In the present study, graphite/alumina composites are fabricated via reductive sintering of gel-casted green bodies with structurally controlled cross-linked epoxy polymers for the first time. The cross-linking degrees of polymers are tuned by the amount ratio of epoxy monomer/polyvinyl alcohol cross-linker utilized in gel-casting process. Superior electrical properties with respect to 5-fold enhanced electrical conductivity and 2-fold higher carrier mobility are successfully achieved in graphite/alumina composite fabricated from cross-linked epoxy polymer, whose phenomenon is attributed to the excellent conductive path in ceramic matrix established by highly uniform network with improved graphitization degree.
Little is known about antibiotic-resistant Gram-negative bacteria (GNB) intestinal carriage among healthcare workers (HCWs) in Vietnam. All HCWs at a tertiary intensive care units were asked to undertake weekly rectal swabs. Among 40 participants, 65% (26/40) carried extended spectrum β-lactamases (ESBL)/AmpC β-lactamase-producing
Escherichia coli.
Two HCWs colonized with ESBL/AmpC β-lactamase-producing
Klebsiella pneumoniae.
One HCW colonized with
Acinetobacter baumannii
. No one carried
Pseudomonas
spp.. A quarter (10/40) of HCWs were identified as persistent and frequent carriers. There is an urgent need to screen antibiotic-resistant GNB among HCWs and improve HCWs’ hand hygiene compliance to reduce the transmission of antibiotic-resistant GNB in the hospital.
Semi-conductive C/Al2O3 ceramic composites were successfully fabricated by a pretty simple approach, combining a powder mixture process and pulsed electric current sintering. In order to obtain homogeneous distribution of carbon contents, popular polymers were used as carbon fillers to mix with Al2O3 powder by a wet ball milling step. The sintering was conducted by pulsed electric current sintering without any special requirement of the reductive environment like in conventional sintering. Density of bulk bodies, states of carbon contents after sintering and the electrical properties were analyzed in this study. Although the density of sintered bodies and their electrical properties were not superior, those characteristics of C/Al2O3 ceramic composites in this study were still comparatively high among semi-conductive ceramics. Especially, the carrier type of semi-conductive C/Al2O3 composites could be modified easily by adding polycarboxylic acid (PCA) in the powder mixture as a dispersant.
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