This is a working overview of lyophilisation, written for readers who want more than a one-paragraph summary but less than a textbook.
This page was last updated on 2026-06-11 and is reviewed periodically as new material appears.
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.
Verification of research-grade material involves comparing a supplier chromatogram against an in-house reference, checking the observed mass against the calculated value, and where possible confirming residue order by tandem mass spectrometry or enzymatic peptide mapping. Purity claims should be read alongside the method used to obtain them, because detection wavelength and integration settings alter the result. Batch-specific data, rather than a generic grade statement, is the informative part of a certificate.
The compound is described in the literature as a derivative of epithalamin, a preparation obtained from bovine pineal tissue. Work on this peptide family was carried out mainly by a research group in Saint Petersburg beginning in the 1980s, and the substance was later registered for clinical use in Russia under the name Epitalon. Outside that region it is generally treated as a research chemical rather than an approved medicine. Statements about its biological activity rest on a relatively small number of studies, and independent replication remains limited.
In its supplied form epitalon is a white to off-white powder, usually lyophilized and often hygroscopic. It dissolves readily in water and in aqueous buffers, and it is commonly handled as the acetate or trifluoroacetate salt to improve stability during purification and drying. The amide backbone is labile in aqueous media, so solutions are less durable than the dry solid. Handling notes in the chemical literature therefore emphasize keeping the powder dry, cool and shielded from light until it is dissolved.
| Property | Value | Notes |
|---|---|---|
| Typical purity specification | 95 percent or higher by HPLC area | Higher grades are also offered |
| Primary analytical method | Reversed-phase HPLC, UV detection | Frequently paired with mass spectrometry |
| Confirmatory technique | Electrospray mass spectrometry | Observed mass compared with theory |
| Storage temperature | Minus 20 degrees Celsius, dry powder | Sealed, desiccated, protected from light |
| Solution handling | Prepare fresh before use | Hydrolysis proceeds in aqueous media |
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.
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.
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.
The published literature is dominated by a small number of research groups, much of it in Russian-language journals, and independent replication outside those groups is limited. Studies are typically small, use cultured cells or rodent models, and report endpoints that differ between papers, which makes comparison difficult. Large randomised human trials have not appeared in the indexed literature. Questions about absorption, distribution and clearance are therefore still treated as open in reviews that mention the compound.
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.
Identity testing for epitalon relies on reversed-phase high-performance liquid chromatography for purity and mass spectrometry for mass confirmation. Because the sequence contains no tryptophan or tyrosine, ultraviolet detection at 280 nanometres is insensitive, so chromatographic methods usually monitor absorbance near 214 nanometres, where the peptide backbone absorbs. Electrospray ionisation or matrix-assisted laser desorption/ionisation then checks the intact mass against the expected value near 390 daltons. Peptide mapping or amino acid analysis after acid hydrolysis can supplement these measurements, although such confirmatory work is seldom reported on commercial certificates of analysis.
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.
=== Oxides === Two oxides of berkelium are known, with the berkelium oxidation state of +3 (Bk2O3) and +4 (BkO2). Berkelium(IV) oxide is a brown solid, while berkelium(III) oxide is a yellow-green solid with a melting point of 1920 °C and is formed from BkO2 by reduction with molecular hydrogen:
== Mechanism of action == Dalbavancin is a lipoglycopeptide belonging in the same glycopeptide class as vancomycin. Similar to other glycopeptides, dalbavancin exerts its bactericidal effect by disrupting cell wall biosynthesis. It binds to the D-alanyl-D-alanyl residue on growing peptidoglycan chains and prevents transpeptidation from occurring, preventing peptidoglycan elongation and cell wall formation. Dalbavancin also dimerizes and anchors itself in the lipophilic bacterial membrane, thereby increasing its stability in the target environment and its affinity for peptidoglycan. Antimicrobial activity correlates with the ratio of area under the concentration-time curve to minimum inhibitory concentration for Staphylococcus aureus.
