A practical reference on Collapse temperature: what it is, how it behaves, what the literature reports, and where the honest uncertainties sit.
Reviewed 2025-08-05. Anything still debated is marked as such rather than presented as settled.
The physical chemistry of freezing influences whether a formulation forms an amorphous glass or a crystalline solid. Amorphous systems can collapse if product temperature rises above the glass transition temperature of the freeze concentrate. Crystalline systems may show eutectic melting, where ice and solute melt together at a fixed temperature. Formulators add bulking agents, lyoprotectants, and buffers to preserve structure and biological activity. The optimum cycle keeps product temperature below critical thresholds during primary drying while allowing efficient sublimation.
Lyophilization is a dehydration process that removes water from a frozen material by sublimation under low pressure. The material is first frozen so that water becomes ice; then the surrounding pressure is lowered below the vapor pressure of ice. Heat is applied gently so ice changes directly to vapor without passing through a bulk liquid phase. The vapor is collected on a cold condenser, leaving a dry porous matrix. This process differs from simple evaporation because the material remains frozen during the main drying stage.
In practice, lyophilization is slower and more energy intensive than simple drying. Cycle times can range from hours to several days depending on load, container, and formulation. Amorphous materials may require excipients that help preserve structure during freezing and drying. The method is widely used for biological materials, pharmaceuticals, and foods where heat drying would cause unacceptable change. Open questions remain about scaling cycles between laboratory and production equipment, and this gap affects technology transfer.
Lyophilization removes water by freezing a material and then lowering pressure so ice changes directly to vapor. The process relies on sublimation, the phase transition from solid to gas without an intermediate liquid state. Because the material remains frozen during primary drying, the structure often stays porous. This porous matrix can rehydrate quickly when water is added back. The low pressure also allows vapor to leave the solid matrix without boiling.
| Property | Value | Notes |
|---|---|---|
| Common synonyms | Freeze-drying, lyophilisation | Lyophilisation is the British spelling; the process is not simple evaporation. |
| Primary drying pressure | 0.05–0.3 mbar | Pressure must remain below the vapor pressure of ice at the product temperature. |
| Sublimation temperature | Below 0 °C | Ice changes directly to vapor while the product remains frozen. |
| Typical shelf temperature | −40 to −10 °C | Exact setting depends on formulation critical temperature and equipment. |
| Cycle duration | 12–72 hours | Time varies with fill volume, formulation, and dryer performance. |
A typical cycle begins with freezing, sometimes including an annealing step to control ice crystal size. Freezing conditions influence the pore network that later allows vapor escape. During primary drying, shelf temperature and chamber pressure are set so heat enters the product while its temperature stays below the collapse or eutectic point. Secondary drying then raises the shelf temperature to desorb bound water and lower residual moisture. Cycle design depends on formulation, fill volume, container type, and equipment capability.
The physics of lyophilization couples heat transfer, mass transfer, and phase behavior. Sublimation requires a vapor pressure difference between the ice front and the chamber, and the dried layer adds resistance to vapor flow. Amorphous formulations are characterized by a glass transition temperature of the maximally freeze-concentrated solute, often denoted Tg'. Crystalline bulking agents can provide structure, while amorphous excipients stabilize labile components. Open questions remain about spatial heterogeneity, edge effects, and how laboratory cycles scale to production.
Lyophilization is a drying process in which a solvent, usually water, is removed from a frozen material by sublimation under reduced pressure. The material is first solidified, then placed under vacuum so that ice transitions directly to vapor without a bulk liquid phase. This approach suits heat-sensitive substances that would degrade during conventional evaporation. Primary drying removes unbound ice, while secondary drying reduces water that remains adsorbed to the solid matrix. The result is a porous, lightweight solid that can be reconstituted later.
Freeze-drying is used for materials whose activity or structure depends on low temperature and low water content. Examples include certain biologics, diagnostic reagents, starter cultures, coffee, and porous inorganic precursors. The dried product forms a cake whose porosity aids rapid wetting and dissolution. Main drawbacks are high energy use, long cycle times, and sensitivity to formulation and equipment variation. Questions remain about how freezing rates and ice morphology affect batch uniformity, especially when moving from laboratory to production scale.
