This is a working overview of counter-ion, written for readers who want more than a one-paragraph summary but less than a textbook.
This page was last updated on 2026-02-10 and is reviewed periodically as new material appears.
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.
Verification of a supplied batch generally combines a certificate of analysis with independent testing, because certificates are self-reported documents. A typical package includes a chromatographic trace, a mass spectrum, and a stated water or counter-ion content. Batch-to-batch consistency matters more than a single purity figure when results are compared across experiments. No single mandatory standard governs research-grade peptide release, so laboratories are expected to define their own acceptance criteria. Residual trifluoroacetate from purification is a frequently overlooked counter-ion.
Lyophilized material is chemically stable for extended periods when kept dry, cold, and protected from light. The powder is hygroscopic, so vials should be warmed to room temperature before opening to reduce condensation on the contents. Once dissolved, the peptide is far less stable because peptide bonds are susceptible to hydrolysis and the methionine residue can oxidize. Solutions are typically aliquoted and held at 2-8 °C for short intervals or frozen for longer ones, and repeated freeze-thaw cycles should be avoided.
Routine characterization relies on reversed-phase high-performance liquid chromatography to establish purity and on mass spectrometry to confirm molecular identity. Electrospray ionization and matrix-assisted laser desorption ionization are both used for mass verification. Amino acid analysis and peptide mapping can detect sequence errors. Common impurities include truncated sequences, methionine sulfoxide formed by oxidation, and deamidated products. Chromatograms are usually recorded near 214 nm, where the peptide backbone absorbs, and purity is reported as the percentage area of the principal peak.
| Property | Value | Notes |
|---|---|---|
| Molecular weight | ~813.9 Da (free heptapeptide) | N-acetylated form is about 42 Da heavier |
| Residue count | 7 (heptapeptide) | Four residues from ACTH(4-10), three added |
| Appearance | White to off-white powder | Usually supplied lyophilized |
| Solubility class | Freely soluble in water | Also dissolves in DMSO and polar organic solvents |
| Related parent fragment | ACTH(4-10) | Parent motif is Met-Glu-His-Phe |
Development is attributed to researchers at the Institute of Molecular Genetics in Moscow during the early 1980s, building on earlier Soviet work with ACTH fragments. Russian regulatory approval followed for intranasal use, and the compound has remained commercially available there for decades. Most published human data originate from Russian and, later, some Eastern European clinical reports, which are not always accessible in English translation. Outside that region the material is generally handled as a research chemical rather than a licensed medicine.
Regulatory status differs sharply between jurisdictions. In Russia the peptide is registered as a prescription nasal preparation, while agencies such as the United States Food and Drug Administration have not approved it for any indication. Products sold elsewhere are typically labeled for laboratory research only, and such labels shift responsibility for safe handling to the purchaser. Because the same name covers pharmaceutical-grade nasal drops and bulk research powder, identity and purity documentation becomes the main practical concern when comparing sources.
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.
==== Polyol process ==== The polyol process is a particularly useful method because it yields a high degree of control over both the size and geometry of the resulting nanoparticles. In general, the polyol synthesis begins with the heating of a polyol compound such as ethylene glycol, 1,5-pentanediol, or 1,2-propylene glycol7. An Ag+ species and a capping agent are added (although the polyol itself is also often the capping agent). The Ag+ species is then reduced by the polyol to colloidal nanoparticles. The polyol process is highly sensitive to reaction conditions such as temperature, chemical environment, and concentration of substrates. Therefore, by changing these variables, various sizes and geometries can be selected for such as quasi-spheres, pyramids, spheres, and wires. Further study has examined the mechanism for this process as well as resulting geometries under various reaction conditions in greater detail.
Housing Secretary Angela Rayner reintroduces mandatory local housing targets in an overhaul of planning rules; the new Labour government has pledged to build 1.5 million new homes by 2029. 2024 Summer Olympics: Nathan Hales wins a third gold medal for Team GB in shooting, while in swimming, the men's 4 × 200 m freestyle relay team win a fourth. 31 July Huw Edwards appears at Westminster Magistrates' Court and pleads guilty to three counts of making indecent images of children. He will be sentenced on 16 September. Tulip Siddiq, Economic Secretary to the Treasury and Labour MP for Hampstead and Highgate, becomes the first MP of the new Parliament to be placed under investigation by the Standards Commissioner, over a failure to register rental income on a London property. 2024 Southport stabbing Far-right protesters clash with police outside Downing Street, as violent disorder following the stabbings spills over into a second day. More than 100 people are arrested. The unrest also spreads to Hartlepool, which sees a police car torched and several officers injured. Further pockets of disorder break out in Manchester and Aldershot, where demonstrators gather outside hotels housing migrants.
Transplantation experiments involving frog and newt epidermis indicated that the mesodermal signals are conserved between species but the epidermal response is species-specific meaning that the mesoderm instructs the epidermis of its position and the epidermis uses this information to make a specific structure.
