sublimation raises a handful of sensible questions. This page answers them in order, starting with the fundamentals and moving to applications.
Reviewed 2026-02-13. 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.
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.
| 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 |
The physics of freeze-drying couples heat transfer, mass transfer, and phase change. Heat supplied through the shelf must reach the sublimation front without melting the ice or degrading the product. Water vapor then travels through the already dried layer and leaves the chamber, where low pressure and cold traps keep it from returning. The dried layer acts as a resistance to vapor flow, so drying rate changes as the front recedes. Open questions remain about how pore structure and formulation heterogeneity affect drying uniformity at larger scales.
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.
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.
Jung became a full professor of medical psychology at the University of Basel in 1943 but resigned after a heart attack the next year to lead a more private life. In 1945, he began corresponding with an English Roman Catholic priest, Father Victor White, who became a close friend, regularly visiting the Jungs at the Bollingen estate. Jung became ill again in 1952. Jung continued to publish books until the end of his life, including Flying Saucers: A Modern Myth of Things Seen in the Skies (1959), which analysed the archetypal meaning and possible psychological significance of the reported observations of UFOs. In 1961, he wrote his last work, a contribution to Man and His Symbols entitled "Approaching the Unconscious" (published posthumously in 1964). Jung died on 6 June 1961 at Küsnacht after a short illness.He had been beset by circulatory diseases.
== History == In the mid-1980s, McDonald's sought to introduce menu items positioned as fresher or lighter options to compete with the Whopper from rival chain Burger King. Reporting on the chain's expansion into fresh vegetables noted that McDonald's had historically resisted placing lettuce and tomato on burgers, fearing the hot meat would wilt the ingredients and make the bun soggy. McDonald's developed a dual-compartment sandwich package that physically separated the hot and cold components. The burger was invented by Wil May, a Lufkin, Texas franchisee. It rolled out nationwide in 1985 as the McDLT. McDonald's use of polystyrene foam packaging became a frequent target of environmental criticism during the late 1980s. Activists often cited the McDLT's large container as a symbol of excessive waste. In late 1990, amid growing public and regulatory pressure, McDonald's announced it would phase out foam packaging. The chain discontinued the McDLT in January 1991, replacing it with the McLean Deluxe, a lower-fat burger that did not use the dual-compartment packaging. McDonald's revisited the "hot and cold" concept in later years with the Big N' Tasty, though it was served in standard cardboard and paper packaging. In 2025, Al Roker said he wished McDonald's would bring back the McDLT.
restrictions on the amount of exposed steel set by building codes. encasing structural steel in brick masonry or concrete to delay exposure to high temperatures. Historically, these masonry encasement methods use large amounts of heavy materials, thus greatly increasing the load to the steel frame. Newer materials and methods have been developed to resolve this issue. The following lists both older and newer methods of fireproofing steel beams (i-beams):
==== Exercise ==== A proper diet and regular exercise are foundations of diabetic care, with one review indicating that a greater amount of exercise improved outcomes. Regular exercise may improve blood sugar control, decrease body fat content, and decrease blood lipid levels.
Sources: en.wikipedia.org
In the case of children and young people, especially if they are socially disadvantaged, research suggests that it is important that healthcare providers listen to and discuss their feelings and life situation to help them engage with diabetes services and self-management. To this end, treatment programs such as the Cognitive Behavioural Therapy - Adherence and Depression program (CBT-AD) have been developed to target the psychological mechanisms underpinning adherence.
The carbonyl groups of reducing sugars react with the amino groups of amino acids in the Maillard reaction, a complex series of reactions that occurs when cooking food. Maillard reaction products (MRPs) are diverse; some are beneficial to human health, while others are toxic. However, the overall effect of the Maillard reaction is to decrease the nutritional value of food. One example of a toxic product of the Maillard reaction is acrylamide, a neurotoxin and possible carcinogen that is formed from free asparagine and reducing sugars when cooking starchy foods at high temperatures (above 120 °C). However, evidence from epidemiological studies suggest that dietary acrylamide is unlikely to raise the risk of people developing cancer.
The In-N-Out menu consists of three burger varieties: hamburger, cheeseburger, and "Double-Double" (two hamburger patties and two slices of cheese). French fries and fountain drinks are available, as well as three flavors of milkshakes. The hamburgers come with lettuce, tomato, with or without onions (the customer is asked upon ordering, and may have them fresh or grilled), and a sauce, which is called "spread" (a Thousand Island dressing variant). There are additional named items not on the menu, but available at every In-N-Out. These variations reside on the chain's "secret menu", though the menu is accessible on the company's website. These variations include 3×3 (which has three patties and three slices of cheese), 4×4 (four patties and four slices of cheese), Neapolitan shakes, grilled cheese sandwich (consists of the same ingredients as the burgers except the meat, plus two slices of melted cheese), Protein Style (wrap with lettuce; consists of the same ingredients as the burgers except buns), and Animal Style (cooked in a thin layer of mustard, adding condiments including pickles, grilled onions, and extra spread). Animal Style fries come with two slices of melted cheese, spread, and grilled onions on top. Whole or sliced chili peppers are also available by request. Both Protein and Animal Style are house specialties that the company has trademarked because of their association with the chain.
