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 2025-10-23 and is reviewed periodically as new material appears.
Scientific literature on semax is unevenly distributed. A substantial share of published work originates from a small number of laboratories in Russia, while independent replication elsewhere is limited. Human data consist mostly of small trials with short follow-up, and several reported outcomes rely on subjective rating scales. Questions about how much intact peptide reaches the central nervous system after nasal administration, and how long it persists there, are still unresolved. The compound is best described as an active research subject rather than a settled pharmacological agent.
Semax is a synthetic heptapeptide with the sequence Met-Glu-His-Phe-Pro-Gly-Pro. It was derived from the ACTH(4-10) fragment, a short segment of adrenocorticotropic hormone that lacks the hormonal activity associated with the full-length peptide. Researchers at the Institute of Molecular Genetics in Moscow developed the compound during the 1980s. It has been registered as a pharmaceutical product in Russia and several neighbouring countries, where it is supplied as a nasal solution, and it is also sold internationally as a research chemical.
常规纯度与身份确认依赖反相高效液相色谱，并辅以质谱测定分子量。氨基酸组成分析可用于验证序列构成，肽图分析则能进一步定位修饰或降解产物。杂质谱通常关注缺失序列肽、截短片段和氧化产物。不同方法的检出限并不相同，因此各实验室报告的纯度数值不宜直接横向比较。
多数实验室与市售的 Semax 以冻干粉形式提供。冻干粉通常建议保存在 -20 °C 或更低温度下，同时避免光照与反复升温。短期运输有时采用冷藏条件，但长期保存仍以冷冻为主。分包操作应尽量减少开盖次数，以降低吸湿和微生物污染的风险。开封后若未一次用完，建议在干燥环境中密封并尽快放回低温储存。
溶液状态的稳定性明显低于冻干粉。肽类在水溶液中可能经历水解、氧化与聚集，其中甲硫氨酸和天冬酰胺等残基常是敏感位点。Semax 含有甲硫氨酸，因此氧化风险相对突出。工作液一般主张现配现用，或冷藏并在数日内用尽。缓冲液种类、pH 和离子强度都会影响降解速率，而关于最佳条件的公开数据并不统一。
| Property | Value | Notes |
|---|---|---|
| Molecular formula | C37H51N9O10S | Calculated for the free peptide |
| Molar mass | 813.9 g/mol | Anhydrous free base |
| Peptide class | Synthetic heptapeptide | ACTH(4-10) analogue |
| Parent fragment | ACTH(4-10) | Adrenocorticotropic hormone segment |
| Developmental origin | Institute of Molecular Genetics, Moscow | Work began in the 1980s |
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。
Quality documentation for research-grade peptide usually includes a certificate of analysis stating purity, identity, and residual counterion content. Batch-to-batch variation in purity and salt form is a recognized issue, and comparisons across suppliers require attention to the exact counterion, for example acetate versus trifluoroacetate. Sequence verification by tandem mass spectrometry provides stronger evidence than a single mass measurement. For any study reporting biological results, the analytical method and the measured purity should be stated explicitly. Independent verification of supplier claims is considered good practice.
Semax is supplied as a lyophilized powder that appears white to off-white. It dissolves readily in water, phosphate-buffered saline, and other aqueous media, which simplifies preparation of working solutions for laboratory use. The nasal products registered in Russia are dilute aqueous solutions, typically around 0.1 percent peptide by weight. Organic solvents are rarely necessary and can complicate handling. Because the peptide is hygroscopic, weighing should be performed quickly and with minimal exposure to ambient humidity.
Clinical evidence consists largely of small trials with modest sample sizes, often without independent replication. Reported endpoints include cognitive scores, recovery after stroke, and visual function, but study designs vary widely and few trials meet contemporary reporting standards. Systematic reviewers have noted a high risk of bias in several of these reports. No large multicenter trial conducted outside Russia has been published. The compound is therefore best described as investigational in most jurisdictions, with its clinical role still unresolved.
