A practical reference on neurotrophic factor: what it is, how it behaves, what the literature reports, and where the honest uncertainties sit.
Reviewed 2025-12-26. Anything still debated is marked as such rather than presented as settled.
Semax is a synthetic heptapeptide with the sequence Met-Glu-His-Phe-Pro-Gly-Pro. Its chain combines the first seven residues of corticotropin with a C-terminal proline-glycine-proline extension, a modification intended to slow enzymatic breakdown. The free peptide has a molecular mass near 813.9 daltons. It belongs to the class of ACTH-derived fragments studied for central nervous system activity rather than for adrenal steroid stimulation. This structural relationship to a natural hormone fragment is the usual starting point for describing the compound in the literature.
Development took place during the 1980s at institutes of the Russian Academy of Sciences, where peptide fragments of ACTH were screened for cognitive and neuroprotective effects. The compound received regulatory approval in Russia as a nasal preparation, marketed for conditions such as ischemic stroke, transient ischemic attacks, and optic nerve disorders. Registration in other countries has not followed. Most published clinical reports originate from a small number of Russian research groups, and independent replication outside that setting remains limited. The regulatory status therefore differs sharply between Russia and the rest of the world.
Laboratory work points toward modulation of neurotrophic signaling, particularly expression of brain-derived neurotrophic factor and nerve growth factor in hippocampal tissue. Studies also describe effects on monoamine turnover, inflammatory mediators, and oxidative markers. These observations come mainly from animal models and cultured cells, so the causal chain in humans is not firmly established. Whether the reported molecular changes translate into measurable clinical benefit is an open question. Reviews generally present the mechanism as plausible rather than demonstrated.
Solid semax is typically supplied as a lyophilised powder that is hygroscopic and sensitive to moisture, light, and repeated temperature cycling. Long-term storage of the dry peptide is generally recommended at approximately -20 degrees Celsius, while shorter working periods may use refrigeration at 2 to 8 degrees Celsius. Vials should remain tightly closed and desiccated when brought to room temperature, because condensation can damage the material before it is weighed. Dividing a batch into aliquots is preferable to thawing one container repeatedly.
Dissolution is normally performed in water, phosphate-buffered saline, or normal saline, since the peptide is freely soluble in aqueous media and is rarely handled with strong organic solvents. Solution pH should be kept near neutral, because extreme acidity or alkalinity accelerates backbone hydrolysis and encourages oxidation of the methionine side chain. Once dissolved, the material is less stable than the dry powder and is commonly divided into single-use portions and frozen. Buffers containing primary amines, such as Tris, are often avoided because of possible side reactions.
| Property | Value | Notes |
|---|---|---|
| Sequence | Met-Glu-His-Phe-Pro-Gly-Pro | Heptapeptide; ACTH(4-10) analog extended at C-terminus |
| Molecular mass | ~813.9 Da | Free peptide, unmodified |
| Appearance | White to off-white powder | Typical lyophilized solid |
| Solubility | Soluble in water and saline | Also soluble in common aqueous buffers |
| Storage (solid) | -20 °C, desiccated | Protect from moisture and repeated thawing |
Terminology around the compound varies by source. It appears in catalogues and papers as Semax, as the heptapeptide ACTH(4-7)-Pro-Gly-Pro, and under various alphanumeric laboratory codes used by individual suppliers. These names refer to the same sequence but may imply different salt forms, purity grades, or counter-ions. Peptide databases usually list the free base mass, while product descriptions sometimes report acetate or trifluoroacetate salts with a different formula weight. Because naming conventions for research peptides are not standardised across vendors, checking the declared sequence and measured mass is more reliable than relying on a trade name alone.
Semax is a synthetic heptapeptide with the sequence Met-Glu-His-Phe-Pro-Gly-Pro. Its design combines the ACTH(4-7) core fragment with a C-terminal Pro-Gly-Pro extension, a modification intended to improve stability and prolong activity. The molecule is hydrophilic, carries no lipid chains or glycosylation, and has a theoretical mass just over 810 daltons in its free form. All seven residues are proteinogenic amino acids, so no non-natural building blocks appear in the backbone. A free N-terminal methionine and C-terminal proline define the unmodified parent peptide.
