Evaluation of the treatment performance of a multistage ozone/hydrogen peroxide process by decomposition by-products

The performance of a multistage ozone/hydrogen peroxide (O3/H2O2) process was evaluated with respect to total organic carbon (TOC) removal of waste waters. An aqueous humic acid solution (5.2 mgC l(-1) as TOC) and a sand filtered secondary sewerage effluent (5.6mgC l(-1) as TOC) were used as model waste waters. Appropriate range of hydrogen peroxide (H2O2) dose at each stage depended upon the components of the tested solutions that changed as the process proceeded. Higher hydrogen peroxide dose was required at later stages in which low reactivity compounds with hydroxyl radical (HO*), low molecular fatty acids, were predominant. And, oxalic acid concentration related to H2O2 demand at later stages. This was assumed that the slow decomposition of oxalic acid was rate-determining step for TOC removal after its accumulation. Also, it is important to maintain dissolved ozone at low concentration for efficient TOC removal because rapid ozone consumption is required for the rapid formation of hydroxyl radical (HO*).     

Selecting analytical target pesticides in monitoring: Sensitivity analysis and scoring

Measuring river water concentrations of all pesticides applied in a catchment area is a daunting task. This study aims to develop new score tables for selecting analytical target pesticides. Sensitivity analyses were conducted using a diffuse pollution hydrologic model to quantitatively evaluate the influence of pesticide properties (e.g., log K_OC, degradability [half-life]) on concentrations of rice-farming pesticides in river water. Using the results of the analyses, score tables were systematically designed for the pesticide properties such that the sum of the scores for a particular pesticide, designated as the contamination index, was proportional to the expected/predicted concentration of that pesticide in river water. The contamination indexes for pesticides applied in three river basins were calculated and compared with the corresponding observed pesticide concentrations. Correlations between contamination indexes and observed concentrations were fairly good. Pesticides were ranked according to the quotients obtained by dividing the pesticide concentrations predicted from the contamination indexes by the corresponding drinking-water quality guideline values, and pesticide candidates to be monitored were successfully selected on the basis of a threshold quotient.     

Neutron irradiation effects in uranium dicarbides

Changes of electrical resistivity and lattice parameter in UC_1.96 after neutron irradiation from $\text{9 × 10}{}^{14}$ to $\text{2 × 10}{}^{18}$ nvt were studied. The resistivity was increased with the dose up to $\text{1 × 10}{}^7$ nvt, and saturated at that dose. Above 10¹⁸ nvt a steep increase was observed. In the lattice-parameter changes, on the other hand, a gradual increase was observed in the dose range between $\text{2 × 10}{}^{16}$ and $\text{8 × 10}{}^{17}$ nvt; above that dose, an abrupt increase followed. Annealing experiments on the resistivity were performed up to 1000°C using the specimens irradiated to the low dose of $\text{5 × 10}{}^{16}$ nvt, and the increased resistivity was completely recovered in three steps. The activation energies of each step were estimated to be 0.3, 0.5 and $\text{1.6 ± 0.2}$ eV.     

Resistance in the Plant, <Emphasis Type=Italic>Barbarea vulgaris</Emphasis>, and Counter-Adaptations in Flea Beetles Mediated by Saponins

Three saponins and two sapogenins had differential effects on food consumption in five near-isogenic flea beetle lines, which differ in their ability to utilize a novel host plant, Barbarea vulgaris (Brassicaceae). The ability to live on this plant is controlled by major, dominant R-genes in the flea beetle, Phyllotreta nemorum (Coleoptera: Chrysomelidae: Alticinae). A susceptible genotype (rr) is unable to live on the plant, whereas resistant genotypes (RR and Rr) can utilize the novel host plant. Among compounds isolated from B. vulgaris, hederagenin cellobioside (hederagenin-3-O-(4-O-β-D-glucopyranosyl)-β-D-glucopyranoside) inhibited feeding, whereas the effect of oleanolic acid cellobioside was much weaker. The aglycones (sapogenins) were inactive. Although hederagenin cellobioside was active against all flea beetle lines, its effect on food consumption was much stronger on the susceptible genotype (rr) compared to the resistant genotype (Rr). Susceptible and resistant flea beetle genotypes were equally sensitive to a non-host saponin, α-hederin (hederagenin-3-O-(2-O-α-L-rhamnopyranosyl)-α-L-arabinopyranoside). These results suggest that R-alleles in flea beetles might be specific adaptations to defensive saponins in B. vulgaris. A possible mechanism of action of the R-alleles might be to encode for an enzyme (e.g. a glucosidase), which is able to cleave glycosidic bonds in hederagenin cellobioside, but not in α-hederin. The potential role of saponins as defensive compounds in B. vulgaris and as targets for counter-adaptations in flea beetles and other insects is discussed.     

