This is a working overview of reversed-phase HPLC, written for readers who want more than a one-paragraph summary but less than a textbook.
This page was last updated on 2025-08-21 and is reviewed periodically as new material appears.
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.
Most published work on selank originates from a small number of research groups in the Russian Federation. A large share of that record appears in Russian-language journals, which limits access for readers who rely on English-indexed databases. Independent replication by laboratories outside the original research network is sparse in publicly available sources. This concentration of origin and language is a frequently noted feature when the compound is summarized in broader reviews of synthetic peptides.
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.
| Property | Value | Notes |
|---|---|---|
| Molecular formula | C33H57N11O9 | Derived from the seven-residue sequence |
| Molecular weight | About 751.9 g/mol | Average mass; the monoisotopic value is slightly lower |
| Residue count | Seven amino acids | Thr-Lys-Pro-Arg-Pro-Gly-Pro |
| Parent compound | Tuftsin (Thr-Lys-Pro-Arg) | Selank extends tuftsin at the C-terminus |
| Compound class | Synthetic short peptide | Studied in a research setting; not a licensed drug in most markets |
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.
Peptide bonds in selank are susceptible to hydrolysis under strongly acidic or basic conditions, and the terminal proline residues are vulnerable to exopeptidase activity in biological samples. Lyophilized powder stored dry at -20 °C typically remains stable for extended periods, whereas aqueous solutions degrade faster and may lose measurable purity within days to weeks depending on pH, temperature, and microbial load. Repeated freeze-thaw cycles promote aggregation and adsorption to container surfaces. For analytical work, solutions are usually prepared fresh, kept cold, and used within a single working day.
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.
Selank is a synthetic heptapeptide developed in Russia as a structural analogue of tuftsin, a naturally occurring immunomodulatory tetrapeptide. Its sequence, Thr-Lys-Pro-Arg-Pro-Gly-Pro, keeps the tuftsin core at the N-terminus and appends a Pro-Gly-Pro tail. Researchers at the Institute of Molecular Genetics in Moscow synthesized the compound during the 1990s while searching for peptides with combined anxiolytic and immunomodulatory activity. The added tail was intended to resist enzymatic cleavage and prolong the molecule's presence in circulation.
Belizean cuisine reflects the country's multicultural makeup, incorporating elements from Mestizo, Creole, Garifuna, Maya, and immigrant influences, including Chinese and Indian traditions. This unique combination makes Belizean food an amalgamation of flavours from Central America, the Caribbean, and further afield, producing dishes that are at once familiar to these areas yet distinctly Belizean. Breakfast is often hearty, featuring staples like bread, flour tortillas, or fry jacks (fried dough pieces), which are typically paired with cheese, refried beans, and eggs, along with coffee or tea. Street vendors frequently offer breakfast options such as tacos and meat pies, while a midday meal, known locally as "dinner," serves as the main meal of the day. Traditional midday dishes include rice and beans (with or without coconut milk), stewed chicken, tamales, escabeche (an onion soup), and panades (fried corn shells with beans or fish). In rural areas, meals often centre around locally grown maize, beans, and squash, particularly in Maya communities, whereas Garifuna cuisine is known for its Afro-Caribbean roots and heavily features seafood and cassava-based dishes like ereba (cassava bread). These local ingredients and cooking methods provide a connection to the land and traditions. This culinary diversity is supported by Belize's abundant agriculture, which allows for a wide variety of fresh ingredients, from tropical fruits to seafood. The nation has numerous restaurants and fast-food establishments, including lower-cost options.
=== Infection === Common infectious causes of back pain include osteomyelitis, septic discitis, paraspinal abscess and epidural abscess. Infectious causes that lead to back pain involve various structures surrounding the spine. Osteomyelitis is the bacterial infection of the bone. Vertebral osteomyelitis is most commonly caused by staphylococci. Risk factors include skin infection, urinary tract infection, IV catheter use, IV drug use, previous endocarditis and lung disease. Spinal epidural abscess is commonly caused by severe infection with bacteremia. Risk factors include recent administration of epidurals, IV drug use or recent infection.
