49 results on '"Yunxia Xu"'
Search Results
2. Joint elastic reverse time migration of towed streamer and sparse ocean-bottom seismic node hybrid data
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Pengfei Yu, Mingzhi Chu, Yunxia Xu, Baojin Zhang, and Jianhua Geng
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Geophysics ,Geochemistry and Petrology - Abstract
Compared to 1C towed-streamer (TS) seismic exploration, 4C ocean-bottom seismic (OBS) node exploration has great advantages in complex structure imaging, lithology, and fluid identification using elastic waves. However, sparse spatial sampling of OBS node surveys highlights the problems of the imaging acquisition footprint, poor phase continuity, and low signal-to-noise ratio (S/N) with conventional elastic reverse time migration (ERTM) methods. Therefore, a solution of joint ERTM (J-ERTM) is proposed by combining sparse OBS node data with dense TS data. In the J-ERTM of the hybrid data, a novel weighted boundary condition combined with acoustic-elastic coupling equations and a vector-based crosscorrelation imaging condition are presented to perform PP and PS imaging by receiver-side tensorial extrapolation of TS and OBS node hybrid data. A synthetic example demonstrates that our method can effectively process TS and OBS node hybrid data and improve elastic imaging problems caused by OBS node sparse acquisition. J-ERTM techniques also are applied to an active-source OBS data set from the South China Sea. To improve the imaging quality with limited data, some preprocessing procedures for field TS and OBS node hybrid data sets are necessary, such as denoising, OBS node relocation, OBS node orientation correction, OBS node calibration, and others. After preprocessing, the pressure component and velocity components have a more physical energy relationship, more consistent frequency range and wavelet, and a higher S/N. Finally, the preprocessed hybrid data can be used for J-ERTM. The imaging results demonstrate that our method works well with field data.
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- 2023
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3. Hypergraph Regularized Lp Smooth Nonnegative Matrix Factorization for Data Representation
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Yunxia Xu, Linzhang Lu, Qilong Liu, and Zhen Chen
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Nonnegative matrix factorization (NMF) has been shown to be a strong data representation technique, with applications in text mining, pattern recognition, image processing, clustering and other fields. In this paper, we propose a hypergraph regularized Lp smooth nonnegative matrix factorization (HGSNMF), by incorporating hypergraph regularization and Lp smoothing constraint terms into the standard NMF. The hypergraph regularization term can capture the intrinsic geometry structure of the high dimension space data more comprehensively than simple graph, the Lp smoothing constraint may yield a smooth and more accurate solution to the optimization problem. The updating rules are given using multiplicative update techniques, and the convergence of HGSNMF is theoretically investigated. The experimental results on four different data sets show that the proposed method has better clustering effect than the related state-of-the-art methods in the vast majority of cases.
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- 2023
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4. Cryo-EM structures of human monkeypox viral replication complexes with and without DNA duplex
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Yunxia Xu, Yaqi Wu, Yuanyuan Zhang, Ruixin Fan, Yaxue Yang, Danyang Li, Shimin Zhu, Biao Yang, Zhengyu Zhang, and Changjiang Dong
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Cell Biology ,Molecular Biology - Published
- 2023
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5. Repurposing clinically approved drugs for COVID-19 treatment targeting SARS-CoV-2 papain-like protease
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Jinle Tang, Yi Zheng, Lipei Fang, Juanli Pan, Yaoqi Zhou, Yunxia Xu, Wei Xu, Yanhong Ma, Jian Zhan, Yingshou Lei, Danting Zhang, Xin Chen, Ke Chen, and Bao Zhang
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medicine.medical_treatment ,Chloroxine ,Coronavirus Papain-Like Proteases ,Molecular Dynamics Simulation ,Pharmacology ,Antiviral Agents ,Biochemistry ,Molecular Docking Simulation ,Article ,Chloroquinolinols ,chemistry.chemical_compound ,Docking (dog) ,Ubiquitin ,Structural Biology ,medicine ,Humans ,Molecular Biology ,Repurposing ,Binding Sites ,Protease ,biology ,SARS-CoV-2 ,business.industry ,Tanshinone IIA sulfonate sodium ,Drug Repositioning ,General Medicine ,Phenanthrenes ,Papain-like protease ,High-Throughput Screening Assays ,COVID-19 Drug Treatment ,Drug repositioning ,Papain ,Coronavirus Protease Inhibitors ,chemistry ,biology.protein ,Viral genome replication ,business - Abstract
COVID-19 is a disease caused by SARS-CoV-2, which has led to more than 4 million deaths worldwide. As a result, there is a worldwide effort to develop specific drugs for targeting COVID-19. Papain-like protease (PLpro) is an attractive drug target because it has multiple essential functions involved in processing viral proteins, including viral genome replication and removal of post-translational ubiquitination modifications. Here, we established two assays for screening PLpro inhibitors according to protease and anti-ISGylation activities, respectively. Application of the two screening techniques to the library of clinically approved drugs led to the discovery of tanshinone IIA sulfonate sodium and chloroxine with their IC50 values of lower than 10 μM. These two compounds were found to directly interact with PLpro and their molecular mechanisms of binding were illustrated by docking and molecular dynamics simulations. The results highlight the usefulness of the two developed screening techniques for locating PLpro inhibitors.
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- 2021
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6. Seismic imaging of a seepage gas hydrate system with a harrow-like acquisition geometry
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Bin Liu, Yunxia Xu, Hua Xue, Pengfei Wen, and Dajiang Meng
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Geophysics - Published
- 2022
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7. Proteomics analysis reveals novel insights into the mechanism of hepatotoxicity induced by Tripterygium wilfordii multiglycoside in mice
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Yingying Miao, Qin Zhang, Zihang Yuan, Jie Wang, Yunxia Xu, Yuanyuan Chai, Min Du, Qinwei Yu, Luyong Zhang, and Zhenzhou Jiang
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Pharmacology ,Pharmacology (medical) - Abstract
Tripterygium wilfordiimultiglycoside (GTW), extracted and purified from the peeled roots ofT. wilfordiiHook.f. (TwHF), is a well-known traditional Chinese medicine and applied to various autoimmune diseases clinically. However, it has been reported to cause severe liver injury. At present, the mechanism underlying GTW-induced hepatotoxicity remain poorly defined. Here, we evaluated the effects of GTW on mouse liver and elucidated the associated mechanismsvialabel-free proteomics combined with bioinformatics analysis. Male C57BL/6J mice were randomly divided into normal group, a low-dose GTW (70 mg/kg) group and a high-dose GTW (140 mg/kg) group. After 1-week administration, GTW dose-dependently induced hepatotoxicity. Further analysis showed that GTW could act on the intestinal immune network for IgA production pathway, which plays an important role in maintaining intestinal homeostasis and influences the crosstalk between gut and liver. Western blots confirmed that GTW could decrease pIgR protein expression in the liver and ileum, and, as a result, the secretion of IgA into gut lumen was reduced. Further validation showed that intestinal barrier integrity was impaired in GTW-treated mice, promoting bacteria transferring to the liver and triggering proinflammatory response. Our study demonstrated that gut-liver axis may play a vital part in the progression of GTW-induced hepatotoxicity, which provides guidance for basic research and clinical application of GTW.
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- 2022
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8. Investigating Derivatives of Tanshinone IIA Sulfonate Sodium and Chloroxine for Their Inhibition Activities against the SARS-CoV-2 Papain-like Protease
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Xin Chen, Ke Chen, Zhaoyong Zhang, Peilan Wei, Lu Zhang, Yunxia Xu, Qili Lun, Yanhong Ma, Fang Wu, Ying Zhang, Yanqun Wang, Jincun Zhao, Yaoqi Zhou, Jian Zhan, and Wei Xu
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General Chemical Engineering ,General Chemistry - Abstract
SARS-CoV-2 has caused a global pandemic of COVID-19, posing a huge threat to public health. The SARS-CoV-2 papain-like cysteine protease (PLpro) plays a significant role in virus replication and host immune regulation, which is a promising antiviral drug target. Several potential inhibitors have been identified in vitro. However, the detailed mechanism of action and structure-activity relationship require further studies. Here, we investigated the structure-activity relationships of the series of derivatives of tanshinone IIA sulfonate sodium (TSS) and chloroxine based on biochemical analysis and molecular dynamics simulation. We found that compound
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- 2022
9. Proteomics analysis reveals novel insights into the mechanism of hepatotoxicity induced by
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Yingying, Miao, Qin, Zhang, Zihang, Yuan, Jie, Wang, Yunxia, Xu, Yuanyuan, Chai, Min, Du, Qinwei, Yu, Luyong, Zhang, and Zhenzhou, Jiang
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- 2022
10. Glycocholic acid aggravates liver fibrosis by promoting the up-regulation of connective tissue growth factor in hepatocytes
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Zihang Yuan, Jie Wang, Haoran Zhang, Yuanyuan Chai, Yunxia Xu, Yingying Miao, Ziqiao Yuan, Luyong Zhang, Zhenzhou Jiang, and Qinwei Yu
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Liver Cirrhosis ,Bile Acids and Salts ,Mice ,Liver ,Connective Tissue Growth Factor ,Hepatocytes ,Hepatic Stellate Cells ,Animals ,YAP-Signaling Proteins ,Cell Biology ,Glycocholic Acid ,Rats ,Up-Regulation - Abstract
The precise role of bile acid in the progression of liver fibrosis has yet to be elucidated. In this study, common bile duct ligation was used as an in vivo mouse model for the evaluation of bile acids that promote liver connective tissue growth factor expression.Primary rat and mice hepatocytes, as well as primary rat hepatic stellate and HepaRG cells were evaluated as in vitro models for promoting the expression of connective tissue growth factor by bile acids.Compared with taurochenodeoxycholic acid, glycochenodeoxycholic acid, and taurocholic acid, glycocholic acid (GCA) most strongly promoted the secretion of connective tissue growth factor in mouse primary hepatocytes, rat primary hepatocytes and HepaRGs. GCA did not directly promote the activation of hepatic stellate cells. The administration of GCA in mice with ligated bile ducts promotes the progression of liver fibrosis, which may promote the yes-associated protein of hepatocytes into the nucleus, resulting in the hepatocytes secreting more connective tissue growth factor for hepatic stellate cell activation. In conclusion, our data showed that GCA can induce the expression of connective tissue growth factor in hepatocytes by promoting the nuclear translocation of yes-associated protein, thereby activating hepatic stellate cells.Our findings help to elucidate the contribution of GCA to the progression of hepatic fibrosis in cholestatic disease and aid the clinical monitoring of cholestatic liver fibrosis development.
