1,631 research outputs found

    Low Resistance Polycrystalline Diamond Thin Films Deposited by Hot Filament Chemical Vapour Deposition

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    Polycrystalline diamond thin films with outgrowing diamond (OGD) grains were deposited onto silicon wafers using a hydrocarbon gas (CH4) highly diluted with H2 at low pressure in a hot filament chemical vapour deposition (HFCVD) reactor with a range of gas flow rates. X-ray diffraction (XRD) and SEM showed polycrystalline diamond structure with a random orientation. Polycrystalline diamond films with various textures were grown and (111) facets were dominant with sharp grain boundaries. Outgrowth was observed in flowerish character at high gas flow rates. Isolated single crystals with little openings appeared at various stages at low gas flow rates. Thus, changing gas flow rates had a beneficial influence on the grain size, growth rate and electrical resistivity. CVD diamond films gave an excellent performance for medium film thickness with relatively low electrical resistivity and making them potentially useful in many industrial applications

    Mild to moderate influenza A(H7N9) infections detected through China’s national influenza-like Illness sentinel surveillance system

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    Poster Session: News and Views from the H7N9 OutbreakBackground: The “clinical iceberg” phenomenon, where there are usually many more infected cases than is apparent symptomatically and even less so registered in the clinical setting, is a common feature of influenza disease. While this is certainly true for interpandemic influenza and the 2009 influenza A(H1N1) pandemic, this appeared to be less substantial for the Dutch A(H7N7) outbreak, and with A(H5N1) being an acknowledged exception. It remains unknown whether the “iceberg” applies to the influenza A(H7N9) virus that emerged in early 2013 in China. While the majority of laboratory-confirmed A(H7N9) cases presented with a severe clinical picture to a hospital, a small number of laboratory-confirmed cases have been identified through the sentinel influenza-like illness (ILI) surveillance system nationwide. The objective of our study was to describe the clinical characteristics of the complete case series of A(H7N9) cases as of May 15, 2013, that were identified through routine testing by the ILI sentinel surveillance system. Materials and Methods: ILI sentinel surveillance in China is conducted through a network of 554 hospitals across the country, with the total number of outpatient and/or emergency department visits and the number of patients fitting the WHO standard ILI case definition reported weekly online to the China CDC, and 10-15 nasopharyngeal swabs collected from ILI patients each week for routine laboratory testing and subtyping. All A(H7N9) cases detected through the ILI surveillance system by May 15, 2013, were identified by cross-referencing the laboratory-confirmed A(H7N9) line list with the routine sentinel ILI surveillance system. Demographic and epidemiologic data were extracted from field investigation records, and clinical and laboratory data were obtained from medical chart review. Results: Five (3.8%) of a total of 130 laboratory-confirmed influenza A(H7N9) cases reported as of May 28, 2013, were detected through the routine ILI surveillance system. Four (80%) of them were male. Mean age was 13 (range = 2-26) years and none had any underlying medical condition. Exposure history, geographic location and timing of symptom onset were otherwise similar to the general cohort of all laboratory-confirmed cases to date. All patients experienced only mild or moderate disease with an uneventful course of recovery. Among them three (60%) were managed only as outpatients and all quickly recovered after 3-5 days, with nasopharyngeal swabs tested positive for A(H7N9) only after their full recovery. Two patients (40%) were hospitalized for treatment. One was a 4-year-old child from Shanghai who presented initially as an outpatient with fever and mild rhinorrhea to a routine sentinel clinic, and was admitted on the next day for oseltamivir treatment after his nasopharyngeal swab was tested positive for A(H7N9). The other was a 26-year-old man from Jiangsu who presented initially with fever and productive cough to a sentinel clinic, being given ceftazidime without improvement. He was admitted 4 days later with radiologic evidence of left-sided pneumonia, and started on oseltamivir and moxifloxacin. Both remained clinically stable with quick resolution of symptoms within 10 days. Conclusions: Our complete case series of A(H7N9) cases detected through the routine ILI surveillance system provide contrasting clinical presentations to the generally much more severe clinical picture of the majority of laboratory-confirmed A(H7N9) cases detected otherwise. Our findings provide indirect evidence of a substantial proportion of mild disease and support the existence of a “clinical iceberg” phenomenon in influenza A(H7N9) infections. For the clinician, our findings reinforce vigilance to the diverse presentation that can be associated with influenza A(H7N9) virus infections. Our results also suggest that large-scale community surveillance networks can be useful as a population-based sampling tool to enhance understanding of the full spectrum of disease, especially in the early phase of an evolving epidemic.published_or_final_versio