=== Definition === The definition of chemistry has changed over time, as new discoveries and theories add to the functionality of the science. The term "chymistry", in the view of noted scientist Robert Boyle in 1661, meant the subject of the material principles of mixed bodies. In 1663, the chemist Christopher Glaser described "chymistry" as a scientific art, by which one learns to dissolve bodies, and draw from them the different substances on their composition, and how to unite them again, and exalt them to a higher perfection. The 1730 definition of the word "chemistry", as used by Georg Ernst Stahl, meant the art of resolving mixed, compound, or aggregate bodies into their principles; and of composing such bodies from those principles. In 1837, Jean-Baptiste Dumas considered the word "chemistry" to refer to the science concerned with the laws and effects of molecular forces. This definition further evolved until, in 1947, it came to mean the science of substances: their structure, their properties, and the reactions that change them into other substances—a characterization accepted by Linus Pauling. More recently, in 1998, Professor Raymond Chang broadened the definition of "chemistry" to mean the study of matter and the changes it undergoes.
The GTS site has the ability to assume two conformations depending on the interaction of adenine or guanine. For the stop codon UAG, the Thr32 from the GTS site will hydrogen bond with the guanine in the +3 position. If the stop codon has guanine in the second position (UGA), the YxxCxxxF motif stacks on the codon which causes the GTS site to face away from codon.
Sources: en.wikipedia.org
== Methods == Forensic chemists rely on a multitude of instruments to identify unknown substances found at a scene. Different methods can be used to determine the identity of the same substance, and it is up to the examiner to determine which method will produce the best results. Factors that forensic chemists might consider when performing an examination are the length of time a specific instrument will take to examine a substance and the destructive nature of that instrument. They prefer using nondestructive methods first, to preserve the evidence for further examination. Nondestructive techniques can also be used to narrow down the possibilities, making it more likely that the correct method will be used the first time when a destructive method is used.
=== Highly controllable properties === Porous silicon studies conducted in 1995 showed that the behaviour of porous silicon can be altered in between "bio-inert", "bioactive" and "resorbable" by varying the porosity of the silicon sample. The in-vitro study used simulated body fluid containing ion concentration similar to the human blood and tested the activities of porous silicon sample when exposed to the fluids for prolonged period of time. It was found that high porosity mesoporous layers were completely removed by the simulated body fluids within a day. In contrast, low to medium porosity microporous layers displayed more stable configurations and induced hydroxyapatite growth.
Those whose half-lives exceed a few percent of the age of the Earth (about 4.6×109 years) survive from its formation and are remnants of nucleosynthesis that occurred in stars before the formation of the Solar System. For example, the isotope 23892U (t1/2 = 4.463×109 years) of uranium is still fairly abundant in nature, but the shorter-lived isotope 23592U (t1/2 = 0.704×109 years) is now 138 times rarer. 35 of these primordial radionuclides have been identified (see List of nuclides and Primordial nuclide for details). Radiogenic nuclides (such as 22688Ra (t1/2 = 1600 years), an isotope of radium) that are formed by radioactive decay. They occur in the decay chains of primordial isotopes of uranium or thorium. Some of these nuclides are very short-lived, such as isotopes of francium. There exist about 50 of these daughter nuclides that have half-lives too short to be primordial, and which exist in nature solely due to decay from longer lived radioactive primordial nuclides. Nuclides that are continuously being made in another fashion that is not simple spontaneous radioactive decay (i.e., only one atom involved with no incoming particle) but instead involves a natural nuclear reaction. These occur when atoms react with natural neutrons (from cosmic rays, spontaneous fission, or other sources), or are bombarded directly with cosmic rays. The latter, if non-primordial, are called cosmogenic nuclides. Other types of natural nuclear reactions produce nuclides that are said to be nucleogenic nuclides.
During an interview for Al Jazeera television on 17 November 2005, he said his election as MP earlier in the year was "despite all the efforts made by the British government, the Zionist movement and the newspapers and news media which are controlled by Zionism". In Trials of the Diaspora: A History of Anti-Semitism in England, Anthony Julius cites this interview as one example of Galloway pandering to the antisemitic prejudices of his audience. According to Julius, Galloway merely refers to the "right-wing press" in the British media, whereas he has the habit of adding the word "Zionist" when speaking on television in the Arab world. A few years later, in a May 2009 speech given at a meeting in Westminster, Galloway said: "I do not agree with the argument that there is a shadowy Jewish influence. Israel is doing what America wants it to do and to argue otherwise is to go down the dark tunnel of racist antisemitism". Galloway criticised the British government's support of Israel during the Gaza war and condemned the genocide of Palestinians in the Gaza Strip. Galloway disputed reports from the Israeli government about the October 7 attacks. Specifically, he disputed the number of babies killed and suggested two-thirds of those killed were from the IDF. He also suggested that those who propagate the official Israeli government account of 7 October are "war criminals". The Board of Deputies of British Jews, the largest Jewish community organisation in the UK, has called Galloway "a demagogue and conspiracy theorist".
