106 research outputs found
Chemical vapor-deposited carbon nanofibers on carbon fabric for supercapacitor electrode applications
Entangled carbon nanofibers (CNFs) were synthesized on a flexible carbon fabric (CF) via water-assisted chemical vapor deposition at 800A degrees C at atmospheric pressure utilizing iron (Fe) nanoparticles as catalysts, ethylene (C2H4) as the precursor gas, and argon (Ar) and hydrogen (H-2) as the carrier gases. Scanning electron microscopy, transmission electron microscopy, and electron dispersive spectroscopy were employed to characterize the morphology and structure of the CNFs. It has been found that the catalyst (Fe) thickness affected the morphology of the CNFs on the CF, resulting in different capacitive behaviors of the CNF/CF electrodes. Two different Fe thicknesses (5 and 10 nm) were studied. The capacitance behaviors of the CNF/CF electrodes were evaluated by cyclic voltammetry measurements. The highest specific capacitance, approximately 140 F g(-1), has been obtained in the electrode grown with the 5-nm thickness of Fe. Samples with both Fe thicknesses showed good cycling performance over 2,000 cycles
A new method of synthesis of bicyclic compounds
This article does not have an abstract
Differential disgust responding in people with cancer and implications for psychological wellbeing
Objectives: Evidence suggests that disgust responses, known to negatively affect psychological wellbeing, may differ in people with cancer. We performed the first quantitative investigation of three discrete types of disgust trait - disgust propensity, sensitivity, and self-directed disgust - in people diagnosed with a broad range of cancers (versus cancer-free controls), and explored their associations with psychological wellbeing. Design: In a cross-sectional survey design, 107 participants with heterogeneous cancer diagnoses, recruited from cancer charities and support groups, were matched with cancer-free controls by age and gender. Outcome measures: Measures of the three disgust traits were taken alongside measures of anxiety and depression. Results: Disgust sensitivity and physical self-disgust were significantly higher in the cancer than control sample, while disgust propensity and behavioural self-disgust were lower. The disgust traits had a different pattern of associations to psychological wellbeing across the two groups, with disgust sensitivity predicting depressive symptoms to a significantly greater extent in the cancer than control group. Conclusions: People with cancer differ from matched controls in their disgust responses and these responses have significant predictive relationships with aspects of their psychological wellbeing. The results suggest that emotion-based interventions may be useful for improving psychological wellbeing in people with cancer
Rhizotoxicity of aluminate and polycationic aluminium at high pH
Although monomeric Al species are often toxic in acidic soils, the effects of the aluminate ion (Al(OH)4-) on roots grown in alkaline media are still unclear. Dilute, alkaline (pH 9.5) nutrient solutions were used to investigate the effects of Al(OH)4- on root growth of mungbean (Vigna radiata L.). Root growth was reduced by 13 % after 3 d growth in solutions with an Al(OH)4- activity of 16 ΞΌM and no detectable polycationic Al (Al13). This decrease in root growth was associated with the formation of lesions on the root tips (due to the rupturing of the epidermal and outer cortical cells) and a slight limitation to root hair growth (particularly on the lateral roots). When roots displaying these symptoms were transferred to fresh Al(OH)4- solutions for a further 12 h, no root tip lesions were observed and root hair growth on the lateral roots improved. The symptoms were similar to those induced by Al13 at concentrations as low as 0.50 ΞΌM Al which are below the detection limit of the ferron method. Thus, Al(OH)4- is considered to be non-toxic, with the observed reduction in root growth in solutions containing Al(OH)4- due to the gradual formation of toxic Al13 in the bulk nutrient solution resulting from the acidification of the alkaline nutrient solution by the plant roots
Clinically and microbiologically derived azithromycin susceptibility breakpoints for Salmonella enterica serovars Typhi and Paratyphi A.
