Spore fatty acid composition in Bacillus natto, a food microorganism

The levels of fatty acids and their distribution were determined in spores from twenty-five strains of Bacillus natto isolated from a fermented soybean food, natto, or subcultured from the culture collection. The major fatty acid components of spores, consisting of about 80 to 90% of the total, were anteiso-C₁₅, anteiso-C₁₇, iso-C₁₅ and iso-C₁₇; the other fatty acids, at a level of 10 to 20% of the total, were iso-C₁₄, iso-C₁₆, n-C₁₄, n-C₁₆ and n-C₁₈. The amount of fatty acid in spores was highest with anteiso-C₁₅, followed in order by iso-C₁₅. In addition to the nine fatty acids, some of the strains produced six extra fatty acids, three branched (anteiso-C₁₃, iso-C₁₂ and iso-C₁₃) and three normal (n-C₁₂, n-C₁₅ and n-C₁₇).     

Quadratic Discriminant Analysis of Cephalo-Pelvic Disproportion

Behaviormetrika - To construct the discriminant function for the diagnosis of CPD, the equality of the two covariance matrices were studied. Two were different significantly, which means the use of...     

On the intergranular fracture mechanism due to ledge formation in an Al-6.0% Zn-2.5% Mg alloy

The ledges observed on the over-load fracture surfaces of an Al-6.0% Zn-2.5% Mg alloy variously heat treated are discussed. As pointed out by Ryum and Baardseth the ledges are formed by the reaction between slip bands and grain boundaries. The morphology of the ledges changes from a sharp saw-toothed to a sine-curved shape, and the facets of the ledges vary from a flat face to a dimpled one with the degree of ageing. Grain-boundary precipitates were frequently observed on the flat facets. The fracture stress, calculated from a modified equation of Stroh's theory, supports the possibility of fracture occurring at a stress a little beyond yielding.     

On the effect of cyclic stress ratio on the fatigue crack propagation

A new model of fatigue crack propagation is proposed which takes the effect of cyclic stress ratio into account. In the model it is assumed that the fatigue crack propagation rate is proportional to the absorbed hysterisis energy per stress cycle at the tip of a crack. The energy is calculated from stress field resulting from the Dugdak-Barenblatt Model and strain field from an experimental result. The model was applied to analyse the experiments on several materials.     

A statistical interpretation of fatigue limit on the basis of the extreme theory

The theoretical consideration of the scatter of fatigue limit was made on the basis of the theory of extreme value. And then, the experimental examination on this theory was conducted through the various fatigue tests on induction-hardened low carbon steel specimens. As the results, it was found that the theory of extreme value is applicable to the interpretation of the scatter of fatigue limit.     

Formation of hydrogen-capped polyynes by laser ablation of C60 particles suspended in solution

Laser ablation of C₆₀ particles suspended in hexane or methanol solution has been studied using a Nd:YAG laser (266, 355, 532, and 1064 nm). Insoluble product analysis by Raman spectroscopy showed that C₆₀ particles transformed to graphite-like ones. On the other hand, soluble product analysis by HPLC coupled with UV absorption spectroscopy and GC/MS demonstrated that linear hydrogen-capped polyynes (C_nH₂: n=8, 10, 12) were formed. The dominant C_nH₂ polyyne was C₈H₂ in all cases. The relative abundance of polyynes decreased with increasing wavelength of the Nd:YAG laser, except for 266-nm irradiation in hexane, where the relative abundance of polyynes at 355 nm was greater than that at 266 nm. It was therefore concluded that photochemical processes are more important than thermal ones for the formation of polyynes. The relative abundance of polyynes in hexane was greater than that in methanol. The dependence of relative abundance of polyynes on the particles concentration, laser irradiation time, and laser power was measured in order to obtain information on formation mechanism of polyynes. These results and reported laser photochemical processes of C₆₀ molecules in the gas phase suggested that C₂ radicals produced from C₆₀ are polymerized and hydrogenated to form C₈H₂ and much smaller amounts of C₁₀H₂ and C₁₂H₂.     

The electric conductivity of poly(ethyl vinyl ketone) film reacted with phosphoryl chloride

Summary The reaction of poly (ethyl vinyl ketone) with active chlorides in petroleum ether was followed by the electric conductivity measurement. Phosphoryl chloride was found to be an effective reagent to produce a highly conjugated system with an apparent specific conductivity of the order of 10^{–2 –1}cm^–1 in petroleum ether. The reaction temperature seems to be important for the electric conductivity of the product, the higher the reaction temperature, the lower the electric conductivity of the reacted film.     

An equation for estimating the diffusion coefficient of electrolytes in ion exchange membranes

When operating electrodialysis equipment with ion exchange membranes, the diffusion coefficient in the membrane must be predetermined. We derived an equation to estimate the diffusion coefficient with only one unknown factor by assuming that the mobility of counter-ions in the membrane was proportional to that in the solution.The diffusion experiments were studied by a stirring cell method. The value of an apparent permeability coefficient became constant after 7200 seconds. The value was approximately equal to that of the permeability coefficient in the membrane at 200 rpm. The diffusion coefficients in the membranes were obtained for various electrolytes. The unknown factor was determined by comparing the theoretical with the experimental value of the diffusion coefficient, and a final equation to estimate the diffusion coefficient was derived. The diffusion coefficient in the membrane increased slightly with the increase of the electrolyte concentration.