Growth of Pd particles in methanol synthesis over Pd/CeO2

The metal–support contact structure of Pd–CeO₂ changed with increasing the temperature of reduction. Upon high temperature reduction, severe sintering of Pd particles occurred, while sintering of the ceria support was marginal. The catalytic deactivation of the Pd/CeO₂ catalysts during methanol synthesis was caused by the further structural change in the Pd–CeO₂ contact under reaction conditions. Considerably large Pd particles (about 100 nm) were formed in the catalysts subjected to methanol synthesis, and there was a close correlation between the activity loss and the growth of the Pd particles. It was proposed that the structure of Pd–ceria contact shifted from small Pd clusters supported on ceria to sintered large Pd particles dispersed in a mass of ceria.     

Effect of Mixed Grain Sizes on the Thermoelectric Properties of Ca0.9Yb0.1MnO3

Ca_0.9Yb_0.1MnO₃ has been identified as a material that might be suitable for thermoelectric applications. We fabricated micro/nanograined Ca_0.9Yb_0.1MnO₃ composites, with the aim of controlling the passage of electrons and phonons simultaneously. Micro/nanograined Ca_0.9Yb_0.1MnO₃ composites containing various fractions of nanosized powder were prepared by sintering mixtures of microparticulate and nanoparticulate Ca_0.9Yb_0.1MnO₃, obtained by solid-state reaction and by gas-phase reaction, respectively. The electrical resistivity increased markedly when the weight fraction of nanosized powder exceeded 50%, probably as a result of a percolation phenomenon. However, the thermal conductivity was considerably reduced when the weight fraction of nanosized powder exceeded 25%, but then remained almost constant. The absolute values of the Seebeck coefficient of micro/nanograined Ca_0.9Yb_0.1MnO₃ composites were larger than those of monolithic micro- or nanograin Ca_0.9Yb_0.1MnO₃, probably as a result of the effects of potential-barrier scattering. The highest dimensionless figure of merit ZT value of 0.09 at 973 K was achieved with a sample containing 50% nanosized powder, and this value is 10% larger than that of monolithic micrograined Ca_0.9Yb_0.1MnO₃.     

Vitamin B6 suppresses serine protease inhibitor 3 expression in the colon of rats and in TNF-α-stimulated HT-29 cells

Scope: Previous reports in the areas of animal studies and, recently epidemiology, have linked anti‐tumorigenic and anti‐inflammatory effects to dietary vitamin B6. This study investigated the molecular mechanism of these effects of vitamin B6. Methods and results: DNA microarray analysis was used to obtain information on changes in colon gene expression from vitamin B6 (pyridoxine) repletion in vitamin B6‐deficient rats. Pyridoxine supplementation down‐regulated the inflammatory molecule, serine protease inhibitor clade A member 3 (SPI‐3) mRNA expression in the colon. This study also showed that tumor necrosis factor α (TNF‐α) induced SPI‐3 mRNA expression in HT‐29 human colon cancer cells, and vitamin B6 (pyridoxal hydrochloride) pretreatment of HT‐29 cells inhibited TNF ‐induced mRNA expression of SPI‐3. Vitamin B6 inhibited TNF‐α‐induced NF‐κB activation via suppression of IκBα degradation in HT‐29 cells. HT‐29 cells stably expressing epitope‐tagged ubiquitin were generated and vitamin B6 pretreatment was shown to inhibit ubiquitination of the IkB protein in response to TNF‐α‐i. Conclusion: Vitamin B6 suppressed SPI‐3 expression in the colon of rats and in TNF‐α‐stimulated HT‐29 cells. Further, this study showed a possible role of vitamin B6 in the regulation of protein ubiquitination.     

Preparation of porous particles by liquid–liquid interfacial crystallization

Liquid–liquid interfacial crystallization was proposed as a novel method of controlling crystal shape and size of precipitated solute particles. The crystallization was performed at interface forming two separate phases of aqueous solution and organic solvent in the present study, and progressed by increase of supersaturation caused by the slightly mutual diffusion at the liquid–liquid system. This crystallization process is possible to precipitate particles at room and constant temperature without cooling or heating sources. The liquid–liquid interfacial crystallization method was able to carry out in changing the shape of the interface.A spherical shape was made by droplets in the present liquid atomization process. Crystallization started when the droplets of the solution sprayed into the organic liquid. Our research involved producing glycine porous particles by atomizing glycine solution into 1-butanol and other organic solvent with 3-fluid nozzle. The collision between the solutions in compressed air produced the micro-size droplets of glycine solution. In using 1-butanol liquid, the glycine crystallized at the glycine solution/1-butanol interface. The spherical aggregated particles were obtained in this spray granulation process. In addition, the transformation occurred from unstable β-structure to metastable α-structure with changing crystallization condition, and it was found that α- and β-structure of glycine coexist in the obtained particles from observation by X-ray powder diffraction.     

Permeation of dissolved carbon dioxide in synthetic membranes

Permeability coefficients of dissolved carbon dioxide in poly(dimethyl siloxane), plasmatreated poly(dimethyl siloxane) membranes, and other membranes were measured by applying a carbon dioxide electrode in a liquid to liquid diffusion cell. The apparent permeability coefficients of carbon dioxide polystyrene, low density polyethylene, and nylon membranes in a liquid phase were observed to be higher than those in a gas phase due to a plasticizing effect of water molecules in the membranes. Boundary layer's resistance was estimated for plasma-treated and nontreated poly(dimethyl siloxane) membranes. The plasma treatment (10 W for 1 min in this study) which makes hydrophilic surfaces without change of bulk polymer properties was found to be effective to decrease the boundary layer's thickness and to increase the apparent permeability coefficient in the liquid phase.     

