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* Potassium lactobionate: 100 mM
* KHPO: 25 mM
* MgSO: 5 mM
* Raffinose: 30 mM
* Adenosine: 5 mM
* Glutathione: 3 mM
* Allopurinol: 1 mM
* Hydroxyethyl starch: 50 g/L | 0 | Cryobiology |
Germicidal lamps are used to sterilize workspaces and tools used in biology laboratories and medical facilities. If the quartz envelope transmits shorter wavelengths, such as the 185 nm mercury emission line, they can also be used wherever ozone is desired, for example, in the sanitizing systems of hot tubs and aquariums. They are also used by geologists to provoke fluorescence in mineral samples, aiding in their identification. In this application, the light produced by the lamp is usually filtered to remove as much visible light as possible, leaving just the UV light. Germicidal lamps are also used in waste water treatment in order to kill microorganisms.
The light produced by germicidal lamps is also used to erase EPROMs; the ultraviolet photons are sufficiently energetic to allow the electrons trapped on the transistors' floating gates to tunnel through the gate insulation, eventually removing the stored charge that represents binary ones and zeroes. | 4 | Ultraviolet Radiation |
Embryos can be either "fresh" from fertilized egg cells of the same menstrual cycle, or "frozen", that is they have been generated in a preceding cycle and undergone embryo cryopreservation, and are thawed just prior to the transfer, which is then termed "frozen embryo transfer" (FET). The outcome from using cryopreserved embryos has uniformly been positive with no increase in birth defects or development abnormalities, also between fresh versus frozen eggs used for intracytoplasmic sperm injection (ICSI). In fact, pregnancy rates are increased following FET, and perinatal outcomes are less affected, compared to embryo transfer in the same cycle as ovarian hyperstimulation was performed. The endometrium is believed to not be optimally prepared for implantation following ovarian hyperstimulation, and therefore frozen embryo transfer avails for a separate cycle to focus on optimizing the chances of successful implantation. Children born from vitrified blastocysts have significantly higher birthweight than those born from non-frozen blastocysts. When transferring a frozen-thawed oocyte, the chance of pregnancy is essentially the same whether it is transferred in a natural cycle or one with ovulation induction.
There is probably little or no difference between FET and fresh embryo transfers in terms of live birth rate and ongoing pregnancy rate and the risk of ovarian hyperstimulation syndrome may be less using the "freeze all" strategy. The risk of having a large-for-gestational-age baby and higher birth rate, in addition to maternal hypertensive disorders of pregnancy may be increased using a "freeze all" strategy. | 0 | Cryobiology |
Weerman degradation, also named Weerman reaction, is a name reaction in organic chemistry. It is named after Rudolf Adrian Weerman, who discovered it in 1910. In general, it is an organic reaction in carbohydrate chemistry in which amides are degraded by sodium hypochlorite, forming an aldehyde with one less carbon. Some have regarded it as an extension of the Hofmann rearrangement. | 2 | Carbohydrates |
Magnetic phase transitions can be either first order or second order. The nature of the transition can be inferred from the Arrott plot based on the slope of the magnetic isotherms. If the lines are all positive slope, the phase transition is second order, whereas if there are negative slope lines, the phase transition is first order. This condition is known as the Banerjee criterion.
The Banerjee criterion is not always accurate for evaluating inhomogeneous ferromagnets, since the slopes can all be positive even when the transition is first-order. | 3 | Magnetic Ordering |
A Rotary Vacuum Filter Drum consists of a cylindrical filter membrane that is partly sub-merged in a slurry to be filtered. The inside of the drum is held lower than the ambient pressure. As the drum rotates through the slurry, the liquid is sucked through the membrane, leaving solids to cake on the membrane surface while the drum is submerged. A knife or blade is positioned to scrape the product from the surface.
The technique is well suited to slurries, flocculated suspensions, and liquids with a high solid content, which could clog other forms of filter. It is common to pre-coated with a filter aid, typically of diatomaceous earth (DE) or Perlite. In some implementations, the knife also cuts off a small portion of the filter media to reveal a fresh media surface that will enter the liquid as the drum rotates. Such systems advance the knife automatically as the surface is removed. | 1 | Separation Processes |
Genetic disorders are often an issue within captive populations due to the fact that the populations are usually established from a small number of founders. In large, outbreeding populations, the frequencies of most deleterious alleles are relatively low, but when a population undergoes a bottleneck during the founding of a captive population, previously rare alleles may survive and increase in number. Further inbreeding within the captive population may also increase the likelihood that deleterious alleles will be expressed due to increasing homozygosity within the population. The high occurrence of genetic disorders within a captive population can threaten both the survival of the captive population and its eventual reintroduction back into the wild. If the genetic disorder is dominant, it may be possible to eliminate the disease completely in a single generation by avoiding breeding of the affected individuals. However, if the genetic disorder is recessive, it may not be possible to completely eliminate the allele due to its presence in unaffected heterozygotes. In this case, the best option is to attempt to minimize the frequency of the allele by selectively choosing mating pairs. In the process of eliminating genetic disorders, it is important to consider that when certain individuals are prevented from breeding, alleles and therefore genetic diversity are removed from the population; if these alleles are not present in other individuals, they may be lost completely. Preventing certain individuals from the breeding also reduces the effective population size, which is associated with problems such as the loss of genetic diversity and increased inbreeding. | 0 | Cryobiology |
Laboratories have developed grading methods to judge ovocyte and embryo quality. In order to optimise pregnancy rates, there is significant evidence that a morphological scoring system is the best strategy for the selection of embryos. Since 2009 where the first time-lapse microscopy system for IVF was approved for clinical use, morphokinetic scoring systems has shown to improve to pregnancy rates further. However, when all different types of time-lapse embryo imaging devices, with or without morphokinetic scoring systems, are compared against conventional embryo assessment for IVF, there is insufficient evidence of a difference in live-birth, pregnancy, stillbirth or miscarriage to choose between them. Active efforts to develop a more accurate embryo selection analysis based on Artificial Intelligence and Deep Learning are underway. Embryo Ranking Intelligent Classification Assistant (ERICA), is a clear example. This Deep Learning software substitutes manual classifications with a ranking system based on an individual embryo's predicted genetic status in a non-invasive fashion. Studies on this area are still pending and current feasibility studies support its potential. | 0 | Cryobiology |
An increasingly popular method of cleaning windows is the "water-fed pole" system. Instead of washing windows with conventional detergent, they are scrubbed with purified water, typically containing less than 10 ppm dissolved solids, using a brush on the end of a pole wielded from ground level. RO is commonly used to purify the water. | 1 | Separation Processes |
The significance of sources of FODMAPs varies through differences in dietary groups such as geography, ethnicity, and other factors. Commonly used FODMAPs comprise the following:
* oligosaccharides, including fructans and galactooligosaccharides
* disaccharides, including lactose
* monosaccharides, including fructose
* polyols, including sorbitol, xylitol, and mannitol | 2 | Carbohydrates |
A gaur that died of natural causes had some skin cells frozen and added to the San Diego Frozen Zoo. Eight years later, DNA from these cells was inserted into a domestic-cow egg to create an embryo (trans-species cloning), which was then implanted in a domestic cow (Bos taurus). On 8 January 2001, the gaur, named Noah, was born in Sioux Center, Iowa. Noah was initially healthy, but the next day, he came down with clostridial enteritis, and died of dysentery within 48 hours of birth. This is not uncommon in uncloned animals, and the researchers did not think it was due to the cloning. | 0 | Cryobiology |
Superparamagnetism is a form of magnetism which appears in small ferromagnetic or ferrimagnetic nanoparticles. In sufficiently small nanoparticles, magnetization can randomly flip direction under the influence of temperature. The typical time between two flips is called the Néel relaxation time. In the absence of an external magnetic field, when the time used to measure the magnetization of the nanoparticles is much longer than the Néel relaxation time, their magnetization appears to be in average zero; they are said to be in the superparamagnetic state. In this state, an external magnetic field is able to magnetize the nanoparticles, similarly to a paramagnet. However, their magnetic susceptibility is much larger than that of paramagnets. | 3 | Magnetic Ordering |
Freezing is almost always an exothermic process, meaning that as liquid changes into solid, heat and pressure are released. This is often seen as counter-intuitive, since the temperature of the material does not rise during freezing, except if the liquid were supercooled. But this can be understood since heat must be continually removed from the freezing liquid or the freezing process will stop. The energy released upon freezing is a latent heat, and is known as the enthalpy of fusion and is exactly the same as the energy required to melt the same amount of the solid.
Low-temperature helium is the only known exception to the general rule. Helium-3 has a negative enthalpy of fusion at temperatures below 0.3 K. Helium-4 also has a very slightly negative enthalpy of fusion below 0.8 K. This means that, at appropriate constant pressures, heat must be added to these substances in order to freeze them. | 0 | Cryobiology |
The eggs are retrieved from the patient using a transvaginal technique called transvaginal oocyte retrieval, involving an ultrasound-guided needle piercing the vaginal wall to reach the ovaries. Through this needle follicles can be aspirated, and the follicular fluid is passed to an embryologist to identify ova. It is common to remove between ten and thirty eggs. The retrieval process, which lasts approximately 20 to 40 minutes, is performed under conscious sedation or general anesthesia to ensure patient comfort. Following optimal follicular development, the eggs are meticulously retrieved using transvaginal ultrasound guidance with the aid of a specialised ultrasound probe and a fine needle aspiration technique. The follicular fluid, containing the retrieved eggs, is expeditiously transferred to the embryology laboratory for subsequent processing. | 0 | Cryobiology |
Heavy liquids such as tetrabromoethane can be used to separate ores from supporting rocks by preferential flotation. The rocks are crushed, and while sand, limestone, dolomite, and other types of rock material will float on TBE, ores such as sphalerite, galena and pyrite will sink. | 1 | Separation Processes |
Cryosurgery is a minimally invasive procedure, and is often preferred to other types of surgery because of its safety, ease of use, minimal pain and scarring as well as low cost; however, as with any medical treatment, there are risks involved, primarily that of damage to nearby healthy tissue. Damage to nerve tissue is of particular concern but is rare.
Cryosurgery cannot be used on lesions that would subsequently require biopsy as the technique destroys tissue and precludes the use of histopathology.
More common complications of cryosurgery include blistering and edema which are transient. Cryosurgery may cause complications due to damage of underlying structures. Destruction of the basement membrane may cause scarring and destruction of hair follicles can cause alopecia or hair loss. Occasionally, hypopigmentation may occur in the area of skin treated with cryosurgery, however, this complication is usually transient and often resolves as melanocytes migrate and repigment the area over several months. Bleeding can also occur, which can be delayed or immediate, due to damage of underlying arteries and arterioles. Tendon rupture and cartillage necrosis can occur, particularly if cryosurgery is done over bony prominences. These complications can be avoided or minimized if freeze times of less than 30 seconds are used during cryosurgery.
Patients undergoing cryosurgery usually experience redness and minor-to-moderate localized pain, which most of the time can be alleviated sufficiently by oral administration of mild analgesics such as ibuprofen, codeine or acetaminophen (paracetamol). Blisters may form as a result of cryosurgery, but these usually scab over and peel away within a few days. | 0 | Cryobiology |
During the degradation of α-hydroxy-substituted carbonic acid amides, the carbon chain shortens by one carbon-atom.
The reaction proceeds very slowly at room temperature, therefore the reaction mixture is heated up to 60-65 °C. | 2 | Carbohydrates |
Consider a quantum mechanical system with Hilbert space spanned by , where is the total angular momentum and is its projection on the quantization axis. Then any quantum operators can be represented using the basis set as a matrix with dimension . Therefore, one can define matrices to completely expand any quantum operator in this Hilbert space. Taking J=1/2 as an example, a quantum operator A can be expanded as
Obviously, the matrices: form a basis set in the operator space. Any quantum operator defined in this Hilbert can be expended by operators. In the following, let's call these matrices as a super basis to distinguish the eigen basis of quantum states. More specifically the above super basis can be called a transition super basis because it describes the transition between states and . In fact, this is not the only super basis that does the trick. We can also use Pauli matrices and the identity matrix to form a super basis
Since the rotation properties of follow the same rules as the rank 1 tensor of cubic harmonics and the identity matrix follows the same rules as the rank 0 tensor , the basis set can be called cubic super basis. Another commonly used super basis is spherical harmonic super basis which is built by replacing the to the raising and lowering operators
Again, share the same rotational properties as rank 1 spherical harmonic tensors , so it is called spherical super basis.
