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The field of building-integrated photovoltaics (BIPV) has gained attention from the scientific community due to its potential to reduce pollution and materials and electricity costs, as well as to improve the aesthetics of a building. In recent years, scientists have looked at ways to incorporate DSSC’s in BIPV applications, since the dominant Si-based PV systems in the market have a limited presence in this field due to their energy-intensive manufacturing methods, poor conversion efficiency under low light intensities, and high maintenance requirements. In 2021, a group of researchers from the Silesian University of Technology in Poland developed a DSSC in which the classic glass counter electrode was replaced by an electrode based on a ceramic tile and nickel foil. The motivation for this change was that, despite that glass substrates have resulted in the highest recorded efficiencies for DSSC’s, for BIPV applications like roof tiles or building facades, lighter and more flexible materials are essential. This includes plastic films, metals, steel, or paper, which may also reduce manufacturing costs. The team found that the cell had an efficiency of 4% (close to that of a solar cell with a glass counter electrode), demonstrated the potential for creating building-integrated DSSC’s that are stable and low-cost. | 4 | Ultraviolet Radiation |
Vacuum ceramic filters are to be found in the following industries:
* paper making
* metallurgy
* water treatment
* chemical
* ore beneficiation process in mining (iron, gold, nickel, copper and quartz).
The process is used during a large continuous process of separating free filtering suspensions where washing is not required. Basically the filter works to separates solid-liquid mixtures by removing the water from mineral concentrates and moulding the feed slurries into pellets. This is accomplished by capillary action under low vacuum pressure. The pelletizing of the slurries is done by adding some solid matter to the sewage sludge so that water can be easily removed from the mixture. Eventually, the final cake products contain very little moisture and can be deposited as sewage. This process is commonly followed by bleaching and heating the cake. The end product of this filtration is a dry cake and filtrate containing no solid product. | 1 | Separation Processes |
When an external magnetic field is applied to a ferromagnetic material such as iron, the atomic domains align themselves with it. Even when the field is removed, part of the alignment will be retained: the material has become magnetized. Once magnetized, the magnet will stay magnetized indefinitely. To demagnetize it requires heat or a magnetic field in the opposite direction. This is the effect that provides the element of memory in a hard disk drive.
The relationship between field strength and magnetization is not linear in such materials. If a magnet is demagnetized () and the relationship between and is plotted for increasing levels of field strength, follows the initial magnetization curve. This curve increases rapidly at first and then approaches an asymptote called magnetic saturation. If the magnetic field is now reduced monotonically, follows a different curve. At zero field strength, the magnetization is offset from the origin by an amount called the remanence. If the relationship is plotted for all strengths of applied magnetic field the result is a hysteresis loop called the main loop. The width of the middle section is twice the coercivity of the material.
A closer look at a magnetization curve generally reveals a series of small, random jumps in magnetization called Barkhausen jumps. This effect is due to crystallographic defects such as dislocations.
Magnetic hysteresis loops are not exclusive to materials with ferromagnetic ordering. Other magnetic orderings, such as spin glass ordering, also exhibit this phenomenon. | 3 | Magnetic Ordering |
The majority of sperm donors who donate their sperm through a sperm bank receive some kind of payment, although this is rarely a significant amount. A review including 29 studies from nine countries came to the result that the amount of money actual donors received for their donation varied from $10 to €70 per donation or sample. The payments vary from the situation in the United Kingdom where donors are only entitled to their expenses in connection with the donation, to the situation with some US sperm banks where a donor receives a set fee for each donation plus an additional amount for each vial stored. At one prominent California sperm bank for example, TSBC, donors receive roughly $50 for each donation (ejaculation) which has acceptable motility/survival rates both at donation and at a test-thaw a couple of days later. Because of the requirement for the two-day celibacy period before donation, and geographical factors which usually require the donor to travel, it is not a viable way to earn a significant income—and is far less lucrative than selling human eggs. Some private donors may seek remuneration although others donate for altruistic reasons. According to the EU Tissue Directive donors in EU may only receive compensation, which is strictly limited to making good the expenses and inconveniences related to the donation. | 0 | Cryobiology |
Exposure limits for UV, particularly the germicidal UV-C range, have evolved over time due to scientific research and changing technology. The American Conference of Governmental Industrial Hygienists (ACGIH) and the International Commission on Non-Ionizing Radiation Protection (ICNIRP) have set exposure limits to safeguard against both immediate and long-term effects of UV exposure. These limits, also referred to as Threshold Limit Values (TLVs), form the basis for emission limits in product safety standards.
The UV-C photobiological spectral band is defined as 100–280 nm, with limits currently applying only from 180 to 280 nm. This reflects concerns about acute damage such as erythema and photokeratitis as well as long-term delayed effects like photocarcinogenesis. However, with the increased safety evidence surrounding UV-C for germicidal applications, the existing ACGIH TLVs were revised in 2022.
The TLVs for the 222 nm UV-C wavelength (peak emissions from KrCl excimer lamps), following the 2022 revision, are now 161 mJ/cm for eye exposure and 479 mJ/cm for skin exposure over an eight-hour period. For the 254 nm UV wavelength, the updated exposure limit is now set at 6 mJ/cm for eyes and 10 mJ/cm for skin. | 4 | Ultraviolet Radiation |
In a cubic crystal the lowest order terms in the energy are
If the second term can be neglected, the easy axes are the ⟨100⟩ axes (i.e., the , , and , directions) for and the ⟨111⟩ directions for (see images on right).
If is not assumed to be zero, the easy axes depend on both and . These are given in the table below, along with hard axes (directions of greatest energy) and intermediate axes (saddle points) in the energy). In energy surfaces like those on the right, the easy axes are analogous to valleys, the hard axes to peaks and the intermediate axes to mountain passes.
Below are some room-temperature anisotropy constants for cubic ferromagnets. The compounds involving are ferrites, an important class of ferromagnets. In general the anisotropy parameters for cubic ferromagnets are higher than those for uniaxial ferromagnets. This is consistent with the fact that the lowest order term in the expression for cubic anisotropy is fourth order, while that for uniaxial anisotropy is second order. | 3 | Magnetic Ordering |
The simplest way of understanding spin waves is to consider the Hamiltonian for the Heisenberg ferromagnet:
where is the exchange energy, the operators represent the spins at Bravais lattice points, is the Landé -factor, is the Bohr magneton and is the internal field which includes the external field plus any "molecular" field. Note that in the classical continuum case and in dimensions the Heisenberg ferromagnet equation has the form
In and dimensions this equation admits several integrable and non-integrable extensions like the Landau-Lifshitz equation, the Ishimori equation and so on. For a ferromagnet and the ground state of the Hamiltonian is that in which all spins are aligned parallel with the field . That is an eigenstate of can be verified by rewriting it in terms of the spin-raising and spin-lowering operators given by:
resulting in
where has been taken as the direction of the magnetic field. The spin-lowering operator annihilates the state with minimum projection of spin along the -axis, while the spin-raising operator annihilates the ground state with maximum spin projection along the -axis. Since
for the maximally aligned state, we find
where N is the total number of Bravais lattice sites. The proposition that the ground state is an eigenstate of the Hamiltonian is confirmed.
One might guess that the first excited state of the Hamiltonian has one randomly selected spin at position rotated so that
but in fact this arrangement of spins is not an eigenstate. The reason is that such a state is transformed by the spin raising and lowering operators. The operator will increase the -projection of the spin at position back to its low-energy orientation, but the operator will lower the -projection of the spin at position . The combined effect of the two operators is therefore to propagate the rotated spin to a new position, which is a hint that the correct eigenstate is a spin wave, namely a superposition of states with one reduced spin. The exchange energy penalty associated with changing the orientation of one spin is reduced by spreading the disturbance over a long wavelength. The degree of misorientation of any two near-neighbor spins is thereby minimized. From this explanation one can see why the Ising model magnet with discrete symmetry has no spin waves: the notion of spreading a disturbance in the spin lattice over a long wavelength makes no sense when spins have only two possible orientations. The existence of low-energy excitations is related to the fact that in the absence of an external field, the spin system has an infinite number of degenerate ground states with infinitesimally different spin orientations. The existence of these ground states can be seen from the fact that the state does not have the full rotational symmetry of the Hamiltonian , a phenomenon which is called spontaneous symmetry breaking. | 3 | Magnetic Ordering |
Using the addition theorem of tensor operators, the product of a rank n tensor and a rank m tensor can generate a new tensor with rank n+m ~ |n-m|. Therefore, a high rank tensor can be expressed as the product of low rank tensors. This convention is useful to interpret the high rank multipolar exchange terms as a "multi-exchange" process of dipoles (or pseudospins). For example, for the spherical harmonic tensor operators of case, we have
If so, a quadrupole-quadrupole interaction (see next section) can be considered as a two steps dipole-dipole interaction. For example, , so the one step quadrupole transition on site now becomes a two steps of dipole transition . Hence not only inter-site-exchange but also intra-site-exchange terms appear (so called multi-exchange). If is even larger, one can expect more complicated intra-site-exchange terms would appear. However, one has to note that it is not a perturbation expansion but just a mathematical technique. The high rank terms are not necessarily smaller than low rank terms. In many systems, high rank terms are more important than low rank terms. | 3 | Magnetic Ordering |
The ozone layer can be depleted by free radical catalysts, including nitric oxide (NO), nitrous oxide (NO), hydroxyl (OH), atomic chlorine (Cl), and atomic bromine (Br). While there are natural sources for all of these species, the concentrations of chlorine and bromine increased markedly in recent decades because of the release of large quantities of man-made organohalogen compounds, especially chlorofluorocarbons (CFCs) and bromofluorocarbons. These highly stable compounds are capable of surviving the rise to the stratosphere, where Cl and Br radicals are liberated by the action of ultraviolet light. Each radical is then free to initiate and catalyze a chain reaction capable of breaking down over 100,000 ozone molecules. By 2009, nitrous oxide was the largest ozone-depleting substance (ODS) emitted through human activities.
The breakdown of ozone in the stratosphere results in reduced absorption of ultraviolet radiation. Consequently, unabsorbed and dangerous ultraviolet radiation is able to reach the Earths surface at a higher intensity. Ozone levels have dropped by a worldwide average of about 4 percent since the late 1970s. For approximately 5 percent of the Earths surface, around the north and south poles, much larger seasonal declines have been seen, and are described as "ozone holes". "Ozone holes" are actually patches in the ozone layer in which the ozone is thinner. The thinnest parts of the ozone are at the polar points of Earths axis. The discovery of the annual depletion of ozone above the Antarctic was first announced by Joe Farman, Brian Gardiner and Jonathan Shanklin, in a paper which appeared in Nature' on May 16, 1985.
Regulation attempts have included but not have been limited to the Clean Air Act implemented by the United States Environmental Protection Agency. The Clean Air Act introduced the requirement of [https://www.epa.gov/criteria-air-pollutants/naaqs-table National Ambient Air Quality Standards (NAAQS)] with ozone pollutions being one of six criteria pollutants. This regulation has proven to be effective since counties, cities and tribal regions must abide by these standards and the EPA also provides assistance for each region to regulate contaminants. Effective presentation of information has also proven to be important in order to educate the general population of the existence and regulation of ozone depletion and contaminants. A scientific paper was written by Sheldon Ungar in which the author explores and studies how information about the depletion of the ozone, climate change and various related topics. The ozone case was communicated to lay persons "with easy-to-understand bridging metaphors derived from the popular culture" and related to "immediate risks with everyday relevance". The specific metaphors used in the discussion (ozone shield, ozone hole) proved quite useful and, compared to global climate change, the ozone case was much more seen as a "hot issue" and imminent risk. Lay people were cautious about a depletion of the ozone layer and the risks of skin cancer.
