247 results on '"Jian-Feng Gao"'
Search Results
202. Investigation on surface morphology of sputtered YBa2Cu3Ox thin and ultrathin films
- Author
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W.H. Wong and Jian-Feng Gao
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Materials science ,Morphology (linguistics) ,Scanning electron microscope ,Nucleation ,Energy Engineering and Power Technology ,Substrate (electronics) ,Condensed Matter Physics ,Electronic, Optical and Magnetic Materials ,Crystallinity ,Sputtering ,Electrical and Electronic Engineering ,Thin film ,Composite material ,Layer (electronics) - Abstract
Ultrathin films of YBa 2 Cu 3 O x with good crystallinity and high transition temperatures were prepared by modified off-axis sputtering. The surface morphology of films with thickness down to 2 nm has been studied by scanning electron microscopy and atomic force microscopy. The outgrowths were found to nucleate at the initial growing stage of films. Thus the surface quality of the initially grown layer turned out to be of practical importance in controlling and improving the film-surface morphology. The possible origins of the outgrowths have also been discussed. By employing a substrate with a very good surface and using a suitable deposition temperature, the nucleation of the outgrowths can be greatly suppressed and extremely smooth films up to hundreds nm thickness can be obtained.
- Published
- 1995
203. Biosensing: A Hydrogen-Bonded-Supramolecular-Polymer-Based Nanoprobe for Ratiometric Oxygen Sensing in Living Cells (Adv. Funct. Mater. 30/2016)
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Rui-Fang Wang, Jian-Feng Gao, Hui-Qing Peng, Li-Zhu Wu, Qing-Zheng Yang, Li-Ya Niu, Chen-Ho Tung, Yu-Zhe Chen, and Peng-Zhong Chen
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chemistry.chemical_classification ,Materials science ,Hydrogen ,chemistry.chemical_element ,Nanoprobe ,Nanotechnology ,Condensed Matter Physics ,Electronic, Optical and Magnetic Materials ,Biomaterials ,Supramolecular polymers ,chemistry ,Electrochemistry ,Biosensor ,Oxygen sensing - Published
- 2016
204. Substrate-related structural, electrical, magnetic and optical properties of La0.7Sr0.3MnO3films
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J L Yao, Run Zhao, Jie Qiu, Yucheng Jiang, M Zhao, Guozhen Liu, Jian-Feng Gao, X X Chen, and Y Y Yang
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010302 applied physics ,Materials science ,Acoustics and Ultrasonics ,business.industry ,Nanotechnology ,Heterojunction ,02 engineering and technology ,Substrate (electronics) ,Coercivity ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,Manganite ,Epitaxy ,01 natural sciences ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials ,Magnetization ,0103 physical sciences ,Optoelectronics ,Thin film ,0210 nano-technology ,business ,Perovskite (structure) - Abstract
La0.7Sr0.3MnO3 (LSMO) film exhibits certain unique properties which make it an ideal material for heterostructure-based multifunctional devices. In this paper, La0.7Sr0.3MnO3 thin films were grown epitaxially on SrTiO3, LaAlO3(LAO) and (LaAlO3)0.3-(SrAl0.5Ta0.5O3)0.7(LSAT) substrates, and their structural, electrical, magnetic and optical properties were examined and compared, aiming at revealing and explaining the effects of substrate on fundamental physical properties of LSMO films. Results show that (i) the effects of substrate materials on the electrical conductivity and paramagnetic–ferromagnetic transition temperature of the LSMO films could be ignored, and (ii) the LSMO film on LAO substrate has much higher coercive field and slower photoinduced relaxation process than other samples. This unusual behavior observed in the LSMO film on the LAO substrate could be related to the nature of the LAO substrate itself, on which the LSMO film showed different easy magnetization direction, and the film also exhibited relatively poor crystalline quality due to the twin domain structure of LAO crystal. Our results may help to understand the substrate-related electrical, magnetic and optical properties for perovskite manganite films.
- Published
- 2016
205. Improved Epitaxy and Surface Morphology in <font>YBa</font>2<font>Cu</font>3<font>O</font>y Thin Films Grown on Double Buffered <font>Si</font> Wafers
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Jian-Feng Gao, H. Y. Wong, L. Kang, Y. L. Cheung, and Jinlong Yang
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Superconductivity ,Materials science ,business.industry ,Statistical and Nonlinear Physics ,Nanotechnology ,engineering.material ,Condensed Matter Physics ,Epitaxy ,Buffer (optical fiber) ,Coating ,engineering ,Surface roughness ,Optoelectronics ,Wafer ,Thin film ,business ,Yttria-stabilized zirconia - Abstract
Highly epitaxial thin films of YBCO have been obtained on silicon wafers using a Eu 2 CuO 4/ YSZ (yttrium-stabilized ZrO 2) double buffer. Our results showed that application of such a double buffer can significantly enhance the epitaxy of grown YBCO. It also leads to an excellent surface morphology. The average surface roughness was found less than 5 nm in a large range. The results of X-ray small angle reflection and positron spectroscpy demonstrate a very clear and flat interface between YBCO and buffer layers. The Eu 2 CuO 4/ YSZ double buffer could be promising for coating high-TC superconducting films on various reactive substrates.