Lyophilization, also called freeze-drying, is a dehydration process in which a solvent, usually water, is frozen and then removed by sublimation under reduced pressure. The method preserves heat-sensitive materials that would degrade in conventional drying. Large-scale use grew during the mid-twentieth century for blood plasma and antibiotics, and it later expanded to vaccines, enzymes, foods, and advanced materials. The process produces a dry, porous solid that usually reconstitutes rapidly. It is distinct from simple evaporation because the solvent bypasses the liquid phase during primary removal.
The process relies on the phase diagram of water, where the triple point marks the conditions at which ice, liquid water, and vapor coexist. By maintaining pressure below this point, typically around 0.01 to 0.1 millibar, sublimation becomes the dominant mechanism. Formulations often include excipients such as sugars or polymers that act as lyoprotectants and bulking agents. These additives help preserve the structure of the active ingredient and prevent collapse during drying. The choice of excipient and freezing rate influences the final cake morphology and stability.
Industries use lyophilization for pharmaceuticals, biological products, and food preservation. In the pharmaceutical sector, it extends the shelf life of injectable drugs, vaccines, and proteins that are unstable in aqueous solution. Food manufacturers apply freeze-drying to coffee, fruits, and ready meals to retain flavor and texture. The process is energy-intensive and requires specialized equipment, which limits its use to high-value products. Ongoing research examines how formulation and process parameters affect the quality of the final dried product.
Lyophilization removes water from a frozen material by sublimation under reduced pressure. The process begins with freezing, which converts liquid water into ice and concentrates dissolved solids. Primary drying then lowers chamber pressure so ice changes directly into vapor without passing through a liquid phase. Secondary drying raises the shelf temperature to remove bound water that remains after ice sublimation. The result is a dry, porous structure that can be reconstituted later.
Formulation composition influences whether freeze-drying produces an intact cake or a collapsed mass. Excipients such as sugars and polymers can raise the collapse temperature and provide bulk during drying. The critical temperature for primary drying is often the collapse temperature or the glass transition temperature of the maximally concentrated phase. If the product temperature exceeds this threshold, the frozen matrix may soften and lose structure. Established practice therefore links shelf temperature and chamber pressure to the formulation's thermal properties.
==== Toxicology in aquatic environments ==== The most environmentally relevant species of these nanoparticles are silver chloride within marine ecosystems and organic thiols within terrestrial ecosystems. Once Ag0 enters the environment, it is oxidized to Ag+. Of the potential species formed in seawater, such as Ag2S and Ag2CO3, AgCl is the most thermodynamically favored due to its stability, solubility, and the abundance of Cl− in seawater. Research has shown that partially oxidized nanoparticles may be more toxic than those that are freshly prepared. It was also found that Ag dissolutes more in solution when the pH is low and bleaching has occurred. This effect, coupled with ocean acidification and increasing coral reef bleaching events, leads to a compounding effect of Ag accumulation in the global marine ecosystem. These free formed Ag+ ions can accumulate and block the regulation of Na+ and Cl− ion exchange within the gills of fish, leading to blood acidosis which is fatal if left unchecked. Additionally, fish can accumulate Ag through their diet. Phytoplankton, which form the base level of aquatic food chains, can absorb and collect silver from their surroundings. As fish eat phytoplankton, the silver accumulates within their circulatory system, which has been shown to negatively impact embryonic fish, causing spinal cord deformities and cardiac arrhythmia. The other class of organisms heavily affected by silver nanoparticles is bivalves.
