If you have been reading about counter-ion and want a single page that covers the useful parts, this is it: definitions, context, how it is studied, and the questions that come up repeatedly.
Last reviewed on 2026-02-11. Where a claim depends on a specific study, the study is described rather than over-claimed.
Clinical interest has centered on chronic viral hepatitis, on immune restoration in various conditions, and on use as an adjuvant intended to improve responses to vaccines. Trials have reported mixed results, and regulatory status differs sharply between countries; in some places it is a prescription product, while elsewhere it is sold without an approved therapeutic indication. Because published studies vary widely in design, population, and endpoints, comparisons across them are difficult and no single conclusion covers the whole literature.
Thymosin alpha 1 is a short peptide of 28 amino acid residues that derives from the amino terminal region of a larger precursor protein known as prothymosin alpha. The peptide carries an acetyl group on its first residue and contains no disulfide bonds or carbohydrate chains. Its sequence is highly conserved across mammalian species, which is one reason laboratories treat it as a molecule with a defined and reproducible structure rather than a variable tissue extract. The name follows an early naming convention for thymus-derived fractions and does not imply that the peptide acts as a hormone in the classical endocrine sense.
Biologically, the peptide is studied mainly in the context of immune cell development and regulation. It is produced in the thymus and in several other tissues, and it appears to influence the maturation and activity of T cells and other immune populations. Laboratory work describes effects on cytokine production, on the balance between T cell subsets, and on the function of dendritic cells. Much of this evidence comes from cell culture and animal models, so the extent to which the same pathways operate in humans remains an open question.
Several factors accelerate degradation: alkaline pH, elevated temperature, exposure to oxidants, and the presence of residual moisture. Deamidation of asparagine residues and oxidation of methionine are the most commonly reported degradation routes. Because the peptide lacks disulfide bonds, it does not undergo the thiol-related aggregation seen in some other biologics, but physical aggregation can still occur at high concentration. Stability data are product-specific, and extrapolating shelf life between formulations is not reliable.
Lyophilized thymosin alpha-1 is generally stored at or below minus twenty degrees Celsius, protected from moisture and light. Short-term handling at ambient temperature is possible for dry powder, but reconstituted solutions degrade faster and are usually kept at two to eight degrees Celsius with a defined expiry of days rather than weeks. Repeated freeze-thaw cycles should be avoided because they promote aggregation and loss of potency. Exact limits depend on the formulation and should follow the supplier's documentation.
| Property | Value | Notes |
|---|---|---|
| Molecular mass | Approximately 3,108 Da | Consistent with a 28-residue acetylated peptide |
| Residue count | 28 | Corresponds to the amino terminal region of prothymosin alpha |
| Appearance of dry powder | White to off-white solid | Slight variation between lots is normal |
| Solubility class | Freely soluble in water | Low solubility in most organic solvents |
| Common synonyms | Thymosin alpha 1, T alpha 1 | The numeral reflects an early fraction numbering scheme |
Stability depends on temperature, pH, and the number of freeze-thaw events the sample has experienced. Freeze-dried material is commonly held at -20 °C or colder, while reconstituted liquid is kept cold and used within a short window. Extreme pH and prolonged light exposure can promote deamidation, oxidation, or aggregation, particularly at asparagine and methionine positions. Adsorption to container walls can lower the measured concentration of a dilute solution even when the peptide molecules themselves remain intact.
Identity and purity are usually assessed by reversed-phase high-performance liquid chromatography, which separates the target peptide from truncated or chemically modified byproducts. Mass spectrometry confirms the expected molecular mass and can indicate acetylation state or sequence errors. Amino acid analysis and peptide mapping supply complementary sequence-level information, while endotoxin testing is relevant for preparations intended for cell or animal work. Purity figures reported by suppliers refer to the method used and are not directly comparable across laboratories unless conditions are stated.
