Both photogenerated carrier and photothermal effect enhanced electrochemical urea-assisted hydrogen generation on a Ni-NiO/Nickel Foam catalyst.

Feeding cattle diets high in degradable crude protein (CP) or in excess of requirements can reduce fertility and lower uterine pH. Objectives were to determine direct effects of urea and acidic pH during oocyte maturation and embryonic development. For experiment 1, oocytes were matured in medium containing 0, 5, 7.5, or 10 mM urea (0, 14, 21, or 28 mg/dl urea nitrogen, respectively). Cleavage ...

We show that diffusion of single urease enzyme molecules increases in the presence of urea in a concentration-dependent manner and calculate the force responsible for this increase. Urease diffusion measured using fluorescence correlation spectroscopy increased by 16-28% over buffer controls at urea concentrations ranging from 0.001 to 1 M. This increase was significantly attenuated when urease...

It has been observed experimentally that early distal tubular urea flow exceeds urea delivery by the proximal convoluted tubule to the pars recta and loop of Henle. Moreover, the fractional excretion of urea in the urine may exceed values compatible with the reabsorption known to occur in the proximal convoluted tubule in the cortex. A likely explanation for these observations is that urea may ...

1. Stable urea isotopes can be used to study urea kinetics in humans. The use of stable urea isotopes for studying urea kinetic parameters in humans on a large scale is hampered by the high costs of the labelled material. We devised a urea dilution for measurement of the distribution volume, production rate and clearance of urea in healthy subjects and renal failure patients using the inexpensi...

The objective of this study was to determine whether the pulsatile facilitated diffusion transport mechanism (tUT) found in the gills of the gulf toadfish (Opsanus beta) and the active secretion transporter thought to be present in its kidney could be saturated when faced with elevated plasma urea concentrations. Toadfish were infused with four consecutive exogenous urea loads at a rate of 0, 1...

A new method of estimating Kt/V has been proposed. This was a required update to accommodate frequencies of dialysis other than thrice weekly [1].The original approximate method for calculating Kt/V from preand post-dialysis urea concentrations was developed using linear regression on a data set of measurements taken from patients undergoing thrice-weekly dialysis. The method assumes that the i...

The variation of k10bs with [alkali] is linear. at [OH-]=5.0 to 1.5 mol dm-3, thereafter a sharp increase in the reaction rate is observed for first step hydrolysis of urea. The second step rate constant (k2obS)is found to be independent of [alkali].Hydrolysis of urea in alkaline medium follows an eleminationaddition mechanism. The reaction does not proceed through the formation and decompositi...

The views that catabolism of protein leads to net production of acid and that urinary excretion of ammonium ion represents an equimolar excretion of proton are not compatible with basic chemical relationships (Atkinson, D. E., and Camien, M, N. (1982) Curr. Top. Cell. Regul. 21, 261-302). Metabolism of protein produces significant amounts of base (bicarbonate), which is disposed of in the synth...

1. The rate of transfer of plasma urea-nitrogen to rumen ammonia was measured by infusion of 15NH4Cl and [15N]urea into sheep given brome grass (Bromus inermis) or lucerne (Medicago sativa) pellets. Urea was infused into the rumen or abomasum of two sheep given brome grass in order to increase the concentration of rumen ammonia. 2. From 6.2 to 9.8 g/d of plasma urea-N were transferred to the ru...