Everything below concerns freeze-drying. We keep the language plain, cite what the science says, and separate well-supported claims from open questions.
Last reviewed on 2026-06-29. Where a claim depends on a specific study, the study is described rather than over-claimed.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Common synonyms | Freeze-drying, lyophilisation | Lyophilization is the American spelling; lyophilisation is British |
| Primary drying mechanism | Sublimation of ice | Occurs under vacuum below the triple point |
| Typical chamber pressure | 0.05-0.5 mbar | Range depends on product and equipment |
| Typical shelf temperature during freezing | -40 to -20 °C | Lower temperatures may be used for labile products |
| Resulting product form | Porous cake or powder | Appearance depends on formulation and cycle |
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.
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.
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, also known as freeze-drying, is a process that removes water from a material by freezing it and then reducing pressure to allow ice to sublimate directly into vapor. The method begins with a freezing step that solidifies the water content. Next, primary drying lowers the pressure below the triple point of water, enabling sublimation without passing through a liquid phase. A final secondary drying step removes bound water through desorption. This sequence produces a dry, porous cake that can be reconstituted later.
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.
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.
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.
In October 2011, a coordinated operation, Operation Linda Nchi between the Somali and Kenyan militaries and multinational forces began against the Al-Shabaab in southern Somalia. By September 2012, Somali, Kenyan, and Raskamboni forces had managed to capture Al-Shabaab's last major stronghold, the southern port of Kismayo. In July 2012, three European Union operations were launched to engage with Somalia: EUTM Somalia, EU Naval Force Somalia Operation Atalanta off the Horn of Africa, and EUCAP Nestor. As part of the official "Roadmap for the End of Transition", a political process that provided clear benchmarks leading toward the formation of permanent democratic institutions in Somalia, the Transitional Federal Government's interim mandate ended on 20 August 2012. The Federal Parliament of Somalia was concurrently inaugurated. The Federal Government of Somalia, the first permanent central government in the country since the start of the civil war, was established in August 2012 with Hassan Sheikh Mohamud elected as president. In August 2014, the Somali government-led Operation Indian Ocean was launched against insurgent-held pockets in the countryside. The next election took place in 2017 with Mohamed Abdullahi Farmajo succeeding as president. Near the end of his presidency, disagreements over the upcoming election prompted Farmajo to sign a controversial 2 year extension that was eventually overturned. In 2022, Hassan Sheikh Mohamud was re-elected for a second term.
== National variants == Similar meat and pastry recipes include the Czech klobásník, the Belgian worstenbroodje, the Dutch saucijzenbroodje, the German Münsterländer Wurstbrötchen and sausage bread in the United States. Hong Kong has developed its own style of sausage roll. Instead of having sausage meat wrapped in puff pastry like the traditional Western style, the Hong Kong style "sausage bun" (Chinese: 腸仔包) consists of a sausage wrapped inside a soft milk bread style bun.
==== Liver ==== (help wikipedia by contributing to this subsection) Glycogenosis-like phenotype of congenital hyperinsulinism due to HNF4A mutation or MODY1 (maturity-onset diabetes of the young, type 1). This phenotype of MODY1 has macrosomia and infantile-onset hyperinsulinemic hypoglycemia, physiological 3-OH butyrate, increased triglyceride serum levels, increased level of glycogen in liver and erythrocytes, increased liver transaminases, transient hepatomegaly, renal Fanconi syndrome, and later develop liver cirrhosis, decreased succinate-dependent respiration (mitochondrial dysfunction), rickets, nephrocalcinosis, chronic kidney disease, and diabetes.
The first tubeless automated insulin delivery system, Omnipod 5 uses SmartAdjust technology to actively predict glucose levels up to 60 minutes ahead and adjust insulin delivery every 5 minutes—automatically increasing, decreasing, or pausing basal insulin—towards a user‑customizable glucose target. The system integrates with several continuous glucose monitors: Dexcom G6, Dexcom G7, and Freestyle Libre 2 Plus. Omnipod 5 is FDA‑cleared for people with type 1 diabetes aged 2 years and older, and adults with type 2 diabetes aged 18+. The Omnipod 5 became available through the NHS in the UK in 2023 in limited areas, and in 2024 the NHS announced the gradual rollout of Hybrid Closed Loop systems to all type 1 diabetes patients in England over the next 5 years, including the Omnipod 5.
