A practical reference on lyoprotectant: what it is, how it behaves, what the literature reports, and where the honest uncertainties sit.
Reviewed 2026-03-08. Anything still debated is marked as such rather than presented as settled.
Lyophilization, also known as freeze-drying, is a process that removes water from a material by freezing it and then reducing pressure to allow ice to sublimate directly into vapor. The method begins with a freezing step that solidifies the water content. Next, primary drying lowers the pressure below the triple point of water, enabling sublimation without passing through a liquid phase. A final secondary drying step removes bound water through desorption. This sequence produces a dry, porous cake that can be reconstituted later.
The process relies on the phase diagram of water, where the triple point marks the conditions at which ice, liquid water, and vapor coexist. By maintaining pressure below this point, typically around 0.01 to 0.1 millibar, sublimation becomes the dominant mechanism. Formulations often include excipients such as sugars or polymers that act as lyoprotectants and bulking agents. These additives help preserve the structure of the active ingredient and prevent collapse during drying. The choice of excipient and freezing rate influences the final cake morphology and stability.
Industries use lyophilization for pharmaceuticals, biological products, and food preservation. In the pharmaceutical sector, it extends the shelf life of injectable drugs, vaccines, and proteins that are unstable in aqueous solution. Food manufacturers apply freeze-drying to coffee, fruits, and ready meals to retain flavor and texture. The process is energy-intensive and requires specialized equipment, which limits its use to high-value products. Ongoing research examines how formulation and process parameters affect the quality of the final dried product.
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 name | Freeze-drying | Lyophilization is the technical synonym. |
| Typical chamber pressure | 0.01–0.1 mbar | Below the triple point of water. |
| Primary drying temperature | −40 to −10 °C | Depends on formulation and equipment. |
| Residual moisture | 1–5% | Target for many pharmaceutical products. |
| Typical equipment | Vacuum freeze-dryer | Includes drying chamber and condenser. |
In practice, lyophilization is slower and more energy intensive than simple drying. Cycle times can range from hours to several days depending on load, container, and formulation. Amorphous materials may require excipients that help preserve structure during freezing and drying. The method is widely used for biological materials, pharmaceuticals, and foods where heat drying would cause unacceptable change. Open questions remain about scaling cycles between laboratory and production equipment, and this gap affects technology transfer.
Lyophilization removes water by freezing a material and then lowering pressure so ice changes directly to vapor. The process relies on sublimation, the phase transition from solid to gas without an intermediate liquid state. Because the material remains frozen during primary drying, the structure often stays porous. This porous matrix can rehydrate quickly when water is added back. The low pressure also allows vapor to leave the solid matrix without boiling.
A typical cycle begins with freezing, which fixes the material into a solid and determines ice crystal size. Primary drying then raises heat under vacuum so ice sublimes, often near or below the collapse temperature of the formulation. Secondary drying removes bound water that remains after ice is gone, usually by gently warming the product. Each stage balances heat input against pressure to avoid melting or structural damage. Temperature probes and pressure sensors guide the transition between stages.
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.
Despite not being encoded by the genetic code as proteinogenic amino acids, some non-standard amino acids are nevertheless found in proteins. These are formed by post-translational modification of the side chains of standard amino acids present in the target protein. These modifications are often essential for the function or regulation of a protein; for example, in γ-carboxyglutamate the carboxylation of glutamate allows for better binding of calcium cations, and in hydroxyproline the hydroxylation of proline is critical for maintaining connective tissues. Another example is the formation of hypusine in the translation initiation factor EIF5A, through modification of a lysine residue. Such modifications can also determine the localization of the protein, for example, the addition of long hydrophobic groups can cause a protein to bind to a phospholipid membrane.
Δh = The head loss due to pipe friction over the given length of pipe (SI units: m); g = The local acceleration due to gravity (m/s2). It is useful to present head loss per length of pipe (dimensionless):
== ISO 8000 – ISO 8999 == ISO 8000 Data quality ISO 8002:1986 Mechanical vibrations – Land vehicles – Method for reporting measured data ISO 8015:2011 Geometrical product specifications (GPS) – Fundamentals – Concepts, principles and rules ISO 8041:2005 Human response to vibration - Measuring instrumentation ISO 8041-1:2017 Part 1: General purpose vibration meters ISO 8042:1988 Shock and vibration measurements – Characteristics to be specified for seismic pick-ups ISO 8044:2015 Corrosion of metals and alloys – Basic terms and definitions ISO 8048:1984 Technical drawings – Construction drawings – Representation of views, sections and cuts ISO 8049:2016 Ferronickel shot - Sampling for analysis ISO 8050:1988 Ferronickel ingots or pieces - Sampling for analysis ISO 8062 Geometrical product specifications (GPS) - Dimensional and geometrical tolerances for moulded parts ISO 8062-1:2007 Part 1: Vocabulary ISO/TS 8062-2:2013 Part 2: Rules ISO 8062-3:2007 Part 3: General dimensional and geometrical tolerances and machining allowances for castings ISO 8062-4:2017 Part 4: General tolerances for castings using profile tolerancing in a general datum system ISO 8063 Information processing – Data interchange on 6,30 mm (0.25 in) wide