The short version of BDNF fits in a sentence. The long version — which is the one that helps — is below.
This page was last updated on 2025-12-31 and is reviewed periodically as new material appears.
Measuring peptide exposure inside the brain is technically difficult. Selank is degraded rapidly in plasma, and assays must separate intact peptide from fragments, which favors targeted mass spectrometry over immunoassays alone. Reported half-lives are short, on the order of minutes, so effects observed hours later are attributed to downstream signaling rather than to the parent compound. Blood-brain barrier permeability is debated and rarely quantified directly. Gaps include absent dose-response characterization, inconsistent reporting of purity, and almost no pharmacokinetic data from human participants.
Selank is studied chiefly as an animal-model anxiolytic with proposed secondary effects on memory and immune signaling. Reported mechanisms include modulation of the GABA-A receptor complex, inhibition of enkephalin-degrading enzymes, and shifts in monoamine turnover within limbic structures. Some experiments describe increased expression of brain-derived neurotrophic factor in the hippocampus after repeated dosing. No single molecular target has been confirmed, and the peptide does not bind any receptor with the selectivity typical of a conventional small-molecule drug. Mechanism therefore remains a set of hypotheses rather than an established pathway.
Laboratory work relies on standard behavioral paradigms. Rodents are tested in the elevated plus maze, open field, and passive avoidance tasks, with outcomes compared against diazepam or vehicle controls. Intranasal dosing is used most often because it bypasses first-pass metabolism, though intraperitoneal and intravenous routes also appear in published protocols. Biochemical endpoints include tissue BDNF concentrations, cytokine levels, and monoamine metabolites. Human data are limited to small Russian trials reporting reduced anxiety scores; most were not prospectively registered, and few employed independent outcome assessment.
Peptide bonds are vulnerable to protease attack, and Selank is no exception. Measured half-life in serum is short, on the order of minutes in several reports, which explains why intranasal administration is the common route described in the literature. Absorption across the nasal mucosa partially bypasses first-pass hepatic metabolism. Quantitative data on human bioavailability remain limited and are difficult to compare across studies.
Lyophilised material kept dry at minus 20 degrees Celsius or colder is the most stable form, and suppliers commonly state a shelf life of two years or more under those conditions. Once dissolved, degradation accelerates through hydrolysis and deamidation, particularly at alkaline pH or elevated temperature. Working solutions are usually divided into single-use aliquots to avoid repeated freeze-thaw cycles. The choice of reconstitution solvent affects both stability and the ionic strength of the final preparation.
| Property | Value | Notes |
|---|---|---|
| Principal proposed target | GABA-A receptor complex | Hypothesis derived mainly from animal pharmacology |
| Common behavioral assay | Elevated plus maze | Rodent test for anxiety-like behavior |
| Reported molecular marker | Hippocampal BDNF expression | Measured by immunoassay or mRNA quantification |
| Typical dosing route | Intranasal | Chosen to reduce first-pass metabolism |
| Reported plasma half-life | Minutes | Based on limited peptide stability data |
Regulatory status differs sharply by region. Selank holds a Russian marketing authorization, where it is supplied mainly as nasal drops, while authorities elsewhere have not approved it for medical use. Material sold internationally is therefore usually labeled as a research chemical rather than a medicine. Peer-reviewed publications come predominantly from Russian laboratories, and sample sizes are generally small. Whether the compound produces comparable effects under independent, well-controlled replication remains an open question that the broader literature has not settled.
Selank is a synthetic heptapeptide developed in Russia as a structural analogue of tuftsin, a naturally occurring immunomodulatory tetrapeptide. Its sequence, Thr-Lys-Pro-Arg-Pro-Gly-Pro, keeps the tuftsin core at the N-terminus and appends a Pro-Gly-Pro tail. Researchers at the Institute of Molecular Genetics in Moscow synthesized the compound during the 1990s while searching for peptides with combined anxiolytic and immunomodulatory activity. The added tail was intended to resist enzymatic cleavage and prolong the molecule's presence in circulation.
