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Electrofiltration is a technique for separation and concentration of colloidal substances – for instance biopolymers. The principle of electrofiltration is based on overlaying electric field on a standard dead-end filtration. Thus the created polarity facilitates electrophoretic force which is opposite to the resistance force of the filtrate flow and directs the charged biopolymers. This provides extreme decrease in the film formation on the micro- or ultra-filtration membranes and the reduction of filtration time from several hours by standard filtration to a few minutes by electrofiltration. In comparison to cross-flow filtration electrofiltration exhibits not only increased permeate flow but also guarantees reduced shear force stress which qualifies it as particularly mild technique for separation of biopolymers that are usually unstable.
The promising application in purification of biotechnological products is based on the fact that biopolymers are difficult for filtration but on the other hand they are usually charged as a result of the presence of amino and carboxyl groups. The objective of electrofiltration is to prevent the formation of filter cake and to improve the filtration kinetic of products difficult to filtrate.
The electrophoresis of the particles and the electro-osmosis become essential when the filtration process is overlaid with electric field. By electrofiltration the conventional filtration is overlaid with an electric field (DC) which works parallel with the filtrate’s flow direction. When the electrophoretic force F, oppositely directed to flow, overruns the hydrodynamic resistance force F, the charged particles migrate from the filter medium, thus reducing significantly the thickness of the filter cake on the membrane.
When the solid particles, subject to separation, are negatively charged they migrate towards the anode (positive pole) and deposit on the filter cloth situated there. As a result, on the cathode side’s membrane (negative pole) there is only a very thin film allowing nearly the whole filtrate to efflux through this membrane.
Figure 1 presents schematic description of electrofiltration chamber with flushing electrodes. For the flushing circulation a buffer solution is used. This approach has been patented. | 1 | Separation Processes |
SPMR measurements depend on the characteristics of the nanoparticle (NP) that is used. The NP must have the property that the bulk material is normally ferromagnetic in the bulk. Magnetite (FeO) is one such example as it is ferromagnetic when below its Curie temperature. However, if the NPs are single domain, and of a size less than ~50 nm, they exhibit paramagnetic properties even below the Curie temperature due to the energy of the NP being dominated by thermal activity rather than magnetic energy. If an external magnetic field is applied, the NPs align with that field and have a magnetic moment now characteristic of ferromagnetic behavior. When this external field is removed, the NPs relax back to their paramagnetic state.
The size of the NP determines the rate of decay of the relaxation process after the extinction of the external magnetization field. The NP decay rate also depends on whether the particle is bound (tethered) to a surface, or is free to rotate. The latter case is dominated by thermal activity, Brownian motion.
For the bound case, the decay rate is given by the Néel equation
Here the value of is normally taken as  ≈ 10 s, is the anisotropy energy density of the magnetic material (1.35 × 10 J/m), the magnetic core volume, is Boltzmann’s constant, and is the absolute temperature. This exponential relationship between the particle volume and the decay time implies a very strong dependence on the diameter of the NP used in SPMR studies, requiring precise size restrictions on producing these particles.
For magnetite, this requires a particle diameter of ~25 nm. The NP also require high monodispersity around this diameter as NP a few nm below this value will decay too fast and a few nm above will decay too slowly to fit into the time window of the measurement.
The value of the time constant, , depends on the method of fabrication of the NP. Different chemical procedures will produce slightly different values as well as different NP magnetic moments. Equally important characteristics of the NP are monodispersity, single domain character, and crystalline structure. | 3 | Magnetic Ordering |
Since ethanol boils at a much lower temperature than water, simple distillation can separate ethanol from water by applying heat to the mixture. Historically, a copper vessel was used for this purpose, since copper removes undesirable sulfur-based compounds from the alcohol. However, many modern stills are made of stainless steel pipes with copper linings to prevent erosion of the entire vessel and lower copper levels in the waste product (which in large distilleries is processed to become animal feed). Copper is the preferred material for stills because it yields an overall better-tasting spirit. The taste is improved by the chemical reaction between the copper in the still and the sulfur compounds created by the yeast during fermentation. These unwanted and flavor-changing sulfur compounds are chemically removed from the final product resulting in a smoother, better-tasting drink. All copper stills will require repairs about every eight years due to the precipitation of copper-sulfur compounds. The beverage industry was the first to implement a modern distillation apparatus and led the way in developing equipment standards which are now widely accepted in the chemical industry.
There is also an increasing usage of the distillation of gin under glass and PTFE, and even at reduced pressures, to facilitate a fresher product. This is irrelevant to alcohol quality because the process starts with triple distilled grain alcohol, and the distillation is used solely to harvest botanical flavors such as limonene and other terpene like compounds. The ethyl alcohol is relatively unchanged.
The simplest standard distillation apparatus is commonly known as a pot still, consisting of a single heated chamber and a vessel to collect purified alcohol. A pot still incorporates only one condensation, whereas other types of distillation equipment have multiple stages which result in higher purification of the more volatile component (alcohol). Pot still distillation gives an incomplete separation, but this can be desirable for the flavor of some distilled beverages.
If a purer distillate is desired, a reflux still is the most common solution. Reflux stills incorporate a fractionating column, commonly created by filling copper vessels with glass beads to maximize available surface area. As alcohol boils, condenses, and reboils through the column, the effective number of distillations greatly increases. Vodka and gin and other neutral grain spirits are distilled by this method, then diluted to concentrations appropriate for human consumption.
Alcoholic products from home distilleries are common throughout the world but are sometimes in violation of local statutes. The product of illegal stills in the United States is commonly referred to as moonshine and in Ireland, poitín. However, poitín, although made illegal in 1661, has been legal for export in Ireland since 1997. Note that the term moonshine itself is often misused as many believe it to be a specific kind of high-proof alcohol that was distilled from corn, but the term can refer to any illicitly distilled alcohol. | 1 | Separation Processes |
TTM has been studied in several use scenarios where it has not usually been found to be helpful, or is still under investigation, despite theoretical grounds for its usefulness. | 0 | Cryobiology |
The quantum Heisenberg model, developed by Werner Heisenberg, is a statistical mechanical model used in the study of critical points and phase transitions of magnetic systems, in which the spins of the magnetic systems are treated quantum mechanically. It is related to the prototypical Ising model, where at each site of a lattice, a spin represents a microscopic magnetic dipole to which the magnetic moment is either up or down. Except the coupling between magnetic dipole moments, there is also a multipolar version of Heisenberg model called the multipolar exchange interaction. | 3 | Magnetic Ordering |
Hypothermia can happen in most mammals in cold weather and can be fatal. Baby mammals such as kittens are unable to regulate their body temperatures and have a risk of hypothermia if they are not kept warm by their mothers.
Many animals other than humans often induce hypothermia during hibernation or torpor.
Water bears (Tardigrade), microscopic multicellular organisms, can survive freezing at low temperatures by replacing most of their internal water with the sugar trehalose, preventing the crystallization that otherwise damages cell membranes. | 0 | Cryobiology |
The desalinated water is stabilized to protect downstream pipelines and storage, usually by adding lime or caustic soda to prevent corrosion of concrete-lined surfaces. Liming material is used to adjust pH between 6.8 and 8.1 to meet the potable water specifications, primarily for effective disinfection and for corrosion control. Remineralisation may be needed to replace minerals removed from the water by desalination, although this process has proved to be costly and inconvenient in order to meet mineral demand by humans and plants as found in typical freshwater. For instance water from Israels national water carrier typically contains dissolved magnesium levels of 20 to 25 mg/liter, while water from the Ashkelon plant has no magnesium. Ashkelon water created magnesium-deficiency symptoms in crops, including tomatoes, basil, and flowers, and had to be remedied by fertilization. Israeli drinking water standards require a minimum calcium level of 20 mg/liter. Askelons post-desalination treatment uses sulfuric acid to dissolve calcite (limestone), resulting in calcium concentrations of 40 to 46 mg/liter, lower than the 45 to 60 mg/liter found in typical Israeli fresh water. | 1 | Separation Processes |
Some FODMAPs, such as fructose, are readily absorbed in the small intestine of humans via GLUT receptors. Absorption thus depends on the appropriate expression and delivery of these receptors in the intestinal enterocyte to both the apical surface, contacting the lumen of the intestine (e.g., GLUT5), and to the basal membrane, contacting the blood (e.g., GLUT2). Improper absorption of these FODMAPS in the small intestine leaves them available for absorption by gut flora. The resultant metabolism by the gut flora leads to the production of gas and potentially results in bloating and flatulence.
Although FODMAPs can cause certain digestive discomfort in some people, not only do they not cause intestinal inflammation, but they help prevent it because they produce beneficial alterations in the intestinal flora that contribute to maintaining good colon health.
FODMAPs are not the cause of irritable bowel syndrome or other functional gastrointestinal disorders, but rather a person develops symptoms when the underlying bowel response is exaggerated or abnormal.
Fructose malabsorption and lactose intolerance may produce IBS symptoms through the same mechanism, but unlike other FODMAPs, poor absorption of fructose is found in only a minority of people. Lactose intolerance is found in most adults, except for specific geographic populations, notably those of European descent. Many who benefit from a low FODMAP diet need not restrict fructose or lactose. It is possible to identify these two conditions with hydrogen and methane breath testing, thus eliminating the necessity for dietary compliance. | 2 | Carbohydrates |
The Zeeman energy is the interaction energy between the magnetization and any externally applied field. It's written as:
where H is the applied field and µ is the vacuum permeability.
The Zeeman energy favors alignment of the magnetization parallel to the applied field. | 3 | Magnetic Ordering |
AFPs create a difference between the melting point and freezing point (busting temperature of AFP bound ice crystal) known as thermal hysteresis. The addition of AFPs at the interface between solid ice and liquid water inhibits the thermodynamically favored growth of the ice crystal. Ice growth is kinetically inhibited by the AFPs covering the water-accessible surfaces of ice.
Thermal hysteresis is easily measured in the lab with a nanolitre osmometer. Organisms differ in their values of thermal hysteresis. The maximum level of thermal hysteresis shown by fish AFP is approximately −3.5 °C (Sheikh Mahatabuddin et al., SciRep)(29.3 °F). In contrast, aquatic organisms are exposed only to −1 to −2 °C below freezing. During the extreme winter months, the spruce budworm resists freezing at temperatures approaching −30 °C.
