This is a working overview of tuftsin, written for readers who want more than a one-paragraph summary but less than a textbook.
This page was last updated on 2025-07-26 and is reviewed periodically as new material appears.
Once dissolved, the peptide is markedly less stable than the dry powder. Aqueous solutions are subject to backbone hydrolysis and to microbial growth when they are handled without sterile technique. Buffered solutions near neutral pH are common for short-term laboratory work, while acidic conditions are sometimes used to improve solubility. Analytical laboratories generally prepare working solutions fresh rather than storing them, and a residual water film left in a reopened vial can seed degradation even when the container appears dry.
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.
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.
| 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 |
The compound has a calculated molecular weight near 751.9 daltons and carries a net positive charge at physiological pH because of its arginine residue. It dissolves freely in water and in common aqueous buffers, and typically appears as a white or off-white lyophilized powder. The amide backbone makes the molecule susceptible to peptidases, which limits oral use and favors intranasal or parenteral routes. Nomenclature in the literature varies: the substance is also described by the sequence abbreviation TP-7 and by a Russian trade designation.
Regulatory status differs sharply by region. Selank holds a Russian marketing authorization, where it is supplied mainly as nasal drops, while authorities elsewhere have not approved it for medical use. Material sold internationally is therefore usually labeled as a research chemical rather than a medicine. Peer-reviewed publications come predominantly from Russian laboratories, and sample sizes are generally small. Whether the compound produces comparable effects under independent, well-controlled replication remains an open question that the broader literature has not settled.
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.
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.
In 1992, Volkman et al. reported the first evidence of dinosterol in a laboratory culture of a marine diatom Navicula sp., indicating that diatoms may be a source of dinosterol in marine sediments. Within this diatom, 4-methyl sterols comprised less than 0.7% abundance, whereas these sterols are much more abundant in dinoflagellates. Notably, the stereochemistry of the C-24 alkyl substituent in the sterols of diatoms is 24α, whereas in dinoflagellates it is 24β. If the C-24 alkylated sterols in Navicula (CS-46c) are the epimers of dinosterol and dinostanol, then this may be used to discriminate between dinoflagellate and diatom sources of "dinosterol" in sediments. However, the C-24 substituents in steroidal compounds rapidly isomerize in sediments such that a mixture of C-23 and C-24 isomers is formed. Therefore, once the sediment reaches a certain thermal maturity, the stereochemistry at the C-24 position can no longer be used to distinguish between diatom and dinoflagellate sources of dinosterol.
For services to Cricket. Richard Broyd, OBE. Philanthropist. For services to Heritage and Conservation. James Alexander Bullion. Lately Executive Director, Adult Social Services, Norfolk County Council and lately President, Association of Directors of Adult Social Services. For services to Social Care. Robert Geoffrey Burrow, MBE. For services to Motor Neurone Disease Awareness. William Morris Bush. Senior Adviser, Premier League. For services to Sport. Dr. Denise Marie Chaffer. Lately Director, Safety and Learning, NHS Resolution and lately President of the Royal College of Nursing. For services to Patient Safety. Dr. Jung Chang. Author. For services to Literature and to History. David George Crozier. Lately Head, Strategic Partnerships and Engagement, Queen's University Belfast. For services to the Economy. Mark Cutifani. Lately Chief Executive, Anglo American. For services to Investment in the Global Mining Industry. Huw Charles Davies. Lately Chief Executive, British Association for Supported Employment. For services to Employment for Disabled People. Mark William Davies. Director, Windsor Framework Taskforce, Cabinet Office. For Public Service. Dr. Laura Miranda Dawson (Laura Gilbert). Director, Data Science, Prime Minister's Office. For services to Technology and Analysis. Richard George Deverell. Director, Royal Botanic Gardens, Kew. For services to Botanical Science and Conservation. Professor Philip John Diamond. Director General, Square Kilometre Array Observatory. For services to Global Radio Astronomy. Catherine Jane Uttley Dovey.
=== Structural Biology and Protein Engineering === This program studies biomolecules using protein engineering and molecular biology techniques. Methodologies include X-ray crystallography and cryo-EM. Research includes protein structure determination and mass spectrometry methods.