Lyophilized Selank, the dry powder form, is generally stored frozen at minus 20 degrees Celsius or colder for long-term keeping. The solid is hygroscopic and should stay sealed, dry, and protected from light. Once dissolved, the peptide is less stable and is usually held refrigerated at 2 to 8 degrees Celsius for short periods. Repeated freezing and thawing is avoided because it can promote aggregation and loss of activity. Buffers and pH choice also affect how long a solution remains usable.
Solubility behavior is a practical concern for handling. Selank dissolves readily in water and in common aqueous buffers, which simplifies preparation of working solutions. The choice of solvent, ionic strength, and pH can influence aggregation over time, particularly at higher concentrations. Aqueous solutions are typically sterile-filtered before use. Because stability depends on several variables, storage and handling notes should be treated as general guidance rather than fixed rules, and specific values are best confirmed against a certificate of analysis for each batch.
Baikiain is an organic compound with the molecular formula C6H9NO2. Chemically, it is classified as a tetrahydropyridine substituted with a carboxylic acid. Because it contains both this carboxylic acid and an adjacent amine group, it is also an alpha-amino acid. Baikiain is one of the two enantiomers of the chiral compound 4,5-didehydropipecolic acid.
== Economic effects == Scotland's identity and heritage are deeply intertwined with Scotch whisky, a cornerstone of the country's economy exported to nearly 180 markets. The Scotch Whisky Association estimated that Scotland's whisky industry supported 40,000 jobs and accounted for £4.37 billion in exports in 2017. Of that total, single malt Scotch accounted for £1.17 billion in exports, a 14% increase over 2016. In 2022, its exports were valued at over £6 billion for the first time. The industry's contribution to the economy of the UK was estimated as £5.5 billion in 2018; the industry provided £3.8 billion in direct GVA (gross value added) to Scotland. Whisky tourism has also become significant and accounts for £68.3 million per year. One factor negatively affected sales, an extra 3.9% duty on spirits imposed by the UK in 2017. (The effect of the 25% increase in tariffs imposed by the U.S. in October 2019 would not be apparent until 2020.) Nonetheless, by year-end 2017, exports had reached a record-breaking amount. In November 2019, the Association announced that the government of the UK had agreed to consider revising the alcohol taxation system, hopefully producing a new plan that was simplified and "fairer". Exports in 2018 again increased 7.8% by value, and 3.6% in the number of bottles, in spite of the duty imposed in 2017; exports grew to a record level, £4.7 billion. The US imported Scotch whisky with a value of just over £1 billion while the European Union was the second-largest importer, taking 30% of global value.
=== Source Dedicated Server === The Source Dedicated Server (SRCDS) is a standalone launcher for the Source engine that runs multiplayer game sessions without requiring a client. It can be launched through Windows or Linux and can allow for custom levels and assets. Most third-party servers additionally run Metamod:Source and SourceMod, which together provide a framework on top of SRCDS for custom modification of gameplay on existing titles.
==== Food and flavor authentication ==== Foods, flavorings and scents are often sold with the guarantee that chemical additives come from natural sources. This claim becomes hard to test when the chemical compound has a known structure and is readily synthesized in a lab. Authentication of claims about the origins of these chemicals has made good use of various stable isotopes, including those of hydrogen. Combined carbon and hydrogen isotope analysis has been used to test the authenticity of (E)-methyl cinnamate, γ-decalactone and δ-decalactone. Hydrogen and nitrogen isotope ratios have been used for the authentication of alkylpyrazines used as "natural" coffee flavorings.
Sources: en.wikipedia.org
In the back of the chamber, there is packing around the piston or a doughnut-shaped seal with a toroid-shaped sphincter-like spring inside compressing the seal around the piston. This holds the fluid pressure when the piston slides in and out and makes the pump leak-tight. The packing or seals can wear out after prolonged use and can be replaced. The metering rate can be adjusted by varying the strokelength by which the piston moves back and forth or varying the speed of the piston motion. A single-piston pump delivers liquid to the outlet only during the discharge stroke. If the piston's suction and discharge strokes occur at the same speed and liquid is metered out half the time the pump is working, then the overall metering rate averaged over time equals half the average flow rate during the discharge stroke. Some single-piston pumps may have a constant slow piston motion for discharge and a quick retract motion for refilling the pump head. In such cases, the overall metering rate is practically equal to the pumping rate during the discharge stroke.
