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*Nobel Prize in Physics, with Marie Curie and Henri Becquerel (1903)
*Davy Medal, with Marie Curie (1903)
*Matteucci Medal, with Marie Curie (1904)
*Elliott Cresson Medal (1909) awarded posthumously during Marie Curie's award ceremony
* Citation for Chemical Breakthrough Award from the Division of History of Chemistry of the American Chemical Society (2015) | 1 | Applied and Interdisciplinary Chemistry |
Assay sensitivity for a non-inferiority trial may depend upon the chosen margin of inferiority ruled out by the trial, and the design of the planned non-inferiority trial. The chosen margin of inferiority in a non-inferiority trial cannot be larger than the largest effect size which the control intervention reliably and reproducibly demonstrates compared to placebo or no treatment in past superiority trials. For instance, if there is reliable and reproducible evidence from previous superiority trials of an effect size of 10% for a control intervention compared to placebo, an appropriately designed non-inferiority trial designed to rule out that the test intervention may be as much as 5% less effective than the control would have assay sensitivity. On the other hand, with this same data, a noninferiority trial designed to rule out that the test intervention may be as much as 15% less effective than the control may not have assay sensitivity, since this trial would not ensure that the test intervention is any more effective than a placebo given that the effect ruled out is larger than the effect of the control compared to placebo. The choice of the margin is sometimes problematic in non-inferiority trials. Given investigators desire to choose larger margins to decrease the sample size needed to perform a trial, the chosen margin is sometimes larger than the effect size of the control compared to placebo. In addition, a valid noninferiority trial is not possible in situations in which there is a lack of data demonstrating a reliable and reproducible effect of the control compared to placebo.
In addition to choosing a margin based upon credible past evidence, to have assay sensitivity, the planned non-inferiority trial must be designed in a way similar to the past trials which demonstrated the effectiveness of the control compared to placebo, the so-called "constancy assumption". In this way, non-inferiority trials have a feature in common with external (historically) controlled trials. This also means that non-inferiority trials are subject to some of the same biases as historically controlled trials; that is, the effect of a drug in a past trial may not be the same in a current trial given changes in medical practice, differences in disease definitions or changes in the natural history of a disease, differences in outcome timing and definitions, usage of concomitant medications, etc.
The finding of "difference" or "no difference" between two interventions is not a direct demonstration of the internal validity of the trial unless another internal control confirms that the study methods have the ability to show a difference, if one exists, over the range of interest (i.e. the trial contains a third group receiving placebo). Since most clinical trials do not contain an internal "negative" control (i.e. a placebo group) to internally validate the trial, the data to evaluate the validity of the trial comes from past trials external to the current trial. | 1 | Applied and Interdisciplinary Chemistry |
After he went to Germany from Estonia in 1941 he began his studies of chemistry in 1949 at the University of Tübingen until 1951. He became Dr. rer. nat. in 1954 at the Ludwig Maximilian University of Munich. He did his habilitation 1960 at the same university. After a short but very successful career in industry at Bayer from 1962 until 1968 when he joined the University of Southern California at Los Angeles.
From 1971 he worked at the Technical University of Munich, and was an emeritus from 1999 until his death in 2005. | 0 | Theoretical and Fundamental Chemistry |
In the ideal regime, the usual ideal-gas behavior is qualitatively recovered. For an ideal gas, in fact, the value of the fundamental derivative reduces to the constant value , where is the heat capacity ratio. By definition, is the ratio between the constant pressure and the constant volume specific heats, so it is larger than 1, leading to a value of larger than 1 too.
In this regime, only quantitative differences with respect to the ideal model are encountered. The flow evolution in fact depends on total, or stagnation, thermodynamic conditions. For example, the Mach number evolution of an ideal gas in a supersonic nozzle depends only on the heat capacity ratio (namely on the fluid) and on the exhaust-to-stagnation pressure ratio. Considering real-gas effects, instead, even fixing the fluid and the pressure ratio, different total states yield different Mach profiles.
Typically, for single-phase fluids made of simple molecules, only the ideal gasdynamic regime can be reached, even for thermodynamic conditions very close to saturation. It is for example the case of diatomic or triatomic molecules, such as nitrogen or carbon dioxide, which can only experience small departure from the ideal behavior. | 0 | Theoretical and Fundamental Chemistry |
A common kind of hydrolysis occurs when a salt of a weak acid or weak base (or both) is dissolved in water. Water spontaneously ionizes into hydroxide anions and hydronium cations. The salt also dissociates into its constituent anions and cations. For example, sodium acetate dissociates in water into sodium and acetate ions. Sodium ions react very little with the hydroxide ions whereas the acetate ions combine with hydronium ions to produce acetic acid. In this case the net result is a relative excess of hydroxide ions, yielding a basic solution.
Strong acids also undergo hydrolysis. For example, dissolving sulfuric acid () in water is accompanied by hydrolysis to give hydronium and bisulfate, the sulfuric acid's conjugate base. For a more technical discussion of what occurs during such a hydrolysis, see Brønsted–Lowry acid–base theory. | 0 | Theoretical and Fundamental Chemistry |
This is a special category of chain-growth supramolecular polymerization, where the monomer nucleates only in an early stage of polymerization to generate "seeds" and becomes active for polymer chain elongation upon further addition of a new batch of monomer. A secondary nucleation is suppressed in most of the case and thus possible to realize a narrow polydispersity of the resulting supramolecular polymer. In 2007, Ian Manners and Mitchell A. Winnik introduced this concept using a polyferrocenyldimethylsilane–polyisoprene diblock copolymer as the monomer, which assembles into cylindrical micelles. When a fresh feed of the monomer is added to the micellar "seeds" obtained by sonication, the polymerization starts in a living polymerization manner. They named this method as crystallization-driven self-assembly (CDSA) and is applicable to construct micron-scale supramolecular anisotropic structures in 1D–3D. A conceptually different seeded supramolecular polymerization was shown by Kazunori Sugiyasu in a porphyrin-based monomer bearing amide-appended long alkyl chains. At low temperature, this monomer preferentially forms spherical J-aggregates while fibrous H-aggregates at higher temperature. By adding a sonicated mixture of the J-aggregates ("seeds") into a concentrated solution of the J-aggregate particles, long fibers can be prepared via living seeded supramolecular polymerization. Frank Würthner achieved similar seeded supramolecular polymerization of amide functionalized perylene bisimide as monomer. Importantly, the seeded supramolecular polymerization is also applicable to prepare supramolecular block copolymers. | 0 | Theoretical and Fundamental Chemistry |
Arsenic is a cause of mortality throughout the world; associated problems include heart, respiratory, gastrointestinal, liver, nervous and kidney diseases.
Arsenic interferes with cellular longevity by allosteric inhibition of an essential metabolic enzyme pyruvate dehydrogenase (PDH) complex, which catalyzes the oxidation of pyruvate to acetyl-CoA by NAD. With the enzyme inhibited, the energy system of the cell is disrupted resulting in a cellular apoptosis episode. Biochemically, arsenic prevents use of thiamine resulting in a clinical picture resembling thiamine deficiency. Poisoning with arsenic can raise lactate levels and lead to lactic acidosis.
Genotoxicity involves inhibition of DNA repair and DNA methylation. The carcinogenic effect of arsenic arises from the oxidative stress induced by arsenic. Arsenic's high toxicity naturally led to the development of a variety of arsenic compounds as chemical weapons, e.g. dimethylarsenic chloride. Some were employed as chemical warfare agents, especially in World War I. This threat led to many studies on antidotes and an expanded knowledge of the interaction of arsenic compounds with living organisms. One result was the development of antidotes such as British anti-Lewisite. Many such antidotes exploit the affinity of As(III) for thiolate ligands, which convert highly toxic organoarsenicals to less toxic derivatives. It is generally assumed that arsenates bind to cysteine residues in proteins.
By contrast, arsenic oxide is an approved and effective chemotherapeutic drug for the treatment of acute promyelocytic leukemia (APL). | 1 | Applied and Interdisciplinary Chemistry |
The occultists who were responsible for the popularization of the paraphrase generally understood it in the context of Emanuel Swedenborg's (1688–1772) doctrine of the correspondence between different planes of existence, a strongly elaborated version of the classical macrocosm–microcosm analogy. This interpretation was pioneered by Helena P. Blavatsky (1831–1891), whose works contain some of the earliest occurrences of the phrase as an independent axiom. Generally writing from a perennialist perspective, Blavatsky associated the phrase with a number of historically unrelated thought systems such as Pythagoreanism, Kabbalah and Buddhism.
From Blavatskys Isis Unveiled' (1877): | 1 | Applied and Interdisciplinary Chemistry |
Much of the Martian surface is deeply covered by dust as fine as talcum powder. The global predominance of dust obscures the underlying bedrock, making spectroscopic identification of primary minerals impossible from orbit over many areas of the planet. The red/orange appearance of the dust is caused by iron(III) oxide (nanophase FeO) and the iron(III) oxide-hydroxide mineral goethite.
The Mars Exploration Rovers identified magnetite as the mineral responsible for making the dust magnetic. It probably also contains some titanium.
The global dust cover and the presence of other wind-blown sediments has made soil compositions remarkably uniform across the Martian surface. Analysis of soil samples from the Viking landers in 1976 shows that the soils consist of finely broken up basaltic rock fragments and are highly enriched in sulphur and chlorine, probably derived from volcanic gas emissions. | 0 | Theoretical and Fundamental Chemistry |
The development of fluorometers allowed chlorophyll fluorescence analysis to become a common method in plant research. Chlorophyll fluorescence analysis has been revolutionized by the invention of the Pulse-Amplitude-Modulation (PAM) technique and availability of the first commercial modulated chlorophyll fluorometer PAM-101 (Walz, Germany). By modulating the measuring light beam (microsecond-range pulses) and parallel detection of the excited fluorescence the relative fluorescence yield (Ft) can be determined in the presence of ambient light. Crucially, this means chlorophyll fluorescence can be measured in the field even in full sunlight.
Today, chlorophyll fluorometers are designed for measuring many different plant mechanisms. The measuring protocols: F/F and OJIP measure the efficiency of Photosystem II samples at a common and known dark adapted state. These protocols are useful in measuring many types of plant stress. Bernard Genty's light adapted measuring protocol ΔF/F’, or Y(II), is an effective and sensitive way to measure plant samples under ambient or artificial lighting conditions. However, since Y(II) values also change with light intensity, one should compare samples at the same light intensity unless light stress is the focus of the measurement. Y(II) can be more sensitive to some types of plant stress than F/F, such as heat stress.
Other plant mechanism measuring protocols have also been developed. When a chloroplast absorbs light, some of the light energy goes to photochemistry, some goes to regulated heat dissipation, and some goes to unregulated heat dissipation. Various chlorophyll fluorescence measuring parameters exist to measure all of these events. In the lake model, q measures photochemical quenching, Y(NYO) measures plant regulated heat dissipation, and Y(NO) measures unregulated heat dissipation. An older quenching protocol, called the puddle model, uses q for photochemical quenching, q for nonphotochemical quenching of both regulated and unregulated heat dissipation and NPQ for an estimate of nonphotochemical quenching. NPQ has also been resurrected to the lake model mathematically.
In addition, the parameters q, and pNPQ have been developed to measure the photoprotective xanthophyll cycle. q is a measure of state transitions. q is a measure of chloroplast migration, and q is a measure of plant photoinhibition.
At lower actinic light levels NPQ = qE+qT+qI
At high actinic light levels NPQ = qE+qM=qI
Some fluorometers are designed to be portable and operated in one hand.
Consistent further development into imaging fluorometers facilitate the visualization of spatial heterogeneities in photosynthetic activity of samples. These heterogeneities naturally occur in plant leaves for example during growths, various environmental stresses or pathogen infection. Thus knowledge about sample heterogeneities is important for correct interpretation of the photosynthetic performance of the plant sample. High performance imaging fluorometer systems provide options to analyze single cell/single chloroplast as well as sample areas covering whole leaves or plants. | 0 | Theoretical and Fundamental Chemistry |
Joule heating is referred to as ohmic heating or resistive heating because of its relationship to Ohms Law. It forms the basis for the large number of practical applications involving electric heating. However, in applications where heating is an unwanted by-product of current use (e.g., load losses in electrical transformers) the diversion of energy is often referred to as resistive loss'. The use of high voltages in electric power transmission systems is specifically designed to reduce such losses in cabling by operating with commensurately lower currents. The ring circuits, or ring mains, used in UK homes are another example, where power is delivered to outlets at lower currents (per wire, by using two paths in parallel), thus reducing Joule heating in the wires. Joule heating does not occur in superconducting materials, as these materials have zero electrical resistance in the superconducting state.
