A practical reference on research chemical: what it is, how it behaves, what the literature reports, and where the honest uncertainties sit.
Reviewed 2026-08-01. Anything still debated is marked as such rather than presented as settled.
Stability depends strongly on pH, temperature and the presence of oxygen and trace metals. Cleavage of the backbone proceeds faster under neutral to alkaline conditions, whereas acidic solutions tend to slow that reaction. The aspartate and glutamate side chains can undergo deamidation or imide formation over time, generating closely related impurities. Published stability data specific to epitalon are sparse, so the usable life of a given solution is best regarded as an open question that depends on buffer composition, concentration and storage temperature.
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.
Epitalon is the common name for a synthetic tetrapeptide with the sequence alanine-glutamate-aspartate-glycine, usually abbreviated AEDG. All four residues are proteinogenic amino acids, and the free peptide has a calculated mass near 390 grams per mole. Because the chain is short and carries no modifications, it is assembled readily by solid-phase synthesis and is distributed mainly as a freeze-dried solid for laboratory work. Catalogue listings use the spellings epitalon, epithalone, and simply AEDG, and the three refer to the same sequence.
The compound is generally presented as a synthetic fragment of epithalamin, a pineal gland extract investigated in the former Soviet Union from the 1970s onward. Vladimir Khavinson and colleagues in Saint Petersburg developed short peptides modelled on such extracts, and epitalon became the most widely cited of those sequences. Most primary reports appeared in Russian-language journals or in proceedings with limited international circulation. Independent replication in laboratories outside that network remains sparse, and much repeated secondary material traces back to a small number of originating groups.
| Property | Value | Notes |
|---|---|---|
| Storage temperature, dry powder | -20 degrees Celsius or lower | Sealed, dark, low humidity |
| Storage temperature, solution | 2 to 8 degrees Celsius | Short-term use expected |
| Primary purity method | Reversed-phase HPLC | Ultraviolet detection near 214 nm |
| Identity confirmation | Electrospray mass spectrometry | Compared with calculated mass |
| Typical purity specification | Area percent of 95 or higher | Depends on column and gradient |
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.
Identity confirmation uses mass spectrometry, usually electrospray ionisation in positive mode or matrix-assisted laser desorption. The protonated free peptide produces a signal near three hundred and ninety-one daltons, while salt adducts shift that value slightly. Tandem mass spectrometry or amino acid analysis supplies sequence-level confirmation, which a single mass measurement cannot. Peptides containing aspartate can cyclise into succinimide intermediates that hydrolyse to isoaspartate isomers of identical mass. Because those isomers are difficult to separate chromatographically, identity and purity results carry more weight when interpreted together.
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.
Storage recommendations center on limiting moisture, heat, and light. The dry powder is generally kept at minus 20 degrees Celsius, and some suppliers recommend minus 80 degrees for long-term archival. Once dissolved, solutions are usually aliquoted and frozen to avoid repeated freeze-thaw cycles, which can promote aggregation or degradation. Aqueous stability depends on pH and concentration, and buffered saline is often preferred over plain water for biological work. Stability data specific to epitalon remain limited, so general peptide-handling practices are applied by analogy rather than from product-specific validation.
Epitalon is a synthetic tetrapeptide with the sequence alanine-glutamate-aspartate-glycine, abbreviated AEDG. Its molecular formula is C14H22N4O9 and its calculated monoisotopic mass is approximately 390.35 daltons. The compound does not occur naturally as a free peptide; it is produced by solid-phase peptide synthesis. Because it contains two acidic residues and no basic residues, the neutral form carries a net negative charge at physiological pH. This charge profile influences how the peptide behaves in solution and during chromatographic analysis.
Laboratory-grade epitalon is typically supplied as a lyophilized powder. Purity is commonly assessed with reverse-phase high-performance liquid chromatography, often paired with mass spectrometry to confirm molecular identity. Amino acid analysis and peptide mapping can provide additional confirmation of sequence. Certificates of analysis for research materials frequently report purity above 95 percent, although the methods behind such figures vary between suppliers. The absence of a pharmacopeial monograph means that no single standardized assay defines the compound, so reported results depend on the analytical protocol chosen.
Analytical characterization of epitalon relies on standard peptide methods. Reverse-phase high-performance liquid chromatography is used to assess purity, and mass spectrometry confirms identity by checking the observed mass against the expected value near 390 daltons. Amino acid analysis can verify composition. Because the peptide is short and hydrophilic, it elutes early on many reverse-phase columns, so method development often requires ion-pairing reagents to achieve adequate retention and resolution from related impurities.