- Published
- 2003
206. A comparative theoretical investigation into the strength of the trigger-bond in the Na⁺, Mg²⁺ and HF complexes involving the nitro group of R-NO₂ (R = -CH₃, -NH₂ and -OCH₃) or the C = C bond of (E)-O₂N-CH = CH-NO₂
- Author
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Lin, Zhang, Fu-de, Ren, Duan-lin, Cao, Jian-long, Wang, and Jian-feng, Gao
- Abstract
A comparative theoretical investigation into the change in strength of the trigger-bond upon formation of the Na(+), Mg(2+) and HF complexes involving the nitro group of RNO₂ (R = -CH₃, -NH₂, -OCH₃) or the C = C bond of (E)-O₂N-CH = CH-NO₂ was carried out using the B3LYP and MP2(full) methods with the 6-311++G**, 6-311++G(2df,2p) and aug-cc-pVTZ basis sets. Except for the Mg(2+)⋯π system with (E)-O2N-CH = CH-NO₂ (i.e., C₂H₂N₂O₄⋯Mg(2+)), the strength of the trigger-bond X-NO₂ (X = C, N or O) was enhanced upon complex formation. Furthermore, the increment of bond dissociation energy of the X-NO₂ bond in the Na(+) complex was far greater than that in the corresponding HF system. Thus, the explosive sensitivity in the former might be lower than that in the latter. For C₂H₂N₂O₄⋯Mg(2+), the explosive sensitivity might also be reduced. Therefore, it is possible that introducing cations into the structure of explosives might be more efficacious at reducing explosive sensitivity than the formation of an intermolecular hydrogen-bonded complex. AIM, NBO and electron density shifts analyses showed that the electron density shifted toward the X-NO₂ bond upon complex formation, leading to a strengthened X-NO₂ bond and possibly reduced explosive sensitivity.
- Published
- 2012
207. [Screening of tissues pooled cDNA library using probes by restricted fragments of BAC positive clones of ovine MHC]
- Author
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Xiao-Liang, Yang, Da-Zhang, Bai, Wei, Qiu, Hui-Qin, Dong, Da-Quan, Li, Fang, Chen, Run-Lin, Ma, T Blair, Hugh, and Jian-Feng, Gao
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Major Histocompatibility Complex ,Chromosomes, Artificial, Bacterial ,DNA, Complementary ,Sheep ,Animals ,Nucleic Acid Hybridization ,Sequence Analysis, DNA ,Gene Library - Abstract
Under the premise what we have known bacterial artificial chromosome(BAC)clone sequence information and gene annotation predicted in the Chinese Merino sheep major histocompatibility complex (MHC) region, the digested fragments from 6 BAC clones that were located in the MHC region of the Chinese Merino sheep genome BAC library, which were used to screen the cDNA library using plaque in situ hybridization as probes. The full length of positive cDNA clones (sequences) isolated were completely sequenced, and the sequences obtained were aligned with the corresponding known sequence information and the BAC clones with gene annotation. Meanwhile, the sequence similarity was searched in NCBI Blastn database. This work aimed at verification of accuracy of the gene annotation results and initial analysis of gene (sequence) function. At last, 27 positive cDNA clones (sequences) in total were screened through two runs of hybridization. It was also found that these sequences could be positioned in the corresponding BAC clones, and 25 sequences were located in exon area of the annotated gene. It was verified that 23 sequences had the highest sequence similarity with those in the Bos taurus by searching against the NCBI Blastn database; moreover, the function of these sequences were closely relate to immunology.
- Published
- 2012
208. [Angiogenesis of brain after ischemia/reperfusion injury of brain in aged rats and changes in expressions of basic fibroblast growth factor and transformation growth factor-β1]
- Author
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Jian-Sheng, Li, You-Long, Zhou, Ke, Liu, Jian-Feng, Gao, Xin-Ke, Yang, Yue-Wu, Zhao, Zheng-Guo, Liu, and Jing-Xia, Liu
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Male ,Rats, Sprague-Dawley ,Transforming Growth Factor beta1 ,Aging ,Neovascularization, Pathologic ,Reperfusion Injury ,Animals ,Brain ,Fibroblast Growth Factor 2 ,Brain Ischemia ,Rats - Abstract
To elucidate the mechanism of angiogenesis after cerebral ischemia/reperfusion (I/R) in the aged rats by observing the changes in expressions of basic fibroblast growth factor (bFGF) and transformation growth factor-β1 (TGF-β1).Young Sprague-Dawley (SD) rats were classified into groups by random digits table, and aged SD rats were stratified by different body weight. Rats were randomly divided into groups of sham operation, ischemia (I) 3 hours, I/R 1, 3, 6, 12 days, with 6 rats in each group. Focal cerebral I/R model was reproduced by intraluminal filament technique. Microvessel density (MVD) of brain tissue, sum area of lumens were observed, and the expressions of bFGF protein, TGF-β1 protein and TGF-β1 mRNA were assessed with immunohistochemistry and hybridization in situ.MVD in young model group began to increase at I 3 hours, peaking at I/R 6 days, maintained up to I/R 12 days. MVD in aged model group began to descend at I 3 hours and continued to I/R 