Resistors create electrical noise, called Johnson–Nyquist noise. There is an intimate relationship between Johnson–Nyquist noise and Joule heating, explained by the fluctuation-dissipation theorem. | 0 | Theoretical and Fundamental Chemistry |
There are nine sugar nucleotides in humans which act as glycosyl donors and they can be classified depending on the type of the nucleoside forming them:
*Uridine Diphosphate: UDP-α-D-Glc, UDP-α-D-Gal, UDP-α-D-GalNAc, UDP-α-D-GlcNAc, UDP-α-D-GlcA, UDP-α-D-Xyl
*Guanosine Diphosphate: GDP-α-D-Man, GDP-β-L-Fuc.
*Cytidine Monophosphate: CMP-β-D-Neu5Ac; in humans, it is the only nucleotide sugar in the form of nucleotide monophosphate.
*Cytidine Diphosphate: CDP-D-Ribitol (i.e. CMP-[ribitol phosphate]); though not a sugar, the phosphorylated sugar alcohol ribitol phosphate is incorporated into matriglycan as if it were a monosaccharide.
In other forms of life many other sugars are used and various donors are utilized for them. All five of the common nucleosides are used as a base for a nucleotide sugar donor somewhere in nature. As examples, CDP-glucose and TDP-glucose give rise to various other forms of CDP and TDP-sugar donor nucleotides. | 0 | Theoretical and Fundamental Chemistry |
Graphene is viable for photothermal therapy. An 808 nm laser at a power density of 2 W/cm was used to irradiate the tumor sites on mice for 5 minutes. As noted by the authors, the power densities of lasers used to heat gold nanorods range from 2 to 4 W/cm. Thus, these nanoscale graphene sheets require a laser power on the lower end of the range used with gold nanoparticles to photothermally ablate tumors.
In 2012, Yang et al. incorporated the promising results regarding nanoscale reduced graphene oxide reported by Robinson et al. into another in vivo mice study., an order of magnitude lower than previously required power densities. This study demonstrates the higher efficacy of nanoscale reduced graphene oxide sheets as compared to both nanoscale graphene sheets and gold nanorods. | 0 | Theoretical and Fundamental Chemistry |
Local hormones are a large group of signaling molecules that do not circulate within the blood. Local hormones are produced by nerve and gland cells and bind to either neighboring cells or the same type of cell that produced them. Local hormones are activated and inactivated quickly. They are released during physical work and exercise. They mainly control smooth and vascular muscle dilation. Strength of response is dependent upon the concentration of receptors of target cell and the amount of ligand ( the specific local hormone).
Eicosanoids (ī′kō-să-noydz; eicosa = twenty, eidos = formed) are a primary type of local hormone. These local hormones are polyunsaturated fatty acid derivatives containing 20 carbon atoms and fatty acids derived from phospholipids in the cell membrane or from diet. Eicosanoids initiate either autocrine stimulation or paracrine stimulation. There are two main types of eicosanoids: prostaglandins and leukotrienes, which initiate either autocrine stimulation or paracrine stimulation. Eicosanoids are the result of a ubiquitous pathway which first produces arachidonic acid, and then the eicosanoid product.
Prostaglandins are the most diverse category of eicosanoids and are thought to be synthesized in most tissues of the body. This type of local hormone stimulates pain receptors and increases the inflammatory response. Nonsteroidal anti-inflammatory drugs stop the formation of prostaglandins, thus inhibiting these responses.
Leukotrienes are a type of eicosanoids that are produced in leukocytes and function in inflammatory mediation.
Paracrines (para- = beside or near) are local hormones that act on neighboring cells. This type of signaling involves the secretion of paracrine factors, which travel a short distance in the extracellular environment to affect nearby cells. These factors can be excitatory or inhibitory. There are a few families of factors that are very important in embryo development including fibroblast growth factor secreted them.
Juxtacrines (juxta = near) are local hormones that require close contact and act on either the cell which emitted them or on adjacent cells. | 1 | Applied and Interdisciplinary Chemistry |
Stray light is unwanted wavelength radiation reaching the incorrect detector element. It generates erroneous electronic counts not related to designed spectral signal for the pixel or element of the detector array. It can come from light scatter and reflection of imperfect optical elements as well as higher order diffraction effects. The second order effect can be removed or at least dramatically reduced, by installing order sorting filters before the detector.
A Si detectors sensitivity to visible and NIR is nearly an order of magnitude larger than that in the UV range. This means that the pixels at the UV spectral position respond to stray light in visible and NIR much more strongly than to their own designed spectral signal. Therefore, the stray light impacts in UV region are much more significant as compared to visible and NIR pixels. This situation gets worse the shorter the wavelength.
When measuring broad band light with small fraction of UV signals, the stray light impact can sometimes be dominant in the UV range since the detector pixels are already struggling to get enough UV signals from the source. For this reason, calibration using QTH standard lamp can have huge errors (more than 100%) below 350 nm and Deuterium standard lamp is required for more accurate calibration in this region. In fact, absolute light measurement in the UV region can have large errors even with the correct calibration when majority of the electronic counts in these pixels is result of the stray light (longer wavelength strikes instead of the actual UV light). | 0 | Theoretical and Fundamental Chemistry |
Carbon tetrachloride was widely used as a fumigant to kill insect pests in stored grain. It was employed in a mixture known as 80/20, that was 80% carbon tetrachloride and 20% carbon disulfide. The United States Environmental Protection Agency banned its use in 1985.
Another carbon tetrachloride fumigant preparation mixture contained acrylonitrile. Carbon tetrachloride reduced the flammability of the mixture. Most common trade names for the preparation were Acritet, Carbacryl and Acrylofume. The most common preparation, Acritet, was prepared with 34 percent acrylonitrile and 66 percent carbon tetrachloride. | 1 | Applied and Interdisciplinary Chemistry |
Biological probe or bio-probes are used to collect samples for microbiological analysis. Microorganisms can accelerate the corrosion process, so monitoring the corrosion caused by them is effective in timely notification and preventive measures. | 1 | Applied and Interdisciplinary Chemistry |
In vertebrates the bc complex, or Complex III, contains 11 subunits: 3 respiratory subunits, 2 core proteins and 6 low-molecular weight proteins. Proteobacterial complexes may contain as few as three subunits. | 1 | Applied and Interdisciplinary Chemistry |
An isothermal titration calorimeter is composed of two identical cells made of a highly efficient thermally conducting and chemically inert material such as Hastelloy alloy or gold, surrounded by an adiabatic jacket. Sensitive thermopile/thermocouple circuits are used to detect temperature differences between the reference cell (filled with buffer or water) and the sample cell containing the macromolecule. Prior to addition of ligand, a constant power (<1 mW) is applied to the reference cell. This directs a feedback circuit, activating a heater located on the sample cell. During the experiment, ligand is titrated into the sample cell in precisely known aliquots, causing heat to be either taken up or evolved (depending on the nature of the reaction). Measurements consist of the time-dependent input of power required to maintain equal temperatures between the sample and reference cells.
In an exothermic reaction, the temperature in the sample cell increases upon addition of ligand. This causes the feedback power to the sample cell to be decreased (remember: a reference power is applied to the reference cell) in order to maintain an equal temperature between the two cells. In an endothermic reaction, the opposite occurs; the feedback circuit increases the power in order to maintain a constant temperature (isothermal operation).
Observations are plotted as the power needed to maintain the reference and the sample cell at an identical temperature against time. As a result, the experimental raw data consists of a series of spikes of heat flow (power), with every spike corresponding to one ligand injection. These heat flow spikes/pulses are integrated with respect to time, giving the total heat exchanged per injection. The pattern of these heat effects as a function of the molar ratio [ligand]/[macromolecule] can then be analyzed to give the thermodynamic parameters of the interaction under study.
To obtain an optimum result, each injection should be given enough time for a reaction equilibrium to reach. Degassing samples is often necessary in order to obtain good measurements as the presence of gas bubbles within the sample cell will lead to abnormal data plots in the recorded results. The entire experiment takes place under computer control.
Direct titration is performed most commonly with ITC to obtain the thermodynamic data, by binding two components of the reaction directly to each other. However, many of the chemical reactions and binding interactions may have higher binding affinity above what is desirable with the c-window. To troubleshoot the limitation of c-window and conditions for certain binding interactions, various different methods of titration can be performed. In some cases, simply doing a reverse titration of changing the samples between the injection syringe and sample cell can solve the issue, depending on the binding mechanism. For most of the high or low affinity bindings require chelation or competitive titration. This method is done by loading pre-bound complex solution in the sample cell, and chelating one of the components out with a reagent of higher observed binding affinity within the desirable c-window. | 0 | Theoretical and Fundamental Chemistry |
Scheele was born in Stralsund, in western Pomerania, which at the time was a Swedish Dominion inside the Holy Roman Empire. Scheele's father, Joachim (or Johann) Christian Scheele, was a grain dealer and brewer from a respected Pomeranian family. His mother was Margaretha Eleanore Warnekros.
Friends of Scheeles parents taught him the art of reading prescriptions and the meaning of chemical and pharmaceutical signs. Then, in 1757, at the age of fourteen, Carl was sent to Gothenburg as an apprentice pharmacist to another family friend and apothecary, Martin Andreas Bauch. Scheele retained this position for eight years. During this time he ran experiments late into the night and read the works of Nicolas Lemery, Caspar Neumann, Johann von Löwenstern-Kunckel and Georg Ernst Stahl (the champion of the phlogiston theory). Much of Scheeles later theoretical speculations were based upon Stahl.
In 1765 Scheele worked under the progressive and well-informed apothecary C. M. Kjellström in Malmö, and became acquainted with Anders Jahan Retzius who was a lecturer at the University of Lund and later a professor of chemistry at Stockholm. Scheele arrived in Stockholm between 1767 and 1769 and worked as a pharmacist. During this period he discovered tartaric acid and with his friend, Retzius, studied the relation of quicklime to calcium carbonate. While in the capital, he also became acquainted with figures including Abraham Bäck, Peter Jonas Bergius, Bengt Bergius and Carl Friedreich von Schultzenheim.
In the fall of 1770 Scheele became director of the laboratory of the great pharmacy of Locke, at Uppsala, about 65 km (40 mi) north of Stockholm. The laboratory supplied chemicals to Professor of Chemistry Torbern Bergman. A friendship developed between Scheele and Bergman after Scheele analyzed a reaction which Bergman and his assistant, Johan Gottlieb Gahn, could not resolve. The reaction was between melted saltpetre and acetic acid that produced a red vapor. Further study of this reaction later led to Scheeles discovery of oxygen (see "The theory of phlogiston" below). Based upon this friendship and respect, Scheele was given free use of Bergmans laboratory. Both men were profiting from their working relationship. In 1774 Scheele was nominated by Peter Jonas Bergius to be a member of the Royal Swedish Academy of Sciences and was elected 4 February 1775. In 1775 Scheele also managed for a short time a pharmacy in Köping. Between the end of 1776 and the beginning of 1777 Scheele established his own business there.
On 29 October 1777, Scheele took his seat for the first and only time at a meeting of the Academy of Sciences and on 11 November passed the examination as apothecary before the Royal Medical College, doing so with the highest honours. After his return to Köping he devoted himself, outside of his business, to scientific researches which resulted in a long series of important papers.
Isaac Asimov called him "hard-luck Scheele" because he made a number of chemical discoveries that were later credited to others. | 1 | Applied and Interdisciplinary Chemistry |
Though the effects of transposition can sometimes manifest phenotypically, and indeed, this effect led to their discovery, transposons can be difficult for the cellular machinery to detect. Many TEs contain stretches of genuine coding DNA, copied from the host, and there is no distinct structure, code, or identifying characteristic of any kind that would allow a cell to recognize the full range of transposable elements with accuracy. Even besides coding for functional proteins or RNAs, some transposons, like class II elements, contain code copied from the nearby strand, allowing them to blend in. Given that the preceding is true, it must be that transposons are recognized more by their effect than their structure. Thus, cell machinery, as detailed in the next section, exists that is capable of detecting transcripts that are atypical of host genomes, such as:
* Double-stranded RNAs (dsRNAs), which are indicative of both retroviruses and transposons
and, more specifically:
* Small interfering RNAs (siRNAs), which are processed from dsRNA transcribed from inverted repeating elements in the transposon code; a short sense and anti-sense strand are created, which form dsRNA
* MicroRNAs (miRNAs), which are similar to siRNAs, but have an imperfect base pair complement; these are usually formed as a result of shared complementarity between a transposon and a host gene mRNA transcript | 1 | Applied and Interdisciplinary Chemistry |
The FutureGen Industrial Alliance is a consortium of 10 power producers and electric utilities from around the globe. | 1 | Applied and Interdisciplinary Chemistry |
Metallabenzene complexes have been classified into three varieties; in such compounds, the parent acyclic hydrocarbon ligand is viewed as the anion CH. The 6 π electrons in the metallacycle conform to the Hückel (4n+2) theory. | 0 | Theoretical and Fundamental Chemistry |
Self-regulating heat tracing tapes are cables whose resistance varies with temperature - low resistance for temperatures below the cable set point and high resistance for temperatures above the cable set point. When the cable temperature reaches the set point, the resistance reaches a high point, resulting in no more heat being supplied.
