A practical reference on freeze-thaw: what it is, how it behaves, what the literature reports, and where the honest uncertainties sit.
This page was last updated on 2026-06-21 and is reviewed periodically as new material appears.
Because REV-ERB receptors are core clock components, SR9009 has been examined for effects on daily rhythms as well as metabolism. Research has explored whether the compound can shift or reinforce circadian gene expression in tissues such as liver and muscle. Some studies report improved metabolic markers in obese or diabetic mice, while others show context-dependent responses. Questions remain about which effects are direct, which are secondary to timing, and how they might differ across species.
SR9009 is a synthetic small molecule studied as an agonist of REV-ERB nuclear receptors. REV-ERB alpha and REV-ERB beta help regulate circadian rhythms and metabolic gene expression. In laboratory research, SR9009 has been used to probe how these receptors affect skeletal muscle, liver, and adipose tissue. The compound was identified in academic drug-discovery work and is often described in scientific literature by its chemical name and research code. It is not an approved medicine, and human clinical data remain limited or absent.
Physicochemical behavior influences handling. SR9009 is described as a solid with limited aqueous solubility, so organic solvents such as dimethyl sulfoxide or ethanol are common in research stock solutions. Aqueous dilution can produce precipitates if the organic content is too low. Light, heat, and repeated freeze-thaw cycles may affect stability. Storage recommendations usually specify a desiccated freezer environment protected from light, but exact stability data depend on the formulation and matrix.
Detection in biological samples can be complicated by rapid metabolism and low circulating concentrations. Some studies report phase I and phase II metabolites, and analytical methods may need to target those species in addition to the parent compound. Immunoassays are not broadly available, so mass spectrometry remains the main confirmatory approach. For anti-doping testing, laboratories look for SR9009 and its metabolites using validated LC-MS methods. Open questions include how long metabolites remain detectable and how different routes of administration alter detection windows.
In laboratory settings, SR9009 is typically characterized by liquid chromatography–mass spectrometry (LC-MS) or high-performance liquid chromatography with ultraviolet detection (HPLC-UV). These methods can confirm identity and estimate purity, but they require reference standards for accurate quantification. Because SR9009 is not a licensed pharmaceutical, no harmonized pharmacopeial monograph exists. Laboratories often validate in-house methods for matrices such as plasma, urine, or cell culture media. Sample preparation may involve protein precipitation or liquid-liquid extraction before analysis.
| Property | Value | Notes |
|---|---|---|
| Chemical class | Synthetic REV-ERB agonist | Small-molecule nuclear receptor ligand |
| Appearance | Off-white to pale yellow solid | Typical for research-grade powder |
| Solubility class | Soluble in DMSO; low water solubility | Common stock solutions use organic solvent |
| Typical stock solvent | Dimethyl sulfoxide | Used for laboratory assays |
| Common analytical method | HPLC with UV or mass detection | Used for identity and purity checks |
For long-term storage, SR9009 is typically kept as a solid at low temperature, protected from moisture and light. Desiccated conditions limit hydrolysis, while opaque containers reduce photochemical breakdown. Solutions are less stable than solids and are often stored frozen in aliquots to avoid repeated freeze-thaw cycles. Stability data are not standardized across all suppliers, so users should rely on certificate-of-analysis information when available. Degradation may appear as color change, precipitate, or decreased chromatographic purity.
Laboratory identification of SR9009 typically relies on chromatographic separation coupled to mass spectrometry, often with ultraviolet detection as a secondary check. Nuclear magnetic resonance spectroscopy can confirm molecular structure when a reference standard is available. Because many suppliers sell the compound as a research chemical, independent identity testing is important for experimental reproducibility. A single retention time is not sufficient proof of identity, especially when related compounds may be present. Purity assessments usually report a percentage based on area normalization.
Mechanistically, SR9009 binds the ligand-binding domain of REV-ERBα/β and enhances recruitment of corepressor complexes. This represses target genes rather than activating them. Because REV-ERB proteins normally compete with ROR proteins at shared response elements, the net effect depends on tissue and timing. Researchers use SR9009 to probe how nuclear receptor signaling links the clock to metabolism, inflammation, and muscle biology. Findings are largely preclinical, and the precise contribution of each receptor subtype remains under study.
