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Vogel was featured in the first episode of In Search Of... hosted by Leonard Nimoy, called "Other Voices". He gave his theories regarding the possibility of communication between plants. | 0 | Luminescence |
Some sperm banks enable recipients to choose the sex of their child, through methods of sperm sorting. Although the methods used do not guarantee 100% success, the chances of being able to select the gender of a child are held to be considerably increased.
One of the processes used is the swim up method, whereby a sperm extender is added to the donor's freshly ejaculated sperm and the test-tube is left to settle. After about half-an-hour, the lighter sperm, containing the male chromosome pair (XY), will have swum to the top, leaving the heavier sperm, containing the female chromosome pair (XX), at the bottom, thus allowing selection and storage according to sex.
The alternative process is the Percoll Method which is similar to the swim up method but involves additionally the centrifuging of the sperm in a similar way to the washing of samples produced for IUI inseminations, or for IVF purposes.
Sex selection is not permitted in a number of countries, including the UK. | 1 | Cryobiology |
* Tooth organoid (TO) (see also tooth regeneration)
* Thyroid organoid
* Thymic organoid
::Thymic organoids recapitulate at least partly the architecture and stem-cell niche functionality of the thymus, which is a lymphoid organ where T cells mature. Thymic organoids have been generated through the seeding of thymic stromal cells in 3-dimensional culture. Thymic organoids seem to successfully recapitulate the thymus' function, as co-culturing human hematopoietic or bone marrow stem cells with mouse thymic organoids resulted in the production of T-cells.
* Testicular organoid
*Prostate organoid
* Hepatic organoid. A recent study showed the usefulness of the technology for identifying novel medication for the treatment of hepatitis E as it allows to allows to recapitulate the entire viral life cycle.
* Pancreatic organoid
::Recent advances in cell repellent microtiter plates has allowed rapid, cost-effective screening of large small molecule drug like libraries against 3D models of pancreas cancer. These models are consistent in phenotype and expression profiles with those found in the lab of Dr. David Tuveson.
* Epithelial organoid
* Lung organoid
* Kidney organoid
* Gastruloid (embryonic organoid) – Generates all embryonic axes and fully implements the collinear Hox gene expression patterns along the anteroposterior axis.
* Blastoid (blastocyst-like organoid)
* Endometrial organoid
* Cardiac organoid – In 2018 hollow cardiac organoids were made to beat, and to respond to stimuli to beat faster or slower.
* Retinal organoid
* Breast cancer organoid
* Colorectal cancer organoid
* Glioblastoma organoid
* Neuroendocrine tumor organoid
* Myelinoid (Myelin organoid)
* Blood-brain barrier (BBB) organoid | 2 | Tissue Engineering |
In molecular biology and biochemistry, glycoconjugates are the classification family for carbohydrates – referred to as glycans – which are covalently linked with chemical species such as proteins, peptides, lipids, and other compounds. Glycoconjugates are formed in processes termed glycosylation.
Glycoconjugates are very important compounds in biology and consist of many different categories such as glycoproteins, glycopeptides, peptidoglycans, glycolipids, glycosides, and lipopolysaccharides. They are involved in cell–cell interactions, including cell–cell recognition; in cell–matrix interactions; in detoxification processes.
Generally, the carbohydrate part(s) play an integral role in the function of a glycoconjugate; prominent examples of this are neural cell adhesion molecule (NCAM) and blood proteins where fine details in the carbohydrate structure determine cell binding (or not) or lifetime in circulation.
Although the important molecular species DNA, RNA, ATP, cAMP, cGMP, NADH, NADPH, and coenzyme A all contain a carbohydrate part, generally they are not considered as glycoconjugates.
Glycocojugates of carbohydrates covalently linked to antigens and protein scaffolds can achieve a long term immunological response in the body. Immunization with glycoconjugates successfully induced long term immune memory against carbohydrates antigens. Glycoconjugate vaccines was introduced since the 1990s have yielded effective results against influenza and meningococcus.
In 2021 glycoRNAs were observed for the first time. | 6 | Carbohydrates |
Reverse osmosis is a more economical way to concentrate liquids (such as fruit juices) than conventional heat-treatment. Concentration of orange and tomato juice has advantages including a lower operating cost and the ability to avoid heat-treatment, which makes it suitable for heat-sensitive substances such as protein and enzymes.
RO is used in the dairy industry to produce whey protein powders and concentrate milk. The whey (liquid remaining after cheese manufacture) is concentrated with RO from 6% solids to 10–20% solids before ultrafiltration processing. The retentate can then be used to make whey powders, including whey protein isolate. Additionally, the permeate, which contains lactose, is concentrated by RO from 5% solids to 18–total solids to reduce crystallization and drying costs.
Although RO was once avoided in the wine industry, it is now widespread. An estimated 60 RO machines were in use in Bordeaux, France, in 2002. Known users include many of elite firms, such as Château Léoville-Las Cases. | 5 | Separation Processes |
In April 2014, a team of scientists led by Anthony Atala reported that they had successfully transplanted laboratory-grown vaginas into four female teenaged girls with a rare medical condition called Mayer-Rokitansky-Küster-Hauser syndrome that causes the vagina to develop improperly, or sometimes not at all. Between 1 of 1,500 to 4,000 females are born with this condition.
The four patients began treatment between May 2005 and August 2008. In each case, the medical research team began by taking a small sample of genital tissue from the teenagers vulva. The sample was used as a seed to grow additional tissue in the lab which was then placed in a vaginal shaped, biodegradable mold. Vaginal-lining cells were placed on the inside of the tube, while muscle cells were attached to the outside. Five to six weeks later, the structure was implanted into the patients, where the tissue continued to grow and connected with the girls circulatory and other bodily systems. After about eight years, all four patients reported normal function and pleasure levels during sexual intercourse according to the Female Sexual Function Index questionnaire, a validated self-report tool. No adverse results or complications were reported.
In two of the four women, the vagina was attached to the uterus, making pregnancy possible. No pregnancies were reported, however, during the study period. Martin Birchall, who works on tissue engineering, but was not involved in the study, said it "addressed some of the most important questions facing translation of tissue engineering technologies." Commentary published by the National Health Service (NHS) called the study "an important proof of concept" and said it showed that tissue engineering had "a great deal of potential." However, the NHS also cautioned that the sample size was very small and further research was necessary to determine the general viability of the technique.
The laboratory-grown autologous transplant technique could also be used on women who want reconstructive surgery due to cancer or other disease once the technique is perfected. However, more studies will need to be conducted and the techniques further developed before commercial production can begin. | 2 | Tissue Engineering |
EFDA (1999 — 2013) has been followed by EUROfusion, which is a consortium of national fusion research institutes located in the European Union and Switzerland.
The European Union has a strongly coordinated nuclear fusion research programme. At the European level, the so-called [http://europa.eu/legislation_summaries/institutional_affairs/treaties/treaties_euratom_en.htm EURATOM Treaty] is the international legal framework under which member states cooperate in the fields of nuclear fusion research.
The [https://web.archive.org/web/20140914125632/http://www.efda.org/ European Fusion Development Agreement] (EFDA) is an agreement between European fusion research institutions and the European Commission (which represents Euratom) to strengthen their coordination and collaboration, and to participate in collective activities in the field of nuclear fusion research.
In Europe, fusion research takes place in a great number of research institutes and universities. In each member state of the European Fusion Programme at least one research organisation has a "Contract of Association" with the European Commission. All the fusion research organisations and institutions of a country are connected to the program through this (these) contracted organisation(s). After the name of the contract, the groups of fusion research organisations of the member states are called "Associations". | 3 | Nuclear Fusion |
The alpha process, also known as alpha capture or the alpha ladder, is one of two classes of nuclear fusion reactions by which stars convert helium into heavier elements. The other class is a cycle of reactions called the triple-alpha process, which consumes only helium, and produces carbon. The alpha process most commonly occurs in massive stars and during supernovae.
Both processes are preceded by hydrogen fusion, which produces the helium that fuels both the triple-alpha process and the alpha ladder processes. After the triple-alpha process has produced enough carbon, the alpha-ladder begins and fusion reactions of increasingly heavy elements take place, in the order listed below. Each step only consumes the product of the previous reaction and helium. The later-stage reactions which are able to begin in any particular star, do so while the prior stage reactions are still under way in outer layers of the star.
The energy produced by each reaction, , is mainly in the form of gamma rays (), with a small amount taken by the byproduct element, as added momentum.
It is a common misconception that the above sequence ends at (or , which is a decay product of ) because it is the most tightly bound nuclide – i.e., the nuclide with the highest nuclear binding energy per nucleon – and production of heavier nuclei would consume energy (be endothermic) instead of release it (exothermic). (Nickel-62) is actually the most tightly bound nuclide in terms of binding energy (though has a lower energy or mass per nucleon). The reaction is actually exothermic, and indeed adding alphas continues to be exothermic all the way to , but nonetheless the sequence does effectively end at iron. The sequence stops before producing because conditions in stellar interiors cause the competition between photodisintegration and the alpha process to favor photodisintegration around iron. This leads to more being produced than
All these reactions have a very low rate at the temperatures and densities in stars and therefore do not contribute significant energy to a star's total output. They occur even less easily with elements heavier than neon due to the increasing Coulomb barrier. | 3 | Nuclear Fusion |
Acid attacks are common in Vietnam. Most victims are female. While the issue in other Asian countries like Cambodia, India and Pakistan is constantly monitored by domestic and transnational organizations, the situation in Vietnam is rather off the radar. Official statistics on acid attacks in the country are hard to record. Most of Vietnam's acid attack victims spend their lives isolated and ignored and also blamed for their condition. Kevin Hawkins, an American lawyer working for Vietnam-based VILAF law firm, notes the alarming prevalence of using acid in attacks, mostly for revenge and particularly in relation to failed romantic relationships or pursuits. The current Vietnamese penal code stipulates that those who use acid to attack their victims face a charge of “intentionally injuring others,” rather than “murder,” which thus fails to discourage potential offenders. | 4 | Acids + Bases |
In 1946, some maple syrup producers started using RO to remove water from sap before boiling the sap to syrup. RO allows about 75–90% of the water to be removed, reducing energy consumption and exposure of the syrup to high temperatures. | 5 | Separation Processes |
* Stilbene will typically have the chemistry of a diarylethene, a conjugated alkene.
* Stilbene can undergo photoisomerization under the influence of UV light.
* Stilbene can undergo stilbene photocyclization, an intramolecular reaction.
* (Z)-Stilbene can undergo electrocyclic reactions. | 0 | Luminescence |
In 1960 John Nuckolls published the concept of inertial confinement fusion (ICF). The laser, introduced the same year, turned out to be a suitable "driver".
In 1961 the Soviet Union tested its 50 megaton Tsar Bomba, the most powerful thermonuclear weapon ever.
