Diffusion of m-sulfobenzoic acid in nylon 6

Diffusion of m-sulfobenzoic acid in nylon 6 was measured by using the S-35 labelled acid as a tracer. A multimodal mechanism, identical to that in a preceding paper on sorption, was assumed, according to which the protonated acid diffused by dissolution, and the two dissociated acids diffused by competitive interaction with the charged sites in nylon 6. The concentration dependence of the diffusion coefficients was explained by the chemical potential gradient model. The monobasically dissociated species was found to be dominant in the diffusion process. Diffusion coefficients and the activation energies of diffusion did not vary significantly with pH.     

A proposal for diesel spray model using a TAB breakup model and discrete vortex method

A hybrid model consisting of a modified TAB (Taylor Analogy Breakup) model and DVM (Discrete Vortex Method) is proposed for numerical analysis of the evaporating spray phenomena in diesel engines. The simulation process of the hybrid model is divided into three steps. First, the droplet breakup of injected fuel is analyzed by using the modified TAB model. Second, spray evaporation is calculated based on the theory of Siebers’ liquid length. The liquid length analysis of injected fuel is used to integrate the modified TAB model and DVM. Lastly, both ambient gas flow and inner vortex flow of injected fuel are analyzed by using DVM. An experiment with an evaporative free spray at the early stage of its injection was conducted under in-cylinder like conditions to examine an accuracy of the present hybrid model. The calculated results of the gas jet flow by DVM agree well with the experimental results. The calculated and experimental results all confirm that the ambient gas flow dominates the downstream diesel spray flow.     

Function of second glucan binding site including tyrosines 54 and 101 in Thermus aquaticus amylomaltase

Amylomaltase from Thermus aquaticus catalyzes three types of transglycosylation reaction, as well as a weak hydrolytic reaction of alpha-1,4 glucan. From our previous study [Fujii et al., Appl. Environ. Microbiol., 71, 5823-5827 (2005)], tyrosine 54 (Y54) was identified as an amino acid controlling the reaction specificity of this enzyme. Since Y54 is not located around the active site but in the proposed second glucan binding site that is 14 A away from catalytic residues, the functions of Y54 and the second glucan binding site are of great interest. In this study, we introduced mutations into another tyrosine (Y101) in the second glucan binding site. The obtained mutated enzymes were subjected to all four types of enzyme assay and the effects of mutations on the reaction specificities of these enzymes were comprehensively investigated. These studies indicated that the amino acid substitution at Y54 or Y101 for removing their aromatic side chain increases cyclization activity (intra-molecular transglycosylation reaction) but decreases disproportionation, coupling and hydrolytic activities (inter-molecular reactions). The superimposition of the reported structures of the enzyme with and without substrate analog revealed the occurrence of a conformational change in which a donor binding site becomes open. From lines of evidence, we conclude that the binding of glucan substrate to the second glucan binding site through an interaction with the aromatic side chains of Y54 and Y101 is a trigger for the enzyme to take a completely active conformation for all four types of activity, but prevents the cyclization reaction to occur since the flexibility of the glucan is restricted by such binding.     

Differential selectivity of natural and synthetic aminoglycosides towards the eukaryotic and prokaryotic decoding A sites

The lack of absolute prokaryotic selectivity of natural antibiotics is widespread and is a significant clinical problem. The use of this disadvantage of aminoglycoside antibiotics for the possible treatment of human genetic diseases is extremely challenging. Here, we have used a combination of biochemical and structural analysis to compare and contrast the molecular mechanisms of action and the structure-activity relationships of a new synthetic aminoglycoside, NB33, and a structurally similar natural aminoglycoside apramycin. The data presented herein demonstrate the general molecular principles that determine the decreased selectivity of apramycin for the prokaryotic decoding site, and the increased selectivity of NB33 for the eukaryotic decoding site. These results are therefore extremely beneficial for further research on both the design of new aminoglycoside-based antibiotics with diminished deleterious effects on humans, as well as the design of new aminoglycoside-based structures that selectively target the eukaryotic ribosome.     