    The Performance of SLNR Beamformers in Multi-User MIMO Systems

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    YesBeamforming in multi-user MIMO (MU-MIMO) systems is a vital part of modern wireless communication systems. Researchers looking for best operational performance normally optimize the problem and then solve for best weight solutions. The weight optimization problem contains variables in numerator and dominator: this leads to so-called variable coupling, making the problem hard to solve. Formulating the optimization in terms of the signal to leakage and noise ratio (SLNR) helps in decoupling the problem variables. In this paper we study the performance of the SLNR with variable numbers of users and handset antennas. The results show that there is an optimum and the capacity curve is a concave over these two parameters. The performances of two further variations of this method are also considered

    Energy and performance trade-off optimization in heterogeneous computing via reinforcement learning

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    This paper suggests an optimisation approach in heterogeneous computing systems to balance energy power consumption and efficiency. The work proposes a power measurement utility for a reinforcement learning (PMU-RL) algorithm to dynamically adjust the resource utilisation of heterogeneous platforms in order to minimise power consumption. A reinforcement learning(RL) technique is applied to analyse and optimise the resource utilisation of field programmable gate array (FPGA) control state capabilities, which is built for a simulation environment with aXilinx ZYNQ multi-processor systems-on-chip (MPSoC) board. In this study, the balance operation mode for improving power consumption and performance is established to dynamically change the programmable logic (PL) end work state. It is based on an RL algorithm that can quickly discover the optimization effect of PL on different workloads to improve energy efficiency. The results demonstrate a substantial reduction of 18% in energy consumption without affecting the application’s performance. Thus, the proposed PMU-RL technique has the potential to be considered for other heterogeneous computing platforms

    Gastric Lavage in Acute Organophosphorus Pesticide poisoning (GLAOP) – a randomised controlled trial of multiple vs. single gastric lavage in unselected acute organophosphorus pesticide poisoning

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    BACKGROUND: Organophosphorus (OP) pesticide poisoning is the most common form of pesticide poisoning in many Asian countries. Guidelines in western countries for management of poisoning indicate that gastric lavage should be performed only if two criteria are met: within one hour of poison ingestion and substantial ingested amount. But the evidence on which these guidelines are based is from medicine overdoses in developed countries and may be irrelevant to OP poisoning in Asia. Chinese clinical experience suggests that OP remains in the stomach for several hours or even days after ingestion. Thus, there may be reasons for doing single or multiple gastric lavages for OP poisoning. There have been no randomised controlled trials (RCTs) to assess this practice of multiple lavages. Since it is currently standard therapy in China, we cannot perform a RCT of no lavage vs. a single lavage vs. multiple lavages. We will compare a single gastric lavage with three gastric lavages as the first stage to assess the role of gastric lavage in OP poisoning. METHODS/DESIGN: We have designed an RCT assessing the effectiveness of multiple gastric lavages in adult OP self-poisoning patients admitted to three Chinese hospitals within 12 hrs of ingestion. Patients will be randomised to standard treatment plus either a single gastric lavage on admission or three gastric lavages at four hour intervals. The primary outcome is in-hospital mortality. Analysis will be on an intention-to-treat basis. On the basis of the historical incidence of OP at the study sites, we expect to enroll 908 patients over three years. This projected sample size provides sufficient power to evaluate the death rate; and a variety of other exposure and outcome variables, including particular OPs and ingestion time. Changes of OP level will be analyzed in order to provide some toxic kinetic data. DISCUSSION: the GLAOP study is a novel, prospective cohort study that will explore to the toxic kinetics of OP and effects of gastric lavage on it. Given the poor information about the impact of gastric lavage on clinical outcomes for OP patients, this study can provide important information to inform clinical practice
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