Spitzer published a key plasma physics text at Princeton in 1963. He took the ideal gas laws and adapted them to an ionized plasma, developing many of the fundamental equations used to model a plasma.
Laser fusion was suggested in 1962 by scientists at LLNL. Initially, lasers had little power. Laser fusion (inertial confinement fusion) research began as early as 1965.
At the 1964 World's Fair, the public was given its first fusion demonstration. The device was a Theta-pinch from General Electric. This was similar to the Scylla machine developed earlier at Los Alamos.
By the mid-1960s progress had stalled across the world. All of the major designs were losing plasma at unsustainable rates. The 12-beam "4 pi laser" attempt at inertial confinement fusion developed at LLNL targeted a gas-filled target chamber of about 20 centimeters in diameter.
The magnetic mirror was first published in 1967 by Richard F. Post and many others at LLNL. The mirror consisted of two large magnets arranged so they had strong fields within them, and a weaker, but connected, field between them. Plasma introduced in the area between the two magnets would "bounce back" from the stronger fields in the middle.
A.D. Sakharov's group constructed the first tokamaks. The most successful were the T-3 and its larger version T-4. T-4 was tested in 1968 in Novosibirsk, producing the first quasistationary fusion reaction. When this was announced, the international community was skeptical. A British team was invited to see T-3, and confirmed the Soviet claims. A burst of activity followed as many planned devices were abandoned and tokamaks were introduced in their place—the C model stellarator, then under construction after many redesigns, was quickly converted to the Symmetrical Tokamak.
In his work with vacuum tubes, Philo Farnsworth observed that electric charge accumulated in the tube. In 1962, Farnsworth patented a design using a positive inner cage to concentrate plasma and fuse protons. During this time, Robert L. Hirsch joined Farnsworth Television labs and began work on what became the Farnsworth-Hirsch Fusor. This effect became known as the Multipactor effect. Hirsch patented the design in 1966 and published it in 1967.
Plasma temperatures of approximately 40 million degrees Celsius and 10 deuteron-deuteron fusion reactions per discharge were achieved at LANL with Scylla IV.
In 1968 the Soviets announced results from the T-3 tokamak, claiming temperatures an order of magnitude higher than any other device. A UK team, nicknamed "The Culham Five", confirmed the results. The results led many other teams, including the Princeton group, which converted their stellarator to a tokamak. | 3 | Nuclear Fusion |
Polyols are found naturally in mushrooms, some fruit (particularly stone fruits), including apples, apricots, avocados, blackberries, cherries, lychees, nectarines, peaches, pears, plums, prunes, watermelon, and in some vegetables, including cauliflower, snow peas, and mange-tout peas. Cabbage, chicory, and fennel contain moderate amounts, but may be eaten in a low-FODMAP diet if the advised portion size is observed.
Polyols, specifically sugar alcohols, used as artificial sweeteners in commercially prepared food, beverages, and chewing gum, include isomalt, maltitol, mannitol, sorbitol, and xylitol. | 6 | Carbohydrates |
Luminescence in a semiconductor results when an electron in the conduction band recombines with a hole in the valence band. The difference energy (band gap) of this transition can be emitted in form of a photon. The energy (color) of the photon, and the probability that a photon and not a phonon will be emitted, depends on the material, its purity, and the presence of defects. First, the electron has to be excited from the valence band into the conduction band. In cathodoluminescence, this occurs as the result of an impinging high energy electron beam onto a semiconductor. However, these primary electrons carry far too much energy to directly excite electrons. Instead, the inelastic scattering of the primary electrons in the crystal leads to the emission of secondary electrons, Auger electrons and X-rays, which in turn can scatter as well. Such a cascade of scattering events leads to up to 10 secondary electrons per incident electron. These secondary electrons can excite valence electrons into the conduction band when they have a kinetic energy about three times the band gap energy of the material . From there the electron recombines with a hole in the valence band and creates a photon. The excess energy is transferred to phonons and thus heats the lattice. One of the advantages of excitation with an electron beam is that the band gap energy of materials that are investigated is not limited by the energy of the incident light as in the case of photoluminescence. Therefore, in cathodoluminescence, the "semiconductor" examined can, in fact, be almost any non-metallic material. In terms of band structure, classical semiconductors, insulators, ceramics, gemstones, minerals, and glasses can be treated the same way. | 0 | Luminescence |
Strontium aluminates are considered non-toxic, and are biologically and chemically inert.
Care should be used when handling loose powder, which can cause irritation if inhaled or exposed to mucous membranes. | 0 | Luminescence |
A detailed account of the history of spin glasses from the early 1960s to the late 1980s can be found in a series of popular articles by Philip W. Anderson in Physics Today. | 7 | Magnetic Ordering |
Chloroauric acid is the precursor used in the purification of gold by electrolysis.
Liquid–liquid extraction of chloroauric acid is used for the recovery, concentrating, purification, and analytical determinations of gold. Of great importance is the extraction of from hydrochloric medium by oxygen-containing extractants, such as alcohols, ketones, ethers and esters. The concentration of gold(III) in the extracts may exceed 1 mol/L. Frequently used extractants for this purpose are dibutyl glycol, methyl isobutyl ketone, tributyl phosphate, dichlorodiethyl ether (chlorex).
In histology, chlorauric acid is known as "brown gold chloride", and its sodium salt (sodium tetrachloroaurate(III)) as "gold chloride", "sodium gold chloride" or "yellow gold chloride". The sodium salt is used in a process called "toning" to improve the optical definition of tissue sections stained with silver. | 4 | Acids + Bases |
One study conducted by investigators at the University of North Carolina Chapel Hill looked into donated sperm utilization within the United States from 1995 to 2017. Cross-sectional studies recorded that an estimated 170,701 individuals during 1995 used donated sperm, while the 2011 to 2013 cohort had a decreased amount of donated sperm use of 37,385. Most recently, in the 2015 to 2017 cohort, 440,986 individuals were reported to use donated sperm. When looking at 200,197 individuals across 2011–2017, 76% had a 4-year college degree or further while 24% had high school or 2-year college degree. In terms of household percent of poverty, 71% of the sperm bank users were at or above 400% of the household poverty level while only 11% were between 200 and 399% of the household poverty levels. Although the household income levels were not explicit, there seems to be an obvious trend that higher education level attainment (such as finishing college or higher) and being at much higher income level above the household poverty levels were the common tendencies in the sperm bank users. | 1 | Cryobiology |
At the beginning of the Society, it was agreed that there would be Continental Chapters of TERMIS, initially TERMIS-North America (TERMIS-NA) and TERMIS-Europe (TERMIS-EU), to be joined at the time of the major Shanghai conference in October 2005 by TERMIS-Asia Pacific (TERMIS-AP). It was subsequently agreed that the remit of TERMIS-North America should be expanded to incorporate activity in South America, the chapter becoming TERMIS-Americas (TERMS-AM) officially in 2012. | 2 | Tissue Engineering |
In naphtha cracking process, C4R2 refers to C4 residual obtained after separation of 1,3-butadiene and isobutylene from C4 raffinate stream and which mainly consists of cis- or trans-2-butene 50~60 wt%, 1-butene 10~15 wt%, and n-butane ~20 wt%. Normally C4R2 is a side product in tert-butyl alcohol plant if C4R1 is used for feed. | 5 | Separation Processes |
During the more than 80 years of technical development of sensor-based ore sorting equipment, various types of machines have been developed. This includes the channel-type, bucket-wheel type and cone type sorters. The main machine types being installed in the mining industry today are belt-type and chute-type machines. Harbeck made a good comparison of both disadvantages and advantages of the systems for different sorting applications. The selection of a machine-type for an application depends various case-dependent factors, including the detection system applied, particle size, moisture, yield amongst others. | 5 | Separation Processes |
Eletrospraying is used to create alginate spheres by pumping an alginate solution through a needle. A source of high voltage usually provided by a clamp attached to the needle is used to generate an electric potential with the alginate falling from the needle tip into a solution that contains a ground. Calcium chloride is used as cross linking solution in which the generated capsules drop into where they harden after approximately 30 minutes. Beads are formed from the needle due to charge and surface tension.
* Size dependency of the beads
** height alterations of device from needle to calcium chloride solution
** voltage alterations of clamp on the needle
** alginate concentration alterations | 2 | Tissue Engineering |
Lactulose is a disaccharide formed from one molecule each of the simple sugars (monosaccharides) fructose and galactose. Lactulose is not normally present in raw milk, but is a product of heat processes: the greater the heat, the greater amount of this substance (from 3.5 mg/L in low-temperature pasteurized milk to 744 mg/L in in-container sterilized milk).
Lactulose is produced commercially by isomerization of lactose. A variety of reaction conditions and catalysts can be used. | 6 | Carbohydrates |
Machine perfusion (MP) is a technique used in organ transplantation as a means of preserving the organs which are to be transplanted.
Machine perfusion has various forms and can be categorised according to the temperature of the perfusate: cold (4 °C) and warm (37 °C). Machine perfusion has been applied to renal transplantation, liver transplantation and lung transplantation. It is an alternative to static cold storage (SCS). | 1 | Cryobiology |
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). | 5 | Separation Processes |
Trehalose (from Turkish tıgala – a sugar derived from insect cocoons + -ose) is a sugar consisting of two molecules of glucose. It is also known as mycose or tremalose. Some bacteria, fungi, plants and invertebrate animals synthesize it as a source of energy, and to survive freezing and lack of water.
Extracting trehalose was once a difficult and costly process, but around 2000, the Hayashibara company (Okayama, Japan) discovered an inexpensive extraction technology from starch. Trehalose has high water retention capabilities, and is used in food, cosmetics and as a drug. A procedure developed in 2017 using trehalose allows sperm storage at room temperatures. | 6 | Carbohydrates |
, where is the enthalpy of the liquid and is the enthalpy of the vapour
By substituting the mass balance equation in above equation we get the following expression: | 5 | Separation Processes |
In scientific literature, the term "carbohydrate" has many synonyms, like "sugar" (in the broad sense), "saccharide", "ose", "glucide", "hydrate of carbon" or "polyhydroxy compounds with aldehyde or ketone". Some of these terms, especially "carbohydrate" and "sugar", are also used with other meanings.
In food science and in many informal contexts, the term "carbohydrate" often means any food that is particularly rich in the complex carbohydrate starch (such as cereals, bread and pasta) or simple carbohydrates, such as sugar (found in candy, jams, and desserts). This informality is sometimes confusing since it confounds chemical structure and digestibility in humans.
Often in lists of nutritional information, such as the USDA National Nutrient Database, the term "carbohydrate" (or "carbohydrate by difference") is used for everything other than water, protein, fat, ash, and ethanol. This includes chemical compounds such as acetic or lactic acid, which are not normally considered carbohydrates. It also includes dietary fiber which is a carbohydrate but which does not contribute food energy in humans, even though it is often included in the calculation of total food energy just as though it did (i.e., as if it were a digestible and absorbable carbohydrate such as a sugar).