The rate of cooling can influence the thermal hysteresis value of AFPs. Rapid cooling can substantially decrease the nonequilibrium freezing point, and hence the thermal hysteresis value. Consequently, organisms cannot necessarily adapt to their subzero environment if the temperature drops abruptly. | 0 | Cryobiology |
Spinning band distillation may sometimes be used to recycle waste solvents which contain different solvents, and other chemical compounds. | 1 | Separation Processes |
This is similar to the Ising model. In this model, we have spins arranged on a -dimensional lattice with only nearest neighbor interactions. This model can be solved exactly for the critical temperatures and a glassy phase is observed to exist at low temperatures. The Hamiltonian for this spin system is given by:
where refers to the Pauli spin matrix for the spin-half particle at lattice point , and the sum over refers to summing over neighboring lattice points and . A negative value of denotes an antiferromagnetic type interaction between spins at points and . The sum runs over all nearest neighbor positions on a lattice, of any dimension. The variables representing the magnetic nature of the spin-spin interactions are called bond or link variables.
In order to determine the partition function for this system, one needs to average the free energy where , over all possible values of . The distribution of values of is taken to be a Gaussian with a mean and a variance :
Solving for the free energy using the replica method, below a certain temperature, a new magnetic phase called the spin glass phase (or glassy phase) of the system is found to exist which is characterized by a vanishing magnetization along with a non-vanishing value of the two point correlation function between spins at the same lattice point but at two different replicas:
where are replica indices. The order parameter for the ferromagnetic to spin glass phase transition is therefore , and that for paramagnetic to spin glass is again . Hence the new set of order parameters describing the three magnetic phases consists of both and .
Under the assumption of replica symmetry, the mean-field free energy is given by the expression: | 3 | Magnetic Ordering |
Arsenic can sublime readily at high temperatures.
Cadmium and zinc sublime much more than other common materials, so they are not suitable materials for use in vacuum. | 1 | Separation Processes |
Copurification in a chemical or biochemical context is the physical separation by chromatography or other purification technique of two or more substances of interest from other contaminating substances. For substances to co-purify usually implies that these substances attract each other to form a non-covalent complex such as in a protein complex.
However, when fractionating mixtures, especially mixtures containing large numbers of components (for example a cell lysate), it is possible by chance that some components may copurify even though they don't form complexes. In this context the term copurification is sometimes used to denote when two biochemical activities or some other property are isolated together after purification but it is not certain if the sample has been purified to homogeneity (i.e., contains only one molecular species or one molecular complex). Hence these activities or properties are likely but not guaranteed to reside on the same molecule or in the same molecular complex. | 1 | Separation Processes |
AFPs are thought to inhibit ice growth by an adsorption–inhibition mechanism. They adsorb to nonbasal planes of ice, inhibiting thermodynamically-favored ice growth. The presence of a flat, rigid surface in some AFPs seems to facilitate its interaction with ice via Van der Waals force surface complementarity. | 0 | Cryobiology |
* Electronic article surveillance – using magnetostriction to prevent shoplifting
* Magnetostrictive delay lines - an earlier form of computer memory
* Magnetostrictive loudspeakers and headphones | 3 | Magnetic Ordering |
Although menopause is a natural barrier to further conception, IVF has allowed people to be pregnant in their fifties and sixties. People whose uteruses have been appropriately prepared receive embryos that originated from an egg donor. Therefore, although they do not have a genetic link with the child, they have a physical link through pregnancy and childbirth. Even after menopause, the uterus is fully capable of carrying out a pregnancy. | 0 | Cryobiology |
Ultraviolet radiation is invisible to the human eye, but illuminating certain materials with UV radiation causes the emission of visible light, causing these substances to glow with various colors. This is called fluorescence, and has many practical uses. Black lights are required to observe fluorescence, since other types of ultraviolet lamps emit visible light which drowns out the dim fluorescent glow. | 4 | Ultraviolet Radiation |
A protein skimmer or foam fractionator is a device used to remove organic compounds such as food and waste particles from water. It is most commonly used in commercial applications like municipal water treatment facilities, public aquariums, and aquaculture facilities. Smaller protein skimmers are also used for filtration of home saltwater aquariums and even freshwater aquariums and ponds. | 1 | Separation Processes |
In New Zealand, indoor tanning is regulated by a voluntary code of practice. Salons are asked to turn away under-18s, those with type 1 skin (fair skin that burns easily or never tans), people who experienced episodes of sunburn as children, and anyone taking certain medications, with several moles, or who has had skin cancer. Tanners are asked to sign a consent form, which includes health information and advice about the importance of wearing goggles. Surveys have found a high level of non-compliance. The government has carried out bi-annual surveys of tanning facilities since 2012. | 4 | Ultraviolet Radiation |
Ex situ conservation (literally "off-site conservation") is the process of protecting an endangered species, variety or breed, of plant or animal outside its natural habitat. For example, by removing part of the population from a threatened habitat and placing it in a new location, an artificial environment which is similar to the natural habitat of the respective animal and within the care of humans, such as a zoological park or wildlife sanctuary. The degree to which humans control or modify the natural dynamics of the managed population varies widely, and this may include alteration of living environments, reproductive patterns, access to resources, and protection from predation and mortality.
Ex situ management can occur within or outside a species natural geographic range. Individuals maintained ex situ exist outside an ecological niche. This means that they are not under the same selection pressures as wild populations, and they may undergo artificial selection if maintained ex situ' for multiple generations.
Agricultural biodiversity is also conserved in ex situ collections. This is primarily in the form of gene banks where samples are stored in order to conserve the genetic resources of major crop plants and their wild relatives. | 0 | Cryobiology |
Lactulose is useful in treating hyperammonemia (high blood ammonia), which can lead to hepatic encephalopathy. Lactulose helps trap the ammonia (NH) in the colon and bind to it. It does this by using gut flora to acidify the colon, transforming the freely diffusible ammonia into ammonium ions (), which can no longer diffuse back into the blood. It is also useful for preventing hyperammonemia caused as a side effect of administration of valproic acid. | 2 | Carbohydrates |
Ultraviolet radiation is used for very fine resolution photolithography, a procedure wherein a chemical called a photoresist is exposed to UV radiation that has passed through a mask. The exposure causes chemical reactions to occur in the photoresist. After removal of unwanted photoresist, a pattern determined by the mask remains on the sample. Steps may then be taken to "etch" away, deposit on or otherwise modify areas of the sample where no photoresist remains.
Photolithography is used in the manufacture of semiconductors, integrated circuit components, and printed circuit boards. Photolithography processes used to fabricate electronic integrated circuits presently use 193 nm UV and are experimentally using 13.5 nm UV for extreme ultraviolet lithography. | 4 | Ultraviolet Radiation |
UV light can be used to harden particular glues, resins and inks by causing a photochemical reaction inside those substances. This process of hardening is called ‘curing’. UV curing is adaptable to printing, coating, decorating, stereolithography, and in the assembly of a variety of products and materials. In comparison to other technologies, curing with UV energy may be considered a low-temperature process, a high-speed process, and is a solventless process, as cure occurs via direct polymerization rather than by evaporation. Originally introduced in the 1960s, this technology has streamlined and increased automation in many industries in the manufacturing sector. A primary advantage of curing with ultraviolet light is the speed at which a material can be processed. Speeding up the curing or drying step in a process can reduce flaws and errors by decreasing time that an ink or coating spends wet. This can increase the quality of a finished item, and potentially allow for greater consistency. Another benefit to decreasing manufacturing time is that less space needs to be devoted to storing items which can not be used until the drying step is finished.
Because UV energy has unique interactions with many different materials, UV curing allows for the creation of products with characteristics not achievable via other means. This has led to UV curing becoming fundamental in many fields of manufacturing and technology, where changes in strength, hardness, durability, chemical resistance, and many other properties are required. | 4 | Ultraviolet Radiation |
Figure 1 to the right explains the basic principle, in which the organic extractant E is contained inside the pores of a porous particle. The solute S, which is initially dissolved in the aqueous phase surrounding the SIR particle, physically dissolves in the organic extractant phase during the extraction process. Furthermore, the solute S can react with the extractant to form a complex ES. This complexation of the solute with the extractant shifts the overall extraction equilibrium further towards the organic phase. This way, the extraction of the solute is enhanced.
While during conventional liquid-liquid extraction the solvent and the extractant have to be dispersed, in a SIR setup the dispersion is already achieved by the impregnated particles. This also prevents an additional phase separation step, which would be necessary after the emulsification occurring in liquid-liquid extraction. In order to elucidate the effect of emulsification, Figure 2 (to the left) compares the two systems of an extractant in liquid-liquid equilibrium with water, left, and SIR particles in equilibrium with water, right. The figure shows that no emulsification occurs in the SIR system, whereas the liquid-liquid system shows turbidity implying emulsification. Also, the impregnation step decreases the solvent loss into the aqueous phase compared to liquid-liquid extraction. This decrease of extractant loss is contributed to physical sorption of the extractant on the particle surface, which means that the extractant inside the pores does not entirely behave as a bulk liquid. Depending on the pore size of the used particles, capillary forces may also play a role in retaining the extractant. Otherwise, van-der-Waals forces, pi-pi-interactions or hydrophobic interactions might stabilize the extractant inside the particle pores. However, the possible decrease of extractant loss depends largely on the pore size and the water solubility of the extractant. Nonetheless, SIRs have a significant advantage over e.g. custom made ion-exchange resins with chemically bonded ligands. SIRs can be reused for different separation tasks by just rinsing one complexing agent out and re-impregnating them with another more suitable extractant. This way, potentially expensive design and production steps of e.g. affinity resins can be avoided. Finally, by filling the whole volume of the particle pores with an extractant (complexing agent), a higher capacity for solutes can be achieved than with ordinary adsorption or ion exchange resins, where only the surface area is available.
However, there are possible drawbacks of SIR technology, such as leaching of the extractant or clogging of a fixed bed by attrition of the particles. These might be remedied by choosing the proper particle-extractant-system. This implies selecting a suitable extractant with low water solubility, which is sufficiently retained inside the pores, and selecting mechanically stable particles as a solid support for the extractant. Additionally, SIRs can be stabilized by coating them, as shown by D. Muraviev et al. As coating material, A. W. Trochimczuk et al. used polyvinyl alcohol.
