This is a working overview of lyophilised powder, written for readers who want more than a one-paragraph summary but less than a textbook.
This page was last updated on 2026-08-01 and is reviewed periodically as new material appears.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Typical purity | ≥95% by HPLC | Research-grade material |
| Detection wavelength | 214 nm | Peptide bond absorbance |
| Reconstitution medium | Sterile water or saline | Prepare fresh or aliquot immediately |
| Storage (solution) | -80 °C, single-use aliquots | Avoid repeated freeze-thaw cycles |
| Common salt form | Acetate or trifluoroacetate | Affects mass and solubility |
Practical handling follows from those properties. Bulk material is best divided into single-use portions soon after receipt, because each thaw exposes the whole container to moisture and temperature cycling. Vials should be allowed to reach room temperature before opening to prevent condensation on the powder. Low-binding plasticware reduces loss of dilute solutions, and sterile filtration is used when a preparation must remain free of microbial growth. Records of batch number, reconstitution date and storage history are what allow a later analytical result to be interpreted meaningfully.
Identity and purity of Semax are established mainly by reversed-phase high-performance liquid chromatography coupled with mass spectrometry. The chromatographic trace gives a purity estimate as a percentage of total peak area, while electrospray or matrix-assisted laser desorption ionization confirms the molecular mass against the calculated value. Amino acid analysis and sequence-specific fragmentation provide further confirmation when a supplier's chain of custody is unclear. Vendors frequently quote a purity figure without stating the detection wavelength or the integration method, which limits how far one number can be compared with another.
Stability depends heavily on physical state. Lyophilized powder held dry, cold and dark retains its content over long periods, whereas dissolved peptide begins to change within days at room temperature. The most cited degradation route is oxidation of the methionine residue, which converts the peptide to a sulfoxide form that elutes differently on chromatography. Hydrolysis of amide bonds and adsorption onto container walls contribute smaller losses. Buffers that exclude oxygen from the headspace slow the oxidation pathway, but no single condition prevents all change indefinitely.
The C-terminal Pro-Gly-Pro extension is not incidental. Proline-rich tails are known to resist several common peptidases, and the published literature attributes the longer half-life of Semax, relative to unmodified ACTH fragments, to this feature. The modification also removes the melanocyte-stimulating and corticosteroidogenic activity that characterizes longer ACTH-derived sequences. Because the molecule is small and hydrophilic, it is typically formulated as an aqueous solution for intranasal or parenteral delivery. Acetylation or amidation at the termini appears in closely related research peptides and shifts the mass by a fixed increment.
Reported pharmacological work centers on neurotrophic signaling, including changes in BDNF and NGF expression in hippocampal tissue in animal models. Human data come largely from studies conducted in Russia, and how well those results generalize to other populations remains an open question. Regulatory status differs sharply by jurisdiction: Semax is a registered prescription medicine in Russia, while it holds no approved marketing status in the United States or the European Union. Outside such jurisdictions it is generally handled as a research chemical, which affects both documentation and quality expectations.
Semax is a synthetic heptapeptide whose sequence is Met-Glu-His-Phe-Pro-Gly-Pro. It was developed as a fragment analog of adrenocorticotropic hormone, modeled specifically on the ACTH(4-10) region. The first four residues reproduce that fragment, while a Pro-Gly-Pro tripeptide is appended at the C-terminus. Work on the compound originated in Russia, where it entered clinical use as an intranasal preparation. Its sequence places it among short regulatory peptides studied for effects on the central nervous system rather than on the adrenal axis.
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.
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。
Pituitary prolactin is controlled by the Pit-1 transcription factor, which binds to the gene at several sites including a proximal promoter. This promoter is inhibited by dopamine and stimulated by estrogens, neuropeptides, and growth factors. Estrogens can also suppress dopamine. Interaction with neuropeptides is still a matter of active research: no specific prolactin-releasing hormone has been identified. It is known that mice react to both VIP and TRH, but humans seem to only react to TRH. There are prolactin-releasing peptides that work in vitro, but whether they deserve their name has been questioned. Oxytocin does not play a large role. Mice without a posterior pituitary do not raise their prolactin levels even with suckling and oxytocin injection, but scientists have yet to identify which specific hormone produced by this region is responsible. In birds (turkeys), VIP is a powerful prolactin-releasing factor, while peptide histidine isoleucine has almost no effect.