These cables use two parallel bus wires which carry electricity but do not create significant heat. They are encased in a semi-conductive polymer. This polymer is loaded with carbon; as the polymer element heats, it allows less current to flow so the cable is inherently power saving and only delivering heat and power where and when required by the system. The cables are manufactured and then irradiated and by varying both the carbon content and the dosage then different tape with different output characteristics can be produced. The benefits of this cable are the ability to cut to length in the field. It is more rugged, and much more reliable than a constant wattage cable; it cannot over-heat itself so it can be crossed over, but it is bad practice to install tape in this way. Self-regulating and constant wattage heating cables have specific maximum exposure temperature, which means that if they are subject to high temperatures then the tape can be damaged beyond repair.
Also self-limiting tapes are subject to higher inrush currents on cold starting up similar to an induction motor, so a higher rated contactor is required. | 1 | Applied and Interdisciplinary Chemistry |
NADH is oxidized into NAD, H ions, and electrons by an enzyme. FADH is also oxidized into H ions, electrons, and FAD. As those electrons travel farther through the electron transport chain in the inner membrane, energy is gradually released and used to pump the hydrogen ions from the splitting of NADH and FADH into the space between the inner membrane and the outer membrane (called the intermembrane space), creating an electrochemical gradient.
This electrochemical gradient creates potential energy (see ) across the inner mitochondrial membrane known as the proton-motive force. As a result, chemiosmosis occurs, and the enzyme ATP synthase produces ATP from ADP and a phosphate group. This harnesses the potential energy from the concentration gradient formed by the amount of H ions. H ions passively pass into the mitochondrial matrix by the ATP synthase, and later help to re-form HO (water).
The electron transport chain requires a varying supply of electrons in order to properly function and generate ATP. However, the electrons that have entered the electron transport chain would eventually pile up like cars traveling down a blocked one-way street. Those electrons are finally accepted by oxygen (O). As a result, they form two molecules of water (HO). By accepting the electrons, oxygen allows the electron transport chain to continue functioning. The chain is organized in the cristae lumen membrane, i.e. the membrane inside the junction.
The electrons from each NADH molecule can form a total of 3 ATP's from ADPs and phosphate groups through the electron transport chain, while each FADH molecule can produce a total of 2 ATPs.
As a result, 10 NADH molecules (from glycolysis and the Krebs cycle), along with 2 FADH molecules, can form a total of 34 ATPs during aerobic respiration (from a single electron transport chain). This means that combined with the Krebs Cycle and glycolysis, the efficiency for the electron transport chain is about 65%, as compared to only 3.5% efficiency for glycolysis alone. | 1 | Applied and Interdisciplinary Chemistry |
The idea of hydrogen in the nascent state having chemical properties different from those of molecular hydrogen developed the mid-19th century. Alexander Williamson repeatedly refers to nascent hydrogen in his textbook Chemistry for Students, for example writing of the substitution reaction of carbon tetrachloride with hydrogen to form products such as chloroform and dichloromethane that the "hydrogen must for this purpose be in the nascent state, as free hydrogen does not produce the effect". Williamson also describes the use of nascent hydrogen in the earlier work of Marcellin Berthelot. Franchot published a paper on the concept in 1896, which drew a strongly worded response from Tommasi who pointed to his own work that concluded "nascent hydrogen is nothing else than H + x calories".
The term "nascent hydrogen" continued to be invoked into the 20th century. | 0 | Theoretical and Fundamental Chemistry |
Phosphatidylethanols (PEth) are a group of phospholipids formed only in the presence of ethanol via the action of phospholipase D (PLD). It accumulates in blood and is removed slowly, making it a useful biomarker for alcohol consumption. PEth is also thought to contribute to the symptoms of alcohol intoxication. | 1 | Applied and Interdisciplinary Chemistry |
If we evaluate the molecular revolution within the context of biological history, it is easy to note that it is the culmination of a long process which began with the first observations through a microscope. The aim of these early researchers was to understand the functioning of living organisms by describing their organization at the microscopic level. From the end of the 18th century, the characterization of the chemical molecules which make up living beings gained increasingly greater attention, along with the birth of physiological chemistry in the 19th century, developed by the German chemist Justus von Liebig and following the birth of biochemistry at the beginning of the 20th, thanks to another German chemist Eduard Buchner. Between the molecules studied by chemists and the tiny structures visible under the optical microscope, such as the cellular nucleus or the chromosomes, there was an obscure zone, "the world of the ignored dimensions," as it was called by the chemical-physicist Wolfgang Ostwald. This world is populated by colloids, chemical compounds whose structure and properties were not well defined.
The successes of molecular biology derived from the exploration of that unknown world by means of the new technologies developed by chemists and physicists: X-ray diffraction, electron microscopy, ultracentrifugation, and electrophoresis. These studies revealed the structure and function of the macromolecules.
A milestone in that process was the work of Linus Pauling in 1949, which for the first time linked the specific genetic mutation in patients with sickle cell disease to a demonstrated change in an individual protein, the hemoglobin in the erythrocytes of heterozygous or homozygous individuals. | 1 | Applied and Interdisciplinary Chemistry |
A widely accepted explanation is that there is a stabilizing interaction (hyperconjugation) between the unshared electron pair on the endocyclic heteroatom (within the sugar ring) and the σ* orbital of the axial (exocyclic) C–X bond. This causes the molecule to align the donating lone pair of electrons antiperiplanar (180°) to the exocyclic C-X σ bond, lowering the overall energy of the system and causing more stability.
Some authors also question the validity of this hyperconjugation model based on results from the quantum theory of atoms in molecules. While most studies on the anomeric effects have been theoretical in nature, the n–σ* (hyperconjugation) hypothesis has also been extensively criticized on the basis that the electron density redistribution in acetals proposed by this hypothesis is not congruent with the known experimental chemistry of acetals and, in particular, the chemistry of monosaccharides. | 0 | Theoretical and Fundamental Chemistry |
An assay is an investigative (analytic) procedure in laboratory medicine, mining, pharmacology, environmental biology and molecular biology for qualitatively assessing or quantitatively measuring the presence, amount, or functional activity of a target entity. The measured entity is often called the analyte, the measurand, or the target of the assay. The analyte can be a drug, biochemical substance, chemical element or compound, or cell in an organism or organic sample. An assay usually aims to measure an analyte's intensive property and express it in the relevant measurement unit (e.g. molarity, density, functional activity in enzyme international units, degree of effect in comparison to a standard, etc.).
If the assay involves exogenous reactants (the reagents), then their quantities are kept fixed (or in excess) so that the quantity and quality of the target are the only limiting factors. The difference in the assay outcome is used to deduce the unknown quality or quantity of the target in question. Some assays (e.g., biochemical assays) may be similar to chemical analysis and titration. However, assays typically involve biological material or phenomena that are intrinsically more complex in composition or behavior, or both. Thus, reading of an assay may be noisy and involve greater difficulties in interpretation than an accurate chemical titration. On the other hand, older generation qualitative assays, especially bioassays, may be much more gross and less quantitative (e.g., counting death or dysfunction of an organism or cells in a population, or some descriptive change in some body part of a group of animals).
Assays have become a routine part of modern medical, environmental, pharmaceutical, and forensic technology. Other businesses may also employ them at the industrial, curbside, or field levels. Assays in high commercial demand have been well investigated in research and development sectors of professional industries. They have also undergone generations of development and sophistication. In some cases, they are protected by intellectual property regulations such as patents granted for inventions. Such industrial-scale assays are often performed in well-equipped laboratories and with automated organization of the procedure, from ordering an assay to pre-analytic sample processing (sample collection, necessary manipulations e.g. spinning for separation, aliquoting if necessary, storage, retrieval, pipetting, aspiration, etc.). Analytes are generally tested in high-throughput autoanalyzers, and the results are verified and automatically returned to ordering service providers and end-users. These are made possible through the use of an advanced laboratory informatics system that interfaces with multiple computer terminals with end-users, central servers, the physical autoanalyzer instruments, and other automata. | 1 | Applied and Interdisciplinary Chemistry |
A foam is said to be stochastic when the porosity distribution is random. Most foams are stochastic because of the method of manufacture:
* Foaming of liquid or solid (powder) metal
* Vapor deposition (CVD on a random matrix )
* Direct or indirect random casting of a mold containing beads or matrix | 0 | Theoretical and Fundamental Chemistry |
The fundamental problem of cartography is that no map from the sphere to the plane can accurately represent both angles and areas. In general, area-preserving map projections are preferred for statistical applications, while angle-preserving (conformal) map projections are preferred for navigation.
Stereographic projection falls into the second category. When the projection is centered at the Earth's north or south pole, it has additional desirable properties: It sends meridians to rays emanating from the origin and parallels to circles centered at the origin. | 0 | Theoretical and Fundamental Chemistry |
There are several associations managed by school's students :
- lAmicale (BDE) (or Student Union ): It manages the associative and festive life of the school, organizes students foyers functioning, publishes students directory and organizes events like, for example, new students integrations weekend. About ten clubs exist in the association like the Arts' Office, DéméTerre (sustainable development), Theatre Club, Manga Club, Cine Club, Gastronomy Club, study trip, etc.
- Le Bureau des Sports (BDS° (or Sports Office) : It allows students to do sport, to participate in university competitions and organizes events like a nice trip at the month for a weekend or at the Tournoi Inter-Chimie (TIC) in spring. Moreover, the ECPM won this sports and festive event in 2006 which has been organized in Mulhouse.
- Le "Forum Horizon Chimie" (FHC) : Its the ECPMs association that organize a forum which happens every year at la Maison de la Chimie in Paris.
Moreover, a junior company, Strasbourg Chimie Service, allows students-employed to make some punctual missions like chemical analyses, scientific conferences or translations of publications.
It also exists lAmicale des Ingénieurs de Chimie de Strasbourg (Association of the Strasbourgs Engineers of Chemistry). Its an association aiming at conservation and relations strengthening between graduates and students. It has in particular for ultimate objective the creation of a robust and big network ECPM, a very great tool for a successful career.
-Student common room
The ECPM Student common room is the center of the school. It is a place where students can relax after lunch or during off-peak times.
It is a big place where you can find a table football, a billiard table, many couches and tables and even a microwave. In fact, it is possible to eat food you’ve brought. Moreover, there is a mezzanine with a hi-fi system, which makes you think of a nightclub and a terrace which is surrounded by trees and is really cozy.
Everyone has the right to go to the student common room, the students in the engineering cycle and the CPI’s. Furthermore, the BDE and the BDS (respectively student union and sports office) sometime organize parties in the student common room (for example barbecues) to bring the whole school together. For example, there is the Welcome Party every year for new students. | 1 | Applied and Interdisciplinary Chemistry |
NPP2, known in humans as autotaxin, acts primarily in cell motility pathways. With its active site functioning, NPP2 promotes cellular migration at picomolar concentrations. Soluble splice variants of NPP2 are thought to be important to cancer metastasis, and also show angiogenic properties in tumors. | 1 | Applied and Interdisciplinary Chemistry |
Affinine is a monoterpenoid indole alkaloid which can be isolated from plants of the genus Tabernaemontana. Structurally it can be considered a member of the vobasine alkaloid family and may be synthesized from tryptophan. Limited pharmacological testing has indicated that it may be an effective inhibitor of both acetylcholinesterase and butyrylcholinesterase. | 0 | Theoretical and Fundamental Chemistry |
A foil is a solid object with a shape such that when placed in a moving fluid at a suitable angle of attack the lift (force generated perpendicular to the fluid flow) is substantially larger than the drag (force generated parallel to the fluid flow). If the fluid is a gas, the foil is called an airfoil or aerofoil, and if the fluid is water the foil is called a hydrofoil. | 1 | Applied and Interdisciplinary Chemistry |
As a trivalent transition metal, yttrium forms various inorganic compounds, generally in the oxidation state of +3, by giving up all three of its valence electrons. A good example is yttrium(III) oxide (), also known as yttria, a six-coordinate white solid.
