elevated plus maze is one of those subjects where the details matter more than the headlines. This page pulls together the background, the mechanisms, and the practical points readers ask about most.
Updated 2025-10-16. Numbers and descriptions here follow the published literature rather than marketing material.
Enzymatic stability motivates the extra three residues at the carboxyl end. Native tuftsin is cleaved quickly by circulating aminopeptidases and carboxypeptidases, which limits its duration of action and its usefulness as a tool compound. Extending the chain with proline-rich segments is a common design tactic because proline constrains the backbone and slows proteolysis. The same Pro-Gly-Pro motif appears in other Russian-developed peptides of the era. Whether the full seven-residue chain is required for activity, or whether it acts mainly as a prodrug releasing tuftsin, remains unresolved.
Selank is a synthetic heptapeptide with the sequence Thr-Lys-Pro-Arg-Pro-Gly-Pro. Its four N-terminal residues reproduce tuftsin, a tetrapeptide fragment of the immunoglobulin heavy chain, while the C-terminal Pro-Gly-Pro extension is a synthetic addition. The peptide has a molecular mass near 752 daltons and carries a net positive charge at physiological pH because of the arginine and lysine side chains. Published indexes list it under the name Selank and the sequence abbreviation TKPRPGP. Solid-phase peptide synthesis is the standard production route for research quantities.
Reverse-phase high-performance liquid chromatography with ultraviolet detection near 214 nanometres is the standard purity method. Mass spectrometry, typically electrospray ionisation, confirms identity through the expected mass-to-charge pattern. Amino acid analysis can verify composition independently. Chiral purity requires separate techniques such as derivatisation followed by chromatographic separation, and such data are rarely reported for research-grade material.
Quantification in biological matrices relies on liquid chromatography coupled to tandem mass spectrometry with stable-isotope internal standards. Low plasma concentrations and adsorption to container surfaces both complicate measurement. Solid-phase extraction is often needed to reduce matrix interference before injection. Reported limits of quantification differ widely between laboratories, which makes direct comparison of pharmacokinetic results difficult and limits meta-analysis.
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.
| Property | Value | Notes |
|---|---|---|
| Chemical class | Synthetic heptapeptide | Tuftsin analogue with a C-terminal Pro-Gly-Pro tail |
| Amino acid sequence | Thr-Lys-Pro-Arg-Pro-Gly-Pro | Abbreviated TKPRPGP in most catalogues |
| Molecular mass | About 752 Da | Value for the free peptide |
| Solubility | Freely soluble in water | Aqueous solutions are kept cold and used promptly |
| Typical storage | -20 °C, dry, protected from light | Applies to the lyophilised powder before reconstitution |
Outside its country of origin the compound is generally handled as a research chemical rather than an approved medicine. No regulatory approval from the United States Food and Drug Administration or the European Medicines Agency has been granted for human use. Identity and purity are normally checked by reverse-phase high-performance liquid chromatography, with mass spectrometry used to confirm the molecular mass. Lyophilised material is stored cold and desiccated, and repeated freeze-thaw cycles are avoided.
Published work on this peptide almost always uses intranasal delivery, with drops or a spray applied to the nasal mucosa. Some animal experiments have used subcutaneous or intraperitoneal injection, and a smaller number have compared routes directly. Oral administration is not a focus of the literature, because short peptides of this size are broken down by digestive enzymes and cross intestinal barriers poorly. How much of an intranasal dose reaches the bloodstream intact in humans remains an open question.
Clinical evidence comes mainly from small studies conducted in Russia, several of which were open-label or lacked robust blinding. Reported outcomes include lower anxiety scores, changes in attention measures, and effects on asthenic states following illness. Sample sizes are typically in the tens of participants, and independent replication outside the region is scarce. Reviews published in English generally note the limited methodological quality of the underlying trials. Whether the compound produces clinically meaningful effects under rigorous conditions remains unresolved.
Proposed mechanisms center on modulation of the GABA system, but no single molecular target has been confirmed. Rodent studies report changes in GABA-A receptor expression and in the turnover of serotonin, dopamine, and norepinephrine in several brain regions. Increases in brain-derived neurotrophic factor and its receptor have also been described after repeated administration. These findings come largely from animal models, and the degree to which they describe human neurochemistry remains an open question. The mechanism is best characterized as multi-system and not fully resolved.
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.
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.