In order to remove or recover the extracted solute, SIR particles can be regenerated using low pressure steam stripping, which is particularly effective for the recovery of volatile hydrocarbons. However, if the vapor pressure of the extracted solute is too low, or if the complexation between solute and extractant is too strong, other techniques need to be applied, e.g. pH swing. | 1 | Separation Processes |
Depending upon the desired product, either the solvent or solute stream of RO will be waste. For food concentration applications, the concentrated solute stream is the product and the solvent stream is waste. For water treatment applications, the solvent stream is purified water and the solute stream is concentrated waste. The solvent waste stream from food processing may be used as reclaimed water, but there may be fewer options for disposal of a concentrated waste solute stream. Ships may use marine dumping and coastal desalination plants typically use marine outfalls. Landlocked RO plants may require evaporation ponds or injection wells to avoid polluting groundwater or surface runoff. | 1 | Separation Processes |
The magnetocrystalline anisotropy energy is generally represented as an expansion in powers of the direction cosines of the magnetization. The magnetization vector can be written , where is the saturation magnetization. Because of time reversal symmetry, only even powers of the cosines are allowed. The nonzero terms in the expansion depend on the crystal system (e.g., cubic or hexagonal). The order of a term in the expansion is the sum of all the exponents of magnetization components, e.g., is second order. | 3 | Magnetic Ordering |
Dr. Kenneth B. Storey is among the top 2% of highly cited scientists in the world.
*[https://pubmed.ncbi.nlm.nih.gov/?term=storey+kb&sort=date&size=100 PubMed]
* [https://scholar.google.com/citations?user=mzhKxEoAAAAJ&hl=en Google Scholar] | 0 | Cryobiology |
Numerous fields would be able to benefit from the protection of tissue damage by freezing. Businesses are currently investigating the use of these proteins in:
* Increasing freeze tolerance of crop plants and extending the harvest season in cooler climates
* Improving farm fish production in cooler climates
* Lengthening shelf life of frozen foods
* Improving cryosurgery
* Enhancing preservation of tissues for transplant or transfusion in medicine
* Therapy for hypothermia
* Human Cryopreservation (Cryonics)
Unilever has obtained UK, US, EU, Mexico, China, Philippines, Australia and New Zealand approval to use a genetically modified yeast to produce antifreeze proteins from fish for use in ice cream production. They are labeled "ISP" or ice structuring protein on the label, instead of AFP or antifreeze protein. | 0 | Cryobiology |
This method is related to the downdraft, but uses a pump to power a spray nozzle, fixed a few inches above the water level. The spray action entraps and shreds the air in the base of the unit, similar to holding your thumb over a garden hose, which then rises to the collection chamber. In the United States, one company has patented the spray induction technology and the commercial product offerings are limited to that single company. | 1 | Separation Processes |
Micromagnetics as a field (i.e., that deals specifically with the behaviour of ferromagnetic materials at sub-micrometer length scales) was introduced in 1963 when William Fuller Brown Jr. published a paper on antiparallel domain wall structures. Until comparatively recently computational micromagnetics has been prohibitively expensive in terms of computational power, but smaller problems are now solvable on a modern desktop PC. | 3 | Magnetic Ordering |
In fact, magnetostriction is more complex and depends on the direction of the crystal axes. In iron, the [100] axes are the directions of easy magnetization, while there is little magnetization along the [111] directions (unless the magnetization becomes close to the saturation magnetization, leading to the change of the domain orientation from [111] to [100]). This magnetic anisotropy pushed authors to define two independent longitudinal magnetostrictions and .
* In cubic materials, the magnetostriction along any axis can be defined by a known linear combination of these two constants. For instance, the elongation along [110] is a linear combination of and .
* Under assumptions of isotropic magnetostriction (i.e. domain magnetization is the same in any crystallographic directions), then and the linear dependence between the elastic energy and the stress is conserved, . Here, , and are the direction cosines of the domain magnetization, and , , those of the bond directions, towards the crystallographic directions. | 3 | Magnetic Ordering |
The first successful birth of a child after IVF treatment, Louise Brown, occurred in 1978. Louise Brown was born as a result of natural cycle IVF where no stimulation was made. The procedure took place at Dr Kershaws Cottage Hospital (now Dr Kershaws Hospice) in Royton, Oldham, England. Robert G. Edwards, the physiologist who co-developed the treatment, was awarded the Nobel Prize in Physiology or Medicine in 2010. His co-workers, Patrick Steptoe and Jean Purdy, were not eligible for consideration as the Nobel Prize is not awarded posthumously.
The second successful birth of a test tube baby occurred in India just 67 days after Louise Brown was born. The girl, named Durga, was conceived in vitro using a method developed independently by Subhash Mukhopadhyay, a physician and researcher from Hazaribag. Mukhopadhyay had been performing experiments on his own with primitive instruments and a household refrigerator. However, state authorities prevented him from presenting his work at scientific conferences, and it was many years before Mukhopadhyay's contribution was acknowledged in works dealing with the subject.
Adriana Iliescu held the record as the oldest woman to give birth using IVF and a donor egg, when she gave birth in 2004 at the age of 66, a record passed in 2006. After the IVF treatment some couples are able to get pregnant without any fertility treatments. In 2018 it was estimated that eight million children had been born worldwide using IVF and other assisted reproduction techniques. | 0 | Cryobiology |
Different sources include different members in this class. Members marked with a "#" are considered by MeSH to be glucosidases. | 2 | Carbohydrates |
A separation process is a method that converts a mixture or a solution of chemical substances into two or more distinct product mixtures, a scientific process of separating two or more substances in order to obtain purity. At least one product mixture from the separation is enriched in one or more of the source mixture's constituents. In some cases, a separation may fully divide the mixture into pure constituents. Separations exploit differences in chemical properties or physical properties (such as size, shape, mass, density, or chemical affinity) between the constituents of a mixture.
Processes are often classified according to the particular properties they exploit to achieve separation. If no single difference can be used to accomplish the desired separation, multiple operations can often be combined to achieve the desired end.
With a few exceptions, elements or compounds exist in nature in an impure state. Often these raw materials must go through a separation before they can be put to productive use, making separation techniques essential for the modern industrial economy.
The purpose of separation may be:
* analytical: to identify the size of each fraction of a mixture is attributable to each component without attempting to harvest the fractions.
* preparative: to "prepare" fractions for input into processes that benefit when components are separated.
Separations may be performed on a small scale, as in a laboratory for analytical purposes, or on a large scale, as in a chemical plant. | 1 | Separation Processes |
The approximate knife advance rate can be determined for a set of operating conditions using table 6 below. The table indicates the number of hours that the filter can operate in a one-inch pre coat cake; the required condition is that the advance blade must be at a constant position. This method can be used to check for optimum operation range.
If the operating parameter is higher than the optimum range, the user can reduce the knife advance rate and use a tighter grade of filter aid. This will result in less filter aid used (lower capital cost) and less filter aid being removed (lower disposal cost). However, if the operating parameter is lower than the optimum range, the user can increase the knife advanced rate (more production) and decrease the drum speed for less filter air usage (reduced operating cost). | 1 | Separation Processes |
An article published in Nature Materials demonstrated cell efficiencies of 8.2% using a new solvent-free liquid redox electrolyte consisting of a melt of three salts, as an alternative to using organic solvents as an electrolyte solution. Although the efficiency with this electrolyte is less than the 11% being delivered using the existing iodine-based solutions, the team is confident the efficiency can be improved. | 4 | Ultraviolet Radiation |
The magnetostriction characterizes the shape change of a ferromagnetic material during magnetization, whereas the inverse magnetostrictive effect characterizes the change of sample magnetization (for given magnetizing field strength ) when mechanical stresses are applied to the sample. | 3 | Magnetic Ordering |
A spin chain is a type of model in statistical physics. Spin chains were originally formulated to model magnetic systems, which typically consist of particles with magnetic spin located at fixed sites on a lattice. A prototypical example is the quantum Heisenberg model. Interactions between the sites are modelled by operators which act on two different sites, often neighboring sites.
They can be seen as a quantum version of statistical lattice models, such as the Ising model, in the sense that the parameter describing the spin at each site is promoted from a variable taking values in a discrete set (typically , representing spin up and spin down) to a variable taking values in a vector space (typically the spin-1/2 or two-dimensional representation of ). | 3 | Magnetic Ordering |
When an external magnetic field H is applied to an assembly of superparamagnetic nanoparticles, their magnetic moments tend to align along the applied field, leading to a net magnetization. The magnetization curve of the assembly, i.e. the magnetization as a function of the applied field, is a reversible S-shaped increasing function. This function is quite complicated but for some simple cases:
# If all the particles are identical (same energy barrier and same magnetic moment), their easy axes are all oriented parallel to the applied field and the temperature is low enough (T < T ≲ KV/(10 k)), then the magnetization of the assembly is
# If all the particles are identical and the temperature is high enough (T ≳ KV/k), then, irrespective of the orientations of the easy axes:
In the above equations:
* n is the density of nanoparticles in the sample
* is the magnetic permeability of vacuum
* is the magnetic moment of a nanoparticle
* is the Langevin function
The initial slope of the function is the magnetic susceptibility of the sample :
The latter susceptibility is also valid for all temperatures if the easy axes of the nanoparticles are randomly oriented.
It can be seen from these equations that large nanoparticles have a larger µ and so a larger susceptibility. This explains why superparamagnetic nanoparticles have a much larger susceptibility than standard paramagnets: they behave exactly as a paramagnet with a huge magnetic moment. | 3 | Magnetic Ordering |
In condensed matter physics, altermagnetism is a type of persistent magnetic state in ideal crystals. Altermagnetic structures are collinear and crystal-symmetry compensated, resulting in zero net magnetisation. Unlike in an ordinary collinear antiferromagnet, another magnetic state with zero net magnetization, the electronic bands in an altermagnet are not Kramers degenerate, but instead depend on the wavevector in a spin-dependent way. Related to this feature, key experimental observations
were published in 2024. It has been speculated that altermagnetism may have applications in the field of spintronics. | 3 | Magnetic Ordering |
Distillation is a process in which we separate components of different vapour pressure. One fraction leaves overhead and is condensed to distillate and the other is the bottom product. The bottom product is mostly liquid while the overhead fraction can be vapour or an aerosol.
This method requires the components to have different volatility to be separated.
The column consists of three sections: a stripping section, a rectification section, and a feed section.
For rectification and stripping a countercurrent liquid phase must flow through the column, so that liquid and vapour can contact each other on each stage.
The distillation column is fed with a mixture containing the mole fraction xf of the desired compound. The overhead mixture is a gas or an aerosol which contains the mole fraction xD of the desired compound and the bottom product contains a mixture with the fraction xB of the desired compound.
An overhead condenser is a heat exchange equipment used for condensing the mixture leaving the top of the column. Either cooling water or air is used as a cooling agent.
An overhead accumulator is a horizontal pressure vessel containing the condensed mixture.
