A practical reference on Lyophilisation: what it is, how it behaves, what the literature reports, and where the honest uncertainties sit.
Reviewed 2026-05-29. Anything still debated is marked as such rather than presented as settled.
Clinical evidence comes mainly from small studies conducted in Russia, several of which were open-label or lacked robust blinding. Reported outcomes include lower anxiety scores, changes in attention measures, and effects on asthenic states following illness. Sample sizes are typically in the tens of participants, and independent replication outside the region is scarce. Reviews published in English generally note the limited methodological quality of the underlying trials. Whether the compound produces clinically meaningful effects under rigorous conditions remains unresolved.
Proposed mechanisms center on modulation of the GABA system, but no single molecular target has been confirmed. Rodent studies report changes in GABA-A receptor expression and in the turnover of serotonin, dopamine, and norepinephrine in several brain regions. Increases in brain-derived neurotrophic factor and its receptor have also been described after repeated administration. These findings come largely from animal models, and the degree to which they describe human neurochemistry remains an open question. The mechanism is best characterized as multi-system and not fully resolved.
Pharmacokinetic data are limited. Like most short peptides, Selank is vulnerable to plasma and tissue peptidases, and its measured half-life in circulation is short, on a minutes scale. The Pro-Gly-Pro tail slows this degradation but does not eliminate it. Intranasal administration is the route described in most reports, with absorption through the nasal mucosa and a hypothesized path into the central nervous system that avoids the blood-brain barrier. Direct measurements of human brain exposure are unavailable, so distribution claims rest on inference from animal work.
Tuftsin, the parent structure, is a naturally occurring immunomodulatory tetrapeptide released from the Fc region of immunoglobulin G by spleen enzymes. Selank extends this four-residue sequence with three additional amino acids. The stated rationale is that the added tail slows enzymatic breakdown and may influence receptor interactions. How the full heptapeptide behaves at the molecular level is not firmly established, and proposed mechanisms often involve indirect modulation of neurotransmitter or immune signaling rather than a single defined target.
Selank is a synthetic heptapeptide developed in Russia. Its sequence is Thr-Lys-Pro-Arg-Pro-Gly-Pro, a seven-residue chain built around the natural tetrapeptide tuftsin. Researchers at the Institute of Molecular Genetics of the Russian Academy of Sciences first described the compound in the mid-1990s. The design combined the tuftsin core with an added Pro-Gly-Pro tail, a modification intended to extend the molecule's stability in biological fluids. Published work on the peptide has appeared mainly in Russian-language journals.
Reported activity for Selank centers on anxiolytic and nootropic effects. Russian clinical reports describe use in anxiety and in cognitive or attention-related complaints. Most of this evidence comes from studies conducted by the same research groups that developed the peptide. Independent replication in other countries remains limited, and no major Western regulatory agency has approved the compound for any indication. The gap between local reports and external verification is a recurring point in discussions of the peptide.
| Property | Value | Notes |
|---|---|---|
| Route studied | Intranasal | Predominant route in published reports |
| Circulation stability | Short, minutes scale | Peptidases cleave it; the tail slows the process |
| Analytical method | RP-HPLC with mass spectrometry | Used for identity and purity assessment |
| Reported outcome domains | Anxiety and cognitive measures | Derived from small, mostly regional trials |
| Regulatory status | Marketed in Russia | Availability outside that market is limited |
Identity and purity are usually assessed by reversed-phase high-performance liquid chromatography, with mass spectrometry used to confirm molecular mass and sequence information. Amino acid analysis and peptide mapping may supplement these methods. Certified reference standards are scarce, and many commercial lots are sold as research chemicals without a pharmacopoeial monograph. Regulatory treatment differs by country: Selank is a registered prescription medicine in Russia, while in the European Union and the United States it is not an approved drug and may fall under research-chemical or unapproved-product frameworks.
Selank is a hydrophilic peptide and dissolves readily in water and in aqueous buffers. The lyophilised powder is typically a white to off-white solid. Because short peptides are prone to hydrolysis and oxidation, handling benefits from limiting exposure to heat, moisture and strong light. Working solutions are commonly prepared in sterile water or saline, and repeated freeze-thaw cycles are avoided to reduce aggregation and loss of activity. These practices reflect general laboratory convention rather than published stability specifications.
Dry powder is normally held at -20 degrees Celsius or lower, in a sealed container with desiccant and protection from light. Reconstituted solutions are usually kept at 2 to 8 degrees Celsius for short periods and frozen for longer ones. Proline residues at several positions are generally associated with some resistance to peptidase attack, but chemical stability still declines at neutral to alkaline pH and at elevated temperature. Exact shelf-life figures are product-specific and are not standardised across suppliers.
Once dissolved, the peptide is markedly less stable than the dry powder. Aqueous solutions are subject to backbone hydrolysis and to microbial growth when they are handled without sterile technique. Buffered solutions near neutral pH are common for short-term laboratory work, while acidic conditions are sometimes used to improve solubility. Analytical laboratories generally prepare working solutions fresh rather than storing them, and a residual water film left in a reopened vial can seed degradation even when the container appears dry.
Reversed-phase high-performance liquid chromatography is the standard technique for estimating peptide purity. The result is a peak-area percentage, which describes how much of the detected material elutes as the main peak in one run. Mass spectrometry confirms the molecular mass and can reveal truncated, adducted, or otherwise modified species. Amino acid analysis or tandem mass spectrometry can address sequence fidelity when identity is in doubt. None of these measurements, taken alone, establishes that a sample is fit for any specific purpose.
Lyophilized selank is normally supplied as a dry powder and is considered stable for extended periods when kept cold and dry. Moisture uptake is the main practical threat, because absorbed water promotes both hydrolysis and aggregation in the solid state. Vials are usually warmed to room temperature before opening so that condensation does not form on the powder. Supplier documentation commonly specifies -20 °C for routine storage, with -80 °C used for material intended to be archived for years.
Selank is studied chiefly as an animal-model anxiolytic with proposed secondary effects on memory and immune signaling. Reported mechanisms include modulation of the GABA-A receptor complex, inhibition of enkephalin-degrading enzymes, and shifts in monoamine turnover within limbic structures. Some experiments describe increased expression of brain-derived neurotrophic factor in the hippocampus after repeated dosing. No single molecular target has been confirmed, and the peptide does not bind any receptor with the selectivity typical of a conventional small-molecule drug. Mechanism therefore remains a set of hypotheses rather than an established pathway.
