If you have been reading about AEDG and want a single page that covers the useful parts, this is it: definitions, context, how it is studied, and the questions that come up repeatedly.
Last reviewed on 2025-11-09. Where a claim depends on a specific study, the study is described rather than over-claimed.
Stability of the tetrapeptide follows ordinary peptide chemistry rather than any unusual structural feature. The aspartate-glycine pair is prone to aspartimide formation under mildly basic or neutral conditions, and deamidation can follow, altering both mass and chromatographic retention. Dry lyophilised powder kept at or below minus twenty degrees Celsius is the usual handling recommendation, with repeated freeze-thaw cycles avoided. Once dissolved in neutral aqueous buffer, degradation proceeds over days to weeks depending on pH and temperature, while acidic conditions generally slow the aspartimide route. A formal stability-indicating study has not been published in the indexed literature.
Because epitalon has no pharmacopoeial monograph, quality assessment depends on supplier documentation and independent testing. Certificates of analysis typically report a purity figure from a single chromatographic run, a measured mass and sometimes an appearance description, but methods and acceptance criteria are not harmonised across vendors. Third-party laboratories can repeat identity and purity measurements, and mismatches between labelled and measured peptide content have been described for research peptides generally. What constitutes adequate identity confirmation for a molecule of this size stays an open question, since mass agreement alone does not separate closely related sequences.
The parent extract epithalamin was characterised as a low-molecular-weight fraction of pineal tissue rather than a single defined chemical entity. Researchers fractionated it and tested successive fragments for activity, a screening approach typical of peptide discovery work in that era. Epitalon emerged from that process as one of the shorter sequences of interest. Because the original extract was never fully resolved into individual components, claims about which constituent drives a given effect rest on inference. This distinction matters when reading older reports that attribute extract observations to the tetrapeptide itself.
Epitalon is a synthetic tetrapeptide with the residue sequence alanine-glutamate-aspartate-glycine, commonly abbreviated AEDG. Its monoisotopic mass is approximately 390.35 daltons, and it is usually supplied as a lyophilised trifluoroacetate or acetate salt. The compound was derived from a pineal gland extract called epithalamin, a heterogeneous preparation investigated in the former Soviet Union. Researchers associated with the Saint Petersburg Institute of Bioregulation and Gerontology described the tetrapeptide as a constituent fragment of that extract. Commercial material is offered as a laboratory reagent rather than as a finished pharmaceutical product.
Literature searches for this compound must account for several spelling variants. Indexing databases contain epitalon, epithalon, epithalone, and AEDG, and relevant records are scattered across Russian-language and English-language journals that do not consistently cross-cite. Early publications describe the parent extract as a mixture of many peptides, whereas later work addresses the single synthetic tetrapeptide. That shift in nomenclature complicates comparison between studies, because extract data and tetrapeptide data are sometimes cited interchangeably. A search strategy omitting the alternate spellings will return an incomplete set of references.
| Property | Value | Notes |
|---|---|---|
| Analytical method | Reversed-phase HPLC | Purity determination, typically 214 nm |
| Mass confirmation | ESI or MALDI mass spectrometry | Compared with mass near 390 Da |
| Common synonyms | Epitalon, epithalon, AEDG | Naming differs between suppliers |
| Storage temperature | −20 °C or lower | Lyophilised powder, kept desiccated |
| Solution stability | Limited in neutral aqueous buffer | Aspartimide and hydrolysis pathways |
Identity and purity are usually assessed by reversed-phase high-performance liquid chromatography with ultraviolet detection, frequently near 214 nanometers where the peptide bond absorbs. Mass spectrometry, most often with electrospray ionization, confirms the observed molecular mass and helps separate the intact peptide from truncated or modified forms. Amino acid analysis or tandem mass spectrometry can establish residue order. Purity is commonly quoted as an area percentage, yet such values are method-dependent, and comparisons between laboratories require matching column, gradient and detection wavelength.
