If you have been reading about prohibited list 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 2025-09-21. Where a claim depends on a specific study, the study is described rather than over-claimed.
Identity and purity are usually assessed by reversed-phase high-performance liquid chromatography together with mass spectrometry. The chromatogram provides a purity estimate as a percentage of total peak area, while the mass spectrum confirms that the observed mass matches the expected value. Amino acid analysis or tandem mass spectrometry sequencing can provide additional confirmation. Reported purity figures depend on the column, gradient, and detection wavelength, so values from different laboratories are not directly comparable without method details.
Lyophilised peptide is normally reconstituted with sterile water or a neutral buffer shortly before use. Because repeated freeze-thaw cycles can degrade the material, dividing a reconstituted solution into single-use aliquots is a common practice. Working solutions are usually kept cold and protected from light. The exact shelf life depends on concentration, buffer composition, and handling, so it is often determined empirically rather than assumed.
Peptide bonds are susceptible to hydrolysis under extreme pH and to enzymatic cleavage if proteases are present. Heat, oxidising agents, and prolonged exposure to light also contribute to loss of material. Aggregation can occur at high concentrations or in certain buffer systems, and it may not be visible to the eye. Storage at -20 C or below is typical for both powder and aliquoted solutions, and desiccation of the powder is preferred.
The seven-residue chain carries several polar and charged side chains, so it dissolves readily in water and in aqueous buffers near neutral pH. No cysteine is present, so disulphide formation is not a concern and reducing agents are unnecessary. Dilute ammonium hydroxide or acetonitrile-water mixtures are sometimes used for stock solutions when initial dissolution is slow. Strongly alkaline conditions and prolonged contact with oxidising agents are avoided because they can modify lysine-containing stretches, and haze in solution usually signals incomplete dissolution or aggregated material.
Identity and purity are checked with reversed-phase high-performance liquid chromatography, which separates the target sequence from truncated or deletion analogues, and with mass spectrometry, which confirms the expected molecular mass. Amino acid analysis and peptide mapping give orthogonal confirmation but are used less often outside specialist laboratories. Counter-ion content varies: material purified on trifluoroacetic acid gradients retains trifluoroacetate, and ion exchange can convert the salt form. Residual water and solvent are measured by Karl Fischer titration or thermogravimetric analysis, and any purity figure should be read together with the method used to obtain it.
Lyophilised peptide powders are hygroscopic, and the fragment absorbs atmospheric moisture when a vial is opened at room temperature. Weighing and aliquoting are normally done quickly in a dry environment, and stock solutions are divided into single-use portions before freezing. Repeated freeze-thaw cycles are avoided because they promote aggregation and can shift the measured content of a vial. These practices are general to synthetic peptides rather than unique to this sequence, but they matter more for short chains kept for long periods.
| Property | Value | Notes |
|---|---|---|
| Purity determination | Reversed-phase HPLC | UV detection commonly at 214 nm |
| Mass confirmation | Mass spectrometry | Compared against theoretical 888.5 Da |
| Powder storage | -20 C or below | Dry and protected from light |
| Reconstituted storage | Aliquoted and frozen | Avoid repeated freeze-thaw cycles |
| Reconstitution solvent | Sterile water or neutral buffer | Avoid extreme pH conditions |
The compound circulates in the literature as a research reagent rather than an approved therapeutic. Regulatory agencies in several countries have not authorized it for medical use, and sporting bodies list related thymosin beta-4 peptides among prohibited substances. Suppliers typically market it with a purity figure and a certificate of analysis, while peer-reviewed clinical reports remain sparse. Discussions therefore often separate laboratory findings from anecdotal reports, and reviewers tend to note the small size and methodological limits of the available studies.
TB-500 refers to a synthetic peptide fragment derived from the actin-binding region of thymosin beta-4, a protein present in most mammalian cells. The full protein contains forty-three amino acids, while the commonly sold fragment is a much shorter acetylated sequence, often cited as LKKTETQ. The fragment retains part of the actin-binding motif but lacks the remainder of the parent protein. Material sold under this name is usually lyophilized powder intended for laboratory research, and it is not a finished pharmaceutical product.
