Browsing by Author "Wang, W."
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Item Enhanced Photosensitized Activity of a BiOCl-Bi₂WO₆ Heterojunction by Effective Interfacial Charge Transfer(2013-10-02) Yang, W.; Ma, B.; Wang, W.; Wen, Y.; Zeng, D.; Shan, BinA BiOCl-Bi₂WO₆ heterojunction with a chemically bonded interface was synthesized via a facile one-step solvothermal method. A series of characterization techniques (XRD, XPS, TEM, SEM, EDS etc.) confirmed the existence of a BiOCl-Bi₂WO₆ interface. The heterojunction yielded a higher photodegradation rate of Rhodamine B under visible light irradiation compared to its individual components. Theoretical studies based on density functional theory calculations indicated that the enhanced photosensitized degradation activity could be attributed to the favorable band offsets across the BiI-O-BiII bonded interface, leading to efficient interfacial charge carrier transfer. Our results reveal the photosensitized mechanism of BiOCl-Bi₂WO₆ heterojunctions and demonstrate their practical use as visible-light-driven photocatalytic materials.Item Field-Aligned and Lattice-Guided Tetrahedral Meshing(John Wiley & Sons Ltd.) Ni, Saifeng; Zhong, Z.; Huang, J.; Wang, W.; Guo, Xiaohu; Ni, Saifeng; Guo, XiaohuWe present a particle-based approach to generate field-aligned tetrahedral meshes, guided by cubic lattices, including BCC and FCC lattices. Given a volumetric domain with an input frame field and a user-specified edge length for the cubic lattice, we optimize a set of particles to form the desired lattice pattern. A Gaussian Hole Kernel associated with each particle is constructed. Minimizing the sum of kernels of all particles encourages the particles to form a desired layout, e.g., field-aligned BCC and FCC. The resulting set of particles can be connected to yield a high quality field-aligned tetrahedral mesh. As demonstrated by experiments and comparisons, the field-aligned and lattice-guided approach can produce higher quality isotropic and anisotropic tetrahedral meshes than state-of-the-art meshing methods.Item P- and S-Decomposition in Anisotropic Media with Localized Low-Rank Approximations(Society of Exploration Geophysicists, 2017-11-13) Wang, W.; Hua, B.; McMechan, George A.; Duquet, B.; 103911551 (McMechan, GA); McMechan, George A.We have developed a P- and S-wave decomposition algorithm based on windowed Fourier transforms and a localized low-rank approximation with improved scalability and efficiency for anisotropic wavefields. The model and wavefield are divided into rectangular blocks that do not have to be geologically constrained; low-rank approximations and P- and S-decomposition are performed separately in each block. An overlap-add method reduces artifacts at block boundaries caused by Fourier transforms at wavefield truncations; limited communication is required between blocks. Localization allows a lower rank to be used than global lowrank approximations while maintaining the same quality of decomposition. The algorithm is scalable, making P- and S-decomposition possible in complicated 3D models. Tests with 2D and 3D synthetic data indicate good P- and S-decomposition results.Item Q-Mat+: An Error-Controllable and Feature-Sensitive Simplification Algorithm for Medial Axis Transform(Elsevier B.V.) Pan, Y.; Wang, B.; Guo, Xiaohu; Zeng, H.; Ma, Y.; Wang, W.; Guo, XiaohuThe medial axis transform (MAT), as an intrinsic shape representation, plays an important role in shape approximation, recognition and retrieval. Q-MAT is a state-of-the-art algorithm driven by quadratic error minimization to compute a geometrically precise, structurally concise, and compact representation of the MAT for 3D shapes. In this work we extend the technique to make it more robust, controllable, and name it Q-MAT+. Combining shape diameter function (SDF) and other mesh information, Q-MAT+ gets a more complete and accurate initial MAT than Q-MAT, even for extreme thin features, such as wires and sheets. Q-MAT+ could quickly remove insignificant branches while preserving significant ones to get a simple and faithful piecewise linear approximation of the MAT. Moreover, it performs the medial axis simplification with explicit maintenance and the control of Hausdorff error, which is not originally supported in Q-MAT. We further demonstrate the outstanding efficiency and accuracy of our method compared with other existing approaches for MAT generation and simplification. ©2019 Elsevier B.V.Item Quantitative liver-specific