Yttrium forms a water-insoluble fluoride, hydroxide, and oxalate, but its bromide, chloride, iodide, nitrate and sulfate are all soluble in water. The Y ion is colorless in solution because of the absence of electrons in the d and f electron shells.
Water readily reacts with yttrium and its compounds to form . Concentrated nitric and hydrofluoric acids do not rapidly attack yttrium, but other strong acids do.
With halogens, yttrium forms trihalides such as yttrium(III) fluoride (), yttrium(III) chloride (), and yttrium(III) bromide () at temperatures above roughly 200 °C. Similarly, carbon, phosphorus, selenium, silicon and sulfur all form binary compounds with yttrium at elevated temperatures.
Organoyttrium chemistry is the study of compounds containing carbon–yttrium bonds. A few of these are known to have yttrium in the oxidation state 0. (The +2 state has been observed in chloride melts, and +1 in oxide clusters in the gas phase.) Some trimerization reactions were generated with organoyttrium compounds as catalysts. These syntheses use as a starting material, obtained from and concentrated hydrochloric acid and ammonium chloride.
Hapticity is a term to describe the coordination of a group of contiguous atoms of a ligand bound to the central atom; it is indicated by the Greek character eta, η. Yttrium complexes were the first examples of complexes where carboranyl ligands were bound to a d-metal center through a η-hapticity. Vaporization of the graphite intercalation compounds graphite–Y or graphite– leads to the formation of endohedral fullerenes such as Y@C. Electron spin resonance studies indicated the formation of Y and (C) ion pairs. The carbides YC, YC, and YC can be hydrolyzed to form hydrocarbons. | 1 | Applied and Interdisciplinary Chemistry |
The receptor occupancy model, which describes agonist and competitive antagonists, was built on the work of Langley, Hill, and Clark. The occupancy model was the first model put forward by Clark to explain the activity of drugs at receptors and quantified the relationship between drug concentration and observed effect. It is based on mass-action kinetics and attempts to link the action of a drug to the proportion of receptors occupied by that drug at equilibrium. In particular, the magnitude of the response is directly proportional to the amount of drug bound, and the maximum response would be elicited once all receptors were occupied at equilibrium. He applied mathematical approaches used in enzyme kinetics systematically to the effects of chemicals on tissues.
He showed that for many drugs, the relationship between drug concentration and biological effect corresponded to a hyperbolic curve, similar to that representing the adsorption of a gas onto a metal surface and fitted the Hill–Langmuir equation. Clark, together with Gaddum, was the first to introduce the log concentration–effect curve and described the now-familiar parallel shift of the log concentration–effect curve produced by a competitive antagonist. Attempts to separate the binding phenomenon and activation phenomenon were made by Ariëns in 1954 and by Stephenson in 1956 to account for the intrinsic activity (efficacy) of a drug (that is, its ability to induce an effect after binding). Classic occupational models of receptor activation failed to provide evidence to directly support the idea that receptor occupancy follows a Langmuir curve as the model assumed leading to the development of alternative models to explain drug behaviour. | 1 | Applied and Interdisciplinary Chemistry |
This list covers common isotopes, most of which are available in very small quantities to the general public in most countries. Others that are not publicly accessible are traded commercially in industrial, medical, and scientific fields and are subject to government regulation. | 0 | Theoretical and Fundamental Chemistry |
Proteins are functional macromolecules responsible for catalysing the biochemical reactions that sustain life. Proteins carry out all functions of an organism, for example photosynthesis, neural function, vision, and movement.
The single-stranded nature of protein molecules, together with their composition of 20 or more different amino acid building blocks, allows them to fold in to a vast number of different three-dimensional shapes, while providing binding pockets through which they can specifically interact with all manner of molecules. In addition, the chemical diversity of the different amino acids, together with different chemical environments afforded by local 3D structure, enables many proteins to act as enzymes, catalyzing a wide range of specific biochemical transformations within cells. In addition, proteins have evolved the ability to bind a wide range of cofactors and coenzymes, smaller molecules that can endow the protein with specific activities beyond those associated with the polypeptide chain alone. | 0 | Theoretical and Fundamental Chemistry |
Fumaric acid is produced based on catalytic isomerisation of maleic acid in aqueous solutions at low pH. It precipitates from the reaction solution. Maleic acid is accessible in large volumes as a hydrolysis product of maleic anhydride, produced by catalytic oxidation of benzene or butane. | 1 | Applied and Interdisciplinary Chemistry |
Common pigments used in phosphorescent materials include zinc sulfide and strontium aluminate. Use of zinc sulfide for safety related products dates back to the 1930s.
The development of strontium aluminate pigments in 1993 was spurred on by the need to find a substitute for glow-in-the-dark materials with high luminance and long phosphorescence, especially those that used promethium. This led to the discovery by Yasumitsu Aoki (Nemoto & Co.) of materials with luminance approximately 10 times greater than zinc sulfide and phosphorescence approximately 10 times longer. This has relegated most zinc sulfide based products to the novelty category. Strontium aluminate based pigments are now used in exit signs, pathway marking, and other safety related signage.
Since both phosphorescence (transition from T to S) and the generation of T from an excited singlet state (e.g., S) via intersystem crossing (ISC) are spin-forbidden processes, most organic materials exhibit insignificant phosphorescence as they mostly fail to populate the excited triplet state, and, even if T is formed, phosphorescence is most frequently outcompeted by non-radiative pathways. One strategy to enhance the ISC and phosphorescence is the incorporation of heavy atoms, which increase spin-orbit coupling (SOC). Additionally, the SOC (and therefore the ISC) can be promoted by coupling n-π* and π-π* transitions with different angular momenta, also known as Mostafa El-Sayed's rule. Such transitions are typically exhibited by carbonyl or triazine derivatives, and most organic room-temperature phosphorescent (ORTP) materials incorporate such moieties. In turn, to inhibit competitive non-radiative deactivation pathways, including vibrational relaxation and oxygen quenching and triplet-triplet annihilations, organic phosphors have to be embedded in rigid matrices such as polymers, and molecular solids (crystals, covalent organic frameworks, and others). | 0 | Theoretical and Fundamental Chemistry |
*Saving on capital expenditure while benefiting from new technologies
* Optimization of existing plant components
* Adaptation of the plant for new or changed products
* Increase in piece number and cycle time
* Guaranteed spare parts availability
* Reduced maintenance costs and increased reliability | 1 | Applied and Interdisciplinary Chemistry |
Again, we can derive the small-disturbance limit for sound waves in a moving medium. Again, starting with
We can linearize these into | 1 | Applied and Interdisciplinary Chemistry |
In ammoxidation, a hydrocarbon is partially oxidized in the presence of ammonia. This conversion is practiced on a large scale for acrylonitrile:
In the production of acrylonitrile, a side product is acetonitrile. On an industrial scale, several derivatives of benzonitrile, phthalonitrile, as well as Isobutyronitrile are prepared by ammoxidation. The process is catalysed by metal oxides and is assumed to proceed via the imine. | 0 | Theoretical and Fundamental Chemistry |
While Diet Coke and Mentos are the most common way to make a soda geyser, they are not the only options. Many consider Diet Coke to be the optimal option. While Diet Coke has been studied and suggested that it has the strongest effect, at least one other study has demonstrated that all diet sodas essentially work equally well within experimental error. Nevertheless, any carbonated beverage will work. As for the Mentos, many things work to nucleate carbonated beverages such as other candy, metal and ceramic spheres, and even sand. | 1 | Applied and Interdisciplinary Chemistry |
Ketone levels can be measured by testing urine, blood or breath. There are limitations in directly comparing these methods as they measure different ketone bodies. | 1 | Applied and Interdisciplinary Chemistry |
The possibility has been proposed and studied, both theoretically and experimentally, of implementing an orthogonal system inside cells independent of the cellular genetic material in order to make a completely safe system, with the possible increase in encoding potentials.
Several groups have focused on different aspects:
* Novel backbones and base pairs as discussed above;
* XNA artificial replication and transcription polymerases starting generally from T7 RNA polymerase;
* (16S ribosomal sequences with altered anti-Shine-Dalgarno sequences allowing the translation of only orthogonal mRNA with a matching altered Shine-Dalgarno sequence; and
* Novel tRNA encoding non-natural aminoacids for an expanded genetic code. | 1 | Applied and Interdisciplinary Chemistry |
Two types mannose-6-phosphate can recognize phosphorylated saccharide. One is cation-dependent and the other does not require cation to activate. | 0 | Theoretical and Fundamental Chemistry |
Cobalt carbonyl and rhodium complexes catalyse the hydroformylation of formaldehyde and ethylene oxide to give hydroxyacetaldehyde and 3-hydroxypropanal, which can then be hydrogenated to ethylene glycol and propane-1,3-diol, respectively. The reactions work best when the solvent is basic (such as pyridine).
In the case of dicobalt octacarbonyl or Co(CO) as a catalyst, pentan-3-one can arise from ethene and CO, in the absence of hydrogen. A proposed intermediate is the ethylene-propionyl species [CHC(O)Co(CO)(ethene)] which undergoes a migratory insertion to form [CHCOCHCHCo(CO)]. The required hydrogen arises from the water shift reaction. For details, see
If the water shift reaction is not operative, the reaction affords a polymer containing alternating carbon monoxide and ethylene units. Such aliphatic polyketones are more conventionally prepared using palladium catalysts.
Functionalized olefins such as allyl alcohol can be hydroformylated. The target product 1,4-butanediol and its isomer is obtained with isomerization free catalysts such as rhodium-triphenylphosphine complexes. The use of the cobalt complex leads by isomerization of the double bond to n-propanal. The hydroformylation of alkenyl ethers and alkenyl esters occurs usually in the α-position to the ether or ester function.
The hydroformylation of acrylic acid and methacrylic acid in the rhodium-catalyzed process leads to the Markovnikov product in the first step. By variation of the reaction conditions the reaction can be directed to different products. A high reaction temperature and low carbon monoxide pressure favors the isomerization of the Markovnikov product to the thermodynamically more stable β-isomer, which leads to the n-aldehyde. Low temperatures and high carbon monoxide pressure and an excess of phosphine, which blocks free coordination sites, can lead to faster hydroformylation in the α-position to the ester group and suppress the isomerization. | 0 | Theoretical and Fundamental Chemistry |
In an unsustainable system there is insufficient maintenance of the water networks, especially in the major pipe lines in urban areas. The system deteriorates and then needs rehabilitation or renewal.
Householders and sewage treatment plants can both make the water supply networks more efficient and sustainable. Major improvements in eco-efficiency are gained through systematic separation of rainfall and wastewater. Membrane technology can be used for recycling wastewater.
The municipal government can develop a “Municipal Water Reuse System” which is a current approach to manage the rainwater. It applies a water reuse scheme for treated wastewater, on a municipal scale, to provide non-potable water for industry, household and municipal uses. This technology consists in separating the urine fraction of sanitary wastewater, and collecting it for recycling its nutrients. The feces and graywater fraction is collected, together with organic wastes from the households, using a gravity sewer system, continuously flushed with non-potable water. The water is treated anaerobically and the biogas is used for energy production.
The sustainable water supply system is an integrated system including water intake, water utilization, wastewater discharge and treatment and water environmental protection. It requires reducing freshwater and groundwater usage in all sectors of consumption. Developing sustainable water supply systems is a growing trend, because it serves people's long-term interests. There are several ways to reuse and recycle the water, in order to achieve long-term sustainability, such as:
* Gray water re-use and treatment: gray water is wastewater coming from baths, showers, sinks and washbasins. If this water is treated it can be used as a source of water for uses other than drinking. Depending on the type of gray water and its level of treatment, it can be re-used for irrigation and toilet flushing. According to an investigation about the impacts of domestic grey water reuse on public health, carried out by the New South Wales Health Centre in Australia in the year 2000, grey water contains less nitrogen and fecal pathogenic organisms than sewage, and the organic content of grey water decomposes more rapidly.
* Ecological treatment systems use little energy: there are many applications in gray water re-use, such as reed beds, soil treatment systems and plant filters. This process is ideal for gray water re-use, because of easier maintenance and higher removal rates of organic matter, ammonia, nitrogen and phosphorus.
Other possible approaches to scoping models for water supply, applicable to any urban area, include the following:
* Sustainable drainage system
* Borehole extraction
* Intercluster groundwater flow
* Canal and river extraction
* Aquifer storage
* A more user-friendly indoor water use
The Dublin Statement on Water and Sustainable Development is a good example of the new trend to overcome water supply problems. This statement, suggested by advanced economies, has come up with some principles that are of great significance to urban water supply. These are:
# Fresh water is a finite and vulnerable resource, essential to sustain life, development and the environment.
# Water development and management should be based on a participatory approach, involving users, planners and policy-makers at all levels.
