If you have been reading about Semax and want a single page that covers the useful parts, this is it: definitions, context, how it is studied, and the questions that come up repeatedly.
Last reviewed on 2026-03-06. 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. 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.
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.
The proposed mechanism centres on neurotrophic signalling rather than direct receptor activation. Semax is reported to increase expression of brain-derived neurotrophic factor and nerve growth factor in several brain regions, and to shift the balance between excitatory and inhibitory neurotransmitter systems. Interaction with melanocortin receptors has been suggested because of the parent ACTH fragment. Many of these findings come from rodent studies, and the extent to which they translate to human physiology remains an open question.
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.
| Property | Value | Notes |
|---|---|---|
| Molecular formula | C37H51N9O10S | Contains one methionine sulfur atom |
| Molecular mass | Approximately 814 Da | Consistent with a seven-residue peptide |
| Appearance | White to off-white powder | Typical lyophilized form |
| Solubility | Freely soluble in water | Also soluble in dimethyl sulfoxide |
| Typical storage | -20 °C, desiccated | Limits methionine oxidation |
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。
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。
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.
Ribulose-1,5-bisphosphate carboxylase/oxygenase, commonly known by the abbreviations RuBisCo, rubisco, RuBPCase, or RuBPco, is an enzyme (EC 4.1.1.39) involved in the light-independent (or "dark") part of photosynthesis, including the carbon fixation by which atmospheric carbon dioxide is converted by plants and other photosynthetic organisms to energy-rich molecules such as glucose. It emerged approximately four billion years ago in primordial metabolism prior to the presence of oxygen on Earth. It is the most abundant enzyme on Earth. In chemical terms, it catalyzes the carboxylation of ribulose-1,5-bisphosphate (also known as RuBP).
This is an energy dependent process that becomes more energetically unfavorable for the yeast cell as fermentation progressed and ethanol levels increase, creating "passive leakage" of excess hydrogen ions into the cell. The cell's hydrogen ion pumps have to work even harder to maintain its internal pH so it sends a signal to the symport proteins to stop bringing other ions. This is one of the reasons why late fermentation nitrogen additions have little to no effective as the transport mechanisms of the nitrogen into the cell are shut down.
Self was concerned that NAA had not ever designed a fighter, insisting they obtain the drawings and study the wind-tunnel test results for the P-40, before presenting them with detailed design drawings based on the agreed concept. NAA purchased the drawings and data from Curtiss for £56,000, confirming the purchase with the British Purchasing Commission. The commission approved the resulting detailed design drawings, signing the commencement of the Mustang project on 4 May 1940, and firmly ordering 320 on 29 May 1940. Prior to this, NAA only had a letter of intent for an order of 320 aircraft. Curtiss engineers accused NAA of plagiarism. The British Purchasing Commission stipulated armament of four .303 in (7.7 mm) machine guns (as used on the Tomahawk), a unit cost of no more than $40,000, and delivery of the first production aircraft by January 1941. In March 1940, 320 aircraft were ordered by Freeman, who had become the executive head of the Ministry of Aircraft Production (MAP) and the contract was promulgated on 24 April. The NA-73X, which was designed by a team led by lead engineer Edgar Schmued, followed the best conventional practice of the era, designed for ease of mass manufacturing. The design included several new features. One was a wing designed using laminar flow airfoils, which were developed co-operatively by NAA and the National Advisory Committee for Aeronautics (NACA). These airfoils generated low drag at high speeds.
=== 1950s === 1950: Isabella Abbott became the first Native Hawaiian woman to receive a PhD in any science; hers was in botany. 1950: Esther Lederberg was the first to isolate lambda bacteriophage, a DNA virus, from Escherichia coli K-12. 1952: Grace Hopper completed what is considered to be the first compiler, a program that allows a computer user to use English-like words instead of numbers. It was known as the A-0 compiler. 1956: The Wu experiment was a nuclear physics experiment conducted in 1956 by the physicist Chien-Shiung Wu, born in China but having become an American citizen in 1954, in collaboration with the Low Temperature Group of the US National Bureau of Standards. That experiment showed that parity could be violated in weak interaction.
