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PUVA (psoralen and UVA) is an ultraviolet light therapy treatment for skin diseases: vitiligo, eczema, psoriasis, graft-versus-host disease, mycosis fungoides, large plaque parapsoriasis, and cutaneous T-cell lymphoma, using the sensitizing effects of the drug psoralen. The psoralen is applied or taken orally to sensitize the skin, then the skin is exposed to UVA.
Photodynamic therapy is the general use of nontoxic light-sensitive compounds that are exposed selectively to light, whereupon they become toxic to targeted malignant and other diseased cells. Still, PUVA therapy is often classified as a separate technique from photodynamic therapy. | 4 | Ultraviolet Radiation |
*Stefan Lovgren, [https://web.archive.org/web/20050319053238/http://news.nationalgeographic.com/news/2005/03/0318_050318_cryonics.html "Corpses Frozen for Future Rebirth by Arizona Company"], March 2005, National Geographic | 0 | Cryobiology |
Captive populations are subject to problems such as inbreeding depression, loss of genetic diversity and adaptations to captivity. It is important to manage captive populations in a way that minimizes these issues so that the individuals to be introduced will resemble the original founders as closely as possible, which will increase the chances of successful reintroductions. During the initial growth phase, the population size is rapidly expanded until a target population size is reached. The target population size is the number of individuals that are required to maintain appropriate levels of genetic diversity, which is generally considered to be 90% of the current genetic diversity after 100 years. The number of individuals required to meet this goal varies based on potential growth rate, effective size, current genetic diversity, and generation time. Once the target population size is reached, the focus shifts to maintaining the population and avoiding genetic issues within the captive population. | 0 | Cryobiology |
The basis of many functional gastrointestinal disorders (FGIDs) is distension of the intestinal lumen. Such luminal distension may induce pain, a sensation of bloating, abdominal distension and motility disorders. Therapeutic approaches seek to reduce factors that lead to distension, particularly of the distal small and proximal large intestine. Food substances that can induce distension are those that are poorly absorbed in the proximal small intestine, osmotically active, and fermented by intestinal bacteria with hydrogen (as opposed to methane) production. The small molecule FODMAPs exhibit these characteristics.
Over many years, there have been multiple observations that ingestion of certain short-chain carbohydrates, including lactose, fructose and sorbitol, fructans and galactooligosaccharides, can induce gastrointestinal discomfort similar to that of people with irritable bowel syndrome. These studies also showed that dietary restriction of short-chain carbohydrates was associated with symptoms improvement.
These short-chain carbohydrates (lactose, fructose and sorbitol, fructans and GOS) behave similarly in the intestine. Firstly, being small molecules and either poorly absorbed or not absorbed at all, they drag water into the intestine via osmosis. Secondly, these molecules are readily fermented by colonic bacteria, so upon malabsorption in the small intestine they enter the large intestine where they generate gases (hydrogen, carbon dioxide and methane). The dual actions of these carbohydrates cause an expansion in volume of intestinal contents, which stretches the intestinal wall and stimulates nerves in the gut. It is this stretching that triggers the sensations of pain and discomfort that are commonly experienced by people with IBS.
The FODMAP concept was first published in 2005 as part of a hypothesis paper. In this paper, it was proposed that a collective reduction in the dietary intake of all indigestible or slowly absorbed, short-chain carbohydrates would minimise stretching of the intestinal wall. This was proposed to reduce stimulation of the guts nervous system and provide the best chance of reducing symptom generation in people with IBS (see below). At the time, there was no collective term for indigestible or slowly absorbed, short-chain carbohydrates, so the term FODMAP' was created to improve understanding and facilitate communication of the concept.
The low FODMAP diet was originally developed by a research team at Monash University in Melbourne, Australia. The Monash team undertook the first research to investigate whether a low FODMAP diet improved symptom control in patients with IBS and established the mechanism by which the diet exerted its effect. Monash University also established a rigorous food analysis program to measure the FODMAP content of a wide selection of Australian and international foods. The FODMAP composition data generated by Monash University updated previous data that was based on limited literature, with guesses (sometimes wrong) made where there was little information. | 2 | Carbohydrates |
Di(2-ethylhexyl)phosphoric acid (DEHPA or HDEHP) is an organophosphorus compound with the formula (CHO)POH. The colorless liquid is a diester of phosphoric acid and 2-ethylhexanol. It is used in the solvent extraction of uranium, vanadium and the rare-earth metals. | 1 | Separation Processes |
Ultraviolet in sewage treatment is commonly replacing chlorination. This is in large part because of concerns that reaction of the chlorine with organic compounds in the waste water stream could synthesize potentially toxic and long lasting chlorinated organics and also because of the environmental risks of storing chlorine gas or chlorine containing chemicals. Individual wastestreams to be treated by UVGI must be tested to ensure that the method will be effective due to potential interferences such as suspended solids, dyes, or other substances that may block or absorb the UV radiation. According to the World Health Organization, "UV units to treat small batches (1 to several liters) or low flows (1 to several liters per minute) of water at the community level are estimated to have costs of US$20 per megaliter, including the cost of electricity and consumables and the annualized capital cost of the unit."
