THE FIELD OF TRANSPORT PHYSIOLOGY was fundamentally changed by the discovery of transport proteins that are specific for small neutral molecules such as urea, water, ammonia, and CO2. The identification of first urea transporters (12), then aquaporins or water channels (1), and most recently ammonia transporters (8) (that may also facilitate the movement of CO2), challenged the long-held view t...

The cyclotron-produced radionuclide, 13N, was used to label ammonia and to study its metabolism in a group of 5 normal subjects and 17 patients with liver disease, including 5 with portacaval shunts and 11 with encephalopathy. Arterial ammonia levels were 52-264 micron. The rate of ammonia clearance from the vascular compartment (metabolism) was a linear function of its arterial concentration: ...

In this study performance characteristics of ammonia engines using direct injection strategies are investigated. Ammonia is a carbon-free fuel, and thus its combustion does not produce carbon dioxide, a critical greenhouse gas. Ammonia can be produced by using renewable energy sources (e.g., wind and solar) and used as an energy carrier. Recent research also has shown that the efficiency of sol...

Nitrogen (N) appears to be a limiting dietary resource for elasmobranchs, required not only for protein growth but also for urea-based osmoregulation. Building on recent evidence that the toxicant ammonia can be taken up actively at the gills of the shark and made into the valuable osmolyte urea, we demonstrate that the uptake exhibits classic Michaelis-Menten saturation kinetics with an affini...

this study was conducted to determine in vitro crude protein degradation (ivdp) parameters and effective crude protein degradability (epd) of various feeds using the modified in vitro gas production (gp) technique. feed samples were alfalfa hay, soybean meal, soybean, rapeseed meal, sunflower meal and fish meal. rumen fluid was collected before the morning feeding from four rumen fistulated lam...

conclusions the results indicated that the model, compared with other models, was user-friendly and the desired results were obtained by a minimal data. materials and methods the current paper developed a process model. first, a sketch of nitrate and ammonia storage, their specifications and parameters were set out and created on a page, and then, mathematical relations of each process were set...

Excessive amounts of ammonia are known to inhibit exoelectrogenic activities in microbial fuel cells (MFCs). However, the threshold ammonia concentration that triggers toxic effects is not consistent among literature papers, indicating that ammonia inhibition can be affected by other operational factors. Here, we examined the effect of substrate concentration and feed frequency on the capacity ...

The storage and handling of animal wastes is one of the main sources of ammonia gas emissions. Ammonia gas has a distinct, unpleasant odor and can become detrimental to the health of humans and animals at high concentrations. Ammonia emissions are of particular concern in manure drying systems, where large losses of nitrogen, in the form of ammonia can cause air quality concerns. The aim of thi...

Capturing ammonia from anaerobically digested manure could simultaneously decrease the adverse effects of ammonia inhibition on biogas production, reduce reactive nitrogen (N) loss to the environment, and produce mineral N fertilizer as a by-product. In this study, gas permeable membranes (GPM) were used to capture ammonia from dairy manure and digestate by the diffusion of gaseous ammonia acro...

Ammonia losses during swine wastewater treatment were examined using single- and two-chambered microbial fuel cells (MFCs). Ammonia removal was 60% over 5 days for a single-chamber MFC with the cathode exposed to air (air-cathode), versus 69% over 13 days from the anode chamber in a two-chamber MFC with a ferricyanide catholyte. In both types of systems, ammonia losses were accelerated with ele...