"Bad" ozone can cause adverse health risks respiratory effects (difficulty breathing) and is proven to be an aggravator of respiratory illnesses such as asthma, COPD and emphysema. That is why many countries have set in place regulations to improve "good" ozone and prevent the increase of "bad" ozone in urban or residential areas. In terms of ozone protection (the preservation of "good" ozone) the European Union has strict guidelines on what products are allowed to be bought, distributed or used in specific areas. With effective regulation, the ozone is expected to heal over time.
In 1978, the United States, Canada and Norway enacted bans on CFC-containing aerosol sprays that damage the ozone layer. The European Community rejected an analogous proposal to do the same. In the U.S., chlorofluorocarbons continued to be used in other applications, such as refrigeration and industrial cleaning, until after the discovery of the Antarctic ozone hole in 1985. After negotiation of an international treaty (the Montreal Protocol), CFC production was capped at 1986 levels with commitments to long-term reductions. This allowed for a ten-year phase-in for developing countries (identified in Article 5 of the protocol). Since that time, the treaty was amended to ban CFC production after 1995 in the developed countries, and later in developing countries. Today, all of the world's 197 countries have signed the treaty. Beginning January 1, 1996, only recycled and stockpiled CFCs were available for use in developed countries like the US. This production phaseout was possible because of efforts to ensure that there would be substitute chemicals and technologies for all ODS uses.
On August 2, 2003, scientists announced that the global depletion of the ozone layer may be slowing down because of the international regulation of ozone-depleting substances. In a study organized by the American Geophysical Union, three satellites and three ground stations confirmed that the upper-atmosphere ozone-depletion rate slowed significantly during the previous decade. Some breakdown can be expected to continue because of ODSs used by nations which have not banned them, and because of gases which are already in the stratosphere. Some ODSs, including CFCs, have very long atmospheric lifetimes, ranging from 50 to over 100 years. It has been estimated that the ozone layer will recover to 1980 levels near the middle of the 21st century. A gradual trend toward "healing" was reported in 2016.
Compounds containing C–H bonds (such as hydrochlorofluorocarbons, or HCFCs) have been designed to replace CFCs in certain applications. These replacement compounds are more reactive and less likely to survive long enough in the atmosphere to reach the stratosphere where they could affect the ozone layer. While being less damaging than CFCs, HCFCs can have a negative impact on the ozone layer, so they are also being phased out. These in turn are being replaced by hydrofluorocarbons (HFCs) and other compounds that do not destroy stratospheric ozone at all.
The residual effects of CFCs accumulating within the atmosphere lead to a concentration gradient between the atmosphere and the ocean. This organohalogen compound is able to dissolve into the ocean's surface waters and is able to act as a time-dependent tracer. This tracer helps scientists study ocean circulation by tracing biological, physical and chemical pathways. | 4 | Ultraviolet Radiation |
Freezing is a common method of food preservation that slows both food decay and the growth of micro-organisms. Besides the effect of lower temperatures on reaction rates, freezing makes water less available for bacteria growth. Freezing is one of the oldest and most widely used methods of food preservation; since as long ago as 1842, freezing has been used in an ice and salt brine. In freezing, flavours, smell and nutritional content generally remain unchanged. Freezing became commercially applicable after the advent (introduction) of mechanical refrigeration. Freezing has been successfully employed for long term preservation of many foods providing a significantly extended shelf-life. Freezing preservation is generally regarded as superior to canning and dehydration with respect to retention in sensory attributes and nutritive attributes. | 0 | Cryobiology |
In wine tasting, humans are least sensitive to the taste of sweetness (in contrast to sensitivity to bitterness or sourness) with the majority of the population being able to detect sugar or "sweetness" in wines between 1% and 2.5% residual sugar. Additionally, other components of wine such as acidity and tannins can mask the perception of sugar in the wine. | 2 | Carbohydrates |
A group of researchers at Georgia Tech made dye-sensitized solar cells with a higher effective surface area by wrapping the cells around a quartz optical fiber. The researchers removed the cladding from optical fibers, grew zinc oxide nanowires along the surface, treated them with dye molecules, surrounded the fibers by an electrolyte and a metal film that carries electrons off the fiber. The cells are six times more efficient than a zinc oxide cell with the same surface area. Photons bounce inside the fiber as they travel, so there are more chances to interact with the solar cell and produce more current. These devices only collect light at the tips, but future fiber cells could be made to absorb light along the entire length of the fiber, which would require a coating that is conductive as well as transparent. Max Shtein of the University of Michigan said a sun-tracking system would not be necessary for such cells, and would work on cloudy days when light is diffuse. | 4 | Ultraviolet Radiation |
Pretreatment is important when working nanofiltration membranes due to their spiral-wound design. The material is engineered to allow one-way flow. The design does not allow for backpulsing with water or air agitation to scour its surface and remove accumulated solids. Since material cannot be removed from the membrane surface, it is susceptible to fouling (loss of production capacity). Therefore, pretreatment is a necessity for any RO or nanofiltration system. Pretreatment has four major components:
* Screening solids: Solids must be removed and the water treated to prevent membrane fouling by particle or biological growth, and reduce the risk of damage to high-pressure components.
* Cartridge filtration: String-wound polypropylene filters are typically used to remove particles of 1–5 µm diameter.
* Dosing: Oxidizing biocides, such as chlorine, are added to kill bacteria, followed by bisulfite dosing to deactivate the chlorine that can destroy a thin-film composite membrane. Biofouling inhibitors do not kill bacteria, while preventing them from growing slime on the membrane surface and plant walls.
* Prefiltration pH adjustment: If the pH, hardness and the alkalinity in the feedwater result in scaling while concentrated in the reject stream, acid is dosed to maintain carbonates in their soluble carbonic acid form.
:CO + HO = HCO + HO
:HCO + HO = HCO + HO
* Carbonic acid cannot combine with calcium to form calcium carbonate scale. Calcium carbonate scaling tendency is estimated using the Langelier saturation index. Adding too much sulfuric acid to control carbonate scales may result in calcium sulfate, barium sulfate, or strontium sulfate scale formation on the membrane.
* Prefiltration antiscalants: Scale inhibitors (also known as antiscalants) prevent formation of more scales than acid, which can only prevent formation of calcium carbonate and calcium phosphate scales. In addition to inhibiting carbonate and phosphate scales, antiscalants inhibit sulfate and fluoride scales and disperse colloids and metal oxides. Despite claims that antiscalants can inhibit silica formation, no concrete evidence proves that silica polymerization is inhibited by antiscalants. Antiscalants can control acid-soluble scales at a fraction of the dosage required to control the same scale using sulfuric acid.
* Some small-scale desalination units use beach wells. These are usually drilled on the seashore. These intake facilities are relatively simple to build and the seawater they collect is pretreated via slow filtration through subsurface sand/seabed formations. Raw seawater collected using beach wells is often of better quality in terms of solids, silt, oil, grease, organic contamination, and microorganisms, compared to open seawater intakes. Beach intakes may also yield source water of lower salinity. | 1 | Separation Processes |
In condensed matter physics, magnetic anisotropy describes how an objects magnetic properties can be different depending on direction. In the simplest case, there is no preferential direction for an objects magnetic moment. It will respond to an applied magnetic field in the same way, regardless of which direction the field is applied. This is known as magnetic isotropy. In contrast, magnetically anisotropic materials will be easier or harder to magnetize depending on which way the object is rotated.
For most magnetically anisotropic materials, there are two easiest directions to magnetize the material, which are a 180° rotation apart. The line parallel to these directions is called the easy axis. In other words, the easy axis is an energetically favorable direction of spontaneous magnetization. Because the two opposite directions along an easy axis are usually equivalently easy to magnetize along, the actual direction of magnetization can just as easily settle into either direction, which is an example of spontaneous symmetry breaking.
Magnetic anisotropy is a prerequisite for hysteresis in ferromagnets: without it, a ferromagnet is superparamagnetic. | 3 | Magnetic Ordering |
In a traditional solid-state semiconductor, a solar cell is made from two doped crystals, one doped with n-type impurities (n-type semiconductor), which add additional free conduction band electrons, and the other doped with p-type impurities (p-type semiconductor), which add additional electron holes. When placed in contact, some of the electrons in the n-type portion flow into the p-type to "fill in" the missing electrons, also known as electron holes. Eventually enough electrons will flow across the boundary to equalize the Fermi levels of the two materials. The result is a region at the interface, the p–n junction, where charge carriers are depleted and/or accumulated on each side of the interface. In silicon, this transfer of electrons produces a potential barrier of about 0.6 to 0.7 eV.
When placed in the sun, photons of the sunlight can excite electrons on the p-type side of the semiconductor, a process known as photoexcitation. In silicon, sunlight can provide enough energy to push an electron out of the lower-energy valence band into the higher-energy conduction band. As the name implies, electrons in the conduction band are free to move about the silicon. When a load is placed across the cell as a whole, these electrons will flow out of the p-type side into the n-type side, lose energy while moving through the external circuit, and then flow back into the p-type material where they can once again re-combine with the valence-band hole they left behind. In this way, sunlight creates an electric current.
In any semiconductor, the band gap means that only photons with that amount of energy, or more, will contribute to producing a current. In the case of silicon, the majority of visible light from red to violet has sufficient energy to make this happen. Unfortunately higher energy photons, those at the blue and violet end of the spectrum, have more than enough energy to cross the band gap; although some of this extra energy is transferred into the electrons, the majority of it is wasted as heat. Another issue is that in order to have a reasonable chance of capturing a photon, the n-type layer has to be fairly thick. This also increases the chance that a freshly ejected electron will meet up with a previously created hole in the material before reaching the p–n junction. These effects produce an upper limit on the efficiency of silicon solar cells, currently around 20% for common modules and up to 27.1% for the best laboratory cells (33.16% is the theoretical maximum efficiency for single band gap solar cells, see Shockley–Queisser limit.).
By far the biggest problem with the conventional approach is cost; solar cells require a relatively thick layer of doped silicon in order to have reasonable photon capture rates, and silicon processing is expensive. There have been a number of different approaches to reduce this cost over the last decade, notably the thin-film approaches, but to date they have seen limited application due to a variety of practical problems. Another line of research has been to dramatically improve efficiency through the multi-junction approach, although these cells are very high cost and suitable only for large commercial deployments. In general terms the types of cells suitable for rooftop deployment have not changed significantly in efficiency, although costs have dropped somewhat due to increased supply. | 4 | Ultraviolet Radiation |
Some children conceived by IVF using anonymous donors report being troubled over not knowing about their donor parent as well any genetic relatives they may have and their family history.
