272 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

    Interventions based on PRECEDE-PROCEED for promoting safety behaviors in Primary school boys

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    Introduction & Objective: Pedestrian injuries are a significant source of morbidity, mortality and disability among children. Prevention of these injuries is thus a major priority for public health and requires a comprehensive approach and educational strategies. The purpose of this study was designing and evaluation of an educational program, based on the PRECEED-PROCEED model for improvement of safety behavior in primary school boys. Materials & Methods: This study is a field trial carried out in 6th areas of Tehran in 2007. Participants (n=88) were 10 – 11 year old who followed by items measuring the PRECEED-PROCEED model before and after two months of intervention. The collected data were analyzed with T test, X2 and pair T test using SPSS software. Results: After participating in educational program, significant improvements were found in knowledge, attitude, behavior, enabling and reinforcing factors of the components of PRECEEDPROCEED model. Conclusion: The findings suggest the beneficial effects of educational intervention based on the PRECEDE-PROCEED model on improving the safety behavior. It can be recommended that health education plan be used on educational models

    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

    Search for the decay K+π+ννˉK^+\to \pi^+ \nu \bar\nu in the momentum region Pπ<195 MeV/cP_\pi < 195 {\rm ~MeV/c}

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    We have searched for the decay K+π+ννˉK^+ \to \pi^+ \nu \bar\nu in the kinematic region with pion momentum below the K+π+π0K^+ \to \pi^+ \pi^0 peak. One event was observed, consistent with the background estimate of 0.73±0.180.73\pm 0.18. This implies an upper limit on B(K+π+ννˉ)<4.2×109B(K^+ \to \pi^+ \nu \bar\nu)< 4.2\times 10^{-9} (90% C.L.), consistent with the recently measured branching ratio of (1.570.82+1.75)×1010(1.57^{+1.75}_{-0.82}) \times 10^{-10}, obtained using the standard model spectrum and the kinematic region above the K+π+π0K^+ \to \pi^+ \pi^0 peak. The same data were used to search for K+π+X0K^+ \to \pi^+ X^0, where X0X^0 is a weakly interacting neutral particle or system of particles with 150<MX0<250 MeV/c2150 < M_{X^0} < 250 {\rm ~MeV/c^2}.Comment: 4 pages, 2 figure

    Hybrid Turbo-Shaft Engine Digital Twinning for Autonomous Aircraft via AI and Synthetic Data Generation

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    Autonomous aircraft are the key enablers of future urban services, such as postal and transportation systems. Digital twins (DTs) are promising cutting-edge technologies that can transform the future transport ecosystem into an autonomous and resilient system. However, since DT is a data-driven solution based on AI, proper data management is essential in implementing DT as a service (DTaaS). One of the challenges in DT development is the availability of real-life data, particularly for training algorithms and verifying the functionality of DT. The current article focuses on data augmentation through synthetic data generation. This approach can facilitate the development of DT in case the developers do not have enough data to train the machine learning (ML) algorithm. The current twinning approach provides a prospective ideal state of the engine used for proactive monitoring of the engine’s health as an anomaly detection service. In line with the track of unmanned aircraft vehicles (UAVs) for urban air mobility in smart city applications, this paper focuses specifically on the common hybrid turbo-shaft in drones/helicopters. However, there is a significant gap in real-life similar synthetic data generation in the UAV domain literature. Therefore, rolling linear regression and Kalman filter algorithms were implemented on noise-added data, which simulate the data measured from the engine in a real-life operational life cycle. For both thermal and hybrid models, the corresponding DT model has shown high efficiency in noise filtration and a certain amount of predictions with a lower error rate on all engine parameters except the engine torque

    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]

    Rank Restriction for the Variational Calculation of Two-electron Reduced Density Matrices of Many-electron Atoms and Molecules

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    Variational minimization of the ground-state energy as a function of the two-electron reduced density matrix (2-RDM), constrained by necessary NN-representability conditions, provides a polynomial-scaling approach to studying strongly correlated molecules without computing the many-electron wavefunction. Here we introduce a new route to enhancing necessary conditions for NN-representability through rank restriction of the 2-RDM. Rather than adding computationally more expensive NN-representability conditions, we directly enhance the accuracy of two-particle (2-positivity) conditions through rank restriction, which removes degrees of freedom in the 2-RDM that are not sufficiently constrained. We select the rank of the particle-hole 2-RDM by deriving the ranks associated with model wavefunctions including both mean-field and antisymmetrized geminal power (AGP) wave functions. Because the 2-positivity conditions are exact for quantum systems with AGP ground states, the rank of the particle-hole 2-RDM from the AGP ansatz provides a minimum for its value in variational 2-RDM calculations of general quantum systems. To implement the rank-restricted conditions, we extend a first-order algorithm for large-scale semidefinite programming. The rank-restricted conditions significantly improve the accuracy of the energies; for example, the percentages of correlation energies recovered for HF, CO, and N2_{2} improve from 115.2%, 121.7%, and 121.5% without rank restriction to 97.8%, 101.1%, and 100.0% with rank restriction. Similar results are found at both equilibrium and non-equilibrium geometries. While more accurate, the rank-restricted NN-representability conditions are less expensive computationally than the full-rank conditions
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