A practical reference on counter-ion: what it is, how it behaves, what the literature reports, and where the honest uncertainties sit.
Reviewed 2025-11-06. Anything still debated is marked as such rather than presented as settled.
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.
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.
Published research on this peptide originates mainly from Russian laboratories, and the wider international literature is comparatively thin. Studies have used rodent models of stroke, hypoxia, and memory tasks, with a smaller number of human trials reported. Reported outcomes include changes in attention and memory measures, along with effects on neurotrophic factor expression in some experiments. Small sample sizes, inconsistent dosing protocols, and limited independent replication are widely noted limitations, so the strength of the clinical evidence remains an open question.
Semax is a synthetic heptapeptide whose sequence is Met-Glu-His-Phe-Pro-Gly-Pro. The first four residues correspond to the ACTH(4-10) fragment, while the terminal Pro-Gly-Pro extension was added to improve metabolic stability. Its molecular formula is C37H51N9O10S and its monoisotopic mass is approximately 813.9 Da. The compound is classified as a peptide research chemical and as a registered pharmaceutical product in Russia, but it does not hold marketing approval in the European Union or the United States. Naming conventions vary across supplier catalogs.
Development of the compound took place in the Soviet Union during the 1980s, largely through peptide research groups affiliated with the Shemyakin-Ovchinnikov Institute and Moscow State University. Investigators screened fragments of adrenocorticotropic hormone for activity on the central nervous system while attempting to separate cognitive effects from hormonal ones. The shortened sequence was selected because it retained behavioral activity in animal models without stimulating corticosteroid release. Early publications described the molecule as an ACTH(4-10) analog.
| Property | Value | Notes |
|---|---|---|
| Typical purity | 95% or higher | By reversed-phase HPLC area |
| Identity method | Electrospray mass spectrometry | Confirms molecular mass |
| Purity method | Reversed-phase HPLC | Detection near 214 nm |
| Primary degradation | Methionine oxidation | Sulfoxide product, +16 Da |
| Solution storage | 2-8 °C, short term | Aliquot to avoid freeze-thaw |
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.
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.
Semax is a synthetic seven-amino-acid peptide whose sequence extends the ACTH(4-10) fragment with a C-terminal proline-glycine-proline tripeptide. The commonly cited sequence is Met-Glu-His-Phe-Pro-Gly-Pro, giving a molecular formula near C37H51N9O10S and a molecular weight close to 813.9 g/mol. It belongs to the broader class of synthetic ACTH fragments studied for central nervous system effects rather than for adrenal steroid stimulation. In practice the material appears as a lyophilized white powder for laboratory work or as a dilute saline solution in clinical settings.
Destabilizing the molecule in the previous reaction allows the hexose ring to be split by aldolase into two triose sugars: dihydroxyacetone phosphate (a ketose), and glyceraldehyde 3-phosphate (an aldose). Two classes of aldolases exist: class I aldolases, present in animals and plants, and class II aldolases, present in fungi and bacteria. The two classes use distinct mechanisms in cleaving the ketose ring. Electrons delocalized in the carbon-carbon bond cleavage associate with the alcohol group. The resulting carbanion is stabilized by resonance and by a positively charged prosthetic group.
Silicon is a crystalline solid with a blue-grey metallic lustre. Like boron, it is less dense (at 2.33 g/cm3) than aluminium, and is hard and brittle. It is a relatively unreactive element. According to Rochow, the massive crystalline form (especially if pure) is "remarkably inert to all acids, including hydrofluoric". Less pure silicon, and the powdered form, are variously susceptible to attack by strong or heated acids, as well as by steam and fluorine. Silicon dissolves in hot aqueous alkalis with the evolution of hydrogen, as do metals such as beryllium, aluminium, zinc, gallium or indium. It melts at 1414 °C. Silicon is a semiconductor with an electrical conductivity of 10−4 S•cm−1 and a band gap of about 1.11 eV. When it melts, silicon becomes a reasonable metal with an electrical conductivity of 1.0–1.3 × 104 S•cm−1, similar to that of liquid mercury. The chemistry of silicon is generally nonmetallic (covalent) in nature. It is not known to form a cation. Silicon can form alloys with metals such as iron and copper. It shows fewer tendencies to anionic behaviour than ordinary nonmetals. Its solution chemistry is characterised by the formation of oxyanions. The high strength of the silicon–oxygen bond dominates the chemical behaviour of silicon. Polymeric silicates, built up by tetrahedral SiO4 units sharing their oxygen atoms, are the most abundant and important compounds of silicon. The polymeric borates, comprising linked trigonal and tetrahedral BO3 or BO4 units, are built on similar structural principles.
