text stringlengths 105 4.57k | label int64 0 1 | label_text stringclasses 2
values |
|---|---|---|
The isolation of trimyristin from powdered nutmeg is a common introductory-level college organic chemistry experiment. It is an uncommonly simple natural product extraction because nutmeg oil generally consists of over eighty percent trimyristin. Trimyristin makes up between 20-25% of the overall mass of dried, ground nutmeg. Separation is generally carried out by steam distillation and purification uses extraction from ether followed by distillation or rotary evaporation to remove the volatile solvent. The extraction of trimyristin can also be done with diethyl ether at room temperature, due to its high solubility in the ether. The experiment is frequently included in curricula, both for its relative ease and to provide instruction in these techniques. Trimyristin can then be used to prepare myristic acid or one of its salts as an example of saponification. | 1 | Applied and Interdisciplinary Chemistry |
Structural differences between capsaicin and members of the capsinoid family of compounds are illustrated below. Capsinoids have an ester bond in their structures, as compared with the amide bond characteristic of capsaicin. | 1 | Applied and Interdisciplinary Chemistry |
While river engineering can improve the behaviour of the river or hold it back to adapt to our infrastructure, and therefore be rated as positive or negative impact, pollution undoubtedly has a negative impact on our environment. The consequences are very complex and difficult to measure and classify, as often benefits for humankind imply drawbacks for the environment and the other way around. | 1 | Applied and Interdisciplinary Chemistry |
In organic chemistry, a bipolaron is a molecule or part of a macromolecular chain containing two positive charges in a conjugated system. The charges can be located in the centre of the chain or at its termini. Bipolarons and polarons are encountered in doped conducting polymers such as polythiophene.
It is possible to synthesize and isolate bipolaron model compounds for X-ray diffraction studies. The diamagnetic bis(triaryl)amine dication 2 in scheme 1 is prepared from the neutral precursor 1 in dichloromethane by reaction with 4 equivalents of antimony pentachloride. Two resonance structures exist for the dication. Structure 2a is a (singlet) diradical and 2b is the closed shell quinoid. The experimental bond lengths for the central vinylidene group in 2 are 141 pm and 137 pm compared to 144 pm and 134 pm for the precursor 1 implying some contribution from the quinoid structure.
On the other hand, when a thiophene unit is added to the core in the structure depicted in scheme 2, these bond lengths are identical (around 138 pm) making it a true hybrid. | 0 | Theoretical and Fundamental Chemistry |
In nuclear polyadenylation, a poly(A) tail is added to an RNA at the end of transcription. On mRNAs, the poly(A) tail protects the mRNA molecule from enzymatic degradation in the cytoplasm and aids in transcription termination, export of the mRNA from the nucleus, and translation. Almost all eukaryotic mRNAs are polyadenylated, with the exception of animal replication-dependent histone mRNAs. These are the only mRNAs in eukaryotes that lack a poly(A) tail, ending instead in a stem-loop structure followed by a purine-rich sequence, termed histone downstream element, that directs where the RNA is cut so that the 3′ end of the histone mRNA is formed.
Many eukaryotic non-coding RNAs are always polyadenylated at the end of transcription. There are small RNAs where the poly(A) tail is seen only in intermediary forms and not in the mature RNA as the ends are removed during processing, the notable ones being microRNAs. But, for many long noncoding RNAs – a seemingly large group of regulatory RNAs that, for example, includes the RNA Xist, which mediates X chromosome inactivation – a poly(A) tail is part of the mature RNA. | 1 | Applied and Interdisciplinary Chemistry |
# Cells must identify and be near each other.
# Hemifusion occurs.
# Fusion pore in hemifusion structure opens, thus allowing for cell contents to merge.
# Cells completely join from pore expansion. | 1 | Applied and Interdisciplinary Chemistry |
As with other cycloaddition reactions of a 1,3-dipole with a π-system, 1,3-dipolar cycloaddition using an azomethine ylide is a six-electron process. According to the Woodward–Hoffmann rules, this addition is suprafacial with respect to both the dipole and dipolarophile. The reaction is generally viewed as concerted, in which the two carbon-carbon bonds are being formed at the same time, but asynchronously. However, depending on the nature of the dipole and dipolarophile, diradical or zwitterionic intermediates are possible. The endo product is generally favored, as in the isoelectronic Diels–Alder reaction. In these reactions, the azomethine ylide is typically the HOMO, and the electron-deficient dipolarophile the LUMO, although cycloaddition reactions with unactivated π-systems are known to occur, especially when the cyclization is intramolecular. For a discussion of frontier molecular orbital theory of 1,3-dipolar cycloadditions, see 1,3-dipolar cycloaddition#Frontier molecular orbital theory.
1,3-Dipolar cycloaddition reactions of azomethine ylides commonly use alkenes or alkynes as dipolarophiles, to form pyrrolidines or pyrrolines, respectively. A reaction of an azomethine ylide with an alkene is shown above, and results in a pyrrolidine. This kind of reactions can be used to synthesis Ullazine. While dipolarophiles are typically α,β-unsaturated carbonyl compounds, there have been many recent advances in developing new types of dipolarophiles.
When the dipole and dipolarophile are part of the same molecule, an intramolecular cyclization reaction can lead to a polycyclic product of considerable complexity. If the dipolarophile is tethered to a carbon of the dipole, a fused bicycle is formed. If it is tethered to the nitrogen, a bridged structure results. The intramolecular nature of the reaction can also be useful in that regioselectivity is often constrained. Another advantage to intramolecular reactions is that the dipolarophile need not be electron-deficient—many examples of cyclization reactions with electron-rich, alkyl-substituted dipolarophiles have been reported, including the synthesis of martinellic acid shown below. | 0 | Theoretical and Fundamental Chemistry |
Variational transition-state theory is a refinement of transition-state theory. When using transition-state theory to estimate a chemical reaction rate, the dividing surface is taken to be a surface that intersects a first-order saddle point and is also perpendicular to the reaction coordinate in all other dimensions. When using variational transition-state theory, the position of the dividing surface between reactant and product regions is variationally optimized to minimize the reaction rate. This minimizes the effects of recrossing, and gives a much more accurate result. | 0 | Theoretical and Fundamental Chemistry |
Tin-lead (Sn-Pb) solders, also called soft solders, are commercially available with tin concentrations between 5% and 70% by weight. The greater the tin concentration, the greater the solder's tensile and shear strengths. Lead mitigates the formation of tin whiskers, though the precise mechanism for this is unknown. Today, many techniques are used to mitigate the problem, including changes to the annealing process (heating and cooling), addition of elements like copper and nickel, and the application of conformal coatings. Alloys commonly used for electrical soldering are 60/40 Sn-Pb, which melts at , and 63/37 Sn-Pb used principally in electrical/electronic work. The latter mixture is a eutectic alloy of these metals, which:
# has the lowest melting point () of all the tin-lead alloys; and
# the melting point is truly a point — not a range.
In the United States, since 1974, lead is prohibited in solder and flux in plumbing applications for drinking water use, per the Safe Drinking Water Act. Historically, a higher proportion of lead was used, commonly 50/50. This had the advantage of making the alloy solidify more slowly. With the pipes being physically fitted together before soldering, the solder could be wiped over the joint to ensure water tightness. Although lead water pipes were displaced by copper when the significance of lead poisoning began to be fully appreciated, lead solder was still used until the 1980s because it was thought that the amount of lead that could leach into water from the solder was negligible from a properly soldered joint. The electrochemical couple of copper and lead promotes corrosion of the lead and tin. Tin, however, is protected by insoluble oxide. Since even small amounts of lead have been found detrimental to health as a potent neurotoxin, lead in plumbing solder was replaced by silver (food-grade applications) or antimony, with copper often added, and the proportion of tin was increased (see lead-free solder).
The addition of tin—more expensive than lead—improves wetting properties of the alloy; lead itself has poor wetting characteristics. High-tin tin-lead alloys have limited use as the workability range can be provided by a cheaper high-lead alloy.
Lead-tin solders readily dissolve gold plating and form brittle intermetallics.
60/40 Sn-Pb solder oxidizes on the surface, forming a complex 4-layer structure: tin(IV) oxide on the surface, below it a layer of tin(II) oxide with finely dispersed lead, followed by a layer of tin(II) oxide with finely dispersed tin and lead, and the solder alloy itself underneath.
Lead, and to some degree tin, as used in solder contains small but significant amounts of radioisotope impurities. Radioisotopes undergoing alpha decay are a concern due to their tendency to cause soft errors. Polonium-210 is especially troublesome; lead-210 beta decays to bismuth-210 which then beta decays to polonium-210, an intense emitter of alpha particles. Uranium-238 and thorium-232 are other significant contaminants of alloys of lead. | 1 | Applied and Interdisciplinary Chemistry |
Armstrong's acid (naphthalene-1,5-disulfonic acid) is a fluorescent organic compound with the formula CH(SOH). It is one of several isomers of naphthalenedisulfonic acid. It a colorless solid, typically obtained as the tetrahydrate. Like other sulfonic acids, it is a strong acid. It is named for British chemist Henry Edward Armstrong. | 0 | Theoretical and Fundamental Chemistry |
Henry Cavendish was born on 10 October 1731 in Nice, where his family was living at the time. His mother was Lady Anne de Grey, fourth daughter of Henry Grey, 1st Duke of Kent, and his father was Lord Charles Cavendish, the third son of William Cavendish, 2nd Duke of Devonshire. The family traced its lineage across eight centuries to Norman times, and was closely connected to many aristocratic families of Great Britain. Henrys mother died in 1733, three months after the birth of her second son, Frederick, and shortly before Henrys second birthday, leaving Lord Charles Cavendish to bring up his two sons. Henry Cavendish was styled as "The Honourable Henry Cavendish".
From the age of 11 Henry attended Newcomes School, a private school near London. At the age of 18 (on 24 November 1748) he entered the University of Cambridge in St Peters College, now known as Peterhouse, but left three years later on 23 February 1751 without taking a degree (at the time, a common practice). He then lived with his father in London, where he soon had his own laboratory.
Lord Charles Cavendish spent his life firstly in politics and then increasingly in science, especially in the Royal Society of London. In 1758, he took Henry to meetings of the Royal Society and also to dinners of the Royal Society Club. In 1760, Henry Cavendish was elected to both these groups, and he was assiduous in his attendance after that. He took virtually no part in politics, but followed his father into science, through his researches and his participation in scientific organisations. He was active in the Council of the Royal Society of London (to which he was elected in 1765).
