Everything below concerns lyophilization. We keep the language plain, cite what the science says, and separate well-supported claims from open questions.
Last reviewed on 2026-04-20. Where a claim depends on a specific study, the study is described rather than over-claimed.
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.
Reported pharmacological effects center on reduced anxiety-like behavior in animal models and on measures of memory and learning. Proposed contributing mechanisms include modulation of GABAergic signaling, shifts in monoamine turnover, and changes in the activity of enzymes that degrade neuropeptides. Effects on the expression of genes linked to neuroplasticity have also been described. No single molecular target is widely accepted, and whether the behavioral findings arise from one pathway or several remains an open question.
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.
| Property | Value | Notes |
|---|---|---|
| Typical purity specification | 95 percent or higher by RP-HPLC | Area percentage of the main peak |
| Identity confirmation | Electrospray ionization mass spectrometry | Observed mass compared with the theoretical value near 751.9 Da |
| Recommended dry storage | -20 °C, desiccated | -80 °C for multi-year archival material |
| Solution handling | Prepare fresh; avoid long storage | Sterile filtration reduces microbial load |
| Common synonyms | TKPRPGP; TP-7 | Sequence code and laboratory designation used interchangeably |
Published clinical work is concentrated in Russian-language journals and generally involves small samples without independent replication. Systematic reviews in English note the shortage of randomised, placebo-controlled trials and the difficulty of verifying methods from translated reports. Outcome measures vary between studies, which complicates pooling of results. Interest in the compound as a cognitive or anxiolytic agent therefore rests on a thinner evidence base than the volume of citations suggests. Replication in well-powered trials with preregistered endpoints would be needed before firm conclusions about efficacy can be drawn.
Proposed mechanisms centre on the GABAergic system. Animal and tissue studies report changes in GABA-A receptor expression and reduced activity of GABA transaminase, the enzyme that degrades GABA. Effects on monoamine turnover, including serotonin and dopamine pathways, are also described, and a separate line of work links the peptide to increased expression of brain-derived neurotrophic factor in hippocampal tissue. Most of these findings come from rodent models and cell preparations. How the individual observations combine into a single coherent mode of action is not settled.
Pharmacokinetic data are sparse and largely derived from animal work. After intranasal administration the peptide appears in plasma within minutes, and reported half-lives are short, on the order of minutes to tens of minutes. Degradation proceeds through ordinary proteolytic cleavage into constituent amino acids and smaller fragments. Direct evidence that intact Selank reaches brain tissue in meaningful amounts is limited, and the extent of blood-brain barrier penetration is debated. Some authors argue that fragments, not the parent peptide, carry much of the observed activity.
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.
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.
Identity and purity are usually assessed by reversed-phase high-performance liquid chromatography, with mass spectrometry used to confirm molecular mass and sequence information. Amino acid analysis and peptide mapping may supplement these methods. Certified reference standards are scarce, and many commercial lots are sold as research chemicals without a pharmacopoeial monograph. Regulatory treatment differs by country: Selank is a registered prescription medicine in Russia, while in the European Union and the United States it is not an approved drug and may fall under research-chemical or unapproved-product frameworks.
Selank is a hydrophilic peptide and dissolves readily in water and in aqueous buffers. The lyophilised powder is typically a white to off-white solid. Because short peptides are prone to hydrolysis and oxidation, handling benefits from limiting exposure to heat, moisture and strong light. Working solutions are commonly prepared in sterile water or saline, and repeated freeze-thaw cycles are avoided to reduce aggregation and loss of activity. These practices reflect general laboratory convention rather than published stability specifications.
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.
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.
== Clinical implications == Disposition index is used as a measure of beta cell function and the ability of the body to dispose of a glucose load. Thus a lowering of disposition index predicts the conversion of insulin resistance to diabetes mellitus type 2. Disposition index, but not insulin resistance, can predict type 2 diabetes in persons with normal blood glucose levels, but who do not have a family history (genetic predisposition) to type 2 diabetes. Disposition index can be increased by aerobic exercise, but only to the extent that insulin sensitivity is improved. The static disposition index (SPINA-DI) declines with increasing adherence to mediterranean diet. This may result from increased use of other macronutrients for the provision of energy and a reduction in the chronic stimulus for dynamical compensation with consecutive insulin hypersecretion. The disposition index is reduced in several chronic conditions including cystic fibrosis, reduced PCSK9 expression and inflammatory diseases, e.g. hidradenitis suppurativa (acne inversa).
