A practical reference on Reversed-phase HPLC: what it is, how it behaves, what the literature reports, and where the honest uncertainties sit.
This page was last updated on 2025-07-26 and is reviewed periodically as new material appears.
Thymosin alpha-1 is a synthetic peptide of 28 amino acid residues that corresponds to a naturally occurring fragment first isolated from thymus tissue. Its chain is acetylated at the amino terminus, a modification that shields the peptide from rapid cleavage by aminopeptidases. The molecule carries a net negative charge at physiological pH and dissolves freely in water. Researchers classify it as an immune-modulating agent rather than a classical hormone, because it acts on several cell types of both the innate and the adaptive immune system.
The peptide was identified during work in the 1970s on thymosin fraction 5, a partially purified extract of calf thymus. Investigators separated that mixture and characterized individual components, one of which they named thymosin alpha-1. The same compound later received the international nonproprietary name thymalfasin. Commercial material is produced by solid-phase peptide synthesis rather than by extraction, so synthetic and natural forms share an identical sequence. Naming conventions vary across the literature, and readers should distinguish the alpha-1 peptide from other thymosins that have unrelated sequences and functions.
Thymosin beta-4 is a separate 43-residue peptide that binds actin and participates in cell migration; it shares no sequence similarity with thymosin alpha-1 despite the common family name. Other preparative materials, such as thymosin fraction 5 and thymopoietin, contain distinct mixtures or peptides. The shared thymosin label reflects the tissue of origin used in early purification, not a common structural core. Treating these molecules as interchangeable is a frequent source of confusion in laboratory reports and in popular summaries alike.
Identity and purity are assessed mainly by reversed-phase high-performance liquid chromatography, which separates the peptide from closely related impurities and from truncated or oxidized variants. Mass spectrometry supplies the molecular mass and confirms the expected sequence length, while amino acid analysis can be used to check composition. Because the molecule has no chromophore beyond the peptide backbone, ultraviolet detection is typically performed at a low wavelength, where baseline interference from solvents and buffers is a practical concern. Water content and counter-ion content are often reported alongside purity.
Practical handling focuses on limiting adsorption and contamination. The peptide dissolves readily in water, and dilute solutions tend to adhere to plastic and glass surfaces, so an inert carrier protein or a defined buffer can reduce losses in laboratory work. Workers also record the counter-ion form, since an acetate or trifluoroacetate salt changes the mass balance of the weighed powder. Documentation of lot number, purity value, and storage history supports reproducibility when results from different laboratories are compared.
| Property | Value | Notes |
|---|---|---|
| Molecular mass | About 3.1 kDa | 28 residues, N-terminally acetylated |
| Appearance | White to off-white powder | Lyophilized solid |
| Solubility | Freely soluble in water | Also soluble in aqueous buffers |
| Storage temperature | 2 to 8 °C | Protect from light and moisture |
| Common synonyms | Thymalfasin; Tα1 | Same peptide sequence |
Identity and purity are usually assessed by reversed-phase high-performance liquid chromatography, which separates the target peptide from truncated or chemically modified byproducts. Mass spectrometry confirms the expected molecular mass and can indicate acetylation state or sequence errors. Amino acid analysis and peptide mapping supply complementary sequence-level information, while endotoxin testing is relevant for preparations intended for cell or animal work. Purity figures reported by suppliers refer to the method used and are not directly comparable across laboratories unless conditions are stated.
Lyophilized material is typically treated as a hygroscopic solid that should be brought to room temperature before the container is opened, which limits condensation on the powder. Reconstitution is commonly done with sterile water or a buffered diluent, and gentle mixing is preferred over vigorous agitation to reduce foaming and surface adsorption. Because peptides can bind to plastic and glass, diluents containing a small amount of carrier protein are sometimes used in laboratory work. Working solutions are generally aliquoted and prepared fresh rather than subjected to repeated freezing and thawing.
Stability depends on temperature, pH, and the number of freeze-thaw events the sample has experienced. Freeze-dried material is commonly held at -20 °C or colder, while reconstituted liquid is kept cold and used within a short window. Extreme pH and prolonged light exposure can promote deamidation, oxidation, or aggregation, particularly at asparagine and methionine positions. Adsorption to container walls can lower the measured concentration of a dilute solution even when the peptide molecules themselves remain intact.