== Bibliography == Antoni Czubiński, Powstanie Wielkopolskie 1918–1919. Geneza-charakter-znaczenie, Poznań 1978 Antoni Czubiński, Rola Powstania Wielkopolskiego w walce narodu polskiego o powstrzymanie niemieckiego >parcia na wschód<, Przegląd Zachodni 1968, nr 5–6 A. Czubiński, Z.Grot, B.Miśkiiewcz, Powstanie Wielkopolskie 1918–1919. Zarys dziejów, Warszawa 1978 K. Dembski, Wielkopolska w początkach II Rzeczypospolitej. Zagadnienia prawno-ustrojowe, Poznań 1972 Roman Dmowski, Polityka polska i odbudowanie państwa 1925 Z. Grot (ed.), Powstanie wielkopolskie 1918–1919, Poznań 1968 Z. Grot, I. Pawłowski, M. Pirko, Wielkopolska w walce o niepodległość 1918–1919. Wojskowe i polityczne aspekty Powstania Wielkopolskiego, Warszawa 1968 P. Hauser, Niemcy wobec sprawy polskiej X 1918–VI 1919, Poznań 1984 K. Kandziora, Działalność POW w Poznaniu. Przyczynek do historii Polskiej Organizacji Wojskowej zaboru pruskiego w latach 1918–1919, Warszawa 1939 S. Kubiak, Niemcy a Wielkopolska 1918–1919, Poznań 1969 Joseph Lamia: Der Aufstand in Posen (The Uprising in Poznan). Berlin 1919 (in German). Materiały Sesji Naukowej z okazji 50-lecia Powstania Wielkopolskiego 1918/1919, Zaszyty Naukowe UAM 1970, Historia t.10 Witold Mazurczak, Anglicy i wybuch powstania wielkopolskiego. Z dziejów genezy brytyjskiej misji płka H.H.Wade'a w Polsce, [in:] Antoni Czubiński (ed.), Polacy i Niemcy. Dziesięć wieków sąsiedztwa, PWN, Warszawa 1987 Janusz Pajewski, Rodział XXII.
Drugs continue to be taken off the market due to late discovery of hepatotoxicity. Due to its unique metabolism and close relationship with the gastrointestinal tract, the liver is susceptible to injury from drugs and other substances. 75% of blood coming to the liver arrives directly from gastrointestinal organs and the spleen via portal veins that bring drugs and xenobiotics in near-undiluted form. Several mechanisms are responsible for either inducing hepatic injury or worsening the damage process. Many chemicals damage mitochondria, an intracellular organelle that produces energy. Its dysfunction releases excessive amount of oxidants that, in turn, injure hepatic cells. Activation of some enzymes in the cytochrome P-450 system such as CYP2E1 also lead to oxidative stress. Injury to hepatocyte and bile duct cells lead to accumulation of bile acid inside the liver. This promotes further liver damage. Non-parenchymal cells such as Kupffer cells, collagen-producing stellate cells, and leukocytes (i.e. neutrophil and monocyte) also have a role in the mechanism.
The 1970s saw a shift in audience tastes to high concept films, with five such films made by either George Lucas or Steven Spielberg topping the chart during the 1980s. The 21st century has seen an increasing dependence on franchises and adaptations, with the box-office dominance of films based on pre-existing intellectual property at record levels. Steven Spielberg (1975, 1981, 1982, 1989 and 1993) and Cecil B. DeMille (1932, 1947, 1949, 1952 and 1956) tie as the most represented directors on the chart with five films apiece occupying the annual top spot. William Wyler (1942, 1946, 1959 and 1968) and James Cameron (1991, 1997, 2009 and 2022) are each represented by four films, whilst D. W. Griffith (1915, 1916 and 1920), George Roy Hill (1966, 1969 and 1973) and the Russo brothers (2016, 2018 and 2019) all feature heavily with three films apiece. George Lucas directed three chart-toppers in 1977, 1999 and 2005, but also served in a strong creative capacity as a producer and writer in 1980, 1981, 1983, and 1989 as well. The following directors have also all directed two films on the chart: Frank Lloyd, King Vidor, Frank Capra, Michael Curtiz, Leo McCarey, Alfred Hitchcock, David Lean, Stanley Kubrick, Guy Hamilton, Mike Nichols, William Friedkin, Peter Jackson, Gore Verbinski, and Michael Bay; Mervyn LeRoy, Ken Annakin and Robert Wise are each represented by one solo credit and one shared credit, and John Ford co-directed two films.
