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Search Results: 1 - 10 of 81765 matches for " Tian-Xia Yu "
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Insulin-Like Growth Factor-1 as a Prognostic Marker in Patients with Acute Ischemic Stroke
Jian-Hua Tang, Li-Li Ma, Tian-Xia Yu, Juan Zheng, Hui-Juan Zhang, Hui Liang, Peng Shao
PLOS ONE , 2014, DOI: 10.1371/journal.pone.0099186
Abstract: Objective Insulin-like growth factor-1 (IGF-1) has been associated with cardiovascular risk factors and atherosclerosis. The aim of the present study was to evaluate the prognostic value of IGF-1 levels in patients with acute ischemic stroke (AIS). Methods All patients with first-ever AIS from August 1, 2012 to August 31, 2013 were recruited to participate in the study. Clinical data were collected. The National Institutes of Health Stroke Scale (NIHSS) score was assessed on admission blinded to serum IGF-1 levels. For the assessment of functional outcome at 90 days Modified Rankin Scale (mRS) was used. On admission, serum IGF-1 levels were determined by chemiluminescence immunoassay. The influence of IGF-1 levels on functional outcome and death was assessed by multivariate logistic regression analysis. Results Patients with an unfavorable outcomes and non-survivors had significantly decreased serum IGF-1 levels on admission (P<0.0001 for both). IGF-1 was an independent prognostic marker of functional outcome and death [odds ratio 0.89 (0.84–0.93) and 0.90 (0.84–0.95), respectively, P<0.0001 for both, adjusted for age, NIHSS score and other predictors] in patients with ischemic stroke. Serum IGF-1 levels ≤130 ng/mL was as an value indicator for unfavorable functional outcome (OR 3.31, 95% CI:1.87–5.62; P<0.0001), after adjusting for other significant confounders. Conclusions We reported a significant association between low serum IGF-1 levels and unfavorable functional outcome and death.
Vitallium合金在几种日常饮品中的耐腐蚀性能研究
Evaluation on Corrosion Resistance of Vitallium 2000 Plus Co-Cr-Mo Alloy in SeveralDaily Drinks.

陈梦楠,李天侠
CHEN Meng-nan
, LI Tian-xia.

- , 2015,
Abstract: 摘要 目的:研究Vitallium 2000+钴铬钼合金对几种日常饮品的耐腐蚀性。方法:应用电化学工作站及电化学分析仪测绘Vitallium合金在几种日常饮品中的动电位极化曲线,得到自腐蚀电位(Ecorr)、自腐蚀电流密度(Icorr)和极化电阻(Rp), 与对照组人工唾液进行比较分析。场发射扫描电子显微镜(FSEM)观察试样,比较腐蚀前及腐蚀后各组间形貌差异。结果:Vitallium合金在牛奶和弱碱水中, 自Icorr增大,Ecorr和Rp降低,耐腐蚀性能与对照组人工唾液亦有显著性差异(P<0.05);在可乐中Icorr降低,Ecorr和Rp增大,耐腐蚀性能与对照组人工唾液有显著性差异(P<0.05)。结论:牛奶、弱碱水可使Vitallium合金的耐腐蚀性能明显下降
Finite Element Study of the Mechanical Response in Spinal Cord during the Thoracolumbar Burst Fracture
Ya-Bo Yan, Wei Qi, Zi-Xiang Wu, Tian-Xia Qiu, Ee-Chon Teo, Wei Lei
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0041397
Abstract: Background The mechanical response of the spinal cord during burst fracture was seldom quantitatively addressed and only few studies look into the internal strain of the white and grey matters within the spinal cord during thoracolumbar burst fracture (TLBF). The aim of the study is to investigate the mechanical response of the spinal cord during TLBF and correlate the percent canal compromise (PCC) with the strain in the spinal cord. Methodology/Principal Findings A three-dimensional (3D) finite element (FE) model of human T12-L1 spinal cord with visco-elastic property was generated based on the transverse sections images of spinal cord, and the model was validated against published literatures under static uniaxial tension and compression. With the validated model, a TLBF simulation was performed to compute the mechanical strain in the spinal cord with the PCC. Linear regressions between PCC and strain in the spinal cord show that at the initial stage, with the PCC at 20%, and 45%, the corresponding mechanical strains in ventral grey, dorsal grey, ventral white, dorsal white matters were 0.06, 0.04, 0.12, 0.06, and increased to 0.14, 0.12, 0.23, and 0.13, respectively. At the recoiled stage, when the PCC was decreased from 45% to 20%, the corresponding strains were reduced to 0.03, 0.02, 0.04 and 0.03. The strain was correlated well with PCC. Conclusions/Significance The simulation shows that the strain in the spinal cord correlated well with the PCC, and the mechanical strains in the ventral regions are higher than those in the dorsal regions of spinal cord tissue during burst fracture, suggesting that the ventral regions of the spinal cord may susceptible to injury than the dorsal regions.