# Women play a central part in the provision, management and safeguarding of water. Institutional arrangements should reflect the role of women in water provision and protection.
# Water has an economic value in all its competing uses and should be recognized as an economic good.
From these statements, developed in 1992, several policies have been created to give importance to water and to move urban water system management towards sustainable development. The Water Framework Directive by the European Commission is a good example of what has been created there out of former policies. | 1 | Applied and Interdisciplinary Chemistry |
* Radiation Research Society Vice-President Elect (2023)
* Berkeley Lab Director’s Award for Exceptional Achievement in Tech Transfer (2022)
* UC Berkeley Kenneth N. Raymond Lectureship in Inorganic Chemistry (2022)
* Bakar Faculty Fellow (2021)
* DOE Secretary of Energy Achievement Honor Award - COVID-19 Clinical Testing Teams (2020)
* DOE Secretary of Energy Achievement Honor Award - National Virtual Biotechnology Laboratory (2020)
* Hellman Faculty Fellow (2020)
* AAAS Fellow (2019)
* KAIST Nuclear & Quantum Engineering Pioneer Lecturer (2019)
* American Chemical Society WCC Rising Star award (2017)
* DOE Early Career Award (2014)
* MIT Technology Review Innovators Under 35 – France (2014)
* Berkeley Lab Director’s Award for Exceptional Scientific Achievement (2013)
* Berkeley Lab Women at the Lab Award (2013)
* Radiation Research Society Junior Faculty NCRP Award (2013)
* Cooley’s Anemia Foundation Young Investigator Award (2009) | 0 | Theoretical and Fundamental Chemistry |
Nuclear fission products are the atomic fragments left after a large atomic nucleus undergoes nuclear fission. Typically, a large nucleus like that of uranium fissions by splitting into two smaller nuclei, along with a few neutrons, the release of heat energy (kinetic energy of the nuclei), and gamma rays. The two smaller nuclei are the fission products. (See also Fission products (by element)).
About 0.2% to 0.4% of fissions are ternary fissions, producing a third light nucleus such as helium-4 (90%) or tritium (7%).
The fission products themselves are usually unstable and therefore radioactive. Due to being relatively neutron-rich for their atomic number, many of them quickly undergo beta decay. This releases additional energy in the form of beta particles, antineutrinos, and gamma rays. Thus, fission events normally result in beta and additional gamma radiation that begins immediately after, even though this radiation is not produced directly by the fission event itself.
The produced radionuclides have varying half-lives, and therefore vary in radioactivity. For instance, strontium-89 and strontium-90 are produced in similar quantities in fission, and each nucleus decays by beta emission. But Sr has a 30-year half-life, and Sr a 50.5-day half-life. Thus in the 50.5 days it takes half the Sr atoms to decay, emitting the same number of beta particles as there were decays, less than 0.4% of the Sr atoms have decayed, emitting only 0.4% of the betas. The radioactive emission rate is highest for the shortest lived radionuclides, although they also decay the fastest. Additionally, less stable fission products are less likely to decay to stable nuclides, instead decaying to other radionuclides, which undergo further decay and radiation emission, adding to the radiation output. It is these short lived fission products that are the immediate hazard of spent fuel, and the energy output of the radiation also generates significant heat which must be considered when storing spent fuel. As there are hundreds of different radionuclides created, the initial radioactivity level fades quickly as short lived radionuclides decay, but never ceases completely as longer lived radionuclides make up more and more of the remaining unstable atoms. In fact the short lived products are so predominant that 87 percent decay to stable isotopes within the first month after removal from the reactor core. | 0 | Theoretical and Fundamental Chemistry |
Several pyridine derivatives play important roles in biological systems. While its biosynthesis is not fully understood, nicotinic acid (vitamin B) occurs in some bacteria, fungi, and mammals. Mammals synthesize nicotinic acid through oxidation of the amino acid tryptophan, where an intermediate product, the aniline derivative kynurenine, creates a pyridine derivative, quinolinate and then nicotinic acid. On the contrary, the bacteria Mycobacterium tuberculosis and Escherichia coli produce nicotinic acid by condensation of glyceraldehyde 3-phosphate and aspartic acid. | 0 | Theoretical and Fundamental Chemistry |
One of the earliest ideas for the use of π-conjugated molecules in molecular computation was proposed by Ari Aviram from IBM in 1988. The motivation for this work was to develop theoretical models for mixed-valence type-σ-π-σ-bonded molecules and explore their stereochemical properties for potential applications in molecular devices. The system comprised two π-conjugated systems, 1 and 2, made of oligothiophenes joined by a spiro linkage, and connected to gold electrodes by thiol linkers. π-system 1 is non-conducting in its neutral state, whereas system 2 is electrically conducting in its radical cation form. The twisted structure of the system courtesy of the spiro linkage provides hindrance to the transport of electrons between the two π-systems. However, through electrodes directed toward the linkage, a strong electric field could facilitate electron transfer from system 1 to system 2, with the radical cation going the opposite way.
The first practical realization of molecular logic was courtesy of de Silva and coworkers in their seminal work, in which they constructed a molecular photoionic AND gate with a fluorescent output. While a YES molecular logic gate, as described previously, can convert signals from their ionic to photonic forms (hence the term “photoionic”), they are singular-input-singular-output systems. To build more complex molecular logic architectures, two-input gates, namely AND and OR gates, are needed. Some early works made some progress in this direction, but could not realize a complete truth table as their ionic forms (protonated) could not bind to the substrate in all cases. De Silva and co. constructed an anthracene-based AND gate made up of tertiary amine and benzo-18-crown-6 units, both of which were known to show photoinduced electron transfer (PET) processes. In the system shown, they both acted as receptors, connected to the anthracene-based fluorophore by alkyl spacers. The PET is quenched upon coordination with protons and sodium ions, respectively, for the two receptors, and would lead the anthracene unit to fluoresce. The truth table for an AND gate was completely realized as the system would exhibit a fluorescence output only in the presence of both protons and sodium ions in the system. | 0 | Theoretical and Fundamental Chemistry |
The Journal of Photochemistry was established in 1972 under founding editor-in-chief Richard P. Wayne. Originally published quarterly, by 1987 frequency had increased to monthly.
In 1986, the 38th Council of the American Society for Photobiology (ASP) established a committee to investigate the proposal that the European Society for Photobiology (ESP) share the operation of the ASP official journal, Photochemistry and Photobiology. In 1987, financial and contractual problems prevented agreement and, instead, ESP contracted with Elsevier, leading to the restructuring of the Journal of Photochemistry into two separate journals: the Journal of Photochemistry and Photobiology A: Chemistry, continuing under Richard P. Wayne and covering photochemistry and the Journal of Photochemistry and Photobiology B: Biology under founding editor Giulio Jori, covering photobiology.
The Journal of Photochemistry and Photobiology C: Photochemistry Reviews was first published in 2000 with Akira Fujishima as founding editor-in-chief. When the journal was first established, it aimed to increase from two issues a year to four, an objective achieved and maintained since 2003. | 0 | Theoretical and Fundamental Chemistry |
Epicurus (341–270 BCE) studied atomism with Nausiphanes who had been a student of Democritus. Although Epicurus was certain of the existence of atoms and the void, he was less sure we could adequately explain specific natural phenomena such as earthquakes, lightning, comets, or the phases of the Moon. Few of Epicurus writings survive, and those that do reflect his interest in applying Democritus theories to assist people in taking responsibility for themselves and for their own happiness—since he held there are no gods around that can help them. (Epicurus regarded the role of gods as exemplifying moral ideals.) | 1 | Applied and Interdisciplinary Chemistry |
Neutral alanes are not nucleophilic enough to deliver organic groups to electrophilic substrates. However, upon activation by a nucleophile, the resulting aluminates are highly nucleophilic and add to electrophiles with retention of configuration at the migration carbon. Thus, stereospecific hydroalumination followed by nucleophilic attack provides a method for the stereospecific synthesis of olefins from alkynes. | 0 | Theoretical and Fundamental Chemistry |
The International Generic Sample Number or IGSN is a persistent identifier for sample. As an active persistent identifier it can be resolved through the Handle System. The system is used in production by the System for Earth Sample Registration (SESAR), Geoscience Australia, Commonwealth Scientific and Industrial Research Organisation Mineral Resources, Australian Research Data Commons (ARDC), University of Bremen MARUM, German Research Centre for Geosciences (GFZ), IFREMER Institut Français de Recherche pour l'Exploitation de la Mer, Korea Institute of Geoscience & Mineral Resources (KIGAM), and University of Kiel. Other organisations are preparing the introduction of the IGSN.
The IGSN was developed as the International Geo Sample Number to provide a persistent, globally unique, web resolvable identifier for physical samples. IGSN is both a governance and technical system for assigning globally unique persistent identifiers to physical samples. Even though initially developed for samples in the geosciences, the application of IGSN can be and has already been expanded to other domains that rely on physical samples and collections. To take into account the expanded scope of the application of IGSN beyond the earth and environmental sciences, the IGSN Implementation Organization (IGSN e.V.) voted to change the name of the identifier to International Generic Sample Number (IGSN) and rename the organisation accordingly.
The IGSN preserves the identity of a sample even as it is moved from lab to lab and as data appear in different publications, thus eliminating ambiguity that stems from similar names for samples from the earth. The IGSN unique identifier allows researchers to track the analytical history of a sample and build on previously collected data as new techniques are developed. Additionally, the IGSN provides a link between disparate data generated by different investigators and published in different scientific articles.
In September 2021, the members of IGSN e.V. and DataCite agreed to enter a partnership. Under the partnership, DataCite will provide the IGSN ID registration services and supporting technology to enable the ongoing sustainability of the IGSN PID infrastructure. The IGSN e.V. will facilitate a Community of Communities to promote and support new research and innovation for standard methods of identifying, citing, and locating physical samples. | 0 | Theoretical and Fundamental Chemistry |
In engineering, the mass transfer coefficient is a diffusion rate constant that relates the mass transfer rate, mass transfer area, and concentration change as driving force:
Where:
* is the mass transfer coefficient [mol/(s·m)/(mol/m)], or m/s
* is the mass transfer rate [mol/s]
* is the effective mass transfer area [m]
* is the driving force concentration difference [mol/m].
This can be used to quantify the mass transfer between phases, immiscible and partially miscible fluid mixtures (or between a fluid and a porous solid). Quantifying mass transfer allows for design and manufacture of separation process equipment that can meet specified requirements, estimate what will happen in real life situations (chemical spill), etc.
Mass transfer coefficients can be estimated from many different theoretical equations, correlations, and analogies that are functions of material properties, intensive properties and flow regime (laminar or turbulent flow). Selection of the most applicable model is dependent on the materials and the system, or environment, being studied. | 1 | Applied and Interdisciplinary Chemistry |
Catalytic rate enhancement via dynamic perturbation of surface active sites has been demonstrated experimentally with dynamic electrocatalysis and dynamic photocatalysis. Those results may be explained in the framework of catalytic resonance theory but conclusive evidence is still lacking:
* In 1978, the electro-oxidation of formic acid on a platinum electrode was studied under the application of constant potentials and square-wave pulsed potentials. The latter was found to enhance the current density (and thus catalytic activity) by up to 20 times compared to the potentiostatic conditions, with the optimal wave amplitude and frequency of 600 mV and 2000 Hz, respectively. In 1988, the oxidation of methanol on a platinum electrode was conducted under pulsed potentials between 0.4 and 1.18 V, resulting in an average current almost 100 times higher than the steady-state current at 0.4 V.
* Using the formic acid electro-oxidation reaction, oscillation of the applied electrodynamic potential between 0 and 0.8 volts accelerated the formation rate of carbon dioxide more than an order of magnitude higher (20X) than what was achievable on platinum, the best existing catalyst. The maximum catalytic rate was experimentally observed at a frequency of 100 Hz; slower catalytic rates were observed at higher and lower electrodynamic frequencies. The resonant frequency was interpreted as the oscillation between conditions favorable to formic acid decomposition (0 V) and conditions favorable to form CO (0.8 V).
