cake collapse 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 2026-01-28. Numbers and descriptions here follow the published literature rather than marketing material.
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.
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.
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.
Quality control for lyophilized products focuses on appearance, moisture level, reconstitution time, and structural integrity. A cake should be uniform, intact, and free of meltback or collapse. Moisture level is measured by Karl Fischer titration or thermogravimetric analysis. Reconstitution time reflects pore structure and formulation. Visual inspection and vial integrity checks detect cracks, stopper defects, or particulate matter. These checks are often performed on samples from each batch. They help confirm that the drying cycle performed as intended.
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.
| Property | Value | Notes |
|---|---|---|
| Cake appearance | Uniform porous plug | Cracks, shrinkage, or meltback suggest process deviation. |
| Reconstitution time | 10 seconds to 5 minutes | Depends on cake structure, diluent, and agitation. |
| Typical storage humidity | Below 60% relative humidity | Lower humidity limits moisture uptake by hygroscopic cakes. |
| Container closure | Glass vial, elastomer stopper, crimp seal | Seal integrity limits moisture and oxygen ingress. |
| Common moisture test | Karl Fischer titration | Measures residual water content in the dried solid. |
Reconstitution involves adding a suitable diluent, often sterile water or a buffer, to the dried cake. Gentle swirling or inversion helps dissolve the material without creating excessive foam. The time required for complete dissolution can range from seconds to several minutes and depends on the cake structure and the diluent. Improper reconstitution, such as vigorous shaking or using the wrong diluent, can cause protein aggregation or loss of activity. After reconstitution, the product may have a limited shelf life and should be used according to its labeling.
Lyophilized products are typically hygroscopic and require protection from moisture during storage. Manufacturers seal them in glass vials, often under vacuum or an inert gas such as nitrogen. The container closure system, including the stopper and crimp seal, must prevent water vapor ingress. Storage temperature varies from controlled room temperature to refrigerated or frozen conditions, depending on the formulation. Humidity-controlled environments are essential because even brief exposure to ambient air can degrade the product.
Stability of a lyophilized product depends on its glass transition temperature, the temperature at which the amorphous cake transitions from a glassy to a rubbery state. Storage below this temperature minimizes molecular mobility and slows chemical degradation. If the storage temperature exceeds the glass transition temperature, the cake may collapse, shrink, or become sticky. Accelerated stability studies at elevated temperatures and humidity help predict shelf life, but they do not always reflect real-time behavior. Residual moisture content also plays a critical role in long-term stability.
Regulatory expectations for lyophilized products focus on consistent manufacture and documented stability. Batches are often monitored for moisture, appearance, potency, and sterility where applicable. Process parameters such as shelf temperature, chamber pressure, and drying time are recorded and controlled within validated ranges. Open questions remain about how best to predict long-term stability from short accelerated studies, especially for complex biologics. Variations in freezing rate and ice crystal size can produce differences that are not always visible but may affect performance.
After drying, a lyophilized product is usually sealed under vacuum or an inert gas to limit moisture uptake. Residual water content is measured because small changes can alter chemical stability and cake appearance. Storage temperature depends on the material; many biological products are kept at 2–8 °C, while some require −20 °C or colder. Exposure to ambient humidity during handling can cause the porous solid to absorb water and collapse. Container closures and stoppers are therefore selected for low moisture transmission and compatibility.
Quality control for lyophilized materials includes visual inspection of the cake, measurement of residual moisture, and tests for reconstitution time. An acceptable cake is typically uniform and may be slightly porous; shrinkage, meltback, or cracks can indicate process deviations. Analytical methods such as Karl Fischer titration, thermogravimetric analysis, and near-infrared spectroscopy quantify water content. Reconstitution time is recorded because a very slow or incomplete dissolution can signal collapse or aggregation. Stability studies compare samples stored under defined temperature and humidity conditions over months or years.
Quality control for freeze-dried lots combines visual inspection with instrumental tests. Cake appearance, color, and shrinkage are recorded against a reference, while residual moisture is measured by Karl Fischer titration or loss on drying. Thermal analysis can reveal phase transitions and crystallization events, and X-ray diffraction distinguishes amorphous from crystalline solids. Microbiological tests and container closure integrity checks are also routine for sterile products. Analytical methods must be validated for the matrix, because excipients and low moisture can affect accuracy. Open questions include how best to predict long-term stability from short-term data.
Lyophilized solids are often hygroscopic, so handling occurs in controlled low-humidity areas or glove boxes when the material is exposed. Vials remain sealed with elastomeric stoppers and aluminum crimps until use, because airborne moisture can raise residual water and shorten shelf life. The porous cake is fragile and may crack, shrink, or powder during transport. Personnel typically avoid repeated warming and cooling of sealed units, which can draw moisture through closures. These practices aim to preserve the low water content achieved during drying.