Because atomic orbitals are also described by spherical or cubic harmonic functions, one can imagine or visualize these operators using the wave functions of atomic orbitals although they are essentially matrices not spatial functions.
If we extend the problem to , we will need 9 matrices to form a super basis. For transition super basis, we have . For cubic super basis, we have . For spherical super basis, we have . In group theory, are called scalar or rank 0 tensor, are called dipole or rank 1 tensors, are called quadrupole or rank 2 tensors.
The example tells us, for a -multiplet problem, one will need all rank tensor operators to form a complete super basis. Therefore, for a system, its density matrix must have quadrupole components. This is the reason why a problem will automatically introduce high-rank multipoles to the system | 3 | Magnetic Ordering |
Initial salting in at low concentrations is explained by the Debye–Huckel theory. Proteins are surrounded by the salt counterions (ions of opposite net charge) and this screening results in decreasing electrostatic free energy of the protein and increasing activity of the solvent, which in turn leads to increasing solubility. This theory predicts that the logarithm of solubility is proportional to the square root of the ionic strength.
The behavior of proteins in solutions at high salt concentrations is explained by John Gamble Kirkwood. The abundance of the salt ions decreases the solvating power of salt ions, resulting in the decrease in the solubility of the proteins and precipitation results.
At high salt concentrations, the solubility is given by the following empirical expression.
:log S = B − KI
where S is the solubility of the protein, B is a constant (function of protein, pH and temperature), K is the salting out constant (function of pH, mixing and salt), and I is the ionic strength of the salt. This expression is an approximation to that proposed by Long and McDevit. | 1 | Separation Processes |
In solid state physics, the magnetic space groups, or Shubnikov groups, are the symmetry groups which classify the symmetries of a crystal both in space, and in a two-valued property such as electron spin. To represent such a property, each lattice point is colored black or white, and in addition to the usual three-dimensional symmetry operations, there is a so-called "antisymmetry" operation which turns all black lattice points white and all white lattice points black. Thus, the magnetic space groups serve as an extension to the crystallographic space groups which describe spatial symmetry alone.
The application of magnetic space groups to crystal structures is motivated by Curies Principle. Compatibility with a materials symmetries, as described by the magnetic space group, is a necessary condition for a variety of material properties, including ferromagnetism, ferroelectricity, topological insulation. | 3 | Magnetic Ordering |
The primary structure of RiAFP (the sequence may be found [https://www.ncbi.nlm.nih.gov/protein/313766639 here]) determined by Mass Spectroscopy, Edman degradation and by constructing a partial cDNA sequence and PCR have shown that a TxTxTxT internal repeat exists. Sequence logos constructed from the RiAFP internal repeats, have been particularly helpful in the determination of the consensus sequence of these repeats. The TxTxTxT domains are irregularly spaced within the protein and have been shown to be conserved from the TxT binding motif of other AFPs. The hydroxyl moiety of the T residues fits well, when spaced as they are in the internal repeats, with the hydroxyl moieties of externally facing water molecules in the forming ice lattice. This mimics the formation of the growth cone at a nucleation site in the absence of AFPs. Thus, the binding of RiAFP inhibits the growth of the crystal in the basal and prism planes of the ice. | 0 | Cryobiology |
Children and adolescents who use tanning beds are at greater risk because of biological vulnerability to UV radiation. Epidemiological studies have shown that exposure to artificial tanning increases the risk of malignant melanoma and that the longer the exposure, the greater the risk, particularly in individuals exposed before the age of 30 or who have been sunburned.
One study conducted among college students found that awareness of the risks of tanning beds did not deter the students from using them. Teenagers are frequent targets of tanning industry marketing, which includes offers of coupons and placing ads in high-school newspapers. Members of the United States House Committee on Energy and Commerce commissioned a "sting" operation in 2012, in which callers posing as a 16-year-old woman who wanted to tan for the first time called 300 tanning salons in the US. Staff reportedly failed to follow FDA recommendations, denied the risks of tanning, and offered misleading information about benefits. | 4 | Ultraviolet Radiation |
Chemoenzymatic labeling provides an alternative strategy to incorporate handles for click chemistry. The Click-IT O-GlcNAc Enzymatic Labeling System, developed by the Hsieh-Wilson group and subsequently commercialized by Invitrogen, utilizes a mutant GalT Y289L enzyme that is able to transfer azidogalactose (GalNAz) onto O-GlcNAc. The presence of GalNAz (and therefore also O-GlcNAc) can be detected with various alkyne-containing probes with identifiable tags such as biotin, dye molecules, and PEG. | 2 | Carbohydrates |
From manna, produced by several species of tree and shrub e.g. Fraxinus ornus from whose secretions mannitol was originally isolated. | 2 | Carbohydrates |
In a conventional n-type DSSC, sunlight enters the cell through the transparent SnO:F top contact, striking the dye on the surface of the TiO. Photons striking the dye with enough energy to be absorbed create an excited state of the dye, from which an electron can be "injected" directly into the conduction band of the TiO. From there it moves by diffusion (as a result of an electron concentration gradient) to the clear anode on top.
Meanwhile, the dye molecule has lost an electron and the molecule will decompose if another electron is not provided. The dye strips one from iodide in electrolyte below the TiO, oxidizing it into triiodide. This reaction occurs quite quickly compared to the time that it takes for the injected electron to recombine with the oxidized dye molecule, preventing this recombination reaction that would effectively short-circuit the solar cell.
The triiodide then recovers its missing electron by mechanically diffusing to the bottom of the cell, where the counter electrode re-introduces the electrons after flowing through the external circuit. | 4 | Ultraviolet Radiation |
Electronic components that require clear transparency for light to exit or enter (photovoltaic panels and sensors) can be potted using acrylic resins that are cured using UV energy. The advantages are low VOC emissions and rapid curing.
Certain inks, coatings, and adhesives are formulated with photoinitiators and resins. When exposed to UV light, polymerization occurs, and so the adhesives harden or cure, usually within a few seconds. Applications include glass and plastic bonding, optical fiber coatings, the coating of flooring, UV coating and paper finishes in offset printing, dental fillings, and decorative fingernail "gels".
UV sources for UV curing applications include UV lamps, UV LEDs, and excimer flash lamps. Fast processes such as flexo or offset printing require high-intensity light focused via reflectors onto a moving substrate and medium so high-pressure Hg (mercury) or Fe (iron, doped)-based bulbs are used, energized with electric arcs or microwaves. Lower-power fluorescent lamps and LEDs can be used for static applications. Small high-pressure lamps can have light focused and transmitted to the work area via liquid-filled or fiber-optic light guides.
The impact of UV on polymers is used for modification of the (roughness and hydrophobicity) of polymer surfaces. For example, a poly(methyl methacrylate) surface can be smoothed by vacuum ultraviolet.
UV radiation is useful in preparing low-surface-energy polymers for adhesives. Polymers exposed to UV will oxidize, thus raising the surface energy of the polymer. Once the surface energy of the polymer has been raised, the bond between the adhesive and the polymer is stronger. | 4 | Ultraviolet Radiation |
For higher grade applications such as ferrous metals, coal and industrial minerals, sensor-based ore sorting can be applied to create a final product. Pre-condition is, that the liberation allows for the creation of a sellable product. Undersize material is usually bypassed as product, but can also be diverted to the waste fraction, if the composition does not meet the required specifications. This is case and application dependent. | 1 | Separation Processes |
Amylopectin has seen a rise of use in biomedical applications due to its physiological factors, ease of availability, and low cost. Specifically, amylopectin has very advantageous biochemical properties due to its prevalence as a natural polysaccharide. This causes a high sense of biocompatibility with cells and molecules within the body. Amylopectin is also able to biodegrade to a high degree due to its high sense of crosslinking with 1,6 glycosidic bonds. These bonds are easily broken down by the body can reduce molecular weight, expose certain regions, and interact certain bonds with clinical factors. Various physical, chemical, and enzymatic methods of modification have also been researched for amylopectin. These, generally, allow for enhanced and controllable properties which can be selected for the field of research performed. Amylopectin's main role, clinically, is within its integration in starch. Function and structure of amylopectin is based on its integration with amylose and other bounded molecules. Separating these molecules and isolated amylopectin is quite difficult for researchers to perform. | 2 | Carbohydrates |
A solar-powered desalination unit produces potable water from saline water by using a photovoltaic system to supply the energy. Solar power works well for water purification in settings lacking grid electricity and can reduce operating costs and greenhouse emissions. For example, a solar-powered desalination unit designed passed tests in Australia's Northern Territory.
Sunlight's intermittent nature makes output prediction difficult without an energy storage capability. However batteries or thermal energy storage systems can provide power when the sun does not. | 1 | Separation Processes |
Genetic diversity is often lost within captive populations due to the founder effect and subsequent small population sizes. Minimizing the loss of genetic diversity within the captive population is an important component of ex situ conservation and is critical for successful reintroductions and the long term success of the species, since more diverse populations have higher adaptive potential. The loss of genetic diversity due to the founder effect can be minimized by ensuring that the founder population is large enough and genetically representative of the wild population. This is often difficult because removing large numbers of individuals from the wild populations may further reduce the genetic diversity of a species that is already of conservation concern. An alternative to this is collecting sperm from wild individuals and using this via artificial insemination to bring in fresh genetic material. Maximizing the captive population size and the effective population size can decrease the loss of genetic diversity by minimizing the random loss of alleles due to genetic drift. Minimizing the number of generations in captivity is another effective method for reducing the loss of genetic diversity in captive populations. | 0 | Cryobiology |
In altermagnetic materials, atoms form a regular pattern with alternating spin and spatial orientation at adjacent magnetic sites in the crystal.
Atoms with opposite magnetic moment are in altermagnets coupled by crystal rotation or mirror symmetry. The spatial orientation of magnetic atoms may originate from the surrounding cages of non-magnetic atoms. The opposite spin sublattices in altermagnetic manganese telluride (MnTe) are related by spin rotation combined with six-fold crystal rotation and half-unit cell translation. In altermagnetic ruthenium dioxide (RuO), the opposite spin sublattices are related by four-fold crystal rotation. | 3 | Magnetic Ordering |
Glucosinolates and their products have a negative effect on many insects, resulting from a combination of deterrence and toxicity. In an attempt to apply this principle in an agronomic context, some glucosinolate-derived products can serve as antifeedants, i.e., natural pesticides.
In contrast, the diamondback moth, a pest of cruciferous plants, may recognize the presence of glucosinolates, allowing it to identify the proper host plant. Indeed, a characteristic, specialised insect fauna is found on glucosinolate-containing plants, including butterflies, such as large white, small white, and orange tip, but also certain aphids, moths, such as the southern armyworm, sawflies, and flea beetles. For instance, the large white butterfly deposits its eggs on these glucosinolate-containing plants, and the larvae survive even with high levels of glucosinolates and eat plant material containing glucosinolates. The whites and orange tips all possess the so-called nitrile specifier protein, which diverts glucosinolate hydrolysis toward nitriles rather than reactive isothiocyanates. In contrast, the diamondback moth possesses a completely different protein, glucosinolate sulfatase, which desulfates glucosinolates, thereby making them unfit for degradation to toxic products by myrosinase.
