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Bao S.,University of Hong Kong | Zhou X.,Tsinghua University | Zhang L.,Harbin Medical University | Zhou J.,University of Hong Kong | And 6 more authors.
BMC Genomics

Background: The genetic make-up of humans and other mammals (such as mice) affects their resistance to influenza virus infection. Considering the complexity and moral issues associated with experiments on human subjects, we have only acquired partial knowledge regarding the underlying molecular mechanisms. Although influenza resistance in inbred mice has been mapped to several quantitative trait loci (QTLs), which have greatly narrowed down the search for host resistance genes, only few underlying genes have been identified.Results: To prioritize a list of promising candidates for future functional investigation, we applied network-based approaches to leverage the information of known resistance genes and the expression profiles contrasting susceptible and resistant mouse strains. The significance of top-ranked genes was supported by different lines of evidence from independent genetic associations, QTL studies, RNA interference (RNAi) screenings, and gene expression analysis. Further data mining on the prioritized genes revealed the functions of two pathways mediated by tumor necrosis factor (TNF): apoptosis and TNF receptor-2 signaling pathways. We suggested that the delicate balance between TNF's pro-survival and apoptotic effects may affect hosts' conditions after influenza virus infection.Conclusions: This study considerably cuts down the list of candidate genes responsible for host resistance to influenza and proposed novel pathways and mechanisms. Our study also demonstrated the efficacy of network-based methods in prioritizing genes for complex traits. © 2013 Bao et al.; licensee BioMed Central Ltd. Source

Zhang Z.,University of Hong Kong | Zhang Z.,HKU Zhejiang Institute of Research and Innovation HKU ZIRI | Xu M.,Shandong Academy of Sciences | Wang L.,University of Hong Kong | Wang L.,HKU Zhejiang Institute of Research and Innovation HKU ZIRI
Journal of Heat Transfer

The physical vapor transport (PVT) method is widely adopted to produce semiconductor materials including silicon carbide (SiC). This work focuses on the role of thermal radiation for the heat transfer inside the PVT reactor. The radiation is characterized by two dimensionless parameters relating to the SiC charge and to the growth chamber. A simulation program is set up with the finite-volume method (FVM), considering heat generation, conduction, and radiation under the steady-state condition. Comprehensive results are obtained by tuning values of dimensionless parameters and the associated controlling variables, such as the cooling temperature and the coil current density, and illustrated in the phase diagrams. From the study, we find that the charge size has negligible influence on the temperature field, the crucible conduction determines the temperature level, and the relative strength of the chamber radiation against the crucible conduction modifies the temperature field on the SiC ingot. Finally, design guidelines are proposed with the instructive phase diagram to achieve the optimized thermal performance of the PVT reactor. © 2016 by ASME. Source

Yu M.,Shandong Jianzhu University | Fan X.,Shandong Jianzhu University | Walawwe Ranasinghe T.S.B.K.M.,University of Hong Kong | Walawwe Ranasinghe T.S.B.K.M.,HKU Zhejiang Institute of Research and Innovation HKU ZIRI | And 2 more authors.
Advances in Mechanical Engineering

To understand the effects of liquid morphology on the apparent transfer properties of porous media formed by stacked particles, the authors investigate the particles' aggregation state, apparent volume, thermal conductivity, and electrical conductivity of wet stacked glass beads. It shows that the liquid mainly exists as liquid bridges when the liquid content is low and connects each other when high. The transformation of liquid morphology and distribution influences the liquid effects on particles, thus changing the aggregation state of the particles and the apparent properties of the porous media in turn. A model is developed for predicting the critical liquid content at which the liquid morphology shifts from the state of liquid bridges into the state of interconnectedness. The prediction from the model is in good agreement with the experiment. © The Author(s) 2015. Source

Bai C.,University of Hong Kong | Bai C.,HKU Zhejiang Institute of Research and Innovation HKU ZIRI | Wang L.,University of Hong Kong | Wang L.,HKU Zhejiang Institute of Research and Innovation HKU ZIRI
International Journal of Heat and Mass Transfer

The nanofluid configuration is critical for the system performance. Particle material can be configured as dispersed or blade configuration inside the base fluid. This work compares the performance of these two configurations for five heat-conduction systems. The first two systems are heat-transferring and use nanofluids with higher-conductivity particles. The other three systems are heat-insulating and employ nanofluids with lower-conductivity particles. Homogeneous nanofluids with the thermal conductivity of Hashin-Shtrikman bounds are assumed for the dispersed configurations. One single-blade is assumed for the blade configuration. Within the parameter range examined, the performance superiority depends on the system aspect ratio for the heat-transferring systems. For the three heat-insulating systems, the blade configuration always performs better than the dispersed configuration. © 2013 Elsevier Ltd. All rights reserved. Source

Kong T.,University of Hong Kong | Kong T.,HKU Zhejiang Institute of Research and Innovation HKU ZIRI | Wang L.,University of Hong Kong | Wang L.,HKU Zhejiang Institute of Research and Innovation HKU ZIRI | And 3 more authors.
Soft Matter

In this work, we have developed a facile, economical microfluidic approach as well as a simple model description to measure and predict the mechanical properties of composite core-shell microparticles made from materials with dramatically different elastic properties. By forcing the particles through a tapered capillary and analyzing their deformation, the shear and compressive moduli can be measured in one single experiment. We have also formulated theoretical models that accurately capture the moduli of the microparticles in both the elastic and the non-linear deformation regimes. Our results show how the moduli of these core-shell structures depend on the material composition of the core-shell microparticles, as well as on their microstructures. The proposed technique and the understanding enabled by it also provide valuable insights into the mechanical behavior of analogous biomaterials, such as liposomes and cells. © 2014 the Partner Organisations. Source

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