In jaundice owing to hemolysis (prehepatic, or hemolytic, jaundice), the pathophysiology is that overproduction of bilirubin from the extravascular or intravascular hemolysis overwhelms the capacity of the liver to excrete it. The bilirubin present in the plasma is largely unconjugated in this setting as they haven't been taken up and conjugated by the liver. In this case, total serum bilirubin increases while the ratio of direct bilirubin to indirect bilirubin remains 96 to 4 as up to 96%-99% of bilirubin in the bile are conjugated mentioned above. Although there were some studies that showed an inverse correlation between serum bilirubin level and prevalences of ischemic coronary artery disease, cancer mortality, or colorectal cancer in general population, the potential benefits of the chemopreventive function of bilirubin and their causative relations haven't been proved.
Iboxamycin is a synthetic lincosamide or oxepanoprolinamide antibiotic. It binds to the bacterial ribosome in both Gram-negative and Gram-positive bacteria and it has been found to effective against bacteria which are resistant to other antibiotics that target the large ribosomal subunit. It was developed by combining an oxepanoproline unit with the aminooctose residue of clindamycin. Iboxamycin is effective against ESKAPE bacteria, methicillin-resistant Staphylococcus aureus (MRSA), Enterococcus, Clostridioides difficile, and Listeria monocytogenes, indicating an extended spectrum when compared to clindamycin. Isotopic labeling of iboxamycin with tritium indicated that it binds 70 times more tightly to the ribosome than clindamycin. Iboxamycin can be administered orally and is safe when administered to mice. It is a bacteriostatic antibiotic. Cresomycin - a similar antibiotic developed from iboxamycin
Actinium is found only in traces in uranium ores – one tonne of uranium in ore contains about 0.2 milligrams of 227Ac – and in thorium ores, which contain about 5 nanograms of 228Ac per one tonne of thorium. The actinium isotope 227Ac is a transient member of the uranium-actinium series decay chain, which begins with the parent isotope 235U (or 239Pu) and ends with the stable lead isotope 207Pb. The isotope 228Ac is a transient member of the thorium series decay chain, which begins with the parent isotope 232Th and ends with the stable lead isotope 208Pb. Another actinium isotope (225Ac) is transiently present in the neptunium series decay chain, beginning with 237Np (or 233U) and ending with thallium (205Tl) and near-stable bismuth (209Bi); even though all primordial 237Np has decayed away, it is continuously produced by neutron knock-out reactions on natural 238U. The low natural concentration and the close similarity of physical and chemical properties to those of lanthanum and other lanthanides, which are always abundant in actinium-bearing ores, render separation of actinium from the ore impractical. The most concentrated actinium sample prepared from raw material consisted of 7 micrograms of 227Ac in less than 0.1 milligrams of La2O3, and complete separation was never achieved. Instead, actinium is prepared, in milligram amounts, by the neutron irradiation of 226Ra in a nuclear reactor.
=== Names === Oxitriptan is the generic name of the drug and its INNTooltip International Nonproprietary Name. Brand names of oxitriptan include Cincofarm, Levothym, Levotonine, Oxyfan, Telesol, Tript-OH, and Triptum.
Sources: en.wikipedia.org
=== Woodhouse Grammar School === After the First World War, the former residence of ornamental plasterer Thomas Collins (1735–1830) in the Woodhouse area of Finchley was reconstructed; the house became The Woodhouse School in 1923. A blue plaque commemorating Thomas Collins is on the wall outside the present college office. The school coat of arms with the motto 'Cheerfulness with Industry' is still displayed above the stage in the college hall. During the Second World War, the school continued to function while the basement was used by the ARP service. The names of the forty-seven former pupils who died during WWII are recorded in a hand-illuminated Roll of Honour which hangs at the foot of the main staircase near the front entrance to the college. The Roll of Honour also records the names of the four houses of the old grammar school: Gordon, Livingstone, Nightingale and Scott.