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.
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.
==== Chlorine dioxide ==== Chlorine dioxide can come from tablets or be created by mixing two chemicals together. It is more effective than iodine or chlorine against giardia, and although it has only low to moderate effectiveness against cryptosporidium, iodine and chlorine are ineffective against this protozoan. The cost of chlorine dioxide treatment is higher than the cost of iodine treatment.
Roberto Gottardo of the diocese of Turin stated that for the first time they had released high-definition images of the Shroud that can be used on tablet computers and can be magnified to show details not visible to the naked eye. As this rare exposition took place, Pope Francis issued a carefully worded statement which urged the faithful to contemplate the Shroud with awe but, like most of his predecessors, he "stopped firmly short of asserting its authenticity". The Shroud was again placed on display in the cathedral in Turin from 19 April 2015 to 24 June 2015. There was no charge to view it, but an appointment was required.
The kanji phrase 銀杏 ginkyō meaning 'silver apricot' had been attested in Chinese herbology literature such as 日用本草 (Daily Use Materia Medica) (1329) and Compendium of Materia Medica 本草綱目 published in 1578; 銀杏 was particular terminology used during the Song dynasty for tributary reasons in place of the then contemporary 鴨脚 ("duckfeet", from its leaves) in northeast China where it commonly grew. The older Chinese name for this plant is 銀果, meaning "silver fruit", pronounced yínguǒ in Mandarin or ngan-gwo in Cantonese, the current commonly used names are 白果 (bái guǒ) meaning 'white fruit'. Despite its spelling based on this complicated etymology, "ginkgo" is usually pronounced , which has given rise to the common alternative spelling "gingko". The spelling pronunciation is also documented in some dictionaries.
Typically QSAR models derived from non linear machine learning is seen as a "black box", which fails to guide medicinal chemists. Recently there is a relatively new concept of matched molecular pair analysis or prediction driven MMPA which is coupled with QSAR model in order to identify activity cliffs.
Sources: en.wikipedia.org
For the advanced economies, there is an unmistakable need to restore fiscal sustainability through credible consolidation [deficit reduction] plans. At the same time we know that slamming on the brakes too quickly will hurt the recovery and worsen job prospects. So fiscal adjustment must resolve the conundrum of being neither too fast nor too slow. Shaping a Goldilocks fiscal consolidation is all about timing. What is needed is a dual focus on medium-term consolidation and short-term support for growth and jobs. That may sound contradictory, but the two are mutually reinforcing. Decisions on future consolidation, tackling the issues that will bring sustained fiscal improvement, create space in the near term for policies that support growth and jobs.
The quantitative "reading" is usually based on detection of intensity of transmitted light by spectrophotometry, which involves quantitation of transmission of some specific wavelength of light through the liquid (as well as the transparent bottom of the well in the multiple-well plate format). The sensitivity of detection depends on amplification of the signal during the analytic reactions. Since enzyme reactions are very well known amplification processes, the signal is generated by enzymes which are linked to the detection reagents in fixed proportions to allow accurate quantification, and thus the name "enzyme-linked". The analyte is also called the ligand because it will specifically bind or ligate to a detection reagent, thus ELISA falls under the bigger category of ligand binding assays. The ligand-specific binding reagent is "immobilized", i.e., usually coated and dried onto the transparent bottom and sometimes also side wall of a well (the stationary "solid phase"/"solid substrate" here as opposed to solid microparticle/beads that can be washed away), which is usually constructed as a multiple-well plate known as the "ELISA plate". Conventionally, like other forms of immunoassays, the specificity of antigen-antibody type reaction is used because it is easy to raise an antibody specifically against an antigen in bulk as a reagent. Alternatively, if the analyte itself is an antibody, its target antigen can be used as the binding reagent.
