Purification and Characterization of a Maltotriogenic α-Amylase I and a Maltogenic α-Amylase II Capable of Cleaving α-1,6-Bonds in Amylopectin

Extracellular α-amylases I and II, produced by a facultative thermophile Bacillus thermoamyloliquefaciens KP 1071 capable of growing at 30–66°C, were purified to homogeneity. α-Amylase I consisted of a single polypeptide with methionine residue at the NH₂-terminus. α-Amylase II consisted of two equivalent polypeptides each comprising a methionine at the NH₂-terminus. α-Amylase I hydrolyzed endotypically α-1,4-bonds in glycogen, amylopectin and β-limit dextrin, but not their α-1,6-bonds. α-Amylase II degraded amylopectin and β-limit dextrin in exo-fashion by cleaving preferentially α-maltose units from the non-reducing ends and hydrolyzing their α-1,6-branch points. α-Amylase II hydrolyzed maltotriose, phenyl-α-maltoside, α- and β-cyclodextrins and pullulan, whereas α-amylase I had no activity for all these sugars. α-Amylases I and II hydrolyzed maltotetraose, maltopentaose, α-limit dextrin and amylose, but they were inactive for maltose, isomaltose and panose. It was suggested that α-amylase I is the most thermostable type of hitherto known maltotriogenic endo-acting α-amylases, and α-amylase II is the first maltogenic exo-acting α-amylase able to split α-1,6-bonds in amylopectin.     

Safety aspects of the combined HTTR/steam reforming complex for nuclear hyrogen production

The High-Temperature Engineering Test Reactor (HTTR) in Oarai, Japan, has the potential to demonstrate the production of hydrogen by steam reforming and using nuclear process heat as primary energy input. Particular safety aspects for such a combined nuclear/chemical complex have been investigated such as fire and explosion hazard at presence of flammable gases (LNG, H₂, CO) near the reactor building. A methane vapor cloud in the open atmosphere or partially obstructed areas is highly unlikely to detonate and damage the reactor building. Theoretical assessments and experimental studies significant to the HTTR-steam reforming system, include the spreading and combustion behavior of cryogens and flammable gases providing the basis for a comprehensive safety analysis of the nuclear/chemical facility.     

Quantitative Elemental Analysis of a Single Cell by Using Inductively Coupled Plasma-Mass Spectrometry in Fast Time-Resolved Analysis Mode

The elemental composition of a single yeast, green alga, or red blood cell (RBC) was precisely determined by using inductively coupled plasma-mass spectrometry (ICP-MS) operating in fast time-resolved analysis (TRA) mode. The technique is known as single-cell (SC)-ICP-MS. Phosphorus, sulfur, magnesium, zinc, and iron were detected in the three types of cell. The elemental composition of yeast and green alga obtained by SC-ICP-MS was consistent with results obtained from conventional ICP-MS measurements following acid digestion of the cells. Slight differences were found in the measured values between SC-ICP-MS and the conventional ICP-MS results for RBC. However, the SC-ICP-MS results for S and Fe in RBC were closer to the estimated values for these elements that were calculated from the level of hemoglobin in RBCs. The data suggest that SC-ICP-MS is suitable for the analysis of various cell types, namely, fungus, plant, and animal cells.     

Biosynthesis of PP-V, a monascorubramine homologue, by Penicillium sp. AZ

The biosynthetic pathway of PP-V, a new monascorubramine homologue, was elucidated by 13C-labeling studies. The [1-13C] of acetate was incorporated into 2-, 3a-, 4a-, 6-, 8-, 9-, 11-, 13-, 15-, 17-, and 19-Cs of PP-V, and the [2-13C], into 3-, 4-, 5-, 8a-, 9a-, 10-, 12-, 14-, 16-, 18-, and 20-Cs. These incorporation patterns coincide with those reported in the biosynthesis of a Monascus azaphilone pigment, monascorubrin.     