Other kinds of insects (specialised sawflies and aphids) sequester glucosinolates. In specialised aphids, but not in sawflies, a distinct animal myrosinase is found in muscle tissue, leading to degradation of sequestered glucosinolates upon aphid tissue destruction. This diverse panel of biochemical solutions to the same plant chemical plays a key role in the evolution of plant-insect relationships. | 2 | Carbohydrates |
In physics, the Landau–Lifshitz–Gilbert equation (usually abbreviated as LLG equation), named for Lev Landau, Evgeny Lifshitz, and T. L. Gilbert, is a name used for a differential equation describing the dynamics (typically the precessional motion) of magnetization in a solid. It is a modified version by Gilbert of the original equation of Landau and Lifshitz. The LLG equation is similar to the Bloch equation, but they differ in the form of the damping term. The LLG equation describes a more general scenario of magnetization dynamics beyond the simple Larmor precession. In particular, the effective field driving the precessional motion of is not restricted to real magnetic fields; it incorporates a wide range of mechanisms including magnetic anisotropy, exchange interaction, and so on.
The various forms of the LLG equation are commonly used in micromagnetics to model the effects of a magnetic field and other magnetic interactions on ferromagnetic materials. It provides a practical way to model the time-domain behavior of magnetic elements. Recent developments generalizes the LLG equation to include the influence of spin-polarized currents in the form of spin-transfer torque. | 3 | Magnetic Ordering |
There are currently very few ova banks in existence.
Generally, the main purpose of storing ova, at present, is to overcome infertility which may arise at a later age, or due to a disease. The ova are generally collected between 31 and 35 years of age.
The procedure of collecting ova may or may not include ovarian hyperstimulation.
It can be expected however that ova collection will become more important in the future, i.e. for third party reproduction, and/or for producing stem cells, i.e. from unfertilized eggs (oocytes). | 0 | Cryobiology |
In 1832, H.A.L. Wiggers discovered trehalose in an ergot of rye, and in 1859 Marcellin Berthelot isolated it from Trehala manna, a substance made by weevils and named it trehalose.
Trehalose has long been known as an autophagy inducer that acts independently of mTOR. In 2017, research was published showing that trehalose induces autophagy by activating TFEB, a protein that acts as a master regulator of the autophagy-lysosome pathway. | 2 | Carbohydrates |
DEHPA is prepared through the reaction of phosphorus pentoxide and 2-ethylhexanol:
:4 CHOH + PO → 2 [(CHO)PO(OH)]O
:[(CHO)PO(OH)]O + CHOH → (CHO)PO(OH) + (CHO)PO(OH)
These reaction produce a mixture of mono-, di-, and trisubstituted phosphates, from which DEHPA can be isolated based on solubility. | 1 | Separation Processes |
Application of this discharge are usually seen where production of filter cakes that blind the filter media thoroughly and processes that have low solid concentration slurry. Pre coat discharge is used if slurry with very low solid concentration slurry is used that resulted in difficult cake formation or if the slurry is difficult to filter to produce cake . | 1 | Separation Processes |
Staying dry and wearing proper clothing help to prevent hypothermia. Synthetic and wool fabrics are superior to cotton as they provide better insulation when wet and dry. Some synthetic fabrics, such as polypropylene and polyester, are used in clothing designed to wick perspiration away from the body, such as liner socks and moisture-wicking undergarments. Clothing should be loose fitting, as tight clothing reduces the circulation of warm blood. In planning outdoor activity, prepare appropriately for possible cold weather. Those who drink alcohol before or during outdoor activity should ensure at least one sober person is present responsible for safety.
Covering the head is effective, but no more effective than covering any other part of the body. While common folklore says that people lose most of their heat through their heads, heat loss from the head is no more significant than that from other uncovered parts of the body. However, heat loss from the head is significant in infants, whose head is larger relative to the rest of the body than in adults. Several studies have shown that for uncovered infants, lined hats significantly reduce heat loss and thermal stress. Children have a larger surface area per unit mass, and other things being equal should have one more layer of clothing than adults in similar conditions, and the time they spend in cold environments should be limited. However children are often more active than adults, and may generate more heat. In both adults and children, overexertion causes sweating and thus increases heat loss.
Building a shelter can aid survival where there is danger of death from exposure. Shelters can be constructed out of a variety of materials. Metal can conduct heat away from the occupants and is sometimes best avoided. The shelter should not be too big so body warmth stays near the occupants. Good ventilation is essential especially if a fire will be lit in the shelter. Fires should be put out before the occupants sleep to prevent carbon monoxide poisoning. People caught in very cold, snowy conditions can build an igloo or snow cave to shelter.
The United States Coast Guard promotes using life vests to protect against hypothermia through the 50/50/50 rule: If someone is in water for 50 minutes, they have a 50 percent better chance of survival if they are wearing a life jacket. A heat escape lessening position can be used to increase survival in cold water.
Babies should sleep at 16–20 °C (61–68 °F) and housebound people should be checked regularly to make sure the temperature of the home is at least 18 °C (64 °F). | 0 | Cryobiology |
It is convenient to generate excimer molecules in a plasma. Electrons play an important role in a plasma and, in particular, in the formation of excimer molecules. To efficiently generate excimer molecules, the working medium (plasma) should contain sufficient concentration of electrons with energies that are high enough to produce the precursors of the excimer molecules, which are mainly excited and ionized rare gas atoms. Introduction of power into a gaseous mixture results in the formation of excited and ionized rare gas atoms as follows:
Electron excitation
:Rg + e → Rg* + e,
Direct electron ionization
:Rg + e → Rg + 2e,
Stepwise ionization
:Rg* + e → Rg + 2e,
where Rg* is a rare gas atom in an excited electronic state, Rg is a rare gas ion, and e is an electron.
When there are enough excited rare gas atoms accumulated in a plasma, the excimer molecules are formed by the following reaction:
:Rg* + Rg + M → Rg* + M,
where Rg* is an excimer molecule, and M is a third particle carrying away the excess energy to stabilize an excimer molecule. As a rule, it is a rare gas atom of the working medium.
Analyzing this three-body reaction, one can see that the efficiency of the production of excimer molecules is proportional to the concentration of excited rare gas atoms and the square of the concentration of rare gas atoms in the ground state. From this point of view, the concentration of rare gas in the working medium should be as high as possible. A higher concentration of rare gas is achieved by increasing gas pressure. However, an increase in the concentration of rare gas also intensifies the collisional quenching of excimer molecules, resulting in their radiationless decay:
:Rg* + Rg → Rg* + 2Rg.
The collisional quenching of excimer molecules is negligible while the mean time between collisions is much higher than the lifetime of an excimer molecule in an excited electronic state. In practice, the optimal pressure of a working medium is found experimentally, and it amounts to approximately one atmosphere.
A mechanism underlying the formation of exciplex molecules (rare gas halides) is a bit more complicated than the mechanism of excimer molecule formation. The formation of exciplex molecules occurs in two main ways. The first way is due to a reaction of ion-ion recombination, i.e., recombination of a positive rare gas ion and a negative halogen ion:
:Rg + X + M → RgX* + M,
where RgX* is an exciplex molecule, and M is a collisional third partner, which is usually an atom or molecule of a gaseous mixture or buffer gas. The third particle takes the excess energy and stabilizes an exciplex molecule.
The formation of a negative halogen ion results from the interaction of a low-energy electron with a halogen molecule in a so-called process of the dissociative electron attachment:
:X + e → X + X,
where X is a halogen atom.
The pressure of a gaseous mixture is of great importance for efficient production of exciplex molecules due to the reaction of ion-ion recombination. The process of ion-ion recombination is dependent on three-body collisions, and the probability of such a collision increases with pressure. At low pressures of a gaseous mixture (several tens of torr), the reaction of ion-ion recombination is of little efficiency, while it is quite productive at pressures above 100 Torr.
The second way of the formation of exciplex molecules is a harpoon reaction. In this case, a halogen molecule or halogen-containing compound captures a weakly bound electron of an excited rare gas atom, and an exciplex molecule in an excited electronic state is formed:
:Rg* + X → RgX* + X.
Since the harpoon reaction is a process of a two-body collision, it can proceed productively at a pressure significantly lower than that required for a three-body reaction. Thus, the harpoon reaction makes possible the efficient operation of an excimer lamp at low pressures of a gaseous mixture. The collisional quenching of exciplex molecules at low pressures of a gaseous mixture is much lower than at pressures required for productive proceeding the reaction of ion-ion recombination. Due to this, a low-pressure excimer lamp ensures the maximum efficiency in converting the pumping energy to UV radiation.
It should be mentioned that both the harpoon reaction and reaction of ion-ion recombination proceed simultaneously. The dominance of the first or second reaction is mainly determined by the pressure of a gaseous mixture. The harpoon reaction predominates at low pressures (below 50 Torr), while the reaction of ion-ion recombination prevails at higher pressures (above 100 Torr).
The kinetics of reactions proceeding in a plasma is diverse and is not limited to the processes considered above. The efficiency of producing exciplex molecules depends on the composition of a gaseous mixture and conditions of its excitation. The type of halogen donor plays an important role. The most effective and widely used halogen-carriers are homonuclear diatomic halogen molecules. More complex halogen compounds such as hydrogen halides, metal halides, and interhalogens are also used as a halogen-carrier but to a lesser extent.
A noteworthy halogen-carrier is alkali halide. A feature of alkali halides is a similarity of their chemical bond with that of exciplex molecules in excited electronic states. Exciplex molecules in excited electronic states are characterized by the ionic bond as well as alkali halides in the ground state. It opens up alternative mechanisms for the formation of exciplex molecules, namely substitution reactions:
:Rg* + AX → RgX* + A,
:Rg + AX → RgX* + A,
where AX is an alkali halide molecule, A is an alkali metal atom, and A is an alkali metal ion.
These mechanisms of the formation of exciplex molecules are fundamentally different from the reaction of ion-ion recombination and harpoon reaction. An exciplex molecule is formed simply by replacing an atom/ion of alkali metal from an alkali halide molecule by an excited atom/ion of rare gas.
An advantage of using alkali halides is that both the substitution reactions can simultaneously proceed at low pressures with comparable productivity. Moreover, both excited atoms and ions of rare gas are effectively used in the production of exciplex molecules in contrast to excimer lamps using other halogen-carriers. It is of importance because the ionization and excitation of rare gas consume most of the introduced energy. Since the reaction of ion-ion recombination and harpoon reaction dominate depending on the pressure of a gaseous mixture, the generation of rare gas ions is unprofitable at low pressures, while the excitation of rare gas is unreasonable at high pressures. A drawback of using alkali halides is high temperatures required for providing the necessary concentration of alkali halide molecules in a gaseous mixture. Despite this, the use of alkali halides as a halogen-carrier is especially promising in the development of exciplex lasers operating at low pressures. | 4 | Ultraviolet Radiation |
The live birth rate is the percentage of all IVF cycles that lead to a live birth. This rate does not include miscarriage or stillbirth; multiple-order births, such as twins and triplets, are counted as one pregnancy. A 2019 summary compiled by the Society for Assisted Reproductive Technology (SART) which reports the average IVF success rates in the United States per age group using non-donor eggs compiled the following data:
In 2006, Canadian clinics reported a live birth rate of 27%. Birth rates in younger patients were slightly higher, with a success rate of 35.3% for those 21 and younger, the youngest group evaluated. Success rates for older patients were also lower and decrease with age, with 37-year-olds at 27.4% and no live births for those older than 48, the oldest group evaluated. Some clinics exceeded these rates, but it is impossible to determine if that is due to superior technique or patient selection, since it is possible to artificially increase success rates by refusing to accept the most difficult patients or by steering them into oocyte donation cycles (which are compiled separately). Further, pregnancy rates can be increased by the placement of several embryos at the risk of increasing the chance for multiples.
Because not each IVF cycle that is started will lead to oocyte retrieval or embryo transfer, reports of live birth rates need to specify the denominator, namely IVF cycles started, IVF retrievals, or embryo transfers. The SART summarised 2008–9 success rates for US clinics for fresh embryo cycles that did not involve donor eggs and gave live birth rates by the age of the prospective mother, with a peak at 41.3% per cycle started and 47.3% per embryo transfer for patients under 35 years of age.
IVF attempts in multiple cycles result in increased cumulative live birth rates. Depending on the demographic group, one study reported 45% to 53% for three attempts, and 51% to 71% to 80% for six attempts.
