counterion raises a handful of sensible questions. This page answers them in order, starting with the fundamentals and moving to applications.
This page was last updated on 2026-05-19 and is reviewed periodically as new material appears.
Epitalon is a synthetic tetrapeptide with the sequence alanine-glutamate-aspartate-glycine, commonly abbreviated AEDG. It was designed at the St. Petersburg Institute of Bioregulation and Gerontology as a short, chemically defined analogue of epithalamin, a fraction obtained from bovine pineal tissue. Small peptide bioregulators of this type formed a long-running line of work there from the 1980s onward. Because the molecule is produced by solid-phase synthesis rather than extraction, its composition is exact and its purity can be measured directly.
The most frequently cited proposed action is induction of telomerase, the enzyme that adds repeat sequences to chromosome ends. Cell-culture work from the originating group reported higher telomerase reverse transcriptase expression and measurable telomere elongation in human somatic cells after exposure. How a four-residue peptide would reach nuclear gene regulation is not established, and no cell-surface receptor or uptake route has been identified. Additional reports describe changes in melatonin secretion, antioxidant enzyme activity and lipid peroxidation in aged animals, but these findings remain mechanistically unconnected to the telomerase observation.
Solubility is high in water, phosphate-buffered saline and normal saline, a pattern that follows from the two acidic residues in the chain. The peptide dissolves poorly in non-polar solvents such as hexane or chloroform. Stock solutions are often prepared in water first and then diluted into the buffer of interest. Because the molecule is small and hydrophilic, filtration through a low-protein-binding membrane is usually straightforward, and visible particulates are uncommon in freshly made solutions.
Identity and purity are established with reversed-phase high-performance liquid chromatography and mass spectrometry. The chromatogram shows the main peak and any truncated or oxidised by-products, while the mass spectrum confirms the expected 390 dalton mass. Amino acid analysis can corroborate composition when a sample's origin is uncertain. Counterion content, particularly residual trifluoroacetate from purification, is frequently reported alongside purity because it shifts the net mass of the solid.
Reference material is normally supplied as a lyophilised powder in a sealed vial. Product literature typically recommends storage at minus twenty degrees Celsius or colder, protected from light and moisture. Freeze-thaw cycling is usually avoided because repeated condensation can introduce water into the vial. Working solutions are commonly prepared fresh, aliquoted, and kept cold for short periods rather than stored at ambient temperature. Labelling the date of opening helps track how long a vial has been in use.
| Property | Value | Notes |
|---|---|---|
| Molecular formula | C14H22N4O9 | Calculated from the four residues with three water losses |
| Molecular mass | About 390.35 g/mol | Monoisotopic mass near 390.14, used for mass-spectrometric identification |
| Peptide sequence | Ala-Glu-Asp-Gly | Single-letter form AEDG; no disulfide bonds or modified residues |
| Appearance | White to off-white solid | Supplied as a dried powder |
| Isoelectric point | Around 4 | Estimated from aspartate and glutamate side-chain pKa values |
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.
Peptides of this size are generally stable as dry solids but degrade in solution over time. The principal routes are hydrolysis of the peptide backbone and oxidation, with hydrolysis favoured by elevated temperature and extreme pH. Aqueous solutions held at room temperature can show measurable loss of purity within days, while frozen aliquots are considerably more durable. Because the sequence contains neither cysteine nor methionine, oxidation is less of a concern than for many other peptides, but pH control during handling still matters.
Typical storage for the lyophilized powder is −20 °C or lower, in a sealed container protected from light and moisture. Hygroscopic material should be allowed to equilibrate to room temperature before the vial is opened, which limits condensation on the contents. Working solutions are commonly divided into single-use aliquots and frozen to avoid repeated freeze-thaw cycles. Dilute solutions are more prone to adsorption onto plastic surfaces and to loss during filtration, so procedures that minimize transfers and use low-binding labware are preferable.