== J == Jacobsen epoxidation Jacobsen rearrangement Janovsky reaction Japp–Klingemann reaction Japp–Maitland condensation Jocic reaction Johnson–Claisen rearrangement Johnson–Corey–Chaykovsky reaction Jones oxidation Jordan–Ullmann–Goldberg synthesis Julia olefination, Julia–Lythgoe olefination
This test showed the compound later named fluoxetine to be the most potent and selective inhibitor of serotonin reuptake of the series. Introduction of fluoxetine to the market is hailed as a miracle drug for the treatment of depression because it had fewer adverse effects, simpler dosing strategies and greater margin of safety when overdoses were consumed and thus it had better adherence, compared to the older antidepressants (TCAs and MAOIs). Fluoxetine paved the way for the next generation of SSRIs, serving as a prototype for them. Since then the number of drugs in the SSRI class has become bigger and there are now six (fluoxetine, paroxetine, citalopram, escitalopram, sertraline, and fluvoxamine), as demonstrated in table 1.
== Current Research and Future Implications == Currently, studies and experiments are being done to test for dedifferentiation-like abilities in mammalian cells, with hopes that this information can provide more insight into possible regenerative abilities in mammals. Dedifferentiation could spark innovation in regenerative medicine because it suggests that one's own cells can change cell fates, which would remove immunological response risks from treatment with allogeneic cells, or cells that are not genetically matched with the patient. A concept that has been explored for mammals is that of inducible dedifferentiation, which would make cells that do not naturally dedifferentiate be able to revert to a pluripotent or progenitor-like state. This is achieved by expressing the appropriate transcription factors in the cell and suppressing others. More information about this as well as the possible risks can be found here [1] .
Sources: en.wikipedia.org
London's King's Cross railway station is temporarily closed due to overcrowding as passengers are warned not to travel by train because of disruptions caused by Storm Babet. Police launch an investigation after three men escape from HM Prison Hollesley Bay on the same day. 22 October – Storm Babet: Residents of 500 properties in Retford, Nottinghamshire are urged to evacuate as Nottinghamshire County Council declares a major flooding incident. 27 October – Sixteen people, including a prison health worker, are sentenced to prison for their part in a drugs smuggling ring operating at HM Prison Lindholme. Instances of antisemitic crime have continued to increase in London since the start of the Israel–Hamas conflict, with 408 cases occurring since 1 October, compared to 28 for the same period in 2022. 28 October – The Priory Meadow Shopping Centre in Hastings is evacuated after rain causes heavy flooding in the town. Nottingham Panthers forward Adam Johnson dies after receiving a serious cut to the neck from an ice skate during a match with the Sheffield Steelers. Cars and property are damaged after a tornado strikes Littlehampton in West Sussex. 29 October – Nine people are taken to hospital after a car crashes into a bus stop in Aldwych, central London. 30 October – Ealing Central Library is closed temporarily after bed bugs are discovered in the furnishings.
Tetrahymanol is a gammacerane-type membrane lipid first found in the marine ciliate Tetrahymena pyriformis. It was later found in other ciliates, fungi, ferns, and bacteria. After being deposited in sediments that compress into sedimentary rocks over millions of years, tetrahymanol is dehydroxylated into gammacerane. Gammacerane has been interpreted as a proxy for ancient water column stratification.
According to regulatory requirements, water phantom testing must be performed approximately every three months to ensure that the radiation dose delivered by the treatment system is consistent with the radiation planning. The Alderson-Rando phantom, invented by Samuel W. Alderson (1914-2005), has become the standard X-ray phantom. It was followed by the Alderson Radio Therapy (ART) phantom, which he patented in 1967. The ART phantom is cut horizontally into 2.5 cm thick slices. Each slice has holes sealed with bone-equivalent, soft-tissue-equivalent, or lung-equivalent pins that can be replaced by thermoluminescent dosimeters. Alderson is also known as the inventor of the crash test dummy.
In some archaea, i.e. members of the Methanobacteriales and in the genus Methanopyrus, pseudopeptidoglycan (pseudomurein) has been found. In pseudopeptidoglycan the sugar residues are β-(1,3) linked N-acetylglucosamine and N-acetyltalosaminuronic acid. This makes the cell walls of such archaea insensitive to lysozyme. The biosynthesis of pseudopeptidoglycan has been described.