Effective from 15 February 2021 the majority of Australian IVF clinics publish their individual success rate online via YourIVFSuccess.com.au. This site also contains a predictor tool. | 0 | Cryobiology |
O-GlcNAc is generally a dynamic modification that can be cycled on and off various proteins. Some residues are thought to be constitutively modified by O-GlcNAc. The O-GlcNAc modification is installed by OGT in a sequential bi-bi mechanism where the donor sugar, UDP-GlcNAc, binds to OGT first followed by the substrate protein. The O-GlcNAc modification is removed by OGA in a hydrolysis mechanism involving anchimeric assistance (substrate-assisted catalysis) to yield the unmodified protein and GlcNAc. While crystal structures have been reported for both OGT and OGA, the exact mechanisms by which OGT and OGA recognize substrates have not been completely elucidated. Unlike N-linked glycosylation, for which glycosylation occurs in a specific consensus sequence (Asn-X-Ser/Thr, where X is any amino acid except Pro), no definitive consensus sequence has been identified for O-GlcNAc,. Consequently, predicting sites of O-GlcNAc modification is challenging, and identifying modification sites generally requires mass spectrometry methods. For OGT, studies have shown that substrate recognition is regulated by a number of factors including aspartate and asparagine ladder motifs in the lumen of the superhelical TPR domain, active site residues, and adaptor proteins. As crystal structures have shown that OGT requires its substrate to be in an extended conformation, it has been proposed that OGT has a preference for flexible substrates. In in vitro kinetic experiments measuring OGT and OGA activity on a panel of protein substrates, kinetic parameters for OGT were shown to be variable between various proteins while kinetic parameters for OGA were relatively constant between various proteins. This result suggested that OGT is the "senior partner" in regulating O-GlcNAc and OGA primarily recognizes substrates via the presence of O-GlcNAc rather than the identity of the modified protein. | 2 | Carbohydrates |
In 1946, some maple syrup producers started using RO to remove water from sap before boiling the sap to syrup. RO allows about 75–90% of the water to be removed, reducing energy consumption and exposure of the syrup to high temperatures. | 1 | Separation Processes |
Immunological effects resulting from the cryoablation of tumors was first observed in the 1960s. Since the 1960s, Tanaka treated metastatic breast cancer patients with cryotherapy and reported cryoimmunological reaction resulting from cryotherapy. In the 1970s, systemic immunological response from local cryoablation of prostate cancer was also clinically observed. In the 1980s, Tanaka, of Japan, continued to advance the clinical practice of cryoimmunology with combination treatments including: cryochemotherapy and cryoimmunotherapy. In 1997, Russian scientists confirmed the efficacy of cryoimmunotherapy in inhibiting metastases in advanced cancer. In 2000s, China, following closely with the exciting developments, enthusiastically embraced cryoablation treatment for cancer and has been leading the practice ever since with cryoimmunotherapy treatments available for cancer patients in numerous hospitals and medical clinics throughout China. In the 2010s, American researchers and medical professionals, started to explore cryoimmunotherapy for systemic treatment of cancer. | 0 | Cryobiology |
Ultraviolet-sensitive beads (UV beads) are beads that are colorful in the presence of ultraviolet radiation. Ultraviolet rays are present in sunlight and light from various artificial sources and can cause sunburn or skin cancer. The color change in the beads alerts the wearer to the presence of the radiation.
When changing colour they undergo photochromism.
When the beads are not exposed to ultraviolet rays, they are colorless and either translucent or opaque. However, when sunlight falls onto the beads, they instantly turn into red, orange, yellow, blue, purple, or pink. | 4 | Ultraviolet Radiation |
Selection favors different traits in captive populations than it does in wild populations, so this may result in adaptations that are beneficial in captivity but are deleterious in the wild. This reduces the success of re-introductions, so it is important to manage captive populations in order to reduce adaptations to captivity. Adaptations to captivity can be reduced by minimizing the number of generations in captivity and by maximizing the number of migrants from wild populations. Minimizing selection on captive populations by creating an environment that is similar to their natural environment is another method of reducing adaptations to captivity, but it is important to find a balance between an environment that minimizes adaptation to captivity and an environment that permits adequate reproduction. Adaptations to captivity can also be reduced by managing the captive population as a series of population fragments. In this management strategy, the captive population is split into several sub-populations or fragments which are maintained separately. Smaller populations have lower adaptive potentials, so the population fragments are less likely to accumulate adaptations associated with captivity. The fragments are maintained separately until inbreeding becomes a concern. Immigrants are then exchanged between the fragments to reduce inbreeding, and then the fragments are managed separately again. | 0 | Cryobiology |
Warts, moles, skin tags, solar keratoses, molluscum, Mortons neuroma and small skin cancers are candidates for cryosurgical treatment. Several internal disorders are also treated with cryosurgery, including liver cancer, prostate cancer, lung cancer, oral cancers, cervical disorders and, more commonly in the past, hemorrhoids. Soft tissue conditions such as plantar fasciitis (joggers heel) and fibroma (benign excrescence of connective tissue) can be treated with cryosurgery.
Cryosurgery works by taking advantage of the destructive force of freezing temperatures on cells. When their temperature sinks beyond a certain level ice crystals begin forming inside the cells and, because of their lower density, eventually tear apart those cells. Further harm to malignant growth will result once the blood vessels supplying the affected tissue begin to freeze.
Cryosurgery is used to treat a variety of benign skin lesions including:
* Acne
* Dermatofibroma
* Hemangioma
* Keloid (hypertrophic scar)
* Molluscum contagiosum
* Myxoid cyst
* Pyogenic granuloma
* Seborrheic keratoses
* Skin tags
* Warts (including anogenital warts)
Cryosurgery may also be used to treat low risk skin cancers such as basal cell carcinoma and squamous cell carcinoma but a biopsy should be obtained first to confirm the diagnosis, determine the depth of invasion and characterize other high risk histologic features. | 0 | Cryobiology |
In aerodynamics, hysteresis can be observed when decreasing the angle of attack of a wing after stall, regarding the lift and drag coefficients. The angle of attack at which the flow on top of the wing reattaches is generally lower than the angle of attack at which the flow separates during the increase of the angle of attack. | 3 | Magnetic Ordering |
Spin waves can propagate in magnetic media with magnetic ordering such as ferromagnets and antiferromagnets. The frequencies of the precession of the magnetisation depend on the material and its magnetic parameters, in general precession frequencies are in the microwave from 1–100 GHz, exchange resonances in particular materials can even see frequencies up to several THz. This higher precession frequency opens new possibilities for analogue and digital signal processing.
Spin waves themselves have group velocities on the order of a few km per second. The damping of spin waves in a magnetic material also causes the amplitude of the spin wave to decay with distance, meaning the distance freely propagating spin waves can travel is usually only several 10s of μm. The damping of the dynamical magnetisation is accounted for phenomenologically by the Gilbert damping constant in the Landau-Lifshitz-Gilbert equation (LLG equation), the energy loss mechanism itself is not completely understood, but is known to arise microscopically from magnon-magnon scattering, magnon-phonon scattering and losses due to eddy currents. The Landau-Lifshitz-Gilbert equation is the equation of motion for the magnetisation. All of the properties of the magnetic systems such as the applied bias field, the samples exchange, anisotropy and dipolar fields are described in terms of an effective magnetic field that enters the Landau–Lifshitz–Gilbert equation. The study of damping in magnetic systems is an ongoing modern research topic.
The LL equation was introduced in 1935 by Landau and Lifshitz to model the precessional motion of magnetization in a solid with an effective magnetic field and with damping. Later, Gilbert modified the damping term, which in the limit of small damping yields identical results. The LLG equation is,
The constant is the Gilbert phenomenological damping parameter and depends on the solid, and is the electron gyromagnetic ratio. Here
Research in magnetism, like the rest of modern science, is conducted with a symbiosis of theoretical and experimental approaches. Both approaches go hand-in-hand, experiments test the predictions of theory and theory provides explanations and predictions of new experiments. The theoretical side focuses on numerical modelling and simulations, so called micromagnetic modelling. Programs such as OOMMF or NMAG are micromagnetic solvers that numerically solve the LLG equation with appropriate boundary conditions. Prior to the start of the simulation, magnetic parameters of the sample and the initial groundstate magnetisation and bias field details are stated. | 3 | Magnetic Ordering |
Storeys research includes studies of enzyme properties, gene expression, protein phosphorylation, epigenetics, and cellular signal transduction mechanisms to seek out the basic principles of how organisms endure and flourish under extreme conditions. He is particularly known within the field of cryobiology for his studies of animals that can survive freezing, especially the frozen "frog-sicles" (Rana sylvatica) that have made his work popular with multiple TV shows and magazines. Storeys studies of the adaptations that allow frogs, insects, and other animals to survive freezing have made major advances in the understanding of how cells, tissues and organs can endure freezing. Storey was also responsible for the discovery that some turtle species are freeze tolerant: newly hatched painted turtles that spend their first winter on land (Chrysemys picta marginata & C. p. bellii). These turtles are unique as they are the only reptiles, and highest vertebrate life form, known to tolerate prolonged natural freezing of extracellular body fluids during winter hibernation. These advances may aid the development of organ cryopreservation technology. A second area of his research is metabolic rate depression - understanding the mechanisms by which some animals can reduce their metabolism and enter a state of hypometabolism or torpor that allows them to survive prolonged environmental stresses. His studies have identified molecular mechanisms that underlie metabolic arrest across phylogeny and that support phenomena including mammalian hibernation, estivation, and anoxia- and ischemia-tolerance. These studies hold key applications for medical science, particularly for preservation technologies that aim to extend the survival time of excised organs in cold or frozen storage. Additional applications include insights into hyperglycemia in metabolic syndrome and diabetes, and anoxic and ischemic damage caused by heart attack and stroke. Furthermore, Storey's lab has created several web based programs freely available for [http://www.kenstoreylab.com/research-tools/ data management, data plotting, and microRNA analysis]. | 0 | Cryobiology |
The magnetoelastic energy describes the energy storage due to elastic lattice distortions. It may be neglected if magnetoelastic coupled effects are neglected.
There exists a preferred local distortion of the crystalline solid associated with the magnetization director m, .
For a simple model, one can assume this strain to be isochoric and fully
isotropic in the lateral direction, yielding the deviatoric ansatz
where the material parameter E > 0 is the magnetostrictive
constant. Clearly, E is the strain induced by the magnetization in
the direction m. With this ansatz at hand, we consider the elastic
energy density to be a function of the elastic, stress-producing
strains . A quadratic form for the magnetoelastic energy is
where
is the fourth-order elasticity tensor. Here the elastic response is assumed to be isotropic (based on
the two Lamé constants λ and μ).
Taking into account the constant length of m, we obtain the invariant-based representation
This energy term contributes to magnetostriction. | 3 | Magnetic Ordering |
In vitro fertilisation (IVF) is a process of fertilisation where an egg is combined with sperm in vitro ("in glass"). The process involves monitoring and stimulating a womans ovulatory process, removing an ovum or ova (egg or eggs) from their ovaries and letting a mans sperm fertilise them in a culture medium in a laboratory. After the fertilised egg (zygote) undergoes embryo culture for 2–6 days, it is transferred by catheter into the uterus, with the intention of establishing a successful pregnancy.
IVF is a type of assisted reproductive technology used for infertility treatment, gestational surrogacy, and, in combination with pre-implantation genetic testing, avoiding transmission of genetic conditions. A fertilised egg from a donor may implant into a surrogate's uterus, and the resulting child is genetically unrelated to the surrogate. Some countries have banned or otherwise regulate the availability of IVF treatment, giving rise to fertility tourism. Restrictions on the availability of IVF include costs and age, in order for a person to carry a healthy pregnancy to term. Children born through IVF are colloquially called test tube babies.
In July 1978, Louise Brown was the first child successfully born after her mother received IVF treatment. 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 Edwards was awarded the Nobel Prize in Physiology or Medicine in 2010. The physiologist co-developed the treatment together with Patrick Steptoe and embryologist Jean Purdy but the latter two were not eligible for consideration as they had died and the Nobel Prize is not awarded posthumously.