His interest and expertise in the use of scientific instruments led him to head a committee to review the Royal Societys meteorological instruments and to help assess the instruments of the Royal Greenwich Observatory. His first paper, Factitious Airs, appeared in 1766. Other committees on which he served included the committee of papers, which chose the papers for publication in the Philosophical Transactions of the Royal Society, and the committees for the transit of Venus (1769), for the gravitational attraction of mountains (1774), and for the scientific instructions for Constantine Phippss expedition (1773) in search of the North Pole and the Northwest Passage. In 1773, Henry joined his father as an elected trustee of the British Museum, to which he devoted a good deal of time and effort. Soon after the Royal Institution of Great Britain was established, Cavendish became a manager (1800) and took an active interest, especially in the laboratory, where he observed and helped in Humphry Davy's chemical experiments. | 1 | Applied and Interdisciplinary Chemistry |
Annals of Clinical Biochemistry is a bimonthly peer-reviewed scientific journal covering all aspects of clinical biochemistry. The editor-in-chief is Michael J Murphy (University of Dundee). It was established 1960 and is published by SAGE Publications on behalf of The Association for Clinical Biochemistry and Laboratory Medicine. | 1 | Applied and Interdisciplinary Chemistry |
Tramadol is metabolised in the liver via the cytochrome P450 isozyme CYP2B6, CYP2D6, and CYP3A4, being O- and N-demethylated to five different metabolites. Of these, desmetramadol (O-desmethyltramadol) is the most significant, since it has 200 times the μ-affinity of (+)-tramadol, and furthermore has an elimination half-life of 9 hours, compared with 6 hours for tramadol itself. As with codeine, in the 6% of the population who have reduced CYP2D6 activity (hence reducing metabolism), a reduced analgesic effect is seen. Those with decreased CYP2D6 activity require a dose increase of 30% to achieve the same degree of pain relief as those with a normal level of CYP2D6 activity.
Phase II hepatic metabolism renders the metabolites water-soluble, which are excreted by the kidneys. Thus, reduced doses may be used in renal and hepatic impairment.
Its volume of distribution is around 306 L after oral administration and 203 L after parenteral administration. | 0 | Theoretical and Fundamental Chemistry |
In plasmas and electrolytes, the Debye length (Debye radius or Debye–Hückel screening length), is a measure of a charge carrier's net electrostatic effect in a solution and how far its electrostatic effect persists. With each Debye length the charges are increasingly electrically screened and the electric potential decreases in magnitude by 1/e. A Debye sphere is a volume whose radius is the Debye length. Debye length is an important parameter in plasma physics, electrolytes, and colloids (DLVO theory). The corresponding Debye screening wave vector for particles of density , charge at a temperature is given by in Gaussian units. Expressions in MKS units will be given below. The analogous quantities at very low temperatures () are known as the Thomas–Fermi length and the Thomas–Fermi wave vector. They are of interest in describing the behaviour of electrons in metals at room temperature.
The Debye length is named after the Dutch-American physicist and chemist Peter Debye (1884-1966), a Nobel laureate in Chemistry. | 0 | Theoretical and Fundamental Chemistry |
Xylenes are used as a solvent in printing, rubber, and leather industries. It is a common component of ink, rubber, and adhesives. In thinning paints and varnishes, it can be substituted for toluene where slower drying is desired, and thus is used by conservators of art objects in solubility testing. Similarly it is a cleaning agent, e.g., for steel, silicon wafers, and integrated circuits. In dentistry, xylene can be used to dissolve gutta percha, a material used for endodontics (root-canal treatments). In the petroleum industry, xylene is also a frequent component of paraffin solvents, used when the tubing becomes clogged with paraffin wax. | 1 | Applied and Interdisciplinary Chemistry |
Multiplex polymerase chain reaction (Multiplex PCR) refers to the use of polymerase chain reaction to amplify several different DNA sequences simultaneously (as if performing many separate PCR reactions all together in one reaction). This process amplifies DNA in samples using multiple primers and a temperature-mediated DNA polymerase in a thermal cycler. The primer design for all primers pairs has to be optimized so that all primer pairs can work at the same annealing temperature during PCR.
Multiplex-PCR was first described in 1988 as a method to detect deletions in the dystrophin gene. It has also been used with the steroid sulfatase gene. In 2008, multiplex-PCR was used for analysis of microsatellites and SNPs. In 2020, RT-PCR multiplex assays were designed that combined multiple gene targets from the Center for Diseases and Control in a single reaction to increase molecular testing accessibility and throughput for SARS-CoV-2 diagnostics.
Multiplex-PCR consists of multiple primer sets within a single PCR mixture to produce amplicons of varying sizes that are specific to different DNA sequences. By targeting multiple sequences at once, additional information may be gained from a single test run that otherwise would require several times the reagents and more time to perform. Annealing temperatures for each of the primer sets must be optimized to work correctly within a single reaction, and amplicon sizes, i.e., their base pair length, should be different enough to form distinct bands when visualized by gel electrophoresis. Alternatively, if amplicon sizes overlap, the different amplicons may be differentiated and visualised using primers that have been dyed with different colour fluorescent dyes. Commercial multiplexing kits for PCR are available and used by many forensic laboratories to amplify degraded DNA samples. | 1 | Applied and Interdisciplinary Chemistry |
The cosmic microwave background contains a small linearly-polarized component attributed to Thomson scattering. That polarized component mapping out the so-called E-modes was first detected by DASI in 2002.
The solar K-corona is the result of the Thomson scattering of solar radiation from solar coronal electrons. The ESA and NASA SOHO mission and the NASA STEREO mission generate three-dimensional images of the electron density around the Sun by measuring this K-corona from three separate satellites.
In tokamaks, corona of ICF targets and other experimental fusion devices, the electron temperatures and densities in the plasma can be measured with high accuracy by detecting the effect of Thomson scattering of a high-intensity laser beam. An upgraded Thomson scattering system in the Wendelstein 7-X stellarator uses Nd:YAG lasers to emit multiple pulses in quick succession. The intervals within each burst can range from 2 ms to 33.3 ms, permitting up to twelve consecutive measurements. Synchronization with plasma events is made possible by a newly added trigger system that facilitates real-time analysis of transient plasma events.
In the Sunyaev–Zeldovich effect, where the photon energy is much less than the electron rest mass, the inverse-Compton scattering can be approximated as Thomson scattering in the rest frame of the electron.
Models for X-ray crystallography are based on Thomson scattering. | 0 | Theoretical and Fundamental Chemistry |
If there are diffusing particles with different sizes (diffusion coefficients), it is common to fit to a function that is the sum of single component forms:
where the sum is over the number different sizes of particle, indexed by i, and gives the weighting, which is related to the quantum yield and concentration of each type. This introduces new parameters, which makes the fitting more difficult as a higher-dimensional space must be searched. Nonlinear least square fitting typically becomes unstable with even a small number of s. A more robust fitting scheme, especially useful for polydisperse samples, is the Maximum Entropy Method. | 0 | Theoretical and Fundamental Chemistry |
Relative rates of chemical reactions provide useful insights into the effects of the steric bulk of substituents. Under standard conditions, methyl bromide solvolyzes 10 faster than does neopentyl bromide. The difference reflects the inhibition of attack on the compound with the sterically bulky (CH)C group. | 0 | Theoretical and Fundamental Chemistry |
SELDI technology can potentially be used in any application by modifying the SELDI surface. SELDI-TOF-MS is optimal for analyzing low molecular weight proteins (<20 kDa) in a variety of biological materials, such as tissue samples, blood, urine, and serum. This technique is often used in combination with immunoblotting and immunohistochemistry as a diagnostic tool to aid in the detection of biomarkers for diseases, and has also been applied to the diagnosis of cancer and neurological disorders. SELDI-TOF-MS has been used in biomarker discovery for lung, breast, liver, colon, pancreatic, bladder, kidney, cervical, ovarian, and prostate cancers. SELDI technology is most widely used in biomarker discovery to compare protein levels in serum samples from healthy and diseased patients. Serum studies allow for a minimally invasive approach to disease monitoring in patients and are useful in the early detection and diagnosis of diseases and neurological disorders, such as amyotrophic lateral sclerosis (ALS) and Alzheimer's.
SELDI-TOF-MS can also be used in biological applications to detect post-translationally modified proteins and to study phosphorylation states of proteins. | 1 | Applied and Interdisciplinary Chemistry |
The two basic methods of NMR analysis are single- and double-derivatization. Double-derivatization is generally considered more accurate, but single-derivatization usually requires less reagents and, thus, is more cost effective. | 0 | Theoretical and Fundamental Chemistry |
Refining is the removal of impurities from materials by a thermal process. This covers a wide range of processes, involving different kinds of furnace or other plant.
The term "refining" can also refer to certain electrolytic processes. Accordingly, some kinds of pyrometallurgical refining are referred to as "fire refining". | 1 | Applied and Interdisciplinary Chemistry |
The GUS system is not the only available gene reporter system for the analysis of promoter activity. Other competing systems are based on e.g. luciferase, GFP, beta-galactosidase, chloramphenicol acetyltransferase (CAT), alkaline phosphatase. The use of one or the other system is mainly dependent on the organism of interest and the imaging and microscopy technologies available to the laboratories conducting the research. | 1 | Applied and Interdisciplinary Chemistry |
A depletion force is an effective attractive force that arises between large colloidal particles that are suspended in a dilute solution of depletants, which are smaller solutes that are preferentially excluded from the vicinity of the large particles. One of the earliest reports of depletion forces that lead to particle coagulation is that of Bondy, who observed the separation or "creaming" of rubber latex upon addition of polymer depletant molecules (sodium alginate) to solution. More generally, depletants can include polymers, micelles, osmolytes, ink, mud, or paint dispersed in a continuous phase.
Depletion forces are often regarded as entropic forces, as was first explained by the established Asakura–Oosawa model. In this theory the depletion force arises from an increase in osmotic pressure of the surrounding solution when colloidal particles get close enough such that the excluded cosolutes (depletants) cannot fit in between them.
Because the particles were considered as hard-core (completely rigid) particles, the emerging picture of the underlying mechanism inducing the force was necessarily entropic. | 0 | Theoretical and Fundamental Chemistry |
CDP's funding comes from a combination of government and philanthropic grants (44.4%) and a mixture of membership fees, administrative fees, sponsorships and data licensing. In Europe, CDP is around 30% funded by the LIFE programme of the European Commission. | 1 | Applied and Interdisciplinary Chemistry |
The indexing results are used to generate a map of the crystallographic orientation at each point on the surface being studied. Thus, scanning the electron beam in a prescribed fashion (typically in a square or hexagonal grid, correcting for the image foreshortening due to the sample tilt) results in many rich microstructural maps. These maps can spatially describe the crystal orientation of the material being interrogated and can be used to examine microtexture and sample morphology. Some maps describe grain orientation, boundary, and diffraction pattern (image) quality. Various statistical tools can measure the average misorientation, grain size, and crystallographic texture. From this dataset, numerous maps, charts and plots can be generated. The orientation data can be visualised using a variety of techniques, including colour-coding, contour lines, and pole figures.
Microscope misalignment, image shift, scan distortion that increases with decreasing magnification, roughness and contamination of the specimen surface, boundary indexing failure and detector quality can lead to uncertainties in determining the crystal orientation. The EBSD signal-to-noise ratio depends on the material and decreases at excessive acquisition speed and beam current, thereby affecting the angular resolution of the measurement. | 0 | Theoretical and Fundamental Chemistry |
Mutacin 1140 is a bacteriocin produced by Streptococcus mutans. It has activity against a broad spectrum of Gram-positive bacteria. It is a member of the class of compounds known as lantibiotics.