Large-scale urban UV wastewater treatment is performed in cities such as Edmonton, Alberta. The use of ultraviolet light has now become standard practice in most municipal wastewater treatment processes. Effluent is now starting to be recognized as a valuable resource, not a problem that needs to be dumped. Many wastewater facilities are being renamed as water reclamation facilities, whether the wastewater is discharged into a river, used to irrigate crops, or injected into an aquifer for later recovery. Ultraviolet light is now being used to ensure water is free from harmful organisms. | 4 | Ultraviolet Radiation |
Hysteresis in cell biology often follows bistable systems where the same input state can lead to two different, stable outputs. Where bistability can lead to digital, switch-like outputs from the continuous inputs of chemical concentrations and activities, hysteresis makes these systems more resistant to noise. These systems are often characterized by higher values of the input required to switch into a particular state as compared to the input required to stay in the state, allowing for a transition that is not continuously reversible, and thus less susceptible to noise.
Cells undergoing cell division exhibit hysteresis in that it takes a higher concentration of cyclins to switch them from G2 phase into mitosis than to stay in mitosis once begun.
Biochemical systems can also show hysteresis-like output when slowly varying states that are not directly monitored are involved, as in the case of the cell cycle arrest in yeast exposed to mating pheromone. Here, the duration of cell cycle arrest depends not only on the final level of input Fus3, but also on the previously achieved Fus3 levels. This effect is achieved due to the slower time scales involved in the transcription of intermediate Far1, such that the total Far1 activity reaches its equilibrium value slowly, and for transient changes in Fus3 concentration, the response of the system depends on the Far1 concentration achieved with the transient value. Experiments in this type of hysteresis benefit from the ability to change the concentration of the inputs with time. The mechanisms are often elucidated by allowing independent control of the concentration of the key intermediate, for instance, by using an inducible promoter.
Darlington in his classic works on genetics discussed hysteresis of the chromosomes, by which he meant "failure of the external form of the chromosomes to respond immediately to the internal stresses due to changes in their molecular spiral", as they lie in a somewhat rigid medium in the limited space of the cell nucleus.
In developmental biology, cell type diversity is regulated by long range-acting signaling molecules called morphogens that pattern uniform pools of cells in a concentration- and time-dependent manner. The morphogen sonic hedgehog (Shh), for example, acts on limb bud and neural progenitors to induce expression of a set of homeodomain-containing transcription factors to subdivide these tissues into distinct domains. It has been shown that these tissues have a memory of previous exposure to Shh.
In neural tissue, this hysteresis is regulated by a homeodomain (HD) feedback circuit that amplifies Shh signaling. In this circuit, expression of Gli transcription factors, the executors of the Shh pathway, is suppressed. Glis are processed to repressor forms (GliR) in the absence of Shh, but in the presence of Shh, a proportion of Glis are maintained as full-length proteins allowed to translocate to the nucleus, where they act as activators (GliA) of transcription. By reducing Gli expression then, the HD transcription factors reduce the total amount of Gli (GliT), so a higher proportion of GliT can be stabilized as GliA for the same concentration of Shh. | 3 | Magnetic Ordering |
Lactulose is used in the treatment of chronic constipation in patients of all ages as a long-term treatment. The dosage of lactulose for chronic idiopathic constipation is adjusted depending on the constipation severity and desired effect, from a mild stool softener to causing diarrhea. Lactulose is contraindicated in case of galactosemia, as most preparations contain the monosaccharide galactose due to its synthesis process.
Lactulose may be used to counter the constipating effects of opioids, and in the symptomatic treatment of hemorrhoids as a stool softener.