Laboratory work relies on standard behavioral paradigms. Rodents are tested in the elevated plus maze, open field, and passive avoidance tasks, with outcomes compared against diazepam or vehicle controls. Intranasal dosing is used most often because it bypasses first-pass metabolism, though intraperitoneal and intravenous routes also appear in published protocols. Biochemical endpoints include tissue BDNF concentrations, cytokine levels, and monoamine metabolites. Human data are limited to small Russian trials reporting reduced anxiety scores; most were not prospectively registered, and few employed independent outcome assessment.
Identity and purity of selank are established with reversed-phase high-performance liquid chromatography coupled to mass spectrometry. The peptide elutes from C18 columns with acetonitrile gradients in water containing trifluoroacetic acid or formic acid, and detection is usually performed by ultraviolet absorbance near 214 nm. Electrospray ionization in positive mode gives a doubly protonated ion near m/z 377, consistent with a mass of about 752 Da. Amino acid analysis or tandem mass spectrometry of fragment ions confirms the sequence. Because the molecule has no aromatic residues, it lacks a usable 280 nm chromophore, so low-wavelength detection or mass spectrometry is required.
Peptide bonds in selank are susceptible to hydrolysis under strongly acidic or basic conditions, and the terminal proline residues are vulnerable to exopeptidase activity in biological samples. Lyophilized powder stored dry at -20 °C typically remains stable for extended periods, whereas aqueous solutions degrade faster and may lose measurable purity within days to weeks depending on pH, temperature, and microbial load. Repeated freeze-thaw cycles promote aggregation and adsorption to container surfaces. For analytical work, solutions are usually prepared fresh, kept cold, and used within a single working day.
Handling follows standard practice for research peptides. Material is weighed in a low-humidity environment because the powder absorbs atmospheric moisture. Purity is reported as the percentage area of the main peak in a chromatogram, with specifications commonly set at 95 percent or higher; values below that threshold indicate the presence of truncated or modified species. Residual trifluoroacetate from purification is often present and may affect mass balance. Certificates of analysis should state the analytical method, the column and gradient used, and the lot-specific retention time so that results can be compared across suppliers.
=== Molecular classification === As with bacterial classification, identification of bacteria is increasingly using molecular methods, and mass spectroscopy. Most bacteria have not been characterised and there are many species that cannot be grown in the laboratory. Diagnostics using DNA-based tools, such as polymerase chain reaction, are increasingly popular due to their specificity and speed, compared to culture-based methods. These methods also allow the detection and identification of "viable but nonculturable" cells that are metabolically active but non-dividing. The main way to characterize and classify these bacteria is to isolate their DNA from environmental samples and mass-sequence them. This approach has identified thousands, if not millions of candidate species. Based on some estimates, more than 43,000 species of bacteria have been described, but attempts to estimate the true number of bacterial diversity have ranged from 107 to 109 total species—and even these diverse estimates may be off by many orders of magnitude.
SEC is used primarily for the analysis of large molecules such as proteins or polymers. SEC works by trapping smaller molecules in the pores of the adsorbent ("stationary phase"). This process is usually performed within a column, which typically consists of a hollow tube tightly packed with micron-scale polymer beads containing pores of different sizes. These pores may be depressions on the surface or channels through the bead. As the solution travels down the column some particles enter into the pores. Larger particles cannot enter into as many pores. The larger the particles, the faster the elution. The larger molecules simply pass by the pores because those molecules are too large to enter the pores. Larger molecules therefore flow through the column more quickly than smaller molecules, that is, the smaller the molecule, the longer the retention time. One requirement for SEC is that the analyte does not interact with the surface of the stationary phases, with differences in elution time between analytes ideally being based solely on the solute volume the analytes can enter, rather than chemical or electrostatic interactions with the stationary phases. Thus, a small molecule that can penetrate every region of the stationary phase pore system can enter a total volume equal to the sum of the entire pore volume and the interparticle volume. This small molecule elutes late (after the molecule has penetrated all of the pore- and interparticle volume—approximately 80% of the column volume).
== ISO 8000 – ISO 8999 == ISO 8000 Data quality ISO 8002:1986 Mechanical vibrations – Land vehicles – Method for reporting measured data ISO 8015:2011 Geometrical product specifications (GPS) – Fundamentals – Concepts, principles and rules ISO 8041:2005 Human response to vibration - Measuring instrumentation ISO 8041-1:2017 Part 1: General purpose vibration meters ISO 8042:1988 Shock and vibration measurements – Characteristics to be specified for seismic pick-ups ISO 8044:2015 Corrosion of metals and alloys – Basic terms and definitions ISO 8048:1984 Technical drawings – Construction drawings – Representation of views, sections and cuts ISO 8049:2016 Ferronickel shot - Sampling for analysis ISO 8050:1988 Ferronickel ingots or pieces - Sampling for analysis ISO 8062 Geometrical product specifications (GPS) - Dimensional and geometrical tolerances for moulded parts ISO 8062-1:2007 Part 1: Vocabulary ISO/TS 8062-2:2013 Part 2: Rules ISO 8062-3:2007 Part 3: General dimensional and geometrical tolerances and machining allowances for castings ISO 8062-4:2017 Part 4: General tolerances for castings using profile tolerancing in a general datum system ISO 8063 Information processing – Data interchange on 6,30 mm (0.25 in) wide magnetic tape cartridge using IMFM recording at 252 ftpmm (6 400 ftpi) ISO 8063-1:1986 Part 1: Mechanical, physical and magnetic properties ISO 8063-2:1986 Part 2: Track format and method of recording for data interchange in start/stop