This is a working overview of Sublimation, written for readers who want more than a one-paragraph summary but less than a textbook.
This page was last updated on 2026-08-01 and is reviewed periodically as new material appears.
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.
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.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Common names | Lyophilization; freeze-drying | Terms used interchangeably. |
| Phase change | Sublimation | Ice converts directly to vapor under vacuum. |
| Typical chamber pressure | 0.01–1 mbar | Below the triple point of water. |
| Primary drying product temperature | −40 to −10 °C | Kept below collapse or glass transition temperature. |
| Water content after drying | 0.5–3% w/w | Varies with formulation and cycle. |
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.
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.
The neuromedin U receptors are two G-protein coupled receptors which bind the neuropeptide hormones neuromedin U and neuromedin S. There are two subtypes of the neuromedin U receptor, each encoded by a separate gene (NMUR1, NMUR2).
Governor William Robinson shared the same view with the former, insisted that a Medical Department with a Principal Civil Medical Officer directly under the Government should replace the Sanitary Board. With regard of the reconstitution of the Sanitary Board, Governor William Robinson conducted a plebiscite in June 1896. Besides the reconstitution of the Sanitary Board issues, in 1894 there was a group of petitioners supported by the Unofficial Members of the Legislative Council Paul Chater and Ho Kai with 363 signatures asked for a further representations in the Colonial Government. They demanded:
CendR (C-end Rule) is a position-dependent protein motif that regulates cellular uptake and vascular permeability through interaction with neuropilin-1. The CendR motif has a consensus (R/K)XX(R/K) and it is able to interact with its receptor only when the second basic residue is exposed at the C-terminus.
The thyroid hormones are created from thyroglobulin. This is a protein within the colloid in the follicular lumen that is originally created within the rough endoplasmic reticulum of follicular cells and then transported into the follicular lumen. Thyroglobulin contains 123 units of tyrosine, which reacts with iodine within the follicular lumen. Iodine is essential for the production of the thyroid hormones. Iodine (I0) travels in the blood as iodide (I−), which is taken up into the follicular cells by a sodium-iodide symporter. This is an ion channel on the cell membrane which in the same action transports two sodium ions and an iodide ion into the cell. Iodide then travels from within the cell into the lumen, through the action of pendrin, an iodide-chloride antiporter. In the follicular lumen, the iodide is then oxidized to iodine. This makes it more reactive, and the iodine is attached to the active tyrosine units in thyroglobulin by the enzyme thyroid peroxidase. This forms the precursors of thyroid hormones monoiodotyrosine (MIT), and diiodotyrosine (DIT). When the follicular cells are stimulated by thyroid-stimulating hormone, the follicular cells reabsorb thyroglobulin from the follicular lumen. The iodinated tyrosines are cleaved, forming the thyroid hormones T4, T3, DIT, MIT, and traces of reverse triiodothyronine. T3 and T4 are released into the blood. The hormones secreted from the gland are about 80–90% T4 and about 10–20% T3. Deiodinase enzymes in peripheral tissues remove the iodine from MIT and DIT and convert T4 to T3 and RT3.
Sources: en.wikipedia.org
==== Alternative-composition breast prosthesis ==== The third category of prosthetic breast includes alternative-composition breast prostheses that featured fillers such as soy oil, polypropylene string, ox cartilage, Terylene wool, ground rubber, silastic rubber, and Teflon-silicone, which are substances harmful to the woman's body.
creatine + phosphate Thus, the two substrates of this enzyme are N-phosphocreatine and H2O, whereas its two products are creatine and phosphate. This enzyme belongs to the family of hydrolases, specifically those acting on phosphorus-nitrogen bonds. The systematic name of this enzyme class is phosphamide hydrolase. This enzyme is also called creatine phosphatase.
Chromatography – to measure the quality of product or reactants Density (oil) – for custody metering of liquids Dewpoint (water dewpoint and hydrocarbon dewpoint) to check the efficiency of dehydration or dewpoint control plant Electrical conductivity – to measure the effectiveness of potable water reverse osmosis plant Oil-in-water – prior to discharge of water into the environment pH of reactants and products Sulphur content – to check the efficiency of gas sweetening plant Most instruments function continuously and provide a log of data and trends. Some analyser instruments are configured to alarm (AAH) if a measurement reaches a critical level.
==== Charge rate ==== The company's planned 2025 batteries were projected to have a peak charging rate of 350kW and a service life of 1000 fast-charging cycles. StoreDot battery cells require liquid cooling within each cell during fast charging. StoreDot announced their 2025 batteries would charge at a rate that adds 100 miles in 5 minutes for a vehicle that uses 14kWh per 100 kilometers, which corresponds to a charging rate of 270kW. StoreDot had been developing faster-charging cells that charge a 75kWh battery 70% in 10 minutes (from 10% to 80%) which corresponds to a charging rate of 315kW, which it aimed to deliver in 2026. StoreDot stated in 2026 it needs two more years of development in order to commercialize its product.
10 September – MPs vote 348–228 to restrict winter fuel payments to pensioners receiving Pension Credit. 2024 Conservative Party leadership election: Mel Stride is eliminated from the leadership contest in the second round of voting. 11 September – The Scottish Government loses a non-binding vote calling for the rollout of free school meals to all primary school pupils, with MSPs voting 64–2 for the motion. First Minister of Wales Eluned Morgan carries out her first cabinet reshuffle, which includes appointing Jeremy Miles as Health Minister and Mark Drakeford as finance minister. 12 September – 2024 Alliance Party deputy leadership election: Alliance's party executive meeting will set the timescale for election of a new deputy leader. 13 September – Starmer visits the White House to hold talks with US president Joe Biden. The Green Party of England and Wales is ordered to pay £90,000 in compensation after former deputy leader Shahrar Ali won a discrimination case against them. 14 September – Former Conservative immigration minister Timothy Kirkhope says he "regrets" his government's "Stop the Boats" rhetoric, which he believes helped to inflame the 2024 United Kingdom riots. UEFA warns the UK government that Britain could be prevented from hosting Euro 2028 over plans for a football regulator (outlined in the Football Governance Bill) because of concerns about "government interference" in the sport.
