oalib

Publish in OALib Journal

ISSN: 2333-9721

APC: Only $99

Submit

Any time

2020 ( 2 )

2019 ( 89 )

2018 ( 552 )

2017 ( 525 )

Custom range...

Search Results: 1 - 10 of 43545 matches for " Lu-yue Gai "
All listed articles are free for downloading (OA Articles)
Page 1 /43545
Display every page Item
Diagnostic accuracy of dual-source CT angiography and coronary risk stratification
Xia Yang, Lu-yue Gai, Ping Li, et al
Vascular Health and Risk Management , 2010, DOI: http://dx.doi.org/10.2147/VHRM.S13879
Abstract: gnostic accuracy of dual-source CT angiography and coronary risk stratification Original Research (3689) Total Article Views Authors: Xia Yang, Lu-yue Gai, Ping Li, et al Published Date October 2010 Volume 2010:6 Pages 935 - 941 DOI: http://dx.doi.org/10.2147/VHRM.S13879 Xia Yang1, Lu-yue Gai1, Ping Li1, Yun-dai Chen1, Tao Li2, Li Yang2 1Departments of Cardiology, 2Radiology, Chinese People’s Liberation Army General Hospital, Beijing, China Purpose: The aim of this study was to evaluate the diagnostic accuracy of dual-source computed tomography (DSCT) in coronary artery disease, and to test the possibility of using this technique for coronary risk stratification. Background: With the advent of DSCT, it is possible to image coronary plaque noninvasively. However, the accuracy of this method in terms of sensitivity and specificity has not been determined. Furthermore, noninvasive determination of plaque composition and plaque burden may be important for improving coronary risk stratification. Methods: Forty-six patients with known coronary artery disease underwent DSCT quantitative coronary angiography (QCA), and intravascular ultrasound (IVUS) were included in the study. The sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of DSCT was calculated against QCA and IVUS. Plaque analysis software in a DSCT workstation was used to detect plaque characteristics associated with the Hounsfield unit (Hu) value compared with IVUS. Coronary artery plaques were classified into three types of lesions based on DSCT, and the relationship between different coronary lesions and clinical diagnosis was determined. Results: DSCT angiography was performed in 46 patients, and a diagnostic-quality CT image was obtained in 44 patients. Coronary angiography was performed in 138 vessels and IVUS in 102 vessels of all 46 patients. Sensitivity, specificity, PPV, and NPV of DSCT compared with QCA was 100%, 98%, 92%, and 100%, respectively. The same corresponding index of DSCT compared with IVUS was 100%, 99%, 95%, and 100%, respectively. Quantitative coronary stenosis analysis revealed a good correlation between DSCT and QCA (r = 0.85, P < 0.05, 95% confidence interval [CI] 0.60–0.87). There was also a good correlation between DSCT and IVUS (r = 0.81, P < 0.05, 95% CI 0.56–0.82). In comparison with IVUS, DSCT predicted plaque characteristics more accurately. The coefficient correlation (r) of luminal cross-sectional area and external elastic membrane cross-sectional area between DSCT and IVUS was 0.82 (P < 0.01, CI 0.67–0.89) and 0.78 (P < 0.01, CI 0.67–0.86), respectively. Three different types of plaque were identified on IVUS. Fatty plaque had a 45 ± 14 Hu value, fibrous plaque 90 ± 20, and calcified plaque 530 ± 185, respectively, on DSCT. The relationship between clinical diagnosis and coronary plaque on DSCT indicated that lesions in patients with unstable angina pectoris or ST elevation myocardial infarction were mainly disc
Diagnostic accuracy of dual-source CT angiography and coronary risk stratification
Xia Yang,Lu-yue Gai,Ping Li,et al
Vascular Health and Risk Management , 2010,
Abstract: Xia Yang1, Lu-yue Gai1, Ping Li1, Yun-dai Chen1, Tao Li2, Li Yang21Departments of Cardiology, 2Radiology, Chinese People’s Liberation Army General Hospital, Beijing, ChinaPurpose: The aim of this study was to evaluate the diagnostic accuracy of dual-source computed tomography (DSCT) in coronary artery disease, and to test the possibility of using this technique for coronary risk stratification.Background: With the advent of DSCT, it is possible to image coronary plaque noninvasively. However, the accuracy of this method in terms of sensitivity and specificity has not been determined. Furthermore, noninvasive determination of plaque composition and plaque burden may be important for improving coronary risk stratification.Methods: Forty-six patients with known coronary artery disease underwent DSCT quantitative coronary angiography (QCA), and intravascular ultrasound (IVUS) were included in the study. The sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of DSCT was calculated against QCA and IVUS. Plaque analysis software in a DSCT workstation was used to detect plaque characteristics associated with the Hounsfield unit (Hu) value compared with IVUS. Coronary artery plaques were classified into three types of lesions based on DSCT, and the relationship between different coronary lesions and clinical diagnosis was determined.Results: DSCT angiography was performed in 46 patients, and a diagnostic-quality