This is a working overview of Primary drying, written for readers who want more than a one-paragraph summary but less than a textbook.
This page was last updated on 2026-07-05 and is reviewed periodically as new material appears.
Storage stability depends on water content, oxygen exposure, and temperature. Lyophilized solids are hygroscopic and can absorb water if exposed to humid air. Vials are usually sealed under vacuum or inert gas with rubber stoppers and aluminum crimps. Storage temperatures range from room temperature to refrigerated or frozen conditions depending on the material. Stability studies track potency, moisture, and physical form over time. Accelerated conditions can reveal sensitivity but may not predict long-term behavior.
Analytical methods for lyophilized materials include X-ray diffraction for crystallinity, differential scanning calorimetry for thermal transitions, and scanning electron microscopy for pore morphology. Moisture sorption analysis shows how the cake responds to humidity. These methods help distinguish amorphous from crystalline states and detect phase changes. Open questions remain about how pore structure changes during long-term storage and how best to predict collapse under varied conditions. Comparisons across studies are complicated by differences in formulation, cycle, and storage history.
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.
| Property | Value | Notes |
|---|---|---|
| Appearance | White to off-white porous cake | Color and texture vary with formulation. |
| Reconstitution time | Seconds to several minutes | Depends on cake porosity, excipients, and diluent. |
| Typical moisture level | 0.5-3% w/w | Lower values suit hydrolysis-sensitive materials. |
| Common moisture method | Karl Fischer titration | Coulometric mode is common for low water levels. |
| Typical storage temperature | 2-8 °C or ambient | Some products require frozen storage; protect from humidity. |
Stability programs monitor lyophilized products under defined temperature and humidity conditions over time. Real-time studies at recommended storage conditions are the reference, while accelerated studies provide early signals of degradation pathways. Because a dry cake can still undergo oxidation, hydrolysis, or aggregation, stability depends on residual moisture, excipients, and container headspace. Open questions include how best to predict long-term stability from short accelerated runs and how vial-to-vial variability affects shelf life. Current guidance treats these predictions as product-specific rather than universally generalizable.
Freeze-dried materials are hygroscopic to varying degrees and can take up moisture after drying. Storage therefore often uses sealed glass vials, rubber stoppers, and crimp seals to limit contact with ambient humidity. A desiccant may be included for moisture-sensitive products, although it is not universal. Controlled room temperature is sufficient for many lyophilizates, while others require refrigeration or freezing. Moisture ingress remains a primary cause of cake collapse, chemical degradation, and loss of reconstitution 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.
Lyophilization is a dehydration process that removes water from a frozen material by sublimation under low pressure. The material is first frozen so that water becomes ice; then the surrounding pressure is lowered below the vapor pressure of ice. Heat is applied gently so ice changes directly to vapor without passing through a bulk liquid phase. The vapor is collected on a cold condenser, leaving a dry porous matrix. This process differs from simple evaporation because the material remains frozen during the main drying stage.
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.
Quality control for freeze-dried forms includes visual inspection, water content measurement, and reconstitution time. A satisfactory cake is typically uniform, porous, and intact, although minor shrinkage or cracking may be acceptable if specifications allow. Karl Fischer titration, thermal gravimetric analysis, and near-infrared spectroscopy are used to measure water content. Reconstitution is assessed by adding a specified diluent and recording the time and ease of dissolution. Microbiological and particulate tests are added when the product is sterile or intended for injection.
Stability of a lyophilized solid depends on water content, temperature, and the physical state of the formulation. Amorphous products may slowly absorb moisture and drop below their glass transition temperature, causing collapse or crystallization. Some proteins and peptides can aggregate even in a dry state, especially when exposed to heat or moisture. Accelerated stability studies at elevated temperature and humidity help estimate shelf life, but real-time data remain the basis for expiration dating.
After drying, a lyophilized product is usually sealed under vacuum or an inert gas to limit moisture and oxygen exposure. The container closure system matters because stoppers and seals can allow moisture ingress over time. Storage conditions are selected from stability studies that track potency, cake appearance, and reconstitution behavior. Many freeze-dried materials are kept at controlled room temperature, while some require refrigeration or protection from light.