=== Discontinued === AS-601811 – oral – male pattern baldness – 5α-reductase inhibitor ATI-501 (A-201; ATI-50001) – oral – alopecia areata – Janus kinase 1 inhibitor, Janus kinase 3 inhibitor Brepocitinib (PF-06700841) – oral – alopecia, alopecia areata – Janus kinase 1 inhibitor, TYK2 kinase inhibitor Cioteronel (CPC-10997; Cyoctol, X-Andron) – topical – alopecia – androgen receptor antagonist Diazoxide – topical – alopecia – potassium channel opener Denileukin diftitox (Lymphirtm, Ontak, Remitoro; LY-335348; DAB389 interleukin-2) – unknown – alopecia – protein synthesis inhibitor Epristeride (Aipuliete; ONO-9302, SKF-105657) – oral – alopecia – 5α-reductase inhibitor Etrasimod (Verespiti, Velspity; APD-334, PF-07915503) – oral – alopecia areata – sphingosine 1 phosphate receptor modulator Farudodstat (ASLAN-003, LAS-186323) – oral – alopecia areata – dihydroorotate dehydrogenase inhibitor HST-001 (HSC-660) – intradermal – alopecia – intercellular signalling peptide and protein replacement Ifidancitinib (A-301, ATI-50002, ATI-502) – topical – alopecia, alopecia areata – Janus kinase 1 inhibitor, Janus kinase 3 inhibitor MK-434 (MK-0434) – oral – alopecia – 5α-reductase inhibitor Naminidil (BMS-234303) – topical – alopecia – potassium channel opener NEOSH–101 – topical – alopecia – undefined mechanism of action P-1075 – unknown – alopecia – potassium channel opener Piliel – topical – alopecia – undefined mechanism of action Research programme: androgen receptor antagonists - Endoceutics (EM-4350, EM-6537) – unknown – male pattern baldness – androgen receptor antagonists Research programme: oligonucleotide therapeutics for alopecia - OliPass – unknown – alopecia – androgen receptor antagonists RU-58841 (PSK-3841, HMR-3841) – topical – alopecia – androgen receptor antagonist Secukinumab (Cosentyx) – injection – alopecia areata – IL17A protein inhibitor Setipiprant (ACT-129968, KYTH-105) – oral – alopecia – prostaglandin D2 receptor antagonist Timbetasin (thymosin β4) – unknown – alopecia – various mechanisms of action Tralokinumab (Adbry, Adtralza; CAT-354, LP-0162) – subcutaneous injection – alopecia areata – interleukin-13 inhibitor TU-2100 – topical – hair disorders – undefined mechanism of action Viprostol (CL-115347) – topical – alopecia – synthetic prostaglandin E2 analogue
The Inter-American Commission on Human Rights called "upon the United States to: refrain from employing lethal military force in the context of public security operations, ensuring that any counter-crime or security operation fully complies with international human rights standards; conduct prompt, impartial, and independent investigations into all deaths and detentions resulting from these actions; and adopt effective measures to prevent recurrence" and urged the US to "to ensure that all security operations, including those carried out beyond its borders, are consistent with international human rights obligations, particularly regarding the protection of the right to life, the use of force, due process guarantees, and accountability mechanisms."
One potential scenario that has been envisioned is out-of-control self-replicating molecular assemblers in the form of gray goo which consumes carbon to continue its replication. If unchecked, such mechanical replication could potentially consume whole ecoregions or the whole Earth (ecophagy), or it could simply outcompete natural lifeforms for necessary resources such as carbon, ATP, or UV light (which some nanomotor examples run on). However, the ecophagy and 'grey goo' scenarios, like synthetic molecular assemblers, are based upon still-hypothetical technologies that have not yet been demonstrated experimentally.