Semax is a synthetic heptapeptide with the sequence Met-Glu-His-Phe-Pro-Gly-Pro. Its chain combines the first seven residues of corticotropin with a C-terminal proline-glycine-proline extension, a modification intended to slow enzymatic breakdown. The free peptide has a molecular mass near 813.9 daltons. It belongs to the class of ACTH-derived fragments studied for central nervous system activity rather than for adrenal steroid stimulation. This structural relationship to a natural hormone fragment is the usual starting point for describing the compound in the literature.
=== Approval rate === While over 150 cerebroprotectants have been tested in clinical trials, as of 2022 only the above two cerebroprotectants are approved, though several clinical trials for other drugs are ongoing. The approval rate has been less than 2%, which is low compared to the overall approval rate of all drugs brought into clinical trials in all disease areas from 2011 to 2022 which was 7.9%. It is also much lower than the relatively high success rate for devices to treat acute ischemic stroke, as there have been at least 5 different clot removal devices approved since 2015.
=== Psychological and behavioral === Psychological and behavioral therapies are used across all forms of addiction, both alone and together with medication; commonly used approaches include CBT, motivational interviewing, contingency management (which provides tangible rewards for verified abstinence), and twelve-step facilitation. For stimulant use disorder, contingency management (particularly when combined with a community reinforcement approach) has the strongest supporting evidence among psychosocial treatments. For alcohol use disorder, structured twelve-step facilitation programs that encourage participation in Alcoholics Anonymous are at least as effective as other established therapies such as CBT for sustaining abstinence and may lower health-care costs. The creative arts therapies, including art therapy, music therapy, drama and dance, are sometimes offered alongside conventional treatment, and artwork produced during treatment has been used informally to aid assessment and track progress. A 2018 systematic review found insufficient evidence that visual art, drama, or dance and movement therapies reduce substance misuse, though music therapy showed some promise in preparing people to engage with treatment. Proposed benefits include providing a non-verbal outlet for difficult emotions and strengthening engagement in treatment.
=== Clinical outcomes === In clinical trials the outcome of different types of treatment is compared to identify if a compound or regimen is favourable for the patient. The choice of treatment in the conditioning therapy can have a profound impact on progression-free survival (PNS), overall survival (OS), relapse incidence (RI) and non-relapse mortality (NRM). The studies mentioned summarize key findings comparing various conditioning regimens. Studies on conditioning regimens for hematopoietic cell transplant in primary central nervous system lymphoma (PCNSL) have shown that thiotepa based therapies thiotepa/busulfan/cyclophosphamide (TBC) and thiotepa/carmustine (TT-BCNU) improve progression-free survival of PCNSL compared to traditional therapies carmustine/etoposide/cytarabine/melphalan (BEAM). Research also suggests that in BEAM if carmustine is exchanged for thiotepa no statistical difference was found in PFS, OS and RI. Furthermore, the capacity of thiotepa to pass the blood-brain barrier may allow optimizing the therapy for patients with Central Nervous System involvement of increased CNS relapse risk. Another study compared total body irradiation (TBI) and thiotepa, busulfan and cyclophosphamide/fludarabine (TTB) as a conditioning regimen of patients with acute lymphoblastic leukemia undergoing allogenic hematopoietic stem cell transplantation. No statistical difference was found in the overall survival but the RI was higher in the TBI regimen but the NRM was lower with TTB suggesting that TBB might be a viable alternative to TBI.
=== Motion preservation and facet arthroplasty === Independent reviews place TOPS within a broader group of posterior motion-preserving technologies developed to address the trade-off between decompression, stability, and retained segmental motion. Unlike lumbar disc replacement, which principally addresses disc pathology, facet arthroplasty is intended to restore stability after decompression in patients whose disease involves the posterior spinal elements, including the facet joints. Reviews identify preservation of motion and the potential to reduce adjacent-segment disease as key proposed advantages, while emphasizing the importance of patient selection and the need for continued long-term data on implant durability, revision, and adjacent-segment outcomes.