Storage and handling follow conventional peptide practice. Lyophilized epitalon is typically kept refrigerated or frozen, protected from moisture and light, and allowed to equilibrate to room temperature before opening to avoid condensation. Once dissolved, aqueous solutions are usually stored cold and used within a short period, since dilute peptide solutions can support microbial growth and may slowly degrade. The absence of cysteine and methionine reduces, but does not eliminate, oxidation concerns during long-term storage.
== Reception == Counter-Strike is considered one of the most influential first person shooters in history. The series has a large competitive community and has become synonymous with first person shooters. As of August 2011, the Counter-Strike franchise has sold over 25 million units. Because of its popularity, Counter-Strike has attracted considerable academic attention. Researchers have used data from Counter-Strike, among others, to examine the mood of players, performance of obese players, and performance changes since the start of the Russian invasion in Ukraine.
=== Available biosimilars === As of 2025, there are three commercially available biosimilar insulins. They are insulin glargine-yfgn, insulin glargine-aglr, and insulin aspart-szjj. Insulin glargine-yfgn is marketed under the name Semglee, and received FDA approval in July 2021, but development began before that. The approval was granted to Mylan, which was merged with another company into Viatris in 2020. The second approved biosimilar insulin, insulin glargine-aglr, was approved by the FDA in December 2021 to be produced by Lilly under the name Rezvoglar. In February 2025, the FDA approved the very first short-acting biosimilar insulin, insulin aspart szjj. It is manufactured by Viatris and sold under the name Merilog. It is of note that although the name of insulin lispro-aabc, which is marketed as Lyumjev by Lilly, is similar to the names of biosimilars, it is not a biosimilar insulin. Insulin lispro-aabc is simply a faster formulation of insulin lispro.
In March 2009, Komsomolskaya Pravda reported that on the morning of 8 August 2008, at around 6:00 AM tank shell hit the observer post and wounded lieutenant Oleg Galavanov. Galavanov had returned from Russia to Tskhinvali in 2007 and worked in the Ministry of Defense and Emergency Situations of South Ossetia. He served as artillery spotter. In August 2009, South Ossetian news agency RES reported that 32-year old Oleg Galavanov had been promoted to the rank of lieutenant in 2007. In October 2008, Konstantin Timerman, the commander of the Russian peacekeeping battalion, said in an interview with Izvestia that on the morning of 8 August the Russians opened fire in response only after the Georgians had opened fire on the observer post in the southern part of Tskhinvali. If we take into consideration that Golovanov is listed as an employee of the South Ossetian Defense Ministry, it turns out that the Georgian fire against the Russian peacekeeping base was provoked by the Ossetian fire from the roof. In 2009, the Russian authorities told the Tagliavini commission that the Russian peacekeepers suffered the first casualties at 6:35 am on 8 August, when the Georgian tank was firing on the observer post on the roof of the peacekeepers' base. As a result one soldier of the battalion died, another one was wounded and the part of the building was destroyed. By noon two peacekeepers had died and five were wounded. Georgia said that it only targeted Russian peacekeepers in self-defence, after coming under fire from them.
Sources: en.wikipedia.org
=== August === 1 August Nationwide reports that house prices fell by 3.8% in July, the sharpest decline since July 2009. The UK's first permanent drone delivery service begins, with Royal Mail and Skyports establishing a daily inter-island mail distribution between three islands on Orkney. Changes on excise duty for alcohol come into force, with the tax levied depending on a drink's strength. Former SNP MP Margaret Ferrier loses her seat, following a successful recall petition, triggering a by-election. 2 August – COVID-19 in the UK: The UK Health Security Agency reports the spread of a new variant known as EG.5.1. 3 August The National Risk Register publishes its latest report on future threats facing the UK. It puts the chance of another pandemic at between 5% and 25%. Other risks include extreme weather caused by worsening climate change, advances in artificial intelligence (AI) systems, terrorism such as cyberattacks on infrastructure, and the assassination of public figures. Greenpeace activists climb onto the roof of Rishi Sunak's North Yorkshire home, unfurling sheets of black fabric, in protest at his recent decision to expand oil and gas production in the North Sea. The Bank of England raises its baseline interest rate from 5% to 5.25%, the 14th consecutive increase and the highest level since April 2008. The Bank also predicts inflation to fall below 5% in the final quarter of 2023. Brexit: Checks on fresh food from the EU are delayed for a fifth time, amid concerns over red tape.
