A malignant fibrous histiocytoma with a predominance of myxoid areas that resemble primitive mesenchymal tissue. [myxo- + L. fibra, fiber, + G. sarx, flesh, + -Åma, tumor]. /myxoÂ·fiÂ·broÂ·sarÂ·coÂ·ma/ (-fiâ³bro-sahr-koÂ´mah) older term for the myxoid subtype of malignant fibrous histiocytoma.
1 Ammonium ion (NH4+), the most reduced natural specie of nitrogen, and the most biologically available in an oxygen-less environment;  Nitrate ion (NO3-), the most oxidized form of nitrogen and mostly usable in an aerobic environment;
The oxidation of most organic compounds by dichromate is 95 to 100 per-. cent of the theoretical value. However, ammonia, urea, benzene, toluene, and pyridine are among the compounds that are not oxidized by dichromate. Since urine contains large amounts of urea, ammonia and amines, its COD.