RP-HPLC raises a handful of sensible questions. This page answers them in order, starting with the fundamentals and moving to applications.
Reviewed 2026-07-26. Anything still debated is marked as such rather than presented as settled.
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。
胸腺素α1（thymosin alpha 1，Tα1）是一种由28个氨基酸组成的酸性肽，N端被乙酰化，分子量约为3108道尔顿。该肽最早从牛胸腺组织提取物中分离，属于胸腺素组分5的一个成分。其序列在不同哺乳动物中高度保守，提示其具有基本的生物学功能。名称中的“α1”指其在电泳中的迁移位置，并非表示亚型编号。它既存在于胸腺，也存在于脾脏和淋巴结等免疫组织。
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。
Long-term storage is generally at minus twenty degrees Celsius or colder, preferably desiccated and protected from light. Lyophilized material is more stable than reconstituted solution, which degrades faster at room temperature. Stability depends on pH, ionic strength, and the presence of oxidising agents. Published stability data for the peptide are limited, so storage claims in catalogues should be treated as general guidance rather than measured guarantees. Freeze-thaw cycles are kept to a minimum.
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 |
|---|---|---|
| 化学分类 | 线性肽 | 由28个氨基酸组成 |
| 分子量 | 约3108 Da | 合成版本一致 |
| 外观 | 白色至类白色粉末 | 冻干品 |
| 溶解度 | 易溶于水 | 微溶于有机溶剂 |
| 储存温度 | -20°C（冻干） | 溶解后2-8°C |
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.
Quality control for thymosin alpha-1 focuses on identity, purity, and potency. Identity is confirmed by mass spectrometry and amino acid analysis, while purity is assessed by chromatography with limits on related substances and residual solvents. Potency assays may use cell-based immune readouts, but these are not standardized across laboratories. Regulatory status differs by jurisdiction; no product is approved in the United States for clinical use, whereas some other countries register injectable forms for specific indications.
Quantifying thymosin alpha-1 in a sample usually relies on reverse-phase high-performance liquid chromatography. The peptide lacks strong chromophores, so detection often occurs at 214 nm, where the peptide backbone absorbs. Mass spectrometry provides confirmatory identification and can detect sequence variants or truncations. Immunoassays have been used in biological matrices, but they may cross-react with related fragments. For purity assessment, chromatographic peak area gives the main component percentage, while mass accuracy verifies molecular identity.
Overall evidence quality varies considerably. A large share of published reports come from single centers, rely on surrogate immunological markers, or lack adequate control groups. Systematic reviews have highlighted this heterogeneity as a barrier to pooling results. Open questions include which patients, if any, might benefit, what treatment duration is appropriate, and whether any effect is independent of standard care. The peptide is often described as an immune modulator rather than a therapy for one disease, which complicates confirmatory trial design.
Thymosin alpha 1 was identified in 1977 as a component of thymosin fraction 5, a heterogeneous preparation used in early studies of thymic function. Investigators purified the active material and determined its amino acid sequence, which enabled chemical synthesis. Work in the following decades concentrated on T-cell maturation and immune reconstitution in animals and small human cohorts. Early preparations varied in composition, so results from that period are difficult to compare with studies using defined synthetic peptide.
Clinical research has examined the peptide in chronic hepatitis B and C, as a vaccine adjuvant, and in sepsis and oncology settings. Findings across trials are mixed; some report changes in selected immune markers, while others find no clear clinical benefit. Many studies are small and define outcomes differently, which limits comparison. Regulatory approval is confined to a few countries, and the compound is not an approved drug in the United States or most of Europe.
The peptide occurs naturally in thymic tissue and has been detected in serum and other biological fluids. Reported concentrations are low, and reliable measurement generally requires immunoassay or mass spectrometry with an enrichment step. It is released from a larger precursor, prothymosin alpha, by proteolytic cleavage, although the enzymes involved are not fully characterized. Whether circulating levels reflect thymic output specifically remains an open question.
Thymosin alpha 1 is a 28-amino-acid peptide first isolated from thymosin fraction 5, a bovine thymic extract. Its sequence begins with an acetylated serine residue and carries a high proportion of acidic residues, so the molecule has a net negative charge near neutral pH. Despite the shared name, it is unrelated in sequence to the thymosin beta family. Synthetic material prepared by solid-phase peptide synthesis is identical in sequence to the natural peptide.
