Experimental investigation of thermal performance of the graphene oxide-coated plates
HEAT TRANSFER-ASIAN RESEARCH
Authors: Ghasemiasl, Ramin; Taheri, Mohammad Ali; Molana, Maysam; Raoufi, Nahid
Abstract
This paper experimentally investigates the conductive heat transfer of samples with different materials and coatings. A range of graphene oxide nanoparticle concentration has been employed. Results demonstrate that utilizing nanoparticles leads to enhancement of conductive heat transfer by 10.07% and 8.01% for EK2 and ST14 samples, respectively. The aforementioned nanoparticles also reduce coating thickness and yield an enhanced quality of the surface, in terms of mechanical properties. The convective and radiative methods of heat transfer have been ignored in this study.
Spread of an OmpK36-modified ST15 Klebsiella pneumoniae variant during an outbreak involving multiple carbapenem-resistant Enterobacteriaceae species and clones
EUROPEAN JOURNAL OF CLINICAL MICROBIOLOGY & INFECTIOUS DISEASES
Authors: Novais, A.; Rodrigues, C.; Branquinho, R.; Antunes, P.; Grosso, F.; Boaventura, L.; Ribeiro, G.; Peixe, L.
Abstract
We aim to characterise multiple ertapenem-resistant (ERT-R, n = 15) Enterobacteriaceae isolates identified as presumptive carbapenemase producers in a Portuguese hospital in a short period of time (March-July 2010). Antibiotic susceptibility patterns, beta-lactamases, genetic relatedness [pulsed-field gel electrophoresis (PFGE), multi-locus sequence typing (MLST)], plasmid content and major enterobacterial porins were investigated. Ertapenem resistance was associated with deficiencies in major porins and, in some cases, extended-spectrum beta-lactamase (ESBL) or AmpC beta-lactamase production among outbreak and non-outbreak clones. Most isolates (n = 8) corresponded to two ERT-R Klebsiella pneumoniae ST15 PFGE-types: (i) a sporadic variant (Kp-A-ERT, n = 1) presenting a premature stop codon in ompK36 and (ii) an epidemic variant (Kp-B-ERT, n = 7) exhibiting a new OmpK36 porin variant, which differed additionally in plasmid and antibiotic susceptibility profiles. ST14 (n = 1) and ST45 (n = 1) K. pneumoniae, ST131 (n = 1) and ST354 (n = 1) Escherichia coli, Enterobacter asburiae (n = 1), Enterobacter cloacae (n = 1) and Enterobacter aerogenes (n = 1) ERT-R clones were also sporadically detected. Porin changes in these isolates included non-sense mutations [ompK35, ompK36, ompF; minimum inhibitory concentration (MIC) = 4-32 mg/l], IS-mediated porin disruptions (ompK36, ompC; MIC = 12-> 32 mg/l) or alterations in the L3 loop (ompK36; MIC = 4-16 mg/l). We describe, for the first time in Portugal, the simultaneous emergence of multiple ERT-R Enterobacteriaceae species and clones in a short period of time. Moreover, our results support that a CTX-M-15-producing ST15 K. pneumoniae with an OmpK36-modified porin might successfully spread in the nosocomial setting.
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