Redox ratio 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.
Last reviewed on 2026-06-11. Where a claim depends on a specific study, the study is described rather than over-claimed.
Several techniques are used for quantification. Enzymatic recycling assays rely on glutathione reductase and a colorimetric or fluorescent readout, offering sensitivity for total glutathione. High-performance liquid chromatography can separate GSH from GSSG and other thiols, often with UV, fluorescence, or electrochemical detection. Mass spectrometry provides structural confirmation and can quantify low-abundance species when paired with separation. Each approach has trade-offs in specificity, throughput, and equipment requirements, so method selection depends on the research question and available instrumentation.
Stability depends on pH, temperature, oxygen exposure, and trace metals. Aqueous solutions of reduced glutathione are susceptible to oxidation, especially when neutral or alkaline and exposed to air. Transition metal ions can catalyze thiol oxidation, so chelators and inert atmospheres are sometimes used in research settings. Standards are typically stored cold and desiccated, with limited freeze-thaw cycles. Questions remain about how closely in vitro stability data reflect the behavior of glutathione within intact cells and tissues.
Measuring glutathione requires attention to oxidation during sample handling, because GSH in biological samples can convert to GSSG or form mixed disulfides with proteins after collection. Acidic extraction, rapid cooling, and chelating agents are commonly used to limit such changes. Analytical methods usually distinguish free reduced glutathione, total glutathione, and protein-bound forms. Because these forms have different stability and reactivity, reported values depend heavily on the preparation protocol. No single preparation is universally suitable for every biological matrix or analytical goal.
Measuring glutathione in biological samples requires attention to oxidation and matrix effects. High-performance liquid chromatography with ultraviolet or fluorescence detection can separate reduced and oxidized forms after derivatization. Liquid chromatography with tandem mass spectrometry offers higher specificity and can quantify glutathione alongside related thiols. Because glutathione can oxidize during sample handling, many protocols use rapid acidification with metaphosphoric acid or sulfosalicylic acid. Internal standards help correct for losses during extraction and analysis.
Enzymatic recycling assays provide a complementary approach for total glutathione. In these methods, glutathione reductase reduces oxidized glutathione while a thiol-reactive reagent, such as 5,5'-dithiobis(2-nitrobenzoic acid), produces a colored product. The reaction cycles between reduced and oxidized forms, amplifying the signal. Spectrophotometric or fluorometric detection can then estimate concentration. Distinguishing reduced glutathione from glutathione disulfide often requires separate aliquots, masking agents, or chromatographic separation, and the choice affects reported values.
| Property | Value | Notes |
|---|---|---|
| Reduced form | GSH | Main intracellular thiol |
| Oxidized form | GSSG | Disulfide dimer of two GSH molecules |
| Common separation method | Reversed-phase HPLC | Often with ion-pairing or derivatization |
| Typical detection | Fluorescence or mass spectrometry | UV detection is also used in some assays |
| Storage of standards | -20 °C or below, desiccated | Limit freeze-thaw and moisture exposure |
Common analytical approaches include enzymatic recycling assays, high-performance liquid chromatography, and mass spectrometry. Enzymatic recycling measures total glutathione after converting GSSG back to GSH, while separation methods can quantify GSH and GSSG separately. Derivatization may be used to improve detection or stability during analysis. LC-MS/MS offers high specificity and can distinguish glutathione from related thiols and adducts. Each method has different sensitivity, throughput, and susceptibility to interference, so method selection depends on the study question and sample matrix.
For solid glutathione reagents, storage at low temperature and protection from moisture and light are typical precautions. Aqueous solutions can oxidize over time, and pH affects stability; alkaline conditions generally promote thiol oxidation. Some protocols prepare fresh solutions, while others use antioxidants or chelators to limit metal-catalyzed oxidation. Purity and counterion content can vary among commercial preparations, affecting concentration calculations. Certificates of analysis and validated assays help verify identity and purity.
Measuring glutathione in biological samples requires attention to oxidation, because GSH can convert to GSSG after sample collection. Blood and plasma samples are often treated with acid or alkylating agents to preserve the reduced form. Without stabilization, apparent GSH concentrations can fall while GSSG rises. Differences in sample type, handling delay, and deproteinization method can produce results that are not comparable across studies. Reporting preanalytical details is therefore important for interpreting findings.
Glutathione serves as a cofactor for several enzymes, including glutathione peroxidase and glutathione S-transferase. These enzymes help reduce hydrogen peroxide and lipid peroxides, and they conjugate reactive electrophiles for excretion. The molecule also acts as a reservoir for cysteine, an amino acid that is prone to oxidation. In addition, glutathione participates in the metabolism of nitric oxide, leukotrienes, and prostaglandins. Its roles extend to cell signaling, apoptosis, and the regulation of protein function through S-glutathionylation.
Glutathione is a tripeptide composed of glutamate, cysteine, and glycine, and it is the most abundant non-protein thiol in most living cells. The reduced form, GSH, carries a sulfhydryl group that can donate electrons, while the oxidized form, GSSG, forms when two GSH molecules link via a disulfide bond. The balance between these two forms helps define the cellular redox environment, and their ratio is often used as an indicator of oxidative stress. Because the sulfhydryl group is reactive, glutathione participates in many cellular processes, including detoxification and protein regulation.
Glutathione is synthesized in two ATP-dependent steps. First, gamma-glutamylcysteine synthetase links glutamate and cysteine; second, glutathione synthetase adds glycine to form the complete tripeptide. The pathway is feedback-inhibited by GSH itself, which helps maintain steady intracellular levels. Tissues vary widely in glutathione content, with the liver typically containing the highest concentrations, followed by the kidneys, lungs, and erythrocytes. Because cysteine is often limiting, its availability influences synthesis rates, and regulation of this pathway varies by cell type.
Quality control for glutathione focuses on identity, purity, and oxidation state. Certificates of analysis may report assay value, water content, and the presence of GSSG or other impurities. Chromatographic purity is often expressed as a percentage of peak area. Reference standards help laboratories compare results across instruments and batches. Because glutathione is a small, polar molecule, separation from cysteine, gamma-glutamylcysteine, and related thiols can be challenging. Verification often combines more than one analytical technique.
Measuring glutathione requires attention to sample preparation because the molecule oxidizes readily. Blood, tissue, and cell samples are often treated with acid to precipitate proteins and stabilize the thiol. Without such steps, GSH can convert to GSSG or form mixed disulfides during storage. Analytical methods include spectrophotometric assays, high-performance liquid chromatography, and mass spectrometry. Each approach has different sensitivity, specificity, and susceptibility to interference from related compounds in complex matrices.
Samples for glutathione analysis require careful handling because the compound oxidizes readily and can be consumed by enzymes after collection. Blood is often treated with acid or thiol-blocking agents soon after draw, and plasma should be separated quickly from red blood cells. Tissues are usually snap-frozen or extracted immediately. Aqueous solutions of glutathione are less stable than dry powder and degrade faster at neutral or alkaline pH, in light, or with dissolved oxygen. Repeated freeze-thaw cycles also reduce reliability.
Quality control for glutathione materials checks identity, assay, purity, water content, and disulfide content. Commercial products vary from research-grade powder to dietary supplements, and labels may not distinguish reduced from oxidized forms. In the United States, oral glutathione is commonly sold as a dietary supplement rather than an approved drug, while injectable forms fall under different rules and may require a prescription. Regulatory status differs by country. Analytical certificates, when available, help verify what a material contains, but independent testing remains important for interpretation.
Laboratory measurement of glutathione typically starts with rapid acid extraction to prevent oxidation and enzymatic degradation. Common methods include enzymatic recycling assays, high-performance liquid chromatography, and liquid chromatography coupled with mass spectrometry. The recycling assay uses glutathione reductase and a thiol-reactive colorimetric or fluorescent reagent, measuring total glutathione after converting disulfide forms. Chromatographic methods can separate reduced and oxidized forms, which helps when the redox ratio is the target. Choice of method affects sensitivity, specificity, and the amount of sample needed.