TB-500 is a shorthand label used in supplier catalogs and online discussion for a short synthetic peptide described as a fragment of thymosin beta-4. Most product listings present it as the N-terminally acetylated heptapeptide Ac-LKKTETQ, a sequence corresponding to the actin-binding region of the parent protein. The name is not a formal chemical designation and does not appear in standard nomenclature systems. Because labeling practices vary between vendors, two products sold under the same name may not contain the same molecule, and the stated sequence should be treated as a claim rather than a fixed definition.
Thymosin beta-4 is a naturally occurring protein of 43 amino acids found in most mammalian cells, where it binds actin monomers and influences filament dynamics. It was first isolated from thymus tissue in the early 1980s, and its actin-binding activity was later mapped to a short region near the N-terminus. The synthetic fragment sold as TB-500 was designed to reproduce that region rather than the full protein. Whether a short fragment reproduces the behavior of the intact molecule remains an open question, since the parent protein carries additional structural elements outside the binding region.
Identity and purity are normally assessed with reversed-phase high-performance liquid chromatography, paired with mass spectrometry to confirm molecular mass. A certificate of analysis reports a purity percentage, usually derived from chromatographic peak area, but that figure does not by itself prove a correct sequence or the absence of counterions. Independent verification may include amino acid analysis or peptide mapping. Batch-to-batch variation is a documented concern in the research chemical market, and the gap between a quoted purity value and actual peptide content can be substantial when the material is a salt or retains residual water.
Lyophilized peptide arrives as a dry cake that should stay sealed until use. Reconstitution is generally performed with sterile water or a buffered solution, and the resulting liquid should be handled gently to limit mechanical stress. Repeated freeze-thaw cycles are widely described as harmful to short peptides, so dividing a reconstituted batch into single-use portions is a common practice. Laboratories also record the solvent, concentration, and date of preparation on the vial label to keep later measurements traceable.
Laboratory work on thymosin beta-4 describes binding to monomeric actin and effects on cell migration, angiogenesis, and inflammatory signaling in cultured cells. Animal models have examined skin, corneal, and cardiac repair after injury, with outcomes reported mainly in preclinical literature. Most of that evidence concerns the parent protein rather than preparations labelled TB-500, so extrapolation from animal findings to a specific commercial product remains uncertain. Whether the two behave identically in living systems has not been established in controlled human studies.
No major regulatory agency has approved TB-500 for therapeutic use, and it holds no pharmacopoeial monograph. The name appears on the World Anti-Doping Agency prohibited list within the class covering peptide hormones, growth factors, and related substances. Detection in doping control relies on mass spectrometric methods applied to urine, often after preparation steps that concentrate the analyte. Discussion of TB-500 therefore clusters in biochemistry, sports medicine, and anti-doping literature rather than in registered clinical trials.
=== Africa === In addition to the mummies of Egypt, there have been instances of mummies being discovered in other areas of the African continent. The bodies show a mix of anthropogenic and spontaneous mummification, with some being thousands of years old.
=== Cattle === In dairy cattle, ketosis commonly occurs during the first weeks after giving birth to a calf and is sometimes referred to as acetonemia. This is most likely the result of an energy deficit when intake is inadequate to compensate for the increased metabolic demand of lactating. The elevated β-hydroxybutyrate concentrations can depress gluconeogenesis, feed intake and the immune system, as well as have an impact on milk composition. Point of care diagnostic tests can be useful to screen for ketosis in cattle.
The rate of proteolysis may also depend on the physiological state of the organism, such as its hormonal state as well as nutritional status. In time of starvation, the rate of protein degradation increases.
