The short version of lyophilization fits in a sentence. The long version — which is the one that helps — is below.
Reviewed 2025-08-02. Anything still debated is marked as such rather than presented as settled.
Characterization of Selank in laboratory settings relies on standard peptide analytical techniques. Reverse-phase high-performance liquid chromatography separates the peptide from related impurities and degradation products, while mass spectrometry confirms molecular identity through accurate mass measurement. Amino acid analysis and peptide sequencing verify the primary structure when reference material is unavailable. Because Selank is a short chain, fragmentation-based analysis produces a diagnostic ion pattern that supports confident identification.
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.
Development work on the compound began in the 1980s and 1990s at the Institute of Molecular Genetics in Moscow, within the same research programme that produced the peptide Semax. Early investigators sought a tuftsin derivative with improved resistance to enzymatic breakdown and with activity in the central nervous system after peripheral administration. Most of the primary literature from this period was published in Russian, a factor that still shapes how easily the findings can be checked by outside groups.
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.
| 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 |
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.
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.
Laboratory work relies on standard behavioral paradigms. Rodents are tested in the elevated plus maze, open field, and passive avoidance tasks, with outcomes compared against diazepam or vehicle controls. Intranasal dosing is used most often because it bypasses first-pass metabolism, though intraperitoneal and intravenous routes also appear in published protocols. Biochemical endpoints include tissue BDNF concentrations, cytokine levels, and monoamine metabolites. Human data are limited to small Russian trials reporting reduced anxiety scores; most were not prospectively registered, and few employed independent outcome assessment.
Measuring peptide exposure inside the brain is technically difficult. Selank is degraded rapidly in plasma, and assays must separate intact peptide from fragments, which favors targeted mass spectrometry over immunoassays alone. Reported half-lives are short, on the order of minutes, so effects observed hours later are attributed to downstream signaling rather than to the parent compound. Blood-brain barrier permeability is debated and rarely quantified directly. Gaps include absent dose-response characterization, inconsistent reporting of purity, and almost no pharmacokinetic data from human participants.
=== Breast cancer === Anastrozole is used in the treatment and prevention of breast cancer in women. The Arimidex, Tamoxifen, Alone or in Combination (ATAC) trial was of localized breast cancer and women received either anastrozole, the selective estrogen receptor modulator tamoxifen, or both for five years, followed by five years of follow-up. After more than 5 years the group that received anastrozole had better results than the tamoxifen group. The trial suggested that anastrozole is the preferred medical therapy for postmenopausal women with localized estrogen receptor-positive breast cancer.
==== Cave 60: "Largest Cave" ==== Cave 60, also called the "Largest Cave", is a cave which was expanded over several periods, and still contained a few paintings belonging to the refined style of the Classical First Period, while most of the paintings are from the later Second Period. The cave is known for its portrait of royal donors, characteristically accompanied by a label in Brahmi script. This is the only known possible instance of a portrait of royal donors in a painting of the First Style, whereas they occur very often during the second period. The style of painting is very similar to that seen in the Cave of the Painters (Cave 207). The hairstyle of the male donor is quite similar to that of the famous painter in the Cave of the Painters. The cave is also remarkable for the presence of Sasanian-style ducks in a bead roundel frames, a well-known motif which spread through Central Asia, and is known from the dress of a Central Asian ambassador from Afrasiab. This motif was likely painted later than the portraits of the royal donors.