In the strict sense, "sugar" is applied for sweet, soluble carbohydrates, many of which are used in human food. | 6 | Carbohydrates |
Pure organochlorides like polyvinyl chloride (PVC) do not absorb any light above 220 nm. The initiation of photo-oxidation is instead caused by various irregularities in the polymer chain, such as structural defects as well as hydroperoxides, carbonyl groups, and double bonds.
Hydroperoxides formed during processing are the most important initiator to begin with, however their concentration decreases during photo-oxidation whereas carbonyl concentration increases, as such carbonyls may become the primary initiator over time.
Propagation steps involve the hydroperoxyl radical, which can abstract hydrogen from both hydrocarbon (-CH-) and organochloride (-CHCl-) sites in the polymer at comparable rates. Radicals formed at hydrocarbon sites rapidly convert to alkenes with loss of radical chlorine. This forms allylic hydrogens (shown in red) which are more susceptible to hydrogen abstraction leading to the formation of polyenes in zipper-like reactions.
When the polyenes contain at least eight conjugated double bonds they become coloured, leading to yellowing and eventual browning of the material. This is off-set slightly by longer polyenes being photobleached with atmospheric oxygen, however PVC does eventually discolour unless polymer stabilisers are present. Reactions at organochloride sites proceed via the usual hydroperoxyl and hydroperoxide before photolysis yields the α-chloro-alkoxyl radical. This species can undergo various reactions to give carbonyls, peroxide cross-links and beta scission products. | 8 | Ultraviolet Radiation |
The fluorophore absorbs light energy of a specific wavelength and re-emits light at a longer wavelength. The absorbed wavelengths, energy transfer efficiency, and time before emission depend on both the fluorophore structure and its chemical environment, since the molecule in its excited state interacts with surrounding molecules. Wavelengths of maximum absorption (≈ excitation) and emission (for example, Absorption/Emission = 485 nm/517 nm) are the typical terms used to refer to a given fluorophore, but the whole spectrum may be important to consider. The excitation wavelength spectrum may be a very narrow or broader band, or it may be all beyond a cutoff level. The emission spectrum is usually sharper than the excitation spectrum, and it is of a longer wavelength and correspondingly lower energy. Excitation energies range from ultraviolet through the visible spectrum, and emission energies may continue from visible light into the near infrared region.
The main characteristics of fluorophores are:
* Maximum excitation and emission wavelength (expressed in nanometers (nm)): corresponds to the peak in the excitation and emission spectra (usually one peak each).
* Molar absorption coefficient (in molcm): links the quantity of absorbed light, at a given wavelength, to the concentration of fluorophore in solution.
* Quantum yield: efficiency of the energy transferred from incident light to emitted fluorescence (the number of emitted photons per absorbed photons).
* Lifetime (in picoseconds): duration of the excited state of a fluorophore before returning to its ground state. It refers to the time taken for a population of excited fluorophores to decay to 1/e (≈0.368) of the original amount.
* Stokes shift: the difference between the maximum excitation and maximum emission wavelengths.
* Dark fraction: the proportion of the molecules not active in fluorescence emission. For quantum dots, prolonged single-molecule microscopy showed that 20-90% of all particles never emit fluorescence. On the other hand, conjugated polymer nanoparticles (Pdots) show almost no dark fraction in their fluorescence. Fluorescent proteins can have a dark fraction from protein misfolding or defective chromophore formation.
These characteristics drive other properties, including photobleaching or photoresistance (loss of fluorescence upon continuous light excitation). Other parameters should be considered, as the polarity of the fluorophore molecule, the fluorophore size and shape (i.e. for polarization fluorescence pattern), and other factors can change the behavior of fluorophores.
Fluorophores can also be used to quench the fluorescence of other fluorescent dyes or to relay their fluorescence at even longer wavelengths. | 0 | Luminescence |
Peptide therapeutics such as are attractive for their high specificity and potency, but they often have poor pharmacokinetic profiles due to their degradation by serum proteases. Though O-GlcNAc is generally associated with intracellular proteins, it has been found that engineered peptide therapeutics modified by O-GlcNAc have enhanced serum stability in a mouse model and have similar structure and activity compared to the respective unmodified peptides. This method has been applied to engineer GLP-1 and PTH peptides. | 6 | Carbohydrates |
Ignition should not be confused with breakeven, a similar concept that compares the total energy being given off to the energy being used to heat the fuel. The key difference is that breakeven ignores losses to the surroundings, which do not contribute to heating the fuel, and thus are not able to make the reaction self-sustaining. Breakeven is an important goal in the fusion energy field, but ignition is required for a practical energy producing design.
In nature, stars reach ignition at temperatures similar to that of the Sun, around 15 million kelvins (27 million degrees F). Stars are so large that the fusion products will almost always interact with the plasma before their energy can be lost to the environment at the outside of the star. In comparison, man-made reactors are far less dense and much smaller, allowing the fusion products to easily escape the fuel. To offset this, much higher rates of fusion are required, and thus much higher temperatures; most man-made fusion reactors are designed to work at temperatures over 100 million kelvins (180 million degrees F).
Fusion ignition was first achieved by humans in the cores of detonating thermonuclear weapons. A thermonuclear weapon uses a conventional fission (U-235 or Pu-239/241) "sparkplug" to generate high pressures and compress a rod of fusion fuel (usually lithium deuteride). The fuel reaches high enough pressures and densities to ignite, releasing large amounts of energy and neutrons in the process.
The National Ignition Facility at Lawrence Livermore National Laboratory performs laser-driven inertial confinement fusion experiments that achieve fusion ignition. This is similar to a thermonuclear weapon, but the National Ignition Facility uses a 1.8 MJ laser system instead of a fission weapon to compress the fuel, and uses a much smaller amount of fuel (a mixture of deuterium and tritium, which are both isotopes of hydrogen).
In January 2012, National Ignition Facility Director Mike Dunne predicted in a Photonics West 2012 plenary talk that ignition would be achieved at NIF by October 2012.
By 2022 the NIF had achieved ignition.
Based on the tokamak reactor design, the ITER is intended to sustain fusion mostly by internal fusion heating and yield in its plasma a ten-fold return on power. Construction is expected to be completed in 2025.
Experts believe that achieving fusion ignition is the first step towards electricity generation using fusion power. | 3 | Nuclear Fusion |
An example that illustrates nuclear binding energy is the nucleus of C (carbon-12), which contains 6 protons and 6 neutrons. The protons are all positively charged and repel each other, but the nuclear force overcomes the repulsion and causes them to stick together. The nuclear force is a close-range force (it is strongly attractive at a distance of 1.0 fm and becomes extremely small beyond a distance of 2.5 fm), and virtually no effect of this force is observed outside the nucleus. The nuclear force also pulls neutrons together, or neutrons and protons.
The energy of the nucleus is negative with regard to the energy of the particles pulled apart to infinite distance (just like the gravitational energy of planets of the Solar System), because energy must be utilized to split a nucleus into its individual protons and neutrons. Mass spectrometers have measured the masses of nuclei, which are always less than the sum of the masses of protons and neutrons that form them, and the difference—by the formula —gives the binding energy of the nucleus. | 3 | Nuclear Fusion |
Pregnancy rate may be defined in various ways. In the United States, SART and the Centers for Disease Control (and appearing in the table in the Success Rates section above) include statistics on positive pregnancy test and clinical pregnancy rate.
The 2019 summary compiled by the SART the following data for non-donor eggs (first embryo transfer) in the United States:
In 2006, Canadian clinics reported an average pregnancy rate of 35%. A French study estimated that 66% of patients starting IVF treatment finally succeed in having a child (40% during the IVF treatment at the centre and 26% after IVF discontinuation). Achievement of having a child after IVF discontinuation was mainly due to adoption (46%) or spontaneous pregnancy (42%). | 1 | Cryobiology |
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. | 5 | Separation Processes |
In chemistry, recrystallization is a procedure for purifying compounds. The most typical situation is that a desired "compound A" is contaminated by a small amount of "impurity B". There are various methods of purification that may be attempted (see Separation process), recrystallization being one of them. There are also different recrystallization techniques that can be used such as: | 5 | Separation Processes |
Microscopic algae that can tolerate extremely cold temperatures can survive in snow, ice, and very cold seawater. On snow, cold-tolerant algae can bloom on the snow surface covering land, glaciers, or sea ice when there is sufficient light. These snow algae darken the surface of the snow and can contribute to snow melt. In seawater, phytoplankton that can tolerate both very high salinities and very cold temperatures are able to live in sea ice. One example of a psychrophilic phytoplankton species is the ice-associated diatom Fragilariopsis cylindrus. Phytoplankton living in the cold ocean waters near Antarctica often have very high protein content, containing some of the highest concentrations ever measured of enzymes like Rubisco. | 1 | Cryobiology |
In a ferromagnet, the magnitude of the magnetization at each spacetime point is approximated by the saturation magnetization (although it can be smaller when averaged over a chunk of volume). The Landau-Lifshitz equation, a precursor of the LLG equation, phenomenologically describes the rotation of the magnetization in response to the effective field which accounts for not only a real magnetic field but also internal magnetic interactions such as exchange and anisotropy. An earlier, but equivalent, equation (the Landau–Lifshitz equation) was introduced by :
where is the electron gyromagnetic ratio and is a phenomenological damping parameter, often replaced by
where is a dimensionless constant called the damping factor. The effective field is a combination of the external magnetic field, the demagnetizing field, and various internal magnetic interactions involving quantum mechanical effects, which is typically defined as the functional derivative of the magnetic free energy with respect to the local magnetization . To solve this equation, additional conditions for the demagnetizing field must be included to accommodate the geometry of the material. | 7 | Magnetic Ordering |
Cold-adapted arctic frogs, such as wood frogs, and some other ectotherms in polar and subpolar regions naturally produce glucose, but southern brown tree frogs and Arctic salamanders create glycerol in their livers to reduce ice formation.
When glucose is used as a cryoprotectant by arctic frogs, massive amounts of glucose are released at low temperature and a special form of insulin allows for this extra glucose to enter the cells. When the frog rewarms during spring, the extra glucose must be rapidly eliminated, but stored. | 1 | Cryobiology |
Ions can be created by electrons formed in high-frequency electromagnetic field. The discharge is formed in a tube located between electrodes, or inside a coil. Over 90% proportion of atomic ions is achievable. | 3 | Nuclear Fusion |
Transportable semi-mobile installations have gained increasing popularity in the last two decades. They are enabled by the fact that complete sensor-based sorting systems are relatively compact in relation to the capacity in tonnes per hour. This is mainly because little infrastructure is needed. The picture shows a containerised sensor-based sorter which is applied in Chromitite sorting. The system is operated in conjunction with a Diesel-powered mobile crusher and screen. Material handling of the feed, undersize fraction, product and waste fraction is conducted using a wheel loader. The system is powered by a Diesel generator and a compressor station delivers the instrument quality air needed for the operation.
