neurotrophic factor raises a handful of sensible questions. This page answers them in order, starting with the fundamentals and moving to applications.
This page was last updated on 2026-07-27 and is reviewed periodically as new material appears.
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.
Semax is a synthetic peptide created in the Soviet Union during the early 1980s by researchers working in Moscow. It was built from the short adrenocorticotropic hormone fragment known as ACTH(4-10), and the chain was then extended with three additional amino acids. The resulting molecule was named semax and entered clinical use in Russia in 1994. It is generally described as a nootropic and neuroprotective agent rather than as a hormone analogue.
The parent fragment ACTH(4-10) carries the sequence Met-Glu-His-Phe-Arg-Trp-Gly. Semax replaces the arginine and tryptophan positions with a proline-glycine-proline tail, giving Met-Glu-His-Phe-Pro-Gly-Pro. That change removes residues associated with adrenal stimulation, so the peptide does not drive cortisol release the way full ACTH does. This distinction shapes how the compound is grouped in the literature, where it sits with neuropeptides and peptide neuromodulators rather than with corticosteroids.
| Property | Value | Notes |
|---|---|---|
| Molecular formula | C37H51N9O10S | Free acid form of the heptapeptide; depends on terminal groups |
| Molecular mass | About 813.9 g/mol | Average mass used for mass spectrometry confirmation |
| Appearance | White to off-white solid | Supplied as a lyophilised powder; hygroscopic |
| Solubility class | Freely soluble in aqueous media | Water, saline, and phosphate buffers; limited organic solubility |
| Typical storage temperature | -20 degrees Celsius | Long term and dry; short working periods may use 2 to 8 degrees Celsius |
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.
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。
The prevalence of this condition is difficult to ascertain because a number of stricter or looser definitions have been used. It is recommended that the term reactive hypoglycemia be reserved for the pattern of postprandial hypoglycemia which meets the Whipple criteria (symptoms correspond to measurably low glucose and are relieved by raising the glucose), and that the term idiopathic postprandial syndrome be used for similar patterns of symptoms where abnormally low glucose levels at the time of symptoms cannot be documented. To assist in diagnosis, a doctor may order an HbA1c test, which measures the blood sugar average over the two or three months before the test. The more specific 6-hour glucose tolerance test can be used to chart changes in the patient's blood sugar levels before ingestion of a special glucose drink and at regular intervals during the six hours following to see if an unusual rise or drop in blood glucose levels occurs. According to the U.S. National Institutes of Health (NIH), a blood glucose level below 70 mg/dL (3.9 mmol/L) at the time of symptoms followed by relief after eating confirms a diagnosis for reactive hypoglycemia.
Progesterone and some of its metabolites, such as 5β-dihydroprogesterone, are agonists of the pregnane X receptor (PXR), albeit weakly so (EC50 >10 μM). In accordance, progesterone induces several hepatic cytochrome P450 enzymes, such as CYP3A4, especially during pregnancy when concentrations are much higher than usual. Perimenopausal women have been found to have greater CYP3A4 activity relative to men and postmenopausal women, and it has been inferred that this may be due to the higher progesterone levels present in perimenopausal women. Progesterone modulates the activity of CatSper (cation channels of sperm) voltage-gated Ca2+ channels. Since eggs release progesterone, sperm may use progesterone as a homing signal to swim toward eggs (chemotaxis). As a result, it has been suggested that substances that block the progesterone binding site on CatSper channels could potentially be used in male contraception.
For polymeric nanoparticles, the induction of stimuli-responsiveness has usually relied heavily upon well-known polymers that possess an inherent stimuli-responsiveness. Certain polymers that can undergo reversible phase transitions due to changes in temperature or pH have aroused interest. Arguably the most utilized polymer for activation-modulated delivery is the thermo-responsive polymer poly(N-isopropylacrylamide). It is readily soluble in water at room temperature but precipitates reversibly from when the temperature is raised above its lower critical solution temperature (LCST), changing from an extended chain conformation to a collapsed chain. This feature presents a way to change the hydrophilicity of a polymer via temperature. Efforts also focus on dual stimuli-responsive drug delivery systems, which can be harnessed to control the release of the encapsulated drug. For example, the triblock copolymer of poly(ethylene glycol)-b-poly(3-aminopropyl-methacrylamide)-b-poly(N-isopropylacrylamide) (PEG-b-PAPMA-b-PNIPAm) can self-assemble to form micelles, possessing a core–shell–corona architecture above the lower critical solution temperature. It is also pH responsive. Therefore, drug release can be tuned by changing either temperature or pH conditions.