Identity and purity testing for thymosin alpha 1 relies mainly on reversed-phase high-performance liquid chromatography and mass spectrometry. Chromatography separates the parent peptide from truncated or modified variants, while mass spectrometry confirms the expected molecular mass. Amino acid analysis and peptide mapping provide additional sequence confirmation. Counterion content, water content, and residual solvents are measured separately as part of specification testing. No single method captures every attribute, so laboratories combine several techniques.
The peptide lacks cysteine, methionine, and tryptophan, so disulfide scrambling and sulfur oxidation are not major degradation routes. Instead, aspartate residues can undergo isomerization or cyclization to succinimide intermediates, generating isoaspartate variants. Hydrolysis of peptide bonds also occurs slowly in solution. These changes may reduce biological activity even when the main peak remains detectable. Stability studies therefore track both potency and the appearance of related substances.
Thymosin alpha-1 is a 28-residue peptide first isolated from thymus tissue in the 1970s. It corresponds to the N-terminal portion of thymosin beta-4, from which it is cleaved in vivo. The peptide carries an acetyl group at its N-terminus, a modification that affects its charge and stability. Synthetic material produced by solid-phase peptide synthesis is chemically identical to the natural fragment and is the form used in research and clinical studies.
Laboratory work indicates that the peptide acts on cells of both the innate and adaptive immune systems. Reported effects include signalling through Toll-like receptors on dendritic cells, enhanced T-cell maturation, and increased natural killer cell activity. These actions are described largely from cell-culture and animal experiments, and the precise receptor-level events remain incompletely defined. Studies in humans have generally measured immune markers rather than a single defined molecular target. The resulting picture remains partly descriptive.
=== The World Wars === With the rest of the Marshalls, Enewetak was captured by the Imperial Japanese Navy in 1914, during World War I and mandated to the Empire of Japan by the League of Nations in 1920. The Japanese administered the island under the South Seas Mandate, but mostly left affairs in hands of traditional local leaders until the start of World War II. The atoll, together with other parts of Marshall Islands located to the west of 164°E, was placed under the governance of Pohnpei district during the Japanese administration period, separately from the rest of the Marshall Islands.
== Treatment == Antibiotics are the primary treatment. The specific approach to their use is dependent on the individual affected and the stage of the disease. For most people with early localized infection, oral administration of doxycycline is widely recommended as the first choice, as it is effective against not only Borrelia bacteria but also a variety of other illnesses carried by ticks. People taking doxycycline should avoid sun exposure because of higher risk of sunburns. Doxycycline is contraindicated in children younger than eight years of age and women who are pregnant or breastfeeding; alternatives to doxycycline are amoxicillin, cefuroxime axetil, and azithromycin. Azithromycin is recommended only in case of intolerance to the other antibiotics. The standard treatment for cellulitis, cephalexin, is not useful for Lyme disease. When it is unclear if a rash is caused by Lyme or cellulitis, the IDSA recommends treatment with cefuroxime or amoxicillin/clavulanic acid, as these are effective against both infections. Individuals with early disseminated or late Lyme infection may have symptomatic cardiac disease, Lyme arthritis, or neurologic symptoms like facial palsy, radiculopathy, meningitis, or peripheral neuropathy. Intravenous administration of ceftriaxone is recommended as the first choice in these cases; cefotaxime and doxycycline are available as alternatives. Treatment regimens for Lyme disease range from 7–14 days in early localized disease, to 14–21 days in early disseminated disease, to 14–28 days in late disseminated disease.
Lieutenant-Col Pigott was invalided on 12 August and Maj Eardley-Wilmot took over command, later being promoted to Lt-Col. 40th Division was relieved at the end of October and moved south to join Fourth Army in the Somme sector. Three weeks' training was first carried out around Abbeville, with 12th Suffolks billeted at Berneuil, then by road and rail to the area west of Bray-sur-Somme, with 12th Suffolks at Mouflers. The division then went into the line at the end of December, with 121st Bde initially in reserve, 12th Suffolks in 'Camp 17' at Suzanne. On 31 December 12th Suffolks took over the front line at Bouchavesnes. Here there was complete destruction left by that summer's fighting. The front line troops spent the winter among a maze of smashed and flooded trenches, under occasional bombardments. Living in these conditions the number of sick and cases of Trench foot rose sharply. Due to the lack of fit replacements, the Bantam concept was abandoned during the winter of 1916-17 and thereafter reinforcements to the battalion (unless they were returning wounded) were of normal height.
