|
Dichlorophenolindophenol
2,6-Dichlorophenolindophenol (DCPIP, DCIP or DPIP) is a chemical compound used as a redox dye. When oxidized, DCPIP is blue with a maximal absorption at 600 nm; when reduced, DCPIP is colorless. DCPIP can be used to measure the rate of photosynthesis. It is part of the Hill reagents family. When exposed to light in a photosynthetic system, the dye is decolorised by chemical reduction. DCPIP has a higher affinity for electrons than ferredoxin and the photosynthetic electron transport chain can reduce DCPIP as a substitute for NADP+, that is normally the final electron carrier in photosynthesis. As DCPIP is reduced and becomes colorless, the resultant increase in light transmittance can be measured using a spectrophotometer. DCPIP can also be used as an indicator for vitamin C. If vitamin C, which is a good reducing agent, is present, the blue dye, which turns pink in acid conditions, is reduced to a colorless compound by ascorbic acid. This reaction is a redox reac ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Titration
Titration (also known as titrimetry and volumetric analysis) is a common laboratory method of quantitative chemical analysis to determine the concentration of an identified analyte (a substance to be analyzed). A reagent, termed the ''titrant'' or ''titrator'', is prepared as a standard solution of known concentration and volume. The titrant reacts with a solution of ''analyte'' (which may also be termed the ''titrand'') to determine the analyte's concentration. The volume of titrant that reacted with the analyte is termed the ''titration volume''. History and etymology The word "titration" descends from the French word ''titrer'' (1543), meaning the proportion of gold or silver in coins or in works of gold or silver; i.e., a measure of fineness or purity. ''Tiltre'' became ''titre'', which thus came to mean the "fineness of alloyed gold", and then the "concentration of a substance in a given sample". In 1828, the French chemist Joseph Louis Gay-Lussac first used ''titre'' as ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Indophenol
Indophenol is an organic compound with the formula OC6H4NC6H4OH. It is deep blue dye that is the product of the Berthelot's reaction, a common test for ammonia. The indophenol group, with various substituents in place of O''H'' and various ring substitutions, is found in many dyes used in hair coloring and textiles. Indophenol is used in hair dyes, lubricants, redox materials, liquid crystal displays, fuel cells and chemical-mechanical polishing. It is an environmental pollutant and is toxic to fish. Berthelot test In the Berthelot test (1859), a sample suspected of having containing ammonia is treated with sodium hypochlorite and phenol. The formation of indophenol is used to determine ammonia and paracetamol by spectrophotometry. Other phenols can be used. Dichlorophenol-indophenol (DCPIP), a form of indophenol, is often used to determine the presence of vitamin C (ascorbic acid). Related compounds Indophenol blue is a different compound with systematic name A systematic n ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Indophenol Dyes
Indophenol is an organic compound with the formula OC6H4NC6H4OH. It is deep blue dye that is the product of the Berthelot's reaction, a common test for ammonia. The indophenol group, with various substituents in place of O''H'' and various ring substitutions, is found in many dyes used in hair coloring and textiles. Indophenol is used in hair dyes, lubricants, redox materials, liquid crystal displays, fuel cells and chemical-mechanical polishing. It is an environmental pollutant and is toxic to fish. Berthelot test In the Berthelot test (1859), a sample suspected of having containing ammonia is treated with sodium hypochlorite and phenol. The formation of indophenol is used to determine ammonia and paracetamol by spectrophotometry. Other phenols can be used. Dichlorophenol-indophenol (DCPIP), a form of indophenol, is often used to determine the presence of vitamin C ( ascorbic acid). Related compounds Indophenol blue is a different compound with systematic name A systema ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chemical Compound
A chemical compound is a chemical substance composed of many identical molecules (or molecular entities) containing atoms from more than one chemical element held together by chemical bonds. A molecule consisting of atoms of only one element is therefore not a compound. A compound can be transformed into a different substance by a chemical reaction, which may involve interactions with other substances. In this process, bonds between atoms may be broken and/or new bonds formed. There are four major types of compounds, distinguished by how the constituent atoms are bonded together. Molecular compounds are held together by covalent bonds; ionic compounds are held together by ionic bonds; intermetallic compounds are held together by metallic bonds; coordination complexes are held together by coordinate covalent bonds. Non-stoichiometric compounds form a disputed marginal case. A chemical formula specifies the number of atoms of each element in a compound molecule, using the s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dehydroascorbic Acid
Dehydroascorbic acid (DHA) is an oxidized form of ascorbic acid (vitamin C). It is actively imported into the endoplasmic reticulum of cells via glucose transporters. It is trapped therein by reduction back to ascorbate by glutathione and other thiols. The (free) chemical radical semidehydroascorbic acid (SDA) also belongs to the group of oxidized ascorbic acids. Structure and physiology Top: ascorbic acid(reduced form of vitamin C)Bottom: dehydroascorbic acid( nominal oxidized form of vitamin C) Although a sodium-dependent transporter for vitamin C exists, it is present mainly in specialized cells, whereas the glucose transporters, the most notable being GLUT1, transport Vitamin C (in its oxidized form, DHA) in most cells, where recycling back to ascorbate generates the necessary enzyme cofactor and intracellular antioxidant, (see Transport to mitochondria). The structure shown here for DHA is the commonly shown textbook structure. This 1,2,3-tricarbonyl is too electrop ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wurster's Blue