Diuretic a drug or substance which has the effect of increasing the amount of urine the kidneys excrete. Swollen feet and ankles are sometimes treated with diuretics. There are several classes, which act at different points in the water resorption portion of the kidney tubule. Deoxyribonucleic acid a stable molecule which can be replicated with few errors, and which is used to store information about protein structures. It also contains mechanisms to block or unblock the transcription of that information of selected proteins at appropriate times. It was the sequence of information in a single human's DNA (that of Dr Craig Venter) which was the primary initial object of the Human Genome Project. That, and continuing work is expected to increase understanding of body functions and most likely to more effective treatments for many diseases. Its amino acid code (DNA triplet to amino acid translation) is identical across all Terrestrial life except for a very few bacteria. DNA is the chief genetic information storage structure of nearly all life on Earth. In humans and other multi-cellular organisms, the exceptions all use RNA, which is a very closely related molecule. DNA is stored chiefly in the cell nucleus of plant and animal (including human) cells. Small amounts of DNA are also kept in the mitochondria, where fuel (chiefly glucose) is processed aerobically to produce high energy chemicals (ATP) which are used throughout the cell to power energy consuming reactions. Dupuytren's contracture A condition that causes the fingers to curve inward and may also affect the palm.
About 95% of the depleted uranium produced until now is stored as uranium hexafluoride, or (D)UF6, in steel cylinders in open air storage yards close to enrichment plants. Each cylinder typically holds up to 12.7 tonnes (14.0 short tons) of UF6. In the U.S. 560,000 tonnes (620,000 short tons) of depleted UF6 had accumulated by 1993. In 2008, 686,500 tonnes (756,700 short tons) in 57,122 storage cylinders were located near Portsmouth, Ohio; Oak Ridge, Tennessee; and Paducah, Kentucky. The storage of (D)UF6 presents environmental, health, and safety risks because of its chemical instability. When UF6 is exposed to water vapor in the air, it reacts with the moisture to produce UO2F2 (uranyl fluoride), a solid, and HF (hydrogen fluoride), a gas, both of which are highly soluble and toxic. The uranyl fluoride solid acts to plug the leak, limiting further escape of depleted UF6. Release of the hydrogen fluoride gas to the atmosphere is also slowed by the plug formation. Like any other uranium compound, uranyl fluoride is radioactive, and precautions should be taken. Whether ingested, inhaled, or absorbed through the skin, it is corrosive and may harm internal organs, potentially resulting in death. Effects of exposure may be delayed. The U.S. government has been converting depleted UF6 to solid uranium oxides for use or disposal. Such disposal of the entire DUF6 inventory could cost anywhere from US$15 million to US$450 million.
Empagliflozin, sold under the brand name Jardiance ( JAR-dee-əns), among others, is an antidiabetic medication used to improve glucose control in people with type 2 diabetes and/or for patients with established heart failure with reduced ejection fraction (HFrEF). Studies have shown great benefits for heart failure (HF) outcomes and decreased hospitalisations. It is taken by mouth. Common side effects of empagliflozin include genital yeast infections and hypotension, particularly in patients with volume depletion. Other symptoms such as nausea and vomiting may occur and seem more pronounced in combination with metformin. Rare but serious adverse events, such as euglycemic diabetic ketoacidosis (DKA) which may present with hyperventilation, lethargy, or mental status changes have been reported but are infrequent in trials. Other serious but rare serious adverse events include Fournier's gangrene, a severe skin infection of the groin, and diabetic ketoacidosis that may occur even with normal blood glucose levels. Use during pregnancy or breastfeeding is not recommended. Empagliflozin is a SGLT2 inhibitor: a reversible inhibitor of the sodium glucose co-transporter-2 (SGLT-2). It reduces the kidney's glucose reabsorption and excretes the excess glucose through the urine, thus its place in the treatment of type two diabetes. It is dependent on blood glucose concentrations and the glomerular filtration rate of the kidney.
The human body produces diverse surfactants. Pulmonary surfactant is produced in the lungs in order to facilitate breathing by increasing total lung capacity, and lung compliance. In respiratory distress syndrome or RDS, surfactant replacement therapy helps patients have normal respiration by using pharmaceutical forms of the surfactants. One example of a pharmaceutical pulmonary surfactant is Survanta (beractant) or its generic form Beraksurf, produced by Abbvie and Tekzima respectively. Bile salts, a surfactant produced in the liver, play an important role in digestion. Certain caterpillars (of the moth species Spodoptera exigua, South East Asia) spit a surfactant-containing secretion at predators. This deters attacking ants, allowing the caterpillars to escape. The surfactants in the caterpillars' oral secretions reduce its surface tension. Instead of rolling off the ants' water-repellent skin like normal water, the secretion soaks the attackers. The affected ants then clean themselves, which gives the caterpillar enough time to escape.
