Research chemical raises a handful of sensible questions. This page answers them in order, starting with the fundamentals and moving to applications.
Reviewed 2026-06-07. Anything still debated is marked as such rather than presented as settled.
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.
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.
The compound was designed at the Institute of Molecular Genetics of the Russian Academy of Sciences during the 1980s and 1990s. The stated design goal was to retain the immunomodulatory and central nervous system activity attributed to tuftsin while improving resistance to enzymatic breakdown. Adding a proline-rich tail to the short parent peptide was a deliberate strategy, because proline residues restrict the conformations available to many peptidases. The same laboratory produced Semax, an ACTH fragment analog, and both compounds were developed in parallel as short, enzymatically stabilized peptides intended for intranasal use.
Selank is not a naturally occurring peptide and has no known endogenous counterpart in human physiology. Russian-language sources frequently call it TP-7, while English-language sources use the name Selank almost exclusively. Database indexing is uneven, partly because early reports appeared in regional journals that are not widely cataloged. Some summaries describe the material as a tuftsin analog and others as a synthetic heptapeptide; the labels overlap rather than conflict. Citing the primary sequence resolves ambiguity more reliably than the research or trade name alone.
Selank is a synthetic heptapeptide with the sequence Thr-Lys-Pro-Arg-Pro-Gly-Pro, written TKPRPGP in one-letter notation. Its structure consists of the immunomodulatory tetrapeptide tuftsin, Thr-Lys-Pro-Arg, extended at the carboxyl terminus by a Pro-Gly-Pro segment. The molecular formula is commonly given as C33H57N11O9, corresponding to a monoisotopic mass near 751.4 Da and an average molecular mass near 751.9 Da. All seven residues are proteinogenic amino acids, and the molecule carries no modified side chains or non-natural linkages.
| Property | Value | Notes |
|---|---|---|
| Typical storage temperature | -20 °C or below | For lyophilized powder, long term |
| Common analytical method | Reverse-phase HPLC | Usually paired with mass spectrometry |
| Typical reported purity | At or above 95 percent by area | Research-grade material |
| Aqueous solubility | High | Solutions used in laboratory assays |
| Moisture sensitivity | Hydrolyzes in solution | Aseptic handling reduces degradation |
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.
Selank is a synthetic heptapeptide with the sequence Thr-Lys-Pro-Arg-Pro-Gly-Pro. It was designed at the Institute of Molecular Genetics of the Russian Academy of Sciences as a structural analogue of tuftsin, a naturally occurring tetrapeptide fragment of the immunoglobulin heavy chain. The added Pro-Gly-Pro tail was intended to slow enzymatic degradation and extend biological activity. In Russia it is registered as an anxiolytic nasal preparation, while regulators elsewhere have not approved it for clinical use.
Proposed mechanisms centre on modulation of the GABAergic system, with reports of altered expression of genes related to GABA-A receptor subunits and changed monoamine turnover. Some studies describe inhibition of enkephalinase, the enzyme that degrades endogenous enkephalins, which may prolong opioid peptide signalling. Effects on brain-derived neurotrophic factor and on cytokine expression have also been reported. These findings come largely from animal models and small human studies, and the precise primary target remains unresolved.
Published clinical evidence is limited. Most controlled trials were conducted in Russia, enrolled modest numbers of participants, and appeared in Russian-language journals, which restricts independent verification. Reported outcomes include lower anxiety scores, improved attention and memory measures, and changes in fatigue ratings. Reviews written in English note methodological limitations such as small samples and inconsistent endpoints. Whether the compound produces clinically meaningful benefit relative to established anxiolytics is therefore an open question rather than an established finding.
Flexibility is the anatomical range of movement in a joint or series of joints, and length in muscles that cross the joints to induce a bending movement or motion. Flexibility varies between individuals, particularly in terms of differences in muscle length of multi-joint muscles. Flexibility in some joints can be increased to a certain degree by exercising, with stretching being a common exercise component to maintain or improve flexibility. Limberness is the condition of having flexibility to a positive or superior degree, which is also spoken of as a person having flexibility or being flexible.
