Collapse temperature 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.
Updated 2026-07-12. Numbers and descriptions here follow the published literature rather than marketing material.
Secondary drying removes bound water that remains after ice sublimation. Shelf temperature is raised gradually while pressure remains low, reducing water content to a target range. Over-drying can cause brittleness or electrostatic issues, while under-drying affects stability. The endpoint is often judged by pressure rise tests, temperature measurements, or water content analysis. Scale-up depends on matching heat and mass transfer across equipment sizes. Small changes in shelf temperature or pressure can alter cycle length substantially.
Lyophilization, or freeze-drying, removes water from a material by freezing it and then lowering pressure so ice changes directly to vapor. The process relies on sublimation, the phase transition from solid to gas without an intervening liquid state. It is used for heat-sensitive materials that would degrade in conventional drying. The three stages are freezing, primary drying, and secondary drying, each with distinct temperature and pressure requirements. In practice, cycle design balances these variables.
Freezing determines ice crystal structure and pore size, which affect drying speed and product uniformity. Rapid freezing creates small crystals, while slow freezing creates larger crystals and often faster sublimation. During primary drying, chamber pressure is held below the vapor pressure of ice, and shelf temperature supplies heat for sublimation. The ice front recedes, leaving a porous matrix. Thermal limits such as collapse and eutectic temperatures set safe boundaries for formulation. These limits vary with solute composition and concentration.
A formulation often contains excipients that protect the active ingredient during freezing and drying. Bulking agents provide structure, while lyoprotectants stabilize sensitive molecules. The freezing step can produce ice crystals whose size and distribution affect the drying rate, and cycle design includes freezing, annealing, and drying phases. If the product temperature rises above a critical value, the cake may collapse or lose its porous structure. Successful lyophilization therefore depends on the interaction between formulation, equipment, and cycle design.
Lyophilization is a dehydration process that removes water from a frozen material by sublimation under low pressure. The material is first frozen to convert liquid water into ice. Next, the pressure is reduced below the triple point of water so that ice changes directly into vapor without passing through a liquid phase. This step is called primary drying. The result is a porous solid or cake that retains the original shape of the frozen solution.
| Property | Value | Notes |
|---|---|---|
| Process name | Lyophilization or freeze-drying | Both terms appear in technical standards and literature. |
| Phase transition | Sublimation | Solid ice becomes vapor without a liquid step. |
| Typical chamber pressure | 0.05-0.5 mbar | Range depends on product temperature and equipment. |
| Typical product temperature | -40 °C to -10 °C | Measured during primary drying; formulation sets limits. |
| Water content after drying | 0.5-3% w/w | Target varies by material and stability needs. |
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 distinct from simple evaporation and from spray drying. Evaporation removes water at temperatures above freezing, while spray drying rapidly dries droplets in a heated gas stream. Lyophilization avoids high temperatures, which can be useful for heat-sensitive materials such as proteins, vaccines, and some foods. The porous cake produced by sublimation dissolves or rehydrates more quickly than a dense dried mass. Not all materials tolerate freezing or the pH shifts that can occur as solutes concentrate during ice formation.
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.
Immediately after the split, William Reid went solo as Lazycame—having already released a solo EP in April 1998—and Jim Reid founded Freeheat along with Lurie and ex-Gun Club bassist Romi Mori and Earl Brutus drummer Nick Sanderson, although neither act received much attention or found any success. In October 2005, it was announced that the Reids were reunited; Jim Reid's track "Song for a Secret" a duet with his wife Julie Barber, was released as a single, paired up with Sister Vanilla's "Can't Stop The Rock", which was written and produced by William and the brothers' younger sibling, Linda. The single was released by Transistor Records on 17 October. Jim promoted his side of the single with a very rare solo gig at London's Sonic Cathedral club on John Peel Day, Thursday 13 October 2005. He finished the appearance with a performance of the early Mary Chain classic "Never Understand". Jim also performed new material at low-key gigs with a new band comprising Phil King on guitar, Loz Colbert (Ride) on drums and bassist Mark Crozer (International Jetsetters). In 2006 five albums were reissued through Rhino Records: Psychocandy, Darklands, Automatic, Honey's Dead and Stoned & Dethroned on 11 July 2006. Each album was released with a DVD containing three promo videos from that particular album.