SR9009 is frequently discussed in fitness and research-chemical contexts, yet it has no approved medical indication. Regulatory agencies have not authorized it for human use, and it is not a standard prescription drug. Some sports organizations list it as a prohibited substance because of its potential performance-enhancing properties. Published human data are sparse, so claims about its effects in people often rely on animal models or anecdotal reports. Quality and identity of online materials can vary widely.
SR9009 is a synthetic small molecule studied as an agonist of the nuclear receptors REV-ERBα and REV-ERBβ. It is not a steroid, peptide, or natural hormone. In scientific literature, it appears under the code SR9009 and in non-scientific contexts as Stenabolic. The compound was identified through chemical screening efforts aimed at targeting circadian clock components. Its status remains investigational, and no regulatory agency has approved it as a human medicine.
REV-ERB proteins help regulate daily cycles in gene expression, including genes tied to lipid and glucose metabolism. SR9009 binds these receptors and alters their activity in cell and animal experiments. Consequences observed in rodents include changes in skeletal muscle oxidative capacity, blood lipid levels, and exercise performance. The precise chain from receptor occupancy to whole-body effects is still an active area of study. Human responses cannot be assumed from rodent data.
=== Do–Dy === Martha Doan (1872–1960), American chemist who studied thallium compounds William von Eggers Doering (1917–2011), American chemist known for the total synthesis of quinine Edward Doisy (1893–1986), American biochemist, winner of the 1943 Nobel Prize in Physiology or Medicine Davorin Dolar (1921–2005), Slovenian physical chemist who studied polyelectrolyte solutions, and is regarded as a founder of modern physical chemistry teaching in Slovenia Vy Maria Dong (born 1976), American chemist who studies enantioselective catalysis and natural product synthesis David Adriaan van Dorp (1915–1995), Dutch chemist known for the first full synthesis of vitamin A Israel Dostrovsky (1918–2010), Russian (Ukraine)-born Israeli physical chemist known for separating oxygen isotopes in water Herbert Henry Dow (1866–1930), American industrial chemist, known for bromine extraction Cornelius Drebbel (1572–1633), Dutch inventor, alchemist and chemist who contributed to develop measurement and control systems, optics and chemistry Jean Baptiste Dumas (1800–1884), French chemist, best known for the determination of atomic and molecular masses weights by measuring vapor densities Helen Dyer (1895–1998), American biochemist and early cancer researcher known for studies of carcinogenesis mechanisms
=== Ectopic fat === Ectopic fat is the storage of triglycerides in tissues other than adipose tissue, that are supposed to contain only small amounts of fat, such as the liver, skeletal muscle, heart, and pancreas. This can interfere with cellular functions and hence organ function and is associated with insulin resistance in type 2 diabetes. It is stored in relatively high amounts around the organs of the abdominal cavity, but is not to be confused with visceral fat. The specific cause for the accumulation of ectopic fat is unknown. The cause is likely a combination of genetic, environmental, and behavioral factors that are involved in excess energy intake and decreased physical activity. Substantial weight loss can reduce ectopic fat stores in all organs and this is associated with an improvement of the function of those organs. In the latter case, non-invasive weight loss interventions like diet or exercise can decrease ectopic fat (particularly in heart and liver) in overweight or obese children and adults.
Cerebral creatine deficiencies (CCDs) are a small group of inherited disorders that result from defects in creatine biosynthesis and transport. Commonly affected tissues include the brain and muscles. There are three distinct CCDs. The most common is creatine transporter deficiency (CTD), an X-linked disorder caused by pathogenic variants in creatine transporter SLC6A8. The main symptoms of CTD are intellectual disability and developmental delay, and these are caused by a lack of creatine in the brain, due to the defective transporter. There are also two enzymatic defects of creatine biosynthesis, arginine:glycine amidinotransferase deficiency (AGAT deficiency), caused by variants in GATM gene and guanidinoacetate methyltransferase deficiency (GAMT deficiency), caused by variants in GAMT gene. The two single enzyme defects are both inherited in an autosomal recessive manner.
