This is a working overview of Collapse temperature, written for readers who want more than a one-paragraph summary but less than a textbook.
Reviewed 2026-07-14. Anything still debated is marked as such rather than presented as settled.
Lyophilization removes water from a frozen material by sublimation under reduced pressure. The process begins with freezing, which converts liquid water into ice and fixes the structure of the sample. After freezing, primary drying lowers pressure so ice changes directly to vapor without passing through a liquid phase. Secondary drying then removes bound water that remains after ice sublimation. The result is a dry, porous solid that often retains its original shape.
The low pressure used during drying allows water vapor to move from the ice surface to a cold condenser. Energy supplied as heat drives sublimation but must stay below the collapse temperature of the frozen matrix. If the product becomes too warm, the frozen structure may soften or melt, reducing pore formation and slowing drying. Formulations often include bulking agents, stabilizers, or buffers to support a rigid cake. The final moisture content depends on formulation, freezing rate, and the length of secondary drying.
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 generally proceeds in three stages: freezing, primary drying, and secondary drying. During freezing, controlled cooling converts water into ice and may also crystallize or vitrify solutes. In primary drying, the pressure is lowered below the triple point, and heat is supplied so ice sublimes directly to vapor. Secondary drying removes water that remains bound to the solid matrix, yielding a low final water content. Product temperature must stay below the collapse or glass transition temperature to maintain structure. Cycle design therefore balances shelf temperature, chamber pressure, and time.
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.
| Property | Value | Notes |
|---|---|---|
| Primary phase change | Sublimation | Ice changes directly to vapor under reduced pressure |
| Typical chamber pressure | 0.01–0.5 mbar (1–50 Pa) | Below the triple point of water; product-specific |
| Typical product temperature during primary drying | −40 °C to −10 °C | Kept below collapse temperature |
| Typical residual moisture | 0.5–3% w/w | Target range varies by formulation and use |
| Common synonyms | Freeze-drying; lyophilisation | Lyophilization is the US spelling |
Lyophilization is a dehydration technique in which a product is frozen and the solvent is removed under reduced pressure. The low pressure allows ice to sublimate directly into vapor without passing through a bulk liquid phase. This differs from conventional drying, where heat drives evaporation and can damage heat-sensitive structures. The process is used for biological materials, pharmaceutical formulations, and some foods. Its main advantage is preservation of porous structure and rapid reconstitution.
Freezing is the first stage and sets the ice structure that later becomes the pore network. The formulation is cooled below its freezing point, often with a controlled ramp, and solutes concentrate as ice forms. Primary drying then lowers chamber pressure and supplies heat to sublime the ice. The product temperature must stay below its collapse or eutectic temperature to prevent structural loss. Secondary drying raises the temperature modestly to remove bound water and achieve a low residual moisture.
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.
Equipment for lyophilization includes a vacuum chamber, temperature-controlled shelves, a condenser, and a vacuum pump. A refrigeration system cools the shelves and condenser below the product's freezing point. Process monitoring often uses Pirani and capacitance manometers, thermocouples, and resistance sensors. Cycle development balances product quality with time and energy use. Some products are annealed during freezing to improve crystallization of bulking agents. Open questions remain about scaling cycles between laboratory, pilot, and production freeze-dryers.
Lyophilization, also called freeze-drying, removes water from a frozen material by sublimation under reduced pressure. The process begins with freezing, which converts free water into ice and may also produce a glassy phase. Primary drying then lowers chamber pressure so ice sublimes directly to vapor without passing through a liquid stage. Secondary drying raises the temperature modestly to remove bound water. The result is a porous, dry solid that usually reconstitutes quickly. Each stage influences pore structure, residual moisture, and stability.
The physics of lyophilization depends on phase boundaries and heat and mass transfer. During primary drying, heat supplied to the product must equal the latent heat of sublimation, while water vapor moves through the drying cake to the condenser. If shelf temperature or pressure is set too high, the ice front can exceed the collapse temperature, causing meltback or pore collapse. If conditions are too cold, drying slows and costs rise. Formulation excipients, vial geometry, and freezing rate alter these limits.