Mutacin 1140 belongs to the epidermin subset of type Al lantibiotics. Molecules belonging to this family bind to lipid II which is a precursor to bacterial cell wall synthesis.
While the effects mutacin 1140 has against gram-positive bacteria are known, it remains difficult to study due to it demonstrating poor pharmacokinetics. Besides the poor pharmacokinetics, it is easily vulnerable to proteolytic degradation by interfering with the protein's peptide bonds. | 1 | Applied and Interdisciplinary Chemistry |
In obstructive jaundice, no bilirubin reaches the small intestine, meaning that there is no formation of stercobilinogen. The lack of stercobilin and other bile pigments causes feces to become clay-colored. | 1 | Applied and Interdisciplinary Chemistry |
The most common dye used to make DNA or RNA bands visible for agarose gel electrophoresis is ethidium bromide, usually abbreviated as EtBr. It fluoresces under UV light when intercalated into the major groove of DNA (or RNA). By running DNA through an EtBr-treated gel and visualizing it with UV light, any band containing more than ~20 ng DNA becomes distinctly visible. EtBr is a known mutagen, and safer alternatives are available, such as GelRed, produced by Biotium, which binds to the minor groove.
SYBR Green I is another dsDNA stain, produced by Invitrogen. It is more expensive, but 25 times more sensitive, and possibly safer than EtBr, though there is no data addressing its mutagenicity or toxicity in humans.
SYBR Safe is a variant of SYBR Green that has been shown to have low enough levels of mutagenicity and toxicity to be deemed nonhazardous waste under U.S. Federal regulations. It has similar sensitivity levels to EtBr, but, like SYBR Green, is significantly more expensive. In countries where safe disposal of hazardous waste is mandatory, the costs of EtBr disposal can easily outstrip the initial price difference, however.
Since EtBr stained DNA is not visible in natural light, scientists mix DNA with negatively charged loading buffers before adding the mixture to the gel. Loading buffers are useful because they are visible in natural light (as opposed to UV light for EtBr stained DNA), and they co-sediment with DNA (meaning they move at the same speed as DNA of a certain length). Xylene cyanol and Bromophenol blue are common dyes found in loading buffers; they run about the same speed as DNA fragments that are 5000 bp and 300 bp in length respectively, but the precise position varies with percentage of the gel. Other less frequently used progress markers are Cresol Red and Orange G which run at about 125 bp and 50 bp, respectively.
Visualization can also be achieved by transferring DNA after SDS-PAGE to a nitrocellulose membrane followed by exposure to a hybridization probe. This process is termed Southern blotting.
For fluorescent dyes, after electrophoresis the gel is illuminated with an ultraviolet lamp (usually by placing it on a light box, while using protective gear to limit exposure to ultraviolet radiation). The illuminator apparatus mostly also contains imaging apparatus that takes an image of the gel, after illumination with UV radiation. The ethidium bromide fluoresces reddish-orange in the presence of DNA, since it has intercalated with the DNA. The DNA band can also be cut out of the gel, and can then be dissolved to retrieve the purified DNA.
The gel can then be photographed usually with a digital or polaroid camera. Although the stained nucleic acid fluoresces reddish-orange, images are usually shown in black and white (see figures). UV damage to the DNA sample can reduce the efficiency of subsequent manipulation of the sample, such as ligation and cloning. Shorter wavelength UV radiations (302 or 312 nm) cause greater damage, for example exposure for as little as 45 seconds can significantly reduce transformation efficiency. Therefore if the DNA is to be use for downstream procedures, exposure to a shorter wavelength UV radiations should be limited, instead higher-wavelength UV radiation (365 nm) which cause less damage should be used. Higher wavelength radiations however produces weaker fluorescence, therefore if it is necessary to capture the gel image, a shorter wavelength UV light can be used a short time. Addition of Cytidine or guanosine to the electrophoresis buffer at 1 mM concentration may protect the DNA from damage. Alternatively, a blue light excitation source with a blue-excitable stain such as SYBR Green or GelGreen may be used.
Gel electrophoresis research often takes advantage of software-based image analysis tools, such as ImageJ. | 1 | Applied and Interdisciplinary Chemistry |
Since tritium is a low energy beta emitter, it is not dangerous externally (its beta particles are unable to penetrate the skin), but it can be a radiation hazard if inhaled, ingested via food or water, or absorbed through the skin.
Organisms can take up HTO, as they would H2O. Plants convert HTO into organically bound tritium (OBT), and are consumed by animals. HTO is retained in humans for around 12 days, with a small portion of it remaining in the body. Tritium can be passed along the food chain as one organism feeds on another, although the metabolism of OBT is less understood than that of HTO. Tritium can incorporate to RNA and DNA molecules within organisms which can lead to somatic and genetic impacts. These can emerge in subsequent generations.
HTO has a short biological half-life in the human body of 7 to 14 days, which both reduces the total effects of single-incident ingestion and precludes long-term bioaccumulation of HTO from the environment. The biological half life of tritiated water in the human body, which is a measure of body water turn-over, varies with the season. Studies on the biological half life of occupational radiation workers for free water tritium in a coastal region of Karnataka, India, show that the biological half life in the winter season is twice that of the summer season. If tritium exposure is suspected or known, drinking uncontaminated water will help replace the tritium from the body. Increasing sweating, urination or breathing can help the body expel water and thereby the tritium contained in it. However, care should be taken that neither dehydration nor a depletion of the body's electrolytes results, as the health consequences of those things (particularly in the short term) can be more severe than those of tritium exposure. | 0 | Theoretical and Fundamental Chemistry |
Nuclear medicine or nucleology is a medical specialty involving the application of radioactive substances in the diagnosis and treatment of disease. Nuclear imaging, in a sense, is "radiology done inside out" because it records radiation emitted from within the body rather than radiation that is transmitted through the body from external sources like X-ray generators. In addition, nuclear medicine scans differ from radiology, as the emphasis is not on imaging anatomy, but on the function. For such reason, it is called a physiological imaging modality. Single photon emission computed tomography (SPECT) and positron emission tomography (PET) scans are the two most common imaging modalities in nuclear medicine. | 1 | Applied and Interdisciplinary Chemistry |
Despite the many millions of dollars spent by the U.S. between 1952 and 1992 to produce a pure fusion weapon, no measurable success was ever achieved. In 1998, the U.S. Department of Energy (DOE) released a restricted data declassification decision stating that even if the DOE made a substantial investment in the past to develop a pure fusion weapon, "the U.S. is not known to have and is not developing a pure fusion weapon and no credible design for a pure fusion weapon resulted from the DOE investment". The power densities needed to ignite a fusion reaction still seem attainable only with the aid of a fission explosion, or with large apparatus such as powerful lasers like those at the National Ignition Facility, the Sandia Z-pinch machine, or various magnetic tokamaks. Regardless of any claimed advantages of pure fusion weapons, building those weapons does not appear to be feasible using currently available technologies and many have expressed concern that pure fusion weapons research and development would subvert the intent of the Nuclear Non-Proliferation Treaty and the Comprehensive Test Ban Treaty.
It has been claimed that it is possible to conceive of a crude, deliverable, pure fusion weapon, using only present-day, unclassified technology. The weapon design weighs approximately 3 tonnes, and might have a total yield of approximately 3 tonnes of TNT. The proposed design uses a large explosively pumped flux compression generator to produce the high power density required to ignite the fusion fuel. From the point of view of explosive damage, such a weapon would have no clear advantages over a conventional explosive, but the massive neutron flux could deliver a lethal dose of radiation to humans within a 500-meter radius (most of those fatalities would occur over a period of months, rather than immediately). | 0 | Theoretical and Fundamental Chemistry |
For some applications, the initial momentum distribution of emitted electrons is important and the mean transverse energy (MTE) and thermal emittance are popular metrics for this. The MTE is the mean of the squared momentum in a direction along the photocathode's surface and is most commonly reported in units of milli-electron volts.
In high brightness photoinjectors, the MTE helps to determine the initial emittance of the beam which is the area in phase space occupied by the electrons. The emittance () can be calculated from MTE and the laser spot size on the photocathode () using the following equation.
where is the rest mass of an electron. In commonly used units, this is as follows.
Because of the scaling of transverse emittance with MTE, it is sometimes useful to write the equation in terms of a new quantity called the thermal emittance. The thermal emittance is derived from MTE using the following equation.
It is most often expressed in the ratio um/mm to express the growth of emittance in units of um as the laser spot grows (measured in units of mm).
An equivalent definition of MTE is the temperature of electrons emitted in vacuum. The MTE of electrons emitted from commonly used photocathodes, such as polycrystalline metals, is limited by the excess energy (the difference between the energy of the incident photons and the photocathode's work function) provided to the electrons. To limit MTE, photocathodes are often operated near the photoemission threshold, where the excess energy tends to zero. In this limit, the majority of photoemission comes from the tail of the Fermi distribution. Therefore, MTE is thermally limited to , where is the Boltzmann constant and is the temperature of electrons in the solid.
Due to conservation of transverse momentum and energy in the photoemission process, the MTE of a clean, atomically-ordered, single crystalline photocathode is determined by the material's band structure. An ideal band structure for low MTEs is one that does not allow photoemission from large transverse momentum states.
Outside of accelerator physics, MTE and thermal emittance play a role in the resolution of proximity-focused imaging devices that use photocathodes. This is important for applications such as image intensifiers, wavelength converters, and the now obsolete image tubes. | 0 | Theoretical and Fundamental Chemistry |
* All alcoholic drinks including beer, cider, kombucha, kvass, mead, perry, tibicos, wine, pulque, hard liquors (brandy, rum, vodka, sake, schnapps), and soured by-products including vinegar and alegar
* Yeast leavened breads including sourdough, salt-rising bread, and others
* Cheese and some dairy products including kefir and yogurt
* Chocolate
* Coffee
* Dishes including fermented fish, such as garum, surströmming, and Worcestershire sauce
* Some vegetables such as kimchi, some types of pickles (most are not fermented though), and sauerkraut
* A wide variety of fermented foods made from soybeans, including fermented bean paste, nattō, tempeh, and soya sauce | 1 | Applied and Interdisciplinary Chemistry |
NPP belongs to the alkaline phosphatase superfamily, which is a group of evolutionarily related enzymes that catalyze phosphoryl and sulfuryl transfer reactions. This group includes phosphomonoesterases, phosphodiesterases, phosphoglycerate mutases, phosphophenomutases, and sulfatases. | 1 | Applied and Interdisciplinary Chemistry |
The Canadian Food Inspection Agency restricts the use of "natural" to foods that have not been significantly altered by processing and gives examples of processes that do or do not significantly alter food. This includes two specific additional requirements:
*A natural food or ingredient of a food is not expected to contain, or ever to have contained, an added vitamin, mineral nutrient, artificial flavoring agent or food additive.