*The concept of implementing periodic illumination to improve the quantum yield of a typical photocatalytic reaction was first introduced in 1964 by Miller et al. In this work, they showed enhanced photosynthetic efficiency in the conversion of CO to O when the algal culture was exposed to periodic illumination in a Taylor vortex reactor. Sczechowski et al. later implemented the same approach for heterogeneous photocatalysis in 1993, where they demonstrated 5-fold increment in photoefficiency of formate decomposition by cycling between light and dark conditions with periods of 72 ms and 1.45 s respectively. They hypothesized that upon illumination of the catalyst, there is a critical illumination time during which absorbed photons generate oxidizing species (h) on the surface of the catalyst. The generated species or their intermediates go on to react with substrates on the surface or in the bulk. During dark period, adsorption, desorption, and diffusion generally occurs in the absence of photons. After a critical recovery period in the dark, the photocatalyst can efficiently use photons again when photons are reintroduced. A summary of work involving “dynamic” photocatalysis was provided by Tokode et al. in 2016.
* Dynamic promotion of methanol decomposition was demonstrated on 2 nm Pt nanoparticles using pulsed light. The rate acceleration to form H relative to static illumination was attributed to the selective weakening of adsorbed carbon monoxide, thereby also increasing the quantum efficiency of applied light.
*In 2021, Sordello et al. experimentally demonstrated a 50% increase of the quantum yield for the Hydrogen Evolution Reaction (HER) over Pt/TiO nanoparticles via formic acid photoreforming under Controlled Period Illumination (CPI).
Implementation of catalyst dynamics has been proposed to occur by additional methods using oscillating light, electric potential, and physical perturbation. | 0 | Theoretical and Fundamental Chemistry |
The city of Oslo, Norway installed a system for converting domestic food waste to fuel in 2012. A thermal hydrolysis system produces biogas from the food waste, which provides fuel for the city bus system and is also used for agricultural fertilizer. | 0 | Theoretical and Fundamental Chemistry |
Nickel(II) iodide is an inorganic compound with the formula NiI. This paramagnetic black solid dissolves readily in water to give bluish-green solutions, from which crystallizes the aquo complex [Ni(HO)]I (image above). This bluish-green colour is typical of hydrated nickel(II) compounds. Nickel iodides find some applications in homogeneous catalysis.
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In multiphase reactors, the flow regime gives information about the behaviour of the gas phase and its interaction with the continuous liquid phase. The flow regime can vary significantly depending on several factors, including gas and liquid flow rates, geometric aspects of the column (column diameter, column height, sparger type, sparger holes diameter, and eventually, the size of the solid particles) and physical properties of the phases.
In the most general case, four flow regimes can be encountered in bubble column reactors: (1) homogeneous or bubbly flow regime, (2) slug flow regime, (3) churn or heterogeneous flow regime, and (4) annular flow regime.
The homogeneous flow regime takes place at very low superficial gas velocity and can be divided into mono-dispersed and poly-dispersed homogeneous flow regimes. The former is characterized by a mono-dispersed bubble size distribution, the latter by a poly-dispersed one, according to the change in sign of the lift force. Small bubbles with a positive lift coefficient move towards the column wall, and large bubbles with a negative lift coefficient move towards the column center. The heterogeneous flow regime occurs at very high gas velocity and represents a chaotic and unsteady flow pattern, with high liquid recirculation and vigorous mixing. A wide range of bubble sizes is experienced, and the average bubble size is governed by coalescence and breakup phenomena, which determine the flow properties, no longer influenced by the primary bubbles generated at the sparger.
The slug and the annular flow regimes are usually observed in small-diameter bubble columns with an inner diameter of less than 0.15 m. The former is characterized by giant bubbles, named Taylor bubbles, that occupy the entire cross-sectional area of the column. The latter is characterized by a central core of gas surrounded by a thin liquid film. The annular flow regime exists only at very high gas velocity.
When dealing with industrial applications, larger-diameter bubble columns are typically employed so that the slug flow regime is not usually observed due to the so-called Rayleight-Taylor instabilities. The quantification of these instabilities at the reactor-scale is obtained by comparing the dimensionless bubble diameter, , with a critical diameter, :
Where is the bubble column hydraulic diameter, is the surface tension, is the acceleration due to gravity, is the liquid phase density, and is the gas phase density.
For example, at ambient temperature and pressure and considering air and water as working fluids, a bubble column is classified as a large-diameter if it has a hydraulic diameter greater than 0.15 m.
Due to the very high gas velocity, the annular flow regime is not usually observed in industrial bubble columns. Consequently, in a large-scale bubble column, we may have only the bubbly (or homogeneous) and the churn (or heterogenous) flow regimes. Between these flow regimes, a transition region is usually observed, in which the flow field is not as distinct and well defined as in the bubbly-homogeneous and churn-heterogeneous flow regimes.
The boundaries between the flow regimes can be graphically observed in the flow regimes map. | 1 | Applied and Interdisciplinary Chemistry |
SIR proteins are conserved from yeast to humans, and lend their name to a class of mammalian histone deacetylases (Sirtuins, homologs of Sir2). Sirtuins have been implicated in myriad human traits including Alzheimer's and diabetes, and have been proposed to regulate of lifespan. | 1 | Applied and Interdisciplinary Chemistry |
KhAB-500s were typically filled with yperite (R-5) or phosgene (R-10). It was in diameter and about long. Its loaded weight was about including roughly of chemical agent and a impact-fused burst charge.
Upon detonation, the KhAB-500 R-10 would create a hemispherical cloud of gas with a radius of . In ideal weather conditions, the phosgene cloud could produce serious medical effects up to downwind.
The KhAB-500 was carried by Soviet Union era aircraft.
The bomb was removed from service as a result of the Chemical Weapons Convention in the early 1990s. | 1 | Applied and Interdisciplinary Chemistry |
Although there is a large number of simple known ABX perovskites, this number can be greatly expanded if the A and B sites are increasingly doubled / complex AA’BB’X. Ordered double perovskites are usually denoted as ABB’O where disordered are denoted as A(BB’)O. In ordered perovskites, three different types of ordering are possible: rock-salt, layered, and columnar. The most common ordering is rock-salt followed by the much more uncommon disordered and very distant columnar and layered. The formation of rock-salt superstructures is dependent on the B-site cation ordering. Octahedral tilting can occur in double perovskites, however Jahn–Teller distortions and alternative modes alter the B–O bond length. | 0 | Theoretical and Fundamental Chemistry |
TCF7L2 is a transcription factor influencing the transcription of several genes thereby exerting a large variety of functions within the cell. It is a member of the TCF family that can form a bipartite transcription factor (β-catenin/TCF) alongside β-catenin. Bipartite transcription factors can have large effects on the Wnt signalling pathway. Stimulation of the Wnt signaling pathway leads to the association of β-catenin with BCL9, translocation to the nucleus, and association with TCF7L2, which in turn results in the activation of Wnt target genes. The activation of the Wnt target genes specifically represses proglucagon synthesis in enteroendocrine cells. The repression of TCF7L2 using HMG-box repressor (HBP1) inhibits Wnt signalling. Therefore, TCF7L2 is an effector in the Wnt signalling pathway. TCF7L2's role in glucose metabolism is expressed in many tissues such as gut, brain, liver, and skeletal muscle. However, TCF7L2 does not directly regulate glucose metabolism in β-cells, but regulates glucose metabolism in pancreatic and liver tissues. That said, TCF7L2 directly regulates the expression of multiple transcription factors, axon guidance cues, cell adhesion molecules and ion channels in the thalamus.
The TCF7L2 gene encoding the TCF7L2 transcription factor, exhibits multiple functions through its polymorphisms and thus, is known as a pleiotropic gene. Type 2 diabetes T2DM susceptibility is exhibited in carriers of TCF7L2 rs7903146C>T and rs290481T>C polymorphisms. TCF7L2 rs290481T>C polymorphism, however, has shown no significant correlation to the susceptibility to gestational diabetes mellitus (GDM) in a Chinese Han population, whereas the T alleles of rs7903146 and rs1799884 increase susceptibility to GDM in the Chinese Han population. The difference in effects of the different polymorphisms of the gene indicate that the gene is indeed pleiotropic. | 1 | Applied and Interdisciplinary Chemistry |
The natural ability of nanoparticles to self-assemble can be replicated in systems that do not intrinsically self-assemble. Directed self-assembly (DSA) attempts to mimic the chemical properties of self-assembling systems, while simultaneously controlling the thermodynamic system to maximize self-assembly. | 0 | Theoretical and Fundamental Chemistry |
Figure 1 shows four isotherms of the van der Waals equation (abbreviated as vdW) on a pressure, molar volume plane. The essential character of these curves is that:
# at some critical temperature, the slope is negative, , everywhere except at a single point, the critical point, , where both the slope and curvature are zero, ;
# at higher temperatures the slope of the isotherms is everywhere negative (values of for which the equation has 1 real root for );
# at lower temperatures there are two points on each isotherm where the slope is zero (values of , for which the equation has 3 real roots for )
Evaluating the two partial derivatives in 1) using the vdW equation and equating them to zero produces, , and using these in the equation gives .
This calculation can be done algebraically by noting that the vdW equation can be written as a cubic in , which at the critical point is,
. Moreover, at the critical point all three roots coalesce so it can also be written as
Then dividing the first by , and noting that these two cubic equations are the same when all their coefficients are equal gives three equations
whose solution produces the previous results for .
Using these critical values to define reduced properties renders the equation in the dimensionless form used to construct Fig. 1
This dimensionless form is a similarity relation; it indicates that all vdW fluids at the same will plot on the same curve. It expresses the law of corresponding states which Boltzmann described as follows:
This "law" is just a special case of dimensional analysis in which an equation containing 6 dimensional quantities, , and 3 dimensions, [p], [v], [T], must be expressible in terms of 6 − 3 = 3 dimensionless groups. Here is a characteristic molar volume, a characteristic pressure, and a characteristic temperature, and the 3 dimensionless groups are . The reduced properties defined previously are , , and . Recent research has suggested that there is a family of equations of state that depend on an additional dimensionless group, and this provides a more exact correlation of properties. Nevertheless, as Boltzmann observed, the van der Waals equation provides an essentially correct description.
The vdW equation produces , while for most real fluids . Thus most real fluids do not satisfy this condition, and consequently their behavior is only described qualitatively by the vdW equation. However, the vdW equation of state is a member of a family of state equations based on the Pitzer (acentric) factor, , and the liquid metals, Mercury and Cesium, are well approximated by it. | 0 | Theoretical and Fundamental Chemistry |
The Eschweiler–Clarke reaction is a method for methylation of amines. This method avoids the risk of quaternization, which occurs when amines are methylated with methyl halides. | 0 | Theoretical and Fundamental Chemistry |
Pipes are used extensively in commercial and industrial buildings and on industrial plant (e.g. oil refineries) to transfer fluids between items of plant and equipment. Positive identification assists operations personnel to correctly identify plant when carrying out routine or maintenance activities, and for emergency personnel when responding to emergencies. Pipe marking is particularly important for identification where pipes run along pipe racks, through walls and bulkheads and through floors.
A range of corporate, national and international codes, standards and regulations are in use around the world. | 1 | Applied and Interdisciplinary Chemistry |
Bacterial artificial chromosomes (BACs) are circular DNA molecules, usually about 7kb in length, that are capable of holding inserts up to 300kb in size. BAC vectors contain a replicon derived from E. coli F factor, which ensures they are maintained at one copy per cell. Once an insert is ligated into a BAC, the BAC is introduced into recombination deficient strains of E. coli by electroporation. Most BAC vectors contain a gene for antibiotic resistance and also a positive selection marker. The figure to the right depicts a BAC vector being cut with a restriction enzyme, followed by the insertion of foreign DNA that is re-annealed by a ligase. Overall, this is a very stable vector, but they may be hard to prepare due to a single origin of replication just like PACs. | 1 | Applied and Interdisciplinary Chemistry |
It was Kirchhoff's law of thermal radiation in which he proposed an unknown universal law for radiation that led Max Planck to the discovery of the quantum of action leading to quantum mechanics. | 1 | Applied and Interdisciplinary Chemistry |
The "push" in the intercropping scheme is provided by the plants that emit volatile chemicals (kairomones) which repel stemborer moths and drive them away from the main crop (maize or sorghum). The most commonly used species of push plants are legumes of the genus Desmodium (e.g. silverleaf Desmodium, D. uncinatum, and greenleaf Desmodium, D. intortum). The Desmodium is planted in between the rows of maize or sorghum, where they emit volatile chemicals (such as (E)-β-ocimene and (E)-4,8-dimethyl-1,3,7-nonatriene) that repel the stemborer moths. These semiochemicals are also produced in grasses such as maize when they are damaged by insect herbivores, which may explain why they are repellent to stemborers. Being a low-growing plant, Desmodium does not interfere with the growth of crops, but can suppress weeds and help improve soil quality by increasing soil organic matter content, fixing nitrogen, and stabilizing soils from erosion. It also serves as a highly nutritious animal feed and effectively suppresses striga weeds through an allelopathic mechanism. Another plant showing good repellent properties is molasses grass (Melinis minutiflora), a nutritious animal feed with tick-repelling and stemborer larval parasitoid attractive properties. | 1 | Applied and Interdisciplinary Chemistry |
* Reduced water requirements as compared to raceway or pond aquaculture systems.
