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 2026-01-20 and is reviewed periodically as new material appears.
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.
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.
The compound has a calculated molecular weight near 751.9 daltons and carries a net positive charge at physiological pH because of its arginine residue. It dissolves freely in water and in common aqueous buffers, and typically appears as a white or off-white lyophilized powder. The amide backbone makes the molecule susceptible to peptidases, which limits oral use and favors intranasal or parenteral routes. Nomenclature in the literature varies: the substance is also described by the sequence abbreviation TP-7 and by a Russian trade designation.
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.
| 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 |
Quality assessment of Selank samples typically combines purity determination with identity confirmation and counter-ion analysis. Purity is usually reported as a percentage by chromatographic area, with values above 95 percent often quoted for research-grade material. Water content and residual solvents are checked in lyophilized batches because they affect both stability and accurate mass determination. A reported purity figure does not by itself establish that a sample is the intended sequence, so orthogonal methods are needed to rule out sequence isomers or truncation products.
Characterization of Selank in laboratory settings relies on standard peptide analytical techniques. Reverse-phase high-performance liquid chromatography separates the peptide from related impurities and degradation products, while mass spectrometry confirms molecular identity through accurate mass measurement. Amino acid analysis and peptide sequencing verify the primary structure when reference material is unavailable. Because Selank is a short chain, fragmentation-based analysis produces a diagnostic ion pattern that supports confident identification.
Peptide stability depends strongly on temperature, moisture, and pH. Lyophilized Selank is generally most stable when stored cold and dry, with freezer temperatures commonly used for long-term storage. In solution, the compound is susceptible to hydrolysis and to microbial growth if it is not handled aseptically. The C-terminal proline-rich extension appears to slow enzymatic cleavage relative to tuftsin, though quantitative degradation rates vary with the matrix and the conditions tested. Published stability data specific to Selank remain sparse.
The primary structure of Selank is Thr-Lys-Pro-Arg-Pro-Gly-Pro, corresponding to the molecular formula C33H57N11O9 and a monoisotopic mass of roughly 751.9 daltons. The N-terminal threonine and the arginine residue in the fourth position are shared with tuftsin, which carries the sequence Thr-Lys-Pro-Arg. The three additional residues at the C-terminus, Pro-Gly-Pro, extend the chain and are associated with greater resistance to enzymatic degradation. This extension also separates Selank from the shorter parent peptide.
Naming conventions place Selank in the same research family as Semax, another Russian-developed peptide investigated for cognitive effects. The two compounds share a lineage but differ in sequence and in the biological systems proposed as their targets. Semax descends from ACTH fragments, whereas Selank descends from tuftsin. Publications sometimes identify Selank by its full peptide sequence or by laboratory codes rather than one uniform trade name. Because replication outside Russia is limited, reports on its properties are best read alongside the study design and the purity of the material tested.
Reversed-phase high-performance liquid chromatography is the standard technique for estimating peptide purity. The result is a peak-area percentage, which describes how much of the detected material elutes as the main peak in one run. Mass spectrometry confirms the molecular mass and can reveal truncated, adducted, or otherwise modified species. Amino acid analysis or tandem mass spectrometry can address sequence fidelity when identity is in doubt. None of these measurements, taken alone, establishes that a sample is fit for any specific purpose.
Lyophilized selank is normally supplied as a dry powder and is considered stable for extended periods when kept cold and dry. Moisture uptake is the main practical threat, because absorbed water promotes both hydrolysis and aggregation in the solid state. Vials are usually warmed to room temperature before opening so that condensation does not form on the powder. Supplier documentation commonly specifies -20 °C for routine storage, with -80 °C used for material intended to be archived for years.
=== Carbon fixation === C4 photosynthesis, one of the three major carbon-fixing biochemical processes, has arisen independently up to 40 times. About 7,600 plant species of angiosperms use C4 carbon fixation, with many monocots including 46% of grasses such as maize and sugar cane, and dicots including several species in the Chenopodiaceae and the Amaranthaceae.
