This is a working overview of ACTH 片段, written for readers who want more than a one-paragraph summary but less than a textbook.
Reviewed 2026-06-01. Anything still debated is marked as such rather than presented as settled.
Semax 是人工设计的七肽，序列为 Met-Glu-His-Phe-Pro-Gly-Pro，骨架取自促肾上腺皮质激素片段 ACTH(4-10)。它于二十世纪八十年代在苏联的分子遗传学研究机构内合成。设计目标是保留该片段与注意力和记忆相关的活性，同时剔除促皮质激素释放等内分泌作用。此后俄罗斯将其登记为药品并进入临床使用。
当时的短肽研究普遍关注能否穿越血脑屏障、在低剂量下产生中枢效应，Semax 属于这一路线。鼻内给药是其主要使用方式，俄语文献报道的适应症涵盖缺血性卒中、短暂性脑缺血发作、认知功能减退以及视神经病变。这些研究大多发表在当地期刊上，样本规模与终点设置同西方试验惯例存在差异，国际同行对其临床证据的强度看法不一。
各国监管态度分化明显。俄罗斯按处方药管理，部分东欧国家留有使用记录；欧盟与美国未批准其作为药物上市，市面流通品通常标注为研究用化学品。身份差异意味着标示含量、纯度与无菌性缺少统一核查。体育领域还牵涉反兴奋剂名录，跨境携带则受目的地药品法规约束。
Identity and purity of Semax are established mainly by reversed-phase high-performance liquid chromatography coupled with mass spectrometry. The chromatographic trace gives a purity estimate as a percentage of total peak area, while electrospray or matrix-assisted laser desorption ionization confirms the molecular mass against the calculated value. Amino acid analysis and sequence-specific fragmentation provide further confirmation when a supplier's chain of custody is unclear. Vendors frequently quote a purity figure without stating the detection wavelength or the integration method, which limits how far one number can be compared with another.
Stability depends heavily on physical state. Lyophilized powder held dry, cold and dark retains its content over long periods, whereas dissolved peptide begins to change within days at room temperature. The most cited degradation route is oxidation of the methionine residue, which converts the peptide to a sulfoxide form that elutes differently on chromatography. Hydrolysis of amide bonds and adsorption onto container walls contribute smaller losses. Buffers that exclude oxygen from the headspace slow the oxidation pathway, but no single condition prevents all change indefinitely.
| Property | Value | Notes |
|---|---|---|
| 结构类别 | 线性合成七肽 | 无环化结构，不含二硫键 |
| 氨基酸序列 | Met-Glu-His-Phe-Pro-Gly-Pro | N 端为甲硫氨酸 |
| 分子量 | 约 814 Da | 游离碱形式的计算值 |
| 外观 | 白色至类白色粉末 | 具吸湿性 |
| 溶解性 | 易溶于水 | 亦可溶于甲醇等极性溶剂 |
Semax is a synthetic heptapeptide developed in the Soviet Union during the 1980s by researchers at the Institute of Molecular Genetics in Moscow. It was designed as a truncated analog of adrenocorticotropic hormone, retaining only the fragment spanning residues four through ten. Investigators sought a peptide that would preserve the cognitive effects associated with ACTH while eliminating the hormonal stimulation of the adrenal cortex. The compound entered clinical use in Russia during the following decade.
Russian regulatory authorities approved the peptide for nasal administration, and it remains listed in the national pharmacopoeia under several trade names. Documented indications include acute ischemic stroke, transient ischemic attacks, traumatic brain injury, and certain ophthalmological and neurological conditions. Physicians also prescribe it for cognitive complaints in older patients, although the evidence base for that use is thinner. Outside Russia and a few neighboring states, the substance is not an approved medicine and is sold instead as a research chemical.
Semax is normally supplied as a lyophilized powder, and that form is the most stable. Suppliers commonly recommend storage at -20 °C in a desiccated container protected from light, with short-term handling at room temperature limited to weighing and transfer. Powder that has absorbed moisture degrades faster, so vials should be warmed to ambient temperature before opening to prevent condensation on the contents. Hygroscopic behavior is typical of short hydrophilic peptides, and humidity control matters more than temperature alone for long-term retention.
Once dissolved, the peptide is considerably less stable than the solid. Aqueous solutions are usually prepared at neutral to slightly acidic pH, filtered, and divided into single-use aliquots before freezing. Repeated freeze-thaw cycles are a common cause of avoidable loss and are best prevented by never refreezing a thawed aliquot. Adsorption to plastic and glass surfaces can lower the measured concentration of dilute solutions, particularly below roughly 0.1 mg/mL. Buffer choice, salt content, and container material all influence how much peptide remains detectable after storage.
