Plant zygote cells exhibit tip growth, producing a hemisphere-like tip. To understand how this hemisphere-like tip shape is formed, we revisited a viscoelastic–plastic deformation model that enabled us to simultaneously evaluate the shape, stress and strain of Arabidopsis (Arabidopsis thaliana) zygote cells undergoing tip growth. Altering the spatial distribution of cell wall extensibility revealed that cosine-type distribution and growth in a normal direction to the surface create a stable hemisphere-like tip shape. Assuming these as constraints for cell elongation, we determined the best-fitting parameters for turgor pressure and wall extensibility to computationally reconstruct an elongating zygote that retained its hemisphere-like shape using only cell contour data, leading to the formulation of non-dimensional growth parameters. Our computational results demonstrate the different morphologies in elongating zygotes through effective non-dimensional parameters.

The purpose of this study was to examine whether vehicle type based on size (car vs. other = truck/van/SUV) had an impact on the speeding, acceleration, and braking patterns of older male and female drivers (70 years and older) from a Canadian longitudinal study. The primary hypothesis was that older adults driving larger vehicles (e.g., trucks, SUVs, or vans) would be more likely to speed than those driving cars. Participants (n = 493) had a device installed in their vehicles that recorded their everyday driving. The findings suggest that the type of vehicle driven had little or no impact on per cent of time speeding or on the braking and accelerating patterns of older drivers. Given that the propensity for exceeding the speed limit was high among these older drivers, regardless of vehicle type, future research should examine what effect this behaviour has on older-driver road safety.

A nanoparticle catalyst of PtRuAu/C was synthesized by including an Au precursor in the radiolytic process for preparing a PtRu/C catalyst. Their methanol oxidation activity and electrochemical durability were measured by linear sweep voltammetry before and after potential cycling treatment. PtRuAu/C had a significantly higher durability than PtRu/C while maintaining a comparable high activity. The morphology and substructure of the nanoparticles were investigated by energy-dispersive x-ray spectroscopy, x-ray diffraction, and x-ray absorption fine structure spectroscopy. Metallic nanoparticles with diameters of about 2 nm were obtained; they probably had Pt-core/PtRu-shell structures. Transmission electron microscopy observations after potential cycling revealed that 2-nm-diameter nanoparticles containing Au did not coarsen, whereas nanoparticles without Au coarsened significantly to 3.7 nm. Some crystal defaults were observed in the coarsened particles, implying that the coarsening was caused by Ostwald ripening. The Au addition to catalyst particles consisting of PtRu inhibits coarsening and consequently improves the electrochemical durability.

Nanoparticle catalyst of PtRuAu/C for direct methanol fuel cell anodes was synthesized by a radiolytic process. Its methanol oxidation activity and the electrochemical durability were evaluated by using the linear sweep voltammetry and the cyclic voltammety. The Au addition significantly improved the durability in comparison with PtRu/C catalyst without losing its high activity. The atomic structure was characterized with techniques of the transmission electron microscopy, the X-ray diffraction, the X-ray fluorescence spectroscopy and the X-ray absorption fine structure. These results implied that the arrangement of Pt and Ru atoms in the PtRuAu/C has no significant difference from that without Au, possessing a structure of Pt rich core and PtRu alloy shell. We concluded that the improvement in durability could originate from these PtRu nanoparticles decorated with Au, but not from particles with high Au contents.

The static second hyperpolarizabilities (γ) of open-shell organic nonlinear optical (NLO) systems composed of singlet diradical molecules are investigated using ab initio molecular orbital (MO) and density functional theory (DFT) methods. It is found that neutral singlet diradical systems with intermediate diradical characters tend to enhance γ as compared to those with small and large diradical characters. This suggests that the diradical character is a novel control parameter of γ for singlet diradical systems.