Browsing by Author "Wang, X"

Now showing 1 - 9 of 9
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    Behavior of Raman modes in InPBi alloys under hydrostatic pressure
    (AIP Advances, 2019-03) Zheng, C; Wang, X; Ning, J; Ding, K; Sun, B; Wang, S; Xu, S
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    Biomimetic hydroxyapatite/collagen composite drives bone niche recapitulation in a rabbit orthotopic model.
    (Materials today. Bio, 2019-03) Minardi, S; Taraballi, F; Cabrera, FJ; Van Eps, J; Wang, X; Gazze, SA; Fernandez-Mourev, Joseph S; Tampieri, A; Francis, L; Weiner, BK; Tasciotti, E
    Synthetic osteoinductive materials that mimic the human osteogenic niche have emerged as ideal candidates to address this area of unmet clinical need. In this study, we evaluated the osteoinductive potential in a rabbit orthotopic model of a magnesium-doped hydroxyapatite/type I collagen ​(MHA/Coll) composite. The composite was fabricated to exhibit a highly fibrous structure of carbonated MHA with 70% (±2.1) porosity and a Ca/P ratio of 1.5 (±0.03) as well as a diverse range of elasticity separated to two distinct stiffness peaks of low (2.35 ​± ​1.16 ​MPa) and higher (9.52 ​± ​2.10 ​MPa) Young's Modulus. Data suggested that these specific compositional and nanomechanical material properties induced the deposition of de novo mineral phase, while modulating the expression of early and late osteogenic marker genes, in a 3D in vitro model using human bone marrow-derived mesenchymal stem cells (hBM-MSCs). When tested in the rabbit orthotopic model, MHA/Col1 scaffold induction of new trabecular bone mass was observed by DynaCT scan, only 2 weeks after implantation. Bone histomorphometry at 6 weeks revealed a significant amount of de novo bone matrix formation. qPCR demonstrated MHA/Coll scaffold full cellularization in vivo and the expression of both osteogenesis-associated genes (Spp1, Sparc, Col1a1, Runx2, Dlx5) as well as hematopoietic (Vcam1, Cd38, Sele, Kdr) and bone marrow stromal cell marker genes (Vim, Itgb1, Alcam). Altogether, these data provide ​evidence of the solid osteoinductive potential of MHA/Coll and its suitability for multiple approaches of bone regeneration.
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    Gene Network Polymorphism Illuminates Loss and Retention of Novel RNAi Silencing Components in the Cryptococcus Pathogenic Species Complex.
    (PLoS Genet, 2016-03) Feretzaki, M; Billmyre, RB; Clancey, SA; Wang, X; Heitman, J
    RNAi is a ubiquitous pathway that serves central functions throughout eukaryotes, including maintenance of genome stability and repression of transposon expression and movement. However, a number of organisms have lost their RNAi pathways, including the model yeast Saccharomyces cerevisiae, the maize pathogen Ustilago maydis, the human pathogen Cryptococcus deuterogattii, and some human parasite pathogens, suggesting there may be adaptive benefits associated with both retention and loss of RNAi. By comparing the RNAi-deficient genome of the Pacific Northwest Outbreak C. deuterogattii strain R265 with the RNAi-proficient genomes of the Cryptococcus pathogenic species complex, we identified a set of conserved genes that were lost in R265 and all other C. deuterogattii isolates examined. Genetic and molecular analyses reveal several of these lost genes play roles in RNAi pathways. Four novel components were examined further. Znf3 (a zinc finger protein) and Qip1 (a homolog of N. crassa Qip) were found to be essential for RNAi, while Cpr2 (a constitutive pheromone receptor) and Fzc28 (a transcription factor) are involved in sex-induced but not mitosis-induced silencing. Our results demonstrate that the mitotic and sex-induced RNAi pathways rely on the same core components, but sex-induced silencing may be a more specific, highly induced variant that involves additional specialized or regulatory components. Our studies further illustrate how gene network polymorphisms involving known components of key cellular pathways can inform identification of novel elements and suggest that RNAi loss may have been a core event in the speciation of C. deuterogattii and possibly contributed to its pathogenic trajectory.
