Everything below concerns Sublimation. We keep the language plain, cite what the science says, and separate well-supported claims from open questions.
Last reviewed on 2026-05-11. Where a claim depends on a specific study, the study is described rather than over-claimed.
Secondary drying removes bound water that remains after ice sublimation. Shelf temperature is raised gradually while pressure remains low, reducing water content to a target range. Over-drying can cause brittleness or electrostatic issues, while under-drying affects stability. The endpoint is often judged by pressure rise tests, temperature measurements, or water content analysis. Scale-up depends on matching heat and mass transfer across equipment sizes. Small changes in shelf temperature or pressure can alter cycle length substantially.
Lyophilization, or freeze-drying, removes water from a material by freezing it and then lowering pressure so ice changes directly to vapor. The process relies on sublimation, the phase transition from solid to gas without an intervening liquid state. It is used for heat-sensitive materials that would degrade in conventional drying. The three stages are freezing, primary drying, and secondary drying, each with distinct temperature and pressure requirements. In practice, cycle design balances these variables.
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.
After lyophilization, the dried product is often sealed under vacuum or an inert gas to limit moisture and oxygen exposure. Vials, stoppers, and seals must maintain their barrier throughout shelf life. Storage temperature depends on product sensitivity: some cakes tolerate controlled room temperature, while labile biologics require refrigeration. Humidity is a critical variable because dried cakes are hygroscopic and can absorb water when exposed to air. Handling procedures therefore limit open-vial time and use desiccated environments for sampling.
| Property | Value | Notes |
|---|---|---|
| Process name | Lyophilization or freeze-drying | Both terms appear in technical standards and literature. |
| Phase transition | Sublimation | Solid ice becomes vapor without a liquid step. |
| Typical chamber pressure | 0.05-0.5 mbar | Range depends on product temperature and equipment. |
| Typical product temperature | -40 °C to -10 °C | Measured during primary drying; formulation sets limits. |
| Water content after drying | 0.5-3% w/w | Target varies by material and stability needs. |
=== Putsch === The term putsch ([pʊtʃ], from Swiss German for 'knock') denotes the political-military actions of a minority reactionary coup. The term was initially coined for the Züriputsch of 6 September 1839 in Switzerland. It was also used for attempted coups in Weimar Germany, such as the 1920 Kapp Putsch, Küstrin Putsch, and Adolf Hitler's 1923 Beer Hall Putsch. The 1934 Night of the Long Knives was Hitler's purge to eliminate opponents, particularly the paramilitary faction led by Ernst Röhm, but Nazi propaganda justified it as preventing a supposed putsch planned or attempted by Röhm. The Nazi term Röhm-Putsch is still used by Germans to describe the event, often with quotation marks as the 'so-called Röhm Putsch'. The 1961 Algiers putsch and the 1991 August Putsch also use the term. The 2023 Wagner Group rebellion has also been described as a putsch.
However, this apparent occupancy could alternatively be due to increased serotonin release during migraine attacks. In contrast to receptor antagonists, it is notable that agonists require only a low fractional receptor occupancy to produce central effects. Relatedly, the serotonin 5-HT1B receptor occupancy observed with sumatriptan was comparable to that with centrally acting opioids. Besides the clinical findings, further animal studies have found that sumatriptan rapidly enters the brain in spite of its poor lipophilicity and was able to do so more quickly than the benzodiazepine oxazepam.
Bohr provided a derivation based on an atomic model, a result taken as substantial evidence in favor of his model. Bohr also used he model to describe the structure of the periodic table and aspects of chemical bonding. Together these results lead to Bohr's model being widely accepted by the end of 1915. Bohr's model was not perfect. It could only predict the spectral lines of hydrogen, not those of multielectron atoms. Worse still, it could not even account for all features of the hydrogen spectrum: as spectrographic technology improved, it was discovered that applying a magnetic field caused spectral lines to multiply in a way that Bohr's model couldn't explain. In 1916, Arnold Sommerfeld added elliptical orbits to the Bohr model to explain the extra emission lines, but this made the model very difficult to use, and it still couldn't explain more complex atoms.
This flaw is supported by the FAO/WHO/UNU, who state that BV and NPU are measured when the protein content of the diet is clearly below that of requirement, deliberately done to maximize existing differences in quality as inadequate energy intake lowers the efficiency of protein utilization and in most N balance studies, calorie adequacy is ensured. And because no population derives all of its protein exclusively from a single food, the determination of BV of a single protein is of limited use for application to human protein requirements. Another limitation of the use of Biological Value as a measure of protein quality is that proteins which are completely devoid of one essential amino acid (EAA) can still have a BV of up to 40. This is because of the ability of organisms to conserve and recycle EAAs as an adaptation of inadequate intake of the amino acid. Lastly, the use of rats for the determination of protein quality is not ideal. Rats differ from humans in requirements of essential amino acids. This has led to a general criticism that experiments on rats lead to an over-estimation of the BV of high-quality proteins to man because human requirements of essential amino acids are much lower than those for rats (as rats grow at a much faster rate than humans). Also, because of their fur, rats are assumed to have relatively high requirements of sulphur-containing amino acids (methionine and cysteine). As a result, the analytical method that is universally recognized by the Food and Agriculture Organization (FAO), World Health Organization (WHO), the U.S.