=== 2011–2017: The Only Way Is Essex, I'm a Celebrity...Get Me Out of Here! and Celebrity Big Brother === In January 2011, Julie Childs, mother of Collins' friend Amy, suggested to producers of the ITV2 reality series The Only Way Is Essex that Collins would be an appropriate subject. They visited Collins' house and subsequently filmed her and her friends for two weeks. After returning to work as a car sales executive for a week, she was cast in the programme and began appearing in The Only Way Is Essex from its second series beginning in March 2011. Her first scene saw her attempting to sell a car to Kirk Norcross and taking him for a test drive. Collins ultimately quit her job to appear on the programme full time, and was paid £50 a day for her early appearances on the show, which she described as a "massive risk". Her mother Joan joined the programme during the fifth series in April 2012. From September 2011 until March 2013, Collins wrote a regular column in the tabloid magazine Closer. In April 2013, she released her debut autobiography Basically...: My Life as a Real Essex Girl, which became a bestseller in its first week of release. In January 2014, Collins took part in the second series of the ITV diving competition Splash!. During training, Collins suffered severe bruising and admitted she had to overcome a fear of water. She became the third celebrity to be eliminated after losing the splash-off to Michaela Strachan in the first heat. In November 2014, she took part in the fourteenth series of I'm a Celebrity...Get Me Out of Here! on ITV.
Sources: en.wikipedia.org
These are made especially problematic due to the chemical solvents' ability to extract far greater amounts of the potentially toxic compounds than water. In the context of these concerns, the World Health Organization advises against the consumption of ethanolic and acetonic kavalactone extracts, and says that "products should be developed from water-based suspensions of kava". The government of Australia prohibits the sales of such kavalactone extracts, and only permits the sale of kava products in their natural form or produced with cold water.
Biden did not support national same-sex marriage rights while in the Senate and voted for the Defense of Marriage Act, but opposed proposals for constitutional amendments that would have banned same-sex marriage nationwide. Biden has supported same-sex marriage since 2012. As a senator, Biden forged deep relationships with police groups and was a chief proponent of a Law Enforcement Officers' Bill of Rights measure that police unions supported but police chiefs opposed. In 2020, Biden also ran on decriminalizing cannabis, after advocating harsher penalties for drug use as a senator. Biden believes action must be taken on climate change. As a senator, he co-sponsored the Boxer–Sanders Global Warming Pollution Reduction Act, the most stringent climate bill in the United States Senate. Biden supports nature conservation. According to a report from the Center for American Progress, he broke several records in this domain. He took steps to protect old-growth forests. Biden opposes drilling for oil in the Arctic National Wildlife Refuge. He wants to achieve a carbon-free power sector in the U.S. by 2035 and stop emissions completely by 2050. His program included reentering the Paris Agreement, green building and more. Biden supports environmental justice, including climate justice and ocean justice. Biden called global temperature rise above the 1.5°C limit the "only existential threat humanity faces even more frightening than a nuclear war".
The structure of hemoglobins varies across species. Hemoglobin occurs in all kingdoms of organisms, but not in all organisms. Primitive species such as bacteria, protozoa, algae, and plants often have single-globin hemoglobins. Many nematode worms, molluscs, and crustaceans contain very large multisubunit molecules, much larger than those in vertebrates. In particular, chimeric hemoglobins found in fungi and giant annelids may contain both globin and other types of proteins. One of the most striking occurrences and uses of hemoglobin in organisms is in the giant tube worm (Riftia pachyptila, also called Vestimentifera), which can reach 2.4 meters length and populates ocean volcanic vents. Instead of a digestive tract, these worms contain a population of bacteria constituting half the organism's weight. The bacteria oxidize H2S from the vent with O2 from the water to produce energy to make food from H2O and CO2. The worms' upper end is a deep-red fan-like structure ("plume"), which extends into the water and absorbs H2S and O2 for the bacteria, and CO2 for use as synthetic raw material similar to photosynthetic plants. The structures are bright red due to their content of several extraordinarily complex hemoglobins that have up to 144 globin chains, each including associated heme structures. These hemoglobins are remarkable for being able to carry oxygen in the presence of sulfide, and even to carry sulfide, without being completely "poisoned" or inhibited by it as hemoglobins in most other species are.
Biomass is a form of renewable energy useful as fuel and as a source of some chemical products. Relative to coal and petroleum however, the energy content of biomass is low. Compared to traditional fossil fuels, biomass has a high oxygen content. Its carbon is partially combusted, so to speak. One such notable example is the production of bio-ethanol. There is a general classification of biomass that is produced or sourced for conversion processes. Biofuels such as bioethanol and biodiesel, and bioplastics, are typically derived from primary or “first-generation” source energy-dense plants and oils such as rapeseed, sugarcane, or corn. Their high content of sugars and oils makes them ideal as feedstocks, however, there are drawbacks to their use. As well as inflating the price of the chosen crop due to increased demand, arable land that would otherwise be used to grow food for human and animal consumption is rendered unavailable. Secondary or “second-generation” source biomass encompasses a much wider variety of plant and animal matter. It may be derived from a relatively pure source, such as wood chippings or grass, or it may be a less well defined solid waste stream. This type of biomass is far more challenging to work with, as it contains a more varied mixture of compounds that cannot be easily converted into useful products.
