12,151 research outputs found

    Novel SOFC Anodes for the Direct Electrochemical Oxidation of Hydrocarbon

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    This paper describes recent developments in solid-oxide fuel cells (SOFC) that use Cu-based cermets as the anode for direct oxidation of hydrocarbon fuels, including liquids such as gasoline, to generate electrical power without the need for first reforming that fuel to H2. Cu-YSZ cermets were found to be stable in hydrocarbon environments, but exhibited low performance for direct oxidation. Reasonable power densities could only be achieved with the addition of a catalytic oxide, like ceria, with the Cu cermet. Electrochemical oxidation studies demonstrated that the initial products for reaction depend on the catalytic oxide. Finally, the effect of sulfur impurities in the fuel is discussed

    Drivers of Cost in Primary Single-Level Lumbar Fusion Surgery

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    STUDY DESIGN: Retrospective cohort. OBJECTIVES: Allocating cost is challenging with traditional hospital accounting. Time-driven activity-based costing (TDABC) is an efficient method to accurately assign cost. We sought to characterize the variation in direct total hospital cost (THC) among both lumbar fusion approaches and surgeons. METHODS: Patients were treated with single-level anterior interbody (ALIF), lateral interbody (LLIF), transforaminal interbody (TLIF), instrumented posterolateral (PLF) or in-situ fusion (ISF) for degenerative disease. Process maps were developed for preoperative, intraoperative and postoperative care. THC was composed of implant, medication, other supply, and personnel costs. Linear regression and descriptive statistics were used to analyze THC variation. RESULTS: A total of 696 patients underwent surgery by 8 surgeons. Approximately 50% of THC variation was associated with procedure choice while patient characteristics explained 10%. Implants (including biologics) accounted for 45% of cost. With reference to PLF, THC ranged from 0.6x (ISF) to 1.7x (LLIF). Implant cost ranged from 2.5x reference (LLIF) to 0.1x (ISF). There was a 1.7x difference between the highest THC surgeon and the lowest. The fusion type with the highest THC variation was TLIF. The surgeon with the highest TLIF THC was 1.5x more expensive than the surgeon with the lowest. CONCLUSIONS: Surgeon-based choices have the greatest effect on THC variation and represent the largest opportunities for cost savings. Primary single-level lumbar fusion THC is driven primarily by fusion type. Implants, including biologics, account for nearly half this cost. Future work should incorporate outcomes data to characterize the differential value conferred by higher THC fusions

    Privacy-preserving outsourced support vector machine design for secure drug discovery

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    AXA Research Fund, Singapore Management Universit

    Metabolite essentiality elucidates robustness of Escherichia coli metabolism

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    Complex biological systems are very robust to genetic and environmental changes at all levels of organization. Many biological functions of Escherichia coli metabolism can be sustained against single-gene or even multiple-gene mutations by using redundant or alternative pathways. Thus, only a limited number of genes have been identified to be lethal to the cell. In this regard, the reaction-centric gene deletion study has a limitation in understanding the metabolic robustness. Here, we report the use of flux-sum, which is the summation of all incoming or outgoing fluxes around a particular metabolite under pseudo-steady state conditions, as a good conserved property for elucidating such robustness of E. coli from the metabolite point of view. The functional behavior, as well as the structural and evolutionary properties of metabolites essential to the cell survival, was investigated by means of a constraints-based flux analysis under perturbed conditions. The essential metabolites are capable of maintaining a steady flux-sum even against severe perturbation by actively redistributing the relevant fluxes. Disrupting the flux-sum maintenance was found to suppress cell growth. This approach of analyzing metabolite essentiality provides insight into cellular robustness and concomitant fragility, which can be used for several applications, including the development of new drugs for treating pathogens.Comment: Supplements available at http://stat.kaist.ac.kr/publication/2007/PJKim_pnas_supplement.pd