mode ISO 8064:1985 Information processing – Reels for 12,7 mm (0,5 in) wide magnetic tapes – Sizes 16, 18 and 22 ISO/IEC 8072:1996 Information technology – Open systems interconnection – Transport service definition ISO/IEC 8073:1997 Information technology – Open Systems Interconnection – Protocol for providing the connection-mode transport service ISO 8088:1994 Equipment for olive cultivation and olive oil production – Vocabulary ISO 8090:1990 Cycles – Terminology ISO 8107:1993 Nuclear power plants - Maintainability - Terminology ISO 8109:1990 Banking and related financial services – Securities – Format of Eurobonds ISO 8114:1990 Textile machinery and accessories – Spindles for ring-spinning and doubling machines – List of equivalent terms ISO 8116 Textile machinery and accessories – Beams for winding ISO 8116-1:1995 Part 1: General vocabulary ISO 8119 Textile machinery and accessories – Needles for knitting machines – Terminology ISO 8119-1:1989 Part 1: Latch-type needles ISO 8119-2:1989 Part 2: Bearded needles ISO 8119-3:1992 Part 3: Compound needles ISO/IEC 81346: Industrial systems, installations and equipment and industrial products – structuring principles and reference designations ISO 8147:1995 Shipbuilding and marine structures – Derrick rigs and component parts – Vocabulary ISO 8152:1984 Earth-moving machinery – Operation and maintenance – Training of mechanics ISO 8153 Aerospace fluid systems and components – Vocabulary ISO 8153-1:2009 Part 1: Hose assemblies ISO 8157:2015 Fertilizers and soil conditioners – Vocabulary ISO 8159:1987 Textiles – Morphology of fibres and yarns – Vocabulary ISO 8160:1987 Textiles – Textured filament yarns – Vocabulary ISO 8178 Reciprocating internal combustion engines - Exhaust emission measurement ISO 8180 Ductile iron pipelines – Polyethylene sleeving for site application ISO 8199:2005 Water quality – General guidance on the enumeration of micro-organisms by culture ISO/IEC 8208:2000 Information technology – Data communications – X.25 Packet Layer Protocol for Data Terminal Equipment ISO/IEC 8211:1994 Information technology - Specification for a data descriptive file for information interchange ISO 8217:2017 Petroleum products - Fuels (class F) - Specifications of marine fuels ISO 8229:1991 Operations and baths relating to dry-cleaning machines – Vocabulary ISO 8277:2013 Ships and marine technology – Pipework and machinery – Information transfer ISO 8297:1994 Acoustics – Determination of sound power levels of multisource industrial plants for evaluation of sound pressure levels in the environment – Engineering method ISO 8316:1987 Measurement of liquid flow in closed conduits – Method by collection of the liquid in a volumetric tank ISO 8317:2015 Child-resistant packaging - Requirements and testing procedures for reclosable packages ISO 8319 Orthopaedic instruments – Drive connections ISO 8319-1:1996 Part 1: Keys for use with screws with hexagon socket heads ISO 8319-2:1986 Part 2: Screwdrivers for single slot head screws, screws with cruciate slot and cross-recessed head screws ISO/IEC 8326:1996 Information technology – Open Systems Interconnection – Session service definition ISO/IEC 8327 Information technology – Open Systems Interconnection – Connection-oriented Session protocol ISO/IEC 8327-1:1996 Protocol specification ISO/IEC 8327-2:1996 Protocol Implementation Conformance Statement (PICS) proforma ISO 8330:2014 Rubber and plastics hoses and hose assemblies - Vocabulary ISO 8333:1985 Liquid flow measurement in open channels by weirs and flumes – V-shaped broad-crested weirs ISO 8343:1985 Ferronickel - Determination of silicon content - Gravimetric method ISO/IEC 8348:2002 Information technology – Open Systems Interconnection – Network service definition ISO 8362 Injection containers and accessories ISO 8362-1:2009 Part 1: Injection vials made of glass tubing ISO 8362-2:2015 Part 2: Closures for injection vials ISO 8362-3:2001 Part 3: Aluminium caps for injection vials ISO 8362-4:2011 Part 4: Injection vials made of moulded glass ISO 8362-5:2016 Part 5: Freeze drying closures for injection vials ISO 8362-6:2010 Part 6: Caps made of aluminium-plastics combinations for injection vials ISO 8362-7:2006 Part 7: Injection caps made of aluminium-plastics combinations without overlapping plastics part ISO/TR 8363:1997 Measurement of liquid flow in open channels — General guidelines for selection of method [Withdrawn: replaced by ISO 18365] ISO 8368:1999 Hydrometric determinations – Flow measurements in open channels using structures – Guidelines for selection of structure ISO 8373:2012 Manipulating industrial robots – Vocabulary ISO 8378 Information processing – Data interchange on 130 mm (5.25 in) flexible disk cartridges using modified frequency modulation recording at 7 958 ftprad, 3,8 tpmm (96 tpi), on both sides ISO 8378-1:1986 Part 1: Dimensional, physical and magnetic characteristics ISO 8378-2:1986 Part 2: Track format A ISO 8378-3:1986 Part 3: Track format B ISO 8384:2000 Ships and marine technology – Dredgers – Vocabulary ISO 8388:1998 Knitted fabrics – Types – Vocabulary ISO 8421 Fire protection - Vocabulary ISO 8421-1:1987 Part 1: General terms and phenomena of fire ISO 8421-2:1987 Part 2: Structural fire protection ISO 8421-6:1987 Part 6: Evacuation and means of escape ISO 8421-7:1987 Part 7: Explosion detection and suppression means ISO 8422:2006 Sequential sampling plans for inspection by attributes ISO 8423:2008 Sequential sampling plans for inspection by variables for percent nonconforming (known standard deviation) ISO 8429:1986 Optics and optical instruments – Ophthalmology – Graduated dial scale ISO 8439:1990 Forms design - Basic layout ISO 8440:1986 Location of codes in trade documents ISO/IEC 8441 Information technology – High density digital recording (HDDR) ISO/IEC 8441-1:1991 Part 1: Unrecorded magnetic tape for (HDDR) applications ISO/IEC 8441-2:1991 Part 2: Guide for interchange practice ISO 8459:2009 Information and documentation - Bibliographic data element directory for use in data exchange and enquiry ISO 8462 Information processing – Data interchange on 6,30 mm (0.25 in) magnetic tape cartridge using GCR recording at 394 ftpmm (10 000 ftpi), 39 cpmm (1 000 cpi) ISO 8462-1:1986 Part 1: Mechanical, physical and magnetic properties ISO 8462-2:1986 Part 2: Streaming mode ISO/IEC 8473 Information technology – Protocol for providing the connectionless-mode network service ISO/IEC 8473-1:1998 Protocol specification ISO/IEC 8473-2:1996 Part 2: Provision of the underlying service by an ISO/IEC 8802 subnetwork ISO/IEC 8473-3:1995 Provision