Everything below concerns lyophilized powder. We keep the language plain, cite what the science says, and separate well-supported claims from open questions.
Last reviewed on 2026-03-20. Where a claim depends on a specific study, the study is described rather than over-claimed.
Semax is a synthetic heptapeptide with the sequence Met-Glu-His-Phe-Pro-Gly-Pro. Its design combines the ACTH(4-7) core fragment with a C-terminal Pro-Gly-Pro extension, a modification intended to improve stability and prolong activity. The molecule is hydrophilic, carries no lipid chains or glycosylation, and has a theoretical mass just over 810 daltons in its free form. All seven residues are proteinogenic amino acids, so no non-natural building blocks appear in the backbone. A free N-terminal methionine and C-terminal proline define the unmodified parent peptide.
The compound was developed during the 1980s at the Institute of Molecular Genetics in Moscow as part of research on fragments of adrenocorticotropic hormone. Early work examined short ACTH-derived sequences that retained neurotrophic effects while lacking the endocrine activity of the full hormone. Semax entered clinical use in Russia during the 1990s, where it received registration for several neurological indications. Outside that region it remained primarily a laboratory research material rather than an approved therapeutic. English-language literature on it grew more slowly and frequently cited the original Russian studies.
Purity assessment relies mainly on reversed-phase high-performance liquid chromatography, which separates the target heptapeptide from truncated sequences, deletion analogues, and oxidised forms. Mass spectrometry, usually coupled to liquid chromatography, confirms identity through the expected molecular ion and reveals modifications such as methionine sulfoxide formation. Amino acid analysis can verify composition, and tandem mass spectrometry supports sequence confirmation. Ultraviolet detection near 254 to 280 nanometres is convenient because the phenylalanine and histidine residues absorb in that region. Nuclear magnetic resonance is rarely used for routine release testing.
Common degradation pathways include oxidation of the methionine side chain, hydrolysis of the peptide backbone, and aggregation under unfavourable pH or concentration. Stability studies typically monitor the main peak by chromatography and report total related substances as a percentage. Because no official monograph exists, acceptance criteria vary between laboratories, and reported purity values are not directly comparable across suppliers. Analysts therefore document the method, column, and detection wavelength alongside each result, and open questions remain about how much biological activity the oxidised forms retain.
Solid semax is typically supplied as a lyophilised powder that is hygroscopic and sensitive to moisture, light, and repeated temperature cycling. Long-term storage of the dry peptide is generally recommended at approximately -20 degrees Celsius, while shorter working periods may use refrigeration at 2 to 8 degrees Celsius. Vials should remain tightly closed and desiccated when brought to room temperature, because condensation can damage the material before it is weighed. Dividing a batch into aliquots is preferable to thawing one container repeatedly.
| Property | Value | Notes |
|---|---|---|
| Chemical class | Synthetic heptapeptide | ACTH(4-7) analogue |
| Sequence | Met-Glu-His-Phe-Pro-Gly-Pro | Free N terminus, unmodified side chains |
| Molecular weight | 813.9 Da | Free base; salt forms differ |
| Appearance | White to off-white powder | Lyophilised solid |
| Solubility | Freely soluble in water | Hydrophilic; polar solvents preferred |
Development took place during the 1980s at institutes of the Russian Academy of Sciences, where peptide fragments of ACTH were screened for cognitive and neuroprotective effects. The compound received regulatory approval in Russia as a nasal preparation, marketed for conditions such as ischemic stroke, transient ischemic attacks, and optic nerve disorders. Registration in other countries has not followed. Most published clinical reports originate from a small number of Russian research groups, and independent replication outside that setting remains limited. The regulatory status therefore differs sharply between Russia and the rest of the world.
Laboratory work points toward modulation of neurotrophic signaling, particularly expression of brain-derived neurotrophic factor and nerve growth factor in hippocampal tissue. Studies also describe effects on monoamine turnover, inflammatory mediators, and oxidative markers. These observations come mainly from animal models and cultured cells, so the causal chain in humans is not firmly established. Whether the reported molecular changes translate into measurable clinical benefit is an open question. Reviews generally present the mechanism as plausible rather than demonstrated.
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.
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。
Laboratory descriptions of the material are consistent across suppliers. It appears as a white to off-white lyophilized powder that dissolves readily in water and in polar organic solvents such as dimethyl sulfoxide. Aqueous solutions are clear and colorless at low concentrations. Because the peptide contains methionine, oxidation at the sulfur atom is a recognized degradation pathway, and handling notes usually call for protected, desiccated storage. Reported purity for research-grade lots is generally above 95 percent as measured by reversed-phase high-performance liquid chromatography.