Lindow Man, also known as Lindow II and (in jest) as Pete Marsh, is the preserved bog body of a man discovered in a peat bog at Lindow Moss near Wilmslow in Cheshire, North West England. The remains were found on 1 August 1984 by commercial peat cutters. Lindow Man is not the only bog body to have been found in the moss; Lindow Woman was discovered the year before, and other body parts have also been recovered. The find was described as "one of the most significant archaeological discoveries of the 1980s" and caused a media sensation. It helped invigorate the study of British bog bodies, which had previously been neglected. Dating the body has proven problematic, but it is thought that he was deposited into Lindow Moss, face down, sometime between 2 BC and 119 AD, in either the Iron Age or Romano-British period. At the time of death, Lindow Man was a healthy male in his mid-20s, and may have been of high social status as his body shows little evidence of having done heavy or rough physical labour during his lifetime. There has been debate over the reason for his death; his death was violent and perhaps ritualistic. The recovered body has been preserved by freeze-drying and is on permanent display at the British Museum, although it occasionally travels to other venues such as the Manchester Museum.
Haldane's "Primordial soup" ideas were emerging, which hypothesized that a chemically-reducing atmosphere on early Earth would have been conducive to organic synthesis in the presence of sunlight or lightning, gradually concentrating the ocean with random organic molecules until life emerged. In this way, frameworks for the origin of life were coming together, but at the mid-20th century, hypotheses lacked direct experimental evidence.
Burial, also known as interment or inhumation, is a method of final disposition whereby a dead body is placed into the ground or in a structure such as a mausoleum, sometimes with objects. This is usually accomplished by excavating a pit or trench, placing the deceased and objects in it, and covering it over. A funeral is a ceremony that accompanies the final disposition. Evidence suggests that some archaic and early modern humans buried their dead. Burial is often seen as indicating respect for the dead. It has been used to prevent the odor of decay, to give family members closure and prevent them from witnessing the decomposition of their loved ones, and in many cultures it has been seen as a necessary step for the deceased to enter the afterlife or to give back to the cycle of life. Methods of burial may be heavily ritualized and can include natural burial (sometimes called "green burial"); embalming or mummification; and the use of containers for the dead, such as shrouds, coffins, grave liners, and burial vaults, all of which can slow decomposition of the body. Sometimes objects or grave goods are buried with the body, which may be dressed in fancy or ceremonial garb. Depending on the culture, the manner in which the body is positioned may have great significance. The location of the burial may be determined by taking into account concerns surrounding health and sanitation, religious concerns, and cultural practices.
This may also be considered in patients for whom lifestyle therapy has failed, or is not sustainable, who are at high-risk for developing type 2 diabetes, or who prefer to take a medication. Metformin and acarbose help prevent the development of prediabetes, and also have a good safety profile. Evidence also supports thiazolidinediones but there are safety concerns, and data on newer agents such as GLP-1 receptor agonists, DPP4 inhibitors or meglitinides are lacking.
Sources: en.wikipedia.org
In molecular biology, the copper type II ascorbate-dependent monooxygenases are a class of enzymes that require copper as a cofactor and which use ascorbate as an electron donor. This family contains two related enzymes, dopamine beta-monooxygenase EC 1.14.17.1 and peptidylglycine alpha-amidating monooxygenase EC 1.14.17.3. There are a few regions of sequence similarities between these two enzymes, two of these regions contain clusters of conserved histidine residues which are most probably involved in binding copper.
In the second phase of the program, the Nigerian government developed the Nigerian Agricultural Payment Initiative (NAPI), which distributed PIN-enabled ID cards that hold subsidy information and provide access to loans and grants. Other e-wallet/e-voucher systems for agricultural subsidies exist or have been piloted in Colombia, Rwanda, Zambia, Mali, Guinea, and Niger. Besides reducing subsidy costs, governments can harness digital technology to save time. When Estonia implemented their e-ID and X-Road system, time spent applying for agricultural subsidies decreased from 300 minutes to 45 minutes per person. Typically, a system of digital agriculture technologies, rather than a single tool, is used to solve multifaceted problems. For example, e-commerce solves two efficiency issues: difficulty matching buyers and sellers, especially in rural areas, and the high transaction costs associated with in-person, cash-based trade.