magnetic tape cartridge using IMFM recording at 252 ftpmm (6 400 ftpi) ISO 8063-1:1986 Part 1: Mechanical, physical and magnetic properties ISO 8063-2:1986 Part 2: Track format and method of recording for data interchange in start/stop mode ISO 8064:1985 Information processing – Reels for 12,7 mm (0,5 in) wide magnetic tapes – Sizes 16, 18 and 22 ISO/IEC 8072:1996 Information technology – Open systems interconnection – Transport service definition ISO/IEC 8073:1997 Information technology – Open Systems Interconnection – Protocol for providing the connection-mode transport service ISO 8088:1994 Equipment for olive cultivation and olive oil production – Vocabulary ISO 8090:1990 Cycles – Terminology ISO 8107:1993 Nuclear power plants - Maintainability - Terminology ISO 8109:1990 Banking and related financial services – Securities – Format of Eurobonds ISO 8114:1990 Textile machinery and accessories – Spindles for ring-spinning and doubling machines – List of equivalent terms ISO 8116 Textile machinery and accessories – Beams for winding ISO 8116-1:1995 Part 1: General vocabulary ISO 8119 Textile machinery and accessories – Needles for knitting machines – Terminology ISO 8119-1:1989 Part 1: Latch-type needles ISO 8119-2:1989 Part 2: Bearded needles ISO 8119-3:1992 Part 3: Compound needles ISO/IEC 81346: Industrial systems, installations and equipment and industrial products – structuring principles and reference designations ISO 8147:1995 Shipbuilding and marine structures – Derrick rigs and component parts – Vocabulary ISO 8152:1984 Earth-moving machinery – Operation and maintenance – Training of mechanics ISO 8153 Aerospace fluid systems and components – Vocabulary ISO 8153-1:2009 Part 1: Hose assemblies ISO 8157:2015 Fertilizers and soil conditioners – Vocabulary ISO 8159:1987 Textiles – Morphology of fibres and yarns – Vocabulary ISO 8160:1987 Textiles – Textured filament yarns – Vocabulary ISO 8178 Reciprocating internal combustion engines - Exhaust emission measurement ISO 8180 Ductile iron pipelines – Polyethylene sleeving for site application ISO 8199:2005 Water quality – General guidance on the enumeration of micro-organisms by culture ISO/IEC 8208:2000 Information technology – Data communications – X.25 Packet Layer Protocol for Data Terminal Equipment ISO/IEC 8211:1994 Information technology - Specification for a data descriptive file for information interchange ISO 8217:2017 Petroleum products - Fuels (class F) - Specifications of marine fuels ISO 8229:1991 Operations and baths relating to dry-cleaning machines – Vocabulary ISO 8277:2013 Ships and marine technology – Pipework and machinery – Information transfer ISO 8297:1994 Acoustics – Determination of sound power levels of multisource industrial plants for evaluation of sound pressure levels in the environment – Engineering method ISO 8316:1987 Measurement of liquid flow in closed conduits – Method by collection of the liquid in a volumetric tank ISO 8317:2015 Child-resistant packaging - Requirements and testing procedures for reclosable packages ISO 8319 Orthopaedic instruments – Drive connections ISO 8319-1:1996 Part 1: Keys for use with screws with hexagon socket heads ISO 8319-2:1986 Part 2: Screwdrivers for single slot head screws, screws with cruciate slot and cross-recessed head screws ISO/IEC 8326:1996 Information technology – Open Systems Interconnection – Session service definition ISO/IEC 8327 Information technology – Open Systems Interconnection – Connection-oriented Session protocol ISO/IEC 8327-1:1996 Protocol specification ISO/IEC 8327-2:1996 Protocol Implementation Conformance Statement (PICS) proforma ISO 8330:2014 Rubber and plastics hoses and hose assemblies - Vocabulary ISO 8333:1985 Liquid flow measurement in open channels by weirs and flumes – V-shaped broad-crested weirs ISO 8343:1985 Ferronickel - Determination of silicon content - Gravimetric method ISO/IEC 8348:2002 Information technology – Open Systems Interconnection – Network service definition ISO 8362 Injection containers and accessories ISO 8362-1:2009 Part 1: Injection vials made of glass tubing ISO 8362-2:2015 Part 2: Closures for injection vials ISO 8362-3:2001 Part 3: Aluminium caps for injection vials ISO 8362-4:2011 Part 4: Injection vials made of moulded glass ISO 8362-5:2016 Part 5: Freeze drying closures for injection vials ISO 8362-6:2010 Part 6: Caps made of aluminium-plastics combinations for injection vials ISO 8362-7:2006 Part 7: Injection caps made of aluminium-plastics combinations without overlapping plastics part ISO/TR 8363:1997 Measurement of liquid flow in open channels — General guidelines for selection of method [Withdrawn: replaced by ISO 18365] ISO 8368:1999 Hydrometric determinations – Flow measurements in open channels using structures – Guidelines for selection of structure ISO 8373:2012 Manipulating industrial robots – Vocabulary ISO 8378 Information processing – Data interchange on 130 mm (5.25 in) flexible disk cartridges using modified frequency modulation recording at 7 958 ftprad, 3,8 tpmm (96 tpi), on both sides ISO 8378-1:1986 Part 1: Dimensional, physical and magnetic characteristics ISO 8378-2:1986 Part 2: Track format A ISO 8378-3:1986 Part 3: Track format B ISO 8384:2000 Ships and marine technology – Dredgers – Vocabulary ISO 8388:1998 Knitted fabrics – Types – Vocabulary ISO 8421 Fire protection - Vocabulary ISO 8421-1:1987 Part 1: General terms and phenomena of fire ISO 8421-2:1987 Part 2: Structural fire protection ISO 8421-6:1987 Part 6: Evacuation and means of escape ISO 8421-7:1987 Part 7: Explosion detection and suppression means ISO 8422:2006 Sequential sampling plans for inspection by attributes ISO 8423:2008 Sequential sampling plans for inspection by variables for percent nonconforming (known standard deviation) ISO 8429:1986 Optics and optical instruments – Ophthalmology – Graduated dial scale ISO 8439:1990 Forms design - Basic layout ISO 8440:1986 Location of codes in trade documents ISO/IEC 8441 Information technology – High density digital recording (HDDR) ISO/IEC 8441-1:1991 Part 1: Unrecorded magnetic tape for (HDDR) applications ISO/IEC 8441-2:1991 Part 2: Guide for interchange practice ISO 8459:2009 Information