== Species complex == While traditionally described as a cosmopolitan species, recent genetic research has identified Octopus vulgaris as a species complex. There are currently six recognized members of the Octopus vulgaris species complex. Each member of the complex is associated with specific geographic regions, often associated with continental coastlines.
Christians constitute the majority of the city's population, most of whom follow the Russian Orthodox Church. The Patriarch of Moscow serves as the head of the Church and lives in the Danilov Monastery. Moscow was called the "city of 40 times 40 churches"—before the Russian Revolution in 1917. Moscow is Russia's capital of Eastern Orthodox Christianity, which has been the country's traditional religion. Other religions practiced in Moscow include Buddhism, Hinduism, Islam, Judaism, Yazidism, and Rodnovery (Slavic Native Faith). The Moscow Mufti Council claimed that Muslims numbered around 1.5 million of the city's 10.5 million population in 2010. The city has four mosques.
ADP + phosphate + glutathione The 3 substrates of this enzyme are ATP, gamma-L-glutamyl-L-cysteine, and glycine, whereas its 3 products are ADP, phosphate, and glutathione. This enzyme belongs to the family of ligases, specifically those forming carbon-nitrogen bonds as acid-D-amino-acid ligases (peptide synthases). The systematic name of this enzyme class is gamma-L-glutamyl-L-cysteine:glycine ligase (ADP-forming). Other names in common use include glutathione synthetase, and GSH synthetase. This enzyme participates in glutamate metabolism and glutathione metabolism. At least one compound, Phosphinate is known to inhibit this enzyme. The biosynthetic mechanisms for synthetases use energy from nucleoside triphosphates, whereas synthases do not. Glutathione synthetase stays true to this rule, in that it uses the energy generated by ATP. Initially, the carboxylate group on γ-glutamylcysteine is converted into an acyl phosphate by the transfer of an inorganic phosphate group of ATP to generate an acyl phosphate intermediate. Then the amino group of glycine participates in a nucleophilic attack, displacing the phosphate group and forming GSH. After the final GSH product is made, it can be used by glutathione peroxidase to neutralize reactive oxygen species (ROS) such as H2O2 or Glutathione S-transferases in the detoxification of xenobiotics.
==== MeSH E05.478.550 – immunization ==== MeSH E05.478.550.520 – immunization, passive MeSH E05.478.550.520.050 – adoptive transfer MeSH E05.478.550.520.050.400 – immunotherapy, adoptive MeSH E05.478.550.545 – immunization schedule MeSH E05.478.550.550 – immunization, secondary MeSH E05.478.550.600 – immunotherapy, active MeSH E05.478.550.600.890 – vaccination MeSH E05.478.550.650 – mass immunization
Sources: en.wikipedia.org
A review of different cell geometries with their specific electric configurations is available in the literature. However, ICR cells can belong to one of the following two categories: closed cells or open cells. Several closed ICR cells with different geometries were fabricated and their performance has been characterized. Grids were used as end caps to apply an axial electric field for trapping ions axially (parallel to the magnetic field lines). Ions can be either generated inside the cell or can be injected to the cell from an external ionization source. Nested ICR cells with double pair of grids were also fabricated to trap both positive and negative ions simultaneously. The most common open cell geometry is a cylinder, which is axially segmented to produce electrodes in the shape of a ring. The central ring electrode is commonly used for applying radial excitation electric field and detection. DC electric voltage is applied on the terminal ring electrodes to trap ions along the magnetic field lines. Open cylindrical cells with ring electrodes of different diameters have also been designed. They proved not only capable in trapping and detecting both ion polarities simultaneously, but also they succeeded to separate positive from negative ions radially. This presented a large discrimination in kinetic ion acceleration between positive and negative ions trapped simultaneously inside the new cell. Several ion axial acceleration schemes were recently written for ion–ion collision studies.