*A natural food or ingredient of a food does not have any constituent or fraction thereof removed or significantly changed, except the removal of water. | 1 | Applied and Interdisciplinary Chemistry |
To maintain indoor air quality, it may be desirable to expunge return air from the conditioned space and replace it with fresh outdoor air, sometimes called "make-up air." The optimal location to expunge return air from a Cromer cycle system is just after the desiccant (location 2 on Figure 1). At this point, the return air has been loaded with moisture from the desiccant, and expunging it removes additional moisture from the space. Furthermore, this expunge air is cooled below the return air condition by the desiccant's evaporation of the moisture into it. Location 2 (but before the fan) is also the ideal place to bring outdoor air into the system, as the coil can then reduce its temperature and moisture before it enters the space. Also, if heat exchange is provided between the expunged air and the outdoor air, the incoming air can be cooled and brought near to or at saturation before it enters the cooling coil for process 2 to 3, enhancing its dehumidification. | 0 | Theoretical and Fundamental Chemistry |
The two-step conversion of ammonia to nitrate observed in ammonia-oxidizing bacteria, ammonia-oxidizing archaea and nitrite-oxidizing bacteria (such as Nitrobacter) is puzzling to researchers. Complete nitrification, the conversion of ammonia to nitrate in a single step known as comammox, has an energy yield (∆G°′) of −349 kJ mol NH, while the energy yields for the ammonia-oxidation and nitrite-oxidation steps of the observed two-step reaction are −275 kJ mol NH, and −74 kJ mol NO, respectively. These values indicate that it would be energetically favourable for an organism to carry out complete nitrification from ammonia to nitrate (comammox), rather than conduct only one of the two steps. The evolutionary motivation for a decoupled, two-step nitrification reaction is an area of ongoing research. In 2015, it was discovered that the species Nitrospira inopinata possesses all the enzymes required for carrying out complete nitrification in one step, suggesting that this reaction does occur. | 1 | Applied and Interdisciplinary Chemistry |
The Dhar iron pillar is a now-fragmented iron column located in the Dhar town of Madhya Pradesh, India. The exact origins of the pillar are unknown, but according to the local tradition, it was a victory column erected by the 11th century Paramara king Bhoja.
Three of its fragments are now located near the 15th century Lat Masjid ("pillar mosque"), which is named after the pillar (called "lāṭ" in Hindi). A fourth portion is believed to be missing. The original pillar tapered from bottom to top: the bottom fragment has a square cross-section; the middle fragment has square and octagonal cross-sections, and the top fragment has an octagonal cross-section with a small circular part at the end. The total length of the three fragments is , which indicates that the original pillar must have been twice as high as the iron pillar of Delhi. The combined weight of the fragments is estimated at around , which is at least more than the Delhi pillar's weight. At the time of its erection, it was probably the largest forge-welded iron pillar in the world. | 1 | Applied and Interdisciplinary Chemistry |
A blacklight, also called a UV-A light, Wood's lamp, or ultraviolet light, is a lamp that emits long-wave (UV-A) ultraviolet light and very little visible light. One type of lamp has a violet filter material, either on the bulb or in a separate glass filter in the lamp housing, which blocks most visible light and allows through UV, so the lamp has a dim violet glow when operating. Blacklight lamps which have this filter have a lighting industry designation that includes the letters "BLB". This stands for "blacklight blue". A second type of lamp produces ultraviolet but does not have the filter material, so it produces more visible light and has a blue color when operating. These tubes are made for use in "bug zapper" insect traps, and are identified by the industry designation "BL". This stands for "blacklight".
Blacklight sources may be specially designed fluorescent lamps, mercury-vapor lamps, light-emitting diodes (LEDs), lasers, or incandescent lamps. In medicine, forensics, and some other scientific fields, such a light source is referred to as a Woods lamp, named after Robert Williams Wood, who invented the original Woods glass UV filters.
Although many other types of lamp emit ultraviolet light with visible light, black lights are essential when UV-A light without visible light is needed, particularly in observing fluorescence, the colored glow that many substances emit when exposed to UV. Black lights are employed for decorative and artistic lighting effects, diagnostic and therapeutic uses in medicine, the detection of substances tagged with fluorescent dyes, rock-hunting, scorpion-hunting, the detection of counterfeit money, the curing of plastic resins, attracting insects and the detection of refrigerant leaks affecting refrigerators and air conditioning systems. Strong sources of long-wave ultraviolet light are used in tanning beds. | 0 | Theoretical and Fundamental Chemistry |
Metallurgy only appears in Mesoamerica in 800 CE with the best evidence from West Mexico. Much like in South America, fine metals were seen as a material for the elite. Metal's special qualities of colour and resonance seemed to have appealed most and then led to the particular technological developments seen in the region.
Exchange of ideas and goods with peoples from the Ecuador and Colombia region (likely via a maritime route) seems to have fueled early interest and development. Similar metal artifact types are found in West Mexico and the two regions: copper rings, needles, and tweezers being fabricated in the same ways as in Ecuador and also found in similar archaeological contexts. A multitude of bells were also found, but in this case they were cast using the same lost-wax casting method as seen in Colombia. During this period, copper was being used almost exclusively.
Continual contact kept the flow of ideas from that same region and later, coinciding with the development of Andean long distance maritime trade, influence from further south seems to have reached the region and led to a second period (1200–1300 CE to the Spanish arrival). By this time, copper alloys were being explored by West Mexican metallurgists, partly because the different mechanical properties were needed to fashion specific artifacts, particularly axe-monies – further evidence for contact with the Andean region. However, in general the new properties such alloys introduced were developed to meet regional needs, especially wirework bells, which at times had such high tin content in the bronze that it was irrelevant for its mechanical properties but gave the bells a golden colour.
The actual artifacts and then techniques were imported from the south, but west Mexican metallurgists worked ores from the abundant local deposits; the metal was not being imported. Even when the technology spread from West into north-eastern, central and southern Mexico, artifacts that can be traced back to West Mexican ores are abundant, if not exclusive. It is not always clear if the metal reached its final destination as an ingot, an ore or a finished artifact. Provenance studies on metal artifacts from southern Mesoamerica cast with the lost wax technique and dissimilar to west Mexican artifacts have shown that there might have been a second point of emergence of metallurgy into Mesoamerica there since no known source could be identified.
In the Tarascan Empire, copper and bronze was used for chisels, punches, awls, tweezers, needles, axes, discs, and breastplates.
The Aztecs did not initially adopt metal working, even though they had acquired metal objects from other peoples. However, as conquest gained them metal working regions, the technology started to spread. By the time of the Spanish conquest, a bronze-smelting technology had already been developed. Spanish conquistadors used indigenous smelting technology to produce weapons and tools. | 1 | Applied and Interdisciplinary Chemistry |
Inulin is a naturally occurring polysaccharide complex carbohydrate composed of fructose, a plant-derived food that human digestive enzymes cannot completely break down. The inulins belong to a class of dietary fibers known as fructans. Inulin is used by some plants as a means of storing energy and is typically found in roots or rhizomes. Most plants that synthesize and store inulin do not store other forms of carbohydrates such as starch. In the United States in 2018, the Food and Drug Administration approved inulin as a dietary fiber ingredient used to improve the nutritional value of manufactured food products. | 0 | Theoretical and Fundamental Chemistry |
Ted Ellis maintained a passion for art that preceded his professional art career; he painted throughout his time in the Army and as an environmental chemist, generally working out of a studio in his garage. His first commissions were produced for two co-workers at Rollins. They had wanted to purchase the piece that he was then working on, but he refused and instead offered to paint them two similar pieces, which they purchased for $40.
When he first got started, Ellis passed on an opportunity to do work for the J. C. Penney catalog because he was too busy, but ultimately found success in a similar publication.
Ellis published his first prints through Market Arts Dan Rose in Houston, but his art career took off when he noticed that his wifes Avon boutique magazine, targeted at African-Americans, lacked any art. He sent Avon a proposal which they accepted, and through the magazine he sold 42,610 signed prints of Thee Baptism. Since he was still working as an engineer at the time, he autographed the tens-of-thousands of prints during his lunch-break.
After quitting his job as an engineer in 1996, Ellis competed against 500 others for, and won, a 1998 Walt Disney Studios commission for art in honor of Black History Month. The piece was used in the 1999 celebration at Epcot Center and appeared on T-shirts, souvenir-mugs, and posters. | 0 | Theoretical and Fundamental Chemistry |
In liquid crystals, homeotropic alignment is one of the ways of alignment of liquid crystalline molecules. Homeotropic alignment is the state in which a rod-like liquid crystalline molecule aligns perpendicularly to the substrate. In the polydomain state, the parts also are called homeotropic domains. In contrast, the state in which the molecule aligns to a substance in parallel is called homogeneous alignment.
There are various other ways of alignment in liquid crystals. Because homeotropic alignment is not anisotropic optically, a dark field is observed between crossed polarizers in polarizing optical microscopy.
By conoscope observation, however, a cross image is observed in the homeotropic alignments. Homeotropic alignment often appears in the smectic A phase (S).
In discotic liquid crystals homeotropic alignment is defined as the state in which an axis of the column structure, which is formed by disc-like liquid crystalline molecules, aligns perpendicularly to a substance. In other words, this alignment looks like a state in which columns formed by piled-up coins are arranged in an orderly way on a table.
In practice, the homeotropic alignment is usually achieved by surfactants and detergent for example lecithin, some esilanes or some special polyimide (PI 1211). Generally liquid crystals align homeotropically at an air or glass interface. | 0 | Theoretical and Fundamental Chemistry |
One of the major fields within pharmaceutical bioinformatics is the in silico metabolism prediction of drug candidates. This field is in turn divided into three tasks;
* Predicting the occurrence of an interaction between a compound and an enzyme,
* Predicting the location in the compound that takes part in the interaction, i.e. the site of metabolism (SOM),
* Predicting the outcome from the interaction, i.e. the resulting metabolite product.
There are several existing tools trying to solve these tasks, e.g. SMARTCyp and MetaPrint2D predicts the SOM for chemical compounds. | 1 | Applied and Interdisciplinary Chemistry |
N-Linked glycosylation involves oligosaccharide attachment to asparagine via a beta linkage to the amine nitrogen of the side chain. The process of N-linked glycosylation occurs cotranslationally, or concurrently while the proteins are being translated. Since it is added cotranslationally, it is believed that N-linked glycosylation helps determine the folding of polypeptides due to the hydrophilic nature of sugars. All N-linked oligosaccharides are pentasaccharides: five monosaccharides long.
In N-glycosylation for eukaryotes, the oligosaccharide substrate is assembled right at the membrane of the endoplasmatic reticulum. For prokaryotes, this process occurs at the plasma membrane. In both cases, the acceptor substrate is an asparagine residue. The asparagine residue linked to an N-linked oligosaccharide usually occurs in the sequence Asn-X-Ser/Thr, where X can be any amino acid except for proline, although it is rare to see Asp, Glu, Leu, or Trp in this position. | 0 | Theoretical and Fundamental Chemistry |
The fluorinated surfactants or fluorosurfactants subgroup has a fluorinated "tail" and a hydrophilic "head" and are thus considered surfactants. These are more effective at reducing the surface tension of water than comparable hydrocarbon surfactants. They include the perfluorosulfonic acids, such as perfluorooctanesulfonic acid (PFOS), and the perfluorocarboxylic acids like perfluorooctanoic acid (PFOA).
