Heptapeptide 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 2025-12-14. Numbers and descriptions here follow the published literature rather than marketing material.
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.
Pharmacokinetic data are limited. Like most short peptides, Selank is vulnerable to plasma and tissue peptidases, and its measured half-life in circulation is short, on a minutes scale. The Pro-Gly-Pro tail slows this degradation but does not eliminate it. Intranasal administration is the route described in most reports, with absorption through the nasal mucosa and a hypothesized path into the central nervous system that avoids the blood-brain barrier. Direct measurements of human brain exposure are unavailable, so distribution claims rest on inference from animal work.
Naming for this compound is not fully standardised in English sources. The spelling Selanc appears in some transliterations, and catalogue entries may instead list the peptide sequence itself as the identifier. Reference material sometimes groups it with other short synthetic peptides studied for behavioural effects, which can create confusion when citations are compared. Distinguishing the exact sequence from related tuftsin analogues is therefore a practical first step when reviewing any dataset or specification sheet.
Selank is a synthetic heptapeptide with the sequence Thr-Lys-Pro-Arg-Pro-Gly-Pro, frequently abbreviated as TKPRPGP. It was designed as a structural analogue of tuftsin, a naturally occurring tetrapeptide released by enzymatic cleavage of the immunoglobulin heavy chain. The two additional proline residues at the C-terminal end extend the parent chain and change how the molecule behaves in solution. The free peptide has a calculated molecular mass of approximately 751.9 g/mol and is generally supplied as a lyophilised white to off-white powder.
| Property | Value | Notes |
|---|---|---|
| Route studied | Intranasal | Predominant route in published reports |
| Circulation stability | Short, minutes scale | Peptidases cleave it; the tail slows the process |
| Analytical method | RP-HPLC with mass spectrometry | Used for identity and purity assessment |
| Reported outcome domains | Anxiety and cognitive measures | Derived from small, mostly regional trials |
| Regulatory status | Marketed in Russia | Availability outside that market is limited |
Reported activity for Selank centers on anxiolytic and nootropic effects. Russian clinical reports describe use in anxiety and in cognitive or attention-related complaints. Most of this evidence comes from studies conducted by the same research groups that developed the peptide. Independent replication in other countries remains limited, and no major Western regulatory agency has approved the compound for any indication. The gap between local reports and external verification is a recurring point in discussions of the peptide.
Tuftsin, the parent structure, is a naturally occurring immunomodulatory tetrapeptide released from the Fc region of immunoglobulin G by spleen enzymes. Selank extends this four-residue sequence with three additional amino acids. The stated rationale is that the added tail slows enzymatic breakdown and may influence receptor interactions. How the full heptapeptide behaves at the molecular level is not firmly established, and proposed mechanisms often involve indirect modulation of neurotransmitter or immune signaling rather than a single defined target.
Selank is a synthetic heptapeptide developed in Russia. Its sequence is Thr-Lys-Pro-Arg-Pro-Gly-Pro, a seven-residue chain built around the natural tetrapeptide tuftsin. Researchers at the Institute of Molecular Genetics of the Russian Academy of Sciences first described the compound in the mid-1990s. The design combined the tuftsin core with an added Pro-Gly-Pro tail, a modification intended to extend the molecule's stability in biological fluids. Published work on the peptide has appeared mainly in Russian-language journals.
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.
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.