Lyophilized material is typically treated as a hygroscopic solid that should be brought to room temperature before the container is opened, which limits condensation on the powder. Reconstitution is commonly done with sterile water or a buffered diluent, and gentle mixing is preferred over vigorous agitation to reduce foaming and surface adsorption. Because peptides can bind to plastic and glass, diluents containing a small amount of carrier protein are sometimes used in laboratory work. Working solutions are generally aliquoted and prepared fresh rather than subjected to repeated freezing and thawing.
胸腺素α1对免疫系统的影响涉及多种细胞类型。研究表明，它可促进未成熟T细胞向成熟T细胞分化，并增强T细胞对抗原刺激的增殖反应。树突状细胞在Tα1存在下表达更高水平的共刺激分子，从而更有效地呈递抗原。此外，自然杀伤细胞的活性也观察到上升。这些效应并非直接杀伤病原体，而是调节宿主免疫应答的强度与方向。
在信号层面，Tα1可能通过Toll样受体等模式识别受体发挥作用。部分实验显示，它能激活髓样分化因子88依赖的通路，进而促进核因子κB进入细胞核。这导致白细胞介素2、干扰素γ和白细胞介素12等细胞因子的转录增加。这些细胞因子偏向辅助性T细胞1型应答，有助于细胞免疫。然而，具体受体和结合位点尚未完全确定，不同实验模型的结果存在差异。
During World War II, German Type XXI submarines (also known as "Elektroboote") were the first submarines designed to operate submerged for extended periods. Initially they were to carry hydrogen peroxide for long-term, fast air-independent propulsion, but were ultimately built with very large batteries instead. At the end of the War, the British and Soviets experimented with hydrogen peroxide/kerosene (paraffin) engines that could run surfaced and submerged. The results were not encouraging. Though the Soviet Union deployed a class of submarines with this engine type (codenamed Quebec by NATO), they were considered unsuccessful. The United States also used hydrogen peroxide in an experimental midget submarine, X-1. It was originally powered by a hydrogen peroxide/diesel engine and battery system until an explosion of her hydrogen peroxide supply on 20 May 1957. X-1 was later converted to use diesel–electric drive. Today several navies use air-independent propulsion. Notably Sweden uses Stirling technology on the Gotland-class and Södermanland-class submarines. The Stirling engine is heated by burning diesel fuel with liquid oxygen from cryogenic tanks. A newer development in air-independent propulsion is hydrogen fuel cells, first used on the German Type 212 submarine, with nine 34 kW or two 120 kW cells. Fuel cells are also used in the new Spanish S-80-class submarines although with the fuel stored as ethanol and then converted into hydrogen before use.
For each diprotic acid titration curve, from left to right, there are two midpoints, two equivalence points, and two buffer regions. Due to the successive dissociation processes, there are two equivalence points in the titration curve of a diprotic acid. The first equivalence point occurs when all first protons from the first ionization are titrated. In other words, the amount of OH− added equals the original amount of H2A at the first equivalence point. The second equivalence point occurs when all protons are titrated. Therefore, the amount of OH− added equals twice the amount of H2A at this time. For a weak diprotic acid titrated by a strong base, the second equivalence point must occur at pH above 7 due to the hydrolysis of the resulted salts in the solution. At either equivalence point, adding a drop of base will cause the steepest rise of the pH value in the system.
The investigation by Science and the NIH was triggered by whistleblowers who delivered a 113 page dossier to Science. The dossier presented evidence that patients treated with 3K3A-APC died at a higher rate in the first week following treatment than those on the placebo (6 out of 66 versue 1 out 44). Also, patients on the drug suffered more disability. The dossier also claimed that data had been doctored in dozens of papers from Zlokovic's lab. Wade Smith, a University of California, San Francisco neurologist and StrokeNet principal investigator said that “I think pausing the trial until any impact of potential impropriety in preclinical drug testing is resolved to ensure the compound is safe for humans is the correct pathway to follow. This drug may work in humans so discarding it would be a shame,” he adds. “Alternatively, moving forward with a compound that may be unsafe is worse.”
