Browsing by Author "Huang, Shu-Ping"

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Characterizations of UV-Curable Montmorillonite/Epoxy Nanocomposites Prepared by a Hybrid of Chemical Dispersion and Planetary Mechanical Milling Process
(2012-03-15)
Huang, Heh-Chang
;
Huang, Shu-Ping
;
Hsieh, Tsung-Eong
;
Chen, Chin-Hsin
;
材料科學與工程學系
Ammonium salt, [2-(methacyloyloxy)ethyl] trimethylammonium methyl sulfate (MAOTMA), was adopted to modify montmorillonite (MMT) via the cationic exchange process in an acidic environment and a successful enlargement of MMT lamellar spacing from 1.18 to 1.39 nm was identified by x-ray diffraction and Fourier-transform infrared spectroscopy. Accordingly, UV-curable epoxy nanocomposite resins containing various amounts of MAOTMA-modified MMT were prepared with the aid of a planetary mechanical milling process. Transmission electron microscopy revealed a uniform dispersion of exfoliated MMT lamella in epoxy matrix, leading to the distinct improvements on thermal stability and thermal expansion property of nanocomposite samples. Calcium (Ca) test indicated that the good dispersion of MMT fillers in polymer effectively suppresses the moisture permeation in sample matrix. More than twofold increment on retention time of 5% Ca hydrolysis and 20% improvement on the permeation kinetic parameters were observed in the nanocomposite sample containing 8 wt % MMT in comparison with the pristine epoxy sample. (C) 2011 Wiley Periodicals, Inc. J Appl Polym Sci 123: 3199-3207, 2012
Genetic Requirements for Klebsiella pneumoniae-Induced Liver Abscess in an Oral Infection Model
(2009-07-01)
Tu, Ya-Chun
;
Lu, Min-Chi
;
Chiang, Ming-Ko
;
Huang, Shu-Ping
;
Peng, Hwei-Ling
Klebsiella pneumoniae is the predominant pathogen of primary liver abscess. However, our knowledge regarding the molecular basis of how K. pneumoniae causes primary infection in the liver is limited. We established an oral infection model that recapitulated the characteristics of liver abscess and conducted a genetic screen to identify the K. pneumoniae genes required for the development of liver abscess in mice. Twenty-eight mutants with attenuated growth in liver or spleen samples out of 2,880 signature-tagged mutants that produced the wild-type capsule were identified, and genetic loci which were disrupted in these mutants were identified to encode products with roles in cellular metabolism, adhesion, transportation, gene regulation, and unknown functions. We further evaluated the virulence attenuation of these mutants in independent infection experiments and categorized them accordingly into three classes. In particular, the class I and II mutant strains exhibited significantly reduced virulence in mice, and most of these strains were not detected in extraintestinal tissues at 48 h after oral inoculation. Interestingly, the mutated loci of about one-third of the class I and II mutant strains encode proteins with regulatory functions, and the transcript abundances of many other genes identified in the same screen were markedly changed in these regulatory mutant strains, suggesting a requirement for genetic regulatory networks for translocation of K. pneumoniae across the intestinal barrier. Furthermore, our finding that preimmunization with certain class I mutant strains protected mice against challenge with the wild-type strain implied a potential application for these strains in prophylaxis against K. pneumoniae infections.