Although previous studies proposed that Komodo dragon saliva contains a variety of highly septic bacteria that would help to bring down prey, research in 2013 suggested that the bacteria in the mouths of Komodo dragons are ordinary and similar to those found in other carnivores. Komodo dragons have good mouth hygiene. To quote Bryan Fry: "After they are done feeding, they will spend 10 to 15 minutes lip-licking and rubbing their head in the leaves to clean their mouth ... Unlike people have been led to believe, they do not have chunks of rotting flesh from their meals on their teeth, cultivating bacteria." They do have a slashing bite, which normally includes a dose of their neurotoxic venom and anticoagulant saliva. Komodo dragons do not wait for prey to die and track it at a distance, as vipers do; observations of them hunting deer, boar and in some cases buffalo reveal that they kill prey in less than half an hour during successful hunts, and usually in a matter of a few minutes, similar to large mammalian carnivores. The observation of prey dying of sepsis is instead likely based on misinterpretations of failed predation attempts caused by the natural instinct of water buffalo, which are not native to the islands where the Komodo dragon lives, to run into water after escaping an attack. The warm, faeces-filled water would then cause the infections. The study used samples from 16 captive dragons (10 adults and six neonates) from three US zoos.
Traditional markets, called pasars (including pasar malam and pasar pagi), are found across in Indonesia in both urban and rural areas. They face increasing competition from supermarkets as well as e-commerce companies like Shopee and Tokopedia. As of 2020, there are 12.3 million traders across 13,450 traditional markets in Indonesia. In 2016, the Indonesia government's policy to stabilise beef prices required importers to sell cheaper-priced meats in traditional markets instead of in supermarkets and hypermarkets. In Greater Jakarta, Indian buffalo meat is predominantly sold in traditional markets, with limited market penetration from supermarkets and hypermarkets as of 2018. In contrast, only 7% of consumers in Jakarta purchase Australian beef from supermarkets in 2018. In 2018, Indonesian market vendors that import goods expressed concerns over the decrease in value of the Indonesian rupiah. Traditional markets throughout Indonesia have undergone major renovations in the 2010s under a government program. In 2018, the first modernised traditional market opened in Jakarta with a laboratory as well as freezing and refrigeration facilities. Through June 2020, health protocols and mobility restrictions from the COVID-19 pandemic in Indonesia resulted in a 65% reduction in revenue for market traders, according to the Traditional Market Traders Association (IKAPPI). In mid-2020, traditional markets in several provinces accounted for several major clusters of COVID-19 cases.
== Additional sources == Birkhead T, Wimpenny J; Montgomerie B (2014). Ten Thousand Birds: Ornithology since Darwin. Princeton University Press. ISBN 978-0-691-15197-7. Chansigaud, Valerie (2009). History of Ornithology. London: New Holland Publishers. ISBN 978-1-84773-433-4. Gurney, John Henry (1921). "Early annals of ornithology". Nature. 108 (2713): 268. Bibcode:1921Natur.108..268.. doi:10.1038/108268a0. hdl:2027/coo.31924090299532. S2CID 4033666. Retrieved 19 November 2010. Newton, Alfred (1884). Ornithology. [S.l. : s.n.(Reprinted from the 1884 Encyclopædia Britannica) Podulka, Sandy; Eckhardt, Marie; Otis, Daniel (2001). "Birds and Humans: A Historical Perspective". In Podulka, Sandy; Rohrbaugh, Ronald W.; Bonney, Rick (eds.). Handbook of Bird Biology (2nd ed.). Ithaca, NY: Cornell Lab of Ornithology. pp. H1–H42. ISBN 978-0-938027-62-1. Walters, Michael (2005). A Concise History of Ornithology. New Haven, CT: Yale University Press. ISBN 978-1-84773-433-4.
Sources: en.wikipedia.org
The signal change manifests itself in an increase or decrease in the current (electrical) or in a change in the intensity or wavelength of the fluorescence emission (optical). Depending on the type of application, both electrical or optical signal transmission can be advantageous. For sensitive measurement of electronic changes, field-effect transistors (FET) are often used in which the flow of charges within the SWCNTs is measured. The FET structures allow easy on-chip integration and can be parallelized to detect multiple target analytes simultaneously. However, such sensors are more invasive for in vivo applications, as the entire device has to be inserted into the body. Optical detection with semiconducting SWCNTs is based on the radiative recombination of excitons in the near-infrared (NIR) by prior optical (fluorescence) or electrical excitation (electroluminescence). The emission in the NIR enables detection in the biological transparency window, where optical sensor applications benefit from reduced scattering and autofluorescence of biological samples and consequently a high signal-to-noise ratio. Compared to optical sensors in the UV or visible range, the penetration depth in biological tissue is also increased. In addition to the advantage of a contactless readout SWCNTs have excellent photostability, which enables long-term sensor applications. Furthermore, the nanoscale size of SWCNTs allows dense coating of surfaces which enables chemical imaging, e.g. of cellular release processes with high spatial and temporal resolution.
== C == C terminus - Can f 1 - cancer - candidate gene - Canonical sequence - cap - cap site - carbon-monoxide dehydrogenase (cytochrome b-561) - carboxyl terminus - carcinoma - carnitine dehydratase - carrier - carveol dehydrogenase - Catalog of MCA Control Patterns - CAT assay - CAT RNA-binding domain - catalase-related immune-responsive domain - CCAAT box - Cd2+-exporting ATPase - cDNA - cDNA clone - cDNA library - CDP-acylglycerol O-arachidonoyltransferase - cell - centimorgan - centromere - chain terminator - channel-conductance-controlling ATPase - chaperone protein - chlordecone reductase - chloroplast protein-transporting ATPase - cholestanetriol 26-monooxygenase - cholesterol 7alpha-monooxygenase - chromosome - chromosomal translocation - chromosome walking - CIROP gene - CIS - cistron - clone (genetics) - clone (noun) - clone (verb) - cloning - CmERG1 - coding sequence - coding strand - codon - codon usage bias - competent - complementary - conformational epitope - congenital - consensus sequence - conservative substitution - conserved - contig - coproporphyrinogen dehydrogenase - cortisone alpha-reductase - cosmid - costunolide synthase - CpG - craniosynostosis - crp domain - Cu2+-exporting ATPase - cyclodeaminase domain - cyclohexanol dehydrogenase - cyclopeptine synthase - cystic fibrosis - cytogenetic map - cytosine -
Also, the Export-Import Bank's lending limit was raised in 1958 from $5 billion to $7 billion, and the administration advocated in January 1959 an expanded "food for peace" program. The overall trend in U.S. government development-assistance activity in the 1950s is indicated by the change in the number of U.S. staff in field missions, which during Eisenhower's years in office from 1953 to 1961 rose from 2,839 to 6,387.
== Classification == A typical aptamer is a synthetically generated ligand exploiting the combinatorial diversity of DNA, RNA, XNA, or peptide to achieve strong, specific binding for a particular target molecule or family of target molecules. Aptamers are occasionally classified as "chemical antibodies" or "antibody mimics". However, most aptamers are small, with a molecular weight of 6-30 kDa, in contrast to the 150 kDa size of antibodies, and contain one binding site rather than the two matching antigen binding regions of a typical antibody.
