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Now showing items 17 - 32 of 67

  • Environmental cooling provided by urban trees under extreme heat and cold waves in U.S. cities

    Wang, Chenghao   Wang, Zhi-Hua   Wang, Chuyuan   Myint, Soe W.  

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  • Interfacing the Urban Land-Atmosphere System Through Coupled Urban Canopy and Atmospheric Models

    Song, Jiyun   Wang, Zhi-Hua  

    We couple a single column model (SCM) to a cutting-edge single-layer urban canopy model (SLUCM) with realistic representation of urban hydrological processes. The land-surface transport of energy and moisture parametrized by the SLUCM provides lower boundary conditions to the overlying atmosphere. The coupled SLUCM-SCM model is tested against field measurements of sensible and latent heat fluxes in the surface layer, as well as vertical profiles of temperature and humidity in the mixed layer under convective conditions. The model is then used to simulate urban land-atmosphere interactions by changing urban geometry, surface albedo, vegetation fraction and aerodynamic roughness. Results show that changes of landscape characteristics have a significant impact on the growth of the boundary layer as well as on the distributions of temperature and humidity in the mixed layer. Overall, the proposed numerical framework provides a useful stand-alone modelling tool, with which the impact of urban land-surface conditions on the local hydrometeorology can be assessed via land-atmosphere interactions.
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  • In-Situ Seed-Mediated High-Yield Synthesis of Copper Nanowires on Large Scale

    Fu, Qi-Qi   Li, Yu-Da   Li, Hui-Hui   Xu, Liang   Wang, Zhi-Hua   Yu, Shu-Hong  

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  • Effects of microwave irradiation on combustion and sodium-release characteristics of Zhundong lignite

    Wang, Zhi-hua   Liu, Yingzu   He, Yong   Whiddon, Ronald   Wan, Kaidi   Xia, Jun   Liu, Jian-zhong  

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  • Enhancing Hydrologic Modelling in the Coupled Weather Research and Forecasting-Urban Modelling System

    Yang, Jiachuan   Wang, Zhi-Hua   Chen, Fei   Miao, Shiguang   Tewari, Mukul   Voogt, James A.   Myint, Soe  

    Urbanization modifies surface energy and water budgets, and has significant impacts on local and regional hydroclimate. In recent decades, a number of urban canopy models have been developed and implemented into the Weather Research and Forecasting (WRF) model to capture urban land-surface processes. Most of these models are inadequate due to the lack of realistic representation of urban hydrological processes. Here, we implement physically-based parametrizations of urban hydrological processes into the single layer urban canopy model in the WRF model. The new single-layer urban canopy model features the integration of, (1) anthropogenic latent heat, (2) urban irrigation, (3) evaporation from paved surfaces, and (4) the urban oasis effect. The new WRF-urban modelling system is evaluated against field measurements for four different cities; results show that the model performance is substantially improved as compared to the current schemes, especially for latent heat flux. In particular, to evaluate the performance of green roofs as an urban heat island mitigation strategy, we integrate in the urban canopy model a multilayer green roof system, enabled by the physical urban hydrological schemes. Simulations show that green roofs are capable of reducing surface temperature and sensible heat flux as well as enhancing building energy efficiency.
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  • Interferon Regulatory Factor 4 Inhibits Neointima Formation by Engaging Kruppel-Like Factor 4 Signaling

    Cheng, Wen-Lin   She, Zhi-Gang   Qin, Juan-Juan   Guo, Jun-Hong   Gong, Fu-Han   Zhang, Peng   Fang, Chun   Tian, Song   Zhu, Xue-Yong   Gong, Jun   Wang, Zhi-Hua   Huang, Zan   Li, Hongliang  