Lactulose is commonly prescribed for children who develop fear of their bowel movements and are withholders. This is because lactulose, when dosed in the proper amount, causes a bowel movement that is impossible to retain for very long. Lactulose is also used for the elderly because of its gentle and consistent results. | 2 | Carbohydrates |
Post-treatment disinfection provides secondary protection against compromised membranes and downstream problems. Disinfection by means of ultraviolet (UV) lamps (sometimes called germicidal or bactericidal) may be employed to sterilize pathogens that evade the RO process. Chlorination or chloramination (chlorine and ammonia) protects against pathogens that may have lodged in the distribution system downstream. | 1 | Separation Processes |
The vacuum ultraviolet (V‑UV) band (100–200 nm) can be generated by non-linear 4 wave mixing in gases by sum or difference frequency mixing of 2 or more longer wavelength lasers. The generation is generally done in gasses (e.g. krypton, hydrogen which are two-photon resonant near 193 nm) or metal vapors (e.g. magnesium). By making one of the lasers tunable, the V‑UV can be tuned. If one of the lasers is resonant with a transition in the gas or vapor then the V‑UV production is intensified. However, resonances also generate wavelength dispersion, and thus the phase matching can limit the tunable range of the 4 wave mixing. Difference frequency mixing (i.e., ) has an advantage over sum frequency mixing because the phase matching can provide greater tuning.
In particular, difference frequency mixing two photons of an (193 nm) excimer laser with a tunable visible or near IR laser in hydrogen or krypton provides resonantly enhanced tunable V‑UV covering from 100 nm to 200 nm. Practically, the lack of suitable gas / vapor cell window materials above the lithium fluoride cut-off wavelength limit the tuning range to longer than about 110 nm. Tunable V‑UV wavelengths down to 75 nm was achieved using window-free configurations. | 4 | Ultraviolet Radiation |
Glucose, along with fructose, is one of the primary sugars found in wine grapes. In wine, glucose tastes less sweet than fructose. It is a six-carbon sugar molecule derived from the breakdown of sucrose. At the beginning of the ripening stage there is usually more glucose than fructose present in the grape (as much as five times more) but the rapid development of fructose shifts the ratio to where at harvest there are generally equal amounts. Grapes that are overripe, such as some late harvest wines, may have more fructose than glucose. During fermentation, yeast cells break down and convert glucose first. The linking of glucose molecules with aglycone, in a process that creates glycosides, also plays a role in the resulting flavor of the wine due to their relation and interactions with phenolic compounds like anthocyanins and terpenoids. | 2 | Carbohydrates |
Signs and symptoms vary depending on the degree of hypothermia, and may be divided by the three stages of severity. People with hypothermia may appear pale and feel cold to touch.
Infants with hypothermia may feel cold when touched, with bright red skin and an unusual lack of energy.
Behavioural changes such as impaired judgement, impaired sense of time and place, unusual aggression and numbness can be observed in individuals with hypothermia, they can also deny their condition and refuse any help. A hypothermic person can be euphoric and hallucinating.
Cold stress refers to a near-normal body temperature with low skin temperature, signs include shivering. Cold stress is caused by cold exposure and it can lead to hypothermia and frostbite if not treated. | 0 | Cryobiology |
Recent advances in technology have allowed for the use of argon gas to drive ice formation using a principle known as the Joule-Thomson effect. This gives physicians excellent control of the ice and minimizes complications using ultra-thin 17 gauge cryoneedles. | 0 | Cryobiology |
21st Century Medicine (21CM) is a California cryobiological research company which has as its primary focus the development of perfusates and protocols for viable long-term cryopreservation of human organs, tissues and cells at temperatures below −100 °C through the use of vitrification. 21CM was founded in 1993.
In 2004 21CM received a $900,000 grant from the U.S. National Institutes of Health (NIH) to study a preservation solution developed by the University of Rochester in New York for extending simple cold storage time of human hearts removed for transplant.
At the July 2005 annual conference of the Society for Cryobiology, 21st Century Medicine announced the vitrification of a rabbit kidney to −135 °C with their vitrification mixture. The kidney was successfully transplanted upon rewarming to a rabbit, the rabbit being euthanized on the 48th day for histological follow-up.
On February 9, 2016, 21st Century Medicine won the Small Mammal Brain Preservation Prize. On March 13, 2018, they won the Large Mammal Brain Preservation Prize. | 0 | Cryobiology |
* The rotary vacuum drum filter is a continuous and automatic operation, so the operating cost is low.