==== Social isolation of people with sickle cell disease ==== The deeply rooted stigma of sickle cell disease in society causes families to often hide their family members' sick status for fear of being labelled, cursed, or left out of social events. Sometimes in Uganda, when it is confirmed that a family member has sickle cell disease, intimate relationships with all members of the family are avoided. The stigmatisation and social isolation that people with sickle cell disease tend to experience are often the consequence of popular misconceptions that people with sickle cell disease should not socialise with those free from the disease. This mentality robs people with sickle cell disease of the right to participate in community activities freely like everyone else. SCD-related stigma and social isolation in schools, especially, can make life for young people living with sickle cell disease challenging. For school-aged children living with sickle cell disease, the stigma they face can lead to peer rejection. Peer rejection involves the exclusion from social groups or gatherings. It often leads the excluded individual to experience emotional distress and may result in their academic underperformance, avoidance of school, and occupational failure later in life. This social isolation is also likely to negatively impact people with sickle cell disease's self-esteem and overall quality of life. Mothers of children with sickle cell disease tend to receive disproportionate amounts of stigma from their peers and family members.
Ross (1971), historian and professor at University of Southern California, 2018 Pulitzer Prize for History finalist Roy Rosenzweig (1971), historian and director of the Center for History and New Media at George Mason University Scott Atran (1972), anthropologist; director at Centre National de la Recherche Scientifique and presidential scholar at John Jay College of Criminal Justice Joel Black (1972), literature and film scholar Michael Gerrard (1972), professor at Columbia Law School Jerome Groopman (1972), Harvard Medical School professor and medical writer for The New Yorker Robert Hymes (1972), professor of Chinese history at Columbia University, winner of two Joseph Levenson Book Prizes George Klosko (1972), professor of philosophy at the University of Virginia Mark J. Roe (1972), professor at Harvard Law School John Servos (1972), professor and historian of science; president of the History of Science Society David Stern (1972), professor of Hebrew literature at Harvard University Tom R. Tyler (1972), professor of psychology at Yale Law School Harold Aram Veeser (1972), professor at City College of New York, known for contribution to new historicism Sean Wilentz (1972), historian and winner of the Bancroft Prize; chair of American Studies at Princeton University Angelo Falcón (1973), political scientist, president and founder of the National Institute for Latino Policy Steven Messner (1973), sociologist, professor of the University at Albany, SUNY, former president of the American Society of Criminology William C.
Scarring during healing can create both physical and psychological problems, and is a significant clinical burden. Collagen, for instance, is abnormally organised in scar tissue; collagen in scars is arranged in parallel bundles of collagen fibers, whilst healthy scar free tissue has a "basket weave" structure (Figure 1). The difference in collagen arrangement along with a lack of difference in the dermal tissue when healing has taken place with or without scarring is indicative of regenerative failure of normal skin. Severe scarring resulting from these collagen deposits is known as hypertrophic scarring and is of great concern worldwide with an incidence ranging from 32–72%.
Sources: en.wikipedia.org
==== IV. Gene Delivery through Electrostatic Interactions ==== Microbubbles also serve a non-viral vector for gene transfection through electrostatic bonds between a positively charged microbubble outer shell and negatively charged nucleic acids. The transient pores formed by microbubble collapse allow the genetic material to pass into the target cells in a safer and more specific manner than current treatment methods. Microbubbles have been used to deliver microRNAs, plasmids, small interfering RNA, and messenger RNA.
=== Early studies === Fourteen years after the first publication on its detection in 1973, 12-HHT was reported to stimulate fetal bovine aortic and human umbilical vein endothelial cells to metabolize arachidonic acid to prostaglandin I2 (PGI2 or prostacyclin), a powerful inhibitor of platelet activation and stimulator of vasodilation (see Prostacyclin synthase). 12-HHT did not, however, alter arachidonic acid metabolism in human platelets. Shortly thereafter, 12-HHT was reported to inhibit the chemotaxis-blocking effect of a human monocyte-derived factor on human monocytes. 12-Oxo-HT, the immediate metabolite of 12-HHT, was reported to stimulate the chemotasis of human neutrophils and to inhibit platelet aggregation responses to various agents by stimulating platelets to raise their levels of cyclic adenosine monophosphate (cAMP), an intracellular signal that serves broadly to inhibit platelet activation. These studies were largely overlooked; in 1998 and 2007 publications, for example, 12-HHT was regarded as either inactive or without significant biological activity. Nonetheless, this early work suggested that 12-HHT may serve as a contributor to monocyte- and neutrophil-based inflammatory responses, and that 12-oxo-HT may serve as a counterpoise to platelet aggregation responses elicited or promoted by TXA2.