The proposed relationship between epitalon and pineal function is a central part of its background. Khavinson's group reported that short peptides corresponding to regions of larger pineal proteins could influence gene expression in cells. Epitalon was framed as a synthetic analogue of an active fragment rather than a direct isolation product. Whether the tetrapeptide reproduces the effects of the parent extract is an open question, because comparative studies are limited and the parent extract itself is not a single defined substance.
Interest in epitalon is usually discussed within the broader field of short peptide bioregulators, a category that includes other synthetic di-, tri-, and tetrapeptides studied by the same research group. These compounds share a common rationale: that small fragments of tissue-derived proteins can retain biological activity and can be produced reproducibly. The category as a whole remains outside mainstream pharmacological consensus, and epitalon specifically has a limited presence in independent, non-Russian research literature, which shapes how its evidence base is described.
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.
Purity assessment of peptide reagents normally relies on reversed-phase high-performance liquid chromatography. A gradient of acetonitrile in water with trifluoroacetic acid, paired with a C18 stationary phase, separates the target tetrapeptide from truncated sequences and deletion analogues. Detection at 214 nanometres exploits absorbance of the peptide backbone, since the molecule contains no aromatic residue. Results are expressed as a percentage of total peak area. Values above ninety-five percent are typical for research-grade material, although reporting conventions vary between suppliers.
14 September – UEFA warns the UK government that Britain could be prevented from hosting Euro 2028 over plans for a football regulator (outlined in the Football Governance Bill) because of concerns about "government interference" in the sport. 15 September – Columnists Jonathan Freedland, Hadley Freeman and David Aaronovitch resign from The Jewish Chronicle over a row concerning allegedly fabricated stories about Israeli military operations in Gaza. 16 September Huw Edwards, formerly the BBC's most senior news presenter, is given a six-month suspended jail sentence for child abuse image offences. He is placed on the sex offenders' register for seven years and is required to complete a rehabilitation programme. Junior doctors in England accept the government's offer of a 22% pay rise over two years, ending their long-running dispute. A study by Aston University Business School highlights the impact of Brexit red tape on trade between the UK and EU, which the study argues is getting worse. 17 September Glasgow is formally selected as the host city of the Commonwealth Games in 2026. A 12-year-old boy becomes the youngest person to be sentenced over the 2024 United Kingdom riots after receiving a 12-month referral at Liverpool Youth Court. A study suggests that UK goods exports to the EU were down 27% between 2021 and 2023, while imported goods were 32% lower over the same period than where they would have been had Brexit not happened. 18 September Train drivers accept a pay deal of 15% from the UK government, ending two years of strike action in England, Wales and Scotland.
Maddy Parsons is a British cell biologist who is a professor and Associate Dean for Impact & Innovation at King's College London. She is the Director of the Nikon Imaging Centre. Her research looks to understand the fundamental mechanisms that underpin cell adhesion and migration. She is Chair of the Medical Research Council Molecular & Cellular Medicine Board.
AOD9604 is an orally active, lipolytic 16-amino acid peptide fragment of human growth hormone and derivative of the C-terminal domain of human growth hormone (HGH). It consists of HGH residues 176–191, with a tyrosine in place of the phenylalanine at the N-terminal end. Initial human trials showed that it retains the lipolytic properties of human growth hormone without stimulating IGF-1 production. However, later studies failed to demonstrate a sufficient lipolytic effect. Its development was terminated in 2007. Despite its limited efficacy, AOD9604 is still banned in athletes and tested for in competition.
== Causes == Because of the small number of people diagnosed with hyperthymesia, relatively little is known about the processes governing this superior memory ability. However, more is beginning to be understood about this condition.