Distribution of higher-order structures in injection-molded polypropylenes

Flexural test specimens were injection-molded from six homoisotactic polypropylenes with MFI = 0.49-25.1 dg/min under cylinder temperatures of 200-320°C. Distributions in the flow direction of higher-order structures such as crystallinity X_c, thickness of skin layer, a*-axis-oriented component fraction [A*], and crystalline orientation functions and distributions in the thickness direction of higher-order structures such as X_c, β-crystal contents, [A*], and crystalline orientation functions were studied. These higher-order structures are inhomogeneous in the flow and thickness directions, which strongly influences the product properties such as mechanical and thermal properties. Molecular orientation process in injection molding was theoretically analyzed from a viewpoint of growth of recoverable shear strain at the gate and its relaxation in the cavity, which could considerably well explain the variations in the flow and thickness directions of the quantities such as thickness of the skin layer and crystalline orientation functions which express the degree of molecular orientation.     

N.m.r. study of egg yolk lecithin in aromatic solvents. Magnetic nonequivalence in the methylene protons of the fatty acyl chains

¹H and ¹³C n.m.r. chemical shifts and also spin-lattice relaxation times of phospholipids, mainly egg yolk lecithin, were measured in organic solvents, especially aromatic solvents. The use of aromatic solvents promotes the difference in the magnetic shielding environment of the internal methylene protons of the fatty acyl chains and as a result, a doublet peak for the methylene groups was observed in the solvents, especially mesitylene. The ¹H and ¹³C n.m.r. T₁ measurements indicate the remarkable gradient in the motional freedom along the fatty acyl chains as well as the marked decrease in the motional freedom of the polar head group and also, the high-field component of the doublet peak for internal methylene protons has a shorter T₁ value than the low-field component. Thus, it was concluded that the low-field component in the doublet comes from the methylene protons located relatively in the neighbourhood of the carbonyl groups and the high-field component the methylene protons located relatively in the neighbourhood of the terminal methyl groups of the fatty acyl chains.     

The dilute solution properties of maleic anhydride and maleic acid copolymers: 1. Light scattering, osmotic pressure and viscosity measurements

Dilute solution behaviour of poly(maleic anhydride-co-ethyl vinyl ether) and poly(maleic acid-co-ethyl vinyl ether) has been investigated by light scattering, osmotic pressure, and viscosity measurements. The molecular weights ($\text{M}\text{?}{}_{\mathrm{w}}$ and $\text{M}\text{?}{}_{\mathrm{n}}$), the second virial coefficients A₂, and the intrinsic viscosities [η] have been determined for three states of this copolymer: anhydride-form, H-form, and Na-salt independently. The constants in the Mark-Houwink relations were obtained for the above three states under different solvent conditions. The molecular weight of the anhydride-form is found to be higher than that of the acid-form or the Na-salt, suggesting the degradation in a process of hydrolysis. The second virial coefficient A₂ as well as the Mark-Houwink relation indicates that the anhydride-form and H-form behave as flexible polymer chains in good solvents. However, the polymer coil of Na-salt is highly expanded even at saturated NaCl concentration.     

Hydrothermal Corrosion of Alumina Ceramics

The corrosion behavior and strength degradation of alumina ceramics with 99%, 99.9%, and 99.99% Al₂O₃ were studied in water at 300°C and 8.6 MPa for 1 to 10 d. The weight loss in alumina ceramics was mainly attributed to the dissolution of SiO₂ and Na₂O grain-boundary impurities. Intergranular corrosion proceeded in the alumina ceramics by preferential attack at the grain boundaries. The extent of the strength reduction for corroded alumina ceramics was related to the impurity level in the alumina ceramics.     

Optical and adhesive properties of composite silica-impregnated Ca-α-SiAlON:Eu2+ phosphor films prepared on silica glass substrates

The compaction of a Eu-doped Ca-α-SiAlON phosphor powder was performed by electrophoretic deposition (EPD). The effect on the adhesion and optical properties of the silica precursor as both a binder of the powder and a filler of the air voids were evaluated. The adhesion of the silica impregnated composite film to the silica glass substrate was characterized by the tape test. The improvement of the external quantum efficiency was confirmed from the PL spectra measurement after the silica impregnation. The temperature dependence of the external quantum efficiency was also investigated in order to discuss the advantage of using the silica precursor as a binder for high-brightness LED applications.