=== China and India === Imran Ali Sandano of the University of Sindh, Arup K. Chatterjee of the Jindal Global Law School, journalist Bertil Lintner, writer Bruno Maçães, politician-lawyer P. Chidambaram, politician and journalist Sanjay Jha, and some others use the terms like "new cold war" to refer to growing tensions between China and India.
Sources: en.wikipedia.org
==== Approximated wavefunction of the deuteron ==== The deuteron wavefunction must be antisymmetric if the isospin representation is used (since a proton and a neutron are not identical particles, the wavefunction need not be antisymmetric in general). Apart from their isospin, the two nucleons also have spin and spatial distributions of their wavefunction. The latter is symmetric if the deuteron is symmetric under parity (i.e. has an "even" or "positive" parity), and antisymmetric if the deuteron is antisymmetric under parity (i.e. has an "odd" or "negative" parity). The parity is fully determined by the total orbital angular momentum of the two nucleons: if it is even then the parity is even (positive), and if it is odd then the parity is odd (negative). The deuteron, being an isospin singlet, is antisymmetric under nucleons exchange due to isospin, and therefore must be symmetric under the double exchange of their spin and location. Therefore, it can be in either of the following two different states:
5-MAPB, also known as 5-(N-methyl-2-aminopropyl)benzofuran, as well as by nicknames such as "MDMA 2.0" and "Gas Station Molly", is an entactogen of the phenethylamine, amphetamine, and benzofuran families related to MDMA ("Ecstasy"). It is an analogue of MDMA in which one of the oxygen atoms of the benzodioxole ring has been replaced with a carbon atom. The drug is said to have the closest-known effects to MDMA of any other MDMA analogue, but is said to be less stimulating in comparison and to have less comedown and hangover. In addition, it is more potent than MDMA and has a longer duration. The drug acts as a serotonin–norepinephrine–dopamine releasing agent (SNDRA) similarly to MDMA. It is also an agonist of several serotonin receptors, including the serotonin 5-HT1B, 5-HT2A, 5-HT2B, and 5-HT2C receptors. Some notable analogues of 5-MAPB besides MDMA include other benzofurans like 5-APB, 5-MAPDB, and 6-MAPB. 5-MAPB was first encountered as a novel designer drug in 2013 and was described in the scientific literature in 2014. It is said to have been first synthesized in 2009. The drug has been patented by Tactogen for potential use as a medicine to treat psychiatric disorders. It is openly sold as a legal recreational drug in the United States. In addition to its use by itself, 5-MAPB is used as a component of the more closely MDMA-mimicking Borax combo.
=== Age === Historically, obesity primarily affected adults, but childhood obesity has grown significantly in recent decades. From the mid-1980s to the mid-2010s, obesity roughly doubled among U.S. children ages 2 to 5 and roughly tripled among young people over the age of 6. Overall, obesity in the United States peaks during the middle aged years. During the period 2015–16, the prevalence of obesity among adults aged 20–39 was 35.7%, among those aged 40–59, 42.8%, and among those 60 and over, 41.0%.
Sources: en.wikipedia.org
The most common approach combines reverse-phase liquid chromatography with mass spectrometry. Chromatography separates the components while mass spectrometry confirms the molecular mass. Peptide sequencing or tandem mass analysis can further verify the amino acid order.
Lyophilized powder is usually kept frozen and protected from moisture. Solutions are less stable and are often used promptly or divided into aliquots to avoid repeated freeze-thaw cycles. Exact shelf-life values depend on purity and handling.
No. A purity figure derived from chromatographic area does not prove the amino acid sequence. Identity requires an orthogonal method such as mass spectrometry or sequencing. Truncated or isomerized peptides can co-elute with the target compound.
The sequence is Thr-Lys-Pro-Arg-Pro-Gly-Pro, written TKPRPGP in one-letter code. It combines the tetrapeptide tuftsin with a carboxyl-terminal Pro-Gly-Pro extension. This full sequence identifies the molecule more precisely than the research name.