200 research outputs found

    Correlation of ciprofloxacin resistance with the AdeABC efflux system in Acinetobacter baumannii clinical isolates

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    Background: Acinetobacter baumannii is one of the most important pathogens capable of colonization in burn patients, leading to drug-resistant wound infections. This study evaluated the distribution of the AdeABC efflux system genes and their relationship to ciprofloxacin resistance in A. baumannii isolates collected from burn patients. Methods: A total of 68 A. baumannii clinical strains were isolated from patients hospitalized in Motahari Burns Center in Tehran, Iran. Ciprofloxacin susceptibility was tested by the disk diffusion and agar dilution methods. PCR amplification of the adeRS-adeB drug efflux genes was performed for all resistant and susceptible isolates. To assess the role of the drug efflux pump in ciprofloxacin susceptibility, carbonyl cyanide 3-chlorophenylhydrazone (CCCP) was used as an efflux pump inhibitor (EPI). Results: Approximately 95.6% of the Acinetobacter isolates were resistant to ciprofloxacin, with minimum inhibitory concentration (MIC) values ranging from 4 to ≥128 μg/mL. The susceptibility of 86.1% of the resistant isolates increased by factors of 2 to 64 in the presence of CCCP. All resistant isolates were positive for the adeRS-adeB genes, and 73.2% of them had mutations in the AdeRS regulatory system. Conclusions: The results showed that AdeABC genes are common in A. baumannii, which might be associated with ciprofloxacin non-susceptibility, as indicated by the observed linkage to the presence of the genes essential for the activity of the AdeABC, several single mutations occurring in the adeRS regulatory system, and an increase of ciprofloxacin susceptibility in the presence of a CCCP EPI. © The Korean Society for Laboratory Medicin

    Application of silicon-polymer composite varistors to protect sensitive medical imaging circuits and performing better voltage bias for SiPMs

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    Nowadays, Silicon photomultipliers (SiPM) become a reasonable choice for Time-of-Flight Positron Emission Tomography (TOF-PET). To achieve the best performance of SiPMs, it is necessary to adjust a suitable voltage bias. In this article, we are using varistors which protect SiPM from voltage fluctuations. The silicon-polymer composite varistors prepared using hot press method have been investigated. Research on (current-voltage) characteristics of samples shows that by increasing silicon content in the mixture, the breakdown voltage decreases from 110 V to 70 V. The results also show that increasing silicon content decreases the potential barrier height from 0.29 eV to 0.26 eV, however, leakage current increases. Increasing silicon content increases nonlinear coefficient from 4.1 to 4.8. Using these techniques gives us ability to produce suitable surge protector for medical imaging modalitie

    Religious coping and quality of life in women with breast cancer

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    Background: The aim of this study was to assess the predictive role of religious coping in quality of life of breast cancer patients. Materials and Methods: This multi-center cross-sectional study was conducted in Tehran, Iran, from October 2014 to May 2015. A total of 224 women with breast cancer completed measures of socio-demographic information, religious coping (brief RCOPE), and quality of life (FACT-B). Data were analyzed using descriptive statistics and the t-test, ANOVA, and linear regression analysis. Results: The mean age was 47.1 (SD=9.07) years and the majority were married (81.3). The mean score for positive religious coping was 22.98 (SD=4.09) while it was 10.13 (SD=3.90) for negative religious coping. Multiple linear regression showed positive and negative religious coping as predictor variables explained a significant amount of variance in overall QOL score (R2=.22, P=.001) after controlling for socio-demographic, and clinical variables. Positive religious coping was associated with improved QOL (β=0.29; p=0.001). In contrast, negative religious coping was significantly associated with worse QOL (β=-0.26; p=0.005). Conclusions: The results indicated the used types of religious coping strategies are related to better or poorer QOL and highlight the importance of religious support in breast cancer care

    Simultaneous effect of temperature and site altitude on generators output

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    The effect of environmental conditions of the site must be considered as one of the most important aspects of designing generators as well as theoretic calculations and considerations. The real amounts which are measurable on the sites under real conditions are usually different from the rated values of the generators. In this paper we exerted this consideration and a typical model of generator produced by Ansaldo Energia was selected and studied. The material of the generator application guide and the measured values on site are used to get related curves of the environmental conditions effect, such as the effect the site altitude and the ambient temperature, on generator rated values. The practical and measured values of this model of generator which has been installed on Parand and Oroumieh sites in Iran are used for verification of the results of this paper and the related error is calculated. We claim this technical research has not been done before with such mentioned considerations and necessities. This paper gives the necessary instruction to evaluate the applicability and the generator characteristic data at different operating conditions (load, voltage, power factor, site and cooling condition). This study enables the designer to evaluate the generator behavior under the customer requirements and environmental conditions as well as to prepare the necessary proposed documentation for the client. © 2011 Praise Worthy Prize S.r.l. - All rights reserved

