142 research outputs found

    Method for Trace Oxygen Detection

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    Trace levels of molecular oxygen are measured by introducing a gas containing the molecular oxygen into a target zone, and impacting the molecular oxygen in the target zone with electrons at the O(-) resonant energy level for dissociative electron attachment to produce O(-) ions. Preferably, the electrons have an energy of about 4 to about 10 eV. The amount of O(-) ions produced is measured, and is correlated with the molecular oxygen content in the target zone. The technique is effective for measuring levels of oxygen below 50 ppb. and even less than 1 ppb. The amount of O(-) can be measured in a quadrupole mass analyzer. Best results are obtained when the electrons have an energy of about 6 to about 8 eV. and preferably about 6.8 eV. The method can be used for other species by selecting the appropriate electron energy level

    養龍神話的魔幻化重寫 : 讀也斯 \u3c養龍人師門\u3e

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    在香港,也斯被評為可能是最早譯介當代拉丁美洲小說的譯者,也可能是最早發表帶魔幻色彩的小說的作者。〈養龍人師門〉帶有濃厚的魔幻寫實主義的色彩,業界自然不乏以魔幻寫實主義分析也斯作品,然而似乎只把魔幻寫實視為創作技法,片面理解魔幻寫實主義,忽略其背後的精神。本文嘗試結合學者研究魔幻寫實主義的成果,旁借也斯訪談錄,分析也斯在〈養龍人師門〉如何用魔幻寫實主義重寫神話。本文核心主要是環繞以下兩個問題: 1. 也斯為養龍神話加入/重寫了不少情節和細節,這些故事新質有何意義? 2. 也斯如何以魔幻手法處理重寫,並體驗了怎樣的魔幻寫實主義的特色? 為行文方便,本文將「受魔幻寫實主義影響」、「經過魔幻寫實主義的手 法處理」縮寫成「魔幻化」

    The generic design of a high-traffic advanced metering infrastructure using ZigBee

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    A multi-interface ZigBee building area network (MIZBAN) for a high-traffic advanced metering infrastructure (AMI) for high-rise buildings was developed. This supports meter management functions such as Demand Response for smart grid applications. To cater for the high-traffic communication in these building area networks (BANs), a multi-interface management framework was defined and designed to coordinate the operation between multiple interfaces based on a newly defined tree-based mesh (T-Mesh) ZigBee topology, which supports both mesh and tree routing in a single network. To evaluate MIZBAN, an experiment was set up in a five-floor building. Based on the measured data, simulations were performed to extend the analysis to a 23-floor building. These revealed that MIZBAN yields an improvement in application-layer latency of the backbone and the floor network by 75% and 67%, respectively. This paper provides the design engineer with seven recommendations for a generic MIZBAN design, which will fulfill the requirement for demand response by the U.S. government, i.e. a latency of less than 0.25 s.http://ieeexplore.ieee.org/xpl/RecentIssue.jsp?punumber=9424hb201

    Discordance between Liver Biopsy and FibroScan® in Assessing Liver Fibrosis in Chronic Hepatitis B: Risk Factors and Influence of Necroinflammation

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    BACKGROUND: Few studies have investigated predictors of discordance between liver biopsy (LB) and liver stiffness measurement (LSM) using FibroScan®. We assessed predictors of discordance between LB and LSM in chronic hepatitis B (CHB) and investigated the effects of necroinflammatory activity. METHODS: In total, 150 patients (107 men, 43 women) were prospectively enrolled. Only LSM with ≥ 10 valid measurements was considered reliable. Liver fibrosis was evaluated using the Laennec system. LB specimens <15 mm in length were considered ineligible. Reference cutoff LSM values to determine discordance were calculated from our cohort (6.0 kPa for ≥ F2, 7.5 kPa for ≥ F3, and 9.4 kPa for F4). RESULTS: A discordance, defined as a discordance of at least two stages between LB and LSM, was identified in 21 (14.0%) patients. In multivariate analyses, fibrosis stages F3-4 and F4 showed independent negative associations with discordance (P = 0.002; hazard ratio [HR], 0.073; 95% confidence interval [CI], 0.014-0.390 for F3-4 and P = 0.014; HR, 0.067; 95% CI, 0.008-0.574 for F4). LSM values were not significantly different between maximal activity grades 1-2 and 3-4 in F1 and F2 fibrosis stages, whereas LSM values were significantly higher in maximal activity grade 3-4 than 1-2 in F3 and F4 fibrosis stage (median 8.6 vs. 11.3 kPa in F3, P = 0.049; median 11.9 vs. 19.2 kPa in F4, P = 0.009). CONCLUSION: Advanced fibrosis stage (F3-4) or cirrhosis (F4) showed a negative correlation with discordance between LB and LSM in patients with CHB, and maximal activity grade 3-4 significantly influenced LSM values in F3 and F4

