The short version of reversed-phase HPLC fits in a sentence. The long version — which is the one that helps — is below.
Reviewed 2026-07-19. Anything still debated is marked as such rather than presented as settled.
Storage practice centres on limiting moisture, oxygen, and repeated temperature cycling. Freeze-dried powder is generally held desiccated at minus twenty degrees Celsius or colder and protected from light. Reconstituted solutions are markedly less stable, and the aspartate-glycine junction is prone to succinimide formation at neutral to mildly alkaline pH. Portioning material into single-use aliquots reduces degradation compared with repeated freeze-thaw cycles. Stability data specific to this tetrapeptide remain scarce, so most handling guidance is extrapolated from general peptide chemistry rather than measured directly.
Documentation accompanying research peptides usually includes a certificate of analysis listing the batch number, purity figure, and test methods applied. Buyers comparing suppliers should check whether the reported purity refers to chromatographic area or to a mass-balance calculation, because the two are not equivalent. Counter-ion content, residual solvents, and water content are sometimes omitted from such certificates even though they affect the actual peptide mass present. Independent verification through a second laboratory is the most direct way to confirm that a supplied material matches its label.
Published work on this compound consists mainly of in vitro experiments, animal studies, and small clinical investigations, a substantial share of which appeared in Russian-language journals. Sample sizes are generally small, control conditions differ between studies, and several endpoints rely on markers whose clinical meaning is itself debated. Reviews of the longevity field treat the peptide as an early example of telomerase-directed research rather than an established intervention. Regulatory treatment varies by country: some jurisdictions place it under prescription controls, others treat it as a laboratory material, and importation may be restricted regardless of local status.
Epitalon is a synthetic tetrapeptide whose sequence is alanine–glutamate–aspartate–glycine, commonly abbreviated AEDG. It was developed in Russia during the 1980s and 1990s by investigators associated with the St. Petersburg Institute of Bioregulation and Gerontology, who studied short peptides as regulators of gene expression and tissue function. The alternative spelling epithalon appears interchangeably in the literature, and the two names refer to the same molecule. Outside Russia it is encountered chiefly as a research chemical rather than a licensed medicine, and it holds no approval from the United States Food and Drug Administration or the European Medicines Agency.
The peptide is a synthetic analogue of epithalamin, a preparation extracted from bovine pineal glands. Investigators sought a short, chemically defined molecule that would reproduce some of the endocrine and gerontological observations attributed to the glandular extract. Proposed mechanisms centre on induction of telomerase activity, an effect reported in cultured human somatic cells in the early 2000s, together with influences on melatonin secretion and neuroendocrine regulation. Those mechanisms remain incompletely characterised, and the reported telomerase response has not been consistently reproduced by independent groups working in comparable systems.
| Property | Value | Notes |
|---|---|---|
| Appearance | White to off-white powder | Freeze-dried solid |
| Solubility class | Freely soluble in water | Aqueous buffers also suitable |
| Typical storage temperature | Minus 20 degrees Celsius or colder | Desiccated and light protected |
| Typical analytical method | RP-HPLC with UV detection | 214 nm on C18 column |
| Identity confirmation | Electrospray mass spectrometry | Sequence verified separately |
Regulatory treatment differs by country. No formulation of epitalon holds a marketing authorisation as a medicine in the United States or the European Union, where material sold for laboratory use is handled as a research chemical and is not intended for human consumption. In Russia, several short peptide preparations from the same institute's peptide series are registered medicinal products, and epitalon appears in that national context. Elsewhere it is frequently offered as a cosmetic ingredient, a category with lighter requirements. Advertising claims about longevity or disease prevention are restricted in most jurisdictions, which limits how sellers describe the compound.
Freeze-dried epitalon is normally kept at minus twenty degrees Celsius in a sealed, desiccated container, protected from light. Short excursions at ambient temperature during shipping are generally tolerated, but repeated warming and cooling cycles encourage moisture uptake, which shortens shelf life. Once dissolved, the peptide is far less stable than the solid: aqueous solutions are subject to hydrolysis and to deamidation at the aspartate and glutamate residues. Working solutions are therefore held refrigerated and used within days, and repeated freezing and thawing of the same vial is best avoided.
Material supplied for laboratory use is normally a lyophilised white to off-white powder that dissolves readily in water and in isotonic saline. Lyophilised cakes are hygroscopic and should be equilibrated to room temperature before opening to limit condensation on the solid. Solutions are typically prepared at milligram-per-millilitre concentrations and divided into single-use aliquots, because repeated freeze–thaw cycles degrade short peptides. Aqueous solutions are far less stable than the dry powder, and identity is usually verified by mass spectrometry alongside purity estimation from reversed-phase high-performance liquid chromatography.
