Everything below concerns Cake appearance. We keep the language plain, cite what the science says, and separate well-supported claims from open questions.
Updated 2026-08-01. Numbers and descriptions here follow the published literature rather than marketing material.
Lyophilization is a dehydration technique in which a product is frozen and the solvent is removed under reduced pressure. The low pressure allows ice to sublimate directly into vapor without passing through a bulk liquid phase. This differs from conventional drying, where heat drives evaporation and can damage heat-sensitive structures. The process is used for biological materials, pharmaceutical formulations, and some foods. Its main advantage is preservation of porous structure and rapid reconstitution.
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.
Quality control for lyophilized materials includes visual inspection, residual moisture measurement, and reconstitution testing. Cake appearance can reveal process problems such as collapse, shrinkage, or meltback, although appearance alone does not prove potency. Residual moisture is commonly measured by Karl Fischer titration or by loss on drying. Reconstitution time is checked because a slow or incomplete dissolve can indicate a change in pore structure. Stability studies track these attributes over time under defined temperature and humidity conditions.
Analytical methods for lyophilized solids must account for the low moisture content and the fragile cake. Karl Fischer titration is widely used for water content, while near-infrared spectroscopy can measure moisture non-destructively in sealed containers. X-ray diffraction and modulated differential scanning calorimetry help identify crystalline or amorphous phases. Residual solvent analysis may be needed if organic solvents were used during formulation. The combination of these methods supports batch release and long-term stability assessment.
Lyophilized products are typically stored as sealed solids in vials or syringes. Moisture ingress is a major concern because many dried cakes are hygroscopic and can lose stability when exposed to humid air. Storage temperature depends on the formulation; some products are kept refrigerated, while others are stable at room temperature. Container closure integrity and headspace moisture are often monitored. Light protection may also be required for some photosensitive materials.
| Property | Value | Notes |
|---|---|---|
| Common synonyms | freeze-drying, lyophilisation, cryodesiccation | Lyophilization is common in pharmaceutical literature. |
| Typical chamber pressure during primary drying | 0.05–0.5 mbar (5–50 Pa) | Must remain below the triple point of water. |
| Typical shelf temperature during freezing | −40 to −20 °C | Lower temperatures may be used for eutectic systems. |
| Typical residual moisture after secondary drying | 0.5–3% w/w | Product-dependent; low moisture improves stability but can cause over-drying. |
| Typical analytical method for residual moisture | Karl Fischer titration or loss on drying | Thermogravimetric methods are also used. |
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.
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.
Quality control for lyophilized materials examines appearance, reconstitution time, residual moisture, and mechanical integrity. An acceptable cake is usually uniform and porous, though appearance alone does not prove stability. Karl Fischer titration is a common method for water content, while differential scanning calorimetry can reveal glass transition events. Stability studies track potency, aggregation, and moisture over time under defined temperature and humidity conditions. Specifications are product-specific and may include sterility and endotoxin tests for sterile preparations.
Misconceptions about lyophilization include the idea that dried products are indefinitely stable or that vacuum sealing eliminates all degradation. Chemical reactions can continue in the solid state, and some proteins lose activity even at low moisture. Another misconception is that any freeze-dryer cycle can be scaled by time alone; heat and mass transfer differ with equipment and load. Open questions remain about predicting long-term stability from short accelerated studies, particularly for amorphous formulations. Real-time stability data remain the standard for shelf-life assignment.
==== Storage ==== Eighty to ninety percent of the total body reserves of preformed vitamin A are in the liver (with 80–90% of this amount being stored in hepatic stellate cells and the remaining 10–20% being stored in hepatocytes). Fat is another significant storage site, while the lungs and kidneys may also be capable of storage.
==== Imaging ==== Ultrasound of the thyroid may be used to reveal whether structures are solid or filled with fluid, helping to differentiate between nodules and goitres and cysts. It may also help differentiate between malignant and benign lesions. When further imaging is required, a radiolabelled iodine-123 or technetium-99 uptake scan may take place. This can determine the size and shape of lesions, reveal whether nodules or goitres are metabolically active, and reveal and monitor sites of thyroid disease or cancer deposits outside the thyroid. A fine needle aspiration of a sample of thyroid tissue may be taken in order to evaluate a lesion seen on ultrasound which is then sent for histopathology and cytology. Computed tomography of the thyroid plays an important role in the evaluation of thyroid cancer. CT scans often incidentally find thyroid abnormalities, and thereby practically becomes the first investigation modality.
From the early days of the development of AI, there have been arguments put forward by ELIZA creator Joseph Weizenbaum and others about whether tasks that can be done by computers actually should be done by them, given the difference between computers and humans, and between quantitative calculations and qualitative, value-based judgements. In April 2023, it was reported that image generation AI has resulted in 70% of the jobs for video game illustrators in China being lost. In July 2023, developments in generative AI contributed to the 2023 Hollywood labor disputes. Fran Drescher, president of the Screen Actors Guild, declared that "artificial intelligence poses an existential threat to creative professions" during the 2023 SAG-AFTRA strike. Voice generation AI has been seen as a potential challenge to the voice acting sector. However, a 2025 study concluded that the US labor market had so far not experienced a discernible disruption from generative AI. Another study reported that Danish workers who used chatbots saved 2.8% of their time on average, and found no significant change in earnings or hours worked.