The compound is registered in Russia as a pharmaceutical product, most commonly formulated as a nasal solution, and has been used in that setting since the 1990s. Outside that jurisdiction it is generally handled as a research chemical rather than an approved medicine. Regulatory status therefore differs sharply between countries, and material sold internationally may not correspond to the Russian pharmaceutical formulation. Documentation with commercial samples is typically limited to a certificate of analysis covering purity and identity, not clinical status or local legal classification.
Semax is a synthetic heptapeptide with the sequence Met-Glu-His-Phe-Pro-Gly-Pro. It corresponds to the ACTH(4-7) fragment extended at the C-terminus by a Pro-Gly-Pro tripeptide, an addition intended to slow enzymatic breakdown. The molecular formula is C37H51N9O10S and the molecular mass is approximately 814 daltons. In the literature it is often described as an ACTH(4-10) analog, although that label reflects a naming convention as much as a precise structural relationship. The compound was developed in Russia and remains most closely associated with that research tradition.
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。
=== Head and neck cancer === Tobacco smoking is the main risk factor for head and neck cancer. Cigarette smokers have a lifetime increased risk for head and neck cancer that is 5 to 25 times higher than the general population. The person who used to smoke's risk of developing head and neck cancer begins to approach the risk in the general population 15 years after smoking cessation. In addition, people who smoke have a worse prognosis than those who have never smoked. Furthermore, people who continue to smoke after a diagnosis of head and neck cancer have the highest probability of dying compared to those who have never smoked. This effect is seen in patients with HPV-positive head and neck cancer as well. Passive smoking, both at work and at home, also increases the risk of head and neck cancer. Using tobacco together with alcohol is an especially strong risk factor for head and neck cancer, causing 72% of all cases. This rises to 89% when looking specifically at laryngeal cancer. Smokeless tobacco (including products where tobacco is chewed) is also a cause of oral cancer. Cigar and pipe smoking are also important risk factors for oral cancer and have a dose-dependent relationship, with more consumption leading to higher chances of developing cancer. The use of electronic cigarettes may also lead to the development of head and neck cancers due to the substances like propylene glycol, glycerol, nitrosamines, and metals contained therein, which can cause damage to the airways.
== Terminology == The term accepted point mutation was initially used to describe the mutation phenomenon. However, the acronym PAM was preferred over APM due to readability, and so the term point accepted mutation is used more regularly. Because the value
Matter is composed of atoms and what makes up atoms. Matter has intrinsic or rest mass. In the limited range of recognized experience of the nineteenth century, it was found that such rest mass is conserved. Einstein's 1905 theory of special relativity showed that rest mass corresponds to an equivalent amount of rest energy. This means that rest mass can be converted to or from equivalent amounts of (non-material) forms of energy, for example, kinetic energy, potential energy, and electromagnetic radiant energy. When this happens, as recognized in twentieth-century experience, rest mass is not conserved, unlike the total mass or total energy. All forms of energy contribute to the total mass and total energy. For example, an electron and a positron each have rest mass. They can perish together, converting their combined rest energy into photons which have electromagnetic radiant energy but no rest mass. If this occurs within an isolated system that does not release the photons or their energy into the external surroundings, then neither the total mass nor the total energy of the system will change. The produced electromagnetic radiant energy contributes just as much to the inertia (and to any weight) of the system as did the rest mass of the electron and positron before their demise. Likewise, non-material forms of energy can perish into matter, which has rest mass. Thus, conservation of energy (total, including material or rest energy) and conservation of mass (total, not just rest) are one (equivalent) law.
It is especially popular to use this kind of sauce with freshly cut cucumbers, which are almost wholly immersed in the sauce, making a salad called 'mizeria'. Dill sauce is used hot for baked freshwater fish and for chicken or turkey breast, or used hot or cold for hard-boiled eggs. A dill-based soup, (zupa koperkowa), served with potatoes and hard-boiled eggs, is popular in Poland. Whole stems including roots and flower buds are used traditionally to prepare Polish-style pickled cucumbers (ogórki kiszone), especially the so-called low-salt cucumbers (ogórki małosolne). Whole stems of dill (often including the roots) also are cooked with potatoes, especially the potatoes of autumn and winter, so they resemble the flavour of the newer potatoes found in summer. Some kinds of fish, especially trout and salmon, traditionally are baked with the stems and leaves of dill. In the Czech Republic, white dill sauce made of cream (or milk), butter, flour, vinegar, and dill is called 'koprová omáčka' (also 'koprovka' or 'kopračka') and is served either with boiled eggs and potatoes, or with dumplings and boiled beef. Another Czech dish with dill is a soup called 'kulajda' that contains mushrooms (traditionally wild ones). In Germany, dill is popular as a seasoning for fish and many other dishes, chopped as a garnish on potatoes, and as a flavouring in pickles. In the UK, dill may be used in fish pie. In Bulgaria, dill is widely used in traditional vegetable salads, and most notably the yogurt-based cold soup Tarator.
