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  2. Bosch-Meiser process - Wikipedia

    en.wikipedia.org/wiki/Bosch-Meiser_process

    Urea plant using ammonium carbamate briquettes, Fixed Nitrogen Research Laboratory, ca. 1930 Carl Bosch, 1927. The Bosch–Meiser process is an industrial process, which was patented in 1922 [1] and named after its discoverers, the German chemists Carl Bosch and Wilhelm Meiser [2] for the large-scale manufacturing of urea, a valuable nitrogenous chemical.

  3. Urea cycle - Wikipedia

    en.wikipedia.org/wiki/Urea_cycle

    3, to the relatively nontoxic excretion product urea. [6] This occurs at the cost of four "high-energy" phosphate bonds (3 ATP hydrolyzed to 2 ADP and one AMP). The conversion from ammonia to urea happens in five main steps. The first is needed for ammonia to enter the cycle and the following four are all a part of the cycle itself.

  4. Renal physiology - Wikipedia

    en.wikipedia.org/wiki/Renal_physiology

    Urea is usually excreted as a waste product from the kidneys. However, when plasma blood volume is low and ADH is released the aquaporins that are opened are also permeable to urea. This allows urea to leave the collecting duct into the medulla, creating a hyperosmotic solution that "attracts" water.

  5. Berthelot's reagent - Wikipedia

    en.wikipedia.org/wiki/Berthelot's_reagent

    Phenol in the Berthelot reagent can be replaced by a variety of phenolic reagents, the most common being sodium salicylate, which is significantly less toxic. [1] This has been used for blood urea nitrogen (BUN) determinations and commonly is used to determine water and soil total and ammonia-N. Replacement of phenol by 2-phenylphenol reduces interferences by a variety of soil and water ...

  6. Purine nucleotide cycle - Wikipedia

    en.wikipedia.org/wiki/Purine_nucleotide_cycle

    NH 3 + H + ⇌ NH + 4. Ammonia (NH 3) diffuses into the blood, circulating to the liver to be neutralized by the urea cycle. (N.b. urea is not the same as uric acid, though both are end products of the purine nucleotide cycle, from ammonia and nucleotides

  7. Urea - Wikipedia

    en.wikipedia.org/wiki/Urea

    The structure of the molecule of urea is O=C(−NH 2) 2.The urea molecule is planar when in a solid crystal because of sp 2 hybridization of the N orbitals. [8] [9] It is non-planar with C 2 symmetry when in the gas phase [10] or in aqueous solution, [9] with C–N–H and H–N–H bond angles that are intermediate between the trigonal planar angle of 120° and the tetrahedral angle of 109.5°.

  8. Selective catalytic reduction - Wikipedia

    en.wikipedia.org/wiki/Selective_catalytic_reduction

    Selective catalytic reduction (SCR) means converting nitrogen oxides, also referred to as NO x with the aid of a catalyst into diatomic nitrogen (N 2), and water (H 2 O). A reductant, typically anhydrous ammonia (NH 3), aqueous ammonia (NH 4 OH), or a urea (CO(NH 2) 2) solution, is added to a stream of flue or exhaust gas and is reacted onto a ...

  9. Azotemia - Wikipedia

    en.wikipedia.org/wiki/Azotemia

    For historical reasons, the lab test measuring urea is known as "blood urea nitrogen" (BUN) in the US. The BUN:Cr ratio is a useful measure in determining the type of azotemia and will be discussed in each section below. A normal BUN:Cr is equal to 15. [3]