== Discovery == Notch was discovered in a mutant Drosophila in March 1913 in the lab of Thomas Hunt Morgan. This mutant emerged after several generations of crossing out and back-crossing beaded winged flies with wild type flies and was first characterized by John S. Dexter. The most frequently observed phenotype in Notch mutant flies is the appearance of a concave serration at the most distal end of the wings, for which the gene is named, accompanied by the absence of marginal bristles. This mutant was found to be a sex-linked dominant on the X chromosome that could only be observed in heterozygous females as it was lethal in males and homozygous females. The first Notch allele was established in 1917 by Charles William Metz and Calvin Bridges. In the late 1930s, studies of fly embryogenesis done by Donald F. Poulson provided the first indication of Notch's role in development. Notch mutant males exhibited a lack of the inner germ layers, the endoderm and mesoderm, that resulted in failure to undergo later morphogenesis embryonic lethality. Later studies in early Drosophila neurogenesis provided some of the first indications of Notch's roll in cell-cell signaling, as the nervous system in Notch mutants was developed by sacrificing hypodermal cells. Starting in the 1980s researchers began to gain further insights into Notch function through genetic and molecular experiments.
=== Insulin structure === Insulin was one of Hodgkin's most extraordinary research projects. It began in 1934 when she was offered a small sample of crystalline insulin by Robert Robinson. The hormone captured her imagination because of the intricate and wide-ranging effect it has in the body. However, at this stage X-ray crystallography had not been developed far enough to cope with the complexity of the insulin molecule. She and others spent many years improving the technique. It took 35 years after taking her first photograph of an insulin crystal for X-ray crystallography and computing techniques to be able to tackle larger and more complex molecules like insulin. Hodgkin's dream of unlocking the structure of insulin was put on hold until 1969 when she was finally able to work with her team of young, international scientists to uncover the structure for the first time. Hodgkin's work with insulin was instrumental in paving the way for insulin to be mass-produced and used on a large scale for treatment of both type one and type two diabetes. She went on to cooperate with other laboratories active in insulin research, giving advice, and traveling the world giving talks about insulin and its importance for the future of diabetes. Solving the structure of insulin had two important implications for the treatment of diabetes, both making mass production of insulin possible and allowing scientists to alter the structure of insulin to create even better drug options for patients going forward.
Sources: en.wikipedia.org
Both photos became symbolic of the suffering of victims of the Bhopal disaster, and Bartholomew went on to win the 1985 World Press Photo of the Year. Within a few days, trees in the vicinity became barren, and bloated animal carcasses had to be disposed of. 170,000 people were treated at hospitals and temporary dispensaries, and 2,000 buffalo, goats, and other animals were collected and buried. Supplies, including food, became scarce owing to suppliers' safety fears. Fishing was prohibited, causing further supply shortages. Lacking any safe alternative, on 16 December, tanks 611 and 619 were emptied of the remaining MIC by reactivating the plant and continuing the manufacture of pesticide. Despite safety precautions such as having water-carrying helicopters continually overflying the plant, this led to a second mass evacuation from Bhopal. The Government of India passed the "Bhopal Gas Leak Disaster Act" that gave the government rights to represent all victims, whether or not in India. Complaints of lack of information or misinformation were widespread. An Indian government spokesman said, "Carbide is more interested in getting information from us than in helping our relief work". Formal statements were issued that air, water, vegetation, and foodstuffs were safe, but people were warned not to consume fish. The number of children exposed to the gases was at least 200,000. Within weeks, the State Government established a number of hospitals, clinics, and mobile units in the gas-affected area to treat the victims. S. Ravi Rajan (Prof. Environmental Studies, U.C.