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- 2022
11. Novel application of anti-human Fc nanobody for screening high-producing CHO cells for monoclonal antibody
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Di Zhu, Zheng Wang, Yunxia Xu, Jing Lin, Mei Qiu, Jianghai Liu, and Xinlei Li
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Environmental Engineering ,Bioengineering ,Biotechnology - Abstract
Animal-derived anti-IgG secondary antibodies are currently employed to stain and screen of human monoclonal antibody(mAb)-producing cells, but using animal-derived antibodies may raise the concerns of high cost, complicated operations and biological safety issues in biopharmaceutical manufacturing. Nanobodies(VHHs) are attractive forms of antibodies for their straightforward engineering and expression in both eukaryotic and prokaryotic systems. Using phage-displayed immune llama VHH library, we identified new anti-Fc VHHs that could bind to human Fc with high affinity. In GFP fusion format, the anti-Fc VHH-GFP generated dramatically stronger FACS signals than AF488 conjugated anti-IgG antibodies when used for staining mAb-producing CHO cells. Furthermore, preparative sorting of CHO cells based on anti-Fc VHH-GFP staining resulted in the enrichment of cell lines capable of synthesizing mAb at high productivity. This safe and cost-efficient anti-Fc VHH-GFP may optimize the process of generating highly productive cell lines for therapeutic mAb production compared to conventional animal-derived fluorescent antibodies.
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- 2022
12. Preparation and properties of
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Yu, Yi, Ting, Huang, Yunxia, Xu, Jianfeng, Mei, Yanlu, Zhang, Xudong, Wang, Jianshu, Chen, and Guoqing, Ying
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Chitosan ,Ofloxacin ,Polyvinyl Alcohol ,Animals ,Hydrogels ,Rabbits ,Bandages - Abstract
Chitosan and its derivatives show potent biocompatibility, biodegradability, antimicrobial activity, hemostatic effects, and wound healing properties. Their application in wound dressings has garnered substantial research interest. In this work, we prepared a drug-loaded hydrogel by mixing
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- 2022
13. Effects of Ambidextrous Leadership on Employees’ Work Behavior: The Mediating Role of Psychological Empowerment
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Li, Wang, Yuchen, Sun, Jinzhi, Li, Yunxia, Xu, Meifen, Chen, Xiaoyu, Zhu, and Dawei, Wang
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General Psychology - Abstract
The complexity of today’s organizational environment increasingly requires leaders to think in a dynamic and flexible way to resolve contradictory issues. This study explored and compared the effects of servant leadership and authoritarian leadership on employees’ work behavior from the perspectives of ambidextrous leadership theory and social exchange theory, and further examined the mediating role of psychological empowerment. In this study, 315 employees from state-owned communication companies in Shandong and Zhejiang Provinces in China were selected as subjects, and path analysis was used to test the hypotheses. The results showed that servant leadership positively predicted organizational citizenship behavior and task performance. While authoritarian leadership negatively predicted organizational citizenship behavior and positively predicted task performance, psychological empowerment mediated the relationship between the two leadership styles and organizational citizenship behavior and task performance. Moreover, psychological empowerment and organizational citizenship behavior played a multiple mediating role between the two leadership styles and task performance. The theoretical implications of these findings for advancing the ambidextrous leadership theory in Chinese organizational contexts and practical approaches for corporate managers to effectively use ambidextrous leadership style were discussed.
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- 2022
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14. Interface engineering of microelectrodes toward ultrasensitive monitoring of β-amyloid peptides in cerebrospinal fluid in Alzheimer's disease
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Guoyue Shi, Hui Gu, Anwei Zhu, Yunxia Xu, Shushu Ding, and Qi Liu
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Male ,Cations, Divalent ,Metal Nanoparticles ,Peptide ,02 engineering and technology ,010402 general chemistry ,01 natural sciences ,Biochemistry ,Silver nanoparticle ,Analytical Chemistry ,Mice ,chemistry.chemical_compound ,Cerebrospinal fluid ,Alzheimer Disease ,β amyloid ,Electrochemistry ,Animals ,Humans ,Environmental Chemistry ,Spectroscopy ,chemistry.chemical_classification ,Detection limit ,Amyloid beta-Peptides ,Interface engineering ,Electrochemical Techniques ,021001 nanoscience & nanotechnology ,0104 chemical sciences ,Mice, Inbred C57BL ,Microelectrode ,Monomer ,chemistry ,Biophysics ,Hemin ,Gold ,0210 nano-technology ,Microelectrodes ,Copper - Abstract
Ultrasensitive detection of monomeric β-amyloid peptides is of fundamental significance for studying the pathological progression of Alzheimer's disease (AD). In this article, by facilely engineering a gold microelectrode interface, we developed a novel electrochemical biosensor for sensitive and selective monitoring of β-amyloid peptide (Aβ) monomers in cerebrospinal fluid (CSF). Through specific Cu2+-Aβ-hemin coordination, Aβ directed the assembly of Cu2+-PEI/AuNPs-hemin nanoprobes into network aggregates on a microelectrode interface, which promoted the enrichment of Aβ monomers on the microelectrode. Furthermore, the AuNP aggregate promotes the deposition of silver nanoparticles, which were utilized for the electrochemical stripping analysis of the Aβ monomer. The proposed method displayed ultra-sensitivity for Aβ monomers with the detection limit down to 0.2 pM. Besides, high selectivity toward Aβ monomers was observed. These remarkable analytical performances render the electrochemical biosensor useful for evaluating the dynamic change of Aβ monomer level in CSF of live mice with AD, promoting the investigation of the role that Aβ monomers play in brain events.
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- 2020
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15. Obeticholic acid aggravates liver injury by up-regulating the liver expression of osteopontin in obstructive cholestasis
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Jie, Wang, Zihang, Yuan, Haoran, Zhang, Qipeng, Wu, Yingying, Miao, Yunxia, Xu, Qinwei, Yu, Xiaofei, Huang, Ziling, Zhang, Xinliang, Huang, Qianhui, Tang, Luyong, Zhang, and Zhenzhou, Jiang
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Hydroxyproline ,Mice ,Cholestasis ,Liver ,Animals ,Osteopontin ,General Medicine ,General Pharmacology, Toxicology and Pharmaceutics ,Alkaline Phosphatase ,Chenodeoxycholic Acid ,Fibrosis ,General Biochemistry, Genetics and Molecular Biology - Abstract
Obeticholic acid (OCA) was approved for the treatment of primary biliary cholangitis (PBC) patients, as it can significantly improve the level of serum alkaline phosphatase. However, OCA-induced liver injury in PBC patients puts them at risk of acute chronic liver failure, thus limiting the clinical application of OCA. Osteopontin (OPN), an extracellular cell matrix molecule, is highly induced in many cholestatic liver diseases. Herein we explored whether liver injury exacerbation by OCA was related to OPN.Bile duct ligation (BDL) mice were treated with OCA (40 mg/kg) to evaluate its effect on liver injury and OPN involvement. Enzyme-linked immunosorbent assay, western blot, immunohistochemistry, and other assays were used to detect OPN levels in serum and liver. Immunohistochemistry, and immunofluorescence, among other assays, were used to evaluate the extent of ductular reaction. The extent of fibrosis was also determined using various assays, such as immunohistochemistry, quantitative real-time PCR (qPCR), and hydroxyproline assays.OPN was overexpressed in the liver of BDL mice treated with OCA. OCA induced overexpression of OPN exacerbated ductular reaction, fibrosis, and liver inflammation, and reduced hepatocyte proliferation.Upon liver injury, OCA upregulates the expression of OPN in the liver and accelerates disease progression. This mechanism helps explain the risk of liver damage associated with OCA.