of the underlying service by an X.25 subnetwork ISO/IEC 8473-4:1995 Provision of the underlying service by a subnetwork that provides the OSI data link service ISO/IEC 8473-5:1997 Provision of the underlying service by ISDN circuit-switched B-channels ISO/IEC 8480:1995 Information technology – Telecommunications and information exchange between systems – DTE/DCE interface back-up control operation using ITU-T Recommendation V.24 interchange circuits ISO/IEC 8481:1996 Information technology – Telecommunications and information exchange between systems – DTE to DTE direct connections ISO/IEC 8482:1993 Information technology – Telecommunications and information exchange between systems – Twisted pair multipoint interconnections ISO/IEC 8484:2014 Information technology – Magnetic stripes on savingsbooks ISO 8485:1989 Programming languages - APL ISO 8498:1990 Woven fabrics – Description of defects – Vocabulary ISO 8499:2003 Knitted fabrics – Description of defects – Vocabulary ISO 8501 Preparation of steel substrates before application of paints and related products – Visual assessment of surface cleanliness ISO 8501-1:2007 Part 1: Rust grades and preparation grades of uncoated steel substrates and of steel substrates after overall removal of previous coatings ISO 8501-2:1994 Part 2: Preparation grades of previously coated steel substrates after localized removal of previous coatings ISO 8501-3:2006 Part 3: Preparation grades of welds, edges and other areas with surface imperfections ISO 8501-4:2006 Part 4: Initial surface conditions, preparation grades and flash rust grades in connection with high-pressure water jetting ISO 8502 Preparation of steel substrates before application of paints and related products - Tests for the assessment of surface cleanliness ISO 8502-2:2017 Part 2: Laboratory determination of chloride on cleaned surfaces ISO 8502-3:2017 Part 3: Assessment of dust on steel surfaces prepared for painting (pressure-sensitive tape method) ISO 8502-4:2017 Part 4: Guidance on the estimation of the probability of condensation prior to paint application ISO 8502-5:1998 Part 5: Measurement of chloride on steel surfaces prepared for painting (ion detection tube method ISO 8502-6:2006 Part 6: Extraction of soluble contaminants for analysis - The Bresle method ISO 8502-9:1998 Part 9: Field method for the conductometric determination of water-soluble salts ISO 8502-11:2006 Part 11: Field method for the turbidimetric determination of water-soluble sulfate ISO 8503 Preparation of steel substrates before application of paints and related products - Surface roughness characteristics of blast-cleaned steel substrates ISO 8503-1:2012 Part 1: Specifications and definitions for ISO surface profile comparators for the assessment of abrasive blast-cleaned surfaces ISO 8503-2:2012 Part 2: Method for the grading of surface profile of abrasive blast-cleaned steel - Comparator procedure ISO 8503-3:2012 Part 3: Method for the calibration of ISO surface profile comparators and for the determination of surface profile - Focusing microscope procedure ISO 8503-4:2012 Part 4: Method for the calibration of ISO surface profile comparators and for the determination of surface profile - Stylus instrument procedure ISO 8503-5:2017 Part 5: Replica tape method for the determination of the surface profile ISO 8504 Preparation of steel substrates before application of paints and related products - Surface preparation methods ISO 8504-1:2000 Part 1: General principles ISO 8504-2:2000 Part 2: Abrasive blast-cleaning ISO 8504-3:1993 Part 3: Hand- and power-tool cleaning ISO 8506:2024 Information technology — Automatic identification and data capture technology — AIDC application in industrial construction ISO 8512 Surface plates ISO 8512-1:1990 Part 1: Cast iron ISO 8512-2:1990 Part 2: Granite ISO/TR 8517:1988 Rubber- or plastics-covered rollers – Glossary ISO 8525:2008 Airborne noise emitted by machine tools – Operating conditions for metal-cutting machines ISO 8528 Reciprocating internal combustion engine driven alternating current generating sets ISO 8528-1:2005 Part 1: Application, ratings and performance ISO 8528-2:2005 Part 2: Engines ISO 8528-3:2005 Part 3: Alternating current generators for generating sets ISO 8528-4:2005 Part 4: Controlgear and switchgear ISO 8528-5:2013 Part 5: Generating sets ISO 8528-6:2005 Part 6: Test methods ISO 8528-7:2017 Part 7: Technical declarations for specification and design ISO 8528-8:2016 Part 8: Requirements and tests for low-power generating sets ISO 8528-9:2017 Part 9: Measurement and evaluation of mechanical vibrations ISO 8528-10:1998 Part 10: Measurement of airborne noise by the enveloping surface method ISO 8528-12:1997 Part 12: Emergency power supply to safety services ISO 8528-13:2016 Part 13: Safety ISO 8529 Reference neutron radiations ISO 8529-1:2001 Part 1: Characteristics and methods of production ISO 8529-2:2000 Part 2: Calibration fundamentals of radiation protection devices related to the basic quantities characterizing the radiation field ISO 8529-3:1998 Part 3: Calibration of area and personal dosimeters and determination of response as a function of energy and angle of incidence ISO 8532:1995 Securities – Format for transmission of certificate numbers ISO 8536 Infusion equipment for medical use ISO 8536-1:2011 Part 1: Infusion glass bottles ISO 8536-2:2010 Part 2: Closures for infusion bottles ISO 8536-3:2009 Part 3: Aluminium caps for infusion bottles ISO 8536-4:2010 Part 4: Infusion sets for single use, gravity feed ISO 8536-5:2004 Part 5: Burette infusion sets for single use, gravity feed ISO 8536-6:2016 Part 6: Freeze drying closures for infusion bottles ISO 8536-7:2009 Part 7: Caps made of aluminium-plastics combinations for infusion bottles ISO 8536-8:2015 Part 8: Infusion sets for single use with pressure infusion apparatus ISO 8536-9:2015 Part 9: Fluid lines for single use with pressure infusion equipment ISO 8536-10:2015 Part 10: Accessories for fluid lines for single use with pressure infusion equipment ISO 8536-11:2015 Part 11: Infusion filters for single use with pressure infusion equipment ISO 8536-12:2007 Part 12: Check valves ISO 8536-13:2016 Part 13: Graduated flow regulators for single use with fluid contact ISO 8536-14:2016 Part 14: Clamps and flow regulators for transfusion and infusion equipment without fluid contact ISO 8537:2016 Sterile single-use syringes, with or without needle, for insulin ISO 8540:1993 Open front mechanical power presses - Vocabulary ISO 8548 Prosthetics and orthotics – Limb deficiencies ISO 8548-1:1989 Part 1: Method of