Pure culture yeasts that are grown in a lab are often freeze dried and packaged for commercial use. Prior to their addition into must, these yeasts need to be re-hydrated in "starter cultures" that must be carefully monitored (particularly in regards to temperature) to ensure that the yeast cells are not killed off by cold shock. Ideally winemakers want to add enough inoculum to have a viable cell population density of 5 million cells per milliliter. The exact amount of freeze-dried culture varies by manufacturer and strain of yeast but it is often around 1 gram per gallon (or 25 grams per 100 liters). Wines that could have potentially problematic fermentation (such as high sugar level late harvest or botryized wines) may have more yeast added. Similarly, re-hydration procedures will also vary depending on the manufacturer and winery. Yeast is often inoculated in a volume of water or grape must that is 5–10 times the weight of the dry yeast. This liquid is often brought to temperature of 40 °C (104 °F) prior to the introduction of the yeast (though some yeast strains may need temperatures below 38 °C (100 °F)) to allow the cells to disperse easily rather than clump and sink to the bottom of the container. The heat activation also allows the cells to quickly reestablish their membrane barrier before soluble cytoplasmic components escape the cell. Re-hydration at lower temperatures can greatly reduce the viability of the yeast with up to 60% cell death if the yeast is re-hydrated at 15 °C (59 °F).
=== Inscribed hexagon === If a tangential hexagon is formed by drawing three segments tangent to a triangle's incircle and parallel to a side, so that the hexagon is inscribed in the triangle with its other three sides coinciding with parts of the triangle's sides, then
===== Personal training to increase happiness ===== The easiest and best possible way to increase one's happiness is by doing something that increases the ratio of positive to negative emotions. Contrary to some beliefs, in many scenarios, people are actually very good at determining what will increase their positive emotions. There have been many techniques developed to help increase one's happiness. A first technique is known as the "Sustainable Happiness Model (SHM)." This model proposes that long-term happiness is determined upon: (1) one's genetically determined set-point, (2) circumstantial factors, and (3) intentional activities. Lyubomirsky, Sheldon and Schkade suggest to make these changes in the correct way in order to have long-term happiness. Another suggestion of how to increase one's happiness is through a procedure called "Hope Training." Hope Training is primarily focused on hope due to the belief that hope drives the positive emotions of well-being. This training is based on the hope theory, which states that well-being can increase once people have developed goals and believe themselves to achieve those goals. One of the main purposes of hope training is to eliminate individuals from false hope syndrome. False hope syndrome particularly occurs when one believes that changing their behavior is easy and the outcomes of the change will be evidenced in a short period of time.
L-RNA aptamers, built using L-ribose, are the enantiomers of natural oligonucleotides, which are made with D-ribose. Nucleic acid aptamers, including L-RNA aptamers, contain adenosine monophosphate, guanosine monophosphate, cytidine monophosphate, uridine monophosphate, a phosphate group, a nucleobase and a ribose sugar.
The Central Command adds it struck roughly 140 military targets in Iran after the attack. CENTCOM declares that the strait is "open to all vessels" and "Iran does not control" it. CENTCOM announces that it conducted additional strikes on dozens of Iranian targets over attacks against vessels to further degrade the regime's capability to attack civilian sailors and commercial ships in the strait. The US forces use suicide drone boats in combat for the first time to strike an Iranian submarine and ship maintenance facility at Bandar Abbas Naval Base. Mitch McConnell releases a statement amidst ongoing speculation about his health, stating he was hospitalized for pneumonia. July 13 2026 Iran war: Trump announces that the US will reinstate the "Iranian blockade in the Strait of Hormuz" and impose a 20% toll on cargo shipping through the strait. According to Trump, "The U.S.A. will be, from this point forward, known as 'THE GUARDIAN OF THE HORMUZ STRAIT.'" Trump describes it as a matter of fairness, claiming that the toll would cover "any and all costs necessary to do the job of providing safety and security to this very volatile section of the world." American-led Combined Maritime Forces' Joint Maritime Information Centre (JMIC) announces that the US naval blockade on Iran will start the following day. Trump formally informs the US Congress that the country has renewed hostilities against Iran. Trump declares that the US will hit Iran hard on that day and the next day, saying that the MoU was a test that the regime did not honor.
