If you have been reading about neurotrophic signaling 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.
Updated 2026-05-06. Numbers and descriptions here follow the published literature rather than marketing material.
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.
Terminology around the compound varies by source. It appears in catalogues and papers as Semax, as the heptapeptide ACTH(4-7)-Pro-Gly-Pro, and under various alphanumeric laboratory codes used by individual suppliers. These names refer to the same sequence but may imply different salt forms, purity grades, or counter-ions. Peptide databases usually list the free base mass, while product descriptions sometimes report acetate or trifluoroacetate salts with a different formula weight. Because naming conventions for research peptides are not standardised across vendors, checking the declared sequence and measured mass is more reliable than relying on a trade name alone.
Published research covers ischemic stroke, traumatic brain injury, cognitive impairment, optic nerve conditions and attention-related measures. Much of the human evidence comes from small trials conducted in one country, which limits how far the results generalize. Animal models supply the larger share of the data, and effects seen in rodents do not transfer automatically to people. Reviews have noted that methodological reporting is often incomplete, making it difficult to pool results or compare treatment schedules across studies.
Pharmacokinetic accounts emphasize rapid breakdown. After intravenous dosing the intact peptide disappears from blood within minutes, and nasal delivery produces low but measurable concentrations. Metabolites rather than the parent molecule may account for part of the observed activity, although the relative contribution is unresolved. Dosing in the literature varies widely and no optimal schedule has been agreed. These gaps are regularly cited as a reason the findings have not produced broad clinical adoption beyond the original research setting.
Proposed mechanisms center on neurotrophic signaling rather than on classical melanocortin receptor activation. Rodent experiments have reported shifts in the expression of brain-derived neurotrophic factor and nerve growth factor after administration, together with changes in the associated receptor systems. Several authors argue that the peptide acts largely through its degradation products and their interaction with peptidergic pathways, but this remains a hypothesis rather than a settled finding. No single molecular target has been identified in a way that the field broadly accepts.
| 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 |
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.
Pharmacological accounts link semax to melanocortin signalling and to modulation of neurotrophic factor expression, particularly brain-derived neurotrophic factor and nerve growth factor. Much of this evidence comes from rodent studies using intranasal delivery, a route chosen because it allows peptides to reach the central nervous system with limited systemic exposure. Whether the same mechanisms operate in humans at comparable magnitude remains an open question. The precise receptor or receptors responsible for the reported behavioural and neuroprotective effects have not been conclusively identified.
Clinical reports describe use in ischaemic stroke, transient ischaemic attack, optic nerve conditions, and cognitive complaints, but most of these studies are small and were conducted in a single region. Systematic reviews have generally described the evidence base as limited in size and variable in methodological quality. Randomised controlled data suitable for international regulatory assessment are scarce. As a result, major treatment guidelines outside Russia do not include the peptide, and interest in it remains largely research-driven rather than routine clinical.
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。
Nickel-60 is the daughter product of the extinct radionuclide 60Fe (half-life 2.62 My). Because 60Fe has such a long half-life, its persistence in materials in the Solar System at high enough concentrations may have generated observable variations in the isotopic composition of 60Ni. Therefore, the abundance of 60Ni in extraterrestrial material may provide insight into the origin of the Solar System and its early history/very early history. Unfortunately, nickel isotopes appear to have been heterogeneously distributed in the early Solar System. Therefore, so far, no actual age information has been attained from 60Ni excesses. 60Ni is also the stable end-product of the decay of 60Zn, the last rung of the alpha ladder.
Performance of manufactured batteries has improved over time. For example, from 1991 to 2005 the energy capacity per price of lithium-ion batteries improved more than ten-fold, from 0.3 W·h per dollar to over 3 W·h per dollar. In the period from 2011 to 2017, progress has averaged 7.5% annually. Overall, between 1991 and 2024, prices for all types of lithium-ion cells (in dollars per kWh) fell approximately 99%. From 1991 to 2018, energy density more than tripled. Efforts to increase energy density contributed significantly to cost reduction. Energy density can also be increased by improvements in the chemistry of the cell, for instance, by full or partial replacement of graphite with silicon. Silicon anodes enhanced with graphene nanotubes to eliminate the premature degradation of silicon allow for record-breaking battery energy density of up to 350 Wh/kg and lowering EV prices to be competitive with ICEs. Differently sized cells of the same format (shape) with the same chemistry may have different energy densities. Jelly roll cells usually have a higher energy density than coin or prismatic cells of the same Ah, because of a tighter/compresses packing of the cell layers. Among cylindrical cells, those with a larger size have a larger energy density, albeit the exact value strongly depends on the thickness of the electrode layers. The disadvantage of large cells is decrease of the heat transfer from the cell to its surroundings.