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- 2022
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16. Enantiomers of Single Chirality Nanotube as Chiral Recognition Interface for Enhanced Electrochemical Chiral Analysis
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Yunxia Xu, Chunling Pu, Anwei Zhu, Guoyue Shi, and Qi Liu
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Nanotube ,Chemistry ,010401 analytical chemistry ,Carbon nanotube ,010402 general chemistry ,Electrochemistry ,01 natural sciences ,0104 chemical sciences ,Analytical Chemistry ,Electrochemical gas sensor ,law.invention ,law ,Electrode ,Physical chemistry ,Enantiomer ,Enantiomeric excess ,Chirality (chemistry) - Abstract
Although separation of single-walled carbon nanotubes (SWCNTs) according to their helicity and handedness has been attracting tremendous interest recently, exploration of the left- and right-handed SWCNT enantiomers (defined as "M" and "P") to chiral sensing still remains in the early stage. Here we presented a new electrochemical sensor for chiral discrimination, which for the first time amplified the chiral selection on the electrode surface based on the left- or right-handed semiconducting SWCNT enantiomers with (6,5)-enriched chirality. The enantioselectivity was demonstrated by different peak current response to analyte enantiomers, observed in differential pulse voltammogram (DPV). Chiral distinguishing might be a result of the formation of an efficient chiral nanospace originating from the high purity of single enantiomer of (6,5) SWCNT. The obtained chiral electrodes were also applied to determine the enantiomeric excess (ee) of DOPA. There was a good linear relationship between DPV peak currents and % ee of l-DOPA. This study is the first example showing how the structure of chiral SWCNTs influences electrochemical chiral recognition.
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- 2019
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17. A complex gas hydrate system imaged jointly using MCS and OBS data from the northern South China Sea
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Wen Pengfei, Yunxia Xu, Liqing Li, Xiangchun Wang, Bin Liu, and Heng Zhang
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South china ,Clathrate hydrate ,Drilling ,010502 geochemistry & geophysics ,Oceanography ,01 natural sciences ,Arrival time ,Seafloor spreading ,Geophysics ,Geochemistry and Petrology ,Offshore geotechnical engineering ,Refraction (sound) ,Tomography ,Seismology ,Geology ,0105 earth and related environmental sciences - Abstract
Much of our knowledge of gas hydrate in the Dongsha area of the South China Sea has been gained through intensive geophysical surveys and drilling. However, many factors remain unclear, such as the co-existence of shallow gas hydrate and deeper gas hydrate. This lack of clarity is partially due to the lack of a depth-domain velocity model and accurate imagery of the gas hydrate-bearing sediments. In this study, pre-stack depth migration (PSDM) is used to produce subsurface images using a depth-domain velocity model from OBS tomography as the migration velocity. A simple initial velocity model was built using the seafloor depth information derived from multi-channel seismic (MCS) data. This simple model was used to build a more accurate velocity model by using first arrival time tomography from OBS data. Three different approaches were used to assess the reliability of the velocity model. Resolution tests and uncertainties analysis were used to further evaluate the model. The final PSDM image revealed some features more clearly than they were seen on the time migration image. These features help better explain the complex gas hydrate system. The depth of a bottom-simulating reflector (BSR) was picked directly from the PSDM image. This BSR is very consistent with the drilling result. Our work highlights the importance of PSDM in the study of gas hydrate in complex settings and highlights the potential and value of using OBS refraction in building shallow velocity models.
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- 2020
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18. Preparation and properties of N-glycosylated chitosan/polyvinyl alcohol hydrogels for use in wound dressings
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Yu Yi, Ting Huang, Yunxia Xu, Jianfeng Mei, Yanlu Zhang, Xudong Wang, Jianshu Chen, and Guoqing Ying
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Biomaterials ,Biomedical Engineering ,Biophysics ,Bioengineering ,General Medicine - Abstract
Chitosan and its derivatives show potent biocompatibility, biodegradability, antimicrobial activity, hemostatic effects, and wound healing properties. Their application in wound dressings has garnered substantial research interest. In this work, we prepared a drug-loaded hydrogel by mixing N-glycosylated chitosan with polyvinyl alcohol (PVA), followed by loading of ofloxacin. A 2:1 volume ratio of chitosan to PVA was found to be optimal based on swelling and water evaporation rates. The slow-drug-release performance of the blended hydrogel was best when the ofloxacin loading was 5.0%. The ofloxacin-loaded hydrogel shows excellent antimicrobial properties in vitro and wound healing ability in an in vivo rabbit full-thickness excision wound model. The chitosan/PVA blended hydrogel has great potential for use in wound dressings and sustained drug release.
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- 2022
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19. Study on the effects of Zhuanggu Guanjie Pill, a modern Chinese medicine formula, on the activities and mRNA expression of seven CYP isozymes in rats
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Ziyin Xia, Yunxia Xu, Xin Huang, Luyong Zhang, Yuanyuan Chai, and Zhenzhou Jiang
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Male ,medicine.medical_specialty ,CYP2B6 ,CYP3A ,Herb-Drug Interactions ,Cmax ,Receptors, Cytoplasmic and Nuclear ,Calcitriol receptor ,Cytochrome P-450 Enzyme System ,Pharmacokinetics ,Internal medicine ,Drug Discovery ,Constitutive androstane receptor ,medicine ,Animals ,RNA, Messenger ,Medicine, Chinese Traditional ,Rats, Wistar ,Cytochrome P-450 Enzyme Inducers ,Pharmacology ,biology ,CYP1A2 ,Cytochrome P450 ,Isoenzymes ,Endocrinology ,biology.protein ,Female ,Drugs, Chinese Herbal - Abstract
Ethnopharmacological relevance Zhuanggu Guanjie Pill (ZGGJP), a modern Chinese medicine formula, is composed of 12 herbs and has been used to treat osteoporosis in China for almost 30 years. However, no in vivo study of the influences of ZGGJP on the cytochrome P450 (CYP) activities have been reported. Aim of the study The aim of this study was to evaluate the effects of ZGGJP on the activities and the mRNA expression of CYP enzymes (CYP1A2, CYP2B6, CYP2C9, CYP2C19, CYP2D6, CYP2E1 and CYP3A) and their corresponding nuclear receptor levels in rats. Materials and methods After 7 days oral treatment of ZGGJP at low- and high-dose, cocktail solution was given to rats. Blood samples were collected at series of time points. The plasma concentrations of probe drugs and their corresponding metabolites were determined by UPLC-MS/MS. The influence of ZGGJP on the activities of seven CYPs were evaluated the metabolic ratios (Cmax and AUC0-t) for metabolites/probe drugs. In addition, the effects of ZGGJP on the mRNA expression of CYPs and their corresponding nuclear receptors in rat liver were evaluated by real-time PCR. Results ZGGJP showed significant inductive effects on CYP1A2 and CYP2B6 of both male and female rats. The influence of ZGGJP on CYP2C9 and CYP3A showed gender difference. ZGGJP could induce the activities of CYP2C9 and CYP3A in female rats, but have no influence on the activities in male rats. ZGGJP had no effects on CYP2D6, CYP2C19 and CYP2E1. The mRNA expression results of CYPs were in accordance with the pharmacokinetic results. The mRNA expression levels of constitutive androstane receptor (CAR) and vitamin D receptor (VDR) were increased significantly in female rats at high dosage, but no significant changes were observed in male rats. Conclusion ZGGJP had inductive effects on CYP1A2 and CYP2B6 in both male and female rats. The results showed that ZGGJP could induce the activities of CYP2C9 and CYP3A in female rats, but had no effect in male rats. This may suggest that the influence of ZGGJP on CYP2C9 and CYP3A exhibit gender difference. The inductive effects of ZGGJP on the activities of CYPs, exhibiting gender difference, may be regulated by CAR and VDR. Therefore, co-administration of ZGGJP with other drugs, especially using CYP2C9 and CYP3A substrates in females, may need dose adjustment to avoid herb-drug interaction.
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- 2021
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20. Drug Repurposing of Itraconazole and Estradiol Benzoate against COVID‐19 by Blocking SARS‐CoV‐2 Spike Protein‐Mediated Membrane Fusion
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Yan Wu, Chan Yang, Xinfeng Xu, Xiaoge Niu, Wei Xu, Yunxia Xu, Weijuan Shang, Yihong Wan, Xiaoyan Pan, Gengfu Xiao, Rong Zhang, Chen Cheng, Zhaofeng Li, Yuan Huang, and Shuwen Liu
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fusion inhibitor ,viruses ,Protein subunit ,Pharmaceutical Science ,Medicine (miscellaneous) ,Pharmacology ,medicine.disease_cause ,SARS‐CoV‐2 ,chemistry.chemical_compound ,estradiol benzoate ,Viral entry ,medicine ,Pharmacology (medical) ,Genetics (clinical) ,Coronavirus ,Full Paper ,Chemistry ,fungi ,Biochemistry (medical) ,virus diseases ,Lipid bilayer fusion ,spike ,Full Papers ,biochemical phenomena, metabolism, and nutrition ,In vitro ,itraconazole ,respiratory tract diseases ,Heptad repeat ,Drug repositioning ,Estradiol benzoate - Abstract
SARS‐CoV‐2 caused the emerging epidemic of coronavirus disease in 2019 (COVID‐19). To date, there are more than 82.9 million confirmed cases worldwide, there is no clinically effective drug against SARS‐CoV‐2 infection. The conserved properties of the membrane fusion domain of the spike (S) protein across SARS‐CoV‐2 make it a promising target to develop pan‐CoV therapeutics. Herein, two clinically approved drugs, Itraconazole (ITZ) and Estradiol benzoate (EB), are found to inhibit viral entry by targeting the six‐helix (6‐HB) fusion core of SARS‐CoV‐2 S protein. Further studies shed light on the mechanism that ITZ and EB can interact with the heptad repeat 1 (HR1) region of the spike protein, to present anti‐SARS‐CoV‐2 infections in vitro, indicating they are novel potential therapeutic remedies for COVID‐19 treatment. Furthermore, ITZ shows broad‐spectrum activity targeting 6‐HB in the S2 subunit of SARS‐CoV and MERS‐CoV S protein, inspiring that ITZ have the potential for development as a pan‐coronavirus fusion inhibitor., An effective drug against COVID‐19 is urgently needed while the current SARS‐CoV‐2 pandemic. Here Itraconazole and Estradiol benzoate are identified to inhibit SARS‐CoV‐2 infection via blocking the spike protein S2 subunit‐mediated membrane fusion and entry into the host cell by targeting the highly conserved six‐helical bundle (6‐HB) fusion core. Furthermore, Itraconazole is confirmed as a potential broad‐spectrum coronavirus fusion inhibitor.