Sources: en.wikipedia.org
=== Erroneous and incomplete discoveries === In 1914, Stefan Meyer, Viktor F. Hess, and Friedrich Paneth (working in Vienna) made measurements of alpha radiation from various substances, including 227Ac. They observed the possibility of a minor alpha branch of this nuclide, though follow-up work could not be done due to the outbreak of World War I. Their observations were not precise and sure enough for them to announce the discovery of element 87, though it is likely that they did indeed observe the decay of 227Ac to 223Fr. Soviet chemist Dmitry Dobroserdov was the first scientist to claim to have found eka-caesium, or francium. In 1925, he observed weak radioactivity in a sample of potassium, another alkali metal, and incorrectly concluded that eka-caesium was contaminating the sample (the radioactivity from the sample was from the naturally occurring potassium radioisotope, potassium-40). He then published a thesis on his predictions of the properties of eka-caesium, in which he named the element russium after his home country. Shortly thereafter, Dobroserdov began to focus on his teaching career at the Polytechnic Institute of Odesa, and he did not pursue the element further. The following year, English chemists Gerald J. F. Druce and Frederick H. Loring analyzed X-ray photographs of manganese(II) sulfate. They observed spectral lines which they presumed to be of eka-caesium. They announced their discovery of element 87 and proposed the name alkalinium, as it would be the heaviest alkali metal.
Caitlin Thomas died in 1994 and was buried alongside her husband's grave. Thomas's father, "DJ", died on 16 December 1952 and his mother Florence in August 1958. Thomas's elder son, Llewelyn, died in 2000, his daughter, Aeronwy in 2009, and his younger son, Colm, in 2012.
The puruṣamr̥ga plays a significant role in daily as well as yearly ritual of South Indian Hindu temples. In the Shodhasha-Upakaara (or sixteen honors) ritual, performed between one and six times at significant sacred moments through the day, it decorates one of the lamps of the Deepaaradhana or lamp ceremony. And in several temples the puruṣamr̥ga is also one of the vahana or vehicles of the deity during the processions of the Brahmotsava or festival. In Kanyakumari district, in the southernmost tip of the Indian subcontinent, during the night of Maha Shivaratri, devotees run 75 kilometres while visiting and worshiping at twelve Shiva temples. This Shiva Ottam or Running for Shiva is performed in commemoration of the story of the race between the Purushamirugam and Bhima, one of the Pandavas of the Hindu Epic Mahabharata. The Indian conception of a sphinx that comes closest to the classic Greco-Roman idea is the Sharabha and Gandabherunda, two mythical creatures, part lion, part human, part mammal and part bird, and the form of Sharabha that god Shiva took on and fought with the god Vishnu as Narasimha and Shiva as Sharabha was killed by Vishnu as Gandabherunda in the form of Narashima when Narashima killed Hiranyakashipu. In Sri Lanka and India, the sphinx is known as narasimha or human-lion. As a sphinx, it has the body of a lion and the head of a human being, and is not to be confused with Narasimha, the fourth incarnation of the deity Vishnu; this avatara or incarnation of Vishnu has a human body and the head of a lion and Vishnu as Narashima killed Hiranyakashipu.
==== Denial of cardiovascular health claims ==== In 2001, the U.S. Food and Drug Administration rejected proposed health claims for vitamin E and cardiovascular health. The U.S. National Institutes of Health reviewed literature published up to 2008 and concluded "In general, clinical trials have not provided evidence that routine use of vitamin E supplements prevents cardiovascular disease or reduces its morbidity and mortality." The European Food Safety Authority (EFSA) reviews proposed health claims for the European Union countries. In 2010, the EFSA reviewed and rejected claims that a cause and effect relationship has been established between the dietary intake of vitamin E and maintenance of normal cardiac function or of normal blood circulation.
Sources: en.wikipedia.org
Strontium-90 RTG cores were dumped behind, unlabelled and improperly dismantled, near the Soviet-built Enguri Dam. Three villagers from the nearby village of Lia were unknowingly exposed to it and injured; one of them died in May 2004 from the injuries sustained. The International Atomic Energy Agency led recovery operations and organized medical care. Two remaining RTG cores are yet to be found as of 2022.
