Photocatalytic Property and Electronic Structure of Lanthanide-based Oxysulfides

Lanthanide-based oxysulfides and sulfide, LnTaO_3.5S_0.5, Ln₁₀OS₁₄ (Ln = La, Pr, Nd, Sm) and La₄In₅S₁₃, were successively synthesized by sulfurization in a flowing H₂S. The sulfurization decreased the band-gap energies from >4 eV to <3eV, because of the formation of occupied S3p orbitals on the top of valence band. In accordance with the small band gap, the H₂ evolution from a 0.01 M Na₂S and 0.01 M Na₂SO₃ solution system was observed under irradiation of light up to >500 nm. The rate of H₂ evolution under light irradiation of >500 nm increased in the order of Ni/LaTaO_3.5S_0.5 < Ru/La₁₀OS₁₄ < Pt/La₄In₅S₁₃.     

Formation of low-resistivity poly-Si and SiNx films by Cat-CVD for ULSI application

In this paper, bulk-Si metal–oxide–semiconductor field effect transistors (MOSFETs) are fabricated using the catalytic chemical vapor deposition (Cat-CVD) method as an alternative technology to the conventional high-temperature thermal chemical vapor deposition. Particularly, formation of low-resistivity phosphorus (P)-doped poly-Si films is attempted by using Cat-CVD-deposited amorphous silicon (a-Si) films and successive rapid thermal annealing (RTA) of them. Even after RTA processes, neither peeling nor bubbling are observed, since hydrogen contents in Cat-CVD a-Si films can be as low as 1.1%. Both the crystallization and low resistivity of 0.004 Ω·cm are realized by RTA at 1000 °C for only 5 s. It is also revealed that Cat-CVD SiN_x films prepared at 250 °C show excellent oxidation resistance, when the thickness of films is larger than approximately 10 nm for wet O₂ oxidation at 1100 °C. It is found that the thickness required to stop oxygen penetration is equivalent to that for thermal CVD SiN_x prepared at 750 °C. Finally, complementary MOSFETs (CMOSs) of single-crystalline Si were fabricated by using Cat-CVD poly-Si for gate electrodes and SiN_x films for masks of local oxidation of silicon (LOCOS). At 3.3 V operation, less than 1.0 pA μm⁻¹ of OFF leakage current and ON/OFF ratio of 10⁷–10⁸ are realized, i.e. the devices can operate similarly to conventional thermal CVD process.     

Phase separation behavior and morphology development of phenolic resin/PMMA/hexamethylenetetrarnine blends

Summary In order to obtain materials with nanopores which will be applicable for many fields, the structures of the cured blends of phenolic resin (PhN), poly(methyl methacrylate) (PMMA) and curing agent were studied. After PMMA was extracted from cured blends, the structures of cured phenolic resins were observed with SEM. As a results, it was found that nanosized continuous pore structures were formed in extremely wide composition region if curing temperature was high.     

The Influence of Ethanol on the Foaming Properties of Beer Protein Fractions: A Comparison of Rudin and Microconductivity Methods of Foam Assessment

The effect of ethanol on the foaming properties of beer protein fractions was studied using a microconductivity method and nitrogen gas to generate the foam. Increasing the ethanol concentration resulted in a decrease in foam stability. Interfacial studies including thin film drainage and dilational elasticity measurements indicated that ethanol reduced the rigidity of the adsorbed protein layer resulting in accelerated drainage from the foam lamellae and increased probability of film rupture. These results conflict with data from the Rudin method (using nitrogen gas to generate the foam) which indicate that, at low concentration, ethanol improves foam stability. These apparently conflicting results may be explained by the foam positive effects of a decline in bubble size and increase in bulk viscosity observed for the Rudin method, contrasted with the negative influence of a reduction in surface viscosity observed for the microconductivity foam assessment method.     