Sources: en.wikipedia.org
peptide-C(O)NHCH2CO2− + O2 + 2 [H] → peptide-C(O)NHCH(OH)CO2− + H2O This process shown above is the hydroxylation of a methylene group (-CH2-) by O2, and this process relies on a copper ion cofactor. Dopamine beta-hydroxylase, also a copper-containing enzyme, effects a similar transformation. The PAL subunit then completes the conversion, by catalyzing elimination from the hydroxylated glycine:
== Road closure == An ice road will typically be closed as a result of deterioration of the running or operating surface, before there is any risk of ice cover failure. Surface deterioration can happen when the ice surface becomes too soft, or because of an excessive amount of meltwater on its surface. Mid-season road closures can also happen for similar reasons, and also because of inclement weather, such as a blizzard. If the ice road is part of a winter road, then closure can also be due to an over-land segment that has become unserviceable.
In 2009, True was featured prominently in Christopher McDougall's best selling book Born to Run. The book told the story of the Copper Canyons ultra marathon and the Tarahumara, while promoting the endurance running hypothesis, arguing that humans left the forests and moved to the savannas by developing the ability to run long distances in order to hunt prey by simply outlasting them in a long chase. Becoming a central character in a best selling book changed True's life significantly. Previously he had lived a quiet simple life, not seeing himself as the eccentric and amazing person in the book. He said he sometimes felt like he had to "live up to the expectations of the book" and told people that the book contained exaggerations and inaccuracies. Nevertheless, he became active on Facebook where he encouraged people to follow him. It was through Facebook that he met Maria Walton, who became his girlfriend for the last two years of his life. True also began using his celebrity status to help raise funds for the annual Copper Canyon race. He spoke at various events, beginning with a Saucony sponsored event in Utah, and then eventually traveling to Sweden, Denmark, and England. According to Walton, True was never comfortable with his fame, only wanting to be known as someone who was genuine and real.
=== 2000-present === In 2000, the company opened a central laboratory in Singapore, building on clinical-development services formed in Singapore in 1996. In 2013, it expanded the capacity of the laboratory by 50%. In March 2001, the company sold Covance Pharmaceutical Packaging Services to Fisher Scientific for $137.5 million. In August 2005, it acquired GFI Clinical Services, an 80-bed clinical pharmacology business, from West Pharmaceutical Services for $5.7 million. In April 2006, the company acquired eight early phase clinical pharmacology sites from Radiant Research for $65 million. In June 2006, it acquired Signet Laboratories, a provider of monoclonal antibodies used in the research of cancer, infectious disease, and neurodegenerative disease, for $8.95 million. In 2007, the company opened a laboratory in Shanghai, China. In 2019, it opened a research and development center in Shanghai. In August 2008, the company acquired a campus in Greenfield, Indiana from Eli Lilly and Company and executed a 10-year service drug development service agreement with Lilly. In December 2008, the company acquired a minority equity stake in Caprion Proteomics, a provider of proteomics-based services to the pharmaceutical industry. The company was acquired by Chicago Growth Partners in July 2012. In 2009, the company acquired the Gene Expression Laboratory from Merck & Co. and entered into a five-year, $145 million contract to provide Merck with genomic analysis services.
=== Protein-based materials and sustainability === A major strand of Mezzenga's work concerns the development of protein-derived and food-based materials as sustainable platforms for advanced technologies. His group has pioneered the use of amyloid fibrils as building blocks for functional nanocomposites, including biodegradable materials with sensing and shape-memory properties. In 2016, Mezzenga and collaborators reported amyloid–carbon hybrid membranes for universal water purification. The technology exploits supramolecular metal–ligand interactions between heavy-metal ions and protein amyloid fibrils, allowing simultaneous removal of a wide range of contaminants with high binding affinities. The membranes exhibit unusually high permeability, enabling operation with minimal energy input. This research led to patented technologies and the creation of an ETH Zurich spin-off company, BluAct Technologies, which has tested and deployed the approach in multiple countries. Mezzenga has also contributed to the development of conceptual frameworks for evaluating the sustainability of water purification technologies at large, emphasizing energy efficiency and material performance.
