Calciothermic reduction of NiO by molten salt electrolysis of CaO in CaCl2 melt

Metallic nickel powders with low and uniform residual oxygen content were produced from NiO using the molten salt electrolysis of CaO in CaCl₂ melt. Suitable amount of CaO for the reduction was in the range of 0.5–3.0 mol% CaO.The electrical isolation of NiO from both electrodes could produce metallic Ni in CaCl₂ melt. Separating the metal oxides from the cathode confirmed the mechanism of calciothermic reduction that the electrolysis of dissolved CaO in CaCl₂ melt produces Ca, and that the dissolved Ca in molten CaCl₂ successfully reduces NiO to metallic Ni. An average of about 600 ppm oxygen in Ni sample was achieved directly from oxide, when NiO was detached from the cathode.     

Electrically-switchable, permselective membranes prepared from nano-structured N-doped DLC

In this study, we report a fabrication of a conductive DLC through-hole membrane with highly ordered nanopore arrays by template synthesis using an anodic porous alumina and effects of intrinsic properties of DLC (a wide working potential range and low ion adsorption) on ion permselectivity when the membrane is applied to separate ions.We have successfully fabricated the conductive DLC membranes that have pore diameters ranging from 14 nm to 105 nm and show electrically tunable charge selectivity. With these membranes, fluxes of cations across the membrane can be reduced by applying positive potentials and can be increased by applying negative potentials. In the case of anions, a selectivity pattern opposite to cations was observed. Inside pore surfaces of the conductive DLC membrane could have excess charge by potentiostatically charging. This excess charge regulates ion transport across the membranes. The membranes reject ions of the same sign as excess charge and transport ions of the opposite sign. The permselectivity of the membrane can be reversibly switched from cation-permselective to anion-permselective by changing potentials applied to the membrane (because the signs of excess charge can be controllable by applied potentials).DLC membrane exhibited ion permselectivity even in an electrolyte solution including ions strongly adsorb to electrode surfaces such as Na₂SO₄ and HCl solutions. By using DLC membrane, ion permselectivity can be controlled in real samples commonly including adsorbing ions (that cannot be controlled with Au nanotubule membrane due to a specific adsorption to electrode surfaces).We could also demonstrate the permselectivity of target ions by controlling the potential applied to the membrane even in the mixed solution, which contains both cations and anions and is close to actual samples including ions aimed to be separated.     

Evaluation of SOFC anode polarization simulation using three-dimensional microstructures reconstructed by FIB tomography

In order to evaluate the numerical simulation method for solid oxide fuel cell anode polarization, three-dimensional lattice Boltzmann method simulation is carried out using Ni–YSZ microstructures reconstructed by a focused ion beam scanning electron microscope. The effects of reconstructed sample volume size on the three phase boundary length, tortuosity factors and overpotential are first investigated. The YSZ tortuosity factor has remained nearly unchanged when the cross-sectional area exceeds approximately 200 μm², while the pore tortuosity factor is almost independent of the sample volume size. On the other hand, the Ni tortuosity shows very large variation regardless of the sample volume size. The overpotential predicted with the largest volume size sample is slightly larger than those of smaller volume samples. Two exchange current models based on patterned electrodes are assessed presently. Both models give weaker dependence on the steam concentration than the experimental data. From the predicted three-dimensional current stream lines, it is found that the mirrored computational structure gives a thinner reactive layer because of the factitious connection of Ni phase. Thus, it is recommended to use larger volume size samples which can cover whole reactive thickness when discussing the local potential and flux distributions.     

Cholesterol-lowering activity of plant sterol-egg yolk lipoprotein complex in rats

Free plant sterols cannot be dissolved in oil or water. Using free plant sterols and egg yolks, we developed a plant sterol-egg yolk lipoprotein complex (PSY) that can be dispersed in water and considered suitable for use in processed foods. The cholesterol-lowering activity of PSY was equal to that of free plant sterols and plant sterol esters. Consumption of a freeze-dried PSY-containing omelet reduced serum and hepatic cholesterol concentrations. The results suggest that PSY has cholesterol-lowering activity equivalent to that of free plant sterols and plant sterol esters. Moreover, the cholesterol-lowering activity of PSY was maintained in processed foods.     

