The short version of Research chemical fits in a sentence. The long version — which is the one that helps — is below.
Reviewed 2025-09-08. Anything still debated is marked as such rather than presented as settled.
（TG:@pojiaai）Epitalon is a synthetic linear tetrapeptide with the sequence alanine-glutamate-aspartate-glycine, abbreviated AEDG. It emerged from work on epithalamin, a peptide fraction prepared from bovine pineal tissue, and was designed as a short, chemically defined analogue of that extract. Early publications came mainly from Russian laboratories studying pineal peptides and aging-related endpoints. The compound appears in the literature under several spellings, including epithalon and epithalone, which complicates systematic searching. Its small size makes solid-phase assembly and routine analytical characterization straightforward.
Chemically, the molecule consists of four amino acid residues joined by three peptide bonds, with a free N-terminal amino group and a free C-terminal carboxyl group. Its molecular formula is C14H22N4O9, and its monoisotopic mass is approximately 390 daltons. The acidic glutamate and aspartate side chains give the peptide a net negative charge near neutral pH, a property that shapes its chromatographic behaviour and solubility profile. No disulfide bridges or other post-translational modifications are present, so the primary sequence alone defines the structure.
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.
Identity and purity are checked by reversed-phase high-performance liquid chromatography, usually with ultraviolet detection near 214 nanometres, where the peptide bond absorbs. Mass spectrometry confirms the expected mass and reveals whether truncation products or adducts are present. Acid hydrolysis followed by amino acid analysis gives the residue ratio, which should approximate one alanine, one glutamate, one aspartate and one glycine. Counter-ions such as acetate or trifluoroacetate remain in the dried product and lower net peptide content, so a stated purity figure on a label does not by itself describe how much peptide a vial holds.
| Property | Value | Notes |
|---|---|---|
| Chemical class | Linear tetrapeptide | Four residues joined by three peptide bonds |
| Sequence | Ala-Glu-Asp-Gly | Commonly abbreviated AEDG |
| Molecular formula | C14H22N4O9 | Free acid form |
| Monoisotopic mass | Approximately 390 Da | Matches values reported from mass spectrometry |
| Net charge near neutral pH | Negative | Contributed by glutamate and aspartate side chains |
Epitalon is a synthetic tetrapeptide with the sequence alanine–glutamate–aspartate–glycine, commonly abbreviated AEDG. Its design traces to epithalamin, a peptide fraction prepared from bovine pineal gland extracts that researchers in Saint Petersburg began investigating in the 1970s. The compound has a molecular formula of C14H22N4O9 and a nominal molecular mass near 390 daltons. It holds no approved drug status in the United States or the European Union, and material sold under this name is generally offered as a research chemical rather than a finished pharmaceutical product.
Proposed mechanisms centre on cell-culture observations rather than a defined receptor interaction. Several reports describe increased expression of the telomerase catalytic subunit after exposure of cultured human cells, and the authors attributed the effect to short peptide fragments entering the nucleus and influencing gene transcription. No receptor for the tetrapeptide has been identified, and the free peptide is expected to be degraded rapidly by plasma peptidases. Whether any measurable fraction reaches intact tissues after administration remains an unresolved question rather than an established finding.
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.
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.
The great beneficiary was the PSOE, which led the campaign in favor of the "YES" vote and from then on became the hegemonic political force in Andalusia. The setback suffered by the UCD in Andalusia was added to the defeat in the municipal and regional elections in Catalonia and the Basque Country. To this was added the worsening of the economic situation as a result of the "second oil crisis" of 1979 (the number of unemployed exceeded one million), the resurgence of ETA's actions which in 1979 and 1980 marked the peak of its activity (174 dead in attacks perpetrated by ETA in those two years, a good part of them military), the growing citizen "disenchantment", etc. All this accentuated the political differences between the groups that made up UCD on various issues which opened a government crisis in mid-April 1980 that resulted in the formation of a new one whose "strong man" was the president's friend, Fernando Abril Martorell. Felipe González then presented a motion of censure against Suárez, which although he did not succeed in getting it through made him the highest-rated political leader in the polls, unseating Adolfo Suárez for the first time, and the PSOE became ahead of UCD in voting intentions. Suárez emerged very weakened from the Socialist motion of censure, which provoked a second crisis in his government in September 1980, which resulted in the departure of the former "strong man" Fernando Abril Martorell. However, the Christian-Democratic sector was not satisfied and started "a full-fledged rebellion".
