sublimation is one of those subjects where the details matter more than the headlines. This page pulls together the background, the mechanisms, and the practical points readers ask about most.
Updated 2026-03-14. Numbers and descriptions here follow the published literature rather than marketing material.
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.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Common synonym | Freeze-drying | Same dehydration operation |
| Typical vacuum | 10-100 Pa | Pressure during primary drying |
| Primary drying temperature | -40 to -10 °C | Below collapse temperature for many formulations |
| Cycle duration | 12-72 hours | Varies with load, container, and formulation |
| Key phase change | Sublimation | Solid ice to water vapor |
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.
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.
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 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.
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.
After primary drying, secondary drying removes water that remains bound to the material. This stage raises the shelf temperature while maintaining low pressure, which encourages desorption of unfrozen water. Residual moisture can be reduced to a low percentage, improving stability for many products. The process parameters, including freezing rate, shelf temperature, and chamber pressure, influence the final pore structure and reconstitution behavior. Control of these variables helps prevent collapse or meltback during drying.
=== Chuckie Mitchell === Chuck "Chuckie" Mitchell is played by James Pickens Jr. Chuckie is married to Anne Marie Mitchell and is friends with Dan and Roseanne from high school, having played football with Dan. They reignite their friendship after a chance encounter in the season 3 episode, "Bird Is the Word". After, he and Dan regularly play poker together, watch football, as well as go into business together with Bob and Roger. His being of African-American descent is partially why they're approved for a construction job at a prison. He and Anne-Marie have one child, Chuckie Jr. He remains close to Dan throughout the series and also in "The Conners."
== Role in cancer biology == The Src family of kinases is commonly associated with its role in "invasion and tumor progression, epithelial-to-mesenchymal transition, angiogenesis, and development of metastasis," all hallmarks of cancer progression. Fyn's normal function in cellular growth and proliferation has the potential to be exploited in the progression and metastasis of cancer cells. Overexpression of Fyn has been found to drive morphologic transformation in normal cells and increase "anchorage-independent growth and prominent morphologic changes." Fyn overexpression has been studied in relation to the following cancers: prostate cancer, glioblastoma multiform, squamous cell carcinoma of the head and neck, pancreatic cancer, chronic melogenic leukemia, and melanoma. This overexpression triggers a promotion of "anti-apoptotic activity of Akt" in prostate cancer, meaning that these cells have gained the ability to avoid the normal cell death pathways (a common hallmark of cancer). Additionally, in glioblastoma multiform, Src and Fyn have been found to be "effectors of oncogenic EGFR signaling" which has led to tumor invasion and cancer cell survival. Fyn's normal role in cell migration and adhesion enables it to utilize the normal cell biology of integrin and FAK for cancer growth. Normal integrin is a cell surface receptor that interacts with the extracellular matrix to send signals influencing cell shape and motility. Normal FAK is a tyrosine kinase that gets recruited to focal adhesion sites and plays a key role in directed cell movement.
== Clinical significance == Inactivity of NAGS results in N-acetylglutamate synthase deficiency, a form of hyperammonemia. In many vertebrates, N-acetylglutamate is an essential allosteric cofactor of CPS1, the enzyme that catalyzes the first step of the urea cycle. Without NAG stimulation, CPS1 cannot convert ammonia to carbamoyl phosphate, resulting in toxic ammonia accumulation. Carbamoyl glutamate has shown promise as a possible treatment for NAGS deficiency. This is suspected to be a result of the structural similarities between NAG and carbamoyl glutamate, which allows carbamoyl glutamate to act as an effective agonist for CPS1.
The Department works at the intersection of organic chemistry (chemistry of natural products, chemistry of macrocyclic compounds, chemistry of elementorganic compounds), supramolecular chemistry (solution and self-process chemistry) and molecular biology. The head of the Department is Professor Igor S. Antipin, a corresponding member of the Russian Academy of Science, Doctor of Chemistry. The Department conducts research in the following fields:
Sources: en.wikipedia.org
== History == The theory of electron capture was first discussed by Gian-Carlo Wick in a 1934 paper, and then developed by Hideki Yukawa and others. K-electron capture was first observed by Luis Alvarez, in vanadium, 48V, which he reported in 1937. Alvarez went on to study electron capture in gallium (67Ga) and other nuclides.
Rasburicase, sold under the brand name Elitek in the US and Fasturtec in the EU, is a medication that helps to clear uric acid from the blood. It is a recombinant version of urate oxidase, an enzyme that metabolizes uric acid to allantoin. Urate oxidase is known to be present in many mammals but does not naturally occur in humans. Rasburicase is produced by a genetically modified Saccharomyces cerevisiae strain. The complementary DNA (cDNA) coding for rasburicase was cloned from a strain of Aspergillus flavus. Rasburicase (Q00511) is a tetrameric protein with identical subunits. Each subunit is made up of a single 301 amino acid polypeptide chain with a molecular mass of about 34 kDa. The drug product is a sterile, white to off-white, lyophilized powder intended for intravenous administration following reconstitution with a diluent. Elitek (rasburicase) is supplied in 3 mL and 10 mL colorless, glass vials containing rasburicase at a concentration of 1.5 mg/mL after reconstitution. It is on the World Health Organization's List of Essential Medicines.