* Reduced land needs due to the high stocking density
* Site selection flexibility and independence from a large, clean water source.
* Reduction in wastewater effluent volume.
* Increased biosecurity and ease in treating disease outbreaks.
* Ability to closely monitor and control environmental conditions to maximize production efficiency. Similarly, independence from weather and variable environmental conditions. | 1 | Applied and Interdisciplinary Chemistry |
The CompTox Chemicals Dashboard database contains high quality chemical structures and information that have been extensively curated and quality checked, which can be used as a resource for analytical scientists involved in structure identification.
Chemical hazard data in the dashboard comes from both traditional laboratory animal studies and high-throughput screening. Biological data from high-throughput screening is generated by EPA's ToxCast program, the ToxCast data in the database provides information about the assays used and their response potency and efficacy. These data can be found in the bioactivity tab.
The Chemicals Dashboard can be accessed via a web interface or sets of data within it can be downloaded for use offline. The Lists tab can be used to browse and download groups of related chemicals based on their relevance to a specific research topic (such as [https://comptox.epa.gov/dashboard/chemical_lists/CIGARETTES additives in cigarettes] or [https://comptox.epa.gov/dashboard/chemical_lists/DNTEFFECTS chemicals demonstrating effects on neurodevelopmental effects]) or the specific assay endpoints they are covered by.
Within the online dashboard searches can be performed by product/use categories, assay/gene, systematic name, synonym, CAS number, DSSTox Substance ID or InChiKey. Under the Advanced Search tab chemicals can be searched based on their mass or molecular formula. Searches can also be performed for groups of chemicals based on Chemical Name CASRN, InChIKey, DSSTox Substance ID, DSSTox Compound ID, InChIKey Skeleton, MS-Ready Formula, Exact Formula, or Monoisotopic Mass using the batch search function. | 1 | Applied and Interdisciplinary Chemistry |
Another use is in the estimation of gas holdup in a bubble column. In a bubble column, the gas holdup (fraction of a bubble column that is gas at a given time) can be estimated by:
where:
* is the gas holdup fraction
* is the Eötvos number
* is the Froude number
* is the diameter of holes in the column's spargers (holed discs that emit bubbles)
* is the column diameter
* Parameters to are found empirically | 1 | Applied and Interdisciplinary Chemistry |
Thomas Whitwell (24 October 1837 – 5 August 1878) was a British engineer, inventor and metallurgist.
Known as Tom, he was the third son of William and Sarah Whitwell of Kendal. Tom was initially educated at home via private tutors he was sent to the Quaker run York School at 10 years old. In 1858, at 16, he travelled with his elder brother William to Darlington. As apprentice to Alfred Kitching in his locomotive building shop he learned engineering and metallurgy. From there he continued to build his skills, working with Robert Stephenson & Co in Newcastle.
In 1859 he and William started iron-smelting at Thornaby. Iron ore had been discovered in the area four years previously. The brothers designed and built large scale hot blast fire brick stoves that were much larger and more efficient that anything built in the area until that point. By 1873 the three re-built blast furnaces were 80 feet high and 22 feet in diameter and the works had over 750 employees.
In 1878 Tom died due to an accident at his works. A steam explosion caught him and his foreman John Thompson whilst they were investigating a problem with the rolling mill furnace.
The works continued to run under family ownership, under the chairmanship of Tom's nephew William Fry Whitwell until 1922 when they were eventually closed due to a global glut of pig iron. | 1 | Applied and Interdisciplinary Chemistry |
Single-cell transcriptomic assays have allowed reconstruction development trajectories. Branching of these trajectories describes cell differentiation. Various methods have been developed for reconstructing branching developmental trajectories from single-cell transcriptomic data. They use various advanced mathematical concepts from optimal transportation to principal graphs. Some software libraries for reconstruction and visualization of lineage differentiation trajectories are freely available online. | 1 | Applied and Interdisciplinary Chemistry |
Non-Kekulé molecules with two formal radical centers (non-Kekulé diradicals) can be classified into non-disjoint and disjoint by the shape of their two non-bonding molecular orbitals (NBMOs).
Both NBMOs of molecules with non-disjoint characteristics such as trimethylenemethane have electron density at the same atom. According to Hunds rule, each orbital is filled with one electron with parallel spin, avoiding the Coulomb repulsion by filling one orbital with two electrons. Therefore, such molecules with non-disjoint' NBMOs are expected to prefer a triplet ground state.
In contrast, the NBMOs of the molecules with disjoint characteristics such as tetramethyleneethane can be described without having electron density at the same atom. With such MOs, the destabilization factor by the Coulomb repulsion becomes much smaller than with non-disjoint type molecules, and therefore the relative stability of the singlet ground state to the triplet ground state will be nearly equal, or even reversed because of exchange interaction. | 0 | Theoretical and Fundamental Chemistry |
Nucleoside diphosphate (NDP) kinase catalyzes in vivo ATP-dependent synthesis of ribo- and deoxyribonucleoside triphosphates. In mutated Escherichia coli that had a disrupted nucleoside diphosphate kinase, adenylate kinase performed dual enzymatic functions. ADK complements nucleoside diphosphate kinase deficiency. | 1 | Applied and Interdisciplinary Chemistry |
The anions of orthophosphoric acid are orthophosphate (commonly called simply "phosphate") , monohydrogen phosphate , and dihydrogen phosphate . | 0 | Theoretical and Fundamental Chemistry |
Letting , the momentum of the particle, the integrated Boltzmann equation becomes the conservation of momentum equation:
where is the pressure tensor (the viscous stress tensor plus the hydrostatic pressure). | 1 | Applied and Interdisciplinary Chemistry |
In every experiment, it is important to determine the relative concentration of the protein in question, ammonium persulfate, and Tris(2,2′-bipyridyl)dichlororuthenium(II) hexahydrate that will be used in the protein cross-linking experiment. Previous experiments have shown that for amyloid β-protein (Aβ), the peptide assumed to cause toxicity in Alzheimer's disease, the ratio of protein: Ru(Bpy): APS is 1:2:40. The ratio of Ru(Bpy) and APS is suggested to be kept at this ratio, but the appropriate concentration of a given protein can vary. For many proteins that PICUP has not yet been used for, finding the appropriate concentrations can be done through trial and error. Generally, protein concentrations would fall in between 10 and 50μM, dissolved in the corresponding buffer, most likely sodium phosphate if testing for conditions at physiological pH. However, some studies of pure protein suggest that the protein to Ru(Bpy) ratio should be kept at 1:2 as well. This level arises from the fact that the lower amount of Ru(Bpy) can lead to the protein sample appearing to have more than the actual number of higher order oligomers, and a greater amount of Ru(Bpy) can allow for artificial cross-linking byproducts.
The general method for PICUP is as follows:
# The appropriate amount of the protein is pipetted into the polymerase chain reaction tube (PCR).
# Ammonium persulfate (APS) and Tris(2,2′-bipyridyl)dichlororuthenium(II) hexahydrate are added to the sample and mixed briefly.
# The PCR tube is placed in a glass vial to hold it still inside the bellows of the camera that would irradiate the mixture. Upon closing the lid that covers the camera, pressing down the camera shutter illuminates the tube for however long you program the camera to irradiate for. Using the same camera for every replicate of the experiment ensures that the irradiation time and the distance from the light sourced is controlled for every PICUP experiment.
# After the sample in the PCR tube is irradiated, a calculated amount of 1M Dithiothreitol (DTT) is immediately added to the mixture to quench the reaction. If the reaction is not quenched, the oligomers will continually aggregate and lower order oligomers will not be present in the mixture. In addition, if SDS-PAGE is to be used to analyze the oligomer distribution of the proteins after PICUP, DTT would also act as a denaturing agent to the proteins before gel electrophoresis. | 1 | Applied and Interdisciplinary Chemistry |
In physics, backscatter (or backscattering) is the reflection of waves, particles, or signals back to the direction from which they came. It is usually a diffuse reflection due to scattering, as opposed to specular reflection as from a mirror, although specular backscattering can occur at normal incidence with a surface. Backscattering has important applications in astronomy, photography, and medical ultrasonography. The opposite effect is forward scatter, e.g. when a translucent material like a cloud diffuses sunlight, giving soft light. | 0 | Theoretical and Fundamental Chemistry |
Environmentalists such as Dan Becker, director of the Sierra Clubs Global Warming and Energy Program, believes that the term clean coal is misleading: "There is no such thing as clean coal and there never will be. Its an oxymoron." The Sierra Club's Coal Campaign has launched a site refuting the clean coal statements and advertising of the coal industry.
Complaints focus on the environmental impacts of coal extraction, high costs to sequester carbon, and uncertainty of how to manage result pollutants and radionuclides. In reference to sequestration of carbon, concerns exist about whether geologic storage of in reservoirs, aquifers, etc., is indefinite/permanent.
The palaeontologist and influential environmental activist Tim Flannery made the assertion that the concept of clean coal might not be viable for all geographical locations.
Critics also believe that the continuing construction of coal-powered plants (whether or not they use carbon sequestration techniques) encourages unsustainable mining practices for coal, which can strip away mountains, hillsides, and natural areas. They also point out that there can be a large amount of energy required and pollution emitted in transporting the coal to the power plants.
The Reality Coalition, a US non-profit climate organization composed of the Alliance for Climate Protection, the Sierra Club, the National Wildlife Federation, the Natural Resources Defense Council, and the League of Conservation Voters, ran a series of television commercials in 2008 and 2009. The commercials were highly critical of attempts to mitigate coals pollution, stating that without capturing emissions and storing it safely that it cannot be called clean coal'.
Greenpeace is a major opponent of the concept, because they view emissions and wastes as not being avoided but instead transferred from one waste stream to another. According to Greenpeace USAs Executive Director Phil Radford speaking in 2012, "even the industry figures it will take 10 or 20 years to arrive, and we need solutions sooner than that. We need to scale up renewable energy; clean coal' is a distraction from that." | 1 | Applied and Interdisciplinary Chemistry |
Another problem of the parts-per notation is that it may refer to mass fraction, mole fraction or volume fraction. Since it is usually not stated which quantity is used, it is better to write the units out, such as kg/kg, mol/mol or m/m, even though they are all dimensionless. The difference is quite significant when dealing with gases, and it is very important to specify which quantity is being used. For example, the conversion factor between a mass fraction of 1 ppb and a mole fraction of 1 ppb is about 4.7 for the greenhouse gas CFC-11 in air. For volume fraction, the suffix "V" or "v" is sometimes appended to the parts-per notation (e.g. ppmV, ppbv, pptv). However, ppbv and pptv are also often used for mole fractions (which is identical to volume fraction only for ideal gases).
To distinguish the mass fraction from volume fraction or mole fraction, the letter "w" (standing for "weight") is sometimes added to the abbreviation (e.g. ppmw, ppbw).
The usage of the parts-per notation is generally quite fixed within each specific branch of science, but often in a way that is inconsistent with its usage in other branches, leading some researchers to assume that their own usage (mass/mass, mol/mol, volume/volume, mass/volume, or others) is correct and that other usages are incorrect. This assumption sometimes leads them to not specify the details of their own usage in their publications, and others may therefore misinterpret their results. For example, electrochemists often use volume/volume, while chemical engineers may use mass/mass as well as volume/volume, while chemists, the field of occupational safety and the field of permissible exposure limit (e.g. permitted gas exposure limit in air) may use mass/volume. Unfortunatelly, many academic publications of otherwise excellent level fail to specify their use of the parts-per notation, which irritates some readers, especially those who are not experts in the particular fields in those publications, because parts-per-notation, without specifying what it stands for, can mean anything. | 1 | Applied and Interdisciplinary Chemistry |
Gustavs Vanags was born in "Rungas" house of the Schnicken (Sniķeru) manor (now in Ukri Parish, Auce Municipality). He received primary education in the Mitau Classic Gymnasium, and in 1910 enrolled Riga Polytechnic Institute. During the First World War, he, among many, went in evacuation to the inner regions of Russian Empire; after returning from it in 1921, he completed his education in the new-founded University of Latvia and worked at the Faculty of Chemistry, raising to the position of the chair of the Department of organic chemistry. He received his habilitation in 1932.
