Thermal diffusivity anisotropy measured by a temperature wave method in the homologous series of (p-alkoxybenzylidene)-p'-octylaniline (nO.8).

The anisotropy of thermal diffusivity in four homologues of (p-alkoxybenzylidene)-p'-octylaniline (nO.8, n = 4 - 7) was measured using a temperature wave method. The results show that the thermal diffusivity component along the director (α(∥)) is considerably larger than that perpendicular to the director (α(⊥)) in all mesophases, i.e., nematic (N), smectic A (SmA), smectic B (SmB), and smectic G (SmG) phases. Both components of the thermal diffusivity show a dip at the second- or weakly first-order N-SmA phase transition due to the heat capacity anomaly. In contrast, at the first-order SmA-SmB phase transition, thermal diffusivity exhibits a stepwise increase. The x-ray and calorimetric measurements enable a calculation of the thermal conductivity and the study of the effect of the molecular length on the thermal conductivity and diffusivity in the SmA and SmB phases. For the homologues n = 4, 5, and 6, which exhibit the same phase sequence upon cooling, the parallel component of the thermal conductivity k(∥) in the SmA and SmB phases systematically increases with increasing length of the molecular tails, while no such increase is observed in the thermal diffusivity α(∥). We thus conclude that the molecular model [Urbach et al., J. Chem. Phys. 78, 5113 (1983)] is valid for the qualitative prediction of the effect of the molecular length on the magnitude of the thermal conductivity.

Features of the Vision of Elderly Pedestrians when Crossing a Road.

The present study clarifies the mechanism by which an accident occurs when an elderly pedestrian crosses a road in front of a car, focusing on features of the central and peripheral vision of elderly pedestrians who are judging when it is safe to cross the road. For the pedestrian's central visual field, we investigated the effect of age on the timing judgment using an actual car. The results for daytime conditions indicate that the elderly pedestrians tended to make later judgments of when they crossed the road from the right side of the driver's view at high car velocities. At night, for a car with its headlights on high beam, the average car-pedestrian distances of elderly pedestrians on the left side of the driver's view were significantly longer than those of young pedestrians at velocities of 20 and 40 km/h. The eyesight of the elderly pedestrians during the day did not affect the timing judgment of crossing a road. At night, for a car with its headlights on either high or low beam, the average car-pedestrian distances of elderly pedestrians having good eyesight were longer than those of elderly pedestrians having poor eyesight, for all car velocities. The color of the car body in the central visual field did not affect the timing judgment of elderly pedestrians crossing the road. Meanwhile, the car-body color in the elderly pedestrian's peripheral vision strongly affected the pedestrian's awareness of the car.

Pretransitional layer contraction at the chiral smectic A-to-chiral smectic C phase transition of a chiral nitroxide radical.

We have designed and synthesized a new chiral paramagnetic liquid crystalline compound with a nitroxide radical moiety showing chiral smectic A (SmA*) and C (SmC*) phases. This compound shows pretransitional layer contraction prior to the SmA*-to-SmC* phase transition in the cooling run. Electron paramagnetic resonance spectroscopy, X-ray diffraction analysis, and polarized optical microscopy reveal that a temperature-dependent conformational change is responsible for the pretransitional layer contraction.

Optical resolution of 5-alkyl-delta-valerolactones and synthesis of optically active 5-fluoroalkanols.

Optical resolutions of 5-alkyl-delta-valerolactones were carried out by derivatization to the diastereomeric amides, in which (R)-(+)-1-(1-naphthyl)ethylamine or (S)-(-)-1-phenylethylamine were used as resolving agents. Optically active 5-fluoroalkanols, useful intermediates for fluorinated ferroelectric liquid crystals, were derived from the resolved lactones in four steps without racemization.

Allergies correlated to adverse reactions induced by non-ionic monomeric and ionic dimeric contrast media for contrast enhanced CT examination.

Although contrast media are indispensable for x-ray diagnosis, they are xenobiotics and may cause undesirable adverse reactions. We have correlated several allergies to the adverse reactions caused by three representative contrast media in order to predict and prevent possible problems. The adverse reactions were observed at probabilities of up to 100%(odds ratio 8.0) in drug allergy and contact dermatitis patients. These allergies were proven in this study to be type IV reactions, and all the observed adverse reactions were classified as allergies of either type I or IV. Thus, one can predict to some extent even the time when the adverse reaction will appear after the injection of contrast medium. Finally, a questionnaire to be administered prior to contrast enhanced CT examinations has been proposed. The questionnaire is designed to predict adverse reactions on the basis of statistical analysis. Since the physicochemical properties of contrast media are different, this questionnaire is also useful for selecting the most suitable contrast medium for the patient.