== Wood-drying kiln == A variety of wood drying kiln technologies exist today: conventional, dehumidification, solar, vacuum and radio frequency. Conventional wood dry kilns (Rasmussen, 1988) are either package-type (sideloader) or track-type (tram) construction. Most hardwood lumber kilns are sideloader kilns in which fork trucks are used to load lumber packages into the kiln. Most softwood lumber kilns are track types in which lumber packages are loaded on kiln/track cars for loading the kiln. Modern high-temperature, high-air-velocity conventional kilns can typically dry 1-inch-thick (25 mm) green lumber in 10 hours down to a moisture content of 18%. However, 1-inch-thick green Red Oak requires about 28 days to dry down to a moisture content of 8%. Heat is typically introduced via steam running through fin/tube heat exchangers controlled by on/off pneumatic valves. Less common are proportional pneumatic valves or even various electrical actuators. Humidity is removed via a system of vents, the specific layout of which are usually particular to a given manufacturer. In general, cool dry air is introduced at one end of the kiln while warm moist air is expelled at the other. Hardwood conventional kilns also require the introduction of humidity via either steam spray or cold water misting systems to keep the relative humidity inside the kiln from dropping too low during the drying cycle. Fan directions are typically reversed periodically to ensure even drying of larger kiln charges. Most softwood lumber kilns operate below 115 °C (239 °F) temperature.
Very hot objects emit UV radiation (see black-body radiation). The Sun emits ultraviolet radiation at all wavelengths, including the extreme ultraviolet where it crosses into X-rays at 10 nm. Extremely hot stars (such as O- and B-type) emit proportionally more UV radiation than the Sun. Sunlight in space at the top of Earth's atmosphere (see solar constant) is composed of about 50% infrared light, 40% visible light, and 10% ultraviolet light, for a total intensity of about 1400 W/m2 in vacuum. The atmosphere blocks about 77% of the Sun's UV, when the Sun is highest in the sky (at zenith), with absorption increasing at shorter UV wavelengths. At ground level with the sun at zenith, sunlight is 44% visible light, 3% ultraviolet, and the remainder infrared. Of the ultraviolet radiation that reaches the Earth's surface, more than 95% is the longer wavelengths of UVA, with the small remainder UVB. Almost no UVC reaches the Earth's surface. The fraction of UVA and UVB which remains in UV radiation after passing through the atmosphere is heavily dependent on cloud cover and atmospheric conditions. On "partly cloudy" days, patches of blue sky showing between clouds are also sources of (scattered) UVA and UVB, which are produced by Rayleigh scattering in the same way as the visible blue light from those parts of the sky. UVB also plays a major role in plant development, as it affects most of the plant hormones.
but that still shouldn't hurt someone taking legalized performance enhancing substances to try and absolutely RIP it out there in competition." Financial Times said the same month "A year on, with just one athlete publicly signed on to the project and no concrete plans for either a venue or a date, the project looks increasingly like a weird thought experiment, despite its high-profile backers. For D'Souza, the second Trump presidency could be what the Enhanced Games needs to get off the ground." The Times said in May 2025 "The Enhanced Games may be divisive, even dystopian to some. As far as D'Souza is concerned, they are the future — and the starting pistol is about to fire." Time listed D'Souza and Angermayer among the "Most Influential People in Health of 2025". The Economist said that the Games align with a growing human enhancement industry, aiming to improve strength, intelligence, and longevity.
Sources: en.wikipedia.org
Calcium gluconate is the calcium salt of gluconic acid and is used as a mineral supplement and medication. As a medication it is used by injection into a vein to treat low blood calcium, high blood potassium, and magnesium toxicity. Supplementation is generally only required when there is not enough calcium in the diet. Supplementation may be done to treat or prevent osteoporosis or rickets. It can also be taken by mouth but is not recommended for injection into a muscle. Side effects when injected include slow heart rate, pain at the site of injection, and low blood pressure. When taken by mouth side effects may include constipation and nausea. Blood calcium levels should be measured when used and extra care should be taken in those with a history of kidney stones. At normal doses, use is regarded as safe in pregnancy and breastfeeding. Calcium gluconate is made by mixing gluconic acid with calcium carbonate or calcium hydroxide. Calcium gluconate came into medical use in the 1920s. It is on the World Health Organization's List of Essential Medicines. Calcium gluconate is available as a generic medication. It is closely related to calcium borogluconate, which is commonly used in veterinary medicine owing to its higher solubility. It is used for intravenous administration of calcium, notably in ruminants.