Sources: en.wikipedia.org
Early space food was primarily composed of bite-sized cubes, freeze-dried powders, and thick liquids stuffed in aluminum tubes. First used on the 3rd Mercury mission in 1962, US astronaut John Glenn was the first to eat directly from an aluminum tube, specifically applesauce. However the tubes were eventually discontinued as their design did not allow the food to be smelled or seen, and the texture also posed limitations on the variety of food that could be made available. Freeze-dried powders that could be re-hydrated were also available, as well as high-calorie bite sized cubes of food. These solutions had their own challenges, however over time, the powders were made easier to re-freeze, and the cubes were coated in gelatin to prevent crumbling on the equipment. With the introduction of the "spoon bowl," on the Apollo 8 mission, astronauts were able to open the contents of the package and eat the simple meal with a spoon. For lunch on Vostok 1 (1961), Yuri Gagarin ate from three 160 g (5.6 oz) toothpaste-type tubes, two of which contained servings of puréed meat and one which contained chocolate sauce. In August 1961, Soviet Cosmonaut Gherman Titov became the first human to experience space sickness on Vostok 2; he holds the record for being the first person to vomit in space. This event "heralded the need for space flight nutrition." John Glenn, as the first American to orbit Earth in 1962, was to experiment with eating in weightless conditions. Some experts had been concerned that weightlessness would impair swallowing.
=== Story === The player follows Angela's journey toward the "one perfect book" in the Library from the view of Roland, a Fixer who becomes her servant after trespassing into the Library uninvited. The story is broken up into various chapters. As Roland's past is gradually shed light on and Angela comes closer to becoming human, the Library becomes an ever-growing threat to the City, urging the Associations (organized groups of fixers, often centered around a single theme) to take action. Argalia, a mysterious Fixer known as the "Blue Reverberation" recruits various characters into a group known as the "Reverberation Ensemble" for an unknown cause, culminating in them breaking into the Library, scattering to the ten floors to claim the Light for their greatest performance that will overturn the City. The Library ultimately emerges victorious after a hard-fought battle. Just as Angela finally gains a human body, Roland betrays Angela and reveals his true motive for coming to the Library: to make her suffer as revenge for her actions instigating the Distortion phenomenon and indirectly causing the death of his wife Angelica, a former Color Fixer known as the "Black Silence". Roland ultimately fails to defeat the Library and pleads for Angela to kill him, or he will kill her if she falters. If all of Angela's Floor realizations have not been completed, she will kill Roland and the Librarians and obtain the one true book.
Although most of its ecological habitats are still intact, there is an increasing population with industrial and tourism development. This is putting more pressure on the vegetation through the process of logging, overgrazing, woodcutting and infrastructure of development plans. Though the tree is widespread, it has become fragmented with the development that has occurred in its habitats. Many of its populations are suffering poor regeneration. Human activities have greatly reduced the population through overgrazing, and feeding the flowers and fruits to the livestock of the island. One of the greatest threats is the gradual drying out of the Socotra Archipelago, which has been an ongoing process for the last few hundred years. This has resulted in non-flourishing trees, and the duration of the mist and cloud around the area seems to also be decreasing. Increasingly arid environments are predicted to cause a 45 percent reduction in the available habitat for D. cinnabari by 2080. Another threat comes from goat grazing in the area, which prevents regeneration and prevents seedlings developing in locations other than rocky outcrops. Additional threats include harvesting of its resin and use of its leaves as fodder during the dry season. Presently some trees have been used to make beehives. This was generally prohibited; this displays how the species may be threatened by a breakdown in the traditional practices of the island. The best preserved and largest stand of D. cinnabari is on the limestone plateau named Rokeb di Firmihin.
Sources: en.wikipedia.org
It is described as a synthetic analogue of the ACTH(4–10) fragment, a short segment of adrenocorticotropic hormone. Its sequence differs from that fragment and includes two proline residues, which influence stability and behaviour in solution.
It appears in Russian pharmaceutical listings as a nasal formulation, but it is not an authorised medicine in the United States or the European Union. Outside those markets it is normally encountered as a research chemical rather than a prescription product.
Laboratory and animal work points to melanocortin signalling and changes in neurotrophic factor levels, especially brain-derived neurotrophic factor. The exact receptor targets and the degree to which these findings transfer to humans are still unresolved.
Registered medical products are most often 0.1% nasal drops. Research suppliers ship lyophilized powder, usually in milligram quantities, which is dissolved before use. The active peptide is the same in both cases; presentation and excipients differ.