时间：2006年11月14日下午1：30－4：30
地点：环境系第一会议室
报告人和题目：

1、田路 幸和, Kazuyuki Tohji，教授
   Hydrogen Production using Sulfur Circulation in Water Disposal Plant

2、高桥 英志, Hideyuki Takahashi，博士
  Synthesis of the catalysts with high catalytic performance
       
3、佐藤 义伦, Yoshinori Sato，博士
  Influence of length on cytotoxicity of multi-walled carbon nanotubes

 Abstract:
1、Hydrogen Production using Sulfur Circulation in Water Disposal Plant
not available

2、Synthesis of the catalysts with high catalytic performance
The nanometer-sized materials have been vigorously investigated, particularly because of its application to industrial use, such as electronic devices. Many attempts to prepare the alloy and metallic nanoparticles by various methods have been reported1,2). However, “uniform” and “well-crystallized” alloy nanoparticles could not be synthesized by these methods. These results suggested that alloy nanoparticles with uniform and well- crystallized structure would be synthesized by controlling the growth mechanism in the liquid phase. Reduction rate of metals in the solution seriously depended on the condition of metal ion and/or metal complex in the solution. Thus, “uniform” alloy nanoparticles can be considered to synthesize from the only one reduction rate, in other words, from the only one metal complex in the solution.
In this study, the idea based on the predicted concentration of metal complexes in an aqueous solution as a function of pH will be introduced for the particle synthesis system.

3、Influence of length on cytotoxicity of multi-walled carbon nanotubes
Carbon nanotubes (CNTs) are single- or multi-cylindrical graphene structures that possess diameters of a few nanometers, while the length can be up to a few micrometers. These could have unusual toxicological properties, in that they share intermediate morphological characteristics of both fibers and nanoparticles. To date, no detailed study has been carried out to determine the effect of length on CNT cytotoxicity. In this paper, we investigated the activation of the human acute monocytic leukemia cell line THP-1 in vitro and the response in subcutaneous tissue in vivo to CNTs of different lengths. We used 220 nm and 825 nm-long CNT samples for testing, referred to as 220-CNTs and 825-CNTs, respectively. 220-CNTs and 825-CNTs induced human monocytes in vitro, although the activity was significantly lower than that of microbial lipopeptide and lipopolysaccharide, and no activity appeared following variation in the length of CNTs. On the other hand, the degree of inflammatory response in subcutaneous tissue in rats around the 220-CNTs was slight in comparison with that around the 825-CNTs. These results indicated that the degree of inflammation around 825-CNTs was stronger than that around 220-CNTs since macrophages could envelop 220-CNTs more readily than 825-CNTs. However, no severe inflammatory response such as necrosis, degeneration or neutrophil infiltration in vivo was observed around both CNTs examined throughout the experimental period.