If you have been reading about intranasal delivery 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.
Last reviewed on 2026-04-13. Where a claim depends on a specific study, the study is described rather than over-claimed.
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.
Circulation time for the peptide is short because peptidases cleave it readily. The Pro-Gly-Pro tail is thought to slow breakdown compared with the bare ACTH fragment, but the gain appears modest. Absorption after intranasal dosing is limited, and only a fraction of a dose is expected to reach the central nervous system. Laboratory concentrations therefore sit well above levels achieved systemically, a gap that complicates translation from bench findings to clinical claims.
The mechanisms attributed to semax are inferred from animal and cell studies rather than traced to one confirmed target. The most frequently cited pathway involves increased expression of brain-derived neurotrophic factor and nerve growth factor in hippocampal and cortical tissue. Some work points to engagement of melanocortin receptors, particularly MC4, which the parent ACTH fragment can activate. Effects on dopaminergic and serotonergic signalling have also been reported. No single account explains all observed results, and the relative weight of each pathway remains unsettled.
| Property | Value | Notes |
|---|---|---|
| Primary research models | Rodent studies | Largest share of published data |
| Reported markers | BDNF and NGF expression | Measured mainly in animal tissue |
| Common administration | Intranasal | Matches the registered formulation |
| Blood residence time | Minutes | Rapid enzymatic degradation |
| Evidence quality | Small trials, limited replication | Noted repeatedly in reviews |
Claims about enhanced focus, memory, or mood in healthy people rest mostly on anecdotal reports and community discussion rather than on controlled data. It remains unclear whether any cognitive benefit observed in patients recovering from brain injury would extend to uninjured users. Dose-response relationships, long-term safety, and interactions with other drugs are not well characterized in the peer-reviewed literature. Questions about optimal route of administration and treatment duration likewise remain open.
Semax binds to melanocortin receptors and is thought to influence neuronal survival and plasticity rather than to act through the adrenal axis. Laboratory work has shown increased expression of brain-derived neurotrophic factor and nerve growth factor in treated tissue. Changes in c-Fos, a marker of neuronal activation, have also been reported. Because the peptide is rapidly degraded by peptidases, its effects are generally attributed to downstream signaling cascades rather than to sustained receptor occupancy.
Published studies are dominated by animal models of stroke, ischemia, and cognitive impairment, with a smaller number of human trials conducted in Russia. Many of the human reports are small, single-center, and published in Russian-language journals, which limits independent scrutiny. Outcome measures vary between studies and often rely on clinician-rated scales rather than objective biomarkers. Systematic reviews have noted the methodological weaknesses and called for larger, preregistered trials before firm conclusions can be drawn.
Another significant achievement of Irwin and his colleagues was to find a method of calculating the amount of energy available for fracture in terms of the asymptotic stress and displacement fields around a crack front in a linear elastic solid. This asymptotic expression for the stress field in mode I loading is related to the stress intensity factor
=== Diagnostic uses === Diagnostic qualitative PCR is applied to rapidly detect nucleic acids that are diagnostic of, for example, infectious diseases, cancer and genetic abnormalities. The introduction of qualitative PCR assays to the clinical microbiology laboratory has significantly improved the diagnosis of infectious diseases, and is deployed as a tool to detect newly emerging diseases, such as new strains of flu and coronavirus, in diagnostic tests.
For services to Agricultural Education. George Redmond Pollard, Headteacher, St. Thomas More Catholic High School, Crewe, Cheshire. For services to Education. Anne Prior, lately Courts Administrator, Lord Chancellor's Department. Professor Vincent Bruce Proudfoot, lately General Secretary, Royal Society of Edinburgh. For services to Learning. Robert Harvey Quick, Professional and Technology Superintending Grade, Ministry of Defence. Captain David Lawson Rattray, Commanding Officer, Fishery Protection Vessel Norna. Norman Turnbull Renfrew, Chairman, Perth Housing Association. For services to the Housing Association Movement and to the community in Perth. Josef Lionel Rich, Chairman, General Dental Services Committee, British Dental Association. For services to Dentistry. Shirley Jane Richards, lately General Medical Practitioner, Exeter, Devon. For services to Medicine. John Matthew Richardson, Director, Lancashire Area West Training and Enterprise Council. For services to Education and Training. Edward Anthony Richmond. For political and public service. Anna Ritchie, Member, Ancient Monuments Board for Scotland. For services to Archaeology. Michael Collingwood Roberts. For services to Energy Efficiency. Stanley Desmond Roberts. For services to Medicine. Peter Daniel Rossdale. For services to Equine Veterinary Science. Peter Segger, Chairman, MD Organic Farm Foods (Wales) Ltd. For services to Organic Horticulture. Louisa Anne Service. For services to Music and to Young People. David Shalev. For services to Architecture.