describing limb deficiencies present at birth ISO 8548-2:1993 Part 2: Method of describing lower limb amputation stumps ISO 8548-3:1993 Part 3: Method of describing upper limb amputation stumps ISO 8548-4:1998 Part 4: Description of causal conditions leading to amputation ISO 8548-5:2003 Part 5: Description of the clinical condition of the person who has had an amputation ISO 8549 Prosthetics and orthotics - Vocabulary ISO 8549-1:1989 Part 1: General terms for external limb prostheses and external orthoses ISO 8549-2:1989 Part 2: Terms relating to external limb prostheses and wearers of these prostheses ISO 8549-3:1989 Part 3: Terms relating to external orthoses ISO 8549-4:2014 Part 4: Terms relating to limb amputation ISO/TR 8550 Guidance on the selection and usage of acceptance sampling systems for inspection of discrete items in lots ISO/TR 8550-1:2007 Part 1: Acceptance sampling ISO/TR 8550-2:2007 Part 2: Sampling by attributes ISO/TR 8550-3:2007 Part 3: Sampling by variables ISO 8551:2003 Prosthetics and orthotics – Functional deficiencies – Description of the person to be treated with an orthosis, clinical objectives of treatment, and functional requirements of the orthosis ISO 8552:2004 Milk – Estimation of psychrotrophic microorganisms – Colony-count technique at 21 degrees C (Rapid method) ISO 8553:2004 Milk – Enumeration of microorganisms – Plate-loop technique at 30 degrees C ISO 8559:1989 Garment construction and anthropometric surveys – Body dimensions [Withdrawn: replaced by ISO 8559-1:2017] ISO 8559 Size designation of clothes ISO 8559-1:2017 Part 1: Anthropometric definitions for body measurement ISO 8559-2:2017 Part 2: Primary and secondary dimension indicators ISO 8560:1986 Technical drawings – Construction drawings – Representation of modular sizes, lines and grids ISO 8568:2007 Mechanical shock – Testing machines – Characteristics and performance ISO 8571 Information processing systems - Open Systems Interconnection - File Transfer, Access and Management ISO 8571-1:1988 Part 1: General introduction ISO 8571-2:1988 Part 2: Virtual Filestore Definition ISO 8571-3:1988 Part 3: File Service Definition ISO 8571-4:1988 Part 4: File Protocol Specification ISO/IEC 8571-5:1990 Part 5: Protocol Implementation Conformance Statement Proforma ISO 8573 Compressed air ISO 8573-1:2010 Contaminants and purity classes ISO 8573-2:2007 Test methods for oil aerosol content ISO 8573-3:1999 Test methods for measurement of humidity ISO 8573-4:2001 Test methods for solid particle content ISO 8573-5:2001 Test methods for oil vapour and organic solvent content ISO 8573-6:2003 Test methods for gaseous contaminant content ISO 8573-7:2003 Test method for viable microbiological contaminant content ISO 8573-8:2004 Test methods for solid particle content by mass concentration ISO 8573-9:2004 Test methods for liquid water content ISO 8579 Acceptance code for gear units ISO 8579-1:2002 Part 1: Test code for airborne sound ISO 8583 Financial transaction card originated messages – Interchange message specifications ISO 8586:2012 Sensory analysis – General guidelines for the selection, training and monitoring of selected assessors and expert sensory assessors ISO 8596:2009 Ophthalmic optics – Visual acuity testing – Standard optotype and its presentation ISO 8598 Optics and optical instruments – Focimeters ISO 8598-1:2014 Part 1: General purpose instruments ISO 8600 Endoscopes – Medical endoscopes and endotherapy devices ISO 8600-1:2015 Part 1: General requirements ISO 8600-2:2015 Part 2: Particular requirements for rigid bronchoscopes ISO 8600-3:1997 Part 3: Determination of field of view and direction of view of endoscopes with optics ISO 8600-4:2014 Part 4: Determination of maximum width of insertion portion ISO 8600-5:2005 Part 5: Determination of optical resolution of rigid endoscopes with optics ISO 8600-6:2005 Part 6: Vocabulary ISO 8600-7:2012 Part 7: Basic requirements for medical endoscopes of water-resistant type ISO 8601:2019 Data elements and interchange formats – Information interchange – Representation of dates and times ISO/IEC 8602:1995 Information technology – Protocol for providing the OSI connectionless-mode transport service ISO 8604:1988 Plastics – Prepregs – Definitions of terms and symbols for designations ISO 8608:2016 Mechanical vibration – Road surface profiles – Reporting of measured data ISO 8612:2009 Ophthalmic instruments – Tonometers ISO/IEC 8613 Information technology – Open Document Architecture (ODA) and interchange format ISO 8614:1997 Ski bindings – Vocabulary ISO 8615:1991 Implants for surgery – Fixation devices for use in the ends of the femur in adults ISO 8624:2011 Ophthalmic optics – Spectacle frames – Measuring system and terminology ISO 8625 Aerospace – Fluid systems – Vocabulary ISO 8625-1:1993 Part 1: General terms and definitions related to pressure ISO 8625-2:1991 Part 2: General terms and definitions relating to flow ISO 8625-3:1991 Part 3: General terms and definitions relating to temperature ISO 8625-4:2011 Part 4: General terms and definitions relating to control/actuation systems ISO 8626:1989 Servo-hydraulic test equipment for generating vibration – Method of describing characteristics ISO 8630 Information processing – Data interchange on 130 mm (5.25 in) flexible disk cartridges using modified frequency modulation recording at 13 262 ftprad, on 80 tracks on each side ISO 8630-1:1987 Part 1: Dimensional, physical and magnetic characteristics ISO 8630-2:1987 Part 2: Track format A for 77 tracks ISO 8630-3:1987 Part 3: Track format B for 80 tracks ISO/IEC 8631:1989 Information technology - Program constructs and conventions for their representation ISO/IEC 8632 Information technology – Computer graphics – Metafile for the storage and transfer of picture description information ISO/IEC 8632-1:1999 Part 1: Functional specification ISO/IEC 8632-2:1992 Part 2: Character encoding [withdrawn 2001-06-21] ISO/IEC 8632-3:1999 Part 3: Binary encoding ISO/IEC 8632-4:1999 Part 4: Clear text encoding ISO 8637:2010 Cardiovascular implants and extracorporeal systems – Haemodialysers, haemodiafilters, haemofilters and haemoconcentrators ISO 8638:2010 Cardiovascular implants and extracorporeal systems – Extracorporeal blood circuit for haemodialysers, haemodiafilters and haemofilters ISO 8640 Textile machinery and accessories – Flat warp knitting machines ISO 8640-1:2004 Part 1: Vocabulary of basic structure and knitting elements ISO 8640-2:2004 Part 2: Vocabulary of warp let-off, fabric take-up and batching ISO 8640-3:2002 Part 3: Vocabulary of patterning devices ISO 8640-4:1996 Part 