This is a working overview of heptapeptide, written for readers who want more than a one-paragraph summary but less than a textbook.
Reviewed 2025-08-30. Anything still debated is marked as such rather than presented as settled.
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.
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.
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.
| 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 |
Handling follows standard practice for research peptides. Material is weighed in a low-humidity environment because the powder absorbs atmospheric moisture. Purity is reported as the percentage area of the main peak in a chromatogram, with specifications commonly set at 95 percent or higher; values below that threshold indicate the presence of truncated or modified species. Residual trifluoroacetate from purification is often present and may affect mass balance. Certificates of analysis should state the analytical method, the column and gradient used, and the lot-specific retention time so that results can be compared across suppliers.
Identity and purity of selank are established with reversed-phase high-performance liquid chromatography coupled to mass spectrometry. The peptide elutes from C18 columns with acetonitrile gradients in water containing trifluoroacetic acid or formic acid, and detection is usually performed by ultraviolet absorbance near 214 nm. Electrospray ionization in positive mode gives a doubly protonated ion near m/z 377, consistent with a mass of about 752 Da. Amino acid analysis or tandem mass spectrometry of fragment ions confirms the sequence. Because the molecule has no aromatic residues, it lacks a usable 280 nm chromophore, so low-wavelength detection or mass spectrometry is required.
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.
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.
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.
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.
==== Umeko ==== Koume Kodou (胡堂 小梅, Kodō Koume), also known as "Umeko" (ウメコ), is a ditzy, yet kind-hearted and perky, member of the team who serves as Deka Pink (デカピンク, Deka Pinku), though she frequently claims to be the field leader. Throughout the series, she spends every moment she can in a bubble bath with her three rubber ducks, Umeyo, Umenosuke, and Umegoro. After learning of Sen-chan's feelings for her, she moves in with him, as of the crossover film Mahō Sentai Magiranger vs. Dekaranger. As Deka Pink, Umeko wields the D-Knuckle and D-Stick, which can combine to form the D-Shot and allow her to perform the Twin Cam Shot alongside Jasmine. Using the SP License's Masquerade Mode (マスカレイドモード, Masukareido Mōdo), she can instantaneously change her outfit for disguise purposes. Umeko is portrayed by Mika Kikuchi (菊地 美香, Kikuchi Mika).
==== Blood stains ==== There are several reddish stains on the shroud suggesting blood. McCrone (see painting hypothesis) showed that these contain iron oxide, and theorized that its presence was likely due to simple pigment materials used in medieval times. While the forensic doctor Pierluigi Baima Bollone initially claimed in 1983 to have identified type AB human blood along with traces of serum, aloes, and myrrh, this conclusion was later challenged by researchers like Alan Adler and more recently Kelly Kearse, who noted that early testing methods could not definitively confirm ancient human blood due to degradation and potential contamination. Skeptics cite forensic blood tests whose results dispute the authenticity of the Shroud, and point to the possibility that the blood could belong to a person who handled the shroud, and that the apparent blood flows on the shroud are unrealistically neat. As of 2025, it has not been scientifically demonstrated that the blood is of human, or even primate, origin.
Ginkgo has long been cultivated in China. It is common in the southern third of the country. Some planted trees at temples are believed to be over 1,500 years old. The first record of Europeans encountering it is in 1690 in Japanese temple gardens, where the tree was seen by the German botanist Engelbert Kaempfer. Because of its status in Buddhism and Confucianism, the ginkgo has also been widely planted in Korea and in Japan since the 14th century; in both areas, some naturalization has occurred, with ginkgos seeding into natural forests. Ginkgo has been commonly cultivated in North America for over 200 years and in Europe for close to 300, but during that time, it has never become significantly naturalized. G. biloba is also commonly manually planted in cities across the United States and Europe. This species is highly tolerant to pollution and serves as a visually appealing, shade-providing tree in many cities and gardens. Many intentionally planted ginkgos are male cultivars grafted onto plants propagated from seed, because the male trees will not produce the malodorous seeds. The popular cultivar 'Autumn Gold' is a clone of a male plant. The disadvantage of male Ginkgo biloba trees is that their pollen is highly allergenic. They have an OPALS (Ogren Plant Allergy Scale) rating of 7 (out of 10), whereas female trees, which can produce no pollen, have an OPALS allergy scale rating of 2.
== Anopheles gambiae in the strict sense == An. gambiae sensu stricto (s.s.) has been discovered to be currently in a state of diverging into two different species—the Mopti (M) and Savannah (S) strains—though as of 2007, the two strains are still considered to be a single species. A mechanism of species recognition using the sound emitted by the wings and identified by Johnston's organ was proposed in 2010, however this mechanism has never been confirmed since, and the overall mechanism theory through "harmonic convergence" has been challenged.
