Sea urchin sperm motility is activated by a Na+-dependent increase of internal pH. A flagellar preparation was used in the present study to investigate this ionic mechanism. Using 22Na and a pH electrode, the stoichiometry of Na+ uptake to H+ release in the isolated flagella was found to be 1.09 +/- 0.11. Reversing the Na+ gradient induced reacidification of the intraflagellar pH as measured by...

-Ion-exchange experiments in expanding clay minerals conducted over a wide range of surface ionic compositions and ionic strength produce variable mass-action selectivity coefficients. When the exchanging ions are of unequal charge, tactoid structure appears to influence selectivity, although configurational entropy of adsorbed ions may also generate variable selectivity. The degree of deviatio...

The sorption ability of fast-coprecipitated and hydrothermally-treated Mg/Al layered double hydroxide nanoparticles (FCHT-LDH) for various oxyhalides and oxyanions was evaluated. Interactions of oxyhalide such as monovalent bromate or oxyanions such as divalent chromate and divalent vanadate with FCHT-LDH were investigated using a combination of macroscopic (batch sorption/desorption studies an...

the electronic structure, energy band structure and electronic density of 2 sno ceramic in cubicphase have been investigated using first principle full potential-linearized augmented plane wave (fp-lapw)method within density functional theory (dft). local density approximation (lda) and the generalizedgradient approximation (gga), which are based on exchange- correlation energy optimization wer...

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New bionanocomposite proton exchange membranes were prepared from sulfonated polybenzimidazole (s-PBI) and various amounts of sulfonated ZnO/cellulose nanohybrids (ZnO/cellulose-SO3H). The use of ZnO/cellulose-SO3H compensates for the decrease in ion exchange capacity of membranes observed when non-sulfonated nano-fillers are utilized. The strong –SO3H/–SO<su...

Na+/Ca2+exchange is the primary mechanism mediating Ca2+ efflux from cardiac myocytes during diastole and, thus, can prominently influence contractile force. In addition to transporting Na+and Ca2+, the exchanger is also regulated by these ions. Although structure-function studies have identified protein regions of the exchanger subserving these regulatory processes, their physiological importa...

The potential of cationic polyelectrolytes to precipitate host cell and process related impurities was investigated, to replace one or more chromatography steps in monoclonal antibody purification. The impact of antibody isoelectric point, solution properties (pH and ionic strength), and polyelectrolyte properties (structure, molecular weight and pK(a)) on the degree of precipitation was studie...