Sources: en.wikipedia.org
Half-Life 2: Episode Two received an average score of 90.68% based on 22 reviews on the review aggregator GameRankings. On Metacritic, it has an average score of 90 out of 100 based on 21 reviews, indicating "universal acclaim". As part of The Orange Box compilation, Episode Two shared with Portal and Team Fortress 2 in winning "Computer Game of the Year" at the 11th Annual Interactive Achievement Awards. Dan Adams of IGN rated the game 9.4 out of 10 and praised its improved visuals and expansive environments, but cited the short six-hour length as a drawback. He said: "Any way you look at it, Episode Two stands out, even among the Half-Life series, as something special ... a burly experience packed into roughly six hours or so that offers up all the diversity, level design, and thoughtful gameplay we've known while making sure to propel the story forward and leave us wanting more." Bit-tech awarded the game a ten out of ten score, citing approval of how the story turns and the introduction of side stories and new characters. 1UP.com said that it was "vivid, emotionally engaging, and virtually unsurpassed". PC Gamer UK felt that Episode Two was "the most sumptuous chapter of the Half-Life saga, and by a country mile". The New York Times enjoyed the gameplay, saying that battles "often require as much ingenuity as they do fast reflexes". Computer and Video Games said that, although the Source engine was dated, the "wonderful art design and the odd bit of technical spit-shine ensure that Episode Two [...] doesn't lose any of its wow factor".
) as a crystal and powder. The signal observed, called the Pake doublet, was from the magnetically active hydrogens in water. Pake then calculated the proton-proton bond length. NMR measurements were further revolutionized when commercial machines became available in the 1960s. Before this, NMR experiments involved constructing massive projects, locating large magnets, and hand wiring miles of copper coil. Proton NMR remained the most popular technique throughout advancements in following decades, but 2H and 3H were used in other flavors of NMR spectroscopy. 2H has a different magnetic moment and spin than 1H, but generally a much smaller signal. Historically, deuterium NMR is a poor alternative to proton NMR, but has been used to study the behavior of lipids on cell membranes. A variant of 2H NMR called 2H-SNIF has shown potential for understating position-specific isotope compositions and comprehending biosynthetic pathways. Tritium is also used in NMR, as it is the only nucleus more sensitive than 1H, generating very large signals. However, tritium's radioactivity discouraged many studies of 3H-NMR. While tritium's radioactivity discourages use in spectroscopy, tritium is essential for nuclear weapons. Scientists began understanding nuclear energy as early as the 1800s, but large advancements were made in studies of the atomic bomb in the early 1940s. Wartime research, especially the Manhattan Project, greatly advanced the understanding of radioactivity. 3H is a byproduct in reactors, a result of hitting lithium-6 with neutrons, producing almost 5 MeV of energy.
In the first seven years of the reign of Juan Carlos I, the transition to democracy was completed, making Spain the only non-communist dictatorship left in Europe. The Spanish transition, of which the end is usually placed in the victory of the PSOE in the October 1982 elections, is part of the third "democratizing wave" of the 20th century, which began in Portugal in 1974 with the "Carnation Revolution" and ended with the fall of the Berlin Wall in 1989.
=== Bone repair === Bone has a unique and well-documented natural healing process that normally is sufficient to repair fractures and other common injuries. Misaligned breaks due to severe trauma, as well as treatments like tumor resections of bone cancer, are prone to improper healing if left to the natural process alone. Scaffolds composed of natural and artificial components are seeded with mesenchymal stem cells and placed in the defect. Within four weeks of placing the scaffold, newly formed bone begins to integrate with the old bone and within 32 weeks, full union is achieved. Further studies are necessary to fully characterize the use of cell-based therapeutics for treatment of bone fractures. Stem cells have been used to treat degenerative bone diseases in dogs. The normally recommended treatment for dogs that have Legg–Calve–Perthes disease is to remove the head of the femur after the degeneration has progressed. Recently, mesenchymal stem cells have been injected directly in to the head of the femur, with success not only in bone regeneration, but also in pain reduction.
The Black Mesa Research Facility (also simply called Black Mesa) is a fictional large underground laboratory complex that serves as the primary setting for the video game Half-Life and its expansions, as well as its unofficial remake, Black Mesa. It also features in the wider Half-Life universe, including the Portal series. Located in the New Mexico desert in a decommissioned Cold War missile site, it is the former employer of Half-Life's theoretical physicist protagonist, Gordon Freeman, and a competitor of Aperture Science. While the facility ostensibly conducts military-industrial research, its secret experiments into teleportation have caused it to make contact with the alien world of Xen, and its scientists covertly study its life-forms and materials. In a catastrophic event known as the "Black Mesa Incident", an "anti-mass spectrometer" experiment conducted on Xen matter causes a Resonance Cascade disaster that allows aliens to invade Earth, and is the catalyst for the events of the series. Half-Life was critically acclaimed for its storytelling and level design. At the time, the integration of narrative into gameplay through scripted sequences and NPCs instead of through cutscenes was considered groundbreaking for a first-person shooter.