Assisted by egg donation and IVF, there are many women who may be past their reproductive years, have infertile partners, have idiopathic female-fertility issues, or have reached menopause, that can still become pregnant. After the IVF treatment, some couples get pregnant without any fertility treatments. In 2023, it was estimated that twelve million children had been born worldwide using IVF and other assisted reproduction techniques. A 2019 study that explores 10 adjuncts with IVF (screening hysteroscopy, DHEA, testosterone, GH, aspirin, heparin, antioxidants, seminal plasma and PRP) suggests that until more evidence is done to show that these adjuncts are safe and effective, they should be avoided. | 0 | Cryobiology |
The categorization of amylopectin began with the first observation in starch in 1716 by Antonie van Leeuwenhoek, where he differentiated starch into two fundamental structural components.
The terms amylose and amylopectin where not coined until 1906, by French researchers Maquenee and Roux in the course of an examination of starch, where they explained variations in the properties of starches according to the mixture of these related substances and variable saccharification by malt extract. Since then and through the 1940s, research focused on various methods of separation, like fractional precipitation or enzymatically. This gave rise to the Meyer definition of amylose and "reserv[ing] the name amylopectin to carbohydrates that are branched molecule, degraded by b-amylase only to the stage of residual dextrin". Meyer also proposed the tree like structure model for amylopectin.
The currently accepted structural model was proposed in 1972, based on the cluster organization of double helical structures. Other models have been proposed since, such as the Bertoft BB model, or building block and backbone model in 2012. This model claims short chains are the structural building blocks and long chains the backbone to carry the building blocks, and that the different lengths of chain are separated by their position and direction of elongation | 2 | Carbohydrates |
Sedimentation in potable water treatment generally follows a step of chemical coagulation and flocculation, which allows grouping particles together into flocs of a bigger size. This increases the settling speed of suspended solids and allows settling colloids. | 1 | Separation Processes |
DEHPA is used in the solvent extraction of uranium salts from solutions containing the sulfate, chloride, or perchlorate anions. This extraction is known as the “Dapex procedure” (dialkyl phosphoric extraction). Reminiscent of the behaviours of carboxylic acids, DEHPA generally exists as a hydrogen-bonded dimer in the non-polar organic solvents. For practical applications, the solvent, often called a diluent, is typically kerosene. A complex is formed from two equivalents of the conjugate base of DEHPA and one uranyl ion. Complexes of the formula (UO)[(OP(OR)] also form, and at high concentrations of uranium, polymeric complexes may form.
The extractability of Fe is similar to that of uranium, so it must be reduced to Fe before the extraction. | 1 | Separation Processes |
UV/Vis spectroscopy is widely used as a technique in chemistry to analyze chemical structure, the most notable one being conjugated systems. UV radiation is often used to excite a given sample where the fluorescent emission is measured with a spectrofluorometer. In biological research, UV radiation is used for quantification of nucleic acids or proteins. In environmental chemistry, UV radiation could also be used to detect Contaminants of emerging concern in water samples.
In pollution control applications, ultraviolet analyzers are used to detect emissions of nitrogen oxides, sulfur compounds, mercury, and ammonia, for example in the flue gas of fossil-fired power plants. Ultraviolet radiation can detect thin sheens of spilled oil on water, either by the high reflectivity of oil films at UV wavelengths, fluorescence of compounds in oil, or by absorbing of UV created by Raman scattering in water. UV absorbance can also be uesd to quantify contaminants in wastewater. Most commonly used 254 nm UV absorbance is genrally used as a surrogate parameters to quantify NOM. Another form of light-based detection method uses a wide spectrum of excitation emission matrix (EEM) to detect and identify contaminants based on their flourense properties. EEM could be used to discriminate different groups of NOM based on the difference in light emission and excitation of fluorophores. NOMs with certain molecular structures are reported to have fluorescent properties in a wide range of excitation/emission wavelengths.
Ultraviolet lamps are also used as part of the analysis of some minerals and gems. | 4 | Ultraviolet Radiation |
Piezomagnetism is a phenomenon observed in some antiferromagnetic and ferrimagnetic crystals. It is characterized by a linear coupling between the system's magnetic polarization and mechanical strain. In a piezomagnetic material, one may induce a spontaneous magnetic moment by applying mechanical stress, or a physical deformation by applying a magnetic field.
Piezomagnetism differs from the related property of magnetostriction; if an applied magnetic field is reversed in direction, the strain produced changes signs. Additionally, a non-zero piezomagnetic moment can be produced by mechanical strain alone, at zero fields, which is not true of magnetostriction. According to the Institute of Electrical and Electronics Engineers (IEEE):
The piezomagnetic effect is made possible by an absence of certain symmetry elements in a crystal structure; specifically, symmetry under time reversal forbids the property.
The first experimental observation of piezomagnetism was made in 1960, in the fluorides of cobalt and manganese.
The strongest piezomagnet known is uranium dioxide, with magnetoelastic memory switching at magnetic fields near 180,000 Oe at temperatures below 30 kelvins. | 3 | Magnetic Ordering |
Solid carbon dioxide (dry ice) sublimes rapidly along the solid-gas boundary (sublimation point) below the triple point (e.g., at the temperature of −78.5 °C, at atmospheric pressure), whereas its melting into liquid CO can occur along the solid-liquid boundary (melting point) at pressures and temperatures above the triple point (i.e., 5.1 atm, −56.6 °C). | 1 | Separation Processes |
Energy recovery can reduce energy consumption by 50% or more. Much of the input energy can be recovered from the concentrate flow, and the increasing efficiency of energy recovery devices greatly reduces energy requirements. Devices used, in order of invention, are:
* Turbine or Pelton wheel: a water turbine driven by the concentrate flow, connected to the pump drive shaft provides part of the input power. Positive displacement axial piston motors have been used in place of turbines on smaller systems.
* Turbocharger: a water turbine driven by concentrate flow, directly connected to a centrifugal pump that boosts the output pressure, reducing the pressure needed from the pump and thereby its energy input, similar in construction principle to car engine turbochargers.
* Pressure exchanger: using the pressurized concentrate flow, via direct contact or a piston, to pressurize part of the membrane feed flow to near concentrate flow pressure. A boost pump then raises this pressure by typically 3 bar / 50 psi to the membrane feed pressure. This reduces flow needed from the high-pressure pump by an amount equal to the concentrate flow, typically 60%, and thereby its energy input. These are widely used on larger low-energy systems. They are capable of 3 kWh/m or less energy consumption.
* Energy-recovery pump: a reciprocating piston pump. The pressurized concentrate flow is applied to one side of each piston to help drive the membrane feed flow from the opposite side. These are the simplest energy recovery devices to apply, combining the high pressure pump and energy recovery in a single self-regulating unit. These are widely used on smaller low-energy systems. They are capable of 3 kWh/m or less energy consumption.
* Batch operation: RO systems run with a fixed volume of fluid (thermodynamically a closed system) do not suffer from wasted energy in the brine stream, as the energy to pressurize a virtually incompressible fluid (water) is negligible. Such systems have the potential to reach second-law efficiencies of 60%. | 1 | Separation Processes |
One last area that has been actively studied is the synergy of different materials in promoting superior electroactive performance. Whether through various charge transport material, electrochemical species, or morphologies, exploiting the synergetic relationship between different materials has paved the way for even newer counter electrode materials.
In 2016, Lu et al. mixed nickel cobalt sulfide microparticles with reduced graphene oxide (rGO) nanoflakes to create the counter electrode. Lu et al. discovered not only that the rGO acted as a co-catalyst in accelerating the triiodide reduction, but also that the microparticles and rGO had a synergistic interaction that decreased the charge transfer resistance of the overall system. Although the efficiency of this system was slightly lower than its platinum analog (efficiency of NCS/rGO system: 8.96%; efficiency of Pt system: 9.11%), it provided a platform on which further research can be conducted. | 4 | Ultraviolet Radiation |
In the presence of a uniform external magnetic field along the z-direction, the Hamiltonian of the atom changes by
where are positive real numbers which are independent of which atom we are looking at but depend on the mass and the charge of the electron. corresponds to individual electrons of the atom.
We apply second order perturbation theory to this situation. This is justified by the fact that even for highest presently attainable field strengths, the shifts in the energy level due to is quite small w.r.t. atomic excitation energies. Degeneracy of the original Hamiltonian is handled by choosing a basis which diagonalizes in the degenerate subspaces. Let be such a basis for the state of the atom (rather the electrons in the atom). Let be the change in energy in . So we get
In our case we can ignore and higher order terms. We get
In case of diamagnetic material, the first two terms are absent as they don't have any angular momentum in their ground state. In case of paramagnetic material all the three terms contribute. | 3 | Magnetic Ordering |
Pregnancy rate may be defined in various ways. In the United States, SART and the Centers for Disease Control (and appearing in the table in the Success Rates section above) include statistics on positive pregnancy test and clinical pregnancy rate.
The 2019 summary compiled by the SART the following data for non-donor eggs (first embryo transfer) in the United States:
In 2006, Canadian clinics reported an average pregnancy rate of 35%. A French study estimated that 66% of patients starting IVF treatment finally succeed in having a child (40% during the IVF treatment at the centre and 26% after IVF discontinuation). Achievement of having a child after IVF discontinuation was mainly due to adoption (46%) or spontaneous pregnancy (42%). | 0 | Cryobiology |
Crystallization requires an initiation step. This can be spontaneous or can be done by adding a small amount of the pure compound (a seed crystal) to the saturated solution, or can be done by simply scratching the glass surface to create a seeding surface for crystal growth. It is thought that even dust particles can act as simple seeds. | 1 | Separation Processes |
In scientific literature, the term "carbohydrate" has many synonyms, like "sugar" (in the broad sense), "saccharide", "ose", "glucide", "hydrate of carbon" or "polyhydroxy compounds with aldehyde or ketone". Some of these terms, especially "carbohydrate" and "sugar", are also used with other meanings.
In food science and in many informal contexts, the term "carbohydrate" often means any food that is particularly rich in the complex carbohydrate starch (such as cereals, bread and pasta) or simple carbohydrates, such as sugar (found in candy, jams, and desserts). This informality is sometimes confusing since it confounds chemical structure and digestibility in humans.
Often in lists of nutritional information, such as the USDA National Nutrient Database, the term "carbohydrate" (or "carbohydrate by difference") is used for everything other than water, protein, fat, ash, and ethanol. This includes chemical compounds such as acetic or lactic acid, which are not normally considered carbohydrates. It also includes dietary fiber which is a carbohydrate but which does not contribute food energy in humans, even though it is often included in the calculation of total food energy just as though it did (i.e., as if it were a digestible and absorbable carbohydrate such as a sugar).