Fluorosurfactants are surfactants containing fluorocarbon chains such as those in PFASs. Their hydrophobic nature can reduce the surface tension of water below what is attainable by using hydrocarbon surfactants, so fluorosurfactants tend to concentrate at the liquid-air interface. Fluorocarbons are both lipophobic and hydrophobic, which allows them to repel both oil and water. Their lipophobicity results from the relative lack of London dispersion forces when compared to hydrocarbons, a consequence of fluorines large electronegativity and small bond length, which reduce the polarizability of the surfactants fluorinated molecular surface. Fluorosurfactants are more stable and fit for harsher conditions than hydrocarbon surfactants because of the stability of the carbon–fluorine bond. Perfluorinated surfactants persist in the environment for the same reason. | 0 | Theoretical and Fundamental Chemistry |
Cementite (or iron carbide) is a compound of iron and carbon, more precisely an intermediate transition metal carbide with the formula FeC. By weight, it is 6.67% carbon and 93.3% iron. It has an orthorhombic crystal structure. It is a hard, brittle material, normally classified as a ceramic in its pure form, and is a frequently found and important constituent in ferrous metallurgy. While cementite is present in most steels and cast irons, it is produced as a raw material in the iron carbide process, which belongs to the family of alternative ironmaking technologies. The name cementite originated from the theory of Floris Osmond and J. Werth, in which the structure of solidified steel consists of a kind of cellular tissue, with ferrite as the nucleus and FeC the envelope of the cells. The carbide therefore cemented the iron. | 1 | Applied and Interdisciplinary Chemistry |
It can be produced by heating KSO with carbon (coke):
:KSO + 4 C → KS + 4 CO
In the laboratory, pure KS may be prepared by the reaction of potassium and sulfur in anhydrous ammonia.
Sulfide is highly basic, consequently KS completely and irreversibly hydrolyzes in water according to the following equation:
:KS + HO → KOH + KSH
For many purposes, this reaction is inconsequential since the mixture of SH and OH behaves as a source of S. Other alkali metal sulfides behave similarly. | 0 | Theoretical and Fundamental Chemistry |
In chemistry, intramolecular describes a process or characteristic limited within the structure of a single molecule, a property or phenomenon limited to the extent of a single molecule. | 0 | Theoretical and Fundamental Chemistry |
Meldrum was appointed a postdoctoral research fellow at Syracuse University, where she worked on nanoparticle assembly with Janos Fendler. Whilst there, she contributed to the book Biomimetic Materials Chemistry.
Meldrum was a Humboldt Research Fellow at the Max Planck Institute for Polymer Research, working on crystallisation using surface plasmon spectroscopy with Wolfgang Knoll. She explored chemical deposition of PbS on gold using self-assembled monolayers. Following this position, she worked at the Australian National University on biomineralisation.
Meldrum joined Queen Mary University of London as a lecturer in 1998. She moved to the University of Bristol in 2003, where she established new techniques to control crystal morphologies. In 2009 Meldrum was appointed as a Professor at the University of Leeds.
Meldrum was awarded an Engineering and Physical Sciences Research Council Fellowship in 2010. Her fellowship considers confined crystallisation in biological systems. She studied the crystallisation of calcium carbonate and calcium phosphate and their behaviour in confined systems. She demonstrated that confinement slows crystallisation, stabilising metaphases. Confined crystallisation can be used to control the polycrystalline structure of crystals. Supported by the Leverhulme Trust, Meldrum showed that even nanoscale confinement can template crystallisation. Meldrum looks to use biology to guide crystal growth, demonstrating precipitation with mould and via an amorphous precursor phase. She also looked how water-soluble block copolymers can influence the crystallisation of barium sulfate and calcium carbonate.
Meldrum's work uses nature as an inspiration for materials design. She focuses on biominerals such as bones, teeth and shells. She monitors the amorphous and precursor phases of biological crystal formation. Meldrum uses nanoparticles as additives in crystal growth, using the particle surface chemistry to tune particle occlusion. Amongst several organic additives, Meldrum has incorporated amino acids into calcite. The choice of additive is guided by genetic algorithms, resulting in the production of crystals with desired properties. She has evaluated how the surface topography impacts ice crystallisation, showing acute geometries give rise to a confined crystalline, which is followed by the formation of a bulk phase.
The Meldrum group develop microfluidic devices to monitor crystallisation processes. Crystallisation is usually difficult to monitor, as precipitation occurs very rapidly and is severely impacted by impurities. Microfluidic devices offer more control of the crystallisation rate, providing reproducible conditions for crystal growth and the potential to analyse the growth in situ. Meldrum developed a Crystal Hotel to study crystallisation in a variety of environments and equilibrium conditions. Meldrum has developed a range of experimental techniques; including Bragg coherent diffraction imaging, Brewster angle microscopy, liquid-cell Atomic force microscopy (AFM) and Infrared spectroscopy. | 0 | Theoretical and Fundamental Chemistry |
After the annexation of the Republic of Genoa to the Kingdom of Sardinia at the beginning of the 19th century, the pharmacy was further refurbished by brother Bernardino di Sant'Anna.
In those years, the Pharmacy started a cooperation with the famous Parisian surgeon Louis Le Roy, author of the treatise Healing Medicine, aka Purgation, translated in Italian for the first time in Bologna in 1824. Although its content was later superseded by improvement in scientific research, the treatise enjoyed a great success at the time and was reprinted several times. A Genoese reprint in 1885 mentioned the cooperation with SantAnnas pharmacy in the back cover.
A document stored in the library of the Convent shows that brother Modesto, whose lay name was Stefano Montabone, received his diploma of chemist in 1840, granting him permission to practice his profession in Genoa and all other territories of the Kingdom of Sardinia in accordance to letter patents issued by King Victor Emmanuel I of Savoy. In 1882, however, the difficulties in securing chemist friars with appropriate legal qualifications appeared insurmountable. Therefore, keen to remain licensed according to the law, the Convent of SantAnna decided to enact a compromise solution and appointed a lay chemist "to ensure the regular preparation and administration of the medicines'", while the business administration of the pharmacy remained entrusted to a friar.
At the end of the 19th century, the pharmacy had several prominent clients, including the main hospital of Genoa, the hospital of Pammatone. At the time, the most sought after products were white sugar, quinine, English salts, cinnamomum, rosolio, poppyseed oil, medicines against parasites and a medicine against demodicosis. | 1 | Applied and Interdisciplinary Chemistry |
Amlodipine blocks the transmembrane influx of calcium into the vascular and cardiac smooth muscles resulting in vasodilation and hence a fall in blood pressure. Levamlodipine is an allosteric modulator and acts on the L-type of calcium channels. Receptor binding studies have shown that out of the two forms only the (S)-enantiomer of amlodipine binds to and blocks L-type calcium channels whereas the (R)-enantiomer has no activity on these channels.
The precise mechanisms by which levamlodipine relieves angina have not been fully explored, but are thought to include the following:
* Decreases peripheral resistance by arteriolar vasodilatation leading to the reduction in oxygen requirement and energy consumption of cardiac smooth muscles.
* Decreases coronary vascular resistance and can lead to an increase in coronary blood flow. | 0 | Theoretical and Fundamental Chemistry |
Ethylene signaling pathway is a signal transduction in plant cells to regulate important growth and developmental processes. Acting as a plant hormone, the gas ethylene is responsible for promoting the germination of seeds, ripening of fruits, the opening of flowers, the abscission (or shedding) of leaves and stress responses. It is the simplest alkene gas and the first gaseous molecule discovered to function as a hormone.
Most of the understanding on ethylene signal transduction come from studies on Arabidopsis thaliana. Ethylene can bind to at least five different membrane receptors. Although structurally diverse, the ethylene receptors all exhibit similarity (homology) to two-component regulatory system in bacteria, indicating their common ancestry from bacterial ancestor. Ethylene binds to the receptors on the cell membrane of the endoplasmic reticulum. Although homodimers of the receptors are required for functional state, only one ethylene molecule binds to each dimer.
Unlike in other signal transductions, ethylene is the suppressor of its receptor activity. Ethylene receptors are active without ethylene due to binding with other enzymatically active co-receptors such as constitutive triple response 1 (CTR1) and ethylene insensitive 2 (EIN2). Ethylene binding causes EIN2 to split in two, of which the C-terminal portion of the protein can activate different transcription factors to bring about the effects of ethylene. There is also non-canonical pathway in which ethylene activates cytokinin receptor, and thereby regulate seed development (stomatal aperture) and growth of root (the apical meristem). | 1 | Applied and Interdisciplinary Chemistry |
Gel electrolytes – closely resemble liquid electrolytes. In essence, they are liquids in a flexible lattice framework. Various additives are often applied to increase the conductivity of such systems. | 0 | Theoretical and Fundamental Chemistry |
A fire test can be conducted to determine the degree of flammability. Test standards used to make this determination but are not limited to the following:
* Underwriters Laboratories [http://ulstandards.ul.com/standard/?id=94&edition=6&doctype=ulstd UL 94 Flammability Testing]
* International Electrotechnical Commission IEC 60707, 60695-11-10 and 60695-11-20
* International Organization for Standardization ISO 9772 and 9773.
* National Fire Protection Association [http://www.nfpa.org/aboutthecodes/AboutTheCodes.asp?DocNum=287 NFPA 287 Standard Test Methods for Measurement of Flammability of Materials in Cleanrooms Using a Fire Propagation Apparatus (FPA)]
* [http://www.nfpa.org/aboutthecodes/AboutTheCodes.asp?DocNum=701 NFPA 701: Standard Methods of Fire Tests for Flame Propagation of Textiles and Films]
* [http://www.nfpa.org/aboutthecodes/AboutTheCodes.asp?DocNum=850 NFPA 850: Recommended Practice for Fire Protection for Electric Generating Plants and High Voltage Direct Current Converter Stations] | 0 | Theoretical and Fundamental Chemistry |
If there is a temperature difference inside the thermodynamic system, for example in a rod, one end of which is warmer than the other, then thermal energy transfer processes occur in it, in which the temperature of the colder part rises and the warmer part decreases. As a result, after some time, the temperature in the rod will equalize – the rod will come to a state of thermodynamic equilibrium. | 0 | Theoretical and Fundamental Chemistry |
The phenolphthalein used in this test has been modified from its conventional form, in that it has been reduced by two electrons and is pre-dissolved in alkaline solution. This is typically achieved by boiling an alkaline solution of phenolphthalein with powdered zinc, which reduces the phenolphthalein into phenolphthalin. Upon reduction, the very intense pink color of the cationic form of phenolphthalein fades to a faint yellow color. It is this form of phenolphthalein that is present in Kastle–Meyer test kits. In order to generate the intense pink color indicative of a positive test, the reduced phenolphthalein must be oxidized back to its normal, colored form.