1905: American geneticist Nettie Stevens discovered sex chromosomes. 1906: Following the San Francisco earthquake, American botanist and curator Alice Eastwood rescued almost 1500 rare plant specimens from the burning California Academy of Sciences building. Her curation system of keeping type specimens separate from other collections – unconventional at the time – allowed her to quickly find and retrieve the specimens. 1906: Russian chemist Irma Goldberg published a paper on two newly discovered chemical reactions involving the presence of copper and the creation of a nitrogen-carbon bond to an aromatic halide. These reactions were subsequently named the Goldberg reaction and the Jourdan-Ullman-Goldberg reaction. 1906: English physicist, mathematician and engineer Hertha Ayrton became the first female recipient of the Hughes Medal from the Royal Society of London. She received the award for her experimental research on electric arcs and sand ripples. 1906: After her death, English lepidopterist Emma Hutchinson's collection of 20,000 butterflies and moths was donated to the London Natural History Museum. She had published little during her lifetime, and was barred from joining local scientific societies due to her gender, but was honoured for her work when a variant form of the comma butterfly was named hutchinsoni. 1907: Swedish-Norwegian physicist and nutritionist Signe Schmidt-Nielsen became one of the first women in Sweden to receive a doctoral degree. She was also the first woman to become a member of the Royal Norwegian Society of Sciences and Letters.
==== Taiwan ==== In Taiwanese cuisine, they are called dōngfěn (Chinese: 冬粉; lit. 'winter flour'). They are a versatile ingredient used in soups, stir-fries, hot pots, and street food. A popular Taiwanese dish featuring glass noodles is bah-oân (肉圓), a translucent, doughy snack filled with meat and vegetables, often including glass noodles in the filling for added texture. Glass noodles are also a staple in Taiwanese-style lu wei (滷味), a braised food stall dish where various ingredients, including glass noodles, are simmered in a spiced soy-based broth and served hot or cold. In Hakka cuisine, a traditional preparation called kè jīa fěn sī (客家粉絲) involves stir-frying glass noodles with dried shrimp, mushrooms, pork, and preserved vegetables. Glass noodles are also often included in festive banquet dishes, such as steamed seafood casseroles and Buddha Jumps Over the Wall (佛跳牆), where they absorb rich flavours from broths and other ingredients. Taiwanese hot pots (火鍋) frequently include glass noodles as an essential add-in that soaks up the broth while maintaining a chewy texture, especially in spicy or medicinal broths popular in winter.
Night sweats, also known as nocturnal hyperhidrosis, is the occurrence of excessive sweating during sleep. The person may or may not also perspire excessively while awake. One of the most common causes of night sweats in women over 40 is the hormonal changes related to menopause and perimenopause. This is a very common occurrence during the menopausal transition years. While night sweats might be relatively harmless, it can also be a sign of a serious underlying disease. It is important to distinguish night sweats due to medical causes from those that occur simply because the sleep environment is too warm, either because the bedroom is unusually hot or because there are too many covers on the bed. Night sweats caused by a medical condition or infection can be described as "severe hot flashes occurring at night that can drench sleepwear and sheets, which are not related to the environment". Some of the underlying medical conditions and infections that cause these severe night sweats can be life-threatening and should promptly be investigated by a medical practitioner.
Sources: en.wikipedia.org
== History == Prior to 1960, the thymus gland, which lies in the cervical thoracic area, was thought to be of little importance. In adult animals, the thymus is almost non-existent because it atrophies as animals reach adulthood. It was observed, however, that when pre-adolescent animals are thymectomized, they experience a variety of maladies including increased incidence of infection, failure to grow, neuromuscular disorders, cancer, etc., collectively known as “wasting disease”. The greater susceptibility to infection was shown to be directly attributable to a dramatic decrease in peripheral blood lymphocytes in thymectomized animals. By 1964 it had been demonstrated that regulatory factors extracted from the thymus gland could prevent many of the manifestations of wasting disease. This suggested that the thymus produces substances important in the development of immunity. It was not until 1971 that it was discovered that thymus-derived lymphocytes (T-cells) were important regulators of bone-marrow-derived antibody-producing lymphocytes (B-cells). After the discovery that the thymus was producing profound regulatory factors, several groups of scientists began trying to extract and purify this factor from thymus glands in much the same manner that insulin was prepared from the pancreas for therapeutic use in diabetes. The difficulty was that the thymus is a very small gland and produces very small quantities of the factor. Thus, purification techniques did not allow appropriate pure fractions to be produced in sufficient quantities.
=== Diarrhea === Diarrhea is more common and sometimes more severe with flutamide than with other NSAAs. In a comparative trial of combined androgen blockade for prostate cancer, the rate of diarrhea was 26% for flutamide and 12% for bicalutamide. Moreover, 6% of flutamide-treated patients discontinued the medication due to diarrhea, whereas only 0.5% of bicalutamide-treated patients did so. In the case of antiandrogen monotherapy for prostate cancer, the rates of diarrhea are 5 to 20% for flutamide, 2 to 5% for bicalutamide, and 2 to 4% for nilutamide. In contrast to diarrhea, the rates of nausea and vomiting are similar among the three medications.