Following his loss to Sylvia in May, Pudzianowski signed to face former heavyweight boxer and kickboxer Eric Esch, better known as 'Butterbean', at KSW 14 on 18 September. After several brief standup exchanges, Pudzianowski secured a takedown early in the fight and was then able to dominate Esch with ground and pound. Esch, unable to get back to his feet during the attack, tapped out to the strikes, making Pudzianowski the winner by submission at 1:15 of the first round. He came into the fight notably slimmer, having lost around 20 lbs from his previous fight. Many believe his large muscle mass to have caused his stamina problems in his earlier fights. On 21 May 2011 Pudzianowski fought James Thompson at KSW 16, losing by arm triangle. In September 2011 Mariusz Pudzianowski started professional training in the well known MMA camp in the USA – American Top Team. Pudzianowski fought on the KSW 17 event, which was held on 26 November 2011. He faced James Thompson in a rematch. He won the fight via majority decision. This decision caused controversy as Thompson had virtually full control in both rounds, and after the fight Thompson, who was clearly angered by the decision, took the microphone from the announcer and launched a verbal assault directed at the promotion in which he ranted: "F...g joke. Give Mariusz a big round of applause. Come on. What a f...g joke. I thought KSW was really trying to be serious.
Sources: en.wikipedia.org
Hepcidin is a regulator of iron metabolism. It inhibits iron transport by binding to the iron export channel ferroportin which is located in the basolateral plasma membrane of gut enterocytes and the plasma membrane of reticuloendothelial cells (macrophages), ultimately resulting in ferroportin breakdown in lysosomes. It has been shown that hepcidin is able to bind to the central cavity of ferroportin, thus occluding iron export from the cell. This suggests that hepcidin is able to regulate iron export independently of ferroportin endocytosis and ubiquitination, and is thus quickly inducible and reversible. In enterocytes, this prevents iron transmission into the hepatic portal system, thereby reducing dietary iron absorption. In macrophages, ferroportin inhibition causes iron be to stored within the cell. Increased hepcidin activity is partially responsible for reduced iron availability seen in anemia of chronic inflammation, such as kidney failure; this may explain why patients with end stage kidney failure may not respond to oral iron replacement. Any one of several mutations in hepcidin will result in juvenile hemochromatosis. The majority of juvenile hemochromatosis cases are caused by mutations in hemojuvelin. Mutations in TMPRSS6 can cause anemia through dysregulation of hepcidin. Hepcidin has strong antimicrobial activity against Escherichia coli strain ML35P and Neisseria cinerea and weaker antimicrobial activity against Staphylococcus epidermidis, Staphylococcus aureus and Streptococcus agalactiae.
Robert Fripp – guitar, keyboards, Mellotron, electronics (1968–1974, 1981–1984, 1994–2008, 2013–2021) Mel Collins – saxophones, flute, bass flute, clarinet, bass clarinet, Mellotron, backing vocals (1970–1972, 2013–2021) Tony Levin – bass guitar, Chapman Stick, upright bass, synthesisers, backing vocals (1981–1984, 1994–1999, 2003–2008, 2013–2021) Pat Mastelotto – drums, percussion, programming (1994–2008, 2013–2021) Gavin Harrison – drums, percussion (2007–2008, 2013–2021) Jakko Jakszyk – lead vocals, guitar, flute, keyboards (2013–2021) Jeremy Stacey – drums, keyboards, backing vocals (2016–2021)
== Awards and honours == Uhlmann was elected a Fellow of the Royal Society (FRS) in 2015. His certificate of election reads: Frank Uhlmann's discovery with Nasmyth of 'separase', the protease that cleaves the cohesive links between sister chromatids to trigger anaphase is a key contribution to our understanding of the cell cycle. He has made major contributions to our understanding of the mechanisms of sister chromatid cohesion, and their relationship to cell cycle regulation. He generated the first chromosome-wide high resolution maps of proteins involved in chromosome packaging and segregation. He showed that yeast cohesins accumulate at sites of converging transcription distinct from the sites where their loading factors bind, apparently reflecting interaction with the transcription apparatus; and that cohesin loading factors are recruited to specific chromosomal sites through interaction with the nucleosome remodelling complex Rsc. He has identified genes required for cohesion establishment, and shown that one of these, EcoI, acetylates cohesin during DNA replication, thereby locking it onto DNA and his studies of the link between cohesion regulation and the cell cycle have shown that as well as cleaving cohesin, separase promotes mitotic exit by activating the Cdc14 phosphatase in a protease-independent manner. In 2006, Uhlmann was also elected a member of the European Molecular Biology Organization (EMBO) and awarded the EMBO Gold Medal.
