The short version of residual moisture fits in a sentence. The long version — which is the one that helps — is below.
Reviewed 2026-05-23. Anything still debated is marked as such rather than presented as settled.
Lyophilization, also called freeze-drying, removes water from a frozen material by sublimation under reduced pressure. The process begins with freezing, which converts free water into ice and may also produce a glassy phase. Primary drying then lowers chamber pressure so ice sublimes directly to vapor without passing through a liquid stage. Secondary drying raises the temperature modestly to remove bound water. The result is a porous, dry solid that usually reconstitutes quickly. Each stage influences pore structure, residual moisture, and stability.
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.
The process usually has three stages: freezing, primary drying, and secondary drying. Freezing sets the ice crystal structure and can determine pore size in the final cake. Primary drying removes free ice by sublimation at low pressure and low shelf temperature. Secondary drying removes bound water by raising the shelf temperature, although some water may remain as part of the solid. Cycle parameters depend on formulation, fill volume, vial type, and equipment performance.
The physical chemistry of freezing influences whether a formulation forms an amorphous glass or a crystalline solid. Amorphous systems can collapse if product temperature rises above the glass transition temperature of the freeze concentrate. Crystalline systems may show eutectic melting, where ice and solute melt together at a fixed temperature. Formulators add bulking agents, lyoprotectants, and buffers to preserve structure and biological activity. The optimum cycle keeps product temperature below critical thresholds during primary drying while allowing efficient sublimation.
| Property | Value | Notes |
|---|---|---|
| Common synonyms | Freeze-drying; lyophilisation; cryodesiccation | Regional spelling and historical terms. |
| Primary drying pressure | 0.05-0.5 mbar (5-50 Pa) | Kept below the triple point of water; product-specific. |
| Shelf temperature range | -40 to +40 °C | Freezing, primary, and secondary stages use different set points. |
| Cycle duration | 12-72 hours | Depends on fill volume, formulation, and equipment. |
| Condenser temperature | -50 to -80 °C | Must remain below the product's ice temperature. |
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 process relies on the phase diagram of water, where the triple point marks the conditions at which ice, liquid water, and vapor coexist. By maintaining pressure below this point, typically around 0.01 to 0.1 millibar, sublimation becomes the dominant mechanism. Formulations often include excipients such as sugars or polymers that act as lyoprotectants and bulking agents. These additives help preserve the structure of the active ingredient and prevent collapse during drying. The choice of excipient and freezing rate influences the final cake morphology and stability.
Freezing is the first stage and sets the ice structure that later becomes the pore network. The formulation is cooled below its freezing point, often with a controlled ramp, and solutes concentrate as ice forms. Primary drying then lowers chamber pressure and supplies heat to sublime the ice. The product temperature must stay below its collapse or eutectic temperature to prevent structural loss. Secondary drying raises the temperature modestly to remove bound water and achieve a low residual moisture.
A freeze-dryer consists of a vacuum chamber, temperature-controlled shelves, a condenser, and a vacuum pump. Vials, ampoules, or bulk trays hold the product during the cycle. The condenser traps water vapor as ice at a temperature lower than the product. Cycle development balances shelf temperature, chamber pressure, and time. Scale-up can be difficult because heat and mass transfer change with equipment size, so process analytical tools and conservative validation are often used.
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.
Soy sauce is made either by fermentation or by hydrolysis. Some commercial sauces have both fermented and chemical sauces. Flavor, color, and aroma developments during production are attributed to non-enzymatic Maillard browning. Variation is usually achieved as the result of different methods and durations of fermentation, different ratios of water, salt, and fermented soy, or through the addition of other ingredients.
In manufacturing, the simulated moving bed (SMB) process is a highly engineered process for implementing chromatographic separation. It is used to separate one chemical compound or one class of chemical compounds from one or more other chemical compounds to provide significant quantities of the purified or enriched material at a lower cost than could be obtained using simple (batch) chromatography. It cannot provide any separation or purification that cannot be done by a simple column purification. The process is rather complicated. The single advantage which it brings to a chromatographic purification is that it allows the production of large quantities of highly purified material at a dramatically reduced cost. The cost reductions come about as a result of: the use of a smaller amount of chromatographic separation media stationary phase, a continuous and high rate of production, and decreased solvent and energy requirements. This improved economic performance is brought about by a valve-and-column arrangement that is used to lengthen the stationary phase indefinitely and allow very high solute loadings to the process. In the conventional moving bed technique of production chromatography the feed entry and the analyte recovery are simultaneous and continuous, but because of practical difficulties with a continuously moving bed, the simulated moving bed technique was proposed.