Storage conditions depend on the formulation and the intended shelf life. Many pharmaceutical and biological freeze-dried products are kept at 2–8 °C, while some stable foods and reagents tolerate room temperature. Others require −20 °C or colder to slow chemical degradation or aggregation. Protection from light and oxygen is common because oxidation can continue in the dry state. Stability studies usually monitor potency, appearance, moisture, and reconstitution time over months or years. Predictions from accelerated studies are useful but may not fully capture real-time changes.
Quality control for lyophilized products includes appearance, cake structure, reconstitution time, pH, residual moisture, and potency. Residual moisture is a key attribute because excess water can reduce stability, while excessively low moisture may cause structural changes or aggregation in some systems. Stability studies compare real-time and accelerated conditions to estimate shelf life. Analytical methods must be validated for the specific matrix, container, and moisture range. Sterility and container integrity are also monitored for sterile products.
Handling practices aim to prevent moisture ingress and mechanical damage. Vials should remain stoppered and crimped until use, and reconstitution should follow the labeled diluent and volume. Shipping may involve temperature-controlled containers and desiccants, but direct contact between desiccant and product is avoided. Regulatory guidance expects documented storage conditions, excursion assessments, and stability commitments. Open questions remain about how best to predict long-term stability from short accelerated studies for every formulation class.
After lyophilization, the product is usually a porous cake or powder with a large internal surface area. This structure can absorb moisture quickly if exposed to humid air, so vials are sealed under vacuum or an inert gas. Moisture uptake may lower the glass transition temperature of the dried matrix and accelerate chemical or physical degradation. Storage conditions therefore depend on the formulation, container, and intended shelf life. Some products remain stable at room temperature, while others require refrigeration or freezing.
Egypt (c. 1600–1500 BCE): The Edwin Smith Papyrus (c. 1600 BCE), one of the earliest known surgical texts, describes wound treatments involving cleansing, bandaging, and poultice-like applications made with honey and animal fats. The Ebers Papyrus (c. 1550 BCE) contains numerous recipes for poultices combining lint, honey, and grease, applied to wounds and inflammations. Mesopotamia (c. 2200 BCE): Sumerian clay tablets describe wound washing, herbal dressings, and poultices using ingredients such as milk and beer. India (c. 200 CE): The Sushruta Samhita, a foundational Sanskrit medical encyclopedia, prescribed poultices made of herbs, ghee, and oils for in many contexts including for cleansing wounds and promoting healing. Greece and Rome (c. 400 BCE - 200 CE): Hippocrates (c. 460–370 BCE) recommended cleansing wounds with wine or vinegar, then applying poultices of honey, oil, and wine. In both Greece and Rome, poultices of wool, linen, and crushed plants were commonly used for inflammations and injuries. Later practices During the Middle Ages and Renaissance, poultices made from flour, linseed, mustard, bran, herbs, or bread were widely used in Europe. They were often applied hot to "draw out" infection, relieve swelling, or soften abscesses. Poultices subsequently remained a standard remedy in both civilian and military medicine.
==== Young's modulus of elasticity ==== Young's modulus quantifies the elasticity of the polymer. It is defined, for small strains, as the ratio of rate of change of stress to strain. Like tensile strength, this is highly relevant in polymer applications involving the physical properties of polymers, such as rubber bands. The modulus is strongly dependent on temperature. Viscoelasticity describes a complex time-dependent elastic response, which will exhibit hysteresis in the stress-strain curve when the load is removed. Dynamic mechanical analysis or DMA measures this complex modulus by oscillating the load and measuring the resulting strain as a function of time.
== Pets == Wheatgrass is also cultivated for feeding to pet cats. Wheatgrass, along with shoots of other common grains such as oats, rye and barley, is sold for this purpose, including under the name cat grass. Many cats enjoy eating grass and wheatgrass is considered safe and healthy for them. It may provide nutrients and improve digestion by adding fiber to the diet. Eating wheatgrass may also provide mental stimulation. However, it is recommended to limit the quantity allowed, to avoid indigestion.