12 days. Sum area of lumens in young model group increased markedly at I/R 1 day, gradually lowered at I/R 1-6 days, and increased obviously again at I/R 12 days. Sum area of lumens in aged model group reached peak at I/R 1 day, gradually decreased subsequently. MVD in aged sham operation group were higher than that in young sham operation group (6.88±1.60 vs. 5.50±1.53, P0.01). MVD and sum area of lumens in aged model group at I/R 1, 3, 6, 12 days were lower than young model group. Expressions of bFGF protein, TGF-β1 protein in young and aged model group were both gradually up-regulated, all of them reaching peak at I/R 3 days, and lowered gradually at I/R 3-12 days subsequently. Expressions of bFGF protein (grey level) in both aged sham operation group and those of model group at I 3 hours, I/R 1, 3, 12 days were lower than those of young sham operation and those of the model group at the same time points (176.80±5.10 vs. 172.82±1.53, 171.81±2.43 vs. 167.85±2.41, 167.99±5.51 vs. 164.90±2.15, 152.98±4.11 vs. 150.75±1.11, 165.67±3.55 vs. 161.73±1.29, P0.05 or P0.01). Expressions of TGF-β1 protein (grey level) in both aged sham operation and those of model group at I 3 hours, I/R 1, 3, 6, 12 days were all lower than those of young sham operation and those of model group at the same time points (182.69±3.12 vs. 176.13±4.08, 176.89±2.30 vs. 170.56±7.47, 171.74±2.70 vs. 165.43±2.91, 157.17±5.20 vs. 150.43±4.28, 161.72±4.81 vs. 155.37±2.92, 167.69±2.18 vs. 160.28±3.59, all P0.01). TGF-β1 mRNA expressions in both young model group and aged model group reached peak at I/R 1 day, gradually lowered subsequently. Expressions of TGF-β1 mRNA (gray level) in both aged sham operation and those of model group at I 3 hours, I/R 3, 6, 12 days were lower than those of young sham operation and also model group at the same time points (176.51±9.52 vs. 169.09±5.08, 176.75±5.74 vs. 165.36±4.78, 177.33±5.68 vs. 165.25±8.14, 178.46±4.91 vs. 170.51±4.29, 203.95±4.51 vs. 181.98±5.59, all P0.01).Angiogenesis is obviously weak after cerebral I/R in the aged, and the mechanism of which might be related to the down-regulation of expressions of bFGF protein, TGF-β1 protein and TGF-β1 mRNA. Aging factor may be one of the main reasons which induce the down regulation of expressions mentioned above.
- Published
- 2010
209. Phase Inversion Tape Casting and Electrochemical Performance of Solid Oxide Fuel Cell Anode
- Author
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Yu-Yue, ZHANG, primary, Jie, LIN, primary, Guo-Shuan, MIAO, primary, Jian-Feng, GAO, primary, Chu-Sheng, CHEN, primary, Chang-Rong, XIA, primary, Zhong-Liang, ZHAN, primary, and Shao-Rong, WANG, primary
- Published
- 2015
- Full Text
- View/download PDF
210. Synthesis of an activated carbon based urea formaldehyde resin and its adsorption and recognition performance towards Fe(iii)
- Author
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Guo-Li, Ou, primary, Jian-Feng, Gao, additional, Tuo-Ping, Hu, additional, Fu-Qiang, An, additional, Yu, Wang, additional, Yan-Jun, Wang, additional, and Dong, Zhang, additional
- Published
- 2015
- Full Text
- View/download PDF
211. THE TRANSPORT BEHAVIOR NEAR THE JUNCTION INTERFACE IN RAMP JOSEPHSON JUNCTIONS WITH A GRADED BARRIER
- Author
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Jian-Feng Gao and J. L. Sun
- Subjects
Josephson effect ,Pi Josephson junction ,Materials science ,Condensed matter physics ,Theoretical models ,Statistical and Nonlinear Physics ,Josephson energy ,Critical current ,Condensed Matter Physics - Abstract
The stationary properties of high- T c ramp type Josephson junctions with a graded Y 1-x Pr x Ba 2 Cu 3 O y barrier have been studied. In such a structure the composition of the Y 1-x Pr x Ba 2 Cu 3 O y barrier is continuely changed as x increasing from 0 to 1 at one side of the PrBCO barrier and vice verse at the other side. The critical current of these junctions showed a nearly linear dependence on the temperature. The experimental results were discussed in comparing with theoretical models.
- Published
- 1999
212. TEM Study of Coherently Tilted <font>YBa2Cu3O</font>7-δ Thin Films on (305) <font>SrTiO3</font> Substrates
- Author
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Jian-Feng Gao and Yi Yang
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Optics ,Materials science ,Condensed matter physics ,business.industry ,Substrate surface ,Statistical and Nonlinear Physics ,Yba2cu3o7 δ ,Single domain ,Thin film ,Orientation (graph theory) ,Condensed Matter Physics ,business - Abstract
Microstructural study has been carried out on the YBa2Cu3O 7-δ (YBCO) thin films grown on (305) SrTiO3 (STO) substrates. The results show that the YBCO films are coherently tilted with the c-axis parallel to the [001] direction of STO. Small antidomains are nucleated at the initial growth stage. When the film thickness increases, antidomains disappear leading to the formation of single domain thin films. Some particles are observed above the defective substrate surface, but the film with the favorable orientation suppresses their further growth.