* The variation of the drum speed rotating can be used to control the cake thickness.
* The process can be easily modified (pre-coating filter process).
* Can produce relatively clean product by adding a showering device. | 1 | Separation Processes |
Drug delivery refers to technology used to present a drug to a pre-determined region of the body for drug emission and absorption. Principles relating to route of administration, metabolism, site of specific targeting, and toxicity are most important within this field. Drugs administered orally (through mouth) are usually encapsulated in some structure in order to protect the drug from immune and biological responses. These structures aim to keep the drug intact until its site of action and release it at a correct dosage when exposed to a specific marker. Corn and potato starch are often used for this as they contain 60-80% amylopectin. They are mostly used in solid preparations: powders, granules, capsules, and tablets. As a natural polysaccharide, it has a compatible nature with anatomical structures and molecules. This prevents any sort of negative immune response, which is a highly controversial topic in drug delivery. Biodegradability of starch allows it to keep the drug intact until reaching its site of action. This allows the drug to avoid low pH situations such as the digestive system. Native starch can also be modified in physical, chemical, and enzymatic ways to improve mechanical or biochemical properties. Within drug delivery, physical modification include treatment under mechanical forces, heat, or pressure. Chemical modifications attempt to alter molecular structure which can include breaking or addition of bonds. Treating starch with enzymes can allow for increased water solubility. | 2 | Carbohydrates |
* Due to the structure, the pressure difference is theoretically limited to atmospheric pressure (1 bar), and in practice somewhat lower.
* Besides the drum, other accessories, for example, agitators and vacuum pump, vacuum receivers, slurry pumps are required.
* The discharge cake contains residual moisture.
* The cake tends to crack due to their air drawn through by the vacuum system, so that washing and drying are not efficient.
* High energy consumption by the vacuum pump. | 1 | Separation Processes |
Growing crystals for X-ray crystallography can be quite difficult. For X-ray analysis, single perfect crystals are required. Typically a small amount (5–100 mg) of a pure compound is used, and crystals are allowed to grow very slowly. Several techniques can be used to grow these perfect crystals:
* Slow evaporation of a single solvent - typically the compound is dissolved in a suitable solvent and the solvent is allowed to slowly evaporate. Once the solution is saturated crystals can be formed.
* Slow evaporation of a multi-solvent system - the same as above, however as the solvent composition changes due to evaporation of the more volatile solvent. The compound is more soluble in the volatile solvent, and so the compound becomes increasingly insoluble in solution and crystallizes.
* Slow diffusion - similar to the above. However, a second solvent is allowed to evaporate from one container into a container holding the compound solution (gas diffusion). As the solvent composition changes due to an increase in the solvent that has gas diffused into the solution, the compound becomes increasingly insoluble in the solution and crystallizes.
* Interface/slow mixing (often performed in an NMR tube). Similar to the above, but instead of one solvent gas-diffusing into another, the two solvents mix (diffuse) by liquid-liquid diffusion. Typically a second solvent is "layered" carefully on top of the solution containing the compound. Over time the two solution mix. As the solvent composition changes due to diffusion, the compound becomes increasingly insoluble in solution and crystallizes, usually at the interface. Additionally, it is better to use a denser solvent as the lower layer, and/or a hotter solvent as the upper layer because this results in the slower mixing of the solvents.
* Specialized equipment can be used in the shape of an "H" to perform the above, where one of the vertical lines of the "H" is a tube containing a solution of the compound, and the other vertical line of the "H" is a tube containing a solvent which the compound is not soluble in, and the horizontal line of the "H" is a tube which joins the two vertical tubes, which also has a fine glass sinter that restricts the mixing of the two solvents.
* Once single perfect crystals have been obtained, it is recommended that the crystals are kept in a sealed vessel with some of the liquid of crystallization to prevent the crystal from drying out. Single perfect crystals may contain solvent of crystallization in the crystal lattice. Loss of this internal solvent from the crystals can result in the crystal lattice breaking down, and the crystals turning to powder. | 1 | Separation Processes |
Bili light. A type of phototherapy that uses blue light with a range of 420–470 nm, used to treat neonatal jaundice. | 4 | Ultraviolet Radiation |
Somatic tissue can be stored in vitro for short periods of time. This is done in a light and temperature controlled environment that regulates the growth of cells. As an ex situ conservation technique tissue culture is primary used for clonal propagation of vegetative tissue or immature seeds. This allows for the proliferation of clonal plants from a relatively small amount of parent tissue. | 0 | Cryobiology |
Heat is primarily generated in muscle tissue, including the heart, and in the liver, while it is lost through the skin (90%) and lungs (10%). Heat production may be increased two- to four-fold through muscle contractions (i.e. exercise and shivering). The rate of heat loss is determined, as with any object, by convection, conduction, and radiation. The rates of these can be affected by body mass index, body surface area to volume ratios, clothing and other environmental conditions.