    Sexual orientation, theory of mind and empathy: A comparison of male homosexual and male and female heterosexuals

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    Background: Researchers have been investigating similarities of and differences between homosexuals and heterosexuals for past few decades. Several studies have shown that in the particular domain (e.g., spatial ability), male homosexuals would resemble female heterosexuals better than male heterosexuals. Executive function, however, has received more attention than social cognition in this line of research. Methods: This study focuses on theory of mind and empathy as two important components of social cognition in male homosexuals (N=14), male heterosexuals (N=15) and female heterosexuals (N=14). Results: Applying Reading the Mind in the Eyes test and the Empathy Quotient, no significant difference between groups was identified. Conclusion: This study suggests that similarities of male homosexuals and female heterosexuals may be confined to executive function and not extended to some social cognition abilities like theory of mind or empathy

    Optimal FRP Jacket Placement in RC Frame Structures Towards a Resilient Seismic Design

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    This paper proposes an optimal plan for seismically retrofitting reinforced concrete (RC) frame structures. In this method, the columns are wrapped by fiber-reinforced polymer (FRP) layers along their plastic hinges. This technique enhances their ductility and increases the resiliency of the structure. Two meta-heuristic algorithms (i.e., genetic algorithm and particle swarm optimization) are adopted for this purpose. The number of FRP layers is assumed to be the design variable. The objective of the optimization procedure was to provide a uniform usage of plastic hinge rotation capacity for all the columns, while minimizing the consumption of the FRP materials. Toward this aim, a single objective function containing penalty terms is introduced. The seismic performance of the case study RC frame was assessed by means of nonlinear pushover analyses, and the capacity of the plastic hinge rotation for FRP-confined columns was evaluated at the life safety performance level. The proposed framework was then applied to a non-ductile low-rise RC frame structure. The optimal retrofit scheme for the frame was determined, and the capacity curve, inter-story drift ratios, and fragility functions were computed and compared with alternative retrofit schemes. The proposed algorithm offers a unique technique for the design of more resilient structures.Open access journalThis item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]

    On the Dynamic Capacity of Concrete Dams

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    The purpose of this joint contribution is to study the maximum dynamic load concrete dams can withstand. The so-called "dynamic capacity functions" for these infrastructures seems now technically and commercially feasible thanks to the modern finite element techniques, hardware capabilities, and positive experiences collected so far. The key topics faced during the dynamic assessment of dams are also discussed using different point of view and examples, which include: the selection of dynamic parameters, the progressive level of detail for the numerical simulations, the implementation of nonlinear behaviors, and the concept of the service and collapse limit states. The approaches adopted by local institutions and engineers on the subject of dam capacity functions are discussed using the authors' experiences, and an overview of time and resources is outlined to help decision makers. Three different concrete dam types (i.e., gravity, buttress, and arch) are used as case studies with different complexities. Finally, the paper is wrapped up with a list of suggestions for analysts, the procedure limitations, and future research needs

    Study of direct thermal energy storage technologies for effectiveness of concentrating solar power plants

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    In this paper, numerical comparisons are devised among different direct thermal energy storage (TES) technologies of concentrating solar power (CSP) plants with possible alternatives in design, plantwide control and global economic considerations and therefore, leading the process up to the sustainable power production through the day and night. The first design is based on the conventional direct double-tank thermal energy storage CSP plant, and afterwards, the modification on the design of this plant is proposed. The modification on the plantwide control is followed by recycling the heat transfer fluid (HTF) through the solar field and decreasing the degradation of temperature of the storage in discharge period. In addition, the analogues analysis is performed towards the solutions of the stable behavior on dynamic of the storage and power production. Owing to the fact that the single-tank storage technology eliminates using an extra storage volume in process design, consequently, it decreases the capital cost of the plant, the dynamic design of the single-tank storage technology is presented. Avoiding the greater degradations of the parameters is considered and improved through the heat exchanger trains as a challenging issue in storage technologies along with the plantwide control. In this work, considerations of process control to improve the quality of storage, operational issues, and flexibility related to the selected TES technologies are discussed due to making decisions for optimal control and covering the demanded energy generated by CSP plant
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