Selective enumeration of viable Enterobacteriaceae and Pseudomonas spp. in milk within 7 h by multicolor fluorescence in situ hybridization following microcolony formation

Rapid and simultaneous enumeration of viable Enterobacteriaceae and viable Pseudomonas spp. in milk was achieved by using multicolor fluorescence in situ hybridization (FISH) with oligonucleotide probes based on 16S ribosomal RNA (rRNA) sequences in combination with a microcolony growth method (multicolor microcolony-FISH; MMC-FISH). The procedure of MMC-FISH method is rather simple; that is milk clearing, filtration of cells, incubation, hybridization and enumeration. Enumeration of targeted bacteria in logarithmic growth phase, stationary phase, or in a starved state in milk by MMC-FISH required 5-7 h, while it took 1-3 days to test for Escherichia coli and Pseudomonas putida by the conventional culture method. The numbers of E. coli and P. putida in each phase or in a starved state in milk determined by MMC-FISH were almost the same or greater than the number of colony forming units determined by the plate counting method. The MMC-FISH allows rapid examination of contamination in milk by viable Enterobacteriaceae and Pseudomonas spp. with growth potential.     

Regiospecific analysis by ethanolysis of oil with immobilized <Emphasis Type="Italic">Candida antarctica</Emphasis> lipase

A mixture of oil/ethanol (1∶3, w/w) was shaken at 30°C with 4% immobilized Candida antarctica lipase by weight of the reaction mixture. The reaction regiospecifically converted FA at the 1- and 3-positions to FA ethyl esters, and the lipase acted on C₁₄−C₂₄ FA to a similar degree. The content of 2-MAG reached a maximum after 4 h; the content was 28–29 mol% based on the total amount of FA in the reaction mixture at 59–69% ethanolysis. Only 2-MAG were present in the reaction mixture during the first 4 h, and 1(3)-MAG were detected after 7 h. After removal of ethanol from the 4-h reaction mixture by evaporation, 2-MAG were fractionated by silica gel column chromatography. The contents of FA in the 2-MAG obtained by ethanolysis of several oils coincided well with FA compositions at the 2-position, which was analyzed by Grignard degradation. It was shown that ethanolysis of oil with C. antarctica lipase can be applied to analysis of FA composition at the 2-position in TAG.     

Preparation of regioisomers of structured TAG consisting of one mole of CLA and two moles of caprylic acid

TAG (MLM) with medium-chain FA (MCFA) at the 1,3-positions and long-chain FA (LCFA) at the 2-position, and TAG (LMM) with LCFA at the 1(3)-position and MCFA at 2,3(1)-positions are a pair of TAG regioisomers. Large-scale preparation of the two TAG regioisomers was attempted. A commercially available FFA mixture (FFA-CLA) containing 9-cis, 11-trans (9c, 11t)- and 10t,12c-CLA was selected as LCFA, and caprylic acid (C₈FA) was selected as MCFA. The MLM isomer was synthesized by acidolysis of acyglycerols (AG) containing two CLA isomers with C₈FA: A mixture of AG-CLA/C₈ FA (1∶10, mol/mol) and 4 wt% immobilized Rhizomucor miehei lipase was agitated at 30°C for 72 h. The ratio of MLM to total AG was 51.1 wt%. Meanwhile, LMM isomer was synthesized by acidolysis of tricaprylin with FFA-CLA: A mixture of tricaprylin/FFA-CLA (1∶2, mol/mol) and 4 wt% immobilized R. miehei lipase was agitated at 30°C for 24 h. The ratio of LMM to total AG was 51.8 wt%. MLM and LMM were purified from 1,968 and 813 g reaction mixtures by stepwise short-path distillation, respectively. Consequently, MLM was purified to 92.3% with 49.1% recovery, and LMM was purified to 93.2% with 52.3% recovery. Regiospecific analyses of MLM and LMM indicated that the 2-positions of MLM and LMM were 95.1 mol% LCFA and 98.3 mol% C₈ FA, respectively. The results showed that a process comprising lipase reaction and short-path distillation is effective for large-scale preparation of high-purity regiospecific TAG isomers.     