    BACKGROUND: The mechanisms underlying neointima formation remain unclear. Interferon regulatory factors (IRFs), which are key innate immune regulators, play important roles in cardiometabolic diseases. However, the function of IRF4 in arterial restenosis is unknown. METHODS: IRF4 expression was first detected in human and mouse restenotic arteries. Then, the effects of IRF4 on neointima formation were evaluated with universal IRF4-deficient mouse and rat carotid artery injury models. We performed immunostaining to identify IRF4-expressing cells in the lesions. Smooth muscle cell (SMC)-specific IRF4-knockout (KO) and -transgenic (TG) mice were generated to evaluate the effects of SMC-IRF4 on neointima formation. We used microarray, bioinformatics analysis, and chromatin immunoprecipitation assay to identify the downstream signals of IRF4 and to verify the targets in vitro. We compared SMC-IRF4-KO/Kruppel-like factor 4 (KLF4)-TG mice with SMC-IRF4-KO mice and SMC-specific IRF4-TG/KLF4-KO mice with SMC-specific IRF4-TG mice to investigate whether the effect of IRF4 on neointima formation is KLF4-dependent. The effect of IRF4 on SMC phenotype switching was also evaluated. RESULTS: IRF4 expression in both the human and mouse restenotic arteries is eventually downregulated. Universal IRF4 ablation potentiates neointima formation in both mice and rats. Immunostaining indicated that IRF4 was expressed primarily in SMCs in restenotic arteries. After injury, SMC-IRF4-KO mice developed a thicker neointima than control mice. This change was accompanied by increased SMC proliferation and migration. However, SMC-specific IRF4-TG mice exhibited the opposite phenotype, demonstrating that IRF4 exerts protective effects against neointima formation. The mechanistic study indicated that IRF4 promotes KLF4 expression by directly binding to its promoter. Genetic overexpression of KLF4 in SMCs largely reversed the neointima-promoting effect of IRF4 ablation, whereas ablation of KLF4 abolished the protective function of IRF4, indicating that the protective effects of IRF4 against neointima formation are KLF4-dependent. In addition, IRF4 promoted SMC dedifferentiation. CONCLUSIONS: IRF4 protects arteries against neointima formation by promoting the expression of KLF4 by directly binding to its promoter. Our findings suggest that this previously undiscovered IRF4-KLF4 axis plays a key role in vasculoproliferative pathology and may be a promising therapeutic target for the treatment of arterial restenosis.
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  • A simplified genomic subtractive procedure for isolating deleted sequences

    Hou, Ping   Wang, Zhi-Hua   Wang, Xiu-Qin   Wu, Min  

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  • IEEE SSCS DL Zhihua Wang Visits Lehigh Valley Chapter [Chapters]

    Booth, Richard  

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  • Streamflow prediction in ungauged basins by regressive regionalization:a case study in Huai River Basin,China

    Song, Jiyun   Xia, Jun   Zhang, Liping   Wang, Zhi-Hua   Wan, Hui   She, Dunxian  

    Streamflow information is of great significance for flood control, water resources utilization and management, ecological services, etc. Continuous streamflow prediction in ungauged basins remains a challenge, mainly due to data paucity and environmental changes. This study focuses on the modification of a nonlinear hydrological system approach known as the time variant gain model and the development of a regressive method based on the modified approach. This method directly correlates rainfall to runoff through physically based mathematical transformations without requiring additional information of evaporation or soil moisture. Also, it contains parsimonious parameters that can be derived from watershed properties. Both characteristics make this method suitable for practical uses in ungauged basins. The Huai River Basin of China was selected as the study area to test the regressive method. The results show that the proposed methodology provides an effective way to predict streamflow of ungauged basins with reasonable accuracy by incorporating regional watershed information (soil, land use, topography, etc.). This study provides a useful predictive tool for future water resources utilization and management for data-sparse areas or watersheds with environmental changes.
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  • Prognostic significance and mechanisms of patterned matrix vasculogenic mimicry in hepatocellular carcinoma

    Liu, Wen-bin   Xu, Ge-liang   Jia, Wei-dong   Li, Jian-sheng   Ma, Jin-liang   Chen, Ke   Wang, Zhi-hua   Ge, Yong-sheng   Ren, Wei-hua   Yu, Ji-hai   Wang, Wei   Wang, Xiu-jun  