Clinical outcomes include depressed growth, diarrhea, impotence and delayed sexual maturation, alopecia, eye and skin lesions, impaired appetite, altered cognition, impaired immune functions, defects in carbohydrate use, and reproductive teratogenesis. Zinc deficiency depresses immunity, but excessive zinc does also. Despite some concerns, western vegetarians and vegans do not suffer any more from overt zinc deficiency than meat-eaters. Major plant sources of zinc include cooked dried beans, sea vegetables, fortified cereals, soy foods, nuts, peas, and seeds. However, phytates in many whole-grains and fibers may interfere with zinc absorption and marginal zinc intake has poorly understood effects. The zinc chelator phytate, found in seeds and cereal bran, can contribute to zinc malabsorption. Some evidence suggests that more than the US RDA (8 mg/day for adult women; 11 mg/day for adult men) may be needed in those whose diet is high in phytates, such as some vegetarians. The European Food Safety Authority (EFSA) guidelines attempt to compensate for this by recommending higher zinc intake when dietary phytate intake is greater. These considerations must be balanced against the paucity of adequate zinc biomarkers, and the most widely used indicator, plasma zinc, has poor sensitivity and specificity.
In South America, Colombia has been in the midst of a civil war which has been waged since 1964 between the Colombian government and aligned right-wing paramilitaries against two Marxist–Leninist guerrilla groups, namely the National Liberation Army and Revolutionary Armed Forces of Colombia. In Peru, there has been an internal conflict between the Peruvian government and Marxist–Leninist–Maoist militants including the Shining Path. The 2021 Peruvian general election was won by presidential candidate Pedro Castillo on the Marxist–Leninist program put forward by Free Peru. The early 21st century also saw the election of socialist governments in several Latin American nations, in what has come to be known as the "pink tide"; dominated by the Venezuelan government of Hugo Chávez; this trend also saw the election of Evo Morales in Bolivia, Rafael Correa in Ecuador, and Daniel Ortega in Nicaragua. Forging political and economic alliances through international organisations like the Bolivarian Alliance for the Americas, these socialist governments allied themselves with Marxist–Leninist Cuba. Although none espoused a Stalinist path directly, most admitted to being significantly influenced by Marxist theory. Venezuelan president Hugo Chávez declared himself a Trotskyist during the swearing-in of his cabinet two days before his inauguration on 10 January 2007.
Sources: en.wikipedia.org
The recent epidemic increase of obesity prevalence has thus contributed to changes in the prevalence and in the characteristics of pediatric OSA, the severity of OSA is proportional to the degree of obesity. Obesity leads to narrowing of the upper airway structure due to fatty infiltration and fat deposits in the anterior neck region and cervical structures. Alongside with the additional weight loading on the respiratory system, it increases the risk of pharyngeal collapsibility while reducing the intrathoracic volume and diaphragm excursion. Moreover, excessive daytime sleepiness resulting from sleep fragmentation can decrease physical activity and thus lead to weight gain (by sedentary habits or increased food intake to overcome somnolence). The obesity-related obstruction of upper airway structure has led some authors to distinguish between two types of OSA in children: type I is associated with marked lymphadenoid hypertrophy without obesity and type II is first associated with obesity and with milder upper airway lymphadenoid hyperplasia. The two types of OSA in children can result in different morbidities and consequences. Studies have shown that weight loss in obese adolescents can reduce sleep apnea and thus the symptoms of OSA.
The Chinese associated the five elements with the five planets (Jupiter, Mars, Venus, Saturn, and Mercury) similar to the way the classical planets were associated with different metals. The yin and yang distinction approximates the modern notion of solid and hollow organs.
=== Calcium oxalate production === Chocolate has oxalic acid, which reacts with the calcium in the milk producing calcium oxalate, thus preventing the calcium from being absorbed in the intestine. However, it is present in small enough amounts that the effect on calcium absorption is negligible (2–3%). As chocolate contains relatively small amounts of oxalate, it is unclear to what extent chocolate consumption affects healthy people with calcium-rich diets. In a 2008 study, participants who consumed one or more servings of chocolate on a daily basis had lower bone density and strength than those participants who ate a serving of chocolate six times a week or less. Researchers believe this may be due to oxalate inhibiting calcium absorption – but it could also be due to sugar content in chocolate, which may increase calcium excretion. It is clear, however, that consuming foods high in oxalate – and in turn their effect on calcium absorption – is a more significant concern for people with oxalate kidney stones, which occur when there is too much oxalate in the urine. These people especially should reduce their oxalate intake and increase their calcium intake. However, the high magnesium content in chocolate is likely to reduce the risk of stone formation, because like citrate, magnesium is also an inhibitor of urinary crystal formation.
