A practical reference on Container closure: what it is, how it behaves, what the literature reports, and where the honest uncertainties sit.
Reviewed 2025-10-01. Anything still debated is marked as such rather than presented as settled.
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.
Quality assessment of a lyophilized product includes cake appearance, residual moisture, reconstitution time, and container closure integrity. A uniform, porous cake suggests that freezing and drying stayed within the formulation's design space. Cracks, shrinkage, meltback, or a glassy film can indicate thermal abuse or a formulation problem. Analysts also test for subvisible particles and sterility when the product requires those specifications. Visual inspection alone cannot confirm biological activity or chemical stability, so it is combined with analytical methods.
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.
| 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. |
Because the molecular weight of endotoxins is usually over 10 kD, ultrafiltration can sometimes be used to perform as a size based separation. Due to the high variability of endotoxin size, it can be difficult to select the correct membrane, hence this method is best used only when all endotoxins present are larger than 300,000 Da. Commercially available ultra filters have been shown to remove pyrogens to a level below 0.001 EU/ml.
After the malaise of the late 1920s and early 1930, the 1933 season proved a turning point in morale despite no finals entries for the entire 1930s. Essendon saw the debut of the player regarded as one of the game's greatest-ever players, Dick Reynolds. His impact was immediate. He won his first Brownlow Medal aged 19. His record of three Brownlow victories (1934, 1937, 1938), equalled Fitzroy's Haydn Bunton, Sr (1931, 1932, 1935), and later equalled by Bob Skilton (1959, 1963, 1968), and Ian Stewart (1965, 1966, 1971). Reynolds was appointed coach, jointly with Harry Hunter, in 1939 while still a player. A year later, he became the sole coach and led the side into the finals in 1940 for the first time since 1926, finishing third. Melbourne defeated Essendon by 5 points in the preliminary final and went on to win the premiership. The Essendon Football Club adopted the nickname The Bombers in April 1940. The 1941 season culminated in Essendon's first grand final appearance since 1923, but the side again lowered its colours to Melbourne. While Australia had entered World War II – located primarily in Europe and Africa – in 1939, the Pacific Theatre opened in December 1941. Australian sports competition was considerably weakened, with Geelong being forced to pull out of the competition due to petrol rationing. Attendances at games also declined dramatically, while some clubs had to move from their normal grounds due to them being used for military purposes. Many players were lost to football due to their military service.
Racial disparities have been a prominent and contentious aspect of the war on drugs in the US. In 1957, a belief at the time about drug use was summarized by journalist Max Lerner in his work, America as a Civilization: "As a case in point we may take the known fact of the prevalence of reefer and dope addiction in Negro areas. This is essentially explained in terms of poverty, slum living, and broken families, yet it would be easy to show the lack of drug addiction among other ethnic groups where the same conditions apply." The Anti-Drug Abuse Act of 1986 created a 100:1 sentencing disparity in the US for the trafficking or possession of crack when compared to penalties for trafficking of powder cocaine. The bill had been widely criticized as discriminatory against minorities, mostly blacks, who were more likely to use crack than powder cocaine. In 1994, studying the effects of the 100:1 sentencing ratio, the United States Sentencing Commission (USSC) found that nearly two-thirds of crack users were white or Hispanic, while nearly 85% of those convicted for possession were black, with similar numbers for trafficking. Powder cocaine offenders were more equally divided across race. The USSC noted that these disparities resulted in African Americans serving longer prison sentences than other ethnicities. In a 1995 report to Congress, the USSC recommended against the 100:1 sentencing ratio. In 2010, the 100:1 sentencing ratio was reduced to 18:1. Other studies indicated similarly dramatic racial differences in enforcement and sentencing.
=== White Sands trackway and peopling of North America === The earliest compelling evidence for human habitation of the Americas comes from the Clovis complex, between 11,050 and 10,800 14C yr B.P. However, a series of human tracks were identified at White Sands National Park, New Mexico, which have been dated contentiously dated to between 23,000 and 21,000 years ago - during the Last Glacial Maximum. Alongside anatomically modern humans, the trackway shows impressions created by a Columbian mammoth and a giant ground sloth. The upper biostratigraphic limit for when the impressions were made could therefore be determined by consideration of the extinction dates of mammoths and ground sloths. More precise dates were able to be gained via radiocarbon dating of ditch grass (ruppia cirrhosa) embedded in the prints. These seeds produced a date of 23,000-21,000 years ago. However, 14C dates are not infallible, and this remains a topic of debate. A recent counterproposal posits that the trackways were, in fact, created by the Clovis culture and the pre-existing proposed dates of first habitation should not be moved. False dates may have been produced as older strata containing the seeds could have been eroded and displaced onto the damp clay, before being impressed in by footsteps. Alternatively, aquatic plants like ditch grass reflect the 14C levels in their environment when living, if 14C was deficient in the habitat, this could imply a false date.
Sources: en.wikipedia.org
==== F ==== Fenalår – in Norway, salted, dried and cured leg of lamb. Curing time is normally about three months, but the "fenalår" may be matured for a year or more. The meat is dark red to brownish, with a pronounced taste of mutton. Fenalår is a very popular dish in Norway, and is often served with other preserved food at a Christmas buffet or at Norwegian Constitution Day. Normally the meat is served as thin slices, but it is also common – at informal gatherings – to send the leg around the table with a sharp, stubby knife. The guests then slice the leg themselves. Thus, in western Norway "fenalår" is called "spikkekjøtt", literally "whittle-meat", but this name may also origin from the word "speke", "to cure".