    Far-ultraviolet Emission-line Morphologies of the Supernova Remnant G65.3+5.7

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    We present the first far-ultraviolet (FUV) emission-line morphologies of the whole region of the supernova remnant (SNR) G65.3+5.7 using the FIMS/SPEAR data. The morphologies of the C IV {\lambda}{\lambda}1548, 1551, He II {\lambda}1640, and O III] {\lambda}{\lambda}1661, 1666 lines appear to be closely related to the optical and/or soft X-ray images obtained in previous studies. Dramatic differences between the C IV morphology and the optical [O III] {\lambda}5007 image provide clues to a large resonant-scattering region and a foreground dust cloud. The FUV morphologies also reveal the overall distribution of various shocks in different evolutionary phases and an evolutionary asymmetry between the east and the southwest sides in terms of Galactic coordinates, possibly due to a Galactic density gradient in the global scale. The relative X-ray luminosity of G65.3+5.7 to C IV luminosity is considerably lower than those of the Cygnus Loop and the Vela SNRs. This implies that G65.3+5.7 has almost evolved into the radiative stage in the global sense and supports the previous proposal that G65.3+5.7 has lost its bright X-ray shell and become a member of mixed-morphology SNRs as it has evolved beyond the adiabatic stage.Comment: 6 pages, 3 figures, accepted for publication in The Ap

    Fast, Interactive Worst-Case Execution Time Analysis With Back-Annotation

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    Abstract—For hard real-time systems, static code analysis is needed to derive a safe bound on the worst-case execution time (WCET). Virtually all prior work has focused on the accuracy of WCET analysis without regard to the speed of analysis. The resulting algorithms are often too slow to be integrated into the development cycle, requiring WCET analysis to be postponed until a final verification phase. In this paper we propose interactive WCET analysis as a new method to provide near-instantaneous WCET feedback to the developer during software programming. We show that interactive WCET analysis is feasible using tree-based WCET calculation. The feedback is realized with a plugin for the Java editor jEdit, where the WCET values are back-annotated to the Java source at the statement level. Comparison of this treebased approach with the implicit path enumeration technique (IPET) shows that tree-based analysis scales better with respect to program size and gives similar WCET values. Index Terms—Real time systems, performance analysis, software performance, software reliability, software algorithms, safety I

    Intrathyroidal Parathyroid Carcinoma: An Atypical Thyroid Lesion

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    Parathyroid carcinoma is a rare endocrine malignancy that is typically difficult to diagnose at presentation. Here, we report a 63 year-old man who had symptomatic hypercalcemia. Investigations revealed a thyroid nodule and a lateral neck mass that was biopsied and diagnosed as “suspicious for a neuroendocrine neoplasm.” He underwent total thyroidectomy with central and left neck node dissection. Histology and immunohistochemistry revealed an intrathyroidal angioinvasive parathyroid carcinoma with lymph node metastases. The tumor showed loss of parafibromin expression; germline testing revealed no pathogenic germline variants of CDC73, suggesting either a cryptic germline variant or a sporadic malignancy. Multiple pulmonary nodules consistent with metastatic disease explained persistent hypercalcemia and the patient was treated with denosumab as well as Sorafenib resulting in early regression of the lung nodules. This case illustrates an unusual parathyroid carcinoma with respect to anatomic presentation and the importance of complete pathological workup in securing the diagnosis. The management of these rare malignancies is discussed

    Multi-dimensional data indexing and range query processing via Voronoi diagram for internet of things

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    In a typical Internet of Things (IoT) deployment such as smart cities and Industry 4.0, the amount of sensory data collected from physical world is significant and wide-ranging. Processing large amount of real-time data from the diverse IoT devices is challenging. For example, in IoT environment, wireless sensor networks (WSN) are typically used for the monitoring and collecting of data in some geographic area. Spatial range queries with location constraints to facilitate data indexing are traditionally employed in such applications, which allows the querying and managing the data based on SQL structure. One particular challenge is to minimize communication cost and storage requirements in multi-dimensional data indexing approaches. In this paper, we present an energy- and time-efficient multidimensional data indexing scheme, which is designed to answer range query. Specifically, we propose data indexing methods which utilize hierarchical indexing structures, using binary space partitioning (BSP), such as kd-tree, quad-tree, k-means clustering, and Voronoi-based methods to provide more efficient routing with less latency. Simulation results demonstrate that the Voronoi Diagram-based algorithm minimizes the average energy consumption and query response time
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