and documentation - Bibliographic data element directory for use in data exchange and enquiry ISO 8462 Information processing – Data interchange on 6,30 mm (0.25 in) magnetic tape cartridge using GCR recording at 394 ftpmm (10 000 ftpi), 39 cpmm (1 000 cpi) ISO 8462-1:1986 Part 1: Mechanical, physical and magnetic properties ISO 8462-2:1986 Part 2: Streaming mode ISO/IEC 8473 Information technology – Protocol for providing the connectionless-mode network service ISO/IEC 8473-1:1998 Protocol specification ISO/IEC 8473-2:1996 Part 2: Provision of the underlying service by an ISO/IEC 8802 subnetwork ISO/IEC 8473-3:1995 Provision of the underlying service by an X.25 subnetwork ISO/IEC 8473-4:1995 Provision of the underlying service by a subnetwork that provides the OSI data link service ISO/IEC 8473-5:1997 Provision of the underlying service by ISDN circuit-switched B-channels ISO/IEC 8480:1995 Information technology – Telecommunications and information exchange between systems – DTE/DCE interface back-up control operation using ITU-T Recommendation V.24 interchange circuits ISO/IEC 8481:1996 Information technology – Telecommunications and information exchange between systems – DTE to DTE direct connections ISO/IEC 8482:1993 Information technology – Telecommunications and information exchange between systems – Twisted pair multipoint interconnections ISO/IEC 8484:2014 Information technology – Magnetic stripes on savingsbooks ISO 8485:1989 Programming languages - APL ISO 8498:1990 Woven fabrics – Description of defects – Vocabulary ISO 8499:2003 Knitted fabrics – Description of defects – Vocabulary ISO 8501 Preparation of steel substrates before application of paints and related products – Visual assessment of surface cleanliness ISO 8501-1:2007 Part 1: Rust grades and preparation grades of uncoated steel substrates and of steel substrates after overall removal of previous coatings ISO 8501-2:1994 Part 2: Preparation grades of previously coated steel substrates after localized removal of previous coatings ISO 8501-3:2006 Part 3: Preparation grades of welds, edges and other areas with surface imperfections ISO 8501-4:2006 Part 4: Initial surface conditions, preparation grades and flash rust grades in connection with high-pressure water jetting ISO 8502 Preparation of steel substrates before application of paints and related products - Tests for the assessment of surface cleanliness ISO 8502-2:2017 Part 2: Laboratory determination of chloride on cleaned surfaces ISO 8502-3:2017 Part 3: Assessment of dust on steel surfaces prepared for painting (pressure-sensitive tape method) ISO 8502-4:2017 Part 4: Guidance on the estimation of the probability of condensation prior to paint application ISO 8502-5:1998 Part 5: Measurement of chloride on steel surfaces prepared for painting (ion detection tube method ISO 8502-6:2006 Part 6: Extraction of soluble contaminants for analysis - The Bresle method ISO 8502-9:1998 Part 9: Field method for the conductometric determination of water-soluble salts ISO 8502-11:2006 Part 11: Field method for the turbidimetric determination of water-soluble sulfate ISO 8503 Preparation of steel substrates before application of paints and related products - Surface roughness characteristics of blast-cleaned steel substrates ISO 8503-1:2012 Part 1: Specifications and definitions for ISO surface profile comparators for the assessment of abrasive blast-cleaned surfaces ISO 8503-2:2012 Part 2: Method for the grading of surface profile of abrasive blast-cleaned steel - Comparator procedure ISO 8503-3:2012 Part 3: Method for the calibration of ISO surface profile comparators and for the determination of surface profile - Focusing microscope procedure ISO 8503-4:2012 Part 4: Method for the calibration of ISO surface profile comparators and for the determination of surface profile - Stylus instrument procedure ISO 8503-5:2017 Part 5: Replica tape method for the determination of the surface profile ISO 8504 Preparation of steel substrates before application of paints and related products - Surface preparation methods ISO 8504-1:2000 Part 1: General principles ISO 8504-2:2000 Part 2: Abrasive blast-cleaning ISO 8504-3:1993 Part 3: Hand- and power-tool cleaning ISO 8506:2024 Information technology — Automatic identification and data capture technology — AIDC application in industrial construction ISO 8512 Surface plates ISO 8512-1:1990 Part 1: Cast iron ISO 8512-2:1990 Part 2: Granite ISO/TR 8517:1988 Rubber- or plastics-covered rollers – Glossary ISO 8525:2008 Airborne noise emitted by machine tools – Operating conditions for metal-cutting machines ISO 8528 Reciprocating internal combustion engine driven alternating current generating sets ISO 8528-1:2005 Part 1: Application, ratings and performance ISO 8528-2:2005 Part 2: Engines ISO 8528-3:2005 Part 3: Alternating current generators for generating sets ISO 8528-4:2005 Part 4: Controlgear and switchgear ISO 8528-5:2013 Part 5: Generating sets ISO 8528-6:2005 Part 6: Test methods ISO 8528-7:2017 Part 7: Technical declarations for specification and design ISO 8528-8:2016 Part 8: Requirements and tests for low-power generating sets ISO 8528-9:2017 Part 9: Measurement and evaluation of mechanical vibrations ISO 8528-10:1998 Part 10: Measurement of airborne noise by the enveloping surface method ISO 8528-12:1997 Part 12: Emergency power supply to safety services ISO 8528-13:2016 Part 13: Safety ISO 8529 Reference neutron radiations ISO 8529-1:2001 Part 1: Characteristics and methods of production ISO 8529-2:2000 Part 2: Calibration fundamentals of radiation protection devices related to the basic quantities characterizing the radiation field ISO 8529-3:1998 Part 3: Calibration of area and personal dosimeters and determination of response as a function of energy and angle of incidence ISO 8532:1995 Securities – Format for transmission of certificate numbers ISO 8536 Infusion equipment for medical use ISO 8536-1:2011 Part 1: Infusion glass bottles ISO 8536-2:2010 Part 2: Closures for infusion bottles ISO 8536-3:2009 Part 3: Aluminium caps for infusion bottles ISO 8536-4:2010 Part 4: Infusion sets for single use, gravity feed ISO 8536-5:2004 Part 5: Burette infusion sets for