Patients with keratoconus typically present initially with mild astigmatism and myopia, commonly at the onset of puberty, and are diagnosed by the late teenage years or early 20s. The disease can, however, present or progress at any age; in rare cases, keratoconus can present in children or not until later adulthood. A diagnosis of the disease at an early age may indicate a greater risk of severity in later life. Patients' vision will seem to fluctuate over a period of months, driving them to change lens prescriptions frequently, but as the condition worsens, contact lenses are required in the majority of cases. The course of the disorder can be quite variable, with some patients remaining stable for years or indefinitely, while others progress rapidly or experience occasional exacerbations over a long and otherwise steady course. Most commonly, keratoconus progresses for a period of 10 to 20 years before the course of the disease generally ceases in the third and fourth decades of life.
Here, Mr(X) is the relative molar mass, also called molecular weight or formula weight. For normal samples from Earth with typical isotope composition, the standard atomic weight or the conventional atomic weight can be used as an approximation of the relative atomic mass of the sample. Examples are:
Believing that a deficiency in political theory was being filled by the entryist infiltration of the party by the Trotskyists (such as the Militant tendency), he thought the problem was better resolved by communist thinking from members of the CPGB. (He was later opposed to the expulsion of members of Militant.) In response, Denis Healey, Deputy Leader of the Labour Party, tried and failed to remove Galloway from the list of prospective parliamentary candidates. Healey lost his motion by 13 votes to five. Galloway once quipped that, to overcome a £1.5 million deficit which had arisen in Dundee's city budget, he, Ernie Ross, and leading councillors should be placed in the stocks in the city square: "We would allow people to throw buckets of water over us at 20p a time." In 1983, Galloway attempted to stand for the safe Labour seat of Rhondda after the Welsh Transport and General Workers' Union and the National Union of Miners had both nominated him to succeed Alec Jones, who had died. He hoped to be selected in the newly created seat of Dunfermline East, where no incumbent was standing. Galloway failed to be selected for either seat, with Rhondda selecting Allan Rogers, and Dunfermline East selecting future Chancellor of the Exchequer and later Prime Minister, Gordon Brown. Standing as a candidate for a place on the Labour Party National Executive Committee in 1986, in a large field of 18 candidates, Galloway finished in 16th place.
Red yeast rice or red rice koji is a bright reddish purple fermented rice, which acquires its color from being cultivated with the mold Monascus purpureus. Red yeast rice is what is referred to as a kōji in Japanese, meaning "grain or bean overgrown with a mold culture", a food preparation tradition going back to ca. 300 BCE. In addition to its culinary use, red yeast rice is also used in Chinese herbology and Traditional Chinese medicine, possibly during the Tang dynasty around 800 CE. Red yeast rice is described in the Chinese pharmacopoeia Ben Cao Gang Mu by Li Shizhen. Use as a dietary supplement in the modern era developed in the late 1970s, after separate researchers were isolating lovastatin from Aspergillus and monacolins from Monascus, the latter being the type of fungus used to make red yeast rice. Chemical analysis soon showed that lovastatin and monacolin K were identical. Lovastatin became the patented prescription drug Mevacor, and red yeast rice went on to become a non-prescription dietary supplement in the United States and other countries. In 1998, the U.S. Food and Drug Administration (FDA) initiated action to ban dietary supplements containing red yeast rice extract, arguing that red yeast rice products containing monacolin K are identical to a prescription drug, and are thus subject to regulation as a drug.
=== Speaking === Weakness of the muscles involved in speaking may lead to dysarthria and hypophonia. Speech may be slow and slurred, or have a nasal quality. In some cases, a singing hobby or profession must be abandoned.
Sources: en.wikipedia.org
Everyone has the right to food and water, and under the Charter of Fundamental Rights of the EU "the improvement of the quality of the environment must be integrated into the policies of the Union". The Common Agricultural Policy's origins lay in ensuring that all farm workers had fair wages and everyone had food, since in 1960 a third of employment and a fifth of GDP was in agriculture, and after WW2 Europe had been on the brink of starvation. In 2020, the agricultural workforce was 4.2% of the EU total. The CAP's objectives are still to increase production, "a fair standard of living for the agricultural community", to stabilise markets and supplies, and "reasonable prices" for consumers. In 2021, the CAP was 33.1% of the entire EU budget, at €55.1 billion, however there are no requirements for subsidies to be used so that farm workers (as opposed to owners) have fair pay scales, few requirements for rural development, and minimal standards for environmental improvement.
=== Mary Conner === Mary Conner is played by Jayden Rey. Mary is D.J. and Geena's daughter. Mary is named after her deceased great-great-grandmother, Nana Mary. In Season 3, D.J. begins a new job requiring him to work long hours and often in neighboring towns. Although Geena and D.J.'s friends are checking on her throughout the day, Mary tells Darlene she is lonely. Darlene and Becky decide to have her live at the Conner house during the week without first asking D.J. He is initially angry, but relents when Mary says she wants to stay.