Guns: 6 × .50 caliber (12.7mm) AN/M2 Browning machine guns with 1,840 total rounds (380 rounds for each on the inboard pair and 270 rounds for each of the outer two pair) Rockets: 6 or 10 × 5.0 in (127 mm) T64 HVAR rockets (P-51D-25, P-51K-10 on) Bombs: 1 × 100 lb (45 kg) or 250 lb (110 kg) bomb or 500 lb (230 kg) bomb on hardpoint under each wing
Downstream processing refers to purification of chemicals, pharmaceuticals and food ingredients produced by fermentation or synthesized by plant and animal tissues, for example antibiotics, citric acid, vitamin E, and insulin. Fractionation refers to a purification strategy in which some relatively inefficient purification method is repeatedly applied to isolate the desired substance in progressively greater purity. Electrolysis refers to the breakdown of substances using an electric current. This removes impurities in a substance that an electric current is run through Sublimation is the process of changing of any substance (usually on heating) from a solid to a gas (or from gas to a solid) without passing through liquid phase. In terms of purification - material is heated, often under vacuum, and the vapors of the material are then condensed back to a solid on a cooler surface. The process thus in its essence is similar to distillation, however the material which is condensed on the cooler surface then has to be removed mechanically, thus requiring different laboratory equipment. Bioleaching is the extraction of metals from their ores through the use of living organisms. Separation process From Crystallization
The 1980s MGN W12 F1 engine used rotary valves but never raced. Between 2002 and 2004 the Australian developer Bishop Innovation and Mercedes-Ilmor tested rotary valves for a F1 V10 engine. Bishop Innovations' patent for the rotary valve engine was bought out by BRV Pty Ltd, owned by Tony Wallis, one of the valves original designers. BRV has constructed several functional motors using the rotary valve technology, such as a Honda CRF 450, which had greater torque at both low (17% increase) and high (9% increase) engine speeds, and also produced more brake horsepower up to around 30% more at functional engine speeds. The engine was also considerably smaller and lighter, as the cylinder head assembly was not as large. A company in the UK called Roton Engine Developments made some progress in 2005 with a two-rotor (one for inlet and one for exhaust) single-cylinder Husaberg motorcycle engine. They filed patents and got an example running in 2006, but were backed by MG Rover which subsequently went bust, leaving Roton without enough funds to continue. The designs surfaced some years later in Australia with Engine Developments Australia Pty Ltd. A prototype casting was produced in 2013 on a Kawasaki Ninja 300 parallel twin unit.
Sources: en.wikipedia.org
== Organic heterocycles and polymers == Radical cations figure prominently in the chemistry and properties of conducting polymers. Such polymers are formed by the oxidation of heterocycles to give radical cations, which condense with the parent heterocycle. For example, polypyrrole is prepared by oxidation of pyrrole using ferric chloride in methanol:
In March 2021, Columbia University professor Thomas J. Christensen wrote that the cold war between the US and China "is unlikely" in comparison to the original Cold War, citing China's prominence in the "global production chain" and absence of the authoritarianism vs. liberal democracy dynamic. Christensen further advised those concerned about the tensions between the two nations to research China's role in the global economy and its "foreign policy toward international conflicts and civil wars" between liberal and authoritarian forces. In September 2021, former Portuguese defence and foreign minister Paulo Portas described the announcement of the AUKUS security pact and the ensuing unprecedented diplomatic crisis between the signatories (Australia, the United Kingdom, and the United States) and France (which has several territories in the Indo-Pacific) as a possible formal starting point of a new Cold War. On 7 November 2021, President Biden's national security adviser Jake Sullivan stated that the US does not pursue system change in China anymore, marking a clear break from the China policy pursued by previous US administrations. Sullivan said that the US is not seeking a new Cold War with China, but is looking for a system of peaceful coexistence. In November 2021, Hal Brands and Yale professor John Lewis Gaddis wrote in Foreign Affairs that while it was no longer debatable that the United States and China has been entering into their "own new cold war", it was not clear that the world has also been following suit and entering into a new cold war.
==== 10 Man Operational Ration Pack ==== The UK also fields a larger pack of rations intended to feed ten soldiers for 24 hours from centralised but basic preparation; generally similar in content to the single issue ORP but tending to contain larger quantities of food in cylindrical tin cans to be divided up on preparation, rather than individual retort pouches or packets. Even dry materials like sugar or biscuits are often packed in these cans. They contain ingredients for baking bread and tinned food, including vegetables, corned beef and sausages in lard. Also included are chocolate, pre-cooked chicken or beef in gravy and soya mince. Ten boxed one-man ORPs are supplied in larger boxes identical in shape to the single ten-man pack.