Semax is a synthetic heptapeptide with the sequence Met-Glu-His-Phe-Pro-Gly-Pro. It is described in the literature as an analogue of the ACTH(4–10) fragment, a short N-terminal portion of adrenocorticotropic hormone that retains some neurotropic activity without the full hormonal effects of the parent peptide. The molecule carries a methionine residue at the N-terminus and two proline residues near the C-terminus, features that shape both its interactions with receptor systems and its chemical stability. The free peptide corresponds to the formula C37H51N9O10S and a molecular mass near 813.9 Da.
The compound was developed in the 1980s at the Institute of Molecular Genetics in Moscow, where it emerged from research on short ACTH fragments and their effects on the central nervous system. Russian pharmaceutical listings describe it as a nootropic and neuroprotective agent, most often formulated as nasal drops. It is not a marketed medicine in the United States or the European Union, and no pharmacopoeial monograph covers it. Consequently, most published clinical experience with the substance originates from a small number of research centres, mainly in Russia and neighbouring countries.
Israel: Trump's plan was met with support in Israel with prime minister Benjamin Netanyahu saying that he was committed to the realization of the plan, rejecting the Palestinian Authority's or Hamas' governance of Gaza. Trump's proposal to resettle Palestinians from Gaza was supported by Netanyahu, Israeli Defense Minister Israel Katz, Israeli opposition leader Yair Lapid, and the majority of the Israeli public. Jordan: King Abdullah II of Jordan rejected President Trump's proposal for Jordan to absorb Palestinians living in Gaza. There are already more than 2 million Palestinian refugees in Jordan who fled due to the Arab–Israeli wars. Egypt: Egypt rejected American plans to annex Gaza and did not agree to take into Egypt displaced Palestinians. Instead, the Egyptian government responded by proposing a counter-offer of Egypt-led reconstruction of the strip. Egypt also signalled that the ethnic cleansing of Gaza would lead to the end of the Egypt–Israel peace treaty. Syria: Syrian president Ahmed al-Sharaa criticized Trump's plan, calling it a "serious crime that will ultimately fail." In an interview with The Rest Is Politics, al-Sharaa claimed that "no power can drive people from their land" and that "over 80 years of this conflict, all attempts to displace [Palestinians] have failed; those who left have regretted their decision. The Palestinian lesson that every generation has learned is the importance of holding on to their land." Turkey: Turkish president Erdogan rejected Trump's plan, highlighting that it would be a major threat to world peace.
2 Fe2O3 + 3 C → 4 Fe + 3 CO2 The flux removes silicaceous minerals in the ore, which would otherwise clog the furnace: The heat of the furnace decomposes the carbonates to calcium oxide, which reacts with any excess silica to form a slag composed of calcium silicate CaSiO3 or other products. At the furnace's temperature, the metal and the slag are both molten. They collect at the bottom as two immiscible liquid layers (with the slag on top), that are then easily separated. The slag can be used as a material in road construction or to improve mineral-poor soils for agriculture. Steelmaking thus remains one of the largest industrial contributors of CO2 emissions in the world.
The 1886 Jaffé reaction, in which creatinine is treated with an alkaline picrate solution to yield a red complex, is still the basis of most commonly used methods for measuring creatinine. This reaction is nonspecific and subject to interference from many noncreatinine chromogens, including acetone, acetoacetate, pyruvate, ascorbic acid, glucose, cephalosporins, barbiturates, and protein. It is also sensitive to pH and temperature changes. One or another of the many modifications designed to nullify these sources of error is used in most clinical laboratories today. For example, the recent kinetic-rate modification, which isolates the brief time interval during which only true creatinine contributes to total color formation, is the basis of the Astra modular system. More specific, non-Jaffé assays have also been developed. One of these, an automated dry-slide enzymatic method, measures ammonia generated when creatinine is hydrolyzed by creatinine iminohydrolase. Its simplicity, precision, and speed highly recommend it for routine use in the clinical laboratory. Only 5-fluorocytosine interferes significantly with the test. Creatinine must be determined in plasma or serum and not whole blood because erythrocytes contain considerable amounts of noncreatinine chromogens. To minimize the conversion of creatine to creatinine, specimens must be as fresh as possible and maintained at pH 7 during storage. The amount of urea produced varies with substrate delivery to the liver and the adequacy of liver function.
Sources: en.wikipedia.org
BCN, also known as bicyclo[6.1.0]non-4-yne, is a copper-free click chemistry probe that enables highly efficient and completely orthogonal bioconjugation to complex macromolecules including peptides, nucleic acids and proteins, including monoclonal antibodies. The most recent and powerful application of this technology has been in the field of antibody-drug conjugates which results in targeted cancer therapeutics that have an improved therapeutic index, meaning they are more effective and better tolerated. BCN is well-suited for aqueous bioconjugations due to its high reactivity with its azide counterpart and its high hydrophilicity, relative to other metal-free click chemistry probes.