    Vasculogenic mimicry (VM), including tubular VM and patterned matrix VM, has been generally recognized as a new pattern of tumor neovascularization. Pilot studies of tubular VM showed that it was present in hepatocellular carcinoma (HCC) and associated with poor clinical prognosis. However, whether patterned matrix VM is clinically significant in HCC is unknown. To elucidate the effects of patterned matrix VM on prognosis of HCC and the mechanisms involved in VM formation, we examined 151 cases of surgically resected human HCC by immunohistochemistry and transmission electron microscopy and conducted hypoxic experiments on human HCC cell line MHCC97-H. We observed 31 of 151 (20.5%) cases exhibited evidence of patterned matrix VM. The expression of patterned matrix VM was associated with larger tumors (P =3D 0.042), vascular invasion (P =3D 0.016), high-grade HCC (P =3D 0.022), and late-stage HCC (P =3D 0.013). Kaplan-Meier survival analysis revealed that cases of the VM group had lower overall survival (OS) rate (P < 0.001) and disease-free survival (DFS) rate (P =3D 0.002) than that of the non-VM group. Univariate and multivariate analysis indicated that the presence of patterned matrix VM was independent adverse prognostic factor for both OS (P =3D 0.004) and DFS (P =3D 0.011). Expression of hypoxia-inducible factor 1 alpha (HIF-1alpha), matrix metalloproteinase (MMP)-2, and MMP-9 were higher in the VM group than in the non-VM group (P =3D 0.001, P =3D 0.030, P =3D 0.007, respectively). After VM formation was induced by hypoxia, up-regulated expression of HIF-1 alpha, MMP-2, and MMP-9 was also detected in cells cultured under hypoxia condition. Our results indicate that patterned matrix VM exists in HCC, and it might serve as an unfavorable prognostic factor for HCC patients. It is possible that hypoxia via induction of expression of HIF-1alpha, MMP-2, and MMP-9 may enhance VM formation in HCC.
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  • Highly Stimuli-Responsive Au Nanorods/Poly(N-isopropylacrylamide) (PNIPAM) Composite Hydrogel for Smart Switch

    Zhang, Chuan-Ling   Cao, Fu-Hu   Wang, Jin-Long   Yu, Zhi-Long   Ge, Jin   Lu, Yang   Wang, Zhi-Hua   Yu, Shu-Hong  

    To achieve both fast response and structural integrity during the repeating volume changes are the most significant challenges for thermoresponsive hydrogels. In this work, AuNRs/PNIPAM composite hydrogel with fast thermal/optical response and structural integrity is facilely prepared by electrospinning and following a curing treatment. By combining the photothermal property of AuNRs and thermal-responsive effect of PNIPAM, the composite hydrogel shows fast thermal/photoresponse, high heating rate, and high structural integrity with fierce size change. When laser irradiation begins, the temperature of the film increases from room temperature to 34.5 degrees C in 1 s and will further increase even to 60 degrees C in 5 s. Both the porous structure of the hydrogel and the assemble effect of AuNRs within the PNIPAM fibers facilitate the fast responsibility. Furthermore, to take advantage of this fibrous hydrogel adequately, one novel kind of thermal/photocontrolled switch based on the composite hydrogel is prepared, which exhibits fast responsivity and high stability even under acidic or basic conditions.
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  • Green\"s Function Approach for Heat Conduction: Application to Steel Members Protected by Intumescent Paint

    Wang, Zhi-Hua   Tan, Kang Hai  

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  • Temperature Prediction of Concrete-Filled Rectangular Hollow Sections in Fire Using Green’s Function Method.

    Wang, Zhi-Hua   Tan, Kang Hai  

    An efficient numerical approach using the Green鈥檚 function solutions of transient heat conduction for predictions of thermal response inside a concrete-filled rectangular hollow section subjected to fire is proposed in this paper. Thermal properties of construction materials are assumed to be isotropic and homogeneous. The Green鈥檚 function approach adopts different series expansions for small and large time solutions, therefore the desirable convergence properties can be achieved at any range of time by using the time partitioning strategy. A useful analytical relation in terms of step Green鈥檚 functions is derived in this paper to incorporate the multidimensional effect, in particular, for Neumann (prescribed flux) boundary conditions. A modified lumped capacitance method, together with an 鈥渙rthogonal flux鈥?concept, are employed to deal with spatially varying heat flux at the steel鈥揷oncrete interface, where Duhamel鈥檚 theorem is applied in piecewise manner along the interface to incorporate the fire boundary conditions. No spatial discretization is required in the numerical algorithms based on the Green鈥檚 function approach. [ABSTRACT FROM AUTHOR]
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  • Arctigenin Attenuates Ischemia/Reperfusion Induced Ventricular Arrhythmias by Decreasing Oxidative Stress in Rats.