Alana Stewart, who was conceived using donor sperm, began an online forum for donor children called AnonymousUS in 2010. The forum welcomes the viewpoints of anyone involved in the IVF process. Olivia Pratten, a donor-conceived Canadian, sued the province of British Columbia for access to records on her donor fathers identity in 2008. "Im not a treatment, Im a person, and those records belong to me," Pratten said. In May 2012, a court ruled in Prattens favour, agreeing that the laws at the time discriminated against donor children and making anonymous sperm and egg donation in British Columbia illegal.
In the U.K., Sweden, Norway, Germany, Italy, New Zealand, and some Australian states, donors are not paid and cannot be anonymous.
In 2000, a website called Donor Sibling Registry was created to help biological children with a common donor connect with each other.
In 2012, a documentary called Anonymous Fathers Day' was released that focuses on donor-conceived children. | 0 | Cryobiology |
The laws of many countries permit IVF for only single individuals, lesbian couples, and persons participating in surrogacy arrangements. | 0 | Cryobiology |
There may be leftover embryos or eggs from IVF procedures if the person for whom they were originally created has successfully carried one or more pregnancies to term, and no longer wishes to use them. With the patient's permission, these may be donated to help others conceive by means of third party reproduction.
In embryo donation, these extra embryos are given to others for transfer, with the goal of producing a successful pregnancy. Embryo recipients have genetic issues or poor-quality embryos or eggs of their own. The resulting child is considered the child of whoever birthed them, and not the child of the donor, the same as occurs with egg donation or sperm donation. As per The National Infertility Association, typically, genetic parents donate the eggs or embryos to a fertility clinic where they are preserved by oocyte cryopreservation or embryo cryopreservation until a carrier is found for them. The process of matching the donation with the prospective parents is conducted by the agency itself, at which time the clinic transfers ownership of the embryos to the prospective parent(s).
Alternatives to donating unused embryos are destroying them (or having them transferred at a time when pregnancy is very unlikely), keeping them frozen indefinitely, or donating them for use in research (rendering them non-viable). Individual moral views on disposing of leftover embryos may depend on personal views on the beginning of human personhood and the definition and/or value of potential future persons, and on the value that is given to fundamental research questions. Some people believe donation of leftover embryos for research is a good alternative to discarding the embryos when patients receive proper, honest and clear information about the research project, the procedures and the scientific values.
During the embryo selection and transfer phases, many embryos may be discarded in favour of others. This selection may be based on criteria such as genetic disorders or the sex. One of the earliest cases of special gene selection through IVF was the case of the Collins family in the 1990s, who selected the sex of their child.
The ethic issues remain unresolved as no worldwide consensus exists in science, religion, and philosophy on when a human embryo should be recognised as a person. For those who believe that this is at the moment of conception, IVF becomes a moral question when multiple eggs are fertilised, begin development, and only a few are chosen for uterus transfer.
If IVF were to involve the fertilisation of only a single egg, or at least only the number that will be transferred, then this would not be an issue. However, this has the chance of increasing costs dramatically as only a few eggs can be attempted at a time. As a result, the couple must decide what to do with these extra embryos. Depending on their view of the embryo's humanity or the chance the couple will want to try to have another child, the couple has multiple options for dealing with these extra embryos. Couples can choose to keep them frozen, donate them to other infertile couples, thaw them, or donate them to medical research. Keeping them frozen costs money, donating them does not ensure they will survive, thawing them renders them immediately unviable, and medical research results in their termination. In the realm of medical research, the couple is not necessarily told what the embryos will be used for, and as a result, some can be used in stem cell research.
In February 2024, the Alabama Supreme Court ruled in LePage v. Center for Reproductive Medicine that cryopreserved embryos were "persons" or "extrauterine children". After Dobbs v. Jackson Women's Health Organization (2022), some antiabortionists had hoped to get a judgement that fetuses and embryos were "person[s]". | 0 | Cryobiology |
QuEChERS is a solid phase extraction method for detection of biocide residues in food. The name is a portmanteau word formed from "quick, easy, cheap, effective, rugged, and safe".
__TOC__ | 1 | Separation Processes |
In 1896, Beijerinck first noted an incompatibility in solutions of agar, a water-soluble polymer, with soluble starch or gelatine. Upon mixing, they separated into two immiscible phases.
Subsequent investigation led to the determination of many other aqueous biphasic systems, of which the polyethylene glycol (PEG) - dextran system is the most extensively studied. Other systems that form aqueous biphases are: PEG - sodium carbonate or PEG and phosphates, citrates or sulfates. Aqueous biphasic systems are used during downstream processing mainly in biotechnological and chemical industries. | 1 | Separation Processes |
The Landau theory of second-order phase transitions has been applied to magnetic phase transitions. The magnetic space group of disordered structure, , transitions to the magnetic space group of the ordered phase, . is a subgroup of , and keeps only the symmetries which have not been broken during the phase transition. This can be tracked numerically by evolution of the order parameter, which belongs to a single irreducible representation of .
Important magnetic phase transitions include the paramagnetic to ferromagnetic transition at the Curie temperature and the paramagnetic to antiferromagnetic transition at the Néel temperature. Differences in the magnetic phase transitions explain why FeO, MnCO, and CoCO are weakly ferromagnetic, whereas the structurally similar CrO and FeCO are purely antiferromagnetic. This theory developed into what is now known as antisymmetric exchange.
A related scheme is the classification of Aizu species which consist of a prototypical non-ferroic magnetic point group, the letter "F" for ferroic, and a ferromagnetic or ferroelectric point group which is a subgroup of the prototypical group which can be reached by continuous motion of the atoms in the crystal structure. | 3 | Magnetic Ordering |
Two joined monosaccharides are called a disaccharide, the simplest kind of polysaccharide. Examples include sucrose and lactose. They are composed of two monosaccharide units bound together by a covalent bond known as a glycosidic linkage formed via a dehydration reaction, resulting in the loss of a hydrogen atom from one monosaccharide and a hydroxyl group from the other. The formula of unmodified disaccharides is CHO. Although there are numerous kinds of disaccharides, a handful of disaccharides are particularly notable.
Sucrose, pictured to the right, is the most abundant disaccharide, and the main form in which carbohydrates are transported in plants. It is composed of one D-glucose molecule and one D-fructose molecule. The systematic name for sucrose, O-α-D-glucopyranosyl-(1→2)-D-fructofuranoside, indicates four things:
* Its monosaccharides: glucose and fructose
* Their ring types: glucose is a pyranose and fructose is a furanose
* How they are linked together: the oxygen on carbon number 1 (C1) of α-D-glucose is linked to the C2 of D-fructose.
* The -oside suffix indicates that the anomeric carbon of both monosaccharides participates in the glycosidic bond.
Lactose, a disaccharide composed of one D-galactose molecule and one D-glucose molecule, occurs naturally in mammalian milk. The systematic name for lactose is O-β-D-galactopyranosyl-(1→4)-D-glucopyranose. Other notable disaccharides include maltose (two D-glucoses linked α-1,4) and cellobiose (two D-glucoses linked β-1,4). Disaccharides can be classified into two types: reducing and non-reducing disaccharides. If the functional group is present in bonding with another sugar unit, it is called a reducing disaccharide or biose. | 2 | Carbohydrates |
Research has examined integrating RO with electrodialysis to improve recovery of valuable deionized products, or to reduce concentrate volumes. | 1 | Separation Processes |
*In case of long range interaction, , the thermodynamic limit is well defined if ; the magnetization remains zero if ; but the magnetization is positive, at low enough temperature, if (infrared bounds).
*As in any nearest-neighbor n-vector model with free boundary conditions, if the external field is zero, there exists a simple exact solution. | 3 | Magnetic Ordering |
An apparent self-protective behaviour, known as "terminal burrowing", or "hide-and-die syndrome", occurs in the final stages of hypothermia. Those affected will enter small, enclosed spaces, such as underneath beds or behind wardrobes. It is often associated with paradoxical undressing. Researchers in Germany claim this is "obviously an autonomous process of the brain stem, which is triggered in the final state of hypothermia and produces a primitive and burrowing-like behavior of protection, as seen in hibernating mammals". This happens mostly in cases where temperature drops slowly. | 0 | Cryobiology |
In the human, the uterine lining (endometrium) needs to be appropriately prepared so that the embryo can implant. In a natural cycle the embryo transfer takes place in the luteal phase at a time where the lining is appropriately undeveloped in relation to the status of the present Luteinizing Hormone. In a stimulated or cycle where a "frozen" embryo is transferred, the recipient woman could be given first estrogen preparations (about 2 weeks), then a combination of estrogen and progesterone so that the lining becomes receptive for the embryo. The time of receptivity is the implantation window. A scientific review in 2013 came to the conclusion that it is not possible to identify one method of endometrium preparation in frozen embryo transfer as being more effective than another.
Limited evidence also supports removal of cervical mucus before transfer. | 0 | Cryobiology |
Embryo transfer techniques allow top quality female livestock to have a greater influence on the genetic advancement of a herd or flock in much the same way that artificial insemination has allowed greater use of superior sires. ET also allows the continued use of animals such as competition mares to continue training and showing, while producing foals. The general epidemiological aspects of embryo transfer indicates that the transfer of embryos provides the opportunity to introduce genetic material into populations of livestock while greatly reducing the risk for transmission of infectious diseases. Recent developments in the sexing of embryos before transfer and implanting has great potential in the dairy and other livestock industries.
Embryo transfer is also used in laboratory mice. For example, embryos of genetically modified strains that are difficult to breed or expensive to maintain may be stored frozen, and only thawed and implanted into a pseudopregnant dam when needed.
On February 19, 2020, the first pair of Cheetah cubs to be conceived through embryo transfer from a surrogate cheetah mother was born at Columbus Zoo in Ohio. | 0 | Cryobiology |
The Curie–Weiss law is an adapted version of Curie's law, which for a paramagnetic material may be written in SI units as follows, assuming :
Here μ is the permeability of free space; M the magnetization (magnetic moment per unit volume), is the magnetic field, and C the material-specific Curie constant:
where is Boltzmann's constant, the number of magnetic atoms (or molecules) per unit volume, the Landé g-factor, the Bohr magneton, the angular momentum quantum number.
For the Curie-Weiss Law the total magnetic field is where is the Weiss molecular field constant and then
which can be rearranged to get
which is the Curie-Weiss Law
where the Curie temperature is | 3 | Magnetic Ordering |
Neuropsychology, in exploring the neural correlates of consciousness, interfaces with neuroscience, although the complexity of the central nervous system is a challenge to its study (that is, its operation resists easy reduction). Context-dependent memory and state-dependent memory show hysteretic aspects of neurocognition. | 3 | Magnetic Ordering |
Transnasal evaporative cooling is a method of inducing the hypothermia process and provides a means of continuous cooling of a person throughout the early stages of targeted temperature management and during movement throughout the hospital environment. This technique uses two cannulae, inserted into a person's nasal cavity, to deliver a spray of coolant mist that evaporates directly underneath the brain and base of the skull. As blood passes through the cooling area, it reduces the temperature throughout the rest of the body.