Examination and evaluation of PCR-based candidate RGA markers in rice
基于PCR的水稻候选RGA标记检验和评估

XIAO Tian-xia,ZHAO Xiang-qian,WANG Xu-sheng,WU Wei-ren,ZHU Jun,
肖天霞
,赵向前,汪旭升,吴为人,朱军

浙江大学学报(农业与生命科学版) , 2007,
Abstract: Based on 402 co-dominant rice candidate RGA markers developed by bioinformatics methods, 40 pairs of primers were randomly selected to test the polymorphisms in rice two subspecies, japonica and indica. The results showed that 87.5% (35 markers) of the total number of markers obtained the clear bands, which 31 markers were co-dominant and 4 markers were dominant. In addition, 31 primer pairs were used to analyze 24 different japonica and indica varieties, and the result showed the markers have good commonality and subspecies-specificity. The averaged Polymorphism Information Content (PIC) of RGA markers was 0.46, indicated that the RGA markers have good polymorphism.
Fuzzy Logic Control Based QoS Management in Wireless Sensor/Actuator Networks
Feng Xia,Wenhong Zhao,Youxian Sun,Yu-Chu Tian
Sensors , 2007, DOI: 10.3390/s7123179
Abstract: Wireless sensor/actuator networks (WSANs) are emerging rapidly as a newgeneration of sensor networks. Despite intensive research in wireless sensor networks(WSNs), limited work has been found in the open literature in the field of WSANs. Inparticular, quality-of-service (QoS) management in WSANs remains an important issue yetto be investigated. As an attempt in this direction, this paper develops a fuzzy logic controlbased QoS management (FLC-QM) scheme for WSANs with constrained resources and indynamic and unpredictable environments. Taking advantage of the feedback controltechnology, this scheme deals with the impact of unpredictable changes in traffic load on theQoS of WSANs. It utilizes a fuzzy logic controller inside each source sensor node to adaptsampling period to the deadline miss ratio associated with data transmission from the sensorto the actuator. The deadline miss ratio is maintained at a pre-determined desired level sothat the required QoS can be achieved. The FLC-QM has the advantages of generality,scalability, and simplicity. Simulation results show that the FLC-QM can provide WSANswith QoS support.
Wireless Sensor/Actuator Network Design for Mobile Control Applications
Feng Xia,Yu-Chu Tian,Yanjun Li,Youxian Sung
Sensors , 2007, DOI: 10.3390/s7102157
Abstract: Wireless sensor/actuator networks (WSANs) are emerging as a new generationof sensor networks. Serving as the backbone of control applications, WSANs will enablean unprecedented degree of distributed and mobile control. However, the unreliability ofwireless communications and the real-time requirements of control applications raise greatchallenges for WSAN design. With emphasis on the reliability issue, this paper presents anapplication-level design methodology for WSANs in mobile control applications. Thesolution is generic in that it is independent of the underlying platforms, environment,control system models, and controller design. To capture the link quality characteristics interms of packet loss rate, experiments are conducted on a real WSAN system. From theexperimental observations, a simple yet efficient method is proposed to deal withunpredictable packet loss on actuator nodes. Trace-based simulations give promisingresults, which demonstrate the effectiveness of the proposed approach.