In the relevant reaction, hydrogen peroxide reacts with the hemoglobin in the blood. Phenolphthalein does not directly participate in this process; instead, it acts as an external source of electrons. In its reaction with hydrogen peroxide, the heme center of hemoglobin behaves as a peroxidase, reducing the peroxide to water. This activity depletes hemoglobin of electrons that are, in turn, re-supplied by the phenolphthalein. Donating electrons to hemoglobin converts the phenolphthalin back into the intensely colored phenolphthalein. As long as the enzyme survives, the reaction of heme with peroxide is catalytic, making this test very sensitive to small quantities of blood present on the test swab. The hemoglobin-catalyzed reduction of peroxide that occurs is shown in the reaction below. The two electrons are supplied by phenolphthalein:
: HOOH + 2 e + 2 H → 2 HO
The consumption of protons during the course of the reaction has the effect of raising the pH of the solution, but the amount of base produced is negligible compared to the amount of base already present in the reagent mixture. | 0 | Theoretical and Fundamental Chemistry |
SELDM was developed as a Microsoft Access® database software application to facilitate storage, handling, and use of the hydrologic dataset with a simple graphical user interface (GUI). The program's menu-driven GUI uses standard Microsoft Visual Basic for Applications® (VBA) interface controls to facilitate entry, processing, and output of data. Appendix 4 of the SELDM manual has detailed instructions for using the GUI.
The SELDM user interface has one or more GUI forms that are used to enter four categories of input data, which include documentation, site and region information, hydrologic statistics, and water-quality data. The documentation data include information about the analyst, the project, and the analysis. The site and region data include the highway-site characteristics, the ecoregions, the upstream-basin characteristics, and, if a lake analysis is selected, the lake-basin characteristics. The hydrologic data include precipitation, streamflow, and runoff-coefficient statistics. The water-quality data include highway-runoff-quality statistics, upstream-water-quality statistics, downstream-water-quality definitions, and BMP-performance statistics. There also is a GUI form for running the model and accessing the distinct set of output files. The SELDM interface is designed to populate the database with data and statistics for the analysis and to specify index variables that are used by the program to query the database when SELDM is run. It is necessary to step through the input forms each time an analysis is run. | 1 | Applied and Interdisciplinary Chemistry |
The mechanism entails nucleophilic attack of water or hydroxide on a M-CO center, generating a metallacarboxylic acid. | 0 | Theoretical and Fundamental Chemistry |
Steric effects are critical to chemistry, biochemistry, and pharmacology. In organic chemistry, steric effects are nearly universal and affect the rates and activation energies of most chemical reactions to varying degrees.
In biochemistry, steric effects are often exploited in naturally occurring molecules such as enzymes, where the catalytic site may be buried within a large protein structure. In pharmacology, steric effects determine how and at what rate a drug will interact with its target bio-molecules. | 0 | Theoretical and Fundamental Chemistry |
Water mist systems are used for special hazards applications. This type of system is typically used where water damage may be a concern, or where water supplies are limited. NFPA 750 defines water mist as a water spray with a droplet size of "less than 1000 microns at the minimum operation pressure of the discharge nozzle". The droplet size can be controlled by adjusting the discharge pressure through a nozzle of a fixed orifice size. The fire suppression mechanisms provided by water mist systems include cooling, local flame oxygen reduction, and radiation blocking.
In operation, water mist systems can operate with the same functionality as deluge, wet pipe, dry pipe, or pre-action systems. The difference is that a water mist system uses a compressed gas as an atomizing medium, which is pumped through the sprinkler pipe. Instead of compressed gas, some systems use a high-pressure pump to pressurize the water so it atomizes as it exits the sprinkler nozzle. Systems can be applied using local application method or total flooding method, similar to Clean Agent Fire Protection Systems. | 1 | Applied and Interdisciplinary Chemistry |
#Isolate the fly genome.
#Undergo a light digest (using an enzyme [enzyme 1] known to cut in the boundary between the reporter gene and the E. coli reporter gene and plasmid sequences), giving fragments of a few kilobases, a few with the E. coli reporter, the plasmid sequences and its flanking DNA.
#Self ligate the digest (low DNA concentration to ensure self ligation) giving a selection of circular DNA fragments, a few with the E. coli reporter, the plasmid sequences and its flanking DNA.
#Insert the plasmids into E. coli cells (e.g. by electroporation).
#Select plasmids for the E. coli selectable marker gene. Only successful inserts of plasmids with the plasmid housekeeping sequences will express this gene.
#The gene can be cloned for further analysis. | 1 | Applied and Interdisciplinary Chemistry |
Subject to any regulations restricting who can obtain donor sperm, donor sperm is available to all people who, for whatever reason, wish to have a child. These regulations vary significantly across jurisdictions, and some countries do not have any regulations. When an individual finds that they are barred from receiving donor sperm within their jurisdiction, they may travel to another jurisdiction to obtain sperm. Regulations change from time to time. In most jurisdictions, donor sperm is available to an individual if their partner is infertile or where they have a genetic disorder. However, the categories of individuals who may obtain donor sperm is expanding, with its availability to single persons and to same-sex couples becoming more common, and some sperm banks supply fertility centers which specialize in the treatment of such people.
Frozen vials of donor sperm may be shipped by the sperm bank to a recipient's home for self-insemination, or they may be shipped to a fertility clinic or physician for use in fertility treatments. The sperm bank will rely on the recipient woman or medical practitioner to report the outcome of any use of the sperm to the sperm bank. This enables a sperm bank to adhere to any national limits of pregnancy numbers. The sperm bank may also impose its own worldwide limit on numbers.
Sperm is introduced into the recipient by means of artificial insemination or by IVF. The most common technique is conventional artificial insemination which consists of a catheter to put the sperm into the vagina where it is deposited at the entrance to the cervix. In biological terms, this is much the same process as when semen is ejaculated from the penis during sexual intercourse. Owing to its simplicity, this method of insemination is commonly used for home and self inseminations principally by single women and lesbians. Other types of uses include intrauterine insemination (IUI) and deep intrauterine artificial insemination where washed sperm must be used. These methods of insemination are most commonly used in fertility centers and clinics mainly because they produce better pregnancy rates than ICI insemination especially where the woman has no underlying fertility issues.
Men may also store their own sperm at a sperm bank for future use particularly where they anticipate traveling to a war zone or having to undergo chemotherapy which might damage the testes.
Sperm from a sperm donor may also be used in surrogacy arrangements and for creating embryos for embryo donation. Donor sperm may be supplied by the sperm bank directly to the recipient to enable a woman to perform her own artificial insemination which can be carried out using a needleless syringe or a cervical cap conception device. The cervical cap conception device allows the donor semen to be held in place close to the cervix for between six and eight hours to allow fertilization to take place. Alternatively, donor sperm can be supplied by a sperm bank through a registered medical practitioner who will perform an appropriate method of insemination or IVF treatment using the donor sperm in order for the woman to become pregnant. | 1 | Applied and Interdisciplinary Chemistry |
Defoamers are used in many industrial processes and products: wood pulp, paper, paint, industrial wastewater treatment, food processing, oil drilling, machine tool industry, oils cutting tools, hydraulics, etc. | 0 | Theoretical and Fundamental Chemistry |
The dative anchoring strategy uses natural amino acid residue in the protein like His, Cys, Glu, Asp and Ser to coordinate to a metal center. Like the first example of Pd-fibroin, dative anchoring is not commonly used now and often resulted in a more ambiguous binding site for metal compared with previous three methods. | 0 | Theoretical and Fundamental Chemistry |
Henry's law solubility constant for a gas 2 in a mixture M of two solvents 1 and 3 depends on the individual constants for each solvent, and according to:
Where , are the molar ratios of each solvent in the mixture and a is the interaction parameter of the solvents from Wohl expansion of the excess chemical potential of the ternary mixtures.
A similar relationship can be found for the volatility constant , by remembering that and that, both being positive real numbers, , thus:
For a water-ethanol mixture, the interaction parameter a has values around for ethanol concentrations (volume/volume) between 5% and 25%. | 0 | Theoretical and Fundamental Chemistry |
In order to perform the test, a sufficient sample of the aggregate must be obtained from the source. To prepare the sample, the aggregate should be mixed thoroughly and be reduced to a suitable size for testing. The total mass of the sample is also required. | 1 | Applied and Interdisciplinary Chemistry |
The SI unit of dynamic viscosity is the newton-second per square meter (N·s/m), also frequently expressed in the equivalent forms pascal-second (Pa·s), kilogram per meter per second (kg·m·s) and poiseuille (Pl). The CGS unit is the poise (P, or g·cm·s = 0.1 Pa·s), named after Jean Léonard Marie Poiseuille. It is commonly expressed, particularly in ASTM standards, as centipoise (cP). The centipoise is convenient because the viscosity of water at 20 °C is about 1 cP, and one centipoise is equal to the SI millipascal second (mPa·s).
The SI unit of kinematic viscosity is square meter per second (m/s), whereas the CGS unit for kinematic viscosity is the stokes (St, or cm·s = 0.0001 m·s), named after Sir George Gabriel Stokes. In U.S. usage, stoke is sometimes used as the singular form. The submultiple centistokes (cSt) is often used instead, 1 cSt = 1 mm·s = 10 m·s. 1 cSt is 1 cP divided by 1000 kg/m^3, close to the density of water. The kinematic viscosity of water at 20 °C is about 1 cSt.
The most frequently used systems of US customary, or Imperial, units are the British Gravitational (BG) and English Engineering (EE). In the BG system, dynamic viscosity has units of pound-seconds per square foot (lb·s/ft), and in the EE system it has units of pound-force-seconds per square foot (lbf·s/ft). The pound and pound-force are equivalent; the two systems differ only in how force and mass are defined. In the BG system the pound is a basic unit from which the unit of mass (the slug) is defined by Newtons Second Law, whereas in the EE system the units of force and mass (the pound-force and pound-mass respectively) are defined independently through the Second Law using the proportionality constant g'.
Kinematic viscosity has units of square feet per second (ft/s) in both the BG and EE systems.
Nonstandard units include the reyn, a British unit of dynamic viscosity. In the automotive industry the viscosity index is used to describe the change of viscosity with temperature.
The reciprocal of viscosity is fluidity, usually symbolized by or , depending on the convention used, measured in reciprocal poise (P, or cm·s·g), sometimes called the rhe. Fluidity is seldom used in engineering practice.
At one time the petroleum industry relied on measuring kinematic viscosity by means of the Saybolt viscometer, and expressing kinematic viscosity in units of Saybolt universal seconds (SUS). Other abbreviations such as SSU (Saybolt seconds universal) or SUV (Saybolt universal viscosity) are sometimes used. Kinematic viscosity in centistokes can be converted from SUS according to the arithmetic and the reference table provided in ASTM D 2161. | 1 | Applied and Interdisciplinary Chemistry |
Activated sludge is also the name given to the active biological material produced by activated sludge plants. Excess sludge is called "surplus activated sludge" or "waste activated sludge" and is removed from the treatment process to keep "food to biomass" (F/M) ratio in balance (where biomass refers to the activated sludge). This sewage sludge is usually mixed with primary sludge from the primary clarifiers and undergoes further sludge treatment for example by anaerobic digestion, followed by thickening, dewatering, composting and land application.
