Everything below concerns 反相色谱. We keep the language plain, cite what the science says, and separate well-supported claims from open questions.
Last reviewed on 2025-10-28. Where a claim depends on a specific study, the study is described rather than over-claimed.
Reported pharmacological work centers on neurotrophic signaling, including changes in BDNF and NGF expression in hippocampal tissue in animal models. Human data come largely from studies conducted in Russia, and how well those results generalize to other populations remains an open question. Regulatory status differs sharply by jurisdiction: Semax is a registered prescription medicine in Russia, while it holds no approved marketing status in the United States or the European Union. Outside such jurisdictions it is generally handled as a research chemical, which affects both documentation and quality expectations.
Semax is a synthetic heptapeptide whose sequence is Met-Glu-His-Phe-Pro-Gly-Pro. It was developed as a fragment analog of adrenocorticotropic hormone, modeled specifically on the ACTH(4-10) region. The first four residues reproduce that fragment, while a Pro-Gly-Pro tripeptide is appended at the C-terminus. Work on the compound originated in Russia, where it entered clinical use as an intranasal preparation. Its sequence places it among short regulatory peptides studied for effects on the central nervous system rather than on the adrenal axis.
The C-terminal Pro-Gly-Pro extension is not incidental. Proline-rich tails are known to resist several common peptidases, and the published literature attributes the longer half-life of Semax, relative to unmodified ACTH fragments, to this feature. The modification also removes the melanocyte-stimulating and corticosteroidogenic activity that characterizes longer ACTH-derived sequences. Because the molecule is small and hydrophilic, it is typically formulated as an aqueous solution for intranasal or parenteral delivery. Acetylation or amidation at the termini appears in closely related research peptides and shifts the mass by a fixed increment.
纯度评估以反相高效液相色谱为主，通过主峰面积百分比给出粗略结果，再配合电喷雾质谱核对分子量。氨基酸分析可验证组成比例，手性色谱或毛细管电泳用于检查残基构型。常见杂质包括缺失序列的短肽、氧化产物与二聚体。由于多数市售品不附带完整检验报告，独立第三方检测常被用来核实标称值。
从分子层面看，Semax 是线性七肽，没有二硫键、糖基或脂链修饰，N 端为游离氨基，C 端为游离羧基。分子含组氨酸与谷氨酸侧链，因此在水和甲醇等极性溶剂中溶解良好，在非极性溶剂中溶解有限。计算分子量约为 814 Da，与其质子化离子的质荷比吻合，可用于质谱确认。
稳定性主要由水解与氧化两条路径支配。肽键在中性或弱酸性条件下相对稳定，遇到强碱或长时间高温则明显断裂；甲硫氨酸侧链容易被氧化成亚砜，使主峰前移并拉低实际含量。金属离子、光照和反复冻融会进一步促进降解或聚集。冻干粉在低温避光条件下可存放较长时间，配制后的水溶液通常需要冷藏并尽快用完。
| Property | Value | Notes |
|---|---|---|
| Molecular weight | ~813.9 Da (free heptapeptide) | N-acetylated form is about 42 Da heavier |
| Residue count | 7 (heptapeptide) | Four residues from ACTH(4-10), three added |
| Appearance | White to off-white powder | Usually supplied lyophilized |
| Solubility class | Freely soluble in water | Also dissolves in DMSO and polar organic solvents |
| Related parent fragment | ACTH(4-10) | Parent motif is Met-Glu-His-Phe |
该化合物于二十世纪八十年代在俄罗斯被开发，相关工作由俄罗斯科学院分子遗传学研究所的研究团队主导。开发目标并非复制 ACTH 的完整激素活性，而是寻找保留其神经作用方向、同时去除促肾上腺皮质激素释放效应的短肽片段。研究记录显示，这一方向促成了多个相关短肽的合成与筛选，而 Semax 是其中被研究最广泛的一个。当地文献常以 Семакс 这一名称指代它。
研究兴趣主要集中在神经营养因子相关的路径上，包括脑源性神经营养因子与神经生长因子的表达变化。部分实验报告称在特定条件下观察到这些因子的水平上升，但具体信号通路和剂量依赖关系仍未完全厘清。多数公开数据来自细胞模型和动物实验，人体对照研究数量有限。因此，该化合物的作用机制在文献中属于活跃讨论，而非已经确立的定论。
Semax 是一种人工合成的七肽，氨基酸序列为 Met-Glu-His-Phe-Pro-Gly-Pro，单字母缩写记作 MEHFPGP。它被归类为促肾上腺皮质激素片段 ACTH(4-10) 的结构类似物，但并不天然存在于生物体内。母体片段 ACTH(4-10) 的序列为 Met-Glu-His-Phe-Arg-Trp-Gly，Semax 替换了中间两个残基，并在羧基端延长了 Pro-Gly-Pro 三肽。这种延长被普遍认为能提升分子对肽酶的耐受性。