Several names appear in the literature for this peptide, including thymalfasin and the abbreviation T-alpha-1. Naming conventions differ among research articles, regulatory documents, and supplier catalogs, which complicates literature searches. Both synthetic and recombinant production routes yield a peptide with the same 28-residue sequence as the thymic isolate. Because the thymosin label also covers unrelated peptides, sources should be compared by sequence rather than by name alone.
Tunable metamaterials allow arbitrary adjustments to frequency changes in the refractive index. A tunable metamaterial expands beyond the bandwidth limitations in left-handed materials by constructing various types of metamaterials.
Materials characterization (spectroscopy, microscopy, diffraction) Computational materials science Materials informatics and selection There are also relatively broad focuses across materials on specific phenomena and techniques.
=== Alternative treatments for wounds: leeches and maggots === Medical leeches were cleared as a medical device in 2004 after being an indispensable tool in the 19th century and even in use in the Middle Ages. This unique use of creatures is utilized in many surgeries today. Leeches have the ability to assist with compromised tissue with the components of their saliva. Their saliva contains a local anesthetic, thrombin inhibitor, antibiotic properties and a histamine-like vasodilator. These capabilities help in surgeries such as transplants, skin grafts, and even reconstructive surgeries. The leeches help localize the wound and help produce blood flow. This is helpful in operations where blood clots occur and they help dilate the blood vessels. Baron Dominique Jean Larrey, surgeon-in-chief of Napoleon's Grande Armée pioneered the use of maggots to prevent infection in wounds. They were also used by military medical aids during World War II. They worked as biomedical debriding agents by ingesting bacteria and breaking them down within their intestines. Maggots give off an enzyme that disinfects wounds and promotes healing and this is why they became the first organism in the United States that were used as a medical device in January 2004.
During the Cold War, much of the policy and the infrastructure of the Western world and the Eastern Bloc had revolved around the capitalist and communist ideologies, respectively, and the possibility of a nuclear warfare. The end of the Cold War and the fall of the Soviet Union caused profound changes in nearly every society in the world. It enabled renewed attention to be paid to matters that were ignored during the Cold War and has paved the way for greater international cooperation, international organizations, and nationalist movements. The European Union expanded and further integrated, and power shifted from the G7 to the larger G20 economies. The outcome symbolized a victory of democracy and capitalism which became a manner of collective self-validation for countries hoping to gain international respect. With democracy being seen as an important value, more countries began adopting that value. Communism ended also in Mongolia, Congo, Albania, Yugoslavia, Afghanistan, and Angola. As of 2023, only five countries in the world are still ruled as communist states: China, Cuba, North Korea, Laos, and Vietnam.
Sources: en.wikipedia.org
Registered voters: 425,305, valid: 371,189, turnout: 87.3% To honour the exceptionally high percentage of pro-German votes in the district of Oletzko, with 2 votes for Poland compared to 28,625 for Germany, the district town Marggrabowa (i.e. Margrave town) was renamed "Treuburg" (TreueGerman = "loyalty") in 1928, with the district following this example in 1933. In the villages of Lubstynek (Klein Lobenstein), Czerlin (Klein Nappern) and Groszki (Groschken) in the District of Osterode in East Prussia (Ostróda), situated directly at the border, the majority voted for Poland and joined Poland after the plebiscite. Other Polish-majority villages were scarce but would have been more numerous if they had not been surrounded by Mazurian German disposed villages, which made a geographical connection with Poland improbable and so votes for Poland would not be useful. The strategic importance of the Prussian Eastern Railway line Danzig-Warsaw passing through the area of Soldau in the Neidenburg District caused it to be transferred to Poland without a plebiscite; it was renamed Działdowo.[1]
restriction fragment length polymorphism (RFLP) Variability within a population of organisms observed in the size of the restriction fragments produced when genomic DNA (or any particular DNA molecule) is digested by one or more restriction endonucleases. This variability results from a corresponding polymorphism in the locations of restriction sites within the molecule(s) due to slight differences in nucleotide sequence between individuals. RFLP is frequently exploited in the laboratory to construct physical maps of the genome, to identify the specific locus occupied by a particular gene, and to detect genetic differences between closely related individuals or determine that different samples originated from the same individual. Analysis of restriction fragments can also reveal the presence of a mutation that may itself cause disease or be closely linked to one that does.