Epitalon is a synthetic linear tetrapeptide with the sequence alanine–glutamate–aspartate–glycine, abbreviated AEDG. Its molecular formula is C14H22N4O9 and the calculated mass is approximately 390.35 g/mol. The compound is made by solid-phase peptide synthesis rather than extracted from tissue, although early work described it as a short fragment of a peptide fraction obtained from bovine pineal extract. In the research literature the spelling epitalon and the variant epithalone both appear, while AEDG is the standard code used in peptide nomenclature.
Several names circulate for the same molecule, including epitalon, epithalone, epithalamin tetrapeptide, and the sequence code AEDG. A CAS registry number, 307297-39-8, is commonly cited for it, though catalogue entries should be checked against supplier documentation because mislabelled records occur. In its usual form the peptide carries free amino and carboxyl termini and is neither glycosylated nor lipidated. Researchers distinguish the defined tetrapeptide from epithalamin itself, a crude pineal preparation containing many peptides that is not chemically characterised.
The radical shift in the connotation of "genetic engineering" from an emphasis on the inherited characteristics of people to the commercial production of proteins and therapeutic drugs was nurtured by Joshua Lederberg. His broad concerns since the 1960s had been stimulated by enthusiasm for science and its potential medical benefits. Countering calls for strict regulation, he expressed a vision of potential utility. Against a belief that new techniques would entail unmentionable and uncontrollable consequences for humanity and the environment, a growing consensus on the economic value of recombinant DNA emerged.
All chemical elements derive from stellar nucleosynthesis except for hydrogen and some helium and lithium. Basic chemical ingredients of life – the carbon–hydrogen molecule (CH), the carbon–hydrogen positive ion (CH+) and the carbon ion (C+) – can be produced by ultraviolet light from stars. Complex molecules, including organic molecules, form naturally both in space and on planets. Organic molecules on the early Earth could have had either terrestrial origins, with organic molecule synthesis driven by impact shocks or by other energy sources, such as ultraviolet light, redox coupling, or electrical discharges; or extraterrestrial origins (pseudo-panspermia), with organic molecules formed in interstellar dust clouds or in the solar nebula accumulating onto the planet.
Gestational trophoblastic disease like hydatidiform moles ("molar pregnancy") or choriocarcinoma may produce high levels of βhCG due to the presence of syncytiotrophoblasts, part of the villi that make up the placenta, and despite the absence of an embryo. This, as well as several other conditions, can lead to elevated hCG readings in the absence of pregnancy. hCG levels are also a component of the triple test, a screening test for certain fetal chromosomal abnormalities/birth defects. High hCG levels in the maternal serum could suggest Down syndrome, potentially due to continued hCG production by the placenta beyond the first trimester. A study of 32 normal pregnancies came to the result that a gestational sac of 1–3 mm was detected at a mean hCG level of 1150 IU/L (range 800–1500), a yolk sac was detected at a mean level of 6000 IU/L (range 4500–7500) and fetal heartbeat was visible at a mean hCG level of 10,000 IU/L (range 8650–12,200).
Actinium oxide (Ac2O3) can be obtained by heating the hydroxide at 500 °C (932 °F) or the oxalate at 1,100 °C (2,010 °F), in vacuum. Its crystal lattice is isotypic with the oxides of most trivalent rare-earth metals.
Butyrolactone, with its wide liquid range, chemical stability, and high dielectric constant, is used in electrolytic capacitors as the organic solvent. It has been used as a solvent in various laboratory experiments, e.g., the preparation of methylammonium lead halide. Another discovered GBL utility is in the synthesis of nicotine (analogs).
Sources: en.wikipedia.org
The Slovak National Uprising ("1944 Uprising") was an armed struggle between German Wehrmacht forces and rebel Slovak troops August–October 1944. It was centered at Banská Bystrica. The rebel Slovak Army, formed to fight the Germans, had an estimated 18,000 soldiers in August, a total which first increased to 47,000 after mobilisation on 9 September 1944, and later to 60,000, plus 20,000 partisans. However, in late August, German troops were able to disarm the Eastern Slovak Army, which was the best equipped, and thus significantly decreased the power of the Slovak Army. Many members of this force were sent to Nazi concentration camps; others escaped and joined partisan units. The Slovaks were aided in the Uprising by soldiers and partisans from the Soviet Union, United Kingdom, US, France, the Czech Republic, and Poland. In total, 32 nations were involved in the Uprising.
== External links == Media related to Alpha-synuclein at Wikimedia Commons alpha-Synuclein at the U.S. National Library of Medicine Medical Subject Headings (MeSH) Human SNCA genome location and SNCA gene details page in the UCSC Genome Browser.