== Nitrogen-13 == Nitrogen-13 (13N) has a half-life of a little under ten minutes. It is produced in the atmosphere when gamma rays (for example from lightning) knock neutrons out of nitrogen-14. 13N decays to 13C, emitting a positron. The positron quickly annihilates with an electron, producing two gamma rays of about 511 keV. After a lightning bolt, this gamma radiation dies down with a half-life of 10 minutes, but these low-energy gamma rays go on average only about 90 metres through the air, so they may only be detected for a minute or so as the "cloud" of 13N and 15O floats by, carried by the wind. Nitrogen-13 plays a significant role in the CNO cycle, which is the dominant source of energy in main sequence stars more massive than 1.5 times the mass of the Sun. Nitrogen-13 is used in positron emission tomography in the form of 13N-labelled ammonia, for example for myocardial perfusion imaging. It can be produced with a medical cyclotron, using a target of pure water with a trace amount of ethanol. The reactants are oxygen-16 (present as H2O) and a proton, and the products are nitrogen-13 and an alpha particle (helium-4):
Sources: en.wikipedia.org
==== Effects ==== In accordance with their psychedelic effects in humans, the 2C drugs produce the head-twitch response and wet dog shakes, behavioral proxies of psychedelic effects, in rodents. At least some 2C drugs, such as 2C-D and 2C-E, produce hyperlocomotion at lower doses in rodents. All 2C drugs produce hypolocomotion at higher doses in rodents. 2C drugs, including 2C-C, 2C-D, 2C-E, and 2C-I, substitute partially to fully for psychedelics like DOM, DMT, and LSD and/or for the entactogen MDMA in rodent drug discrimination tests. However, none of the assessed 2C drugs substituted for dextromethamphetamine, suggesting that they lack amphetamine-type or stimulant-like effects. In contrast to most psychedelics, at least two assessed 2C drugs, 2C-C and 2C-P, have shown reinforcing effects in rodents, including conditioned place preference (CPP) and self-administration. The mechanism by which these effects are mediated is unknown. However, it may be related to reduced expression of the dopamine transporter (DAT) and increased DAT phosphorylation, in turn resulting in increased extracellular dopamine levels in certain brain areas. These 2C drugs might have misuse potential in humans. Similar reinforcing effects in animals have been observed for NBOMe analogues of 2C drugs, including 25B-NBOMe, 25D-NBOMe, 25E-NBOMe, 25H-NBOMe, and 25N-NBOMe. Similarly to DOI, tolerance has been found to gradually develop to the head-twitch response induced by 2C-T-7 with chronic administration in rodents.
One important use of American kestrels is in falconry. It is often considered a beginner's bird, though the careful weight control needed to maintain the kestrel's desire to aggressively hunt takes skill. Falconers experienced in extracting the best performance the species is capable of, report they are highly reliable on the normal game of sparrows and starlings. More aggressive individuals are sometimes capable of capturing prey up to approximately twice their own body weight, allowing the occasional capture of true game birds such as quail and dove. However, most falconers interested in the reliable taking of such game do prefer larger falcons or hawks. The advantage the American kestrel offers the experienced falconer is its suitability to simple and urban falconry not requiring large tracts of land or the use of hunting dogs. This form of falconry is sometimes referred to as "micro-falconry" or "micro-hawking". The other small raptor species commonly used in micro-falconry are the merlin, the sharp-shinned hawk (the smallest Accipiter), and the European kestrel (a true kestrel). Hawking with the American kestrel requires adapting to the strengths and weaknesses of the bird. It is a tiny falcon, and even for its size, it is less muscular than other small falcons such as the athletic and swift merlin. It is more adapted to ambush hunting and short chases than to the longer aerial chases larger falcons often adopt. Used within its limits, it is effective.
