Journal of the Society of Powder Technology, Japan
Online ISSN : 1883-7239
Print ISSN : 0386-6157
ISSN-L : 0386-6157
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Volume 43, Issue 2
Displaying 1-9 of 9 articles from this issue
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  • Inhibitory Effects of Poly (aspartic acid-co-lactic acid) Nanospheres on Tumor Invasion through the Reconstituted Basement Membrane
    Hiroyuki Tsujimoto, Kaori Hara, Haruko Mimura, Nobuhiko Miwa
    2006 Volume 43 Issue 2 Pages 86-91
    Published: February 10, 2006
    Released on J-STAGE: April 30, 2010
    DOIhttps://doi.org/10.4164/sptj.43.86
    JOURNAL FREE ACCESS
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    As a skin safety in vitro test, the effects of poly (aspartic acid-co-lactic acid) encapsulated pro-vitamin nanospheres with the average diameter from 195 to 210nm on tumor invasion through the reconstituted basement membrane were evaluated with mouse melanoma cells B16BL6. The nanospheres containing pro-vitamin showed the inhibitory action against tumor invasion. However, the inhibitory effect on tumor-invasion was the highest for empty nanospheres without pro-vitamin and was enhanced with the increase in nanosphere concentration. This may be explained through the ionic interferences resulting from the anionic property of carboxyl group in aspartic acid. The poly-anions can interact or chelate with Zn ions of MMP intermediates instead of H2O molecules through a strong electrostatic force, suppressing the conversion of pro-MMP produced by the melanoma cells to activated MMP which lyses the basement membrane to form the tumor invasion routes. Therefore, the nanospheres are suggested to be safe material for skin application.
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  • Effect of Particle Size of Anode Catalyst for Direct Methanol Fuel Cell on Formation of Formic Acid and Formaldehyde
    Kazuhide Totsuka, Shogo Watanabe, Tadao Haraguchi
    2006 Volume 43 Issue 2 Pages 92-97
    Published: February 10, 2006
    Released on J-STAGE: April 30, 2010
    DOIhttps://doi.org/10.4164/sptj.43.92
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    The formation of byproducts such as formic acid and formaldehyde in direct methanol fuel cells (DMFC) with various anode catalysts is investigated through the quantitative analysis of the outflow fuel from anode using a high-performance liquid chromatograph and an ion chromatograph. The catalysts used are the alloy of platinum and ruthenium on carbon black. It is found that the byproducts are formed even when the fuel passes through the DMFC at open circuit voltage. The amount of byproducts is increased with the current density. Furthermore, the diameter of alloy particles is decreased from 6nm to 4nm by reducing the loading level from 54wt% to 33wt%. The use of finer alloy particles as the anode catalyst not only increases the power density of DMFC, but also suppresses the formation of formaldehyde at the anode.
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  • The Relationship between the Sintered Characteristics of Ultra-fine Hematite Particles and the Surface Smoothness of Non-magnetic Substrates for Magnetic Recording Media
    Kazuyuki Hayashi, Toshiyuki Toda, Keisuke Iwasaki, Seiji Ishitani
    2006 Volume 43 Issue 2 Pages 98-103
    Published: February 10, 2006
    Released on J-STAGE: April 30, 2010
    DOIhttps://doi.org/10.4164/sptj.43.98
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    Non-magnetic particles such as acicular hematite particles with finer size and higher dispersibility are required to produce multi-layered magnetic recording media with better performance. The specific surface area and primary particle size of non-magnetic acicular hematite particles were controlled by adjusting the heating conditions in the dehydration process. A sintering-parameter (SBET/STEM) was defined as the ratio of specific surface area measured by B. E. T. method to the specific surface area calculated from the particle size determined by TEM observation. The lower surface roughness of non-magnetic substrate is used to express the dispersibility of hematite particles. For 1.0≤SBET/STEM≤1.4, the dispersibility of hematite particles was much better in non-magnetic lacquer. When the optimum heating condition was applied to make hematite particles, the lower surface roughness was attained by using finer particles.
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  • Contact Charging of Particles
    Shuji Matsusaka, Hiroaki Masuda
    2006 Volume 43 Issue 2 Pages 104-114
    Published: February 10, 2006
    Released on J-STAGE: April 30, 2010
    DOIhttps://doi.org/10.4164/sptj.43.104
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    Contact charging is one of the fundamental phenomena in powder handling, and various applications based on this phenomenon have been developed. However, there are still many unsolved problems in the charging and the reported experimental results are inconsistent with one another. In the present review, the basic concepts of contact charging are summarized particularly focusing on the contact potential difference based on the work functions. Furthermore, the particle charging caused by repeated impacts is described theoretically. In addition, useful methods for measuring particle charge distribution and evaluating important electrostatic properties are introduced with the examples.
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  • Derivation of Mie Theory of Light Scattering
    Tatsushi Matsuyama
    2006 Volume 43 Issue 2 Pages 115-124
    Published: February 10, 2006
    Released on J-STAGE: April 30, 2010
    DOIhttps://doi.org/10.4164/sptj.43.115
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    The Mie's theory of light scattering by a small spherical particle was reviewed in details. It is a classic theory in which the light is treated as an electromagnetic wave, and the incident light activates oscillation of polarized charge in a sphere which results in a radiation of electromagnetic wave as the scattered light. The mathematical realization of the theory consists of some steps as: (1) vector wave equation is derived from Maxwell's equations, (2) general solution of the vector wave equation is obtained on spherical coordinates, (3) plane wave as incident light is expanded on the spherical coordinates, (4) scattered wave from the sphere satisfying the boundary conditions is obtained. Each step was explained in details in the review.
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  • Drying of Wet Materials in Fluidized Bed under Reduced Pressure
    Yuji Tatemoto
    2006 Volume 43 Issue 2 Pages 125-129
    Published: February 10, 2006
    Released on J-STAGE: April 30, 2010
    DOIhttps://doi.org/10.4164/sptj.43.125
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    High drying rate at a low temperature is an important issue for the drying of heat-sensitive materials. In order to achieve this goal, the combinations of fluidized bed drying with the superheated steam drying or the vacuum drying have been proposed. The present paper introduces the drying characteristics of wet materials in a superheated-steam fluidized bed dryer at a reduced pressure.
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  • Doctoral Thesis Introduction
    2006 Volume 43 Issue 2 Pages 135-136
    Published: February 10, 2006
    Released on J-STAGE: April 30, 2010
    DOIhttps://doi.org/10.4164/sptj.43.135
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  • Report of PAC RIM 6
    Tohru S. Suzuki
    2006 Volume 43 Issue 2 Pages 137-138
    Published: February 10, 2006
    Released on J-STAGE: April 30, 2010
    DOIhttps://doi.org/10.4164/sptj.43.137
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  • Activity Report of Chubu Branch
    Hiromitsu Yamamoto
    2006 Volume 43 Issue 2 Pages 140
    Published: February 10, 2006
    Released on J-STAGE: April 30, 2010
    DOIhttps://doi.org/10.4164/sptj.43.140
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