A practical reference on freeze-thaw: what it is, how it behaves, what the literature reports, and where the honest uncertainties sit.
Reviewed 2026-03-04. Anything still debated is marked as such rather than presented as settled.
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.
Regulatory status varies sharply by country. Semax is registered for medical use in Russia, where it appears in formularies as a nasal solution, and it also holds registration in a small number of neighbouring states. It has no approval from the United States Food and Drug Administration or the European Medicines Agency, and it is not a scheduled controlled substance in most jurisdictions. Elsewhere it circulates mainly as laboratory material, so purity documentation comes from suppliers rather than from a national pharmacopoeia.
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.
Identity and purity are commonly assessed by reversed-phase high-performance liquid chromatography, with ultraviolet detection near 214 nanometers for the peptide backbone. Mass spectrometry, either electrospray or matrix-assisted laser desorption, confirms molecular mass and detects truncation or modification products. Amino acid analysis can verify composition. Because the sequence contains no strongly absorbing aromatic residue apart from phenylalanine, detection wavelengths are chosen carefully. Purity values above 95 percent are typical for research-grade material.
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.
| Property | Value | Notes |
|---|---|---|
| Chemical class | Synthetic heptapeptide | Analogue of the ACTH(4-10) fragment |
| Amino acid sequence | Met-Glu-His-Phe-Pro-Gly-Pro | Single-letter form MEHFPGP |
| Molecular formula | C37H51N9O10S | Free peptide, nominal mass near 814 Da |
| First registration | 1994, Russia | Nasal formulation for neurological indications |
| Typical purity grade | 95% or higher by HPLC | Research material; higher grades used as reference standards |
The proposed mechanism centres on neurotrophic signalling rather than direct receptor activation. Semax is reported to increase expression of brain-derived neurotrophic factor and nerve growth factor in several brain regions, and to shift the balance between excitatory and inhibitory neurotransmitter systems. Interaction with melanocortin receptors has been suggested because of the parent ACTH fragment. Many of these findings come from rodent studies, and the extent to which they translate to human physiology remains an open question.
Scientific literature on semax is unevenly distributed. A substantial share of published work originates from a small number of laboratories in Russia, while independent replication elsewhere is limited. Human data consist mostly of small trials with short follow-up, and several reported outcomes rely on subjective rating scales. Questions about how much intact peptide reaches the central nervous system after nasal administration, and how long it persists there, are still unresolved. The compound is best described as an active research subject rather than a settled pharmacological agent.
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.
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.
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.
=== Lifestyle and drug management === Kalra has consistently emphasised the importance of lifestyle interventions in obesity management. He has highlighted the use of traditional and indigenous activities to improve physical function in people living with obesity. He has also worked extensively on nutrition education and research. Kalra has advocated for the recognition of "mega-nutrients" such as fibre and water, which are consumed in significantly larger quantities than macronutrients. He is also a co-author of the national consensus statement on fibre intake in India. Person-centred obesity care is another major focus of his work. His publications emphasise that obesity management requires individualised strategies rather than a uniform approach. Kalra has remained closely engaged with developments in GLP-1 receptor agonists and has published periodic updates as new evidence has emerged.
The National Institutes of Health has defined a biomarker as "a characteristic that is objectively measured and evaluated as an indicator of normal biological processes, pathogenic processes, or pharmacologic responses to a therapeutic intervention." Understanding the proteome, the structure and function of each protein and the complexities of protein–protein interactions are critical for developing the most effective diagnostic techniques and disease treatments in the future. For example, proteomics is highly useful in the identification of candidate biomarkers (proteins in body fluids that are of value for diagnosis), identification of the bacterial antigens that are targeted by the immune response, and identification of possible immunohistochemistry markers of infectious or neoplastic diseases. An interesting use of proteomics is using specific protein biomarkers to diagnose disease. A number of techniques allow to test for proteins produced during a particular disease, which helps to diagnose the disease quickly. Techniques include western blot, immunohistochemical staining, enzyme linked immunosorbent assay (ELISA) or mass spectrometry. Secretomics, a subfield of proteomics that studies secreted proteins and secretion pathways using proteomic approaches, has recently emerged as an important tool for the discovery of biomarkers of disease.