Wurster's blue is the trivial name given to the chemical ''N'',''N'',''N''′,''N''′-tetramethyl-''p''-phenylenediamine, also known as TMPD. It is an easily oxidised phenylenediamine, which loses two electrons in one-electron oxidation steps; the radical cation is a characteristic blue-violet colour, which gives the compound part of its name. The remaining part of its name comes from its discoverer, the German chemist Casimir Wurster (7 August 1854 – 29 November 1913). The hydrochloride salt finds use as a redox indicator in the oxidase test and is also used in electron transport chain analysis as it is capable of donating electrons to cytochrome c. The term "Wurster's blue" is often reserved for the radical cation, the colorless diamine being called tetramethylphenylenediamine (TMPD). The midpoint potential for titration of the first electron is given as 0.276 V vs NHE, and this transition is useful in potentiometric titrations as both a redox mediator and indicator. Th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Methylene Blue
Methylthioninium chloride, commonly called methylene blue, is a salt used as a dye and as a medication. Methylene blue is a thiazine dye. As a medication, it is mainly used to treat methemoglobinemia by converting the ferric iron in hemoglobin to ferrous iron. Specifically, it is used to treat methemoglobin levels that are greater than 30% or in which there are symptoms despite oxygen therapy. It has previously been used for treating cyanide poisoning and urinary tract infections, but this use is no longer recommended. Methylene blue is typically given by injection into a vein. Common side effects include headache, vomiting, confusion, shortness of breath, and high blood pressure. Other side effects include serotonin syndrome, red blood cell breakdown, and allergic reactions. Use often turns the urine, sweat, and stool blue to green in color. While use during pregnancy may harm the baby, not using it in methemoglobinemia is likely more dangerous. Methylene blue was first pr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Metachromasy
Metachromasia (var. metachromasy) is a characteristical change in the color of staining carried out in biological tissues, exhibited by certain dyes when they bind to particular substances present in these tissues, called chromotropes. For example, toluidine blue becomes dark blue (with a colour range from blue-red dependent on glycosaminoglycan content) when bound to cartilage. Other widely used metachromatic stains are the haematological Giemsa and May-Grunwald stains that also contain thiazine dyes. The white cell nucleus stains purple, basophil granules intense magenta, whilst the cytoplasms (of mononuclear cells) stains blue. The absence of color change in staining is named orthochromasia. The underlying mechanism for metachromasia requires the presence of polyanions within the tissue. When these tissues are stained with a concentrated basic dye solution, such as toluidine blue, the bound dye molecules are close enough to form dimeric and polymeric aggregates. The light abso ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oxidative Stress
Oxidative stress reflects an imbalance between the systemic manifestation of reactive oxygen species and a biological system's ability to readily Detoxification, detoxify the reactive intermediates or to repair the resulting damage. Disturbances in the normal redox state of cells can cause toxic effects through the production of peroxides and free radicals that damage all components of the cell, including proteins, lipids, and DNA. Oxidative stress from Cellular respiration, oxidative metabolism causes base damage, as well as DNA damage (naturally occurring), strand breaks in DNA. Base damage is mostly indirect and caused by the reactive oxygen species generated, e.g., O2− (superoxide radical), OH (hydroxyl radical) and H2O2 (hydrogen peroxide). Further, some reactive oxidative species act as cellular messengers in redox signaling. Thus, oxidative stress can cause disruptions in normal mechanisms of cellular signaling. In humans, oxidative stress is thought to be involved in the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Glutathione
Glutathione (GSH, ) is an antioxidant in plants, animals, fungi, and some bacteria and archaea. Glutathione is capable of preventing damage to important cellular components caused by sources such as reactive oxygen species, free radicals, peroxides, lipid peroxides, and heavy metals. It is a tripeptide with a gamma peptide linkage between the carboxyl group of the glutamate side chain and cysteine. The carboxyl group of the cysteine residue is attached by normal peptide linkage to glycine. Biosynthesis and occurrence Glutathione biosynthesis involves two adenosine triphosphate-dependent steps: *First, γ-glutamylcysteine is synthesized from L- glutamate and cysteine. This conversion requires the enzyme glutamate–cysteine ligase (GCL, glutamate cysteine synthase). This reaction is the rate-limiting step in glutathione synthesis. *Second, glycine is added to the C-terminal of γ-glutamylcysteine. This condensation is catalyzed by glutathione synthetase. While all animal ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Melanoma
Melanoma, also redundantly known as malignant melanoma, is a type of skin cancer that develops from the pigment-producing cells known as melanocytes. Melanomas typically occur in the skin, but may rarely occur in the mouth, intestines, or eye (uveal melanoma). In women, they most commonly occur on the legs, while in men, they most commonly occur on the back. About 25% of melanomas develop from moles. Changes in a mole that can indicate melanoma include an increase in size, irregular edges, change in color, itchiness, or skin breakdown. The primary cause of melanoma is ultraviolet light (UV) exposure in those with low levels of the skin pigment melanin. The UV light may be from the sun or other sources, such as tanning devices. Those with many moles, a history of affected family members, and poor immune function are at greater risk. A number of rare genetic conditions, such as xeroderma pigmentosum, also increase the risk. Diagnosis is by biopsy and analysis of any skin lesion ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pro-oxidant
Pro-oxidants are chemicals that induce oxidative stress, either by generating reactive oxygen species or by inhibiting antioxidant systems. The oxidative stress produced by these chemicals can damage cells and tissues, for example an overdose of the analgesic paracetamol (acetaminophen) can fatally damage the liver, partly through its production of reactive oxygen species. Some substances can serve as either antioxidants or pro-oxidants, depending on conditions. Some of the conditions that are important include the concentration of the chemical and if oxygen or transition metals are present. While thermodynamically very favored, reduction of molecular oxygen or peroxide to superoxide or hydroxyl radical respectively is spin forbidden. This greatly reduces the rates of these reactions, thus allowing aerobic life to exist. As a result, the reduction of oxygen typically involves either the initial formation of singlet oxygen, or spin-orbit coupling through a reduction of a transitio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
