparts. For example, in self cleaving ribozyme RNAs, an in-line ... | 7 | Physical Chemistry |
The corrosive effects of nitric acid are exploited for some specialty applications, such as etching in printmaking, pickling stainless steel or cleaning silicon wafers in electronics.
A solution of nitric acid, water and alcohol, nital, is used for etching metals to reveal the microstructure. ISO 14104 is one of the st... | 3 | Analytical Chemistry |
An arrastra (or arastra) is a primitive mill for grinding and pulverizing (typically) gold or silver ore. Its simplest form is two or more flat-bottomed drag stones placed in a circular pit paved with flat stones, and connected to a center post by a long arm. With a horse, mule or human providing power at the other end... | 8 | Metallurgy |
The E. coli strain W3110 was genetically engineered to generate 2 moles of acetate for every 1 mole of glucose that undergoes fermentation. This is known as a homoacetate pathway. | 1 | Biochemistry |
Systemic agmatine can potentiate opioid analgesia and prevent tolerance to chronic morphine in laboratory rodents. Since then, cumulative evidence amply shows that agmatine inhibits opioid dependence and relapse in several animal species. | 1 | Biochemistry |
The type II receptors phosphorylate the type I receptors; the type I receptors are then enabled to phosphorylate cytoplasmic R-Smads, which then act as transcriptional regulators. Signaling is initiated by the binding of TGF-β to its serine/threonine receptors. The serene/threonine receptors are the type II and type I ... | 1 | Biochemistry |
Most domains have a very broad substrate specificity and usually only the A-domain determines which amino acid is incorporated in a module. Ten amino acids that control substrate specificity and can be considered the codons of nonribosomal peptide synthesis have been identified, and rational protein design has yielded ... | 1 | Biochemistry |
Silica gel is a chemically inert, non-toxic, polar and dimensionally stable (. It is prepared by the reaction between sodium silicate and acetic acid, which is followed by a series of after-treatment processes such as aging, pickling, etc. These after-treatment methods results in various pore size distributions.
Silica... | 7 | Physical Chemistry |
Sodium trifluoromethanesulfinate (CFSONa) as a trifluoromethylation reagent was introduced by Langlois in 1991. The reaction requires t-butyl hydroperoxide and generally a metal and proceeds through a radical mechanism. The reagent has been applied with heterocyclic substrates | 0 | Organic Chemistry |
In 1814, Jean-Jacques Colin discovered (to his surprise) that a mixture of dry gaseous ammonia and iodine formed a shiny, metallic-appearing liquid. Frederick Guthrie established the precise composition of the resulting I···NH complex fifty years later, but the physical processes underlying the molecular interaction re... | 6 | Supramolecular Chemistry |
*Kefir
**In Kefir, the lactose in milk is fermented by lactic acid bacteria to produce lactic acid, further breakdown to propionic acid is done by propionibacteria. Yeast in Kefir ferment to produce ethanol, which is consumed by other bacteria to make acids and aldehydes that contribute to flavor.
* Sake
** In the ... | 1 | Biochemistry |
The site was opened in 1931 by the Lindsay Light and Chemical Company. It processed ores like monazite to produce elements, including thorium and uranium. It also made gaslight mantles, and during World War II, hydrofluoric acid.
In 1958, it became owned by American Potash and Chemical Company (AMPOT), which at one poi... | 8 | Metallurgy |
Saturation conditions can be viewed as a special case of pre-equilibrium conditions. At the concentration of substrate examined, formation of the catalyst-substrate complex is rapid and essentially irreversible. The catalyst resting state consists entirely of the bound complex, and [A] is no longer present in the rate ... | 7 | Physical Chemistry |
Binding of a number of hormones and steroids, including testosterone, progesterone, and cholesterol, has been found to occur with sigma-2 receptors, though in some cases with lower affinity than to the sigma-1 receptor. Signaling caused by this binding is thought to occur via a calcium secondary messenger and calcium-d... | 1 | Biochemistry |
As for aldehydes, the hydrogen atoms on the carbon adjacent ("α to") the carboxyl group in esters are sufficiently acidic to undergo deprotonation, which in turn leads to a variety of useful reactions. Deprotonation requires relatively strong bases, such as alkoxides. Deprotonation gives a nucleophilic enolate, which c... | 0 | Organic Chemistry |
Fusion of a cyclooctyne to two aryl rings increases the reaction rate, and the cyclooctyne reagents of the Bertozzi group proceeded through a series of fusions that sought to increase the ring strain even further. DIBO (dibenzo cyclooctyne) was developed as a precursor to BARAC (biarylazacyclooctynone), although calcul... | 0 | Organic Chemistry |
The Flory–Stockmayer Theory predicts the gel point for the system consisting of three types of monomer units
:linear units with two A-groups (concentration ),
:linear units with two B groups (concentration ),
:branched A units (concentration ).
