78 research outputs found

    Saline Flush versus Chest x ray in Confirmation of Central Venous Catheter Placement; a Diagnostic Accuracy Study

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    Introduction: Central venous catheterization (CVC) is a commonly performed procedure in critically ill patients of emergency department. This study was designed to compare the diagnostic accuracy of saline flush with CXR in confirmation of above-the-diaphragm CVC placement. Methods: This prospective cross sectional study was conducted on adult patients in need of CVC placement in emergency department. Placement Confirmation was performed with saline flush method and CXR, then chest computed tomography (CT) was performed as the gold standard. The screening performance characteristics of the two methods were calculated and compared using SPSS 21 and STATA 11. Results: 103 cases with the mean age of 57.18±9.3 (35 -80) years were studied (52.4% male). The mean duration of procedure was 2.5±1.24 in saline flush and 32.11±5.52 minutes in CXR method (P<0.001(. The area under the ROC curves for saline flush and CXR in confirmation of CVC placement were 0.90 (95%CI: 0.70 – 0.100) and 0.80 (95%CI: 0.55 – 0.100), respectively (p = 0.317). The sensitivity, specificity, positive and negative predictive value, and positive and negative likelihood ratio of  saline flush were 80%, 100%, 100, 98.9%, Infinity, and 0.01, respectively. These measures were 60%, 100%, 100%, 98%, Infinity, and 0.02 for CXR, respectively. Conclusion: It seems that saline flush method could be considered as a safe, rapid, and accurate bedside method for CVC placement confirmation in emergency department

    Energy management of virtual power plant considering distributed generation sizing and pricing

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    UID/EMS/00667/2019The energy management of virtual power plants faces some fundamental challenges that make it complicated compared to conventional power plants, such as uncertainty in production, consumption, energy price, and availability of network components. Continuous monitoring and scaling of network gain status, using smart grids provides valuable instantaneous information about network conditions such as production, consumption, power lines, and network availability. Therefore, by creating a bidirectional communication between the energy management system and the grid users such as producers or energy applicants, it will afford a suitable platform to develop more efficient vector of the virtual power plant. The paper is treated with optimal sizing of DG units and the price of their electricity sales to achieve security issues and other technical considerations in the system. The ultimate goal in this study to determine the active demand power required to increase system loading capability and to withstand disturbances. The effect of different types of DG units in simulations is considered and then the efficiency of each equipment such as converters, wind turbines, electrolyzers, etc., is achieved to minimize the total operation cost and losses, improve voltage profiles, and address other security issues and reliability. The simulations are done in three cases and compared with HOMER software to validate the ability of proposed model.publishersversionpublishe

    OISA: Architecting an Optical In-Sensor Accelerator for Efficient Visual Computing

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    Targeting vision applications at the edge, in this work, we systematically explore and propose a high-performance and energy-efficient Optical In-Sensor Accelerator architecture called OISA for the first time. Taking advantage of the promising efficiency of photonic devices, the OISA intrinsically implements a coarse-grained convolution operation on the input frames in an innovative minimum-conversion fashion in low-bit-width neural networks. Such a design remarkably reduces the power consumption of data conversion, transmission, and processing in the conventional cloud-centric architecture as well as recently-presented edge accelerators. Our device-to-architecture simulation results on various image data-sets demonstrate acceptable accuracy while OISA achieves 6.68 TOp/s/W efficiency. OISA reduces power consumption by a factor of 7.9 and 18.4 on average compared with existing electronic in-/near-sensor and ASIC accelerators.Comment: 7 page

    Analytic Solution to Integral Equations of Liquid State Theories for Potentials with a Hard Core at Low Densities

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    We present in this paper a general analytical solution to the integral equations of liquid state theories (Born-Green-Yvon, hyper-netted-chain, and Percus-Yevick Equations) at low-density limit for potentials with a hard core. For the specific case of the Lennard-Jones potential with a hard core, we have derived an analytical function for the radial distribution function at high temperature and low density. We have noted that this function has two humps which is the characteristic feature of the radial distribution function at low densities. In addition, this function has been used to calculate the third virial coefficient for such a fluid exactly. We see that for the especial case of Lennard-Jones fluid with a hard core, which its radial distribution function has explicitly been calculated at high temperatures, the correct behavior of the third virial coefficient with temperature is obtained. The magnitude of hard-core diameter has significant effect on the thermodynamic properties of fluid: for instance, when the diameter changes only by a few percent the third virial coefficient may change more than 100%. The hard-core diameter decreases when temperature increases. The reduction is less than 20%. For the supercritical fluid, the calculated compression factor and internal energy are in good agreement with those obtained from the simulation for the Lennard-Jones fluid