Laminin G domain: all laminin alpha chains (LAMA1, LAMA2, LAMA3, LAMA4, LAMA5), cadherin EGF LAG seven-pass G-type receptors (CELSR1, CELSR2, CELSR3), contactin-associated proteins (CNTNAP1, CNTNAP2, CNTNAP3, CNTNAP3B, CNTNAP4, CNTNAP5), some collagens (COL5A1, COL5A3, COL9A1, COL11A1, COL11A2, COL12A1, COL14A1, COL15A1, COL16A1, COL18A1, COL19A1, COL20A1, COL21A1, COL22A1, COL24A1, COL27A1), crumbs homologs 1 and 2 (CRB1, CRB2), fat homologs (FAT1, FAT2, FAT3, FAT4), NEL-like proteins (NELL1, NELL2), neurexins (NRXN1, NRXN2, NRXN3), slit homologs (SLIT1, SLIT2, SLIT3), thrombospondins (THBS1, THBS2, THBS3, THBS4, TSPEAR), agrin (AGRIN), chondroitin sulfate proteoglycan 4 (CSPG4), eyes shut homolog (EYS), growth arrest-specific protein 6 (GAS6), perlecan (HSPG2), pikachurin (EGFLAM), protein S (PROS1), sex hormone-binding globulin (SHBG) and usherin (USH2A) Laminin N-terminal (domain VI): most laminin chains (LAMA1, LAMA2, LAMA3, LAMA5, LAMB1, LAMB2, LAMB3, LAMB4, LAMC1, LAMC3), most netrins (NTN1, NTN3, NTN4, NTNG1, NTNG2), and usherin (USH2A)
nuclear magnetic resonance spectroscopy A technique that exploits the magnetic properties of certain atomic nuclei, useful for identifying unknown compounds. Nuclear magnetic resonance is often abbreviated NMR.
Sources: en.wikipedia.org
=== Urinary tract infections === Urinary tract infections (UTIs) are often due to E. coli entering the urethra and colonizing. The host's immune system will release protamines and other antimicrobials to combat the infection, but OmpT easily degrades the cationic protamine peptides, thus enhancing the risk of infection. There is a genetic link between OmpT and other UTI-mediating factors (such as kpsMT, cnf1, prf, and sfa), but the functional link between these proteins is not well defined.
Events in 1958 – notably a riot during Vice President Nixon's visit to Caracas, Venezuela, in May 1958 – resulted in a reversal of the U.S. position in August 1958. With U.S. support, in April 1959 the Organization of American States created the Inter-American Development Bank, most of whose capital was contributed by the borrowing countries. To further engage other wealthy countries in development assistance, the United States supported the creation of the Aid India Consortium in August 1958. This was the first of several informal groupings of donors focussing on particular countries. The United States also encouraged Western Europe and Japan to increase their development assistance by building on the European Marshall Plan organization, the Organization of European Economic Cooperation (OEEC). The OEEC had been created in 1948 by recipients of Marshall Plan aid, at the request of the United States government, to decide on allocation of that aid within Europe, and by the late 1950s it had fulfilled its original mandate. In January 1960, Eisenhower and Under Secretary of State C. Douglas Dillon got agreement from OEEC members to create a Development Assistance Group composed of the OEEC members who were the main sources of development assistance, along with non-members who were major donors – the U.S., Canada, and Japan. In 1961, the OEEC itself was restructured to become the Organisation for Economic Co-operation and Development, which established a Development Assistance Committee (DAC) as a restructured DAG that was brought under the OECD.
== Industry and Research Community == Commercial products and companies based on aptamers include the drug Macugen (pegaptanib) and the clinical diagnostic company SomaLogic. The International Society on Aptamers (INSOAP), a professional society for the aptamer research community, publishes a journal devoted to the topic, Aptamers. Apta-index is a current database cataloging and simplifying the ordering process for over 700 aptamers.
==== Krukenberg tumor ==== A Krukenberg tumor is a quickly developing malignant tumor found in one or both ovaries. In most cases, the tumor primarily originates from tissues in the stomach, pancreas, gallbladder, colon, or breast. It colonized the ovary by spreading through the peritoneal cavity. These tumors cause virilization. Increased androgen production due to elevations in human chorionic gonadotropin is hypothesized as the main cause of hyperandrogenism in women with Krukenberg tumors.
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.
Simple drying usually removes water by evaporation from a liquid or solid, often with heat. Lyophilization first freezes the material and then removes ice by sublimation under vacuum. This avoids prolonged exposure to liquid water and high temperatures.