In the strict sense, "sugar" is applied for sweet, soluble carbohydrates, many of which are used in human food. | 2 | Carbohydrates |
Systems with rate-independent hysteresis have a persistent memory of the past that remains after the transients have died out. The future development of such a system depends on the history of states visited, but does not fade as the events recede into the past. If an input variable cycles from to and back again, the output may be initially but a different value upon return. The values of depend on the path of values that passes through but not on the speed at which it traverses the path. Many authors restrict the term hysteresis to mean only rate-independent hysteresis. Hysteresis effects can be characterized using the Preisach model and the generalized Prandtl−Ishlinskii model. | 3 | Magnetic Ordering |
In the laboratory, for ICSI treatments, the identified eggs are stripped of surrounding cells (also known as cumulus cells) and prepared for fertilisation. An oocyte selection may be performed prior to fertilisation to select eggs that can be fertilised, as it is required they are in metaphase II. There are cases in which if oocytes are in the metaphase I stage, they can be kept being cultured so as to undergo a posterior sperm injection. In the meantime, semen is prepared for fertilisation by removing inactive cells and seminal fluid in a process called sperm washing. If semen is being provided by a sperm donor, it will usually have been prepared for treatment before being frozen and quarantined, and it will be thawed ready for use. | 0 | Cryobiology |
A hysteresis effect may be observed in voicing onset versus offset. The threshold value of the subglottal pressure required to start the vocal fold vibration is lower than the threshold value at which the vibration stops, when other parameters are kept constant. In utterances of vowel-voiceless consonant-vowel sequences during speech, the intraoral pressure is lower at the voice onset of the second vowel compared to the voice offset of the first vowel, the oral airflow is lower, the transglottal pressure is larger and the glottal width is smaller. | 3 | Magnetic Ordering |
Trehalose is a disaccharide formed by a bond between two α-glucose units. It is found in nature as a disaccharide and also as a monomer in some polymers. Two other isomers exist, α,β-trehalose, otherwise known as neotrehalose, and β,β-trehalose (also referred to as isotrehalose). Neotrehalose has not been isolated from a living organism. Isotrehalose is also yet to be isolated from a living organism, but was found in starch hydroisolates. | 2 | Carbohydrates |
Exposure to ultraviolet radiation (UVR), whether from the sun or tanning devices is known to be a major cause of the three main types of skin cancer: non-melanoma skin cancer (basal cell carcinoma and squamous cell carcinoma) and melanoma. Overexposure to UVR induces at least two types of DNA damage: cyclobutane–pyrimidine dimers (CPDs) and 6–4 photoproducts (6–4PPs). While DNA repair enzymes can fix some mutations, if they are not sufficiently effective, a cell will acquire genetic mutations which may cause the cell to die or become cancerous. These mutations can result in cancer, aging, persistent mutation and cell death. For example, squamous cell carcinoma can be caused by a UVB-induced mutation in the p53 gene.
Non-melanoma skin cancer includes squamous cell carcinoma (SCC) and basal cell carcinoma (BCC), and is more common than melanoma. With early detection and treatment, it is typically not life-threatening. Prevalence increases with age, cumulative exposure to UV, and proximity to the equator. It is most prevalent in Australia, where the rate is 1,000 in 100,000 and where, as of 2000, it represented 75 percent of all cancers.
Melanoma accounts for approximately one percent of skin cancer, and causes most of skin cancer-related deaths. The average age of diagnosis is 63, and it is the most common cancer in the 25–29 age group and the second most common in the 15-29 group, which may be due in part to the increased UV exposure and use of indoor tanning observed in this population. In the United States, the melanoma incidence rate was 22.3 per 100,000, based on 2010–2014 data from the National Institutes of Health Surveillance, Epidemiology and End Results (SEER) Program, and the death rate was 2.7 per 100,000. 9,730 people were estimated to die of melanoma in the United States in 2017, and these numbers are anticipated to continue rising. Although 91.7% of patients diagnosed with melanoma survive beyond 5-years, advanced melanoma is largely incurable, and only 19.9% percent of patients with metastatic disease survive beyond 5 years. An international meta-analysis performed in 2014 estimates that annually, 464,170 cases of skin cancer can be attributed to exposure to indoor tanning.
A 2012 analysis of epidemiological studies found a 20% increase in the risk of melanoma (a relative risk of 1.20) among those who had ever used a tanning device compared to those who had not, and a 59% percent increase (a relative risk of 1.59) among those who had used one before age 35. Additionally, a 2014 systematic review and meta-analysis found that indoor tanners had a 16 percent increased risk of developing melanoma, which increased to 23 percent for North Americans. For those who started tanning indoors before age 25, their risk further increased to 35% compared to those who began after age 25. | 4 | Ultraviolet Radiation |
Vitrification in cryopreservation is used to preserve, for example, human egg cells (oocytes) (in oocyte cryopreservation) and embryos (in embryo cryopreservation). It prevents ice crystal formation and is a very fast process: -23,000°C/min.
Currently, vitrification techniques have only been applied to brains (neurovitrification) by Alcor and to the upper body by the Cryonics Institute, but research is in progress by both organizations to apply vitrification to the whole body.
Many woody plants living in polar regions naturally vitrify their cells to survive the cold. Some can survive immersion in liquid nitrogen and liquid helium. Vitrification can also be used to preserve endangered plant species and their seeds. For example, recalcitrant seeds are considered hard to preserve. Plant vitrification solution (PVS), one of application of vitrification, has successfully preserved Nymphaea caerulea seeds.
Additives used in cryobiology or produced naturally by organisms living in polar regions are called cryoprotectants. | 0 | Cryobiology |
Snow and ice sublime gradually at temperatures below the solid-liquid boundary (melting point) (generally 0 °C), and at partial pressures below the triple point pressure of , at a low rate. In freeze-drying, the material to be dehydrated is frozen and its water is allowed to sublime under reduced pressure or vacuum. The loss of snow from a snowfield during a cold spell is often caused by sunshine acting directly on the upper layers of the snow. Sublimation of ice is a factor to the erosive wear of glacier ice, also called ablation in glaciology. | 1 | Separation Processes |
The use of glucosinolate-containing crops as primary food source for animals can have negative effects if the concentration of glucosinolate is higher than what is acceptable for the animal in question, because some glucosinolates have been shown to have toxic effects (mainly as goitrogens and anti-thyroid agents) in livestock at high doses. However, tolerance level to glucosinolates varies even within the same genus (e.g. Acomys cahirinus and Acomys russatus).
Dietary amounts of glucosinolate are not toxic to humans given normal iodine intake. | 2 | Carbohydrates |
Methanediol, also known as formaldehyde monohydrate or methylene glycol, is an organic compound with chemical formula . It is the simplest geminal diol. In aqueous solutions it coexists with oligomers (short polymers). The compound is closely related and convertible to the industrially significant derivatives paraformaldehyde (), formaldehyde (), and 1,3,5-trioxane ().
Methanediol is a product of the hydration of formaldehyde. The equilibrium constant for hydration is estimated to be 10, predominates in dilute (<0.1%) solution. In more concentrated solutions, it oligomerizes to . | 2 | Carbohydrates |
An example of magnetoresistance due to direct action of magnetic field on electric current can be studied on a Corbino disc (see Figure).
It consists of a conducting annulus with perfectly conducting rims. Without a magnetic field, the battery drives a radial current between the rims. When a magnetic field perpendicular to the plane of the annulus is applied, (either into or out of the page) a circular component of current flows as well, due to Lorentz force. Initial interest in this problem began with Boltzmann in 1886, and independently was re-examined by Corbino in 1911.
In a simple model, supposing the response to the Lorentz force is the same as for an electric field, the carrier velocity v is given by:
where μ is the carrier mobility. Solving for the velocity, we find:
where the effective reduction in mobility due to the B-field (for motion perpendicular to this field) is apparent. Electric current (proportional to the radial component of velocity) will decrease with increasing magnetic field and hence the resistance of the device will increase. Critically, this magnetoresistive scenario depends sensitively on the device geometry and current lines and it does not rely on magnetic materials.
In a semiconductor with a single carrier type, the magnetoresistance is proportional to (1 + (μB)), where μ is the semiconductor mobility (units m·V·s or T) and B is the magnetic field (units teslas). Indium antimonide, an example of a high mobility semiconductor, could have an electron mobility above 4 m·V·s at 300 K. So in a 0.25 T field, for example the magnetoresistance increase would be 100%. | 3 | Magnetic Ordering |
A germicidal lamp (also known as disinfection lamp or sterilizer lamp) is an electric light that produces ultraviolet C (UVC) light. This short-wave ultraviolet light disrupts DNA base pairing, causing formation of pyrimidine dimers, and leads to the inactivation of bacteria, viruses, and protozoans. It can also be used to produce ozone for water disinfection. They are used in ultraviolet germicidal irradiation (UVGI).
There are four common types available:
* Low-pressure mercury lamps
* High-pressure mercury lamps
* Excimer lamps
* LEDs | 4 | Ultraviolet Radiation |
Ovarian hyperstimulation is the stimulation to induce development of multiple follicles of the ovaries. It should start with response prediction by e.g. age, antral follicle count and level of anti-Müllerian hormone. The resulting prediction of e.g. poor or hyper-response to ovarian hyperstimulation determines the protocol and dosage for ovarian hyperstimulation.
Ovarian hyperstimulation also includes suppression of spontaneous ovulation, for which two main methods are available: Using a (usually longer) GnRH agonist protocol or a (usually shorter) GnRH antagonist protocol. In a standard long GnRH agonist protocol the day when hyperstimulation treatment is started and the expected day of later oocyte retrieval can be chosen to conform to personal choice, while in a GnRH antagonist protocol it must be adapted to the spontaneous onset of the previous menstruation. On the other hand, the GnRH antagonist protocol has a lower risk of ovarian hyperstimulation syndrome (OHSS), which is a life-threatening complication.
For the ovarian hyperstimulation in itself, injectable gonadotropins (usually FSH analogues) are generally used under close monitoring. Such monitoring frequently checks the estradiol level and, by means of gynecologic ultrasonography, follicular growth. Typically approximately 10 days of injections will be necessary.
When stimulating ovulation after suppressing endogenous secretion, it is necessary to supply exogenous gonadotropines. The most common one is the human menopausal gonadotropin (hMG), which is obtained by donation of menopausal women. Other pharmacological preparations are FSH+LH or coripholitropine alpha. | 0 | Cryobiology |
In many materials, the Curie–Weiss law fails to describe the susceptibility in the immediate vicinity of the Curie point, since it is based on a mean-field approximation. Instead, there is a critical behavior of the form
with the critical exponent . However, at temperatures the expression of the Curie–Weiss law still holds true, but with replaced by a temperature that is somewhat higher than the actual Curie temperature. Some authors call the Weiss constant to distinguish it from the temperature of the actual Curie point. | 3 | Magnetic Ordering |
Unlike most other commodity plastics polyethylene terephthalate (PET) is able to absorb the near ultraviolet rays in sunlight. Absorption begins at 360 nm, becoming stronger below 320 nm and is very significant below 300 nm. Despite this PET has better resistance to photo-oxidation than other commodity plastics, this is due to a poor quantum yield or the absorption. The degradation chemistry is complicated due to simultaneous photodissociation (i.e. not involving oxygen) and photo-oxidation reactions of both the aromatic and aliphatic parts of the molecule. Chain scission is the dominant process, with chain branching and the formation of coloured impurities being less common. Carbon monoxide, carbon dioxide, and carboxylic acids are the main products.
The photo-oxidation of other linear polyesters such as polybutylene terephthalate and polyethylene naphthalate proceeds similarly.
Photodissociation involves the formation of an excited terephthalic acid unit which undergoes Norrish reactions. The type I reaction dominates, which cause chain scission at the carbonyl unit to give a range of products.
Type II Norrish reactions are less common but give rise to acetaldehyde by way of vinyl alcohol esters. This has an exceedingly low odour and taste threshold and can cause an off-taste in bottled water.
Radicals formed by photolysis may initiate the photo-oxidation in PET. Photo-oxidation of the aromatic terephthalic acid core results in its step-wise oxidation to 2,5-dihydroxyterephthalic acid. The photo-oxidation process at aliphatic sites is similar to that seen for polyolefins, with the formation of hydroperoxide species eventually leading to beta-scission of the polymer chain. | 4 | Ultraviolet Radiation |
Embryo transfer can be performed after various durations of embryo culture, conferring different stages in embryogenesis. The main stages at which embryo transfer is performed are cleavage stage (day 2 to 4 after co-incubation) or the blastocyst stage (day 5 or 6 after co-incubation).
Because in vivo, a cleavage stage embryo still resides in the fallopian tube and it is known that the nutritional environment of the uterus is different from that of the tube, it is postulated that this may cause stress on the embryo if transferred on day 3 resulting in reduced implantation potential. A blastocyst stage embryo does not have this problem as it is best suited for the uterine environment [https://www.cochranelibrary.com/cdsr/doi/10.1002/14651858.CD002118.pub5/full]
Embryos who reach the day 3 cell stage can be tested for chromosomal or specific genetic defects prior to possible transfer by preimplantation genetic diagnosis (PGD). Transferring at the blastocyst stage confers a significant increase in live birth rate per transfer, but also confers a decreased number of embryos available for transfer and embryo cryopreservation, so the cumulative clinical pregnancy rates are increased with cleavage stage transfer. It is uncertain whether there is any difference in live birth rate between transfer on day two or day three after fertilization.