Semi-mobile installations are applied primarily to minimise material handling and save transport costs. Another reason for choosing the semi-mobile option for an installation is bulk testing of new ore bodies. Capacity of a system very much depends on the size fraction sorted, but a 250tph capacity is a good estimate for semi-mobile installations, considering a capacity of 125tph sorter feed and 125tph undersize material. During the last decade both generic plant designs and customised designs have been developed, for example in the framework of the i2mine project. | 5 | Separation Processes |
Trehalose is a disaccharide formed by a bond between two α-glucose units. It is found in nature as a disaccharide and also as a monomer in some polymers. Two other isomers exist, α,β-trehalose, otherwise known as neotrehalose, and β,β-trehalose (also referred to as isotrehalose). Neotrehalose has not been isolated from a living organism. Isotrehalose is also yet to be isolated from a living organism, but was found in starch hydroisolates. | 6 | Carbohydrates |
Besides being a source of energy, few other functions have been described for galactogen in the snail eggs, and all of them are related to embryo defense and protection. Given that carbohydrates retain water, the high amount of this polysaccharide would protect the eggs from desiccation from those snails that have aerial oviposition. Besides, the high viscosity that the polysaccharide may confer to the perivitelline fluid has been suggested as a potential antimicrobial defense.
Since galactogen is a β-linked polysaccharide, such as cellulose or hemicelluloses, specific biochemical adaptations are needed to exploit it as a nutrient, such as specific glycosidases. However, apart from snail embryos and hatchlings, no animal seems to be able to catabolize galactogen, including adult snails. This fact led to consider galactogen as part of an antipredation defense system exclusive of gastropods, deterring predators by lowering the nutritional value of eggs. | 6 | Carbohydrates |
In atherosclerosis, a severe disease in modern society, coronary blood vessels occlude. These vessels have to be freed and held open i.e. by stents. Unfortunately after certain time these vessels close again and have to be bypassed to allow for upkeep of circulation. Usually autologous vessels from the patient or synthetic polymer grafts are used for this purpose. Both options have disadvantages. Firstly there are only few autologous vessels available in a human body that might be of low quality, considering the health status of the patient. The synthetic polymer based grafts on the other hand often have insufficient haemocompatibility and thus rapidly occlude - a problem that is especially prone in small calibre grafts. In this context the fibrin-gel-based tissue engineering of autologous vessel substitutes is a very promising approach to overcome the current problems. Cells and fibrin are isolated by a low invasive procedure from the patient and shaped in individual moulds to meet the required dimensions. Additional pre-cultivation in a specialized bioreactor is inevitable to ensure appropriate properties of the graft. | 2 | Tissue Engineering |
Luminescence is the "spontaneous emission of radiation from an electronically excited species (or from a vibrationally excited species) not in thermal equilibrium with its environment", according to the IUPAC definition. A luminescent object is emitting "cold light", in contrast to "incandescence", where an object only emits light after heating. Generally, the emission of light is due to the movement of electrons between different energy levels within an atom after excitation by external factors. However, the exact mechanism of light emission in "vibrationally excited species" is unknown, as seen in sonoluminescence.
The dials, hands, scales, and signs of aviation and navigational instruments and markings are often coated with luminescent materials in a process known as "luminising". | 0 | Luminescence |
Fluorescent paints glow when exposed to short-wave ultraviolet (UV) radiation. These UV wavelengths are found in sunlight and many artificial lights, but the paint requires a special black light to view so these glowing-paint applications are called black-light effects. Fluorescent paint is available in a wide range of colors and is used in theatrical lighting and effects, posters, and as entertainment for children.
The fluorescent chemicals in fluorescent paint absorb the invisible UV radiation, then emit the energy as longer wavelength visible light of a particular color. Human eyes perceive this light as the unusual glow of fluorescence. The painted surface also reflects any ordinary visible light striking it, which tends to wash out the dim fluorescent glow. So viewing fluorescent paint requires a longwave UV light which does not emit much visible light. This is called a black light. It has a dark blue filter material on the bulb which lets the invisible UV pass but blocks the visible light the bulb produces, allowing only a little purple light through. Fluorescent paints are best viewed in a darkened room.
Fluorescent paints are made in both visible and invisible types. Visible fluorescent paint also has ordinary visible light pigments, so under white light it appears a particular color, and the color just appears enhanced brilliantly under black lights. Invisible fluorescent paints appear transparent or pale under daytime lighting, but will glow under UV light. Since patterns painted with this type are invisible under ordinary visible light, they can be used to create a variety of clever effects.
Both types of fluorescent painting benefit when used within a contrasting ambiance of clean, matte-black backgrounds and borders. Such a "black out" effect will minimize other awareness, so cultivating the peculiar luminescence of UV fluorescence. Both types of paints have extensive application where artistic lighting effects are desired, particularly in "black box" entertainments and environments such as theaters, bars, shrines, etc. The effective wattage needed to light larger empty spaces increases, with narrow-band light such as UV wavelengths being rapidly scattered in outdoor environments. | 0 | Luminescence |
The Human Tissue (Scotland) Act 2006 (asp 4) is an Act of the Scottish Parliament to consolidate and overhaul previous legislation regarding the handling of human tissue.
It deals with three distinct uses of human tissue: its donation primarily for the purpose of transplantation, but also for research, education or training and audit; its removal, retention and use following a post-mortem examination; and for the purposes of the Anatomy Act 1984 as amended for Scotland by the 2006 Act.
Its counterpart in the rest of the United Kingdom is the Human Tissue Act 2004. | 2 | Tissue Engineering |
Viaspan was the trademark under which the University of Wisconsin cold storage solution (also known as University of Wisconsin solution or UW solution) was sold. Currently, UW solution is sold under the Belzer UW trademark and others like Bel-Gen or StoreProtect. UW solution was the first solution designed for use in organ transplantation, and became the first intracellular-like preservation medium. Developed in the late 1980s by Folkert Belzer and James Southard for pancreas preservation, the solution soon displaced EuroCollins solution as the preferred medium for cold storage of livers and kidneys, as well as pancreas. The solution has also been used for hearts and other organs. University of Wisconsin cold storage solution remains what is often called the gold standard for organ preservation, despite the development of other solutions that are in some respects superior. | 1 | Cryobiology |
Ferrimagnetic materials have high resistivity and have anisotropic properties. The anisotropy is actually induced by an external applied field. When this applied field aligns with the magnetic dipoles, it causes a net magnetic dipole moment and causes the magnetic dipoles to precess at a frequency controlled by the applied field, called Larmor or precession frequency. As a particular example, a microwave signal circularly polarized in the same direction as this precession strongly interacts with the magnetic dipole moments; when it is polarized in the opposite direction, the interaction is very low. When the interaction is strong, the microwave signal can pass through the material. This directional property is used in the construction of microwave devices like isolators, circulators, and gyrators. Ferrimagnetic materials are also used to produce optical isolators and circulators. Ferrimagnetic minerals in various rock types are used to study ancient geomagnetic properties of Earth and other planets. That field of study is known as paleomagnetism. In addition, it has been shown that ferrimagnets such as magnetite can be used for thermal energy storage. | 7 | Magnetic Ordering |
Plants in temperate and polar regions adapt to winter and sub zero temperatures by relocating nutrients from leaves and shoots to storage organs. Freezing temperatures induce dehydrative stress on plants, as water absorption in the root and water transport in the plant decreases. Water in and between cells in the plant freezes and expands, causing tissue damage. Cold hardening is a process in which a plant undergoes physiological changes to avoid, or mitigate cellular injuries caused by sub-zero temperatures. Non-acclimatized individuals can survive −5 °C, while an acclimatized individual in the same species can survive −30 °C. Plants that originated in the tropics, like tomato or maize, don't go through cold hardening and are unable to survive freezing temperatures. The plant starts the adaptation by exposure to cold yet still not freezing temperatures. The process can be divided into three steps. First the plant perceives low temperature, then converts the signal to activate or repress expression of appropriate genes. Finally, it uses these genes to combat the stress, caused by sub-zero temperatures, affecting its living cells. Many of the genes and responses to low temperature stress are shared with other abiotic stresses, like drought or salinity.
When temperature drops, the membrane fluidity, RNA and DNA stability, and enzyme activity change. These, in turn, affect transcription, translation, intermediate metabolism, and photosynthesis, leading to an energy imbalance. This energy imbalance is thought to be one of the ways the plant detects low temperature. Experiments on arabidopsis show that the plant detects the change in temperature, rather than the absolute temperature. The rate of temperature drop is directly connected to the magnitude of calcium influx, from the space between cells, into the cell. Calcium channels in the cell membrane detect the temperature drop, and promotes expression of low temperature responsible genes in alfalfa and arabidopsis. The response to the change in calcium elevation depends on the cell type and stress history. Shoot tissue will respond more than root cells, and a cell that already is adapted to cold stress will respond more than one that has not been through cold hardening before. Light doesn't control the onset of cold hardening directly, but shortening of daylight is associated with fall, and starts production of reactive oxygen species and excitation of photosystem 2, which influences low-temp signal transduction mechanisms. Plants with compromised perception of day length have compromised cold acclimation.
Cold increases cell membrane permeability and makes the cell shrink, as water is drawn out when ice is formed in the extracellular matrix between cells. To retain the surface area of the cell membrane so it will be able to regain its former volume when temperature rises again, the plant forms more and stronger Hechtian strands. These are tubelike structures that connect the protoplast with the cell wall. When the intracellular water freezes, the cell will expand, and without cold hardening the cell would rupture. To protect the cell membrane from expansion induced damage, the plant cell changes the proportions of almost all lipids in the cell membrane, and increases the amount of total soluble protein and other cryoprotecting molecules, like sugar and proline.
Chilling injury occurs at 0–10 degrees Celsius, as a result of membrane damage, metabolic changes, and toxic buildup. Symptoms include wilting, water soaking, necrosis, chlorosis, ion leakage, and decreased growth. Freezing injury may occur at temperatures below 0 degrees Celsius. Symptoms of extracellular freezing include structural damage, dehydration, and necrosis. If intracellular freezing occurs, it will lead to death. Freezing injury is a result of lost permeability, plasmolysis, and post-thaw cell bursting.
When spring comes, or during a mild spell in winter, plants de-harden, and if the temperature is warm for long enough – their growth resumes. | 1 | Cryobiology |
The Zeeman energy is the interaction energy between the magnetization and any externally applied field. It's written as:
where H is the applied field and µ is the vacuum permeability.