A characterization of these fibers was given, as well as hypotheses for their growth in a nitrogen atmosphere at low pressures. In 1981, a group of Soviet scientists published the results of chemical and structural characterization of carbon nanoparticles produced by a thermocatalytic disproportionation of carbon monoxide. Using TEM images and XRD patterns, the authors suggested that their "carbon multi-layer tubular crystals" were formed by rolling graphene layers into cylinders. They speculated that via this rolling, many different arrangements of graphene hexagonal nets are possible. They suggested two such possible arrangements: a circular arrangement (armchair nanotube); and a spiral, helical arrangement (chiral tube). In 1987, Howard G. Tennent of Hyperion Catalysis was issued a U.S. patent for the production of "cylindrical discrete carbon fibrils" with a "constant diameter between about 3.5 and about 70 nanometers..., length 102 times the diameter, and an outer region of multiple essentially continuous layers of ordered carbon atoms and a distinct inner core...." Helping to create the initial excitement associated with carbon nanotubes were Iijima's 1991 discovery of multi-walled carbon nanotubes in the insoluble material of arc-burned graphite rods; and Mintmire, Dunlap, and White's independent prediction that if single-walled carbon nanotubes could be made, they would exhibit remarkable conducting properties. Nanotube research accelerated greatly following the independent discoveries by Iijima and Ichihashi at NEC and Bethune et al.
== Related problems and reformulations == The hypercycle concept has been continuously studied since its origin. Shortly after Eigen and Schuster published their main work regarding hypercycles, John Maynard Smith raised an objection that the catalytic support for the replication given to other molecules is altruistic. Therefore, it cannot be selected and maintained in a system. He also underlined hypercycle vulnerability to parasites, as they are favoured by selection. Later on, Josef Hofbauer and Karl Sigmund indicated that in reality, a hypercycle can maintain only fewer than five members. In agreement with Eigen and Schuster's principal analysis, they argued that systems with five or more species exhibit limited and unstable cyclic behaviour, because some species can die out due to stochastic events and break the positive feedback loop that sustains the hypercycle. The extinction of the hypercycle then follows. It was also emphasized that a hypercycle size of up to four is too small to maintain the amount of information sufficient to cross the information threshold. Several researchers proposed a solution to these problems by introducing space into the initial model either explicitly or in the form of a spatial segregation within compartments. Bresch et al. proposed a package model as a solution for the parasite problem. Later on, Szathmáry and Demeter proposed a stochastic corrector machine model. Both compartmentalized systems proved to be robust against parasites.
Charged analytes have a more complex interaction in the capillary because they exhibit electrophoretic mobility, engage in electrostatic interactions with the micelle, and participate in hydrophobic partitioning. The fraction of the sample in the aqueous phase,
Sources: en.wikipedia.org
=== Other toxicants === Carbon disulfide is a risk factor and has been identified in industrial worker case studies and has induced parkinsonism in mice. It is mainly used in the manufacture of viscose rayon and rubber. Carbon disulfide has been mixed with carbon tetrachloride for use in the fumigation of grain.
=== Prescription drug history === Antibiotics first arrived on the medical scene in 1932 thanks to Gerhard Domagk; and were coined the "wonder drugs". The introduction of the sulfa drugs led to the mortality rate from pneumonia in the U.S. to drop from 0.2% each year to 0.05% (i.e., 1⁄4 as much) by 1939. Antibiotics inhibit the growth or the metabolic activities of bacteria and other microorganisms by a chemical substance of microbial origin. Penicillin, introduced a few years later, provided a broader spectrum of activity compared to sulfa drugs and reduced side effects. Streptomycin, found in 1942, proved to be the first drug effective against the cause of tuberculosis and also came to be the best known of a long series of important antibiotics. A second generation of antibiotics was introduced in the 1940s: aureomycin and chloramphenicol. Aureomycin was the best known of the second generation. Lithium was discovered in the 19th century for nervous disorders and its possible mood-stabilizing or prophylactic effect; it was cheap and easily produced. As lithium fell out of favor in France, valpromide came into play. This antibiotic was the origin of the drug that eventually created the mood stabilizer category. Valpromide had distinct psychotrophic effects that were of benefit in both the treatment of acute manic states and in the maintenance treatment of manic depression illness. Psychotropics can either be sedative or stimulant; sedatives aim at damping down the extremes of behavior. Stimulants aim at restoring normality by increasing tone.