Van Krevelen diagrams are graphical plots developed by Dirk Willem van Krevelen (chemist and professor of fuel technology at the TU Delft) and used to assess the origin and maturity of kerogen and petroleum. The diagram cross-plots the hydrogen:carbon atomic ratio as a function of the oxygen:carbon atomic ratio. Beginning around 2003, the diagrams are often used to visualize data from mass spectrometry analysis, used for mixtures other than kerogen and petroleum. For example, the diagrams have been used in one analysis of the components in Scotch whiskey, and are used in characterizing Dissolved organic carbon (DOC) in waters and soils
Sources: en.wikipedia.org
== Fare == Their menu included at least 18 varieties of pizza, along with various other foods. When it was based in Scottsdale, the chain had 112 restaurants open or under development in Arizona, Alabama, California, Utah, Oregon, Washington, Idaho, Florida, Mississippi, North Carolina, Tennessee, Ohio and New Mexico, and Puerto Rico.
=== Engineered Bacteria Therapeutics === Fischbach's team has made significant strides in engineering commensal bacteria for therapeutic purposes. They transformed the ubiquitous skin bacterium Staphylococcus epidermidis into a topical vaccine platform. This approach generated potent, durable, and specific antibody responses in mice, potentially offering a new method for vaccine delivery. In 2023, his postdoc Erin Chen led an effort to engineer skin bacteria to induce antitumor T cell responses against melanoma, highlighting the potential of the skin microbiome in cancer immunotherapy.
=== 20th–21st century === After receiving greater financial autonomy in 1907, it began a new phase of growth. In 1934, the MNHN opened the Paris Zoological Park, a new zoo to in the Bois de Vincennes, as the home for the larger animals of the Menagerie of the Jardin des Plantes. In 1937, it opens the Musée de l'Homme, a museum of anthropology located in Palais de Chaillot, across the Seine from the Eiffel Tower, in a building created for the 1937 Paris International Exposition. In recent decades, it has directed its research and education efforts at the effects on the environment of human exploitation. In French public administration, the museum is classed as a grand établissement of higher education. Some of the buildings, particularly the Grand Gallery of Evolution, completed in 1889, were in poor condition by the mid-20th century. It was closed entirely in 1965, then underwent major restoration between 1991 and 1994 to its present state. In August 2025, the MNHN returned the skull of the Malagasy King Toera of Menabe, who was killed by French colonial soldiers in 1897, to Madagascar along with the skulls of two of his companions after more than a century of keeping the skulls in its archives. On 16 September 2025, multiple gold artefacts valued at €600,000 were stolen following a heist at the MNHN. A suspect was charged on 21 October 2025 in connection with the heist.
Building this hyphenated MS/IRMS hybrid was supported by Finnigan MAT (as then was) and Dr Willie Brand (Finnigan MAT) who designed and built the interface for splitting the flow from the gas chromatograph in the ratio needed to meet specifications and requirement of both the ion trap mass spectrometer and the Delta S isotope ratio mass spectrometer. From 2010 to 2014 he served as Director of the Forensic Isotope Ratio Mass Spectrometry Network (FIRMS). while from 2009 to 2013 he was a Council member of the British Association for Human Identification (BAHID). He was one of the scientists consulted by the Garda Síochána investigating the case of the dismembered torso found in the Dublin Royal Canal. This case gained notoriety under the name Scissor Sisters. He was also one of the scientists consulted by the police investigating the Norfolk headless body case. Most recently Meier-Augenstein was involved with the investigation of the death of Lamduan Armitage dubbed "The Lady of the Hills" and the "Thai Bride". His interpretation of stable isotopic signatures obtained from remains of the murder victim corroborated one line of investigation that the victim might have grown up in Thailand. A subsequently launched public appeal received a response from a Thai family who believed the victim could be their daughter. DNA tests finally confirmed the identity of the victim as Lamduan Armitage, née Seekanya, originally from Thailand who had moved to the UK in 1991.
Sources: en.wikipedia.org
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.
Tuftsin contains four residues, while selank carries an additional Pro-Gly-Pro segment at the carboxyl end. That extension is intended to reduce enzymatic cleavage. Comparative pharmacokinetic data in humans remain limited.
No single receptor target is widely accepted as the definitive mediator of the reported effects. Proposed contributors include GABAergic modulation, shifts in monoamine turnover, and altered neuropeptide degradation. The mechanism is treated in the literature as unresolved.
Dry powder is best kept sealed, protected from light, and held at minus 20 degrees Celsius or below. Desiccant packaging helps limit moisture uptake because the material is hygroscopic. A sealed vial should be allowed to equilibrate to room temperature before opening to reduce condensation.