Sources: en.wikipedia.org
=== Pain === Ketamine infusions are used for acute pain treatment in emergency departments and in the perioperative period for individuals with refractory or intractable pain. The doses are lower than those used for anesthesia, usually referred to as sub-anesthetic doses. Adjunctive to morphine or on its own, ketamine reduces morphine use, pain level, nausea, and vomiting after surgery. Ketamine is likely to be most beneficial for surgical patients when severe post-operative pain is expected, and for opioid-tolerant patients. Ketamine is especially useful in the pre-hospital setting due to its effectiveness and low risk of respiratory depression. Ketamine has similar efficacy to opioids in a hospital emergency department setting for the management of acute pain and the control of procedural pain. It may also prevent opioid-induced hyperalgesia and postanesthetic shivering. For chronic pain, ketamine is used as an intravenous analgesic, mainly if the pain is neuropathic. It has the added benefit of counteracting spinal sensitization or wind-up phenomena experienced with chronic pain. In multiple clinical trials, ketamine infusions delivered short-term pain relief in neuropathic pain diagnoses, pain after a traumatic spine injury, fibromyalgia, and complex regional pain syndrome (CRPS).
Cytokines such as IL2 and IL12, essential for T cell responses, are also regulated by vitamin D. In the domain of blood coagulation, vitamin D regulates the expression of THBD (Thrombomodulin), a key gene involved in the coagulation process. Vitamin D also affects genes involved in cell differentiation and proliferation, including p21 and p27, which regulate the cell cycle, as well as transcription factors such as c-fos and c-myc, which are involved in cell proliferation.
As with other hallucinogens, these substances are often taken for the purposes of facilitating spiritual processes, mental reflection or recreation. Some research chemicals on the market were not psychoactive, but can be used as precursors in the synthesis of other potentially psychoactive substances, for example, 2C-H, which could be used to make 2C-B and 2C-I among others. Extensive surveys of structural variations have been conducted by pharmaceutical corporations, universities and independent researchers over the last century, from which some of the presently available research chemicals derive. One particularly notable researcher is Alexander Shulgin, who presented syntheses and pharmacological explorations of hundreds of substances in the books TiHKAL and PiHKAL (co-authored with Ann Shulgin), and served as an expert witness for the defense in several court cases against manufacturers of psychoactive drugs. The majority of chemical suppliers sold research chemicals in bulk form as powder, not as pills, as selling in pill form would invalidate the claims that they were being sold for non-consumptive research. Active dosages vary widely from substance to substance, ranging from micrograms to hundreds of milligrams, but while it is critical for the end user to weigh doses with a precision scale, instead of guessing ("eyeballing"), many users did not do this and this led to many emergency room visits and several deaths, which were a prominent factor leading to the emergency scheduling of several substances and eventually Operation Web Tryp.
As of 2009, there were 5,600 registered institutions and 30,138 Cooperative societies for Khadi which employs nearly 95 lakh (9.5 million) people. Khadi and Village Industries Commission uses government provided funds to implement its programs either directly - through its 29 state offices, by directly funding Khadi and Village institutions and cooperatives, or indirectly through 33 Khadi and Village Industries Boards, which are statutory bodies formed by the state governments within India, set up for the purpose of promoting Khadi and Village Industries in their respective states. The Khadi and Village Industries Boards, in turn, fund Khadi and Village Institutions/Co-operatives/Entrepreneurs.