Sources: en.wikipedia.org
=== Marine toxicity === Plutonium is known to enter the marine environment by dumping of waste or accidental leakage from nuclear plants. Though the highest concentrations of plutonium in marine environments are found in sediments, the complex biogeochemical cycle of plutonium means it is also found in all other compartments. For example, various zooplankton species that aid in the nutrient cycle will consume the element on a daily basis. The complete excretion of ingested plutonium by zooplankton makes their defecation an extremely important mechanism in the scavenging of plutonium from surface waters. However, those zooplankton that succumb to predation by larger organisms may become a transmission vehicle of plutonium to fish. In addition to consumption, fish can also be exposed to plutonium by their distribution around the globe. One study investigated the effects of transuranium elements (plutonium-238, plutonium-239, plutonium-240) on various fish living in the Chernobyl Exclusion Zone (CEZ). Results showed that a proportion of female perch in the CEZ displayed either a failure or delay in maturation of the gonads. Similar studies found large accumulations of plutonium in the respiratory and digestive organs of cod, flounder and herring. Plutonium toxicity is just as detrimental to larvae of fish in nuclear waste areas. Undeveloped eggs have a higher risk than developed adult fish exposed to the element in these waste areas.
== Significance == AKH has become an important area of study, particularly in insect crop pests and insects that act as intermediate or vector hosts for parasites that can affect humans or animals . In experiments where locusts were injected with AKH and lipopolysaccharide (LPS–an immune elicitor found in the cell walls of bacteria) a stronger immune response was observed than in locusts that only received an LPS injection. The spread of malaria by the female mosquito, Anopheles gambiae, is partly dependent on the adipokinetic hormone, Anoga-HrTH (pGlu-Leu-Thr-Phe-Thr-Pro-Ala-Trp-NH2). No crystal structure of this important neuropeptide is available. The NMR restrained molecular dynamic was used to investigate its conformational space in aqueous solution and when bound to a membrane surface. The results showed that Anoga-HrTH has an almost cyclic conformation that is stabilized by a hydrogen bond between the C-terminus and Thr3. When the agonist docks to its receptor, this H-bond is broken and the molecule adopts a more extended structure. Preliminary AKHR docking calculations give the free energy of binding to be −47.30 kJ/mol. Information about the 3D structure and binding mode of Anoga-HrTH to its receptor are vital for the design of suitable mimetics which can act as insecticides.
Negros is the second largest island in the Visayas (after Samar) and the fourth largest of the Philippines, with a total land area of 13,309.6 square kilometres (5,138.9 sq mi), similar to Flores or Jamaica. It is located between the islands of Panay and Guimaras to the west and Cebu to the east, with Siquijor located on the toe of the island and the islands of Bantayan to the north. Politically and linguistically, Negros is divided into two provinces: Negros Occidental and Negros Oriental. This division of the island, which roughly follows the mountain range in the center of the island, corresponds to the two related linguistic groups. The western half (Occidental) is home to the Hiligaynon Visayan-speaking population while the eastern half (Oriental) is home to the Cebuano Visayan-speaking population. Together, they are all called Negrenses. Kanlaon Volcano, located in the central-northern part of the island is the third most-active volcano in the Philippines and overlooks bordering communities and the city of Bacolod to the west. It is the highest peak of the whole island and of the Visayas. Other notable peaks on the island are Mount Silay and Mount Mandalagan in Negros Occidental and Mount Talinis (also known as Cuernos de Negros) in Negros Oriental. There are also lakes that dot the island, among the most notable are the Balinsasayao Twin Lakes in Negros Oriental. The volcanic activity in Negros is harnessed into electricity through two geothermal power plants in the island.
=== Zinc === Zinc is a necessary micronutrient which the human body uses to fight infections and childhood diarrhea. Collectively, zinc deficiencies are responsible for 4% of child morbidity and mortality, as of 2013. Fortification of staple foods such as breads may improve serum zinc levels in the human population, increasing immune strength. Zinc fortification has also been considered for reducing effects cognition, though the effectiveness is still under research.
Later on, however, Jean Améry—who had been tortured at Auschwitz—would sharply object that Adorno, rather than addressing such political concerns, was exploiting Auschwitz for his metaphysical phantom "absolute negativity" ("absolute Negativität"), using a language intoxicated by itself ("von sich selber bis zur Selbstblendung entzückte Sprache"). Adorno contended that the culture industry, through mass media, especially radio, had contributed to the development of fascism in Germany. In his view, the "authoritarian voice" arises from the intimacy of broadcast and social practices of radio listening. According to Adorno, "The authority of radio becomes greater the more it addresses the listener in his privacy," while "an organized mass of listeners might feel their own strength and even rise to a sort of opposition."
Sources: en.wikipedia.org
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.
Reduced pressure lowers the boiling point of water and allows ice to sublime below its triple point. Without sufficient vacuum, melting or boiling may occur instead of sublimation, which can damage the product structure.
Heat and mass transfer limit drying once the ice front recedes. The dried layer insulates the frozen core and resists vapor flow, so increasing shelf temperature too quickly can cause collapse or meltback.
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.