4: Stitch bonding machines and stitch bonding devices ISO 8648:1988 Information processing systems – Open Systems Interconnection – Internal organization of the Network Layer ISO/IEC 8650 Information technology – Open Systems Interconnection – Protocol specification for the Association Control Service Element ISO/IEC 8650-2:1997 Protocol Implementation Conformance Statement (PICS) proforma ISO 8651 Information technology – Computer graphics – Graphical Kernel System (GKS) language bindings ISO 8651-1:1988 Part 1: FORTRAN ISO 8651-2:1988 Part 2: Pascal ISO 8651-3:1988 Part 3: Ada ISO/IEC 8651-4:1995 Part 4: C ISO/IEC 8652:2012 Information technology – Programming languages – Ada ISO 8653:1986 Jewellery – Ring-sizes – Definition, measurement and designation ISO 8655 Piston-operated volumetric apparatus ISO 8655-1:2002 Part 1: Terminology, general requirements and user recommendations ISO 8655-2:2002 Part 2: Piston pipettes ISO 8655-3:2002 Part 3: Piston burettes ISO 8655-4:2002 Part 4: Dilutors ISO 8655-5:2002 Part 5: Dispensers ISO 8655-6:2002 Part 6: Gravimetric methods for the determination of measurement error ISO 8655-7:2005 Part 7: Non-gravimetric methods for the assessment of equipment performance ISO 8669 Urine collection bags ISO 8669-1:1988 Part 1: Vocabulary ISO 8670 Ostomy collection bags ISO 8670-1:1988 Part 1: Vocabulary ISO 8691 Petroleum products – Low levels of vanadium in liquid fuels – Determination by flameless atomic absorption spectrometry after ashing ISO 8695:2010 Tools for pressing - Punches - Nomenclature and terminology ISO/TR 8713:2012 Electrically propelled road vehicles – Vocabulary ISO 8769:2016 Reference sources - Calibration of surface contamination monitors - Alpha-, beta- and photon emitters ISO 8777:1993 Information and documentation - Commands for interactive text searching ISO 8784 Pulp, paper and board – Microbiological examination ISO 8784-1:2014 Part 1: Enumeration of bacteria and bacterial spores based on disintegration ISO 8785:1998 Geometrical Product Specification (GPS) - Surface imperfections - Terms, definitions and parameters ISO 8790:1987 Information processing systems - Computer system configuration diagram symbols and conventions ISO/IEC 8802 Information technology – Telecommunications and information exchange between systems – Local and metropolitan area networks – Specific requirements ISO/IEC/IEEE 8802-A:2015 Part A: Overview and architecture ISO/IEC TR 8802-1:2001 Part 1: Overview of Local Area Network Standards ISO/IEC/IEEE 8802-1Q:2016 Part 1Q: Bridges and bridged networks ISO/IEC/IEEE 8802-1X:2013 Part 1X: Port-based network access control ISO/IEC/IEEE 8802-1AB:2017 Part 1AB: Station and media access control connectivity discovery ISO/IEC/IEEE 8802-1AE:2013 Part 1AE: Media access control (MAC) security ISO/IEC/IEEE 8802-1AR:2014 Part 1AR: Secure device identity ISO/IEC/IEEE 8802-1AS:2014 Part 1AS: Timing and synchronization for time-sensitive applications in bridged local area networks ISO/IEC/IEEE 8802-1AX:2016 Part 1AX: Link aggregation ISO/IEC/IEEE 8802-1BA:2016 Part 1BA: Audio video bridging (AVB) systems ISO/IEC/IEEE 8802-1BR:2016 Part 1BR: Virtual bridged local area networks – Bridge port extension ISO/IEC 8802-2:1998 Part 2: Logical link control ISO/IEC/IEEE 8802-3:2017 Part 3: Standard for Ethernet ISO/IEC/IEEE 8802-3-1:2015 Part 3-1: Standard for management information base (MIB) – Definitions for Ethernet ISO/IEC 8802-5:1998 Part 5: Token Ring access method and physical layer specifications ISO/IEC/IEEE 8802-11:2012 Part 11: Wireless LAN medium access control (MAC) and physical layer (PHY) specifications ISO/IEC/IEEE 8802-15-4:2010 Part 15-4: Wireless medium access control (MAC) and physical layer (PHY) specifications for low-rate wireless personal area networks (WPANs) ISO/IEC/IEEE 8802-22:2015 Part 22: Cognitive Wireless RAN Medium Access Control (MAC) and Physical Layer (PHY) Specifications: Policies and Procedures for Operation in the TV Bands ISO 8805 Information processing systems – Computer graphics – Graphical Kernel System for Three Dimensions (GKS-3D) functional description ISO/IEC 8806 Information technology – Computer graphics – Graphical Kernel System for Three Dimensions (GKS-3D) language bindings ISO/IEC 8806-4 Part 4: C ISO 8807:1989 Information processing systems – Open Systems Interconnection – LOTOS – A formal description technique based on the temporal ordering of observational behaviour ISO 8811:2000 Earth-moving machinery – Rollers and compactors – Terminology and commercial specifications ISO 8812:2016 Earth-moving machinery – Backhoe loaders – Terminology and commercial specifications ISO 8815:1994 Aircraft – Electrical cables and cable harnesses – Vocabulary ISO/IEC 8822:1994 Information technology – Open Systems Interconnection – Presentation service definition ISO/IEC 8823 Information technology – Open Systems Interconnection – Connection-oriented presentation protocol ISO/IEC 8823-1:1994 Protocol specification ISO/IEC 8823-2:1997 Protocol Implementation Conformance Statement (PICS) proforma ISO/IEC 8824 Information technology – Abstract Syntax Notation One (ASN.1) ISO/IEC 8824-1:2015 Specification of basic notation ISO/IEC 8824-2:2015 Information object specification ISO/IEC 8824-3:2015 Constraint specification ISO/IEC 8824-4:2015 Parameterization of ASN.1 specifications ISO/IEC 8825 Information technology – ASN.1 encoding rules ISO/IEC 8825-1:2015 Specification of Basic Encoding Rules (BER), Canonical Encoding Rules (CER) and Distinguished Encoding Rules (DER) ISO/IEC 8825-2:2015 Specification of Packed Encoding Rules (PER) ISO/IEC 8825-3:2015 Specification of Encoding Control Notation (ECN) ISO/IEC 8825-4:2015 XML Encoding Rules (XER) ISO/IEC 8825-5:2015 Mapping W3C XML schema definitions into ASN.1 ISO/IEC 8825-6:2015 Registration and application of PER encoding instructions ISO/IEC 8825-7:2015 Part 7: Specification of Octet Encoding Rules (OER) ISO 8826 Technical drawings – Rolling bearings ISO 8826-1:1989 Part 1: General simplified representation ISO 8826-2:1994 Part 2: Detailed simplified representation ISO 8827:1988 Implants for surgery – Staples with parallel legs for orthopaedic use – General requirements ISO 8828:2014 Implants for surgery – Guidance on care and handling of orthopaedic implants ISO 8835 Inhalational anaesthesia systems ISO 8835-7:2011 Part 7: Anaesthetic systems for use in areas with limited logistical supplies of electricity and anaesthetic gases ISO 8836:2014 Suction catheters for use in the respiratory tract ISO 8843:2005 Aircraft – Crimp-removable contacts for electrical connectors – Identification system ISO 8855:2011 Road vehicles – Vehicle dynamics and road-holding ability – Vocabulary ISO/IEC 8859 Information technology – 8-bit single-byte coded graphic character sets ISO/IEC 8859-1:1998 Part 1: Latin alphabet No. 1 ISO/IEC 8859-2:1999 Part 2: Latin alphabet No. 2 ISO/IEC 8859-3:1999 Part 3: Latin alphabet No. 3 ISO/IEC 8859-4:1998 Part 4: Latin alphabet No. 4 ISO/IEC 8859-5:1999 Part 5: Latin/Cyrillic alphabet ISO/IEC 8859-6:1999 Part 6: Latin/Arabic alphabet ISO/IEC 8859-7:2003 Part 7: Latin/Greek alphabet ISO/IEC 8859-8:1999 Part 8: Latin/Hebrew alphabet ISO/IEC 8859-9:1999 Part 9: Latin alphabet No. 5 ISO/IEC 8859-10:1998 Part 10: Latin alphabet No. 6 ISO/IEC 8859-11:2001 Part 11: Latin/Thai alphabet ISO/IEC 8859-13:1998 Part 13: Latin alphabet No. 7 ISO/IEC 8859-14:1998 Part 14: Latin alphabet No. 8 (Celtic) ISO/IEC 8859-15:1999 Part 15: Latin alphabet No. 9 ISO/IEC 8859-16:2001 Part 16: Latin alphabet No. 10 ISO 8860 Information processing – Data interchange on 90 mm (3.5 in) flexible disk cartridges using modified frequency modulation recording at 7 958 ftprad on 80 tracks on each side ISO 8860-1:1987 Part 1: Dimensional, physical and magnetic characteristics ISO 8860-2:1987 Part 2: Track format ISO 8871 Elastomeric parts for parenterals and for devices for pharmaceutical use ISO 8871-1:2003 Part 1: Extractables in aqueous autoclavates ISO 8871-2:2003 Part 2: Identification and characterization ISO 8871-3:2003 Part 3: Determination of released-particle count ISO 8871-4:2006 Part 4: Biological requirements and test methods ISO 8871-5:2016 Part 5: Functional requirements and testing ISO 8872:2003 Aluminium caps for transfusion, infusion and injection bottles – General requirements and test methods ISO/IEC 8877:1992 Information technology – Telecommunications and information exchange between systems – Interface connector and contact assignments for ISDN Basic Access Interface located at reference points S and T ISO/IEC 8878:1992 Information technology – Telecommunications and information exchange between systems – Use of X.25 to provide the OSI Connection-mode Network Service ISO 8879:1986 Information processing – Text and office systems – Standard Generalized Markup Language (SGML) ISO/IEC 8880 Information technology — Telecommunications and information exchange between systems — Protocol combinations to provide and support the OSI Network Service ISO/IEC 8880-1:1990 Part 1: General principles [Withdrawn: replaced by ISO/IEC TR 13532:1995, now withdrawn without replacement] ISO/IEC 8880-2:1992 Part 2: Provision and support of the connection-mode Network Service [Withdrawn: replaced by ISO/IEC TR 13532:1995, now withdrawn without replacement] ISO/IEC 8880-3:1990 Part 3: Provision and support of the connectionless-mode Network Service [Withdrawn: replaced by ISO/IEC TR 13532:1995, now withdrawn without replacement] ISO/IEC 8881:1989 Information processing systems – Data communications – Use of the X.25 packet level protocol in local area networks ISO/IEC 8882 Information technology – Telecommunications and information exchange between systems – X.25 DTE conformance testing ISO/IEC 8882-1:1996 Part 1: General principles ISO/IEC 8882-2:2000 Part 2: Data link layer conformance test suite ISO/IEC 8882-3:2000 Part 3: Packet layer conformance test suite ISO 8884:1989 Information processing — Text and office systems — Keyboards for multiple Latin-alphabet languages — Layout and operation [Withdrawn: replaced with ISO 9995-(1,7)] ISO 8885:1987 Information processing systems — Data communication — High-level data link control procedures — General purpose XID frame information field content and format [Withdrawn without replacement] ISO/IEC 8886:1996 Information technology – Open Systems Interconnection – Data link service definition ISO 8887 Technical product documentation – Design for manufacturing, assembling, disassembling and end-of-life processing ISO 8887-1:2017 Part 1: General concepts and requirements ISO 8891:1998 Dental casting alloys with noble metal content of at least 25 % but less than 75 % [Withdrawn: replaced with ISO 22674] ISO 8909 Forage harvesters ISO 8909-1:1994 Part 1: Vocabulary ISO 8910:1993 Machinery and equipment for working the soil – Mouldboard plough working elements – Vocabulary ISO 8927:1991 Earth-moving machinery – Machine availability – Vocabulary ISO 8930:1987 General principles on reliability for structures – List of equivalent terms ISO 8936:2017 Awnings for leisure accommodation vehicles - Requirements and test methods ISO 8954 Ferroalloys - Vocabulary ISO 8954-1:1990 Part 1: Materials ISO 8954-2:1990 Part 2: Sampling and sample preparation ISO 8954-3:1990 Part 3: Sieve analysis ISO 8957:1996 Information and documentation - Hebrew alphabet coded character sets for bibliographic information interchange ISO 8965:2013 Logging industry – Technology – Terms and definitions ISO 8979:2004 Pliers and nippers for electronics - Nomenclature ISO 8980 Ophthalmic optics – Uncut finished spectacle lenses ISO 8980-1:2017 Part 1: Specifications for single-vision and multifocal lenses ISO 8980-2:2017 Part 2: Specifications for power-variation lenses ISO 8980-3:2013 Part 3: Transmittance specifications and test methods ISO 8980-4:2006 Part 4: Specifications and test methods for anti-reflective coatings ISO 8980-5:2005 Part 5: Minimum requirements for spectacle lens surfaces claimed to be abrasion-resistant ISO 8999:2001 Reciprocating internal combustion engines - Graphical symbols
=== Polymerization and hydration === Monomeric CH2O is a gas and is rarely encountered in the laboratory. Aqueous formaldehyde, unlike some other small aldehydes (which need specific conditions to oligomerize through aldol condensation) oligomerizes spontaneously at a common state. The trimer 1,3,5-trioxane, (CH2O)3, is a typical oligomer. Many cyclic oligomers of other sizes have been isolated. Similarly, formaldehyde hydrates to give the geminal diol methanediol, which condenses further to form hydroxy-terminated oligomers HO(CH2O)nH. The polymer is called paraformaldehyde. The higher concentration of formaldehyde—the more equilibrium shifts towards polymerization. Diluting with water or increasing the solution temperature, as well as adding alcohols (such as methanol or ethanol) lowers that tendency. Gaseous formaldehyde polymerizes at active sites on vessel walls, but the mechanism of the reaction is unknown. Small amounts of hydrogen chloride, boron trifluoride, or stannic chloride present in gaseous formaldehyde provide the catalytic effect and make the polymerization rapid.