==== Photolithography ==== Ultraviolet radiation is used for very fine resolution photolithography, a procedure wherein a chemical called a photoresist is exposed to UV radiation that has passed through a mask. The exposure causes chemical reactions to occur in the photoresist. After removal of unwanted photoresist, a pattern determined by the mask remains on the sample. Steps may then be taken to "etch" away, deposit on or otherwise modify areas of the sample where no photoresist remains. Photolithography is used in the manufacture of semiconductors, integrated circuit components, and printed circuit boards. Photolithography processes used to fabricate electronic integrated circuits presently use 193 nm UV and are experimentally using 13.5 nm UV for extreme ultraviolet lithography.
=== Neural sources === In the hypothalamus, oxytocin is made in magnocellular neurosecretory cells of the supraoptic and paraventricular nuclei, and is stored in Herring bodies at the axon terminals in the posterior pituitary. It is then released into the blood from the posterior lobe (neurohypophysis) of the pituitary gland. These axons (likely, but dendrites have not been ruled out) have collaterals that innervate neurons in the nucleus accumbens, a brain structure where oxytocin receptors are expressed. The endocrine effects of hormonal oxytocin, and the cognitive or behavioral effects of oxytocin neuropeptides are thought to be coordinated through its common release through these collaterals. Oxytocin is also produced by some neurons in the paraventricular nucleus that project to other parts of the brain and to the spinal cord. Depending on the species, oxytocin receptor-expressing cells are located in other areas, including the amygdala and bed nucleus of the stria terminalis. In the pituitary gland, oxytocin is packaged in large, dense-core vesicles, where it is bound to neurophysin I as shown in the inset of the figure; neurophysin is a large peptide fragment of the larger precursor protein molecule from which oxytocin is derived by enzymatic cleavage. The electrical activity of the oxytocin cells in the hypothalamus regulates the secretion of oxytocin from the neurosecretory nerve endings.
Magnetic nanoparticle drug delivery is the use of external or internal magnets to increase the accumulation of therapeutic elements contained in nanoparticles to fight pathologies in specific parts of the body. It has been applied in cancer treatments, cardiovascular diseases, and diabetes. Scientific researches revealed that magnetic drug delivery can be made increasingly useful in clinical settings.
Miguel Angel Ondetti (May 14, 1930 – August 23, 2004) was an Argentine-born American chemist who first synthesized captopril, the first ACE inhibitor that was used to treat heart disease. With his co-worker, David Cushman, he won the 1999 Lasker Award, with David Cushman, for: "developing an innovative approach to drug design based on protein structure and using it to create the ACE inhibitors, powerful oral agents for the treatment of high blood pressure, heart failure, and diabetic kidney disease". Ondetti was born and raised in Buenos Aires and received a PhD in chemistry from the University of Buenos Aires, in his hometown, in 1957. In 1960 he moved to The Squibb Institute for Medical Research in New Jersey where he researched and developed Captopril in 1975.
Sources: en.wikipedia.org
== External links == "Dihydrocodeine". Drug Information Portal. U.S. National Library of Medicine. Archived from the original on 17 September 2021. Media related to Dihydrocodeine at Wikimedia Commons
In one transient hot-wire study of monolithic silica aerogel, Cohen and Glicksman reported that the thermal conductivity decreased from 9.3 mW·m−1·K−1 (0.0093 W·m−1·K−1) at 1 atm to 3.2 mW·m−1·K−1 (0.0032 W·m−1·K−1) at 0.1 atm; the same aerogel in granular form had a thermal conductivity of 15.0 mW·m−1·K−1 at ambient gas pressure under modest compression. Its melting point is 1,473 K (1,200 °C; 2,192 °F). Until 2011, silica aerogel held 15 entries in Guinness World Records for material properties, including best insulator and lowest-density solid, though it was ousted from the latter title by the even lighter materials aerographite in 2012 and then aerographene in 2013.
To cataplerotically remove oxaloacetate from the citric cycle, malate can be transported from the mitochondrion into the cytoplasm, decreasing the amount of oxaloacetate that can be regenerated. Furthermore, citric acid intermediates are constantly used to form a variety of substances such as the purines, pyrimidines and porphyrins.
The Vaal uprising was a period of popular revolt in black townships in apartheid-era South Africa, beginning in the Vaal Triangle on 3 September 1984. Sometimes known as the township revolt and driven both by local grievances and by opposition to apartheid, the uprising lasted two years and affected most regions of the country. The National Party-led government under P. W. Botha failed to curb the violence until after it imposed a national state of emergency in June 1986. The uprising began on 3 September in the Vaal Triangle, an industrial region south of Johannesburg, where the local Vaal Civic Association had organised a stay-away to protest rent increases. In the deadliest day of protesting since the 1976 Soweto uprising, there were an estimated 300 injuries and 29 fatalities, some of whom were black local councillors executed by protestors. Over the next year, civic associations and student organisations carried the riots to other areas of the country. From late 1984, in what marked a new phase of united mass action in opposition politics, protestors received support from the emerging trade union movement, including from the Federation of South African Trade Unions. A primary target of the violence in townships were black local councillors, newly empowered by the Black Local Authorities Act. Also targeted were others viewed as collaborators of the apartheid system, such as black policemen, informants, and even school principals.
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.
Many dried cakes are hygroscopic and can adsorb water during storage or handling. Absorbed moisture may lower the glass transition temperature and promote chemical reactions. Sealed packaging and controlled humidity reduce this risk.