Their lean build and energy-conserving strategy allow a lower daily food intake than if they were more strongly muscled, yet with enough strength to commonly take bird prey as large as themselves, and occasionally larger. The success of this body style and hunting strategy is reflected in the high success of the species in densely populating a large range throughout the Americas. The flight of the American kestrel is not so dramatic and swift as more muscular falcons such as merlins and peregrines, but their efficient adaptation to a broader diet of more available smaller prey, and need for less food per day, has resulted in their greater population. In contrast to many other raptor species, the sexes differ more in plumage than in size. Males have blue-gray wings with black spots and white undersides with black barring. The back is rufous, with barring on the lower half. The belly and flanks are white with black spotting. The tail is also rufous, with a white or rufous tip and a black subterminal band. The back and wings of the female American kestrel are rufous with dark brown barring. The undersides of the females are creamy to buff with heavy brown streaking. The tail is noticeably different from the male's, being rufous in color with numerous narrow dark black bars. Juveniles exhibit coloration patterns similar to the adults'. In both sexes, the head is white with a bluish-gray top. There are also two narrow, vertical black facial markings on each side of the head, while other falcons have one.
The cell membranes of bacteria are rich in acidic phospholipids, such as phosphatidylglycerol and cardiolipin. In contrast, the outer part of the membranes of plants and mammals is mainly composed of lipids without any net charges since most of the lipids with negatively charged headgroups are principally sequestered into the inner leaflet of the plasma membranes. Thus in the case of mammalian cells, the outer surfaces of the membranes are usually made of zwitterionic phosphatidylcholine and sphingomyelin, even though a small portion of the membrane's outer surfaces contain some negatively charged gangliosides. Therefore, the hydrophobic interaction between the hydrophobic face of amphipathic antimicrobial peptides and the zwitterionic phospholipids on the cell surface of mammalian cell membranes plays a major role in the formation of peptide-cell binding. Dual polarisation interferometry has been used in vitro to study and quantify the association to headgroup, insertion into the bilayer, pore formation and eventual disruption of the membrane.
Proteins shown to interact with TMEM261 include NAAA (protein-protein interaction), QTRT1 (RNA-protein interaction),ZC4H2(DNA-protein interaction) and ZNF454(DNA-protein interaction). It has also shown to interact with APP(protein-protein interaction), ARHGEF38(protein-protein interaction) and HNRNPD(RNA-protein interaction). Additional transcription factor binding sites (DNA-protein interaction) predicted include one binding site for MEF2C a monocyte-specific enhancement factor that is involved in muscle-cell regulation particularly in the cardiovascular system and two binding sites for GATA1 which is a globin transcription factor 1 involved in erythroblast development regulation.
Sources: en.wikipedia.org
CO2 + 4 H2S + O2 → CH2O + 4 S0 + 3 H2O CO2 + H2S + O2 + H2O → CH2O + SO2–4 + 2 H+ In modern oceans, Thiomicrospira, Halothiobacillus, and Beggiatoa are primary sulfur oxidizing bacteria, and form chemosynthetic symbioses with animal hosts. The host provides metabolic substrates (e.g., CO2, O2, H2O) to the symbiont while the symbiont generates organic carbon for sustaining the metabolic activities of the host. The produced sulfate usually combines with the leached calcium ions to form gypsum, which can form widespread deposits on near mid-ocean spreading centers. Sulfur metabolizing microbes are often engaged in close symbiotic relationships with other microbes, and even animals. PSB and sulfate reducers form microbial aggregates called “pink berries” in the salt marshes of Massachusetts within which sulfur cycling occurs through the direct exchange of sulfur species. The Vestimentiferan tube worms that grow around hydrothermal vents lack a digestive tract but contain specialized organelles called trophosomes within which autotrophic, sulfide oxidizing bacteria are housed. The tube worms provide the bacteria with sulfide and the bacteria shares the fixed carbon with the worms.
== Further information == Thorium, from which 233U is bred, is roughly three to four times more abundant in the Earth's crust than uranium. The decay chain of 233U itself is part of the neptunium series, the decay chain of its grandparent 237Np. Uses for uranium-233 include the production of the medical isotopes actinium-225 and bismuth-213 which are among its daughters, low-mass nuclear reactors for space travel applications, use as an isotopic tracer, nuclear weapons research, and reactor fuel research including the thorium fuel cycle. Bismuth-213 has been investigated for use in cancer treatment. However, producing the medical isotopes from 233U practically requires separating the long-lived intermediate thorium-229. At Oak Ridge, thorium-229 is recovered from stored uranium-233 and supplied to TerraPower Isotopes for the production of actinium-225 used in cancer-treatment research.