Sources: en.wikipedia.org
Debate about whether orgasm was even necessary for women began in the Victorian era, and Freud's 1905 theory about the immaturity of clitoral orgasms (see above) negatively affected women's sexuality throughout most of the 20th century. Toward the end of World War I, a maverick British MP named Noel Pemberton Billing published an article entitled "The Cult of the Clitoris", furthering his conspiracy theories and attacking the actress Maud Allan and Margot Asquith, wife of the prime minister. The accusations led to a sensational libel trial, which Billing eventually won; Philip Hoare reports that Billing argued that "as a medical term, 'clitoris' would only be known to the 'initiated', and was incapable of corrupting moral minds". Jodie Medd argues regarding "The Cult of the Clitoris" that "the female non-reproductive but desiring body [...] simultaneously demands and refuses interpretative attention, inciting scandal through its very resistance to representation". From the 18th to the 20th century, especially during the 20th, details of the clitoris from various genital diagrams presented in earlier centuries were omitted from later texts. The full extent of the clitoris was alluded to by Masters and Johnson in 1966, but in such a muddled fashion that the significance of their description became obscured; in 1981, the Federation of Feminist Women's Health Clinics (FFWHC) continued this process with anatomically precise illustrations identifying 18 structures of the clitoris.
A polycyclic aromatic hydrocarbon (PAH) is any member of a class of organic compounds that is composed of multiple fused aromatic rings. Most are produced by the incomplete combustion of organic matter—by engine exhaust fumes, tobacco, incinerators, in roasted meats and cereals, or when biomass burns at lower temperatures as in forest fires. The simplest representative is naphthalene, having two aromatic rings, and the three-ring compounds anthracene and phenanthrene. PAHs are uncharged, non-polar and planar. Many are colorless. Many of them are also found in fossil fuel deposits such as coal and in petroleum. Exposure to PAHs can lead to different types of cancer, fetal development complications, and cardiovascular issues. Polycyclic aromatic hydrocarbons are discussed as possible starting materials for abiotic syntheses of materials required by the earliest forms of life.
On 19 December, the National Guard stated that Syrian government forces in Rimat Hazim and Al-Mazra'a launched attacks towards Al-Majdal with drones and mortar fire, injuring two civilians, in addition to an infiltration by Syrian government forces on the northwest axis, resulting in four wounded. The National Guard accused Tareq al-Shoufi of "collaborating with Sharaa, and [he] went into hiding", while al-Hijri was "accused of kidnapping and his son of dealings with regional drug-smuggling networks, including Hezbollah." On 23 December, the National Guard stated that the Syrian government forces had “continued their attacks against al-Jabal and the surrounding areas”, using mortar fire, heavy machine guns, and drones. The city of Attil was attacked with mortar fire from Rimat Hazem and Tel Hadid, causing two deaths and eight injuries. There was also an attack on the civilian prison of Suwayda and transport directorate using heavy machine guns and mortar fire. On 24 December, clashes occurred between the National Guard and the Syrian government forces on the Ara-Khirbet Samar axis in the rural area of Suwayda and on the al-Majdal-al-Mazra'a axis, using 23mm heavy machine guns. That same day, the Royal Jordanian Air Force launched attacks on Suwayda that targeted “a series of factories and workshops that drug and arms traffickers use as bases to launch their illegal operations into Jordanian territory", It also attacked seven sites under the control of the National Guard, including a suspected weapons depot in Al Kafr, belonging to the Suwayda Military Council.
Samples are transported daily to the laboratory responsible for testing. In the United States and Canada, newborn screening is mandatory, with an option for parents to opt out of the screening in writing if they desire. In many regions, NBS is mandatory, with an option for parents to opt out in writing if they choose not to have their infant screened. In most of Europe, newborn screening is done with the consent of the parents. Proponents of mandatory screening claim that the test is for the benefit of the child, and that parents should not be able to opt out on their behalf. In regions that favour informed consent for the procedure, they report no increase in costs, no decrease in the number of children screened and no cases of included diseases in children who did not undergo screening.
Qingzhou (Chinese: 轻舟货运飞船; pinyin: Qīngzhōu huòyùn fēichuán) is a class of cargo spacecraft developed by CAS Space, a company founded by the Chinese Academy of Sciences. It is part of the China Manned Space Program's low-cost cargo transportation system designed to support the Tiangong space station. A prototype version of the Qingzhou spacecraft was successfully launched as the primary payload of the maiden flight of the Kinetica-2 (Lijian-2) rocket on 30 March 2026. The first production-standard spacecraft is expected to be ready for flight by late 2026.