Porous glass is glass that includes pores, usually in the nanometre- or micrometre-range, commonly prepared by one of the following processes: through metastable phase separation in borosilicate glasses (such as in their system SiO2-B2O3-Na2O), followed by liquid extraction of one of the formed phases; through the sol-gel process; or simply by sintering glass powder. The specific properties and commercial availability of porous glass make it one of the most extensively researched and characterized amorphous solids. Due to the possibility of modeling the microstructure, porous glasses have a high potential as a model system. They show a high chemical, thermal and mechanical resistance, which results from a rigid and incompressible silica network. They can be produced in high quality and with pore sizes ranging from 1 nm up to any desired value. An easy functionalization of the inner surface opens a wide field of applications for porous glasses. A further special advantage of porous glasses compared to other porous materials, is that they can be made not only as powder or granulate, but also as larger pieces in almost any user defined shape and texture.
==== GAR transformylase ==== PurN GAR transformylase is found in eukaryotes and prokaryotes. However, a second GAR transformylase, PurT GAR transformylase has been identified in E. coli. While the two enzymes have no sequence conservation and require different formyl donors, the specific activity and Km for GAR are the same in both PurT and PurN GAR transformylase.
The densities of the two phases must also be sufficiently different so that the phases will move past each other in the column. Many DCCC solvent systems contain both chloroform and water. The solvent system used in the seminal publication was made from chloroform, acetic acid, and aqueous 0.1 M hydrochloric acid. Many subsequent solvents systems were made with chloroform, methanol, and water which is sometimes represented as a ChMWat solvent system. Solvent systems formulated with ''n''-butanol, water and a modifier such as acetic acid, pyridine or n-propanol have also enjoyed some success in DCCC. In some cases, non-aqueous biphasic solvent systems such as acetonitrile and methanol have been utilized. The main difference between DCCC and other types of countercurrent chromatography techniques is that there is no vigorous mixing of phases to enhance the mass transfer of compounds that allows them to distribute between the two phases. In 1951 Kies and Davis described an apparatus similar to the DCCC. They created a series of open tubes that were arranged in a cascade to either drip a more dense phase through a less dense stationary phase or, conversely, a less dense phase could be introduced into the bottom of the tube to dribble through the more dense phase. In 1954, a fractionation column was introduced by Kepes the resembled a CCC column divided into chambers with perforated plastic disks. Similar DCCC-type instruments have been created by A. E. Kostanyan and collaborators which employ vertical columns that are divided into partitions with porous disks.
Sources: en.wikipedia.org
Your structure will completely collapse across the entire continent." Guyana: President Irfaan Ali stated that Guyana has activated its security plan, declaring that "the Guyana Defence Force and the security forces are monitoring the situation and Guyanese should be reassured that the government is working to ensure the safety and security of our citizens." Paraguay: The Ministry of Foreign Affairs issued a statement reaffirming the country's "historic commitment to the peaceful resolution of international disputes". It also referred to Maduro as the "leader" of the Cartel of the Suns (declared a terrorist organization by the Paraguayan government) and stated that his continued hold on power posed a threat to the region. President Santiago Peña later approved the strikes, stating that "it can only bring good news". Peru: President José Jerí welcomed the intervention, stating that "Venezuela is beginning a new era of democracy and freedom." Similarly, he mentioned that "many families will be able to reunite in their country, so we will facilitate their immediate return regardless of their immigration status." Uruguay: The Ministry of Foreign Relations condemned the US intervention in Venezuela, calling on the US to adhere to the UN Charter and respect Venezuela's sovereignty.
Heroin is generally a preferred product for smuggling and distribution—over unrefined opium due to the cost-effectiveness and increased efficacy of heroin. Because of the high cost per volume, heroin is easily smuggled. A US quarter-sized (2.5 cm) cylindrical vial can contain hundreds of doses. From the 1930s to the early 1970s, the so-called French Connection supplied the majority of US demand. Allegedly, during the Vietnam War, drug lords such as Ike Atkinson used to smuggle hundreds of kilograms of heroin to the US in coffins of dead American soldiers (see Cadaver Connection). Since that time it has become more difficult for drugs to be imported into the US than it had been in previous decades, but that does not stop the heroin smugglers from getting their product across US borders. Purity levels vary greatly by region with Northeastern cities having the most pure heroin in the United States. On 17 October 2018 police in Genoa, Italy discovered 270 kg (600 lb) of heroin hidden in a ship coming from the Iranian southern port of Bandar Abbas. The ship had already passed and stopped at Hamburg in Germany and Valencia in Spain. Penalties for smuggling heroin or morphine are often harsh in most countries. Some countries will readily hand down a death sentence (e.g. Singapore) or life in prison for the illegal smuggling of heroin or morphine, which are both internationally Schedule I drugs under the Single Convention on Narcotic Drugs. In May 2021, Romania seized 1.4 tonnes of heroin at Constanța port of a shipment from Iran that was headed for Western Europe.
