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Last reviewed on 2026-05-10. Where a claim depends on a specific study, the study is described rather than over-claimed.
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.
Identity and purity of epitalon samples are normally established by reversed-phase high-performance liquid chromatography with ultraviolet detection near 214 nanometres, combined with mass spectrometry. The mass spectrum confirms the expected molecular ion and can reveal truncated or oxidised by-products. Amino acid analysis after acid hydrolysis verifies that the four residues are present in the expected ratio. Certificates typically report a purity figure taken from chromatographic peak area, expressed as a percentage of total integrated signal.
Lyophilised epitalon is generally held at minus twenty degrees Celsius in a sealed container kept dry and dark. Cooler conditions are sometimes recommended for long-term archives. The solid takes up moisture readily enough that repeated opening of a vial introduces water, so dividing a batch into smaller portions before storage lowers degradation risk. Aqueous solutions are less durable than the dry powder and are usually prepared shortly before use, then kept cold and shielded from light to slow hydrolysis and oxidation.
| Property | Value | Notes |
|---|---|---|
| Molecular formula | C14H22N4O9 | Free acid form of the tetrapeptide |
| Molecular mass | About 390.35 Da | Calculated monoisotopic value |
| Appearance | White to off-white powder | Typical lyophilized presentation |
| Solubility | Soluble in water | Also dissolves in buffered saline |
| Storage temperature | Minus 20 degrees Celsius | Dry, dark conditions; avoid repeated thawing |
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.
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.
In addition to his third share of the 1962 Nobel Prize for Physiology or Medicine, he received many awards and honours, including the Royal and Copley medals of the Royal Society (1972 and 1975), and also the Order of Merit (on 27 November 1991); he refused an offer of a CBE in 1963, but was often referred to in error as 'Sir Francis Crick' and even on occasions as 'Lord Crick'. He was elected an EMBO Member in 1964. The award of Nobel Prizes to John Kendrew and Max Perutz, and to Crick, Watson, and Wilkins was satirised in a short sketch in the BBC TV programme That Was The Week That Was with the Nobel Prizes being referred to as 'The Alfred Nobel Peace Pools'. He was an elected member of the American Academy of Arts and Sciences (1962), the United States National Academy of Sciences (1969), and the American Philosophical Society (1972).
== Arrest, trial, and conviction == In July 2020, Mays was arrested and charged with the murders of eight individuals. The charges were later reduced to seven second-degree murders and one count of intent to commit murder involving the death of the 92-year-old United States Navy veteran Russell R. Posey Sr., who died two weeks after he had been injected with insulin. Prosecutors stated that there were approximately twenty suspicious deaths while Mays worked at the hospital, but charges were brought only for the cases that were believed to have sufficient evidence. On July 14, 2020, Mays pleaded guilty in the United States District Court for the Northern District of West Virginia in Clarksburg to seven counts of second-degree murder and one count of attempted murder. By pleading guilty to all of the charges, Mays waived the right to have the case presented to a grand jury. Mays wept openly in court and admitted that she had murdered the patients. Mays offered no motive but claimed to be taking medication for post-traumatic stress disorder (PTSD). She was held in custody at the West Virginia Regional Jail and Correctional Facility until her sentencing. An interview with Mays after her guilty plea was included in a report, released after the sentencing by the Department of Veterans Affairs' Office of Inspector General, that detailed deficiencies at the hospital.
IGN noted that stealth broke the AI, allowing traps to be triggered and leaving the assailants standing still, unable to locate a hidden player. GameSpy said that the Source engine was Bloodlines' greatest weakness; although the RPG aspects were the game's strong suit, Source's core features, such as first-person shooting, were where it stumbled. The combat was also criticized. Reviewers called it poor, clumsy and unsatisfactory, complaining that Bloodlines favors melee combat; firearms were weak, unwieldy and slow, even for characters specializing in guns. PC Zone, however, called the first-person shooting entertaining and challenging. Although melee combat was criticized as sluggish and difficult due to enemy attacks interrupting the player's, reviewers considered it overpowered; according to GameSpot, a boss character was killed with melee weapons on a first attempt after the repeated failure to do so with a gun. The New York Times found the unavoidable combat in the last part of the game to be so difficult that they had to cheat to succeed. Stealth was criticized, with IGN noting that even with low stealth skill it was possible to sneak around many enemies and feed from a guard without alerting another guard next to them. GameSpot opined that some of the best missions were stealth-based, as combat was more straightforward.
Sources: en.wikipedia.org
==== Cancer therapeutics ==== In 2022, over 1.9 million new cancer cases are projected in the U.S. alone. Nanogels are an attractive drug delivery solution for increasing both the efficacy of cancer therapeutics and their localization to cancer cells. Nanogels are currently being investigated for the treatment of different types of cancer, of which a few examples are listed here. In one study, chitosan-based nanogels loaded with doxorubicin, a chemotherapeutic, with a positive surface charge demonstrated a lower colorectal cancer cell viability compared to control groups and a similarly loaded nanogel with a negative surface charge. Another group conjugated folic acid to nanogels loaded with cisplatin or doxorubicin and delivered these therapeutics to ovarian cancer cells, which overexpress the folate receptor that binds with folic acid. These conjugated nanogels produced a significant decrease in tumor growth in a mouse model compared to vehicle controls and showed a site-specific delivery model for nanogels that may be effective for other types of cancer with upregulated folate receptors. Interestingly, gelatin-based nanogels loaded with cisplatin and conjugated to epidermal growth factor receptor (EGFR) ligands have been reported to successfully target lung cancer cells both in vitro and in vivo, with additional work confirming the effectiveness of these nanogels when transformed into aerosol particles.