Australia is the only country in which Burger King does not operate under its own name. When the company set about establishing operations down under in 1971, it found that its business name was already trademarked by a takeaway food shop in Adelaide. As a result, Burger King provided the Australian franchisee, Jack Cowin, with a list of possible alternative names derived from pre-existing trademarks already registered by Burger King and its then corporate parent Pillsbury, that could be used to name the Australian restaurants. Cowin selected the "Hungry Jack" brand name, one of Pillsbury's US pancake mixture products, and slightly changed the name to a possessive form by adding an apostrophe "s" forming the new name Hungry Jack's. After the expiration of the trademark in the late 1990s, Burger King unsuccessfully tried to introduce the brand to the continent. After losing a lawsuit filed against it by Hungry Jack's ownership, the company ceded the territory to its franchisee. Hungry Jack's is now the only Burger King brand in Australia; Cowin's company Hungry Jack's Pty Ltd. is the master franchise and thus is now responsible for oversight of the operations that country with Burger King only providing administrative and advertising support to ensure a common marketing scheme for the company and its products.
=== Cognitive problems ("fibro fog") === Many people with fibromyalgia experience cognitive problems often known as "fibro fog". The CDC and the American Pain Society recognize these problems as a major feature of fibromyalgia. About 75% of people with fibromyalgia report significant problems with concentration, memory, and multitasking. A 2018 meta-analysis found that the largest differences between people with fibromyalgia and healthy subjects were in inhibitory control, memory, and processing speed. A 2023 scoping review grouped effects into subjective cognitive dysfunction, perceived variability, changes in functional activities, and participation limitations. A 2017 review found that the neuropsychological mechanisms underlying brain fog may be similar to those in isolated functional cognitive disorders. One hypothesis is that chronic pain in fibromyalgia compromises attention systems, resulting in cognitive problems.
Sources: en.wikipedia.org
where c = composition, p = polarity, and v = molecular volume; and are constants of squares of the inverses of the mean distance for each property, respectively equal to 1.833, 0.1018, 0.000399. According to Grantham's distance, most similar amino acids are leucine and isoleucine and the most distant are cysteine and tryptophan.
The US, UK, and Soviet Union rejected it; US ambassador to the UN Thomas Pickering stated that the French proposal was unacceptable, because it went beyond Council resolutions on the Iraqi invasion. France dropped this proposal when it found "no tangible sign of interest" from Baghdad.
== Transmission == Citrus greening was originally thought to be a viral disease, but is caused by a bacterium, carried by insect vectors. Infection can arise in various climates and is often associated with different species of psyllid insects. For example, citrus crops in Africa become infected under cool conditions as the bacteria are transmitted by the African citrus psyllid Trioza erytreae, an insect that favors cool and moist conditions for optimal activity. Citrus crops in Asia, however, are often infected under warm conditions as the bacteria are transmitted by the Asian citrus psyllid Diaphorina citri. The young larval stage is the most suitable for acquisition of ca. L. asiaticus by the Asian citrus psyllid Diaphorina citri, and some cultivars show greater efficiency in transmitting the disease to the vector than others. Temperature also shows a great influence in the parasite-host relationship between the bacteria and the insect vector, affecting how it is acquired and transmitted by the insects. The causative agents are fastidious phloem-restricted, Gram-negative bacteria in the gracilicutes clade. The Asian form, ca. L. asiaticus is heat tolerant. This means the greening symptoms can develop at temperatures up to 35 °C (95 °F). The African form, ca. L. africanus, and American form, ca. L. americanus, are heat sensitive, thus symptoms only develop when the temperature is in the range 20–25 °C (68–77 °F). Although T. erytreae is the natural vector of African citrus greening and D.