Fuzzy Logic Control Based QoS Management in Wireless Sensor/Actuator Networks
Feng Xia,Wenhong Zhao,Youxian Sun,Yu-Chu Tian
Computer Science , 2008,
Abstract: Wireless sensor/actuator networks (WSANs) are emerging rapidly as a new generation of sensor networks. Despite intensive research in wireless sensor networks (WSNs), limited work has been found in the open literature in the field of WSANs. In particular, quality-of-service (QoS) management in WSANs remains an important issue yet to be investigated. As an attempt in this direction, this paper develops a fuzzy logic control based QoS management (FLC-QM) scheme for WSANs with constrained resources and in dynamic and unpredictable environments. Taking advantage of the feedback control technology, this scheme deals with the impact of unpredictable changes in traffic load on the QoS of WSANs. It utilizes a fuzzy logic controller inside each source sensor node to adapt sampling period to the deadline miss ratio associated with data transmission from the sensor to the actuator. The deadline miss ratio is maintained at a pre-determined desired level so that the required QoS can be achieved. The FLC-QM has the advantages of generality, scalability, and simplicity. Simulation results show that the FLC-QM can provide WSANs with QoS support.
Wireless Sensor/Actuator Network Design for Mobile Control Applications
Feng Xia,Yu-Chu Tian,Yanjun Li,Youxian Sun
Computer Science , 2008,
Abstract: Wireless sensor/actuator networks (WSANs) are emerging as a new generation of sensor networks. Serving as the backbone of control applications, WSANs will enable an unprecedented degree of distributed and mobile control. However, the unreliability of wireless communications and the real-time requirements of control applications raise great challenges for WSAN design. With emphasis on the reliability issue, this paper presents an application-level design methodology for WSANs in mobile control applications. The solution is generic in that it is independent of the underlying platforms, environment, control system models, and controller design. To capture the link quality characteristics in terms of packet loss rate, experiments are conducted on a real WSAN system. From the experimental observations, a simple yet efficient method is proposed to deal with unpredictable packet loss on actuator nodes. Trace-based simulations give promising results, which demonstrate the effectiveness of the proposed approach.
Control-theoretic dynamic voltage scaling for embedded controllers
Feng Xia,Yu-Chu Tian,Youxian Sun,Jinxiang Dong
Computer Science , 2008,
Abstract: For microprocessors used in real-time embedded systems, minimizing power consumption is difficult due to the timing constraints. Dynamic voltage scaling (DVS) has been incorporated into modern microprocessors as a promising technique for exploring the trade-off between energy consumption and system performance. However, it remains a challenge to realize the potential of DVS in unpredictable environments where the system workload cannot be accurately known. Addressing system-level power-aware design for DVS-enabled embedded controllers, this paper establishes an analytical model for the DVS system that encompasses multiple real-time control tasks. From this model, a feedback control based approach to power management is developed to reduce dynamic power consumption while achieving good application performance. With this approach, the unpredictability and variability of task execution times can be attacked. Thanks to the use of feedback control theory, predictable performance of the DVS system is achieved, which is favorable to real-time applications. Extensive simulations are conducted to evaluate the performance of the proposed approach.
Neural Feedback Scheduling of Real-Time Control Tasks
Feng Xia,Yu-Chu Tian,Youxian Sun,Jinxiang Dong
Computer Science , 2008,
Abstract: Many embedded real-time control systems suffer from resource constraints and dynamic workload variations. Although optimal feedback scheduling schemes are in principle capable of maximizing the overall control performance of multitasking control systems, most of them induce excessively large computational overheads associated with the mathematical optimization routines involved and hence are not directly applicable to practical systems. To optimize the overall control performance while minimizing the overhead of feedback scheduling, this paper proposes an efficient feedback scheduling scheme based on feedforward neural networks. Using the optimal solutions obtained offline by mathematical optimization methods, a back-propagation (BP) neural network is designed to adapt online the sampling periods of concurrent control tasks with respect to changes in computing resource availability. Numerical simulation results show that the proposed scheme can reduce the computational overhead significantly while delivering almost the same overall control performance as compared to optimal feedback scheduling.
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