Antimicrobial activity and constituents in rumput roman extract as a natural food preservative

Rumput roman extract is used as a natural food preservative. Its antimicrobial activity and constituents were investigated as part of an ongoing study to evaluate its quality and safety as a food additive. The constituents were analyzed by GC/MS, and 5 major constituents were isolated and identified as capillin, capillene, caryophyllene oxide, alpha-curcumene and methyleugenol using NMR analysis. The antimicrobial activities against E. coli, S. cerevisiae and A. niger were measured by means of the halo test. Based on the results, we confirmed that capillin was the major active constituent. The concentrations of capillin and capillene were determined to 17.9 mg/mL and 36.1 mg/mL, respectively, from standard curves of authentic compounds on HPLC.     

Caspase inhibitors increase the rate of recovery of neural stem/progenitor cells from post-mortem rat brains stored at room temperature

To match the demand of regenerative medicine for nerve system, collection of stem cells from the post-mortem body is one of the most practical ways. In this study, the storage condition of the post-mortem body was examined. We prepared neural stem/progenitor cells (NSPCs) from post-mortem rat brains stored at different temperatures. When brains were stored at 4 °C, for one week, we were able to obtain neurospheres (a spheroid body containing NSPCs) by stimulation of cells with epidermal growth factor (EGF). Incremental increases in storage temperature decreased the rate of appearance of neurospheres. Within 48 h at 15 °C, 24 h at 25 °C, in both condition, we were able to recover NSPCs from post-mortem rat brains. At 15 °C, 90% of neurosphere-forming activity was lost within 24 h. However, even after 24 h at 25 °C, 2% neurosphere-forming activity remained. After 6 h of death, there was very little difference between the rates of NSPC recovery at 4 °C and 25 °C. Addition of caspase inhibitors to both the rat brain storage solution and the NSPC culture medium increased the rate of neurosphere-forming activity. In particular, an inhibitor of caspase-8 activity increased the NSPC recovery rate approximately three-fold, with no accompanying detrimental effects on neural differentiation in vitro.     

Inhibition of mitochondrial fragmentation during sake brewing causes high malate production in sake yeast

We previously demonstrated the presence and fragmentation of mitochondria during alcohol fermentation. Here, we show that Fis1p induces mitochondrial fragmentation, and inhibition of mitochondrial fragmentation causes higher malate production during sake brewing. These findings indicate that mitochondrial morphology affects the metabolism of constituents, providing a breeding strategy for high-malate-producing yeasts.     

Biochemical properties of acid-soluble collagens extracted from the skins of underutilised fishes

Acid-soluble collagens (ASCs) were extracted from the skins of several underutilised fishes, namely dusky spinefoot (Siganus fuscescens), sea chub (Kyphosus bigibbus), eagle ray (Myliobatis tobijei), red stingray (Dasyatis akajei) and yantai stingray (Dasyatis laevigata). The yields of the ASCs from skins of dusky spinefoot and sea chub were about 3.4–3.9%, and from ray species were about 5.3–5.7%, on a dry weight basis. According to the electrophoretic pattern, ASCs consisted of two different α-chains (α1 and α2) and were classified as type I collagen. However, the molecular weights of α2-chain for ray species were lower than those of bony fishes. ASC from ray species contained a higher content of imino acids than those from dusky spinefoot and sea chub. The denaturation temperatures (T_d) of ray species were about 33 °C, which was about 5 °C higher than those of dusky spinefoot and sea chub. The high T_d of ray species suggested the possibility of its utilisation as a substitute for mammalian collagen.     

Analysis of the constituents in jojoba wax used as a food additive by LC/MS/MS

Jojoba wax is a natural gum base used as a food additive in Japan, and is obtained from jojoba oil with a characteristically high melting point. Although the constituents of jojoba oil have been reported, the quality of jojoba wax used as a food additive has not yet been clarified. In order to evaluate its quality as a food additive and to obtain basic information useful for setting official standards, we investigated the constituents and their concentrations in jojoba wax. LC/MS analysis of the jojoba wax showed six peaks with [M+H]+ ions in the range from m/z 533.6 to 673.7 at intervals of m/z 28. After isolation of the components of the four main peaks by preparative LC/MS, the fatty acid and long chain alcohol moieties of the wax esters were analyzed by methanolysis and hydrolysis, followed by GC/MS. The results indicated that the main constituents in jojoba wax were various kinds of wax esters, namely eicosenyl octadecenoate (C20:1-C18:1) (1), eicosenyl eicosenoate (C20:1-C20:1) (II), docosenyl eicosenoate (C22:1-C20:1) (III), eicosenyl docosenoate (C20:1-C22:1) (IV) and tetracosenyl eiosenoate (C24:1-C20:1) (V). To confirm and quantify the wax esters in jojoba wax directly, LC/MS/MS analysis was performed. The product ions corresponding to the fatty acid moieties of the wax esters were observed, and by using the product ions derived from the protonated molecular ions of wax esters the fatty acid moieties were identified by MRM analysis. The concentrations of the wax esters I, II and III, in jojoba wax were 5.5, 21.4 and 37.8%, respectively. In summary, we clarified the main constituents of jojoba wax and quantified the molecular species of the wax esters without hydrolysis by monitoring their product ions, using a LC/MS/MS system.