The short version of RP-HPLC fits in a sentence. The long version — which is the one that helps — is below.
Reviewed 2026-08-01. Anything still debated is marked as such rather than presented as settled.
Characterization of Selank in a laboratory setting relies on standard peptide methods. Reverse-phase high-performance liquid chromatography separates the target from related impurities and provides a purity figure, commonly reported as 95 percent or higher. Mass spectrometry, typically electrospray ionization or matrix-assisted laser desorption, confirms the molecular mass and helps detect truncation or modification. Amino acid analysis can verify composition when a sequence-level check is needed. These techniques together establish identity and purity for a given lot.
Lyophilized Selank, the dry powder form, is generally stored frozen at minus 20 degrees Celsius or colder for long-term keeping. The solid is hygroscopic and should stay sealed, dry, and protected from light. Once dissolved, the peptide is less stable and is usually held refrigerated at 2 to 8 degrees Celsius for short periods. Repeated freezing and thawing is avoided because it can promote aggregation and loss of activity. Buffers and pH choice also affect how long a solution remains usable.
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.
| Property | Value | Notes |
|---|---|---|
| Solubility | Freely soluble in water | Also in aqueous buffers |
| Typical purity (HPLC) | 95 percent or higher | Lot-dependent |
| Dry powder storage | Minus 20 degrees Celsius | Sealed, dry, protected from light |
| Solution storage | 2 to 8 degrees Celsius | Short-term use |
| Identity confirmation | Mass spectrometry | ESI or MALDI-TOF |
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.
Naming conventions place Selank in the same research family as Semax, another Russian-developed peptide investigated for cognitive effects. The two compounds share a lineage but differ in sequence and in the biological systems proposed as their targets. Semax descends from ACTH fragments, whereas Selank descends from tuftsin. Publications sometimes identify Selank by its full peptide sequence or by laboratory codes rather than one uniform trade name. Because replication outside Russia is limited, reports on its properties are best read alongside the study design and the purity of the material tested.
Selank is a synthetic heptapeptide developed in Russia during the 1990s. Researchers at the Institute of Molecular Genetics of the Russian Academy of Sciences designed it as a stabilized analog of tuftsin, a naturally occurring immunomodulatory tetrapeptide. The compound has been studied primarily for its reported anxiolytic and nootropic effects. It remains largely unknown in Western pharmacology and is not approved as a medicine by major regulators such as the FDA or the EMA.
In the early years of using the technique, it was understood that it depended on the atmospheric 14C/12C ratio having remained the same over the preceding few thousand years. To verify the accuracy of the method, several artefacts that were datable by other techniques were tested; the results of the testing were in reasonable agreement with the true ages of the objects. Over time, however, discrepancies began to appear between the known chronology for the oldest Egyptian dynasties and the radiocarbon dates of Egyptian artefacts. Neither the pre-existing Egyptian chronology nor the new radiocarbon dating method could be assumed to be accurate, but a third possibility was that the 14C/12C ratio had changed over time. The question was resolved by the study of tree rings: comparison of overlapping series of tree rings allowed the construction of a continuous sequence of tree-ring data that spanned 8,000 years. (Since that time the tree-ring data series has been extended to 13,900 years.) In the 1960s, Hans Suess was able to use the tree-ring sequence to show that the dates derived from radiocarbon were consistent with the dates assigned by Egyptologists. This was possible because although annual plants, such as corn, have a 14C/12C ratio that reflects the atmospheric ratio at the time they were growing, trees only add material to their outermost tree ring in any given year, while the inner tree rings don't get their 14C replenished and instead start losing 14C through decay. Hence each ring preserves a record of the atmospheric 14C/12C ratio of the year it grew in.