Planar cell polarity (PCP) is a type of cell polarity in which the cells are oriented in a coordinated way across the plane of an epithelial tissue. The orientation is controlled by different cytoplasmic and transmembrane proteins concentrating on two opposite ends of the cells and forming dimers between neighboring cells. Common examples of PCP oriented tissue include animal fur, bird feathers, fish scales, wings of a fruit fly, and stereocilia in the inner ear. PCP also plays a major role in other biological processes, such as wound healing and embryonic development.
included bands from around the world in an attempt to promote international peace. The Scars covered apocalyptic poem "Your Attention Please" by Peter Porter, a radio broadcast announcing nuclear war. Probably the most famous of the 1980s songs against increased confrontation between the Soviets and the Americans was Nena's "99 Luftballons", which described the events – ostensibly starting with the innocent release of 99 (red) toy balloons – that could lead to a nuclear war. The Swedish band Imperiet's "Coca Cola Cowboys" is rock song about how the world is divided by two super powers that both claim to represent justice. Roman Palester, a classical music composer had his works banned and censored in Poland and the Soviet Union, as a result of his work for Radio Free Europe, even though he was thought to be Poland's greatest living composer at the time.
Sources: en.wikipedia.org
==== Silver ==== Silver ions have been shown to react with the thiol group in enzymes and inactivate them, leading to cell death. These ions can inhibit oxidative enzymes such as yeast alcohol dehydrogenase. Silver ions have also been shown to interact with DNA to enhance pyrimidine dimerization by the photodynamic reaction and possibly prevent DNA replication. The use of silver as an antimicrobial is well documented.
==== Risk of an oil spill ==== The FSO Safer, a floating oil storage and offloading tanker moored off Yemen’s Red Sea coast and holding around 1.1 million barrels of oil, has become a major humanitarian concern for the country. Since 2015, the vessel has not received proper maintenance, and experts have warned that corrosion or technical failure could lead to a large spill. Modelling exercises suggest that a serious spill could force the closure of major Red Sea ports such as Hudaydah and Salif, with the port of Aden possibly also affected in the Gulf of Aden. Such a scenario would cause an interruption of food assistance and a dramatically acute fuel shortage, among other consequences, and worsen the already severe humanitarian challenges the country is facing.
Michael Hurley (born 1 June 1990) is a former professional Australian rules footballer who played for the Essendon Football Club in the Australian Football League (AFL). He attended Viewbank College and was recruited by the Essendon Football Club with the fifth overall selection in the 2008 national draft.
Sources: en.wikipedia.org
In accordance with such findings, high-dose CPA shows equivalent effects on the prostate gland in men relative to high-dose diethylstilbestrol or buserelin, which both achieve castrate levels of testosterone. However, a lower dosage of 50 mg/day CPA has been found to produce a reduction in prostate volume in men with benign prostatic hyperplasia that is reportedly comparable to that observed with surgical or medical castration. In accordance, the dosage of CPA that achieves complete inhibition of the secretory function of the healthy prostate gland is around 50 to 100 mg/day, which is less than the dosage of 200 to 300 mg/day CPA that is used to treat prostate cancer. It has been said that in combined androgen blockade regimens with castration and CPA as the AR antagonist for prostate cancer, due to the marked reduction in androgen levels, lower dosages of CPA than those used as a monotherapy would seem to be equally effective. Relative to the 200 to 300 mg/day dosage of CPA used as a monotherapy in prostate cancer, the recommended dosage in combined androgen blockade is 100 to 200 mg/day. It has been stated that this dosage should be more than necessary to inhibit the effects of the remaining adrenal androgens in castrated men. Despite considerable suppression of testosterone levels, only a modest suppression of spermatogenesis typically occurs with 5 to 10 mg/day CPA, and azoospermia occurs only occasionally. Conversely, a combination of testosterone enanthate injections with 12.5 to 100 mg/day CPA results in azoospermia in most men.