== Development and release == Counter-Strike: Source is a remake of the original Counter-Strike built on Valve’s Source engine and the third major installment in the Counter-Strike series. Announced on May 12, 2004 during E3 presentation as the multiplayer component of Half-Life 2, it became the first Source engine game released by Valve Software, arriving on Steam for Windows on October 7, 2004, more than a month before Half-Life 2 itself. The first public beta became available on August 11, 2004 through the Valve Cyber Café Program, followed by a wider beta release on August 18 for owners of Counter-Strike: Condition Zero and users who received Half-Life 2 vouchers bundled with select ATI Radeon video cards. The game was later included in Half-Life 2 retail bundles released on November 16, 2004. Development of Counter-Strike: Source began at Valve in January 2004, with contributions from the original Counter-Strike creators Minh Le and Jess Cliffe, as well as members of the Day of Defeat team. The main goal of the developers was to transfer Counter-Strike to the Source engine without altering the core gameplay mechanics. To achieve this, the designers took the Counter-Strike 1.1 build, stripped it down to its bare essentials, and rebuilt it piece by piece in the Source engine. They later incorporated features introduced in subsequent Counter-Strike releases, including version 1.6 and Condition Zero.
Sources: en.wikipedia.org
Insulin is an endogenous hormone, which is produced by the pancreas. The insulin protein has been highly conserved across evolutionary time, and is present in both mammals and invertebrates. The insulin/insulin-like growth factor signalling pathway (IIS) has been extensively studied in species including nematode worms (e.g.C. elegans), flies (Drosophila melanogaster) and mice (Mus musculus). Its mechanisms of action are highly similar across species. Both type 1 diabetes and type 2 diabetes are marked by a loss of pancreatic function, though to differing degrees. People who are affected with diabetes are referred to as diabetics. Many diabetics require an exogenous source of insulin to keep their blood sugar levels within a safe target range. In 1916, Nicolae C. Paulescu (1869–1931) succeeded in developing an aqueous pancreatic extract that normalized a diabetic dog. In 1921, he published 4 papers in the Society of Biology in Paris centering on the successful effects of the pancreatic extract in diabetic dogs. Research on the Role of the Pancreas in Food Assimilation by Paulescu was published in August 1921 in the Archives Internationales de Physiologie, Liège, Belgium. Initially, the only way to obtain insulin for clinical use was to extract it from the pancreas of another creature. Animal glands were obtainable as a waste product of the meatpacking industry. Insulin was derived primarily from cows (bovine) (Thorburn Brailsford Robertson (Australia); Eli Lilly and Company (USA)) and pigs (porcine) (Nordisk Insulinlaboratorium).
Anaerobic respiration is used by microorganisms, either bacteria or archaea, in which neither oxygen (aerobic respiration) nor pyruvate derivatives (fermentation) are the final electron acceptor. Rather, an inorganic acceptor such as sulfate (SO2−4), nitrate (NO−3), or sulfur (S) is used. Such organisms are found in unusual environments such as underwater caves or near hydrothermal vents at the bottom of the ocean, in digestive tracts, as well as in anoxic soils or sediment in wetland ecosystems. In July 2019, a scientific study of Kidd Mine in Canada discovered sulfur-breathing organisms which live 7900 feet (2400 meters) below the surface. These organisms are also remarkable because they consume minerals such as pyrite as their food source.
The rate of climb is good and the high speed in level flight is exceptionally good at all altitudes, from sea level to 40,000 feet. The airplane is very maneuverable with good controllability at indicated speeds up to 400 MPH [sic]. The stability about all axes is good and the rate of roll is excellent; however, the radius of turn is fairly large for a fighter. The cockpit layout is excellent, but visibility is poor on the ground and only fair in level flight. Kurt Bühligen, the third-highest scoring German fighter pilot of World War II's Western Front (with 112 confirmed victories, three against Mustangs), later stated:
The common oxidation states of rhodium are +3 and +1. Complexes with rhodium in oxidation states 0, +2, and +4 are also well characterized. The few compounds at still higher oxidation states include rhodium pentafluoride, a tetrameric complex with the true formula Rh4F20), and rhodium hexafluoride. Three rhodium oxides are Rh2O3 (a paramagnetic black powder), RhO2 (black when anhydrous but green as a hydrate), and RhO3 (only stable in the gas phase). A rhodium sulfide, Rh17S15, occurs naturally as a rare mineral miassite. Synthetic RhxSy are used as catalysts in for example H2-Br2 fuel cells.