=== Nazi experiments === The harmful effects of X-rays were recognized during the Nazism era. The function of the gonads (ovaries or testicles) was destroyed by ionizing radiation, leading to infertility. In July 1942, Heinrich Himmler (1900-1945) decided to conduct forced sterilization experiments at the Auschwitz-Birkenau concentration camp, which were carried out by Horst Schumann (1906-1983), previously a doctor in Aktion T4. Each test victim had to stand between two X-ray machines, which were arranged in such a way that the test victim had just enough space between them. Opposite the x-ray machines was a booth with lead walls and a small window. From the booth, Schumann could direct X-rays at the test victims' sexual organs without endangering himself. Human radiation castration experiments were also conducted in concentration camps under the direction of Viktor Brack (1904-1948). As part of the "Law for the Prevention of Hereditary Diseases," people were often subjected to radiation castration during interrogations without their knowledge. Approximately 150 radiologists from hospitals throughout Germany participated in the forced castration of approximately 7,200 people using X-rays or radium.
== Honors and awards == 2005 – HUPO Award 2006 – Buchner Medal 2008 – In recognition of his contribution to the field of protein sciences and proteomics the Association of Biomolecular Resource Facilities (ABRF) selected him for the ABRF 2008 Award. 2010 – Herbert A. Sober Lectureship 2010 – Otto Naegeli Prize 2012 – Thomson Medal Award 2014 – he became a member of the German Academy of Sciences Leopoldina. 2015 – ranked #1 on the 2015 list of "most influential people in the analytical sciences" (by the Analytical Scientist) 2018 – Bijvoet Medal of the Bijvoet Center for Biomolecular Research of Utrecht University 2020 – Marcel Benoist Prize 2026 – Canada Gairdner International Award
=== Rail freight === South Africa has a longer rail network than all other Sub-Saharan African countries combined, at a total length of 23,000 km. Its network also features most of the double track rail in the region. State-owned Transnet Freight Rail is one of the largest players in the region. Approximately 15% of SA's land freight moves by rail. As of 2026, South Africa has three "Bulk Mineral Rail Corridors", which are dedicated heavy haul lines for export minerals. These routes, which total 2,241km, are:
Sources: en.wikipedia.org
FARC dissidents are a group formerly part of the Revolutionary Armed Forces of Colombia, who have refused to lay down their arms after the FARC-government peace treaty came into effect in 2016. The dissidents number some 1,200 armed combatants, with an unknown number of civilian militia supporting them. FARC dissidents have become "an increasing headache" for the Colombian armed forces, as they have to fight them, the EPL, ELN, and Clan del Golfo at the same time. FARC dissidents are led by former mid-level commanders such as alias "Gentil Duarte," alias "Euclides Mora," alias "John 40," alias "Giovanny Chuspas," and alias "Julián Chollo." FARC dissidents have been responsible for several attacks on Colombian armed forces. These fighters are believed to be heavily involved in the production and sale of cocaine. Dissidents of FARC's 1st Front are located in the eastern plains of Colombia. John 40 and their dissident 43rd Front moved into the Amazonas state of western Venezuela. Venezuela has served as the primary location for many FARC dissidents. On July 15, 2018, the Colombian and Peruvian governments launched a joint military effort, known as Operation Armageddon, to combat FARC dissidents. Peru issued a 60-day state of emergency in the Putumayo Province, an area bordering both Colombia and Ecuador. On the first day alone, more than 50 individuals were arrested in the operation, while four cocaine labs were dismantled. The group has attempted to recruit locals in the Putumayo Province in Peru to take up their cause.
Partial-thickness: The more common type involves removing a thin layer of skin from a healthy part of the body (the donor section). Full-thickness: Involves excising a defined area of skin, with a depth of excision down to the fat. The full thickness portion of skin is then placed at the recipient site. A full-thickness skin graft is more risky, in terms of the body accepting the skin, yet it leaves only a scar line on the donor section, similar to a Cesarean-section scar. In the case of full-thickness skin grafts, the donor section will often heal much more quickly than the injury and causes less pain than a partial-thickness skin graft. A partial thickness donor site must heal by re-epithelialization which can be painful and take an extensive length of time.