Sources: en.wikipedia.org
== ISO 3650 – ISO 3999 == ISO 3650:1998 Geometrical Product Specifications (GPS) – Length standards – Gauge blocks ISO 3651 Determination of resistance to intergranular corrosion of stainless steels ISO 3651-1:1998 Austenitic and ferritic-austenitic (duplex) stainless steels — Corrosion test in nitric acid medium by measurement of loss in mass (Huey test) ISO 3651-2:1998 Ferritic, austenitic and ferritic-austenitic (duplex) stainless steels — Corrosion test in media containing sulfuric acid ISO 3651-3:2017 Determination of resistance to intergranular corrosion of stainless steels — Part 3: Corrosion test for low-Cr ferritic stainless steels ISO 3652:1975 Shipbuilding — Inland vessels — Rope reels [Withdrawn without replacement] ISO 3653:1978 Cinematography — Spindles for 8 mm Type S motion-picture projector reels/spools — Dimensions ISO 3654:1983 Cinematography — Motion-picture camera cartridge, 8-mm Type S, Model I — Cartridge-camera interface and take-up core drive — Dimensions and specifications [Withdrawn without replacement] ISO 3655:1986 Acceptance conditions for vertical turning and boring lathes with one or two columns and a single fixed or movable table — General introduction and testing of the accuracy ISO 3656:2011 Animal and vegetable fats and oils — Determination of ultraviolet absorbance expressed as specific UV extinction ISO 3657:2020 Animal and vegetable fats and oils — Determination of saponification value ISO 3658 Crude or liquid petroleum products — Determination of density and relative density — Graduated bicapillary pyknometer method [Draft merged into ISO 3838] ISO 3659:1977 Fruits and vegetables — Ripening after cold storage ISO 3660:1976 Fishing nets – Mounting and joining of netting – Terms and illustrations ISO 3661:1977 End-suction centrifugal pumps — Baseplate and installation dimensions ISO 3662:1976 Hydraulic fluid power — Pumps and motors — Geometric displacements ISO 3663:1976 Polyethylene (PE) pressure pipes and fittings, metric series — Dimensions of flanges ISO 3664:2009 Graphic technology and photography — Viewing conditions ISO 3665:2011 Photography — Intra-oral dental radiographic film and film packets — Manufacturer specifications ISO/TR 3666:1998 Viscosity of water ISO 3667 Aircraft — Dimensions of hermetically sealed contactors [Rejected draft] ISO 3668:2017 Paints and varnishes — Visual comparison of colour of paints ISO 3669:2020 Vacuum technology — Dimensions of knife-edge flanges ISO 3670:1979 Blanks for plug gauges and handles (taper lock and trilock) and ring gauges — Design and general dimensions [Withdrawn without replacement] ISO 3671:1976 Plastics — Aminoplastic moulding materials — Determination of volatile matter ISO 3672 Plastics — Unsaturated-polyester resins (UP-R) ISO 3672-1:2000 Part 1: Designation system ISO 3672-2:2000 Part 2: Preparation of test specimens and determination of properties ISO 3673 Plastics — Epoxy resins ISO 3673-1:1996 Part 1: Designation ISO 3673-2:2012 Part 2: Preparation of test specimens and determination of properties of crosslinked epoxy resins ISO 3674:1976 Shipbuilding — Inland vessels — Deck rail [Withdrawn without replacement] ISO 3675:1998 Crude petroleum and liquid petroleum products — Laboratory determination of density — Hydrometer method ISO 3676:2012 Packaging – Complete, filled transport packages and unit loads – Unit load dimensions ISO 3677:2016 Filler metal for soldering and brazing — Designation ISO 3678:1976 Paints and varnishes — Print-free test [Withdrawn: replaced with ISO 9117-6] ISO 3679:2015 Determination of flash no-flash and flash point — Rapid equilibrium closed cup method ISO 3680:2004 Determination of flash/no flash — Rapid equilibrium closed cup method [Withdrawn: replaced with ISO 3679] ISO 3681:2018 Binders for paints and varnishes — Determination of saponification value — Titrimetric method ISO 3682:1996 Binders for paints and varnishes — Determination of acid value — Titrimetric method [Withdrawn: replaced with ISO 2114] ISO 3683:1978 Soft soldered joints — Determination of shear strength [Withdrawn: replaced with ISO 5187] ISO 3684:1990 Conveyor belts — Determination of minimum pulley diameters ISO 3685:1993 Tool-life testing with single-point turning tools ISO 3686: Test conditions for high accuracy turret and single spindle coordinate drilling and boring machines with table of fixed height with vertical spindle — Testing of the accuracy ISO 3686-1:2000 Part 1: Single column type machines ISO 3686-2:2000 Part 2: Portal type machines with moving table ISO 3687:1976 Paper and board — Determination of air resistance (Gurley) [Withdrawn without replacement] ISO 3688:1999 Pulps — Preparation of laboratory sheets for the measurement of diffuse blue reflectance factor (ISO brightness) ISO 3689:1983 Paper and board — Determination of bursting strength after immersion in water ISO 3690:2018 Welding and allied processes — Determination of hydrogen content in arc weld metal ISO 3691 Industrial trucks — Safety requirements and verification ISO 3691-1:2011 Part 1: Self-propelled industrial trucks, other than driverless trucks, variable-reach trucks and burden-carrier trucks ISO 3691-2:2016 Part 2: Self-propelled variable-reach trucks ISO 3691-3:2016 Part 3: Additional requirements for trucks with elevating operator position and trucks specifically designed to travel with elevated loads ISO 3691-4:2020 Part 4: Driverless industrial trucks and their systems ISO 3691-5:2014 Part 5: Pedestrian-propelled trucks ISO 3691-6:2021 Part 6: Burden and personnel carriers ISO/TS 3691-7:2011 Part 7: Regional requirements for countries within the European Community [Withdrawn without replacement] ISO 3692:1976 Information processing – Reels and cores for 25,4 mm (1 in) perforated paper tape for information interchange – Dimensions [Withdrawn without replacement] ISO 3693:1977 Nitric acid for industrial use — Determination of chloride ions content — Potentiometric method [Withdrawn without replacement] ISO 3694:1977 Ammonium sulphate for industrial use — Determination of chloride ions content — Potentiometric method [Withdrawn without replacement] ISO 3695:1977 Ammonium nitrate for industrial use — Determination of chloride ions content — Potentiometric method [Withdrawn without replacement] ISO 3696:1987 Water for analytical laboratory use — Specification and test methods ISO 3697:1976 Sodium hydroxide for industrial use — Determination of calcium and magnesium contents — Flame atomic absorption method [Withdrawn without replacement] ISO 3698:1976 Potassium hydroxide for industrial use — Determination of calcium and magnesium contents — Flame atomic absorption method [Withdrawn without replacement] ISO 3699:1976 Anhydrous hydrogen fluoride for industrial use — Determination of water content — Karl Fischer method ISO 3700:1980 Anhydrous hydrogen fluoride for industrial use — Determination of water content — Conductimetric method [Withdrawn without replacement] ISO 3701:1976 Anhydrous hydrogen fluoride for industrial use — Determination of hexafluorosilicic acid content — Reduced molybdosilicate photometric method [Withdrawn without replacement] ISO 3702:1976 Anhydrous hydrogen fluoride for industrial use — Determination of sulphur dioxide content — Iodometric method [Withdrawn without replacement] ISO 3703:1993 Acid-grade and ceramic-grade fluorspar — Determination of flotation agents [Withdrawn without replacement] ISO 3704:1976 Sulphur for industrial use — Determination of acidity — Titrimetric method ISO 3705:1976 Sulphur for industrial use — Determination of arsenic content — Silver diethyldithiocarbamate photometric method ISO 3706:1976 Phosphoric acid for industrial use (including foodstuffs) — Determination of total phosphorus (V) oxide content — Quinoline phosphomolybdate gravimetric method ISO 3707:1976 Phosphoric acid for industrial use (including foodstuffs) — Determination of calcium content — Flame atomic absorption method [Withdrawn without replacement] ISO 3708:1976 Phosphoric acid for industrial use (including foodstuffs) — Determination of chloride content — Potentiometric method [Withdrawn without replacement] ISO 3709:1976 Phosphoric acid for industrial use (including foodstuffs) — Determination of oxides of nitrogen content — 3,4- Xylenol spectrophotometric method [Withdrawn without replacement] ISO 3710:1990 Lead chrome green pigments — Specifications and methods of test [Withdrawn without replacement] ISO 3711:1990 Lead chromate pigments and lead chromate-molybdate pigments — Specifications and methods of test ISO 3713:1987 Ferroalloys – Sampling and preparation