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1

Molecular theoretic study of Freedericksz transition : symmetry breaking of oblique axial order

Kio M., Torikai M., Yamashita M.

Opto-Electronics Review

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2009

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Vol. 17, No. 1

8-15

EN

Freedericksz transition, which is usually analyzed by an elastic theory, is studied on the basis of statistical mechanical ground, where nematics with positive dielectric anisotropy in homogeneous anchoring cell is exposed to an electric field in the direction of wall normal. In low temperature region, an oblique axial symmetry breaking occurs, which is nothing but the Freedericksz transition. In high temperature and high field region, biaxial nematic phase with principal axis parallel to the field direction at interior area of the system is proved to appear. A phase diagram on the field versus temperature plane is obtained and compared with the one at a bulk with common biaxial symmetry, where both of electric and magnetic fields are applied in directions perpendicular to each other. In the latter, no symmetry breaking occurs, in contrast with the former case above-mentioned, and the reason why this difference occurs is elucidated.

2

Effects of fields and anchoring on biaxial nematic ordering

Yasen M., Torikai M., Yamashita M.

Opto-Electronics Review

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2009

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Vol. 17, No. 2

89-94

EN

Symmetry of a nematic liquid crystal phase is broken by an anchoring wall and also by an external field. Nematic system sandwiched between biaxial anchoring walls is introduced as a correspondent to a bulk nematic system exposed to a couple of fields, an electric field and a magnetic one in directions perpendicular to each other, and thermal behaviours of the system are studied. The crossover between a homeotropic structure and homogeneous one occurs, similarly to the bulk system in the fields, in which the anchoring condition of coexistence is shown to have the same expression as the one at the bulk. As to a characteristic phenomenon at the sandwiched system, it is proved that an appearance of a biaxial nematic order suppresses a uniaxial nematic order. A surface transition, i.e., a wetting phenomenon is shown to occur also in the biaxial nematics, even though the uniaxial order is suppressed therein.

3

Synthesis and evaluation of novel mri contrast agents of chemically modified GD-DTPA complexes with sugars

Sugiyama M., Yamashita M., Yu G., Fujie M., Ogawa K., Ozaki N., Aoki T., Mizuno S., Okada S., Tachi K., Aoshima K., Sankar U. R., Kumar B. S., Takehara Y., Sakahara H.

Journal of Automation Mobile Robotics and Intelligent Systems

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2009

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Vol. 3, No. 4

191-194

EN

MRI is one of medical diagnostic imaging technologies that can draw the cross section in the body. To obtain a clearer image, Gd complexes are often used as MRI contrast agents. Gd-DTPA (Gd-Diethylenetriaminepentaacetate, Magnevist registered trademark ) is used in particular as the MRI contrast agents. We prepared and evaluated novel MRI contrast agents that were chemically modified Gd-DTPA with sugars (represented as Gd-DTPA-Sugar) via hydrolysis route for providing specificity to target organs and tissues. Gd-DTPASugar complex showed an excellent potential for the MRI contrast agent (r1=31.2 s-1mM-1). Gd-DTPA-Sugar complexes alternatively prepared by shorter synthetic route without protection/ deprotection (hydrolysis) method showed inferior results (r1=6.3 and 8.1 s-1mM-1) to the hydlized product.

4

R&D of novel medicinal materials for curing cancer: sugar modified Gd-DTPA MRI contrast agents and phospha sugar anti-cancer agents

Yamashita Y., Yamashita M., Fujie M., Suyama K. A. T., Ito S., Reddy V. K., Yamada M., Ogawa K., Ozaki N., Nakamura S., Aoki T., Yu G., Aoshima K., Kato T., Kamikage N., Kiyofuji K., Takehara Y., Sakahara H., Takayanagi H., Oshikawa T., Laurent S., Burtea C., Van der Elst L., Muller R. N.

Journal of Automation Mobile Robotics and Intelligent Systems

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2009

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Vol. 3, No. 4

80-83

EN

Novel Sugar Dendritic Gd-DTPA Complexes for MRI Contrast Agents were prepared and evaluated by in vitro and in vivo methods. The sugar dendritic MRI contrast agents have a good blood vesse pool character, and draw blood vessels and liver cancer remarkably clearer than the clinically using Gd-DTPA. Phospha sugar derivatives or phosphorus heterocyclic derivatives provided by functional groups such as epoxide, bromide, etc., were prepared and evaluated by MTT in vitro method. These phospha sugar derivatives showed excellent activities against leukemia cells as well as solid cancer cells in fashions of (i) higher activity, (ii) wider spectra, (iii) higher selectivity and specificity distingushing healthy and cancer cells, etc., compared with the molecular targeting chemotheraputic anti-cancer agent, Gleevec.

5

Niektóre zagadnienia korozji atmosferycznej badane za pomocą sondy Kevina

Oriani R. A., Yamashita M., Nagano H.

Ochrona przed Korozją

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1998

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nr 10

281-286

PL

Opisano w skrócie działanie sondy Kelvina, wykazując celowość użycia na elekrodę Kelvina materiału niewrażliwego na środowisko. Podano przykłady zastosowania tego przyrządu, między innymi do wyznaczania charakterystyk elektrochemicznych korozji metali pod bardzo cienkimi warstewkami roztworów elektrolitów. Zastosowania te obejmują pomiar korozji galwanicznej, potencjału korozyjnego i szybkości korozji w funkcji grubości warstewki roztworu, określenie korozji wywołanej jonizujacymi się cząstkami w wilgotnych gazach oraz potencjału korozyjnego różnych stali w zależności od liczby cykli wilgotnych i suchych.

EN

After a brief description of the operation of the Kelvin probe, the use of envirinment-insensitive material as the Kelvin electrode is discussed. Various examples of the application of this instument are described in wchih some of the important characteristics of corrosion under extremely thin layers of electrolytic solutions are brought out. These applications include galvanic corrosion, corrosion potential, and corrosion rate as functions of solution layer thickness, corrosion by ionizable particles under humid gases, and corrosion potential of various steels as a function of the number of wet/dry cycles.