As a linear triatomic molecule, CO2 has four vibrational modes as shown in the diagram. In the symmetric and the antisymmetric stretching modes, the atoms move along the axis of the molecule. There are two bending modes, which are degenerate, meaning that they have the same frequency and same energy, because of the symmetry of the molecule. When a molecule touches a surface or touches another molecule, the two bending modes can differ in frequency because the interaction is different for the two modes. Some of the vibrational modes are observed in the infrared (IR) spectrum: the antisymmetric stretching mode at wavenumber 2349 cm−1 (wavelength 4.25 μm) and the degenerate pair of bending modes at 667 cm−1 (wavelength 15.0 μm). The symmetric stretching mode does not create an electric dipole so is not observed in IR spectroscopy, but it is detected in Raman spectroscopy at 1388 cm−1 (wavelength 7.20 μm), with a Fermi resonance doublet at 1285 cm−1. In the gas phase, carbon dioxide molecules undergo significant vibrational motions and do not keep a fixed structure. However, in a Coulomb explosion imaging experiment, an instantaneous image of the molecular structure can be deduced. Such an experiment has been performed for carbon dioxide. The result of this experiment, and the conclusion of theoretical calculations based on an ab initio potential energy surface of the molecule, is that none of the molecules in the gas phase are ever exactly linear. This counter-intuitive result is trivially due to the fact that the nuclear motion volume element vanishes for linear geometries.
A clinical study that includes all eligible patients identified by the researchers during the study registration period. The patients are treated in the order in which they are identified. This type of study usually does not have a control group. (NCI) Content validity
Found under the patio at Cromwell Street was the body of the Wests' daughter, Heather, who had been murdered in June 1987 after being abused by her parents all her life. It is said that Heather had begun to tell her friends about her abuse. Barry, her younger brother, would later describe watching, as a seven-year-old, his mother kick Heather repeatedly about the head until she was no longer moving. The Wests had told friends and concerned parties that Heather left home to work at a Devonshire holiday village and on one occasion fabricated a phone call, supposedly from Heather, to allay her siblings' suspicions about her disappearance. Fred would even taunt his children when they misbehaved by jokingly stating, "If you don't behave, you'll end up under the patio like Heather." This was the last known murder that the pair committed. While on remand at HM Prison Birmingham, Fred died by suicide by hanging on 1 January 1995.
== Leadership == On 2 April 2025, President Bola Ahmed Tinubu dissolved the board of NNPC Limited and appointed Bayo Ojulari as the new group chief executive officer(GCEO). Ahmadu Musa Kida was appointed the new non-executive chairman, replacing Chief Pius Akinyelure. Subsequently, on 22 May 2025, President Bola Ahmed Tinubu officially inaugurated the new board and executive leadership at a ceremony held at Aso Rock Villa, Abuja. The 11-member board comprises representatives from Nigeria’s six geopolitical zones, including:
Sources: en.wikipedia.org
=== Financial markets === Thai equities rallied when trading resumed on 9 February. The SET Index closed at 1,400.89, up 46.88 points or 3.46 per cent, having reacted at the open to unofficial results that pointed to Bhumjaithai leading the next government and easing fears of a political vacuum. Turnover reached 102.1 billion baht, the first hundred-billion-baht session in a year and five months. Foreign investors bought a net 16.5 billion baht and institutions a net 6.2 billion, while domestic retail investors sold a net 24.3 billion. Therdsak Thaveeteeratham of Asia Plus Securities called the rally a surprise, saying the market read the result as improving the odds of a stable government formation and of sustained fund flows back into Thai stocks. Asadej Kongsiri, president of the Stock Exchange of Thailand, said investors expected continuity from the outgoing administration and welcomed policies aimed at domestic demand and living costs. Several analysts warned that profit-taking was likely after so sharp a jump.