Geochronology is the science of determining the age of rocks, fossils, and sediments using signatures inherent in the rocks themselves. Absolute geochronology can be accomplished through radioactive isotopes, whereas relative geochronology is provided by tools such as paleomagnetism and stable isotope ratios. By combining multiple geochronological (and biostratigraphic) indicators the precision of the recovered age can be improved. Geochronology is different in application from biostratigraphy, which is the science of assigning sedimentary rocks to a known geological period via describing, cataloging and comparing fossil floral and faunal assemblages. Biostratigraphy does not directly provide an absolute age determination of a rock, but merely places it within an interval of time at which that fossil assemblage is known to have coexisted. Both disciplines work together hand in hand, however, to the point where they share the same system of naming strata (rock layers) and the time spans utilized to classify sublayers within a stratum. The science of geochronology is the prime tool used in the discipline of chronostratigraphy, which attempts to derive absolute age dates for all fossil assemblages and determine the geologic history of the Earth and extraterrestrial bodies.
The Romanian revolution (Romanian: Revoluția română) was a period of violent civil unrest in the Socialist Republic of Romania during December 1989 as a part of the revolutions of 1989 that occurred in several countries around the world, primarily within the Eastern Bloc. The Romanian revolution started in the city of Timișoara and soon spread throughout the country, ultimately culminating in the drumhead trial and execution of longtime Romanian Communist Party (PCR) General Secretary Nicolae Ceaușescu and his wife Elena, and the end of 42 years of Communist rule in Romania. It was also the last removal of a Marxist–Leninist government in a Warsaw Pact country during the events of 1989, and the only one that violently overthrew a country's leadership and executed its leader; according to estimates, over one thousand people died and thousands more were injured. Following World War II, Romania found itself inside the Soviet sphere of influence, with Communist rule officially declared in 1947. In April 1964, when Romania published a general policy paper worked out under Gheorghe Gheorghiu-Dej's instructions, the country was well on its way of carefully breaking away from Soviet control. Nicolae Ceaușescu became the country's leader the following year. Under his rule, Romania experienced a brief waning of internal repression that led to a positive image both at home and in the West. However, repression again intensified by the 1970s, and Ceaușescu's regime eventually became one of the most repressive in the world and one of the most repressive of modern times.
In addition to his third share of the 1962 Nobel Prize for Physiology or Medicine, he received many awards and honours, including the Royal and Copley medals of the Royal Society (1972 and 1975), and also the Order of Merit (on 27 November 1991); he refused an offer of a CBE in 1963, but was often referred to in error as 'Sir Francis Crick' and even on occasions as 'Lord Crick'. He was elected an EMBO Member in 1964. The award of Nobel Prizes to John Kendrew and Max Perutz, and to Crick, Watson, and Wilkins was satirised in a short sketch in the BBC TV programme That Was The Week That Was with the Nobel Prizes being referred to as 'The Alfred Nobel Peace Pools'. He was an elected member of the American Academy of Arts and Sciences (1962), the United States National Academy of Sciences (1969), and the American Philosophical Society (1972).
Sources: en.wikipedia.org
officer and member of the Fire Squad who can also transform into Premiere Deka Red and appears exclusively in the direct-to-video anniversary special Tokusou Sentai Dekaranger 20th: Fireball Booster. Rui Edogawa is portrayed by Leo Nagatsuma (長妻 怜央, Nagatsuma Reo). Ridomihan Mokumisu (リドミハ星人モクミス, Ridomiha Seijin Mokumisu): A botanical garden curator from Planet Ridomiha who appears exclusively in the direct-to-video anniversary special Tokusou Sentai Dekaranger 20th: Fireball Booster. Mokumisu is voiced by Ayano Kawamura (川村 文乃, Kawamura Ayano), who also portrays her human form. Yoshiwan Raenjo (ヨシワ星人ラエンジョ, Yoshiwa Seijin Raenjo): Tarewarane's wife from Planet Yoshiwa who appears exclusively in the direct-to-video anniversary special Tokusou Sentai Dekaranger 20th: Fireball Booster. Sometime prior to the special, she betrayed Tarewarane to the Space Police to flee his domestic violence. Raenjo is portrayed by Mei Kurokawa (黒川 芽以, Kurokawa Mei). Jiujissonian Rotmen (ジウジッソ星人ロットメン, Jiujisso Seijin Rottomen): Tarewarane's right-hand man from Planet Jiujisso who possesses the ability to assume an alien child form under the alias of Marple (マープル, Māpuru) and appears exclusively in the direct-to-video anniversary special Tokusou Sentai Dekaranger 20th: Fireball Booster. Following Tarewarane's deletion, Rotmen takes over his boss's plans and takes Rakamu hostage to use Raenjo as his pawn. However, his plans are eventually foiled by the Dekarangers and he is deleted by Ban / Premiere Deka Red. Rotmen is voiced by Jun Fukuyama (福山 潤, Fukuyama Jun).