CT image was obtained in 44 patients. Coronary angiography was performed in 138 vessels and IVUS in 102 vessels of all 46 patients. Sensitivity, specificity, PPV, and NPV of DSCT compared with QCA was 100%, 98%, 92%, and 100%, respectively. The same corresponding index of DSCT compared with IVUS was 100%, 99%, 95%, and 100%, respectively. Quantitative coronary stenosis analysis revealed a good correlation between DSCT and QCA (r = 0.85, P < 0.05, 95% confidence interval [CI] 0.60–0.87). There was also a good correlation between DSCT and IVUS (r = 0.81, P < 0.05, 95% CI 0.56–0.82). In comparison with IVUS, DSCT predicted plaque characteristics more accurately. The coefficient correlation (r) of luminal cross-sectional area and external elastic membrane cross-sectional area between DSCT and IVUS was 0.82 (P < 0.01, CI 0.67–0.89) and 0.78 (P < 0.01, CI 0.67–0.86), respectively. Three different types of plaque were identified on IVUS. Fatty plaque had a 45 ± 14 Hu value, fibrous plaque 90 ± 20, and calcified plaque 530 ± 185, respectively, on DSCT. The relationship between clinical diagnosis and coronary plaque on
The Relationship, Tension and Interaction between Cultural Imperialism and Contra-Flow in Contemporary Media Culture  [PDF]
Yue Lu
Advances in Journalism and Communication (AJC) , 2013, DOI: 10.4236/ajc.2013.14006
Abstract: This study discusses the interaction between cultural imperialism and contra flow in the context of contemporary media culture, mainly looking at the perspective of visual media such as television and movie other than print media. It talks about the relationship between cultural imperialism and dominant flow in global cultural industries. It also explores the relationship between dominant flow and contra-flow and how they influence and challenge each other. Although the wide use of satellite and cable television as well as the increasing use of online communication has enabled the flows of international culture in a multi-national, multi-media and multi-directional movement instead of a one-way model—from the West to the rest of the world, the market share of non-western media content products is still small compared to that of the western media content products. And most globally popular cultural genres are still from the West. Whilst contra-flow may somehow challenge the dominant position of the West in global cultural industries, it is still short of the power to reverse such situation.
A Retrospective Filter Trust Region Algorithm for Unconstrained Optimization  [PDF]
Yue Lu, Zhongwen Chen
Applied Mathematics (AM) , 2010, DOI: 10.4236/am.2010.13022
Abstract: In this paper, we propose a retrospective filter trust region algorithm for unconstrained optimization, which is based on the framework of the retrospective trust region method and associated with the technique of the multi-dimensional filter. The new algorithm gives a good estimation of trust region radius, relaxes the condition of accepting a trial step for the usual trust region methods. Under reasonable assumptions, we analyze the global convergence of the new method and report the preliminary results of numerical tests. We compare the results with those of the basic trust region algorithm, the filter trust region algorithm and the retrospective trust region algorithm, which shows the effectiveness of the new algorithm.
A Novel Improved DSR Algorithm Based on Cross-Layer Mechanism in Wireless Mesh Network
Yue Lu
Journal of Networks , 2010, DOI: 10.4304/jnw.5.7.833-840
Abstract: Routing in Wireless Networks is challenging because of the unpredictable behavior of the medium and the random variations in channel condition. All of these factors lead to poor performance in multi-hop wireless mesh networks specially with the conventional routing. In order to exploit all the advantages that the wireless medium offers, new routing metrics must be explored. These metrics should come from across-layer approach in order to make the routing layer aware of the local issues of the underling layers.In this paper we investigate a new cross-layer routing metric that takes into account available bandwidth as well as the number of retransmissions, thus aiming to minimize end-to-end delay. The experimental results show that the proposed cross-layer metric improves the performance of routing in terms of end-to-end delay and network throughput by selecting paths with high available bandwidth while also avoiding areas of MAC congestion.
A Relatively Optimal Cross-layer Routing Algorithm in Wireless Mesh Network
Yue Lu
Journal of Networks , 2011, DOI: 10.4304/jnw.6.10.1499-1506
Abstract: Routing in Wireless Network is challenging because of the unpredictable behavior of the medium and the proactive effect of interference. All of these factors lead to poor performance in multi-hop wireless mesh networks specially with the conventional routing. In order to exploit all the advantages that the wireless medium offers, new routing metrics must be explored. These metrics should come from across-layer approach in order to make the routing layer aware of the local issues of the underling layers and even change some parameters of the PHY layer. In the paper, we explore three primitive physical layer parameters: bite error rate(BER), interference, and transmission power. We define the metric so that the network layer can correctly find paths that offer: low levels of bite error rate ,reliability in terms of packet success rate, and relatively low power.