of samples – General rules ISO 3714:1980 Oil of pennyroyal [Withdrawn without replacement] ISO 3715 Ships and marine technology – Propulsion plants for ships ISO 3715-1:2002 Part 1: Vocabulary for geometry of propellers ISO 3715-2:2001 Part 2: Vocabulary for controllable-pitch propeller plants ISO 3716:2021 Hydrometry – Functional requirements and characteristics of suspended-sediment samplers ISO/TR 3717:1975 Textile glass — Mats and woven fabrics — Determination of wet-out time through resin [Withdrawn without replacement] ISO/TR 3718:1975 Textile glass — Determination of wet-through time through resin [Withdrawn without replacement] ISO 3719:1994 Mechanical vibration — Symbols for balancing machines and associated instrumentation [Withdrawn without replacement] ISO 3720:2011 Black tea — Definition and basic requirements ISO 3721:2023 Information technology — Computer graphics, image processing and environmental data representation — Information model for Mixed and Augmented Reality Contents - Core Objects and Attributes [original draft was Rigid cellular practice — classification and designation] ISO 3722:1976 Hydraulic fluid power — Fluid sample containers — Qualifying and controlling cleaning methods ISO 3723:2015 Hydraulic fluid power — Filter elements — Method for end load test ISO 3724:2007 Hydraulic fluid power — Filter elements — Determination of resistance to flow fatigue using particulate contaminant ISO 3725:2023 Ships and marine technology — Aquatic nuisance species — Methods for evaluating the performance of compliance monitoring devices for ballast water discharges [original draft was Statistics – Symbols, merged into ISO 3534] ISO 3726:1983 Instant coffee — Determination of loss in mass at 70 degrees C under reduced pressure ISO 3727 Butter — Determination of moisture, non-fat solids and fat contents ISO 3727-1:2001 Part 1: Determination of moisture content (Reference method) ISO 3727-2:2001 Part 2: Determination of non-fat solids content (Reference method) ISO 3727-3:2003 Part 3: Calculation of fat content ISO 3728:2004 Ice-cream and milk ice — Determination of total solids content (Reference method) ISO 3729:1976 Fibre building boards — Determination of surface stability [Withdrawn without replacement] ISO 3730:2012 Shipbuilding and marine structures — Mooring winches ISO 3731:2003 Road vehicles — Connectors for the electrical connection of towing and towed vehicles — 7-pole connector type 24 S (supplementary) for vehicles with 24 V nominal supply voltage ISO 3732:2003 Road vehicles — Connectors for the electrical connection of towing and towed vehicles — 7-pole connector type 12 S (supplementary) for vehicles with 12 V nominal supply voltage ISO 3733:1999 Petroleum products and bituminous materials — Determination of water — Distillation method ISO 3734:1997 Petroleum products — Determination of water and sediment in residual fuel oils — Centrifuge method ISO 3735:1999 Crude petroleum and fuel oils — Determination of sediment — Extraction method ISO 3736 Digital fitting — Service process [original draft was Standard atmospheres for conditioning and/or testing — Specifications was numbered ISO 554 to replace ISO/R 554] ISO/TD 3736-1:2022 Part 1: Ready-to-wear clothing online and off-line ISO/TD 3736-2:2022 Part 2: Customized clothing online and off-line ISO 3737:1976 Agricultural tractors and self-propelled machines — Test method for enclosure pressurization systems [Withdrawn: replaced with ISO 14269-(1-5)] ISO 3738 Hardmetals — Rockwell hardness test (scale A) ISO 3738-1:1982 Part 1: Test method ISO 3738-2:1988 Part 2: Preparation and calibration of standard test blocks ISO 3739 Industrial tyres and rims ISO 3739-1:2007 Part 1: Pneumatic tyres (metric series) on 5 degrees tapered or flat base rims ISO 3739-2:2021 Part 2: Pneumatic tyres (metric series) on 5 degrees tapered or flat base rims — Load ratings ISO 3739-3:2021 Part 3: Rims ISO 3740:2019 Acoustics – Determination of sound power levels of noise sources – Guidelines for the use of basic standards ISO 3741:2010 Acoustics – Determination of sound power levels and sound energy levels of noise sources using sound pressure – Precision methods for reverberation test rooms ISO 3742:1988 Acoustics — Determination of sound power levels of noise sources — Precision methods for discrete-frequency and narrow-band sources in reverberation rooms [Withdrawn: replaced with ISO 3741] ISO 3743 Acoustics – Determination of sound power levels and sound energy levels of noise sources using sound pressure – Engineering methods for small movable sources in reverberant fields ISO 3743-1:2010 Part 1: Comparison method for a hard-walled test room ISO 3743-2:2018 Part 2: Methods for special reverberation test rooms ISO 3744:2010 Acoustics – Determination of sound power levels and sound energy levels of noise sources using sound pressure – Engineering methods for an essentially free field over a reflecting plane ISO 3745:2012 Acoustics – Determination of sound power levels and sound energy levels of noise sources using sound pressure – Precision methods for anechoic rooms and hemi-anechoic rooms ISO 3746:2010 Acoustics – Determination of sound power levels and sound energy levels of noise sources using sound pressure – Survey method using an enveloping measurement surface over a reflecting plane ISO 3747:2010 Acoustics – Determination of sound power levels and sound energy levels of noise sources using sound pressure – Engineering/survey methods for use in situ in a reverberant environment ISO 3748 Acoustics — Determination of sound power levels of noise sources — Engineering method for small, nearly omnidirectional sources under free-field conditions over a reflecting plane [Rejected draft] ISO 3749:2022 Glass syringes — Determination of extractable tungsten [Original draft with this number unknown] ISO 3750:2006 Zinc alloys — Determination of magnesium content — Flame atomic absorption spectrometric method ISO 3751:1976 Zinc ingots — Selection and preparation of samples for chemical analysis [Withdrawn: replaced with ISO 20081] ISO 3752:1976 Zinc alloy ingots — Selection and preparation of samples for chemical analysis [Withdrawn: replaced with ISO 20081] ISO 3753:1977 Vacuum technology — Graphical symbols [Withdrawn without replacement] ISO 3754:1976 Steel — Determination of effective depth of hardening after flame or induction hardening [Withdrawn: replaced with ISO 18203] ISO 3755:1991 Cast carbon steels for general engineering purposes [Withdrawn: replaced with ISO 14737] ISO 3756:1976 Oil of cubeb ISO 3757:2002 Oil of patchouli (Pogostemon cablin (Blanco) Benth.) ISO 3758:2012 Textiles — Care labelling code using symbols ISO 3759:2011 Textiles — Preparation, marking and measuring of fabric specimens and garments in tests for determination of dimensional change ISO 3760:2002 Oil of celery seed (Apium graveolens L.) ISO 3761:2005 Oil of rosewood, Brazilian type (Aniba rosaeodora Ducke or Aniba parviflora (Meisn.) Mez.) ISO 3762:1979 Paper — Preparation of a letterpress print for test purposes [Withdrawn without replacement] ISO 3763:1976 Wrought steels — Macroscopic methods for assessing the content of non-metallic inclusions ISO 3764:2016 Timekeeping instruments — Movements — Types, dimensions and nomenclature ISO 3765:1998 Timekeeping instruments — Wristwatches — Dimensions of bracelet-to-case fastening elements ISO 3766:2003 Construction drawings – Simplified representation of concrete reinforcement ISO 3767 Tractors, machinery for agriculture and forestry, powered lawn and garden equipment – Symbols for operator controls and other displays ISO 3767-1:2016 Part 1: Common symbols ISO 3767-2:2016 Part 2: Symbols for agricultural tractors and machinery ISO 3767-3:2016 Part 3: Symbols for powered lawn and garden equipment ISO 3767-4:2016 Part 4: Symbols for forestry machinery ISO 3767-5:2016 Part 5: Symbols for manual portable forestry machines ISO 3768:1976 Metallic coatings — Neutral salt spray test (NSS test) [Withdrawn: replaced with ISO 9227] ISO 3769:1976 Metallic coatings — Neutral salt spray test (NSS test) [Withdrawn: replaced with ISO 9227] ISO 3770:1976 Metallic coatings — Copper-accelerated acetic acid salt spray test (CASS test) [Withdrawn: replaced with ISO 9227] ISO 3771:2011 Petroleum products — Determination of base number — Perchloric acid potentiometric titration method ISO 3772:2000 Photography — Rolls of sensitized material for the pre-press industry — Dimensions and related requirements ISO 3773:1983 Cinematography — Tape splices for 8 mm Type S motion-picture film for projector use — Dimensions ISO 3774:1988 Cinematography — 35 mm motion-picture film perforated 8 mm Type S (1-3-5-7-0) and (1-0) — Cutting and perforating dimensions ISO 3775:1990 Cinematography — Printed 8 mm Type S image area on 16 mm motion-picture film perforated 8 mm Type S (1-3) — Position and dimensions [Withdrawn without replacement] ISO 3776 Tractors and machinery for agriculture — Seat belts ISO 3776-1:2006 Part 1: Anchorage location requirements ISO 3776-2:2013 Part 2: Anchorage strength requirements ISO 3776-3:2009 Part 3: Requirements for assemblies ISO 3777:1976 Radiographic inspection of resistance spot welds for aluminium and its alloys — Recommended practice [Withdrawn without replacement] ISO/TR 3778:1987 Agricultural tractors — Maximum actuating forces required to operate controls [Withdrawn: replaced with ISO 15077] ISO 3779:2009 Road vehicles — Vehicle identification number (VIN) — Content and structure ISO 3780:2009 Road vehicles — World manufacturer identifier (WMI) code ISO 3781:2011 Paper and board — Determination of tensile strength after immersion in water ISO 3782:1980 Paper and board — Determination of resistance to picking — Accelerating speed method using the IGT tester (Pendulum or spring model) [Withdrawn without replacement] ISO 3783:2006 Paper and board — Determination of resistance to picking — Accelerated speed method using the IGT-type tester (electric model) ISO 3784:1976 Road vehicles — Measurement of impact velocity in collision tests ISO 3785:2006 Metallic materials — Designation of test specimen axes in relation to product texture ISO 3786:1975 Shipbuilding — Inland navigation towing hooks — Scale of tractive efforts [Withdrawn without replacement] ISO 3787:1976 Wood — Test methods — Determination of ultimate stress in compression parallel to grain [Withdrawn: replaced with ISO 13061-167] ISO/IEC 3788:1990 Information processing – 9-track, 12,7 mm (0,5 in) wide magnetic tape for information interchange using phase encoding at 126 ftpmm (3 200 ftpi), 63 cpmm (1 600 cpi) ISO 3789 Tractors, machinery for agriculture and forestry, powered lawn and garden equipment — Location and method of operation of operator controls ISO 3789-1:1982 Part 1: Common controls [Withdrawn: replaced with ISO 15077] ISO 3789-2:1982 Part 2: Controls for agricultural tractors and machinery [Withdrawn: replaced with ISO 15077] ISO 3790:1976 Fishing nets — Determination of elongation of netting yarns ISO 3791:1976 Office machines and data processing equipment – Keyboard layouts for numeric applications ISO 3792:1976 Adding machines – Layout of function keyboard ISO 3793:1976 Essential oils — Estimation of primary and secondary free alcohols content by acetylation in pyridine [Withdrawn without replacement] ISO 3794:1976 Essential oils (containing tertiary alcohols) — Estimation of free alcohols content by determination of ester value after acetylation ISO 3795:1989 Road vehicles, and tractors and machinery for agriculture and forestry — Determination of burning behaviour of interior materials ISO 3796:1999 Ships and marine technology — Clear openings for external single-leaf doors ISO 3797:1976 Shipbuilding — Vertical steel ladders ISO 3798:1976 Tinplate and blackplate — Minimum packaging requirements [Withdrawn without replacement] ISO 3799:1976 Textile machinery and accessories — Hydraulic lubricating fittings for textile machinery [Withdrawn without replacement] ISO 3800:1993 Threaded fasteners — Axial load fatigue testing — Test methods and evaluation of results ISO 3801:1977 Textiles — Woven fabrics — Determination of mass per unit length and mass per unit area ISO 3802:1976 Information processing – General purpose reels with 8 mm (5/16 in) centre hole for magnetic tape for interchange instrumentation applications ISO 3803:1984 Road vehicles — Hydraulic pressure test connection for braking equipment ISO 3804:1977 Plywood — Determination of dimensions of test pieces [Withdrawn: replaced with ISO 9424] ISO 3805:1977 Plywood — Determination of density [Withdrawn: replaced with ISO 9427] ISO 3806:1977 Plywood — Determination of moisture content [Withdrawn: replaced with ISO 9425] ISO 3807:2013 Gas cylinders — Acetylene cylinders — Basic requirements and type testing ISO 3808:2002 Road vehicles — Unscreened high-voltage ignition cables — General specifications, test methods and requirements ISO 3809:2004 Oil of lime (cold pressed), Mexican type (Citrus aurantifolia (Christm.) Swingle), obtained by mechanical means ISO 3810:1987 Floor tiles of agglomerated cork — Methods of test ISO 3811:1979 Meat and meat products — Detection and enumeration of presumptive coliform bacteria and presumptive Escherichia coli — (Reference method) [Withdrawn: replaced with ISO 4831, ISO 4832, and ISO 7251] ISO 3812:1976 Essential oils of geranium and rose — Determination of ester value after hot formylation ISO 3813:2004 Resilient floor coverings — Cork floor tiles — Specification [Withdrawn without replacement] ISO/TS 3814:2014 Standard tests for measuring reaction-to-fire of products and materials — Their development and application ISO 3815 Zinc and zinc alloys ISO 3815-1:2005 Part 1: Analysis of solid samples by optical emission spectrometry ISO 3815-2:2005 Part 2: Analysis by inductively coupled plasma optical emission spectrometry ISO 3816:1976 Zinc ingots — Selection and preparation of samples for spectrographic analysis [Withdrawn: replaced with ISO 20081] ISO 3817:1976 Zinc alloy ingots — Selection and preparation of samples for spectrographic analysis [Withdrawn: replaced with ISO 20081] ISO/TR 3818:1977 Ropes and cordage — Rope assemblies used in slinging — Safe working loads [Withdrawn without replacement] ISO 3819:2015 Laboratory glassware – Beakers ISO 3820:1978 Cinematography — Sprockets for 8 mm Type S motion-picture film — Dimensions and design ISO 3821:2019 Gas welding equipment — Rubber hoses for welding, cutting and allied processes ISO 3822 Acoustics – Laboratory tests on noise emission from appliances and equipment used in water supply installations ISO 3822-1:1999 Part 1: Method of measurement ISO 3822-2:1995 Part 2: Mounting and operating conditions for draw-off taps and mixing valves ISO 3822-3:2018 Part 3: Mounting and operating conditions for in-line valves and appliances ISO 3822-4:1997 Part 4: Mounting and operating conditions for special appliances ISO 3823 Dental rotary instruments — Burs ISO 3823-1:1997 Part 1: Steel and carbide burs ISO 3823-2:2003 Part 2: Finishing burs ISO 3824:1984 Dental silicophosphate cement (hand-mixed) [Withdrawn: replaced with ISO 9917] ISO 3825:1977 Glass transfusion bottles for medical use — Chemical resistance [Withdrawn without replacement] ISO 3826 Plastics collapsible containers for human blood and blood components ISO 3826-1:2013 Part 1: Conventional containers ISO 3826-2:2008 Part 2: Graphical symbols for use on labels and instruction leaflets ISO 3826-3:2006 Part 3: Blood bag systems with integrated features ISO 3826-4:2015 Part 4: Aphaeresis blood bag systems with integrated features ISO 3827 Shipbuilding — Co-ordination of dimensions in ships' accommodation ISO 3827-1:1977 Part 1: Principles of dimensional co-ordination ISO 3827-2:1977 Part 2: Glossary of terms ISO 3827-3:1977 Part 3: Co-ordinating sizes for components and assemblies ISO 3827-4:1977 Part 4: Controlling dimensions ISO 3827-5:1979 Part 5: Co-ordinating sizes for key components ISO 3828:2008 Shipbuilding and marine structures – Deck machinery – Vocabulary and symbols ISO 3829 Petroleum products – Determination of density and relative density – Jaulmes pyknometer method [Rejected draft] ISO 3830:1993 Petroleum products — Determination of lead content of gasoline — Iodine monochloride method ISO 3831:1979 Timekeeping instruments — Classification and numbering system and nomenclature of components for watches and clocks [Withdrawn without replacement] ISO 3832:2002 Passenger cars — Luggage compartments — Method of measuring reference volume ISO 3833:1977 Road vehicles – Types – Terms and definitions ISO 3834 Quality requirements for fusion welding of metallic materials ISO 3834-1:2021 Part 1: Criteria for the selection of the appropriate level of quality requirements ISO 3834-2:2021 Part 2: Comprehensive quality requirements ISO 3834-3:2021 Part 3: Standard quality requirements ISO 3834-4:2021 Part 4: Elementary quality requirements ISO 3834-5:2021 Part 5: Documents with which it is necessary to conform to claim conformity to the quality requirements of ISO 3834-2, ISO 3834-3 or ISO 3834-4 ISO 3834-6:2024 Part 6: Guidelines on implementing the ISO 3834 series ISO 3835 Equipment for vine cultivation and wine making – Vocabulary