== Function == In a biological context, ROS are byproducts of the normal metabolism of oxygen. ROS have roles in cell signaling and homeostasis. ROS are intrinsic to cellular functioning, and are present at low and stationary levels in normal cells. In plants, ROS are involved in metabolic processes related to photoprotection and tolerance to various types of stress. However, ROS can cause irreversible damage to DNA as they oxidize and modify some cellular components and prevent them from performing their original functions. This suggests that ROS has a dual role; whether they will act as harmful, protective or signaling factors depends on the balance between ROS production and disposal at the right time and place. In other words, oxygen toxicity can arise both from uncontrolled production and from the inefficient elimination of ROS by the antioxidant system. ROS are intermediates in the redox behavior of O2, which is central to fuel cells. During times of environmental stress (e.g., UV or heat exposure), ROS levels can increase dramatically. This may result in significant damage to cell structures. Cumulatively, this is known as oxidative stress. The production of ROS is strongly influenced by stress factor responses in plants, these factors that increase ROS production include drought, salinity, chilling, defense of pathogens, nutrient deficiency, metal toxicity and UV-B radiation. ROS are also generated by exogenous sources such as ionizing radiation generating irreversible effects in the development of tissues in both animals and plants.
More generally, this synthesis occurs in three stages, with the first stage taking place in the cytoplasm and the second and third stages occurring in the endoplasmic reticulum. The stages are as follows:
Sources: en.wikipedia.org
He has said he believes in God, but not necessarily in a traditional way: "I think everyone believes in God in their own ways", he said. "To me, it means that all of us are connected, all of life is connected, and that we are all tied together." In October 2015, on the late-night talk show Jimmy Kimmel Live!, Kimmel asked him, "You say you are culturally Jewish and you don't feel religious; do you believe in God and do you think that's important to the people of the United States?" Sanders replied:
=== Buffer === Buffer creates an environment for isolated proteins. Each buffer choice has a specific pH range, so the buffer should be chosen based on whether the experiment's target protein is stable under a certain pH. Also, for buffers with similar pH ranges, it is important to consider whether the buffer is compatible with the experiment's target protein. The table below contains several most commonly used buffers and their pH ranges.
==== Barriers to breastfeeding ==== Breastfeeding is noted as one of the most cost-effective medical interventions benefiting child health. While there are considerable differences among developed and developing countries, there are universal determinants of whether a mother breastfeeds or uses formula; these include income, employment, social norms, and access to healthcare. Many newly made mothers face financial barriers; community-based healthcare workers have helped to alleviate these barriers, while also providing a viable alternative to traditional and expensive hospital-based medical care. Recent studies, based upon surveys conducted from 1995 to 2010, show that exclusive breastfeeding rates have risen globally, from 33% to 39%. Despite the growth rates, medical professionals acknowledge the need for improvement given the importance of exclusive breastfeeding.
Under the law of July 19, 1871, civil records registered from March 18, 1871, during the Paris Commune, were annulled and rewritten between August 1, 1871, and September 30, 1871, and in the following years. These revised records are referred to as "corrected records" (actes bâtonnés). Only the rewritten records were included in decennial tables, and their dates can differ significantly from the actual events they record. Despite being invalidated by law, the original corrected records remain in the registers and can be searched like any others. At the 12th arrondissement town hall, an accidental fire destroyed birth records from January 1, 1870, to May 25, 1871. These records were reestablished and are classified alongside those reconstructed in the official civil records reconstruction.
Sources: en.wikipedia.org
SR9009 is a synthetic research compound that acts on REV-ERB nuclear receptors. It is not approved for human use and is sold only as a research chemical. Its effects have been studied mainly in cells and rodents.
It binds REV-ERB alpha and REV-ERB beta and changes the expression of genes tied to metabolism and circadian rhythm. These changes can affect mitochondria and energy use in animal models. The exact chain from receptor binding to physiological outcome is still being mapped.
No reliable human trials show that SR9009 improves athletic performance. Some rodent studies report endurance changes, but these results are not proof of human benefit. Its use in sport is prohibited, and quality and safety data are lacking.
It is usually detected by LC-MS or HPLC-UV against a reference standard. In biological matrices, metabolite targeting can improve detection. No universal immunoassay is widely available.