Enamides and enecarbamates as nucleophiles in stereoselective C-C and C-N bond-forming reactions

Because the backbone of most of organic compounds is a carbon chain, carbon-carbon bond-forming reactions are among the most important reactions in organic synthesis. Many of the carbon-carbon bond-forming reactions so far reported rely on nucleophilic attack of enolates or their derivatives, because those nucleophiles can be, in general, readily prepared from the corresponding carbonyl compounds. In this Account, we summarize the recent development of reactions using enamide and enecarbamate as a novel type of nucleophile. Despite their ready availability and their intrinsic attraction as a synthetic tool that enables us to introduce a protected nitrogen functional group, enamide and enecarbamate have rarely been used as a nucleophile, since their nucleophilicity is low compared with the corresponding metal enolates and enamines. A characteristic of enamides and enecarbamates is that those bearing a hydrogen atom on nitrogen are relatively stable at room temperature, while enamines bearing a hydrogen atom on nitrogen are likely to tautomerize into the corresponding imine form. Enamides and enecarbamates can be purified by silica gel chromatography and kept for a long time without decomposition. During the investigation of nucleophilic addition reactions using enamides and enecarbamates, it has been revealed that enamides and enecarbamates bearing a hydrogen atom on nitrogen react actually as a nucleophile with relatively reactive electrophiles, such as glyoxylate, N-acylimino ester, N-acylimino phosphonate, and azodicarboxylate, in the presence of an appropriate Lewis acid catalyst. Those bearing no hydrogen atom on nitrogen did not react at all. The products initially obtained from the nucleophilic addition of enamides and enecarbamates are the corresponding N-protected imines, which can be readily transformed to important functional groups, such as ketones by hydrolysis and N-protected amines by reduction or nucleophilic alkylation. In the nucleophilic addition reactions of enamides and enecarbamates to aldehydes, it was unveiled that the reaction proceeds stereospecifically, that is, (E)-enecarbamate gave anti product and (Z)-enecarbamate afforded syn product with high diastereoselectivity (>97/3). This fact can be rationalized by consideration of a concerted reaction pathway via a hydrogen-involved cyclic six-membered ring transition state. In the addition reactions to N-acylimino phosphonates, much higher turnover frequency was observed when enamides and enecarbamates were used as a nucleophile than was observed when silicon enolates were used. When silicon enolates were used, the intermediates bearing a strong affinity for the catalyst inhibited catalyst turnover, resulting in low enantioslectivity because of the dominance of the uncatalyzed racemic pathway. In the case of nucleophilic addition of enamides and enecarbamate, however, a fast intramolecular hydrogen transfer from the enecarbamate nitrogen may prevent the intermediate from trapping the catalyst for a long time, to afford the product with a high enantioselectivity. In conclusion, enamides and enecarbamates, although originally employed as just N-analogues to silicon enolates, have emerged as remarkably useful nucleophiles in a variety of Lewis acid-catalyzed reactions.     

Kluyveromyces marxianus-based platform for direct ethanol fermentation and recovery from cellulosic materials under air-ventilated conditions

Consolidated bioprocessing represents an attractive approach to converting cellulosic materials into bioethanol, yet is practically unavailable. We developed a ventilation-mediated, simultaneous ethanol fermentation and recovery system. Running the system under air-supplied conditions, apparently pure ethanol (28g) was recovered from cellobiose (100g) by growing recombinant Kluyveromyces marxianus expressing β-glucosidase.     

Changes of aquaporin 5-distribution during release and reaccumulation of secretory granules in isoproterenol-treated mouse parotid gland

Water channel aquaporin 5 (AQP5) is present in the apical membrane of the salivary gland acinar cells. We examined changes of AQP5-distribution during the fusion process of secretory granule membranes into the apical membrane and subsequent recovery process in the mouse parotid gland by administering isoproterenol (IPR) in vivo. We performed immunoperoxidase, immunofluorescence and immunoelectron microscopy. In the basal state, AQP5 was localized mainly in the apical membrane of the acinar cell. It was also present in the basolateral membrane to a lesser extent. When IPR was administered to mice, dot-like, vesicle-like and vacuole-like labeling for AQP5 was seen in the subapical regions by light microscopy. By immunoelectron microscopy, AQP5 was localized at both the apical and basolateral plasma membranes in the basal state. At 5 and 30 min after the IPR-administration, acinar lumen became enlarged and small invaginations formed by fusion of secretory granules were seen. AQP5 was positive along the apical plasma membrane and its small invaginations. At 60 min, large invaginations of the lumen were formed. AQP5 remained positive in the membrane of these large invaginations. At 6 h, large invaginations disappeared and AQP5 was localized in the apical plasma membrane. AQP5 was restricted to plasma membranes and continuous invaginations formed by the exocytosis of secretory granules. AQP5 was not detected in the cytoplasm. These observations show that AQP5 does not seem to be endocytosed during the membrane recycling process following the exocytosis.