The following definitions are used to formally define the system
The theo... | 7 | Physical Chemistry |
Perhaps the single most important reaction of enolate ions is their alkylation by treatment with an alkyl halide or tosylate, thereby forming a new C-C bond and joining two smaller pieces into one larger molecule. Alkylation occurs when the nucleophilic enolate ion reacts with the electrophilic alkyl halide in an SN re... | 0 | Organic Chemistry |
Propionyl chloride (also propanoyl chloride) is the organic compound with the formula CHCHC(O)Cl. It is the acyl chloride derivative of propionic acid. It undergoes the characteristic reactions of acyl chlorides. It is a colorless, corrosive, volatile liquid.
It is used as a reagent for organic synthesis. In derived ... | 0 | Organic Chemistry |
A study of four distinct hydrolases (human serum paraoxonase (PON1), pseudomonad phosphotriesterase (PTE), Protein tyrosine phospatase(PTP) and human carbonic anhydrase II (CAII)) has shown the main activity is "robust" towards change, whereas the promiscuous activities are weak and more "plastic". Specifically, select... | 1 | Biochemistry |
A suitable setup for automated thermometric titrimetry comprises the following:
* Precision fluid dispensing devices – "burettes" – for adding titrants and dosing of other reagents
* Thermistor-based thermometric sensor
* Titration vessel
* Stirring device, capable of highly efficient stirring of vessel contents withou... | 3 | Analytical Chemistry |
The Brinkman number (Br) is a dimensionless number related to heat conduction from a wall to a flowing viscous fluid, commonly used in polymer processing. It is named after the Dutch mathematician and physicist Henri Brinkman. There are several definitions; one is
where
* μ is the dynamic viscosity;
* u is the flow ve... | 7 | Physical Chemistry |
The Gill Mantle ("Txampaysye" in Navi) is a large jellyfish like creature native to Pandoras reefs. The Navi can bond with them in the water, which can supply them with oxygen through the water allowing Navi to remain underwater much longer. They are primarily used by Kiri throughout Avatar: The Way of Water. | 1 | Biochemistry |
Iodosobenzene has no commercial uses, but in the laboratory it is employed as an "oxo-transfer reagent." It epoxidizes certain alkenes and converts some metal complexes into the corresponding oxo derivatives. Although it is an oxidant, it is also mildly nucleophilic. These oxo-transfer reactions operate by the intermed... | 0 | Organic Chemistry |
Catalysts based on synthetic metalloporphyrins have been extensively investigated, although few or no applications exist. Due to their distinctive redox properties, Co(II)–porphyrin-based systems are radical initiators. Some complexes emulate the action of various heme enzymes such as cytochrome P450, lignin peroxidase... | 1 | Biochemistry |
In the tables of quantities and their units, the ISO 31-8 standard shows symbols for substances as subscripts (e.g., c, w, p). It also notes that it is generally advisable to put symbols for substances and their states in parentheses on the same line, as in c(HSO). | 7 | Physical Chemistry |
An amphibolic pathway is one that can be either catabolic or anabolic based on the availability of or the need for energy. The currency of energy in a biological cell is adenosine triphosphate (ATP), which stores its energy in the phosphoanhydride bonds. The energy is utilized to conduct biosynthesis, facilitate moveme... | 1 | Biochemistry |
* 1912: Nobel Prize in Chemistry for his discovery of the Grignard reagent (shared the award with fellow Frenchman Paul Sabatier).