Many changes to physiology occur as body temperatures decrease. These occur in the cardiovascular system leading to the Osborn J wave and other dysrhythmias, decreased central nervous system electrical activity, cold diuresis, and non-cardiogenic pulmonary edema.
Research has shown that glomerular filtration rates (GFR) decrease as a result of hypothermia. In essence, hypothermia increases preglomerular vasoconstriction, thus decreasing both renal blood flow (RBF) and GFR. | 0 | Cryobiology |
The sample (fruits, vegetables, tobacco, etc.) is homogenized and centrifuged with a reagent and agitated for 1 minute. The reagents used depend on the type of sample to be analyzed. Following this, the sample is put through a dispersive solid phase extraction cleanup prior to analysis by gas-liquid chromatography or liquid-liquid chromatography.
Samples prepared using the QuEChERS method can be processed more quickly using a homogenization instrument. Such instruments can homogenize the food sample in a centrifuge tube, then agitate the sample with the reagent of choice, before moving the extracted sample for centrifuging. By using such an instrument, the samples can be moved through the QuEChERS method more quickly.
Some modifications to the original QuEChERS method had to be introduced to ensure efficient extraction of pH-dependent compounds (e.g., phenoxyalkanoic acids), to minimize degradation of susceptible compounds (e.g., base and acid labile pesticides) and to expand the spectrum of matrices covered. | 1 | Separation Processes |
In addition to unusual experimental properties, spin glasses are the subject of extensive theoretical and computational investigations. A substantial part of early theoretical work on spin glasses dealt with a form of mean-field theory based on a set of replicas of the partition function of the system.
An important, exactly solvable model of a spin glass was introduced by David Sherrington and Scott Kirkpatrick in 1975. It is an Ising model with long range frustrated ferro- as well as antiferromagnetic couplings. It corresponds to a mean-field approximation of spin glasses describing the slow dynamics of the magnetization and the complex non-ergodic equilibrium state.
Unlike the Edwards–Anderson (EA) model, in the system though only two-spin interactions are considered, the range of each interaction can be potentially infinite (of the order of the size of the lattice). Therefore, we see that any two spins can be linked with a ferromagnetic or an antiferromagnetic bond and the distribution of these is given exactly as in the case of Edwards–Anderson model. The Hamiltonian for SK model is very similar to the EA model:
where have same meanings as in the EA model. The equilibrium solution of the model, after some initial attempts by Sherrington, Kirkpatrick and others, was found by Giorgio Parisi in 1979 with the replica method. The subsequent work of interpretation of the Parisi solution—by M. Mezard, G. Parisi, M.A. Virasoro and many others—revealed the complex nature of a glassy low temperature phase characterized by ergodicity breaking, ultrametricity and non-selfaverageness. Further developments led to the creation of the cavity method, which allowed study of the low temperature phase without replicas. A rigorous proof of the Parisi solution has been provided in the work of Francesco Guerra and Michel Talagrand.
The formalism of replica mean-field theory has also been applied in the study of neural networks, where it has enabled calculations of properties such as the storage capacity of simple neural network architectures without requiring a training algorithm (such as backpropagation) to be designed or implemented.
More realistic spin glass models with short range frustrated interactions and disorder, like the Gaussian model where the couplings between neighboring spins follow a Gaussian distribution, have been studied extensively as well, especially using Monte Carlo simulations. These models display spin glass phases bordered by sharp phase transitions.
Besides its relevance in condensed matter physics, spin glass theory has acquired a strongly interdisciplinary character, with applications to neural network theory, computer science, theoretical biology, econophysics etc. | 3 | Magnetic Ordering |
Most tanning beds are horizontal enclosures with a bench and canopy (lid) that house long, low-pressure fluorescent bulbs (100–200 watt) under an acrylic surface. The tanner is surrounded by bulbs when the canopy is closed. Modern tanning beds emit mostly UVA (the sun emits around 95% UVA and 5% UVB). One review of studies found that the UVB irradiance of beds was on average lower than the summer sun at latitudes 37°S to 35°N, but that UVA irradiance was on average much higher.