Pumps can be used to control the reflux to the column.
A Reboiler produces the vapour stream in the distillation column. It can be used internally and externally. | 1 | Separation Processes |
Five biosynthesis pathways have been reported for trehalose. The most common pathway is TPS/TPP pathway which is used by organisms that synthesize trehalose using the enzyme trehalose-6-phosphate (T6P) synthase (TPS). Second, trehalose synthase (TS) in certain types of bacteria could produce trehalose by using maltose and another disaccharide with two glucose units as substrates. Third, the TreY-TreZ pathway in some bacteria converts starch that contain maltooligosaccharide or glycogen directly into trehalose. Fourth, in primitive bacteria, trehalose glycisyltransferring synthase (TreT) produces trehalose from ADP-glucose and glucose. Fifth, trehalose phosphorylase (TreP) either hydrolyses trehalose into glucose-1-phosphate and glucose or may act reversibly in certain species. Vertebrates do not have the ability to synthesize or store trehalose. Trehalase in humans is found only in specific location such as the intestinal mucosa, renal brush-border, liver and blood. Expression of this enzyme in vertebrates is initially found during the gestation period that is the highest after weaning. Then, the level of trehalase remained constant in the intestine throughout life. Meanwhile, diets consisting of plants and fungi contain trehalose. Moderate amount of trehalose in diet is essential and having low amount of trehalose could result in diarrhea, or other intestinal symptoms. | 2 | Carbohydrates |
Ferrimagnetism has the same physical origins as ferromagnetism and antiferromagnetism. In ferrimagnetic materials the magnetization is also caused by a combination of dipole–dipole interactions and exchange interactions resulting from the Pauli exclusion principle. The main difference is that in ferrimagnetic materials there are different types of atoms in the material's unit cell. An example of this can be seen in the figure above. Here the atoms with a smaller magnetic moment point in the opposite direction of the larger moments. This arrangement is similar to that present in antiferromagnetic materials, but in ferrimagnetic materials the net moment is nonzero because the opposed moments differ in magnitude.
Ferrimagnets have a critical temperature above which they become paramagnetic just as ferromagnets do. At this temperature (called the Curie temperature) there is a second-order phase transition, and the system can no longer maintain a spontaneous magnetization. This is because at higher temperatures the thermal motion is strong enough that it exceeds the tendency of the dipoles to align. | 3 | Magnetic Ordering |
Sublimation is the transition of a substance directly from the solid to the gas state, without passing through the liquid state. The verb form of sublimation is sublime, or less preferably, sublimate. Sublimate also refers to the product obtained by sublimation. The point at which sublimation occurs rapidly (for further details, see below) is called critical sublimation point, or simply sublimation point. Notable examples include sublimation of dry ice at room temperature and atmospheric pressure, and that of solid iodine with heating.
The reverse process of sublimation is deposition (also called desublimation), in which a substance passes directly from a gas to a solid phase, without passing through the liquid state.
All solids sublime, though most sublime at extremely low rates that are hardly detectable. At normal pressures, most chemical compounds and elements possess three different states at different temperatures. In these cases, the transition from the solid to the gas state requires an intermediate liquid state. The pressure referred to is the partial pressure of the substance, not the total (e.g. atmospheric) pressure of the entire system. Thus, any solid can sublime if its vapour pressure is higher than the surrounding partial pressure of the same substance, and in some cases, sublimes at an appreciable rate (e.g. water ice just below 0 °C).
For some substances, such as carbon and arsenic, sublimation from solid state is much more achievable than evaporation from liquid state and it is difficult to obtain them as liquids. This is because the pressure of their triple point in its phase diagram (which corresponds to the lowest pressure at which the substance can exist as a liquid) is very high.
Sublimation is caused by the absorption of heat which provides enough energy for some molecules to overcome the attractive forces of their neighbors and escape into the vapor phase. Since the process requires additional energy, sublimation is an endothermic change. The enthalpy of sublimation (also called heat of sublimation) can be calculated by adding the enthalpy of fusion and the enthalpy of vaporization. | 1 | Separation Processes |
Fusion constructs of a nanobody and TPR-truncated OGT allow for proximity-induced protein-specific O-GlcNAcylation in cells. The nanobody may be directed towards protein tags, e.g., GFP, that are fused to the target protein, or the nanobody may be directed towards endogenous proteins. For example, a nanobody recognizing a C-terminal EPEA sequence can direct OGT enzymatic activity to α-synuclein. | 2 | Carbohydrates |
Ultraviolet radiation (UVR) is part of the electromagnetic spectrum, just beyond visible light. Ultraviolet wavelengths are 100 to 400 nanometres (nm, billionths of a metre) and are divided into three bands: A, B and C. UVA wavelengths are the longest, 315 to 400 nm; UVB are 280 to 315 nm, and UVC wavelengths are the shortest, 100 to 280 nm.
About 95% of the UVR that reaches the earth from the sun is UVA and 5% UVB; no appreciable UVC reaches the earth. While tanning systems before the 1970s produced some UVC, modern tanning devices produce no UVC, a small amount of UVB and mostly UVA. Classified by the WHO as a group 1 carcinogen, UVR has "complex and mixed effects on human health". While it causes skin cancer and other damage, including wrinkles, it also triggers the synthesis of vitamin D and endorphins in the skin. | 4 | Ultraviolet Radiation |
The impact of ultraviolet radiation on human health has implications for the risks and benefits of sun exposure and is also implicated in issues such as fluorescent lamps and health. Getting too much sun exposure can be harmful, but in moderation, sun exposure is beneficial. | 4 | Ultraviolet Radiation |
William C. Boyd alone and then together with Elizabeth Shapleigh introduced the term "lectin" in 1954 from the Latin word lectus, "chosen" (from the verb legere, to choose or pick out). | 2 | Carbohydrates |
Graphene membranes are meant to take advantage of their thinness to increase efficiency. Graphene is a singular layer of carbon atoms, so it is about 1000 times thinner than existing membranes. Graphene membranes are around 100 nm thick while current membranes are about 100 µm. Many researchers were concerned with the durability of graphene and if it would be able to handle RO pressures. New research finds that depending on the substrate (a supporting layer that does no filtration and only provides structural support), graphene membranes can withstand 57MPa of pressure which is about 10 times the typical pressures for seawater RO.
Batch RO may offer increased energy efficiency, more durable equipment and higher salinity limits.
The conventional approach claimed that molecules cross the membrane individually. A research team devised a "solution-friction" theory, claiming that molecules in groups through transient pores. Characterizing that process could guide membrane development. The accepted theory is that individual water molecules diffuse through the membrane, termed the "solution-diffusion" model. | 1 | Separation Processes |
William Thomson (Lord Kelvin) first discovered ordinary magnetoresistance in 1856. He experimented with pieces of iron and discovered that the resistance increases when the current is in the same direction as the magnetic force and decreases when the current is at 90° to the magnetic force. He then did the same experiment with nickel and found that it was affected in the same way but the magnitude of the effect was greater. This effect is referred to as anisotropic magnetoresistance (AMR).
In 2007, Albert Fert and Peter Grünberg were jointly awarded the Nobel Prize for the discovery of giant magnetoresistance. | 3 | Magnetic Ordering |
Dysregulation of O-GlcNAc is associated with cancer cell proliferation and tumor growth.
O-GlcNAcylation of the glycolytic enzyme PFK1 at S529 has been found to inhibit PFK1 enzymatic activity, reducing glycolytic flux and redirecting glucose towards the pentose phosphate pathway. Structural modeling and biochemical experiments suggested that O-GlcNAc at S529 would inhibit PFK1 allosteric activation by fructose 2,6-bisphosphate and oligomerization into active forms. In a mouse model, mice injected with cells expressing PFK1 S529A mutant showed lower tumor growth than mice injected with cells expressing PFK1 wild-type. Additionally, OGT overexpression enhanced tumor growth in the latter system but had no significant effect on the system with mutant PFK1. Hypoxia induces PFK1 S529 O-GlcNAc and increases flux through the pentose phosphate pathway to generate more NADPH, which maintains glutathione levels and detoxifies reactive oxygen species, imparting a growth advantage to cancer cells. PFK1 was found to be glycosylated in human breast and lung tumor tissues. OGT has also been reported to positively regulate HIF-1α. HIF-1α is normally degraded under normoxic conditions by prolyl hydroxylases that utilize α-ketoglutarate as a co-substrate. OGT suppresses α-ketoglutarate levels, protecting HIF-1α from proteasomal degradation by pVHL and promoting aerobic glycolysis. In contrast with the previous study on PFK1, this study found that elevating OGT or O-GlcNAc upregulated PFK1, though the two studies are consistent in finding that O-GlcNAc levels are positively associated with flux through the pentose phosphate pathway. This study also found that decreasing O-GlcNAc selectively killed cancer cells via ER stress-induced apoptosis.
Human pancreatic ductal adenocarcinoma (PDAC) cell lines have higher O-GlcNAc levels than human pancreatic duct epithelial (HPDE) cells. PDAC cells have some dependency upon O-GlcNAc for survival as OGT knockdown selectively inhibited PDAC cell proliferation (OGT knockdown did not significantly affect HPDE cell proliferation), and inhibition of OGT with 5S-GlcNAc showed the same result. Hyper-O-GlcNAcylation in PDAC cells appeared to be anti-apoptotic, inhibiting cleavage and activation of caspase-3 and caspase-9. Numerous sites on the p65 subunit of NF-κB were found to be modified by O-GlcNAc in a dynamic manner; O-GlcNAc at p65 T305 and S319 in turn positively regulate other modifications associated with NF-κB activation such as p300-mediated K310 acetylation and IKK-mediated S536 phosphorylation. These results suggested that NF-κB is constitutively activated by O-GlcNAc in pancreatic cancer.
OGT stabilization of EZH2 in various breast cancer cell lines has been found to inhibit expression of tumor suppressor genes. In hepatocellular carcinoma models, O-GlcNAc is associated with activating phosphorylation of HDAC1, which in turn regulates expression of the cell cycle regulator p21 and cell motility regulator E-cadherin.
OGT has been found to stabilize SREBP-1 and activate lipogenesis in breast cancer cell lines. This stabilization was dependent on the proteasome and AMPK. OGT knockdown resulted in decreased nuclear SREBP-1, but proteasomal inhibition with MG132 blocked this effect. OGT knockdown also increased the interaction between SREBP-1 and the E3 ubiquitin ligase FBW7. AMPK is activated by T172 phosphorylation upon OGT knockdown, and AMPK phosphorylates SREBP-1 S372 to inhibit its cleavage and maturation. OGT knockdown had a diminished effect on SREBP-1 levels in AMPK-null cell lines. In a mouse model, OGT knockdown inhibited tumor growth but SREBP-1 overexpression partly rescued this effect. These results contrast from those of a previous study which found that OGT knockdown/inhibition inhibited AMPK T172 phosphorylation and increased lipogenesis.