== Applications == The highest selling transdermal patch in the United States is the nicotine patch, which releases nicotine in controlled doses to help with cessation of tobacco smoking. The first commercially available vapour patch to reduce smoking was approved in Europe in 2007. Two opioid medications used to provide round-the-clock relief for severe pain are often prescribed in patch form, fentanyl CII (marketed as Duragesic) and buprenorphine CIII (marketed as BuTrans). Hormonal patches: Estrogen patches are sometimes prescribed to treat menopausal symptoms (as well as post-menopausal osteoporosis) and to transgender women as a type of hormone replacement therapy. Contraceptive patches (marketed as Ortho Evra or Evra) and Testosterone CIII patches for both men (Androderm) and women (Intrinsa). Nitroglycerin patches are sometimes prescribed for the treatment of angina in lieu of sublingual pills. Transdermal scopolamine is commonly used as a treatment for motion sickness. The anti-hypertensive drug clonidine is available in transdermal patch form. Emsam, a transdermal form of the MAOI selegiline, became the first transdermal delivery agent for an antidepressant approved for use in the U.S. in March 2006. Daytrana, the first methylphenidate transdermal delivery system for the treatment of attention deficit hyperactivity disorder (ADHD), was approved by the FDA in April 2006. Secuado, a transdermal form of the atypical antipsychotic asenapine, was approved by the FDA in October 2019.
An indicative cost structure for a fine chemical company is shown in Table 10. Nowadays, a full 7-day/week operation, consisting of four or five shift teams, each working 8h per day, has become the standard. In terms of production costs, this is the most advantageous scheme. Higher salaries for night work are more than offset by better fixed cost absorption. As part of the budgeting process, standard costs for a production campaign of a particular fine chemical are determined on the basis of past experience. The actual results of the campaign are then compared with the standard. The capability of a fine chemical company to make dependable manufacturing cost forecasts is a distinct competitive advantage.
Elastic fibers (or yellow fibers) are an essential component of the extracellular matrix composed of bundles of proteins (elastin) which are produced by a number of different cell types including fibroblasts, endothelial, smooth muscle, and airway epithelial cells. These fibers are able to stretch many times their length, and snap back to their original length when relaxed without loss of energy. Elastic fibers include elastin, elaunin and oxytalan. Elastic fibers are formed via elastogenesis, a highly complex process involving several key proteins including fibulin-4, fibulin-5, latent transforming growth factor β binding protein 4, and microfibril associated protein 4. In this process tropoelastin, the soluble monomeric precursor to elastic fibers is produced by elastogenic cells and chaperoned to the cell surface. Following excretion from the cell, tropoelastin self associates into ~200 nm particles by coacervation, an entropically driven process involving interactions between tropoelastin's hydrophobic domains, which is mediated by glycosaminoglycans, heparan, and other molecules. These particles then fuse to give rise to 1-2 micron spherules which continue to grow as they move down from the cells surface before being deposited onto fibrillin microfibrillar scaffolds. Following deposition onto microfibrils tropoelastin is insolubilized via extensive crosslinking by members of the lysyl oxidase and lysyl oxidase like family of copper-dependent amine oxidases into amorphous elastin, a highly resilient, insoluble polymer that is metabolically stable over a human lifespan.
Samoyeds can compete in dog agility trials, carting, obedience, showmanship, flyball, tracking, mushing and herding events. Herding instincts and trainability can be measured at non-competitive herding tests. Samoyeds exhibiting basic herding instincts can be trained to compete in herding trials.
Sources: en.wikipedia.org
Conventional drying uses heat to evaporate liquid water, often at temperatures that can degrade sensitive materials. Lyophilization freezes the material first and then removes water by sublimation under vacuum. This avoids prolonged exposure to liquid water and high heat.
Lowering pressure reduces the boiling point of water and allows ice to sublimate at temperatures below freezing. Vacuum also limits convective heat transfer, so heat is usually supplied by shelves or radiation. The pressure must stay below the vapor pressure of ice at the product temperature.
The cycle typically includes freezing, primary drying, and secondary drying. Freezing solidifies water and sets the pore structure; primary drying removes bulk ice; secondary drying removes bound water. Some cycles add annealing or pre-freezing steps.
Lyophilization removes water by sublimation from a frozen material, while evaporation changes liquid water into vapor. The low-pressure freezing step avoids the liquid phase and can preserve heat-sensitive structures.