== Leidenfrost temperature and surface tension effects == The Leidenfrost temperature is the property of a given set of solid–liquid pair. The temperature of the solid surface beyond which the liquid undergoes the Leidenfrost phenomenon is termed the Leidenfrost temperature. Calculation of the Leidenfrost temperature involves the calculation of the minimum film boiling temperature of a fluid. Berenson obtained a relation for the minimum film boiling temperature from minimum heat flux arguments. While the equation for the minimum film boiling temperature, which can be found in the reference above, is quite complex, the features of it can be understood from a physical perspective. One critical parameter to consider is the surface tension. The proportional relationship between the minimum film boiling temperature and surface tension is to be expected, since fluids with higher surface tension need higher quantities of heat flux for the onset of nucleate boiling. Since film boiling occurs after nucleate boiling, the minimum temperature for film boiling should have a proportional dependence on the surface tension. Henry developed a model for the Leidenfrost phenomenon which includes transient wetting and microlayer evaporation. Since the Leidenfrost phenomenon is a special case of film boiling, the Leidenfrost temperature is related to the minimum film boiling temperature via a relation which factors in the properties of the solid being used.
Sources: en.wikipedia.org
On November 2, 2007, Alice in Chains performed a four-song set at Benaroya Hall in Seattle for Matt Messina and the Symphony Guild's 10th anniversary benefit concert for the Seattle Children's Hospital & Regional Medical Center. In addition to the band's original material, they also played a cover of Led Zeppelin's "Kashmir" while backed by over 200 musicians, including the Northwest Symphony Orchestra and the Northwest Girlchoir.
For some substances, such as carbon and arsenic, sublimation from solid state is much more achievable than evaporation from liquid state and it is difficult to obtain them as liquids. This is because the pressure of their triple point in its phase diagram (which corresponds to the lowest pressure at which the substance can exist as a liquid) is very high. Sublimation is caused by the absorption of heat which provides enough energy for some molecules to overcome the attractive forces of their neighbors and escape into the vapor phase. Since the process requires additional energy, sublimation is an endothermic change. The enthalpy of sublimation (also called heat of sublimation) can be calculated by adding the enthalpy of fusion and the enthalpy of vaporization.
A defining characteristic of Wagyu beef is its abundant, finely distributed intramuscular fat, referred to in Japanese as sashi. Among the four Wagyu breeds, this high degree of marbling is especially characteristic of Japanese Black cattle, whose beef has been reported to contain more than 30% intramuscular fat. The degree of marbling is influenced by genetic, physiological, and feeding factors, although the mechanisms that enable Japanese Black cattle to produce such highly marbled beef are not yet fully understood. Pronounced marbling is also found in Mishima cattle. Mishima and Kuchinoshima cattle—the latter producing lean meat—are the two native Japanese cattle populations considered to have remained free from European genetic influence. The occurrence of pronounced marbling in Mishima cattle therefore suggests that at least some native Japanese cattle already possessed a genetic capacity for marbling before European crossbreeding was used to develop the modern Wagyu breeds. Among Japanese Black cattle, the Tajima strain is less prone to depositing subcutaneous and intermuscular fat but readily develops intramuscular marbling. The fat in Japanese Black beef contains a high proportion of monounsaturated fatty acids, particularly oleic acid. This composition gives the fat a relatively low melting point and soft consistency, contributing to the characteristic melt-in-the-mouth texture and rich juiciness of highly marbled Wagyu beef. Beef from Japanese Black cattle also develops a distinctive rich, sweet aroma during cooking, commonly called "Wagyu beef aroma".
== Family and personal life == Dan Ariely was born to Yoram and Dafna Ariely in New York City while his father was studying for an MBA at Columbia University. He has two younger sisters. The family emigrated to Israel when he was three years old. He grew up in Ramat Hasharon. In his senior year of high school, Ariely was active in Hanoar Haoved Vehalomed, an Israeli youth movement affiliated with the Labor Zionist movement. While he was preparing a ktovet esh (fire inscription) for a traditional nighttime ceremony, the flammable materials he was mixing exploded, causing third-degree burns to over 70 percent of his body. In his writings entitled "Painful Lessons", Ariely described his hospitalization and treatments, detailing how that experience led to his research on "how to better deliver painful and unavoidable treatments to patients". Ariely was previously married to Sumedha (Sumi) Gupta in 1998; they have two children. After a second manuscript of his was retracted for containing fabricated data, it was reported that Ariely is seeking political office under the banner of the Pirate Party of Israel.
