47 research outputs found

    Characteristics of Klebsiella pneumoniae harboring QnrB32, Aac(6’)-Ib-cr, GyrA and CTX-M-22 genes

    Get PDF
    Quinolone resistance in members of the Enterobacteriaceae family is mostly due to mutations in the quinolone resistance-determining regions of topoisomerase genes. CTX-M-22 is a member of the CTX-M family which can reduce extended-spectrum β-lactamase (ESBL) production and modulate antibiotic resistance, resulting in low ceftazidime minimum inhibitory concentrations (MICs). There are four different genes in Klebsiella pneumoniae (KP4707) including qnrB32 (novel qnr allele gene, HQ704413), aac(6’)-Ib-cr (novel aac(6’)-Ib allele gene, HQ680690), gyrA (novel gyrA allele gene, HQ680691) and CTX-M-22 gene. Five point amino acid mutations Arn(N)27 → Leu(L), Val(V)129 → Ala(A), Iie(I)142 → Met(M), Gly(G)188 → Arg(R), Val(V)212 → Iie(I) were observed in the qnr32 gene when compared to qnrB1. Of all qnrB alleles, a novel variant of the qnrB32 gene, with qnrB31, had the highest amino acid homology. Three point amino acid mutations including Trp(W)105 → Arg(R), Asp(D)182 → Tyr(Y) and Val(V)201 → Asp(D) were observed in aac(6’)-Ib-cr gene, when compared to GenBank number AF479774. New variants of qnr32, aac(6’)-Ib-cr, gyrA and CTX-M-22 or other genotype determinants continuously appear in different genomic sites and also outside the Enterobacteriaceae family

    Characterization of blaOxA-23 gene regions in isolates of Acinetobacter baumannii

    Get PDF
    Background/purposeTo investigate the characterization of blaOxA-23 gene regions in isolates of Acinetobacter baumannii from Taizhou Municipal Hospital.MethodsFifty-nine non-repetitive, multiresistant (including imipenem-resistant) isolates of A. baumannii were recovered from clinical infections in hospitalized patients from January 2010 to August 2011 in Taizhou Municipal Hospital (affiliated with Taizhou University) in China. These isolates were genotyped using pulsed-field gel electrophoresis (PFGE). blaOxA-23 β-lactamase and associated genetic structures were analyzed using polymerase chain reaction (PCR), and recombination plasmids were analyzed by BamHI- or SacI- restriction enzyme digestion; predicted promoter structures of blaOxA-23 genes were determined and compared using protein-protein BLAST analysis.ResultsFifteen out of 59 isolates expressing imipenem-resistant A. baumannii clinical isolates acquired either a blaOxA-23 β-lactamase gene. A new gene cluster (ISAba1-blaOxA-23-AMP) with three previously identified transposons (Tn2006, Tn2007, and Tn2008) and one previously identified gene cluster (ISAba1- blaOxA-23) was found in the isolates. Recombination plasmids were analyzed by restriction enzyme digestion.ConclusionOur results indicate that pattern A was the most prevalent molecular type based on PFGE, and that different clones might be widespread with a majority of ISAba1-blaOxA-23 clonal lineages in the 15 PCR positive isolates of A. baumannii in the hospital

    Run-to-Run Control for Active Balancing of Lithium Iron Phosphate Battery Packs

    Get PDF
    \ua9 1986-2012 IEEE. Lithium iron phosphate battery packs are widely employed for energy storage in electrified vehicles and power grids. However, their flat voltage curves rendering the weakly observable state of charge are a critical stumbling block for charge equalization management. This paper focuses on the real-time active balancing of series-connected lithium iron phosphate batteries. In the absence of accurate in situ state information in the voltage plateau, a balancing current ratio (BCR) based algorithm is proposed for battery balancing. Then, BCR-based and voltage-based algorithms are fused, responsible for the balancing task within and beyond the voltage plateau, respectively. The balancing process is formulated as a batch-based run-to-run control problem, as the first time in the research area of battery management. The control algorithm acts in two timescales, including timewise control within each batch run and batchwise control at the end of each batch. Hardware-in-the-loop experiments demonstrate that the proposed balancing algorithm is able to release 97.1% of the theoretical capacity and can improve the capacity utilization by 5.7% from its benchmarking algorithm. Furthermore, the proposed algorithm can be coded in C language with the binary code in 118 328 bytes only and, thus, is readily implementable in real time

    Arctic upper air observations on Chinese Arctic Research Expedition 1999

    Get PDF
    The Institute of Atmospheric Physics, Chinese Academy of Sciences, planned and operated the "Arctic Upper Air Observation 1999" program on the Chinese Arctic Research Expedition co-sponsored by 7 Chinese ministries and institutions from July 1 through September 9,1999. The atmospheric parameters and ozone concentration were measured mainly at two locations in the Chukchi Sea. Preliminary study has been done on the diurnal variation of the atmospheric boundary layer temperature inversion and ozone variation in 7 days. The results show : Arctic boundary layer temperature inversion efficiently prevents heat and mass exchange between the atmosphere and surface; and tropospheric processes can be related to the total ozone variation

    Impact on urban river water quality and pollution control of water environmental management projects based on SMS-Mike21 coupled simulation

    No full text
    Abstract To explore the impact of expanding Nanyang Sewage Purification Center (NSPC) on the main sewage discharge area of Bai River, we constructed a 2D hydrodynamic-water quality model based on surface water modeling system (SMS) and Mike21. Simulating three sewage discharge conditions in wet, normal, and dry season, we evaluated three indicators (COD, NH3-N, and BOD5) by the single-factor pollution index and provided recommendations for water environment management. The results showed that, maximum absolute error of water level was 0.08 m, percentage bias coefficient of COD, NH3-N and BOD5 were 19.3%, 16.2% and 23.1%, indicating the SMS and Mike21 coupling model was applicable; water quality of the assessment section were upgraded from the original class IV, V, V (Condition 1) to class IV, III, II (Condition 2) and class IV, III, III (Condition 3) in the wet, normal and dry season, indicating that NSPC's expansion had improved the water quality of the assessment section; as the primary pollutant, BOD5 concentration in the downstream was lower than the upstream, which was due to the dilution effect of river. Therefore, on the basis of expanding NSPC, we recommend to remediation of BOD5 by physical, chemical, and biological methods. This study broadens new ideas for the application of Mike21, and provide a reference for the prevention and improvement of river water pollution in urban areas
    corecore