After Riga Polytechnic Institute was reestablished in 1958, G. Vanags moved to it, serving in the same position as the department chair until 1965. Simultaneously he also worked in the State Institute of Organic Synthesis, where he carried out his research in the chemistry of cyclic β-diketones. He was founder of Riga scholl of organic chemists specializing on β-diketones, which continues up to day (2020). Gustavs Vanags, along with his students, designed and synthesized several compounds of notable application in medicine, agriculture and chemical analysis (omefin, bindon, nitroindandione, rhodenticide diphenadione or ratindan).
Gustavs Vanags died in a sudden death on May 8, 1965, in Riga. He was buried in the Forest Cemetery. | 0 | Theoretical and Fundamental Chemistry |
*1896 - 1899 : Charles Friedel
*1899 - 1907 : Henri Moissan (Nobel Prize in chemistry)
*1907 - 1908 : collective direction
*1908 - 1928 : Camille Chabrié
*1928 - 1938 : Georges Urbain (member of the French Academy of Sciences)
*1938 - 1950 : Louis Hackspill
*1950 - 1961 : Georges Chaudron (member of the French Academy of Sciences)
*1961 - 1976 : Jacques Bénard
*1976 - 1985 : Fernand Coussemant
*1985 - 1987 : Jean Talbot
*1987 - 1992 : Claude Quivoron
*1992 - 1996 : Bernard Trémillon
*1996 - 2005 : Danièle Olivier
*2006 - 2010 : Alain Fuchs
*2010 - 2015 : Valérie Cabuil
*2015–present : Christian Lerminiaux | 1 | Applied and Interdisciplinary Chemistry |
Although the pathogenic role of ANCA is still controversial, in vitro and animal models support the idea that the antibodies have a direct pathological role in the formation of small vessel vasculitides. MPO and PR3 specific ANCA can activate neutrophils and monocytes through their Fc and Fab'2 receptors, which can be enhanced by cytokines which cause neutrophils to display MPO and PR3 on their surface. Aberrant glycosylation of the MPO and PR3 specific ANCA enhances their ability to interact with activating Fc receptors on neutrophils. The activated neutrophils can then adhere to endothelial cells where degranulation occurs. This releases free oxygen radicals and lytic enzymes, resulting in damage to the endothelium via the induction of necrosis and apoptosis. Furthermore, neutrophils release chemoattractive signalling molecules that recruit more neutrophils to the endothelium, acting as a positive feedback loop. Animal models have shown that MPO antibodies can induce necrotizing crescentic glomerulonephritis and systemic small vessel vasculitis. In these animal models the formation of glomerulonephritis and vasculitis can occur in the absence of T-cells, however neutrophils must be present. Although ANCA titres have been noted to have limited correlation with disease activity, except for kidney disease, and with risk of relapse, this is explained by differences in the epitopes and affinity of ANCAs. ANCAs induce excess activation of neutrophils, resulting in the production of neutrophil extracellular traps (NETs), which cause damage to small blood vessels. In addition, in patients with active disease, treated with Rituximab, an anti-CD20 antibody which remove circulating B-cells, clinical remission correlates more to the decreasing number of circulating B-cells than decrease in ANCA titre, which in some patient does not change during treatment. The same study found that clinical relapse in some patients were in association with the return of circulating B-cells. Based on the above observations and that ANCA reactive B-cells can be found in circulation in patients with AAV, an alternative hypothesis have been proposed assigning a direct pathogenic role of these cells, whereby activated neutrophils and ANCA-reactive B-cells engage in intercellular cross-talk, which leads not only to neutrophil degranulation and inflammation but also to the proliferation and differentiation of ANCA-reactive B-cells. However, this hypothesis remains to be tested. | 1 | Applied and Interdisciplinary Chemistry |
* by expression: expressive therapy
** by writing: writing therapy
*** journal therapy
* by play: play therapy
* by art: art therapy
** sensory art therapy
** comic book therapy
* by gardening: horticultural therapy
* by dance: dance therapy
* by drama: drama therapy
* by recreation: recreational therapy
* by music: music therapy | 1 | Applied and Interdisciplinary Chemistry |
Throughout his career, Trefonas has focused on materials science and the chemistry of photolithography. By understanding the chemistry of photoresists used in lithography, he has been able to develop anti-reflective coatings and polymer photoresists that support finely-tuned etching used in the production of integrated circuits.
These materials and techniques make it possible to fit more circuits into a given area. Over time, lithographic technologies have developed to allow lithography to use smaller wavelengths of light. Trefonas has helped to overcome a number of apparent limits to the sizes that are achievable, developing photoresists that are responsive to 436-nm and 365-nm ultraviolet light, and as small as 193 nm deep.
In 1989, Trefonas and others at Aspect Systems Inc. reported on extensive studies of polyfunctional photosensitive groups in positive photoresists. They studied diazonaphthoquinone (DNQ), a chemical compound used for dissolution inhibition of novolak resin in photomask creation. They mathematically modeled effects, predicted possible optimizations, and experimentally verified their predictions. They found that chemically bonding together three of the molecules of DNQ to create a new molecule containing three dissolution inhibitors in a single molecule, led to a better feature contrast, with better resolution and miniaturization. These modified DNQs became known as "polyfunctional photoactive components" (PACs). This approach, which they termed polyphotolysis,
has also been referred to as the "Trefonas Effect."
The technology of trifunctional diazonaphthoquinone PACs has become the industry standard in positive photoresists. Their mechanism has been elucidated and relates to a cooperative behavior of each of the three DNQ units in the new trifunctional dissolution inhibitor molecule. Phenolic strings from the acceptor groups of PACs that are severed from their anchors may reconnect to living strings, replacing two shorter polarized strings with one longer polarized string.
Trefonas has also been a leader in the development of fast etch organic Bottom Antireflective Coating (BARC)
BARC technology minimizes the reflection of light from the substrate when imaging the photoresist. Light that is used to form the latent image in the photoresist film can reflect back from the substrate and compromise feature contrast and profile shape. Controlling interference from reflected light results in the formation of a sharper pattern with less variability and a larger process window.
In 2014, Trefonas and others at Dow were named Heroes of Chemistry by the American Chemical Society, for the development of Fast Etch Organic Bottom Antireflective Coatings (BARCs). In 2016, Trefonas was recognized with The SCI Perkin Medal for outstanding contributions to industrial chemistry. In 2018, Trefonas was named as a Fellow of the SPIE for "achievements in design for manufacturing & compact modeling." Peter Trefonas was elected to the National Academy of Engineering in 2018 for the "invention of photoresist materials and microlithography methods underpinning multiple generations of microelectronics". DuPont Company in 2019 recognized Trefonas with its top recognition, the Lavoisier Medal, for "commercialized electronic chemicals which enabled customers to manufacture integrated circuits with higher density and faster speeds". | 0 | Theoretical and Fundamental Chemistry |
Iminium cations adopt alkene-like geometries: the central C=N unit is nearly coplanar with all four substituents. Unsymmetrical iminium cations can exist as cis and trans isomers. The C=N bonds, which are near 129 picometers in length, are shorter than C-N single bonds. Cis/trans isomers are observed. The C=N distance is slightly shorter in iminium cations than in the parent imine, and computational studies indicate that the C=N bonding is also stronger in iminium vs imine, although the C=N distance contracts only slightly. These results indicate that the barrier for rotation is higher than in the parent imines. | 0 | Theoretical and Fundamental Chemistry |
In an ideal conductor, where atoms are arranged in a perfect lattice structure, the electrons moving through it would experience no collisions and electromigration would not occur. In real conductors, defects in the lattice structure and the random thermal vibration of the atoms about their positions causes electrons to collide with the atoms and scatter, which is the source of electrical resistance (at least in metals; see electrical conduction). Normally, the amount of momentum imparted by the relatively low-mass electrons is not enough to permanently displace the atoms. However, in high-power situations (such as with the increasing current draw and decreasing wire sizes in modern VLSI microprocessors), if many electrons bombard the atoms with enough force to become significant, this will accelerate the process of electromigration by causing the atoms of the conductor to vibrate further from their ideal lattice positions, increasing the amount of electron scattering. High current density increases the number of electrons scattering against the atoms of the conductor, and hence the rate at which those atoms are displaced.
In integrated circuits, electromigration does not occur in semiconductors directly, but in the metal interconnects deposited onto them (see semiconductor device fabrication).
Electromigration is exacerbated by high current densities and the Joule heating of the conductor (see electrical resistance), and can lead to eventual failure of electrical components. Localized increase of current density is known as current crowding. | 0 | Theoretical and Fundamental Chemistry |
Transcription of the msl-2 transcript is regulated by multiple binding sites for fly Sxl at the 5′ UTR. In particular, these poly-uracil sites are located close to a small intron that is spliced in males, but kept in females through splicing inhibition. This splicing inhibition is maintained by Sxl. When present, Sxl will repress the translation of msl2 by increasing translation of a start codon located in a uORF in the 5′ UTR (see above for more information on uORFs). Also, Sxl outcompetes TIA-1 to a poly(U) region and prevents snRNP (a step in alternative splicing) recruitment to the 5′ splice site. | 1 | Applied and Interdisciplinary Chemistry |
There are over 16 million dams in the world that alter carbon transport from rivers to oceans. Using data from the Global Reservoirs and Dams database, which contains approximately 7000 reservoirs that hold 77% of the total volume of water held back by dams (8000 km), it is estimated that the delivery of carbon to the ocean has decreased by 13% since 1970 and is projected to reach 19% by 2030. The excess carbon contained in the reservoirs may emit an additional ~0.184 Gt of carbon to the atmosphere per year and an additional ~0.2 GtC will be buried in sediment. Prior to 2000, the Mississippi, the Niger, and the Ganges River basins account for 25 – 31% of all reservoir carbon burial. After 2000, the Paraná (home to 70 dams) and the Zambezi (home to the largest reservoir) River basins exceeded the burial by the Mississippi. Other large contributors to carbon burial caused by damming occur on the Danube, the Amazon, the Yangtze, the Mekong, the Yenisei, and the Tocantins Rivers. | 0 | Theoretical and Fundamental Chemistry |
As higher amounts of alkali leach from the glass cracks are likely to become deeper. Crizzling is a distinctive network of fine cracks in the glass which is visible to the naked eye.
In some cases, the crazing can gain a more uniform appearance. However, crizzling may not be uniform due to the creation of micro-climates on the glass. | 0 | Theoretical and Fundamental Chemistry |
Cytochrome c is an essential component of the respiratory electron transport chain in mitochondria. The heme group of cytochrome c accepts electrons from the bc Complex III and transports them to Complex IV, while it transfers energy in the opposite direction.
Cytochrome c can also catalyze several redox reactions such as hydroxylation and aromatic oxidation, and shows peroxidase activity by oxidation of various electron donors such as 2,2-azino-bis(3-ethylbenzthiazoline-6-sulphonic acid) (ABTS), 2-keto-4-thiomethyl butyric acid and 4-aminoantipyrine.
A bacterial cytochrome c functions as a nitrite reductase. | 1 | Applied and Interdisciplinary Chemistry |
In a broad academic audience, the concept of the evolution of the genetic code from the original and ambiguous genetic code to a well-defined ("frozen") code with the repertoire of 20 (+2) canonical amino acids is widely accepted.
However, there are different opinions, concepts, approaches and ideas, which is the best way to change it experimentally. Even models are proposed that predict "entry points" for synthetic amino acid invasion of the genetic code.
Since 2001, 40 non-natural amino acids have been added into proteins by creating a unique codon (recoding) and a corresponding transfer-RNA:aminoacyl – tRNA-synthetase pair to encode it with diverse physicochemical and biological properties in order to be used as a tool to exploring protein structure and function or to create novel or enhanced proteins.
H. Murakami and M. Sisido extended some codons to have four and five bases. Steven A. Benner constructed a functional 65th (in vivo) codon.
In 2015 N. Budisa, D. Söll and co-workers reported the full substitution of all 20,899 tryptophan residues (UGG codons) with unnatural thienopyrrole-alanine in the genetic code of the bacterium Escherichia coli.
In 2016 the first stable semisynthetic organism was created. It was a (single cell) bacterium with two synthetic bases (called X and Y). The bases survived cell division.
In 2017, researchers in South Korea reported that they had engineered a mouse with an extended genetic code that can produce proteins with unnatural amino acids.
In May 2019, researchers reported the creation of a new "Syn61" strain of the bacterium Escherichia coli. This strain has a fully synthetic genome that is refactored (all overlaps expanded), recoded (removing the use of three out of 64 codons completely), and further modified to remove the now unnecessary tRNAs and release factors. It is fully viable and grows 1.6× slower than its wild-type counterpart "MDS42". | 1 | Applied and Interdisciplinary Chemistry |
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