=== Horizontal pitch === Horizontal pitch (HP) is a unit of length defined by the Eurocard printed circuit board standard used to measure the horizontal width of rack-mounted electronic equipment, similar to the rack unit (U) used to measure vertical heights of rack-mounted equipment. One HP is 0.2 inches (1⁄5″) or 5.08 millimetres wide.
In the heart it can cause myocardial infarction In the brain, it can cause a transient ischemic attack (TIA), and, in prolonged blood obstruction, stroke. Blockage of arteries that supply arms or legs may result in necrosis and gangrene Temporary or permanent decrease or loss of other organ functions In septic embolism, there can be infection of the affected tissue or even septic shock, potentially leading to gangrene and sepsis
Sources: en.wikipedia.org
=== Pests and predators === The fruit bodies of B. edulis can be infected by the parasitic mould-like fungus Hypomyces chrysospermus, known as the bolete eater, which manifests itself as a white, yellow, or reddish-brown cottony layer over the surface of the mushroom. Some reported cases of stomach ache following consumption of dried porcini have been attributed to the presence of this mould on the fruit bodies. The mushroom is also used as a food source by several species of mushroom flies, as well as other insects and their larvae. An unidentified species of virus was reported to have infected specimens found in the Netherlands and in Italy; fruit bodies affected by the virus had relatively thick stems and small or no caps, leading to the name "little-cap disease". Boletus edulis is a food source for animals such as the banana slug (Ariolimax columbianus), the long-haired grass mouse, the red squirrel, and, as noted in one isolated report, the fox sparrow.
== Mechanism of action == Ionophores are chemical compounds that reversibly bind and transport ions through biological membranes in the absence of a protein pore. This can disrupt the membrane potential, and thus these substances could exhibit cytotoxic properties. Ionophores modify the permeability of biological membranes toward certain ions to which they show affinity and selectivity. Many ionophores are lipid-soluble and transport ions across hydrophobic membranes, such as lipid bilayers found in the living cells or synthetic vesicles (liposomes), or liquid polymeric membranes (carrier-based ion selective electrodes). Structurally, an ionophore contains a hydrophilic center and a hydrophobic portion that interacts with the membrane. Ions are bound to the hydrophilic center and form an ionophore-ion complex. The structure of the ionophore-ion complex has been verified by X-ray crystallography.
Midtown Raleigh is a relatively new term used to describe the residential and commercial area lying on the northside of the I-440 Beltline and is part of North Raleigh. It is roughly framed by Glenwood/Six Forks Road to the West, Wake Forest Road to the East, and Millbrook Road to the North. It includes shopping centers such as North Hills and Crabtree Valley Mall. It also includes North Hills Park and part of the Raleigh Greenway System. The term was coined by the Greater Raleigh Chamber of Commerce, developer John Kane and planning director Mitchell Silver. The News & Observer newspaper started using the term for marketing purposes only. The Midtown Raleigh Alliance was founded on July 25, 2011, as a way for community leaders to promote the area. The center of the area, especially around the North Hills development at the junction of Six Forks Road and the Beltline, is experiencing rapid urbanization as several high-rise buildings have been built since 2010.
Katherine J. Franz (born 1972) is an American chemist. She is the chair of the department of chemistry at Duke University. She studies metal ion coordination in biological systems and looks to use the insight to manage species such as copper and iron. Franz was awarded the American Chemical Society Award for Encouraging Women into Careers in the Chemical Sciences.
Legislative measures to limit the sale of hydrogen peroxide products to concentrations of 12% or lower for the general public have been made in the European Union. A key disadvantage is the high susceptibility of TATP to accidental detonation, causing injuries and deaths among illegal bomb-makers, which has led to TATP being referred to as the "Mother of Satan". TATP was found in the accidental explosion that preceded the 2017 terrorist attacks in Barcelona and surrounding areas. Large-scale TATP synthesis is often betrayed by excessive bleach-like or fruity smells. The smell can even penetrate into clothes and hair in amounts that are quite noticeable; this was reported in the 2016 Brussels bombings. TATP was found in the bombs used in the 2026 New York City bombing attempt outside of Gracie Mansion on the Upper East Side of Manhattan, New York, but the devices did not explode.
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.
The main proposal is modulation of neurotrophic factors such as brain-derived neurotrophic factor, supported largely by animal experiments. Receptor-level targets have not been firmly established. Most reviews describe the mechanism as only partially characterized.