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- 1998
213. Preparation of SDC Interlayer and Influence on Performances of Anode Supported Solid Oxide Fuel Cells
- Author
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Wei Tao Bao, Jian Feng Gao, and Guang Yao Meng
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- 2007
214. YSZ Thin Films Prepared by a Novel Powder Coating Process on Porous NiO-YSZ Cermet
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Wei Tao Bao, Yin Zhu Jiang, Guang Yan Zhu, Jian Feng Gao, and Guang Yao Meng
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- 2007
215. [Neuro-protective effect of Naomaitong to inflammatory cascade response after focal cerebral ischemia reperfusion in aged rats]
- Author
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Jian-Sheng, Li, Jian-Feng, Gao, You-Long, Zhou, and Ke, Liu
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Male ,Plants, Medicinal ,Tumor Necrosis Factor-alpha ,Brain ,Vascular Cell Adhesion Molecule-1 ,Infarction, Middle Cerebral Artery ,Intercellular Adhesion Molecule-1 ,Brain Ischemia ,Rats ,Rats, Sprague-Dawley ,Neuroprotective Agents ,Reperfusion Injury ,Animals ,RNA, Messenger ,Drugs, Chinese Herbal - Abstract
To study the protective effect of Naomaitong on inflammatory cascade response after focal cerebral ischemia reperfusion in aged rats.We duplicated focal cerebral ischemia model with MCAO, with ischemia 3 h and I/R 1, 3, 6, 12 d points. The effect of Naomaitong on the nervous dysfunction score, the water content of cerebral constitution and the expression of TNF-alpha, VCAM-1, ICAM-1 and its mRNA were observed, and the group with nimodipine was as control.The nervous dysfunction score (I/R1, 3, 6 d), the water content of cerebral constitution (all the time points), the expression of TNF-alpha, VCAM-1 (I 3 h, I/R 1, 3, 6 d), ICAM-1 (I 3 h,I/R 1, 3, 6 d) and its Mrna (all the time points) in model group were higher than those of the sham-operated group; The nervous dysfunction score, the water content of cerebral constitution (I/R 3, 6, 12 d), the expression of TNF-alpha, VCAM-1 (I 3 h, I/R 1, 3 d), ICAM-1 and its mRNA (I 3 h, I/R 1, 3 d) in model group were decreased compared with that of model group. The nervous dysfunction score (I/R 6, 12 d), the expression of TNF-alpha, ICAM-1 (I/R 1d) and its mRNA (I/R 1, 3 d) in Naomaitong group were higher than that of Nimodipine group.Naomaitong could protect brain cell from damage after focal cerebral ischemia reperfusion injury by inhibiting the expression of TNF-alpha, adhesion molecule.
- Published
- 2007
216. Tuning competition between metallic and insulating phases with strain, light and electric field in thin films of La0.39Pr0.24Ca0.37MnO3
- Author
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Dan Cao, Zhi-Wei Jiao, Jian-Feng Gao, Sen-Jiang Yu, Jianfeng Wang, and Yun Zhou
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Diffraction ,Materials science ,Acoustics and Ultrasonics ,business.industry ,Photoconductivity ,Relaxation (NMR) ,Biasing ,Condensed Matter Physics ,Manganite ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials ,Electric field ,Optoelectronics ,Thin film ,business ,Voltage - Abstract
The electric field and photo illumination effects in thin films of La0.39Pr0.24Ca0.37MnO3(LPCMO)/SrTiO3 with different thicknesses (15, 40 and 120 nm) have been systematically investigated. X-ray diffraction measurements demonstrate that these grown films are epitaxial and c axis oriented. Due to strain relaxation, these films are in different strain states. It is found that the strain state can greatly change not only the electrical properties but also the responses to external perturbations. The thinner film experiences a larger tensile in-plane strain and has a more robust insulating state. The low-temperature insulating state in the 120 nm sample is readily destroyed by a small electric field or light illumination without a bias voltage. Both the critical light density and the critical electric field used to collapse the insulating state in the 40 nm LPCMO film are much larger than those in the 120 nm sample. It is revealed that the bias electric field and light illumination play complementary roles. Light illumination can reduce the critical bias electric field. The 15 nm sample exhibits a robust insulating state, which cannot be destroyed by a combination of a bias voltage of 200 V (E = 4 × 105 V m−1) and light illumination (λ = 532 nm, P = 2 mW cm−2). Large transient photoconductivity has been observed in the 40 nm sample under low bias voltages and in the 15 nm sample under all bias voltages. The observed transient photoconductivity and persistent photoconductivity are believed to have different origins.
- Published
- 2015
217. Characterization of barrier heights in Nd0.7Sr0.3MnO3/Nb : SrTiO3junctions with current–voltage characteristics
- Author
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Jianfeng Wang, D. Cao, Xinyou Wang, Zhi-Wei Jiao, Jian-Feng Gao, and Sen-Jiang Yu
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Materials science ,Nb doped ,Acoustics and Ultrasonics ,Current voltage ,Condensed matter physics ,Saturation current ,Heterojunction ,Thermionic emission ,Condensed Matter Physics ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials ,Characterization (materials science) - Abstract
Barrier heights in heterojunctions composed of Nd0.7Sr0.3MnO3 and Nb doped SrTiO3 have been characterized with current–voltage characteristics by using various methods. It is revealed that an inappropriate assumption of the transport mechanism would usually lead to the underestimation of the barrier height. Provided that the transport mechanism is correctly identified the barrier height deduced with current–voltage characteristics could be in accordance with Anderson's model and typical internal photoemission results. It is suggested that for manganite–titanate heterojunctions introducing the ideality factor in the thermionic emission saturation current density equation might largely counteract the underestimation of the barrier height.