single use, gravity feed ISO 8536-6:2016 Part 6: Freeze drying closures for infusion bottles ISO 8536-7:2009 Part 7: Caps made of aluminium-plastics combinations for infusion bottles ISO 8536-8:2015 Part 8: Infusion sets for single use with pressure infusion apparatus ISO 8536-9:2015 Part 9: Fluid lines for single use with pressure infusion equipment ISO 8536-10:2015 Part 10: Accessories for fluid lines for single use with pressure infusion equipment ISO 8536-11:2015 Part 11: Infusion filters for single use with pressure infusion equipment ISO 8536-12:2007 Part 12: Check valves ISO 8536-13:2016 Part 13: Graduated flow regulators for single use with fluid contact ISO 8536-14:2016 Part 14: Clamps and flow regulators for transfusion and infusion equipment without fluid contact ISO 8537:2016 Sterile single-use syringes, with or without needle, for insulin ISO 8540:1993 Open front mechanical power presses - Vocabulary ISO 8548 Prosthetics and orthotics – Limb deficiencies ISO 8548-1:1989 Part 1: Method of describing limb deficiencies present at birth ISO 8548-2:1993 Part 2: Method of describing lower limb amputation stumps ISO 8548-3:1993 Part 3: Method of describing upper limb amputation stumps ISO 8548-4:1998 Part 4: Description of causal conditions leading to amputation ISO 8548-5:2003 Part 5: Description of the clinical condition of the person who has had an amputation ISO 8549 Prosthetics and orthotics - Vocabulary ISO 8549-1:1989 Part 1: General terms for external limb prostheses and external orthoses ISO 8549-2:1989 Part 2: Terms relating to external limb prostheses and wearers of these prostheses ISO 8549-3:1989 Part 3: Terms relating to external orthoses ISO 8549-4:2014 Part 4: Terms relating to limb amputation ISO/TR 8550 Guidance on the selection and usage of acceptance sampling systems for inspection of discrete items in lots ISO/TR 8550-1:2007 Part 1: Acceptance sampling ISO/TR 8550-2:2007 Part 2: Sampling by attributes ISO/TR 8550-3:2007 Part 3: Sampling by variables ISO 8551:2003 Prosthetics and orthotics – Functional deficiencies – Description of the person to be treated with an orthosis, clinical objectives of treatment, and functional requirements of the orthosis ISO 8552:2004 Milk – Estimation of psychrotrophic microorganisms – Colony-count technique at 21 degrees C (Rapid method) ISO 8553:2004 Milk – Enumeration of microorganisms – Plate-loop technique at 30 degrees C ISO 8559:1989 Garment construction and anthropometric surveys – Body dimensions [Withdrawn: replaced by ISO 8559-1:2017] ISO 8559 Size designation of clothes ISO 8559-1:2017 Part 1: Anthropometric definitions for body measurement ISO 8559-2:2017 Part 2: Primary and secondary dimension indicators ISO 8560:1986 Technical drawings – Construction drawings – Representation of modular sizes, lines and grids ISO 8568:2007 Mechanical shock – Testing machines – Characteristics and performance ISO 8571 Information processing systems - Open Systems Interconnection - File Transfer, Access and Management ISO 8571-1:1988 Part 1: General introduction ISO 8571-2:1988 Part 2: Virtual Filestore Definition ISO 8571-3:1988 Part 3: File Service Definition ISO 8571-4:1988 Part 4: File Protocol Specification ISO/IEC 8571-5:1990 Part 5: Protocol Implementation Conformance Statement Proforma ISO 8573 Compressed air ISO 8573-1:2010 Contaminants and purity classes ISO 8573-2:2007 Test methods for oil aerosol content ISO 8573-3:1999 Test methods for measurement of humidity ISO 8573-4:2001 Test methods for solid particle content ISO 8573-5:2001 Test methods for oil vapour and organic solvent content ISO 8573-6:2003 Test methods for gaseous contaminant content ISO 8573-7:2003 Test method for viable microbiological contaminant content ISO 8573-8:2004 Test methods for solid particle content by mass concentration ISO 8573-9:2004 Test methods for liquid water content ISO 8579 Acceptance code for gear units ISO 8579-1:2002 Part 1: Test code for airborne sound ISO 8583 Financial transaction card originated messages – Interchange message specifications ISO 8586:2012 Sensory analysis – General guidelines for the selection, training and monitoring of selected assessors and expert sensory assessors ISO 8596:2009 Ophthalmic optics – Visual acuity testing – Standard optotype and its presentation ISO 8598 Optics and optical instruments – Focimeters ISO 8598-1:2014 Part 1: General purpose instruments ISO 8600 Endoscopes – Medical endoscopes and endotherapy devices ISO 8600-1:2015 Part 1: General requirements ISO 8600-2:2015 Part 2: Particular requirements for rigid bronchoscopes ISO 8600-3:1997 Part 3: Determination of field of view and direction of view of endoscopes with optics ISO 8600-4:2014 Part 4: Determination of maximum width of insertion portion ISO 8600-5:2005 Part 5: Determination of optical resolution of rigid endoscopes with optics ISO 8600-6:2005 Part 6: Vocabulary ISO 8600-7:2012 Part 7: Basic requirements for medical endoscopes of water-resistant type ISO 8601:2019 Data elements and interchange formats – Information interchange – Representation of dates and times ISO/IEC 8602:1995 Information technology – Protocol for providing the OSI connectionless-mode transport service ISO 8604:1988 Plastics – Prepregs – Definitions of terms and symbols for designations ISO 8608:2016 Mechanical vibration – Road surface profiles – Reporting of measured data ISO 8612:2009 Ophthalmic instruments – Tonometers ISO/IEC 8613 Information technology – Open Document Architecture (ODA) and interchange format ISO 8614:1997 Ski bindings – Vocabulary ISO 8615:1991 Implants for surgery – Fixation devices for use in the ends of the femur in adults ISO 8624:2011 Ophthalmic optics – Spectacle frames – Measuring system and terminology ISO 8625 Aerospace – Fluid systems – Vocabulary ISO 8625-1:1993 Part 1: General terms and definitions related to pressure ISO 8625-2:1991 Part 2: General terms and definitions relating to flow ISO 8625-3:1991 Part 3: General terms and definitions relating to temperature ISO 8625-4:2011 Part 4: General terms and definitions relating to control/actuation systems ISO 8626:1989 Servo-hydraulic test equipment for generating vibration – Method of describing characteristics