The method is compact enough to be used at the point of cardiac arrest, during ambulance transport, or within the hospital proper. It is intended to reduce rapidly the person's temperature to below while targeting the brain as the first area of cooling. Research into the device has shown cooling rates of per hour in the brain (measured through infrared tympanic measurement) and per hour for core body temperature reduction. | 0 | Cryobiology |
Normal glass does not transmit below 350 nm, so it is not used for optics in solar-blind systems. Instead calcium fluoride, fused silica, and magnesium fluoride are used as they are transparent to shorter wavelengths. | 4 | Ultraviolet Radiation |
In the case of oxide copper ore, a heap leaching pad will dissolve a dilute copper sulfate solution in a weak sulfuric acid solution. This pregnant leach solution (PLS) is pumped to an extraction mixer settler where it is mixed with the organic phase (a kerosene hosted extractant). The copper transfers to the organic phase, and the aqueous phase (now called raffinate) is pumped back to the heap to recover more copper.
In a high-chloride environment typical of Chilean copper mines, a wash stage will rinse any residual pregnant solution entrained in the organic with clean water.
The copper is then stripped from organic phase in the strip stage into a strong sulfuric acid solution suitable for electrowinning. This strong acid solution is called barren electrolyte when it enters the cell, and strong electrolyte when it is copper bearing after reacting in the cell. | 1 | Separation Processes |
Steinert provides sorting technologies for recycling and mining industries using a variety of sensors, like X-ray, inductive, NIR and color optical sensors and 3D laser camera, which can be combined for sorting a variety of materials. NIR technology is used in the recycling field. | 1 | Separation Processes |
Superferromagnetism is the magnetism of an ensemble of magnetically interacting super-moment-bearing material particles that would be superparamagnetic if they were not interacting. Nanoparticles of iron oxides, such as ferrihydrite (nominally FeOOH), often cluster and interact magnetically. These interactions change the magnetic behaviours of the nanoparticles (both above and below their blocking temperatures) and lead to an ordered low-temperature phase with non-randomly oriented particle super-moments. | 3 | Magnetic Ordering |
* In the case of long-range interaction, , the thermodynamic limit is well defined if ; the magnetization remains zero if ; but the magnetization is positive at low enough temperature if (infrared bounds).
* Polyakov has conjectured that, as opposed to the classical XY model, there is no dipole phase for any ; i.e. at non-zero temperature the correlations cluster exponentially fast. | 3 | Magnetic Ordering |
Carbohydrate metabolism is the series of biochemical processes responsible for the formation, breakdown and interconversion of carbohydrates in living organisms.
The most important carbohydrate is glucose, a simple sugar (monosaccharide) that is metabolized by nearly all known organisms. Glucose and other carbohydrates are part of a wide variety of metabolic pathways across species: plants synthesize carbohydrates from carbon dioxide and water by photosynthesis storing the absorbed energy internally, often in the form of starch or lipids. Plant components are consumed by animals and fungi, and used as fuel for cellular respiration. Oxidation of one gram of carbohydrate yields approximately 16 kJ (4 kcal) of energy, while the oxidation of one gram of lipids yields about 38 kJ (9 kcal). The human body stores between 300 and 500 g of carbohydrates depending on body weight, with the skeletal muscle contributing to a large portion of the storage. Energy obtained from metabolism (e.g., oxidation of glucose) is usually stored temporarily within cells in the form of ATP. Organisms capable of anaerobic and aerobic respiration metabolize glucose and oxygen (aerobic) to release energy, with carbon dioxide and water as byproducts. | 2 | Carbohydrates |
Protein skimming removes certain organic compounds, including proteins and amino acids found in food particles and fish waste, by using the polarity of the protein itself. Due to their intrinsic charge, water-borne proteins are either repelled or attracted by the air/water interface and these molecules can be described as hydrophobic (such as fats or oils) or hydrophilic (such as salt, sugar, ammonia, most amino acids, and most inorganic compounds). However, some larger organic molecules can have both hydrophobic and hydrophilic portions. These molecules are called amphipathic or amphiphilic. Commercial protein skimmers work by generating a large air/water interface, specifically by injecting large numbers of bubbles into the water column. In general, the smaller the bubbles the more effective the protein skimming is because the surface area of small bubbles occupying the same volume is much greater than the same volume of larger bubbles. Large numbers of small bubbles present an enormous air/water interface for hydrophobic organic molecules and amphipathic organic molecules to collect on the bubble surface (the air/water interface). Water movement hastens diffusion of organic molecules, which effectively brings more organic molecules to the air/water interface and lets the organic molecules accumulate on the surface of the air bubbles. This process continues until the interface is saturated, unless the bubble is removed from the water or it bursts, in which case the accumulated molecules release back into the water column. However, it is important to note that further exposure of a saturated air bubble to organic molecules may continue to result in changes as compounds that bind more strongly may replace those molecules with a weaker binding that have already accumulated on the interface. Although some aquarists believe that increasing the contact time (or dwell time as it is sometimes called) is always good, it is incorrect to claim that it is always better to increase the contact time between bubbles and the aquarium water. As the bubbles increase near the top of the protein skimmer water column, they become denser and the water begins to drain and create the foam that will carry the organic molecules to the skimmate collection cup or to a separate skimmate waste collector and the organic molecules, and any inorganic molecules that may have become bound to the organic molecules, will be exported from the water system.
In addition to the proteins removed by skimming, there are a number of other organic and inorganic molecules that are typically removed. These include a variety of fats, fatty acids, carbohydrates, metals such as copper, and trace elements such as iodine. Particulates, phytoplankton, bacteria, and detritus are also removed; this is desired by some aquarists, and is often enhanced by placement of the skimmer before other forms of filtration, lessening the burden on the filtration system as a whole. There is at least one published study that provides a detailed list of the export products removed by the skimmer. Aquarists who keep filter-feeding invertebrates, however, sometimes prefer to keep these particulates in the water to serve as natural food.
Protein skimmers are used to harvest algae and phytoplankton gently enough to maintain viability for culturing or commercial sale as live cultures.
Alternative forms of water filtration have recently come into use, including the algae scrubber, which leaves food particles in the water for corals and small fish to consume, but removes the noxious compounds including ammonia, nitrite, nitrate, and phosphate that protein skimmers do not remove. | 1 | Separation Processes |
So far, we have assumed that the atoms do not interact with each other. Even though this is a reasonable assumption in the case of diamagnetic and paramagnetic substances, this assumption fails in the case of ferromagnetism, where the spins of the atom try to align with each other to the extent permitted by the thermal agitation. In this case, we have to consider the Hamiltonian of the ensemble of the atom. Such a Hamiltonian will contain all the terms described above for individual atoms and terms corresponding to the interaction among the pairs of the atom. Ising model is one of the simplest approximations of such pairwise interaction.
Here the two atoms of a pair are at . Their interaction is determined by their distance vector . In order to simplify the calculation, it is often assumed that interaction happens between neighboring atoms only and is a constant. The effect of such interaction is often approximated as a mean field and, in our case, the Weiss field. | 3 | Magnetic Ordering |
The major complication of IVF is the risk of multiple births. This is directly related to the practice of transferring multiple embryos at embryo transfer. Multiple births are related to increased risk of pregnancy loss, obstetrical complications, prematurity, and neonatal morbidity with the potential for long term damage. Strict limits on the number of embryos that may be transferred have been enacted in some countries (e.g. Britain, Belgium) to reduce the risk of high-order multiples (triplets or more), but are not universally followed or accepted. Spontaneous splitting of embryos in the uterus after transfer can occur, but this is rare and would lead to identical twins. A double blind, randomised study followed IVF pregnancies that resulted in 73 infants, and reported that 8.7% of singleton infants and 54.2% of twins had a birth weight of less than . There is some evidence that making a double embryo transfer during one cycle achieves a higher live birth rate than a single embryo transfer; but making two single embryo transfers in two cycles has the same live birth rate and would avoid multiple pregnancies. | 0 | Cryobiology |
Cryosurgery is also used to treat internal and external tumors as well as tumors in the bone. To cure internal tumors, a hollow instrument called a cryoprobe is used, which is placed in contact with the tumor. Liquid nitrogen or argon gas is passed through the cryoprobe. Ultrasound or MRI is used to guide the cryoprobe and monitor the freezing of the cells. This helps in limiting damage to adjacent healthy tissues. A ball of ice crystals forms around the probe which results in freezing of nearby cells. When it is required to deliver gas to various parts of the tumor, more than one probe is used. After cryosurgery, the frozen tissue is either naturally absorbed by the body in the case of internal tumors, or it dissolves and forms a scab for external tumors. | 0 | Cryobiology |
For quantum mechanical reasons (see exchange interaction or ), the dominant coupling between two dipoles may cause nearest-neighbors to have lowest energy when they are aligned. Under this assumption (so that magnetic interactions only occur between adjacent dipoles) and on a 1-dimensional periodic lattice, the Hamiltonian can be written in the form
where is the coupling constant and dipoles are represented by classical vectors (or "spins") σ, subject to the periodic boundary condition .
The Heisenberg model is a more realistic model in that it treats the spins quantum-mechanically, by replacing the spin by a quantum operator acting upon the tensor product , of dimension . To define it, recall the Pauli spin-1/2 matrices
and for and denote , where is the identity matrix.
Given a choice of real-valued coupling constants and , the Hamiltonian is given by
where the on the right-hand side indicates the external magnetic field, with periodic boundary conditions. The objective is to determine the spectrum of the Hamiltonian, from which the partition function can be calculated and the thermodynamics of the system can be studied.
It is common to name the model depending on the values of , and : if , the model is called the Heisenberg XYZ model; in the case of , it is the Heisenberg XXZ model; if , it is the Heisenberg XXX model. The spin 1/2 Heisenberg model in one dimension may be solved exactly using the Bethe ansatz. In the algebraic formulation, these are related to particular quantum affine algebras and elliptic quantum groups in the XXZ and XYZ cases respectively. Other approaches do so without Bethe ansatz. | 3 | Magnetic Ordering |
Multicolumn countercurrent solvent gradient purification (MCSGP) is a form of chromatography that is used to separate or purify biomolecules from complex mixtures. It was developed at the Swiss Federal Institute of Technology Zürich by Aumann and Morbidelli. The process consists of two to six chromatographic columns which are connected to one another in such a way that as the mixture moves through the columns the compound is purified into several fractions. | 1 | Separation Processes |
DSSCs degrade when exposed to light. In 2014 air infiltration of the commonly-used amorphous Spiro-MeOTAD hole-transport layer was identified as the primary cause of the degradation, rather than oxidation. The damage could be avoided by the addition of an appropriate barrier.
The barrier layer may include UV stabilizers and/or UV absorbing luminescent chromophores (which emit at longer wavelengths which may be reabsorbed by the dye) and antioxidants to protect and improve the efficiency of the cell. | 4 | Ultraviolet Radiation |
Microscope-based diagnostics are widely performed and served as a gold standard in histological analysis. However this procedure generally requires a series time-consuming lab-based procedures including fixation, paraffin embedment, sectioning, and staining to produce microscope slides with optically thin tissue slides (4–6 µm). While in developed regions histology is commonly used, people who live in areas with limited resources can hardly access it and consequently are in need for a low-cost, more efficient way to access pathological diagnosis. The main significance of MUSE system comes from its capacity to produce high-resolution microscopic image with subcellular features in a time-efficient manner with less costs and less lab-expertises requirements.