- Published
- 2015
218. [Multiplex RT-PCR assay for detecting fusion genes of soft tissue small round cell tumors using paraffin-embedded and formalin-fixed tissue]
- Author
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Yan, Qi, Bin, Chang, Li-juan, Pang, Chun-xia, Liu, Wen-hao, Hu, Hong-an, Li, Jin-fang, Jiang, Jian-feng, Gao, Jing-yu, Wei, and Feng, Li
- Subjects
Paraffin Embedding ,Tissue Fixation ,Base Sequence ,Oncogene Proteins, Fusion ,Proto-Oncogene Protein c-fli-1 ,Reverse Transcriptase Polymerase Chain Reaction ,Molecular Sequence Data ,Soft Tissue Neoplasms ,Sarcoma, Ewing ,Sarcoma, Synovial ,Formaldehyde ,Rhabdomyosarcoma ,Humans ,RNA, Neoplasm ,RNA-Binding Protein EWS - Published
- 2006
219. Studies of Fuel-Air Mixture Explosion Characteristics and Structure Fracture and Damage in Large-Scale Metal Oil Storage Tank
- Author
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Yang Du, Jian Feng Gao, and Xin Sheng Jiang
- Published
- 2006
220. [Changes in inflammatory cascade response and its implication during cerebral ischemia/reperfusion in aged rats]
- Author
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Jian-sheng, Li, Jian-feng, Gao, You-long, Zhou, and Ke, Liu
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Male ,Rats, Sprague-Dawley ,Random Allocation ,Tumor Necrosis Factor-alpha ,Reperfusion Injury ,Age Factors ,Animals ,Vascular Cell Adhesion Molecule-1 ,RNA, Messenger ,Intercellular Adhesion Molecule-1 ,Brain Ischemia ,Rats - Abstract
To investigate the changes in expression of tumor necrosis factor-alpha(TNF-alpha), vascular cellular adhesive molecule-1 (VCAM-1), intercellular adhesion molecular-1 (ICAM-1) and its mRNA expression, and the pathogenetic mechanism of cerebral ischemia/reperfusion(I/R) in elderly.Thirty six male young SD rats (5-6 months old) and 36 male aged SD rats (20-21 months old) were randomly divided into young sham operated group, young model group, aged sham operated group and aged model group, respectively. The two model groups were randomly divided into ischemia 3 hours (I 3 h), I/R 1, 3, 6, 12 days groups. There were 6 rats in each group. Focal cerebral I/R model was replicated with middle cerebral artery occlusion (MCAO). The changes of the nervous dysfunction score, the water content of cerebral constitution and the expression of TNF-alpha, VCAM-1, ICAM-1 and ICAM-1 mRNA were observed at each time point.The expression of TNF-alpha in the aged sham operated group were higher than that of the young sham operated group. The nervous dysfunction score (I 3 h and I/R 1-12 d), the water content of cerebral constitution (I/R 1-6 d), the expression of TNF-alpha (I 3 h and I/R 1-6 d), VCAM-1 (I 3 h and I/R 1 d), ICAM-1 (I 3 h and I/R 1-6 d) and ICAM-1 mRNA (I 3 h and I/R 1-12 d) in young model group and aged model group were higher than those of the young sham operated group and the aged sham operated group respectively. The nervous dysfunction score (I 3 h, I/R 6 d), the expression of TNF-alpha (I/R 1, 3 d), VCAM-1 (I/R 3, 6 d), ICAM-1 (I 3 h, I/R 1 d) and ICAM-1 mRNA (I/R 1-6 d) in aged model group were higher than that of young model group.The cerebral I/R injury is correlated with the up regulation of TNF-alpha, VCAM-1,ICAM-1 and its mRNA expression. The cerebral I/R injury of aged rats is more serious than that of young rats which might be associated with up regulation of TNF-alpha, adhesion molecules expression with aging.
- Published
- 2006
221. Microstructure and Tensile Properties of Hot Worked High Nb Containing TiAl Alloy on Industrial Scale
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Jun Pin Lin, Xiang Jun Xu, Jian Feng Gao, Yan Li Wang, Zhi Lin, and Guo Liang Chen
- Published
- 2005
222. Phytochemical and antiinflammatory studies on Terminalia catappa
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Xinhui Tang, Lizhi Xu, Z.X. Zhang, Yimei Fan, Yaping Wang, Xiaozhi Zhao, and Jian-Feng Gao
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Male ,Anti-Inflammatory Agents ,Fractionation ,Pharmacognosy ,law.invention ,chemistry.chemical_compound ,Mice ,Ursolic acid ,law ,Drug Discovery ,Animals ,Edema ,Pharmacology ,Mice, Inbred ICR ,Chloroform ,biology ,Traditional medicine ,Dose-Response Relationship, Drug ,T-plasminogen activator ,Plant Extracts ,Terminalia ,General Medicine ,biology.organism_classification ,Plant Leaves ,Biochemistry ,chemistry ,Phytochemical ,Acute Disease ,Chronic Disease ,Tetradecanoylphorbol Acetate ,Phytotherapy - Abstract
The antiinflammatory activity of Terminalia catappa leaves ethanolic extract was studied using 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced ear edema in acute and chronic models. A bioassay-oriented fractionation procedure showed that the activity concentrates in the chloroform fraction. Ursolic acid (1) and 2alpha,3beta,23-trihydroxyurs-12-en-28-oic acid (2), isolated from the chloroform fraction, exhibited strong antiinflammatory activities. The results suggest that the triterpenic acids 1 and 2 are responsible for the antiinflammatory activity of T. catappa leaves.
