Deep-trap dominated degradation of the endurance characteristics in OFET memory with polymer charge-trapping layer.

Organic field-effect transistors (OFETs) with polymer charge-trapping dielectric, which exhibit many advantages over Si-based memory devices such as low cost, light weight, and flexibility, still suffer challenges in practical application due to the unsatisfied endurance characteristics and even the lack of fundamental of behind mechanism. Here, we revealed that the degradation of endurance characteristics of pentacene OFET with poly(2-vinyl naphthalene) (PVN) as charge-storage layer is dominated by the deep hole-traps in PVN by using the photo-stimulated charge de-trapping technique with the fiber-coupled monochromatic-light probes. The depth distribution of hole-traps in PVN film of pentacene OFET is also provided.

Role of rgsA in Oxidative Stress Resistance in Pseudomonas aeruginosa.

Pseudomonas aeruginosa is a common opportunistic pathogen that causes infections in vulnerable patients including those with metabolic disorders, hematologic diseases, and malignancies, and in those who have undergone surgery. In addition, P. aeruginosa exhibits high intrinsic resistance to numerous antibiotics and tends to form biofilms rendering it even more refractory to treatment. Among the mechanisms used by P. aeruginosa to adapt to environmental stresses are those involving small regulatory RNAs (sRNAs), which are 40-500 nucleotides long and are ubiquitous in bacteria. sRNAs play important regulatory roles in various vital processes in diverse bacteria, with their quantity and diversity of regulatory functions exceeding those of proteins. In this study, we show that deletion of the sRNA, rgsA, decreased the growth rate of P. aeruginosa. Furthermore, ΔrgsA P. aeruginosa exhibited decreased ability to resist the stress induced by exposure to different concentrations and durations of peroxides in both planktonic and biofilm growth modes compared with the wild-type strain. These results highlight the role of rgsA in the defense of P. aeruginosa against oxidative stress.

Heptaplex PCR melting curve analysis for rapid detection of plasmid-mediated AmpC ß-lactamase genes.

Antimicrobial resistance mediated by plasmid-borne AmpC ß-lactamase in Gram-negative bacteria is an emerging event of significant clinical importance. Rapid and reliable detection of ampC is in urgent need for appropriate infection control. We described the development and evaluation of a heptaplex PCR melting curve analysis that could identify six groups of ampC, i.e., CIT, EBC, DHA, ACC, MOX and FOX, through predefined melting temperatures. The entire analysis could be finished within 2h for 96 samples after template DNA was prepared. We first evaluated the assay with 176 AmpC-producing isolates of Escherichia coli and Klebsiella pneumoniae, and the results showed that 36 isolates were positive for ampC, including 18 positive for DHA, 12 for CIT, 5 for EBC, and one for both DHA and EBC. These results were fully concordant with sequencing analysis whereas the comparison method, an electrophoresis-based singleplex PCR assay, missed four isolates. The assay was also used to analyze 429 randomly selected clinically relevant Gram-negative isolates involving 22 different species, and 34 isolates were found to be ampC-positive. The results again fully agreed with the sequencing analysis. We conclude that the established assay could be used for rapid and reliable detection of ampC.