Azithromycin is an effective treatment for uncomplicated infections with Salmonella enterica serovar Typhi and serovar Paratyphi A (enteric fever), but there are no clinically validated MIC and disk zone size interpretative guidelines. We studied individual patient data from three randomized controlled trials (RCTs) of antimicrobial treatment in enteric fever in Vietnam, with azithromycin used in one treatment arm, to determine the relationship between azithromycin treatment response and the azithromycin MIC of the infecting isolate. We additionally compared the azithromycin MIC and the disk susceptibility zone sizes of 1,640 S. Typhi and S. Paratyphi A clinical isolates collected from seven Asian countries. In the RCTs, 214 patients who were treated with azithromycin at a dose of 10 to 20 mg/ml for 5 to 7 days were analyzed. Treatment was successful in 195 of 214 (91%) patients, with no significant difference in response (cure rate, fever clearance time) with MICs ranging from 4 to 16 ΞΌg/ml. The proportion of Asian enteric fever isolates with an MIC of β€ 16 ΞΌg/ml was 1,452/1,460 (99.5%; 95% confidence interval [CI], 98.9 to 99.7) for S. Typhi and 207/240 (86.3%; 95% CI, 81.2 to 90.3) (P 16 ΞΌg/ml and to determine MIC and disk breakpoints for S. Paratyphi A
Human Genome-Wide RNAi Screen for Host Factors That Modulate Intracellular Salmonella Growth
Salmonella enterica is a bacterial pathogen of humans that can proliferate within epithelial cells as well as professional phagocytes of the immune system. While much has been learned about the microbial genes that influence the infectious process through decades of intensive research, relatively little is known about the host factors that affect infection. We performed a genome-wide siRNA screen to identify host genes that Salmonella enterica serovar Typhimurium (S. typhimurium) utilizes to facilitate growth within human epithelial cells. In this screen, with siRNAs targeting every predicted gene in the human genome, we identified 252 new human-host-susceptibility factors (HSFs) for S. typhimurium. We also identified 39 genes whose silencing results in increased intracellular growth of S. typhimurium. The HSFs identified are regulated most centrally by NFΞΊB and associate with each other through an extremely dense network of interactions that center around a group of kinases. Most genes identified were not previously appreciated as playing roles in the intracellular lifecycle of S. enterica. Numerous HSFs identified with interesting characteristics that could play plausible roles in mediating intracellular microbial growth are discussed. Importantly, this study reveals significant overlap between the host network that supports S. typhimurium growth within human epithelial cells and the one that promotes the growth of Mycobacterium tuberculosis within human macrophages. In addition to providing much new information about the molecular mechanisms underlying S. enterica-host cell interplay, all 252 HSFs identified are candidates for new anti-microbial targets for controlling S. enterica infections, and some may provide broad-spectrum anti-microbial activity
Evaluation of a modified double-disc synergy test for detection of extended spectrum Ξ²-lactamases in AMPC Ξ²-lactamase-producing proteus mirabilis
The detection of extended-spectrum Ξ²-lactamases (ESBLs) in
gram-negative bacteria that produce AmpC Ξ²-lactamases is
problematic. In the present study, the performance of modified
double-disc synergy test (MDDST) that employs a combination of cefepime
and piperacillin-tazobactam for the detection of proteus mirabilis
producing extended spectrum and AmpC Ξ²-lactamases was evaluated
and compared with double-disc synergy test (DDST) and NCCLS phenotypic
disc confirmatory test (NCCLS-PDCT). A total of 90 clinical isolates of
P. mirabilis , which met the CLSI (Clinical and Laboratory Standards
Institute) screening criteria that these had broth microdilution (BMD)
MIC of β₯2 mg/mL for at least one extended spectrum cephalosporin
[ceftazidime (CAZ), cefotaxime (CTX) and cefpodoxime], were selected
for the study. MDDST detected ESBLs in 40/90 of the isolates, whereas
DDST detected ESBLs in only 25 isolates. NCCLS-PDCT could detect ESBLs
in 39 isolates using CAZ and CAZ + clavulanic acid (CLA) combination,
whereas CTX and CTX + CLA combination could detect only 37 isolates as
ESBL positive. As many as 34/40 ESBL positive isolates were confirmed
to be AmpC Ξ²-lactamase positive by the modified three-dimensional
test (MTDT). MDDST and NCCLS-PDCT could detect ESBLs in all the 34 AmpC
positive isolates, whereas DDST could detect ESBLs in only 19 isolates.
The study demonstrated that MDDST is superior to DDST and as sensitive
as NCCLS-PDCT. However, MDDST seems to have enhanced potential for the
detection of ESBLs in AmpC Ξ²-lactamase-producing P. mirabilis
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