Preparation of functional polymer-microspheres by suspension copolymerization of ethylene glycol dimethacrylate with hydrophilic monomers

A study was made of suspension copolymerization of ethylene glycol dimethacrylate (EDMA) with some hydrophilic monomers (M₂) to prepare gel particles having a large number and various kind of functional groups on their surface. Delayed charge of M₂ to partially prepolymerized EDMA suspension resulted in the formation of favorable particles. The polymerization leveled off despite an appreciable amount of remaining M₂ in the aqueous phase, and the amount of copolymerized M₂ and the fraction of on-surface M₂ units depended significantly on the kind of M₂ as well as the mode of M₂ charge. These dependences were explained in terms of the partition coefficient of M₂ between EDMA and water and the monomer reactivity ratio.     

Synthesis and properties of Ba3NaRu2O9−δ and Ba3(Na, R)Ru2O9−δ (R=rare earth) crystals

Crystals of Ba₃NaRu₂O_9−δ (δ≈0.5) and Ba₃(Na, R)Ru₂O_9−δ (R=Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm and Yb) were grown by an electrochemical method, and their crystallographic, magnetic, and electric properties were studied. All crystals have a hexagonal structure of space group P6₃mmc. Ba₃NaRu₂O_9−δ and Ba₃(Na, R)Ru₂O_9−δ (except Ce) have a negative asymptotic Curie temperature suggesting the existence of an antiferromagnetic order; however, they are paramagnetic at temperatures above 1.7 K. Ba₃NaRu₂O_9−δ has an effective magnetic moment P_eff of 0.91 μ_B, while P_eff of Ba₃(Na, R)Ru₂O_9−δ (except Ce) reflects the large free-ion moment of the rare earth ions. Ba₃(Na, Ce)Ru₂O_9−δ shows peculiar magnetic behavior that differs from the magnetism of other Ba₃(Na, R)Ru₂O_9−δ crystals. The resistivity of all crystals exhibits an activation-type temperature dependence with an activation energy in the range of 0.10.2 eV.     

Levee damage and revetment erosion by the 2019 Typhoon Hagibis in the Chikuma River,Japan

Due to Typhoon Hagibis (Typhoon No. 19) in October 2019, also known as the Reiwa 1 East Japan Typhoon, many parts of the Chikuma River’s levee in Nagano Prefecture were damaged. There were instances of levee collapse due to overtopping, and an electric railway bridge also collapsed when an eroded revetment broke. In the present study, these disasters were investigated.The investigation considered both the geology - geomechanics and the hydraulics of the levee collapse due to overtopping. The results suggest that the most significant factor in the collapse of the levee was structural weakness. There were cases in which the tenacity of a levee was improved by taking simple measures against seepage. It was found that the bridge abutments washed away mainly because the river levee became a water-colliding front due to changes in the water route following the erosion of a sandbar in the process of river level decline after the peak.     

Salmonella prevalence and total microbial and spore populations in spices imported to Japan

A total of 259 samples of 40 types of spices were tested for Salmonella prevalence and total microbial and spore populations. Salmonella enterica serotypes Weltevreden and Senftenberg were isolated from a black- and red-pepper sample, respectively. Because Salmonella was not detected by the most-probable-number method, it indicated that at least one cell of the microorganism was present in 25 g of sample. The mean aerobic bacterial count was greater than 5.39 log CFU/g in turmeric, garam masala, curry powder, and paprika. The mean bacterial spore counts were greater than 4.33 log CFU/g in turmeric and curry powder. The mean aerobic bacterial count in the two Salmonella-isolated samples was 6.93 log CFU/g. These results indicate that spices can be a source of contamination in the products where they are used as ingredients, and methods to reduce the microbial load in spices should be used.     

Effect of benzotriazole (BTA) addition on Polypyrrole film formation on copper and its corrosion protection

Benzotriazole (BTA) was added in a conducting Polypyrrole (PPy) film prepared on copper in oxalic acid aqueous solution containing pyrrole monomer to improve corrosion protection by the PPy film and reduce copper corrosion. When BTA was added in the preparation solution, the copper surface was covered by a BTA–Cu complex layer before the anodic polymerization of PPy was started. On the copper surface with the BTA layer, the initial dissolution of copper was inhibited and the PPy polymerization-deposition was started immediately after the anodic current was imposed. The PPy film thus formed was doped with oxalic ions and ionized BTA and was homogeneous in thickness and strongly adhesive. The PPy film containing BTA protected the copper from corrosion in 3.5 wt.% NaCl solution. In 400 h of immersion, copper dissolution was inhibited with 80% protection efficiency relative to that of bare copper.     