With 280 nm deep UV excitation and simple but robust hardware design, MUSE system can collect fluorescence signals without the need for fluorescence filtering techniques or complex mathematical image reconstruction. It has potential for generate high quality images containing more information than microscope slides in terms of its 2.5 dimensional features. MUSE images have been validated with diagnostic values. The system is capable to produce images from various tissue type in different sizes, either fresh or fixed. | 4 | Ultraviolet Radiation |
Carbon nanotubes are meant to potentially solve the typical tradeoff between the permeability and the selectivity of RO membranes. CNTs present many ideal characteristics including: mechanical strength, electron affinity, and also exhibiting flexibility during modification. By restructuring carbon nanotubes and coating or impregnating them with other chemical compounds, scientists can manufacture these membranes to have all of the most desirable traits. The hope with CNT membranes is to find a combination of high water permeability while also decreasing the amount of neutral solutes taken out of the water. This would help decrease energy costs and the cost of remineralization after purification through the membrane. | 1 | Separation Processes |
Internally, ferromagnetic materials have a structure that is divided into domains, each of which is a region of uniform magnetization. When a magnetic field is applied, the boundaries between the domains shift and the domains rotate; both of these effects cause a change in the materials dimensions. The reason that a change in the magnetic domains of a material results in a change in the materials dimensions is a consequence of magnetocrystalline anisotropy; it takes more energy to magnetize a crystalline material in one direction than in another. If a magnetic field is applied to the material at an angle to an easy axis of magnetization, the material will tend to rearrange its structure so that an easy axis is aligned with the field to minimize the free energy of the system. Since different crystal directions are associated with different lengths, this effect induces a strain in the material.
The reciprocal effect, the change of the magnetic susceptibility (response to an applied field) of a material when subjected to a mechanical stress, is called the Villari effect. Two other effects are related to magnetostriction: the Matteucci effect is the creation of a helical anisotropy of the susceptibility of a magnetostrictive material when subjected to a torque and the Wiedemann effect is the twisting of these materials when a helical magnetic field is applied to them.
The Villari reversal is the change in sign of the magnetostriction of iron from positive to negative when exposed to magnetic fields of approximately 40 kA/m.
On magnetization, a magnetic material undergoes changes in volume which are small: of the order 10. | 3 | Magnetic Ordering |
When the ovarian follicles have reached a certain degree of development, induction of final oocyte maturation is performed, generally by an injection of human chorionic gonadotropin (hCG). Commonly, this is known as the "trigger shot." hCG acts as an analogue of luteinising hormone, and ovulation would occur between 38 and 40 hours after a single HCG injection, but the egg retrieval is performed at a time usually between 34 and 36 hours after hCG injection, that is, just prior to when the follicles would rupture. This avails for scheduling the egg retrieval procedure at a time where the eggs are fully mature. HCG injection confers a risk of ovarian hyperstimulation syndrome. Using a GnRH agonist instead of hCG eliminates most of the risk of ovarian hyperstimulation syndrome, but with a reduced delivery rate if the embryos are transferred fresh. For this reason, many centers will freeze all oocytes or embryos following agonist trigger. | 0 | Cryobiology |
Isopropyl β--1-thiogalactopyranoside (IPTG) is a molecular biology reagent. This compound is a molecular mimic of allolactose, a lactose metabolite that triggers transcription of the lac operon, and it is therefore used to induce protein expression where the gene is under the control of the lac operator. | 2 | Carbohydrates |
Normally, any ferromagnetic or ferrimagnetic material undergoes a transition to a paramagnetic state above its Curie temperature. Superparamagnetism is different from this standard transition since it occurs below the Curie temperature of the material.
Superparamagnetism occurs in nanoparticles which are single-domain, i.e. composed of a single magnetic domain. This is possible when their diameter is below 3–50 nm, depending on the materials. In this condition, it is considered that the magnetization of the nanoparticles is a single giant magnetic moment, sum of all the individual magnetic moments carried by the atoms of the nanoparticle. Those in the field of superparamagnetism call this "macro-spin approximation".
Because of the nanoparticle’s magnetic anisotropy, the magnetic moment has usually only two stable orientations antiparallel to each other, separated by an energy barrier. The stable orientations define the nanoparticle’s so called “easy axis”. At finite temperature, there is a finite probability for the magnetization to flip and reverse its direction. The mean time between two flips is called the Néel relaxation time and is given by the following Néel–Arrhenius equation:
where:
* is thus the average length of time that it takes for the nanoparticle’s magnetization to randomly flip as a result of thermal fluctuations.
* is a length of time, characteristic of the material, called the attempt time or attempt period (its reciprocal is called the attempt frequency); its typical value is between 10 and 10 second.
* K is the nanoparticle’s magnetic anisotropy energy density and V its volume. KV is therefore the energy barrier associated with the magnetization moving from its initial easy axis direction, through a “hard plane”, to the other easy axis direction.
* k is the Boltzmann constant.
* T is the temperature.
This length of time can be anywhere from a few nanoseconds to years or much longer. In particular, it can be seen that the Néel relaxation time is an exponential function of the grain volume, which explains why the flipping probability becomes rapidly negligible for bulk materials or large nanoparticles. | 3 | Magnetic Ordering |
UV is an investigative tool at the crime scene helpful in locating and identifying bodily fluids such as semen, blood, and saliva. For example, ejaculated fluids or saliva can be detected by high-power UV sources, irrespective of the structure or colour of the surface the fluid is deposited upon. UV–vis microspectroscopy is also used to analyze trace evidence, such as textile fibers and paint chips, as well as questioned documents.
Other applications include the authentication of various collectibles and art, and detecting counterfeit currency. Even materials not specially marked with UV sensitive dyes may have distinctive fluorescence under UV exposure or may fluoresce differently under short-wave versus long-wave ultraviolet. | 4 | Ultraviolet Radiation |
Glycan arrays have been used to characterize previously unknown biochemical interactions. For example, photo-generated glycan arrays have been used to characterize the immunogenic properties of a tetrasaccharide found on the surface of anthrax spores. Hence, glycan array technology can be used to study the specificity of host-pathogen interactions.
Early on, glycan arrays were proven useful in determining the specificity of the Hemagglutinin (influenza) of the Influenza A virus binding to the host and distinguishing across different strains of flu (including avian from mammalian). This was shown with CFG arrays as well as customised arrays.
Cross-platform benchmarks led to highlight the effect of glycan presentation and spacing on binding.
Glycan arrays are possibly combined with other techniques such as Surface Plasmon Resonance (SPR) to refine the characterisation of glycan-binding. For example, this combination led to demonstrate the calcium-dependent heparin binding of Annexin A1 that is involved in several biological processes including inflammation, apoptosis and membrane trafficking. | 2 | Carbohydrates |
Osazone formation was developed by Emil Fischer, who used the reaction as a test to identify monosaccharides.
The formation of a pair of hydrazone functionalities involves both oxidation and condensation reactions. Since the reaction requires a free carbonyl group, only "reducing sugars" participate. Sucrose, which is nonreducing, does not form an osazone. | 2 | Carbohydrates |
The LLE describes an anisotropic magnet. The equation is described in as follows: It is an equation for a vector field S, in other words a function on R taking values in R. The equation depends on a fixed symmetric 3 by 3 matrix J, usually assumed to be diagonal; that is, . It is given by Hamilton's equation of motion for the Hamiltonian
(where J(S) is the quadratic form of J applied to the vector S)
which is
In 1+1 dimensions this equation is
In 2+1 dimensions this equation takes the form
which is the (2+1)-dimensional LLE. For the (3+1)-dimensional case LLE looks like | 3 | Magnetic Ordering |
Certain kinds of IVF have been shown to lead to distortions in the sex ratio at birth. Intracytoplasmic sperm injection (ICSI), which was first applied in 1991, leads to slightly more female births (51.3% female). Blastocyst transfer, which was first applied in 1984, leads to significantly more male births (56.1% male). Standard IVF done at the second or third day leads to a normal sex ratio.
Epigenetic modifications caused by extended culture leading to the death of more female embryos has been theorised as the reason why blastocyst transfer leads to a higher male sex ratio; however, adding retinoic acid to the culture can bring this ratio back to normal. A second theory is that the male-biased sex ratio may due to a higher rate of selection of male embryos. Male embryos develop faster in vitro, and thus may appear more viable for transfer. | 0 | Cryobiology |
Oocyte selection is a procedure that is performed prior to in vitro fertilization, in order to use oocytes with maximal chances of resulting in pregnancy. In contrast, embryo selection takes place after fertilization.
Not all women can conceive naturally, leaving them with a need for technologies and research that can help them have children. Women who might not be able to have their kids naturally may have the option of in vitro fertilization. In vitro fertilization can be a series of treatments that involves the fertilization of a mature egg with a sperm in a laboratory. Oocyte selection is a part the process for in vitro fertilization. An Oocyte is an egg/ovum that is not fully mature or developed and has not been fertilized; Therefore an oocyte is an undeveloped ovum.
__TOC__ | 0 | Cryobiology |
There is evidence that immunological mechanisms may injure hypothermically perfused kidneys after reimplantation if the perfusate contained specific antibody. Cross described two pairs of human cadaver kidneys that were perfused simultaneously with cryoprecipitated plasma containing type specific HLA antibody to one of the pairs. Both these kidneys suffered early arterial thrombosis. Light described similar hyperacute rejection following perfusion storage and showed that the cryoprecipitated plasma used contained cytotoxic IgM antibody. This potential danger of using cryoprecipitated plasma was demonstrated experimentally by Filo who perfused dog kidneys for 24 hours with specifically sensitised cryoprecipitated dog plasma and found that he could induce glomerular and vascular lesions with capillary engorgement, endothelial swelling, infiltration by polymorphonuclear leucocytes and arterial thrombosis. Immunofluorescent microscopy demonstrated specific binding of IgG along endothelial surfaces, in glomeruli, and also in vessels. After reimplantation, complement fixation and tissue damage occurred in a similar pattern. There was some correlation between the severity of the histological damage and subsequent function of the kidneys.
Many workers have attempted to prevent kidneys rewarming during reimplantation but only Cohen has described using a system of active cooling. Measurements of lysosomal enzyme release from kidneys subjected to sham anastomoses, when either in or out of the cooling system, demonstrated how sensitive kidneys were to rewarming after a period of cold storage, and confirmed the effectiveness of the cooling system in preventing enzyme release. A further factor in minimising injury at the reimplantation operations may have been that the kidneys were kept at 7 °C within the cooling coil, which was within a degree of the temperature used during perfusion storage, so that the kidneys were not subjected to the greater changes in temperature that would have occurred if ice cooling had been used.
Dempster described using slow release of the vascular clamps at the end of kidney reimplantation operations to avoid injuring the kidney, but other workers have not mentioned whether or not they used this manoeuvre. After Cohen found vascular injury with intra renal bleeding after 3 days of perfusion storage, a technique of slow revascularisation was used for all subsequent experiments, with the aim of giving the intra- renal vessels time to recover their tone sufficiently to prevent full systolic pressure being applied to the fragile glomerular vessels. The absence of gross vascular injury in his later perfusions may be attributable to the use of this manoeuvre. | 0 | Cryobiology |
Magnetocrystalline anisotropy has a great influence on industrial uses of ferromagnetic materials. Materials with high magnetic anisotropy usually have high coercivity, that is, they are hard to demagnetize. These are called "hard" ferromagnetic materials and are used to make permanent magnets. For example, the high anisotropy of rare-earth metals is mainly responsible for the strength of rare-earth magnets. During manufacture of magnets, a powerful magnetic field aligns the microcrystalline grains of the metal such that their "easy" axes of magnetization all point in the same direction, freezing a strong magnetic field into the material.