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- 2021
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21. Characterization of Antimicrobial Peptides Isolated from the Processing by-Products of African Catfish Clarias gariepinus
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Xiaomei Wang, Yan Wang, Fan Tianguo, Li Tao, Ze Fan, and Yunxia Xu
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0301 basic medicine ,Clarias gariepinus ,Protease ,030102 biochemistry & molecular biology ,medicine.medical_treatment ,Antimicrobial peptides ,Bioengineering ,Biology ,Antimicrobial ,biology.organism_classification ,Biochemistry ,Clarias ,Analytical Chemistry ,Microbiology ,03 medical and health sciences ,Aeromonas hydrophila ,030104 developmental biology ,Drug Discovery ,medicine ,Molecular Medicine ,Ammonium sulfate precipitation ,Catfish - Abstract
Antimicrobial peptides (AMPs) as components of innate immunity system have been isolated from fish and other species. In this study, the crude proteins extracted with gradient ammonium sulfate precipitation technique from the processing by-products of African catfish Clarias gariepinus (C. gariepinus) were purified by size-exclusion chromatography and all the four obtained fractions, Clarias antimicrobial peptides I(CAP-I), CAP-II, CAP-III and CAP-IV, showed antimicrobial activity. Among of these fractions, CAP-IV showed the highest antimicrobial activity against Staphylococcus aureus, Aeromonas sobria, Aeromonas hydrophila, Escherichia coli by agar diffusion plate test and the diameter of inhibition zone was 8.34, 9.27, 6.76, 6.13 mm, respectively. The molecular weight of main peptides of CAP-IV was around 4.1 KD by SDS-PAGE analysis. CAP-IV showed antimicrobial activity against both gram-negative and gram-positive bacterial pathogens at minimum inhibitory concentrations (MICs) ranging from 105 to 420 μg/mL. The antimicrobial activity of CAP-IV was stable at wide pH range, 3–11 and was also heat-stable when temperature was below 80 °C. Freeze-thawing treatment also only had slight effects on the antimicrobial activity of CAP-IV. Besides, CAP-IV was not sensitive to the hydrolysis by pepsin and trypsin, except for protease K. These results suggest that CAP-IV isolated from C. gariepinus is potential to be developed as a new antimicrobial peptide and may partially explain the high disease resistance of African catfish C. gariepinus.
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- 2016
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22. Enhanced dechlorination of 2,6-dichlorophenol by carbon nanotubes supported Fe/Ni nanoparticles: Characterization, influencing factors, and kinetics
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Jingtao Dai, Zheng-Hao Fei, Xiao-Ju Wen, Yunxia Xu, Pingting Gao, Congcong Ding, Yufeng Sun, and Zongtang Liu
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Hydrogen ,Environmental remediation ,Kinetics ,chemistry.chemical_element ,Nanoparticle ,02 engineering and technology ,Carbon nanotube ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,0104 chemical sciences ,Catalysis ,law.invention ,Colloid and Surface Chemistry ,chemistry ,Chemical engineering ,law ,Mass transfer ,Reactivity (chemistry) ,0210 nano-technology - Abstract
For the first time, the dechlorination of 2,6-dichlorophenol (2,6-DCP) by carbon nanotubes supported Fe/Ni nanoparticles (CNTs-Fe/Ni) was studied to explore the practicability of environmental remediation. Removal capacity of CNTs-Fe/Ni for 2,6-DCP was enhanced obviously compared to Fe/Ni due to reduced aggregation of Fe/Ni nanoparticles.The removal efficiency increased as the increase of CNTs-Fe/Ni dosage and Ni loading, whereas it decreased as the increase of 2,6-DCP concentration. Weak acidic condition was considered to be advantageous to 2,6-DCP dechlorination. The dechlorination kinetics results suggested that the 2,6-DCP removal by CNTs-Fe/Ni accorded with pseudo-first-order equation. Moreover, carbon nanotubes as support accelerated the mass transfer of 2,6-DCP from solution to catalyst surface and promoted the formation of atomic hydrogen, which also led to an enhancement of reactivity of CNTs-Fe/Ni on removing 2,6-DCP.
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- 2020
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23. Molecular dynamics study on loading mechanism of chitosan into boron nitride nanotubes
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Li Zhang, Chen Chen, Xinping Wang, Shen Jia-Wei, Yunxia Xu, Wei Zhang, Jin Zhang, Jiachen Li, Lijun Liang, and Zhe Kong
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Materials science ,02 engineering and technology ,010402 general chemistry ,01 natural sciences ,Chitosan ,chemistry.chemical_compound ,symbols.namesake ,Molecular dynamics ,Materials Chemistry ,Physical and Theoretical Chemistry ,Spectroscopy ,Solvation ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,Atomic and Molecular Physics, and Optics ,0104 chemical sciences ,Electronic, Optical and Magnetic Materials ,Gibbs free energy ,Solvent ,chemistry ,Chemical engineering ,Boron nitride ,Functional group ,Drug delivery ,symbols ,0210 nano-technology - Abstract
Boron nitride nanotubes (BNNTs) have been considered as one of the most promising materials in drug delivery systems. It is important to understand the interaction mechanism between chitosan and BNNTs from atomic level. Herein, molecular dynamics (MD) simulation were employed to investigate the interaction mechanism and loading mechanism of chitosan into/onto BNNTs. The effect of functional group in chitosan and the diameter of BNNTs on the interaction mechanism between BNNTs and chitosan were discussed. It is found that chitosan can only absorb on the outer surface of BNNT (12,12) owing to the size of chitosan and its solvent layer. The loading process of chitosan with –NH2 group (CS_A10) into the BNNT (14,14) is much easier than that for –NH3+ group system (CS_B10). The different loading dynamics for CS_A10/CS_B10 were explained from Gibbs free energy as well as the solvation behavior of chitosan chains.
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- 2020
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24. An Improved Model for Short-Term Traffic Forecasting Considering Weather Impacts
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Yunxia Xu, Xinchao Chen, Si Qin, Xiaoxuan Chen, Jian Zhang, Guanchen Dai, and Huachun Tan
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Econometrics ,Environmental science ,Term (time) - Published
- 2018
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25. How to developed a set of methods for placing a biliary drainage tube through the cystic duct
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Huiqiu Guan and Yunxia Xu
- Subjects
Adult ,Aged, 80 and over ,Male ,Biliary drainage ,medicine.medical_specialty ,business.industry ,Cystic Duct ,Middle Aged ,Surgery ,Young Adult ,medicine.anatomical_structure ,Bile ,Drainage ,Humans ,Medicine ,Cystic duct ,Female ,Tube (fluid conveyance) ,Intubation ,business ,Aged - Published
- 2019
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26. Comparison of Different Protocols of Gradient Ammonium Sulfate Fractionation of Antibacterial Proteins/Peptides from Clarias gariepinus Wastes
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Li Zhuanzhuan, Li Tao, Jinwei Gao, Yunxia Xu, Chengxun Chen, Xiaomei Wang, and Yan Wang
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inorganic chemicals ,Clarias gariepinus ,Ammonium sulfate ,Chromatography ,biology ,Antimicrobial peptides ,food and beverages ,Fractionation ,biology.organism_classification ,Ammonium sulfate fractionation ,chemistry.chemical_compound ,chemistry ,Saturation (chemistry) ,Polyacrylamide gel electrophoresis - Abstract
In this study, gradient ammonium sulfate [(NH4)2SO4] precipitation technique was employed to extract antibacterial proteins/peptides from C. gariepinus wastes. 20, 40 and 60% were respectively used as initial saturation of (NH4)2SO4, then some indexes of crude proteins/peptides obtained at 80 and 100% saturation (NH4)2SO4 were compared. The yield of crude extracts obtained at 80% saturation (NH4)2SO4 was the highest when the material was precipitated initially at 60% saturation (NH4)2SO4. However, the yields of the fractions at 100% saturation (NH4)2SO4, precipitated initially at 20%, 40% and 60% saturation (NH4)2SO4, respectively, didn’t show significant differences. All of crude extracts had inhibitory activity against A. hydrophila, E. coli and S. aureus. The extracts obtained at the same saturation didn’t display obvious different patterns on the SDS-PAGE gel. Based on the results above-mentioned, we proposed that 60% saturation (NH4)2SO4 could be used as initial saturation in gradient (NH4)2SO4 fractionation for obtaining antibacterial proteins/peptides from C. gariepinus wastes.