The Supreme Central Junta was defeated and dissolved itself giving way to a five-member council know as the Regency, or the Council of Regency of Spain and the Indies. Next, to establish a more legitimate government system, the Regency called for the convening of an "extraordinary and general Cortes of the Spanish Nation": which was convened as the Cortes of Cádiz. At the beginning of 1810, new juntas appeared across Spanish America when the Central Junta fell to the French invasion. The Cortes of Cádiz was the first national assembly to claim sovereignty in Spain. It represented the abolition of the old kingdoms. The opening session was held on 24 September 1810, in the building now known as the Real Teatro de las Cortes under the siege of French army. It met as one body and its members represented the entire Spanish empire. The plan for the election of the Cortes, based on provinces, and not kingdoms, was more equitable and provided more time to determine what would be considered an overseas province.
== Education and career == Mechler earned a Diploma (BSc and MSc) in Chemistry and Physics in 1996, followed by a PhD in physics at the University of Szeged in 2001. Subsequently, he worked at the University of California, Santa Barbara, for three years, during which his research focus shifted to bioinspired materials and biomolecule interactions. In 2004, he moved to Australia to Monash University, where he established his independent research program focusing on biomolecule self-assembly, membrane biophysics, and peptide-membrane interactions while continuing to explore bioinspired materials and bioactive natural products. In 2009, Mechler joined La Trobe University as a Senior Lecturer in the Department of Chemistry, was later appointed associate professor in 2016, and has held the position of Professor since 2021. For his work, Mechler was honored with the Government of Australia Office of Learning and Teaching National Citation For Outstanding Student Learning in 2013 and was elected Fellow of the Royal Society of Chemistry in 2016.
Genome-based peptide fingerprint scanning (GFS) is a system in bioinformatics analysis that attempts to identify the genomic origin (that is, what species they come from) of sample proteins by scanning their peptide-mass fingerprint against the theoretical translation and proteolytic digest of an entire genome. This method is an improvement from previous methods because it compares the peptide fingerprints to an entire genome instead of comparing it to an already annotated genome. This improvement has the potential to improve genome annotation and identify proteins with incorrect or missing annotations.
Sources: en.wikipedia.org
Mammals are a diverse class of animals, mostly terrestrial but some are aquatic and others have evolved flapping or gliding flight. They mostly have four limbs, but some aquatic mammals have no limbs or limbs modified into fins, and the forelimbs of bats are modified into wings. The legs of most mammals are situated below the trunk, which is held well clear of the ground. The bones of mammals are well ossified and their teeth, which are usually differentiated, are coated in a layer of prismatic enamel. The teeth are shed once (milk teeth) during the animal's lifetime or not at all, as is the case in cetaceans. Mammals have three bones in the middle ear and a cochlea in the inner ear. They are clothed in hair and their skin contains glands which secrete sweat. Some of these glands are specialized as mammary glands, producing milk to feed the young. Mammals breathe with lungs and have a muscular diaphragm separating the thorax from the abdomen which helps them draw air into the lungs. The mammalian heart has four chambers, and oxygenated and deoxygenated blood are kept entirely separate. Nitrogenous waste is excreted primarily as urea. Mammals are amniotes, and most are viviparous, giving birth to live young. Exceptions to this are the egg-laying monotremes, the platypus and the echidnas of Australia. Most other mammals have a placenta through which the developing foetus obtains nourishment, but in marsupials, the foetal stage is very short and the immature young is born and finds its way to its mother's pouch where it latches on to a teat and completes its development.
The first U.S. Women's National Physique Championship, promoted by Henry McGhee and held in 1978 in Canton, Ohio, is generally regarded as the first true female bodybuilding contest—that is, the first contest where the entrants were judged solely on muscularity. In 1980, the first Ms. Olympia (initially known as the "Miss" Olympia), the most prestigious contest for professionals, was held. The first winner was Rachel McLish, who had also won the NPC's USA Championship earlier in the year. The contest was a major turning point for female bodybuilding. In 1985, the documentary Pumping Iron II: The Women was released. It documented the preparation of several women for the 1983 Caesars Palace World Cup Championship. Competitors prominently featured in the film were Kris Alexander, Lori Bowen, Lydia Cheng, Carla Dunlap, Bev Francis, and McLish. At the time, Francis was actually a powerlifter, though she soon made a successful transition to bodybuilding, becoming one of the leading competitors of the late 1980s and early 1990s. The related areas of fitness and figure competition increased in popularity, surpassing that of female bodybuilding, and provided an alternative for women who choose not to develop the level of muscularity necessary for bodybuilding. McLish would closely resemble what is thought of today as a fitness and figure competitor, instead of what is now considered a female bodybuilder. E. Wilma Conner competed in the 2011 NPC Armbrust Pro Gym Warrior Classic Championships in Loveland, Colorado, at the age of 75 years and 349 days.