In Britain, a half and half may mean a mixture of mild ale and bitter. In the North East of England, a request for a half and half would more commonly produce a combination of Scotch ale and India pale ale (IPA). This drink fell from favour when the Scottish & Newcastle brewery was obliged to sell many of their tied public houses and McEwan's Scotch and IPA disappeared from public bars across the North East. In Canada and the United States, Black and Tan refers to Guinness and a lager or ale that will support the Guinness, most commonly Bass Ale, although some Irish-themed bars shun the term for its association with the Royal Irish Constabulary's "Black and Tans" force. A Half and Half is Guinness and Harp. A Guinness and Smithwick's is a Blacksmith.
Biden was elected the 46th president in November 2020, defeating the incumbent, Donald Trump. Trump and numerous other Republicans repeatedly made false claims that widespread electoral fraud had occurred and that only he had legitimately won the election. Biden's transition was delayed by several weeks as the White House ordered federal agencies not to cooperate. On November 23, General Services Administrator Emily W. Murphy formally recognized Biden as the apparent winner of the 2020 election and authorized the start of a transition process to the Biden administration. Although most resulting lawsuits were either dismissed or ruled against by numerous courts, Trump nonetheless conspired with his campaign team to submit documents in several states (all of which Biden had won) that falsely claimed to be legitimate electoral votes for President Trump and Vice President Mike Pence. After the submission of these documents, the Trump campaign intended that the presiding officer of the United States Senate, either President of the Senate Pence or President pro tempore Chuck Grassley, would claim the unilateral power to reject electors during the January 6, 2021, vote counting session; the presiding officer would reject all electors from the several states for which the Trump campaign had submitted false documents, leaving 232 votes for Trump and 222 votes for Biden, thereby overturning the election results in Trump's favor. This plan failed after Pence refused to cooperate with it.
Blood dyscrasias (e.g., agranulocytosis, leukopenia, and neutropaenia), which is more common in patients on clozapine. Metabolic syndrome and other metabolic problems such as type II diabetes mellitus — particularly common with clozapine, olanzapine and zotepine. In American studies African Americans appeared to be at a heightened risk for developing type II diabetes mellitus. Evidence suggests that females are more sensitive to the metabolic side effects of first-generation antipsychotic drugs than males. Metabolic adverse effects appear to be mediated by antagonizing the dopamine D2, the histamine H1 and serotonin 5-HT2C receptors and perhaps by interacting with other neurochemical pathways in the central nervous system. Neuroleptic malignant syndrome, a potentially fatal condition characterized by: Autonomic instability, which can manifest with tachycardia, nausea, vomiting, diaphoresis, etc. Hyperthermia — elevated body temperature. Mental status change (confusion, hallucinations, coma, etc.) Muscle rigidity Laboratory abnormalities (e.g., elevated creatine kinase, reduced iron plasma levels, electrolyte abnormalities, etc.) Pancreatitis QT interval prolongation — more prominent in those treated with amisulpride, pimozide, sertindole, thioridazine and ziprasidone. Torsades de pointes Seizures, particularly in people treated with chlorpromazine and clozapine. Thromboembolism Myocardial infarction Stroke Pisa syndrome Some atypical antipsychotics are associated with considerable weight gain, diabetes, and the risk of metabolic syndrome.
Sources: en.wikipedia.org
== Function == Urocanic acid is found in animal sweat and skin. its concentration varies greatly between people, from 4 nM per cm2 to 34 nM per cm2 with only small differences between areas other than at the sole of the foot and between sun-exposed and unexposed areas. Concentration does not link with age, sex, skin tone, photosensitivity, and stratum corneum thickness. Among other functions, urocanic acid acts as an endogenous sunscreen or photoprotectant against UVB-induced DNA damage. However, some studies have questioned this. Urocanic acid is found predominantly in the stratum corneum of the skin and it is likely that most of it is derived from filaggrin catabolism (a histidine-rich protein). When exposed to UVB irradiation, trans-urocanic acid is converted in vitro and in vivo to cis-urocanic acid (cis-UCA). The cis form is known to activate regulatory T cells. Measuring cis-UCA provides a sensitive means at sub-erythemal doses to detect UVB, and so offers a potential method to assess the UVR protection provided by suncreams. Some studies attribute filaggrin an important role in keeping the skin surface slightly acidic, through a breaking down mechanism to form histidine and subsequently trans-urocanic acid, however others have shown that the filaggrin–histidine–urocanic acid cascade is not essential for skin acidification.