Colin Stagg has been through a version of justice, albeit truncated, and he has been found not guilty. But I wonder whether he can actually say hand on heart that he believes people will meet him in the street and believe that. I do not believe the system served anybody that particular day. After Stagg's acquittal, Pedder took early retirement from the police. He later faced corruption charges, but the case was thrown out by the judge in a pre-trial hearing on the grounds of insufficient evidence.
== History of ITC == The history of ITC can be traced back to the 1930s when isothermal calorimetry was used to study chemical reactions. In 1965 Christensen and Izatt introduced titration calorimetry as a method for simultaneously determining the equilibrium constant and enthalpy. The ITC technique was then developed by H. D. Johnston in 1968 as a part of his Ph.D. dissertation at Brigham Young University, and was considered niche until introduced commercially by MicroCal Inc. in 1988. In 1978, Beaudette and Langerman conducted one of the earliest calorimetric binding studies using a small volume isoperibol titration calorimeter and a decade later, in 1989, Wiseman, Williston, Brandts, and Lin demonstrated its application in biological systems, marking the beginning of titration calorimetry as a valuable tool for studying biological equilibria. Originally, ITC was most often used to study the binding of small molecules (such as medicinal compounds) to larger macromolecules (proteins, DNA etc.) in a label-free environment. Its application has now broadened, aided by modern improvements, making it possible to measure the heat effects as small as 0.1 μcal (0.4 μJ) and determine the binding constants (K) as high as 108–109 M−1.
Sources: en.wikipedia.org
=== Presymbiosis === To form an ectomycorrhizal connection, the fungal hyphae must first grow towards the plant's roots. Then they must envelope and penetrate the root cap cells and infect them, allowing the symbiotic Hartig net and associated structures to form. Both partners (plant and fungus) must follow a precise sequence of gene expression for this to be successful. There is evidence that communication between the partners in the early stage of ectomycorrhiza occurs in some cases via volatile organic compounds produced only during the interaction phase, and that genes involved in secretory, apical growth, and infection processes show changes in expression early in the pre-contact phase. Thus, a complex set of molecular changes appears to take place even before the fungus and host plant make contact. The plant hosts release metabolites into the rhizosphere that can trigger basidiospore germination, growth of hyphae towards the root, and the early steps of EcM formation. These include flavonoids, diterpenes, cytokinins, hormones and other nutrients. Some host-released metabolites have been shown to stimulate fungal growth in Pisolithus, modify the branching angle of hyphae, and cause other changes in the fungus. Some fungal genes appear to be expressed before plant contact, suggesting that signals in the soil may induce important fungal genes at a distance from the plant.
Since the 1948 Palestinian expulsion and flight, Palestinian refugees have had a presence in Southern Lebanon as numerous refugee camps were established, which brought many Palestinian factions into south Lebanon, with it being often used as a center to launch rockets into northern Israel. The Palestine Liberation Organization was based in Lebanon after being expelled from Jordan by King Hussein in July 1971. After they were involved in an insurgency in Southern Lebanon, until they were expelled to Tunis after the 1982 Lebanon War.
Sedimentation equilibrium experiments reports the molar mass of analytes and their chemical equilibrium constants. The rotor speed is adjusted such that a steady-state concentration profile c(r) of the sample in the cell is formed, where sedimentation and diffusion cancel out each other. Ultracentrifuge Gas centrifuge Theodor Svedberg Differential centrifugation Buoyant density ultracentrifugation Zippe-type centrifuge Reversible Associations in Structural and Molecular Biology (RASMB -an Analytical Ultracentrifugation Forum) Analytical Ultracentrifugation as a Contemporary Biomolecular Research Tool. Archived 2002-08-04 at the Wayback Machine Gilbert-Jenkins theory Archived 2007-05-01 at the Wayback Machine Report on an ultracentrifuge explosion.
Sources: en.wikipedia.org
不存在。它是依据 ACTH 的一段序列人工设计的分子，天然蛋白质中找不到与之完全相同的七肽。名称属于研究代号，而非天然物质名。
Semax 对应 ACTH 第 4 至第 10 位的片段，并在两端做了替换与延长，使其不再具备促肾上腺皮质激素的典型内分泌活性。这一改动同时改变了它在体内的稳定性与分布特征。
俄罗斯将其列为处方药物，需要医生开具处方。多数其他国家把它当作研究化合物，不能作为药品销售或宣称疗效。具体合法性取决于当地法规。
Suppliers normally quote a percentage of total chromatographic peak area, most often from reversed-phase HPLC. That figure says nothing about what the remaining percentage contains, and it depends on the detection wavelength used. A mass spectrometry result is a separate and stronger check on identity.