=== Overview === Undeterred by opposition, the Meiji leaders continued to modernize the nation through government-sponsored telegraph cable links to all major Japanese cities and the Asian mainland and construction of railroads, shipyards, munitions factories, mines, textile manufacturing facilities, factories, and experimental agriculture stations. Greatly concerned about national security, the leaders made significant efforts at military modernization, which included establishing a small standing army, a large reserve system, and compulsory militia service for all men. Foreign military systems were studied, foreign advisers, especially French ones, were brought in, and Japanese cadets sent abroad to Europe and the United States to attend military and naval schools.
Sources: en.wikipedia.org
Gold nanoparticles show potential as intracellular delivery vehicles for antisense oligonucleotides (single and double stranded DNA) by providing protection against intracellular nucleases and ease of functionalization for selective targeting.
On 26 September 1937, the acting British district commissioner of Galilee, Lewis Yelland Andrews, was assassinated in Nazareth. Four days later Britain outlawed the Arab Higher Committee, and began to arrest its members. On 1 October 1937, the National Bloc, the Reform Party and the Istiqlal Party were dissolved. Yaqub al-Ghusayn, Al-Khalidi and Ahmed Hilmi Pasha were arrested and then deported. Jamal al-Husayni escaped to Syria, as did Abd al-Qadir al-Husayni. Amin al-Husayni managed to escape arrest, but was removed from the presidency of the Supreme Muslim Council. The committee was banned by the Mandate administration and three members (and two other Palestinian leaders) were deported to the Seychelles and the others moved into voluntary exile in neighbouring countries. Awni Abd al-Hadi, who was out of the country at the time, was not allowed to return. The National Defence Party, which had withdrawn from the AHC soon after its formation, was not outlawed, and Raghib al-Nashashibi was not pursued by the British.
==== Premenstrual syndrome ==== Historically, progesterone has been widely used in the treatment of premenstrual syndrome. A 2012 Cochrane review found insufficient evidence for or against the effectiveness of progesterone for this indication. Another review of 10 studies found that progesterone was not effective for this condition, although it stated that insufficient evidence is available currently to make a definitive statement on progesterone in premenstrual syndrome.
== Early life and research == Atul Malhotra is a US citizen born in Edmonton, Alberta, Canada. He attended the University of Alberta in Canada, obtaining a bachelor's degree in Chemistry and a Medical degree in chemistry from the same university. He completed his internal medicine residency at the Mayo Clinic in Rochester, Minnesota. Malhotra does research in the domains of pulmonary medicine, intensive care unit (ICU), obstructive sleep apnea (OSA), and other respiratory biology disciplines. He studies the biology underlying the consequences of sleep apnea as well as its causation. His group uses computational modelling, cell culture techniques, rodent models, epidemiology, and clinical trials in addition to its primary focus on human physiology. Finding new therapeutic targets for sleep apnea is the main goal of his lab to meet a critical public health need. He was global principal investigator for the SURMOUNT-OSA study which led to the FDA approval of tirzepatide for treatment of moderate to severe sleep apnea in people with obesity.
The revisionist interpretation produced a critical reaction of its own. In a variety of ways, "post-revisionist" scholarship before the fall of Communism challenged earlier works on the origins and course of the Cold War. During the period, "post-revisionism" challenged the "revisionists" by accepting some of their findings, but rejecting most of their key claims. Another current attempt to strike a balance between the "orthodox" and "revisionist" camps, identifying areas of responsibility for the origins of the conflict on both sides. For example, Thomas G. Paterson in Soviet-American Confrontation (1973) viewed Soviet hostility and United States efforts to dominate the postwar world as equally responsible for the Cold War. The seminal work of this approach was John Lewis Gaddis's The United States and the Origins of the Cold War, 1941–1947 (1972). The account was immediately hailed as the beginning of a new school of thought on the Cold War claiming to synthesize a variety of interpretations. Gaddis then maintained that "neither side can bear sole responsibility for the onset of the Cold War". However, he emphasized the constraints imposed on United States policymakers by the complications of domestic politics. In addition, Gaddis has criticized some revisionist scholars, particularly Williams, for failing to understand the role of Soviet policy in the origins of the Cold War. Gaddis's 1983 distillation of post-revisionist scholarship became a major channel for guiding subsequent Cold War research.
Sources: en.wikipedia.org
=== Biosynthesis === Ricin is synthesized in the endosperm of castor oil plant seeds. The ricin precursor protein is 576 amino acid residues in length and contains a signal peptide (residues 1–35), the ricin A chain (36–302), a linker peptide (303–314), and the ricin B chain (315–576). The N-terminal signal sequence delivers the prepropolypeptide to the endoplasmic reticulum (ER) and then the signal peptide is cleaved off. Within the lumen of the ER the propolypeptide is glycosylated and a protein disulfide isomerase catalyzes disulfide bond formation between cysteines 294 and 318. The propolypeptide is further glycosylated within the Golgi apparatus and transported to protein storage bodies. The propolypeptide is cleaved within protein bodies by an endopeptidase to produce the mature ricin protein that is composed of a 267 residue A chain and a 262 residue B chain that are covalently linked by a single disulfide bond.