More observational evidence was published throughout the 1930s, and in 1938, Science published a paper showing that tobacco smokers live substantially shorter lives. It built a survival curve from family history records kept at the Johns Hopkins School of Hygiene and Public Health. This result was ignored or incorrectly explained away. An association between smoking tobacco and heart attacks was first mentioned in 1930; a large case–control study found a significant association in 1940, but avoided saying anything about cause, on the grounds that such a conclusion would cause controversy and doctors were not yet ready for it. Official hostility to tobacco use was widespread in Nazi Germany, where case-control studies were published in 1939 and 1943. The Institute for the Struggle against the Dangers of Tobacco (German: Wissenschaftliches Institut zur Erforschung der Tabakgefahren) was set up at the University of Jena in 1942. It was one of the first scientific institutes to discover the dangers of smoking tobacco, including the link between smoking and lung cancer. However, due to its relationship with the Nazi regime, its work was not taken seriously after the Second World War. Another was published in the Netherlands in 1948. A case-control study on lung cancer and smoking, done in 1939 by Franz Hermann Müller, had serious weaknesses in its methodology, but study design problems were better addressed in subsequent studies.
Transamination is mediated by several types of aminotransferase enzymes. An aminotransferase may be specific for an individual amino acid, or it may be able to process any member of a group of similar ones, for example the branched-chain amino acids, which comprises valine, isoleucine, and leucine. The two common types of aminotransferases are alanine aminotransferase (ALT) and aspartate aminotransferase (AST).
Sources: en.wikipedia.org
==== Philippines ==== The Chinese are being blamed after a cybersecurity company, F-Secure Labs, found a malware, NanHaiShu, which targeted the Philippines Department of Justice. It sent information in an infected machine to a server with a Chinese IP address. The malware which is considered particularly sophisticated in nature was introduced by phishing emails that were designed to look like they were coming from an authentic sources. The information sent is believed to be relating to the South China Sea legal case.
Some hemoglobinopathies seem to have given an evolutionary benefit, especially to heterozygotes, in areas where malaria is endemic. Malaria parasites infect red blood cells, but subtly disturb normal cellular function and subvert the immune response. A number of mechanisms have been proposed to explain the increased chance of survival for the carrier of an abnormal hemoglobin trait.
Amy Walter, editor of the nonpartisan The Cook Political Report, also argued that the electoral environment was inherently difficult for Harris because the top issue for voters was inflation during the Biden-Harris administration. Ronald Brownstein of The Atlantic, who spoke with members of Harris's campaign, argued that the extent of Biden's unpopularity and public discontent with the economy proved too much for Harris to overcome. Brownstein compared the election to the 1968 presidential election (when unpopular incumbent Lyndon B. Johnson withdrew from the race and Vice President Hubert Humphrey lost to Richard Nixon) and the 1980 presidential election (when unpopular incumbent Jimmy Carter lost to Ronald Reagan due to stagflation and the 1970s energy crisis). Members of Harris' campaign stated after the election that their internal polling never showed Harris ahead of Trump and they did not believe that Harris was the favorite to win the election. David Plouffe, a senior campaign advisor to Harris, claimed that even making the race competitive was a win for Harris' staff. The opportunity to elect Harris as the first female U.S. president proved to be less important to voters than issues like the economy and immigration. Results of VoteCast, as reported by Fox News, find that 13% of voters chose "the fact that Kamala Harris would be the first female president" as the single most important factor to their vote. Even so, polls have shown that voters support backing a female candidate while also acknowledging the challenges they might face on the campaign trail.
Hylomorphism is a philosophical doctrine developed by the Ancient Greek philosopher Aristotle, which conceives every physical entity or being (ousia) as a compound of matter (potency) and substantial form (act), with the generic form as immanently real within the individual. The word is a 19th-century term formed from the Greek words ὕλη (hyle: "wood, matter") and μορφή (morphē: "form"). Hylomorphic theories of physical entities have been undergoing a revival in contemporary philosophy, especially since the 2000s.