Selenium compounds can be used both as decolourising agents and to add a red colour to glass. Decorative glassware made of traditional lead glass contains at least 30% lead(II) oxide (PbO); lead glass used for radiation shielding may have up to 65% PbO. Lead-based glasses have also been extensively used in electronic components, enamelling, sealing and glazing materials, and solar cells. Bismuth based oxide glasses have emerged as a less toxic replacement for lead in many of these applications.
Sources: en.wikipedia.org
== Relationship between GnRH and GnSAF == GnRH and GnSAF are functionally antagonistic over the control of LH secretion in the hypothalamic-pituitary axis. In the presence of GnSAF, endogenous pulses of GnRH from the hypothalamus still persist, in approximately one hour intervals. Due to this large time interval between consecutive GnRH pulses, GnSAF effectively limits the effects of GnRH on the anterior pituitary. GnSAF acts on the gonadotropic cells of the pituitary to neutralise the second messenger pathway responsible for transducing GnRH signalling in the gonadotropes. The effectiveness of downstream actions of GnRH, such as calcium mobilisation and the protein kinase C system, are reduced by GnSAF. These antagonistic effects of GnSAF on GnRH keeps the anterior pituitary in a low responsiveness state, which prevents acute elevations of serum LH concentrations until GnSAF bioactivity declines. When estradiol concentrations are high in the late follicular phase, GnRH pulse frequency and amplitude increases and overrides the attenuating effects of GnSAF. Frequent and consecutive exogenous administration of GnRH at submaximal doses is sufficient in overcoming the neutralizing effects of GnSAF. This is because estradiol lowers the GnRH pulse frequency and amplitude required to stimulate the biosynthesis and secretion of LH.
The cyclopropenium ion is the cation with the formula C3H+3. It has attracted attention as the smallest example of an aromatic cation. Its salts have been isolated, and many derivatives have been characterized by X-ray crystallography. The cation and some simple derivatives have been identified in the atmosphere of the Saturnian moon Titan.
The Union's Senior Member (the university don that every society was required to have) resigned in protest at what he saw as Heseltine's profligacy, and was replaced by the young Maurice Shock. At the end of the Trinity (summer) Term 1954, Heseltine was elected President of the Oxford Union for Michaelmas term 1954, largely on the strength of his business management, and with the assistance of Union contemporaries Jeremy Isaacs and Anthony Howard, the then chairman and chairman-elect of the Oxford University Labour Club; Heseltine had even, for a brief period that term, joined a protest group against the Conservative government's testing of an H-Bomb. He had done little study at University, and passed his finals with the help of last-minute coaching from friends. After graduating with a second-class degree in Philosophy, politics and economics, described by his tutor Neville Ward-Perkins as "a great and undeserved triumph", he was permitted to stay on for an extra term to serve as Union President. The Union cellars were opened on 30 October 1954, and Heseltine persuaded the visiting Sir Bernard and Lady Docker to contribute to the considerable cost. Debates over which he presided included censorship of the Arts (no vote taken), welcoming the decline of British Imperialism (defeated 281–381) and calling for a "change in the principles and practice of British Trade Unions" (carried 358–200).
A protein kinase is a kinase which selectively modifies other proteins by covalently adding phosphates to them (phosphorylation) as opposed to kinases which modify lipids, carbohydrates, or other molecules. Phosphorylation usually results in a functional change of the target protein (substrate) by changing enzyme activity, cellular location, or association with other proteins. The human genome contains about 500 protein kinase genes and they constitute about 2% of all human genes. There are two main types of protein kinase. The great majority are serine/threonine kinases, which phosphorylate the hydroxyl groups of serines and threonines in their targets. Most of the others are tyrosine kinases, although additional types exist. Protein kinases are also found in bacteria and plants. Up to 30% of all human proteins may be modified by kinase activity, and kinases are known to regulate the majority of cellular pathways, especially those involved in signal transduction.