ISO 3835-1:1976 (No part title) ISO 3835-2:1977 (No part title) [Withdrawn without replacement] ISO 3835-3:1980 (No part title) ISO 3835-4:1981 (No part title) ISO 3835-5:1982 (No part title) [Withdrawn without replacement] ISO/TR 3836:1978 Shoe sizes — System of width grading (for use in the Mondopoint system) [Withdrawn without replacement] ISO 3837:1993 Liquid petroleum products — Determination of hydrocarbon types — Fluorescent indicator adsorption method ISO 3838:2004 Crude petroleum and liquid or solid petroleum products — Determination of density or relative density — Capillary-stoppered pyknometer and graduated bicapillary pyknometer methods ISO 3839:1996 Petroleum products — Determination of bromine number of distillates and aliphatic olefins — Electrometric method ISO 3840:1976 Petroleum distillates — Determination of olefinic plus aromatic hydrocarbons content [Withdrawn without replacement] ISO 3841:1977 Petroleum waxes — Determination of melting point (cooling curve) [Withdrawn without replacement] ISO 3842:2006 Road vehicles — Fifth wheels — Interchangeability ISO 3843 Dentistry — Dental attachments — Measurement of placement and removal forces [Under development; original draft named ISO 2135 as it was a revision of ISO/R 2135] ISO 3844:1975 Shoe sizes — Method of marking [Withdrawn: replaced with ISO 9407] ISO 3845:2024 Oil and gas industries including lower carbon energy — Full ring ovalization test method for the evaluation of the cracking resistance of steel line pipe in sour service [original draft was Petroleum and natural gas industries — High-test steel line pipe] ISO 3846:2008 Hydrometry – Open channel flow measurement using rectangular broad-crested weirs ISO 3847:1977 Liquid flow measurement in open channels by weirs and flumes – End-depth method for estimation of flow in rectangular channels with a free overfall [Withdrawn: replaced with ISO 18481] ISO 3848:2016 Essential oil of citronella, Java type ISO 3849:2003 Oil of citronella, Sri Lankan type (Cymbopogon nardus (L.) W. Watson var. lenabatu Stapf.) ISO 3850:2004 Resilient floor coverings – Determination of apparent density of composition cork ISO 3851:1977 Capsulated dental silicate and silico-phosphate filling materials [Withdrawn: replaced with ISO 9917] ISO 3852:2007 Iron ores for blast furnace and direct reduction feedstocks — Determination of bulk density ISO 3853:1994 Road vehicles — Towing vehicle coupling device to tow caravans or light trailers — Mechanical strength test ISO 3854:1976 Road vehicles — Caravans and light trailers — Vacuum braking — Measurement of reaction time [Withdrawn without replacement] ISO 3855:1977 Milling cutters – Nomenclature ISO 3856 Paints and varnishes — Determination of "soluble" metal content ISO 3856-1:1984 Part 1: Determination of lead content — Flame atomic absorption spectrometric method and dithizone spectrophotometric method ISO 3856-2:1984 Part 2: Determination of antimony content — Flame atomic absorption spectrometric method and Rhodamine B spectrophotometric method ISO 3856-3:1984 Part 3: Determination of barium content — Flame atomic emission spectrometric method ISO 3856-4:1984 Part 4: Determination of cadmium content — Flame atomic absorption spectrometric method and polarographic method ISO 3856-5:1984 Part 5: Determination of hexavalent chromium content of the pigment portion of the liquid paint or the paint in powder form — Diphenylcarbazide spectrophotometric method ISO 3856-6:1984 Part 6: Determination of total chromium content of the liquid portion of the paint — Flame atomic absorption spectrometric method ISO 3856-7:1984 Part 7: Determination of mercury content of the pigment portion of the paint and of the liquid portion of water-dilutable paints — Flameless atomic absorption spectrometric method ISO 3857 Compressors, pneumatic tools and machines – Vocabulary ISO 3857-1:1977 Part 1: General ISO 3857-2:1977 Part 2: Compressors ISO 3857-3:1989 Part 3: Pneumatic tools and machines ISO 3857-4:2012 Part 4: Air treatment ISO 3858:2018 Rubber compounding ingredients — Carbon black — Determination of light transmittance of toluene extract ISO 3859:2000 Inverse dovetail cutters and dovetail cutters with cylindrical shanks ISO 3860:2011 Bore cutters with key drive — Form milling cutters with constant profile ISO 3861:2005 Rubber hoses and hose assemblies for sand and grit blasting — Specification ISO 3862:2020 Rubber hoses and hose assemblies — Rubber-covered spiral-wire-reinforced hydraulic types for oil-based or water-based fluids — Specification ISO 3863:1989 Cylindrical cork stoppers — Dimensional characteristics, sampling, packaging and marking [Withdrawn without replacement] ISO 3864 Graphical symbols – Safety colours and safety signs ISO 3865:2020 Rubber, vulcanized or thermoplastic — Methods of test for staining in contact with organic material ISO 3866:1977 Office machines and printing machines used for information processing – Widths of fabric printing ribbons on spools exceeding 19 mm ISO 3867:2017 Composition cork — Expansion joint fillers — Test methods ISO 3868:1976 Metallic and other non-organic coatings — Measurement of coating thicknesses — Fizeau multiple-beam interferometry method ISO 3869:2017 Agglomerated cork — Expansion joint fillers — Specifications, packaging and marking ISO 3870:1976 Conveyor belts (fabric carcass), with length between pulley centres up to 300 m, for loose bulk materials — Adjustment of take-up device [Withdrawn without replacement] ISO 3871:2000 Road vehicles — Labelling of containers for petroleum-based or non-petroleum-based brake fluid ISO 3872:1976 Graphic technology — Sheet-fed printing machines — Range of sizes [Withdrawn without replacement] ISO 3873:1977 Industrial safety helmets ISO 3874:2017 Series 1 freight containers — Handling and securing ISO 3875:2020 Machine tools — Test conditions for external cylindrical centreless grinding machines — Testing of the accuracy ISO 3876:1986 Shipbuilding — Inland vessels — Hand-holes [Withdrawn without replacement] ISO 3877 Tyres, valves and tubes – List of equivalent terms ISO 3877-1:1997 Part 1: Tyres ISO 3877-2:1997 Part 2: Tyre valves ISO 3877-3:1978 Part 3: Tubes ISO 3877-4:1984 Part 4: Solid tyres ISO 3878:1983 Hardmetals — Vickers hardness test [Withdrawn without replacement] ISO 3879:1977 Welded joints — Recommended practice for liquid penetrant testing [Withdrawn: replaced with ISO 3452] ISO 3880 Building construction – Stairs – Vocabulary ISO 3880-1:1977 [Withdrawn without replacement] ISO 3881:1977 Building construction — Modular co-ordination — Stairs and stair openings — Co-ordinating dimensions ISO 3882:2003 Metallic and other inorganic coatings — Review of methods of measurement of thickness ISO 3883:1977 Office machines – Line and character capacity of address masters ISO 3884:2025 Solid recovered fuels — Methods for the determination of the content of elements (Al, Ca, Fe, K, Mg, Na, P, S, Si, Ti, As, Ba, Be, Cd, Co, Cr, Cu, Hg, Mo, Mn, Ni, Pb, Sb, Se, Sn, Tl, V, Zn) [Original draft was Plastic identification card 1] ISO 3885 Solid recovered fuels — Determination of halogens and sulfur by oxidative pyrohydrolytic combustion followed by ion chromatography [under development; original draft with this number unknown ISO 3886:1986 Iron ores — Determination of manganese content — Periodate spectrophotometric method [Withdrawn: replaced with ISO 9682-2] ISO 3887:2007 Steels — Determination of the depth of decarburization ISO 3888 Passenger cars — Test track for a severe lane-change manoeuvre ISO 3888-1:2018 Part 1: Double lane-change ISO 3888-2:2011 Part 2: Obstacle avoidance ISO 3889:2006 Milk and milk products — Specification of Mojonnier-type fat extraction flasks ISO 3890 Milk and milk products — Determination of residues of organochlorine compounds (pesticides) ISO 3890-1:2009 Part 1: General considerations and extraction methods ISO 3890-2:2009 Part 2: Test methods for crude extract purification and confirmation ISO 3891:1978 Acoustics — Procedure for describing aircraft noise heard on the ground [Withdrawn without replacement] ISO 3892:2000 Conversion coatings on metallic materials — Determination of coating mass per unit area — Gravimetric methods ISO 3893:1977 Concrete — Classification by compressive strength [Withdrawn without replacement] ISO 3894:2015 Road vehicles — Wheels/rims for commercial vehicles — Test methods ISO 3895:1986 Road vehicles — Screened and waterproof spark-plug and its connection — Type 2 ISO 3896:1986 Road vehicles — Screened and waterproof spark-plug and its connection — Type 3 ISO 3897:1997 Photography — Processed photographic