In breast and prostate cancer cell lines, high levels of OGT and O-GlcNAc have been associated both in vitro and in vivo with processes associated with disease progression, e.g., angiogenesis, invasion, and metastasis. OGT knockdown or inhibition was found to downregulate the transcription factor FoxM1 and upregulate the cell-cycle inhibitor p27 (which is regulated by FoxM1-dependent expression of the E3 ubiquitin ligase component Skp2), causing G1 cell cycle arrest. This appeared to be dependent on proteasomal degradation of FoxM1, as expression of a FoxM1 mutant lacking a degron rescued the effects of OGT knockdown. FoxM1 was found not to be directly modified by O-GlcNAc, suggesting that hyper-O-GlcNAcylation of FoxM1 regulators impairs FoxM1 degradation. Targeting OGT also lowered levels of FoxM1-regulated proteins associated with cancer invasion and metastasis (MMP-2 & MMP-9), and angiogenesis (VEGF). O-GlcNAc modification of cofilin S108 has also been reported to be important for breast cancer cell invasion by regulating cofilin subcellular localization in invadopodia. | 2 | Carbohydrates |
The ozone layer or ozone shield is a region of Earths stratosphere that absorbs most of the Suns ultraviolet radiation. It contains a high concentration of ozone (O) in relation to other parts of the atmosphere, although still small in relation to other gases in the stratosphere. The ozone layer contains less than 10 parts per million of ozone, while the average ozone concentration in Earth's atmosphere as a whole is about 0.3 parts per million. The ozone layer is mainly found in the lower portion of the stratosphere, from approximately above Earth, although its thickness varies seasonally and geographically.
The ozone layer was discovered in 1913 by French physicists Charles Fabry and Henri Buisson. Measurements of the sun showed that the radiation sent out from its surface and reaching the ground on Earth is usually consistent with the spectrum of a black body with a temperature in the range of , except that there was no radiation below a wavelength of about 310 nm at the ultraviolet end of the spectrum. It was deduced that the missing radiation was being absorbed by something in the atmosphere. Eventually the spectrum of the missing radiation was matched to only one known chemical, ozone. Its properties were explored in detail by the British meteorologist G. M. B. Dobson, who developed a simple spectrophotometer (the Dobsonmeter) that could be used to measure stratospheric ozone from the ground. Between 1928 and 1958, Dobson established a worldwide network of ozone monitoring stations, which continue to operate to this day. The "Dobson unit", a convenient measure of the amount of ozone overhead, is named in his honor.
The ozone layer absorbs 97 to 99 percent of the Sun's medium-frequency ultraviolet light (from about 200 nm to 315 nm wavelength), which otherwise would potentially damage exposed life forms near the surface.
In 1985, atmospheric research revealed that the ozone layer was being depleted by chemicals released by industry, mainly chlorofluorocarbons (CFCs). Concerns that increased UV radiation due to ozone depletion threatened life on Earth, including increased skin cancer in humans and other ecological problems, led to bans on the chemicals, and the latest evidence is that ozone depletion has slowed or stopped. The United Nations General Assembly has designated September 16 as the International Day for the Preservation of the Ozone Layer.
Venus also has a thin ozone layer at an altitude of 100 kilometers above the planet's surface. | 4 | Ultraviolet Radiation |
The following table lists all of the 122 possible three-dimensional magnetic point groups. This is given in the short version of Hermann–Mauguin notation in the following table. Here, the addition of an apostrophe to a symmetry operation indicates that the combination of the symmetry element and the antisymmetry operation is a symmetry of the structure. There are 32 Crystallographic point groups, 32 grey groups, and 58 magnetic point groups.
The magnetic point groups which are compatible with ferromagnetism are colored cyan, the magnetic point groups which are compatible with ferroelectricity are colored red, and the magnetic point groups which are compatible with both ferromagnetism and ferroelectricity are purple. There are 31 magnetic point groups which are compatible with ferromagnetism. These groups, sometimes called admissible, leave at least one component of the spin invariant under operations of the point group. There are 31 point groups compatible with ferroelectricity; these are generalizations of the crystallographic polar point groups. There are also 31 point groups compatible with the theoretically proposed ferrotorodicity. Similar symmetry arguments have been extended to other electromagnetic material properties such as magnetoelectricity or piezoelectricity.
The following diagrams show the stereographic projection of most of the magnetic point groups onto a flat surface. Not shown are the grey point groups, which look identical to the ordinary crystallographic point groups, except they are also invariant under the antisymmetry operation. | 3 | Magnetic Ordering |
Pulses and beans are the main dietary sources (although green beans, canned lentils, sprouted mung beans, tofu (not silken), and tempeh contain comparatively low amounts). Supplements of the enzyme alpha-galactosidase may reduce symptoms, assuming the enzyme product does not contain other FODMAPs, such as polyol artificial sweeteners. | 2 | Carbohydrates |
Intravenous (i.v.) infusion of fructose has been shown to lower phosphorylation potential in liver cells by trapping inorganic phosphate (Pi) as fructose 1-phosphate. The fructokinase reaction occurs quite rapidly in hepatocytes trapping fructose in cells by phosphorylation. On the other hand, the splitting of fructose 1 phosphate to DHAP and glyceraldehyde by Aldolase B is relatively slow. Therefore, fructose-1-phosphate accumulates with the corresponding reduction of intracellular Pi available for phosphorylation reactions in the cell. This is why fructose is contraindicated for total parenteral nutrition (TPN) solutions and is never given intravenously as a source of carbohydrate. It has been suggested that excessive dietary intake of fructose may also result in reduced phosphorylation potential. However, this is still a contentious issue. Dietary fructose is not well absorbed and increased dietary intake often results in malabsorption. Whether or not sufficient amounts of dietary fructose could be absorbed to cause a significant reduction in phosphorylating potential in liver cells remains questionable and there are no clear examples of this in the literature. | 2 | Carbohydrates |
Protein kinases are the enzymes responsible for phosphorylation of serine and threonine residues. O-GlcNAc has been identified on over 100 (~20% of the human kinome) kinases, and this modification is often associated with alterations in kinase activity or kinase substrate scope.
The first report of a kinase being directly regulated by O-GlcNAc was published in 2009. CaMKIV is glycosylated at multiple sites, though S189 was found to be the major site. An S189A mutant was more readily activated by CaMKIV T200 phosphorylation, suggesting that O-GlcNAc at S189 inhibits CaMKIV activity. Homology modeling showed that S189 O-GlcNAc may interfere with ATP binding.
AMPK and OGT are known to modify each other, i.e., AMPK phosphorylates OGT and OGT O-GlcNAcylates AMPK. AMPK activation by AICA ribonucleotide is associated with nuclear localization of OGT in differentiated C2C12 mouse skeletal muscle myotubes, resulting in increased nuclear O-GlcNAc. This effect was not observed in proliferating cells and undifferentiated myoblastic cells. AMPK phosphorylation of OGT T444 has been found to block OGT association with chromatin and decrease H2B S112 O-GlcNAc. Overexpression of GFAT, the enzyme that controls glucose flux into the hexosamine biosynthetic pathway, in mouse adipose tissue has been found to lead to AMPK activation and downstream ACC inhibition and elevated fatty acid oxidation. Glucosamine treatment in cultured 3T3L1 adipocytes showed a similar effect. The exact relationship between O-GlcNAc and AMPK has not been completely elucidated as various studies have reported that OGA inhibition inhibits AMPK activation, OGT inhibition also inhibits AMPK activation, upregulating O-GlcNAc by glucosamine treatment activates AMPK, and OGT knockdown activates AMPK; these results suggest that additional indirect communication between AMPK pathways and O-GlcNAc or cell type-specific effects.
CKIIα substrate recognition has been shown to be altered upon S347 O-GlcNAcylation. | 2 | Carbohydrates |
In general case LLE (2) is nonintegrable. But it admits the two integrable reductions:
: a) in the 1+1 dimensions, that is Eq. (3), it is integrable
: b) when . In this case the (1+1)-dimensional LLE (3) turns into the continuous classical Heisenberg ferromagnet equation (see e.g. Heisenberg model (classical)) which is already integrable. | 3 | Magnetic Ordering |
The integrability is underpinned by the existence of large symmetry algebras for the different models. For the XXX case this is the Yangian , while in the XXZ case this is the quantum group , the q-deformation of the affine Lie algebra of , as explained in the notes by .
These appear through the transfer matrix, and the condition that the Bethe vectors are generated from a state satisfying corresponds to the solutions being part of a highest-weight representation of the extended symmetry algebras. | 3 | Magnetic Ordering |
Corona discharge on electrical apparatus can be detected by its ultraviolet emissions. Corona causes degradation of electrical insulation and emission of ozone and nitrogen oxide.
EPROMs (Erasable Programmable Read-Only Memory) are erased by exposure to UV radiation. These modules have a transparent (quartz) window on the top of the chip that allows the UV radiation in. | 4 | Ultraviolet Radiation |
Managing populations based on minimizing mean kinship values is often an effective way to increase genetic diversity and to avoid inbreeding within captive populations. Kinship is the probability that two alleles will be identical by descent when one allele is taken randomly from each mating individual. The mean kinship value is the average kinship value between a given individual and every other member of the population. Mean kinship values can help determine which individuals should be mated. In choosing individuals for breeding, it is important to choose individuals with the lowest mean kinship values because these individuals are least related to the rest of the population and have the least common alleles. This ensures that rarer alleles are passed on, which helps to increase genetic diversity. It is also important to avoid mating two individuals with very different mean kinship values because such pairings propagate both the rare alleles that are present in the individual with the low mean kinship value as well as the common alleles that are present in the individual with the high mean kinship value. This genetic management technique requires that ancestry is known, so in circumstances where ancestry is unknown, it might be necessary to use molecular genetics such as microsatellite data to help resolve unknowns. | 0 | Cryobiology |
Although the concentration of the ozone in the ozone layer is very small, it is vitally important to life because it absorbs biologically harmful ultraviolet (UV) radiation coming from the Sun. Extremely short or vacuum UV (10–100 nm) is screened out by nitrogen. UV radiation capable of penetrating nitrogen is divided into three categories, based on its wavelength; these are referred to as UV-A (400–315 nm), UV-B (315–280 nm), and UV-C (280–100 nm).