The rates of azoospermia increased with greater CPA dosage, which was attributed to the additional AR antagonism of higher doses of CPA. Significant spermatogenesis still occurs with 50 mg/day CPA alone, but spermatogenesis is significantly reduced compared to normal. At a dosage of 200 mg/day, CPA has been found to produce azoospermia (sperm count of less than 1 million/mL) in men within 8 to 10 weeks of treatment. However, fertility is generally lost even at a lower dosage of CPA of 100 mg/day because there is complete inhibition of the accessory sex glands and hence an absence of semen production and ejaculate upon orgasm. Ejaculate volume decreases at a dosage of 50 mg/day and decreases to almost zero after 6 weeks of high-dose CPA therapy. The effects of CPA on fertility are completely reversible. This has been demonstrated in clinical studies of male adolescents and adults treated with CPA continuously for 6 to 7 years.
==== World War II ==== By World War II, rations had taken modern organized forms for both the Allies and the Axis. The United States Armed Forces revised their World War I-era ration organization system into an alphabetized system: A-rations of fresh food, B-rations of packaged unprepared food, C-rations of prepared canned food, D-rations of chocolate, and K-rations of three-course meals. The US military also issued the 10-in-1 food parcel, designed to supply ten soldiers. A-rations, designed for troops in garrison, included foods such as fresh meat, vegetables, fruits, coffee, and sugar. B-rations, intended for preparation by cooks in field kitchens, contained essentially the same types of foods as A-rations except canned for better preservation. C-rations, intended for troops in the field lacking access to fresh or packaged unprepared food, contained several variations of food combinations, among them meat and beans (including pork and beans), ham, eggs, and potatoes, and chicken and vegetables. D-rations consisted of chocolate bars designed to give needed calories in case soldiers in the field were isolated from any other food source. K-rations were issued to mobile soldiers such as paratroopers, tank crews, and motorcycle couriers. They contained foods such as canned meat, with some canned meat issued together with eggs, carrot or apple, sugar or malted milk tablets, fruit bars, oatmeal, cheese, biscuits, powdered fruit drinks, salt, and chewing gum.
Sources: en.wikipedia.org
At temperatures above 350 °C (662 °F), cellulose undergoes thermolysis (also called 'pyrolysis'), decomposing into solid char, vapors, aerosols, and gases such as carbon dioxide. Maximum yield of vapors which condense to a liquid called bio-oil is obtained at 500 °C (932 °F). Semi-crystalline cellulose polymers react at pyrolysis temperatures (350–600 °C (662–1,112 °F)) in a few seconds; this transformation has been shown to occur via a solid-to-liquid-to-vapor transition, with the liquid (called intermediate liquid cellulose or molten cellulose) existing for only a fraction of a second. Glycosidic bond cleavage produces short cellulose chains of two-to-seven monomers comprising the melt. Vapor bubbling of intermediate liquid cellulose produces aerosols, which consist of short chain anhydro-oligomers derived from the melt. Continuing decomposition of molten cellulose produces volatile compounds including levoglucosan, furans, pyrans, light oxygenates, and gases via primary reactions. Within thick cellulose samples, volatile compounds such as levoglucosan undergo 'secondary reactions' to volatile products including pyrans and light oxygenates such as glycolaldehyde.
First, fluoride can increase the rates of reactions of organotriflates, possibly by the same effect as lithium chloride. Furthermore, fluoride ions can act as scavengers for tin byproducts, making them easier to remove via filtration.
For each diprotic acid titration curve, from left to right, there are two midpoints, two equivalence points, and two buffer regions. Due to the successive dissociation processes, there are two equivalence points in the titration curve of a diprotic acid. The first equivalence point occurs when all first protons from the first ionization are titrated. In other words, the amount of OH− added equals the original amount of H2A at the first equivalence point. The second equivalence point occurs when all protons are titrated. Therefore, the amount of OH− added equals twice the amount of H2A at this time. For a weak diprotic acid titrated by a strong base, the second equivalence point must occur at pH above 7 due to the hydrolysis of the resulted salts in the solution. At either equivalence point, adding a drop of base will cause the steepest rise of the pH value in the system.