A typical cycle begins with freezing, which fixes the material into a solid and determines ice crystal size. Primary drying then raises heat under vacuum so ice sublimes, often near or below the collapse temperature of the formulation. Secondary drying removes bound water that remains after ice is gone, usually by gently warming the product. Each stage balances heat input against pressure to avoid melting or structural damage. Temperature probes and pressure sensors guide the transition between stages.
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.
== Further reading == Als, Hilton (Summer 2012). "Wallace Shawn, The Art of Theater No. 17". The Paris Review. Summer 2012 (201). Higgins, J. (2012). "The End of Room-Space: Domesticity and the Absent Audience in Wallace Shawn's the Fever". Journal of Dramatic Theory and Criticism. 26 (2): 57–74. doi:10.1353/dtc.2012.0017. S2CID 191948394. King, W. D. (1997). Writing Wrongs: The Work of Wallace Shawn. Philadelphia: Temple University Press. ISBN 1-56639-517-8. Shawn, Wallace, "The End of a Village", The New York Review of Books, vol. LXXI, no 15 (3 October 2024), pp. 16–17.
== See also == α-Pyrrolidinopropiophenone (α-PPP) 4'-Methoxy-α-pyrrolidinopropiophenone (MOPPP) 3,4-Methylenedioxy-α-pyrrolidinopropiophenone (MDPPP) 3',4'-Methylenedioxy-α-pyrrolidinobutiophenone (MDPBP)
Akt resides in the cytosol in an inactive conformation, until the cell is stimulated and it translocates to the plasma membrane. The Akt PH domain has a high affinity for second messenger PI(3,4,5)P3, binding to it preferentially over other phosphoinositides. Thus PI3K activity is essential for translocation of Akt to the membrane. Interaction with PI(3,4,5)P3 causes conformational changes and exposure of phosphorylation sites Thr308 in the kinase domain and Ser473 in the C-terminal domain. Akt is partially activated by phosphorylation of T308 by PDK1. Full activation requires phosphorylation of S473, which can be catalysed by multiple proteins, including phosphoinositide-dependent kinase 2 (PDK2), integrin-linked kinase (ILK), mechanistic target of rapamycin complex complex 2 (mTORC2) and DNA-dependent protein kinase (DNA-PK). The regulation of Ser473 phosphorylation is not fully understood but may also be influenced by autophosphorylation after Thr308 phosphorylation. After stimulation, the levels of PIP3 decrease and Akt activity is attenuated by dephosphorylation by serine/threonine phosphatases.
Sources: en.wikipedia.org
== Top scorers == Following the conclusion of the competition, Wrexham player Paul Mullin was awarded the FA Cup Golden Ball Award, commemorating him as the top scorer of the season from the extra preliminary round through to the final with eight goals.
Adrenochrome is the subject of several conspiracy theories, including QAnon and Pizzagate, in which the chemical plays a similar role to Satanic ritual abuse stories. The theories commonly say that a cabal of Satanists rape and murder children, and harvest adrenochrome from their victims' blood as a recreational drug or as an elixir of youth, as with children's blood infusions. In reality, adrenochrome has been produced by organic synthesis since at least 1952 and is synthesized for research purposes by biotechnology companies, which will then sell it to anyone; as it is not a controlled substance, medical or recreational use of the chemical is easy to access.
EF-G (elongation factor G, historically known as translocase) is a prokaryotic elongation factor involved in mRNA translation. As a GTPase, EF-G catalyzes the movement (translocation) of transfer RNA (tRNA) and messenger RNA (mRNA) through the ribosome.
Sources: en.wikipedia.org
== Description == The fool's mushroom is pure white, all the way to the gills and the stipe. This fungus, like many but not all amanitas, has a volva. The fool's mushroom's cap is 5–10 centimetres (2–4 inches) wide, and is about the same height. This mushroom's lamellae are free and white, and the volva is bag-like and large. Its annulus is white and membranous, and A. verna react yellow with 20% potassium hydroxide solution, unlike its relative Amanita phalloides var. alba while Amanita virosa gets an orange-yellow reaction. The mushroom's spores are smooth and elliptical.
