A practical reference on freeze-thaw: what it is, how it behaves, what the literature reports, and where the honest uncertainties sit.
This page was last updated on 2025-10-27 and is reviewed periodically as new material appears.
Laboratory work indicates that the peptide acts on cells of both the innate and adaptive immune systems. Reported effects include signalling through Toll-like receptors on dendritic cells, enhanced T-cell maturation, and increased natural killer cell activity. These actions are described largely from cell-culture and animal experiments, and the precise receptor-level events remain incompletely defined. Studies in humans have generally measured immune markers rather than a single defined molecular target. The resulting picture remains partly descriptive.
Clinical research has examined the peptide in chronic hepatitis B and C, as a vaccine adjuvant, and in sepsis and oncology settings. Results across trials have been mixed, and several studies were small or conducted under differing protocols. Regulatory status varies by country, and the compound is not approved in every jurisdiction where it is studied. Evidence for any single indication should be read with attention to sample size and endpoint choice.
Thymosin alpha-1 is a 28-residue peptide first isolated from thymus tissue in the 1970s. It corresponds to the N-terminal portion of thymosin beta-4, from which it is cleaved in vivo. The peptide carries an acetyl group at its N-terminus, a modification that affects its charge and stability. Synthetic material produced by solid-phase peptide synthesis is chemically identical to the natural fragment and is the form used in research and clinical studies.
Identity and purity are normally confirmed by reversed-phase high-performance liquid chromatography and mass spectrometry. The expected mass for the acetylated 28-residue peptide is close to 3108 daltons, and a mass shift indicates a modification or truncation. Peptide mapping after enzymatic digestion can resolve sequence-level questions. Counter-ion content, water content, and residual solvents are separate quality attributes that a certificate of analysis may or may not report. Aggregation is monitored by size-exclusion chromatography when relevant.
Thymosin alpha-1 is supplied as a lyophilized powder in most research settings. The solid dissolves readily in water and in common aqueous buffers, and it is typically reconstituted shortly before use. Solutions are clear and colourless at ordinary working concentrations. Because the peptide is hygroscopic, weighing and reconstitution are usually performed with minimal exposure to ambient air. Aliquots are prepared to avoid repeated freeze-thaw cycles, and working solutions are kept cold.
| Property | Value | Notes |
|---|---|---|
| Chemical class | Peptide | 28 amino acid residues |
| Molecular weight | Approximately 3108 Da | Depends on acetylation state |
| N-terminal modification | Acetylated | Affects charge and stability |
| Natural source | Fragment of thymosin beta-4 | Cleaved in vivo |
| Sequence length | 28 residues | Synthetic form matches natural |
20世纪70年代，研究者从胸腺提取物中纯化出多种小肽，Tα1是其中被较早表征的一种。最初的制备依赖组织匀浆和层析步骤，产量低且成分复杂。随着固相肽合成技术成熟，实验室和工业界能够生产与天然序列一致的合成版本。合成肽的纯度可达95%以上，并可通过反相高效液相色谱和质谱进行鉴定。这一转变使研究不再依赖动物胸腺来源。
市售的胸腺素α1通常以冻干粉形式提供，溶解后用于注射。其氨基酸组成包括多个酸性残基，因此在中性pH下带负电荷。该肽可溶于水和生理盐水，但在有机溶剂中溶解度有限。储存条件通常为冻干状态下负20摄氏度，溶解后需冷藏并避免反复冻融。常见的同义词包括胸腺肽α1、thymalfasin和Tα1。
临床研究将Tα1用于慢性病毒感染、肿瘤辅助治疗和疫苗佐剂等场景。部分试验报告了免疫学指标改善，但临床终点获益在不同研究中并不一致。系统综述指出，研究间在人群、剂量和联合方案上差异较大，难以汇总结论。因此，Tα1的确切临床地位仍属开放问题，需要更多高质量随机对照试验来澄清。其机制研究也需从体外实验向体内模型推进。
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。
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.
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.
Lyophilized material is generally held at reduced temperature to slow degradation, and storage at minus twenty degrees Celsius or lower is common practice for long-term retention. Short-term working portions are often kept between two and eight degrees Celsius. Once dissolved, the peptide is less stable than the dry powder, and repeated freeze-thaw cycles are associated with loss of material and with aggregate formation. Vials are usually allowed to reach room temperature before opening so that condensation does not introduce moisture, and solutions are protected from light where practical.
Identity and purity are assessed mainly by reversed-phase high-performance liquid chromatography, which separates the peptide from closely related impurities and from truncated or oxidized variants. Mass spectrometry supplies the molecular mass and confirms the expected sequence length, while amino acid analysis can be used to check composition. Because the molecule has no chromophore beyond the peptide backbone, ultraviolet detection is typically performed at a low wavelength, where baseline interference from solvents and buffers is a practical concern. Water content and counter-ion content are often reported alongside purity.