On the other hand, materials with low magnetic anisotropy usually have low coercivity, their magnetization is easy to change. These are called "soft" ferromagnets and are used to make magnetic cores for transformers and inductors. The small energy required to turn the direction of magnetization minimizes core losses, energy dissipated in the transformer core when the alternating current changes direction. | 3 | Magnetic Ordering |
Classification of nerve damage was well-defined by Sir Herbert Seddon and Sunderland in a system that remains in use. The adjacent table details the forms (neurapraxia, axonotmesis and neurotmesis) and degrees of nerve injury that occur as a result of exposure to various temperatures.
Cryoneurolysis treatments that use nitrous oxide (boiling point of −88.5 °C) as the coolant fall in the range of an axonotmesis injury, or 2nd degree injury, according to the Sunderland classification system. Treatments of the nerve in this temperature range are reversible. Nerves treated in this temperature range experience a disruption of the axon, with Wallerian degeneration occurring distal to the site of injury. The axon and myelin sheath are affected, but all of the connective tissues (endoneurium, perineurium, and epineurium) remain intact. Following Wallerian degeneration, the axon regenerates along the original nerve path at a rate of approximately 1–2 mm per day.
Cryoneurolysis differs from cryoablation in that cryoablation treatments utilize liquid nitrogen (boiling point of −195.8 °C) as the coolant, and therefore, fall into the range of a neurotmesis injury, or 3rd degree injury according to the Sunderland classification. Treatments of the nerve in this temperature range are irreversible. Nerves treated in this temperature range experience a disruption of both the axon and the endoneurium connective tissue layer. | 0 | Cryobiology |
* Cryogenics, the study of the production and behaviour of materials at very low temperatures and the study of producing extremely low temperatures
* Cryoelectronics, the study of superconductivity under cryogenic conditions and its applications
* Cryosphere, those portions of Earth's surface where water ice naturally occurs
* Cryotron, a switch that uses superconductivity
* Cryovolcano, a theoretical type of volcano that erupts volatiles instead of molten rock | 0 | Cryobiology |
UVGI is often used to disinfect equipment such as safety goggles, instruments, pipettors, and other devices. Lab personnel also disinfect glassware and plasticware this way. Microbiology laboratories use UVGI to disinfect surfaces inside biological safety cabinets ("hoods") between uses. | 4 | Ultraviolet Radiation |
Industrial separation processes are technical procedures which are used in industry to separate a product from impurities or other products. The original mixture may either be a natural resource (like ore, oil or sugar cane) or the product of a chemical reaction (like a drug or an organic solvent). | 1 | Separation Processes |
A typical sublimation apparatus separates a mix of appropriate solid materials in a vessel in which it applies heat under a controllable atmosphere (air, vacuum or inert gas). If the material is not at first solid, then it may freeze under reduced pressure. Conditions are so chosen that the solid volatilizes and condenses as a purified compound on a cooled surface, leaving the non-volatile residual impurities or solid products behind.
The form of the cooled surface often is a so-called cold finger which for very low-temperature sublimation may actually be cryogenically cooled. If the operation is a batch process, then the sublimed material can be collected from the cooled surface once heating ceases and the vacuum is released. Although this may be quite convenient for small quantities, adapting sublimation processes to large volume is generally not practical with the apparatus becoming extremely large and generally needing to be disassembled to recover products and remove residue.
Among the advantages of applying the principle to certain materials are the comparatively low working temperatures, reduced exposure to gases such as oxygen that might harm certain products, and the ease with which it can be performed on extremely small quantities. The same apparatus may also be used for conventional distillation of extremely small quantities due to the very small volume and surface area between evaporating and condensing regions, although this is generally only useful if the cold finger can be cold enough to solidify the condensate. | 1 | Separation Processes |
Sensor-based sorting can be applied to separate the coarse fraction of the run-of-mine material according to its characteristics. Possible separation criteria are grade, mineralogy, grade and grindability amongst others. Treating different ore types separately results either in an optimised cash flow in the sense, that revenue ist shifted to an earlier point in time, or increased overall recovery which translates to higher productivity and thus revenue. If two separate plant lines are installed, the increased productivity must compensate for the overall higher capital expenditure and operating costs. | 1 | Separation Processes |
Fresh blastocyst (day 5 to 6) stage transfer seems to be more effective than cleavage (day 2 or 3) stage transfer in assisted reproductive technologies. The Cochrane study showed a small improvement in live birth rate per couple for blastocyst transfers. This would mean that for a typical rate of 31% in clinics that use early cleavage stage cycles, the rate would increase to 32% to 41% live births if clinics used blastocyst transfer. Recent systematic review showed that along with selection of embryo, the techniques followed during transfer procedure may result in successful pregnancy outcome. The following interventions are supported by the literature for improving pregnancy rates:
Abdominal ultrasound guidance for embryo transfer
Removal of cervical mucus
Use of soft embryo transfer catheters
Placement of embryo transfer tip in the upper or middle (central) area of the uterine cavity, greater than 1 cm from the fundus, for embryo expulsion
Immediate ambulation once the embryo transfer procedure is completed | 0 | Cryobiology |
The term cryostasis was introduced to name the reversible preservation technology for live biological objects which is based on using clathrate-forming gaseous substances under increased hydrostatic pressure and hypothermic temperatures.
Living tissues cooled below the freezing point of water are damaged by the dehydration of the cells as ice is formed between the cells. The mechanism of freezing damage in living biological tissues has been elucidated by Renfret.
The vapor pressure of the ice is lower than the vapor pressure of the solute water in the surrounding cells and as heat is removed at the freezing point of the solutions, the ice crystals grow between the cells, extracting water from them. As the ice crystals grow, the volume of the cells shrinks, and the cells are crushed between the ice crystals. Additionally, as the cells shrink, the solutes inside the cells are concentrated in the remaining water, increasing the intracellular ionic strength and interfering with the organization of the proteins and other organized intercellular structures. Eventually, the solute concentration inside the cells reaches the eutectic and freezes. The final state of frozen tissues is pure ice in the former extracellular spaces, and inside the cell membranes a mixture of concentrated cellular components in ice and bound water. In general, this process is not reversible to the point of restoring the tissues to life.
Cryostasis utilizes clathrate-forming gases that penetrate and saturate the biological tissues causing clathrate hydrates formation (under specific pressure-temperature conditions) inside the cells and in the extracellular matrix. Clathrate hydrates are a class of solids in which gas molecules occupy "cages" made up of hydrogen-bonded water molecules. These "cages" are unstable when empty, collapsing into conventional ice crystal structure, but they are stabilised by the inclusion of the gas molecule within them. Most low molecular weight gases (including CH, HS, Ar, Kr, and Xe) will form a hydrate under some pressure-temperature conditions.
Clathrates formation will prevent the biological tissues from dehydration which will cause irreversible inactivation of intracellular enzymes. | 0 | Cryobiology |
Botanical gardens, zoos, and aquariums are the most conventional methods of ex situ conservation. Also in ex situ conservation, all of which house whole, protected specimens for breeding and reintroduction into the wild when necessary and possible. These facilities provide not only housing and care for specimens of endangered species, but also have an educational value. They inform the public of the threatened status of endangered species and of those factors which cause the threat, with the hope of creating public interest in stopping and reversing those factors which jeopardize a species survival in the first place. They are the most publicly visited ex situ' conservation sites, with the WZCS (World Zoo Conservation Strategy) estimating that the 1,100 organized zoos in the world receive more than 600 million visitors annually. Globally there is an estimated total of 2,107 aquaria and zoos in 125 countries. Additionally many private collectors or other not-for-profit groups hold animals and they engage in conservation or reintroduction efforts. Similarly there are approximately 2,000 botanical gardens in 148 counties cultivating or storing an estimated 80,000 taxa of plants. | 0 | Cryobiology |
For ice, recrystallization refers to the growth of larger crystals at the expense of smaller ones. Some biological antifreeze proteins have been shown to inhibit this process, and the effect may be relevant in freezing-tolerant organisms. | 1 | Separation Processes |
The spin ice model is only one subdivision of frustrated systems. The word frustration was initially introduced to describe a systems inability to simultaneously minimize the competing interaction energy between its components. In general frustration is caused either by competing interactions due to site disorder (see also the Villain model') or by lattice structure such as in the triangular, face-centered cubic (fcc), hexagonal-close-packed, tetrahedron, pyrochlore and kagome lattices with antiferromagnetic interaction. So frustration is divided into two categories: the first corresponds to the spin glass, which has both disorder in structure and frustration in spin; the second is the geometrical frustration with an ordered lattice structure and frustration of spin. The frustration of a spin glass is understood within the framework of the RKKY model, in which the interaction property, either ferromagnetic or anti-ferromagnetic, is dependent on the distance of the two magnetic ions. Due to the lattice disorder in the spin glass, one spin of interest and its nearest neighbors could be at different distances and have a different interaction property, which thus leads to different preferred alignment of the spin. | 3 | Magnetic Ordering |
Alternative organophosphorus compounds include trioctylphosphine oxide and bis(2,4,4-trimethyl pentyl)phosphinic acid. Secondary, tertiary, and quaternary amines have also been used for some uranium extractions. Compared to phosphate extractants, amines are more selective for uranium, extract the uranium faster, and are easily stripped with a wider variety of reagents. However, the phosphates are more tolerant of solids in the feed solution and show faster phase separation. | 1 | Separation Processes |
The columns are made of stainless steel. Conical vanes are attached alternately to the wall of the column and to a central rotating shaft. The product is poured in at the top under vacuum, and steam is pumped into the column from below. The vanes provide a large surface area over which volatile compounds can evaporate into the steam, and the rotation ensures a thin layer of the product is constantly moved over the moving cone. It typically takes 20 seconds for the liquid to move through the column, and industrial columns might process . The temperature and pressure can be adjusted depending on the compounds targeted. | 1 | Separation Processes |
Hot filtration can be used to separate "compound A" from both "impurity B" and some "insoluble matter C". This technique normally uses a single-solvent system as described above. When both "compound A" and "impurity B" are dissolved in the minimum amount of hot solvent, the solution is filtered to remove "insoluble matter C". This matter may be anything from a third impurity compound to fragments of broken glass. For a successful procedure, one must ensure that the filtration apparatus is hot in order to stop the dissolved compounds from crystallizing from the solution during filtration, thus forming crystals on the filter paper or funnel.
One way to achieve this is to heat a conical flask containing a small amount of clean solvent on a hot plate. A filter funnel is rested on the mouth, and hot solvent vapors keep the stem warm. Jacketed filter funnels may also be used. The filter paper is preferably fluted, rather than folded into a quarter; this allows quicker filtration, thus less opportunity for the desired compound to cool and crystallize from the solution.
Often it is simpler to do the filtration and recrystallization as two independent and separate steps. That is dissolve "compound A" and "impurity B" in a suitable solvent at room temperature, filter (to remove insoluble compound/glass), remove the solvent and then recrystallize using any of the methods listed above. | 1 | Separation Processes |
Of course, the composition of the material that is used as the counter electrode is extremely important to creating a working photovoltaic, as the valence and conduction energy bands must overlap with those of the redox electrolyte species to allow for efficient electron exchange.
