Support effect of anode catalysts using an organic metal complex for fuel cells

The carbon support effect of Pt–Ni(mqph) electrocatalysts on the performance of CO tolerant anode catalysts for polymer electrolyte fuel cells (PEFCs) was investigated using carbon black and multi-walled carbon nanotubes (MWCNTs), with and without defect preparation. 20%Pt–Ni(mqph)/defect-free CNTs showed a very high CO tolerance (75% compared to the CO-free H₂ case) under 100 ppm CO level in the half-cell system of the hydrogen oxidation reaction. On the other hand, the hydrogen oxidation current on Pt–Ni(mqph)/defective CNTs, Pt–Ni(mqph)/VulcanXC-72R and Pt–Ru/VulcanXC-72R significantly decreased with increasing concentration of CO up to 100 ppm (25–47% compared to the CO-free H₂ case). It is thus considered that the carbon support materials strongly affect the CO tolerance of anode catalysts. This is ascribed to a change in the electronic structure of the Pt particles due to the interaction with the graphene surface, leading to a reduction in the adsorption energy of CO. Ni(mqph) also mitigates CO poisoning due to its ability of CO coordination on Ni metal center.     

Pace-sync shoes: intuitive walking-pace guidance based on cyclic vibro-tactile stimulation for the foot

We propose a walking guidance method with a sandal-shaped vibration interface and describe two experiments we performed to formulate the design principles of the interface. In the interface, a vibrating motor presents timing information to the foot, and pressure sensors measure walking pace. Our method is a combination of the walking-state monitoring and vibro-tactile feedback to maintain or promote a walking pace. Vibration stimuli with a constant presentation interval are alternately and repeatedly given to the right or left foot of the user according to the measured walking pace, and then the walking pace gradually conforms to the presented interval of the vibration. In the experiments, we specified the effective timing and intervals of the vibration stimuli for efficient inductance of walking pace. The method is applicable for training and coaching in sports and rehabilitation in health care.     

Dose-response relationship between total cadmium intake and metallothioneinuria using logistic regression analysis

The dose-response relationship for environmental cadmium exposure was assessed using logistic regression analysis. The prevalence of metallothioneinuria was employed as a response variable, while age and total cadmium intake, calculated from the average cadmium concentration in rice and duration of residence in the cadmium-polluted area, were used as explanatory variables. The target population comprised of 1843 cadmium-exposed and 240 non-exposed inhabitants of Ishikawa, Japan. The individuals were divided into 96 subgroups by sex, age (4 categories), cadmium concentrations in rice (3 categories) and length of residence in the polluted area (4 categories). Only total cadmium intake had a significant association with the prevalence of metallothioneinuria. In the non-exposed subjects total cadmium intakes corresponding to 2.5% prevalence of metallothioneinuria were calculated. Based on metallothionein levels expressed as either microgram/l urine or microgram/g creatinine, the total intakes were: 2.221 or 2.207 g in men and 2.365 or 0.319 g in women, respectively. Most of these values were similar to those reported by us previously, employing simple regression analysis. It is concluded, therefore, that a maximum allowable intake of about 2 g cadmium is a reasonable estimate for preventing the cadmium-induced renal dysfunction.     

Optically active alternating copolymer and Diels-Alder adduct

Summary Asymmetric induction copolymerization and Diels-Alder reaction were investigated between acrylic monomer and olefin or diolefin with use of an optically active aluminum compound as the complexing agent. In the copolymerization, only benzofuran gave an optically active alternating copolymer, while butadiene and indene gave alternating copolymers but with no optical activity. EtAlCl₂-l-menthol was the most effective complexing agent. However, EtAlCl₂-d-neomenthol was ineffective.On the other hand, Diels-Alder reaction was in general more easily stereocontrolled. For instance, both complexing agents were effective for the synthesis of optically active Diels-Alder adducts with butadiene or cyclopentadiene, perhaps due to the rigid cyclic structure in a transition state of the reaction.     

Tests of a silica aerogel Cherenkov counter

A Cherenkov counter with silica aerogel of refractive index 1.06 as radiator has been constructed and tested. The Cherenkov light produced in 9 cm thick silica aerogel was detected with four 5″-photomultipliers through a 162 cm long air light guide. The photoelectron yield for a 1 GeV/c pion beam was found to be 6 and uniform over a sensitive area of 40 × 30 cm².     

Thermotropic cellulose derivatives with flexible substituents

Summary Three kinds of fully substituted cellulose derivatives, cellulose triheptanoate (CTH), tri-O-heptyl cellulose (THC) and tri-O-2-butoxyethyl cellulose (TBC) were prepared. These polymers, having a side chain of similar length but of differing chemical structure, were found to show significantly different therraotropic behavior: TBC forms a cholesteric liquid crystalline phase at temperatures between 50 °C and 165 °C, the cholesteric pitch covering the region of visible lights. THC also displays a cholestric structure at temperatures between 80 °C and 130 °C with pitches on the order of several micrometers. CTH appears to show liquid crystallinity only in a very limited temperature range around 100 °C.     

Anodic oxidation of diphenyldiselenide in acetonitrile

The electrochemical behaviour of diphenyldiselenide in acetonitrile solution was studied by several electrochemical techniques. Controlled potential electrolysis in the presence of cyclohexene was also studied. The cyclic sweep voltammogram exhibited two irreversible anodic peaks at 1.35 and 1.65 V and one cathodic peak at ?1.25 V. It was concluded that the primary step is one-electron removal from the substrate, and the SeSe bond cleavage follows to generate phenylselenium cation and phenylselenium radical, of which the former species can react with cyclohexene to give mainly 2-acetamido-1-phenylseleno-cyclohexane. The possibility of utilizing phenylselenenic acid as the current mediator in the allylic hydroxylation reaction seems very limited. The cathodic reaction of diphenyldiselenide was also discussed briefly.