At this point, it was known that organic molecules could be formed from inorganic starting materials, as Friedrich Wöhler had described the Wöhler synthesis of urea from ammonium cyanate in 1828. Several other early seminal works in the field of organic synthesis followed, including Alexander Butlerov's synthesis of sugars from formaldehyde and Adolph Strecker's synthesis of the amino acid alanine from acetaldehyde, ammonia, and hydrogen cyanide. In 1913, Walther Löb synthesized amino acids by exposing formamide to silent electric discharge, so scientists were beginning to produce the building blocks of life from simpler molecules, but these were not intended to simulate any prebiotic scheme or even considered relevant to origin of life questions. But the scientific literature of the early 20th century contained speculations on the origin of life. In 1903, physicist Svante Arrhenius hypothesized that the first microscopic forms of life, driven by the radiation pressure of stars, could have arrived on Earth from space in the panspermia hypothesis. In the 1920s, Leonard Troland wrote about a primordial enzyme that could have formed by chance in the primitive ocean and catalyzed reactions, and Hermann J. Muller suggested that the formation of a gene with catalytic and autoreplicative properties could have set evolution in motion. Around the same time, Alexander Oparin's and J. B. S.
== Early life == Lovett-Murray has Indigenous Australian heritage and his tribal ancestry can be traced to the Wamba-Wamba and Gunditjmara. He began his football in Victoria playing country football with Heywood and the North Ballarat Rebels.
Sources: en.wikipedia.org
==== Australian cultures ==== Some Aboriginal Australian groups use circumcision as a test of bravery and self-control as a part of a rite of passage into manhood, which results in full societal and ceremonial membership. It may be accompanied by body scarification and the removal of teeth, and may be followed by penile subincision. Circumcision is one of many trials and ceremonies required before a youth is considered to have become knowledgeable enough to maintain and pass on the cultural traditions. During these trials, the maturing youth bonds in solidarity with the men. Circumcision is also strongly associated with a man's family, and it is part of the process required to prepare a man to take a wife and produce his own family.
==== Peripheral reticulum ==== Some chloroplasts contain a structure called the chloroplast peripheral reticulum. It is often found in the chloroplasts of C4 plants, though it has also been found in some C3 angiosperms, and even some gymnosperms. The chloroplast peripheral reticulum consists of a maze of membranous tubes and vesicles continuous with the inner chloroplast membrane that extends into the internal stromal fluid of the chloroplast. Its purpose is thought to be to increase the chloroplast's surface area for cross-membrane transport between its stroma and the cell cytoplasm. The small vesicles sometimes observed may serve as transport vesicles to shuttle stuff between the thylakoids and intermembrane space.
=== Complications === Complications of smallpox arise most commonly in the respiratory system and range from simple bronchitis to fatal pneumonia. Respiratory complications tend to develop on about the eighth day of the illness and can be either viral or bacterial in origin. Secondary bacterial infection of the skin is a relatively uncommon complication of smallpox. When this occurs, the fever usually remains elevated. Other complications include encephalitis (1 in 500 patients), which is more common in adults and may cause temporary disability; permanent pitted scars, most notably on the face; and complications involving the eyes (2% of all cases). Pustules can form on the eyelid, conjunctiva, and cornea, leading to complications such as conjunctivitis, keratitis, corneal ulcer, iritis, iridocyclitis, and atrophy of the optic nerve. Blindness results in approximately 35–40% of eyes affected with keratitis and corneal ulcer. Hemorrhagic smallpox can cause subconjunctival and retinal hemorrhages. In 2–5% of young children with smallpox, virions reach the joints and bone, causing osteomyelitis variolosa. Bony lesions are symmetrical, most common in the elbows, legs, and characteristically cause separation of the epiphysis and marked periosteal reactions. Swollen joints limit movement, and arthritis may lead to limb deformities, ankylosis, malformed bones, flail joints, and stubby fingers. Between 65 and 80% of survivors conserve indelible white scars.
=== Optical activity === Whether in water or the solid form, d-(+)-glucose is dextrorotatory, meaning it will rotate the direction of polarized light clockwise as seen looking toward the light source. The effect is due to the chirality of the molecules, and indeed the mirror-image isomer, l-(−)-glucose, is levorotatory (rotates polarized light counterclockwise) by the same amount. The strength of the effect is different for each of the five tautomers. The d- prefix does not refer directly to the optical properties of the compound. It indicates that the C-5 chiral center has the same handedness as that of d-glyceraldehyde (which was so labeled because it is dextrorotatory). The fact that d-glucose is dextrorotatory is a combined effect of its four chiral centers, not just of C-5; some of the other d-aldohexoses are levorotatory. The conversion between the two anomers can be observed in a polarimeter since pure α-d-glucose has a specific rotation angle of +112.2° mL/(dm·g), pure β-d-glucose of +17.5° mL/(dm·g). When equilibrium has been reached after a certain time due to mutarotation, the angle of rotation is +52.7° mL/(dm·g). By adding acid or base, this transformation is much accelerated. The equilibration takes place via the open-chain aldehyde form.