In 2018, Jin et al. prepared ternary nickel cobalt selenide (NiCoSe) films at various stoichiometric ratios of nickel and cobalt to understand its impact on the resulting cell performance. Nickel and cobalt bimetallic alloys were known to have outstanding electron conduction and stability, so optimizing its stoichiometry would ideally produce a more efficient and stable cell performance than its singly metallic counterparts. Such is the result that Jin et al. found, as NiCoSe achieved superior power conversion efficiency (8.61%), lower charge transfer impedance, and higher electrocatalytic ability than both its platinum and binary selenide counterparts. | 4 | Ultraviolet Radiation |
Mannans are polymers containing the sugar mannose as a principal component.
They are a type of polysaccharide found in hemicellulose, a major source of biomass found in higher plants such as softwoods. These polymers also typically contain two other sugars, galactose and glucose. They are often branched (unlike cellulose). | 2 | Carbohydrates |
With these technologies, cold water circulates through a blanket, or torso wraparound vest and leg wraps. To lower temperature with optimal speed, 70% of a persons surface area should be covered with water blankets. The treatment represents the most well studied means of controlling body temperature. Water blankets lower a persons temperature exclusively by cooling a person's skin and accordingly require no invasive procedures.
Water blankets possess several undesirable qualities. They are susceptible to leaking, which may represent an electrical hazard since they are operated in close proximity to electrically powered medical equipment. The Food and Drug Administration also has reported several cases of external cooling blankets causing significant burns to the skin of person. Other problems with external cooling include overshoot of temperature (20% of people will have overshoot), slower induction time versus internal cooling, increased compensatory response, decreased patient access, and discontinuation of cooling for invasive procedures such as the cardiac catheterization.
If therapy with water blankets is given along with two litres of cold intravenous saline, people can be cooled to in 65 minutes. Most machines now come with core temperature probes. When inserted into the rectum, the core body temperature is monitored and feedback to the machine allows changes in the water blanket to achieve the desired set temperature. In the past some of the models of cooling machines have produced an overshoot in the target temperature and cooled people to levels below , resulting in increased adverse events. They have also rewarmed patients at too fast a rate, leading to spikes in intracranial pressure. Some of the new models have more software that attempt to prevent this overshoot by utilizing warmer water when the target temperature is close and preventing any overshoot. Some of the new machines now also have 3 rates of cooling and warming; a rewarming rate with one of these machines allows a patient to be rewarmed at a very slow rate of just an hour in the "automatic mode", allowing rewarming from to over 24 hours. | 0 | Cryobiology |
The function of lectins in plants (legume lectin) is still uncertain. Once thought to be necessary for rhizobia binding, this proposed function was ruled out through lectin-knockout transgene studies.
The large concentration of lectins in plant seeds decreases with growth, and suggests a role in plant germination and perhaps in the seed's survival itself. The binding of glycoproteins on the surface of parasitic cells also is believed to be a function. Several plant lectins have been found to recognize noncarbohydrate ligands that are primarily hydrophobic in nature, including adenine, auxins, cytokinin, and indole acetic acid, as well as water-soluble porphyrins. These interactions may be physiologically relevant, since some of these molecules function as phytohormones.
Lectin receptor kinases (LecRKs) are believed to recognize damage associated molecular patterns (DAMPs), which are created or released from herbivore attack. In Arabidopsis, legume-type LecRKs Clade 1 has 11 LecRK proteins. LecRK-1.8 has been reported to recognize extracellular NAD molecules and LecRK-1.9 has been reported to recognize extracellular ATP molecules. | 2 | Carbohydrates |
The reaction mechanism is that of the related Hofmann degradation.
At first the carbonic acid amide (1) reacts with the sodium hypochlorite. After the separation of water and chloride an amine with a free bond is built 2. The intermediate (3) is generated by rearrangement. In the next step a hydrolysis takes place. Water is added at the carbon-atom with the number 1. A hydroxylic group is generated. The last step is that an acidic amide is separated and the aldehyde (4) is generated. | 2 | Carbohydrates |
Under a given uni-axial mechanical stress , the flux density for a given magnetizing field strength may increase or decrease. The way in which a material responds to stresses depends on its saturation magnetostriction . For this analysis, compressive stresses are considered as negative, whereas tensile stresses are positive.<br />
According to Le Chatelier's principle:
This means, that when the product is positive, the flux density increases under stress. On the other hand, when the product is negative, the flux density decreases under stress. This effect was confirmed experimentally. | 3 | Magnetic Ordering |
Calculation of multipolar exchange interactions remains a challenging issue in many aspects. Although there were many works based on fitting the model Hamiltonians with experiments, predictions of the coupling constants based on first-principle schemes remain lacking. Currently there are two studies implemented first-principles approach to explore multipolar exchange interactions. An early study was developed in 80's. It is based on a mean field approach that can greatly reduce the complexity of coupling constants induced by RKKY mechanism, so the multipolar exchange Hamiltonian can be described by just a few unknown parameters and can be obtained by fitting with experiment data. Later on, a first-principles approach to estimate the unknown parameters was further developed and got good agreements with a few selected compounds, e.g. cerium momnpnictides. Another first-principle approach was also proposed recently. It maps all the coupling constants induced by all static exchange mechanisms to a series of DFT+U total energy calculations and got agreement with uranium dioxide. | 3 | Magnetic Ordering |
A primary advantage of curing with ultraviolet light is the speed at which a material can be processed. Speeding up the curing, or drying step, in a process can reduce flaws and errors by decreasing time that an ink or coating spends as wet. This can increase the quality of a finished item, and potentially allow for greater consistency. Another benefit to decreasing manufacturing time is that less space needs to be devoted to storing items which can not be used until the drying step is finished.
Because UV energy has unique interactions with many different materials, UV curing allows for the creation of products with characteristics not achievable via other means. This has led to UV curing becoming fundamental in many fields of manufacturing and technology, where changes in strength, hardness, durability, chemical resistance, and many other properties are required. | 4 | Ultraviolet Radiation |
The waste discharge can be used as land stabilizer as dry bio-solids that can be distributed to the market. The land stabilizer is used in reclaiming marginal land such as mining waste land. This process will help to restore the land to its initial appearance. | 1 | Separation Processes |
Laboratories have developed grading methods to judge oocyte 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. A small prospectively randomized study in 2016 reported poorer embryo quality and more staff time in an automated time-lapse embryo imaging device compared to conventional embryology. Active efforts to develop a more accurate embryo selection analysis based on Artificial Intelligence and Deep Learning are underway. Embryo Ranking Intelligent Classification Algorithm (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 |
Psychrophiles or cryophiles (adj. psychrophilic or cryophilic) are extremophilic organisms that are capable of growth and reproduction in low temperatures, ranging from to . They are found in places that are permanently cold, such as the polar regions and the deep sea. They can be contrasted with thermophiles, which are organisms that thrive at unusually high temperatures, and mesophiles at intermediate temperatures. Psychrophile is Greek for cold-loving, .
Many such organisms are bacteria or archaea, but some eukaryotes such as lichens, snow algae, phytoplankton, fungi, and wingless midges, are also classified as psychrophiles. | 0 | Cryobiology |
Sucrose is a disaccharide, a molecule composed of the two monosaccharides glucose, and fructose. Invertase is the enzyme cleaves the glycosidic linkage between the glucose and fructose molecules.
In most wines, there will be very little sucrose, since it is not a natural constituent of grapes and sucrose added for the purpose of chaptalisation will be consumed in the fermentation. The exception to this rule is Champagne and other sparkling wines, to which an amount of liqueur dexpédition (typically sucrose dissolved in a still wine) is added after the second fermentation in bottle, a practice known as dosage'. | 2 | Carbohydrates |
Ultraviolet illumination can be produced from longer wavelengths using non-linear optical materials. These can be a second harmonic generator. They must have a suitable birefringence in order to phase match the output frequency doubled UV light. One compound commercially used is L-arginine phosphate monohydrate known as LAP. Research is underway for substances that are very non-linear, have a suitable birefringence, are transparent in the spectrum and have a high degree of resistance to damage from lasers. | 4 | Ultraviolet Radiation |
Lactulose is used as a test of small intestine bacterial overgrowth (SIBO). Recently, the reliability of it for diagnosing SIBO has been seriously questioned. A large amount of it is given with subsequent testing of molecular hydrogen gas in the breath. The test is positive if an increase in exhaled hydrogen occurs before that which would be expected by normal digestion by the normal gut flora in the colon. An earlier result has been hypothesized to indicate digestion occurring within the small intestine. An alternate explanation for differences in results is the variance in small bowel transit time among tested subjects. | 2 | Carbohydrates |
Amylopectin is a key component in the crystallization of starch’s final configuration, accounting for 70-80% of the final mass. Composed of α-glucose, it is formed in plants as a primary measure of energy storage in tandem with this structural metric.
Amylopectin bears a straight/linear chain along with a number of side chains which may be branched further. Glucose units are linked in a linear way with α(1→4) Glycosidic bonds. Branching usually occurs at intervals of 25 residues. At the places of origin of a side chain, the branching that takes place bears an α(1→6) glycosidic bond, resulting in a soluble molecule that can be quickly degraded as it has many end points onto which enzymes can attach. Wolform and Thompson (1956) have also reported α(1→3)linkages in case of Amylopectin. Amylopectin contains a larger number of Glucose units (2000 to 200,000) as compared to Amylose containing 200 to 1000 α-Glucose units. In contrast, amylose contains very few α(1→6) bonds, or even none at all. This causes amylose to be hydrolyzed more slowly, but also creates higher density and insolubility.
Amylopectin is divided into A and B helical chains of α-glucose. A chains are chains that carry no other chains, resulting in an eventual terminus, whereas B chains are chains that do carry other chains, perpetuating the amylopectin polymer. The ratio between these is usually between 0.8 to 1.4.
The formation of chain structures has a direct impact on the overall strength of the polymeric whole; the longer a chain is, the more differing the effects amylopectin will have on starch’s morphology. Packing of chains, inter block chain length (IB-CL), also has been correlated to have a direct positive impact on the gelatinization temperature of starch granules. In tandem, the IB-CL will increase as the length of B chains increases, meaning that as the length of individual B chains increases, as does the blocks between connections with other chains. Finally, in general, the more densely packed the resulting molecule of amylopectin, the higher the strength of the starch gel as a whole unit.
Starch utilizes the density-strength correlation of amylopectin as a measure of forming dense, strong bricks as a basis for the final starch configuration. Amylopectin in starch is formed into helices to compose hexagonal structures that will subsequently be differentiated into A (cereal) and B (high-amylose; tubular) type starch. Structurally, A is more compact, while B is looser, hence the higher concentration of amylose. | 2 | Carbohydrates |
Altermagnets exhibit an unusual combination of ferromagnetic and antiferromagnetic properties, and remarkably more closely resemble those of ferromagnets. Hallmarks of altermagnetic materials such as the anomalous Hall effect have been observed before (but this effect occurs also in other magnetically compensated systems such as non-collinear antiferromagnets). Altermagnets also exhibit unique properties such as anomalous and spin currents that can change sign as the crystal rotates. | 3 | Magnetic Ordering |
Galactomannans are polysaccharides consisting of a mannose backbone with galactose side groups, more specifically, a (1-4)-linked beta-D-mannopyranose backbone with branchpoints from their 6-positions linked to alpha-D-galactose, (i.e. 1-6-linked alpha-D-galactopyranose).