The Zeeman energy favors alignment of the magnetization parallel to the applied field. | 7 | Magnetic Ordering |
The most famous cold fusion claims were made by Stanley Pons and Martin Fleischmann in 1989. After a brief period of interest by the wider scientific community, their reports were called into question by nuclear physicists. Pons and Fleischmann never retracted their claims, but moved their research program from the US to France after the controversy erupted. | 3 | Nuclear Fusion |
The MIRAGE reporting guidelines provide essential frameworks for subsequent projects related with the development of both software tools for the analysis of experimental glycan data and databases for the deposition of interaction analysis data (e.g. from glycan microarray experiments) and structural analysis data (e.g. from mass spectrometry and liquid chromatography experiments). As the guidelines include the definitions of the minimum information required for reporting glycomics experiments comprehensively, this information is incorporated in database structures, data acquisition forms and data exchange formats.<br>
The following databases comply with the MIRAGE guidelines:
* UniCarb-DB, which stores curated data and information on glycan structures and associated fragment data characterised by LC-Tandem_mass spectrometry strategies.
* [https://glycostore.org/ GlycoStore] a curated Chromatography, Electrophoresis and Mass spectrometry derived composition database of N-, O-, glycosphingolipid (GSL) glycans and free oligosaccharides associated with a range of glycoproteins, glycolipids and biotherapeutics.
* UniCarb-DR a MS data repository for glycan structures
* [https://glycopost.glycosmos.org/ GlycoPOST] a mass spectra repository for glycomics and glycoproteomics
The following projects refer to the MIRAGE standards:
* [https://glytoucan.org/ GlyTouCan] is a glycan structure repository where unique identifiers are assigned to individually reported glycan structures
* [http://www.unicarbkb.org/ UniCarbKB] a database of glycans and glycoproteins
* [http://www.glygen.org/index.html GlyGen], a data integration and dissemination project for carbohydrate and glycoconjugate related data
* [https://glyconnect.expasy.org/ GlyConnect], an integrated platform for glycomics and glycoproteomics | 6 | Carbohydrates |
Genetic disorders are often an issue within captive populations due to the fact that the populations are usually established from a small number of founders. In large, outbreeding populations, the frequencies of most deleterious alleles are relatively low, but when a population undergoes a bottleneck during the founding of a captive population, previously rare alleles may survive and increase in number. Further inbreeding within the captive population may also increase the likelihood that deleterious alleles will be expressed due to increasing homozygosity within the population. The high occurrence of genetic disorders within a captive population can threaten both the survival of the captive population and its eventual reintroduction back into the wild. If the genetic disorder is dominant, it may be possible to eliminate the disease completely in a single generation by avoiding breeding of the affected individuals. However, if the genetic disorder is recessive, it may not be possible to completely eliminate the allele due to its presence in unaffected heterozygotes. In this case, the best option is to attempt to minimize the frequency of the allele by selectively choosing mating pairs. In the process of eliminating genetic disorders, it is important to consider that when certain individuals are prevented from breeding, alleles and therefore genetic diversity are removed from the population; if these alleles are not present in other individuals, they may be lost completely. Preventing certain individuals from the breeding also reduces the effective population size, which is associated with problems such as the loss of genetic diversity and increased inbreeding. | 1 | Cryobiology |
Carbohydrate chemistry is a large and economically important branch of organic chemistry. Some of the main organic reactions that involve carbohydrates are:
* Amadori rearrangement
* Carbohydrate acetalisation
* Carbohydrate digestion
* Cyanohydrin reaction
* Koenigs–Knorr reaction
* Lobry de Bruyn–Van Ekenstein transformation
* Nef reaction
* Wohl degradation | 6 | Carbohydrates |
In 1989, after Fleischmann and Pons had made their claims, many research groups tried to reproduce the Fleischmann-Pons experiment, without success. A few other research groups, however, reported successful reproductions of cold fusion during this time. In July 1989, an Indian group from the Bhabha Atomic Research Centre (P. K. Iyengar and M. Srinivasan) and in October 1989, John Bockris' group from Texas A&M University reported on the creation of tritium. In December 1990, professor Richard Oriani of the University of Minnesota reported excess heat.
Groups that did report successes found that some of their cells were producing the effect, while other cells that were built exactly the same and used the same materials were not producing the effect. Researchers that continued to work on the topic have claimed that over the years many successful replications have been made, but still have problems getting reliable replications. Reproducibility is one of the main principles of the scientific method, and its lack led most physicists to believe that the few positive reports could be attributed to experimental error. The DOE 2004 report said among its conclusions and recommendations: | 3 | Nuclear Fusion |
The exchange energy is a phenomenological continuum description of the quantum-mechanical exchange interaction. It is written as:
where A is the exchange constant; m, m and m are the components of m;
and the integral is performed over the volume of the sample.
The exchange energy tends to favor configurations where the magnetization varies only slowly across the sample. This energy is minimized when the magnetization is perfectly uniform. | 7 | Magnetic Ordering |
When no external field is applied, the antiferromagnetic structure corresponds to a vanishing total magnetization. In an external magnetic field, a kind of ferrimagnetic behavior may be displayed in the antiferromagnetic phase, with the absolute value of one of the sublattice magnetizations differing from that of the other sublattice, resulting in a nonzero net magnetization. Although the net magnetization should be zero at a temperature of absolute zero, the effect of spin canting often causes a small net magnetization to develop, as seen for example in hematite.
The magnetic susceptibility of an antiferromagnetic material typically shows a maximum at the Néel temperature. In contrast, at the transition between the ferromagnetic to the paramagnetic phases the susceptibility will diverge. In the antiferromagnetic case, a divergence is observed in the staggered susceptibility.
Various microscopic (exchange) interactions between the magnetic moments or spins may lead to antiferromagnetic structures. In the simplest case, one may consider an Ising model on a bipartite lattice, e.g. the simple cubic lattice, with couplings between spins at nearest neighbor sites. Depending on the sign of that interaction, ferromagnetic or antiferromagnetic order will result. Geometrical frustration or competing ferro- and antiferromagnetic interactions may lead to different and, perhaps, more complicated magnetic structures.
The relationship between magnetization and the magnetizing field is non-linear like in ferromagnetic materials. This fact is due to the contribution of the hysteresis loop, which for ferromagnetic materials involves a residual magnetization. | 7 | Magnetic Ordering |
The categorization of amylopectin began with the first observation in starch in 1716 by Antonie van Leeuwenhoek, where he differentiated starch into two fundamental structural components.
The terms amylose and amylopectin where not coined until 1906, by French researchers Maquenee and Roux in the course of an examination of starch, where they explained variations in the properties of starches according to the mixture of these related substances and variable saccharification by malt extract. Since then and through the 1940s, research focused on various methods of separation, like fractional precipitation or enzymatically. This gave rise to the Meyer definition of amylose and "reserv[ing] the name amylopectin to carbohydrates that are branched molecule, degraded by b-amylase only to the stage of residual dextrin". Meyer also proposed the tree like structure model for amylopectin.
The currently accepted structural model was proposed in 1972, based on the cluster organization of double helical structures. Other models have been proposed since, such as the Bertoft BB model, or building block and backbone model in 2012. This model claims short chains are the structural building blocks and long chains the backbone to carry the building blocks, and that the different lengths of chain are separated by their position and direction of elongation | 6 | Carbohydrates |
In a horizontal sedimentation tank, some particles may not follow the diagonal line in Fig. 1, while settling faster as they grow. So this says that particles can grow and develop a higher settling velocity if a greater depth with longer retention time. However, the collision chance would be even greater if the same retention time were spread over a longer, shallower tank. In fact, in order to avoid hydraulic short-circuiting, tanks usually are made 3–6 m deep with retention times of a few hours. | 5 | Separation Processes |
Various biomaterials, whether they are biological, synthetic, or a combination of both, can be used to create scaffolds, which when implanted in a human body can promote host tissue regeneration. First, cells from the patient in which the scaffold will be implanted in are harvested. These cells are expanded and seeded into the created scaffold, which is then inserted inside the human body. The human body serves as a bioreactor, which allows the formation of an extracellular matrix (ECM) along with fibrous proteins around the scaffold to provide the necessary environment for the heart and circulatory system. The initial implantation of the foreign scaffold triggers various signaling pathways guided by the foreign body response for cell recruitment from neighboring tissues. The new nanofiber network surrounding the scaffold mimics the native ECM of the host body. Once cells begin to populate the cell, the scaffold is designed to gradually degrade, leaving behind a constructed heart valve made of the host body's own cells that is fully capable of cell repopulation and withstanding environmental changes within the body. The scaffold designed for tissue engineering is one of the most crucial components because it guides tissue construction, viability, and functionality long after implantation and degradation. | 2 | Tissue Engineering |
One of the greatest obstacles in sonoluminescence research has been trying to obtain measurements of the interior of the bubble. Most measurements, like temperature and pressure, are indirectly measured using models and bubble dynamics. | 0 | Luminescence |
Intestinal organoids grown from rectal biopsies using culture protocols established by the Clevers group have been used to model cystic fibrosis, and led to the first application of organoids for personalised treatment. Cystic fibrosis is an inherited disease that is caused by gene mutations of the cystic fibrosis transmembrane conductance regulator gene that encodes an epithelial ion channel necessary for healthy epithelial surface fluids. Studies by the laboratory of Jeffrey Beekman (Wilhelmina Childrens Hospital, University Medical Center Utrecht, The Netherlands) described in 2013 that stimulation of colorectal organoids with cAMP-raising agonists such as forskolin or cholera toxin induced rapid swelling of organoids in a fully CFTR dependent manner. Whereas organoids from non-cystic fibrosis subjects swell in response to forskolin as a consequence of fluid transport into the organoids lumens, this is severely reduced or absent in organoids derived from people with cystic fibrosis. Swelling could be restored by therapeutics that repair the CFTR protein (CFTR modulators), indicating that individual responses to CFTR modulating therapy could be quantitated in a preclinical laboratory setting. Schwank et al. also demonstrated that the intestinal cystic fibrosis organoid phenotype could be repaired by CRISPR-Cas9 gene editing in 2013.
Follow-up studies by Dekkers et al. in 2016 revealed that quantitative differences in forskolin-induced swelling between intestinal organoids derived from people with cystic fibrosis associate with known diagnostic and prognostic markers such as CFTR gene mutations or in vivo biomarkers of CFTR function. In addition, the authors demonstrated that CFTR modulator responses in intestinal organoids with specific CFTR mutations correlated with published clinical trial data of these treatments. This led to preclinical studies where organoids from patients with extremely rare CFTR mutations for who no treatment was registered were found to respond strongly to a clinically available CFTR modulator. The suggested clinical benefit of treatment for these subjects based on the preclinical organoid test was subsequently confirmed upon clinical introduction of treatment by members of the clinical CF center under supervision of Kors van der Ent (Department of Paediatric Pulmonology, Wilhelmina Children's Hospital, University Medical Center Utrecht, The Netherlands). These studies show for the first time that organoids can be used for the individual tailoring of therapy or personalised medicine. | 2 | Tissue Engineering |
The Frozen Ark is a charitable frozen zoo project created jointly by the Zoological Society of London, the Natural History Museum and University of Nottingham. The project aims to preserve the DNA and living cells of endangered species to retain the genetic knowledge for the future. The Frozen Ark collects and stores samples taken from animals in zoos and those threatened with extinction in the wild. Its current director is Michael W. Bruford (Cardiff University). The Frozen Ark was a finalist for the Saatchi & Saatchi Award for World Changing Ideas in 2006.