"Any Song" by R&B and rap artist Zico became number one on the Korean music charts due to the popularity of the #anysongchallenge, where users dance to the choreography of the song. The platform has also launched many songs that failed to garner initial commercial success into sleeper hits, particularly since the outbreak of the COVID-19 pandemic. However, it has received criticism for not paying royalties to artists whose music is used on the platform. Classic stars are able to connect with younger audiences born decades after a musician's first debut and across traditional genres. In 2020, Fleetwood Mac's "Dreams" was used in a skating video and a recreation by Mick Fleetwood. The song re-entered Billboard Hot 100 after 43 years and topped Apple Music. In 2022, Kate Bush's "Running Up That Hill" went viral among fans of Stranger Things, topping the UK singles chart 37 years after its original release. In 2023, Kylie Minogue's "Padam Padam" entered the Radio 1 playlist after being shared by Gen Z, although many youth radio stations refused to play the song. Other older artists with strong engagement on TikTok include Elton John and Rod Stewart. In Japan, artists from the 1970s to 1990s, such as Kohmi Hirose, Yōko Oginome, Akina Nakamori, Seiko Matsuda, Momoe Yamaguchi and Saki Kubota, have become popular on TikTok during the Showa (and early Heisei) retro boom.
Dexcom, Inc. is an American multinational healthcare company that develops, manufactures, produces and distributes a line of continuous glucose monitoring (CGM) systems for diabetes management. It operates internationally with global headquarters and R&D center in San Diego, California, U.S., and manufacturing facilities in Mesa, Arizona, U.S.; Batu Kawan, Malaysia; and Athenry, County Galway, Ireland.
In Urgenda v State of Netherlands the Dutch Supreme Court held the Dutch government must reduce greenhouse gas emissions by 25% before 2020, following the IPCC 2007 minimum recommendations, and that failure to do so would violate the right to life and home in ECHR articles 2 and 8. In the Klimaschutz case, the German Constitutional Court held that the German government must speed up its climate protection measures to protect the rights to life, and the environment under the Grundgesetz 1949, articles 2 and 20a. However the EU and member states have so far failed to codify liability to prevent pollution and climate damage by corporations that profit, and the EU Emissions Trading System has failed to adequately price carbon for the damage it causes (prices traded under €98 per metric ton until the end of 2022).