Nickel-60 is the daughter product of the extinct radionuclide 60Fe (half-life 2.62 My). Because 60Fe has such a long half-life, its persistence in materials in the Solar System at high enough concentrations may have generated observable variations in the isotopic composition of 60Ni. Therefore, the abundance of 60Ni in extraterrestrial material may provide insight into the origin of the Solar System and its early history/very early history. Unfortunately, nickel isotopes appear to have been heterogeneously distributed in the early Solar System. Therefore, so far, no actual age information has been attained from 60Ni excesses. 60Ni is also the stable end-product of the decay of 60Zn, the last rung of the alpha ladder.
Sources: en.wikipedia.org
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.
=== Machine guns === Vickers machine gun – Not declared obsolete until 1968. Bren light machine gun – Original .303 versions used in early stages of the Cold War, L4A1-A6 7.62mm NATO variants in service from 1955 onwards. M1919 Browning machine gun - Mounted on vehicles and ground tripods L7A1/A2 GPMG - Adopted in 1958. Primary infantry machine gun until the 1980s, when it was replaced in infantry sections by the L86A1 listed below (though it remained in use with support company machine gun platoons). Also mounted on various vehicles. L86A1 Light Support Weapon - Initial batches issued in 1985; frontline Army units, Royal Marines, and RAF Regiment scheduled to be fully equipped by 1987, rest of regular Army scheduled to be fully equipped by 1990.
One important use of American kestrels is in falconry. It is often considered a beginner's bird, though the careful weight control needed to maintain the kestrel's desire to aggressively hunt takes skill. Falconers experienced in extracting the best performance the species is capable of, report they are highly reliable on the normal game of sparrows and starlings. More aggressive individuals are sometimes capable of capturing prey up to approximately twice their own body weight, allowing the occasional capture of true game birds such as quail and dove. However, most falconers interested in the reliable taking of such game do prefer larger falcons or hawks. The advantage the American kestrel offers the experienced falconer is its suitability to simple and urban falconry not requiring large tracts of land or the use of hunting dogs. This form of falconry is sometimes referred to as "micro-falconry" or "micro-hawking". The other small raptor species commonly used in micro-falconry are the merlin, the sharp-shinned hawk (the smallest Accipiter), and the European kestrel (a true kestrel). Hawking with the American kestrel requires adapting to the strengths and weaknesses of the bird. It is a tiny falcon, and even for its size, it is less muscular than other small falcons such as the athletic and swift merlin. It is more adapted to ambush hunting and short chases than to the longer aerial chases larger falcons often adopt. Used within its limits, it is effective.
== Developments == Due to the shortage of plutonium-238, a new kind of RTG assisted by subcritical reactions has been proposed. In this kind of RTG, the alpha decay from the radioisotope is also used in alpha-neutron reactions with a suitable element such as beryllium. This way a long-lived neutron source is produced. Because the system has a criticality close to but less than 1, i.e. Keff < 1, a subcritical multiplication is achieved which increases the neutron background and produces energy from fission reactions. Though the number of fissions produced in the RTG is very small (making their gamma radiation negligible), because each fission releases over 30 times more energy than each alpha decay (200 MeV compared to 6 MeV), up to a 10% energy gain is attainable, which translates into a reduction of the 238Pu needed per mission. The idea was proposed to NASA in 2012 for the yearly NASA NSPIRE competition, which translated to Idaho National Laboratory at the Center for Space Nuclear Research (CSNR) in 2013 for studies of feasibility. However the essentials are unmodified. RTG have been proposed for use on realistic interstellar precursor missions and interstellar probes.An example of this is the Innovative Interstellar Explorer (2003–current) proposal from NASA.An RTG using 241Am was proposed for this type of mission in 2002.This could support mission extensions up to 1000 years on the interstellar probe, because 241Am decays more slowly than 238Pu.Other isotopes for RTG were also examined in the study, looking at traits such as watt/gram, half-life, and decay products.
=== Production of ethylene glycol === Ethylene glycol is industrially produced by non-catalytic hydration of ethylene oxide at a temperature of 200 °C (392 °F) and a pressure of 1.5–2 MPa (220–290 psi):
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 peptide made of seven amino acids. It is modeled on tuftsin, a natural tetrapeptide, with an added three-residue tail. It is not a small-molecule drug.