freeze-thaw comes up often in conversation and rarely with the context attached. Here we lay out the basics in order, then work through the practical considerations.
Last reviewed on 2026-04-17. Where a claim depends on a specific study, the study is described rather than over-claimed.
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.
SR9009 is generally described as poorly soluble in water and more soluble in organic solvents such as dimethyl sulfoxide and ethanol. Stock solutions are commonly prepared in an organic solvent before dilution into an aqueous buffer or vehicle. Precipitation can occur if the organic fraction is reduced too quickly or if the final concentration exceeds the compound's solubility limit. Sonication or gentle warming may aid dissolution in some protocols, but excessive heat can promote degradation. Container material and pH can also influence observed solubility.
SR9009 is a synthetic small molecule studied as an agonist of the nuclear receptors REV-ERBα and REV-ERBβ. These receptors help regulate circadian rhythms and metabolic gene expression. In laboratory experiments, SR9009 binds these receptors and alters transcription of genes involved in lipid handling, glucose metabolism, and mitochondrial function. It is not a naturally occurring compound and has no approved therapeutic use. Research interest stems from its ability to modify energy metabolism in cells and animal models.
In rodent studies, SR9009 has been reported to increase mitochondrial content in skeletal muscle and improve exercise endurance under some conditions. These findings led to popular descriptions such as an exercise mimetic, although that term oversimplifies the biology. Effects vary by dose, timing, tissue, and model. The compound's influence on circadian pathways means that time of administration can matter in experiments. Whether similar metabolic changes occur in humans remains largely unexplored in controlled published trials.
Pharmacokinetic data for SR9009 are limited in published literature. Some reports indicate low oral bioavailability and rapid clearance in animals, which complicates interpretation of exposure and effect. Researchers often use injected routes in preclinical work to achieve measurable systemic levels. Analytical studies rely on mass spectrometry to detect the parent compound and its metabolites. Questions about tissue distribution, active metabolites, and long-term consequences remain open. Species differences in metabolism can affect observed half-life and target engagement.
| Property | Value | Notes |
|---|---|---|
| Appearance | White to off-white powder | Visual inspection is not sufficient for identity. |
| Solubility | Soluble in DMSO and ethanol | Low solubility in water; stock solutions use organic solvent. |
| Storage | -20°C, desiccated, protected from light | Limits hydrolysis and photodegradation. |
| Analytical method | HPLC-UV/MS | Used for identity and purity assessment. |
| Synonyms | SR9009, Stenabolic | Naming varies by supplier. |
Handling practices for SR9009 focus on minimizing degradation and contamination. The solid is generally stored desiccated at or below -20 °C, protected from light and moisture. Stock solutions are often prepared in dimethyl sulfoxide or ethanol, then aliquoted to avoid repeated freeze–thaw cycles. Aqueous solubility is low, so formulations for animal studies may require cosolvents or suspending agents. Personnel should follow institutional chemical safety procedures, because toxicological data for humans are incomplete.
Regulatory status varies by country and intended use. Major drug agencies have not granted marketing authorization for SR9009 as a medicine, and it is not listed as a controlled substance in many jurisdictions. It is often sold as a research chemical, a category that may fall outside pharmaceutical manufacturing rules. Buyers should verify local laws and supplier documentation, including certificates of analysis. The lack of standardized quality controls raises concerns about identity, purity, and actual content in products marketed online.
== Etymology and history == From the Greek words baeo (little) and kystis (bladder) 1945 P. baeocystis is first collected in Eugene, Oregon. 1958 P. baeocystis is formally described and published by Singer and Smith. 1962 Psilocin is first reported in this species. 1967-68 Baeocystin and norbaeocystin are discovered and named. 1981 Testing again reveals psilocybin, psilocin, baeocystin and norbaeocystin.
Produced by Robert Eagle, directed by Patrick Fleming, made by Eagle & Eagle, with The Learning Channel. Shown on TLC in 1999 20 September Do Parents Matter?, about the psychological needs of children; the psychiatrist Stanley Greenspan; the book The Nurture Assumption by Judith Rich Harris argued that a child's associates shaped their personality, as seen most commonly in their teenage years; teenage subdivisions in the USA - the 'populars' and the 'jocks'; at university, Judith Harris had her study stopped by the famous psychology academic George Armitage Miller; Thomas J. Bouchard Jr. at the University of Minnesota and his study of separated identical twins and the effect of genes, which he estimated to be around 50%; the effect of the home was thought to account for the other 50%, but psychologists did not find anything like that; work by psychologist Carolyn Rovee-Collier; primatology and work by Frans de Waal; childhood studies by William Corsaro influenced findings; the 'normals' teenage subdivision; the 1953 Asch conformity experiments on teenagers by psychologist Solomon Asch, with five stooges in a group of six teenagers that would often exert group influence over the sixth teenager, helped findings; a similar effect was deployed in the Candid Camera series, to convince people; the 'skaters' teenage subdivision; further studies on conformity in the Stanford prison experiment of 1971 by Philip Zimbardo - the BBC made the 2002 documentary The Experiment; the 'loners' teenage subdivision.
=== Acid-base behavior === The acid dissociation constant (pKa) values of all alkanes are estimated to range from 50 to 70, depending on the extrapolation method, hence they are extremely weak acids that are practically inert to bases (see: carbon acids). They are also extremely weak bases, undergoing no observable protonation in pure sulfuric acid (H0 ~ −12), although superacids that are at least millions of times stronger have been known to protonate them to give hypercoordinate alkanium ions (see: methanium ion). Thus, a mixture of antimony pentafluoride (SbF5) and fluorosulfonic acid (HSO3F), called magic acid, can protonate alkanes.
