Everything below concerns intranasal delivery. We keep the language plain, cite what the science says, and separate well-supported claims from open questions.
Last reviewed on 2026-08-01. Where a claim depends on a specific study, the study is described rather than over-claimed.
Selank is a synthetic heptapeptide with the sequence Thr-Lys-Pro-Arg-Pro-Gly-Pro. It was designed as a stabilized analogue of tuftsin, a naturally occurring tetrapeptide fragment derived from the immunoglobulin heavy chain. The additional Pro-Gly-Pro segment at the carboxyl terminus is intended to slow enzymatic cleavage. The compound is usually described in the literature as a synthetic peptide with anxiolytic and cognitive-related activity, a label that reflects a research context rather than an approved therapeutic category.
Most published work on selank originates from a small number of research groups in the Russian Federation. A large share of that record appears in Russian-language journals, which limits access for readers who rely on English-indexed databases. Independent replication by laboratories outside the original research network is sparse in publicly available sources. This concentration of origin and language is a frequently noted feature when the compound is summarized in broader reviews of synthetic peptides.
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.
Animal studies have examined behaviour in tests of anxiety, memory retention and stress response, and several report changes in neurotrophic or neurotransmitter-related markers. The human evidence base is much smaller, consisting mainly of short trials conducted in Russia with limited reporting in English-language journals. Sample sizes are modest and outcome measures vary between studies, so the findings are best described as preliminary. Independent replication under modern trial standards has not been widely reported.
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.
| Property | Value | Notes |
|---|---|---|
| Molecular formula | C33H57N11O9 | Derived from the seven-residue sequence |
| Molecular weight | About 751.9 g/mol | Average mass; the monoisotopic value is slightly lower |
| Residue count | Seven amino acids | Thr-Lys-Pro-Arg-Pro-Gly-Pro |
| Parent compound | Tuftsin (Thr-Lys-Pro-Arg) | Selank extends tuftsin at the C-terminus |
| Compound class | Synthetic short peptide | Studied in a research setting; not a licensed drug in most markets |
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.
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.
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.
Purity assessment relies mainly on reverse-phase high-performance liquid chromatography with ultraviolet detection. Because the peptide lacks a strong chromophore, detection often uses backbone absorbance near 214 nm. Identity is confirmed by mass spectrometry, typically electrospray ionization or matrix-assisted laser desorption, comparing the measured mass against the expected value. Amino acid analysis can verify composition after acid hydrolysis. Diastereomer content and residual counterions are reported less often, although both can influence biological assays.
Lyophilized material is generally stable for extended periods when kept dry at or below minus twenty degrees Celsius. Working solutions are less stable, and common practice is to aliquot and freeze them so that repeated freeze-thaw cycles are avoided. Aqueous solutions are sensitive to pH extremes and to microbial growth, so short-term storage at refrigerator temperature is typical. Oxidation and hydrolysis are the principal degradation routes. Reconstitution with sterile water or a mild buffer is standard, and solutions should be protected from light.
Regulatory treatment varies by jurisdiction. In Russia the compound is a registered prescription product, while in the European Union and the United States it is generally handled as a research chemical without a marketing authorization. Suppliers therefore operate outside pharmaceutical oversight, and buyers rely on supplier documentation for purity and identity claims. Chain of custody and third-party testing are the main verification tools. Analysts note that the absence of a pharmacopoeial monograph for research-grade material limits standardization across vendors.
Development took place at the Institute of Molecular Genetics of the Russian Academy of Sciences, where a series of short peptides were designed in the 1980s and 1990s. Selank was selected from variants of tuftsin that showed resistance to plasma peptidases. Russian regulatory approval covers it as an anxiolytic agent given intranasally. Outside that market the compound is normally handled as a research chemical rather than a medicine, and no widely recognised international pharmacopoeial monograph exists. The name Selank is a coined trade designation rather than a systematic chemical name.
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.