=== Candidacy for mayor of Porto Alegre in 2020 === In June 2020, Melo launched his pre-candidacy to run for mayor again, bolstered by a unanimous intra-party vote. His vice-mayoral candidate was Ricardo Gomes (DEM). Other members of his coalition included Cidadania, Solidariedade, Christian Democracy, and the PRTB. Despite the PSL, the former party of former president Jair Bolsonaro, officially supporting Marchezan Júnior's reelection campaign, some deputies from the party campaigned for Melo. In the first round, he received 200,280 votes (31%), and advanced to the second round against Manuela d'Ávila, who received 187,262 (29%). Melo received support from Gustavo Paim (PP), Valter Nagelstein (PSD), João Derly (Republicanos), and from the PSDB. Melo was elected in the second round with 370,550 votes, or 54.63% of the vote.
and Gavin et al. providing updated protein interaction data for yeast organism. Chemical cross-linking is often used to "fix" protein interactions in place before trying to isolate/identify interacting proteins. Common crosslinkers for this application include the non-cleavable NHS-ester cross-linker, bissulfosuccinimidyl suberate (BS3); a cleavable version of BS3, dithiobis(sulfosuccinimidyl propionate) (DTSSP); and the imidoester cross-linker dimethyl dithiobispropionimidate (DTBP) that is popular for fixing interactions in ChIP assays. Chemical cross-linking followed by high mass MALDI mass spectrometry can be used to analyze intact protein interactions in place before trying to isolate/identify interacting proteins. This method detects interactions among non-tagged proteins and is available from CovalX. SPINE (Strepprotein interaction experiment) uses a combination of reversible crosslinking with formaldehyde and an incorporation of an affinity tag to detect interaction partners in vivo. Quantitative immunoprecipitation combined with knock-down (QUICK) relies on co-immunoprecipitation, quantitative mass spectrometry (SILAC) and RNA interference (RNAi). This method detects interactions among endogenous non-tagged proteins. Thus, it has the same high confidence as co-immunoprecipitation. However, this method also depends on the availability of suitable antibodies. Proximity ligation assay (PLA) in situ is an immunohistochemical method utilizing so called PLA probes for detection of proteins, protein interactions and modifications.
==== Analytical chemistry ==== Often there are chemical species present or necessary at one stage of sample processing that will interfere with the analysis. For example, some air monitoring is performed by drawing air through a small glass tube filled with sorbent particles that have been coated with a chemical to stabilize or derivatize the analyte of interest. The coating may be of such a concentration or characteristics that it would damage the instrumentation or interfere with the analysis. If the sample can be extracted from the sorbent using a nonpolar solvent (such as toluene or carbon disulfide), and the coating is polar (such as HBr or phosphoric acid) the dissolved coating will partition into the aqueous phase. Clearly the reverse is true as well, using polar extraction solvent and a nonpolar solvent to partition a nonpolar interferent. A small aliquot of the organic phase (or in the latter case, polar phase) can then be injected into the instrument for analysis.
In archaeology, the term in situ has been used variably to describe artifacts or features found undisturbed since deposition; however, its definition remains contested. Scholars distinguish between a broad usage, referring to materials recovered through controlled excavation, and a stricter usage applied only to those discovered in undisturbed depositional settings. Between these poles lies a continuum of depositional scenarios, from sealed habitation floors to slope or fluvial deposits, meaning that whether an object is in situ depends on site-specific formation processes and the degree to which stratigraphic—as well as spatial—relationships can be reconstructed. Recording the exact spatial coordinates, stratigraphic position, and surrounding matrix of depositional materials is necessary for understanding past human activities and historical processes. While artifacts are often removed for analysis, certain archaeological features—such as hearths, postholes, and architectural foundations—have to be thoroughly documented in place to preserve their contextual information during excavation. This documentation relies on various methods, including detailed field notes, scaled technical drawings, cartographic representation, and high-resolution photographic records. Current archaeological practice incorporates advanced digital technologies, including 3D laser scanning, photogrammetry, unmanned aerial vehicles, and Geographic Information Systems (GIS), to capture complex spatial relationships.
Sources: en.wikipedia.org
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.
Sublimation requires the solvent to remain solid so vapor leaves without passing through a liquid phase. If the product melts, the porous structure can collapse and drying becomes uneven. Maintaining frozen conditions preserves the intended physical form.
No, freeze-drying is a dehydration method, not a sterilization step. It can reduce water activity and limit microbial growth during storage, but it does not reliably kill microbes or remove endotoxins. Sterility must come from separate validated processes.
Freezing only converts liquid to solid. Lyophilization adds vacuum and controlled warming so frozen solvent sublimes, leaving a dry porous solid. The two steps are related but not interchangeable.