The amount of sewage sludge produced from the activated sludge process is directly proportional to the amount of wastewater treated. The total sludge production consists of the sum of primary sludge from the primary sedimentation tanks as well as waste activated sludge from the bioreactors. The activated sludge process produces about of waste activated sludge (that is grams of dry solids produced per cubic metre of wastewater treated). is regarded as being typical. In addition, about of primary sludge is produced in the primary sedimentation tanks which most - but not all - of the activated sludge process configurations use. | 1 | Applied and Interdisciplinary Chemistry |
Such soils natively have little tilth, especially once they have been disturbed. Adding organic matter up to 25% by volume can help compensate. For example, if tilling to a depth of eight inches, add two inches of organic materials. | 0 | Theoretical and Fundamental Chemistry |
The decay scheme on the left shows that Hg produces a continuous beta spectrum with maximum energy 214 keV, that leads to an excited state of the daughter nucleus Tl. This state decays very quickly (within 2.8×10 s) to the ground state of Tl, emitting a gamma quantum of 279 keV.
The figure on the right shows the electron spectrum of Hg, measured by means of a magnetic spectrometer. It includes the continuous beta spectrum and K-, L-, and M-lines due to internal conversion. Since the binding energy of the K electrons in Tl is 85 keV, the K line has an energy of 279 - 85 = 194 keV. Due to lesser binding energies, the L- and M-lines have higher energies. Due to the finite energy resolution of the spectrometer, the "lines" have a Gaussian shape of finite width. | 0 | Theoretical and Fundamental Chemistry |
Although the nuclearity of binary metal carbonyl clusters is usually six or fewer, carbido clusters often have higher nuclearities. Metal carbonyls of the iron and cobalt triads are well known to form carbido derivatives. Examples include [RhC(CO)] and [RuC(CO)]. Carbonyl carbides exist not only with fully encapsulated carbon (e.g., [FeC(CO)]) but also with exposed carbon centres as in FeC(CO) and FeC(CO). | 0 | Theoretical and Fundamental Chemistry |
Car customizing is a form of retrofitting, where older vehicles are fitted with new technologies: power windows, cruise control, remote keyless systems, electric fuel pumps, driverless systems, etc.
Trucks and agricultural machines can also be given retrofits to make them driverless. | 1 | Applied and Interdisciplinary Chemistry |
The phrase originates from the French word espoilelier, a verb conveying the meaning: to seize by violence, to plunder, to take by force. | 1 | Applied and Interdisciplinary Chemistry |
Two clades of dsRNA viruses exist: the phylum Duplornaviricota and the class Duplopiviricetes, which is in the phylum Pisuviricota. Both are included in the kingdom Orthornavirae in the realm Riboviria. Based on phylogenetic analysis of RdRp, the two clades do not share a common dsRNA ancestor but are instead separately descended from different positive-sense, single-stranded RNA viruses. In the Baltimore classification system, which groups viruses together based on their manner of mRNA synthesis, dsRNA viruses are group III. | 1 | Applied and Interdisciplinary Chemistry |
A Liman (from Greek λιμήν) in Israel is the name for an artificial earthen construction used to collect floodwater by damming a desert wadi. The runoff water is slowed by the dam, thus flooding a small area and allowing the water to infiltrate into the soil. This way, a small groves of trees can be sustained in the desert. The JNF-KKL has been funding the construction of limans in the Negev Desert. | 1 | Applied and Interdisciplinary Chemistry |
ProteaseMAX'is the brandname of Promega for sodium 3-((1-(furan-2-yl)undecyloxy)carbonylamino)propane-1-sulfonate. This cleavable detergent is sensitive to heat and acid and is degraded during a typical trypsin digestion into the uncharged lipophilic compound 1-(furan-2-yl)undecan-1-ol and the zwitterionic 3-aminopropane-1-sulfonic acid (homotaurine), which can be removed by C18 solid phase extraction during sample work-up. | 0 | Theoretical and Fundamental Chemistry |
The main reason to use microspectrophotometry is the ability to measure the optical spectra of samples with a spatial resolution on the micron scale. Optical spectra may be acquired of either microscopic samples or larger samples with a micron-scale spatial resolution. Another reason microspectrophotometry is useful is that measurements are made without destroying the samples. This is important when dealing with stained/unstained histological or cytochemical biological sections, when measuring film thickness in semi-conductor integrated circuits, when matching paints and fibers (forensic science), when studying gems and coal (geology), and in paint/ink/color analysis in paint chemistry or art-work. | 0 | Theoretical and Fundamental Chemistry |
Stoichiometric phases are named compositionally. Non-stoichiometric phases are more difficult. Where possible formulae should be used but where necessary naming such as the following may be used:
* (iron deficient)
* (carbon excess) | 0 | Theoretical and Fundamental Chemistry |
A person's metabolism varies with their physical condition and activity. Weight training can have a longer impact on metabolism than aerobic training, but there are no known mathematical formulas that can exactly predict the length and duration of a raised metabolism from trophic changes with anabolic neuromuscular training.
A decrease in food intake will typically lower the metabolic rate as the body tries to conserve energy. Researcher Gary Foster estimates that a very low calorie diet of fewer than 800 calories a day would reduce the metabolic rate by more than 10 percent.
The metabolic rate can be affected by some drugs, such as antithyroid agents, drugs used to treat hyperthyroidism, such as propylthiouracil and methimazole, bring the metabolic rate down to normal and restore euthyroidism. Some research has focused on developing antiobesity drugs to raise the metabolic rate, such as drugs to stimulate thermogenesis in skeletal muscle.
The metabolic rate may be elevated in stress, illness, and diabetes. Menopause may also affect metabolism. | 1 | Applied and Interdisciplinary Chemistry |
Stains-all is metachromatic and changes its color dependent on its contact to other molecules. The detection limit for phosphoproteins is below 1 ng after one hour of staining, for anionic polysaccharides between 10 and 500 ng. Highly anionic proteins are stained blue, proteoglycans purple and anionic proteins pink. RNA is stained blueish-purple with a detection limit of 90 ng and DNA is stained blue with a detection limit of 3 ng.
Stains-all is light sensitive, therefore the staining is performed in the absence of light and photographed immediately. Staining of proteins can be improved by a subsequent silver stain. The analogue Ethyl-Stains-all has similar properties as stains all, with differences in solubility and staining properties. | 1 | Applied and Interdisciplinary Chemistry |
J.W. Gibbs developed the thermodynamic theory of capillarity based
on the idea of surfaces of discontinuity. Gibbs considered the case of a sharp mathematical surface being placed somewhere within the microscopically fuzzy physical interface that exists between two homogeneous substances. Realizing that the exact choice of the surface's location was somewhat arbitrary, he left it flexible. Since the interface exists in thermal and chemical equilibrium with the substances around it (having temperature and chemical potentials ), Gibbs considered the case where the surface may have excess energy, excess entropy, and excess particles, finding the natural free energy function in this case to be , a quantity later named as the grand potential and given the symbol .
Considering a given subvolume containing a surface of discontinuity, the volume is divided by the mathematical surface into two parts A and B, with volumes and , with exactly. Now, if the two parts A and B were homogeneous fluids (with pressures , ) and remained perfectly homogeneous right up to the mathematical boundary, without any surface effects, the total grand potential of this volume would be simply . The surface effects of interest are a modification to this, and they can be all collected into a surface free energy term so the total grand potential of the volume becomes:
For sufficiently macroscopic and gently curved surfaces, the surface free energy must simply be proportional to the surface area:
for surface tension and surface area .
As stated above, this implies the mechanical work needed to increase a surface area A is , assuming the volumes on each side do not change. Thermodynamics requires that for systems held at constant chemical potential and temperature, all spontaneous changes of state are accompanied by a decrease in this free energy , that is, an increase in total entropy taking into account the possible movement of energy and particles from the surface into the surrounding fluids. From this it is easy to understand why decreasing the surface area of a mass of liquid is always spontaneous, provided it is not coupled to any other energy changes. It follows that in order to increase surface area, a certain amount of energy must be added.
Gibbs and other scientists have wrestled with the arbitrariness in the exact microscopic placement of the surface. For microscopic surfaces with very tight curvatures, it is not correct to assume the surface tension is independent of size, and topics like the Tolman length come into play. For a macroscopic-sized surface (and planar surfaces), the surface placement does not have a significant effect on ; however, it does have a very strong effect on the values of the surface entropy, surface excess mass densities, and surface internal energy, which are the partial derivatives of the surface tension function .
Gibbs emphasized that for solids, the surface free energy may be completely different from surface stress (what he called surface tension): the surface free energy is the work required to form the surface, while surface stress is the work required to stretch the surface. In the case of a two-fluid interface, there is no distinction between forming and stretching because the fluids and the surface completely replenish their nature when the surface is stretched. For a solid, stretching the surface, even elastically, results in a fundamentally changed surface. Further, the surface stress on a solid is a directional quantity (a stress tensor) while surface energy is scalar.
Fifteen years after Gibbs, J.D. van der Waals developed the theory of capillarity effects based on the hypothesis of a continuous variation of density. He added to the energy density the term where c is the capillarity coefficient and ρ is the density. For the multiphase equilibria, the results of the van der Waals approach practically coincide with the Gibbs formulae, but for modelling of the dynamics of phase transitions the van der Waals approach is much more convenient. The van der Waals capillarity energy is now widely used in the phase field models of multiphase flows. Such terms are also discovered in the dynamics of non-equilibrium gases. | 0 | Theoretical and Fundamental Chemistry |
Allosteric modulators of small SK channels work by changing the apparent calcium sensitivity of the channels. Examples include:
* Riluzole
* Non-selective positive modulators of SK channels: EBIO (1-Ethyl-2-BenzimIdazolinOne), NS309 (6,7-dichloro-1H-indole-2,3-dione 3-oxime)
* SK-2 and SK-3 selective positive modulators : CyPPA (NS6277; Cyclohexyl-(2-(3,5-dimethyl-Pyrazol-1-yl)-6-methyl-Pyrimidin-4-yl)-Amine)
<br /> | 1 | Applied and Interdisciplinary Chemistry |
Due to the proximity of the Westinghouse site and other former manufacturing sites to the Watsessing Station, the Township of Bloomfield worked on the plan for transit-oriented development in that area. The Westinghouse site, although a brownfield site with ongoing remediation at the time, was re-zoned into Commuter Oriented Residential District which was a mixed-use concept that included high-density residential units which would be close to the train station.