== Development == Series writer Marc Laidlaw initially conceived of Black Mesa, and brainstormed numerous potential names before arriving on the final one, including "Black Butte Missile Base", "Diablo Plains", and "Diablo Mesa". In Half-Life 2: Raising the Bar, he professed that he was glad his final choice was Black Mesa Research Facility, rather than "Black Butte". Black Mesa's themes of science and horror were partially inspired by "The Borderland", an episode of The Outer Limits that focused on a team of scientists who manipulated magnetic fields to enter the fourth dimension. The monorail sequence that introduces the player to the Black Mesa facility was initially intended as a tech demo. Laidlaw stated that when a programmer implemented a new type of game object called "func_tracktrain", which allowed trains to branch onto different tracks, as well as bank and pivot into turns, he decided to incorporate a train into the game's story. The path of the monorail itself is made up of six different map files without individual loading screens, adding hallways as transition areas to give the illusion of level streaming. The disaster sequence in the test chamber was created in a single weekend by developers John Guthrie and Kelly Bailey, who worked for 48 hours straight without sleep, ultimately exciting everyone in the office when they discovered and played it the following Monday.
Telomerase, also called terminal transferase, is a ribonucleoprotein that adds a species-dependent telomere repeat sequence to the 3' end of telomeres. A telomere is a region of repetitive sequences at each end of the chromosomes of most eukaryotes. Telomeres protect the end of the chromosome from DNA damage or from fusion with neighbouring chromosomes. The fruit fly Drosophila melanogaster lacks telomerase, but instead uses retrotransposons to maintain telomeres. Telomerase is a reverse transcriptase enzyme that carries its own RNA molecule (e.g., with the sequence 3′-CCCAAUCCC-5′ in Trypanosoma brucei) which is used as a template when it elongates telomeres. Telomerase is active in gametes and most cancer cells, but is normally absent in most somatic cells.
Sources: en.wikipedia.org
=== General information === Colombia at Britannica.com Lamoureux, Andrew Jackson; Edmundson, George (1911). "Colombia" . Encyclopædia Britannica. Vol. 6 (11th ed.). pp. 700–713. Official investment portal Official Colombia Tourism Website (in Spanish) National Administrative Department of Statistics
=== (2) Separation and quantification methods === Separation methods are the first step to decomplexify the venom sample, with a common method being reverse‐phase high performance liquid chromatography (RP-HPLC). This method can be applied broadly to nearly all venoms as a crude fractionation method and to detect the peptide bonds found. A less common techniques like 1D/2D gel electrophoresis can also be used in cases of venoms containing heavy, complex peptides (Preferable >10KDa). This means in additions to RP-HPLC, Gel electrophoresis can help identify large molecules (such as enzymes) and to help refine venom prior to further analytical methods. Next, N-terminal sequencing is used to find the amino acid order of the fractionated proteins/peptides starting with the N-terminal end. Furthermore, SDS‐PAGE (Sodium dodecyl sulfate-polyacrylamide gel electrophoresis) can be performed on the isolated proteins from the RP-HPLC to identify proteins of interest before moving on to the identification stage.
== Precautions == Molybdenum dusts and fumes, generated by mining or metalworking, can be toxic, especially if ingested (including dust trapped in the sinuses and later swallowed). Low levels of prolonged exposure can cause irritation to the eyes and skin. Direct inhalation or ingestion of molybdenum and its oxides should be avoided. OSHA regulations specify the maximum permissible molybdenum exposure in an 8-hour day as 5 mg/m3. Chronic exposure to 60 to 600 mg/m3 can cause symptoms including fatigue, headaches and joint pains. At levels of 5000 mg/m3, molybdenum is immediately dangerous to life and health.
=== 21 December === The United States said it was aiming to provide military aid of $1.8 billion USD including the Patriot missile system. President Zelenskyy met US President Joe Biden during his visit and addressed a joint session of the US Congress after Speaker of the House Nancy Pelosi invited Zelenskyy. Citing the influx of conscripts from the 2022 Russian mobilization, Russian Minister of Defence Sergei Shoigu announced that the Moscow Military District was being re-established, alongside the Leningrad Military District. This was later confirmed in June 2023 by Deputy Chief of the General Staff Yevgeny Burdinsky.
Sources: en.wikipedia.org
Epitalon is a synthetic tetrapeptide built from four amino acids: alanine, glutamate, aspartate, and glycine. It is not extracted from a natural source but made in the laboratory by chemical synthesis. Its short length makes it relatively straightforward to produce at high purity.
No naturally occurring free form of the peptide has been described. The four-amino-acid sequence can appear as a fragment within larger proteins, but that is not the same as the intact compound being present as a circulating molecule. Materials used in research are synthetic.
Purity is usually checked by reverse-phase high-performance liquid chromatography, which separates the target peptide from related impurities. Mass spectrometry is commonly used alongside it to confirm molecular mass. Some suppliers also provide amino acid analysis for additional sequence confirmation.
The usual approach is reversed-phase HPLC with ultraviolet detection, reported as a percentage of total peak area. Mass spectrometry is used alongside chromatography to confirm identity rather than purity alone.