- Published
- 2003
223. Aod1 controlling day 3 thymectomy-induced autoimmune ovarian dysgenesis in mice encompasses two linked quantitative trait loci with opposing allelic effects on disease susceptibility
- Author
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Sandra D. Michael, Randall J. Roper, Jian Feng Gao, Julia E. Biggins, Cory Teuscher, Soo Hong Min, Kenneth S. K. Tung, Stanford B. Call, and Ryan D. McAllister
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Male ,Candidate gene ,Autoimmune Gastritis ,Genetic Linkage ,Mice, Inbred A ,Immunology ,Molecular Sequence Data ,Oophoritis ,Quantitative Trait Loci ,Congenic ,Biology ,Quantitative trait locus ,Cysteine Proteinase Inhibitors ,Autoantigens ,Autoimmune Diseases ,Mice ,Mice, Congenic ,medicine ,Immunology and Allergy ,Animals ,Cystatin A ,Genetic Predisposition to Disease ,IL-2 receptor ,Amino Acid Sequence ,Alleles ,Autoimmune disease ,Genetics ,Antigen Presentation ,Autoantibody ,medicine.disease ,Physical Chromosome Mapping ,Thymectomy ,Cathepsins ,Cystatins ,Mice, Inbred C57BL ,Animals, Newborn ,Female - Abstract
Day 3 thymectomy (D3Tx) leads to a paucity of CD4+CD25+ suppressor T cells, a loss of peripheral tolerance, and the development of organ-specific autoimmune disease in adult mice. Importantly, D3Tx does not lead to autoimmune disease in all mouse strains, indicating that this process is genetically controlled. Previously, we reported linkage of D3Tx-induced autoimmune ovarian dysgenesis (AOD) and its intermediate phenotypes, antiovarian autoantibody responsiveness, oophoritis, and atrophy, to five quantitative trait loci (QTL), designated Aod1 through Aod5. We also showed interaction between these QTL and H2 as well as Gasa2, a QTL controlling susceptibility to D3Tx-induced autoimmune gastritis. To physically map Aod1, interval-specific bidirectional recombinant congenic strains of mice were generated and studied for susceptibility to D3Tx-induced AOD. Congenic mapping studies revealed that Aod1 controls susceptibility to oophoritis and comprises two linked QTL with opposing allelic effects. Aod1a resides between D16Mit211 (23.3 cM) and D16Mit51 (66.75 cM) on chromosome 16. Aod1b maps proximal of Aod1a between D16Mit89 (20.9 cM) and D16Mit211 (23.3 cM) and includes the candidate genes stefin A1, A2, and A3 (Stfa1-Stfa3), inhibitors of cathepsin S, a cysteine protease required for autoantigen presentation, and the development of autoimmune disease of the salivary and lacrimal glands following D3Tx. cDNA sequencing revealed the existence of structural polymorphisms for both Stfa1 and Stfa2. Given the roles of cathepsins in Ag processing and presentation, Stfa1 and Stfa2 alleles have the potential to control susceptibility to autoimmune disease at the level of both CD4+CD25+ suppressor and CD4+CD25− effector T cells.
- Published
- 2003
224. Analysis of the role of Bphs/Hrh1 in the genetic control of responsiveness to pertussis toxin
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Nathan D. Meeker, Takeshi Watanabe, Jian Feng Gao, Parley D. Fillmore, Cory Teuscher, and Stanford B. Call
- Subjects
Blood Glucose ,Bordetella pertussis ,Serotonin ,Epinephrine ,Leukocytosis ,Immunology ,Congenic ,Histamine H1 receptor ,Pertussis toxin ,Microbiology ,Capillary Permeability ,chemistry.chemical_compound ,Mice ,In vivo ,medicine ,Animals ,Genetic Predisposition to Disease ,Hypersensitivity, Delayed ,Receptors, Histamine H1 ,Sensitization ,Mice, Inbred C3H ,biology ,Bacterial Infections ,biology.organism_classification ,Mice, Inbred C57BL ,Infectious Diseases ,medicine.anatomical_structure ,chemistry ,Pertussis Toxin ,Parasitology ,medicine.symptom ,Histamine - Abstract
In vivo intoxication withBordetella pertussistoxin (PTX) elicits a variety of physiological responses including a marked leukocytosis, disruption of glucose regulation, adjuvant activity, alterations in vascular function, hypersensitivity to vasoactive agents, and death. We recently identifiedBphs, the locus controlling PTX-induced hypersensitivity to the vasoactive amine histamine, as the histamine H1receptor (Hrh1). In this studyBphscongenic mice and mice with a disruptedHrh1gene were used to examine the role ofBphs/Hrh1in the genetic control of susceptibility to a number of phenotypes elicited following in vivo intoxication. We report that the contribution ofBphs/Hrh1to the overall genetic control of responsiveness to PTX is restricted to susceptibility to histamine hypersensitivity and enhancement of antigen-specific delayed-type hypersensitivity responses. Furthermore, the genetic contribution ofBphs/Hrh1to vasoactive amine sensitization is specific for histamine, since hypersensitivity to serotonin was unaffected byBphs/Hrh1. Bphs/Hrh1also did not significantly influence susceptibility to the lethal effects, the leukocytosis response, disruption of glucose regulation, and histamine-independent increases in vascular permeability associated with in vivo intoxication. Nevertheless, significant interstrain differences in susceptibility to the lethal effects of PTX and leukocytosis response were observed. These results indicate that the phenotypic variation in responsiveness to PTX reflects the genetic control of distinct intermediate phenotypes rather than allelic variation in genes controlling overall susceptibility to intoxication.