In order of increasing number of mannose-to-galactose ratio:
*fenugreek gum, mannose:galactose ~1:1
*guar gum, mannose:galactose ~2:1
*tara gum, mannose:galactose ~3:1
*locust bean gum or carob gum, mannose:galactose ~4:1
*cassia gum, mannose:galactose ~5:1
Galactomannans are often used in food products to increase the viscosity of the water phase.
Guar gum has been used to add viscosity to artificial tears, but is not as stable as carboxymethylcellulose. | 2 | Carbohydrates |
Glucocerebroside (also called glucosylceramide) is any of the cerebrosides in which the monosaccharide head group is glucose. | 2 | Carbohydrates |
Psychrotrophic microbes are able to grow at temperatures below , but have better growth rates at higher temperatures. Psychrotrophic bacteria and fungi are able to grow at refrigeration temperatures, and can be responsible for food spoilage and as foodborne pathogens such as Yersinia. They provide an estimation of the product's shelf life, but also they can be found in soils, in surface and deep sea waters, in Antarctic ecosystems, and in foods.
Psychrotrophic bacteria are of particular concern to the dairy industry. Most are killed by pasteurization; however, they can be present in milk as post-pasteurization contaminants due to less than adequate sanitation practices. According to the Food Science Department at Cornell University, psychrotrophs are bacteria capable of growth at temperatures at or less than . At freezing temperatures, growth of psychrotrophic bacteria becomes negligible or virtually stops.
All three subunits of the RecBCD enzyme are essential for physiological activities of the enzyme in the Antarctic Pseudomonas syringae, namely, repairing of DNA damage and supporting the growth at low temperature. The RecBCD enzymes are exchangeable between the psychrophilic P. syringae and the mesophilic E. coli when provided with the entire protein complex from same species. However, the RecBC proteins (RecBCPs and RecBCEc) of the two bacteria are not equivalent; the RecBCEc is proficient in DNA recombination and repair, and supports the growth of P. syringae at low temperature, while RecBCPs is insufficient for these functions. Finally, both helicase and nuclease activity of the RecBCDPs are although important for DNA repair and growth of P. syringae at low temperature, the RecB-nuclease activity is not essential in vivo. | 0 | Cryobiology |
Plants are under horticulture care, but the environment is managed to near natural conditions. This occurs with either restored or semi-natural environments. This technique is primarily used for taxa that are rare or in areas where habitat has been severely degraded. | 0 | Cryobiology |
There are various ways to describe ferrimagnets, the simplest of which is with mean-field theory. In mean-field theory the field acting on the atoms can be written as
where is the applied magnetic field, and is field caused by the interactions between the atoms. The following assumption then is
Here is the average magnetization of the lattice, and is the molecular field coefficient. When we allow and to be position- and orientation-dependent, we can then write it in the form
where is the field acting on the i-th substructure, and is the molecular field coefficient between the i-th and k-th substructures. For a diatomic lattice we can designate two types of sites, a and b. We can designate the number of magnetic ions per unit volume, the fraction of the magnetic ions on the a sites, and the fraction on the b sites. This then gives
It can be shown that and that unless the structures are identical. favors a parallel alignment of and , while favors an anti-parallel alignment. For ferrimagnets, , so it will be convenient to take as a positive quantity and write the minus sign explicitly in front of it. For the total fields on a and b this then gives
Furthermore, we will introduce the parameters and which give the ratio between the strengths of the interactions. At last we will introduce the reduced magnetizations
with the spin of the i-th element. This then gives for the fields:
The solutions to these equations (omitted here) are then given by
where is the Brillouin function. The simplest case to solve now is . Since , this then gives the following pair of equations:
with and . These equations do not have a known analytical solution, so they must be solved numerically to find the temperature dependence of . | 3 | Magnetic Ordering |
A group of researchers at the École Polytechnique Fédérale de Lausanne (EPFL) has reportedly increased the thermostability of DSC by using amphiphilic ruthenium sensitizer in conjunction with quasi-solid-state gel electrolyte. The stability of the device matches that of a conventional inorganic silicon-based solar cell. The cell sustained heating for 1,000 h at 80 °C.
The group has previously prepared a ruthenium amphiphilic dye Z-907 (cis-Ru(Hdcbpy)(dnbpy)(NCS), where the ligand Hdcbpy is 4,4′-dicarboxylic acid-2,2′-bipyridine and dnbpy is 4,4′-dinonyl-2,2′-bipyridine) to increase dye tolerance to water in the electrolytes. In addition, the group also prepared a quasi-solid-state gel electrolyte with a 3-methoxypropionitrile (MPN)-based liquid electrolyte that was solidified by a photochemically stable fluorine polymer, polyvinylidenefluoride-co-hexafluoropropylene (PVDF-HFP).
The use of the amphiphilic Z-907 dye in conjunction with the polymer gel electrolyte in DSC achieved an energy conversion efficiency of 6.1%. More importantly, the device was stable under thermal stress and soaking with light. The high conversion efficiency of the cell was sustained after heating for 1,000 h at 80 °C, maintaining 94% of its initial value. After
accelerated testing in a solar simulator for 1,000 h of light-soaking at 55 °C (100 mW cm) the efficiency had decreased by less than 5% for cells covered with an ultraviolet absorbing polymer film. These results are well within the limit for that of traditional inorganic silicon solar cells.
The enhanced performance may arise from a decrease in solvent permeation across the sealant due to the application of the polymer gel electrolyte. The polymer gel electrolyte is quasi-solid at room temperature, and becomes a viscous liquid (viscosity: 4.34 mPa·s) at 80 °C compared with the traditional liquid electrolyte (viscosity: 0.91 mPa·s). The much improved stabilities of the device under both thermal stress and soaking with light has never before been seen in DSCs, and they match the durability criteria applied to solar cells for outdoor use, which makes these devices viable for practical application. | 4 | Ultraviolet Radiation |
Small molecule inhibitors have been reported for both OGT and OGA that function in cells or in vivo. OGT inhibitors result in a global decrease of O-GlcNAc while OGA inhibitors result in a global increase of O-GlcNAc; these inhibitors are not able to modulate O-GlcNAc on specific proteins.
Inhibition of the hexosamine biosynthetic pathway is also able to decrease O-GlcNAc levels. For instance, glutamine analogues azaserine and 6-diazo-5-oxo-L-norleucine (DON) can inhibit GFAT, though these molecules may also non-specifically affect other pathways. | 2 | Carbohydrates |
* The general mathematical formalism used to describe and solve the Heisenberg model and certain generalizations is developed in the article on the Potts model.
* In the continuum limit the Heisenberg model (2) gives the following equation of motion
:This equation is called the continuous classical Heisenberg ferromagnet equation or shortly Heisenberg model and is integrable in the sense of soliton theory. It admits several integrable and nonintegrable generalizations like Landau-Lifshitz equation, Ishimori equation and so on. | 3 | Magnetic Ordering |
Very hot objects emit UV radiation (see black-body radiation). The Sun emits ultraviolet radiation at all wavelengths, including the extreme ultraviolet where it crosses into X-rays at 10 nm. Extremely hot stars (such as O- and B-type) emit proportionally more UV radiation than the Sun. Sunlight in space at the top of Earth's atmosphere (see solar constant) is composed of about 50% infrared light, 40% visible light, and 10% ultraviolet light, for a total intensity of about 1400 W/m in vacuum.
The atmosphere blocks about 77% of the Suns UV, when the Sun is highest in the sky (at zenith), with absorption increasing at shorter UV wavelengths. At ground level with the sun at zenith, sunlight is 44% visible light, 3% ultraviolet, and the remainder infrared. Of the ultraviolet radiation that reaches the Earths surface, more than 95% is the longer wavelengths of UVA, with the small remainder UVB. Almost no UVC reaches the Earth's surface. The fraction of UVA and UVB which remains in UV radiation after passing through the atmosphere is heavily dependent on cloud cover and atmospheric conditions. On "partly cloudy" days, patches of blue sky showing between clouds are also sources of (scattered) UVA and UVB, which are produced by Rayleigh scattering in the same way as the visible blue light from those parts of the sky. UVB also plays a major role in plant development, as it affects most of the plant hormones. During total overcast, the amount of absorption due to clouds is heavily dependent on the thickness of the clouds and latitude, with no clear measurements correlating specific thickness and absorption of UVA and UVB.
The shorter bands of UVC, as well as even more-energetic UV radiation produced by the Sun, are absorbed by oxygen and generate the ozone in the ozone layer when single oxygen atoms produced by UV photolysis of dioxygen react with more dioxygen. The ozone layer is especially important in blocking most UVB and the remaining part of UVC not already blocked by ordinary oxygen in air. | 4 | Ultraviolet Radiation |
Flow rate of the liquid phase and mole fraction of the desired compound in it are and .
Flow rate of the vapour phase and mole fraction of the desired compound in it are and . | 1 | Separation Processes |
Starch and amylopectin are often used in adhesive formulas, and are increasingly examined for further use in construction | 2 | Carbohydrates |
The level of nucleotides remaining in the cell after storage was thought by Warnick to be important in determining whether the cell would be able to re-synthesize ATP and recover after rewarming. Frequent changing of the perfusate or the use of a large volume of perfusate has the theoretical disadvantage that broken down adenine nucleotides may be washed out of the cells and so not be available for re-synthesis into ATP when the kidney is rewarmed. | 0 | Cryobiology |
Psychrophiles include bacteria, lichens, snow algae, phytoplankton, fungi, and insects.
Among the bacteria that can tolerate extreme cold are Arthrobacter sp., Psychrobacter sp. and members of the genera Halomonas, Pseudomonas, Hyphomonas, and Sphingomonas. Another example is Chryseobacterium greenlandensis, a psychrophile that was found in 120,000-year-old ice.
Umbilicaria antarctica and Xanthoria elegans are lichens that have been recorded photosynthesizing at temperatures ranging down to −24 °C, and they can grow down to around −10 °C. Some multicellular eukaryotes can also be metabolically active at sub-zero temperatures, such as some conifers; those in the Chironomidae family are still active at −16 °C.
Microalgae that live in snow and ice include green, brown, and red algae. Snow algae species such as Chloromonas sp., Chlamydomonas sp., and Chlorella sp. are found in polar environments.
Some phytoplankton can tolerate extremely cold temperatures and high salinities that occur in brine channels when sea ice forms in polar oceans. Some examples are diatoms like Fragilariopsis cylindrus, Nitzchia lecointeii, Entomoneis kjellmanii, Nitzchia stellata, Thalassiosira australis, Berkelaya adeliense, and Navicula glaciei.
Penicillium is a genus of fungi found in a wide range of environments including extreme cold.
Among the psychrophile insects, the Grylloblattidae or ice crawlers, found on mountaintops, have optimal temperatures between 1–4 °C. The wingless midge (Chironomidae) Belgica antarctica can tolerate salt, being frozen and strong ultraviolet, and has the smallest known genome of any insect. The small genome, of 99 million base pairs, is thought to be adaptive to extreme environments. | 0 | Cryobiology |