In response to the presence of Navy warships in Latin America, two Venezuelan BMA F-16 fighter jets flew over the USS Jason Dunham on 4 September. The US Department of Defense called it "highly provocative" and deployed ten F-35 fighter jets and two MQ-9 Reaper drones to Puerto Rico. That same day Marco Rubio, the US Secretary of State, met with President of Ecuador Daniel Noboa in Quito; Rubio stated that Trump intended to "wage war" on those that have "been waging war on us for 30 years" and designated the gangs Los Lobos and Los Choneros as narco terrorists, with Noboa's agreement. On 23 September, the United States added the 18th Street gang, which is largely based in the Caribbean coastal nations of Guatemala and Honduras, to the designated foreign terrorists list. The Venezuelan government stated on 12 September that a US destroyer had detained and boarded a tuna fishing boat with nine crew members. The destroyer eventually released the boat, and it was escorted away by the Venezuelan Navy. Minister of Foreign Affairs Yván Gil described the act as illegal and said that Venezuela would defend itself.
=== Endoscopy === After Edlich learned about endoscopes in Asia, he received an endoscope for gastroscopic visualization of the patient's stomach. As a surgical resident, Edlich was the first physician to do a gastroscopy at the University of Minnesota Medical Center. Edlich's picture was featured on the cover of Postgraduate Medicine, the Journal of Applied Medicine, in November 1968. His experiences with gastroscopy led to the first minimally invasive surgical procedure at the University of Minnesota Hospital, an endoscopic gastrostomy. Edlich soon realized the limitations of the thick, narrow-diameter latex Ewald tubes that were being used to evacuate blood clots from the patient's stomach before endoscopic examination. Edlich devised a thin-walled, transparent, plastic tube for evacuation of blood clots from a patient's stomach.
Beginning with his January 29, 2002 State of the Union address, Bush began publicly focusing attention on Iraq, which he labeled as part of an "axis of evil" allied with terrorists and posing "a grave and growing danger" to U.S. interests through possession of weapons of mass destruction. In the latter half of 2002, CIA reports contained assertions of Saddam Hussein's intent of reconstituting nuclear weapons programs, not properly accounting for Iraqi biological and chemical weapons, and that some Iraqi missiles had a range greater than allowed by the UN sanctions. Contentions that the Bush Administration manipulated or exaggerated the threat and evidence of Iraq's weapons of mass destruction capabilities would eventually become a major point of criticism for the president. In late 2002 and early 2003, Bush urged the United Nations to enforce Iraqi disarmament mandates, precipitating a diplomatic crisis. In November 2002, Hans Blix and Mohamed ElBaradei led UN weapons inspectors in Iraq, but were advised by the U.S. to depart the country four days prior to the U.S. invasion, despite their requests for more time to complete their tasks. The U.S. initially sought a UN Security Council resolution authorizing the use of military force but dropped the bid for UN approval due to vigorous opposition from several countries. The Bush administration's claim that the Iraq War was part of the war on terror had been questioned and contested by political analysts.
Sources: en.wikipedia.org
It is a 28-residue synthetic peptide studied as an immune-modulating agent and approved as a drug in some countries. The sequence matches a naturally occurring fragment isolated from thymus tissue. It is not a hormone in the endocrine sense.
The name traces back to thymosin fraction 5, a crude thymus extract examined in the 1970s. Individual peptides in that mixture were labeled with Greek letters, and alpha-1 was one of them. The international nonproprietary name thymalfasin was assigned later.
No. Thymosin beta-4 contains 43 residues and binds actin, while thymosin alpha-1 contains 28 residues and acts on immune cells. The two sit in a historical naming group but share no sequence similarity, and they are not substitutes for one another.
Cool storage below freezing is usual for long-term retention, with a desiccant and protection from light. Portions are often split before first use to avoid repeated handling.