The Chinese University of Hong Kong

About: The Chinese University of Hong Kong is a education organization based out in Hong Kong, China. It is known for research contribution in the topics: Population & Computer science. The organization has 43411 authors who have published 93672 publications receiving 3066651 citations.

Biventricular Pacing in Patients with Bradycardia and Normal Ejection Fraction

Abstract: Background Observational studies suggest that conventional right ventricular apical pacing may have a deleterious effect on left ventricular function In this study, we examined whether biventricular pacing is superior to right ventricular apical pacing in preventing deterioration of left ventricular systolic function and cardiac remodeling in patients with bradycardia and a normal ejection fraction Methods In this prospective, double-blind, multicenter study, we randomly assigned 177 patients in whom a biventricular pacemaker had been successfully implanted to receive biventricular pacing (89 patients) or right ventricular apical pacing (88 patients) The primary end points were the left ventricular ejection fraction and left ventricular end-systolic volume at 12 months Results At 12 months, the mean left ventricular ejection fraction was significantly lower in the right-ventricular-pacing group than in the biventricular-pacing group (548±91% vs 622±70%, P<0001), with an absolute difference of 74 percentage points, whereas the left ventricular end-systolic volume was significantly higher in the rightventricular-pacing group than in the biventricular-pacing group (357±163 ml vs 276±104 ml, P<0001), with a relative difference between the groups in the change from baseline of 25% (P<0001) The deleterious effect of right ventricular apical pacing occurred in prespecified subgroups, including patients with and patients without preexisting left ventricular diastolic dysfunction Eight patients in the rightventricular-pacing group (9%) and one in the biventricular-pacing group (1%) had ejection fractions of less than 45% (P = 002) There was one death in the right-ventricular-pacing group, and six patients in the right-ventricular-pacing group and five in the biventricular-pacing group were hospitalized for heart failure (P = 074) Conclusions In patients with normal systolic function, conventional right ventricular apical pacing resulted in adverse left ventricular remodeling and in a reduction in the left ventricular ejection fraction; these effects were prevented by biventricular pacing (Centre for Clinical Trials number, CUHK_CCT00037)

Integrin-YAP/TAZ-JNK cascade mediates atheroprotective effect of unidirectional shear flow

Abstract: The Yorkie homologues YAP (Yes-associated protein) and TAZ (transcriptional coactivator with PDZ-binding motif, also known as WWTR1), effectors of the Hippo pathway, have been identified as mediators for mechanical stimuli. However, the role of YAP/TAZ in haemodynamics-induced mechanotransduction and pathogenesis of atherosclerosis remains unclear. Here we show that endothelial YAP/TAZ activity is regulated by different patterns of blood flow, and YAP/TAZ inhibition suppresses inflammation and retards atherogenesis. Atheroprone-disturbed flow increases whereas atheroprotective unidirectional shear stress inhibits YAP/TAZ activity. Unidirectional shear stress activates integrin and promotes integrin-Gα13 interaction, leading to RhoA inhibition and YAP phosphorylation and suppression. YAP/TAZ inhibition suppresses JNK signalling and downregulates pro-inflammatory genes expression, thereby reducing monocyte attachment and infiltration. In vivo endothelial-specific YAP overexpression exacerbates, while CRISPR/Cas9-mediated Yap knockdown in endothelium retards, plaque formation in ApoE-/- mice. We also show several existing anti-atherosclerotic agents such as statins inhibit YAP/TAZ transactivation. On the other hand, simvastatin fails to suppress constitutively active YAP/TAZ-induced pro-inflammatory gene expression in endothelial cells, indicating that YAP/TAZ inhibition could contribute to the anti-inflammatory effect of simvastatin. Furthermore, activation of integrin by oral administration of MnCl2 reduces plaque formation. Taken together, our results indicate that integrin-Gα13-RhoA-YAP pathway holds promise as a novel drug target against atherosclerosis.

Magnetorheological fluid dampers: a review of parametric modelling

Abstract: Due to the inherent nonlinear nature of magnetorheological (MR) dampers, one of the challenging aspects for developing and utilizing these devices to achieve high performance is the development of models that can accurately describe their unique characteristics. In this review, the characteristics of MR dampers are summarized according to the measured responses under different conditions. On these bases, the considerations and methods of the parametric dynamic modelling for MR dampers are given and the state-of-the-art parametric dynamic modelling, identification and validation techniques for MR dampers are reviewed. In the past two decades, the models for MR dampers have been focused on how to improve the modelling accuracy. Although the force–displacement behaviour is well represented by most of the proposed dynamic models for MR dampers, no simple parametric models with high accuracy for MR dampers can be found. In addition, the parametric dynamic models for MR dampers with on-line updating ability and the inverse parametric models for MR dampers are scarcely explored. Moreover, whether one dynamic model for MR dampers can portray the force–displacement and force–velocity behaviour is not only determined by the dynamic model itself but also determined by the identification method.

Unsupervised extraction of visual attention objects in color images

Abstract: This paper proposes a generic model for unsupervised extraction of viewer's attention objects from color images. Without the full semantic understanding of image content, the model formulates the attention objects as a Markov random field (MRF) by integrating computational visual attention mechanisms with attention object growing techniques. Furthermore, we describe the MRF by a Gibbs random field with an energy function. The minimization of the energy function provides a practical way to obtain attention objects. Experimental results on 880 real images and user subjective evaluations by 16 subjects demonstrate the effectiveness of the proposed approach.

Collaborative Web Service QoS Prediction via Neighborhood Integrated Matrix Factorization

Abstract: With the increasing presence and adoption of web services on the World Wide Web, the demand of efficient web service quality evaluation approaches is becoming unprecedentedly strong. To avoid the expensive and time-consuming web service invocations, this paper proposes a collaborative quality-of-service (QoS) prediction approach for web services by taking advantages of the past web service usage experiences of service users. We first apply the concept of user-collaboration for the web service QoS information sharing. Then, based on the collected QoS data, a neighborhood-integrated approach is designed for personalized web service QoS value prediction. To validate our approach, large-scale real-world experiments are conducted, which include 1,974,675 web service invocations from 339 service users on 5,825 real-world web services. The comprehensive experimental studies show that our proposed approach achieves higher prediction accuracy than other approaches. The public release of our web service QoS data set provides valuable real-world data for future research.