BBC article on Salisbury's School of Embalming Infection risks and embalming by KS Creely. Institute of Occupational Medicine Research Report TM/04/01 Archived at Ghostarchive and the Wayback Machine: TED (14 October 2011), Jae Rhim Lee: My mushroom burial suit, retrieved 1 February 2017
Caelius Aurelianus apparently assigned a special chapter for the discussion of diabetes but this chapter seems to have been lost. I have looked for it in the 1529 edition edited by Johnnes Sichart without success. I have attempted to reconstruct this passage on diabetes from later authors noted for their ability to copy, but have not been able to find it. The early printers discarded the manuscripts after their publications were printed; therefore it is unlikely that this missing section will be found. The chief fact is that the concept of diabetes goes back to Demetrius, who lived in the first century B.C.
The Na+/I− symporter transports two sodium ions across the basement membrane of the follicular cells along with an iodide ion. This is a secondary active transporter that utilises the concentration gradient of Na+ to move I− against its concentration gradient. This is called iodide trapping. Sodium is cotransported with iodide from the basolateral side of the membrane into the cell, and then concentrated in the thyroid follicles to about thirty times its concentration in the blood. I− is moved across the apical membrane into the colloid of the follicle by pendrin. Hydrogen peroxide is also introduced into the follicle by the action of DUX (Dual Oxidase). Iodide is non-reactive, and the reactive I2 species is required for the next step. Thyroid peroxidase (TPO) reduces hydrogen peroxide to water by transferring one electron from two I− atoms that react to form I2. Iodine (I2) is converted into HOI, by hydration with water. Both I2 and HOI iodinate specific tyrosyl residues of the thyroglobulin within the colloid to form 3-monoiodityrosyl (MIT-yl) and 3,5-diiodityrosyl (DIT-yl) residues—introducting iodine atoms at one or both locations ortho to the hydroxyls of tyrosine. The thyroglobulin was synthesised in the ER of the follicular cell and secreted into the colloid. TPO also converts tyrosyl, MIT-yl, and DIT-yl residues into their free radical forms. These forms attack other MIT-yl and DIT-yl residues. When a DIT-yl radical attacks a DIT, T4-yl (peptidic T4) is formed. When a MIT-yl radical attacks a DIT, T3-yl is formed.
Sources: en.wikipedia.org
===== Long dsRNA helix targeting ===== Most viruses produce long dsRNA helices during transcription and replication. In contrast, uninfected mammalian cells generally produce dsRNA helices of fewer than 24 base pairs during transcription. DRACO (double-stranded RNA activated caspase oligomerizer) is a group of experimental antiviral drugs initially developed at the Massachusetts Institute of Technology. In cell culture, DRACO was reported to have broad-spectrum efficacy against many infectious viruses, including dengue flavivirus, Amapari and Tacaribe arenavirus, Guama bunyavirus, H1N1 influenza and rhinovirus, and was additionally found effective against influenza in vivo in weanling mice. It was reported to induce rapid apoptosis selectively in virus-infected mammalian cells, while leaving uninfected cells unharmed. DRACO effects cell death via one of the last steps in the apoptosis pathway in which complexes containing intracellular apoptosis signalling molecules simultaneously bind multiple procaspases. The procaspases transactivate via cleavage, activate additional caspases in the cascade, and cleave a variety of cellular proteins, thereby killing the cell.
=== ECG/EKG === ECGs of patients with cardiac amyloidosis usually show a low voltage in the limb leads, with an unusual extreme right axis. There is usually a normal P-wave, however, it can be slightly prolonged. For patients with light-chain amyloidosis, the QRS complex pattern is skewed, with poor R-waves of the chest leads. In TTR amyloidosis, there is often a discordance between wall thickness suggested by EKG and actual wall thickness, with lower voltages on EKG underestimating wall thickness. Holter monitors can be used to identify asymptomatic arrhythmias. EKG changes may be present, showing low voltage and conduction abnormalities like atrioventricular block or sinus node dysfunction. Atrial fibrillation (AF) is observed in up to 70% of patients at the time of diagnosis, and patients typically have controlled ventricular rates caused by concomitant conduction system disease.
== Metabolism == The exact metabolic pathways of dimethocaine have not been researched, but the different metabolites have been examined in Wistar rats. After administration of dimethocaine, different metabolites have been found and identified in their urine. Due to these metabolites, different metabolic pathways could have been postulated. The main phase I reactions are ester hydrolysis, deethylation, hydroxylation of the aromatic system, or a combination of these three. The main phase II reactions are N-acetylation, glucuronidation and a combination of both. Different cytochrome P450 isozymes are involved in the initial steps of human metabolism. The N-acetylation is catalyzed by the NAT2 isozyme.
