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  2. Phenazopyridine - Wikipedia

    en.wikipedia.org/wiki/Phenazopyridine

    Phenazopyridine is an azo dye. [17] [18] Other azo dyes, which were previously used in textiles, printing, and plastic manufacturing, have been implicated as carcinogens that can cause bladder cancer. [19] While phenazopyridine has never been shown to cause cancer in humans, evidence from animal models suggests that it is potentially ...

  3. Griess test - Wikipedia

    en.wikipedia.org/wiki/Griess_test

    When sulfanilamide is added, the nitrite ion reacts with it in the Griess diazotization reaction to form a diazonium salt, which then reacts with N-(1-naphthyl)ethylenediamine in an azo coupling reaction, forming a pink-red azo dye. Using a spectrophotometer, it is possible to quantitatively determine the nitrite concentration. The detection ...

  4. Nitrite test - Wikipedia

    en.wikipedia.org/wiki/Nitrite_test

    A nitrite test is a standard component of a urinary test strip. A positive test for nitrites in the urine is called nitrituria. This test is commonly used in diagnosing urinary tract infections (UTIs). A positive nitrite test indicates that the cause of the UTI is a Gram-negative organism, most commonly Escherichia coli. The reason for nitrites ...

  5. Tooth discoloration - Wikipedia

    en.wikipedia.org/wiki/Tooth_discoloration

    Teeth affected in this way are also usually more susceptible to further staining acquired throughout life. Amelogenesis imperfecta is a rare condition that affects the formation of enamel (amelogenesis). The enamel is fragile, the teeth appear yellow or brown, and surface stains build up more readily. [1]

  6. Azo compound - Wikipedia

    en.wikipedia.org/wiki/Azo_compound

    Azo compounds are organic compounds bearing the functional group diazenyl (R−N=N−R′, in which R and R′ can be either aryl or alkyl groups).. IUPAC defines azo compounds as: "Derivatives of diazene (diimide), HN=NH, wherein both hydrogens are substituted by hydrocarbyl groups, e.g. PhN=NPh azobenzene or diphenyldiazene.", where Ph stands for phenyl group. [1]

  7. Nitrifying bacteria - Wikipedia

    en.wikipedia.org/wiki/Nitrifying_bacteria

    Many species of nitrifying bacteria have complex internal membrane systems that are the location for key enzymes in nitrification: ammonia monooxygenase (which oxidizes ammonia to hydroxylamine), hydroxylamine oxidoreductase (which oxidizes hydroxylamine to nitric oxide - which is further oxidized to nitrite by a currently unidentified enzyme ...

  8. Dental plaque - Wikipedia

    en.wikipedia.org/wiki/Dental_plaque

    Supragingival biofilm is dental plaque that forms above the gums, and is the first kind of plaque to form after the brushing of the teeth. It commonly forms in between the teeth, in the pits and grooves of the teeth and along the gums. It is made up of mostly aerobic bacteria, meaning these bacteria need oxygen to survive.

  9. Azo violet - Wikipedia

    en.wikipedia.org/wiki/Azo_violet

    Azo violet can be synthesised by reacting 4-nitroaniline with nitrous acid (generated in situ with an acid and a nitrite salt) to produce a diazonium intermediate. This is then reacted with resorcinol, dissolved in a sodium hydroxide solution, via an azo coupling reaction. This is consistent with the generalized strategy for preparing azo dyes.