== History == Flurpiridaz F-18 is a fluorine 18-labeled agent, developed by Lantheus Medical Imaging for the diagnosis of coronary artery disease. The efficacy and safety of flurpiridaz (18F) was evaluated in two prospective, multicenter, open-label clinical studies in adults with either suspected CAD (Study 1: NCT03354273) or known or suspected CAD (Study 2: NCT01347710). Study 1 evaluated the sensitivity (ability to designate an imaged patient with disease as positive) and specificity (ability to designate an imaged patient without disease as negative) of flurpiridaz (18F) for the detection of significant CAD in subjects with suspected CAD, who were scheduled for invasive coronary angiography (ICA). Across three flurpiridaz (18F) imaging readers, estimates of sensitivity ranged from 74% to 89% and estimates of specificity ranged from 53% to 70% for CAD defined as at least 50% narrowing of an artery. Study 2 evaluated the sensitivity and specificity of flurpiridaz (18F) for the detection of significant CAD in subjects with known or suspected CAD, who had ICA without intervention within 60 days prior to imaging or were scheduled for ICA. Across three flurpiridaz (18F) imaging readers, estimates of sensitivity ranged from 63% to 77% and estimates of specificity ranged from 66% to 86% for CAD defined as at least 50% narrowing of an artery.
11 May A logic gate for computation at femtosecond timescales is demonstrated. A study shows that infusing the nourishing cerebrospinal fluid from around brain cells of young mice into aged brains rejuvenates aspects of the brain, identifying FGF17 as a key target for potential therapeutics such as of anti-aging. Scientists close a missing link in the potential origin of life from a RNA world – synergistic formation of peptides and ever-longer RNAs or peptide-decorated RNA, leading to a protein world. A study suggests that in children at age 8–12 during two years, time gaming or watching digital videos can be positively correlated with measures intelligence, albeit correlations with overall screen time (including social media, socializing and TV) were not investigated and 'time gaming' did not differentiate between categories of video games (e.g. shares of games' platform and genre). 12 May Sagittarius A*, the supermassive black hole at the center of the Milky Way galaxy, is imaged for the first time by the Event Horizon Telescope team. Researchers report that lunar soil has been used to grow plants for the first time. Researchers identify the 425 biggest fossil fuel extraction projects globally, of which 40% as of 2020 are new projects that haven't yet started extraction. They conclude that "defusing" these "carbon bombs" – worked on by only "few actors" to date – would be necessary for climate change mitigation of global climate goals.
=== Photochromic compounds === Photochromic compounds have the ability to switch between a range or variety of colors. Their ability to display different colors lies in how they absorb light. Different isomeric manifestations of the molecule absorbs different wavelengths of light, so that each isomeric species can display a different color based on its absorption. These include photoswitchable compounds, which are proteins that can switch from a non-fluorescent state to that of a fluorescent one given a certain environment. The most common organic molecule to be used as a photochrome is diarylethene. Other examples of photoswitchable proteins include PADRON-C, rs-FastLIME-s and bs-DRONPA-s, which can be used in plant and mammalian cells alike to watch cells move into different environments.
Sources: en.wikipedia.org
Solid peptide is best kept frozen at about minus 20 degrees Celsius in a sealed container with desiccant. It should be allowed to reach room temperature before opening to prevent condensation. Repeated warming and cooling of the same vial is discouraged.
Reversed-phase liquid chromatography establishes purity, while mass spectrometry confirms molecular mass. The two techniques are normally used together. Retention time alone is not sufficient evidence of identity.
Different counterions change the mass per unit of peptide and can shift chromatographic behavior. Two samples of equal stated purity may therefore not be directly comparable. Reports should specify the counterion whenever quantitative comparisons are made.
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.