Sources: en.wikipedia.org
The Japan Self-Defense Forces use two types of combat rations, Type I combat ration (Japanese: 戦闘糧食 I型) and Type II combat ration (Japanese: 戦闘糧食 II型). The older Type I ration consists almost entirely of canned foods weighing a total of 780 g per meal; a normal three-day ration has up to 36 cans weighing more than 7 kilograms. Eight menus are available, based around a 400 g can of rice and 2–3 smaller supplemental cans. Typical contents include: rice (white rice, sekihan, mixed rice with vegetables, or rice with mushrooms), a main meal can (chicken and vegetables, beef with vegetables, fish and vegetables, or hamburger patties), pickled vegetables (takuan or red cabbage) and sometimes a supplemental can (tuna in soy or beef in soy). In the latest type I combat rations, cans have been replaced by retort pouches. The newer, lighter Type II ration was originally intended to replace the Type I and consists of pre-cooked, ready-to-eat items in plastic-foil laminate retort pouches, packed in turn inside a drab green polyethylene meal bag. Each meal consists of two 200 g pouches of rice (white rice, rice with red beans, mixed rice with meat and vegetables, fried rice, curried rice pilaf, rice with green peas, or rice with wild herbs) plus 2–3 supplementary pouches. Main meal pouches contain: hamburger patties, frankfurters, beef curry, grilled chicken, Chinese meatballs, Sweet and Sour pork, grilled salmon, yakitori chicken, mackerel in ginger sauce, chicken and vegetables, and tuna.
{\displaystyle {\frac {\left({\sqrt {a}}-{\sqrt {b}}\right)^{2}+\left({\sqrt {b}}-{\sqrt {c}}\right)^{2}+\left({\sqrt {c}}-{\sqrt {a}}\right)^{2}}{\left({\sqrt {a}}+{\sqrt {b}}+{\sqrt {c}}\right)^{2}}}\leq {\frac {4}{9}}\left({\frac {R}{r}}-2\right).}
The diver needs to stay on the bottom to work some of the time, and may need to have neutral buoyancy some of the time. The diving suit is usually buoyant, so added weight is usually necessary. This can be provided in several ways. Unwanted positive buoyancy is dangerous to a diver who may need to spend significant time decompressing during the ascent, so the weights are usually attached securely to prevent accidental loss.
== Career in industry == Between the year 1947 and 1969, Beynon was Manager of Physics and Physical, Polymer and Analytical Chemistry at Imperial Chemical Industries. Between 1947 and 1950, Beynon constructed what was to become the first mass spectrometer designed to study organic compounds unrelated to petroleum. He subsequently collaborated with Metropolitan-Vickers to produce the MS8 mass spectrometer, a prototype of the Associated Electrical Industries (AEI) MS9 mass spectrometer. Beynon was made a senior research associate in 1964 which allowed him the opportunity to carry out his own research. He was a Boomer Memorial Fellow at the University of Minnesota in 1965.
Sources: en.wikipedia.org
No. Epithalamin is a peptide-containing extract of bovine pineal glands, while epitalon is a single synthetic tetrapeptide. The extract contains many peptides and other tissue components, so its composition varies between batches in ways that a synthesised sequence does not.
It is not recognised as an endogenous peptide hormone. The four-residue sequence can appear inside larger proteins and in digestive fragments of dietary protein, but no dedicated pathway producing it as a signalling molecule has been identified.
Several cell-culture reports describe increased telomerase activity after treatment, measured by enzyme assays or by transcript levels. Results differ between cell types and laboratories, and measured telomere lengthening has been reported in some studies but not in others, which leaves the physiological relevance open.
Sealed lyophilised powder is normally kept at minus twenty degrees Celsius or below, away from light and moisture. Vials are allowed to reach room temperature before opening to limit condensation. Repeated warming and cooling of the same vial is discouraged.