ISO 8630 Information processing – Data interchange on 130 mm (5.25 in) flexible disk cartridges using modified frequency modulation recording at 13 262 ftprad, on 80 tracks on each side ISO 8630-1:1987 Part 1: Dimensional, physical and magnetic characteristics ISO 8630-2:1987 Part 2: Track format A for 77 tracks ISO 8630-3:1987 Part 3: Track format B for 80 tracks ISO/IEC 8631:1989 Information technology - Program constructs and conventions for their representation ISO/IEC 8632 Information technology – Computer graphics – Metafile for the storage and transfer of picture description information ISO/IEC 8632-1:1999 Part 1: Functional specification ISO/IEC 8632-2:1992 Part 2: Character encoding [withdrawn 2001-06-21] ISO/IEC 8632-3:1999 Part 3: Binary encoding ISO/IEC 8632-4:1999 Part 4: Clear text encoding ISO 8637:2010 Cardiovascular implants and extracorporeal systems – Haemodialysers, haemodiafilters, haemofilters and haemoconcentrators ISO 8638:2010 Cardiovascular implants and extracorporeal systems – Extracorporeal blood circuit for haemodialysers, haemodiafilters and haemofilters ISO 8640 Textile machinery and accessories – Flat warp knitting machines ISO 8640-1:2004 Part 1: Vocabulary of basic structure and knitting elements ISO 8640-2:2004 Part 2: Vocabulary of warp let-off, fabric take-up and batching ISO 8640-3:2002 Part 3: Vocabulary of patterning devices ISO 8640-4:1996 Part 4: Stitch bonding machines and stitch bonding devices ISO 8648:1988 Information processing systems – Open Systems Interconnection – Internal organization of the Network Layer ISO/IEC 8650 Information technology – Open Systems Interconnection – Protocol specification for the Association Control Service Element ISO/IEC 8650-2:1997 Protocol Implementation Conformance Statement (PICS) proforma ISO 8651 Information technology – Computer graphics – Graphical Kernel System (GKS) language bindings ISO 8651-1:1988 Part 1: FORTRAN ISO 8651-2:1988 Part 2: Pascal ISO 8651-3:1988 Part 3: Ada ISO/IEC 8651-4:1995 Part 4: C ISO/IEC 8652:2012 Information technology – Programming languages – Ada ISO 8653:1986 Jewellery – Ring-sizes – Definition, measurement and designation ISO 8655 Piston-operated volumetric apparatus ISO 8655-1:2002 Part 1: Terminology, general requirements and user recommendations ISO 8655-2:2002 Part 2: Piston pipettes ISO 8655-3:2002 Part 3: Piston burettes ISO 8655-4:2002 Part 4: Dilutors ISO 8655-5:2002 Part 5: Dispensers ISO 8655-6:2002 Part 6: Gravimetric methods for the determination of measurement error ISO 8655-7:2005 Part 7: Non-gravimetric methods for the assessment of equipment performance ISO 8669 Urine collection bags ISO 8669-1:1988 Part 1: Vocabulary ISO 8670 Ostomy collection bags ISO 8670-1:1988 Part 1: Vocabulary ISO 8691 Petroleum products – Low levels of vanadium in liquid fuels – Determination by flameless atomic absorption spectrometry after ashing ISO 8695:2010 Tools for pressing - Punches - Nomenclature and terminology ISO/TR 8713:2012 Electrically propelled road vehicles – Vocabulary ISO 8769:2016 Reference sources - Calibration of surface contamination monitors - Alpha-, beta- and photon emitters ISO 8777:1993 Information and documentation - Commands for interactive text searching ISO 8784 Pulp, paper and board – Microbiological examination ISO 8784-1:2014 Part 1: Enumeration of bacteria and bacterial spores based on disintegration ISO 8785:1998 Geometrical Product Specification (GPS) - Surface imperfections - Terms, definitions and parameters ISO 8790:1987 Information processing systems - Computer system configuration diagram symbols and conventions ISO/IEC 8802 Information technology – Telecommunications and information exchange between systems – Local and metropolitan area networks – Specific requirements ISO/IEC/IEEE 8802-A:2015 Part A: Overview and architecture ISO/IEC TR 8802-1:2001 Part 1: Overview of Local Area Network Standards ISO/IEC/IEEE 8802-1Q:2016 Part 1Q: Bridges and bridged networks ISO/IEC/IEEE 8802-1X:2013 Part 1X: Port-based network access control ISO/IEC/IEEE 8802-1AB:2017 Part 1AB: Station and media access control connectivity discovery ISO/IEC/IEEE 8802-1AE:2013 Part 1AE: Media access control (MAC) security ISO/IEC/IEEE 8802-1AR:2014 Part 1AR: Secure device identity ISO/IEC/IEEE 8802-1AS:2014 Part 1AS: Timing and synchronization for time-sensitive applications in bridged local area networks ISO/IEC/IEEE 8802-1AX:2016 Part 1AX: Link aggregation ISO/IEC/IEEE 8802-1BA:2016 Part 1BA: Audio video bridging (AVB) systems ISO/IEC/IEEE 8802-1BR:2016 Part 1BR: Virtual bridged local area networks – Bridge port extension ISO/IEC 8802-2:1998 Part 2: Logical link control ISO/IEC/IEEE 8802-3:2017 Part 3: Standard for Ethernet ISO/IEC/IEEE 8802-3-1:2015 Part 3-1: Standard for management information base (MIB) – Definitions for Ethernet ISO/IEC 8802-5:1998 Part 5: Token Ring access method and physical layer specifications ISO/IEC/IEEE 8802-11:2012 Part 11: Wireless LAN medium access control (MAC) and physical layer (PHY) specifications ISO/IEC/IEEE 8802-15-4:2010 Part 15-4: Wireless medium access control (MAC) and physical layer (PHY) specifications for low-rate wireless personal area networks (WPANs) ISO/IEC/IEEE 8802-22:2015 Part 22: Cognitive Wireless RAN Medium Access Control (MAC) and Physical Layer (PHY) Specifications: Policies and Procedures for Operation in the TV Bands ISO 8805 Information processing systems – Computer graphics – Graphical Kernel System for Three Dimensions (GKS-3D) functional description ISO/IEC 8806 Information technology – Computer graphics – Graphical Kernel System for Three Dimensions (GKS-3D) language bindings ISO/IEC 8806-4 Part 4: C ISO 8807:1989 Information processing systems – Open Systems Interconnection – LOTOS – A formal description technique based on the temporal ordering of observational behaviour ISO 8811:2000 Earth-moving machinery – Rollers and compactors – Terminology and commercial specifications ISO 8812:2016 Earth-moving machinery – Backhoe loaders – Terminology and commercial specifications ISO 8815:1994 Aircraft – Electrical cables and cable harnesses – Vocabulary ISO/IEC 8822:1994 Information technology – Open Systems Interconnection – Presentation