Published research has focused mainly on neurological and cognitive endpoints in animal models, with proposed mechanisms involving brain-derived neurotrophic factor and related signalling pathways. A substantial share of the human data originates from a limited number of research groups, and independent replication in other countries remains sparse. Regulatory status reflects that distribution: the peptide is registered as a medicine in Russia and appears in some neighbouring markets, while elsewhere it is handled as a research chemical without approved therapeutic labelling. Questions about dose-response relationships, long-term effects, and comparability across studies are still open.
Lyophilised powder is normally kept at -20 °C in a desiccated container, with some suppliers recommending -80 °C for long-term archival storage. Repeated freeze-thaw cycles are the most common cause of avoidable loss, so aliquoting before freezing reduces variability between working sessions. Dissolved peptide is far less stable than the dry solid and is usually prepared fresh or held briefly at 4 °C. Aqueous solutions support both hydrolysis of the backbone and oxidation of the N-terminal methionine, and these two routes dominate degradation under ordinary laboratory conditions.
Development of the compound took place in the Soviet Union during the 1980s, largely through peptide research groups affiliated with the Shemyakin-Ovchinnikov Institute and Moscow State University. Investigators screened fragments of adrenocorticotropic hormone for activity on the central nervous system while attempting to separate cognitive effects from hormonal ones. The shortened sequence was selected because it retained behavioral activity in animal models without stimulating corticosteroid release. Early publications described the molecule as an ACTH(4-10) analog.
Published research on this peptide originates mainly from Russian laboratories, and the wider international literature is comparatively thin. Studies have used rodent models of stroke, hypoxia, and memory tasks, with a smaller number of human trials reported. Reported outcomes include changes in attention and memory measures, along with effects on neurotrophic factor expression in some experiments. Small sample sizes, inconsistent dosing protocols, and limited independent replication are widely noted limitations, so the strength of the clinical evidence remains an open question.
Material sold for laboratory use varies widely in stated purity and documentation. A certificate of analysis should list the analytical method, the column and detector used, and the observed purity value. Independent verification by an outside laboratory is the practical way to confirm identity when documentation is absent or internally inconsistent. Regulatory status differs by country, and a product legal in one jurisdiction may be unapproved or controlled in another.
Identity and purity of semax are established with reversed-phase high-performance liquid chromatography coupled to ultraviolet detection, usually at 214 nanometres. Mass spectrometry, most often electrospray ionisation in positive mode, confirms the molecular mass and reveals truncated sequences. Amino acid analysis and peptide mapping after enzymatic digestion provide additional structural confirmation. Laboratories typically report purity as the percentage area of the main peak, a figure that does not capture isomeric or oxidised variants unless the method resolves them.