The redevelopment was completed. The luxury apartments were marketed as "The Grove at Watsessing" which was part of the "Grove Crossing" complex. | 1 | Applied and Interdisciplinary Chemistry |
Equivalently
and in a minerals processing context where the specific gravity of the liquid (water) is taken to be one:
So
and
Then combining with the first equation:
So
Then since
we conclude that
where
: is the solids fraction of the slurry on a volumetric basis
: is the solids fraction of the slurry on a mass basis
: is the mass or mass flow of solids in the sample or stream
: is the mass or mass flow of slurry in the sample or stream
: is the mass or mass flow of liquid in the sample or stream
: is the bulk specific gravity of the solids | 1 | Applied and Interdisciplinary Chemistry |
A quantity equation, also sometimes called a complete equation, is an equation that remains valid independently of the unit of measurement used when expressing the physical quantities.
In contrast, in a numerical-value equation, just the numerical values of the quantities occur, without units. Therefore, it is only valid when each numerical values is referenced to a specific unit.
For example, a quantity equation for displacement as speed multiplied by time difference would be:
for = 5 m/s, where and may be expressed in any units, converted if necessary.
In contrast, a corresponding numerical-value equation would be:
where is the numeric value of when expressed in seconds and is the numeric value of when expressed in metres.
Generally, the use of numerical-value equations is discouraged. | 1 | Applied and Interdisciplinary Chemistry |
This method adds to the dilution to threshold method by considering the perceived intensity of the compounds as well. Assessors can report this based on a predetermined scale.
The posterior intensity method measures the maximum intensity perceived for each eluting compound. A panel of assessors is recommended to be used to obtain an averaged signal. On the other hand, the dynamic time-intensity method measures
the intensity at different points in time starting from the time of elution, allowing a continuous measurement of onset, maximum, and decline of the odour intensity. This is used in the Osme (Greek word for odour) method developed in 1992 by Da Silva. An aromagram can then be constructed in a similar way as an FID chromatogram whereby intensity is plotted as a function of retention time. The peak height corresponds to the maximum intensity perceived whereas the peak width corresponds to the duration of the odour perceived.
The time requirement maybe high for this particular method regarding the essentials of assessor training, as lack of training may result in inconsistencies in scale usage. However, with a trained panel of assessors, the analysis can be done in a relatively short amount of time with high precision. | 0 | Theoretical and Fundamental Chemistry |
Source:
* Strickler, A. (1923). “Contributions to the question of velocity formula and the roughness numbers for rivers, channels and pipes.” Mitteilung 16, C. Mutzner, ed., Amt für Wasserwirtschaft, Bern, Switzerland (in German).
* Strickler, A. (1924). “Drag resistance of propeller boats, and their performance in inland navigation.” Mitteilung 17, Amt für Wasserwirtschaft, Bern, Switzerland (in German).
* Strickler, A. (1925). “The regulation of Rhine River between Strassburg and Basle.” Schweizerische Techniker-Zeitung, 22(33), 389–394 (in German).
* Strickler, A. (1926). “Studies on measurement of discharge.” Mitteilung 18, C. Mutzner, ed., Amt für Wasserwirtschaft, Bern, Switzerland (in German).
* Strickler, A. (1926). “Relation between the Swiss hydropower development and inland navigation.” Werft, Reederei, Hafen, 7(14), 345–346 (in German).
* Strickler, A. (1930). “The question of the coefficient in Chézy’s formula.” Gesamtbericht der 2. Weltkraftkonferenz, Berlin, 2, 137–152 (in German). | 1 | Applied and Interdisciplinary Chemistry |
Dicarbollide complexes have been investigated for many years, but commercial applications are rare. The bis(dicarbollide) has been used as a precipitant for removal of from radiowastes.
The medical applications of carboranes have been explored. C-functionalized carboranes represent a source of boron for boron neutron capture therapy.
The compound is a superacid, forming an isolable salt with protonated benzene cation, (benzenium cation). The formula of that salt is . The superacid protonates fullerene, . | 0 | Theoretical and Fundamental Chemistry |
Sir Thomas Neil Morris Waters (10 April 1931 – 7 June 2018) was a New Zealand inorganic chemist and academic administrator who served as vice-chancellor of Massey University from 1983 to 1995. He is noted for establishing the university's Albany campus near Auckland in 1993. | 0 | Theoretical and Fundamental Chemistry |
Vancomycin was first isolated in 1953, by Edmund Kornfeld (working at Eli Lilly) from a bacteria in a soil sample collected from the interior jungles of Borneo by a missionary, William M. Bouw (1918–2006). The organism that produced it was eventually named Amycolatopsis orientalis. The original indication for vancomycin was for the treatment of penicillin-resistant Staphylococcus aureus.
The compound was initially called compound 05865, but was eventually given the generic name vancomycin, derived from the term "vanquish". One advantage that was quickly apparent was that staphylococci did not develop significant resistance, despite serial passage in culture media containing vancomycin. The rapid development of penicillin resistance by staphylococci led to its being fast-tracked for approval by the Food and Drug Administration. In 1958, Eli Lilly first marketed vancomycin hydrochloride under the trade name Vancocin.
Vancomycin never became the first-line treatment for S. aureus for several reasons:
# It possesses poor oral bioavailability, so must be given intravenously for most infections.
# β-Lactamase-resistant semisynthetic penicillins such as methicillin (and its successors, nafcillin and cloxacillin) were subsequently developed, which have better activity against non-MRSA staphylococci.
# Early trials used early, impure forms of the drug ("Mississippi mud"), which were found to be toxic to the inner ear and to the kidneys; these findings led to vancomycin's being relegated to the position of a drug of last resort.
In 2004, Eli Lilly licensed Vancocin to ViroPharma in the U.S., Flynn Pharma in the UK, and Aspen Pharmacare in Australia. The patent had expired in the early 1980s, and the FDA authorized the sale of several generic versions in the US, including from manufacturers Bioniche Pharma, Baxter Healthcare, Sandoz, Akorn-Strides, and Hospira. | 0 | Theoretical and Fundamental Chemistry |
In the upper deck, the solution is found to given by
where . Furthermore, the upper deck problem also provides the relation between the displacement and the pressure function as
in which stands for Cauchy principal value. One may notice that the pressure function and the derivative of the displacement function (aka transverse velocity) forms a Hilbert transform pair. | 1 | Applied and Interdisciplinary Chemistry |
Kurt Heikki Olavi Erämetsä was borh to Kurt H. Enwald and Ingrid Viola Ryberg on October 10, 1906. The Enwald family changed its name to Erämetsä in 1936.
Kurt H. Enwald and Ingrid Viola Ryberg were teachers of science at the Kuopio Lyseo. | 1 | Applied and Interdisciplinary Chemistry |
Masahiro Ishiura, Takao Kondo, Susan S. Golden, Carl H. Johnson, and their colleagues discovered the gene cluster in 1998 and named the gene cluster kaiABC, as "kai" means “cycle” in Japanese. They generated 19 different clock mutants that were mapped to kaiA, kaiB, and kaiC genes, and successfully cloned the gene cluster in the cyanobacteria Synechococcus elongatus. Using a bacterial luciferase reporter to monitor the expression of clock-controlled gene psbAI in Synechococcus, they investigated and reported on the rescue to normal rhythmicity of long-period clock mutant C44a (with a period of 44 hours) by kaiABC. They inserted wild-type DNA through a pNIBB7942 plasmid vector into the C44a mutant, and generated clones that restored normal period (a period of 25 hours). They were eventually able to localize the gene region causing this rescue, and observed circadian rhythmicity in upstream promotor activity of kaiA and kaiB, as well as in the expression of kaiA and kaiBC messenger RNA. They determined abolishing any of the three kai genes would cause arrhythmicity in the circadian clock and reduce kaiBC promoter activity. KaiC was later found to have both autokinase and autophosphatase activity. These findings suggested that circadian rhythm was controlled by a TTFL mechanism, which is consistent with other known biological clocks.
In 2000, S. elongatus was observed in constant dark (DD) and constant light (LL). In DD, transcription and translation halted due to the absence of light but the circadian mechanism showed no significant phase shift after transitioning to constant light. In 2005, after closer examination of the KaiABC protein interactions, the phosphorylation of KaiC proved to oscillate with daily rhythms in the absence of light. In addition to the TTFL model, the PTO model was hypothesized for the KaiABC phosphorylation cycle.
Also in 2005, Nakajima et al. lysed S. elongatus and isolated KaiABC proteins. In test tubes containing only KaiABC proteins and ATP, in vitro phosphorylation of KaiC oscillated with a near 24 hour period with a slightly smaller amplitude than in vivo oscillation, proving that the KaiABC proteins are sufficient for circadian rhythm solely in the presence of ATP. Combined with the TTFL model, KaiABC as a circadian PTO was shown to be the fundamental clock regulator in S. elongatus | 1 | Applied and Interdisciplinary Chemistry |
Steric characteristics of the diphosphine ligand that influence the regioselectivity and rate of catalysis include the pocket angle, solid angle, repulsive energy, and accessible molecular surface. Also of importance is the cone angle, which in diphosphines is defined as the average of the cone angle for the two substituents attached to the phosphorus atoms, the bisector of the P–M–P angle, and the angle between each M–P bond. Larger cone angles usually result in faster dissociation of phosphine ligands because of steric crowding. | 0 | Theoretical and Fundamental Chemistry |
An early application of TRMS was in the observation of flash photolysis process. It took advantage of a time-of-flight mass analyzer.
TRMS currently finds applications in the monitoring of organic reactions, formation of reactive intermediates, enzyme-catalyzed reactions, convection, protein folding, extraction, and other chemical and physical processes. | 1 | Applied and Interdisciplinary Chemistry |
Chinese researchers have utilized LEAPER to restore functional enzyme activity in cells from patients with Hurler syndrome. They have claimed that LEAPER could have the potential to treat almost half of all known hereditary disorders.
Highly specific editing efficiencies of up to 80% can be achieved when LEAPER editing using arRNA151 is delivered via a plasmid or viral vector or as a synthetic oligonucleotide, though this efficiency varied significantly across cell types. Based on these preliminary results, LEAPER may have the most therapeutic promise with no production of functional protein but if a partial restoration of protein expression would provide therapeutic benefit. For example, in human cells with defective α-L-iduronidase (IDUA) expression in cells from patients with IDUA-defective Hurler syndrome, LEAPER resulted in a W53X truncation mutant of p53 being edited using arRNA151 to achieve a "normal" p53 translation and functional p53-mediated transcriptional responses. | 1 | Applied and Interdisciplinary Chemistry |
In 1938, he married Irja Pullman; they had two daughters: Siiri Anna (b. 1939) and Jean Kirsten (b. 1944). In 1946, he married Eudoxia Muller, an artist and technician whom he met at the Polaroid Corp. This marriage, which lasted until 1972, produced a daughter, and a son: Crystal Elisabeth (b. 1947), and Eric Richard Arthur (b. 1953). | 0 | Theoretical and Fundamental Chemistry |
Syntheses of large complex catalysts are time and resource consuming. An unexpected deviation from the design could be disastrous. Once a catalyst is discovered, modification for further adjustment could be so synthetically challenging that it is easier to study the poor catalyst than to improve it. | 0 | Theoretical and Fundamental Chemistry |
Subsets and Splits
No community queries yet
The top public SQL queries from the community will appear here once available.