service definition ISO/IEC 8823 Information technology – Open Systems Interconnection – Connection-oriented presentation protocol ISO/IEC 8823-1:1994 Protocol specification ISO/IEC 8823-2:1997 Protocol Implementation Conformance Statement (PICS) proforma ISO/IEC 8824 Information technology – Abstract Syntax Notation One (ASN.1) ISO/IEC 8824-1:2015 Specification of basic notation ISO/IEC 8824-2:2015 Information object specification ISO/IEC 8824-3:2015 Constraint specification ISO/IEC 8824-4:2015 Parameterization of ASN.1 specifications ISO/IEC 8825 Information technology – ASN.1 encoding rules ISO/IEC 8825-1:2015 Specification of Basic Encoding Rules (BER), Canonical Encoding Rules (CER) and Distinguished Encoding Rules (DER) ISO/IEC 8825-2:2015 Specification of Packed Encoding Rules (PER) ISO/IEC 8825-3:2015 Specification of Encoding Control Notation (ECN) ISO/IEC 8825-4:2015 XML Encoding Rules (XER) ISO/IEC 8825-5:2015 Mapping W3C XML schema definitions into ASN.1 ISO/IEC 8825-6:2015 Registration and application of PER encoding instructions ISO/IEC 8825-7:2015 Part 7: Specification of Octet Encoding Rules (OER) ISO 8826 Technical drawings – Rolling bearings ISO 8826-1:1989 Part 1: General simplified representation ISO 8826-2:1994 Part 2: Detailed simplified representation ISO 8827:1988 Implants for surgery – Staples with parallel legs for orthopaedic use – General requirements ISO 8828:2014 Implants for surgery – Guidance on care and handling of orthopaedic implants ISO 8835 Inhalational anaesthesia systems ISO 8835-7:2011 Part 7: Anaesthetic systems for use in areas with limited logistical supplies of electricity and anaesthetic gases ISO 8836:2014 Suction catheters for use in the respiratory tract ISO 8843:2005 Aircraft – Crimp-removable contacts for electrical connectors – Identification system ISO 8855:2011 Road vehicles – Vehicle dynamics and road-holding ability – Vocabulary ISO/IEC 8859 Information technology – 8-bit single-byte coded graphic character sets ISO/IEC 8859-1:1998 Part 1: Latin alphabet No. 1 ISO/IEC 8859-2:1999 Part 2: Latin alphabet No. 2 ISO/IEC 8859-3:1999 Part 3: Latin alphabet No. 3 ISO/IEC 8859-4:1998 Part 4: Latin alphabet No. 4 ISO/IEC 8859-5:1999 Part 5: Latin/Cyrillic alphabet ISO/IEC 8859-6:1999 Part 6: Latin/Arabic alphabet ISO/IEC 8859-7:2003 Part 7: Latin/Greek alphabet ISO/IEC 8859-8:1999 Part 8: Latin/Hebrew alphabet ISO/IEC 8859-9:1999 Part 9: Latin alphabet No. 5 ISO/IEC 8859-10:1998 Part 10: Latin alphabet No. 6 ISO/IEC 8859-11:2001 Part 11: Latin/Thai alphabet ISO/IEC 8859-13:1998 Part 13: Latin alphabet No. 7 ISO/IEC 8859-14:1998 Part 14: Latin alphabet No. 8 (Celtic) ISO/IEC 8859-15:1999 Part 15: Latin alphabet No. 9 ISO/IEC 8859-16:2001 Part 16: Latin alphabet No. 10 ISO 8860 Information processing – Data interchange on 90 mm (3.5 in) flexible disk cartridges using modified frequency modulation recording at 7 958 ftprad on 80 tracks on each side ISO 8860-1:1987 Part 1: Dimensional, physical and magnetic characteristics ISO 8860-2:1987 Part 2: Track format ISO 8871 Elastomeric parts for parenterals and for devices for pharmaceutical use ISO 8871-1:2003 Part 1: Extractables in aqueous autoclavates ISO 8871-2:2003 Part 2: Identification and characterization ISO 8871-3:2003 Part 3: Determination of released-particle count ISO 8871-4:2006 Part 4: Biological requirements and test methods ISO 8871-5:2016 Part 5: Functional requirements and testing ISO 8872:2003 Aluminium caps for transfusion, infusion and injection bottles – General requirements and test methods ISO/IEC 8877:1992 Information technology – Telecommunications and information exchange between systems – Interface connector and contact assignments for ISDN Basic Access Interface located at reference points S and T ISO/IEC 8878:1992 Information technology – Telecommunications and information exchange between systems – Use of X.25 to provide the OSI Connection-mode Network Service ISO 8879:1986 Information processing – Text and office systems – Standard Generalized Markup Language (SGML) ISO/IEC 8880 Information technology — Telecommunications and information exchange between systems — Protocol combinations to provide and support the OSI Network Service ISO/IEC 8880-1:1990 Part 1: General principles [Withdrawn: replaced by ISO/IEC TR 13532:1995, now withdrawn without replacement] ISO/IEC 8880-2:1992 Part 2: Provision and support of the connection-mode Network Service [Withdrawn: replaced by ISO/IEC TR 13532:1995, now withdrawn without replacement] ISO/IEC 8880-3:1990 Part 3: Provision and support of the connectionless-mode Network Service [Withdrawn: replaced by ISO/IEC TR 13532:1995, now withdrawn without replacement] ISO/IEC 8881:1989 Information processing systems – Data communications – Use of the X.25 packet level protocol in local area networks ISO/IEC 8882 Information technology – Telecommunications and information exchange between systems – X.25 DTE conformance testing ISO/IEC 8882-1:1996 Part 1: General principles ISO/IEC 8882-2:2000 Part 2: Data link layer conformance test suite ISO/IEC 8882-3:2000 Part 3: Packet layer conformance test suite ISO 8884:1989 Information processing — Text and office systems — Keyboards for multiple Latin-alphabet languages — Layout and operation [Withdrawn: replaced with ISO 9995-(1,7)] ISO 8885:1987 Information processing systems — Data communication — High-level data link control procedures — General purpose XID frame information field content and format [Withdrawn without replacement] ISO/IEC 8886:1996 Information technology – Open Systems Interconnection – Data link service definition ISO 8887 Technical product documentation – Design for manufacturing, assembling, disassembling and end-of-life processing ISO 8887-1:2017 Part 1: General concepts and requirements ISO 8891:1998 Dental casting alloys with noble metal content of at least 25 % but less than 75 % [Withdrawn: replaced with ISO 22674] ISO 8909 Forage harvesters ISO 8909-1:1994 Part 1: Vocabulary ISO 8910:1993 Machinery and equipment for working the soil – Mouldboard plough working elements – Vocabulary ISO 8927:1991 Earth-moving machinery – Machine availability – Vocabulary ISO 8930:1987 General principles on reliability