After his election in 1994, Nelson Mandela encouraged black South Africans to get behind the previously hated national rugby team, the Springboks, as South Africa hosted the 1995 Rugby World Cup. Prior to the World Cup in 1995, the Springboks were only seeded ninth and were not expected to dethrone the incumbent champions Australia, who had not lost a game in the preceding 12 months. During the tournament, South Africa defeated Australia, Romania, Canada, Western Samoa and France. They then met New Zealand in the 1995 Rugby World Cup Final at Ellis Park Stadium. Springbok captain Francois Pienaar played on in extra-time despite a calf strain and the Springboks secured a three-point victory with a drop goal from Joel Stransky. During the remarkable post-match presentation ceremony, Nelson Mandela presented Pienaar with the Webb Ellis Cup while wearing a Springbok jersey bearing Pienaar's own number 6. During his acceptance speech, Pienaar made it clear that the team had won the trophy not just for the 60,000 fans at Ellis Park, but also for all 43,000,000 South Africans. This was widely seen as a major step in the reconciliation of white and black South Africans; as F.W. de Klerk later put it, "Mandela won the hearts of millions of white rugby fans." Mandela's efforts at reconciliation assuaged the fears of whites, but also drew criticism from more militant blacks. His estranged wife, Winnie, accused the ANC of being more interested in appeasing whites than in helping blacks.
"Seeking to pursue excellence or a personal ideal" "Seeking to use the best in yourself" "Seeking to develop a skill, learn, or gain insight into something" "Seeking to do what you believe in". The study determined that participants derived well-being from eudaimonic pursuits only if their parents had role modeled eudaimonia, but not if their parents had merely verbally endorsed eudaimonia. Studies were also conducted on responsiveness and demandingness. The studies participants were American university undergraduates. The terms are described as follows; responsiveness satisfies the basic psychological need for autonomy. This is relevant to eudaimonia because it supports and implements the values of initiative, effort, and persistence, and integration of one's behaviour's values, and true-self. Autonomy is an important psychological factor because it provides the individual with independence. Demandingness cultivates many of the qualities needed for eudaimonia, including structure, self-discipline, responsibility, and vision. Responsiveness and demandingness are reported to be good aspects of parenting. The studies report both of these qualities as important factors to well-being. The study addressed parenting style by assessing and using adaptions of Baumrind's Parent Behaviour Rating Interview. Adaptions of this interview were made into a seventy-five question based survey; participants answered questions organized into fifteen subscales.
Sources: en.wikipedia.org
== Analysis == Testing for cyanuric acid concentration is commonly done with a turbidometric test, which uses a reagent, melamine, to precipitate the cyanuric acid. The relative turbidity of the reacted sample quantifies the CYA concentration. Referenced in 1957, this test works because melamine combines with the cyanuric acid in the water to form a fine, white precipitate of the insoluble complex melamine cyanurate that causes the water to cloud in proportion to the amount of cyanuric acid in it. More recently, a sensitive method has been developed for analysis of cyanuric acid in urine.
== Market share == While there are many different ways to sequence DNA, only a few dominate the market. In 2022, Illumina had about 80% of the market; the rest of the market is taken by only a few players (PacBio, Oxford, 454, MGI)
In the 1930s and early 1940s, several major federal programs provided some relief to Knoxvillians suffering amidst the Depression. The Great Smoky Mountains National Park, which wealthy Knoxvillians had led the drive to create, opened in 1932. In 1933, the Tennessee Valley Authority (TVA) was established with its headquarters in Knoxville, its initial purpose being to control flooding and improve navigation in the Tennessee River watershed, and provide electricity to the area. During World War II, the construction of Manhattan Project facilities in nearby Oak Ridge brought thousands of federal workers to the area, and helped boost Knoxville's economy.
=== Sjögren syndrome === Sjögren syndrome (SS) is an autoimmune rheumatic disease of the exocrine glands. Increased incidence of SS after childbirth suggests a relationship between SS and pregnancy, and this led to the hypothesis that fetal microchimerism may be involved in SS pathogenesis. Studies showed the presence of Y-chromosome-positive fetal cells in minor salivary glands in 11 of 20 women with SS but in only one of eight normal controls. Fetal cells in salivary glands suggest that they may be involved in the development of SS.
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.
Selank is a synthetic seven-amino-acid peptide modeled on tuftsin, a fragment of the immunoglobulin G heavy chain. It was designed in Russia to combine anxiolytic and immunomodulatory properties in one molecule.