Amount Of Ni2 Research Articles

Nickel absorption from perfused rat jejunal and ileal segments.

The intestinal absorption of Ni2+ was studied in isolated perfused jejunal and ileal segments of rats, by a method which allows continuous sampling of the absorbates. The results showed that the Ni(2+)-absorption proceeds at a much higher rate in the jejunum than in the ileum. Several observations indicate that Ni2+ is absorbed actively in the jejunum. There are indications in the literature that Ni2+ at least partly may share the transport mechanism for iron across the intestinal mucosa and our results may reflect the participation of Ni2+ in this absorptive process. The transfer of Ni2+ across the ileal epithelium may occur by passive diffusion. Addition of Zn2+, Co2+, Cd2+ or Hg2+ to the jejunal perfusates affected the Ni(2+)-absorption to varying extents. Thus, Zn2+ had minor effects on the Ni(2+)-absorption. Co2+ decreased the Ni(2+)-concentration in the absorbates, possibly by interfering with Ni2+ in the iron transfer process. Addition of Cd2+ or Hg2+ to the perfusates resulted in decreased jejunal water absorption. Hg2+ also depressed the glucose absorption. These results show that Cd2+ and Hg2+ at low concentrations are toxic to the jejunal mucosal cells. Thus, these metals can inhibit the amount of Ni2+ transferred across the intestinal mucosa by decreasing the volume of the absorbate.

Studies on the Catalyst for the Production of N, N-Dimethyl (Long-chain Alkyl Amines)

N, N-dimethyl(long-chain alkylamines)are one of the most important fatty chemicals, far example, as the industrial intermediates which are derived to many commercial products such as the quarternary ammonium salts, amine oxide and so forth. These N, N-dimethyl (long-chain alkylamines)have been synthesized from the corresponding alcohols economically over many kinds of heterogeneous catalysts. But these catalysts are not satisfactory enough both in activity and selectivity.The mechanism of the amination of alcohols has been investigated for a long time, and required the dehydrogenation and hydrogenolysis abilities of the catalysts used in this reaction.We, in this work, planned to use copper as the catalyst for dehydrogenation and nickel as that far hydrogenolysis, and found Cu-Ni catalyst supported on SiO2/Al2O3 gave very high activity and selectivity in the amination of dodecyl alcohol. When the weight ratio of Cu/Ni was 4/1, it gave the maximum of activity and selectivity.The valence states of surface metals of the catalyst were analyzed by using ESCA. Copper was reduced to Cu0 or Cu+ in the hydrogen atmosphere at 200°C. Nickel was not reduced in the same atmosphere.When there was much amount of Ni2+ on the catalyst surface, the selectivity for the amination reaction was low, Ni2+ was seemed to accelerate the disproportionation of dimethylamine (DMA).

Effects of Ca2+ and other divalent cations on uptake of Ni2+ by excised barley roots

Excised roots of 7‐day‐old, dark‐grown barley (Hordeum vulgare L. cvs Gunilla and Møyar) were used to characterize effects of Ca2+ and other divalent cations on uptake of Ni2+ (63Ni2+). The uptake of Ni2+ in the roots (free space uptake and influx) and the Ni2+ remaining in the roots after desorption for 15 min in 1.0 mM EDTA (mainly in‐flux) were both independent of the Ca2+ concentration in the pretreatment solution up to about 0.1 mM and then increased to a maximum at 1 mM Ca2+. Without pretreatment, the higher the Ca2+ concentration in the uptake solution, the less Ni2+ was taken up. Ni2+ influx in the roots was reduced less by Ca2+ than was loose binding of Ni2+ in the free space of the roots (the amount of Ni2+ removed by the desorption procedure). The ratio between Ni2+ influx and Ni2+ uptake had a maximum around 1 mM Ca2+ and was higher the lower the external Ni2+ concentration. With Mg2+ in the uptake solution, Ni2+ influx was more reduced than loose binding of Ni2+, in contrast to the results with Ca2+. Both Ca2+ and Mg2+ were non‐competitive inhibitors of Ni2+ influx. Mn2+ did not influence Ni2+ influx, whereas Zn2+ and Cu2+ inhibited Ni2+ influx strongly and competitively and Co2+ weakly and competitively. The heavy metals Cd2+ and Pb2+ appeared to inhibit Ni2+ influx non‐competitively.