== Stability and hydrolysis == Research into the stability of aa-tRNAs illustrates that the acyl (or ester) linkage is the most important conferring factor, as opposed to the sequence of the tRNA itself. This linkage is an ester bond that chemically binds the carboxyl group of an amino acid to the terminal 3'-OH group of its cognate tRNA. It has been discovered that the amino acid moiety of a given aa-tRNA provides for its structural integrity; the tRNA moiety dictates, for the most part, how and when the amino acid will be incorporated into a growing polypeptide chain. The different aa-tRNAs have varying pseudo-first-order rate constants for the hydrolysis of the ester bond between the amino acid and tRNA. Such observations are due to, primarily, steric effects. Steric hindrance is provided for by specific side chain groups of amino acids, which aids in inhibiting intermolecular attacks on the ester carbonyl; these intermolecular attacks are responsible for hydrolyzing the ester bond. Branched and aliphatic amino acids (valine and isoleucine) prove to generate the most stable aminoacyl-tRNAs upon their synthesis, with notably longer half lives than those that possess low hydrolytic stability (for example, proline). The steric hindrance of valine and isoleucine amino acids is generated by the methyl group on the β-carbon of the side chain. Overall, the chemical nature of the bound amino acid is responsible for determining the stability of the aa-tRNA.
OSB/0 – No added formaldehyde OSB/1 – General-purpose boards and boards for interior fitments (including furniture) for use in dry conditions OSB/2 – Load-bearing boards for use in dry conditions OSB/3 – Load-bearing boards for use in humid conditions OSB/4 – Heavy-duty load-bearing boards for use in humid conditions
== Selected publications == Armon, A., Graur, D., & Ben-Tal, N. (2001). ConSurf: An algorithmic tool for the identification of functional regions in proteins by surface-mapping of phylogenetic information. Journal of Molecular Biology, 307, 447–463. Glaser, F., Pupko, T., Paz, I., Bell, R. E., Bechor-Shental, D., Martz, E., & Ben-Tal, N. (2003). ConSurf: Identification of functional regions in proteins by surface-mapping of phylogenetic information. Bioinformatics, 19, 163–164. Pupko, T., Bell, R. E., Mayrose, I., Glaser, F., & Ben-Tal, N. (2002). Rate4Site: An algorithmic tool for the identification of functional regions in proteins by surface mapping of evolutionary determinants within their homologues. Bioinformatics, 18, S71–S77. Ashkenazy, H., Abadi, S., Martz, E., Chay, O., Mayrose, I., Pupko, T., & Ben-Tal, N. (2016). ConSurf 2016: An improved methodology to estimate and visualize evolutionary conservation in macromolecules. Nucleic Acids Research, 44, W344–W350. Rubin, M., & Ben-Tal, N. (2021). Using ConSurf to detect functionally important regions in RNA. Current Protocols, 1, e270. Ben-Tal, N., & Kessel, A. (2010). Introduction to Proteins: Structure, Function, and Motion. Ezerzer, Y., Frenkel-Pinter, M., Kolodny, R., & Ben-Tal, N. (2025). A building blocks perspective on protein emergence and evolution. Current Opinion in Structural Biology, 91, 102996. Yariv, B., Yariv, E., Kessel, A., Masrati, G., Ben Chorin, A., Martz, E., Mayrose, I., Pupko, T., & Ben-Tal, N. (2023). Using evolutionary data to make sense of macromolecules with a “face-lifted” ConSurf.
Sources: en.wikipedia.org
Karl Fischer titration is a common method, using coulometric or volumetric detection. Thermogravimetric analysis can also measure weight loss on heating. Results depend on sample handling because the dried solid can absorb moisture quickly.
The porous cake readily absorbs water vapor from air, which can reduce stability or cause collapse. Vials are sealed with stoppers and crimp seals, sometimes under vacuum or inert gas. Packaging also protects against oxygen and mechanical damage.
Collapse occurs when the product temperature rises above its collapse threshold during primary drying. The ice matrix loses structure, and the cake may shrink or melt back. Formulation excipients and freezing rate influence collapse threshold.
Primary drying removes ice by sublimation at low pressure and low shelf temperature. Secondary drying removes bound water by raising the shelf temperature, often under the same vacuum. The two stages differ in the water state being removed.