== Properties and applications == Cyclic peptides tend to be extremely resistant to the process of digestion, making them of interest to scientists working on novel oral medications. Examples include:
Sources: en.wikipedia.org
== Contraindications == The varicella vaccine is not recommended for seriously ill people, pregnant women, people who have tuberculosis, people who have experienced a serious allergic reaction to the varicella vaccine in the past, people who are allergic to gelatin, people allergic to neomycin, people receiving high doses of steroids, people receiving treatment for cancer with x-rays or chemotherapy, as well as people who have received blood products or transfusions during the past five months. Additionally, the varicella vaccine is not recommended for people who are taking salicylates (e.g. aspirin). After receiving the varicella vaccine, the use of salicylates should be avoided for at least six weeks. The varicella vaccine is also not recommended for individuals who have received a live vaccine in the last four weeks, because live vaccines that are administered too soon within one another may not be as effective. It may be usable in people with HIV infections who have a good blood count and are receiving appropriate treatment. Specific antiviral medication, such as acyclovir, famciclovir, or valacyclovir, are not recommended 24 hours before and 14 days after vaccination.
Sulfuric acid is a very important commodity chemical, and a nation's sulfuric acid production was as recently as 2002 believed to be a good indicator of its industrial strength. World production in the year 2004 was about 180 million tonnes, with the following geographic distribution: Asia 35%, North America (including Mexico) 24%, Africa 11%, Western Europe 10%, Eastern Europe and Russia 10%, Australia and Oceania 7%, South America 7%. World production in 2022 was estimated at 260 million tonnes. As of the late 20th century, most of the produced amount (≈60%) was consumed for fertilizers, particularly Superphosphates, ammonium phosphate and Ammonium sulfates. About 20% is used in chemical industry for production of detergents, synthetic resins, dyestuffs, pharmaceuticals, petroleum catalysts, insecticides and antifreeze, as well as in various processes such as oil well acidicizing, aluminium reduction, paper sizing, and water treatment. About 6% of uses are related to pigments and include paints, enamels, printing inks, coated fabrics and paper, while the rest is dispersed into a multitude of applications such as production of explosives, cellophane, acetate and viscose textiles, lubricants, non-ferrous metals, and batteries. Sulfuric acid is used as a consumable for the extraction of copper from oxides in leaching piles. Chile, the world's leading producer of copper, required sulfuric acid in about 20% of its copper production as of 2026.
Botha wanted all the Cuban military personnel to be withdrawn, and over a period of twelve months rather than three years. He also countered that the Namibian independence process could only take place once the Cuban withdrawal was initiated. The Lusaka Accords were abandoned in the wake of Operation Argon, a failed sabotage mission carried out by South African special forces in Angola's oil-rich Cabinda exclave. Four years of military escalation and massive defence expenditures had a drastic impact on Angola's state finances, which were only being balanced by petroleum revenue. The largest oil refinery in the country was located on the Cabindan coast and operated by a US firm, Gulf Oil, under the auspices of the Cabina-Gulf Oil National Petroleum Company of Angola (SONAGOL). By 1984 Gulf had invested over 1.3 billion dollars in its Cabinda operation, which was exporting 165,495 barrels of oil per day. At the time, the revenue from the Gulf refinery generated 90% of Angola's foreign exchange. The Reagan administration separated its political positions on Angola from its position on SONAGOL, with Crocker hoping that American multinational companies in general, and Gulf in particular, would be a moderating force on the Marxist government. South Africa had noted the critical importance of the refinery's contribution to the FAPLA war effort and had begun investigating ways to disrupt it without incurring the ire of the US, which would have to react if American commercial interests were threatened.
Another potential strategy that can facilitate rapid assembly and enhance stability of DNA bricks is the use of the kinetically interlocking multiple-unit (KIMU) strategy. This strategy was used to determine if multiple unit-DNA (MUD) strands could improve structural stability and accelerate the annealing process for medium to long length DNA strands compared to the traditional short-strand DNA brick assemblies. The KIMU theory suggests that increasing the number of noncovalent units can improve the stability of DNA assembly, create DNA bricks with lengths of ~50 nucleotides, and increase collision between DNA bricks. The MUD assemblies increased the local concentration of nucleotide units and enabled well-assembled DNA structures to recover more readily through kinetic interlocking after dissolution. This interlocking, facilitated by the interaction among multiple units, enhanced the stability of the previous assembly composed entirely of short DNA strands, offering an alternative strategy to fabricate longer but stable DNA structures.