The user sets a timer (or it is set remotely by the salon operator), lies on the bed and pulls down the canopy. The maximum exposure time for most low-pressure beds is 15–20 minutes. In the US, maximum times are set by the manufacturer according to how long it takes to produce four "minimal erythema doses" (MEDs), an upper limit laid down by the FDA. An MED is the amount of UV radiation that will produce erythema (redness of the skin) within a few hours of exposure.
High-pressure beds use smaller, higher-wattage quartz bulbs and emit a higher percentage of UVA. They may emit 10–15 times more UVA than the midday sun, and have a shorter maximum exposure time (typically 10–12 minutes). UVA gives an immediate, short-term tan by bronzing melanin in the skin, but no new melanin is formed. UVB has no immediate bronzing effect, but with a delay of 72 hours makes the skin produce new melanin, leading to tans of longer duration. UVA is less likely to cause burning or dry skin than UVB, but is associated with wrinkling and loss of elasticity because it penetrates deeper.
Commercial tanning beds cost $6,000 to $30,000 as of 2006, with high-pressure beds at the high end. One Manhattan chain was charging $10 to $35 per session in 2016, depending on the number, strength, and type of bulbs. This is known as level 1–6 tanning; level 1 involves a basic low-pressure bed with 36 x 100-watt bulbs. Depending on the quality of the bed, it may contain a separate facial tanner, shoulder tanners, a choice of tanning levels and UVA/UVB combinations, sound system, MP3 connection, aromatherapy, air conditioning, a misting option and voice guide. There are also open-air beds, in which the tanner is not entirely enclosed. | 4 | Ultraviolet Radiation |
Established in 1972, the focus of the research is on cryoinjury, cryosurgery, cryopreservation, lyophilization and hypothermia. Since 1985 the Institute has published the open access peer-reviewed scientific journal Problems of Cryobiology and Cryomedicine. | 0 | Cryobiology |
Cryoablation of tumor induces necrosis of tumor cells. The immunotherapeutic effect of cryoablation of tumor is the result of the release of intracellular tumor antigens from within the necrotized tumor cells. The released tumor antigens help activate anti-tumor T cells, which destroy remaining malignant cells. Thus, cryoablation of tumor elicits a systemic anti-tumor immunologic response.
The resulting immunostimulation from cryoablation may not be sufficient to induce sustained, systemic regression of metastases, and can be synergised with the combination of immunotherapy treatment and vaccine adjuvants.
Various adjuvant immunotherapy and chemotherapy treatments can be combined with cryoablation to sustain systemic anti-tumor response with regression of metastases, including:
* Injection of immunomodulating drugs (i.e.: therapeutic antibodies) and vaccine adjuvants (saponins) directly into the cryoablated, necrotized tumor lysate, immediately after cryoablation
* Administration of autologous immune enhancement therapy, including: dendritic cell therapy, CIK cell therapy | 0 | Cryobiology |
Cold hardening is the physiological and biochemical process by which an organism prepares for cold weather. | 0 | Cryobiology |
More than one kind of crystal system has a single axis of high symmetry (threefold, fourfold or sixfold). The anisotropy of such crystals is called uniaxial anisotropy. If the axis is taken to be the main symmetry axis of the crystal, the lowest order term in the energy is
The ratio is an energy density (energy per unit volume). This can also be represented in spherical polar coordinates with , , and :
The parameter , often represented as , has units of energy density and depends on composition and temperature.
The minima in this energy with respect to satisfy
If ,
the directions of lowest energy are the directions. The axis is called the easy axis. If , there is an easy plane perpendicular to the symmetry axis (the basal plane of the crystal).
Many models of magnetization represent the anisotropy as uniaxial and ignore higher order terms. However, if , the lowest energy term does not determine the direction of the easy axes within the basal plane. For this, higher-order terms are needed, and these depend on the crystal system (hexagonal, tetragonal or rhombohedral). | 3 | Magnetic Ordering |
Rewarming can be done with a number of methods including passive external rewarming, active external rewarming, and active internal rewarming. Passive external rewarming involves the use of a person's own ability to generate heat by providing properly insulated dry clothing and moving to a warm environment. Passive external rewarming is recommended for those with mild hypothermia.