Sources: en.wikipedia.org
There is no cure for CMT, but its symptoms can be managed to maintain quality of life. Although no proven treatment can alter disease progression, physical and occupational therapy can help preserve muscle strength, flexibility, and mobility. Orthopedic devices like ankle-foot orthoses (AFOs) are commonly used to correct foot drop and improve gait. In some cases, surgical interventions may be necessary to straighten toes, lower arches, or fuse joints to enhance stability. Pain management may involve physical therapy, assistive devices, or medications for neuropathic pain. Drugs with gabapentin and pregabalin may be used for neuropathic pain. NSAIDs and SSRIs are also used for non-neuropathic pain related to skeletal deformities caused by CMT. Treadmill training in patients has especially been shown to improve symptoms associated with impaired walking and balancing over time. Strength training paired with creatine supplements can also help as it may compensate for weak distal muscles and help alleviate CMT-related chronic fatigue. Certain drugs, such as vincristine (a chemotherapy agent), should be avoided altogether in CMT patients due to their known toxicity to nerves. Regular follow-up with healthcare providers is essential to adapt care as the disease progresses.
The Court of Justice held that the Directive could be relied on by her because equality was also a general principle of EU law. Fourth, if the defendant is an emanation of the state, even if not central government, it can still be bound by Directives. In Foster v British Gas plc the Court of Justice held that Mrs Foster was entitled to bring a sex discrimination claim against her employer, British Gas plc, which made women retire at age 60 and men at 65, if (1) pursuant to a state measure, (2) it provided a public service, and (3) had special powers. This could also be true if the enterprise is privatised, as it was held with a water company that was responsible for basic water provision. Fifth, national courts have a duty to interpret domestic law "as far as possible in the light of the wording and purpose of the directive". Textbooks (though not the Court itself) often called this "indirect effect". In Marleasing SA v La Comercial SA the Court of Justice held that a Spanish Court had to interpret its general Civil Code provisions, on contracts lacking cause or defrauding creditors, to conform with the First Company Law Directive article 11, that required incorporations would only be nullified for a fixed list of reasons. The Court of Justice quickly acknowledged that the duty of interpretation cannot contradict plain words in a national statute. But, if a member state has failed to implement a Directive, a citizen may not be able to bring claims against other non-state parties. It must instead sue the member state itself for failure to implement the law.
On 7 April 2023, Lula re-established the National Council for LGBTQIA+ Rights, a 38-member body of advisors charged with proposing policies and supporting campaigns aimed towards support for the LGBTQIA+ community in Brazil. The Ministry of Human Rights and Citizenship will be charged with funding for the council. The body previously existed from 2010 until the Bolsonaro presidency.
== Antisense oligonucleotide development == Developments in ASO modification are separated into three generations. Generation one is called backbone-modified and focuses on the phosphodiester group of the nucleotide. This impacts inter-nucleotide binding. These modifications led to better distribution, reduced urinary excretion, and prolonged residence time of the ASOs in the cell. Some examples of first generation modifications include the addition of a phosphorothioate group (PS), methyl group, or nitrogen. The most common is the phosphorothioate group (PS) in which the oxygen atoms of a phosphodiester group are replaced with sulfur atoms, greatly improving efficacy and reducing degradation. Generation two is sugar-modified, focused on the ribose sugar of the nucleotide. This generation saw improved binding affinity while reducing degradation. Some examples of generation two modifications are the substitution of R group with morpholine group (MO) and the usage of phosphorodiamidate morpholino oligomer (PMO) and thiomorpholine oligomer (TMO) as linkages between the ribose sugar and phosphodiester group in the backbone. Generation three is nucleobase-modified, the least common type of modification. These modifications enhanced binding affinity and cell penetration while reducing degradation and off-target effects. Examples include the introduction of G-clamps, pseudoisocytosine, and the substitution of bases with amine, thione, halogen, alkyl, alkenyl, or alkynyl groups.
As the arteriosclerosis progresses, blood flows less easily through rigid and narrowed blood vessels, making the blood more likely to form a thrombosis (clot). Sudden blockage of a blood vessel may lead to an infarction (stroke or heart attack). However, the effects of smoking on the heart may be more subtle. These conditions may develop gradually, given the smoking–healing cycle (the human body heals itself between periods of smoking). Therefore, a person who smokes may develop less significant disorders, such as worsening or maintenance of unpleasant dermatological conditions, e.g., eczema, due to reduced blood supply. Smoking also increases blood pressure and weakens blood vessels.
Sources: en.wikipedia.org
The sequence is Met-Glu-His-Phe-Pro-Gly-Pro, a seven-residue peptide. The first four residues correspond to the ACTH(4-10) fragment, and Pro-Gly-Pro is added at the C-terminus. N-acetylated versions also appear in the literature and differ in mass.
Semax is a synthetic analog of the ACTH(4-10) fragment rather than a copy of the full hormone. Truncation plus the added tail removes the steroidogenic portion of ACTH. That distinction explains why it is studied for nervous-system effects instead of adrenal stimulation.
It is registered as a prescription product in Russia and has been used there clinically, chiefly by the intranasal route. No approval exists in the United States or the European Union. Availability elsewhere typically falls under research-chemical distribution, with varying purity documentation.
Dry powder is normally held at -20 °C or lower, away from light and moisture. Sealed vials can also be kept at 2-8 °C for shorter intervals. Warming to room temperature before opening prevents condensation.