=== Medical specialty === The beginning of psychiatry as a medical specialty is dated to the middle of the nineteenth century, although its germination can be traced to the late eighteenth century. In the late 17th century, privately run asylums for the insane began to proliferate and expand in size. In 1713, the Bethel Hospital Norwich was opened, the first purpose-built asylum in England. In 1656, Louis XIV of France created a public system of hospitals for those with mental disorders, but as in England, no real treatment was applied. During the Enlightenment, attitudes towards the mentally ill began to change. It came to be viewed as a disorder that required compassionate treatment. In 1758, English physician William Battie wrote his Treatise on Madness on the management of mental disorder. It was a critique aimed particularly at the Bethlem Royal Hospital, where a conservative regime continued to use barbaric custodial treatment. Battie argued for a tailored management of patients entailing cleanliness, good food, fresh air, and distraction from friends and family. He argued that mental disorder originated from dysfunction of the material brain and body rather than the internal workings of the mind.
Drew won an athletics scholarship to Amherst College in Massachusetts, where he played on the football as well as the track and field teams, and graduated in 1926. After college, Drew spent two years (1926–1928) as a professor of chemistry and biology, the first athletic director, and a football coach at the historically black private Morgan College in Baltimore, Maryland, to earn the money to pay for medical school. For his medical career Drew applied to Howard University, Harvard Medical School, and later McGill University. Drew lacked some prerequisites for Howard University, and Harvard wanted to defer him a year, so to begin medical school promptly, Drew decided to attend McGill's medical school in Montreal, Canada. It was during this stage in his medical journey that Drew worked with John Beattie, who was conducting research regarding the potential correlations between blood transfusions and shock therapy. Shock occurs as the amount of blood in the body rapidly declines which can be due to a variety of factors such as a wound or dehydration. As the body goes into shock, both blood pressure and body temperature decrease which then causes a lack of blood flow and a loss of oxygen in the body's tissues and cells. Eventually, it became clear that transfusions were the solution to treating victims of shock, but at the time there was no successful method of transportation or mass storage of blood, leaving transfusions to be extremely limited to location.
== Confession, arrest, and conviction == Wettlaufer entered an inpatient drug rehabilitation program at the Centre for Addiction and Mental Health (CAMH) in Toronto, on September 16, 2016. There, she confessed to CAMH staff about killing or attempting to kill her patients, leading to CAMH notifying the College of Nurses of Ontario (CNO) and the Toronto Police Service. She then emailed CNO to resign as a registered nurse because she had "deliberately harmed patients in [her] care and [was] now being investigated by the police for same", personally called an investigator from CNO, and had CAMH staff fax a four-page handwritten confession. Wettlaufer had confessed to killing patients several times prior to her confession at CAMH, including to a lawyer who advised her to keep it a secret, and was not reported to police. After providing police with a two-hour-long confession, she was formally charged with the eight murders on October 25. After further investigation, she was also charged with four counts of attempted murder and two counts of aggravated assault on January 13, 2017. Wettlaufer waived her right to a preliminary hearing and confessed to all charges in court on June 1. On June 26, she was sentenced to eight concurrent life terms in prison, with no possibility of parole for 25 years. In her confession, Wettlaufer admitted that she "knew the difference between right and wrong" but she was visited by "surges" she could not control. She said, "God or the devil or whatever, wanted me to do it." After one murder, she felt "the surging ...
Third, Article 101 of the TFEU prohibits cartels or collusive practices, including competitors engaging in (a) price fixing, (b) limiting production, (c) sharing markets, (d) applying dissimilar conditions to equivalent transactions, and (e) making contracts subject to unconnected obligations. According to Article 101(2) any such agreements between undertakings are automatically void. Article 101(3) establishes exemptions, if the collusion is for distributional or technological innovation, gives consumers a "fair share" of the benefit and does not include unreasonable restraints that risk eliminating competition anywhere. For example, in Parker ITR Srl v Commission eleven corporations that manufactured marine hoses for offshore oil rigs were fined €131 million for rigging bids and sharing markets worldwide – they would designate a "bid champion" in each case to raise prices. Secret cartels are often hard to prove, so the courts allow competition regulators to establish collusion where there is no other plausible explanation for price rises. Some agreements among businesses, however, can be highly beneficial. For instance, in a decision on the Conseil Européen de la Construction d'Appareils Domestiques, the Commission held an agreement among washing machine makers to phase out production of low-efficiency machines was lawful, especially since it would lead to "reduced pollution from electricity generation".
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.
Purity is usually reported as an HPLC area percentage, most often measured at 214 nm. Identity is confirmed separately by mass spectrometry. A certificate of analysis should state both the method and the observed value.