[A]n overwhelming preponderance of power [...] will remain wholly unattainable unless the Allies win the present war and the United States assumes responsibilities commensurate with its power—in the war, in the peace after the war and in the maintenance and improvement of the new order after the peace. The necessary preponderance of power is unlikely to emerge from any international combination other than a permanent alliance of the United States, the British Commonwealth of Nations, and the French Republic, with the addition of such Latin American states and such European democracies as may care to join. Such a coalition, if stable and permanent, could put an end to the world balance of power and oblige outside powers to abandon the game of power politics. No other coalition presently in prospect would seem to offer any comparable hope. In 1941, Alfred Vagts wrote an article, titled "The United States and the Balance of Power," in which he recalled the words of Thomas Jefferson:
Sources: en.wikipedia.org
of a body is a measure of the resistance offered by an elastic body to deformation. For an elastic body with a single degree of freedom (DOF) (for example, stretching or compression of a rod), the stiffness is defined as
Research has been ongoing since the 1960s to determine the proportion of 14C in the atmosphere over the past 50,000 years. The resulting data, in the form of a calibration curve, is now used to convert a given measurement of radiocarbon in a sample into an estimate of the sample's calendar age. Other corrections must be made to account for the proportion of 14C in different types of organisms (fractionation), and the varying levels of 14C throughout the biosphere (reservoir effects). Additional complications come from the burning of fossil fuels, such as coal and oil, and from the above-ground nuclear tests done in the 1950s and 1960s. Because the time it takes to convert biological materials to fossil fuels is substantially longer than the time it takes for their 14C to decay below detectable levels, fossil fuels contain almost no 14C. As a result, beginning in the late 19th century, there was a noticeable drop in the proportion of 14C as the carbon dioxide generated from burning fossil fuels began to accumulate in the atmosphere. Conversely, nuclear testing increased the amount of 14C in the atmosphere, which reached a maximum in about 1965 of almost double the amount present in the atmosphere prior to nuclear testing. Measurement of radiocarbon was originally done by beta-counting devices, which counted the amount of beta radiation emitted by decaying 14C atoms in a sample.
== Ethics == Much debate surrounds the topic of human enhancement and the means used to achieve one's enhancement goals. Ethical attitudes toward human enhancement can depend on many factors such as religious affiliation, age, gender, ethnicity, culture of origin, and nationality. In some circles the expression "human enhancement" is roughly synonymous with human genetic engineering, but most often it is referred to the general application of the convergence of nanotechnology, biotechnology, information technology and cognitive science (NBIC) to improve human performance. Since the 1990s, several academics (such as some of the fellows of the Institute for Ethics and Emerging Technologies) have risen to become advocates of the case for human enhancement while other academics (such as the members of President Bush's Council on Bioethics) have become outspoken critics. Advocacy of the case for human enhancement is increasingly becoming synonymous with "transhumanism", a controversial ideology and movement which has emerged to support the recognition and protection of the right of citizens to either maintain or modify their own minds and bodies; so as to guarantee them the freedom of choice and informed consent of using human enhancement technologies on themselves and their children. Their common understanding of the world can be seen from a physicist perspective rather than a biological perspective. Based on the idea of technological singularity, human enhancement is merging with technological innovation that will advance post-humanism.
The European continental tradition (See: Realism) focused on humans within human-made environments, and included the so-called city symphony films such as Walter Ruttmann's Berlin: Symphony of a Metropolis (of which Grierson noted in an article that Berlin, represented what a documentary should not be); Alberto Cavalcanti's, Rien que les heures; and Dziga Vertov's Man with a Movie Camera. These films tend to feature people as products of their environment, and lean towards the avant-garde.
== Sources == Cytisine is extracted from the seeds of Cytisus laburnum L. (golden rain acacia), and is found in several genera of the subfamily Faboideae of the family Fabaceae, including Laburnum, Anagyris, Thermopsis, Cytisus, Genista, Retama and Sophora. Cytisine is thought to also be present in Gymnocladus of the subfamily Caesalpinioideae, although this has not been proven.
Sources: en.wikipedia.org
Reverse-phase HPLC is the usual method and gives a percentage purity value. Mass spectrometry then confirms the molecular mass. Together they provide a basic identity and purity profile for a lot.
Freeze-dried material is kept frozen, often at minus 20 degrees Celsius, and protected from light and moisture. Dissolved peptide is refrigerated for short-term use. Repeated freeze-thaw cycles are avoided.
A certificate of analysis typically lists purity by HPLC, the confirmed mass, appearance, and sometimes water or counter-ion content. It documents results for a specific batch. Details vary by supplier.
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.