As a rule, only the external female genitals of placental mammals are referred to as the "vulva", although the term is also used in the scientific literature for functionally comparable structures in other animal groups such as marsupials and roundworms (Nematoda). For comparison, birds, reptiles, amphibians, and monotremes have a cloaca. An organ system that resembles a vulva does not exist for these animals. The vulva of a placental consists of the following along with its variations:
Sources: en.wikipedia.org
Traditional Chinese medicine (TCM) is an alternative medical practice drawn from traditional medicine in China. A large share of its claims are pseudoscientific, with the majority of treatments having no robust evidence of effectiveness or logical mechanism of action. Some TCM ingredients are known to be toxic and cause disease, including cancer. Medicine in traditional China encompassed a range of sometimes competing health and healing practices, folk beliefs, literati theory, Taoist and Confucian philosophy, herbal remedies, food, diet, exercise, medical specializations, and schools of thought. TCM as it exists today has been described as a largely 20th century invention. In the early twentieth century, Chinese cultural and political modernizers worked to eliminate traditional practices as backward and unscientific. Traditional practitioners then selected elements of philosophy and practice and organized them into what they called "Chinese medicine". In the 1950s, the Chinese government sought to revive traditional medicine (including legalizing previously banned practices) and sponsored the integration of Chinese and Western medicine. In the Cultural Revolution of the 1960s, the government promoted TCM as inexpensive and popular. This was largely spearheaded by Mao Zedong, despite the fact that, according to The Private Life of Chairman Mao, he did not believe in its effectiveness. After the opening of relations between the United States and China after 1972, there was great interest in the West for what is now called traditional Chinese medicine (TCM).
The Byzantine Empire, also known as the Eastern Roman Empire, was the continuation of the Roman Empire centred on Constantinople during late antiquity and the Middle Ages. Having survived the fall of the Western Roman Empire in the 5th century AD, it endured until the fall of Constantinople to the Ottoman Empire in 1453. The term 'Byzantine Empire' was coined only after its demise; its citizens used the term 'Roman Empire' and called themselves 'Romans'. During the early centuries of the Roman Empire, the western provinces were Latinised, but the eastern parts kept their Hellenistic culture. Constantine I (r. 324–337) legalised Christianity and moved the capital to Constantinople. Theodosius I (r. 379–395) made Christianity the state religion and Greek gradually replaced Latin for official use. The empire adopted a defensive strategy and, throughout its remaining history, experienced recurring cycles of decline and recovery. The Byzantine Empire reached its greatest extent under the reign of Justinian I (r. 527–565), who briefly reconquered much of Italy and the western Mediterranean coast. A plague began around 541, and a prolonged warfare with Persia placed fiscal and military strain on the empire, contributing to political and strategic challenges in the decades that followed. In the 630s and 640s the Arab conquests defeated Byzantine field armies in Syria and Egypt, resulting in the permanent loss of those provinces to the Rashidun Caliphate. In 698, Africa was lost to the Umayyad Caliphate, but the empire stabilised under the Isaurian dynasty.
Cross linking antibody induced aggregation of Thy1 cause death of thymocytes and mesangial cells mainly by apoptosis despite Bcl2 upregulation. The death of mesangial cells seems to be apoptosis by TUNEL staining or annexin V staining, but electron microscopy suggest it is necrosis.
Nonetheless, John Lennon consistently stated over the course of many years that the fact that the initials of "Lucy in the Sky with Diamonds" spelled out L-S-D was a coincidence (he stated that the title came from a picture drawn by his son Julian) and that the band members did not notice until after the song had been released, and Paul McCartney corroborated that story. John Lennon, George Harrison, and Ringo Starr also used the drug, although McCartney cautioned that "it's easy to overestimate the influence of drugs on the Beatles' music." Michel Foucault had an LSD experience with Simeon Wade in Death Valley and later wrote "it was the greatest experience of his life, and that it profoundly changed his life and his work." According to Wade, as soon as he came back to Paris, Foucault scrapped the second History of Sexuality's manuscript, and totally rethought the whole project. Kary Mullis is reported to credit LSD with helping him develop DNA amplification technology, for which he received the Nobel Prize in Chemistry in 1993. Carlo Rovelli, an Italian theoretical physicist and writer, has credited his use of LSD with sparking his interest in theoretical physics. Oliver Sacks, a neurologist famous for writing best-selling case histories about his patients' disorders and unusual experiences, talks about his own experiences with LSD and other perception altering chemicals, in his book, Hallucinations. Alexander Shulgin, American chemist, told Albert Hofmann that he preferred LSD to 2C-B.