UV-C, which is very harmful to all living things, is entirely screened out by a combination of dioxygen (< 200 nm) and ozone (> about 200 nm) by around altitude. UV-B radiation can be harmful to the skin and is the main cause of sunburn; excessive exposure can also cause cataracts, immune system suppression, and genetic damage, resulting in problems such as skin cancer. The ozone layer (which absorbs from about 200 nm to 310 nm with a maximal absorption at about 250 nm) is very effective at screening out UV-B; for radiation with a wavelength of 290 nm, the intensity at the top of the atmosphere is 350 million times stronger than at the Earths surface. Nevertheless, some UV-B, particularly at its longest wavelengths, reaches the surface, and is important for the skins production of vitamin D in mammals.
Ozone is transparent to most UV-A, so most of this longer-wavelength UV radiation reaches the surface, and it constitutes most of the UV reaching the Earth. This type of UV radiation is significantly less harmful to DNA, although it may still potentially cause physical damage, premature aging of the skin, indirect genetic damage, and skin cancer. | 4 | Ultraviolet Radiation |
CSDB is cross-linked to other glycomics databases, such as [http://www.monosaccharidedb.org MonosaccharideDB], [http://glycosciences.de Glycosciences.DE] , [https://www.ncbi.nlm.nih.gov/pubmed/ NCBI Pubmed], [https://www.ncbi.nlm.nih.gov/taxonomy NCBI Taxonomy], [https://www.ncbi.nlm.nih.gov/nlmcatalog NLM catalog], [https://www.who.int/classifications/icd/en/ International Classification of Diseases 11], etc. Besides a native notation, CSDB Linear, structures are presented in multiple carbohydrate notations (SNFG, SweetDB, GlycoCT, [http://www.wurcs-wg.org WURCS], [http://glycam.org GLYCAM], etc.). CSDB is exportable as a Resource Description Framework (RDF) feed according to the [https://bioportal.bioontology.org/ontologies/GLYCORDF GlycoRDF] ontology. | 2 | Carbohydrates |
As different proteins have different compositions of amino acids, different protein molecules precipitate at different concentrations of salt solution.
Unwanted proteins can be removed from a protein solution mixture by salting out as long as the solubility of the protein in various concentrations of salt solution is known.
After removing the precipitate by filtration or centrifugation, the desired protein can be precipitated by altering the salt concentration to the level at which the desired protein becomes insoluble.
One demerit of salting out in purification of proteins is that, in addition to precipitating a specific protein of interest, contaminants are also precipitated as well. Thus to obtain a purer protein of interest, additional purification methods such as ion exchange chromatography may be required. | 1 | Separation Processes |
The guiding principles for the development of UW Solution were:
# osmotic concentration maintained by the use of metabolically inert substances like lactobionate and raffinose rather than with glucose
# Hydroxyethyl starch (HES) is used to prevent edema
# Substances are added to scavenge free radicals, along with steroids and insulin. | 0 | Cryobiology |
While the definition of sublimation is simple, there is often confusion as to what counts as a sublimation. | 1 | Separation Processes |
People with disabilities who wish to have children are equally or more likely than the non-disabled population to experience infertility, yet disabled individuals are much less likely to have access to fertility treatment such as IVF. There are many extraneous factors that hinder disabled individuals access to IVF, such as assumptions about decision-making capacity, sexual interests and abilities, heritability of a disability, and beliefs about parenting ability. These same misconceptions about people with disabilities that once led health care providers to sterilise thousands of women with disabilities now lead them to provide or deny reproductive care on the basis of stereotypes concerning people with disabilities and their sexuality.
Not only do misconceptions about disabled individuals parenting ability, sexuality, and health restrict and hinder access to fertility treatment such as IVF, structural barriers such as providers uneducated in disability healthcare and inaccessible clinics severely hinder disabled individuals access to receiving IVF. | 0 | Cryobiology |
The belt-type machine is generally more applicable to smaller and to adhesive feed. In addition, the feed presentation is more stable which makes it more applicable for more difficult and heterogenous applications. | 1 | Separation Processes |
Select filter cloth to obtain a good surface for cake formation. Use twill weave variation in the construction pattern of the fabric for better wear resistance. The belt tension, de-mooning bar height, wash water quantity and discharge roll speed are carefully tuned to maintain a good path for the cake formation to prevent excessive wear of the filter cloth. | 1 | Separation Processes |
Matteucci effect is one of the magnetomechanical effects, which is thermodynamically inverse to Wiedemann effect. This effect was described by Carlo Matteucci in 1858. It is observable in amorphous wires with helical domain structure, which can be obtained by twisting the wire, or annealing under twist. The effect is most distinct in the so-called dwarven alloys (called so because of the historical cobalt element etymology), with cobalt as main substituent. | 3 | Magnetic Ordering |
UV degradation is one form of polymer degradation that affects plastics exposed to sunlight. The problem appears as discoloration or fading, cracking, loss of strength or disintegration. The effects of attack increase with exposure time and sunlight intensity. The addition of UV absorbers inhibits the effect.
Sensitive polymers include thermoplastics and speciality fibers like aramids. UV absorption leads to chain degradation and loss of strength at sensitive points in the chain structure. Aramid rope must be shielded with a sheath of thermoplastic if it is to retain its strength.
Many pigments and dyes absorb UV and change colour, so paintings and textiles may need extra protection both from sunlight and fluorescent lamps, two common sources of UV radiation. Window glass absorbs some harmful UV, but valuable artifacts need extra shielding. Many museums place black curtains over watercolour paintings and ancient textiles, for example. Since watercolours can have very low pigment levels, they need extra protection from UV. Various forms of picture framing glass, including acrylics (plexiglass), laminates, and coatings, offer different degrees of UV (and visible light) protection. | 4 | Ultraviolet Radiation |
In 2008, a California physician transferred 12 embryos to a woman who gave birth to octuplets (Suleman octuplets). This led to accusations that a doctor is willing to endanger the health and even life of people in order to gain money. Robert Winston, professor of fertility studies at Imperial College London, had called the industry "corrupt" and "greedy" stating that "one of the major problems facing us in healthcare is that IVF has become a massive commercial industry," and that "what has happened, of course, is that money is corrupting this whole technology", and accused authorities of failing to protect couples from exploitation: "The regulatory authority has done a consistently bad job. Its not prevented the exploitation of people, its not put out very good information to couples, it's not limited the number of unscientific treatments people have access to". The IVF industry has been described as a market-driven construction of health, medicine and the human body.
The industry has been accused of making unscientific claims, and distorting facts relating to infertility, in particular through widely exaggerated claims about how common infertility is in society, in an attempt to get as many couples as possible and as soon as possible to try treatments (rather than trying to conceive naturally for a longer time). This risks removing infertility from its social context and reducing the experience to a simple biological malfunction, which not only can be treated through bio-medical procedures, but should be treated by them. | 0 | Cryobiology |
Besides being a source of energy, few other functions have been described for galactogen in the snail eggs, and all of them are related to embryo defense and protection. Given that carbohydrates retain water, the high amount of this polysaccharide would protect the eggs from desiccation from those snails that have aerial oviposition. Besides, the high viscosity that the polysaccharide may confer to the perivitelline fluid has been suggested as a potential antimicrobial defense.
Since galactogen is a β-linked polysaccharide, such as cellulose or hemicelluloses, specific biochemical adaptations are needed to exploit it as a nutrient, such as specific glycosidases. However, apart from snail embryos and hatchlings, no animal seems to be able to catabolize galactogen, including adult snails. This fact led to consider galactogen as part of an antipredation defense system exclusive of gastropods, deterring predators by lowering the nutritional value of eggs. | 2 | Carbohydrates |
In naphtha cracking process, C4R4 refers to C4 residual obtained after separation of 1,3-butadiene, isobutylene, 1-butene, and cis- or trans-2-butene from C4 raffinate stream which mainly consists of n-butane. Normally C4R4 is a side product in tert-butyl alcohol plant if C4R3 is used for feed. | 1 | Separation Processes |
Most prominent example of the application of sensor-based ore sorting is the rejection of barren waste before transporting and comminution. Waste rejection is also known under the term pre-concentration. A discrimination has been introduced by Robben. Rule of thumb is that at least 25% of liberated barren waste must be present in the fraction to be treated by sensor-based ore sorting to make waste rejection financially feasible.
Reduction of waste before it enters comminution and grinding processes does not only reduce the costs in those processes, but also releases the capacity that can be filled with higher grade material and thus implies higher productivity of the system. A prejudice against the application of a waste rejection process is, that the valuable content lost in this process is a penalty higher than the savings that can be achieved. But it is reported in the literature that the overall recovery even increases through bringing higher grade material as feed into the mill. In addition, the higher productivity is an additional source of income. If noxious waste such as acid consuming calcite is removed, the downstream recovery increases and the downstream costs decrease disproportionally as reported for example by Bergmann. The coarse waste rejected can be an additional source of income if there is a local market for aggregates. | 1 | Separation Processes |
A mixing chamber where a mechanical agitator brings in intimate contact the feed solution and the solvent to carry out the transfer of solute(s). The mechanical agitator is equipped with a motor which drives a mixing and pumping turbine. This turbine draws the two phases from the settlers of the adjacent stages, mixes them, and transfers this emulsion to the associated settler.
The mixer may consists of one or multiple stages of mixing tanks. Common laboratory mixers consist of a single mixing stage, whereas industrial scale copper mixers may consist of up to three mixer stages where each stage performs a combined pumping and mixing action. Use of multiple stages allows a longer reaction time and also minimizes the short circuiting of unreacted material through the mixers. | 1 | Separation Processes |
Often, some amount of hysteresis is intentionally added to an electronic circuit to prevent unwanted rapid switching. This and similar techniques are used to compensate for contact bounce in switches, or noise in an electrical signal.
A Schmitt trigger is a simple electronic circuit that exhibits this property.
A latching relay uses a solenoid to actuate a ratcheting mechanism that keeps the relay closed even if power to the relay is terminated.
Some positive feedback from the output to one input of a comparator can increase the natural hysteresis (a function of its gain) it exhibits.
Hysteresis is essential to the workings of some memristors (circuit components which "remember" changes in the current passing through them by changing their resistance).
Hysteresis can be used when connecting arrays of elements such as nanoelectronics, electrochrome cells and memory effect devices using passive matrix addressing. Shortcuts are made between adjacent components (see crosstalk) and the hysteresis helps to keep the components in a particular state while the other components change states. Thus, all rows can be addressed at the same time instead of individually.