Formation and Color of Spinel Solid Solution in Li<sub>2</sub>O-MO-TiO<sub>2</sub> (M=Mg, Co, Ni) System

This study was concerned with the formation of spinel solid solutions and color development in the system Li2O-MO-3TiO2 (M=Mg, Co, Ni). Specimens were prepared by calcining mixtures of oxides of cobalt and titanium, and carbonates of lithium, magnesium and nickel at 1000°C for 2h. The formation range of spinel solid solutions was examined by X-ray analysis, and the lattice parameter of each solid solution was calculated. The structures of Li2O-MgO-3TiO2 and Li2O-CoO-3TiO2 solid solutions were refined by the pattern fitting method for powder X-ray diffraction. The color was discussed by measuring the spectral reflectance. The results were summarized as follows;1) In the system Li2O-(1-x)MgO-xCoO-3TiO2, a spinel solid solution with super structure was observed in the range of 0<x<1.2) In Li2O-(1-x)MgO-xNiO-3TiO2 and Li2O-(1-x)CoO-xNiO-3TiO2 systems, a spinel solid solution with super structure was obtained in the range of 0<x<0.6. When x=0.8 and x=1.0, the formation of spinels was not observed.3) According to the results of structure refinement [cubic, S. G.=P4332, Z=4, a=8.377 (M=Mg), 8.373 (M=Co) A], the cation distribution of Li2O-MO-3TiO2 (M=Mg, Co) is nearly Li0.5M0.5 [Li0.5Ti1.5]O4 (M=Mg, Co). Li+ and Ti4+ in octahedral sites have the 1:3 order. Between the separations of Li+-O2- and Ti4+-O2- in octahedral sites, a fairly large difference was noted, As Ni2+ revealed strong octahedral site preference, an increase in Ni2+ caused the migration of Li+ from octahedral to tetrahedral sites in Li2O-(Mg, Co, Ni)O-3TiO2 system. Consequently, the intensity of superlattice lines of spinel decreased as the amount of Ni2+ increased.4) The color of spinels changed from white to turquoise in Li2O-(1-x)MgO-xCoO-3TiO2 system, from white through light yellow to yellow in Li2O-(1-x)MgO-xNiO-3TiO2 system, and from turquoise through green to yellow in Li2O-(1-x)CoO-xNiO-3TiO2 system.

Ｚｎ｀２＋´及びＮｉ｀２＋´イオンとＳｉＯ２コロイドの共析挙動

The codeposition behavior of Zn2+, Ni2+ and SiO2 was investigated by a galvanostatic method using colloidal SiO2 (20nm). The SiO2 content of the electodeposits increased with the increase of Ni2+ content in the bath, and the amount of Ni2+ adsorbed on SiO2 particles was greater than the amount of Zn2+ adsorbed on SiO2 in the bath. Ni2+ played an important role on the deposition of SiO2. The relation between the amount of SiO2 in the bath and in the electrodeposit changed in accordance with Guglielmi's theory. Adsorption of the SiO2 on the cathode seems to occur in the first stage of the Zn-Ni-SiO2 electrodeposition process. A part of the SiO2 in the electrodeposit coagulated into larger particles during electrolysis because the pH on the cathode became higher than that of the electrolyte. The surface pH on the cathode during Zn-Ni-SiO2 electrodeposition measured by micro-Sb electrode was about 5-7 at a bath pH of 2, and a current density of 10-20A/dm2. This value coincided with the pH of the coagulation of SiO2. These results indicate that the factors controlling the codeposition of SiO2, Ni2+, and Zn2+ were: 1) adsorption of Ni2+ on the SiO2 in the bath; 2) adsorption of SiO2 on the cathode according to Guglielmi's theory; and 3) coagulation of SiO2 by the increase of pH on the cathode during electrolysis.