Tetrodotoxin (TTX) is a potent neurotoxin. Its name derives from Tetraodontiformes, an order that includes pufferfish, porcupinefish, ocean sunfish, and triggerfish; several of these species carry the toxin. Although tetrodotoxin was discovered in these fish, it is found in several other animals (e.g., in blue-ringed octopuses, rough-skinned newts, and moon snails). It is also produced by certain infectious or symbiotic bacteria like Pseudoalteromonas, Pseudomonas, and Vibrio as well as other species found in symbiotic relationships with animals and plants. Although it produces thousands of intoxications annually and several deaths, it has shown efficacy for the treatment of cancer-related pain in phase II and III clinical trials. Tetrodotoxin is a sodium channel blocker. It inhibits the firing of action potentials in neurons by binding to the voltage-gated sodium channels in nerve cell membranes and blocking the passage of sodium ions (responsible for the rising phase of an action potential) into the neuron. This prevents the nervous system from carrying messages and thus muscles from contracting in response to nervous stimulation. Its mechanism of action – selective blocking of the sodium channel – was shown definitively in 1964 by Toshio Narahashi and John W. Moore at Duke University, using the sucrose gap voltage clamp technique.
Sources: en.wikipedia.org
The decomposition of L-tyrosine (syn. para-hydroxyphenylalanine) begins with an α-ketoglutarate dependent transamination through the tyrosine transaminase to para-hydroxyphenylpyruvate. The positional description para, abbreviated p, mean that the hydroxyl group and side chain on the phenyl ring are across from each other (see the illustration below). The next oxidation step catalyzes by p-hydroxyphenylpyruvate dioxygenase and splitting off CO2 homogentisate (2,5-dihydroxyphenyl-1-acetate). In order to split the aromatic ring of homogentisate, a further dioxygenase, homogentisate 1,2-dioxygenase is required. Thereby, through the incorporation of a further O2 molecule, maleylacetoacetate is created. Fumarylacetoacetate is created by maleylacetoacetate cis-trans-isomerase through rotation of the carboxyl group created from the hydroxyl group via oxidation. This cis-trans-isomerase contains glutathione as a coenzyme. Fumarylacetoacetate is finally split by the enzyme fumarylacetoacetate hydrolase through the addition of a water molecule. Thereby fumarate (also a metabolite of the citric acid cycle) and acetoacetate (3-ketobutyroate) are liberated. Acetoacetate is a ketone body, which is activated with succinyl-CoA, and thereafter it can be converted into acetyl-CoA, which in turn can be oxidized by the citric acid cycle or be used for fatty acid synthesis. Phloretic acid is also a urinary metabolite of tyrosine in rats.
Transport phenomena Aerodynamics Applied mechanics Bernoulli's principle Communicating vessels Computational fluid dynamics Compressor map Secondary flow Different types of boundary conditions in fluid dynamics Fluid–structure interaction Immersed boundary method Stochastic Eulerian Lagrangian method Stokesian dynamics Smoothed-particle hydrodynamics
== Penalties == Following the CAS's guilty verdict on 12 January 2016, all affected players were formally named and began their suspensions immediately. The two-year ineligibility period was backdated to 31 March 2015, and credit was taken for provisional suspensions served during the 2014/15 offseason. This meant that most players were suspended until November 2016, and missed the entire 2016 season. Alwyn Davey and Leroy Jetta, who had served shorter provisional suspensions, were suspended until February 2017, which saw them miss the end of the 2015/16 NTFL season, the 2016 winter season and most of the 2016/17 NTFL season. Under the terms of the ban players were not permitted to:
Angelica keiskei, commonly known under the Japanese name of ashitaba (アシタバ or 明日葉), literally "tomorrow's leaf", is a species of flowering plant in the carrot family. It is native to Japan, where it is found on the Pacific Coast. It is native to the area of the Bōsō Peninsula, Miura Peninsula, Izu Peninsula, and the Izu Islands. It has been widely cultivated outside its natural range.
==== 2010 kimchi ingredient price crisis ==== Due to heavy rainfall shortening the harvesting time for cabbage and other main ingredients for kimchi in 2010, the price of kimchi ingredients and kimchi itself rose greatly. Korean and international newspapers described the rise in prices as a national crisis. Some restaurants stopped offering kimchi as a free side dish, which The New York Times compared to an American hamburger restaurant no longer offering free ketchup. In response to the kimchi price crisis, the South Korean government announced the temporary reduction of tariffs on imported cabbage to coincide with the kimjang season.
Sources: en.wikipedia.org
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.
Cake collapse usually means the product became too warm during the drying cycle. The dried matrix loses porosity and may appear shrunken or glassy. Collapse can slow reconstitution and may signal altered stability, though not every collapsed cake fails specifications.
Karl Fischer titration is a common method for measuring residual water in lyophilized solids. Loss on drying and thermogravimetric analysis are also used in some settings. The chosen method should be validated for the specific formulation and moisture range.
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.