== Treatment == Supervised exercise programs have been shown in small studies to improve exercise capacity by several measures: lowering heart rate, lowering serum creatine kinase (CK), increasing the exercise intensity threshold before symptoms of muscle fatigue and cramping are experienced, and the skeletal muscles becoming aerobically conditioned. Oral sucrose treatment (for example a sports drink with 75 grams of sucrose in 660 ml.) taken 30 minutes before exercise has been shown to help improve exercise tolerance, including a lower heart rate and lower perceived level of exertion compared with placebo. This is because the ingestion of a high-carbohydrate meal or drink causes transient hyperglycaemia, with the exercising muscle cells utilizing the high glucose in the blood for the glycolytic pathway. However, the ingestion of a high-carbohydrate meal or drink is problematic as a frequent form of treatment since it will increase the release of insulin, which inhibits the release of fatty acids and subsequently will delay the ability to get into second wind. The frequent ingestion of sucrose (e.g. sugary drinks), to avoid premature muscle fatigue and cramping, is also problematic in that it can lead to obesity as insulin will also stimulate triglyceride synthesis (develop body fat), and obesity-related ill health (e.g. type II diabetes and heart disease). A low dosage treatment with creatine showed a significant improvement of muscle problems compared to placebo in a small clinical study, while other studies have shown minimal subjective benefit.
While they are often significantly more expensive, they can give a water proof material that has useful tensile strength. Sorel cement is a hard, durable cement made by combining magnesium oxide and a magnesium chloride solution Electric cement is proposed to be made by recycling cement from demolition wastes in an electric arc furnace as part of a steelmaking process. The recycled cement is intended to be used to replace part or all of the lime used in steelmaking, resulting in a slag-like material that is similar in mineralogy to Portland cement, eliminating most of the associated carbon emissions.
The process of termination by Rho factor is regulated by attenuation and antitermination mechanisms, competing with elongation factors for overlapping utilization sites (ruts and nuts), and depends on how fast Rho can move during the transcription to catch up with the RNA polymerase and activate the termination process. Inhibition of Rho dependent termination by bicyclomycin is used to treat bacterial infections. The use of this mechanism along with other classes of antibiotics is being studied as a way to address antibiotic resistance, by suppressing the protective factors in RNA transcription while working in synergy with other inhibitors of gene expression such as tetracycline or rifampicin.
Sunak announces that former prime minister Johnson will endorse Conservative candidates by writing to constituents urging them not to vote for Reform, saying to do so will "make a difference". The state visit of Japan's Emperor Naruhito is to be modified to omit the usual visit to 10 Downing Street because it coincides with the election. Scottish Labour launches its general election manifesto. Businessman John Caudwell, the founder of Phones4U, who gave the Conservatives a £500,000 donation before the 2019 general election, tells the BBC he will be voting Labour for the first time in his life at the 2024 election. During an election debate on BBC Radio 4's Woman's Hour, representatives from Labour, the Liberal Democrats, Greens and Scottish National Party express their support for making misogyny a hate crime. 19 June – A police officer working as part of the prime minister's close protection team is suspended and later arrested as part of an ongoing investigation into bets on the date of the general election. The Scottish National Party launches its election manifesto, with plans to "end Westminster cuts" and increase investment in the NHS. The party would also view winning a majority of Scotland's seats at Westminster as a mandate to begin independence negotiations. Labour suspends Andy Brown, its candidate for Aberdeenshire North and Moray East after he was found to have shared pro-Russian posts online. The Scottish Family Party launches its election manifesto, chiefly promoting family values.
Živojinović (nicknamed Bata) was born in the village of Koraćica under the Kosmaj mountain near Mladenovac, at the time Kingdom of Yugoslavia (now Serbia). His father, Dragoljub, was an official and his mother Tiosava was a housewife. He had two sisters, Stanka and Nada, and grew up in a patriarchal household. A conflict between Dragoljub and the Chetniks during World War II forced the family to move to Belgrade. The family lived in Crveni Krst. Young Bata often went with his friends to the cinema, which sparked his interest in acting. Loitering around the "20th October" cinema, he watched AKUD Branko Krsmanović, a Belgrade troupe, through the window for several days until he was welcomed inside. There he befriended Soja Jovanović, instrumental in the developing of Bata's love for acting, Rade Marković, Olivera Marković, Mića Tomić, and Bata Paskaljević. After graduating from acting schools in Niš and Novi Sad, he enrolled at the Drama Academy in Belgrade.
Sources: en.wikipedia.org
== External links == Cobalt-60, Centers for Disease Control and Prevention. NLM Hazardous Substances Databank – Cobalt, Radioactive Beta decay of Cobalt-60, HyperPhysics, Georgia State University. Dr. Henry Kelly (March 6, 2002). "Cobalt-60 as a Dirty Bomb". Federation of American Scientists. Archived from the original on April 5, 2002. Retrieved November 26, 2005.