for structures – List of equivalent terms ISO 8936:2017 Awnings for leisure accommodation vehicles - Requirements and test methods ISO 8954 Ferroalloys - Vocabulary ISO 8954-1:1990 Part 1: Materials ISO 8954-2:1990 Part 2: Sampling and sample preparation ISO 8954-3:1990 Part 3: Sieve analysis ISO 8957:1996 Information and documentation - Hebrew alphabet coded character sets for bibliographic information interchange ISO 8965:2013 Logging industry – Technology – Terms and definitions ISO 8979:2004 Pliers and nippers for electronics - Nomenclature ISO 8980 Ophthalmic optics – Uncut finished spectacle lenses ISO 8980-1:2017 Part 1: Specifications for single-vision and multifocal lenses ISO 8980-2:2017 Part 2: Specifications for power-variation lenses ISO 8980-3:2013 Part 3: Transmittance specifications and test methods ISO 8980-4:2006 Part 4: Specifications and test methods for anti-reflective coatings ISO 8980-5:2005 Part 5: Minimum requirements for spectacle lens surfaces claimed to be abrasion-resistant ISO 8999:2001 Reciprocating internal combustion engines - Graphical symbols
== Oscillatory behavior == When blood glucose levels are too low, the pancreas is signaled to release glucagon, which has essentially the opposite effect of insulin and therefore opposes the reduction of glucose in the blood. Glucagon is delivered directly to the liver, where it connects to the glucagon receptors on the membranes of the liver cells, signals the conversion of the glycogen already stored in the liver cells into glucose. This process is called glycogenolysis. Conversely, when the blood glucose levels are too high, the pancreas is signaled to release insulin. Insulin is delivered to the liver and other tissues throughout the body (e.g., muscle, adipose). When the insulin is introduced to the liver, it connects to the insulin receptors already present, that is tyrosine kinase receptor. These receptors have two alpha subunits (extracellular) and two beta subunits (intercellular) which are connected through the cell membrane via disulfide bonds. When the insulin binds to these alpha subunits, 'glucose transport 4' (GLUT4) is released and transferred to the cell membrane to regulate glucose transport in and out of the cell. With the release of GLUT4, the allowance of glucose into cells is increased, and therefore the concentration of blood glucose might decrease. This, in other words, increases the utilization of the glucose already present in the liver. This is shown in the adjacent image.
Sources: en.wikipedia.org
==== Canada ==== In Canada, Pfizer's patent 2,324,324 for Revatio (sildenafil used to treat pulmonary hypertension) was found invalid by the Federal Court in June 2010, on an application by Ratiopharm Inc. On 8 November 2012, the Supreme Court of Canada ruled that Pfizer's patent 2,163,446 on Viagra was invalid from the beginning because the company did not provide full disclosure in its application. The decision, Teva Canada Ltd. v. Pfizer Canada Inc., pointed to section 27(3)(b) of The Patent Act which requires that disclosure must include sufficient information "to enable any person skilled in the art or science to which it pertains" to produce it. It added further: "As a matter of policy and sound statutory interpretation, patentees cannot be allowed to 'game' the system in this way. This, in my view, is the key issue in this appeal." Teva Canada launched Novo-Sildenafil, a generic version of Viagra, on the day the Supreme Court of Canada released its decision. To remain competitive, Pfizer then reduced the price of Viagra in Canada. However, on 9 November 2012, Pfizer filed a motion for a re-hearing of the appeal in the Supreme Court of Canada, on the grounds that the court accidentally exceeded its jurisdiction by voiding the patent. Finally, on 22 April 2013, the Supreme Court of Canada invalidated Pfizer's patent altogether.
Several immunodeficiency syndromes present clinical and laboratory characteristics of autoimmunity. The decreased ability of the immune system to clear infections in these patients may be responsible for causing autoimmunity through perpetual immune system activation. One example is common variable immunodeficiency (CVID), where multiple autoimmune diseases are seen, e.g., inflammatory bowel disease, autoimmune thrombocytopenia, and autoimmune thyroid disease. Familial hemophagocytic lymphohistiocytosis, an autosomal recessive primary immunodeficiency, is another example. Low blood levels of red blood cells, white blood cells, and platelets, rashes, lymph node enlargement, and enlargement of the liver and spleen are commonly seen in these patients. The presence of multiple uncleared viral infections due to a lack of perforin is thought to be responsible. In addition to chronic and/or recurrent infections, many autoimmune diseases, including arthritis, autoimmune hemolytic anemia, scleroderma, and type 1 diabetes, are also seen in X-linked agammaglobulinemia (XLA). Recurrent bacterial and fungal infections and chronic inflammation of the gut and lungs are seen in chronic granulomatous disease (CGD). CGD is caused by a decreased production of nicotinamide adenine dinucleotide phosphate (NADPH) oxidase by neutrophils. Hypomorphic RAG mutations are seen in patients with midline granulomatous disease; an autoimmune disorder commonly occurring in patients with granulomatosis with polyangiitis and NK/T cell lymphomas.
=== Biochemistry and biomedical uses === Sodium azide is a useful probe reagent, and an antibacterial preservative for biochemical solutions. In the past merthiolate and chlorobutanol were also used as an alternative to azide for preservation of biochemical solutions. Sodium azide is an instantaneous inhibitor of lactoperoxidase, which can be useful to stop lactroperoxidase catalyzed 125I protein radiolabeling experiments. In hospitals and laboratories, it is a biocide; it is especially important in bulk reagents and stock solutions which may otherwise support bacterial growth where the sodium azide acts as a bacteriostatic by inhibiting cytochrome oxidase in gram-negative bacteria; however, some gram-positive bacteria (streptococci, pneumococci, lactobacilli) are intrinsically resistant.