Monozygotic twinning is not increased after blastocyst transfer compared with cleavage-stage embryo transfer.
There is a significantly higher odds of preterm birth (odds ratio 1.3) and congenital anomalies (odds ratio 1.3) among births having reached the blastocyst stage compared with cleavage stage. Because of increased female embryo mortality due to epigenetic modifications induced by extended culture, blastocyst transfer leads to more male births (56.1% male) versus 2 or 3 day transfer (a normal sex ratio of 51.5% male). | 0 | Cryobiology |
Lectins are carbohydrate-binding proteins that are highly specific for sugar groups that are part of other molecules, so cause agglutination of particular cells or precipitation of glycoconjugates and polysaccharides. Lectins have a role in recognition at the cellular and molecular level and play numerous roles in biological recognition phenomena involving cells, carbohydrates, and proteins. Lectins also mediate attachment and binding of bacteria, viruses, and fungi to their intended targets.
Lectins are found in many foods. Some foods, such as beans and grains, need to be cooked, fermented or sprouted to reduce lectin content. Some lectins are beneficial, such as CLEC11A, which promotes bone growth, while others may be powerful toxins such as ricin.
Lectins may be disabled by specific mono- and oligosaccharides, which bind to ingested lectins from grains, legumes, nightshade plants, and dairy; binding can prevent their attachment to the carbohydrates within the cell membrane. The selectivity of lectins means that they are useful for analyzing blood type, and they have been researched for potential use in genetically engineered crops to transfer pest resistance. | 2 | Carbohydrates |
Aqueous biphasic systems (ABS) or aqueous two-phase systems (ATPS) are clean alternatives for traditional organic-water solvent extraction systems.
ABS are formed when either two polymers, one polymer and one kosmotropic salt, or two salts (one chaotropic salt and the other a kosmotropic salt) are mixed at appropriate concentrations or at a particular temperature. The two phases are mostly composed of water and non volatile components, thus eliminating volatile organic compounds. They have been used for many years in biotechnological applications as non-denaturing and benign separation media. Recently, it has been found that ATPS can be used for separations of metal ions like mercury and cobalt, carbon nanotubes, environmental remediation, metallurgical applications and as a reaction media. | 1 | Separation Processes |
Vaporization (from liquid to gas) is divided into two types: vaporization on the surface of the liquid is called evaporation, and vaporization at the boiling point with formation of bubbles in the interior of the liquid is called boiling. However there is no such distinction for the solid-to-gas transition, which is always called sublimation in both corresponding cases. | 1 | Separation Processes |
The main advantage over other filtration systems is the reduction in energy consumption, up to 90% because no air flows through the discs due to the use of capillary force acting on the pores. Air breakthrough is prevented by the fine pores of the filter, thus allowing retention of higher vacuum levels. Therefore, the vacuum losses are less, which means the vacuum pump required is smaller than in conventional disc filters, thus minimizing operating costs. Power consumed by a vacuum ceramic filter with 45 m of filtration area is 15 kW while 170 kW is consumed by similar filters with cloth membranes.
Generally, conventional disc filters are not suitable for cake washing because the water quickly runs off the surface of the cake. As the cake solids are sprayed with a wash liquid to remove impurities, they are not suitable for conventional filtration systems where channelling or uneven distribution occurs, leading to cake cracking. However, cake washing has been proved to be more efficient with vacuum ceramic filters due to the steady flow profile and the even distribution of the cake.
A further advantage of vacuum ceramic filter is the high output capacity with a very low water content and drier filter cake. By comparison, the performance of a VDFK-3 ceramic filter was compared with the existing BOU-40 and BLN40-3 drum type vacuum filters to filter aluminium hydroxide. From the results, the average moisture content was 5% (abs? or rel?) lower when a vacuum ceramic filter was used.
Vacuum ceramic filters also have a longer service life while cloth filters have to be replaced, which eventually increases the moisture content of the cake, lowers the productivity and disturbs the production operations. In addition, the ceramic filter is both mechanically and chemically reliable enough to withstand regeneration.
Whilst the vacuum ceramic filter has proved to be a great innovation, there are still some limitations involved when operating the equipment. Ceramic filters exhibit large fluctuations in the recoiling washing pressure (0.05~0.35 MPa). This raises the short-term negative pressure and induces dilute acid due to the falling suck phenomenon. Therefore, the cleaning effect of the ceramic plates and the efficiency of the filter will be negatively affected. | 1 | Separation Processes |
Mercury lamps are the most common source of UV radiation due to their high efficiency. However, the use of mercury in these lamps poses disposal and environmental problems. On the contrary, excimer lamps based on rare gases are absolutely non-hazardous and excimer lamps containing halogen are more environmentally benign than mercury ones. | 4 | Ultraviolet Radiation |
A low-FODMAP diet might help to improve short-term digestive symptoms in adults with functional abdominal bloating and irritable bowel syndrome, but its long-term use can have negative effects because it causes a detrimental impact on the gut microbiota and metabolome. It should only be used for short periods of time and under the advice of a specialist. More studies are needed to evaluate its effectiveness in children with irritable bowel syndrome.
There is only a little evidence of its effectiveness in treating functional symptoms in inflammatory bowel disease from small studies that are susceptible to bias. More studies are needed to assess the true impact of this diet on health.
In addition, the use of a low-FODMAP diet without medical advice can lead to serious health risks, including nutritional deficiencies and misdiagnosis, so it is advisable to conduct a complete medical evaluation before starting a low-FODMAP diet to ensure a correct diagnosis and that the appropriate therapy may be undertaken.
Since the consumption of gluten is suppressed or reduced with a low-FODMAP diet, the improvement of the digestive symptoms with this diet may not be related to the withdrawal of the FODMAPs, but of gluten, indicating the presence of an unrecognized celiac disease, avoiding its diagnosis and correct treatment, with the consequent risk of several serious health complications, including various types of cancer.
A low-FODMAP diet is highly restrictive in various groups of nutrients, can be impractical to follow in the long-term and may add an unnecessary financial burden. | 2 | Carbohydrates |
Medium-pressure mercury-vapor lamps have historically been the industry standard for curing products with ultraviolet light. The bulbs work by sending an electric discharge to excite a mixture of mercury and noble gases, generating a plasma. Once the mercury reaches a plasma state, it irradiates a high spectral output in the UV region of the electromagnetic spectrum. Major peaks in light intensity occur in the 240-270 nm and 350-380 nm regions. These intense peaks, when matched with the absorption profile of a photoinitiator, cause the rapid curing of materials. By modifying the bulb mixture with different gases and metal halides, the distribution of wavelength peaks can be altered, and material interactions are changed.
Medium-pressure lamps can either be standard gas-discharge lamps or electrodeless lamps, and typically use an elongated bulb to emit energy. By incorporating optical designs such an elliptical or even aconic reflector, light can either be focused or projected over a far distance. These lamps can often operate at over 900 degrees Celsius and produce UV energy levels over 10 W/cm. | 4 | Ultraviolet Radiation |
Sizing of a UV system is affected by three variables: flow rate, lamp power, and UV transmittance in the water. Manufacturers typically developed sophisticated computational fluid dynamics (CFD) models validated with bioassay testing. This involves testing the UV reactor's disinfection performance with either MS2 or T1 bacteriophages at various flow rates, UV transmittance, and power levels in order to develop a regression model for system sizing. For example, this is a requirement for all public water systems in the United States per the EPA UV manual.
The flow profile is produced from the chamber geometry, flow rate, and particular turbulence model selected. The radiation profile is developed from inputs such as water quality, lamp type (power, germicidal efficiency, spectral output, arc length), and the transmittance and dimension of the quartz sleeve. Proprietary CFD software simulates both the flow and radiation profiles. Once the 3D model of the chamber is built, it is populated with a grid or mesh that comprises thousands of small cubes.
Points of interest—such as at a bend, on the quartz sleeve surface, or around the wiper mechanism—use a higher resolution mesh, whilst other areas within the reactor use a coarse mesh. Once the mesh is produced, hundreds of thousands of virtual particles are "fired" through the chamber. Each particle has several variables of interest associated with it, and the particles are "harvested" after the reactor. Discrete phase modeling produces delivered dose, head loss, and other chamber-specific parameters. | 4 | Ultraviolet Radiation |
The Endocare PerCryo Percutaneous Cryoablation device utilizes argon as a coolant and can be used with four different single cryoprobe configurations with a diameter of either 1.7 mm (~16 gauge) or 2.4 mm (~13 gauge) in diameter .
The Myoscience Iovera is a handheld device that uses nitrous oxide as a coolant and can be used with a three-probe configuration with a probe diameter of 0.4 mm (~27 gauge). | 0 | Cryobiology |
The technique of selecting only one embryo to transfer to the woman is called elective-single embryo transfer (e-SET) or, when embryos are at the blastocyst stage, it can also be called elective single blastocyst transfer (eSBT). It significantly lowers the risk of multiple pregnancies, compared with e.g. Double Embryo Transfer (DET) or double blastocyst transfer (2BT), with a twinning rate of approximately 3.5% in sET compared with approximately 38% in DET, or 2% in eSBT compared with approximately 25% in 2BT. At the same time, pregnancy rates is not significantly less with eSBT than with 2BT. That is, the cumulative live birth rate associated with single fresh embryo transfer followed by a single frozen and thawed embryo transfer is comparable with that after one cycle of double fresh embryo transfer. Furthermore, SET has better outcomes in terms of mean gestational age at delivery, mode of delivery, birthweight, and risk of neonatal intensive care unit necessity than DET. e-SET of embryos at the cleavage stage reduces the likelihood of live birth by 38% and multiple birth by 94%. Evidence from randomized, controlled trials suggests that increasing the number of e-SET attempts (fresh and/or frozen) results in a cumulative live birth rate similar to that of DET.
The usage of single embryo transfer is highest in Sweden (69.4%), but as low as 2.8% in the USA. Access to public funding for ART, availability of good cryopreservation facilities, effective education about the risks of multiple pregnancy, and legislation appear to be the most important factors for regional usage of single embryo transfer. Also, personal choice plays a significant role as many subfertile couples have a strong preference for twins. | 0 | Cryobiology |
Hypothermia therapy for neonatal encephalopathy has been proven to improve outcomes for newborn infants affected by perinatal hypoxia-ischemia, hypoxic ischemic encephalopathy or birth asphyxia. A 2013 Cochrane review found that it is useful in full term babies with encephalopathy. Whole body or selective head cooling to , begun within six hours of birth and continued for 72 hours, reduces mortality and reduces cerebral palsy and neurological deficits in survivors. | 0 | Cryobiology |
Due to the very low temperatures required, varying levels of stress are put on the DNA samples. Spermatozoa, in particular, are stressed by temperature shock, osmotic stress, and oxidative stress with the latter being the most detrimental. When temperature shock occurs, the membrane is damaged through freezing and thawing of the sperm. Osmotic stress occurs when ice crystals form inside the nucleus during the freezing process, causing differing osmotic pressures within the cell. Oxidative stress is the result of too many reactive oxygen species (ROS), which is highly reactive and damaging to all parts of the cell. Although these stressors are present within the cell, there are solutions to each. By introducing cholesterol to the samples, temperature shock can be reduced. The use of antifreeze proteins provides one solution for osmotic stress. Oxidative stress is the most difficult to combat because of the highly reactive components of ROS, but some measures like adding certain proteins to limit freeze-thaw damage and increase the survival rate of the DNA. | 0 | Cryobiology |
FODMAPs present in gluten-containing grains have been identified as a possible cause of gastrointestinal symptoms in people with non-celiac gluten sensitivity, either by themselves, or in combination effect with gluten and other proteins in gluten-containing cereals, such as amylase-trypsin inhibitors (ATIs). The amount of fructans in these cereals is small. In rye, they account for 3.6–6.6% of dry matter, 0.7–2.9% in wheat, and barley contains only trace amounts. They are only minor sources of FODMAPs when eaten in common dietary amounts. Wheat and rye may comprise a major source of fructans when consumed in large amounts.