Sources: en.wikipedia.org
is chosen to represent the change in potential energy per unit charge flowing into the cell as above. Furthermore, due to redox-driven proton pumping by coupling sites, the proton gradient is always inside-alkaline. For both of these reasons, protons flow in spontaneously, from the P side to the N side; the available free energy is used to synthesize ATP (see below). For this reason, PMF is defined for proton import, which is spontaneous. PMF for proton export, i.e., proton pumping as catalyzed by the coupling sites, is simply the negative of PMF(import). The spontaneity of proton import (from the P to the N side) is universal in all bioenergetic membranes. This fact was not recognized before the 1990s, because the chloroplast thylakoid lumen was interpreted as an interior phase, but in fact it is topologically equivalent to the exterior of the chloroplast. Azzone et al. stressed that the inside phase (N side of the membrane) is the bacterial cytoplasm, mitochondrial matrix, or chloroplast stroma; the outside (P) side is the bacterial periplasmic space, mitochondrial intermembrane space, or chloroplast lumen. Furthermore, 3D tomography of the mitochondrial inner membrane shows its extensive invaginations to be stacked, similar to thylakoid disks; hence the mitochondrial intermembrane space is topologically quite similar to the chloroplast lumen.: The energy expressed here as Gibbs free energy, electrochemical proton gradient, or proton-motive force (PMF), is a combination of two gradients across the membrane:
The industrial manufacture of silicone breast prostheses employs the metallic element platinum (Pt, 78) as a catalyst for chemically transforming liquid silicone oil into viscous silicone gel, the elastomer material for making breast-implant shells. Occasionally, trace quantities of platinum leak from a prosthetic breast into the woman's body and accumulate in the bone marrow, from where red blood cells would deposit the trace-platinum upon nerve endings and consequently cause disorders of the nervous system, such as blindness, deafness, and nervous tics (involuntary muscle contractions). The FDA's review of the trace-platinum-toxicity data about the silicone-gel used for making prosthetic breasts said that the type of platinum used in modern silicone breast implants is not ionized platinum, and so not a biological risk to women with such prosthetic breasts. That there were no reports of trace-platinum-toxicity and no causal relation between the metal in the silicone-gel and the occurrence of trace-platinum-toxicity among women with silicone-gel prosthetic breasts.
Taletrectinib, sold under the brand name Ibtrozi, is an anti-cancer medication used for the treatment of non-small cell lung cancer. It is used as the salt, taletrectinib adipate. Taletrectinib is a kinase inhibitor. It is taken by mouth. Taletrectinib was approved for medical use in the United States in June 2025.
(2026) reconstruct the evolutionary history of members of the genus Arvicola in Western Europe during the late Middle and Late Pleistocene on the basis of the study of morphology of teeth from the Lazaret Cave and Moula-Guercy sites (France), Abauntz Cave, Cova Eirós (Spain) and Trou Al'Wesse (Belgium), interpreted as consistent with a complex biogeographic history including multiple dispersals into Western Europe and subsequent local extinctions and recolonizations. New fossil material of members of the genus Byzantinia, providing new information on the morphology of teeth of members of this genus and their evolution, is described from the Miocene strata of the Zahleh Formation (Lebanon) by López-Antoñanzas et al. (2026). A study on the phylogenetic relationships and evolutionary history of extant and extinct hamsters is published by Dirnberger et al. (2026). Bujalska et al. (2026) reconstruct the evolutionary history of European small hamsters on the basis of mitochondrial genomes from Late Pleistocene and Holocene remains from Central and Western Europe, the Balkans and Anatolia, identifying evidence of presence of the winter white dwarf hamster in Central Europe during the Late Pleistocene. Pacheco-Castro, Carranza-Castañeda & Wang (2026) report the discovery of fossil material of Sigmodon minor from the Pliocene strata of the San Miguel de Allende Basin, representing the first record of the species from central Mexico and its southernmost known record in North America.
All FSL Kode constructs disperse in water and are therefore compatible with inkjet printers. FSL constructs can be printed with a standard desktop inkjet printer directly onto paper to create immunoassays. An empty ink cartridge is filled with an FSL construct and words, barcodes, or graphics are printed. A Perspex template is adhered to the surface to create reaction wells. The method is then a standard EIA procedure, but blocking of serum is not required and undiluted serum can be used. A typical procedure is as follows: add serum, incubate, wash by immersion, add secondary EIA conjugate, incubate, wash, add NBT/BCIP precipitating substrate and stop the reaction when developed by washing (Fig. 9). The result is stable for years.
Sources: en.wikipedia.org
Conventional drying uses heat to evaporate liquid water, often at temperatures that can degrade sensitive materials. Lyophilization freezes the material first and then removes water by sublimation under vacuum. This avoids prolonged exposure to liquid water and high heat.
Lowering pressure reduces the boiling point of water and allows ice to sublimate at temperatures below freezing. Vacuum also limits convective heat transfer, so heat is usually supplied by shelves or radiation. The pressure must stay below the vapor pressure of ice at the product temperature.
The cycle typically includes freezing, primary drying, and secondary drying. Freezing solidifies water and sets the pore structure; primary drying removes bulk ice; secondary drying removes bound water. Some cycles add annealing or pre-freezing steps.
No. Freeze-drying removes water but does not reliably kill microorganisms. Sterile lyophilized products are typically prepared aseptically before freezing or are sterilized by a validated method. Microbial control depends on the entire manufacturing process.