Ag+O2− + H2C=CH2 → (CH2CH2)O + AgO The resulting silver oxide then oxidizes ethylene or ethylene oxide to CO2 and water. This reaction replenishes the silver catalyst. Thus the overall reaction is expressed as
Bernice Rubens, novelist Miri Rubin (born 1956), historian and Professor of Medieval and Early Modern History at Queen Mary University of London and author of over ten scholarly academic texts and monographs on religion and the Middle Ages; educated at the Hebrew University of Jerusalem and the University of Cambridge; Rubin writes about social and religious history of Europe between 1100 and 1500, concentrating on interactions between public rituals, power, and community life. Oliver Sacks (9 July 1933 – 30 August 2015), neurologist, naturalist, historian of science, and writer of over twenty books, screenplays and scholarly articles, amongst them, 1973 book Awakenings, which was adapted into an Academy Award-nominated feature film in 1990, starring Robin Williams and Robert De Niro. Nina Salaman, (n15 July 1877 – 22 February 1925) was a British Jewish poet, translator, and social activist. Aside from her original poetry, she is best known for her English translations of medieval Hebrew verse—especially of the poems of Judah Halevi—which she began publishing at the age of 16. Maurice Samuel (1895 – 1972), author of the book You Gentiles, which is controversial for its portrayal of Jews and Gentiles as fundamentally distinct and incompatible civilisations. Samuel's depiction of enduring cultural and psychological differences between the two groups has been described by some critics as implying a form of Jewish supremacy and civilisational separatism.
== History == Aga Khan University Hospital was established in 1985 with a US$300 million investment from Prince Karim Aga Khan. The government of Muhammad Zia-ul-Haq provided an 84-acre site in the heart of Karachi for the University Hospital at no cost.
Two of the main functions of carbohydrates are energy storage and providing structure. The term 'sugar' typically refers to mono- and disaccharides (defined below), which fall into the former category and taste sweet. There are more carbohydrates on Earth than any other known type of biomolecule; they are used to store energy and genetic information, as well as play important roles in cell to cell interactions and communications. Carbohydrates generally have ratios of carbon:hydrogen:oxygen of 1:2:1, meaning a 1:1 ratio of carbon atoms to water (H2O), from which the term "carbohydrate" derives. The simplest type of carbohydrate is a monosaccharide, which have the chemical formula C6H12O6 but vary in their precise structures. Glucose, fructose, and galactose are hexoses, i.e. 6-carbon sugar, sharing the formula C6H12O6, but varying in precise structure. A well-known pentose, or 5-carbon sugar, is deoxyribose (C5H10O4), a component of DNA. A monosaccharide can switch between acyclic (open-chain) form and cyclic form. This occurs through reaction of one of the hydroxyl groups with the carbonyl group on the end of the linear form, bridging them with an oxygen atom and releasing a water molecule in the process. The cyclic molecule has a hemiacetal or hemiketal group, depending on whether the linear form was an aldose or a ketose, which describe the position of the carbonyl group to begin with. In these cyclic forms, the ring usually has 5 or 6 atoms.
Sources: en.wikipedia.org
Reports describe effects on GABA-A receptor expression, monoamine turnover, and neurotrophic factor levels. These are proposed mechanisms drawn mainly from animal models. No single molecular target has been established.
Intranasal delivery is the route described in most published work. It is used because the peptide is degraded quickly once it reaches circulation. Direct evidence of brain penetration in humans is lacking.
Most trials are small, regionally concentrated, and often lack rigorous blinding or placebo control. Independent replication is limited. Reviews in English generally rate the evidence as preliminary.
The sequence is Thr-Lys-Pro-Arg-Pro-Gly-Pro, commonly written as TKPRPGP. It shares the first four residues with tuftsin and carries three prolines in the chain. The proline-rich tail is the main structural feature that separates it from the parent tetrapeptide.