    Yang, Jing   Yin, Hong-Shan   Cao, Ya-Jing   Jiang, Zhi-An   Li, Yong-Jun   Song, Mu-Chun   Wang, Yong-Fei   Wang, Zhi-Hua   Yang, Rong   Jiang, Yun-Fa   Sun, Jin-Peng   Liu, Bo-Yi   Wang, Chuan  

    BACKGROUND/AIMS: Arctigenin (ATG) has been shown to possess anti-inflammatory, immunemodulatory, anti-viral, anti-microbial, anti-carcinogenic, vasodilatory and anti-platelet aggregation properties. However, the protective role of ATG in prevention of arrhythmias induced by myocardial ischemia/reperfusion is unknown. The aim of this study was to investigate the anti-arrhythmia effect of ATG in an ischemia/reperfusion injured rat heart model and explore the related mechanisms.; METHODS: Rats were randomly exposed to sham operation, myocardial ischemia/ reperfusion (MI/R) alone, ATG+ MI/R, pretreated with ATG in low (12.5 mg/kg/day), medium (50 mg/kg/day) and high dose (200 mg/kg/day), respectively. Ventricular arrhythmias were assessed. The activity of superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) and the level of malondialdehyde (MDA) in myocardial tissue were determined by chemical analysis.; RESULTS: Compared to MI/R, rats pretreated with ATG in doses of 50 mg/kg/day and 200 mg/kg/day showed significantly reduced incidence and duration of ventricular fibrillation, ventricular tachycardia and ventricular ectopic beat (VEB), and decreased the arrhythmia score during the 30-min ischemia. Incidence and duration of ventricular tachycardia, infarction size and arrhythmia scores in these groups were significantly decreased during the 120-min reperfusion. No ventricular fibrillation occurred during the period of reperfusion. Rats pretreated with ATG in doses of 50 mg/kg/day and 200 mg/kg/ day markedly enhanced the activities of antioxidant enzymes SOD and GSH-Px, reduced the level of MDA. No differences were observed between the group pretreated with a low dose of ATG and the sham group. Administration of ATG significantly increased the expression of antioxidant stress protein Nrf2, Trx1 and Nox1.; CONCLUSION: Our data suggested that ATG plays anti-arrhythmia role in ischemia/reperfusion injury, which is probably associated with attenuating oxidative stress by Nrf2 signaling pathway. =C2=A9 2018 The Author(s). Published by S. Karger AG, Basel.
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  • Two-Phase Aqueous Extraction of Copper(II) and Its Application to Speciation Analysis of Serum Copper

    Wang, Zhi-Hua   Zeng, Yi   Ma, Hui-Min   Liang, Shu-Chuan  

    The extraction of copper(II) with the two-phase aqueous system isopropyl alcohol–ammonium sulfate–ammonium thiocyanate [i-PrOH–(NH4)2SO4–NH4SCN] was studied and the related experimental conditions were optimized. The results show that Cu(II) can be quantitatively extracted under the selected conditions: 4 ml of i-PrOH, 1 ml of 6 mol/liter sulfuric acid (H2SO4), 1 ml of 2.5 mol/liter NH4SCN, and 5 g of (NH4)2SO4(Vtotal
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  • Antitumoral Activity of Rapamycin Mediated Through Inhibition of HIF-1alpha and VEGF in Hepatocellular Carcinoma

    Wang, Wei   Jia, Wei-Dong   Xu, Ge-Liang   Wang, Zhi-Hua   Li, Jian-Sheng   Ma, Jin-Liang   Ge, Yong-Sheng   Xie, Sheng-Xue   Yu, Ji-Hai  

    Rapamycin (RAPA) inhibits tumor growth and angiogenesis in hepatocellular carcinoma (HCC). The molecular mechanism underlying the antitumoral effects of RAPA remains unclear. Here we established a chemical-induced rat HCC model to investigate the signaling pathways mediating RAPA's antitumor activity. We found that RAPA exposure significantly diminished tumor growth, angiogenesis, and metastasis of HCC. Meanwhile, the antitumor drug dramatically decreased expression of HIF-1alpha and VEGF, either at mRNA or protein levels. Moreover, the low-dose of RAPA (1.5 mg/kg/day) was effective enough to markedly inhibit tumor progression of HCC. The preliminary results suggested that the antitumoral effects of RAPA might be at least partially mediated through downregulation of HIF-1alpha and VEGF, and low-dose RAPA-based regimens exhibited a promising future in treatment of HCC.
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