Radium-226 (226Ra) is the longest-lived isotope of radium, with a half-life of 1600 years. It is an intermediate product in the decay chain of uranium-238; as such, it can be found naturally in uranium-containing minerals.
The term psychiatry was first coined by the German physician Johann Christian Reil in 1808 and literally means the 'medical treatment of the soul' (ψυχή psych- 'soul' from Ancient Greek psykhē 'soul'; -iatry 'medical treatment' from Gk. ιατρικός iātrikos 'medical' from ιάσθαι iāsthai 'to heal'). A medical doctor specializing in psychiatry is a psychiatrist (for a historical overview, see: Timeline of psychiatry).
Sources: en.wikipedia.org
== Bilingual status == Under the University College Galway Act, 1929 (which came into effect on 17 December 1929), the university was given special statutory responsibility with respect of the use of the Irish language as a working language of the university. The Act of 1929 provided that when recruiting a person to work for the university, a person competent in the Irish language must be appointed to the position unless no such person with the necessary competence to carry out the role could be found among the candidates for the position. As a result, every president appointed to the university thereafter was fluent in Irish. The university's governing authority complained that this requirement limited the pool of potential candidates for the office of president (in particular, candidates from overseas). As a result, the Act was amended in 2006 to replace the requirement for fluency in the Irish language amongst staff and management with a commitment to provide for education through the Irish language. In 2016, the university amended its recruitment criteria to allow for the possibility of a non-Irish-speaking president. In August 2025, a non-Irish-speaking president was appointed to the university for the first time since the appointment of Alexander Anderson in 1899.
== Uses == It is used as a wood product and in folk medicine. This valuable wood was used in Chinese furniture from the late Ming and early Qing dynasties, and new furniture in the same styles are sought after as luxury and prestige items.
Dual polarisation interferometry is a surface-based technique for measuring the optical properties of molecular layers. When used to characterize protein folding, it measures the conformation by determining the overall size of a monolayer of the protein and its density in real time at sub-Angstrom resolution, although real-time measurement of the kinetics of protein folding are limited to processes that occur slower than ~10 Hz. Similar to circular dichroism, the stimulus for folding can be a denaturant or temperature.
== Use and effects == (R)-MDMA has a dose of 125 to 300 mg orally and a duration of 3.5 to 5.2 hours. It has been estimated that doses of 125 mg MDMA, 100 mg (S)-MDMA, and 300 mg (R)-MDMA are equivalent. The first modern clinical study of the comparative effects of MDMA, (R)-MDMA, and (S)-MDMA was published in August 2024. It compared 125 mg MDMA, 125 mg (S)-MDMA, 125 and 250 mg (R)-MDMA, and placebo. (R)-MDMA increased any drug effect, good drug effect, drug liking, stimulation, drug high, alteration of vision, and alteration of sense of time ratings similarly to MDMA and (S)-MDMA. However, (S)-MDMA 125 mg was more potent in increasing subjective effects, including stimulation, drug high, happy, and open, among others, than (R)-MDMA 125 or 250 mg or MDMA 125 mg. Ratings of bad drug effect and fear were minimal with MDMA, (R)-MDMA, and (S)-MDMA. In contrast to expectations, (R)-MDMA did not produce more psychedelic-like effects than (S)-MDMA. Besides subjective effects, (R)-MDMA increased heart rate, blood pressure, and body temperature similarly to MDMA and (S)-MDMA, though it was less potent in producing these effects. Body temperature was notably increased to the same extent with (R)-MDMA 250 mg as with MDMA 125 mg and (S)-MDMA 125 mg. The differences in effects between (R)-MDMA and (S)-MDMA may reflect the higher potency of (S)-MDMA rather than actual qualitative differences between the effects of (S)-MDMA and (R)-MDMA. It was estimated that equivalent effects would be expected with (S)-MDMA 100 mg, MDMA 125 mg, and (R)-MDMA 300 mg.