Laboratory handling begins with dissolution of the lyophilized powder in water or a suitable aqueous buffer. The dry solid is the more stable form, so stock solutions are generally prepared only when required and kept cold afterwards. Repeated freezing and thawing of a solution is avoided because it encourages aggregation and gradual loss of the intact chain. Diluents and containers are selected to limit adsorption of a short peptide onto plastic surfaces and to reduce microbial growth in aqueous preparations.
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.
Mahathir's political views have shifted during his lengthy career. During the 1980s and 1990s, he was a supporter of third-worldism, while during other periods he has been a proponent of "Asian values" and globalisation. A Muslim thinker, he holds Islamic political views. In 2002, he characterised himself as an Islamic fundamentalist. Mahathir is generally respected in developing and Islamic countries, particularly due to his oversight of Malaysia's economic growth and his support of liberal Muslim values. Mahathir has been described as a proponent of Malay nationalism. In The Malay Dilemma, he argued that the Malay race had been marginalised, and voiced his support for affirmative action policies for them. Upon his first resignation, he expressed his disappointment at the progress made towards his "principle task" of supporting the Malay race. In 2021, Mahathir said he did not believe in Ketuanan Melayu, calling it a "fantasy", and said instead that he believed in the concept of "Bangsa Malaysia". He has been described as anti-royalist by the left-wing French newspaper Libération, owing to his efforts to oppose immunity for members of Malaysia's monarchies. Mahathir is a vocal critic of neoliberalism and the Western world. In 2011, Mahathir suggested that the September 11 attacks might have been staged by the United States government. Mahathir condemned the Universal Declaration of Human Rights in 1997, suggesting it be revised to place greater importance on economic growth over civil liberties.
traveller's joy, a name invented for the sole British native, C. vitalba, by the herbalist John Gerard (1545–1612); virgin's bower for C. terniflora, C. virginiana, and C. viticella; old man's beard, applied to several with prominent seedheads; leather flower for those with fleshy petals; or vase vine for the North American Clematis viorna.
Occasionally, Journal Citation Reports assigns an impact factor to new journals with less than two years of indexing, based on partial citation data. The calculation always uses two complete and known years of item counts, but for new titles one of the known counts is zero. Annuals and other irregular publications sometimes publish no items in a particular year, affecting the count. The impact factor relates to a specific time period; it is possible to calculate it for any desired period. For example, the JCR also includes a five-year impact factor, which is calculated by dividing the number of citations to the journal in a given year by the number of articles published in that journal in the previous five years.
=== Sublingual administration === Estradiol tablets can be taken sublingually instead of orally. Non-micronized estradiol tablets in doses of 0.125, 0.25, and 1 mg were previously marketed for use by sublingual administration under brand names such as Diogynets, Estradiol Membrettes, and Dimenformon in the 1950s. Non-micronized estradiol has poor water solubility, but micronized estradiol is rapidly absorbed by the sublingual route. All oral estradiol tablets are micronized, as this improves the efficiency of estradiol absorption in the gastrointestinal tract. Likewise, all oral estradiol valerate tablets seem to be micronized. The sublingual route is, in actuality, probably a combination of sublingual and oral delivery of estradiol due to incidental swallowing of some of the estradiol. The absorption of sublingual estradiol can be attributed to the rich vascularization under the tongue. With administration of an oral estradiol tablet sublingually, complete dissolution of the tablet occurs within a few minutes and circulating levels of estradiol begin to rise within 5 minutes. Maximal levels of estradiol occur after 30 to 60 minutes of administration. After this, estradiol levels drop steeply within 4 hours, and this is followed by a more gradual decline in levels of estradiol and a return to baseline concentrations by 24 hours. The rapid rise and steep fall of estradiol levels with sublingual administration of estradiol is analogous to the case of intravenous injection and intranasal administration of the hormone.