- Published
- 2003
225. Corrigendum to 'Neoproterozoic chromite-bearing high-Mg diorites in the western part of the Jiangnan orogen, southern China: Geochemistry, petrogenesis and tectonic implications' [Lithos 200–201 (2014) 35–48]
- Author
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Jin-Cheng Zhou, Liang Qi, Xin Chen, Xu-Jie Shu, Jian-Feng Gao, Di Wang, and Xiao-Lei Wang
- Subjects
Tectonics ,Lithos ,Southern china ,Geochemistry and Petrology ,Geochemistry ,Geology ,Chromite ,Petrology ,Petrogenesis - Published
- 2014
226. Induction of interferon-λ contributes to TLR3 and RIG-I activation-mediated inhibition of herpes simplex virus type 2 replication in human cervical epithelial cells.
- Author
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Li Zhou, Jie-Liang Li, Yu Zhou, Jin-Biao Liu, Ke Zhuang, Jian-Feng Gao, Shi Liu, Ming Sang, Jian-Guo Wu, and Wen-Zhe Ho
- Published
- 2015
- Full Text
- View/download PDF
227. Evaluation of sample dissolution method for Sm-Nd isotopic analysis of scheelite
- Author
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Zhu-Yin Chu, Liang Qi, Jian-Feng Gao, Lei Chen, Yue-Heng Yang, Jinghui Guo, and Xiao-Chun Li
- Subjects
Isotope ,Chemistry ,Inorganic chemistry ,Crystal structure ,Isotope dilution ,Decomposition ,Analytical Chemistry ,chemistry.chemical_compound ,Scheelite ,Tungstic acid ,Dissolution ,Spectroscopy ,Nuclear chemistry ,Isotope analysis - Abstract
Sm-Nd isotope systematics of scheelite is becoming a powerful geochronometer for dating the Au and W ore deposits. However, Sm-Nd isotopic analysis of scheelite is relatively difficult due to the formation of large amounts of tungstic acid (H2WO4) precipitates during the conventional acid decomposition of scheelite. In this study, both the low temperature attack and Teflon bomb acid dissolution methods for Sm-Nd isotope analysis of scheelite have been thoroughly investigated. It has been shown that, for both low temperature attack and Teflon bomb methods, although a large amount of tungstic acid precipitate remains during the 2.5 M HCl acidification process prior to cation exchange separation, only less than 10% of the Sm and Nd remains in the tungstic acid precipitate. On the other hand, it has been found that, for isotope dilution analysis, the spike-sample isotopic equilibration was only completely achieved for the Teflon bomb method and not completely achieved for the low temperature attack method, indicating that the low temperature attack method has possibly not liberated all the rare earth elements (REEs) from the scheelite crystal structure. Consequently, for high precision scheelite Sm-Nd dating purposes, the complex Teflon bomb rather than the simple low temperature attack method should be used in order to completely digest scheelite samples; alternatively, since it has been found that the tungstic acid precipitate formed during the acid dissolution process can be completely dissolved by self-purified low-blank 30% NaOH, a simple low temperature attack method combined with low-blank 30% NaOH dissolution of the remaining tungstic acid precipitate can also possibly be used to completely dissolve the scheelite sample for Sm-Nd isotopic analysis.
- Published
- 2012
228. Synthesis of -Fe2O3 nanoparticles by homogeneous co-precipitation method
- Author
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Jian-Feng Gao and Zhi-Gang Wu
- Subjects
Chemistry ,Biomedical Engineering ,Iron oxide ,Analytical chemistry ,Maghemite ,Nanoparticle ,Infrared spectroscopy ,Bioengineering ,engineering.material ,Condensed Matter Physics ,Ferrous ,chemistry.chemical_compound ,X-ray crystallography ,engineering ,medicine ,Ferric ,General Materials Science ,Saturation (magnetic) ,medicine.drug - Abstract
Pure maghemite (γ-Fe 2 O 3 ) nanoparticles were prepared via so-called homogeneous co-precipitation method using urea and ammonia as precipitation agent for ferrous and ferric ions at ambient temperature. X-ray diffraction, energy dispersive spectrometer and Fourier transform infrared spectrophotometer revealed that the obtained product was pure γ-Fe 2 O 3 . Transmission electron microscope investigations showed the morphology of the nanoparticles were of approximate spherical shape with an average diameter of 11 nm. Magnetic measurements showed that resulting iron oxide nanopowder exhibited a characteristic ferromagnetism with a maximum saturation magnetisation of 66.83 emu/g.