Archaeological excavations in Germany and Britain show that in addition to the meat supplied by the army, soldiers hunted animals such as beavers, badgers, foxes, and wolves while on campaign. Most grain rations were issued whole, meaning that soldiers had to mill and process the grain by themselves. However, grain rations also included hardtack biscuits called buccellatum, which were baked twice to remove the moisture, making them harder to spoil. These biscuits may have been ground into flour. Roman soldiers ate twice a day. The first meal, the prandium, likely required no cooking. The main meal was the cena, during which soldiers cooked and ate communally with their contubernium. Supply of water faced logistical problems. Roman military camps were typically built near water sources and soldiers were expected to collect their water for the days' march in a waterskin that was stored in the sarcina. As fresh water was not always available, water was often transported in barrels. However, this could result in the water becoming tainted, and so it was mixed with wine and vinegar to create posca, a drink which became popular among the urban poor as well as the army. During the Byzantine era, soldiers were trained in sustaining their food supplies for as long as 20 days, with many also carrying small hand mills to grind grain to make paximathia. In ancient Greece, hoplites were expected to bring foodstuffs and wine with them when going on campaigns. However, as the amount they could carry was limited, armies had to live off the land.
A study presented at the annual meeting of the American Geophysical Union in December 2006 asserted that a small-scale regional nuclear war could produce as many direct fatalities as all of World War II and disrupt the global climate for a decade or more. In a regional nuclear conflict scenario in which two opposing nations in the subtropics each used 50 Hiroshima-sized nuclear weapons (c. 15 kiloton each) on major population centers, the researchers predicted fatalities ranging from 2.6 million to 16.7 million per country. The authors of the study estimated that as much as five million tons of soot could be released, producing a cooling of several degrees over large areas of North America and Eurasia (including most of the grain-growing regions). The cooling would last for years and could be "catastrophic", according to the researchers. Either a limited or full-scale nuclear exchange could occur during an accidental nuclear war, in which the use of nuclear weapons is triggered unintentionally. Postulated triggers for this scenario have included malfunctioning early warning devices and/or targeting computers, deliberate malfeasance by rogue military commanders, consequences of an accidental straying of warplanes into enemy airspace, reactions to unannounced missile tests during tense diplomatic periods, reactions to military exercises, mistranslated or miscommunicated messages, and others. A number of these scenarios actually occurred during the Cold War, though none resulted in the use of nuclear weapons.
Sources: en.wikipedia.org
Russ Prize "for automating DNA sequencing that revolutionized biomedicine and forensic science"; the 2011 National Medal of Science, presented at a White House ceremony by President Obama in early 2013; the IEEE Medal for Innovations in Healthcare Technology in 2014, and the 2016 Ellis Island Medal of Honor. In 2017 he received the NAS Award for Chemistry in Service to Society. In 2019 Hood was awarded the IRI Medal, established by the Industrial Research Institute (IRI).
=== Surgery === Either Aetius in the sixth century CE or Persian Ali ibn Abbas al-Magusi in 990 CE conducted the first recorded thyroidectomy as a treatment for goitre. Operations remained risky and generally were not successful until the 19th century, when descriptions emerged from a number of authors including Prussian surgeon Theodor Billroth, Swiss surgeon and physiologist Theodor Kocher, American physician Charles Mayo, American surgeons William Halsted and George Crile. These descriptions provided the basis for modern thyroid surgery. Theodor Kocher went on to win the Nobel Prize in Physiology or Medicine in 1909 "for his work on the physiology, pathology and surgery of the thyroid gland".
=== Impact of Nazism === Fritz Strassmann had come to the KWIC to study under Hahn to improve his employment prospects. After the Nazi Party (NSDAP) came to power in Germany in 1933, Strassmann declined a lucrative offer of employment because it required political training and Nazi Party membership. Later, rather than become a member of a Nazi-controlled organisation, Strassmann resigned from the Society of German Chemists when it became part of the Nazi German Labour Front. As a result, he could neither work in the chemical industry nor receive his habilitation, the prerequisite for an academic position. Meitner persuaded Hahn to hire Strassmann as an assistant. Soon he would be credited as a third collaborator on the papers they produced, and would sometimes even be listed first.
=== Uniforms === Battledress - Used until the 1960s Boots, General Service Khaki drill Denison smock - Used in airborne units until the 1970s 1950 Pattern Jungle Green Dress Boots, Tropical Jungle 1960 Pattern Combat Dress - Produced in olive green and then in Disruptive Pattern Material. Boots, Directly Moulded Sole 1968 Pattern No. 8 Combat Dress - Produced in Disruptive Pattern Material. Smock Parachutist DPM Lightweight Trousers - Produced in olive green No. 9 Tropical Dress 1984 Pattern Combat Dress Boots, Combat, High
Sources: en.wikipedia.org
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.
In solution, hydrolysis of peptide bonds and oxidation of the methionine residue are the principal concerns. Oxidation converts methionine to its sulfoxide form, shifting the mass by sixteen daltons. Both processes are slowed by cold storage and by avoiding alkaline conditions.
A certificate documents what the supplier measured on a specific lot, not how a laboratory will use the material. Independent verification of identity and purity is common practice. Acceptance criteria should be defined before a batch is ordered.
It is a synthetic peptide of seven amino acids. Its backbone corresponds to a fragment of adrenocorticotropic hormone extended at the carboxyl end. The material is distributed as a lyophilized solid for laboratory use.