    Reduction of liver stiffness following resolution of acute flares of chronic hepatitis B

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    Background: Measuring liver stiffness is becoming more popular as a non-invasive tool for assessing liver fibrosis. Aim: To assess the effect of severe hepatitis B flare on liver stiffness and determine factors that correlate with liver stiffness measurements. Methods: Twenty-nine patients with severe hepatitis B flare (ALT > 10 × upper limit of normal) were followed up for 1 year. Serial transient elastography was performed at the time of flare, 3-6, and 12 months after flare. Results: At the time of flare, the median liver stiffness was 16.8 kPa, with no patients having normal liver stiffness (<6 kPa). There was a significant decrease in liver stiffness from baseline to 3-6 months (16.8 vs. 7.9 kPa, respectively, P < 0.001), and a further smaller decline from 3-6 to 12 months (7.9 vs. 6.9 kPa, respectively, P = 0.039). By 12 months, 10 (34%) had normalized their liver stiffness. Baseline parameters which correlated with liver stiffness include bilirubin, ALT, albumin, prothrombin time and platelet levels (all P < 0.05). Conclusion: Liver stiffness was increased in patients with severe hepatitis B flares, with return to near normal levels by 6 months. Transient elastography for proper assessment of liver fibrosis should be performed at least 6 months after flare. © 2010 The Author(s).published_or_final_versionSpringer Open Choice, 31 May 201

    Conscious surgery: influence of the environment on patient anxiety

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    Aims: i) To investigate anxiety arising from the experience of the clinical environment during surgery under local/ regional anaesthesia and, ii) to uncover the specific aspects patients find anxiety provoking and possibly dissuade them from opting for such anaesthesia. Background: Operating theatres have historical been designed for safe, efficient surgery on the unconscious patient and not primarily designed for the care of the ‘awake’ patient. However, with the rise in day surgery, the quantity of surgery performed under local/ regional anaesthesia is increasing. Method: As part of a larger study investigating anxiety within modern elective day surgery, adult patients undergoing surgery and local/ regional anaesthesia (n=214) were provided with a questionnaire on the day of surgery for return by mail 24 - 48 hours following surgery. Findings: The experience of being awake, possibly feeling surgeon, seeing body cut open or surgery being more painful were anxiety provoking aspects. Utilising factor analysis ‘intra-operative apprehension’, ‘anaesthetic information provision and ‘health control’ were identified as central features. Moreover, when employing multiple regression, apprehension associated with the intra-operative experience and anaesthetic information provision were significantly associated with an increase in the overall level of anxiety. Conclusions: Although the surrounding clinical environment has previously been a cause of apprehension, the sensations associated with the physical act of surgery on the conscious self appear also to have a considerable influence. Focusing care upon managing patient intra-operative experience and providing anaesthetic information in advance may help limit anxiety and expel the apparent misapprehensions associated with conscious surgery

    The use of transient elastography in the management of chronic hepatitis B

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    There has been increasing interest in noninvasive methods of assessing liver fibrosis over the last decade. The use of transient elastography in measuring liver stiffness has become the forefront of a wide range of noninvasive tools. Most of the other methods are based on measurements of biomarkers associated with fibrosis. There are several reasons for its wide acceptance, including the ease of performing a scan, the short procedure time, the results being immediately available on completion of the examination, and its reproducibility. For chronic hepatitis B (CHB), the cut-off values for F3 and F4 fibrosis range between 7.5–12.0 and 11.0–13.4 kPa, respectively, although the cut-offs may be slightly lower in those with normal ALT. In addition to measuring liver fibrosis, recent studies have demonstrated several other roles for transient elastography, including selecting patients who will benefit from antiviral therapy, monitoring response to antiviral therapy, and predicting long-term outcomes. However, there are limitations associated with transient elastography, including the confounding effects of inflammatory activity, and to a lesser extent, steatosis, on liver stiffness. There is also reduced accuracy observed in lower fibrosis stages (F0–F2). Furthermore, the incidences of failed and unreliable scan have been reported to be ~ 3 and 16%, respectively. Although liver biopsy can be avoided in an estimated 50–60% using transient elastography, in situations where liver stiffness measurement is nondiagnostic or inconsistent with the clinical picture, a biopsy is still recommended. Further studies are needed to consolidate the role of transient elastography in the management of CHB, and for incorporation of this method into current treatment guidelines
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