protein fingerprint in blood: A signature for hepatotoxicity(2014-01-14) Hu, Z.; Lausted, C.; Yoo, Hyuntae; Yan, X.; Brightman, A.; Chen, J.; Wang, W.; Bu, X.; Hood, L.We discuss here a new approach to detecting hepatotoxicity by employing concentration changes of liver-specific blood proteins during disease progression. These proteins are capable of assessing the behaviors of their cognate liver biological networks for toxicity or disease perturbations. Blood biomarkers are highly desirable diagnostics as blood is easily accessible and baths virtually all organs. Fifteen liver-specific blood proteins were identified as markers of acetaminophen (APAP)-induced hepatotoxicity using three proteomic technologies: label-free antibody microarrays, quantitative immunoblotting, and targeted iTRAQ mass spectrometry. Liver-specific blood proteins produced a toxicity signature of eleven elevated and four attenuated blood protein levels. These blood protein perturbations begin to provide a systems view of key mechanistic features of APAP-induced liver injury relating to glutathione and S-adenosyl-L-methionine (SAMe) depletion, mitochondrial dysfunction, and liver responses to the stress. Two markers, elevated membrane- bound catechol-O-methyltransferase (MB-COMT) and attenuated retinol binding protein 4 (RBP4), report hepatic injury significantly earlier than the current gold standard liver biomarker, alanine transaminase (ALT). These biomarkers were perturbed prior to onset of irreversible liver injury. Ideal markers should be applicable for both rodent model studies and human clinical trials. Five of these mouse liver-specific blood markers had human orthologs that were also found to be responsive to human hepatotoxicity. This panel of liver-specific proteins has the potential to effectively identify the early toxicity onset, the nature and extent of liver injury and report on some of the APAP-perturbed liver networks.Item Reverse Time Migrations in Transversely Isotropic Media: A Comparison between Acoustic and Elastic Wave Equations with Two Wave Mode Separation Algorithms(Society of Exploration Geophysicists) Wang, W.; Hua, B.; McMechan, George A.; Williamson, P.; McMechan, George A.Anisotropic reverse time migrations (RTMs) using pseudoacoustic or elastic wave equations are tested, and the migrated PP images, obtained using the same data set as input, are compared. In anisotropic elastic RTMs, both divergence operators, and localized low-rank approximations (LLA), are tested and compared for P/S separation. Tests with synthetic data indicate that elastic RTMs have better illumination apertures than pseudoacoustic RTMs in subsalt areas because of the involvement of converted S-waves in the former. Pseudoacoustic RTMs have diamond-shaped S-wave artifacts, which do not exist in elastic RTM images, provided that the P- and S-waves are separated in the elastic wavefields. LLAs provide affordable, accurate P/S separations in anisotropic media, and the separation results are better than those obtained using divergence operators. Anisotropic elastic RTMs with LLA give the best quality images. ©2019 Society of Exploration Geophysicists.Item The Value of Clinical and Ultrasound Features for the Diagnosis of Infantile Hepatic Hemangioma: Comparison with Contrast-Enhanced CT/MRI(Elsevier Inc.) Xu, M.; Pan, F. -S; Wang, W.; Zhang, X. -E; Li, X. -J; Hong, Yu; Zhou, L. -Y; Xie, X. -Y; Lyu, M. -D; Hong, YuObjectives: To investigate the combined use of ultrasound together with clinical features to differentiate infantile hepatic hemangioma (IHH) from other focal liver lesions (FLLs) in children and to compare the efficacy of the combined method to that of CECT/MRI. Methods: The location, number, size and appearance of the tumors were evaluated in 45 children with IHH. Another 45 children with FLL were randomly selected as a control group. Independent factors for predicting IHH versus FLLs were evaluated. The diagnostic performance of the clinical and ultrasound features was compared with CECT/MRI. Results: Compared with the control FLL group, the IHH group had a younger age at diagnosis (P = 0.008), lower alpha-fetoprotein (AFP) levels (P = 0.000), smaller lesion sizes (P = 0.000), and a higher tumor proportion with a resistance index (RI) of 0.05). Conclusions: CECT/MRI was the effective diagnostic indicator for IHH. However, the combined clinical and ultrasound diagnoses, including age at diagnosis, lesion size, RI and AFP, can achieve the same effectiveness as CECT/MRI. © 2018