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- 2017
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27. Adhesion and water lubrication of silastic micro-fiber arrays with monolayer surface modification
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Zhendong Dai, Yunxia Xu, Yan Ding, Dongjie Guo, and Zhan-Shi Jiao
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Materials science ,technology, industry, and agriculture ,macromolecular substances ,02 engineering and technology ,Adhesion ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Porous silicon ,Methacrylate ,01 natural sciences ,Surface energy ,0104 chemical sciences ,Contact angle ,Monolayer ,Surface modification ,Adhesive ,Composite material ,0210 nano-technology - Abstract
This study describes different surface energy monolayer modified Silastic micro-fiber Arrays (PDMS Arrays) to enhance the adhesion and water lubrication performances of PDMS Arrays. A multistep fabrication process consisting of electrochemical etching silicon wafers, cast PDMS Arrays, grafts poly(methylhydrosiloxane) (PMHS) onto PDMS Arrays, and modified the PDMS Arrays surface with Poly(ethylene glycol) methyl ether methacrylate(PEG-MA) and Poly(tetrafluoroethylene acrylate) (PTFE-PA), an intrinsically adhesive synthetic polymer. Attenuated total reflectance-fourier transform infrared (ATR-FTIR) spectroscopy was used to monitor the entire process. Results showed that Si-H peak disappeared and two characteristic peaks appeared means PEG-MA and PTFE-PA successful graft to PDMS Arrays Surface. Results from cohesive tests showed that the adhesion of PEG-MA-g-PDMS Arrays enhance, but the adhesion of PTFE-PA-g-PDMS Arrays decrease. Results from water lubrication tests showed that the hydrophilicity of PEG-MA-g-PDMS Arrays increase, contact angle from 122.5° to 94.2°, but PTFE-PA-g-PDMS Arrays contact angle is increased to 129.1°.
- Published
- 2017
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28. Separation of acetic acid/water mixtures by pervaporation with composite membranes of sodium alginate active layer and microporous polypropylene substrate
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Shui Lu, Zhejun Yu, Wei Zhang, Xinping Wang, and Yunxia Xu
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chemistry.chemical_classification ,Polypropylene ,Materials science ,Substrate (chemistry) ,Filtration and Separation ,Polymer ,Microporous material ,Biochemistry ,Solvent ,chemistry.chemical_compound ,Acetic acid ,Membrane ,chemistry ,Chemical engineering ,Polymer chemistry ,General Materials Science ,Pervaporation ,Physical and Theoretical Chemistry - Abstract
A new kind of composite membrane for the pervaporation dehydration of acetic acid was prepared by casting sodium alginate (NaAlg) solution onto a microporous polypropylene membrane (MPPM) which possessed well-controlled porosity and excellent solvent resistance. The MPPM surface was modified by N2 plasma prior to the fabrication of the corresponding NaAlg-based composite membrane in order to improve its compatibility with the NaAlg active layer. The active layer of the NaAlg/MPPM composite membrane was then cross-linked with multivalent ions. This cross-linking behavior restricted the mobility of the polymer chains in the active layer and accordingly increased their relaxation time. Interestingly, the activation energy of the pervaporation process increased linearly with the relaxation time. Pervaporation results indicated that the prepared composite membranes exhibited desirable separation properties, and a good compromise between flux and separation factor was observed. For the separation of an 80/20 wt% acetic acid/water mixture at 50 °C, the Ca2+ cross-linked composite membrane (Ca-Alg/MPPM) displayed a separation factor of 631 and a flux of 653 g/m2 h, which surpassed most NaAlg-based homogeneous membranes and other composite membranes reported in the literature. These results suggest that the prepared composite membranes have promising potential for acetic acid dehydration.
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- 2014
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29. Electrospun nanofibrous mats as skeletons to produce MOF membranes for the detection of explosives
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Yuquan Wen, Yi-nan Wu, Yunxia Xu, Wei Zhu, Guangtao Li, and Changxu Lin
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Materials science ,Explosive material ,Mechanical Engineering ,Nanotechnology ,Condensed Matter Physics ,Electrospinning ,Membrane ,Nitroaromatic explosives ,Mechanics of Materials ,General Materials Science ,Thin film ,Luminescence ,Porosity ,Seed crystal - Abstract
The report of using electrospun nanofibrous mats as skeletons to produce self-supporting and integrated Zn-MOF membranes was described, which can be used as a new kind of porous supports for the development of MOF membranes. Thin films of Zn-MOF/PST- 1 with a macroporous network structure were prepared by using electrospinning technique. The secondary growth technique was developed to strongly anchor Zn-MOF seed crystals on porous supports Zn-MOF/PST- 1 to form Zn-MOF/PST- 2 thin films. The MOF films of secondary growth have a good fluorescence quenching sensitivity to the nitroaromatic explosives such as dinitrotoluene (DNT), 2,4,6-trinitrotoluene (TNT), and thus can be good candidates for trace nitroaromatic explosives detection.
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- 2012
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30. Preparation of poly(vinyl alcohol)-based membranes with controllable surface composition and bulk structures and their pervaporation performance
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Wei Zhang, Zhennan Zhang, Xinping Wang, Xinzhen Zhao, and Yunxia Xu
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Vinyl alcohol ,Materials science ,Polytetrafluoroethylene ,Substrate (chemistry) ,Filtration and Separation ,Biochemistry ,Casting ,chemistry.chemical_compound ,Crystallinity ,Membrane ,chemistry ,Chemical engineering ,Polymer chemistry ,General Materials Science ,Pervaporation ,Physical and Theoretical Chemistry ,Acrylic acid - Abstract
Poly(vinyl alcohol)-based membranes with controllable surface structures and bulk characteristics were prepared by casting PVA/poly(acrylic acid) (PAA) solutions onto different substrates. Four kinds of surfaces, namely the air-side 1 and glass-side surface (a glass plate used as substrate), the air-side 2 and PTFE-side surface (a polytetrafluoroethylene (PTFE) plate used as substrate), were formed. At any a given content of PAA in PVA casting solution, the air-side 1 and PTFE-side surfaces of the resulting membranes were less hydrophilic than the corresponding glass-side and air-side 2. Interestingly, there was similar surface composition between the air-side 1 and PTFE-side, and between the glass-side and air-side 2. Furthermore, the membranes prepared on a PTFE plate exhibited higher crystallinity than those formed on a glass plate. By an induction of the underlying substrates, the surface composition and bulk characteristics of those PVA-based membranes could be tuned. Pervaporation experiments for separating acetic acid/water mixtures through those membranes were carried out, and the results indicated that the permselectivity was mainly dependent on membrane surface composition, whereas the permeability was more significantly governed by membrane bulk characteristics. This provides a feasible method for the structure optimization of a high-efficient membrane and mechanism exploration in pervaporation separation.
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- 2012
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31. Inhibition of herpes simplex virus infection by oligomeric stilbenoids through ROS generation
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Ren-Xiang Tan, Hui Ming Ge, Yunxia Xu, Xiaoqing Chen, Erguang Li, Taixiang Liu, Ziying Yang, Haishi Qiao, and Lanfang Xu
- Subjects
MAPK/ERK pathway ,Herpesvirus 2, Human ,Herpesvirus 1, Human ,Stilbenoid ,Biology ,Resveratrol ,medicine.disease_cause ,Inhibitory postsynaptic potential ,Antiviral Agents ,Cell Line ,chemistry.chemical_compound ,Virology ,Stilbenes ,medicine ,Animals ,Humans ,Pharmacology ,chemistry.chemical_classification ,Reactive oxygen species ,Innate immune system ,Free Radical Scavengers ,Acetylcysteine ,Herpes simplex virus ,chemistry ,Biochemistry ,Cell culture ,Reactive Oxygen Species - Abstract
Stilbenoids including resveratrol contain the basic structural unit of 1,2-diphenylethylene. Naturally occurring stilbenoids have broad structural features due to oligomerization and modifications and some have demonstrated potent biological activities. In an effort to identify bioactive stilbenoids, we screened a group of dimeric and oligomeric stilbenoids against HSV-1 and HSV-2 infection. Several trimeric and tetrameric derivatives showed anti-herpetic activity at single digit micromolar concentrations. HSV-1 and HSV-2 replication requires for NF-κB and MAPK activation. The compounds showed no inhibitory activity against NF-κB and Erk/MAPK activation, instead those compounds promoted rapid and transient release of reactive oxygen species (ROS). Addition of N-acetylcysteine (NAC), a scavenger of ROS, reversed the inhibitory effect of those compounds against HSV replication. In addition to the identification of resveratrol derivatives with potent anti-HSV activity, our results uncover a mechanism of polyphenol-mediated anti-HSV response, linking anti-herpetic activity of oligomeric stilbenoids to innate immunity.