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    Glucose oxidase triggers gelation of N-hydroxyimide-heparin conjugates to form enzyme-responsive hydrogels for cell-specific drug delivery
    (Chemical Science, 2014-11-01) Su, T; Tang, Z; He, H; Li, W; Wang, X; Liao, C; Sun, Y; Wang, Q
    A new strategy for creating enzyme-responsive hydrogels by employing an N-hydroxyimide-heparin conjugate, designed to act as both an enzyme-mediated radical initiator and an enzyme-sensitive therapeutic carrier, is described. A novel enzyme-mediated redox initiation system involving glucose oxidase (GOx), an N-hydroxyimide-heparin conjugate and glucose is reported. The GOx-mediated radical polymerization reaction allows quick formation of hydrogels under mild conditions, with excellent flexibility in the modulation of the physical and chemical characteristics. The heparin-specific enzymatic cleavage reaction enables the delivery of cargo from the hydrogel in amounts that are controlled by the environmental levels of heparanase, which is frequently associated with tumor angiogenesis and metastasis. The formed hydrogels can realize cell-specific drug delivery by targeting cancer cells that are characterized by heparanase overexpression, whilst showing little toxicity towards normal cells. This journal is
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    Impacts of habitat loss on migratory shorebird populations and communities at stopover sites in the Yellow Sea
    (Biological Conservation, 2022-05) Wang, X; Chen, Y; Melville, DS; Choi, CY; Tan, K; Liu, J; Li, J; Zhang, S; Cao, L; Ma, Z
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    Manufacturing Fetishism: The Neo-Mercantilist Preoccupation with Protecting Manufacturing
    (Economic Research Initiatives at Duke (ERID), 2016-12-06) Cassidy, AW; Tower, E; Wang, X
    Two common views are that a country cannot develop without a strong manufacturing base and that trade restrictions are essential to facilitate the development of that strong manufacturing base and thus spur economic growth. We ask: • Does a strong manufacturing share of GDP facilitate economic growth? • Do trade restrictions ensure the development of a strong manufacturing base? • How can governance affect manufacturing share? • And are the relationships we find robust across regions? We find the manufacturing share is not significantly correlated with a higher standard of living. Nor is it related significantly and consistently to economic growth. We also find that trade restrictions both at home and abroad shrink the manufacturing base and smother economic growth. A better way than protectionism and subsidies specific to industry to enhance economic growth is to improve governance effectiveness and the quality of regulation.
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    Modeling the Potential Impacts of Climate Change on the hydrology of selected forested wetlands in the Southeastern United States
    (Hydrology and Earth System Sciences, 2017-10-29) King, JS; Kumar, M; Li, Wenhong; McNulty, SG; Miao, G; Noormets, A; Sun, G; Wang, X; zhang, Y; Zhu, Jie
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    On enrichment strategies for biomarker stratified clinical trials
    (Journal of Biopharmaceutical Statistics, 2017-09-07) Wang, X; Zhou, J; Wang, T; George, SL
    In the era of precision medicine, drugs are increasingly developed to target subgroups of patients with certain biomarkers. In large all-comer trials using a biomarker strati ed design (BSD), the cost of treating and following patients for clinical outcomes may be prohibitive. With a fixed number of randomized patients, the efficiency of testing certain treatments parameters, including the treatment effect among biomarker positive patients and the interaction between treatment and biomarker, can be improved by increasing the proportion of biomarker positives on study, especially when the prevalence rate of biomarker positives is low in the underlying patient population. When the cost of assessing the true biomarker is prohibitive, one can further improve the study efficiency by oversampling biomarker positives with a cheaper auxiliary variable or a surrogate biomarker that correlates with the true biomarker. To improve efficiency and reduce cost, we can adopt an enrichment strategy for both scenarios by concentrating on testing and treating patient subgroups that contain more information about specifi c treatment parameters of primary interest to the investigators. In the first scenario, an enriched biomarker strati ed design (EBSD) enriches the cohort of randomized patients by directly oversampling the relevant patients with the true biomarker, while in the second scenario, an auxiliary-variable-enriched biomarker strati ed design (AEBSD) enriches the randomized cohort based on an inexpensive auxiliary variable, thereby avoiding testing the true biomarker on all screened patients and reducing treatment waiting time. For both designs, we discuss how to choose the optimal enrichment proportion when testing a single hypothesis or two hypotheses simultaneously. At a requisite power, we compare the two new designs with the BSD design in term of the number of randomized patients and the cost of trial under scenarios mimicking real biomarker strati ed trials. The new designs are illustrated with hypothetical examples for designing biomarker-driven cancer trials.
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    Using computer vision on herbarium specimen images to discriminate among closely related horsetails (Equisetum).
    (Applications in plant sciences, 2020-06) Pryer, KM; Tomasi, C; Wang, X; Meineke, EK; Windham, MD
    Premise:Equisetum is a distinctive vascular plant genus with 15 extant species worldwide. Species identification is complicated by morphological plasticity and frequent hybridization events, leading to a disproportionately high number of misidentified specimens. These may be correctly identified by applying appropriate computer vision tools. Methods:We hypothesize that aerial stem nodes can provide enough information to distinguish among Equisetum hyemale, E. laevigatum, and E . ×ferrissii, the latter being a hybrid between the other two. An object detector was trained to find nodes on a given image and to distinguish E. hyemale nodes from those of E. laevigatum. A classifier then took statistics from the detection results and classified the given image into one of the three taxa. Both detector and classifier were trained and tested on expert manually annotated images. Results:In our exploratory test set of 30 images, our detector/classifier combination identified all 10 E. laevigatum images correctly, as well as nine out of 10 E. hyemale images, and eight out of 10 E. ×ferrissii images, for a 90% classification accuracy. Discussion:Our results support the notion that computer vision may help with the identification of herbarium specimens once enough manual annotations become available.