The GPUGRID.net Project (GPUGRID.net) The Blue Gene Project (IBM) JawBreakers.org Materials modelling and computer simulation codes A few tips on molecular dynamics Movie of MD simulation of water (YouTube)
The territorial organisation of the Republic of Serbia was regulated by the Law on Territorial Organisation and Local Self-Government, adopted in the Assembly of Serbia on 24 July 1991. Under the Law, the municipalities, cities and settlements make the bases of the territorial organization. Serbia was divided into 195 municipalities and 4 cities, which were the basic units of local autonomy. It had two autonomous provinces: Kosovo and Metohija in the south (with 30 municipalities), which was under the administration of UNMIK after 1999, and Vojvodina in the north (with 46 municipalities and 1 city). The territory between Kosovo and Vojvodina was called Central Serbia. Central Serbia was not an administrative division on its own and had no regional government of its own. In addition, there were four cities: Belgrade, Niš, Novi Sad and Kragujevac, each having an assembly and budget of its own. The cities comprised several municipalities, divided into "urban" (in the city proper) and "other" (suburban). Competences of cities and their municipalities were divided. Municipalities were gathered into districts, which are regional centres of state authority, but have no assemblies of their own; they present purely administrative divisions, and host various state institutions such as funds, office branches and courts. The Republic of Serbia was then and is still today divided into 29 districts (17 in Central Serbia, 7 in Vojvodina and 5 in Kosovo, which are now defunct), while the city of Belgrade presents a district of its own.
Sources: en.wikipedia.org
=== Gastrointestinal decontamination === In adults, the initial treatment for paracetamol overdose is gastrointestinal decontamination. Paracetamol absorption from the gastrointestinal tract is complete within two hours under normal circumstances, so decontamination is most helpful if performed within this timeframe. Gastric lavage, better known as stomach pumping, may be considered if the amount ingested is potentially life-threatening and the procedure can be performed within 60 minutes of ingestion. Administration of activated charcoal is the most common gastrointestinal decontamination procedure as it efficiently adsorbs paracetamol, thereby reducing its gastrointestinal absorption. Administering activated charcoal also poses less risk of aspiration than gastric lavage. It appears that the most benefit from activated charcoal is gained if it is given within 30 minutes to two hours of ingestion. Administering activated charcoal later than 2 hours can be considered in patients that may have delayed gastric emptying due to co-ingested drugs or following ingestion of sustained- or delayed-release paracetamol preparations. Activated charcoal should also be administered if co-ingested drugs warrant decontamination. There was reluctance to give activated charcoal in paracetamol overdose, because of the concern that it may also absorb the oral antidote acetylcysteine. Studies have shown that 39% less acetylcysteine is absorbed into the body when they are administered together.
The result of this pharmacokinetic variability among people is that many people do not receive the right dose to achieve optimal treatment effectiveness with minimized toxic side effects. Some people are overdosed while others are underdosed. For example, in a randomized clinical trial, investigators found 85% of metastatic colorectal cancer patients treated with 5-fluorouracil (5-FU) did not receive the optimal therapeutic dose when dosed by the BSA standard—68% were underdosed and 17% were overdosed. There has been controversy over the use of BSA to calculate chemotherapy doses for people who are obese. Because of their higher BSA, clinicians often arbitrarily reduce the dose prescribed by the BSA formula for fear of overdosing. In many cases, this can result in sub-optimal treatment. Several clinical studies have demonstrated that when chemotherapy dosing is individualized to achieve optimal systemic drug exposure, treatment outcomes are improved and toxic side effects are reduced. In the 5-FU clinical study cited above, people whose dose was adjusted to achieve a pre-determined target exposure realized an 84% improvement in treatment response rate and a six-month improvement in overall survival (OS) compared with those dosed by BSA.
Vasoactive intestinal peptide, also known as vasoactive intestinal polypeptide or VIP, is a peptide hormone that is vasoactive in the intestine. VIP is a peptide of 28 amino acid residues that belongs to a glucagon/secretin superfamily, the ligand of class II G protein–coupled receptors. VIP is produced in many tissues of vertebrates including the gut, pancreas, neocortex, and suprachiasmatic nuclei of the hypothalamus in the brain. VIP stimulates contractility in the heart, causes vasodilation, increases glycogenolysis, lowers arterial blood pressure and relaxes the smooth muscle of trachea, stomach and gallbladder. In humans, the vasoactive intestinal peptide is encoded by the VIP gene. VIP has a half-life (t½) in the blood of about two minutes.
UIUC Histology Subject 777 Illustration at wku.edu Anatomy photo: Musculoskeletal/muscle/skeletal1/skeletal3 - Comparative Organology at University of California, Davis MedEd at Loyola histo/practical/muscle/hp7-42.html
=== Tissue engineering === The ability of SHG to image specific molecules can reveal the structure of a certain tissue one material at a time, and at various scales (from macro to micro) using microscopy. For instance, the collagen (type I) is specifically imaged from the extracellular matrix (ECM) of cells, or when it serves as a scaffold or conjonctive material in tissues. SHG also reveals fibroin in silk, myosin in muscles and biosynthetized cellulose. All of this imaging capability can be used to design artificials tissues, by targeting specific points of the tissue : SHG can indeed quantitatively measure some orientations, and material quantity and arrangement. Also, SHG coupled to other multiphoton techniques can serve to monitor the development of engineered tissues, when the sample is relatively thin however. Of course, they can finally be used as a quality control of the fabricated tissues.
Sources: en.wikipedia.org
Conventional drying uses heat to evaporate water from a material, while lyophilization freezes the material and removes water by sublimation under vacuum. This avoids the liquid phase and reduces thermal damage to sensitive substances. The result is a porous cake that reconstitutes quickly.
A vacuum lowers the pressure below the triple point of water, allowing ice to sublimate directly into vapor without melting. It also removes water vapor from the product chamber and speeds up the drying process. Without vacuum, the ice would melt rather than sublimate.
Not all substances are suitable for lyophilization. Materials must form a stable frozen matrix and tolerate freezing and low pressure. Some small molecules, oils, or volatile compounds may not form a proper cake or may be lost during processing.
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.