Active external rewarming involves applying warming devices externally, such as a heating blanket. These may function by warmed forced air (Bair Hugger is a commonly used device), chemical reactions, or electricity. In wilderness environments, hypothermia may be helped by placing hot water bottles in both armpits and in the groin. Active external rewarming is recommended for moderate hypothermia. Active core rewarming involves the use of intravenous warmed fluids, irrigation of body cavities with warmed fluids (the chest or abdomen), use of warm humidified inhaled air, or use of extracorporeal rewarming such as via a heart lung machine or extracorporeal membrane oxygenation (ECMO). Extracorporeal rewarming is the fastest method for those with severe hypothermia. When severe hypothermia has led to cardiac arrest, effective extracorporeal warming results in survival with normal mental function about 50% of the time. Chest irrigation is recommended if bypass or ECMO is not possible.
Rewarming shock (or rewarming collapse) is a sudden drop in blood pressure in combination with a low cardiac output which may occur during active treatment of a severely hypothermic person. There was a theoretical concern that external rewarming rather than internal rewarming may increase the risk. These concerns were partly believed to be due to afterdrop, a situation detected during laboratory experiments where there is a continued decrease in core temperature after rewarming has been started. Recent studies have not supported these concerns, and problems are not found with active external rewarming. | 0 | Cryobiology |
An electrostatic separator is a device for separating particles by mass in a low energy charged beam.
An example is the electrostatic precipitator used in coal-fired power plants to treat exhaust gas, removing small particles that cause air pollution.
Electrostatic separation is a process that uses electrostatic charges to separate crushed particles of material. An industrial process used to separate large amounts of material particles, electrostatic separating is most often used in the process of sorting mineral ore. This process can help remove valuable material from ore, or it can help remove foreign material to purify a substance. In mining, the process of crushing mining ore into particles for the purpose of separating minerals is called beneficiation.
Generally, electrostatic charges are used to attract or repel differently charged material. When electrostatic separation uses the force of attraction to sort particles, conducting particles stick to an oppositely charged object, such as a metal drum, thereby separating them from the particle mixture. When this type of beneficiation uses repelling force, it is normally employed to change the trajectory of falling objects to sort them into different places. This way, when a mixture of particles falls past a repelling object, the particles with the correct charge fall away from the other particles when they are repelled by the similarly charged object.
An electric charge can be positive or negative — objects with a positive charge repel other positively charged objects, thereby causing them to push away from each other, while a positively charged object would attract to a negatively charged object, thereby causing the two to draw together.
Experiments showing electrostatic sorting in action can help make the process more clear. To exhibit electrostatic separation at home, an experiment can be conducted using peanuts that are still in their shells. When the shells are rubbed off of the peanuts and gently smashed into pieces, an electrostatically charged device, like a comb rubbed quickly against a wool sweater, will pick up the peanut shells with static electricity. The lightweight crushed shells that are oppositely charged from the comb easily move away from the edible peanut parts when the comb is passed nearby.
The electrostatic separation of conductors is one method of beneficiation; another common beneficiation method is magnetic beneficiation. Electrostatic separation is a preferred sorting method when dealing with separating conductors from electrostatic separation non-conductors. In a similar way to that in which electrostatic separation sorts particles with different electrostatic charges magnetic beneficiation sorts particles that respond to a magnetic field. Electrostatic beneficiation is effective for removing particulate matter, such as ash from mined coal, while magnetic separation functions well for removing the magnetic iron ore from deposits of clay in the earth. | 1 | Separation Processes |
Black light is commonly used to authenticate oil paintings, antiques and banknotes. Black lights can be used to differentiate real currency from counterfeit notes because, in many countries, legal banknotes have fluorescent symbols on them that only show under a black light. In addition, the paper used for printing money does not contain any of the brightening agents which cause commercially available papers to fluoresce under black light. Both of these features make illegal notes easier to detect and more difficult to successfully counterfeit. The same security features can be applied to identification cards such as passports or driver's licenses.
Other security applications include the use of pens containing a fluorescent ink, generally with a soft tip, that can be used to "invisibly" mark items. If the objects that are so marked are subsequently stolen, a black light can be used to search for these security markings. At some amusement parks, nightclubs and at other, day-long (or night-long) events, a fluorescent mark is rubber stamped onto the wrist of a guest who can then exercise the option of leaving and being able to return again without paying another admission fee. | 4 | Ultraviolet Radiation |