Sources: en.wikipedia.org
== S == safe sex – safer sex – salmonella – salvage therapy – SAMHSA – sarcoma – seborrheic dermatitis – secondary prophylaxis – sepsis – seroconversion – serologic test – seroprevalence – serosorting – serostatus – serum – serum glutamic oxaloacetic transaminase (SGOT) – serum glutamic pyruvate transaminase (SGPT) – sexually transmitted disease (STD) – shingles – SHIV – side effects – simian immunodeficiency virus (SIV) – sinusitis – social integration SIT – SIV – Special Projects of National Significance (SPNS) – spinal tap – spleen – splenomegaly – sputum analysis – standard of care – staphylococcus – STD – stem cells (FDCs) – steroid – Stevens–Johnson syndrome – STI – stomatitis – strain – stratification – structured intermittent therapy (SIT) – structured treatment interruption (STI) – study endpoint – subarachnoid space – subclinical infection – subcutaneous (SQ) – Substance Abuse and Mental Health Services Administration (SAMHSA) – subunit HIV vaccine – sulfa drug – sulfonamides – superantigen – suppressor T cell – surrogate marker – surveillance – susceptible – symptoms – syncytium – syndrome – synergy – synergistic – synthesis – syphilis – systemic
Heart block, second or third degree (without pacemaker) Severe sinoatrial block (without pacemaker) Serious adverse drug reaction to lidocaine or amide local anesthetics Hypersensitivity to corn and corn-related products (corn-derived dextrose is used in the mixed injections) Concurrent treatment with quinidine, flecainide, disopyramide, procainamide (class I antiarrhythmic agents) Prior use of amiodarone hydrochloride Adams–Stokes syndrome Wolff–Parkinson–White syndrome Lidocaine viscous is not recommended by the FDA to treat teething pain in children and infants. Exercise caution in people with any of these:
3,4-dehydro-thiomorpholine-3-carboxylate + NAD(P)H + H+ The two substrates of this enzyme are thiomorpholine 3-carboxylate and oxidised nicotinamide adenine dinucleotide (NAD+). Its products are 3,4-dehydro-thiomorpholine-3-carboxylate, reduced NADH, and a proton. Nicotinamide adenine dinucleotide phosphate can be used as an alternative cofactor. This enzyme belongs to the family of oxidoreductases, specifically those acting on the CH-NH group of donors with NAD+ or NADP+ as acceptor. The systematic name of this enzyme class is thiomorpholine-3-carboxylate:NAD(P)+ 5,6-oxidoreductase. Other names in common use include ketimine reductase, and ketimine-reducing enzyme. CRYM, a taxon-specific crystallin protein that also binds thyroid hormones has thiomorpholine-carboxylate dehydrogenase activity.
Schleswig-Holstein combines Danish, Frisian, and German aspects of culture. The castles and manors in the countryside are the best example for this tradition; some dishes like Rødgrød (German: Rote Grütze, literal English "red grits" or "red groats") are also shared, as well as surnames such as Hansen.
Beyond Meat Burger: Beyond Meat patty, mustard, ketchup, mayonnaise, red onion, pickles, lettuce, tomato, sesame seed bun, A&W seasoning Beyond Meat Sausage N' Egger: Beyond Meat sausage patty, margarine, egg, cheddar cheese, English muffin
Sources: en.wikipedia.org
Semax is based on the ACTH(4-10) fragment, a seven-amino-acid segment of adrenocorticotropic hormone. The synthetic peptide retains the core sequence while removing regions associated with endocrine activity. This modification is intended to isolate effects on the nervous system.
It is registered for clinical use in Russia and a few other countries, typically as a nasal drop formulation. It does not hold approval from the United States Food and Drug Administration or the European Medicines Agency. Outside those markets it is generally handled as a research chemical.
The compound was developed in Moscow and the earliest studies were conducted there, so the primary literature is largely in Russian-language journals. Translation and indexing have been incomplete, which limits access for outside researchers. Independent groups have since published some work, but the total volume remains modest.
一般不建议常温长期保存。多数说明指向 -20 °C 冷冻避光。常温运输通常被视为短期可接受，但会加快降解风险。