== Pathogenesis == The mechanisms underlying brain catatonia are poorly understood. Currently, there are two main categories of explanations for the brain pathology of catatonia. The first is a disruption of normal neurotransmitter production or release in certain brain areas, preventing normal cognitive function and leading to behavioral and motor symptoms associated with catatonia. The second claims that disruption of communication between different areas of the brain causes catatonia.
Sources: en.wikipedia.org
== Early life == On March 21, 1906, John Davison Rockefeller III was born in New York City, New York. His parents were John Davison Rockefeller Jr. (1874–1960) and Abigail Greene "Abby" Aldrich (1874–1948), philanthropists. He had four younger brothers, Nelson, Winthrop, Laurance and David, and an elder sister, Abby. Through his father, he was a grandson of Standard Oil co-founder John Davison Rockefeller Sr. and schoolteacher Laura Celestia "Cettie" Spelman. Through his mother, he was a grandson of Senator Nelson Wilmarth Aldrich and Abigail Pearce Truman "Abby" Chapman. He received his preparatory education at the Browning School in New York City and the Loomis Chaffee School, Windsor, Connecticut, in 1925. He went to Princeton University where he received high honors in economics and graduated in 1929 with the degree of Bachelor of Science, choosing industrial relations as the subject of his senior thesis. His interest in industrial relations stemmed from the family's role in the Ludlow Massacre, in which strikebreakers and security guards killed women and children of miners striking against the Rockefeller-controlled Colorado Fuel and Iron Company. Rockefeller's father worked to restore the family's public reputation by championing industrial relations and the work of William Lyon Mackenzie King, a pioneer in the field. Commencing a lifelong commitment to international relations, he undertook a world tour after graduating from college, which concluded with assignments for the Institute of Pacific Relations conference in Japan.
== External links == Rudra MN, Chowdhury LM (30 September 1950). "Methionine Content of Cereals and Legumes". Nature. 166 (568): 568. Bibcode:1950Natur.166..568R. doi:10.1038/166568a0. PMID 14780151. S2CID 3026278.
Early in 1953 Watson and Crick proposed a correct structure for the DNA double helix. Pauling later cited several reasons to explain how he had been misled about the structure of DNA, among them misleading density data and the lack of high quality X-ray diffraction photographs. Pauling described this situation as "the biggest disappointment in his life". During the time Pauling was researching the problem, Rosalind Franklin in England was creating the world's best images. They were key to Watson's and Crick's success. Pauling did not see them before devising his mistaken DNA structure, although his assistant Robert Corey did see at least some of them, while taking Pauling's place at a summer 1952 protein conference in England. Pauling had been prevented from attending because his passport was withheld by the State Department on suspicion that he had Communist sympathies. This led to the legend that Pauling missed the structure of DNA because of the politics of the day (this was at the start of the McCarthy period in the United States). Politics did not play a critical role. Not only did Corey see the images at the time, but Pauling himself regained his passport within a few weeks and toured English laboratories well before writing his DNA paper. He had ample opportunity to visit Franklin's lab and see her work, but chose not to. Despite these times, Pauling chose to move on from them and be thankful for the discoveries that he had already found.
=== Transition and swearing-in ceremony === Melo named Porto Alegre councilman and former mayor of Santa Maria, Cezar Schirmer, as his transition coordinator for the transition between the Marchezan government and his. In his inaugural speech on 1 January 2021, Melo affirmed that was necessary to "raise the optimism" for the city, as the city, due to the COVID-19 pandemic, had been going through rough times economically and socially.
Sources: en.wikipedia.org
Sealed, desiccated storage at -20 °C or colder is the standard recommendation for research-grade material. Vials should reach room temperature before they are opened, which limits condensation. Repeated temperature cycling is discouraged.
A reported purity value reflects the share of the main peak in one chromatographic run and says nothing about identity. Confirming that the expected sequence is present requires a separate measurement such as mass spectrometry. Purity and identity are distinct questions.
A mass spectrum reports the molecular masses present in a sample and shows whether they match the value expected for selank, near 751.9 Da. It also flags common artifacts such as truncation or adduct formation. It does not establish correct stereochemistry or complete sequence order on its own.
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.