==== Lignans ==== Plant lignans are associated with high fiber foods such as cereal brans and beans are the principal precursor to mammalian lignans which have an ability to bind to human estrogen sites. Soybeans are a significant source of mammalian lignan precursor secoisolariciresinol containing 13–273 μg/100 g dry weight.
Sources: en.wikipedia.org
== Processing == Cocoa pods are harvested by cutting them from the tree using a machete, or by knocking them off the tree using a stick. Pods are harvested when they are ripe, as beans in unripe pods have a low cocoa butter content, or low sugar content, impacting the ultimate flavor.
In the first few days after the call for overseas service on 9 August, the result in many TF units was hesitant, with some units only recording around 50% volunteering, partly because men with families were reluctant to leave well-paid jobs especially while there was talk of a German invasion of the homeland, but the pace rapidly accelerated and, within a fortnight, 70 infantry battalions and many other units had collectively volunteered for France. initially TF units were either fed into regular brigades or used for secondary tasks, such as guarding lines of communication but, by the end of April 1915, six full Territorial divisions had been deployed into the fight. The (Regular) Expeditionary Force of six divisions had been rapidly sent to the Continent, where, facing overwhelming odds, they secured the left flank of the French Army. Of the 90,000 members of the original BEF deployed in August, four-fifths were dead or wounded by Christmas. So the arrival of the Territorials, first as reinforcements and then in whole divisions came at a critical juncture, while the New Army was still forming and training. Many of the Territorial units suffered immediate heavy casualties and on the night of 20 April 1915 Second Lieutenant Geoffrey Woolley of the Queen Victoria Rifles, secured the first of the 71 Victoria Crosses won by Territorials in the First World War.
Genera surviving today comprise 56% of the genera in Baltic amber fossils (early Oligocene), and 92% of the genera in Dominican amber fossils (apparently early Miocene). Termites live in colonies and are sometimes called "white ants", but termites are only distantly related to ants. They are the sub-order Isoptera, and together with cockroaches, they form the order Blattodea. Blattodeans are related to mantids, crickets, and other winged insects that do not undergo complete metamorphosis. Like ants, termites are eusocial, with sterile workers, but they differ greatly in the genetics of reproduction. The similarity of their social structure to that of ants is attributed to convergent evolution. Velvet ants look like large ants, but are wingless female wasps.
==== AP1 ==== Activation of AP1 factor involves three MAPK signaling pathways. These pathways use a phosphorylation cascade of three successive acting protein kinases to transmit a signal. The three MAPK pathways in T cells involve kinases of different specificities belonging to each of the MAP3K, MAP2K, MAPK families. Initial activation is done by the GTPase Ras or Rac which phosphorylate the MAP3K. A cascade involving the enzymes Raf, MEK1, ERK results in the phosphorylation of Jun, conformational change allows Jun to bind to Fos and hence AP-1 to form. AP-1 then acts as transcription factor. Raf is activated via the second messenger DAG, SOS, and Ras. DAG recruits among other proteins the RAS guanyl nucleotide-releasing protein (RasGRP), a guanine nucleotide exchange factor (GEF), to the membrane. RasGRP activates the small GTPase Ras by exchanging guanosine diphosphate (GDP) bound to Ras against guanosine triphosphate (GTP). Ras can also be activated by the guanine nucleotide exchange factor SOS which binds to the LAT signalosome. Ras then initiates the MAPK cascade. The second MAPK cascade with MEKK1, JNKK, JNK induces protein expression of Jun. Another cascade, also involving MEKK1 as MAPK3, but then activating MKK3 /6 and p38 induces Fos transcription. Activation of MEKK1, additionally to being activated by Ras, involves Slp-76 recruiting the GEF Vav to the LAT signalosome, which then activates the GTPase Rac. Rac and Ras activate MEKK1 and thereby initiate the MAPK cascade.
=== Inflammatory arthropathies === Rheumatoid arthritis Spondyloarthropathies Ankylosing spondylitis Reactive arthritis (reactive arthropathy) Psoriatic arthropathy Enteropathic arthropathy Juvenile idiopathic arthritis (JIA) Crystal arthropathies: gout, pseudogout Septic arthritis Raynaud's Disease
Sources: en.wikipedia.org
Reports describe effects on GABA-A receptor expression, monoamine turnover, and neurotrophic factor levels. These are proposed mechanisms drawn mainly from animal models. No single molecular target has been established.
Intranasal delivery is the route described in most published work. It is used because the peptide is degraded quickly once it reaches circulation. Direct evidence of brain penetration in humans is lacking.
Most trials are small, regionally concentrated, and often lack rigorous blinding or placebo control. Independent replication is limited. Reviews in English generally rate the evidence as preliminary.
Selank is a synthetic peptide made of seven amino acids. It is modeled on tuftsin, a natural tetrapeptide, with an added three-residue tail. It is not a small-molecule drug.