=== Differential diagnosis === The differential diagnosis for heel pain is extensive and includes pathological entities including: calcaneal stress fracture, septic arthritis, calcaneal bursitis, osteoarthritis, spinal stenosis involving the nerve roots of lumbar spinal nerve 5 (L5) or sacral spinal nerve 1 (S1), calcaneal fat pad syndrome, metastasized cancers from elsewhere in the body, hypothyroidism, gout, seronegative spondyloparthopathies such as reactive arthritis, ankylosing spondylitis, or rheumatoid arthritis (more likely if pain is present in both heels), plantar fascia rupture, and compression neuropathies such as tarsal tunnel syndrome or impingement of the medial calcaneal nerve. Diagnosis can usually be made based on medical history and physical examination. When a physician suspects a fracture, infection, or some other serious underlying condition, an X-ray is typical. X-rays are otherwise unnecessary.
Sources: en.wikipedia.org
== Works cited == Dill, Marshall (1954). "The Christian Trade Unions During the Last Years of Imperial Germany and the First Months of the Weimar Republic". Review of Social Economy. 12 (2). Taylor & Francis, Ltd.: 89–109. doi:10.1080/00346765400000024. ISSN 0034-6764. JSTOR 29767502. Retrieved 25 March 2024. Grünthal, Günther (1968). Reichsschulgesetz und Zentrumspartei in der Weimarer Republik. Beiträge zur Geschichte des Parlamentarismus und der politischen Parteien (in German). Droste. ISBN 978-3-7700-5056-7. Retrieved 27 November 2024. Grünthal, Günther (1979). ""Zusammenschluß" oder "Evangelisches Zentrum"? Ein Beitrag zur Geschichte der Deutschen Zentrumspartei in der Weimarer Republik". In Pöls, Werner (ed.). Staat und Gesellschaft im politischen Wandel. Beiträge zur Geschichte der modernen Welt (in German). Stuttgart: Klett Cotta. pp. 301–330. ISBN 9783129119006. Mitchell, Maria (2012). "Confessional Conflict in German History". The Origins of Christian Democracy: Politics and Confession in Modern Germany. Social History, Popular Culture, And Politics In Germany. University of Michigan Press. ISBN 978-0-472-02854-2. Retrieved 27 November 2024. Schmidgall, Markus (2012). Die Revolution 1918/19 in Baden. Karlsruhe Institute of Technology. ISBN 9783866447271.
== In plants == Oxidative burst acts as a defence mechanism to pathogen infection in plants. This is seen post PAMPs detection by cell-surface located receptors (e.g. FLS2 or EFR). As in animals, the production of reactive oxygen species in plants is mediated by NADPH oxidase. In plant immunity, the NADPH oxidase subunits RbohD and RbohF have overlapping functions are expressed in different tissues and at different levels. However, in contrast to animal phagocytes, wherein generated ROS are contained in the sealed phagolysosome, oxidative burst in plants is not contained. Consequently, generated ROS bear additional effects alongside pathogen toxicity. Hydrogen peroxide induces oxidative cross-linking of the plant’s cell wall glycoproteins. This reduces susceptibility to enzymatic degradation by pathogens. Systemic acquired resistance, which is analogous to innate immunity in animals, is also induced in the exposed plant cells. Hydrogen peroxide exposure may also result in hypersensitive response, which is the death of a small number of host cells at the site of infection, for the purpose of limiting pathogenic infection. ROS production in plants can be used as a readout for successful pathogen recognition via a luminol-peroxidase based assay.
=== Pharmaceutical products === Several currently marketed amphetamine formulations contain both enantiomers, including those marketed under the brand names Adderall, Adderall XR, Mydayis, Adzenys ER, Adzenys XR-ODT, Dyanavel XR, Evekeo, and Evekeo ODT. Of those, Evekeo (including Evekeo ODT) is the only product containing only racemic amphetamine (as amphetamine sulfate), and is therefore the only one whose active moiety can be accurately referred to simply as "amphetamine". Dextroamphetamine, marketed under the brand names Dexedrine and Zenzedi, is the only enantiopure amphetamine product currently available. A prodrug form of dextroamphetamine, lisdexamfetamine, is also available and is marketed under the brand name Vyvanse. As it is a prodrug, lisdexamfetamine is structurally different from dextroamphetamine, and is inactive until it metabolizes into dextroamphetamine. The free base of racemic amphetamine was previously available as Benzedrine, Psychedrine, and Sympatedrine. Levoamphetamine was previously available as Cydril. Many current amphetamine pharmaceuticals are salts due to the comparatively high volatility of the free base. However, oral suspension and orally disintegrating tablet (ODT) dosage forms composed of the free base were introduced in 2015 and 2016, respectively. Some of the current brands and their generic equivalents are listed below.
== Alternatives to the wound healing assay == Using label-free live cell imaging devices based on quantitative phase imaging, it has been shown that cell motility is highly correlated to wound healing and transwell assay results. The advantage of this fully automated approach is that quantification of cell motility does not require specific sample preparation, allowing cell proliferation to be simultaneously quantified as well.