Sources: en.wikipedia.org
=== Europe and Middle East === On March 31, 1987, Elie G. Saheb and associates acquired the Mister Donut trademark rights for the United Kingdom and opened the first Mister Donut bakery and pilot shop in Fulham, London. The trademark rights for the European markets were acquired on May 2, 1988, and for the Middle East region on October 14, 1995.
Federal agencies in the United States, such as the National Institute of Health (NIH) and National Science Foundation (NSF), have also funded research that pertains to best practices in teaching and learning of neuroscience concepts.
A similar promotion was held in September 2011, near the start of a traditional school year, encouraging the use of the game as an educational tool for science and mathematics. Valve wrote that they felt that Portal "makes physics, math, logic, spatial reasoning, probability, and problem-solving interesting, cool, and fun", a necessary feature to draw children into learning. This was tied to Digital Promise, a United States Department of Education initiative to help develop digital tools for education, which Valve is part of. Portal: Still Alive was announced for Xbox Live Arcade at the 2008 E3 convention, and was released on October 22, 2008. It features the original game, 14 new challenges, and new achievements. The additional content was based on levels from the map pack Portal: The Flash Version created by We Create Stuff and contains no additional story-related levels. According to Valve spokesman Doug Lombardi, Microsoft had previously rejected Portal on the platform due to its large size. Portal: Still Alive was well received by reviewers. 1UP.com's Andrew Hayward stated that, with the easier access and lower cost than paying for The Orange Box, Portal is now "stronger than ever". IGN editor Cam Shea ranked it fifth on his top 10 list of Xbox Live Arcade games. He stated that it was debatable whether an owner of The Orange Box should purchase this, as its added levels do not add to the plot. However, he praised the quality of the new maps included. The game ranked 7th in a later list of top Xbox Live Arcade titles compiled by IGN's staff in September 2010.
=== Water treatment === Water treatment is any process that improves the quality of water to make it more acceptable for a specific end-use. Membranes can be used to remove particulates from water by either size exclusion or charge separation. In size exclusion, the pores in the membrane are sized such that only particles smaller than the pores can pass through. The pores in the membrane are sized such that only water molecules can pass through, leaving dissolved contaminants behind.
Sources: en.wikipedia.org
Redness and swelling Induration (hardening of the skin and soft tissue) Excessive pain Systemic symptoms, including high fever > 102 °F/39 °C, fatigue, muscle pains Large amounts of smelly pus and discharge, especially at a surgical site The initial skin changes are similar to cellulitis or abscess, so diagnosis in early stages may be difficult. The redness and swelling usually blend into the surrounding normal tissues. The overlying skin may appear shiny and tense as well. Later signs more suggestive of necrotizing changes (but only present in less than half of cases) are:
In 1944, Jones became the first Black-American to become a member of the American Society of Refrigeration Engineers. 1953 Merit Award, Phyllis Wheatley Auxiliary (Phillis Wheatley Club of Cleveland, Ohio), "for outstanding achievements which serve as an inspiration to youth." In 1977, he was posthumously inducted into the Minnesota Inventors Hall of Fame. In 1991, the National Medal of Technology was awarded to Joseph A. Numero and Frederick M. Jones. President George Bush presented the awards posthumously to their widows at a ceremony in the White House Rose Garden. Jones was the first Black American to receive the award. In 1996, the Thermo King Model 'C' refrigeration unit, the world's first front-mount refrigeration unit for mobile trucks, was designated an International Mechanical Engineering Landmark by the American Society of Mechanical Engineers. Jones designed and built the prototype from junkyard salvage. The challenges were to build a structural frame and refrigerant tubing connections that would withstand the constant pounding of road vibrations. In 2007, Jones was inducted into the National Inventors Hall of Fame, which honored him as a "Visionary Veteran." In the March 2009 issue of Heavy Duty Truck magazine, editor Tom Berg dubbed Jones "The King of Cool", and wrote that his "technological breakthrough redefined the global marketplace, with cultural reverberations felt from the world's largest cities to its most isolated villages." In 2015, Jones' achievements were recognized by the creators of a Black heritage-themed playground located in Minneapolis.
Freeman's deep voice is considered to be distinctive, iconic, and recognizable which frequently makes him a preferable choice for narration in films and documentaries. The journalist Radhika Sanghani writes that his "deeply reassuring voice, with its mellifluous tones and authoritative presence, is why an entire generation still hear his trademark tones when they think of the almighty". Freeman said that his voice developed in this way while taking speech classes in college; he found that most people speak in a voice either too fast or too high and he developed a commanding voice by speaking in a lower octave and enunciating each word. According to author Miriam DeCosta-Willis, Freeman is an intuitive actor. He likes to select his roles carefully, and study the character to ensure he portrays them with depth, sensitivity, and substance. Commenting on Freeman's persona, Beverly Todd, who co-starred with him in Lean on Me (1989) and The Bucket List (2007) said: "The world knows he is such a consummate actor. He's a very sharing actor and such a nice guy. He's not the kind of actor who demands that he has all of the scenes and all the dialogues and all the emphasis is on him". Freeman has said he is interested in playing character roles and values the importance of listening carefully while filming scenes: "The big danger in acting is to wait for your line. That's what I never do. I always listen, no matter how many times we do it."
Sources: en.wikipedia.org
Liquid chromatography with mass spectrometry is a common approach. Ultraviolet detection and nuclear magnetic resonance can support identification when suitable standards are available.
The solid is generally kept cold, dry, and protected from light. Solutions are often frozen in single-use aliquots to reduce repeated freeze-thaw cycles.
It indicates a material sold for laboratory study, not for human use. The label does not guarantee pharmaceutical purity, sterility, or regulatory approval.
It is a synthetic research compound that activates REV-ERB nuclear receptors. It is not an approved drug or dietary supplement. Most information comes from cell and animal studies.