In a 2018 double-blind, crossover research study on 59 persons on a gluten-free diet with challenges of gluten, fructans, or placebo, intestinal symptoms (specifically bloating) were (borderline) significantly higher after challenge with fructans, in comparison with gluten proteins (P=0.049). Although the differences between the three interventions were small, the authors concluded that fructans are more likely to cause gastrointestinal symptoms in non-celiac gluten sensitivity than gluten. Fructans used in the study were extracted from chicory root, and the results may or may not apply to wheat fructans.
A 2018 review concluded that although fructan intolerance may play a role in non-celiac gluten sensitivity, it only explains some gastrointestinal symptoms. Fructan intolerance does not explain the extra-digestive symptoms that people with non-celiac gluten sensitivity may develop, such as neurological disorders, fibromyalgia, psychological disturbances, and dermatitis. This review also found that FODMAPs may cause digestive symptoms when the person is hypersensitive to luminal distension.
A 2019 review concluded that wheat fructans could cause certain IBS-like symptoms, such as bloating, but that they are not likely to cause immune activation or extra-digestive symptoms, as many people with non-celiac gluten sensitivity reported resolution of their symptoms after removing gluten-containing cereals. These same participants continued to eat fruits and vegetables with high FODMAP content without issue. | 2 | Carbohydrates |
The magnetocrystalline anisotropy parameters have a strong dependence on temperature. They generally decrease rapidly as the temperature approaches the Curie temperature, so the crystal becomes effectively isotropic. Some materials also have an isotropic point at which . Magnetite (), a mineral of great importance to rock magnetism and paleomagnetism, has an isotropic point at 130 kelvin.
Magnetite also has a phase transition at which the crystal symmetry changes from cubic (above) to monoclinic or possibly triclinic below. The temperature at which this occurs, called the Verwey temperature, is 120 Kelvin. | 3 | Magnetic Ordering |
FODMAPs or fermentable oligosaccharides, disaccharides, monosaccharides, and polyols are short-chain carbohydrates that are poorly absorbed in the small intestine and ferment in the colon. They include short-chain oligosaccharide polymers of fructose (fructans) and galactooligosaccharides (GOS, stachyose, raffinose), disaccharides (lactose), monosaccharides (fructose), and sugar alcohols (polyols), such as sorbitol, mannitol, xylitol, and maltitol. Most FODMAPs are naturally present in food and the human diet, but the polyols may be added artificially in commercially prepared foods and beverages.
FODMAPs may cause digestive discomfort in some people. The reasons are hypersensitivity to luminal distension and/or a proclivity to excess water retention and gas production and accumulation, but they do not cause intestinal inflammation. Naturally occurring FODMAPs may help avert digestive discomfort for some people because they produce beneficial alterations in the gut flora. They are not the cause of these disorders, but a low-FODMAP diet, restricting FODMAPs, might help to improve digestive symptoms in adults with irritable bowel syndrome (IBS) and other functional gastrointestinal disorders (FGID). Avoiding all FODMAPs long-term may have a detrimental impact on the gut microbiota and metabolome.
FODMAPs, especially fructans, are present in small amounts in gluten-containing grains and have been identified as a possible cause of symptoms in people with non-celiac gluten sensitivity. They are only minor sources of FODMAPs when eaten in the usual standard quantities in the daily diet. As of 2019, reviews conclude that although FODMAPs present in wheat and related grains may play a role in non-celiac gluten sensitivity, they only explain certain gastrointestinal symptoms, such as bloating, but not the extra-digestive symptoms that people with non-celiac gluten sensitivity may develop, such as neurological disorders, fibromyalgia, psychological disturbances, and dermatitis. Consuming a low FODMAP diet without a previous medical evaluation could cause health risks because it can ameliorate and mask digestive symptoms of celiac disease, delaying or avoiding its correct diagnosis and therapy. | 2 | Carbohydrates |
Ultraviolet helps detect organic material deposits that remain on surfaces where periodic cleaning and sanitizing may have failed. It is used in the hotel industry, manufacturing, and other industries where levels of cleanliness or contamination are inspected.
Perennial news features for many television news organizations involve an investigative reporter using a similar device to reveal unsanitary conditions in hotels, public toilets, hand rails, and such. | 4 | Ultraviolet Radiation |
The variables and design considerations for strippers are many. Among them are the entering conditions, the degree of recovery of the solute needed, the choice of the stripping agent and its flow, the operating conditions, the number of stages, the heat effects, and the type and size of the equipment.
The degree of recovery is often determined by environmental regulations, such as for volatile organic compounds like chloroform.
Frequently, steam, air, inert gases, and hydrocarbon gases are used as stripping agents. This is based on solubility, stability, degree of corrosiveness, cost, and availability. As stripping agents are gases, operation at nearly the highest temperature and lowest pressure that will maintain the components and not vaporize the liquid feed stream is desired. This allows for the minimization of flow. As with all other variables, minimizing cost while achieving efficient separation is the ultimate goal.
The size of the equipment, and particularly the height and diameter, is important in determining the possibility of flow channeling that would reduce the contact area between the liquid and vapor streams. If flow channeling is suspected to be occurring, a redistribution plate is often necessary to, as the name indicates, redistribute the liquid flow evenly to reestablish a higher contact area.
As mentioned previously, strippers can be trayed or packed. Packed columns, and particularly when random packing is used, are usually favored for smaller columns with a diameter less than 2 feet and a packed height of not more than 20 feet. Packed columns can also be advantageous for corrosive fluids, high foaming fluids, when fluid velocity is high, and when particularly low pressure drop is desired. Trayed strippers are advantageous because of ease of design and scale up. Structured packing can be used similar to trays despite possibly being the same material as dumped (random) packing. Using structured packing is a common method to increase the capacity for separation or to replace damaged trays.
Trayed strippers can have sieve, valve, or bubble cap trays while packed strippers can have either structured packing or random packing. Trays and packing are used to increase the contact area over which mass transfer can occur as mass transfer theory dictates. Packing can have varying material, surface area, flow area, and associated pressure drop. Older generation packing include ceramic Raschig rings and Berl saddles. More common packing materials are metal and plastic Pall rings, metal and plastic Zbigniew Białecki rings, and ceramic Intalox saddles. Each packing material of this newer generation improves the surface area, the flow area, and/or the associated pressure drop across the packing. Also important, is the ability of the packing material to not stack on top of itself. If such stacking occurs, it drastically reduces the surface area of the material. Lattice design work has been increasing of late that will further improve these characteristics.
During operation, monitoring the pressure drop across the column can help to determine the performance of the stripper. A changed pressure drop over a significant range of time can be an indication that the packing may need to be replaced or cleaned. | 1 | Separation Processes |
Some alternatives to IVF are:
*Artificial insemination, including intracervical insemination and intrauterine insemination of semen. It requires that a woman ovulates, but is a relatively simple procedure, and can be used in the home for self-insemination without medical practitioner assistance. The beneficiaries of artificial insemination are people who desire to give birth to their own child who may be single, people who are in a lesbian relationship or females who are in a heterosexual relationship but with a male partner who is infertile or who has a physical impairment which prevents full intercourse from taking place.
*Ovulation induction (in the sense of medical treatment aiming for the development of one or two ovulatory follicles) is an alternative for people with anovulation or oligoovulation, since it is less expensive and more easy to control. It generally involves antiestrogens such as clomifene citrate or letrozole, and is followed by natural or artificial insemination.
*Surrogacy, the process in which a surrogate agrees to bear a child for another person or persons, who will become the child's parent(s) after birth. People may seek a surrogacy arrangement when pregnancy is medically impossible, when pregnancy risks are too dangerous for the intended gestational carrier, or when a single man or a male couple wish to have a child.
*Adoption whereby a person assumes the parenting of another, usually a child, from that person's biological or legal parent or parents. | 0 | Cryobiology |
Gregory M. Fahy is a California-based cryobiologist, biogerontologist, and businessman. He is Vice President and Chief Scientific Officer at Twenty-First Century Medicine, Inc, and has co-founded Intervene Immune, a company developing clinical methods to reverse immune system aging. He is the 2022–2023 president of the Society for Cryobiology. | 0 | Cryobiology |
An ova bank, or cryobank, or egg cell bank is a facility that collects and stores human ova, mainly from ova donors, primarily for the purpose of achieving pregnancies of either the donor, at a later time (i.e. to overcome issues of infertility), or through third party reproduction, notably by artificial insemination. Ova donated in this way are known as donor ova. | 0 | Cryobiology |
Biomolecules are often purified via solvent gradient batch chromatography. Here smooth linear solvent gradients are applied to carefully handle the separation between the desired component and hundreds of impurities. The desired product is usually intermediate between weakly and strongly absorbing impurities. A center cut is required to get the desired pure product. Often the preparative resins have a low efficiency due to strong axial dispersion and slow mass transfer. Then a purification in one chromatographic step is not possible. Countercurrent movement as known from the SMB process would be required. For large scale productions and for very valuable molecules countercurrent solid movement need to be applied to increase the separation efficiency, the yield and the productivity of the purification. The MCSGP process combines both techniques in one process, the countercurrent SMB principle and the solvent gradient batch technique.
Discontinuous mode consists of equilibration, loading, washing, purification and regeneration steps. The discontinuous mode of operation allows exploiting the advantage of solvent gradients, but it implies high solvent consumptions and low productivities with respect to continuous countercurrent processes. An established process of this kind is the simulated moving bed technique (SMB) that requires the solvent-consuming steps of equilibration, washing, regeneration only once per operation and has a better resin utilization. However, major drawbacks of SMB are the inability of separating a mixture into three fractions and the lack of solvent gradient applicability.
In the case of antibodies, the state-of-the-art technique is based on batch affinity chromatography (with Protein A or Protein G as ligands) which is able to selectively bind antibody molecules. In general, affinity techniques have the advantage of purifying biomolecules with high yields and purities but the disadvantages are in general the high stationary phase cost, ligand leaching and reduced cleanability.
The MCSGP process can result in purities and yields comparable to those of purification using Protein A. The second application example for the MCSGP prototype is the separation of three MAb variants using a preparative weak cation-exchange resin. Although the intermediately eluting MAb variant can only be obtained with 80% purity at recoveries close to zero in a batch chromatographic process, the MCSGP process can provide 90% purity at 93% yield. A numerical comparison of the MCSGP process with the batch chromatographic process, and a batch chromatographic process including ideal recycling, has been performed using an industrial polypeptide purification as the model system. It shows that the MCSGP process can increase the productivity by a factor of 10 and reduce the solvent requirement by 90%.
The main advantages with respect to solvent gradient batch chromatography are high yields also for difficult separations, less solvent consumption, higher productivity, usage of countercurrent solid movement, which increases the separation efficiency. The process is continuous. Once a steady state is reached, it delivers continuously purified product in constant quality and quantity. Automatic cleaning in place is integrated. A pure empirical design of the operating conditions from a single solvent gradient batch chromatogram is possible. | 1 | Separation Processes |
IVF success rates are the percentage of all IVF procedures that result in favourable outcomes. Depending on the type of calculation used, this outcome may represent the number of confirmed pregnancies, called the pregnancy rate, or the number of live births, called the live birth rate. Due to advances in reproductive technology, live birth rates by cycle five of IVF have increased from 76% in 2005 to 80% in 2010, despite a reduction in the number of embryos being transferred (which decreased the multiple birth rate from 25% to 8%).
The success rate depends on variable factors such as age of the birthing person, cause of infertility, embryo status, reproductive history, and lifestyle factors. Younger candidates of IVF are more likely to get pregnant. People older than 41 are more likely to get pregnant with a donor egg. People who have been previously pregnant are in many cases more successful with IVF treatments than those who have never been pregnant. | 0 | Cryobiology |