Sources: en.wikipedia.org
Serous acinar cells are roughly pyramid shape, with the apex of the pyramid pointing towards to the center of the (roughly spherical) acinus. Inside of the cell on the side with the apex, there are specialize saliva-material containing structures called secretory granules. Compared to mucous acinar cells, their nuclei is more round, and centrally located.
A particular kind of metastable isomer is the fission isomer or shape isomer. Most actinide nuclei in their ground states are not spherical, but rather prolate spheroidal, with an axis of symmetry longer than the other axes, similar to an American football or rugby ball. This geometry can result in quantum-mechanical states where the distribution of protons and neutrons is so much further from spherical geometry that de-excitation to the nuclear ground state is strongly hindered. In general, these states either return to the ground state, or undergo spontaneous fission, with half-lives of the order of nanoseconds or microseconds, meaning it is metastable. Fission isomers may be specified with a postscript or superscript "f" rather than "m", so that a fission isomer, e.g. of plutonium-240, can be denoted as plutonium-240f or 240f94Pu.
=== Mechanism of action === The molecular mechanism of metformin is not completely understood. Multiple potential mechanisms of action have been proposed: inhibition of the mitochondrial respiratory chain (complex I), activation of AMP-activated protein kinase (AMPK), inhibition of glucagon-induced elevation of cyclic adenosine monophosphate (cAMP) with reduced activation of protein kinase A (PKA), complex IV–mediated inhibition of the GPD2 variant of mitochondrial glycerol-3-phosphate dehydrogenase (thereby reducing the contribution of glycerol to hepatic gluconeogenesis), and an effect on gut microbiota. Metformin exerts an anorexiant effect in most people, decreasing caloric intake. Metformin decreases gluconeogenesis (glucose production) in the liver. Metformin inhibits basal secretion from the pituitary gland of growth hormone, adrenocorticotropic hormone, follicle stimulating hormone, and expression of proopiomelanocortin, which in part accounts for its insulin-sensitizing effect with multiple actions on tissues including the liver, skeletal muscle, endothelium, adipose tissue, and the ovaries. The average person with type 2 diabetes has three times the normal rate of gluconeogenesis; metformin treatment reduces this by over one-third. Activation of AMPK was required for metformin's inhibitory effect on liver glucose production. AMPK is an enzyme that plays an important role in insulin signaling, whole-body energy balance, and the metabolism of glucose and fats.
The structure of the People's Armed Police is complex, and has highly varied over time. While the majority of PAP units are involved in standard policing and gendarmerie duties, the PAP has also included at different times unique specialised units. The People's Armed Police was established in 1982, taking over duties from previous units and formations that directly under the command of the People's Liberation Army. The PAP reports directly to the Central Military Commission (CMC) of the Chinese Communist Party (CCP).
A burn is an injury to skin, or other tissues, caused by heat, electricity, chemicals, friction, or ionizing radiation (such as sunburn, caused by ultraviolet radiation). Most burns are thermal burns caused by contact with heat from hot fluids (called scalding), solids, or fire. Burns occur mainly in the home or the workplace. In the home, risks are associated with domestic kitchens, including stoves, flames, and hot liquids. In the workplace, risks are associated with fire and chemical and electric burns. Alcoholism and smoking are other risk factors. Burns can also occur as a result of self-harm or violence between people (assault). Burns that affect only the superficial skin layers are known as superficial or first-degree burns. They appear red without blisters, and pain typically lasts around three days. When the injury extends into some of the underlying skin layer, it is a partial-thickness or second-degree burn. Blisters are frequently present and they are often very painful. Healing can require up to eight weeks and scarring may occur. In a full-thickness or third-degree burn, the injury extends to all layers of the skin. Often there is no pain and the burnt area is stiff. Healing typically does not occur on its own. A fourth-degree burn additionally involves injury to deeper tissues, such as muscle, tendons, or bone. The burn is often black and frequently leads to loss of the burned part. Burns are generally preventable. Treatment depends on the severity of the burn.
Sources: en.wikipedia.org
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.
Vacuum lowers the pressure below the triple point of water, allowing ice to sublimate directly into vapor. It also helps remove water vapor from the product chamber and shortens primary drying.
Many aqueous solutions and suspensions can be freeze-dried, but some formulations collapse or do not form a stable cake. The process requires careful formulation and cycle development.
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.