Wet market is a regional English term for a marketplace, also called a public market or a traditional market, that sells fresh foods, such as meat, fish, and produce, and other consumption-oriented perishable goods in a non-supermarket setting, as distinguished from "dry markets" that sell durable goods, such as fabrics, kitchenwares and electronics. The term was popularised by the Singaporean government in the 1970s and did not originate in mainland China, where such markets are called "farmers' markets" or "produce markets". It was little known in English before the COVID-19 pandemic, when coverage of the Huanan Seafood Wholesale Market in Wuhan brought it to global prominence. Such markets include a wide variety of types, such as farmers' markets, fish markets, and wildlife markets. Not all of them sell live animals, but the term is sometimes used to signify a live animal market in which vendors slaughter animals upon customer purchase, such as is done with poultry in Hong Kong. Such markets are common in many parts of the world, notably in China, Southeast Asia, and South Asia. They often play critical roles in urban food security due to factors of pricing, freshness of food, social interaction, and local cultures. Despite their importance in local food systems and livelihoods, they often lack essential food safety infrastructure, such as cold chains, standardized hygiene practices, regular inspection, and product traceability.
Eleven months after reimplantation, a viable intrauterine pregnancy was confirmed, which resulted in the first such live birth – a girl named Tamara. Therapeutic hypothermia, e.g. during heart surgery on a "cold" heart (generated by cold perfusion without any ice formation) allows for much longer operations and improves recovery rates for patients.
Sources: en.wikipedia.org
== Applications == Affibody molecules can be used for protein purification, enzyme inhibition, research reagents for protein capture and detection, diagnostic imaging and targeted therapy. The second generation of Affibody molecule, ABY-025, binds selectively to HER2 receptors with picomolar affinity. These Affibody molecules are in clinical development for tumor diagnosis. Anti-HER2 Affibody molecule, fused with albumin binding domain (ABD), denoted as ABY-027, labeled with Lutetium-177 provided reduction of renal and hepatic uptake of radioactivity in mice xenografts.. Further preclinical research evaluated an optimised version of the same ABD-fused Affibody, reporting an improved therapeutic effect in combination with trastuzumab. In October 2025, a refined variant of the ABD-fused Affibody molecule targeting HER2, radiolabelled with Lutetium-177, entered clinical trials to assess its safety, biodistribution and tolerability in patients with metastatic breast cancer. Recently, anti-ZEGFR Affibody ZEGFR:2377 labeled with technetium-99m was successfully used to visualize ZEGR expressing tumor in mice xenograft also.
=== Funding and revenue === In 2023, Breakthrough T1D raised $224 million; of this, 78% went toward programs including research funding, 15% was spent on fundraising, and 7% was spent on administrative costs. Cumulatively, Breakthrough T1D was funding approximately $568 million in T1D research projects worldwide in 2018.
At this time, the Selous Scouts comprised about 120 personnel and all of its officers were white. Black soldiers were offered bonuses that almost doubled their salary if they agreed to serve with the Selous Scouts. The unit was named after the British explorer Frederick Selous (1851–1917) and its motto was pamwe chete—a Shona phrase meaning "all together", "together only" or "forward together". The charter of the Selous Scouts directed them to "the clandestine elimination of terrorism both within and without the country". The name Selous Scouts had previously been attached to the Rhodesian Armoured Car Regiment of the Federal Army of Rhodesia and Nyasaland. The South African Police's Special Branch provided funding for the Selous Scouts. This formed part of the South African Government's extensive support for the Rhodesian counterinsurgency effort. Many South African Defence Force personnel served in the Selous Scouts between 1973 and 1979, including during operations in Rhodesia, Mozambique and Zambia. After the South African Government publicly withdrew the South African Police units which had been deployed to Rhodesia in 1975 SADF personnel continued to serve with the Selous Scouts. A witness who testified at the post-Apartheid South African Truth and Reconciliation Commission stated that the Selous Scouts were covertly funded by the South African Police and South African police officers also served in the unit.
Sources: en.wikipedia.org
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.
No. The peptide is synthetic, although it is modelled on a fragment of a naturally occurring hormone. ACTH(4-10) is generated when ACTH is cleaved, but the Pro-Gly-Pro extension is not a known endogenous sequence. It is therefore a designed analogue rather than a natural metabolite.
The label reflects reported effects on attention, memory and recovery after neurological injury in regional clinical reports. Those reports are mostly small and have not been widely replicated outside the region. The classification is descriptive and does not imply a single defined mechanism.
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.