==== Contact with anti-Chiang organizations ==== Liu was reportedly influenced by the Xi'an Incident and the formation of the Second United Front in 1936, noting that the Communist Party was emerging as a major force in the country. In 1938, Liu Wenhui then reportedly established contact with the Communist Party's Southern Bureau through his in-laws, including general Zhang Zhihe. Zhang Zhihe would become a member of the Central Committee of the China Democratic League (CDL). Another CDL Central Committee member he was in close contact with was Zheng Shufan. Around the time of its establishment in 1941, Liu began providing financial support to the CDL. In September 1944, Liu joined the China Democratic League, becoming a Central Committee member in 1945. Liu's membership, influenced by fellow Sichuan native and CDL chairman Zhang Lan, was kept secret. Peng Dixian, who would later become one of Liu's main biographers, asserts that he established a branch of the CDL in Xikang under Liu's auspices, serving as its chairman. Liu and the CDL would cooperate closely during the later Chengdu Uprising. Over the course of the war with Japan, Liu had also been in contact with generals Li Jishen and Feng Yuxiang, who established the Revolutionary Committee of the Chinese Kuomintang (RCCK) in January 1948. On the urging of Li Jishen, Liu joined in the summer of 1948 as an underground member of the RCCK, becoming the Chairman of its Sichuan branch.
Photodynamic therapy (PDT) is a form of phototherapy using nontoxic light-sensitive compounds (photosensitizers) that are exposed selectively to light at a controlled wavelength, laser intensity, and irradiation time, whereupon they generate toxic reactive oxygen species (ROS) that target malignant and other diseased cells. Oxygen is thus required for activity, lowering efficacy in highly developed tumors and other hypoxic environments. Selective apoptosis of diseased cells is difficult due to the radical nature of ROS, but may be controlled for through membrane potential and other cell-type specific properties' effects on permeability or through photoimmunotherapy. In developing any phototherapeutic agent, the phototoxicity of the treatment wavelength should be considered.
Sources: en.wikipedia.org
==== Revolts of the era of the Spring of Nations ==== The planned national uprising failed to materialize because the authorities in the partitions found out about secret preparations. The Greater Poland uprising ended in a fiasco in early 1846. In the Kraków uprising of February 1846, patriotic action was combined with revolutionary demands, but the result was the incorporation of the Free City of Cracow into the Austrian Partition. The Austrian officials took advantage of peasant discontent and incited villagers against the noble-dominated insurgent units. This resulted in the Galician slaughter of 1846, a large-scale rebellion of serfs seeking relief from their post-feudal condition of mandatory labor as practiced in folwarks. The uprising freed many from bondage and hastened decisions that led to the abolition of Polish serfdom in the Austrian Empire in 1848. A new wave of Polish involvement in revolutionary movements soon took place in the partitions and in other parts of Europe in the context of the Spring of Nations revolutions of 1848 (e.g. Józef Bem's participation in the revolutions in Austria and Hungary). The 1848 German revolutions precipitated the Greater Poland uprising of 1848, in which peasants in the Prussian Partition, who were by then largely enfranchised, played a prominent role.
Organoleptic compounds enhance flavor and aroma. These include fusel oil, methanol, aldehydes, organic acids and esters. Production of isoamyl and isobutyl alcohols begins after the sugar level is lowered substantially and continues for several hours after the alcoholic fermentation ends. In contrast, ethanol production begins in the first hours of the fermentation and ends with logarithmic yeast growth. The alcohol content in tequila is affected by three factors: the amount of isoamyl alcohol and isobutanol in the yeast strain, the carbon:nitrogen ratio (the higher the ratio, the more alcohol produced), and the temperature of fermentation. The higher the temperature, the greater concentration of isobutyl and isoamyl alcohols produced. Although if temperatures are too high, this can cause the yeast to become less effective. Similarly, if the temperature is too low, the process occurs too slowly. This can become a large issue in Central Mexico, where most tequila is processed and where the daytime temperature can reach 31–35 °C. For this reason, tequila producers often use large stainless steel tanks for fermentation.
=== Buccal administration === Progesterone has been studied for use by buccal administration. The medication has been marketed in the form of buccal tablets under the brand names Progesterone Lingusorbs, Lutocylol, Membrettes, and Syngestrets, although these products are no longer available. The clinical dosage of buccal progesterone has been described as 10 to 50 mg/day relative to 5 to 60 mg/day in the case of intramuscular injection.