C12H22O11 + H2O → 2 C6H12O6 Heterolactic fermentation is in a sense intermediate between lactic acid fermentation and other types, e.g. alcoholic fermentation. Reasons to go further and convert lactic acid into something else include:
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=== Heat of solution === Erythritol has a strong cooling effect (endothermic, or positive heat of solution) when it dissolves in water, which is often compared with the cooling effect of mint flavors. The cooling effect is present only when erythritol is not already dissolved in water, a situation that might be experienced in an erythritol-sweetened frosting, chocolate bar, chewing gum, or hard candy. The cooling effect of erythritol is very similar to that of xylitol and among the strongest cooling effects of all sugar alcohols. Erythritol has a pKa of 13.903 at 18 °C.
== Early years == Of German descent, Christopher Richard Stein was born on 4 January 1947 in Churchill, Oxfordshire, to Eric Stein (1908–1965) and Dorothy Gertrude née Jackson (1909–1999). He was born and brought up on a farm. Stein was educated at Wells Court, a preparatory school just outside Tewkesbury, then Wells House, the Court's bigger sister-school at Malvern Wells, and then Uppingham School. He took A-levels in English, history and geography, but failed all of them. He moved to a cram school in Brighton, gaining E grades in English and history. Stein partially completed a hotel management traineeship with British Transport Hotels at its Great Western Royal Hotel in Paddington. He worked there as a chef for six months. Distraught by his father's suicide, at age 19 he went to Australia, where he worked as a labourer in an abattoir and as a clerk in a naval dockyard. To "take some time out" he travelled to New Zealand, where he picked asparagus, and Mexico. His 21st birthday was spent in Kaikōura, New Zealand, where he ate a rock lobster and slept under a bridge. Being on his own, he read widely, reflected on his attitude to education, and applied successfully to New College, Oxford, where he earned an English degree in 1971. Shortly after that, he moved to Padstow.
He then reactivated Rhyme Syndicate and formed a deal with Priority Records for distribution. Priority released Home Invasion in the spring of 1993. The album peaked at No. 9 on Billboard magazine's Top R&B/Hip-Hop Albums and at No. 14 on the Billboard 200, spawning several singles including "Gotta Lotta Love", "I Ain't New Ta This" and "99 Problems" – which would later inspire Jay-Z to record a version with new lyrics in 2003. In 2003 he released the single "Beat of Life" with Sandra Nasić, Trigga tha Gambler and DJ Tomekk and placed in the German charts. Ice-T had also collaborated with certain other heavy metal bands during this time period. For the film Judgment Night, he did a duet with Slayer on the track "Disorder". In 1995, Ice-T made a guest performance on Forbidden by Black Sabbath. Another album of his, VI – Return of the Real, was released in 1996, followed by The Seventh Deadly Sin in 1999. His first rap album since 1999, Gangsta Rap, was released on October 31, 2006. The album's cover, which "shows [Ice-T] lying on his back in bed with his ravishing wife's ample posterior in full view and one of her legs coyly draped over his private parts", was considered to be too suggestive for most retailers, many of which were reluctant to stock the album. Some reviews of the album were unenthusiastic, as many had hoped for a return to the political raps of Ice-T's most successful albums.
Malaysia is a federal constitutional elective monarchy and the only federal country in Southeast Asia. The system of government is closely modelled on the Westminster parliamentary system, a legacy of British rule. The head of state is the King, whose official title is the Yang di-Pertuan Agong. The King is elected to a five-year term by and from among the nine hereditary rulers of the Malay states. The other four states, which have titular Governors, do not participate in the selection. By informal agreement the position is rotated among the nine, and has been held by Ibrahim Iskandar of Johor since 31 January 2024. The King's role has been largely ceremonial since changes to the constitution in 1994, picking ministers and members of the upper house. Legislative power is divided between federal and state legislatures. The bicameral federal parliament consists of the lower house, the House of Representatives and the upper house, the Senate. The 222-member House of Representatives is elected for a maximum term of five years from single-member constituencies. All 70 senators sit for three-year terms; 26 are elected by the 13 state assemblies, and the remaining 44 are appointed by the King upon the Prime Minister's recommendation. The parliament follows a multi-party system and the government is elected through a first-past-the-post system. Parliamentary elections are held at least once every five years.