=== Ukraine === A people's deputy of Ukraine (Ukrainian: народний депутат України, narodnyi deputat Ukrayiny) is a member of parliament or legislator elected by a popular vote to the Verkhovna Rada (the unicameral parliament of Ukraine). Often people's deputies of Ukraine are referred to simply as deputies. The main statutes that define the order of elections, rights and duties of the people's deputies of Ukraine are outlined in Articles 76–81 of the Constitution of Ukraine. There are 450 people's deputies of Ukraine who are elected based on the general, equal and direct electoral right for five years. The deputies may be appointed to various parliamentary positions such as the chairperson (speaker) of parliament, a head of a committee or a parliamentary faction, etc. Upon its appointment, to the office, each people's deputy of Ukraine receives a deputy mandate. People's deputies that run for parliament as self-nominated candidates can join factions if they wish.
Coagulative necrosis is characterized by the formation of a gelatinous (gel-like) substance in dead tissues in which the architecture of the tissue is maintained, and can be observed by light microscopy. Coagulation occurs as a result of protein denaturation, causing albumin to transform into a firm and opaque state. This pattern of necrosis is typically seen in hypoxic (low-oxygen) environments, such as infarction. Coagulative necrosis occurs primarily in tissues such as the kidney, heart and adrenal glands. Severe ischemia most commonly causes necrosis of this form. Liquefactive necrosis (or colliquative necrosis), in contrast to coagulative necrosis, is characterized by the digestion of dead cells to form a viscous liquid mass. This is typical of bacterial, or sometimes fungal, infections because of their ability to stimulate an inflammatory response. The necrotic liquid mass is frequently creamy yellow due to the presence of dead leukocytes and is commonly known as pus. Hypoxic infarcts in the brain presents as this type of necrosis, because the brain contains little connective tissue but high amounts of digestive enzymes and lipids, and cells therefore can be readily digested by their own enzymes. Gangrenous necrosis can be considered a type of coagulative necrosis that resembles mummified tissue. It is characteristic of ischemia of lower limb and the gastrointestinal tracts. Both dry gangrene and gas gangrene can lead to this type of necrosis. If superimposed infection of dead tissues occurs, then liquefactive necrosis ensues (wet gangrene).
In 2024, circana tracked approximately 11,000 unauthorized flavored disposable vape products in U.S. mainstream retail outlets, according to data reviewed by Reuters. In 2024, illegal sales of flavored disposable vapes reached about $2.4 billion and accounted for roughly 35% of all e-cigarette sales in mainstream retail outlets. According to data reviewed by Reuters, Circana estimated the total tracked vape market at $6.8 billion, excluding online and specialty store sales. A 2025 lawsuit by New York's attorney general cited testimony that one distributor sold more than $132 million worth of Elf Bar e-cigarettes in the prior year. Altria Group, one of the largest tobacco companies in the United States and the owner of Philip Morris USA, has significant investments in the domestic e-cigarette market. In January 2025, Altria said it was reassessing its 2028 "smoke-free" volume and revenue goals, citing competition from disposable vapes, and estimated that illicit disposable products represent 60% or more of the U.S. e-cigarette category despite lacking required authorizations. US authorities reported intensified enforcement actions against unauthorized e-cigarettes in 2025, including seizures of 4.7 million units valued at $86.5 million in a Chicago-based operation; US agencies also reported blocking more than 6 million unauthorized e-cigarettes worth over $120 million that year.
Sources: en.wikipedia.org
Reversed-phase high-performance liquid chromatography with ultraviolet detection at 214 nanometres is the usual approach. Peak area percentage provides a purity figure relative to other components in the sample. Mass spectrometry is then applied to confirm identity.
Aspartate can cyclise into a succinimide intermediate that later hydrolyses back as isoaspartate. Both forms share the same molecular mass, so mass spectrometry alone cannot tell them apart. This shapes how purity data should be interpreted.
Freeze-dried material is normally kept desiccated below minus twenty degrees Celsius and shielded from light. Solutions are prepared shortly before use and held cold. Repeated thawing is avoided because it accelerates aggregation and degradation.
Epitalon is a synthetic four-amino-acid peptide with the sequence alanine–glutamate–aspartate–glycine, also written AEDG. It was developed in Russian gerontology research and is studied for proposed effects on telomerase, melatonin regulation, and neuroendocrine function. It is not an approved pharmaceutical in the United States or the European Union.