In the field of audio electronics, a noise gate often implements hysteresis intentionally to prevent the gate from "chattering" when signals close to its threshold are applied. | 3 | Magnetic Ordering |
Cold-adapted arctic frogs, such as wood frogs, and some other ectotherms in polar and subpolar regions naturally produce glucose, but southern brown tree frogs and Arctic salamanders create glycerol in their livers to reduce ice formation.
When glucose is used as a cryoprotectant by arctic frogs, massive amounts of glucose are released at low temperature and a special form of insulin allows for this extra glucose to enter the cells. When the frog rewarms during spring, the extra glucose must be rapidly eliminated, but stored. | 0 | Cryobiology |
The reaction is highly regulated by allosteric effectors such as glucose 6-phosphate (activator) and by phosphorylation reactions (deactivating). Glucose-6-phosphate allosteric activating action allows glycogen synthase to operate as a glucose-6-phosphate sensor. The inactivating phosphorylation is triggered by the hormone glucagon, which is secreted by the pancreas in response to decreased blood glucose levels. The enzyme also cleaves the ester bond between the C1 position of glucose and the pyrophosphate of UDP itself.
The control of glycogen synthase is a key step in regulating glycogen metabolism and glucose storage. Glycogen synthase is directly regulated by glycogen synthase kinase 3 (GSK-3), AMPK, protein kinase A (PKA), and casein kinase 2 (CK2). Each of these protein kinases leads to phosphorylated and catalytically inactive glycogen synthase. The phosphorylation sites of glycogen synthase are summarized below.
For enzymes in the GT3 family, these regulatory kinases inactivate glycogen synthase by phosphorylating it at the N-terminal of the 25th residue and the C-terminal of the 120th residue. Glycogen synthase is also regulated by protein phosphatase 1 (PP1), which activates glycogen synthase via dephosphorylation. PP1 is targeted to the glycogen pellet by four targeting subunits, G, G, PTG and R6. These regulatory enzymes are regulated by insulin and glucagon signaling pathways. | 2 | Carbohydrates |
Below are low-FODMAP foods categorized by group according to the Monash University "Low-FODMAP Diet".
* Vegetables: alfalfa, bean sprouts, green beans, bok choy, capsicum (bell pepper), carrot, chives, fresh herbs, choy sum, cucumber, lettuce, tomato, zucchini, the green parts of leeks and spring onions
* Fruits: orange, grapes, honeydew melon (not watermelon)
* Protein: meats, fish, chicken, eggs, tofu (not silken), tempeh
* Dairy: lactose-free milk, lactose-free yoghurts, hard cheese
* Breads and cereals: rice, crisped rice, maize or corn, potatoes, quinoa, and breads made with their flours alone; however, oats and spelt are relatively low in FODMAPs
* Biscuits (cookies) and snacks: made with flour of cereals listed above, without high FODMAP ingredients added (such as onion, pear, honey, or polyol artificial sweeteners)
* Nuts and seeds: almonds (no more than ten nuts per serving), pumpkin seeds; not cashews or pistachios
* Beverage options: water, coffee, tea
Other sources confirm the suitability of these and suggest some additional foods. | 2 | Carbohydrates |
There are a number of non-invasive head cooling caps and helmets designed to target cooling at the brain. A hypothermia cap is typically made of a synthetic material such as neoprene, silicone, or polyurethane and filled with a cooling agent such as ice or gel which is either cooled to a very cold temperature, , before application or continuously cooled by an auxiliary control unit. Their most notable uses are in preventing or reducing alopecia in chemotherapy, and for preventing cerebral palsy in babies born with hypoxic ischemic encephalopathy. In the continuously cooled iteration, coolant is cooled with the aid of a compressor and pumped through the cooling cap. Circulation is regulated by means of valves and temperature sensors in the cap. If the temperature deviates or if other errors are detected, an alarm system is activated. The frozen iteration involves continuous application of caps filled with Crylon gel cooled to to the scalp before, during and after intravenous chemotherapy. As the caps warm on the head, multiple cooled caps must be kept on hand and applied every 20 to 30 minutes. | 0 | Cryobiology |
Insects most often use sugars or polyols as cryoprotectants. One species that uses cryoprotectant is Polistes exclamans (a wasp). In this species, the different levels of cryoprotectant can be used to distinguish between morphologies. | 0 | Cryobiology |
The rotary vacuum drum filter designs available vary in physical aspects and their characteristics. The filtration area ranges from 0.5 m to 125 m. Disregarding the size of the design, filter cloth washing is a priority as it ensures efficiency of cake washing and acting vacuum. However, a smaller design would be more economical as the maintenance, energy usage and investment cost would be less than a bigger rotary vacuum drum filter.
Over the years, the technology drive has pushed development to further heights revolving around rotary vacuum drum filter in terms of design, performance, maintenance and cost. This has also led to the development of smaller rotary drum vacuum filters, ranging from laboratory scale to pilot scale, both of which can be used for smaller applications (such as at a lab in a university) High performance capacity, optimised filtrate drainage with low flow resistance and minimal pressure loss are just a few of the benefits.
With advanced control systems prompting automation, this has reduced the operation of attention needed hence, reducing the operational cost. Advancements in technology also means that precoat can be cut to 1/20th the thickness of human hair, thus making the use of precoat more efficient Lowered operational and capital cost can also be achieved nowadays due to easier maintenance and cleaning. Complete cell emptying can be done quickly with the installation of leading and trailing pipes.
Given that the filter cloth is usually one of the more expensive component in the rotary vacuum drum filter build up, priority on its maintenance must be kept quite high. A longer lifetime, protection from damage and consistent performance are the few criteria that must not be overlooked.
Besides considering production cost and quality, cake washing and cake thickness are essential issues that are important in the process. Methods have been performed to ensure a minimal amount of cake moisture while undergoing good cake washing with large cake dewatering angle. An even thickness of filter cake besides having a complete cake discharge is also possible. | 1 | Separation Processes |
When the periodicity of the magnetic order coincides with the periodicity of crystallographic order, the magnetic phase is said to be commensurate, and can be well-described by a magnetic space group. However, when this is not the case, the order does not correspond to any magnetic space group. These phases can instead be described by magnetic superspace groups, which describe incommensurate order. This is the same formalism often used to describe the ordering of some quasicrystals. | 3 | Magnetic Ordering |
IVF may be used to overcome female infertility when it is due to problems with the fallopian tubes, making in vivo fertilisation difficult. It can also assist in male infertility, in those cases where there is a defect in sperm quality; in such situations intracytoplasmic sperm injection (ICSI) may be used, where a sperm cell is injected directly into the egg cell. This is used when sperm has difficulty penetrating the egg. ICSI is also used when sperm numbers are very low. When indicated, the use of ICSI has been found to increase the success rates of IVF.
According to UK's National Institute for Health and Care Excellence (NICE) guidelines, IVF treatment is appropriate in cases of unexplained infertility for people who have not conceived after 2 years of regular unprotected sexual intercourse.
In people with anovulation, it may be an alternative after 7–12 attempted cycles of ovulation induction, since the latter is expensive and more easy to control. | 0 | Cryobiology |
Normally, ice crystals grown in solution only exhibit the basal (0001) and prism faces (1010), and appear as round and flat discs. However, it appears the presence of AFPs exposes other faces. It now appears the ice surface 2021 is the preferred binding surface, at least for AFP type I. Through studies on type I AFP, ice and AFP were initially thought to interact through hydrogen bonding (Raymond and DeVries, 1977). However, when parts of the protein thought to facilitate this hydrogen bonding were mutated, the hypothesized decrease in antifreeze activity was not observed. Recent data suggest hydrophobic interactions could be the main contributor. It is difficult to discern the exact mechanism of binding because of the complex water-ice interface. Currently, attempts to uncover the precise mechanism are being made through use of molecular modelling programs (molecular dynamics or the Monte Carlo method). | 0 | Cryobiology |
Most liquids freeze by crystallization, formation of crystalline solid from the uniform liquid. This is a first-order thermodynamic phase transition, which means that as long as solid and liquid coexist, the temperature of the whole system remains very nearly equal to the melting point due to the slow removal of heat when in contact with air, which is a poor heat conductor. Because of the latent heat of fusion, the freezing is greatly slowed and the temperature will not drop anymore once the freezing starts but will continue dropping once it finishes.
Crystallization consists of two major events, nucleation and crystal growth. "Nucleation" is the step wherein the molecules start to gather into clusters, on the nanometer scale, arranging in a defined and periodic manner that defines the crystal structure. "Crystal growth" is the subsequent growth of the nuclei that succeed in achieving the critical cluster size. | 0 | Cryobiology |
Spectral and spatial is collected by the detection system. The spatial component catches the position of the particles distribution across the width of the sorting machine, which is then used in case the ejection mechanism is activated for a single particle. Spectral data comprises the features that are used for material discrimination. In a superseding processing step, spectral and spatial can be combined to include patterns into the separation criterion. Huge amount of data is collected in real time multiple processing and filtering steps are bringing the data down to the Yes/no decision – either for ejecting a particle or for keeping the ejection mechanism still for that one. | 1 | Separation Processes |
Endangered animal species and breeds are preserved using similar techniques. Animal species can be preserved in genebanks, which consist of cryogenic facilities used to store living sperm, eggs, or embryos. For example, the Zoological Society of San Diego has established a "frozen zoo" to store such samples using cryopreservation techniques from more than 355 species, including mammals, reptiles, and birds.
A potential technique for aiding in reproduction of endangered species is interspecific pregnancy, implanting embryos of an endangered species into the womb of a female of a related species, carrying it to term. It has been carried out for the Spanish ibex. | 0 | Cryobiology |
In the elastic hysteresis of rubber, the area in the centre of a hysteresis loop is the energy dissipated due to material internal friction.
Elastic hysteresis was one of the first types of hysteresis to be examined.
The effect can be demonstrated using a rubber band with weights attached to it. If the top of a rubber band is hung on a hook and small weights are attached to the bottom of the band one at a time, it will stretch and get longer. As more weights are loaded onto it, the band will continue to stretch because the force the weights are exerting on the band is increasing. When each weight is taken off, or unloaded, the band will contract as the force is reduced. As the weights are taken off, each weight that produced a specific length as it was loaded onto the band now contracts less, resulting in a slightly longer length as it is unloaded. This is because the band does not obey Hooke's law perfectly. The hysteresis loop of an idealized rubber band is shown in the figure.