== External links == Media related to Protons at Wikimedia Commons Particle Data Group at LBL Large Hadron Collider Eaves, Laurence; Copeland, Ed; Padilla, Antonio (Tony) (2010). "The shrinking proton". Sixty Symbols. Brady Haran for the University of Nottingham. MIT proton visualization project: Inside the Proton, the 'Most Complicated Thing You Could Possibly Imagine', Quanta Magazine, Oct 19 2022 Visualizing the Proton, Arts at MIT, 2022
Sources: en.wikipedia.org
Black Mesa is a third-party remake of the original Half-Life, developed and published by Crowbar Collective and made in the Source engine. Originally published as a free mod in September 2012, it was approved by Valve for a commercial release. It was fully released on March 6, 2020, for Windows and Linux. It was praised by reviewers, who likened it to an official Valve game. On the review aggregator OpenCritic, Black Mesa had an average 87/100 review score with 100% approval rating based on 14 reviews.
The main steroid hormones, testosterone, estradiol, and progesterone as well as prolactin play important physiological functions in puberty. The production of gonadal steroids in females starts with production of testosterone, which is typically quickly converted to estradiol inside the ovaries. However the rate of conversion from testosterone to estradiol (driven by FSH/LH balance) during early puberty is highly individual, resulting in very diverse development patterns of secondary sexual characteristics. Production of progesterone in the ovaries begins with the development of ovulatory cycles in females (during the lutheal phase of the cycle), before puberty low levels of progesterone are produced in the adrenal glands of both males and females. Estradiol levels rise earlier and reach higher levels in women than in men. While estradiol promotes growth of the breasts and uterus, it is also the principal hormone driving the pubertal growth spurt and epiphyseal maturation and closure.
the Emil Fischer Medal of the Society of German Chemists (1922), the Cannizaro Prize of the Royal Academy of Science in Rome (1938), the Copernicus Prize of the University of Konigsberg (1941), the Gothenius Medal of the Akademie der Naturforscher (1943), the Max Planck Medal of the German Physical Society, with Lise Meitner (1949), the Goethe Medal of the city of Frankfurt-on-the-Main (1949), the Golden Paracelsus Medal of the Swiss Chemical Society (1953), the Faraday Lectureship Prize with Medal from the Royal Society of Chemistry (1956), the Grotius Medal of the Hugo Grotius Foundation (1956), the Wilhelm Exner Medal of the Austrian Industry Association (1958), the Helmholtz Medal of the Berlin-Brandenburg Academy of Sciences and Humanities (1959), and the Harnack medal in Gold from the Max Planck Society (1959).
The maximum yield in such kinetic resolutions is 50%, since a yield of more than 50% means that some of wrong isomer also has reacted, giving a lower enantiomeric excess. Such reactions must therefore be terminated before equilibrium is reached. If it is possible to perform such resolutions under conditions where the two substrate- enantiomers are racemizing continuously, all substrate may in theory be converted into enantiopure product. This is called dynamic resolution. In biocatalyzed asymmetric synthesis, a non-chiral unit becomes chiral in such a way that the different possible stereoisomers are formed in different quantities. The chirality is introduced into the substrate by influence of enzyme, which is chiral. Yeast is a biocatalyst for the enantioselective reduction of ketones.
=== Former commissioners === David Gallop was the initial chief executive officer of the restructured ARL Commission. He was previously the CEO of the NRL and his contract extension to become inaugural ARL CEO was a condition placed by News Limited with the ARL. On 5 June 2012 the ARL announced Gallop's departure from the CEO position and that he would take up a position at the FFA in 2013. David Smith was announced as the new ARL CEO in November 2012, taking charge on 1 February 2013.
Sources: en.wikipedia.org
Selank is a seven-amino-acid peptide built from the tuftsin sequence plus a Pro-Gly-Pro tail. It is produced by chemical synthesis rather than extracted from a natural source. The free peptide is usually supplied as a lyophilised powder or in an aqueous formulation.
Tuftsin is a natural tetrapeptide derived from the Fc portion of immunoglobulin G. Selank retains that tetrapeptide at its N-terminus and adds three residues to improve resistance to enzymatic breakdown. The relationship is structural, and the two molecules are not interchangeable in experimental work.
It holds a product registration in Russia for intranasal use as an anxiolytic. Registrations of that kind are not automatically accepted by regulators elsewhere. In most other countries it is treated as an unapproved substance or a research material.
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.