The project was founded by Ann Clarke, her husband Bryan Clarke and Dame Anne McLaren. Since Bryan Clarkes death in 2014, the Frozen Arks interim director has been Mike Bruford. | 1 | Cryobiology |
Carnobacterium pleistocenium is a recently discovered bacterium from the arctic part of Alaska. It was found in permafrost, seemingly frozen there for 32,000 years. Melting the ice, however, brought these extremophiles back to life. This is the first case of an organism "coming back to life" from ancient ice. These bacterial cells were discovered in a tunnel dug by the Army Corps of Engineers in the 1960s to allow scientists to study the permafrost in preparation for the construction of the Trans-Alaska pipeline system.
The discovery of this bacterium is of particular interest for NASA, for it may be possible for such life to exist in the permafrost of Mars or on the surface of Europa. It is also of interest for scientists investigating the potential for cryogenically freezing life forms to reduce the transportation costs (in terms of life support systems) that would be associated with long-duration space travel. | 1 | Cryobiology |
Methanediol, also known as formaldehyde monohydrate or methylene glycol, is an organic compound with chemical formula . It is the simplest geminal diol. In aqueous solutions it coexists with oligomers (short polymers). The compound is closely related and convertible to the industrially significant derivatives paraformaldehyde (), formaldehyde (), and 1,3,5-trioxane ().
Methanediol is a product of the hydration of formaldehyde. The equilibrium constant for hydration is estimated to be 10, predominates in dilute (<0.1%) solution. In more concentrated solutions, it oligomerizes to . | 6 | Carbohydrates |
Endangered animal species and breeds are preserved using similar techniques. Animal species can be preserved in genebanks, which consist of cryogenic facilities used to store living sperm, eggs, or embryos. For example, the Zoological Society of San Diego has established a "frozen zoo" to store such samples using cryopreservation techniques from more than 355 species, including mammals, reptiles, and birds.
A potential technique for aiding in reproduction of endangered species is interspecific pregnancy, implanting embryos of an endangered species into the womb of a female of a related species, carrying it to term. It has been carried out for the Spanish ibex. | 1 | Cryobiology |
In polymer chemistry photo-oxidation (sometimes: oxidative photodegradation) is the degradation of a polymer surface due to the combined action of light and oxygen. It is the most significant factor in the weathering of plastics. Photo-oxidation causes the polymer chains to break (chain scission), resulting in the material becoming increasingly brittle. This leads to mechanical failure and, at an advanced stage, the formation of microplastics. In textiles the process is called phototendering.
Technologies have been developed to both accelerate and inhibit this process. For example, plastic building components like doors, window frames and gutters are expected to last for decades, requiring the use of advanced UV-polymer stabilizers. Conversely, single-use plastics can be treated with biodegradable additives to accelerate their fragmentation.
Many pigments and dyes can similarly have effects due to their ability to absorb UV-energy. | 8 | Ultraviolet Radiation |
From a study of lithium abundances in 53 T Tauri stars, it has been found that lithium depletion varies strongly with size, suggesting that lithium burning by the P-P chain, during the last highly convective and unstable stages during the pre–main sequence later phase of the Hayashi contraction may be one of the main sources of energy for T Tauri stars. Rapid rotation tends to improve mixing and increase the transport of lithium into deeper layers where it is destroyed. T Tauri stars generally increase their rotation rates as they age, through contraction and spin-up, as they conserve angular momentum. This causes an increased rate of lithium loss with age. Lithium burning will also increase with higher temperatures and mass, and will last for at most a little over 100 million years.
The P-P chain for lithium burning is as follows
It will not occur in stars less than sixty times the mass of Jupiter. In this way, the rate of lithium depletion can be used to calculate the age of the star. | 3 | Nuclear Fusion |
The Pyrenean ibex went extinct in 2000. In 2003 frozen cells from the last one (a female killed by a falling branch) were used to clone 208 embryos, of which 7 successfully implanted in goats, and one made it to term. That one ibex died of respiratory failure just after birth; quite possibly as a result of the cloning process, its lungs had not developed properly. There may not be enough individuals' cells preserved to create a breeding population. Despite the death of the ibex, DNA analysis revealed that the offspring was a legitimate clone from its last living descendent. | 1 | Cryobiology |
Candoluminescence is the light given off by certain materials at elevated temperatures (usually when exposed to a flame) that has an intensity at some wavelengths which can, through chemical action in flames, be higher than the blackbody emission expected from incandescence at the same temperature. The phenomenon is notable in certain transition-metal and rare-earth oxide materials (ceramics) such as zinc oxide, cerium(IV) oxide and thorium dioxide. | 0 | Luminescence |
The process efficiency of sensor-based ore sorting is described in detail by C. Robben in 2014. The total process efficiency is subdivided into the following sub-process efficiencies; Platform efficiency, preparation efficiency, presentation efficiency, detection efficiency and separation efficiency. All the sub-process contribute to the total process efficiency, of course in combination with the liberation characteristics of the bulk material that the technology is applied to. The detailed description of the sib-processes and their contribution to the total process efficiency can be found in the literature. | 5 | Separation Processes |
The development of UVGI traces back to 1878 when Arthur Downes and Thomas Blunt found that sunlight, particularly its shorter wavelengths, hindered microbial growth. Expanding upon this work, Émile Duclaux, in 1885, identified variations in sunlight sensitivity among different bacterial species. A few years later, in 1890, Robert Koch demonstrated the lethal effect of sunlight on Mycobacterium tuberculosis, hinting at UVGI's potential for combating diseases like tuberculosis.
Subsequent studies further defined the wavelengths most efficient for germicidal inactivation. In 1892, it was noted that the UV segment of sunlight had the most potent bactericidal effect. Research conducted in the early 1890s demonstrated the superior germicidal efficacy of UV-C compared to UV-A and UV-B.
The mutagenic effects of UV were first unveiled in a 1914 study that observed metabolic changes in Bacillus anthracis upon exposure to sublethal doses of UV. Frederick Gates, in the late 1920s, offered the first quantitative bactericidal action spectra for Staphylococcus aureus and Bacillus coli, noting peak effectiveness at 265 nm. This matched the absorption spectrum of nucleic acids, hinting at DNA damage as the key factor in bacterial inactivation. This understanding was solidified by the 1960s through research demonstrating the ability of UV-C to form thymine dimers, leading to microbial inactivation. These early findings collectively laid the groundwork for modern UVGI as a disinfection tool. | 8 | Ultraviolet Radiation |
Super-LumiNova is a brand name under which strontium aluminate–based non-radioactive and nontoxic photoluminescent or afterglow pigments for illuminating markings on watch dials, hands and bezels, etc. in the dark are marketed. When activated with a suitable dopant (Europium and Dysprosium), it acts as a photoluminescent phosphor with long persistence of phosphorescence. This technology offers up to ten times higher brightness than previous zinc sulfide–based materials.
These types of phosphorescent pigments, often called lume, operate like a light battery. After sufficient activation by sunlight, fluorescent, LED, UV (backlight), incandescent and other light sources, they glow in the dark for hours. Electrons within the pigment are being "excited" by ultraviolet light exposure – the excitation wavelengths for strontium aluminate range from 200 to 450 nm electromagnetic radiation – to a higher energetic state and after the excitation source is removed, fall back to their normal energetic state by releasing the energy loss as visible light over a period of time. Although fading over time, appropriately thick applicated larger markings remain visible for dark adapted human eyes for the whole night. This Ultraviolet light exposure induced activation and subsequent light emission process can be repeated again and again. | 0 | Luminescence |
It is sometimes stated that "the conjugate of a weak acid is a strong base". Such a statement is incorrect. For example, acetic acid is a weak acid which has a = 1.75 x 10. Its conjugate base is the acetate ion with K = 10/K = 5.7 x 10 (from the relationship K × K = 10), which certainly does not correspond to a strong base. The conjugate of a weak acid is often a weak base and vice versa. | 4 | Acids + Bases |
Unlike ferromagnetism, the magnetization curves of ferrimagnetism can take many different shapes depending on the strength of the interactions and the relative abundance of atoms. The most notable instances of this property are that the direction of magnetization can reverse while heating a ferrimagnetic material from absolute zero to its critical temperature, and that strength of magnetization can increase while heating a ferrimagnetic material to the critical temperature, both of which cannot occur for ferromagnetic materials. These temperature dependencies have also been experimentally observed in NiFeCrO and LiFeCeO.
A temperature lower than the Curie temperature, but at which the opposing magnetic moments are equal (resulting in a net magnetic moment of zero) is called a magnetization compensation point. This compensation point is observed easily in garnets and rare-earth–transition-metal alloys (RE-TM). Furthermore, ferrimagnets may also have an angular momentum compensation point, at which the net angular momentum vanishes. This compensation point is crucial for achieving fast magnetization reversal in magnetic-memory devices. | 7 | Magnetic Ordering |
The liver is a major organ of metabolism, and it is related to glycogen storage, decomposition of red blood cells, certain protein and hormone synthesis, and detoxification. Within these functions, its detoxification response is essential for new drug development and clinical trials. In addition, because of its multi-functions, the liver is prone to many diseases, and liver diseases have become a global challenge.
Liver-on-a-chip devices utilize microfluidic techniques to simulate the hepatic system by imitating complex hepatic lobules that involve liver functions. Liver-on-a-chip devices provide a good model to help researchers work on dysfunction and pathogenesis of the liver with relatively low cost. Researchers use primary rat hepatocytes and other nonparenchymal cells. This coculture method is extensively studied and is proved to be beneficial for extension of hepatocytes survival time and support the performance of liver-specific functions. Many liver-on-a-chip systems are made of poly(dimethylsiloxane) (PDMS) with multiple channels and chambers based on specific design and objective. PDMS is used and has become popular because it has relatively low price for raw materials, and it is also easily molded for microfluidic devices. But PDMS can absorb important signaling molecules including proteins and hormones. Other more inert materials such as polysulfone or polycarbonate are used in liver-chips.
A study by Emulate researchers assessed advantages of using liver-chips predicting drug-induced liver injury which could reduce the high costs and time needed in drug development workflows/pipelines, sometimes described as the pharmaceutical industry's "productivity crisis". Zaher Nahle subsequently outlined 12 "reasons why micro-physiological systems (MPS) like organ-chips are better at modeling human diseases".