Sources: en.wikipedia.org
== Research == Some of Brayden's research has centered on advanced drug delivery systems and strategies to improve the delivery of macromolecules. He has conducted research on poor intestinal permeability of macromolecules, degradation of peptides in the gastrointestinal tract, and the effects of reduced oral bioavailability on therapeutic effectiveness. His studies have investigated intestinal permeation enhancers to promote peptide absorption, technologies aimed at enhancing intestinal absorption, and methods to reduce the need for injectable drug administration. Another strand of Brayden's work has explored methods such as pH-sensitive encapsulation for delivering macromolecules directly to intestinal regions. These approaches included formulation-based strategies to improve mucosal transport of therapeutic peptides, enabling controlled and site-specific drug release. He has also contributed to translational and interdisciplinary research in drug delivery technologies. He worked on oral peptide drug delivery using silica-based nanotechnology systems and explored biomaterial-based nanocomplexes for drug delivery applications. He documented that intra-articular nanocomplexes entrapping selected molecules reduce inflammation by modulating inflammatory gene expression. His research has also focused on the development of oral formulations of peptide-based therapies as alternatives to injectable administration.
Comprehensive two-dimensional gas chromatography, or GC×GC, is a multidimensional gas chromatography technique that was originally described in 1984 by J. Calvin Giddings and first successfully implemented in 1991 by John Phillips and his student Zaiyou Liu. GC×GC utilizes two different columns with two different stationary phases. In GC×GC, all of the effluent from the first dimension column is diverted to the second dimension column via a modulator. The modulator quickly traps, then "injects" the effluent from the first dimension column onto the second dimension. This process creates a retention plane of the 1st dimension separation x 2nd dimension separation. The oil and gas industry was an early adopter of the technology for the complex oil samples to determine the many different types of hydrocarbons and their isomers. In these types of samples, over 30000 different compounds could be identified in a crude oil with this comprehensive chromatography technology (CCT). The CCT evolved from a technology only used in academic R&D laboratories into a more robust technology used in many different industrial labs. Comprehensive chromatography is used in forensics, food and flavor, environmental, metabolomics, biomarkers and clinical applications. Some of the most well-established research groups in the world that are found in Australia, Italy, the Netherlands, Canada, United States, and Brazil use this analytical technique.
Most of the explosions targeted antennas and active military bases. Early reports suggested that the explosions were at Generalissimo Francisco de Miranda Air Base (La Carlota) and Fort Tiuna, two military installations in Caracas. Large explosions were also reported at Higuerote Airport, on the Venezuelan coast. Helicopters from the 160th Special Operations Aviation Regiment carried Delta Force soldiers into Caracas with air cover provided by the fighters and bombers. One helicopter was damaged by Venezuelan ground defenses but continued on its mission. Federal Bureau of Investigation (FBI) personnel, including the Hostage Rescue Team, accompanied the military to formally arrest Maduro at his compound. The strikes lasted half an hour. Smoke was seen rising from one military hangar in a Caracas base, while another was left unpowered. The strikes happened under the cover of darkness as a result of both the timing of the operation and the US military's disruption of power in the city of Caracas. Multiple shipping containers were destroyed and damaged in the La Guaira port strikes. Satellite imagery from Vantor showed at least five destroyed warehouses, burned vehicles, and a blown-up security post. An aircraft, believed to be a Beechcraft Baron, and a Buk-M2E surface-to-air missile system were destroyed at Higuerote Airport.
== Sample collection == There are no set rules for sample selection in detrital zircon geochronology studies. The objective and scale of the research project govern the type and number of samples taken. In some cases, the sedimentary rock type and depositional setting can significantly affect the result. Examples include:
Marijuana use is also linked to other substance use disorders including nicotine addiction." It also reported that "These findings are consistent with the idea of marijuana as a "gateway drug". However, the majority of people who use marijuana do not go on to use other, "harder" substances. Also, cross-sensitization is not unique to marijuana. Alcohol and nicotine also prime the brain for a heightened response to other drugs and are, like marijuana, also typically used before a person progresses to other, more harmful substances."
Sources: en.wikipedia.org
It is registered as a pharmaceutical product in Russia, where it is typically supplied as a nasal solution. In most other countries it is not an approved drug and is traded as a research chemical instead. Approval status depends entirely on the jurisdiction involved.
Most published work uses intranasal administration, matching the route of the registered Russian formulation. Some animal experiments use intravenous or intraperitoneal injection. The route matters because the intact peptide is cleared rapidly from blood, so exposure differs between methods.
A purity value describes the share of the powder accounted for by the target peptide, usually by high-performance liquid chromatography. It does not confirm that the sequence is correct, which requires mass spectrometry or amino acid analysis. Purity and identity are separate checks.
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.