== History == The first recombinant plant-derived protein (PDP) was human serum albumin, initially produced in 1990 in transgenic tobacco and potato plants. Open field growing trials of these crops began in the United States in 1992 and have taken place every year since. While the United States Department of Agriculture has approved planting of pharma crops in every state, most testing has taken place in Hawaii, Nebraska, Iowa, and Wisconsin. In the early 2000s, the pharming industry was robust. Proof of concept has been established for the production of many therapeutic proteins, including antibodies, blood products, cytokines, growth factors, hormones, recombinant enzymes and human and veterinary vaccines. By 2003 several PDP products for the treatment of human diseases were under development by nearly 200 biotech companies, including recombinant gastric lipase for the treatment of cystic fibrosis, and antibodies for the prevention of dental caries and the treatment of non-Hodgkin's lymphoma. However, in late 2002, just as ProdiGene was ramping up production of trypsin for commercial launch it was discovered that volunteer plants (left over from the prior harvest) of one of their GM corn products were harvested with the conventional soybean crop later planted in that field. ProdiGene was fined $250,000 and ordered by the USDA to pay over $3 million in cleanup costs. This raised a furor and set the pharming field back, dramatically. Many companies went bankrupt as companies faced difficulties getting permits for field trials and investors fled.
Germany's military, the Bundeswehr (Federal Defence), is organised into the Heer (Army and special forces KSK), Marine (Navy), Luftwaffe (Air Force) and Cyber- und Informationsraum (Cyber and Information Domain Service) branches. In absolute terms, German military spending in 2025 was the fourth-highest in the world. In response to the 2022 Russian invasion of Ukraine, Chancellor Olaf Scholz announced that German military expenditure would be increased past the NATO target of 2%, along with a one-time 2022 infusion of 100 billion euros, representing almost double the 53 billion euro military budget for 2021. In 2023, military spending according to NATO criteria amounted to $73.1 billion, or 1.64% of the country's GDP, well below the NATO target of 2%. In 2026, Germany reported an estimated spending of $147.002 billion to NATO, exceeding said target at 2.69% of GDP. As of May 2024, the Bundeswehr has a strength of 180,215 active soldiers and 80,761 civilians. Reservists are available to the armed forces and participate in defence exercises and deployments abroad. Until 2011, military service was compulsory for men at age 18, but this has been officially suspended and replaced with a voluntary service. Since 2001 women may serve in all functions of service without restriction. According to the Stockholm International Peace Research Institute, Germany was the fourth-largest exporter of major arms in the world between 2021 and 2025. In peacetime, the Bundeswehr is commanded by the Minister of Defence.
When most of the alar lobule tissue is missing, the nose collapses; the correction is with an ear concha cartilage-graft harvested from the antihelix, a donor site where the cartilage is most rigidly curved, thus is ideal for replacing an alar lobule. Nasal skin defects can be corrected with a medially based bilobed flap, which is emplaced to provide adequate skin coverage for wounds limited to the alar lobule. If the entire lobule is missing, it might be necessary to leave the second-lobe donor-site wound partially open; it will close at 2–4 weeks post-operative; afterwards, the scar can be revised. Nonetheless, the alternative surgical correction is a two-stage, superiorly based, nasolabial flap. If the alar lobule defect also comprehends the lateral wall of the nose, the defect can be closed either with a superiorly based nasolabial-flap or with a forehead flap. If the cheek skin is thin and atrophic, a nasolabial flap is the recommended reconstruction; otherwise, a forehead flap is recommended, because the thickness of forehead skin is a superior match for nasal skin and tissue. Mucosal lining defects of the alar lobule can be resurfaced with a bipedicled mucosal advancement-flap harvested from inside the lateral wall of the nose. Likewise, larger defects of the mucosa do require correction with an anteriorly based septal mucosal flap. III.
Sources: en.wikipedia.org
The dry powder is typically held at -20 degrees Celsius or lower, protected from light and moisture. Allowing a sealed vial to reach room temperature before opening reduces condensation on its contents. Conditions stated on a supplier certificate of analysis take precedence over general guidance.
Mass spectrometry supplies an observed molecular mass that is compared with the calculated value for the tetrapeptide. Reversed-phase chromatography then separates the main peak from related impurities. Neither technique alone establishes residue order, so sequence-level confirmation may call for tandem mass spectrometry or amino acid analysis.
No single published figure applies, because stability depends on pH, concentration, temperature and sterility. Cold storage slows hydrolysis without halting it, and microbial growth is a separate concern in non-sterile solutions. Most laboratories rely on their own analytical checks rather than a fixed expiry period.
It is a four-amino-acid peptide with the sequence alanine-glutamate-aspartate-glycine. The chain is unmodified and contains only standard proteinogenic residues, which makes it straightforward to produce by solid-phase synthesis and to characterise by standard peptide methods.