=== Analogues and derivatives === Analogues of 2C-B include 2C-I, 2C-C, DOB, 4C-B, 2C-B-FLY, and 25B-NBOMe, among others. DOB and 4C-B are α-alkyl derivatives of 2C-B, specifically the amphetamine (α-methyl) and phenylisobutylamine (α-ethyl) derivatives, respectively. β-Substituted derivatives of 2C-B such as BOB (β-methoxy-2C-B), BOH-2C-B (β-hydroxy-2C-B), βk-2C-B (β-keto-2C-B), and β-methyl-2C-B (BMB) have been described. βk-2C-B shows dramatically reduced potency and efficacy as a serotonin 5-HT2A receptor agonist compared to 2C-B. A variety of N-substituted derivatives of 2C-B have been tested, including N-methyl-2C-B, N,N-dimethyl-2C-B, N-ethyl-2C-B, and N-benzyl-2C-B. Most simple alkyl derivatives were considerably less potent than 2C-B, with N-ethyl-2C-B for instance having a 40 times lower affinity for the serotonin 5-HT2A receptor. The N-benzyl derivative however was found to have higher affinity than 2C-B itself, with N-(4-bromobenzyl)-2C-B binding even more tightly. This initial research did not include functional assays of activity, but later led to the development of potent substituted N-benzyl derivatives such as 25B-NBOMe, and 25B-NBOH. Another N-substituted derivative, 2C-B-AN, is an N-benzylphenethylamine-like prodrug of 2C-B. 2C-DB (6-bromo-2C-B) is a ring-substituted derivative of 2C-B. TWEETIO derivatives of 2C-B, in which one or both of the methoxy groups of 2C-B are extended to ethoxy groups, exist as well, such as 2CB-2-EtO.
== Career == McLain provides voices for many characters in several video games from Valve. Among them are GLaDOS, the primary antagonist of the Portal video game series (for which she won an AIAS Interactive Achievement Award for Outstanding Achievement in Character Performance), the announcer in Team Fortress 2, and the voice of the Combine Overwatch for the Half-Life series. McLain sang "Still Alive" and "Want You Gone", the ending credits songs to Portal and Portal 2, respectively, both of which were written by Jonathan Coulton. She also sang "Cara Mia Addio" at the end of Portal 2. In December 2011, McLain won the Spike Video Game Award in the category "Best Performance by a Human Female" for her voice acting as GLaDOS in Portal 2. In 2013, she lent her public support to gathering donations for the Kickstarter-funded LGBT gaming convention GaymerX. She later was a special guest at the convention in August 2013. In 2014, she portrayed Fairy Godmother in the online video series [Wish It Inc.]. In 2015, she portrayed Lisa Clarke in the gay independent film, Winning Dad. This film was also promoted on McLain's YouTube channel. McLain has played roles in many radio dramas on the radio program Imagination Theatre. In 2021, McLain provided the voice of GLaDOS non-canonically, singing a verse in The Chalkeaters’ song "Count to Three" as a cameo.
If the reaction is more complicated, then the output is not uniquely determined by the RTD. It also depends on the degree of micromixing, the mixing between molecules that entered at different times. If there is no mixing, the system is said to be completely segregated, and the output can be given in the form
Public awareness of food preservatives is uneven. Americans have a perception that food-borne illnesses happen more often in other countries. This may be true, but the occurrence of illnesses, hospitalizations, and deaths are still high. It is estimated by the Centers for Disease Control (CDC) that each year there are 76 million illnesses, 325,000 hospitalizations, and 5,000 deaths linked to food-borne illness. Food suppliers are facing difficulties with regards to the safety and quality of their products as a result of the rising demand for ready-to-eat fresh food products. Artificial preservatives meet some of these challenges by preserving freshness for longer periods of time, but these preservatives can cause negative side-effects as well.
