A missing link in the nitrogen cycle has recently been found: bacteria capable of oxidizing ammonium to nitrogen gas (N2). This new source of N2 has now been detected in both the water column and the sediments in marine environments. This discovery is important because it necessitates re-evaluation of (1) major fluxes in the global nitrogen budget and (2) regulation of the processes leading to ...

We report here on the production of nitrogen doped carbon using the hydrothermal carbonization process of nitrogen containing carbohydrates under mild carbonization temperatures. The resulting materials contain significant amounts of nitrogen in their composition and display a high degree of aromatisation. The nitrogen contents are also maintained after further calcination at higher temperature...

Due to an increasing demand of leaf vegetables, and hence their economic importance in the tropics, it is very common that excessive fertilizer N rates are applied to vegetable gardens and fields to attain high yield. This calls for more information on their nutrient requirements. In this study, we designed experiments to explore the effect of organic N levels on the yield and agronomic N use e...

This instrumental method for total urinary nitrogen (TUN) is based on the principle of gas-phase chemiluminescence. Results correlate well with measurements of TUN by the Kjeldahl method, which has long provided the means to calculate nitrogen balances for nutritional management. In recent years, because of speed and convenience of measurement, determination of urinary urea nitrogen (UUN) has b...

The nitrogen content of a large Walker car cinoma p256exceeds the amount of nitrogen stored by its host during the period of tumor growth (14). Therefore, part of the nitrogen contained in a tu mor must have been derived from the rat's body. Some tissues should then show a decrease in nitro gen content that may be detected by comparing the nitrogen content of the same tissues from tumor-bearing...

Nitrogen-doped graphene materials with abundant pyridinic and quaternary nitrogen species were selectively synthesized by thermal surface polymerization of nitrogen-containing aromatic molecules. Catalytic studies revealed that the oxygen reduction by nitrogen-doped graphene, containing pyridinic and quaternary nitrogen species, proceeds via a four- and two-electron reduction pathway, respectiv...

Nitrogen is a dominant regulator of vegetation dynamics, net primary production, and terrestrial carbon cycles; however, most ecosystem models use a rather simplistic relationship between leaf nitrogen content and photosynthetic capacity. Such an approach does not consider how patterns of nitrogen allocation may change with differences in light intensity, growing-season temperature and CO(2) co...

Four nutrient enrichment bioassay experiments were conducted in Sycamore Creek, Arizona, during summer and autumn 1983. In two experiments, nitrogen and phosphorus were added alone and in combination while in the other experiments nitrogen was added singly. In experiments involving enrichment of both nutrient-diffusing substrates (clay flowerpots) and streamwater overlying tileigravel artificia...