Tier 1: Tier 1 assembly is the standard Golden Gate assembly, and genes are assembled from their components parts (DNA parts coding for genetic elements like UTRs, promoters, ribosome binding sites or terminator sequences). Flanking the insertion site of the tier 1 destination vectors are a pair of inward cutting BpiI restriction sites. This allows these plasmids to be used as entry vectors for tier two destination vectors. Tier 2: Tier 2 assembly involves further assembling the genes assembled in tier 1 assembly into multi-gene constructs. If there is a need for further, higher tier assembly, inward cutting BsaI restriction sites can be added to flank the insertion sites. These vectors can then be used as entry vectors for higher tier constructs. Each assembly tier alternates the use of BsaI and BpiI restriction sites to minimise the number of forbidden sites, and sequential assembly for each tier is achieved by following the Golden Gate plasmid design. Overall, the MoClo standard allows for the assembly of a construct that contains multiple transcription units, all assembled from different DNA parts, by a series of one-pot Golden Gate reactions. However, one drawback of the MoClo standard is that it requires the use of 'dummy parts' with no biological function, if the final construct requires less than four component parts. The Golden Braid standard on the other hand introduced a pairwise Golden Gate assembly standard. The Golden Braid standard uses the same tiered assembly as MoClo, but each tier only involves the assembly of two DNA fragments, i.e. a pairwise approach.
In addition to its well-explored interactions with NMDA receptors, PCP has also been shown to inhibit dopamine reuptake, and thereby leads to increased extracellular levels of dopamine and hence increased dopaminergic neurotransmission. However, PCP has little affinity for the human monoamine transporters, including the dopamine transporter (DAT). Instead, its inhibition of monoamine reuptake may be mediated by interactions with allosteric sites on the monoamine transporters. PCP is notably a high-affinity ligand of the PCP site 2 (Ki = 154 nM), a not-well-characterized site associated with monoamine reuptake inhibition. Studies on rats indicate that PCP interacts indirectly with opioid receptors (endorphin and enkephalin) to produce analgesia. A binding study assessed PCP at 56 sites including neurotransmitter receptors and transporters and found that PCP had Ki values of >10,000 nM at all sites except the dizocilpine (MK-801) site of the NMDA receptor (Ki = 59 nM), the σ2 receptor (PC12) (Ki = 136 nM), and the serotonin transporter (Ki = 2,234 nM). The study notably found Ki values of >10,000 nM for the D2 receptor, the opioid receptors, the σ1 receptor, and the dopamine and norepinephrine transporters. These results suggest that PCP is a highly selective ligand of the NMDAR and σ2 receptor. However, PCP may also interact with allosteric sites on the monoamine transporters to produce inhibition of monoamine reuptake.
Sources: en.wikipedia.org
Semax is a synthetic seven-amino-acid peptide derived from a fragment of corticotropin. It is used in Russia as a nasal preparation, while elsewhere it is studied as a research compound. It is not approved as a medicine in most countries.
Its sequence corresponds to the 4-10 region of corticotropin extended by three residues. This fragment lacks the region responsible for adrenal steroid release, so it is explored for neural rather than hormonal effects. The relationship explains the compound's classification among ACTH-derived peptides.
It holds approval in Russia for several neurological indications as a nasal spray or drop formulation. Regulatory agencies in the United States and the European Union have not approved it. Products sold elsewhere are generally labeled for research use only.
Dry powder is usually kept at about -20 degrees Celsius for long-term storage and at 2 to 8 degrees Celsius for short working periods. Containers should stay sealed and protected from light and moisture to limit degradation.