- Published
- 2012
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32. Identification of OASL d, a splice variant of human OASL, with antiviral activity
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Yunxia Xu, Zhiwei Wu, Xiaoyan Li, Xuancheng Guo, Guang Yang, Erguang Li, and Tian Sun
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Gene isoform ,Sequence analysis ,Biology ,Transfection ,Biochemistry ,Exon ,Downregulation and upregulation ,Cell Line, Tumor ,Chlorocebus aethiops ,2',5'-Oligoadenylate Synthetase ,Animals ,Humans ,Protein Isoforms ,Vero Cells ,Alternative splicing ,RNA ,Exons ,Hep G2 Cells ,Interferon-beta ,Cell Biology ,New variant ,Virology ,Molecular biology ,HEK293 Cells ,Gene Expression Regulation ,Ectopic expression ,Gene Deletion ,HeLa Cells - Abstract
The 2′,5′-oligoadenylate synthetases (OASs) are IFN-induced antiviral proteins and are upregulated by infection of viral and some bacterial pathogens. There are at least 2 transcripts of approximately 1.8 and 2.0 kb in interferon-beta treated samples that are recognized by a probe for human OASL in Northern blot assay. By RT-PCR amplification we have isolated a previously undescribed splice variant of human OASL, named OASL d. The new variant was derived from deletion of exons 4 and 5 and encodes a protein of 384 aa residues that shares the N-terminal 219 aa residues with OASL a. Sequence analysis indicates that OASL d also contains the entire ubiquitin-like domain identified in human OASL a. OASL d was strongly induced by IFNγ in THP-1 monocytic cells and in A549 epithelial cells by interferon-beta as detected by immunoblotting assay. Ectopic expression of OASL a or OASL d, but not OASL b that shares the N-terminus with OASL a and d, partially inhibited EV71 and VSV infection. No effect against HSV-2 infection was observed. Therefore, OASL d is a novel isoform of human OASL that possesses antiviral activity against RNA viruses.
- Published
- 2012
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33. Hybrid nanofibrous mats with remarkable solvent and temperature resistance produced by electrospinning technique
- Author
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Changxu Lin, Yunxia Xu, Yi-nan Wu, Guangtao Li, and Yuquan Wen
- Subjects
Materials science ,Mechanical Engineering ,Composite number ,Condensed Matter Physics ,Electrospinning ,Styrene ,Solvent ,Silanol ,chemistry.chemical_compound ,chemistry ,Chemical engineering ,Polymerization ,Mechanics of Materials ,Polymer chemistry ,Copolymer ,General Materials Science ,Thermal stability - Abstract
A novel organic/inorganic hybrid copolymer poly[styrene- co -3-(trimethoxysilyl)propyl-methacrylate] [P(St- co -TMSPMA)] (denoted as PST) was successfully prepared from styrene and TMSPMA by free-radical polymerization. These composite fiber mats of PST were fabricated via a typical electrospinning process using a single solvent system. As shown in the SEM, the PST composite nanofibers have a smooth and uniform surface and the average diameter is about 0.2 ± 0.04 μm. After the methoxysilyl groups (Si O CH 3 ) were hydrolyzed toward silanol groups (Si OH), the nanofibrous mats exhibited remarkable solvent and temperature resistance. On account of good chemical and thermal stability, this hybrid mats can provide a useful platform for developing functionalized mat systems.
- Published
- 2012
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34. Houttuynia cordata blocks HSV infection through inhibition of NF-κB activation
- Author
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Jingjing Wang, Zhongxia Wang, Ren-Xiang Tan, Ziying Yang, Xiaoqing Chen, Yunxia Xu, and Erguang Li
- Subjects
MAPK/ERK pathway ,Herpesvirus 2, Human ,viruses ,Viral Plaque Assay ,Herpes simplex virus ,Pharmacology ,Virus Replication ,medicine.disease_cause ,Antiviral Agents ,Article ,NF-κB ,Virus ,Inhibitory Concentration 50 ,chemistry.chemical_compound ,Virology ,Chlorocebus aethiops ,medicine ,Animals ,Humans ,heterocyclic compounds ,Houttuynia ,Antiviral ,Vero Cells ,biology ,Plant Extracts ,NF-kappa B ,Viral Load ,biology.organism_classification ,Quercitrin ,Houttuynia cordata ,ACV, acyclovir ,chemistry ,Flavonoid ,Vero cell ,Quercetin ,HeLa Cells ,HCWE, Houttuynia cordata water extract - Abstract
Highlights ►Houttuynia cordata Thunb. exhibits strong activity against herpes simplex virus. ►H. cordata blocks HSV-2 infection through inhibition of NF-κB, not MAPK. ► Flavonoids like quercetin, quercitrin and isoquercitrin as major active components., Houttuynia cordata Thunb. is a medicinal plant widely used in folk medicine in several Asian countries. It has been reported that a water extract of H. cordata exhibits activity against herpes simplex virus (HSV) and the virus of severe acute respiratory syndrome (SARS), although the mechanisms are not fully understood yet. Previous studies have demonstrated absolute requirement of NF-κB activation for efficient replication of HSV-1 and HSV-2 and inhibition of NF-κB activation has been shown to suppress HSV infection. Here we show that a hot water extract of H. cordata (HCWE) inhibits HSV-2 infection through inhibition of NF-κB activation. The IC50 was estimated at 50 μg/ml of lyophilized HCWE powder. At 150 and 450 μg/ml, HCWE blocked infectious HSV-2 production by more than 3 and 4 logs, respectively. The inhibitory activity was concomitant with an inhibition of NF-κB activation by HSV-2 infection. Although activation of NF-κB and Erk MAPK has been implicated for HSV replication and growth, HCWE showed no effect on HSV-2-induced Erk activation. Furthermore, we show that treatment with quercetin, quercitrin or isoquercitrin, major water extractable flavonoids from H. cordata, significantly blocked HSV-2 infection. These results together demonstrated that H. cordata blocks HSV-2 infection through inhibition of NF-κB activation.
- Published
- 2011
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35. Influence of Capping Layers on Magnetic Anisotropy in Fe/MgO/GaAs(100) Ultrathin Films
- Author
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Yu Fu, Yongbing Xu, Hongru Zhai, Wen Zhang, Zhaocong Huang, Ping Kwan Johnny Wong, Ya Zhai, and Yunxia Xu
- Subjects
Materials science ,Spintronics ,Condensed matter physics ,Magnetic structure ,Magnetoresistance ,Crystal structure ,Ferromagnetic resonance ,Electronic, Optical and Magnetic Materials ,Overlayer ,Condensed Matter::Materials Science ,Magnetic anisotropy ,Condensed Matter::Superconductivity ,Electrical and Electronic Engineering ,Anisotropy - Abstract
Magnetic anisotropies of Fe/MgO/GaAs(100) hybrid structure with two different nonmagnetic capping materials, Au and MgO have been studied by ferromagnetic resonance (FMR). A uniaxial anisotropy, unexpected from the crystal structure was observed in the ultrathin films for both capping materials. Its global easy axis is along [0-11] direction while two (010) directions are equally magnetic hard regardless of the overlayer material. The in-plane uniaxial anisotropy (in-plane cubic anisotropy) of the Au capped samples is stronger (weaker) than that of the MgO capped ones within the range of t Fe = 7.1 to 28 ML. This suggests that the MgO overlayer suppresses the uniaxial anisotropy faster than the Au overlayer.
- Published
- 2008
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36. Optimization of Extraction Conditions for Crude Antibacterial Proteins/Peptides from Clarias gariepinus By-products
- Author
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Chengxun Chen, Yunxia Xu, Yan Wang, Xiaomei Wang, and Junyan Mei
- Subjects
Clarias gariepinus ,biology ,Extraction (chemistry) ,Antimicrobial ,biology.organism_classification ,medicine.disease_cause ,Acetic acid ,chemistry.chemical_compound ,Aeromonas hydrophila ,chemistry ,medicine ,Food science ,Antibacterial activity ,Escherichia coli ,Bacteria - Abstract
In this paper, acetic acid was used for extracting crude antimicrobial proteins/peptides from by-products of healthy Clarias gariepinus reared at high stocking density. For the extraction process, three variables, namely the concentration of acetic acid, extraction time, and the ratio of liquid to solid were optimized by using orthogonal design L9(33) with the yield and antibacterial activity of the crude proteins/peptides extracts as test indices. The yields of extracted crude proteins were analyzed by range analysis. The results showed that the yield of crude proteins/peptides was different among nine groups, the highest was group 7, producing 1.5842 g (dialyzed in 1,000 MWCO and lyophilized) per 100 g raw material. All the nine extracted samples had similar inhibitory activity against Aeromonas hydrophila, Escherichia coli, Staphylococcus aureus, Citrobacter sp., and Microbacterium sp. except that groups 7 and 9 exhibited higher inhibitory activity against A. hydrophila and E. coli; moreover, the inhibitory activity of group 7 was higher than group 9 against the two bacteria strains. Nine groups did not display obvious different patterns on the SDS-PAGE gel. Based on these results above, the final conclusion was that group 7, namely 10 % acetic acid, 12 h extraction, and 5:1 liquid to solid ratio was the best combination for isolating the crude antimicrobial proteins/peptides from by-products of C. gariepinus.