=== Early studies === The first direct examination of the shroud by a scientific team was undertaken in 1969–1973 in order to advise on preservation of the shroud and determine specific testing methods. This led to the appointment of an 11-member Turin Commission to advise on the preservation of the relic and on specific testing. Five of the commission members were scientists, and preliminary studies of samples of the fabric were conducted in 1973. In 1976 the physicist John P. Jackson, the thermodynamicist Eric Jumper and the photographer William Mottern used image analysis technologies developed in aerospace science for analyzing the images of the Shroud. In 1977 these three scientists and over thirty other experts in various fields formed the Shroud of Turin Research Project. In 1978 this group, often called STURP, was given direct access to the Shroud. Joe Nickell of the Committee for Skeptical Inquiry has pointed out that "STURP's leaders served on the executive council of the Holy Shroud Guild, which is devoted to the "cause" of the reputed relic", a group whose motivation it was to campaign for the legitimacy of the Turin shroud. Paleontologist Steven Schafersman has described STURP as "an organization totally composed of believers in the authenticity of the Shroud", with the exception of a single agnostic being Walter McCrone. Also in 1978, independently from the STURP research, Giovanni Tamburelli obtained at CSELT a 3D-elaboration from the Shroud with higher resolution than Jumper and Mottern.
=== Pregnancy, lactation, and early childhood === The U.S. Recommended Dietary Allowance (RDA) for pregnancy is 2.6 micrograms per day (μg/d), for lactation 2.8 μg/d. Determination of these values was based on an RDA of 2.4 μg/d for non-pregnant women, plus what will be transferred to the fetus during pregnancy and what will be delivered in breast milk. However, looking at the same scientific evidence, the European Food Safety Authority (EFSA) sets adequate intake (AI) at 4.5 μg/d for pregnancy and 5.0 μg/d for lactation. Low maternal vitamin B12, defined as serum concentration less than 148 pmol/L, increases the risk of miscarriage, preterm birth and newborn low birth weight. During pregnancy the placenta concentrates B12, so that newborn infants have a higher serum concentration than their mothers. As it is recently absorbed vitamin content that more effectively reaches the placenta, the vitamin consumed by the mother-to-be is more important than that contained in her liver tissue. Women who consume little animal-sourced food, or who are vegetarian or vegan, are at higher risk of becoming vitamin depleted during pregnancy than those who consume more animal products. This depletion can lead to anemia, and also an increased risk that their breastfed infants become vitamin deficient. Vitamin B12 is not one of the supplements recommended by the World Health Organization for healthy women who are pregnant, however, vitamin B12 is often suggested during pregnancy in a multivitamin along with folic acid especially for pregnant mothers who follow a vegetarian or vegan diet.
Sources: en.wikipedia.org
It is a synthetic tetrapeptide with the sequence alanine-glutamate-aspartate-glycine, often abbreviated AEDG. The molecule is linear and contains no modified residues, so it is fully described by its sequence.
The compound came out of work on epithalamin, a peptide preparation derived from pineal tissue, conducted largely in Russian laboratories. Later studies in other countries examined it mainly in cell cultures and animal models.
The tetrapeptide sequence is a synthetic construct rather than a described circulating peptide. It was derived by analogy to peptide fractions obtained from tissue extracts, not isolated from blood or tissue as such.
The solid is kept cold, dry and dark, typically at minus twenty degrees Celsius, in a sealed container with desiccant. Dissolved material is kept refrigerated and used promptly. Freezing and thawing a solution repeatedly is avoided because it accelerates degradation.