Sources: en.wikipedia.org
== Clinical significance == Patients with chronic diarrhea due to bile acid malabsorption have been shown to have reduced fasting FGF19. Surgical resection of the ileum (as often occurs in Crohn's disease) will reduce bile acid absorption and remove the stimulus for FGF19 production. In primary bile acid diarrhea, absorption of bile acids is usually normal, but defective FGF19 production can produce excessive bile acid synthesis, as shown by increased levels of 7α-hydroxy-4-cholesten-3-one, and excessive bile acid fecal loss, indicated by reduced SeHCAT retention. This was confirmed in a prospective study of patients with chronic diarrhea, where the predictive value for FGF19 in diagnosis of primary bile acid diarrhea and response to bile acid sequestrants was demonstrated. FGF19 is also found in the liver of patients with cholestasis. It can be synthesised in the gall-bladder and secreted into bile. FGF19 is expressed in around half of hepatocellular carcinomas and was associated with larger size, early recurrence and poor prognosis. Patients with the metabolic syndrome, non-alcoholic fatty liver disease and insulin resistance have reduced levels of FGF19. FGF19 increases to normal values in obese patients who undergo Roux-en-Y gastric bypass and other types of bariatric surgery.
Hilleman also developed the first Hepatitis B vaccine and the first varicella vaccine, for chickenpox. The company was incorporated in New Jersey in 1970. John J. Horan became CEO and Chairman in 1976, serving until 1985. Under his leadership, the company's investment in R&D grew threefold, and Merck became the largest pharmaceutical company in the world. In 1979, Merck scientists developed lovastatin (Mevacor), the first drug of the statin class. Merck scientist William C. Campbell and Satoshi Ōmura developed ivermectin for veterinary use in 1981, and later put it to human use against onchocerciasis in 1987–1988 with the name Mectizan; today the compound is also used against lymphatic filariasis, scabies and other parasitic infections. In 1982, the company formed a joint venture, KBI Inc., with AstraZeneca. During the late 1980s and 1990s, the company also established joint ventures with DuPont to access research and development expertise, and with Johnson & Johnson to sell over-the-counter consumer medications. In 1985, Merck received approval for imipenem, the first member of the carbapenem class of antibiotics. Antibiotics of the carbapenem class play an important role in treatment guidelines for certain hospital-acquired and multi-drug resistant infections. P. Roy Vagelos became CEO and Chairman that year, succeeding Horan. Vagelos served until reaching the company's mandatory retirement age in 1994, succeeded by Raymond Gilmartin. In 1991, Merck's Kelco subsidiary was responsible for volatile organic compound (VOC) emission pollution in the San Diego area.
The gastric inhibitory polypeptide receptor (GIP-R), also known as the glucose-dependent insulinotropic polypeptide receptor, is a protein that in humans is encoded by the GIPR gene. GIP-R is a member of the class B family of G protein–coupled receptors. GIP-R is found on beta-cells in the pancreas, where it serves as the receptor for the gastric inhibitory polypeptide (GIP).
Sources: en.wikipedia.org
The name reflects an early convention for naming thymus-derived fractions. The peptide is characterized and measured as a defined molecule, and it does not operate through a single classical endocrine axis.
Dry lyophilized powder tolerates short ambient exposure during handling and shipping. Long-term room-temperature storage is not recommended because moisture uptake and slow degradation can occur over months. Storage at minus twenty degrees Celsius is the common practice for extended periods.
Typical entries list appearance, identity by mass spectrometry, purity by chromatography, water or moisture content, and residual counter-ion. Some certificates also report microbial limits and endotoxin for materials intended for laboratory use. The reported methods and acceptance ranges vary between suppliers.
The peptide is often supplied as an acetate or trifluoroacetate salt, and the counter-ion affects solubility, weight-per-mole calculations, and compatibility with cell assays. Trifluoroacetate can be undesirable in some biological experiments. Knowing the salt form is necessary for accurate concentration determination.