- Published
- 2015
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37. Recovery of Pseudomonas aeruginosa from Diseased Grass Carp (Ctenopharyngodon idella) in China
- Author
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Zhang Luo, Yunxia Xu, Zhengguo Zhang, Xiaohui Bai, Shouming Feng, Hao Shuang, and Li Nan
- Subjects
Infectivity ,Pseudomonas aeruginosa ,Aquatic Science ,Biology ,Antimicrobial ,medicine.disease_cause ,Pathogenicity ,biology.organism_classification ,medicine.disease ,16S ribosomal RNA ,Grass carp ,Microbiology ,Ctenopharyngodon idellus ,medicine ,Agronomy and Crop Science ,Epizootic - Abstract
An epizootic was discovered in grass carp (Ctenopharyngodon idellus) in earthen ponds in Ninghe, Tianjin Province, northern China, from May to June 2013. The cumulative mortality was 30% within 25 days, and the diseased fish presented with hemorrhaging in the abdominal wall, ascites in the abdomen and pale liver. Strains named PA131207 and PA131208 were isolated from the moribund fish, and were identified as Pseudomonas aeruginosa according to both biochemical tests and phylogenetic analysis derived from the 16S rRNA gene. The pathogenicity of PA131207 was confirmed by infectivity experiments and histopathological examination. Antimicrobial susceptibility tests showed that PA131207 was resistant to 9 of 15 antimicrobial agents tested.
- Published
- 2015
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38. Evolution of magnetic anisotropy in epitaxial Fe films by ferromagnetic resonance
- Author
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Yongbing Xu, Lin Shi, J. A. C. Bland, Ya Zhai, Wen Zhang, Wen-Xin Tang, Hongru Zhai, Yunxia Xu, X.F Jin, and Ming-Hui Lu
- Subjects
Magnetic anisotropy ,Materials science ,Condensed matter physics ,Ferromagnetism ,Monolayer ,General Physics and Astronomy ,Perpendicular anisotropy ,Anisotropy ,Magnetocrystalline anisotropy ,Epitaxy ,Ferromagnetic resonance - Abstract
Single-crystal Fe films of 4 to 33 monolayers (ML) on GaAs (100) prepared by molecular-beam epitaxy were studied by ferromagnetic resonance (FMR). The evolution of both in-plane and out-of-plane anisotropies was observed. The FMR data show a predominant in-plane uniaxial magnetic anisotropy in the films with the thickness t less than 12.7 ML, with an easy axis along the 〈11_0〉 direction. An in-plane fourfold anisotropy due to cubic magnetocrystalline anisotropy starts to appear and coexists with uniaxial magnetic anisotropy when t=8.4 ML, and increases with increasing film thickness. For t=33 ML, the cubic anisotropy constant K1 reaches 28.2×104 erg/cm3, which is 60% of the value for bulk bcc Fe. A strong perpendicular anisotropy in the ultrathin Fe films was observed. For t=4 ML, the perpendicular anisotropy constant is as high as 14.6×106 erg/cm3. It decreases with increasing the thickness t and reaches about 2.1×106 erg/cm3 for 33 ML, while a small fourth-order perpendicular anisotropy appears and incr...
- Published
- 2003
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39. Effect and mechanism of Saururus chinensis against herpes dimplex virus
- Author
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Erguang Li, Yunxia Xu, Xiaoyan Li, and Lei Tian
- Subjects
Herpesvirus 2, Human ,viruses ,Virus Replication ,medicine.disease_cause ,Antiviral Agents ,Virus ,HeLa ,chemistry.chemical_compound ,Western blot ,Saururaceae ,Chlorocebus aethiops ,medicine ,Animals ,Humans ,Pharmacology (medical) ,General Pharmacology, Toxicology and Pharmaceutics ,Vero Cells ,IC50 ,Cytopathic effect ,biology ,medicine.diagnostic_test ,NF-kappa B ,NF-κB ,biology.organism_classification ,Molecular biology ,Herpes simplex virus ,Complementary and alternative medicine ,chemistry ,Viral replication ,Drugs, Chinese Herbal ,HeLa Cells ,Signal Transduction - Abstract
OBJECTIVE To seek effective drugs inhibiting herpes simplex virus (HSV-2) with the signal pathway required by virus replication as the target spot. METHOD HSV-2-induced Vero cytopathic effect was observed, and MTT method was adopted to detect call activity, in order to assess the antiviral capacity of freeze dried powder of aqueous extracts of Saururus chinensis (AESC). Western blot was used to check the effect of AESC on signal pathway induced by HSV-2 virus in HeLa cells. RESULT AESC obviously inhibits the pathway activation of CPE induced by HSV-2 infection and NF-kappaB required for virus replication. The inhibition ratio of AESC freeze dried powder at 0.10, 0.03, 0.01 and 0.003 g x L(-1) were (70.68 +/- 3.39)%, (61.74 +/- 2.13)%, (39.31 +/- 1.10)% and (18.54 +/- 3.44)%, respectively. The IC50 was determined at (0.023 +/- 0.004) g x L(-1). The inhibition concentration of the positive control acyclovir was 0.001 g x L(-1) (5.0 x 10(-6) mol x L(-1)). The best administration time was from 2 h before infection to 6 h after infection. Western blot also showed that AESC can notably inhibit HSV-2-induced NF-kappaB nuclear transfer. CONCLUSION AESC can inhibit HSV-2 virus replication, which is related to the pathway activation of NF-kappaB required for virus replication.
- Published
- 2012
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40. Syndecan-4 over-expression preserves cardiac function in a rat model of myocardial infarction
- Author
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Jun Xie, Yunxia Xu, Albert Ferro, Biao Xu, Erguang Li, Yonghong Yong, Ruotian Li, Jingjing Wang, Qin Dai, and Bing Zong
- Subjects
Cardiac function curve ,Male ,medicine.medical_specialty ,Myocardial Infarction ,Infarction ,Coxsackie virus and adenovirus receptor ,Neovascularization ,Rats, Sprague-Dawley ,Fibrosis ,Internal medicine ,medicine ,Animals ,Humans ,Myocytes, Cardiac ,Myocardial infarction ,Molecular Biology ,Cells, Cultured ,business.industry ,medicine.disease ,Rats ,Disease Models, Animal ,cardiovascular system ,Cardiology ,Syndecan-4 ,Arteriogenesis ,medicine.symptom ,Cardiology and Cardiovascular Medicine ,business ,Myofibroblast - Abstract
Syndecan-4 (synd4) is a heparan sulfate proteoglycan, involved in repair following tissue damage, through modulating neovascularization and inflammation. In acute myocardial infarction its myocardial expression is up-regulated in a time-dependent manner, and in synd4-deficient mice severe cardiac dysfunction and abnormal remodeling are observed following induction of myocardial infarction. Here we explored the therapeutic potential of sustained synd4 over-expression in the context of myocardial infarction. Adenovirus containing the synd4 gene (Ad-synd4), or corresponding control adenovirus (Ad-null), was administered intramyocardially in rats immediately after induction of myocardial infarction. Cardiac function was ascertained by echocardiography, hemodynamic assessment and brain natriuretic peptide level 28 days post-intervention. Hearts were excised for molecular and histological analyses at predetermined time points. We observed reduced mortality and improved cardiac function post-myocardial infarction in the Ad-synd4 as compared to the Ad-null group, with associated attenuation of cardiac remodeling, less myocyte loss and reduced fibrosis. Additionally, the Ad-synd4 group exhibited endothelial cell activation and increased angiogenesis and arteriogenesis in the myocardium. The Ad-synd4 group also showed evidence of reduced myocardial inflammation as compared with the Ad-null group, with reduced inflammatory cell (CD45+) and myofibroblast (α-SMA+) infiltration as well as suppressed collagen III deposition and iNOS expression. Our results suggest that sustained synd4 over-expression in the myocardium is of therapeutic benefit following experimental myocardial infarction, through inducing neovascularization, suppressing tissue inflammation and fibrosis, with resultant improvements in cardiac function and remodeling.
- Published
- 2012
41. Facile fabrication of photonic MOF films through stepwise deposition on a colloid crystal substrate
- Author
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Yi-nan Wu, Cheng-an Tao, Guangtao Li, Fengting Li, Jiecheng Cui, Wei Zhu, and Yunxia Xu
- Subjects
Fabrication ,Materials science ,business.industry ,Metals and Alloys ,Nanotechnology ,General Chemistry ,Substrate (electronics) ,Catalysis ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials ,Crystal ,Colloid ,Materials Chemistry ,Ceramics and Composites ,Deposition (phase transition) ,Photonics ,business - Abstract
Based on stepwise deposition of MOF films on a colloid crystal substrate, a strategy for fabricating photonic MOF films was developed. We found that the integration of a photonic structure endows MOF materials with unique optical properties, which can be used as a general and effective transduction scheme for a convenient study of the host–guest chemistry of MOFs.
- Published
- 2011
42. EPR of a V4+-doped KTiOPO4single crystal
- Author
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Yaogang Liu, Shiying Han, Jinqian Wei, Jiyang Wang, and Yunxia Xu
- Subjects
chemistry.chemical_classification ,Chemistry ,Doping ,Inorganic chemistry ,Condensed Matter Physics ,Direction cosine ,Ion ,law.invention ,Crystallography ,law ,General Materials Science ,Electron paramagnetic resonance ,Single crystal ,Inorganic compound ,Hyperfine structure ,Principal axis theorem - Abstract
Two groups of EPR hyperfine lines of a V4+ ion substituting for a Ti4+ ion corresponding to two kinds of sites which are Ti(1) and Ti(2) sites in the KTiOPO4 single crystal, are observed at room temperature in the X band. The principal values and direction cosines of the principal axes of the g and A tensors are computed using a least-square fitting procedure for two kinds of sites, and the principal axis of the g tensor of all eight Ti ion sites substituted in a unit cell of KTiOPO4, of which orientations are physically distinct, are revealed.