About 75% of all hermatypic corals "broadcast spawn" by releasing gametes—eggs and sperm—into the water where they meet and fertilize to spread offspring. Corals often synchronize their time of spawning. This reproductive synchrony is essential so that male and female gametes can meet. Spawning frequently takes place in the evening or at night, and can occur as infrequently as once a year, and within a window of 10–30 minutes. Synchronous spawning is very typical on the coral reef, and often, all corals spawn on the same night even when multiple species are present. Synchronous spawning may form hybrids and is perhaps involved in coral speciation.
Sources: en.wikipedia.org
== See also == Fitness (biology) – Expected reproductive success Survival of the fittest – Phrase to describe the mechanism of natural selection Conserved sequence – Similar DNA, RNA or protein sequences within genomes or among species
Skeletal muscle fiber-type phenotype in adult animals is regulated by several independent signaling pathways. These include pathways involved with the Ras/mitogen-activated protein kinase (MAPK) pathway, calcineurin, calcium/calmodulin-dependent protein kinase IV, and the peroxisome proliferator γ coactivator 1 (PGC-1). The Ras/MAPK signaling pathway links the motor neurons and signaling systems, coupling excitation and transcription regulation to promote the nerve-dependent induction of the slow program in regenerating muscle. Calcineurin, a Ca2+/calmodulin-activated phosphatase implicated in nerve activity-dependent fiber-type specification in skeletal muscle, directly controls the phosphorylation state of the transcription factor NFAT, allowing for its translocation to the nucleus and leading to the activation of slow-type muscle proteins in cooperation with myocyte enhancer factor 2 (MEF2) proteins and other regulatory proteins. Ca2+/calmodulin-dependent protein kinase activity is also upregulated by slow motor neuron activity, possibly because it amplifies the slow-type calcineurin-generated responses by promoting MEF2 transactivator functions and enhancing oxidative capacity through stimulation of mitochondrial biogenesis. Contraction-induced changes in intracellular calcium or reactive oxygen species provide signals to diverse pathways that include the MAPKs, calcineurin and calcium/calmodulin-dependent protein kinase IV to activate transcription factors that regulate gene expression and enzyme activity in skeletal muscle.
=== Nuclear fission === Einsteinium has a high rate of nuclear fission that results in a low critical mass. This mass is 9.89 kilograms for a bare sphere of 254Es, and can be lowered to 2.9 kg by adding a 30-centimeter-thick steel neutron reflector, or even to 2.26 kg with a 20-cm-thick reflector made of water. However, even this small critical mass far exceeds the total amount of einsteinium isolated so far, especially of the rare 254Es.
It is noteworthy that several cell types become polyploid during organ development or in response to infections. For example, cardiomyocytes enhance their ploidy during terminal differentiation, while viral infections can induce cell fusion, and bacterial infections may lead to the formation of multinucleated giant cells in macrophages. Reflecting on the previous discussions, it is plausible to propose that PIDD1 might be activated in certain circumstances, which positions it as a promising candidate for pharmacological strategies aimed at influencing these processes.
== History == The first flame ionization detectors were developed simultaneously and independently in 1957 by McWilliam and Dewar at Imperial Chemical Industries of Australia and New Zealand (ICIANZ, see Orica history) Central Research Laboratory, Ascot Vale, Melbourne, Australia and by Harley and Pretorius at the University of Pretoria in Pretoria, South Africa. In 1959, Perkin Elmer Corp. included a flame ionization detector in its Vapor Fractometer.
Sources: en.wikipedia.org
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.
The compound is registered as a medicine in Russia, so clinical work has concentrated there. Trials elsewhere are few and generally small. This geographic concentration is a recognized limitation in evidence reviews.
Some fraction may reach the central nervous system through olfactory pathways, and this is often cited as the rationale for the nasal route. The size of that fraction in humans is not well quantified. Blood concentrations after nasal dosing are low, which complicates measurement.
It consists mainly of animal experiments and small clinical reports, with much of the clinical material published in Russian-language journals. Large independent trials are scarce. Separating reliable effects from chance findings is consequently difficult.