plates — Storage practices [Withdrawn: replaced with ISO 18918] ISO 3898:2013 Bases for design of structures — Names and symbols of physical quantities and generic quantities ISO 3899:2005 Rubber — Nitrile latex — Determination of residual acrylonitrile content ISO 3900:1995 Rubber — Nitrile latex — Determination of bound acrylonitrile content ISO 3901:2019 Information and documentation – International Standard Recording Code (ISRC) ISO 3902:1990 Shipbuilding and marine structures — Gaskets for rectangular windows and side scuttles ISO 3903:2012 Ships and marine technology — Ships' ordinary rectangular windows ISO 3904:1990 Shipbuilding and marine structures — Clear-view screens ISO 3905:1980 Paints and varnishes — Determination of contrast ratio (opacity) of light coloured paints at a fixed spreading rate (using black and white charts) [Withdrawn: replaced with ISO 6504-3] ISO 3906:1980 Paints and varnishes — Determination of contrast ratio (opacity) of light coloured paints at a fixed spreading rate (using polyester film) [Withdrawn: replaced with ISO 6504-3] ISO 3907:2009 Hardmetals — Determination of total carbon — Gravimetric method ISO 3908:2009 Hardmetals — Determination of insoluble (free) carbon — Gravimetric method ISO 3909:1976 Hardmetals — Determination of cobalt — Potentiometric method ISO 3910:1983 Rubber boots, unlined moulded [Withdrawn without replacement] ISO 3911:2021 Wheels and rims for pneumatic tyres – Vocabulary, designation and marking ISO 3912:1977 Woodruff keys and keyways [Withdrawn without replacement] ISO 3913:1977 Shipbuilding — Welded steel bollards ISO 3914 Textile machinery and accessories — Cylindrical tubes ISO 3914-1:1994 Part 1: Recommended main dimensions ISO 3914-2:1994 Part 2: Dimensions, tolerances and designation of tubes for open-end spinning machines ISO 3914-3:1994 Part 3: Dimensions, tolerances and designation of tubes for tape yarns ISO 3914-4:1994 Part 4: Dimensions, tolerances and designation of tubes for textured yarns [Withdrawn without replacement] ISO 3914-5:1994 Part 5: Dimensions, tolerances and designation of tubes for continuous spin-drawn synthetic filament yarns [Withdrawn without replacement] ISO 3914-6:1994 Part 6: Dimensions, tolerances and designation of tubes for cross-wound packages in winding and twisting [Withdrawn without replacement] ISO 3914-7:1994 Part 7: Dimensions, tolerances and designation of perforated tubes for cheese dyeing ISO 3915:2022 Plastics — Measurement of resistivity of conductive plastics ISO 3916:1977 Shipbuilding — Inland navigation — Rope tubs [Withdrawn without replacement] ISO 3917:2016 Road vehicles — Safety glazing materials — Test methods for resistance to radiation, high temperature, humidity, fire and simulated weathering ISO 3918:2007 Milking machine installations – Vocabulary ISO 3919:2005 Coated abrasives — Flap wheels with shaft ISO 3920:1976 Honing stones of square section — Designation and dimensions [Withdrawn: replaced with ISO 603-(1-16)] ISO 3921:1976 Honing stones of rectangular section — Designation and dimensions [Withdrawn: replaced with ISO 603-(1-16)] ISO 3922:1978 Continuous mechanical handling equipment — Rotary vane feeder — Dimensional specifications [Withdrawn without replacement] ISO 3923 Metallic powders — Determination of apparent density ISO 3923-1:2018 Part 1: Funnel method ISO 3923-2:1981 Part 2: Scott volumeter method ISO 3923-3:1986 Part 3: Oscillating funnel method [Withdrawn without replacement] ISO 3924:2019 Petroleum products — Determination of boiling range distribution — Gas chromatography method ISO 3925:2014 Unsealed radioactive substances — Identification and documentation ISO 3926:1980 Shipbuilding — Inland navigation — Couplings for oil and fuel reception — Mating dimensions [Withdrawn without replacement] ISO 3927:2017 Metallic powders, excluding powders for hardmetals — Determination of compressibility in uniaxial compression ISO 3928:2016 Sintered metal materials, excluding hardmetals — Fatigue test pieces ISO 3929:2003 Road vehicles — Measurement methods for exhaust gas emissions during inspection or maintenance ISO 3930:2000 Instruments for measuring vehicle exhaust emissions [Withdrawn without replacement] ISO 3931 Fibre building boards – Determination of transversal internal bond [Rejected draft] ISO 3932:1976 Textiles — Woven fabrics — Measurement of width of pieces [Withdrawn: replaced with ISO 22198] ISO 3933:1976 Textiles — Woven fabrics — Measurement of length of pieces [Withdrawn: replaced with ISO 22198] ISO 3934:2021 Rubber, vulcanized and thermoplastic — Preformed gaskets used in buildings — Classification, specifications and test methods ISO 3935:1977 Shipbuilding — Inland navigation — Fire-fighting water system — Pressures [Withdrawn without replacement] ISO 3936:1993 Reduction sleeves with tenon drive with external and internal 7/24 taper — Dimensions ISO 3937 Cutter arbors with tenon drive ISO 3937-1:2008 Part 1: Dimensions of Morse taper ISO 3937-2:2008 Part 2: Dimensions of 7/24 taper ISO 3937-3:2008 Part 3: Dimensions of hollow taper interface with flange contact surface ISO 3938:1986 Hydraulic fluid power — Contamination analysis — Method for reporting analysis data [Withdrawn without replacement] ISO 3939:1977 Fluid power systems and components — Multiple lip packing sets — Methods for measuring stack heights ISO 3940:1977 Tapered die-sinking cutters with parallel shanks ISO 3941:1977 Classification of fires ISO 3942:1976 Photographic grade sodium carbonate, monohydrate — Specification [Withdrawn: replaced with ISO 424] ISO 3943:1993 Photography — Processing chemicals — Specifications for anhydrous sodium acetate ISO 3944:1992 Fertilizers — Determination of bulk density (loose) ISO 3945:1985 Mechanical vibration of large rotating machines with speed range from 10 to 200 r/s — Measurement and evaluation of vibration severity in situ [Withdrawn: replaced with ISO 10816-1] ISO 3946:1982 Starches and derived products — Determination of total phosphorus content — Spectrophotometric method ISO 3947:1977 Starches, native or modified — Determination of total fat content ISO 3948:1977 Shipbuilding — Inland vessels — Compressed-air systems — Pressure ranges [Withdrawn without replacement] ISO 3949:2020 Plastics hoses and hose assemblies — Textile-reinforced types for hydraulic applications — Specification ISO 3950:2016 Dentistry – Designation system for teeth and areas of the oral cavity ISO 3951 Sampling procedures for inspection by variables ISO 3951-1:2022 Part 1: Specification for single sampling plans indexed by acceptance quality limit (AQL) for lot-by-lot inspection for a single quality characteristic and a single AQL ISO 3951-2:2013 Part 2: General specification for single sampling plans indexed by acceptance quality limit (AQL) for lot-by-lot inspection of independent quality characteristics ISO 3951-3:2007 Part 3: Double sampling schemes indexed by acceptance quality limit (AQL) for lot-by-lot inspection ISO 3951-4:2011 Part 4: Procedures for assessment of declared quality levels ISO 3951-5:2006 Part 5: Sequential sampling plans indexed by acceptance quality limit (AQL) for inspection by variables (known standard deviation) ISO 3952 Kinematic diagrams – Graphical symbols ISO 3952-1:1981 (Motion of links of mechanisms; Kinematic pairs; Links and connections of their components; Linkage of bars and their links) ISO 3952-2:1981 (Friction and gear mechanisms; Cam mechanisms) ISO 3952-3:1979 (Maltese and ratchet mechanisms; Couplings and brakes) ISO 3952-4:1984 (Miscellaneous mechanisms and their components) ISO 3953:2011 Metallic powders — Determination of tap density ISO 3954:2007 Powders for powder metallurgical purposes — Sampling ISO 3955:1977 Sintered metal materials, excluding hardmetals — Sampling [Withdrawn without replacement] ISO/TR 3956:1975 Principles of structural fire-engineering design with special regard to the connection between real fire exposure and the heating conditions of the standard fire-resistance test (ISO 834) ISO 3957:2025 Reaction to fire tests — Façades — Measurement of heat and smoke generation in severe exterior fire scenarios [original draft Graphic symbols — Index, survey, and compilation of the single sheets became ISO 7000] ISO 3958:1996 Passenger cars — Driver hand-control reach ISO 3959:1977 Green bananas — Ripening conditions ISO 3960:2017 Animal and vegetable fats and oils — Determination of peroxide value — Iodometric (visual) endpoint determination ISO 3961:2018 Animal and vegetable fats and oils — Determination of iodine value ISO 3962:1977 Materials and equipment for petroleum and natural gas