In 1943, astatine was found as a product of two naturally occurring decay chains by Berta Karlik and Traude Bernert, first in the so-called uranium series, and then in the actinium series. (Since then, astatine was also found in a third decay chain, the neptunium series.) Friedrich Paneth in 1946 called to finally recognize synthetic elements, quoting, among other reasons, recent confirmation of their natural occurrence, and proposed that the discoverers of the newly discovered unnamed elements name these elements. In early 1947, Nature published the discoverers' suggestions; a letter from Corson, MacKenzie, and Segrè suggested the name "astatine" coming from the Ancient Greek ástatos (ἄστατος) meaning 'unstable', because of its propensity for radioactive decay, with the ending "-ine", found in the names of the four previously discovered halogens. The name was also chosen to continue the tradition of the four stable halogens, where the name referred to a property of the element. Corson and his colleagues classified astatine as a metal on the basis of its analytical chemistry. Subsequent investigators reported iodine-like, cationic, or amphoteric behavior. In a 2003 retrospective, Corson wrote that "some of the properties [of astatine] are similar to iodine ... it also exhibits metallic properties, more like its metallic neighbors Po and Bi."
Half & Half is an American television sitcom created by Jeffrey Klarik and executive-produced by Yvette Lee Bowser through her Sister Lee Productions banner that aired on UPN from September 23, 2002, to May 15, 2006 (related to the Fox comedy show, Living Single that aired out in 1993 until 1998). It was co-produced by CBS Studios under one of its former aliases, Eye Productions, Inc. Set in San Francisco, California, the show centers on the lives of two paternal half-sisters in their early adulthood who were estranged throughout their childhood, and are finally developing a close relationship. The show was the second-most-watched on UPN's Monday night line-up (next to Girlfriends) and fourth overall on the network. The series was almost renewed for a fifth season by UPN's successor network, The CW, but due to several circumstances — including the network's contractual obligation to pick up Reba, the last-minute renewal of All of Us, and the pick-up of the Girlfriends spin-off The Game — the series was left off the network's Autumn 2006 schedule and canceled. Outside of the United States, the series has aired in reruns on Global TV in Canada, Trouble in the United Kingdom and in local syndication channels in the United States, including Bounce TV, TV One, Cleo TV, BET Her and Dabl. The series is available to stream on Paramount+ and Amazon Prime Video.
Sources: en.wikipedia.org
=== Persistence in the environment and accumulation in the food chain === DDT was the first organic insecticide. It was introduced during WW2, and was widely used. One use was vector control and it was sprayed on open water. It degrades slowly in the environment, and it is lipophilic (fat soluble). It became the first global pollutant, and the first pollutant to accumulate and magnify in the food chain. During the 1950s and 1960s these very undesirable side effects were recognized, and after some often contentious discussion, DDT was banned in many countries in the 1960s and 1970s. Finally in 2001 DDT and all other persistent insecticides were banned via the Stockholm Convention. Since many decades the authorities require new insecticides to degrade in the environment and not to bioaccumulate.
The secession of the Liberal Republican Union in March 1926, and the beginning of the Ditadura Nacional at the end of May of the same year, marked the end of the Nationalist Republican Party. In the early 1930s many former members of the PRN joined the National Union, ruling party of the Estado Novo.
His government pushed to increase its use and the number of TCM-trained doctors and announced that students of TCM would no longer be required to pass examinations in Western medicine. Chinese scientists and researchers, however, expressed concern that TCM training and therapies would receive equal support with Western medicine. They also criticized a reduction in government testing and regulation of the production of TCMs, some of which were toxic. Government censors have removed Internet posts that question TCM. In 2020 Beijing drafted a local regulation outlawing criticism of TCM. According to Caixin, the regulation was later passed with the provision outlawing criticism of TCM removed. Traditional Chinese Medicine does not reflect ancient medical practice, instead being a modern selection from very diverse traditions, with "a minimal vestige of ideas and practices" having been retained from them.