Sources: en.wikipedia.org
Newsom enrolled at Santa Clara University on a partial baseball scholarship, graduating in 1989 with a Bachelor of Science in political science. His application to the university was supported by letters of recommendation from former California governor Jerry Brown and a member of the school's Board of Regents. He tried out for the baseball team during his first two years but underwent elbow surgery in late 1985—later revealed as a procedure to repair a torn ulnar collateral ligament—ending his varsity aspirations. He has credited the university's Jesuit education for influencing his worldview. During his junior year, Newsom spent a semester studying abroad in Rome, Italy, an experience he called "eye-opening" in a 2019 speech.
Kripke explained that Soldier Boy was Vought's version of Wayne since he worked for them for several decades and is someone who comes from a different era, but still has the ego and ambition for which he described him as the "Homelander before Homelander." Many of the changes were applied to give Homelander a threat just as he is finally starting to take control of Vought, but Kripke wanted to ensure that it was someone that the character has never faced before with someone that has the same strength as him and could actually fight him, for which he considered Soldier Boy to be the best match. Besides introducing Soldier Boy, the season also introduces the superhero team Payback for which the character was leader. Unlike in the comics where the team served as a rival of the Seven, Payback has already disbanded by the time where the series take place; it used to be the world's premiere team of supes before the Seven was formed and is described as "the Seven before the Seven." Kripke explained that the changes were mostly done to get a deeper exploration of Vought's history by exploring the past of each member of the teams, so the writers are allowed to shed light on the show's present. The season also includes a storyline focused mostly on Kimiko Miyashiro. As the season progresses, Kimiko goes through an emotional arc for which she starts learning to express herself after spending most of her life doing what other people wanted.
== References == Black, David; Bolton, Geoffrey (2001a). Biographical Register of Members of the Parliament of Western Australia. Vol. One: 1870–1930 (Revised ed.). Parliament House: Parliament of Western Australia. ISBN 0730738140. Hansard Indexes for 1933-1936, "Legislature of Western Australia" "Special (No.19)". Western Australia Government Gazette. 24 April 1933. p. 1933:621. Also 1935:727 (29 March 1935), 1936:684 (13 May 1936), 1936:1113 (23 July 1936) and 1936:1276 (20 August 1936).
=== Sources === Kosak, Dave (April 1, 2001). "Action Half-Life: Behind the Scenes". GameSpy. Retrieved 2017-07-04. Smith, Quintin (May 29, 2008). "3 – 2 – 1… Action Half-life". Rock, Paper, Shotgun. Retrieved 2017-07-04. Meer, Alec (June 8, 2009). "Action Half-Life 2: The Sauce Of Death". Rock, Paper, Shotgun. Retrieved 2017-07-04. Smith, Quintin (March 31, 2010). "Action Half-Life: The 5 a.m." Rock, Paper, Shotgun. Retrieved 2017-07-04. Smith, Quintin (May 23, 2011). "Stop, Drop, Roll: Action Half-Life 2 V2 Out". Rock, Paper, Shotgun. Retrieved 2017-07-04. Smith, Graham (May 8, 2014). "Total Converts: Unpotting The History Of Half-Life Modding". Rock, Paper, Shotgun. Retrieved 2017-07-04.
=== Solid phase extraction === Solid phase extraction which separates long polymers like DNA from other substances found in the cells. This is similar to magnetic beads, where the solid phase is fixed and selectively binds a cellular component, allowing for its isolation.
Sources: en.wikipedia.org
The main change is sublimation, in which ice becomes water vapor without melting into liquid water. This occurs when the chamber pressure is held below the vapor pressure of ice while mild heat is supplied. The result is a dry, porous solid that retains much of its original shape.
Freezing determines ice crystal size, solute distribution, and the pore network left after drying. A slow or fast freezing rate can produce different cake structures and affect reconstitution. It also sets whether the formulation follows an amorphous or crystalline drying path.
It removes most free water during primary drying and part of the bound water during secondary drying. A small residual moisture content often remains and is specified for each product. Complete removal is generally neither practical nor desirable for stability.
Primary drying removes ice by sublimation under vacuum. Secondary drying removes water that is bound to the material, often by warming the product after most ice has left. Both stages occur below temperatures that would cause unwanted melting.