Synthesis during the formation of the universe is the only significant way naturally occurring deuterium has been created; it is destroyed in stellar fusion. Deuterium is thought to have played an important role in setting the number and ratios of the elements that were formed in the Big Bang. Combining thermodynamics and the changes brought about by cosmic expansion, one can calculate the fraction of protons and neutrons based on the temperature at the point that the universe cooled enough to allow formation of nuclei. This calculation indicates seven protons for every neutron at the beginning of nucleogenesis, a ratio that would remain stable even after nucleogenesis was over. This fraction was in favor of protons initially, primarily because the lower mass of the proton favored their production. As the Universe expanded, it cooled. Free neutrons and protons are less stable than helium nuclei, and the protons and neutrons had a strong energetic reason to form helium-4. However, forming helium-4 requires the intermediate step of forming deuterium. Through much of the few minutes after the Big Bang during which nucleosynthesis could have occurred, the temperature was high enough that the mean energy per particle was greater than the binding energy of weakly bound deuterium; therefore, any deuterium that was formed was immediately destroyed. This situation is known as the deuterium bottleneck. The bottleneck delayed formation of any helium-4 until the Universe became cool enough to form deuterium (at about a temperature equivalent to 100 keV).
=== Pharmacokinetics === Upon oral administration, bismuth subcitrate undergoes partial dissolution in the acidic gastric environment, with the majority of the dose localizing in the stomach. Although the most of the dose remains unabsorbed, a small portion enters into systemic circulation, and serum concentration reaches (Cmax at 20–30 min) 16–80 ng/mL - levels that exceed the minimum inhibitory concentration for H. pylori (1–8 μg/mL). Co-administration with proton pump inhibitors (PPI) such as omeprazole or H2-antagonists such as famotidine increases serum and tissue concentrations of bismuth, possibly due to greater solubility and less rapid precipitation in less acidic gastric juice. In the small intestine, unlike the stomach, bismuth subcitrate does not form stable binding layers or antimicrobial reservoirs. At the more alkaline pH, colloidal particles aggregate and precipitate without significant further dissolution or interaction with epithelial or microbial targets. There is no conclusive evidence for microbiological impact of bismuth in the small intestine when administered at therapeutic doses. Upon entry into the large intestine (colon), bismuth is exposed to an anaerobic, sulfur-rich environment maintained by the gut microbiota. Here, it undergoes microbial methylation and sulfide complexation, yielding species such as trimethylbismuth (TMBi) and insoluble bismuth sulfide (Bi2S3), which is responsible for the black coloration of stool during therapy.
Eating much faster than normal, perhaps in a short space of time Eating until feeling uncomfortably full Eating a large amount even when not hungry Subjective loss of control over how much or what is eaten Planning and allocating specific times for bingeing Eating alone or secretly Not being able to remember what was eaten after the binge Feelings of guilt, shame, or disgust following a food binge Body image disturbance In contrast to bulimia nervosa, binge eating episodes are not regularly followed by activities intended to compensate for the amount of food consumed, such as self-induced vomiting, laxative or enema misuse, or strenuous exercise. BED is characterized more by overeating than dietary restriction. Those with BED often have poor body image and frequently diet, but are unsuccessful due to the severity of their binge eating. Obesity is common in persons with BED, as are depression, low self-esteem, stress and boredom. Regarding cognitive abilities, individuals showing severe binge eating symptoms may experience small dysfunctions in executive functions. Those with BED are also at risk of non-alcoholic fatty liver disease, menstrual irregularities such as amenorrhea, and gastrointestinal problems such as acid reflux and heartburn.
Sources: en.wikipedia.org
它不是经典的内分泌激素，而是一种免疫调节肽。其作用主要通过局部免疫细胞间的信号传递实现，而非经血液循环作用于远隔器官。
天然胸腺素α1主要从胸腺组织提取，也可在脾脏和淋巴结中检出。目前研究和临床使用的多为化学合成版本，不再依赖动物组织。
胸腺素组分5是牛胸腺提取物的粗组分，包含多种肽。胸腺素α1是其中一种被纯化和表征的单一肽，具有明确的28个氨基酸序列。
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.