Sublimation comes up often in conversation and rarely with the context attached. Here we lay out the basics in order, then work through the practical considerations.
Updated 2025-11-09. Numbers and descriptions here follow the published literature rather than marketing material.
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.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Common name | Freeze-drying | Process removes water by sublimation under vacuum. |
| Typical primary drying shelf temperature | -40 C to -10 C | Set below the formulation's collapse temperature. |
| Typical chamber pressure | 0.05-0.3 mbar | Low pressure allows ice to sublime below its triple point. |
| Water content after drying | 0.5-3% by weight | Higher values may reduce storage stability for some materials. |
| Key thermal parameter | Collapse temperature | Measured by freeze-drying microscopy or differential scanning calorimetry. |
Although orphan disease populations are the smallest, the cost of per-patient outlays among them are the largest and are expected to increase as more people with rare diseases become eligible for subsidies – in the U.S., for example, through the Affordable Care Act.
Small molecule inhibitors have been reported for both OGT and OGA that function in cells or in vivo. OGT inhibitors result in a global decrease of O-GlcNAc while OGA inhibitors result in a global increase of O-GlcNAc; these inhibitors are not able to modulate O-GlcNAc on specific proteins. Inhibition of the hexosamine biosynthetic pathway is also able to decrease O-GlcNAc levels. For instance, glutamine analogues azaserine and 6-diazo-5-oxo-L-norleucine (DON) can inhibit GFAT, though these molecules may also non-specifically affect other pathways.
Other semi-aquatic mammals include beavers, hippopotamuses, otters and platypuses. Hippos are very large semi-aquatic mammals, and their barrel-shaped bodies have graviportal skeletal structures, adapted to carrying their enormous weight, and their specific gravity allows them to sink and move along the bottom of a river.
Nefazodone acts primarily as a potent antagonist of the serotonin 5-HT2A receptor and to a lesser extent of the serotonin 5-HT2C receptor. It also has high affinity for the α1-adrenergic receptor and serotonin 5-HT1A receptor, and relatively lower affinity for the α2-adrenergic receptor and dopamine D2 receptor. Nefazodone has low but significant affinity for the serotonin, norepinephrine, and dopamine transporters as well, and therefore acts as a weak serotonin–norepinephrine–dopamine reuptake inhibitor (SNDRI). It has low but potentially significant affinity for the histamine H1 receptor, where it is an antagonist, and hence may have some antihistamine activity. Nefazodone has negligible activity at muscarinic acetylcholine receptors, and accordingly, has no anticholinergic effects.
Ardent supporters of Duterte have been labeled as "Diehard Duterte Supporters", alternatively known as "Digong Duterte Supporters", which shares the acronym with the Davao Death Squad (DDS). This label has been applied to the 16 million people who voted for him in the 2016 presidential election. Duterte developed a reputation as a "protector" and "savior" in his hometown of Davao City as mayor of the city for more than two decades. This is despite reports of death squads in the city.
Sources: en.wikipedia.org
=== Fabrication and misrepresentation === As early as 2000, Hari was criticised by Ben Elton in the letters page of Varsity for inaccuracies including stating that only Jews can be Israeli citizens. In addition to plagiarism, Hari was found to have fabricated elements of stories. In one of the stories for which he won the 2008 Orwell Prize, he reported on atrocities in the Central African Republic, stating that French soldiers told him that "Children would bring us the severed heads of their parents and scream for help, but our orders were not to help them." However, an NGO worker who translated for Hari said that the quotation was invented and that Hari exaggerated the extent of the devastation in the CAR. In his apology after his plagiarism was exposed, Hari said that other staff of the NGO had supported his version of events. In a 2010 article about military robots, Hari falsely claimed that former Japanese prime minister Junichiro Koizumi was attacked by a factory robot and was nearly killed. Hari falsely claimed that a large globe erected for the Copenhagen climate summit was "covered with corporate logos" for McDonald's and Carlsberg, with "the Coke brand ... stamped over Africa".
It won two Academy Award-qualifying film festival awards and was nationally distributed by Conde Nast on the Them platform. In 2024, Hamer initiated a multimedia community engagement and storytelling effort on the "Queer Histories of Hawaiʻi." Funded by the Mellon Foundation, the project aims to document and memorialize gender and sexual diversity across the multicultural landscape of the Hawaiian islands. Hamer is a frequent guest on TV documentaries and news shows including Good Morning America, Nightline and The Oprah Winfrey Show. He is featured in the Barbara Walters' special Heaven and Bill Maher documentary Religulous, and has been profiled in Time magazine.