Rongliflozin/Olorigliflozin has been evaluated in phase I trials, but is not yet approved by the FDA Sergliflozin etabonate discontinued after phase II trials. Sotagliflozin (Inpefa) is a dual SGLT1/SGLT2 inhibitor approved by the US Food and Drug Administration (FDA) in May 2023, to reduce the risk of cardiovascular death, hospitalization for heart failure, and urgent heart failure visit in adults with heart failure or type 2 diabetes, chronic kidney disease, and other cardiovascular risk factors. Tofogliflozin, developed by Sanofi and Kowa Pharmaceutical, was approved in Japan in March 2014, under the brand names Apleway and Deberza. Velagliflozin, marketed as Senvelgo, produced by Boehringer Ingelheim Animal Health, was approved for use in diabetic cats in 2023.
==== Post reform organisations ==== The 1st Hydropower Corps was converted into the China Anneng Construction Group's 1st Engineering Bureau (Headquartered in Nanning) on 19 November 2019. The 2nd Hydropower Corps was converted into the China Anneng Construction Group's 2nd Engineering Bureau (Headquartered in Nanchang) on 14 November 2019. The 3rd Hydropower Corps was converted into the China Anneng Construction Group's 3rd Engineering Bureau (Headquartered in Chengdu) on 12 November 2019. It has branches in Wuhan and Chongqing.
platelet-derived growth factor transforming growth factor beta fibroblast growth factor insulin-like growth factor 1 insulin-like growth factor 2 vascular endothelial growth factor A vascular endothelial growth factor C epidermal growth factor interleukin 8 keratinocyte growth factor connective tissue growth factor hepatocyte growth factor stromal cell-derived factor 1 endostatin
Sources: en.wikipedia.org
The Wound Man is a surgical diagram which first appeared in European medical manuscripts of the fourteenth and fifteenth centuries. The illustration acted as an annotated table of contents to guide the reader through various injuries and diseases whose related cures could be found on the text's nearby pages. The image first appeared in a printed book in 1491 when it was included in the Venetian Fasciculus medicinae, likely Europe's first printed medical miscellany. Thereafter it circulated widely in printed books until well into the seventeenth century. The Wound Man has since become a recognisable figure in popular culture.
== Detection == Alan Fryday (1991) outlined a technique for the detection of confluentic acid in lichen samples. This method involves placing a section of the lichen's thallus or apothecium (fruiting body) on a microscope slide, which is then saturated with a 10% potassium hydroxide (KOH) solution. When examined under a compound microscope at 40x magnification, a distinctive 'halo' of small oil droplets or bubbles emanating from the tissue section indicates the presence of confluentic acid. The oil droplets generated during this detection process consist of 4-O-methylolivetonide, a compound that is insoluble in potassium hydroxide solution. This substance forms as a result of confluentic acid undergoing hydrolysis in the presence of potassium hydroxide. This test is useful in distinguishing between morphologically similar yet chemically distinct species within the genus Porpidia.
== Applications == Metamaterials are under consideration for many applications. Metamaterial antennas are commercially available. In 2007, one researcher stated that for metamaterial applications to be realized, energy loss must be reduced, materials must be extended into three-dimensional isotropic materials and production techniques must be industrialized. All-dielectric subwavelength metasurface focusing lens operating in the near infrared has been demonstrated by the Shalaev group in collaboration with the Raytheon team. This lens is currently used in Raytheon defense system products.
=== 21 March === The SAF retook the Republican Palace in Khartoum from the RSF. An RSF drone strike on the palace that same day killed six journalists including two military reporters and four members of a Sudan TV crew.
It is the process where new blood vessels form from pre-existing ones. This happens naturally when the body needs to repair tissue or when a wound needs to heal. It is driven by signals from growth factors, such as Vascular Endothelial Growth Factor (VEGF), which prompts the formation of new vessels. However, this process can occasionally go wrong in tumour formation where it allows the tumours to create their own blood supply and grow larger, which can contribute to diseases like cancer. Angiogenesis is the most common type of neovascularization seen in development and growth, and is important to both physiological and pathological processes. Angiogenesis occurs through the formation of new vessels from pre-existing vessels. This occurs through the sprouting of new capillaries from post-capillary venules, requiring precise coordination of multiple steps and the participation and communication of multiple cell types. The complex process is initiated in response to local tissue ischemia or hypoxia, leading to the release of angiogenic factors such as VEGF and HIF-1. This leads to vasodilatation and an increase in vascular permeability, leading to sprouting angiogenesis or intussusceptive angiogenesis.
Sources: en.wikipedia.org
It corresponds to the first 28 amino acids of thymosin beta-4, a larger protein found in many tissues. The fragment is acetylated at its N-terminus and is produced synthetically for research and pharmaceutical use. Synthetic and natural forms share the same sequence.
It is usually described as an immunomodulatory peptide rather than a classical hormone. It does not travel to a single distant organ in the manner of an endocrine hormone. Classification varies across sources, and some texts group it with thymic peptides generally.
The broad outline involves immune cell activation, but the specific molecular steps remain under investigation. Different studies report effects on dendritic cells, T cells, and natural killer cells. No single receptor has been confirmed as the sole mediator.
Lyophilized powder is normally kept at minus twenty degrees Celsius or below, in a sealed container, desiccated and away from light. Reconstituted solutions are less stable and are usually refrigerated and used quickly. Repeated temperature cycling should be avoided.