"Fight! Wildcats! Fight!" is the official fight song of the UA. While "Bear Down, Arizona!" is the more recognizable fight song attributed to the university, it was written 23 years after "Fight!" and is now described as the official motto of the Arizona Wildcats. In 1952 Jack K. Lee, the new director of the UA's band, saw the words "BEAR DOWN" written on the university's gymnasium and was inspired to create the music and lyrics for a fight song by that name. The UA fans were delighted when the song was played during athletic events, and "Bear Down, Arizona!" became accepted as the unofficial fight song.
Sources: en.wikipedia.org
Nicergoline, sold under the brand name Sermion among others, is an ergot derivative used to treat senile dementia and other disorders with vascular origins. Internationally it has been used for frontotemporal dementia as well as early onset in Lewy body dementia and Parkinson's dementia. It decreases vascular resistance and increases arterial blood flow in the brain, improving the utilization of oxygen and glucose by brain cells. It has similar vasoactive properties in other areas of the body, particularly the lungs. Unlike many other ergolines, such as ergotamine, nicergoline is not associated with cardiac fibrosis. It is used for vascular disorders such as cerebral thrombosis and atherosclerosis, arterial blockages in the limbs, Raynaud's disease, vascular migraines, and retinopathy. Nicergoline has been registered in over fifty countries and has been used for more than three decades for the treatment of cognitive, affective, and behavioral disorders of older people.
== Ecology == Maqui berries are a favored food for birds at the end of summer. Deforestation of the Valdivian temperate forests in Chile suppresses seed dispersal by birds and leads to inbreeding depression. It is viewed as an invasive species in the Juan Fernandez Islands.
under the joint auspices of the George Washington University and the Carnegie Institution of Washington. There, the news on nuclear fission was spread even further, which fostered many more experimental demonstrations. The 6 January 1939 Hahn and Strassman paper announced the discovery of fission. In their second publication on nuclear fission in February 1939, Hahn and Strassmann used the term Uranspaltung (uranium fission) for the first time, and predicted the existence and liberation of additional neutrons during the fission process, opening up the possibility of a nuclear chain reaction. The 11 February 1939 paper by Meitner and Frisch compared the process to the division of a liquid drop and estimated the energy released at 200 MeV. The 1 September 1939 paper by Bohr and Wheeler used this liquid drop model to quantify fission details, including the energy released, estimated the cross section for neutron-induced fission, and deduced 235U was the major contributor to that cross section and slow-neutron fission.
Genetic engineering was now on the scientific agenda, as it was becoming possible to identify genetic characteristics with diseases such as beta thalassemia and sickle-cell anemia. Responses to scientific achievements were colored by cultural skepticism. Scientists and their expertise were looked upon with suspicion. In 1968, an immensely popular work, The Biological Time Bomb, was written by the British journalist Gordon Rattray Taylor. The author's preface saw Kornberg's discovery of replicating a viral gene as a route to lethal doomsday bugs. The publisher's blurb for the book warned that within ten years, "You may marry a semi-artificial man or woman…choose your children's sex…tune out pain…change your memories…and live to be 150 if the scientific revolution doesn’t destroy us first." The book ended with a chapter called "The Future – If Any." While it is rare for current science to be represented in the movies, in this period of "Star Trek", science fiction and science fact seemed to be converging. "Cloning" became a popular word in the media. Woody Allen satirized the cloning of a person from a nose in his 1973 movie Sleeper, and cloning Adolf Hitler from surviving cells was the theme of the 1976 novel by Ira Levin, The Boys from Brazil. In response to these public concerns, scientists, industry, and governments increasingly linked the power of recombinant DNA to the immensely practical functions that biotechnology promised.
Sources: en.wikipedia.org
The lyophilised powder is typically held at -20 C or lower in a dry, dark place. Reconstituted solutions are aliquoted and frozen to avoid repeated freeze-thaw cycles.
Mass spectrometry is the usual confirmatory method because it measures the intact mass. Reversed-phase chromatography is used alongside it to estimate purity.
Not directly. Reported percentages depend on the chromatographic method, detection wavelength, and integration criteria, so the underlying method details matter.
Divide it into single-use aliquots and hold them frozen at -20 °C or below, protected from light. Repeated thawing of one container is the main avoidable source of variability.