=== Other === Flunitrazepam impairs cognitive functions. This may appear as lack of concentration, confusion and anterograde amnesia—the inability to create memories while under the influence. It can be described as a hangover-like effect which can persist to the next day. It also impairs psychomotor functions similar to other benzodiazepines and nonbenzodiazepine hypnotic drugs; falls and hip fractures were frequently reported. The combination with alcohol increases these impairments. Partial, but incomplete tolerance develops to these impairments. Other adverse effects include:
The amplitude of the wave is proportional to the measuring potential difference at the frequency of the vibration, efficiently filtered by a lock-in amplifier that boosts probe's sensitivity. The vibrating ion-selective microelectrode was first used in 1990 to measure calcium fluxes in various cells and tissues. The ion-selective microelectrode is an adaptation of the glass microelectrode, where an ion-specific liquid ion exchanger (ionophore) is tip-filled into a previously silanized (to prevent leakage) microelectrode. Also, the microelectrode vibrates at low frequencies to operate in the accurate self-referencing mode. Only the specific ion permeates the ionophore, therefore the voltage readout is proportional to the ion concentration in the measuring condition. Then, flux is calculated using the Fick's first law. Emerging optic-based techniques, for example, the pH optrode (or optode), which can be integrated into a self-referencing system may become an alternative or additional technique in bioelectricity laboratories. The optrode does not require referencing and is insensitive to electromagnetism simplifying system setting up and making it a suitable option for recordings where electric stimulation is simultaneously applied. Much work to functionally study bioelectric signaling has made use of applied (exogenous) electric currents and fields via DC and AC voltage-delivering apparatus integrated with agarose salt bridges. These devices can generate countless combinations of voltage magnitude and direction, pulses, and frequencies.
In Chennai, Tamil Nadu CMDA authorities placed a seal on the massive warehouse spreading across 7 acres that had reportedly been built for one of the world's leading multinational retail giants, Wal-mart. Domestic retail players like Future Retail, Avenues Supermarket and Aditya Birla Fashion and Retail has been slowly growing, making entering the country more difficult for MNCs like Walmart and Carrefour. On 28 August 2019, Indian union cabinet approved proposals to ease local sourcing norms as applicable to SBRT.
Sources: en.wikipedia.org
=== Optical isomerism === Optical isomerism occurs when a complex is not superimposable with its mirror image. It is so called because the two isomers are each optically active, that is, they rotate the plane of polarized light in opposite directions. In the first molecule shown, the symbol Λ (lambda) is used as a prefix to describe the left-handed propeller twist formed by three bidentate ligands. The second molecule is the mirror image of the first, with the symbol Δ (delta) as a prefix for the right-handed propeller twist. The third and fourth molecules are a similar pair of Λ and Δ isomers, in this case with two bidentate ligands and two identical monodentate ligands.
Played in his 52nd Masters Tournament at Augusta National in April 2009, extending his record of for most Masters appearances Inducted into the African American Sports Hall of Fame in May 2007, with Lifetime Achievement Award Has played in a record 46 consecutive British Open Championships, winning 3 times over 3 decades. Stars with Camilo Villegas in a MasterCard "priceless foursome" television commercial launched during the U.S. Open in June 2009 In November 2009 he was awarded the inaugural Breeders Cup "Sports and Racing Excellence Award" at Santa Anita Park in California which honours owners and breeders of thoroughbred race horses. Was inducted into the Asian Pacific Golf Hall of Fame with Jack Nicklaus in 2011 at a ceremony in Pattaya, Thailand. In December 2011, Gary Player Design was selected amongst the finalists to design the golf course for the 2016 Olympic Games in Rio de Janeiro He received the PGA Tour Lifetime Achievement Award at The Players Championship in May 2012. The first international person to receive this accolade. Received the 2020 GCSAA Old Tom Morris Award from the Golf Course Superintendents Association of America Received the Presidential Medal of Freedom on 7 January 2021 from then President Donald Trump. With the death of Jack Burke Jr., Player becomes the oldest living Masters champion.
No chronology will be observed here, nor is one necessary. Hence each reader will put together the book for himself, as in a game of dominoes or cards, and, as with a mirror, he will get out of this dictionary as much as he puts into it, for you [...] cannot get more out of the truth than what you put into it. The book comes in two different editions, one "male" and one "female", which differ in only a critical passage in a single paragraph. In 1984, Pavić stated that the Khazars were a metaphor for a small people surviving in between great powers and great religions. In Yugoslavia, Pavić stated five years later, Serbs recognized their own fate; it was the same in Slovenia and elsewhere, a schoolbook on survival. The same in Hungary and Czechoslovakia, and on and on. A French critic said, 'We are all Khazars in the age of nuclear threat and poisoned environment.' A ballet adaption of the Dictionary of the Khazars was staged at Madlenianum Opera and Theatre. A play based on the novel has also been staged in the New Riga Theatre.