industries — Tool joints for steel drill pipe for oil or natural gas wells [Withdrawn without replacement] ISO 3963:1977 Fertilizers — Sampling from a conveyor by stopping the belt ISO 3964:2016 Dentistry — Coupling dimensions for handpiece connectors ISO 3965:1990 Agricultural wheeled tractors — Maximum speeds — Method of determination ISO 3966:2020 Measurement of fluid flow in closed conduits – Velocity area method using Pitot static tubes ISO 3967 Petroleum products – Determination of density and relative density – Bingham pyknometer method [Rejected draft] ISO 3968:2017 Hydraulic fluid power — Filters — Evaluation of differential pressure versus flow ISO 3969:1979 Shipbuilding — Inland vessels — Operational documentation [Withdrawn without replacement] ISO 3970:1977 Modular units for machine tool construction — Integral way columns — Floor-mounted type ISO 3971:1977 Rice milling — Symbols and equivalent terms [Withdrawn without replacement] ISO 3972:2011 Sensory analysis — Methodology — Method of investigating sensitivity of taste ISO 3973:1996 Living animals for slaughter — Vocabulary — Bovines [Withdrawn without replacement] ISO 3974:1977 Definitions of living animals for slaughter — Ovines ISO 3975:1977 Definitions of living animals for slaughter — Horses [Withdrawn without replacement] ISO 3976:2006 Milk fat — Determination of peroxide value ISO 3977 Gas turbines – Procurement ISO 3978:1976 Aluminium and aluminium alloys — Determination of chromium — Spectrophotometric method using diphenylcarbazide, after extraction ISO 3979:1977 Aluminium and aluminium alloys — Determination of nickel — Spectrophotometric method using dimethylglyoxime [Withdrawn without replacement] ISO 3980:1977 Aluminium and aluminium alloys — Determination of copper — Atomic absorption spectrophotometric method ISO 3981:1977 Aluminium and aluminium alloys — Determination of nickel — Atomic absorption spectrophotometric method ISO 3982 Chemical analysis of aluminum and its alloys — Complexometric determination of magnesium [Rejected draft] ISO 3983:1977 Cereals and cereal products — Determination of alpha-amylase activity — Colorimetric method [Withdrawn without replacement] ISO 3984:2004 Road vehicles — Rear moving barrier impact test procedure [Withdrawn without replacement] ISO/TR 3985:2021 Biotechnology — Data publication — Preliminary considerations and concepts [Original draft with this number unknown] ISO 3986 Petroleum products — Lubricating wax — Determination of cone penetration [Rejected draft] ISO 3987:2010 Petroleum products — Determination of sulfated ash in lubricating oils and additives ISO 3988 Determination of Spontaneous ignition temperature [Rejected draft] ISO 3989 Measurement of airborne noise emitted by compressor units including prime movers [Rejected draft] ISO 3990:2023 Dentistry — Evaluation of antibacterial activity of dental restorative materials, luting cements, fissure sealants and orthodontic bonding or luting materials [original draft was Modular co-ordination — Sizes for co-ordinating lengths and widths of openings in the horizontal plane] ISO 3991:2025 Agricultural machinery — Robotic feed systems — Safety [original draft was Modular co-ordination — Sizes for co-ordinating heights of openings in the vertical plane] ISO 3992 Petroleum waxes — Determination of needle penetration [Rejected draft] ISO 3993:1984 Liquefied petroleum gas and light hydrocarbons — Determination of density or relative density — Pressure hydrometer method ISO 3994:2014 Plastics hoses — Helical-thermoplastic-reinforced thermoplastics hoses for suction and discharge of aqueous materials — Specification ISO 3995:1985 Metallic powders — Determination of green strength by transverse rupture of rectangular compacts ISO 3996:1995 Road vehicles — Brake hose assemblies for hydraulic braking systems used with non-petroleum-base brake fluid ISO 3997 Bitumen and bituminous binders – Determination of needle penetration [Rejected draft] ISO 3998:1977 Textiles — Determination of resistance to certain insect pests ISO 3999:2004 Radiation protection — Apparatus for industrial gamma radiography — Specifications for performance, design and tests
== External links == "Dr. A. Ajayaghosh". Awardee profile. Infosys Science Foundation. 2016. "Dr. A. Ajayaghosh". Infosys Science Foundation. 26 September 2013. p. YouTube video. "Dr. A. Ajayaghosh'' https://scholar.google.com/citations?user=bYdujAwAAAAJ&hl=en
The Chilean blob or Chilean monster (Spanish: Monstruo chileno) was a large globster (mass of organic tissue) found on Pinuno Beach in Los Muermos, Chile, in July 2003. It weighed 13 tonnes (14 tons) and measured 12 metres (39 ft) across. The Chilean blob made headlines around the world because biologists were initially unable to identify it and were speculating that it was the remains of some species of giant octopus previously unknown to science. The blob was the subject of a number of conspiracy theories. In June 2004, although no cells remained in the blob, fragments of the DNA found in the blob were found to match that of a sperm whale. The blob was a large mass of adipose tissue, the partial remains of a dead sperm whale. Scientists concluded that the whale had died several months prior and that its carcass had been eaten until only its tough collagen fibres remained.
The largest known T. rex skulls measure up to 1.52 m (5 ft 0 in) in length. Large fenestrae (openings) in the skull reduced weight, as in all carnivorous theropods. In other respects Tyrannosaurus's skull was significantly different from those of large non-tyrannosaurid theropods. It was extremely wide at the rear but had a narrow snout, allowing unusually good binocular vision. The skull bones were massive and the nasals and some other bones were fused, preventing movement between them; but many were pneumatized (contained a "honeycomb" of tiny air spaces) and thus lighter. These and other skull-strengthening features are part of the tyrannosaurid trend towards an increasingly powerful bite, which easily surpassed that of all non-tyrannosaurids. The tip of the upper jaw was U-shaped (most non-tyrannosauroid carnivores had V-shaped upper jaws), which increased the amount of tissue and bone a tyrannosaur could rip out with one bite, although it also increased the stresses on the front teeth. The teeth of T. rex displayed marked heterodonty (differences in shape). The premaxillary teeth, four per side at the front of the upper jaw, were closely packed, D-shaped in cross-section, had reinforcing ridges on the rear surface, were incisiform (their tips were chisel-like blades) and curved backwards. The D-shaped cross-section, reinforcing ridges and backwards curve reduced the risk that the teeth would snap when Tyrannosaurus bit and pulled. The remaining teeth were robust, like "lethal bananas" rather than daggers, more widely spaced and also had reinforcing ridges.
In molecular biology, fibrous proteins or scleroproteins are one of the three main classifications of protein structure (alongside globular and membrane proteins). Fibrous proteins are made up of elongated or fibrous polypeptide chains which form filamentous and sheet-like structures. This kind of protein can be distinguished from globular protein by its low solubility in water. In contrast, globular proteins are spherical and generally soluble in water, performing dynamic functions like enzymatic activity or transport. Such proteins serve protective and structural roles by forming connective tissue, tendons, bone matrices, and muscle fiber. Fibrous proteins consist of many families including keratin, collagen, elastin, fibrin or spidroin. Collagen is the most abundant of these proteins which exists in vertebrate connective tissue including tendon, cartilage, and bone.
Sources: en.wikipedia.org
Common methods include enzymatic recycling assays, liquid chromatography, and mass spectrometry. Many protocols separate reduced glutathione from its oxidized disulfide form before detection.
The ratio compares reduced glutathione with its oxidized dimer. It is used as an indicator of redox status, although the value depends strongly on sample handling and analytical method.
Glutathione can oxidize quickly after a sample is collected. Acidification, cooling, and chelators are often used to reduce artifactual changes before analysis.
Chromatographic methods can separate the two forms before detection. Enzymatic assays often measure total glutathione first and then use a separate procedure to estimate the oxidized fraction. The difference between total and oxidized amounts provides an indirect estimate of the reduced form.