* 1912: Lavoisier Medal, Société Chimique de France
* 1933: Légion d'Honneur, Commander | 0 | Organic Chemistry |
is a dense, colourless liquid, although crude samples may be yellow or even red-brown. It is one of the rare transition metal halides that is a liquid at room temperature, vanadium tetrachloride| being another example. This property reflects the fact that molecules of weakly self-associate. Most metal chlorides are po... | 0 | Organic Chemistry |
The iron–sulfur world hypothesis is a set of proposals for the origin of life and the early evolution of life advanced in a series of articles between 1988 and 1992 by Günter Wächtershäuser, a Munich patent lawyer with a degree in chemistry, who had been encouraged and supported by philosopher Karl R. Popper to publish... | 1 | Biochemistry |
In 1978 the United States banned the use of CFCs such as Freon in aerosol cans, the beginning of a long series of regulatory actions against their use. The critical DuPont manufacturing patent for Freon ("Process for Fluorinating Halohydrocarbons", U.S. Patent #3258500) was set to expire in 1979. In conjunction with ot... | 2 | Environmental Chemistry |
The introduction of atom into a crystal of atom creates a pinning point for multiple reasons. An alloying atom is by nature a point defect, thus it must create a stress field when placed into a foreign crystallographic position, which could block the passage of a dislocation. However, it is possible that the alloying m... | 8 | Metallurgy |
In mass spectroscopy based proteomics there are three major steps needed for peptide identification: sample preparation, separation of peptides, and identification of peptides. Several groups have focused on oocytes or very early cleavage-stage cells since these cells are unusually large and provide enough material for... | 1 | Biochemistry |
Catalysts that promote chain walking were discovered in the 1980-1990s. Nickel(II) and palladium(II) complexes of α-diimine ligands were known to efficiently catalyze polymerization of alkenes. They are also referred as Brookhart's catalysts after being used for making of high molar mass polyolefins for the first time... | 7 | Physical Chemistry |
As series resistance increases, the voltage drop between the junction voltage and the terminal voltage becomes greater for the same current. The result is that the current-controlled portion of the I-V curve begins to sag toward the origin, producing a significant decrease in the terminal voltage V and a slight reducti... | 7 | Physical Chemistry |
Nanocars are a new class of molecular machines that can roll across solid surfaces with structurally defined direction. They are molecules essentially composed of a few tens or hundreds of hydrogen and carbon atoms and are measuring one to three nanometers.
The nanocar is propelled step by step by electrical impulses a... | 6 | Supramolecular Chemistry |
In organic chemistry, anti-periplanar, or antiperiplanar, describes the bond angle in a molecule. In this conformer, the dihedral angle of the bond and the bond is greater than +150° or less than −150° (Figures 1 and ). Anti-periplanar is often used in textbooks to mean strictly anti-coplanar, with an dihedral ang... | 0 | Organic Chemistry |
The essence of Brønsted–Lowry theory is that an acid is only such in relation to a base, and vice versa. Water is amphoteric as it can act as an acid or as a base. In the image shown at the right one molecule of acts as a base and gains to become while the other acts as an acid and loses to become .
Another example... | 7 | Physical Chemistry |
In March 1865 Macadam sailed to New Zealand to give evidence at the trial of Captain W. A. Jarvey, accused of fatally poisoning his wife, but the jury did not reach a verdict. During the return voyage, Macadam fractured his ribs during a storm. He was advised, on medical grounds, not to return for the adjourned trial b... | 3 | Analytical Chemistry |
* The first TEs were discovered in maize (Zea mays) by Barbara McClintock in 1948, for which she was later awarded a Nobel Prize. She noticed chromosomal insertions, deletions, and translocations caused by these elements. These changes in the genome could, for example, lead to a change in the color of corn kernels. Abo... | 1 | Biochemistry |
The usual definition of a splash zone is the area just above and just below the average water level of a body of water. It also includes areas that may be subject to water spray and mist.
A significant amount of corrosion of fences is due to landscaper tools scratching fence coatings and irrigation sprinklers spraying ... | 8 | Metallurgy |
The second law of thermodynamics can be interpreted as quantifying state transformations which are statistically unlikely so that they become effectively forbidden. The second law typically applies to systems composed of many particles interacting; Quantum thermodynamics resource theory is a formulation of thermodynami... | 7 | Physical Chemistry |
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