Sources: en.wikipedia.org
reactivity series Also activity series. An empirical, calculated, and structurally analytical progression of a series of metals, arranged by their general reactivity from highest to lowest and used to summarize information about their reactions with acids and water and the methods used to extract them from ores.
While many languages and dialects are spoken in the United States, English is by far the most commonly spoken and written. English was designated the official language of the United States by Executive Order 14224 in March 2025. However, the U.S. has never had a statutory official language, as Congress has never passed a law to designate English as official for all three federal branches. Some laws, such as U.S. naturalization requirements, nonetheless standardize English. Twenty-eight states and the United States Virgin Islands have laws that designate English as the sole official language; 19 states and the District of Columbia have no official language. Three states and four U.S. territories have recognized local or indigenous languages in addition to English: Hawaii (Hawaiian), Alaska (twenty Native languages), South Dakota (Sioux), American Samoa (Samoan), Puerto Rico (Spanish), Guam (Chamorro), and the Northern Mariana Islands (Carolinian and Chamorro). In total, 169 Native American languages are spoken in the United States. In Puerto Rico, Spanish is more widely spoken than English. According to the American Community Survey (2020), some 245.4 million people in the U.S. age five and older spoke only English at home. About 41.2 million spoke Spanish at home, making it the second most commonly used language. Other languages spoken at home by one million people or more include Chinese (3.40 million), Tagalog (1.71 million), Vietnamese (1.52 million), Arabic (1.39 million), French (1.18 million), Korean (1.07 million), and Russian (1.04 million).
The Pixel Imaging Mass Spectrometry camera (PImMS) is an ultrafast imaging sensor designed for time-of-flight particle imaging. It was invented by professors of chemistry at the University of Oxford, Mark Brouard and Claire Vallance., Renato Turchetta from IMASENIC (formerly at the STFC Rutherford Appleton Laboratory), and Andrei Nomerotski from Brookhaven National Labs (formerly at the Department of Physics, University of Oxford). The camera and accompanying software have been further developed by Iain Sedgwick (STFC Rutherford Appleton Laboratory), Jaya John John (Department of Physics, University of Oxford), and Jason Lee (Department of Chemistry, University of Oxford). The camera has been used for studies in chemical reaction dynamics, imaging mass spectrometry, and neutron time-of-flight imaging.
=== Mechanism of action === Nitrogen containing bisphosphonates, which include ibandronate, pamidronate and alendronate exert their effects on osteoclasts mainly by inhibiting the synthesis of isoprenoid lipids such as isopentenyl diphosphate (IPP), farnesyl diphosphate (FPP), and geranylgeranyl diphosphate (GGPP) via the mevalonate pathway. These isoprenoids are used in posttranslational modification(prenylation) of small GTPases such as Ras, Rho, and Rac. These prenylated GTPases are necessary for various cellular processes including osteoclast morphology, endosome trafficking, and apoptosis. Alendronate has also been shown to impair the function of osteclast lysosomes.
=== Diseases === Medical conditions associated with weight gain include hypothyroidism, Cushing's syndrome, Polycystic Ovary Syndrome (PCOS), and congestive heart failure. Medical conditions such as cancer, gastrointestinal illness, psychiatric disorders, infections, endocrine disorders, and neurologic disorders may lead to weight loss.
Sources: en.wikipedia.org
It is a synthetic seven-amino-acid peptide built from the ACTH(4-7) sequence plus a Pro-Gly-Pro tail. It belongs to the family of short ACTH fragments studied for nervous-system effects. Its backbone contains only standard amino acids.
It contains the 4-7 fragment of adrenocorticotropic hormone extended at the C terminus. That truncation removes the region associated with steroidogenic activity. The design intent was to keep neurotrophic properties while avoiding full hormonal effects.
No natural source of the intact heptapeptide is known. It is produced by solid-phase peptide synthesis. Some related ACTH fragments arise as hormone processing products, but the Pro-Gly-Pro extension is a designed addition rather than a natural sequence.
Dry powder is usually kept at about -20 degrees Celsius for long-term storage and at 2 to 8 degrees Celsius for short working periods. Containers should stay sealed and protected from light and moisture to limit degradation.