Further complicating the diagnosis is the fact that many patients with Parkinson's disease will have major depressive disorder, which may be the underlying cause of catatonia. Parkinson's disease can be distinguished from catatonia by a positive response to levodopa. Catatonia, on the other hand, will show a positive response to benzodiazepines. Extrapyramidal side effects of antipsychotic medication, especially dystonia and akathisia, can be difficult to distinguish from catatonic symptoms, or may confound them in the psychiatric setting. Extrapyramidal motor disorders usually do not involve social symptoms like negativism, while individuals with catatonic excitement typically do not have the physically painful compulsion to move that is seen in akathisia. Certain stimming behaviors and stress responses in individuals with autism spectrum disorders can present similarly to catatonia. In autism spectrum disorders, chronic catatonia is distinguished by a lasting deterioration of adaptive skills from the background of pre-existing autistic symptomatology that cannot be easily explained. Acute catatonia is usually clearly distinguishable from autistic symptoms. The diagnostic entities of obsessional slowness and psychogenic parkinsonism show overlapping features with catatonia, such as motor slowness, gegenhalten (oppositional paratonia), mannerisms, and reduced or absent speech. However, psychogenic parkinsonism involves tremor which is unusual in catatonia.
In 1963, a new Yugoslav Constitution was adopted, renaming the federal state into the Socialist Federal Republic of Yugoslavia, and its federal units into socialist republics, thus introducing the name: Socialist Republic of Serbia (Serbo-Croatian Cyrillic: Социјалистичка Република Србија). In 1966, one of the most prominent Serbs in the Communist party and also vice-president of Yugoslavia (1963–1966) and founder of Yugoslav intelligence agency OZNA, Aleksandar Ranković was removed from positions due to allegations of spying on SFRY President Josip Broz Tito. After the Croatian Spring in 1971, almost whole party leadership of Serbia was removed from office, under the charge of being "liberal". Latinka Perović and Marko Nikezić were marked as leaders of this liberal movement inside League of Communists of Serbia. In 1974, new constitution was adopted, increasing the powers of provinces, and making them de facto republics. For the first time the institution of president was formed, as President of the Presidency of Socialist Republic of Serbia. Assembly was electing 15 members of the presidency and one president for a 4-year term, and later 2-year term. The new constitution practically suspended Serbia's authority over the provinces. After the new constitution was adopted, Dragoslav Marković, then President of Serbia ordered a secret study on this issue.
=== Drug development === Tew's work on redox and pharmacogenetics focused on the discovery and development of drugs. Alongside colleagues, he introduced a novel zebrafish model with a glutathione S-transferase π1 (gstp1) knockout, revealing insights into redox homeostasis, reductive stress, and responses to drugs inducing endoplasmic reticulum stress and the unfolded protein response. His research has looked into the role of GTSP in cellular redox homeostasis and its over-expression in cancer drug resistance, particularly in the context of preclinical and clinical testing of the GSTP inhibitor TLK199 (Telintra) for treating myelodysplastic syndrome. He further revealed that the absence of microsomal glutathione transferase 1 (MGST1) impacts melanin biosynthesis and melanoma growth in mice and that, in numerous species, members of the GST family are involved in early hematopoiesis, and that the lack of GSTP in dendritic cells leads to increased proliferation, ROS levels and ERα levels, suggesting a role for GSTP in controlling ERα activity and dendritic cell function. Additionally, Tew and colleagues investigated how S-glutathionylation of the protein BiP, mediated by GSTP, contributes to acquired resistance to the multiple myeloma treatment bortezomib (Btz) by impacting BiP's foldase and ATPase activities.
Sources: en.wikipedia.org
Lyophilization relies on sublimation, so water moves from solid ice to vapor without becoming liquid. The material is frozen, pressure is reduced, and controlled heat is supplied. Vapor is captured on a cold condenser, leaving a dry porous solid.
The process has three main stages: freezing, primary drying, and secondary drying. Freezing sets the ice structure, primary drying removes free ice, and secondary drying removes bound water. Each stage uses specific temperature, pressure, and time settings.
No, it is a drying method rather than a sterilization method. Removing water can limit microbial growth, but it does not reliably kill microorganisms. Sterility must come from separate steps such as filtration, heat treatment, or aseptic processing.
Yes. Lyophilization and freeze-drying are synonyms for the same vacuum-assisted sublimation process. The term lyophilization is more common in pharmaceutical and laboratory settings, while freeze-drying is widely used in food and general contexts.