Electronic behavior of calcined material obtained by microwave treatment of a tin-O-phenylene-O hybrid copolymer

Microwave treatment of a mixture of a tin-O-phenylene-O hybrid copolymer and graphite gave SnO₂-carbon cluster-Sn composite material. The resulting composite materials were characterized by using XRD, SEM, EDX and TEM. ESR spectral examinations of the calcined materials reveal the possibility of a photo-responsive electron transfer in the process of carbon clusters → SnO₂ and/or Sn. The calcined material was found to decompose 7,7,8,8-tetracyanoquinodimethane under light irradiation.     

Quasi-Drugs Developed in Japan for the Prevention or Treatment of Hyperpigmentary Disorders

Excess production of melanin or its abnormal distribution, or both, can cause irregular hyperpigmentation of the skin, leading to melasma and age spots. To date, various quasi-drugs that prevent or improve hyperpigmentary disorders have been developed and officially approved by the Ministry of Health, Labor and Welfare of Japan. Many of these inhibit the activity of tyrosinase, an enzyme required for melanin synthesis, for example, by competitive or non-competitive inhibition of its catalytic activity, by inhibiting its maturation, or by accelerating its degradation. In this review, we categorize the quasi-drugs developed in Japan to prevent or treat hyperpigmentary disorders, or both, and discuss perspectives for future development.     

Evaluation of feature values of surface electromyograms for user authentication on mobile devices

At the present time, mobile devices, such as tablet-type PCs and smart phones, have widely penetrated into our daily lives. Therefore, an authentication method that prevents shoulder surfing is needed. We are investigating a new user authentication method for mobile devices that use surface electromyogram (s-EMG) signals, not screen touching. The s-EMG signals, which are generated by the electrical activity of muscle fibers during contraction, are detected over the skin surface. Muscle movement can be differentiated by analyzing the s-EMG. In this paper, a method that uses a list of gestures as a password is proposed. And also, results of experiments are presented that was carried out to investigate the performance of the method extracting feature values from s-EMG signals (using the Fourier transform) adopted in this research. \(Myo^{TM}\), which is the candidate of s-EMG measurement device used in a prototype system for future substantiative experiments, was used in the experiment together with the s-EMG measuring device used in the previous research to investigate its performance.     

Chitin- polyurethane networks: correlations between physical properties and composition

Aiming to combine the bioproperties of chitin with the mechanical characteristics of polyurethane these two polymers were interconnected through a tridimensional network. The networks were formed from the addition reaction of the terminal isocyanate groups of a urethane prepolymer and the acetamide and hydroxyl groups of chitin. The crosslinking density was set from the ratio between the reacting groups, since the polyurethane length was kept constant (M_w = 66 kD, M_n = 48 kD). The biodegradability of polyurethane was afforded by the polycaprolactone segment of this component. The physical properties of the networks were analyzed in correlation with the composition, and compared with previous results obtained from blends with the same composition.     

Initial sintering mechanism and additive effect in zirconia ceramics

Y₂O₃-stabilized ZrO₂ (YSZ) ceramics have been used for various engineering applications because of their excellent mechanical properties or oxide-ion conductivity applicable to solid-electrolyte. The performance of YSZ depends on the sintered texture that is directly determined by sinterability of raw powders. A new kinetic analysis method of diffusion mechanism based on an initial sintering theory (grain-boundary or volume diffusion) is theoretically derived, the initial sintering mechanism of hydrolytic YSZ powder is experimentally determined, and the effects of powder characteristics on sinterability are discussed. Furthermore, the additive-enhanced sintering is proposed. A small amount of Al₂O₃ significantly enhances the densification. Using the additive effect, the low-temperature degradation that is the fault of zirconia ceramics can be improved by decreasing the sintering temperature.     

The relationship between solid-state fluorescence intensity and molecular packing of coumarin dyes

The solid-state fluorescence intensity of coumarin dyes depends on the substituents present at the 4- and 7-positions. 7-(Diethylamino)coumarins showed higher solid-state fluorescence quantum yield (Φ_f(ss) = 0.29–0.40) than 7-aminocoumarins (0.01). In the case of julolydyl coumarins, a 4-methyltetramethyljulolydyl derivative also displayed high Φ_f(ss) (0.34), this being greater than that observed for both 4-(perfluoroalkyl)tetramethyljulolydyl (0.09 and 0.10) and 4-methyljulolydyl derivatives (0.01). X-ray crystallographic analysis suggested that coumarin dyes bearing network hydrogen bonds and/or π–π stacking show weak solid-state fluorescence whereas coumarin dyes having isolated monomer- and dimer-type stacking show intense fluorescence. 4-(Perfluoroalkyl)tetramethyljulolydyl derivatives displayed medium fluorescence intensity owing to isolated monomer-type packing with little intermolecular interactions operating between adjacent molecules.