== Synthesis == In the radiopharmaceutical industry, fluorine-18 is made using either a cyclotron or linear particle accelerator to bombard a target, usually of natural or enriched [18O]water with high energy protons (typically ~18 MeV). The fluorine produced is in the form of a water solution of [18F]fluoride, which is then used in a rapid chemical synthesis of various radiopharmaceuticals. This must be done after the fluorine is produced, as chemical bonds would be destroyed by the production (radiolysis).
Sources: en.wikipedia.org
Territories have long been shared between peoples, and individuals have often identified themselves within networks of relationships rather than as subjects of a particular state sovereign." Basing citizenship off the Dawes Rolls and other rolls is what scholar Fay A. Yarbrough calls "dramatically different from older conceptions of Cherokee identity based on clan relationships, in which individuals could be fully Cherokee without possessing any Cherokee ancestry" and that by the tribe later "developing a quantifiable definition of Cherokee identity based on ancestry", this "would dramatically affect the process of enrollment late in the nineteenth century and the modern procedure of obtaining membership in the Cherokee Nation, both of which require tracing an individuals' lineage to a 'Cherokee by blood.'" Thus, the Dawes Roll itself still upholds "by blood" language and theory. Mark Edwin Miller acknowledges in his work that many of descent people left the tribes and "assimilated into existing, non-tribal (if also nonwhite) communities," and thus, without a tribe, cannot be recognized by the BIA. Miller also states that even "so-called purely 'descendancy' tribes such as the Five Tribes with no blood quantum requirement jealously guard some proven, documentary link by blood to distant ancestors. More than any single BIA requirement, however, this criterion has proven troublesome for southeastern groups [seeking federal recognition] because of its reliance on non-Indian records and the confused (and confusing) nature of surviving documents."
Bavington, Dean L. Y. Managed Annihilation: An Unnatural History of the Newfoundland Cod Collapse (University of British Columbia Press; 2010) 224 pages. Links the collapse of Newfoundland and Labrador cod fishing to state management of the resource. Cobb, John N. (1916). Pacific Cod Fisheries. Bureau of Fisheries Document. Vol. 830. Washington, DC: Government Printing Office. OCLC 14263968. Greenberg, Paul (2010). Four Fish: The Future of the Last Wild Food. New York: Penguin Press. ISBN 978-1-59420-256-8. OCLC 813929026. Mark Kurlansky (1997). Cod: A Biography of the Fish That Changed the World. Shields, Edward (2001). Salt of the Sea: The Pacific Coast Cod Fishery and the Last Days of Sail. Lopez Island, Wash.: Heritage House. ISBN 978-1-894384-35-3.
John Stewart was chosen by Bruce Timm as the Green Lantern in the 2001 television cartoon Justice League. As the series creator, Timm changed the character into a "no-nonsense" former U.S. Marine member. Timm gave him a military background because of his disinterest of portraying him "to the militant Black Panther Party from the early '70s" because he viewed it as currently being irrelevant, and also because he wanted his ring to only produce beams instead of constructs. Geoff Johns incorporated the marine background into the comic version of the character in 2007's Green Lantern vol. 4 #26.
Sources: en.wikipedia.org
Selank is a synthetic heptapeptide with the sequence Thr-Lys-Pro-Arg-Pro-Gly-Pro, designed as a metabolically stabilized analogue of the endogenous tetrapeptide tuftsin. It has been studied mainly against anxiety-related and cognitive endpoints rather than as an approved medicine in most jurisdictions.
Tuftsin contains four residues, while selank carries an additional Pro-Gly-Pro segment at the carboxyl end. That extension is intended to reduce enzymatic cleavage. Comparative pharmacokinetic data in humans remain limited.
No single receptor target is widely accepted as the definitive mediator of the reported effects. Proposed contributors include GABAergic modulation, shifts in monoamine turnover, and altered neuropeptide degradation. The mechanism is treated in the literature as unresolved.
Most published work uses intranasal application, either as drops or as a nasal spray. Injection routes appear in a smaller set of animal experiments. Oral use is uncommon in the literature because peptide breakdown and poor absorption limit this route.