Carbon-14 labelled sucrose transportation in an Arabidopsis thaliana using an imaging plate and real time imaging system

As an approach to increased production of rape seed oil from Brassica napus L., Arabidopsis thaliana, a species from the same Brassicaceae family, was used to investigate transport behavior and distribution of matter in the plant body. In this study, sucrose, an initial metabolic product of photosynthesis, labeled with carbon-14 was used. The sucrose was applied to A. thaliana via the surface of a rosette leaf. Using the real time radioisotope imaging system we developed and an imaging plate (IP), images of whole or part of the sample were obtained. The sucrose assimilation products were accumulated in maturing tissue such as flowers and fruits, and in a joint part. From the comparison among branches and stems, it was indicated that there were different patterns of demand and distribution of sucrose assimilation products depending on the tissue and its growing stage. This might be caused by either morphological reason such as diameter and location of the sieve tube, or genetic factors such as an activity of a membrane transport protein. Because of self-absorption of carpels, it was difficult to observe the accumulation of carbon-14 in the seeds inside the fruits; however, an IP image of a frozen section of a fruit revealed that carbon-14 transport to seeds was higher than that of carpels. These methods will help us gain insight into matter transport and strategies to improve the production of rape seed oil.     

Al behavior in tobacco cells by NAA and staining method

In the study of aluminum toxicity for plant, it is important to analyzethe behavior of Al in cells. We present how Al is taken up by tobacco cellsthrough lumogallion staining method developed by our laboratory. The fluorescenceintensity from the cell was increased rapidly between 4 and 8 hours of 1 mMAl treatment. To calibrate the fluorescence intensity from Al-lumogallioncomplex, Al amount in the cell was determined by NAA. When the same samplewas analyzed by ICP-AES, Al amounts in all the samples were 13% lower thanthose measured by NAA.     

Amino acid adsorption on single-walled carbon nanotubes

We investigate and discuss the adsorption of a few amino acids on (3,3) carbon nanotubes and on graphite sheets through calculations within density functional theory. Results show weak binding of the biomolecules on both substrates, but through generally favourable adsorption pathways. Zwitterion adsorption through the charged amine and carboxylate groups are bound stronger to the nanotube surface in comparison to their nonionic counterparts, as well as on histidine, phenylalanine, and cysteine side chain groups fixed in specific orientations. Binding strengths on graphite suggest dissimilar trends for amino acid interactions with increasing nanotube diameter.     

Formation of iron fine particles in a crystal lattice by the computer simulation

The growing up of the fine particles in a sapphire crystal was simulated with a computer and the expected Mössbauer spectra were calculated by considering the influence of the nearest neighbors and next-nearest neighbors to the magnetic hyperfine field of the iron atoms. The simulated spectra were compared with the Mössbauer spectra observed with a Fe-implanted sapphire and the agreement between them was satisfactory on the whole. It is also revealed that an iron atom implanted into a sapphire crystal may interact, before coming to rest, with the iron fine particles situated within 2–3 nm in the crystal.     

Response of Ferroelectric Molecules in Liquid Crystal Display under an Applied Electric Field

The dynamic changes of ferroelectric liquid crystal (FLC) molecular alignments under the applied electric field were examined by observing the formation of conoscopic figures with a time resolution of 0.1 ms, which reflect the temporal and spatial dependences of the LC molecular alignments on the azimuthal angle. By a detailed comparison of the experimental conoscopic figures with simulated figures, the molecules began to shift from the central portion of the helix to the outer ends within 0.1 ms following application of the electric field. The positions of molecular layers having the fastest moving velocity (Δφ/Δt) corresponded to the positions with the azimuthal angles of π/2 and 3π/2rad.     

Preparation of nano-sized functional materials using laser ablation in liquids

We propose a convenient technique applicable for investigations of various functions of nanoparticles produced by laser ablation in liquids. It was demonstrated that nanoparticles of anatase-TiO₂, a electrode material for lithium secondary batteries, produced by laser ablation in acetone could be efficiently deposited on a substrate by using an electrophoresis technique. Analysis of the electrochemical properties of nanoparticles become much more facile with those deposited nanoparticles than with dispersed nanoparticles. In addition, it was demonstrated that comparison of the electrochemical properties between nanoparticles and microparticles were possible by means of this technique.     

Theoretical studies on magnetic interactions between Cu(II) ions in salen nucleobases

The magnetic and other physical properties between Cu²⁺ ions coordinated by salen–base pairs (Cu²⁺–DNA) are examined by using DFT calculations. In order to consider effects of entanglement and dis-entanglement of the double helix chain, three types of structural disorders i.e. distance, rotation angle and discrepancy in XY-plane, are changed in the model dimer structure. All calculated results show that J_ab values are weak anti-ferromagnetic couplings. It is also found that the J_ab values strongly depend on the salen structure.