Inference for biased models: a quasi-instrumental variable approach
Lu Lin,Lixing Zhu,Yujie Gai
Statistics , 2014,
Abstract: For linear regression models who are not exactly sparse in the sense that the coefficients of the insignificant variables are not exactly zero, the working models obtained by a variable selection are often biased. Even in sparse cases, after a variable selection, when some significant variables are missing, the working models are biased as well. Thus, under such situations, root-n consistent estimation and accurate prediction could not be expected. In this paper, a novel remodelling method is proposed to produce an unbiased model when quasi-instrumental variables are introduced. The root-n estimation consistency and the asymptotic normality can be achieved, and the prediction accuracy can be promoted as well. The performance of the new method is examined through simulation studies.
Estimation and inference for high-dimensional non-sparse models
Lu Lin,Lixing Zhu,Yujie Gai
Statistics , 2011,
Abstract: To successfully work on variable selection, sparse model structure has become a basic assumption for all existing methods. However, this assumption is questionable as it is hard to hold in most of cases and none of existing methods may provide consistent estimation and accurate model prediction in nons-parse scenarios. In this paper, we propose semiparametric re-modeling and inference when the linear regression model under study is possibly non-sparse. After an initial working model is selected by a method such as the Dantzig selector adopted in this paper, we re-construct a globally unbiased semiparametric model by use of suitable instrumental variables and nonparametric adjustment. The newly defined model is identifiable, and the estimator of parameter vector is asymptotically normal. The consistency, together with the re-built model, promotes model prediction. This method naturally works when the model is indeed sparse and thus is of robustness against non-sparseness in certain sense. Simulation studies show that the new approach has, particularly when $p$ is much larger than $n$, significant improvement of estimation and prediction accuracies over the Gaussian Dantzig selector and other classical methods. Even when the model under study is sparse, our method is also comparable to the existing methods designed for sparse models.
Adaptive post-Dantzig estimation and prediction for non-sparse "large $p$ and small $n$" models
Lu Lin,Lixing Zhu,Yujie Gai
Statistics , 2010,
Abstract: For consistency (even oracle properties) of estimation and model prediction, almost all existing methods of variable/feature selection critically depend on sparsity of models. However, for ``large $p$ and small $n$" models sparsity assumption is hard to check and particularly, when this assumption is violated, the consistency of all existing estimations is usually impossible because working models selected by existing methods such as the LASSO and the Dantzig selector are usually biased. To attack this problem, we in this paper propose adaptive post-Dantzig estimation and model prediction. Here the adaptability means that the consistency based on the newly proposed method is adaptive to non-sparsity of model, choice of shrinkage tuning parameter and dimension of predictor vector. The idea is that after a sub-model as a working model is determined by the Dantzig selector, we construct a globally unbiased sub-model by choosing suitable instrumental variables and nonparametric adjustment. The new estimation of the parameters in the sub-model can be of the asymptotic normality. The consistent estimator, together with the selected sub-model and adjusted model, improves model predictions. Simulation studies show that the new approach has the significant improvement of estimation and prediction accuracies over the Gaussian Dantzig selector and other classical methods have.
Self-Construal and Its Implications for Marketing  [PDF]
Kun Gai
Open Journal of Social Sciences (JSS) , 2018, DOI: 10.4236/jss.2018.65020
Abstract:
Self-construal is the concept of the individual’s understanding of the relationship between the self and others. Different self-construals have different effects on the individual’s behavior. This article compares the differences in individual consumption behaviors of individuals with different self construals, and analyzes the cognitive factors that produce such differences. Finally, it provides the application methods of self-construal in marketing practice.
Page 1 /43545
Display every page Item


Home
Copyright © 2008-2017 Open Access Library. All rights reserved.