Alexios' concentration of power in the hands of his Komnenos dynasty meant the most serious political threats came from within the imperial family—before his coronation, John II had to overcome his mother Irene and his sister Anna, and the primary threat during his reign was his brother Isaac. John campaigned annually and extensively—he fought the Pechenegs in 1122, the Hungarians in the late 1120s, and the Seljuks throughout his reign, waging large campaigns in Syria in his final years—but he did not achieve large territorial gains. In 1138, John raised the imperial standard over the Crusader Principality of Antioch to intimidate the city into allying with the Byzantines, but did not attack, fearing that it would provoke western Christendom to respond. Manuel I used the considerable financial resources left by his father in pursuit of his ambitions, and also to secure the empire's position in an increasingly multilateral geopolitical landscape. Through a combination of diplomacy and subsidies, he cultivated a network of allies and client rulers around the empire: the Turks of the Sultanate of Rum, the Kingdom of Hungary, the Cilician Armenians, Balkan princes, Italian and Dalmatian cities, and most importantly Antioch and the Crusader States, marrying one of their princesses in 1161. Manuel managed the difficult passage of the Second Crusade through Byzantine territories in 1147, but the campaign's failure was blamed on the Byzantines by western contemporaries.
=== Anti-inflammatory and analgesic agents === Glucocorticoids can be used in the short term and at the lowest dose possible for flare-ups and while waiting for slow-onset drugs to take effect. Combination of glucocorticoids and conventional therapy has shown a decrease in rate of erosion of bones. Steroids may be injected into affected joints during the initial period of RA, before the use of DMARDs or oral steroids. Non-NSAID drugs to relieve pain, like paracetamol may be used to help alleviate the pain symptoms; they do not change the underlying disease. The use of paracetamol may be associated with the risk of developing ulcers. NSAIDs reduce both pain and stiffness in those with RA but do not affect the underlying disease and appear to have no effect on people's long term disease course and thus are no longer first line agents. NSAIDs should be used with caution in those with gastrointestinal, cardiovascular, or kidney problems. Rofecoxib was withdrawn from the global market as its long-term use was associated to an increased risk of heart attacks and strokes. Use of methotrexate together with NSAIDs is safe, if adequate monitoring is done. COX-2 inhibitors, such as celecoxib, and NSAIDs are equally effective. A 2004 Cochrane review found that people preferred NSAIDs over paracetamol. However, it is yet to be clinically determined whether NSAIDs are more effective than paracetamol. The neuromodulator agents, topical capsaicin, may be reasonable to use in an attempt to reduce pain.
Sources: en.wikipedia.org
== Melamine on metal surfaces == It is reported that melamine molecules adsorbed on gold or silver surface tend to arrange into honeycomb or closed-packed structures. Such a self-assembly occurs due to the inter-molecular hydrogen bond interaction. This ordering was further investigated using classical Monte Carlo and DFT methods.
== Mechanism of action == Generally, a proportion of immature thymus-derived lymphocytes differentiate into mature CD4+ T-cells which produce a certain amount of cytokines, such as interleukin-2 (IL-2) and gamma interferon. To attack tumor cells and viruses, CD-4 cells coordinate the overall immune response and help activate CD8 T-lymphocytes. Often called “effector” or “cytotoxic” T-cells, CD-8+ T-lymphocytes they respond to intracellular pathogens and cancer cells. Under viral attack CD-4+ T-cells fail to mature, fail to produce IL-2 and gamma interferon, and consequently fail to coordinate CD-8 responses to viruses. LTCI increases the production of CD-4+ T-cells and can subsequently overcome this immunosuppression.
In addition, high-resolution cryo-EM structures of a thermophilic eukaryotic 80S ribosome captured in two rotational states at ~2.9 Å and ~3.0 Å resolution revealed atomistic details of the eukaryotic translocation mechanism and conformational dynamics of eEF2 during GTP hydrolysis.
The word "GULAG" is an acronym for Glavnoe Upravlenie Lagerei, or Main Camp Administration, the institution which ran the Soviet camps. But over time, the word has also come to signify the system of Soviet slave labor itself, in all its forms and varieties: labor camps, punishment camps, criminal and political camps, women's camps, children's camps, transit camps. Even more broadly, "Gulag" has come to mean the Soviet repressive system itself, the set of procedures that Alexander Solzhenitsyn once called "our meat grinder": the arrests, the interrogations, the transport in unheated cattle cars, the forced labor, the destruction of families, the years spent in exile, the early and unnecessary deaths.
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.
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.