Aligning vapor-grown carbon fibers in polydimethylsiloxane using dc electric or magnetic field

A trace amount of vapor-grown carbon fibers (VGCFs), which, as received, had an aggregated lump form, was completely dispersed in polydimethylsiloxane, a nonpolar viscous liquid, at room temperature by mechanical stirring. Using this uniformly dispersed sample as a starting material, a dc electric or magnetic field was applied to induce the formation of an aligned structure. In situ transmission optical microscopy was carried out to observe the structural development of VGCFs in polydimethylsiloxane under the dc electric or magnetic field, which was applied both parallel and perpendicular to the observation direction. Upon application of a dc electric field, an aligned ramified network structure of VGCFs developed between the electrodes. In the formation of the network structure, ends of VGCFs became connected to ends of other VGCFs, which was followed by rotation and orientation of the VCGFs. On the other hand, upon application of a magnetic field, the VGCFs were only rotated, without the formation of a network. The electric resistivity of the network structure was evaluated. Additionally, the influence of the viscosity of the polydimethylsiloxane matrix on the structural formation process was examined.     

Enantiomeric composition of ipsdienol: A chemotaxonomic character for north American populations ofIps spp. in thepini subgeneric group (coleoptera: Scolytidae)

Thirty-five populations ofIps pini (Say) and one population each ofIps avulsus (Eichhoff) andIps bonanseai (Hopkins) were analyzed for the enantiomeric composition of ipsdienol (2-methyl-6-methylene-2,7-octadien-4-ol). Populations ofI. pini occur as at least two distinct regional pheromone variants: New York type [32%-(–) to 56%-(–)-ipsdienol] and California type [94%-(–) to 98%-(–)-ipsdienol]. A third phenotype may occur in southeastern British Columbia, Idaho, and Montana [91%-(–) to 95%-(–)], possibly indicating a zone of hybridization. Populations of the New York type occur in southwestern British Columbia, Alberta, Saskatchewan, Minnesota, and Wisconsin suggesting a continuum through the Canadian provinces and Lake States. The presence of the New York type in western Canada is likely linked to the Quaternary history of the transcontinentally distributed host,Pinus banksiana Lamb. MaleI. avulsus [25%-(–)] and maleI. bonanseai [–29%-(–)] both produce ipsdienol, but not ipsenol. Production of ipsdienol by maleI. pini was evaluated in six differentPinus spp. hosts. Following transfer of maleI. pini to hosts other than the host of origin, the percentage of the (–)-enantiomer of ipsdienol declined when compared to production in the host of origin.     

Conversion of the guanine nucleotide binding sites of ras protein resulting in the reduction of base specificity

A gene coding for the novel ras protein, p21^x, in which thedomains of guanine binding and phosphate binding were exchanged,was constructed and expressed in Escherichia coli. The geneproduct, p21^x, showed GTP binding activity, but no GPTase activity.In addition, p21^x revealed binding activity toward ATP and CTP.In a competitive binding assay, [³H]GTP binding to p21^x wasinhibited in the presence of ATP, CTP and UTP, ITP as well asGDP, GTP and dGTP.     

Structural and magnetic characterization of martensitic Ni–Mn–Ga thin films deposited on Mo foil

Three martensitic Ni_51.4Mn_28.3Ga_20.3 thin films sputter-deposited on a Mo foil were investigated with regard to their crystal and magnetic domain structures, as well as their magnetic and magnetostrain properties. The film thicknesses, d, were 0.1, 0.4 and 1.0μm. X-ray and electron diffraction patterns revealed a tetragonal modulated martensitic phase (10 M) in the films. The surface topography and micromagnetic structure were studied by scanning probe microscopy. A maze magnetic domain structure featuring a large out-of-plane magnetization component was found in all films. The domain width, δ, depends on the film thickness as . The thickness dependencies of the saturation magnetization, saturation magnetic field and magnetic anisotropy were clarified. Beam cantilever tests on the Ni–Mn–Ga/Mo composite as a function of magnetic field showed reversible strains, which are larger than ordinary magnetostriction.     

An experimental study on ejection forces of injection molding

In injection molding, the ejection forces decrease when the surface roughness of mold decreases. However, the ejection forces increase contrary in the area of surface roughness is less than 0.2 μmRa. Several kinds of PVD films are coated on the mold cores to prevent the increasing of ejection forces. Some of these PVD films showed effective prevention of increasing of ejection forces.