The United States, having become the only global superpower, used that ideological victory to reinforce its leadership position in the new world order, proclaiming that "the United States and its allies are on the right side of history." This new world order is referred to as "liberal hegemony" in international relations theory. Using the peace dividend, the United States Armed Forces were able to cut much of its expenditure, but the level rose again to comparable heights after the September 11 attacks and the initiation of the war on terror in 2001. Accompanying NATO expansion, Ballistic Missile Defense (BMD) systems were installed in Eastern Europe. However, from a relatively-weak developing country, China appeared as a fledgling emerging superpower that would challenge the U.S. and liberal democracy, creating new potential for worldwide conflict. In response to the rise of China, the U.S. has strategically "rebalanced" to the Asia-Pacific region, but also began to retreat from international commitments in favor of its own interests. Starting from the 2020s onward, the perceived threat of global terrorism in the post-9/11 era has expanded beyond Middle Eastern jihadist groups, culminating in the United States and Canada designating several drug cartels and transnational criminal organizations as terrorist organizations in the context of narcoterrorism and the war on drugs. The 2020s also found the Monroe Doctrine once again playing a central role in US foreign policy.
Sources: en.wikipedia.org
== In tomatoes == Some, such as the California Poison Control Center, have claimed that unripe tomatoes and tomato leaves contain solanine. However, Mendel Friedman of the United States Department of Agriculture contradicts this claim, stating that tomatine, a relatively benign alkaloid, is the tomato alkaloid while solanine is found in potatoes. Food science writer Harold McGee has found scant evidence for tomato toxicity in the medical and veterinary literature.
The company was founded by Colonel Eli Lilly, a pharmaceutical chemist and Union army veteran of the American Civil War. Lilly served as the company president until his death in 1898. In 1869, after working for drugstores in Indiana, Lilly became a partner in a Paris, Illinois-based drugstore with James W. Binford. Four years later, in 1873, Lilly left the partnership with Binford, and returned to Indianapolis. In 1874, Lilly partnered with John F. Johnston, and opened a drug manufacturing operation called Johnston and Lilly. In 1876, Lilly dissolved the partnership, and used his share of the assets to open his own pharmaceutical manufacturing business, Eli Lilly and Company, in Indianapolis. The sign outside, above the shop's door, read: "Eli Lilly, Chemist." The Indiana Historical Society recreated a replica of the first Lilly laboratory on Pearl Street for its exhibition, "You Are There: Eli Lilly at the Beginning," at the Eugene and Marilyn Glick Indiana History Center in Indianapolis. The temporary exhibition (1 October 2016, to 20 January 2018) also included costumed interpreters portraying Colonel Lilly and others. In 1886, Ernest G. Eberhardt, a chemist, joined the company as its first full-time research scientist. Lilly began his manufacturing venture with three employees, including his son, Josiah (J. K.). One of the first medicines that Lilly produced was quinine, a drug used to treat malaria, a mosquito-borne disease. By the end of 1876, sales reached $4,470. Around 1890, Col.
EGF is the founding member of the EGF-family of proteins. Members of this protein family have highly similar structural and functional characteristics. Besides EGF itself other family members include:
== Overview == Generally, it is considered that a hyperbolic structured protein in specific media conditions is ready to do its task, it is active, but some specific deactivation, are responsible for the regulation of some metabolism pathways. Regulatory enzymes are commonly the first enzyme in a multienzyme system: the product of the reaction catalyzed by the first enzyme is the substrate of the second enzyme, so the cell can control the amount of resulting product by regulating the activity of the first enzyme of the pathway. There are many strategies of activation and deactivation of regulatory enzymes. Regulatory enzymes require an extra activation process and need to pass through some modifications in their 3D in order to become functional, for instance, catalyzing enzymes (regulatory enzymes). The regulation of the activation of these catalyzing enzymes is needed in order to regulate the whole reaction speed, so that it is possible to obtain the amount of product required at any time, that makes regulatory enzymes have a biological importance. Therefore, regulatory enzymes, by its controlled activation and are of two types: allosteric enzymes and covalently modulated enzymes; however, an enzyme can combine both types of regulation.
Sources: en.wikipedia.org
Yes, the terms are generally interchangeable. Lyophilization is more common in pharmaceutical and laboratory contexts, while freeze-drying appears widely in food science and general writing. Both describe removal of solvent by sublimation under vacuum after freezing.
Reduced pressure keeps the process below the triple point of water, so ice can sublimate directly to vapor. It also lowers the temperature needed for drying, which helps preserve heat-sensitive materials. Without vacuum, melting or boiling could occur instead of controlled sublimation.
The rate depends on heat transfer to the product and mass transfer of vapor through the dried layer. A cold condenser, adequate vacuum, and suitable shelf temperature all influence speed. Formulation properties such as solid content and collapse temperature also set practical limits.
Most lyophilized products are stored in sealed containers at controlled temperature and humidity. Some require refrigeration, while others are stable at room temperature. Protection from light and moisture is often necessary.