In terms of force, the rubber band was harder to stretch when it was being loaded than when it was being unloaded. In terms of time, when the band is unloaded, the effect (the length) lagged behind the cause (the force of the weights) because the length has not yet reached the value it had for the same weight during the loading part of the cycle. In terms of energy, more energy was required during the loading than the unloading, the excess energy being dissipated as thermal energy.
Elastic hysteresis is more pronounced when the loading and unloading is done quickly than when it is done slowly. Some materials such as hard metals don't show elastic hysteresis under a moderate load, whereas other hard materials like granite and marble do. Materials such as rubber exhibit a high degree of elastic hysteresis.
When the intrinsic hysteresis of rubber is being measured, the material can be considered to behave like a gas. When a rubber band is stretched it heats up, and if it is suddenly released, it cools down perceptibly. These effects correspond to a large hysteresis from the thermal exchange with the environment and a smaller hysteresis due to internal friction within the rubber. This proper, intrinsic hysteresis can be measured only if the rubber band is thermally isolated.
Small vehicle suspensions using rubber (or other elastomers) can achieve the dual function of springing and damping because rubber, unlike metal springs, has pronounced hysteresis and does not return all the absorbed compression energy on the rebound. Mountain bikes have made use of elastomer suspension, as did the original Mini car.
The primary cause of rolling resistance when a body (such as a ball, tire, or wheel) rolls on a surface is hysteresis. This is attributed to the viscoelastic characteristics of the material of the rolling body. | 3 | Magnetic Ordering |
Accurate determination of core temperature often requires a special low temperature thermometer, as most clinical thermometers do not measure accurately below . A low temperature thermometer can be placed in the rectum, esophagus or bladder. Esophageal measurements are the most accurate and are recommended once a person is intubated. Other methods of measurement such as in the mouth, under the arm, or using an infrared ear thermometer are often not accurate.
As a hypothermic person's heart rate may be very slow, prolonged feeling for a pulse could be required before detecting. In 2005, the American Heart Association recommended at least 30–45 seconds to verify the absence of a pulse before initiating CPR. Others recommend a 60-second check.
The classical ECG finding of hypothermia is the Osborn J wave. Also, ventricular fibrillation frequently occurs below and asystole below . The Osborn J may look very similar to those of an acute ST elevation myocardial infarction. Thrombolysis as a reaction to the presence of Osborn J waves is not indicated, as it would only worsen the underlying coagulopathy caused by hypothermia. | 0 | Cryobiology |
In Egypt around 2000 BC, the juice of Ammi majus was rubbed on patches of vitiligo after which patients were encouraged to lie in the sun. In the 13th century, vitiligo was treated with a tincture of honey and the powdered seeds of a plant called "aatrillal", which was abundant in the Nile Valley. The plant has since been identified as A. majus, which contains significant amounts of both bergapten and methoxsalen, two psoralen derivatives well known for their photosensitizing effects.
In the 1890s Niels Ryberg Finsen of Copenhagen developed a bulky phototherapy machine to treat skin diseases using UV light. In 1900, the French electrical engineer Gustave Trouvé miniaturized Finsen's machine with a series of portable light radiators to heal skin diseases such as lupus and epithelioma. Such machines have only been available in a chemically synthesized form since the 1970s.
In the 1940s, Abdel Monem El Mofty from Cairo University Medical School used crystalline methoxsalen (8-methoxypsoralen, also called xanthotoxin) followed by sunlight exposure to treat vitiligo. This began the development of modern PUVA therapy for the treatment of vitiligo, psoriasis, and other diseases of the skin. | 4 | Ultraviolet Radiation |
Animal studies have shown the benefit of targeted temperature management in traumatic central nervous system (CNS) injuries. Clinical trials have shown mixed results with regards to the optimal temperature and delay of cooling. Achieving therapeutic temperatures of is thought to prevent secondary neurological injuries after severe CNS trauma. A systematic review of randomised controlled trials in traumatic brain injury (TBI) suggests there is no evidence that hypothermia is beneficial. | 0 | Cryobiology |
Hypothermia has been applied therapeutically since antiquity. The Greek physician Hippocrates, the namesake of the Hippocratic Oath, advocated the packing of wounded soldiers in snow and ice. Napoleonic surgeon Baron Dominique Jean Larrey recorded that officers who were kept closer to the fire survived less often than the minimally pampered infantrymen. In modern times, the first medical article concerning hypothermia was published in 1945. This study focused on the effects of hypothermia on patients with severe head injury. In the 1950s, hypothermia received its first medical application, being used in intracerebral aneurysm surgery to create a bloodless field. Most of the early research focused on the applications of deep hypothermia, defined as a body temperature of . Such an extreme drop in body temperature brings with it a whole host of side effects, which made the use of deep hypothermia impractical in most clinical situations.
This period also saw sporadic investigation of more mild forms of hypothermia, with mild hypothermia being defined as a body temperature of . In the 1950s, Doctor Rosomoff demonstrated in dogs the positive effects of mild hypothermia after brain ischemia and traumatic brain injury. In the 1980s further animal studies indicated the ability of mild hypothermia to act as a general neuroprotectant following a blockage of blood flow to the brain. This animal data was supported by two landmark human studies that were published simultaneously in 2002 by the New England Journal of Medicine. Both studies, one occurring in Europe and the other in Australia, demonstrated the positive effects of mild hypothermia applied following cardiac arrest. Responding to this research, in 2003 the American Heart Association (AHA) and the International Liaison Committee on Resuscitation (ILCOR) endorsed the use of targeted temperature management following cardiac arrest. Currently, a growing percentage of hospitals around the world incorporate the AHA/ILCOR guidelines and include hypothermic therapies in their standard package of care for patients with cardiac arrest. Some researchers go so far as to contend that hypothermia represents a better neuroprotectant following a blockage of blood to the brain than any known drug. Over this same period a particularly successful research effort showed that hypothermia is a highly effective treatment when applied to newborn infants following birth asphyxia. Meta-analysis of a number of large randomised controlled trials showed that hypothermia for 72 hours started within 6 hours of birth significantly increased the chance of survival without brain damage. | 0 | Cryobiology |
UV light (specifically, UV‑B) causes the body to produce vitamin D, which is essential for life. Humans need some UV radiation to maintain adequate vitamin D levels. According to the World Health Organization:
Vitamin D can also be obtained from food and supplementation. Excess sun exposure produces harmful effects, however.
Vitamin D promotes the creation of serotonin. The production of serotonin is in direct proportion to the degree of bright sunlight the body receives. Serotonin is thought to provide sensations of happiness, well-being and serenity to human beings. | 4 | Ultraviolet Radiation |
Patients usually start progesterone medication after egg (also called oocyte) retrieval. While daily intramuscular injections of progesterone-in-oil (PIO) have been the standard route of administration, PIO injections are not FDA-approved for use in pregnancy. A recent meta-analysis showed that the intravaginal route with an appropriate dose and dosing frequency is equivalent to daily intramuscular injections. In addition, a recent case-matched study comparing vaginal progesterone with PIO injections showed that live birth rates were nearly identical with both methods. A duration of progesterone administration of 11 days results in almost the same birth rates as longer durations.
Patients are also given estrogen medication in some cases after the embryo transfer. Pregnancy testing is done typically two weeks after egg retrieval. | 0 | Cryobiology |
A review in 2013 came to the result that infants resulting from IVF (with or without ICSI) have a relative risk of birth defects of 1.32 (95% confidence interval 1.24–1.42) compared to naturally conceived infants. In 2008, an analysis of the data of the National Birth Defects Study in the US found that certain birth defects were significantly more common in infants conceived through IVF, notably septal heart defects, cleft lip with or without cleft palate, esophageal atresia, and anorectal atresia; the mechanism of causality is unclear. However, in a population-wide cohort study of 308,974 births (with 6,163 using assisted reproductive technology and following children from birth to age five) researchers found: "The increased risk of birth defects associated with IVF was no longer significant after adjustment for parental factors." Parental factors included known independent risks for birth defects such as maternal age, smoking status, etc. Multivariate correction did not remove the significance of the association of birth defects and ICSI (corrected odds ratio 1.57), although the authors speculate that underlying male infertility factors (which would be associated with the use of ICSI) may contribute to this observation and were not able to correct for these confounders. The authors also found that a history of infertility elevated risk itself in the absence of any treatment (odds ratio 1.29), consistent with a Danish national registry study and "implicates patient factors in this increased risk." The authors of the Danish national registry study speculate: "our results suggest that the reported increased prevalence of congenital malformations seen in singletons born after assisted reproductive technology is partly due to the underlying infertility or its determinants." | 0 | Cryobiology |
There is some evidence that T cells exhibit hysteresis in that it takes a lower signal threshold to activate T cells that have been previously activated. Ras GTPase activation is required for downstream effector functions of activated T cells. Triggering of the T cell receptor induces high levels of Ras activation, which results in higher levels of GTP-bound (active) Ras at the cell surface. Since higher levels of active Ras have accumulated at the cell surface in T cells that have been previously stimulated by strong engagement of the T cell receptor, weaker subsequent T cell receptor signals received shortly afterwards will deliver the same level of activation due to the presence of higher levels of already activated Ras as compared to a naïve cell. | 3 | Magnetic Ordering |
The physics of the Heisenberg XXX model strongly depends on the sign of the coupling constant
and the dimension of the space. For positive the ground state is always ferromagnetic. At negative the ground state is antiferromagnetic in two and three dimensions. In one dimension the nature of correlations in the antiferromagnetic Heisenberg model depends on the spin of the magnetic dipoles. If the spin is integer then only short-range order is present. A system of half-integer spins exhibits quasi-long range order.
A simplified version of Heisenberg model is the one-dimensional Ising model, where the transverse magnetic field is in the x-direction, and the interaction is only in the z-direction:
At small g and large g, the ground state degeneracy is different, which implies that there must be a quantum phase transition in between. It can be solved exactly for the critical point using the duality analysis. The duality transition of the Pauli matrices is and , where and are also Pauli matrices which obey the Pauli matrix algebra.
Under periodic boundary conditions, the transformed Hamiltonian can be shown is of a very similar form:
but for the attached to the spin interaction term. Assuming that there's only one critical point, we can conclude that the phase transition happens at . | 3 | Magnetic Ordering |
The glucosinolate sinigrin, among others, was shown to be responsible for the bitterness of cooked cauliflower and Brussels sprouts. Glucosinolates may alter animal eating behavior. | 2 | Carbohydrates |