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- 1992
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43. Interface effects of the magnetic properties in Nd/Ni80Fe20 bilayer films
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Hongru Zhai, Hartmut Zabel, Sheng Jiang, Ya Zhai, Chen Luo, Haibo Huang, Biao You, Yunxia Xu, and Jun Du
- Subjects
Spin pumping ,Materials science ,Condensed matter physics ,Bilayer ,General Physics and Astronomy ,chemistry.chemical_element ,Magnetic hysteresis ,Neodymium ,Ferromagnetic resonance ,Condensed Matter::Materials Science ,Hysteresis ,Exchange bias ,chemistry ,Néel temperature - Abstract
The magnetic properties of Nd/Ni80Fe20 (Py) bilayer films with different layer thicknesses were investigated. Hysteresis loops were measured at different temperatures, an exchange bias effect is found at low temperature due to the Nd/Py interface. By fitting the temperature dependence of the saturation magnetization, the Neel point of Nd layer is obtained. Ferromagnetic resonance (FMR) experiments were carried out at room temperature as a function of Nd layer thickness. The damping parameter obtained by theoretical fitting of the FMR linewidth shows an increasing trend with increasing Nd layer thickness, which is taken as an indication of the spin pumping effect.
- Published
- 2015
- Full Text
- View/download PDF
44. The manipulation of magnetization damping in FeNi1–xNdx/Cu/FeCo1–yGdy sandwich structured multilayers
- Author
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Jun Du, Haibo Huang, Hongru Zhai, Sheng Jiang, Ya Zhai, Chen Luo, Dong Zhang, Wen Zhang, Yunxia Xu, Yukun Wang, and P. K. Johnny Wong
- Subjects
Materials science ,Condensed matter physics ,Magnetic circular dichroism ,Magnetometer ,Magnon ,General Physics and Astronomy ,Magnetic hysteresis ,Ferromagnetic resonance ,law.invention ,Condensed Matter::Materials Science ,Magnetization ,Hysteresis ,Ferromagnetism ,law - Abstract
The magnetic properties and magnetization damping in a series of Ta(5 nm)/Fe20Ni80Nd0.075(3 nm)/Cu(tCunm)/Fe50Co50Gd0.07(3 nm)/Cu(2 nm) multilayers with varying nonmagnetic Cu layer thickness are investigated by vibrating sample magnetometer and ferromagnetic resonance (FMR). Two-step hysteresis loops are observed, indicative of individual switching of the two magnetic layers. The saturation magnetization of the multilayers possesses a very close magnitude to the sum of those for the Fe20Ni80Nd0.075 and Fe50Co50Gd0.07 single layer films, and the difference between each other is within 3% only. Element-specific hysteresis loops of each magnetic elements involved the multilayers are further probed by x-ray magnetic circular dichroism, which reveals that Fe, Ni, and Co are ferromagnetically coupled with Nd and anti-ferromagnetically with Gd. The FMR spectra for the multilayers exhibit two-resonance peaks originated from the two magnetic layers. Compared with the NiFe-Nd and FeCo-Gd single magnetic films, the...
- Published
- 2015
- Full Text
- View/download PDF
45. EPR Study of Manganese-Doped PLZT-8/65/35 Ceramics
- Author
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Maya D. Glinchuk, Shi-Ying Han, V. V. Skorokhod, Yunxia Xu, I. P. Bykov, V. Dimza, and Tong-Zheng Jing
- Subjects
Oxide ceramics ,Chemistry ,Inorganic chemistry ,Doping ,chemistry.chemical_element ,Manganese ,Condensed Matter Physics ,Electronic, Optical and Magnetic Materials ,law.invention ,law ,visual_art ,visual_art.visual_art_medium ,Ceramic ,Electron paramagnetic resonance ,Nuclear chemistry - Published
- 1992
- Full Text
- View/download PDF
46. Magnetic properties of ultrathin single crystal Fe3O4 film on InAs(100) by ferromagnetic resonance
- Author
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Zhaocong Huang, Yunxia Xu, Ya Zhai, X. F. Hu, Hongru Zhai, Jing Wu, and Yongbing Xu
- Subjects
Condensed Matter::Materials Science ,Magnetic anisotropy ,Materials science ,Spintronics ,Magnetic domain ,Magnetic shape-memory alloy ,Condensed matter physics ,General Physics and Astronomy ,Magnetocrystalline anisotropy ,Anisotropy ,Magnetic susceptibility ,Ferromagnetic resonance - Abstract
The evolution of both in-plane and out-of-plane magnetic anisotropies has been studied on different thicknesses of Fe3O4/InAs(100) hybrid spintronic structures by ferromagnetic resonance. The uniaxial magnetic anisotropy with easy axis along InAs [011] direction and hard axis along [0-11] direction and the cubic magnetic anisotropy are determined by fitting the resonance field. The cubic magnetic anisotropy constant K1 is negative, as that of bulk magnetite, and its absolute value increases rapidly from 0.2 × 104 erg/cm3 to 10.8 × 104 erg/cm3 with increasing thickness of Fe3O4 film. When the thickness of Fe3O4 film is only several monolayers (tFe = 6 nm), a bulk-like cubic magneto-crystalline anisotropy is built up. The uniaxial anisotropy constant is much smaller than that in Fe3O4/GaAs film with the same thickness of Fe3O4 film, as expected from the less lattice mismatch at the interface.
- Published
- 2012
- Full Text
- View/download PDF
47. Ferromagnetic resonance studies of Fe thin films with dilute heavy rare-earth impurities
- Author
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Li Sun, Mao Yang, Hongru Zhai, Zhaocong Huang, Yukun Wang, Yunxia Xu, Ya Zhai, and Jun Du
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Materials science ,Dopant ,Condensed matter physics ,Magnetometer ,Doping ,General Physics and Astronomy ,Sputter deposition ,Ferromagnetic resonance ,law.invention ,Condensed Matter::Materials Science ,Magnetization ,law ,Thin film ,Anisotropy - Abstract
The structure and magnetic properties of Fe1−xGd(Tb)x films prepared by sputtering have been investigated using x-ray diffraction, vibrating sample magnetometer, and ferromagnetic resonance. Magnetic measurements show that the saturation magnetization decreases as the increase of Gd(Tb) content, which agrees with that Gd(Tb) atomic moments align antiparallel with Fe moments. Theoretical fittings of the angular dependence of ferromagnetic resonance field yield the second- and forth-order perpendicular anisotropy constants K⊥1 and K⊥2, which show a spin reorientation with increasing Gd(Tb) doping. The intrinsic contribution of ferromagnetic resonance linewidth as a result of Gilbert damping is separated from the extrinsic contribution because of the inhomogeneity of the films. It is found that the additions of Gd additives do not significantly improve the damping constant, whereas the Tb dopants increase the damping constant from 0.04 without Tb to 0.11 with 19% Tb, thus a remarkable enhancement of 175%.
- Published
- 2012
- Full Text
- View/download PDF
48. A study on ferromagnetic resonance linewidth of single crystalline ultrathin Fe film grown on GaAs substrate
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Hongru Zhai, C. Ni, Yongbing Xu, Jing Wu, Yunxia Xu, Ya Zhai, and H. X. Lu
- Subjects
Materials science ,Condensed matter physics ,Film plane ,Physics::Optics ,General Physics and Astronomy ,Ferromagnetic resonance ,Condensed Matter::Materials Science ,Magnetic anisotropy ,Laser linewidth ,Ferromagnetism ,Condensed Matter::Superconductivity ,Monolayer ,Physics::Atomic Physics ,Anisotropy ,Single crystal ,Astrophysics::Galaxy Astrophysics - Abstract
We report ferromagnetic resonance studies on linewidth of single crystal ultrathin Fe films on GaAs(100). For different orientations of the magnetic field in the film plane, anisotropic linewidth has been observed. An expression for anisotropy of linewidth with isotropic damping was derived and also an expression for anisotropic damping constant was proposed. With these two expressions the data of the angular dependence of linewidth of a 5.2 ML (monolayer) film were fitted well. For the thicker film of 25 ML, the fitting of experimental angular dependence of linewidth could be improved if an inhomogeneous broadening is further considered.
- Published
- 2007
- Full Text
- View/download PDF
49. The magnetocrystalline anisotropy of W- type hexagonal ferrites
- Author
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Hongru Zhai, H. Cai, Yunxia Xu, and G. Yang
- Subjects
Magnetic anisotropy ,Materials science ,Condensed matter physics ,Hexagonal crystal system ,Crystal field theory ,Point particle ,Ferrite (magnet) ,Electrical and Electronic Engineering ,Magnetocrystalline anisotropy ,Anisotropy ,Electronic, Optical and Magnetic Materials ,Ion - Abstract
Single ion anisotropy of Fe3+ions at each site of the 7 sublattices 2d, 4e, 4f IV , 4f VI , 6g, 12k, and 4f in the ferrite Zn 2 W has been calculated by crystal field theory using point charge approximation. As expected, the results show that the contributions of different sites are different which may be positive or negative. This model can explain the experimental results of substituted W-type ferrites.
- Published
- 1984
- Full Text
- View/download PDF
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