Simple evaluation of aortic arch calcification by chest radiography in hemodialysis patients

Vascular calcification is associated with a poor prognosis in dialysis patients. It can be assessed with computed tomography but simple inoffice techniques may provide useful information. We compared the results obtained with a simple noninvasive technique with those obtained using multidetector computed tomography for aortic arch calcification volume (AoACV) in chronic hemodialysis (HD) patients. The enrolled study subjects were 63 (32 men and 31 women) maintenance HD patients. Calcification of the aortic arch was semiquantitatively estimated with a AoAC score (AoACS) on plain chest radiology. The AoACV was increased, with a mean value of 6.6 ranging from 0% to 36.5%. The coefficient of intraobserver variation was less than 2.5%. Aortic arch calcification score was highly correlated with AoACV (r=0.635, P<0.001). Multiple regression analysis showed age (F value=12.62, P<0.001) and pulse pressure (F value=4.54, P=0.037) to be significant independent determinants of AoACS. In conclusion, a simple measurement of AoACS may be useful for inoffice imaging to choose a therapeutic regimen in HD patients.     

Effect of inorganic salts,amino acids and proteins on the degradation of pure magnesium in vitro

The possibility of magnesium and its alloys in medical applications is actively investigated in these days for the realization of biodegradable metallic devices. However, the degradation behavior and mechanisms of magnesium and its alloys in physiological environment such as inside the human body have not been elucidated. In this study, we performed 14-d long immersion tests of pure magnesium (3N) in 4 kinds of physiological solutions simulating the body fluids to examine the effects of the chemical components of the body fluids on the degradation of magnesium. The degradation rate of pure magnesium was strongly influenced by the kinds of the solution used. The highest degradation rate was obtained in NaCl, followed by E-MEM, Earle's solution, and E-MEM+FBS. The average degradation rate in NaCl for 8–14 d is about 100 times larger than that in E-MEM+FBS, which is the closest solution to human blood plasma. These results show that protein adsorption and insoluble salt formation retarded magnesium degradation, whereas organic compounds such as amino acids encourage the dissolution of magnesium. Buffering the solution also influenced the degradation rate; buffering NaCl with HEPES increased the degradation rate but buffering with NaHCO₃ decreased it. Based on these results, the use of appropriate solution such as E-MEM+FBS is important for in vitro evaluation of the magnesium degradation rate under the physiological environment simulating inside the human body.     

Development of rapid hygrothermal pasteurization using saturated water vapor

We developed a novel rapid hygrothermal pasteurization (RHP) method using saturated water vapor with a dew point of 100 °C. In the present study, the effects of RHP on microbiological quality and quality attributes such as color changes, firmness and ascorbic acid content on many fresh-cut fruits and vegetables (cabbage, cucumber, carrot, cherry tomato, bell pepper, strawberry, pineapple and melon) were investigated. The RHP was performed within a second by free-falling samples through a cylindrical processing chamber filled with steam. The RHP resulted in a 0.7–2.0 log order reduction in the numbers of naturally inoculated mesophilic bacteria. Furthermore, the RHP induced no significant changes in color and firmness of samples, except on the leafy vegetable, cabbage. Ascorbic acid was also retained approximately 80% and above. These results indicate that the RHP is a clean and effective method for decontaminating mesophilic bacteria on fresh fruits and vegetables with minimal changes in quality.Industrial relevanceIn fresh-cut industry, an effective and risk-free decontamination technology is required for use in place of a conventional method, washing by chlorine that can produce carcinogenic chlorinated by-products. In this study, the rapid hygrothermal pasteurization (RHP) method using saturated water vapor was invented and their ability for applying minimal processing was evaluated. The results showed that RHP, without using chemicals, can reduce microorganism load and preserve quality attributes in many kinds of fresh-cut fruits and vegetables. Therefore, RHP could be used as a novel method, which can be generally applicable to fresh-cut fruits and vegetables in the food industry.