Absorption of NH(4)(+) by the medullary thick ascending limb (MTAL) is a key event in the renal handling of NH(4)(+), leading to accumulation of NH(4)(+)/NH(3) in the renal medulla, which favors NH(4)(+) secretion in medullary collecting ducts and excretion in urine. The Na(+)-K(+)(NH(4)(+))-2Cl(-) cotransporter (BSC1/NKCC2) ensures approximately 50-65% of MTAL active luminal NH(4)(+) uptake un...

This paper reports the first characterization of the (NH(3))(n)NH+ cluster series produced by a 252Cf fission fragments (FF) impact onto a NH(3) ice target. The (NH(3))(n=1-6)NH+ members of this series have been analyzed theoretically and experimentally. Their ion desorption yields show an exponential dependence of the cluster population on its mass, presenting a relative higher abundance at n ...

• We report the first use of tracer 13 NH 4 + ( 13 N-ammonium) efflux and retention data to analyse subcellular fluxes and compartmentation of NH 4 + in the leaves of a higher plant (wheat, Triticum aestivum ). • Leaf segments, 1–2 mm, were obtained from 8-d-old seedlings. The viability of the segments, and stability of NH 4 + acquisition over time, were confirmed using oxygen-exchange and NH 4...

Trypsin activates proteinase-activated receptor-2 (PAR(2)) by a mechanism that involves the release of a tethered receptor-activating sequence. We have identified two peptides, FSLLRY-NH(2) (FSY-NH(2)) and LSIGRL-NH(2) (LS-NH(2)) that block the ability of trypsin to activate PAR(2) either in PAR(2)-expressing Kirsten virus-transformed kidney (KNRK) cell lines or in a rat aorta ring preparation....

this research has been carried out to study and find a rather general description for a lone pairorbital in molecules. since the orbital parameters must be manageable in advance, and correctgeometry of the molecule (bond lengths) is depend on the appropriate lone pair description; thefsgo method including optimization has been used to obtain orbital parameters and energy. theproposed models for...

Possessing high H(2) capacities and interesting dehydrogenation behavior, metal amidoborane ammoniates were prepared by reacting Ca(NH(2) )(2) , MgNH, and LiNH(2) with ammonia borane to form Ca(NH(2) BH(3) )(2) ⋅2 NH(3) , Mg(NH(2) BH(3) )(2) ⋅NH(3) , and Li(NH(2) BH(3) )(2) ⋅NH(3) (LiAB⋅NH(3) ). Insight into the mechanisms of amidoborane ammoniate formation and dehydrogenation was obtained b...

In order to investigate the deuteration effect on the vibrational dynamics of the NH and/or ND stretch excited levels of the 7-azaindole (7-AI) normal dimer and its tautomeric dimer, we have carried out infrared spectroscopy of three isotopic species for each dimers; undeuterated one (NH-NH) and one or two hydrogen atom(s) of the NH groups is deuterated ones (NH-ND and ND-ND, respectively). It ...

The synthesis and isolation of the sodium salt of cyclo-tri-μ-imidotetraphosphate, i.e. Na4cP4O9(NH)3·H2O, were achieved by the hydrolysis of Na4cP4O8(NH)4·2H2O under very weak acidic conditions, i.e. using 0.2 mol L(-1) propionic acid and the pH-controlled recrystallization procedure. The purity of Na4cP4O9(NH)3·H2O was improved from 2% to 95% by the pH-controlled recrystallization only two ti...

There appears to be a flux of ammonium (NH(4)(+)/NH(3)) from neurons to glial cells in most nervous tissues. In bee retinal glial cells, NH(4)(+)/NH(3) uptake is at least partly by chloride-dependant transport of the ionic form NH(4)(+). Transmembrane transport of NH(4)(+) has been described previously on transporters on which NH(4)(+) replaces K(+), or, more rarely, Na(+) or H(+), but no trans...

an extraction-spectrophotometric method for the determination of trace amounts of ammonium ion is described. ammonium ion is effectively extracted as a neutral ternary complex nh . db 18c6. calmagite at ph 3.0 into chloroform, followed by spectrophotometric determination at =48 5 nm. molar absorptivity of the ternary complex at this wavelength is 1.08 10 mol cm . beer's law is obeyed over ...