High-level waste (HLW) is produced by nuclear reactors and the reprocessing of nuclear fuel. The exact definition of HLW differs internationally. After a nuclear fuel rod serves one fuel cycle and is removed from the core, it is considered HLW. Spent fuel rods contain mostly uranium with fission products and transuranic elements generated in the reactor core. Spent fuel is highly radioactive and often hot. HLW accounts for over 95% of the total radioactivity produced in the process of nuclear electricity generation but it contributes to less than 1% of volume of all radioactive waste produced in the UK. Overall, the 60-year-long nuclear program in the UK up until 2019 produced 2150 m3 of HLW. The radioactive waste from spent fuel rods consists primarily of cesium-137 and strontium-90, but it may also include plutonium, which can be considered transuranic waste. The half-lives of these radioactive elements can differ quite extremely. Some elements, such as cesium-137 and strontium-90 have half-lives of approximately 30 years. Meanwhile, plutonium has a half-life that can stretch to as long as 24,000 years. The amount of HLW worldwide is increasing by about 12,000 tonnes per year. A 1000-megawatt nuclear power plant produces about 27 tonnes of spent nuclear fuel (unreprocessed) every year. For comparison, the amount of ash produced by coal power plants in the United States is estimated at 130,000,000 t per year and fly ash is estimated to release 100 times more radiation than an equivalent nuclear power plant.
Albumin I (PA1b) is a hormone-like peptide found in the seeds of legumes such as the pea plant (Pisum sativum) or soya bean (Glycine max) which have been shown to have insecticidal properties. It stimulates kinase activity upon binding a membrane bound 43 kDa receptor within the plant which affects cell proliferation. The structure reveals an inhibitor cystine knot (knottin)-like fold, comprising three beta strands.
The revived Mannerist sphinx of the late 15th century is sometimes thought of as the "French sphinx". Her coiffed head is erect and she has the breasts of a young woman. Often she wears ear drops and pearls as ornaments. Her body is naturalistically rendered as a recumbent lioness. Such sphinxes were revived when the grottesche or "grotesque" decorations of the unearthed Domus Aurea of Nero were brought to light in late 15th-century Rome, and she was incorporated into the classical vocabulary of arabesque designs that spread throughout Europe in engravings during the 16th and 17th centuries. Sphinxes were included in the decoration of the loggia of the Vatican Palace by the workshop of Raphael (1515–20), which updated the vocabulary of the Roman grottesche. The first appearances of sphinxes in French art are in the School of Fontainebleau in the 1520s and 1530s and she continues into the Late Baroque style of the French Régence (1715–1723). From France, she spread throughout Europe, becoming a regular feature of the outdoors decorative sculpture of 18th-century palace gardens, as in the Upper Belvedere Palace in Vienna, Sanssouci Park in Potsdam, La Granja in Spain, Branicki Palace in Białystok, or the late Rococo examples in the grounds of the Portuguese Queluz National Palace (of perhaps the 1760s), with ruffs and clothed chests ending with a little cape.
Sources: en.wikipedia.org
Intranasal administration predominates in both animal and human research because it avoids hepatic first-pass metabolism. Injectable and intraperitoneal routes appear in animal work mainly for comparison.
Behavioral endpoints include time spent in open arms of the elevated plus maze and avoidance latencies. Biochemical endpoints include BDNF concentration, cytokine levels, and monoamine metabolite ratios in brain tissue.
Most published studies are small, originate from a limited number of laboratories, and lack independent replication. Dose-response relationships, measured brain exposure, and long-term outcomes are not well characterized.
Dry powder is best kept sealed, protected from light, and held at minus 20 degrees Celsius or below. Desiccant packaging helps limit moisture uptake because the material is hygroscopic. A sealed vial should be allowed to equilibrate to room temperature before opening to reduce condensation.