== Occurrence == Quercetin is a flavonoid widely distributed in nature. The name has been used since 1857, and is derived from quercetum (oak forest), after the oak genus Quercus. It is a naturally occurring polar auxin transport inhibitor. Quercetin is one of the most abundant dietary flavonoids, with an average daily consumption of 25–50 mg.
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coenocyte A multinucleate mass of cytoplasm bounded by a cell wall and resulting from continuous cytoplasmic growth and repeated nuclear division without cytokinesis, found in some species of algae and fungi, e.g. Vaucheria and Physarum.
Another electrophysiological measurement that can be made is fusion event duration in a nystatin-ergosterol based system. Fusions are measured while the voltage is held constant, and is characterized by a spike in the current that then returns to the baseline current as the nystatin channels close. When present in smaller concentrations, nystatin momentarily forms pores that allows a vesicle fusion to occur more easily; that fusion then interrupts the pore stability and the nystatin and ergosterol disperse from each other. Conversely, researchers have found that the half-life of these nystatin pores increase with an increased dosage level of nystatin to the membrane systems. This indicates a lower energy of both the lipid membrane and the ionophores when there is a higher concentration of nystatin.
Early in the 20th century, Dentistry shifted from treatment based therapy to prevention and as such, dentures that were in line with good health became more favourable. Having a clear occupation for dentures alone became a requirement.
Benzethidine is a 4-phenylpiperidine derivative that is related to the clinically used opioid analgesic drug pethidine (meperidine, or Demerol). Benzethidine is not currently used in medicine and is a Class A/Schedule I drug which is controlled under UN drug conventions. It has similar effects to other opioid derivatives, such as analgesia, sedation, nausea and respiratory depression. In the United States, the drug is a Schedule I Narcotic Controlled Substance with a DEA ACSCN of 9606 and 2014 annual aggregate manufacturing quota of nil. The most common salt in use is the hydrochloride, free base conversion ratio of 0.910.
== Remote monitoring and control == Modern refrigerated containers are often equipped with a telematic control unit and a GPS tracking unit that enables remote monitoring of the container's parameters as part of a fleet telematics system. This integration is part of the fleet digitalization of the logistics industry, making the container an element of a larger Vehicle tracking system. The system allows a fleet management operator to track the container's location and monitor internal parameters such as temperature, humidity, and door status. This continuous stream of telemetry provides a complete track and trace record of the container's temperature throughout its journey, which helps ensure the integrity of the cold chain. If the temperature deviates from the set point, the system can send an automatic alert to the operator, allowing for immediate intervention. These systems also allow for remote control, enabling an operator to change the temperature settings or turn the refrigeration unit on or off from a central software platform.
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The molecule lacks aromatic residues, so it absorbs weakly near 280 nanometres, the wavelength applied to many other peptides. The peptide bond absorbs strongly below 220 nanometres, making 214 nanometres a practical compromise. Gradient methods must therefore use mobile phases with low ultraviolet absorbance to keep the baseline clean.
Neutral and slightly basic aqueous conditions promote aspartimide formation at the aspartate-glycine step, often followed by deamidation. Elevated temperature and repeated freeze-thaw cycles accelerate the loss. Acidic solutions and dry lyophilised powder are comparatively stable over short periods.
No monograph exists in the United States Pharmacopeia or the European Pharmacopoeia, and no widely distributed certified reference standard is available. Purity and identity therefore rest on supplier methods that are not harmonised. This absence is the main reason reported purities are difficult to compare between sources.
It is based on epithalamin, a peptide-rich preparation obtained from pineal gland tissue and studied in the former Soviet Union. Researchers later identified the tetrapeptide AEDG as a constituent fragment of that material. Modern supplies are produced by chemical synthesis rather than tissue extraction.