One design from Kane et al. cocultures primary rat hepatocytes and 3T3-J2 fibroblasts in an 8*8 element array of microfluidic wells. Each well is separated into two chambers. The primary chamber contains rat hepatocytes and 3T3-J2 fibroblasts and is made of glass for cells adhesion. Each of primary chamber is connected to a microfluidic network that supply metabolic substrate and remove metabolic byproducts. A 100 µm thick membrane of PDMS separates the primary and secondary chamber, allowing the secondary chamber to be connected to another microfluidic network that perfuses 37 °C room air with 10% carbon dioxide, and producing air exchange for rat hepatocytes. The production of urea and steady-state protein proves the viability of this device for use in high-throughput toxicity studies.
Another design from Kang et al. cocultures primary rat hepatocytes and endothelial cells. A single-channel is made first. Hepatocytes and endothelial cells are then planted on the device and are separated by a thin Matrigel layer in between. The metabolic substrate and metabolic byproducts share this channel to be supplied or removed. Later, a dual-channel is made, and endothelial cells and hepatocytes cells have their own channels to supply the substrate or remove the byproduct. The production of urea and positive result on hepatitis B virus (HBV) replication test shows its potential to study hepatotropic viruses.
There are a few other applications on liver-on-a-chip. Lu et al. developed a liver tumor-on-a-chip model. The decellularized liver matrix (DLM)-gelatin methacryloyl (GelMA)-based biomimetic liver tumor-on-a-chip proved to be a suitable design for further anti-tumor studies. Zhou et al. analyzed alcohol injures on the hepatocytes and the signaling and recovery.
The liver-on-a-chip has shown its great potential for liver-related research. Future goals for liver-on-a-chip devices focus on recapitulating a more realistic hepatic environment, including reagents in fluids, cell types, extending survival time, etc. | 2 | Tissue Engineering |
There are a number of non-invasive head cooling caps and helmets designed to target cooling at the brain. A hypothermia cap is typically made of a synthetic material such as neoprene, silicone, or polyurethane and filled with a cooling agent such as ice or gel which is either cooled to a very cold temperature, , before application or continuously cooled by an auxiliary control unit. Their most notable uses are in preventing or reducing alopecia in chemotherapy, and for preventing cerebral palsy in babies born with hypoxic ischemic encephalopathy. In the continuously cooled iteration, coolant is cooled with the aid of a compressor and pumped through the cooling cap. Circulation is regulated by means of valves and temperature sensors in the cap. If the temperature deviates or if other errors are detected, an alarm system is activated. The frozen iteration involves continuous application of caps filled with Crylon gel cooled to to the scalp before, during and after intravenous chemotherapy. As the caps warm on the head, multiple cooled caps must be kept on hand and applied every 20 to 30 minutes. | 1 | Cryobiology |
Thick-film dielectric electroluminescent technology (TDEL) is a phosphor-based flat panel display technology developed by Canadian company iFire Technology Corp. TDEL is based on inorganic electroluminescent (IEL) technology that combines both thick-and thin-film processes. The TDEL structure is made with glass or other substrates, consisting of a thick-film dielectric layer and a thin-film phosphor layer sandwiched between two sets of electrodes to create a matrix of pixels. Inorganic phosphors within this matrix emit light in the presence of an alternating electric field. | 0 | Luminescence |
The K factor or characterization factor is defined from Rankine boiling temperature °R=1.8Tb[k] and relative to water density ρ at 60°F:
K(UOP) =
The K factor is a systematic way of classifying a crude oil according to its paraffinic, naphthenic, intermediate or aromatic nature. 12.5 or higher indicate a crude oil of predominantly paraffinic constituents, while 10 or lower indicate a crude of more aromatic nature. The K(UOP) is also referred to as the UOP K factor or just UOPK. | 5 | Separation Processes |
The earliest barometers were simply glass tubes that were closed at one end and filled with mercury. The tube was then inverted and its open end was submerged in a cup of mercury. The mercury then drained out of the tube until the pressure of the mercury in the tube — as measured at the surface of the mercury in the cup — equaled the atmosphere's pressure on the same surface.
In order to produce barometric light, the glass tube must be very clean and the mercury must be pure. If the barometer is then shaken, a band of light will appear on the glass at the meniscus of the mercury whenever the mercury moves downward.
When mercury contacts glass, the mercury transfers electrons to the glass. Whenever the mercury pulls free of the glass, these electrons are released from the glass into the surroundings, where they collide with gas molecules, causing the gas to glow — just as the collision of electrons and neon atoms causes a neon lamp to glow. | 0 | Luminescence |
To help mitigate inbreeding depression for two endangered species, the Black-footed ferret(Mustela nigripes), Revive & Restore facilitates on-going efforts to clone individuals from historic cell lines stored at the San Diego Zoo Wildlife Alliance Frozen Zoo. The program seeks to restore genetic variation lost from the living gene pool.
On December 10, 2020, the world's first cloned black-footed ferret was born. This ferret, named Elizabeth Ann, marked the first time a U.S. endangered species was successfully cloned.
The cells of two 1980s wild-caught black-footed ferrets that never bred in captivity were preserved in the San Diego Wildlife Alliance Frozen Zoo. One of them was cloned to increase genetic diversity in this species in December 2020. More clones of both are planned. They will initially be bred separately from the non-cloned population. | 1 | Cryobiology |
There is no time-dependence of the magnetization when the nanoparticles are either completely blocked () or completely superparamagnetic (). There is, however, a narrow window around where the measurement time and the relaxation time have comparable magnitude. In this case, a frequency-dependence of the susceptibility can be observed. For a randomly oriented sample, the complex susceptibility is:
where
* is the frequency of the applied field
* is the susceptibility in the superparamagnetic state
* is the susceptibility in the blocked state
* is the relaxation time of the assembly
From this frequency-dependent susceptibility, the time-dependence of the magnetization for low-fields can be derived: | 7 | Magnetic Ordering |
The stream is exposed to ozone and ozone is unstable at atmospheric condition. The ozone (O3) decomposes into oxygen (O2) and more oxygen is dissolved into the stream. The pathogen is oxidised to form carbon dioxide. This process eliminates the odour of the stream but result in slightly acidic product due to the effect of carbon dioxide present. | 5 | Separation Processes |
Colorless fluorescent dyes that emit blue light under UV are added as optical brighteners to paper and fabrics. The blue light emitted by these agents counteracts yellow tints that may be present and causes the colors and whites to appear whiter or more brightly colored.
UV fluorescent dyes that glow in the primary colors are used in paints, papers, and textiles either to enhance color under daylight illumination or to provide special effects when lit with UV lamps. Blacklight paints that contain dyes that glow under UV are used in a number of art and aesthetic applications.
Amusement parks often use UV lighting to fluoresce ride artwork and backdrops. This often has the side effect of causing rider's white clothing to glow light-purple.
To help prevent counterfeiting of currency, or forgery of important documents such as driver's licenses and passports, the paper may include a UV watermark or fluorescent multicolor fibers that are visible under ultraviolet light. Postage stamps are tagged with a phosphor that glows under UV rays to permit automatic detection of the stamp and facing of the letter.
UV fluorescent dyes are used in many applications (for example, biochemistry and forensics). Some brands of pepper spray will leave an invisible chemical (UV dye) that is not easily washed off on a pepper-sprayed attacker, which would help police identify the attacker later.
In some types of nondestructive testing UV stimulates fluorescent dyes to highlight defects in a broad range of materials. These dyes may be carried into surface-breaking defects by capillary action (liquid penetrant inspection) or they may be bound to ferrite particles caught in magnetic leakage fields in ferrous materials (magnetic particle inspection). | 8 | Ultraviolet Radiation |
The role of gastric acid in digestion was established in the 1820s and 1830s by William Beaumont on Alexis St. Martin, who, as a result of an accident, had a fistula (hole) in his stomach, which allowed Beaumont to observe the process of digestion and to extract gastric acid, verifying that acid played a crucial role in digestion. | 4 | Acids + Bases |
The Super-Kamiokande is a 50,000 ton water Cherenkov detector underground. The primary uses for this detector in Japan in addition to neutrino observation is cosmic ray observation as well as searching for proton decay. In 1998, the Super-Kamiokande was the site of the Super-Kamiokande experiment which led to the discovery of neutrino oscillation, the process by neutrinos change their flavor, either to electron, muon or tau.
The Super-Kamiokande experiment began in 1996 and is still active. In the experiment, the detector works by being able to spot neutrinos by analyzing water molecules and detecting electrons being removed from them which then produces a blue Cherenkov light, which is produced by neutrinos. Therefore, when this detection of blue light happens it can be inferred that a neutrino is present and counted. | 3 | Nuclear Fusion |
Directed differentiation is primarily applied to pluripotent stem cells (PSCs) of mammalian origin, in particular mouse and human cells for biomedical research applications. Since the discovery of embryonic stem (ES) cells (1981) and induced pluripotent stem (iPS) cells (2006), source material is potentially unlimited.
Historically, embryonic carcinoma (EC) cells have also been used. Fibroblasts or other differentiated cell types have been used for direct reprogramming strategies. | 2 | Tissue Engineering |
Regenerative medicine involves processes of replacing, engineering or regenerating human cells, tissues or organs to restore or establish normal function. A major technology of regenerative medicine is tissue engineering, which has variously been defined as "an interdisciplinary field that applies the principles of engineering and the life sciences toward the development of biological substitutes that restore, maintain, or improve tissue function", or "the creation of new tissue by the deliberate and controlled stimulation of selected target cells through a systematic combination of molecular and mechanical signals". | 2 | Tissue Engineering |
Fused deposition modeling (FDM) is more common and inexpensive compared to selective laser sintering. This printer uses a printhead that is similar in structure to an inkjet printer; however, ink is not used. Plastic beads are heated at high temperature and released from the printhead as it moves, building the object in thin layers. A variety of plastics can be used with FDM printers. Additionally, most of the parts printed by FDM are typically composed from the same thermoplastics that are utilized in tradition injection molding or machining techniques. Due to this, these parts have analogous durability, mechanical properties, and stability characteristics. Precision control allows for a consistent release amount and specific location deposition for each layer contributing to the shape. As the heated plastic is deposited from the printhead, it fuses or bonds to the layers below. As each layer cools, they harden and gradually take hold of the solid shape intended to be created as more layers are contributed to the structure. | 2 | Tissue Engineering |
3D-printing techniques have been used in a variety of industries for the overall goal of fabricating a product. Organ printing, on the other hand, is a novel industry that utilizes biological components to develop therapeutic applications for organ transplants. Due to the increased interest in this field, regulation and ethical considerations desperately need to be established. Specifically, there can be legal complications from pre-clinical to clinical translation for this treatment method. | 2 | Tissue Engineering |
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. | 6 | Carbohydrates |
Low-carbohydrate diets may miss the health advantages – such as increased intake of dietary fiber – afforded by high-quality carbohydrates found in legumes and pulses, whole grains, fruits, and vegetables. A "meta-analysis, of moderate quality," included as adverse effects of the diet halitosis, headache and constipation.