The amendments gave the general counsel of the National Labor Relations Board discretionary power to seek injunctions against either employers or unions that violated the act. The law made pursuit of such injunctions mandatory, rather than discretionary, in the case of secondary boycotts by unions. The amendments also established the general counsel's autonomy within the administrative framework of the NLRB. Congress also gave employers the right to sue unions for damages caused by a secondary boycott, but gave the general counsel exclusive power to seek injunctive relief against such activities.
== Development == C. brunneus are hemimetabolous. Females lay eggs over a 10-week period in the soil. Eggs hatch as early as April. Hatchlings typically go through four nymphal stages before becoming adults. Adults can live into the late autumn.
Sources: en.wikipedia.org
Four entities are given authority under the drug conventions: the Commission on Narcotic Drugs (CND), the UN Office on Drugs and Crime (UNODC), the International Narcotics Control Board (INCB), and the World Health Organization (WHO). The 53-member CND, a subsidiary organ of the Economic and Social Council (ECOSOC), is the UN's main drug policy body, responsible for the drug classification schedules and policy guidance. Members are elected by ECOSOC, one of the six UN main organs. The CND also is the governing body of the UNODC, which advises governments on implementation of the conventions and produces an annual World Drug Report. UNODC's focus is mainly on security and law enforcement, rather than public health. The INCB is an independent treaty body, mandated by the Single Convention, that monitors implementation of the conventions, oversees the legal drug supply, and maintains discussions with countries regarding compliance issues. Central to its function is an annual set of reports, submitted to ECOSOC through the CND, that overlook the global drug situation. The reporting identifies and predicts problem trends and suggests corrective actions. Technical reports list estimated national requirements, and production, manufacture, trade and consumption data, for controlled drugs for medical and scientific use, gathered from individual countries. Trends in trafficking in precursors and essential chemicals for illicit drug manufacture, and evaluation of government measures taken to prevent that traffic, are also reported.
retinoblastoma protein (pRb) binding motif; cyclin box domain for cyclin-dependent kinase (CDK) binding and CDK inhibitor binding; LxxLL binding motif for co-activator recruitment; PEST sequence that may mark the protein for degradation; threonine residue (threonine 286) that controls nuclear export and protein stability.
==== Physical performance ==== Caffeine is a proven ergogenic aid in humans. Caffeine improves athletic performance in aerobic (especially endurance sports) and anaerobic conditions. Moderate doses of caffeine (around 5 mg/kg) can improve sprint performance, cycling and running time trial performance, endurance (i.e., it delays the onset of muscle fatigue and central fatigue), and cycling power output. Caffeine increases basal metabolic rate in adults. Caffeine ingestion prior to aerobic exercise increases fat oxidation, particularly in persons with low physical fitness. Caffeine improves muscular strength and power, and may enhance muscular endurance. Caffeine also enhances performance on anaerobic tests. Caffeine consumption before constant load exercise is associated with reduced perceived exertion. While this effect is not present during exercise-to-exhaustion exercise, performance is significantly enhanced. This is congruent with caffeine reducing perceived exertion, because exercise-to-exhaustion should end at the same point of fatigue. Caffeine also improves power output and reduces time to completion in aerobic time trials, an effect positively (but not exclusively) associated with longer duration exercise.
Early diagenesis in newly formed aquatic sediments is mediated by microorganisms using different electron acceptors as part of their metabolism. Organic matter is mineralized, liberating gaseous carbon dioxide (CO2) in the porewater, which, depending on the conditions, can diffuse into the water column. The various processes of mineralization in this phase are nitrification and denitrification, manganese oxide reduction, iron hydroxide reduction, sulfate reduction, and fermentation.
Sources: en.wikipedia.org
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.
Reduced pressure lowers the boiling point of water and allows ice to sublime at temperatures below freezing. It also helps remove water vapor from the product toward the condenser. The exact pressure is chosen to stay below the triple point of water.
No. Materials with low solids content or high volatile solvents may form weak or collapsed cakes. Some proteins and cells require stabilizers to survive freezing and drying stresses. Feasibility depends on formulation and process design.
The main change is sublimation, in which ice becomes water vapor without melting into liquid water. This occurs when the chamber pressure is held below the vapor pressure of ice while mild heat is supplied. The result is a dry, porous solid that retains much of its original shape.