    Role of surface recombination in perovskite solar cells at the interface of HTL/CH3NH3PbI3

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    In order to achieve the highest performance of organometal trihalide perovskite solar cells, it is required to recognize the dominant mechanisms which play a key role in a perovskite material. In the following studies, we have focused on the interfacial recombination between the hole transporting layer (HTL) and the perovskite CH3NH3PbI3 in solar cell devices with p–i–n architecture. It has been shown that Cu:NiOx used as HTL drastically decreases a short–circuit photocurrent (Jsc) and an open–circuit voltage (Voc). However, we have found that an addition of PTAA thin layer improves cells quality and, as a consequence, the efficiency of such solar cells increases by 2%. Here, we explain both Jsc and Voc losses with a theory of the "dead layer" of perovskite material where a very high surface recombination occurs. We demonstrate the numerical and experimental studies by the means of series detailed analyses to get in–depth understanding of the physical processes behind it. Using a drift–diffusion model, it is shown that the presence of a parasitic recombination layer influences mostly the current distribution in the simulated samples explaining Jsc and Voc losses. The following results could be useful for improving the quality of perovskite solar cells

    Evaluation of the Effect of Intravenous Ondansetron versus Placebo before Anesthesia on Vomiting after Endoscopy and Colonoscopy Procedures

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    Background: Vomiting is a common complication after endoscopic procedures in children. Different medications could be administered to control vomiting after endoscopy. The goal of this study is to evaluate anti-emetic effects of ondansetron in children who undergo endoscopic procedures.Methods: In this clinical randomized trial, 198 children (103 female/95 male) were randomly assigned into one of the following two studied groups. Case group (G1): Fentanyl 1 µg/kg + propofol 2.5 mg/kg + ondansetron 0.15 mg/kg and control group (G2): Fentanyl 1 µg/kg + propofol 2.5 mg/kg + 2 cc normal saline.Results: The mean age was 6.3 ± 3.5 years (6.2 ± 3.6 years in G1 vs. 6.4 ± 3.5 years in G2). The most common cause of endoscopy procedure in both groups was hematochezia. Vomiting, recovery time, Paediatric Anesthesia Emergence Delirium (PAED), and Aldrete scores were compared. Rate of vomiting after recovery and Aldrete score were significantly different between the two groups.Conclusions:Ondansetron is effective in controlling vomiting after colonoscopy and upper gastrointestinal endoscopic procedures. Also, patients in intervention group experienced better recovery time

    Cytotoxic activity of the genus Ferula (Apiaceae) and its bioactive constituents

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    Objective: The genus Ferula L. includes perennial flowering plants belonging to the Apiaceae family. This genus is a rich source of biologically active phytochemicals such as sulfur-containing derivatives, coumarins, sesquiterpenes, sesquiterpene lactones, sesquiterpene coumarins, glucuronic acid, galactose, arabinose, rhamnose, and daucane esters. Over the last decade, considerable attention has been paid to biological activities of these compounds; it is assumed that the most prominent biological features of the genus Ferula are their cytotoxic effects. This article discusses cytotoxic activity of the genus Ferula and their important compounds. Methods: In this mini-review article, papers published from 1990 to April 2016 were included and the following information was discussed; cytotoxic activity of the genus Ferula and their important compounds, the type of cell line used in vitro, concentrations of the extracts/active compound that were used, and the underlying mechanisms of action through which Ferula-related chemicals induced cytotoxicity. In addition, we explained different mechanisms of action through which the active constituents isolated from Ferula, could decrease cellular growth. Conclusion: It is highly recommended that potent and effective compounds that were isolated from Ferula plants and found to be appropriate as adjuvant therapy for certain diseases, should be identified. Also, the versatile biological activities of sesquiterpene coumarins suggest them as promising agents with a broad range of biological applications to be used in the future
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