全库铺设沥青混凝土面板水库的抗震设计

介绍在建中日本最大规模的全库铺设沥青混凝土面板水库的抗震设计。基于水库所处的地形、地质及堤体填筑条件，酋先对水库整体进行三维有限元动力分析，从总体上掌握水库的地震反应特性；然后对变形较大的断面进行详细的二维动力分析，获得面板的最大动应变。同时，通过大量室内试验，确定满足施工要求的沥青混凝土配合比及其物理力学特性。根据面板的材料特性及其构造特点，提出二级抗震设防的极限状态设计法，并对该水库面板的抗震性能进行校核。     

Phosphorylation of starch and dextrin by dry‐heating in the presence of phosphate,and their calcium phosphate‐solubilizing ability

Starch and dextrin were phosphorylated by dry‐heating in the presence of phosphate, and their properties were examined. The phosphorylation of starch was accelerated with decreasing moisture, rising incubation temperature and prolongation of the incubation period. However, a rise in incubation temperature, and lengthened incubation period caused increased browning and degradation. A decrease in the pH from 5.5 to 3.0 resulted in a modest increase of phosphorylation, but also marked browning and degradation. When potato starch was phosphorylated at 140°C and pH 5.5 for 24 h, its phosphorus content was increased up to 3.47%, with fewer side reactions. Phosphorlylated starch and dextrin had calcium phosphate‐solubilizing abitity. Phosphorylated dextrin with 2.42% phosphorus had about half the calcium phosphate‐solubilizing ability of casein phosphopeptide (CPP). The possibility of substituting of phosphorylated starch and dextrin for CPP as a calcium phosphate‐absorption enhancing material is discussed herein.     

Al-laminated film packaged organic radical battery for high-power applications

A 100-mAh class of aluminum-laminated film packaged organic radical battery with a poly(2,2,6,6-tetramethyl-1-piperidinyloxy-4-yl methacrylate) (PTMA) composite cathode and a graphite anode has been fabricated. Its total weight was 22 g and the thickness was 4.3 mm. Because PTMA comprised only 6.2% of the total cell weight, the energy density was considerably less than that of a lithium ion battery. However, the power density per active material weight was found to be better than that of lithium ion battery. The applications which require high-power capability rather than high-energy density, such as the sub-battery in electronic devices and motor drive assistance in electric vehicles, would be appropriate for organic radical batteries in the future.     

Preparation and evaluation of Cu2ZnSnS4 thin films by sulfurization of E---B evaporated precursors

By sulfurization of E---B evaporated precursors, CZTS(Cu₂ZnSnS₄) films could be prepared successfully. This semiconductor does not consist of any rare-metal such as In. The X-ray diffraction pattern of CZTS thin films showed that these films had a stannite structure. This study estimated the optical band gap energy as 1.45 eV. The optical absorption coefficient was in the order of 10⁴cm⁻¹. The resistivity was in the the order of 10⁴ Ω cm and the conduction type was p-type. Fabricated solar cells, Al/ZnO/CdS/CZTS/Mo/Soda Lime Glass, showed an open-circuit voltage up to 400 mV.     

Glucosylceramide Changes Bacterial Metabolism and Increases Gram-Positive Bacteria through Tolerance to Secondary Bile Acids In Vitro

Glucosylceramide is present in many foods, such as crops and fermented foods. Most glucosylceramides are not degraded or absorbed in the small intestine and pass through the large intestine. Glucosylceramide exerts versatile effects on colon tumorigenesis, skin moisture, cholesterol metabolism and improvement of intestinal microbes in vivo. However, the mechanism of action has not yet been fully elucidated. To gain insight into the effect of glucosylceramide on intestinal microbes, glucosylceramide was anaerobically incubated with the dominant intestinal microbe, Blautia coccoides, and model intestinal microbes. The metabolites of the cultured broth supplemented with glucosylceramide were significantly different from those of broth not treated with glucosylceramide. The number of Gram-positive bacteria was significantly increased upon the addition of glucosylceramide compared to that in the control. Glucosylceramide endows intestinal microbes with tolerance to secondary bile acid. These results first demonstrated that glucosylceramide plays a role in the modification of intestinal microbes.     

Hill Plot Focusing on Ce Compounds with High Magnetic Ordering Temperatures and Consequent Study of Ce<Subscript>2</Subscript>AuP<Subscript>3</Subscript>

The Hill plot is a well-known criterion of the f-electron element interatomic threshold distance separating the nonmagnetic state from the magnetic state in actinides and lanthanides. We have reinvestigated the Hill plot of Ce compounds using the commercial crystallographic database CRYSTMET, focusing on a relationship between the Ce-Ce distance and the magnetic ordering temperature because a Ce compound with no other magnetic elements rarely has a magnetic ordering temperature that is higher than 20 K. The Hill plot of approximately 730 compounds has revealed that a Ce compound, particularly a ferromagnet, showing a high magnetic ordering temperature would require a short Ce-Ce distance with a suppression of the valence instability of the Ce ion. From the study, we developed interest in Ce₂AuP₃ with a Curie temperature of 31 K. The ferromagnetic nature of this material has been examined in terms of a doping effect, which suggests a possible increase in magnetic anisotropy energy.