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;
Nitrogen Cycle. The nitrogen cycle is dominated by the N2 gas in the atmosphere. Nitrous oxide, N2O is the second common form. N20 (the gas commonly known as laughing gas) is a greenhouse gas. Seventy-nine percent of the atmosphere is nitrogen in the form of N2 gas. Because N2 has low reactivity, it offsets the high reactivity of oxygen, O2, the other major constituents of the atmosphere. For example when we light a match, the nitrogen does not burn with the oxygen.