Carbohydrate-restricted diets can be as effective as low-fat diets in helping achieve weight loss over the short term when overall calorie intake is reduced. An Endocrine Society scientific statement said that "when calorie intake is held constant [...] body-fat accumulation does not appear to be affected by even very pronounced changes in the amount of fat vs carbohydrate in the diet." In the long term, effective weight loss or maintenance depends on calorie restriction, not the ratio of macronutrients in a diet. The reasoning of diet advocates that carbohydrates cause undue fat accumulation by increasing blood insulin levels, and that low-carbohydrate diets have a "metabolic advantage", is not supported by clinical evidence. Further, it is not clear how low-carbohydrate dieting affects cardiovascular health, although two reviews showed that carbohydrate restriction may improve lipid markers of cardiovascular disease risk.
Carbohydrate-restricted diets are no more effective than a conventional healthy diet in preventing the onset of type 2 diabetes, but for people with type 2 diabetes, they are a viable option for losing weight or helping with glycemic control. There is limited evidence to support routine use of low-carbohydrate dieting in managing type 1 diabetes. The American Diabetes Association recommends that people with diabetes should adopt a generally healthy diet, rather than a diet focused on carbohydrate or other macronutrients.
An extreme form of low-carbohydrate diet – the ketogenic diet – is established as a medical diet for treating epilepsy. Through celebrity endorsement during the early 21st century, it became a fad diet as a means of weight loss, but with risks of undesirable side effects, such as low energy levels and increased hunger, insomnia, nausea, and gastrointestinal discomfort. The British Dietetic Association named it one of the "top 5 worst celeb diets to avoid in 2018". | 6 | Carbohydrates |
Ion separation is another application of magnetic separation. The separation is driven by the magnetic field that induces a separating force. The force differentiate then between heavy and lighter ions causing the separation. This phenomenon has been demonstrated on test bench and pilot scale. | 5 | Separation Processes |
OFM can be fabricated into a range of different product presentations for tissue engineering applications, and can be functionalized with therapeutic agents including silver, doxycycline and hyaluronic acid. OFM has been commercialized as single and multi-layered sheets, reinforced biologics and powders.
When placed in the body OFM does not elicit a negative inflammatory response and is absorbed into the regenerating tissues via a process called tissue remodeling. | 2 | Tissue Engineering |
Common methods include those of the DISCO family, including 3DISCO, and CLARITY and related protocols. Others include BABB, PEGASOS, SHANEL, SeeDB, CUBIC, ExM, and SHIELD. | 2 | Tissue Engineering |
Although most previous and current research on frustration focuses on spin systems, the phenomenon was first studied in ordinary ice. In 1936 Giauque and Stout published The Entropy of Water and the Third Law of Thermodynamics. Heat Capacity of Ice from 15 K to 273 K, reporting calorimeter measurements on water through the freezing and vaporization transitions up to the high temperature gas phase. The entropy was calculated by integrating the heat capacity and adding the latent heat contributions; the low temperature measurements were extrapolated to zero, using Debyes then recently derived formula. The resulting entropy, S = 44.28 cal/(K·mol) = 185.3 J/(mol·K) was compared to the theoretical result from statistical mechanics of an ideal gas, S = 45.10 cal/(K·mol) = 188.7 J/(mol·K). The two values differ by S' = 0.82 ± 0.05 cal/(K·mol) = 3.4 J/(mol·K). This result was then explained by Linus Pauling to an excellent approximation, who showed that ice possesses a finite entropy (estimated as 0.81 cal/(K·mol) or 3.4 J/(mol·K)) at zero temperature due to the configurational disorder intrinsic to the protons in ice.
In the hexagonal or cubic ice phase the oxygen ions form a tetrahedral structure with an O–O bond length 2.76 Å (276 pm), while the O–H bond length measures only 0.96 Å (96 pm). Every oxygen (white) ion is surrounded by four hydrogen ions (black) and each hydrogen ion is surrounded by 2 oxygen ions, as shown in Figure 5. Maintaining the internal HO molecule structure, the minimum energy position of a proton is not half-way between two adjacent oxygen ions. There are two equivalent positions a hydrogen may occupy on the line of the O–O bond, a far and a near position. Thus a rule leads to the frustration of positions of the proton for a ground state configuration: for each oxygen two of the neighboring protons must reside in the far position and two of them in the near position, so-called ‘ice rules’. Pauling proposed that the open tetrahedral structure of ice affords many equivalent states satisfying the ice rules.
Pauling went on to compute the configurational entropy in the following way: consider one mole of ice, consisting of N O and 2N protons. Each O–O bond has two positions for a proton, leading to 2 possible configurations. However, among the 16 possible configurations associated with each oxygen, only 6 are energetically favorable, maintaining the HO molecule constraint. Then an upper bound of the numbers that the ground state can take is estimated as Ω (). Correspondingly the configurational entropy S = kln(Ω) = Nkln() = 0.81 cal/(K·mol) = 3.4 J/(mol·K) is in amazing agreement with the missing entropy measured by Giauque and Stout.
Although Pauling's calculation neglected both the global constraint on the number of protons and the local constraint arising from closed loops on the Wurtzite lattice, the estimate was subsequently shown to be of excellent accuracy. | 7 | Magnetic Ordering |
Normally, ice crystals grown in solution only exhibit the basal (0001) and prism faces (1010), and appear as round and flat discs. However, it appears the presence of AFPs exposes other faces. It now appears the ice surface 2021 is the preferred binding surface, at least for AFP type I. Through studies on type I AFP, ice and AFP were initially thought to interact through hydrogen bonding (Raymond and DeVries, 1977). However, when parts of the protein thought to facilitate this hydrogen bonding were mutated, the hypothesized decrease in antifreeze activity was not observed. Recent data suggest hydrophobic interactions could be the main contributor. It is difficult to discern the exact mechanism of binding because of the complex water-ice interface. Currently, attempts to uncover the precise mechanism are being made through use of molecular modelling programs (molecular dynamics or the Monte Carlo method). | 1 | Cryobiology |
Many inorganic oxyacids are traditionally called with names ending with the word acid and which also contain, in a somewhat modified form, the name of the element they contain in addition to hydrogen and oxygen. Well-known examples of such acids are sulfuric acid, nitric acid and phosphoric acid.
This practice is fully well-established, and IUPAC has accepted such names. In light of the current chemical nomenclature, this practice is an exception, because systematic names of compounds are formed according to the elements they contain and their molecular structure, not according to other properties (for example, acidity) they have.
IUPAC, however, recommends against calling future compounds not yet discovered with a name ending with the word acid. Indeed, acids can be called with names formed by adding the word hydrogen in front of the corresponding anion; for example, sulfuric acid could just as well be called hydrogen sulfate (or dihydrogen sulfate). In fact, the fully systematic name of sulfuric acid, according to IUPACs rules, would be dihydroxidodioxidosulfur and that of the sulfate ion, tetraoxidosulfate(2−)', Such names, however, are almost never used.
However, the same element can form more than one acid when compounded with hydrogen and oxygen. In such cases, the English practice to distinguish such acids is to use the suffix -ic in the name of the element in the name of the acid containing more oxygen atoms, and the suffix -ous in the name of the element in the name of the acid containing fewer oxygen atoms. Thus, for example, sulfuric acid is HSO, and sulfurous acid, HSO. Analogously, nitric acid is HNO, and nitrous acid, HNO. If there are more than two oxyacids having the same element as the central atom, then, in some cases, acids are distinguished by adding the prefix per- or hypo- to their names. The prefix per-, however, is used only when the central atom is a halogen or a group 7 element. For example, chlorine has the four following oxyacids:
* hypochlorous acid HClO
* chlorous acid HClO
* chloric acid HClO
* perchloric acid HClO
Some elemental atoms can exist in a high enough oxidation state that they can hold one more double-bonded oxygen atom than the perhalic acids do. In that case, any acids regarding such element are given the prefix hyper-. Currently, the only known acid with this prefix is hyperruthenic acid, HRuO.
The suffix -ite occurs in names of anions and salts derived from acids whose names end to the suffix -ous. On the other hand, the suffix -ate occurs in names of anions and salts derived from acids whose names end to the suffix -ic. Prefixes hypo- and per- occur in the name of anions and salts; for example the ion is called perchlorate.
In a few cases, the prefixes ortho- and para- occur in names of some oxyacids and their derivative anions. In such cases, the para- acid is what can be thought as remaining of the ortho- acid if a water molecule is separated from the ortho- acid molecule. For example, phosphoric acid, HPO, has sometimes been called orthophosphoric acid, in order to distinguish it from metaphosphoric acid, HPO. However, according to IUPACs current rules, the prefix ortho-' should only be used in names of orthotelluric acid and orthoperiodic acid, and their corresponding anions and salts. | 4 | Acids + Bases |
Before delving into the mathematical model, it is important to understand that pycnonuclear fusion, in its essence, occurs due to two main events:
* A phenomenon of quantum nature called quantum diffusion.
* Overlap of the wave functions of zero-point oscillations of the nuclei.
Both of these effects are heavily affected by screening. The term screening is generally used by nuclear physicists when referring to plasmas of particularly high density. In order for the pycnonuclear fusion to occur, the two particles must overcome the electrostatic repulsion between them - the energy required for this is called the Coulomb barrier. Due to the presence of other charged particles (mainly electrons) next to the reacting pair, they exert the effect of shielding - as the electrons create an electron cloud around the positively charged ions - effectively reducing the electrostatic repulsion between them, lowering the Coulomb barrier. This phenomenon of shielding is referred to as "screening", and in cases where it is particularly strong, it is called "strong screening". Consequently, in cases where the plasma has a strong screening effect, the rate of pycnonuclear fusion is substantially enhanced.
Quantum tunnelling is the foundation of the quantum physical approach to pycnonuclear fusion. It is closely intertwined with the screening effect, as the transmission coefficient depends on the height of the potential barrier, the mass of the particles, and their relative velocity (since the total energy of the system depends on the kinetic energy). From this follows that the transmission coefficient is very sensitive to the effects of screening. Thus, the effect of screening not only contributes to the reduction of the potential barrier that allows for "classical" fusion to occur via the overlap of the wave functions of the zero-point oscillations of the particles, but also to the increase of the transmission coefficient, both of which increase the rate of pycnonuclear fusion.
On top of the other various jargon related to pycnonuclear fusion, the papers also introduce various regimes, that define the rate of pycnonuclear fusion. Specifically, they identify the zero-temperature, intermediate, and thermally-enhanced regimes as their main ones. | 3 | Nuclear Fusion |