Sources: en.wikipedia.org
The election was keenly contested; the democratic republicans adopted as their candidate Ledru-Rollin, the "pure republicans" Cavaignac, and the recently reorganized Imperialist party Prince Louis-Napoléon Bonaparte. Unknown in 1835, and forgotten or despised since 1840, Louis Napoleon had in the last eight years advanced sufficiently in the public estimation to be elected to the Constituent Assembly in 1848 by five departments. He owed this rapid increase of popularity partly to blunders of the government of July, which had unwisely aroused the memory of the country, filled as it was with recollections of the Empire, and partly to Louis Napoléon's campaign carried on by means of pamphlets of socialistic tendencies. Moreover, the monarchists, led by Thiers and the committee of the Rue de Poitiers, were no longer content even with the safe dictatorship of the upright Cavaignac, and joined forces with the Bonapartists. On 10 December the peasants gave over 5,000,000 votes to a name: Napoléon, which stood for order at all costs, against 1,400,000 for Cavaignac. Henri Georges Boulay de la Meurthe was elected vice president, a unique position in French history.
== Common uses == The chuck contains large amounts of connective tissue, including collagen, which partially melts during cooking. Meat from the chuck, once divided, is usually used for stewing, slow cooking, braising, or pot roasting and is ideal in a one-pot cooker. The top blade part of the chuck is preferred for grilling because it is the second tenderest steak once the gristle is removed. The fifth rib taken from the chuck can also be used as an alternative to the prime rib roast, which is usually from bones 6–12. They are similar in terms of the proportion of meat and bone, although the fifth rib exceeds the prime rib in the amount of lean meat. The cross-cut or cross rib, which is the last part of the chuck located between the brisket point and the short rib, can also be used as an alternative to the blade when cooking steaks. The chuck part cut from the shoulder clod is also used in place of sirloin since it has a very beefy taste.
== Etymology == The generic name Datura is taken from Hindi धतूरा dhatūra "thorn-apple", ultimately from Sanskrit धत्तूर dhattūra "white thorn-apple" (referring to Datura metel of Asia). In the Ayurvedic text Sushruta Samhita, different species of Datura are also referred to as kanaka and unmatta. Dhatura is offered to Lord Shiva in Hinduism. Record of this name in English dates back to 1662. Nathaniel Hawthorne refers to one type in The Scarlet Letter as "apple-Peru". In Mexico, its common name is toloache (also spelled tolguacha), which derives from the Nahuatl tolohuaxihuitl, meaning "the plant with the nodding head" (in reference to the nodding seed capsules of Datura species belonging to section Dutra of the genus). The term "Jimsonweed" is said to come from the American colony Jamestown. In Jamestown datura was common, and was referred to as "Jamestown-Weed" by one Virginian, Robert Beverley Jr. This then turned into the term "Jimsonweed".
Arsène Charles Ernest Wenger (born 22 October 1949) is a French former football manager and player who has been serving as FIFA's Chief of Global Football Development since 2019. Nicknamed Le Professeur, he is widely regarded as one of the most influential football managers of his generation. Wenger was the manager of Arsenal from 1996 to 2018, becoming the longest-serving and most successful manager in the club's history and the longest-serving manager in the history of the Premier League. Born in Strasbourg and raised in Duttlenheim, Wenger was introduced to football by his father, the manager of the local village team. After a modest playing career as a midfielder, with appearances for clubs including FC Mulhouse and RC Strasbourg, he obtained a manager's diploma in 1981. Wenger began his managerial career at Nancy in 1984 before joining Monaco in 1987. At Monaco, he won the French league title and the Coupe de France in 1991. In 1995, Wenger moved to Japan to manage Nagoya Grampus Eight, where he won both the Emperor's Cup and the Japanese Super Cup. In 1996, Wenger was appointed manager of Arsenal. Initially greeted with scepticism by the English media, he went on to transform the club and English football through innovations in nutrition, training methods, and global scouting. He became the first foreign manager to win a Premier League and FA Cup double in 1998, repeated the feat in 2002, and led Arsenal to an unbeaten league title in 2004. His team later set an English record of 49 consecutive league matches unbeaten.
Sources: en.wikipedia.org
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.
The dry powder is commonly kept at minus twenty degrees Celsius, desiccated and away from light. Solutions are generally prepared fresh because they break down faster than the solid form.
Tandem mass spectrometry or enzymatic peptide mapping can establish residue order. A single intact mass value indicates composition and molecular weight but not always the precise arrangement of residues.
The peptide contains four residues in the order alanine, glutamate, aspartate and glycine, abbreviated AEDG. The chain is linear and held together by three peptide bonds. Its calculated mass for the uncharged free form is about 390.3 daltons.