==== Neurostimulation ==== Diaphragm pacing, which involves the rhythmic application of electrical impulses to the diaphragm, has been used to treat central sleep apnea. In April 2014, the U.S. Food and Drug Administration granted pre-market approval for use of an upper airway stimulation system in people who cannot use a continuous positive airway pressure device. The Inspire Upper Airway Stimulation system is a hypoglossal nerve stimulation implant that senses respiration and applies mild electrical stimulation during inspiration, which pushes the tongue slightly forward to open the airway.
=== Congenital disorders === Congenital disorders include cystic fibrosis, pulmonary hypoplasia (an incomplete development of the lungs)congenital diaphragmatic hernia, and infant respiratory distress syndrome caused by a deficiency in lung surfactant. An azygos lobe is a congenital anatomical variation which though usually without effect can cause problems in thoracoscopic procedures.
Sources: en.wikipedia.org
Xi called for a crackdown on corruption immediately after he ascended to power, starting an anti-corruption campaign. In his inaugural speech as general secretary, Xi mentioned that fighting corruption was one of the toughest challenges for the party. A few months into his term, Xi outlined the Eight-point Regulation, listing rules intended to curb corruption and waste during official party business; it aimed at stricter discipline on the conduct of officials. Xi vowed to root out "tigers and flies", that is, high-ranking officials and ordinary party functionaries. He also launched the Party's Mass Line Education and Practice Activities, aiming CCP cadres to use mass line and instill Party discipline. The campaign lasted from 2013 to 2014. Xi's anti-corruption campaign has led to the downfall of prominent incumbent and retired CCP officials, including members of the PSC. Xi initiated cases against former CMC vice chairmen Xu Caihou and Guo Boxiong, former PSC member and security chief Zhou Yongkang and former CCP General Office director Ling Jihua. Xi has overseen significant reforms of the Central Commission for Discipline Inspection (CCDI), CCP's highest internal control institution. He and CCDI Secretary Wang Qishan further institutionalized CCDI's independence from the day-to-day operations of the CCP, improving its ability to function as a bona fide control body. Along with Wang Qishan, Xi's administration spearheaded the formation of "centrally-dispatched inspection teams".
This reaction occurs much faster at higher temperatures, and therefore higher concentrations of ethyl carbamate are found in beverages that are heated during processing, such as brandy, whiskey, and other distilled beverages. Additionally, heating after bottling either during shipping or in preparation will cause ethyl carbamate levels to rise further. The urea in wines results from the metabolism of arginine or citrulline by yeast or other organisms. The urea waste product is initially metabolised inside the yeast cell until it builds up to a certain level. At that point, it is excreted externally where it is able to react with the alcohol to create ethyl carbamate. In 1988, wine and other alcoholic beverage manufacturers in the United States agreed to control the level of ethyl carbamate in wine to less than 15 ppb (parts per billion), and in stronger alcoholic drinks to less than 125 ppb. Although the urea cannot be eliminated, it can be minimized by controlling the fertilization of grape vines, minimizing their heat exposure, using self-cloning yeast and other actions. Furthermore, some strains of yeast have been developed to help reduce ethyl carbamate during commercial production of alcoholic beverages. Another important mechanism for ethyl carbamate formation in alcoholic beverages is the reaction from cyanide as precursor, which causes comparably high levels in spirits derived from cyanogenic plants, such as rhum agricole.
National government representatives did sit on the board, but had little influence; one European representative described the environment in the mid-2010s as "highly intimidating". A 2016 funding-allocation analysis of a sample of Gavi grants found that just over half the money went to purchasing drugs, equipment, supplies, and facilities (and 3% on bonuses and incentive pay). These are short-term funding activities which the WHO does not consider HSS. The proportions were higher in less-developed healthcare systems. There was no spending on operational research, improving use of existing resources, or developing national drug and vaccine policies. In some grants, HSS funds were mostly spent on day-to-day operational costs, with no exit plan for the funding. Gavi subsequently (before 2018) shifted HSS aid to focus more on sustainability and the principles of the Paris Declaration for Aid Effectiveness.
Sources: en.wikipedia.org
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.
Freezing determines ice crystal size, pore structure, and the concentration of solutes in remaining liquid. Faster freezing generally creates smaller ice crystals and a denser dried matrix. These features affect drying rate and reconstitution behavior.
Lyophilization reduces water content but usually leaves a small amount of water in the dried material. Some water remains bound to solids or trapped in the dried matrix. Very low water targets can require extended secondary drying, which may alter product stability.
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.