Anahuasca (ayahuasca analogue or variants). A term usually used to refer to the ayahuasca produced with other plant species as sources of DMT (e.g., Mimosa hostilis) or β-carbolines (e.g., Peganum harmala). Pharmahuasca (pharmaceutical ayahuasca). This indicates the pills produced from freebase DMT, synthetic harmaline, MAOI medications (such as moclobemide) and other isolated or purified compounds or extracts.
Sources: en.wikipedia.org
Plantain plantations are vulnerable to destruction by hurricanes, because Musa spp. do not withstand high winds well. An average plantain provides about 920 kilojoules (220 kilocalories) of food energy and is a good source of potassium and dietary fiber. The sap from the fruit peel, as well as the entire plant, can stain clothing and hands, and can be difficult to remove.
Quercetin: Quercetin (a flavonoid found in vegan food) supplements, has been suggested to treat baldness. A 2012 study demonstrated that alopecia areata could be used to prevent ant treated with quercetin in mice. Quercetin is found in onions primarily in the peel and the first scaly leaf but not in the flesh. Onion bulb size or weight does not appear to be affected by quercetin concentration. A 2020 study demonstrated that quercitrin stimulated hair shaft growth in cultured human hair follicles. Volatile compounds responsible for pungency and tearing in onions when they are cut (e.g. syn-propanethial S-oxide gas). However, no formal studies have been conducted to evaluate if these compounds promote hair growth or if they help other compounds to penetrate the skin to form hair follicles. To use the volatile compounds: Onions must be extracted and applied topically quickly before the volatile compounds evaporate. The extract will cause tearing eyes, but it can be prevented with a shower cap, or a pair of swimming goggles. To discard the volatile compounds: The onion juice is extracted and stored for a short while to evaporate the volatile compounds. The extract will not cause tearing eyes. Also, both genetically modified, and plant breed onions have been produced with significantly reduced levels of tear-inducing lachrymatory factor.
=== Hair transplantation === All the current hair transplantation techniques utilize the patient's existing hair. The aim of the surgical procedure is to use such hair as efficiently as possible. The right candidates for this type of surgery are individuals who still have healthy hair on the sides and the back of the head in order that hair for the transplant may be harvested from those areas. Different techniques are utilized in order to obtain the desired cosmetic results; factors considered may include hair color, texture, curliness, etc. The most utilized technique is the one known as micro grafting because it produces naturalistic results. It is akin to follicular unit extraction, although less advanced. A knife with multiple blades is used to remove tissue from donor areas. The removed tissue is then fragmented into smaller chunks under direct vision inspection (i.e., without a microscope).
== See also == Control of water pollution – Contamination of water bodies Clean Water Act – 1972 U.S. federal law regulating water pollution Peak water – Concept on the quality and availability of freshwater resources Pulsed-power water treatment – Using electro-magnetic fields on cooling water Solar water disinfection – Portable water purification powered by sunlight Raw water#Treatment – Untreated water found in a natural environment Water purification – Process of removing impurities from water Water quality – Assessment against standards for use Water softening – Removing positive ions from hard water Water supply – Provision of water by public utilities, commercial organisations or others
Sources: en.wikipedia.org
The sequence is Met-Glu-His-Phe-Pro-Gly-Pro, a seven-residue peptide. The first four residues correspond to the ACTH(4-10) fragment, and Pro-Gly-Pro is added at the C-terminus. N-acetylated versions also appear in the literature and differ in mass.
Semax is a synthetic analog of the ACTH(4-10) fragment rather than a copy of the full hormone. Truncation plus the added tail removes the steroidogenic portion of ACTH. That distinction explains why it is studied for nervous-system effects instead of adrenal stimulation.
It is registered as a prescription product in Russia and has been used there clinically, chiefly by the intranasal route. No approval exists in the United States or the European Union. Availability elsewhere typically falls under research-chemical distribution, with varying purity documentation.
电喷雾或基质辅助激光解吸电离质谱是常用手段，测得的质子化离子质荷比可换算为分子量。结果与理论值落在合理误差内，才支持结构一致的判断。