- Published
- 2012
229. An improved digestion technique for determination of platinum group elements in geological samples
- Author
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Xiao-Wen Huang, Mei-Fu Zhou, Jing Hu, Liang Qi, Jian-Feng Gao, and Hong Zhong
- Subjects
Peridotite ,Materials science ,Certified reference materials ,Ultramafic rock ,Metallurgy ,Hot plate ,Platinum group ,Tailings ,Spectroscopy ,Analytical Chemistry - Abstract
This paper reports a modified digestion method for the determination of platinum group elements (PGEs) in geological samples. Samples are first digested by HF in a custom made 120 ml PTFE beaker on a hot plate to remove silicates. The dried residue is then digested with HF + HNO3 at 190 °C for about 48 h after the beaker is sealed in a stainless steel pressure bomb. Although only HF + HNO3 are used for sample digestion at relatively low temperature, ultramafic rocks with refractory minerals can be effectively decomposed by this method. Analytical results for CCRMP (CANMET, Ottawa, Canada) certified reference materials WGB-1 (gabbro), UMT-1 (ultramafic ore tailings), WPR-1 (peridotite) and WMS-1(Massive Sulphide), agree well with the certified values. The proposed method significantly simplifies the sample digestion procedures for PGE analysis compared to those used previously.
- Published
- 2011
230. An improved Carius tube technique for determination of low concentrations of Re and Os in pyrites
- Author
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Jian-Feng Gao, Zheng Zhao, Mei-Fu Zhou, and Liang Qi
- Subjects
Radiochemistry ,Mineralogy ,engineering.material ,Hydrothermal circulation ,Analytical Chemistry ,law.invention ,Matrix (chemical analysis) ,chemistry.chemical_compound ,chemistry ,law ,Molybdenite ,engineering ,Aqua regia ,Tube (fluid conveyance) ,Pyrite ,Ion-exchange resin ,Distillation ,Spectroscopy - Abstract
A simple and highly selective analytical method is developed for Re–Os dating in hydrothermal pyrites. Pyrites were first digested with HNO3 in a 120 ml Carius tube. The released additional gas and a small portion of volatile Os (∼6% of total Os) were collected by 10 mol l−1 of HCl in an ice-water bath. After the sulfides were totally reacted with HNO3, the HCl solution containing all the released Os was transferred back to the Carius tube. The sample was further digested in aqua regia at 200 °C for about 10 h in a sealed Carius tube. Because prior digestion in an open Carius tube removed the additional gas, this improved technique allows increasing the sample mass to about 3 g, which is vital for Re–Os dating in Re and Os poor hydrothermal pyrites. Os was separated from the matrix by distillation and Re by anion exchange resin. The results obtained for molybdenite reference materials, JDC and HLP mixed with 3 g pyrite are in good agreement with certified values. Despite very low concentrations of Re and Os, the pyrite yields excellent repeatability and can be used for Re and Os poor hydrothermal pyrites.
- Published
- 2010
231. Influence of spacer layer thickness on the current-voltage characteristics of pseudomorphic AlAs/In 0.53 Ga 0.47 As/In As resonant tunnelling diodes
- Author
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Yang, Zhang, primary, Chun-Lin, Han, additional, Jian-Feng, Gao, additional, Zhan-Ping, Zhu, additional, Bao-Qiang, Wang, additional, and Yi-Ping, Zeng, additional
- Published
- 2008
- Full Text
- View/download PDF
232. Central Histamine H3 Receptor Signaling Negatively Regulates Autoimmune Inflammation (129.31)
- Author
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Cory Teuscher, Meena Subramanian, Rajkumar Noubade, Jian Feng Gao, Halina Offner, James F. Zachary, and Elizabeth P. Blankenhorn
- Subjects
Immunology ,Immunology and Allergy - Abstract
Histamine is a ubiquitous regulator of diverse physiologic processes including inflammation, immune modulation and neurotransmission. Four subtypes of histamine receptors are currently recognized and genetic and pharmacological studies have shown that the H1 and H2 receptors play a role in susceptibility to experimental allergic encephalomyelitis (EAE), the primary autoimmune model of multiple sclerosis. Histamine H3 receptor (H3R), which is not expressed in hematopoietic cells, is a presynaptic auto- and hetero-receptor. Here we show that H3RKO mice develop significantly more severe acute phase clinical disease and neuropathology compared to wild-type controls. In H3RKO mice this is preceded by disruption of the blood brain barrier and increased chemokine/chemokine receptor expression in peripheral T-cells. These data are consistent with inhibition of H3R-mediated neurogenic control of cerebrovascular tone and T-cell function. Additionally, genetic studies indicate that an H3R polymorphism leading to differential expression of H3R isoforms underlies eae8, a locus controlling disease associated weight loss, a phenotype known to be regulated by central H3R activity.
- Published
- 2007
233. Isotopic geochemistry of the Xiwang uranium deposit in Wengyuan, China
- Author
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Jian-Feng Gao, Jianjun Lu, and Weizhou Shen
- Subjects
Geochemistry and Petrology ,Geochemistry ,China ,Geology ,Uranium deposit - Published
- 2006
234. Surface erosion of pyrite by Thiobacillus ferrooxidans
- Author
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Juan Li, Jian-Feng Gao, and Jianjun Lu
- Subjects
Thiobacillus ferrooxidans ,Geochemistry and Petrology ,Chemistry ,Metallurgy ,Erosion ,engineering ,Pyrite ,engineering.material - Published
- 2006
235. Geochemistry of cretaceous mafic dykes in North Guangdong, China
- Author
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Jianjun Lu, Hong-Fei Ling, Weizhou Shen, and Jian-Feng Gao
- Subjects
Geochemistry and Petrology ,Geochemistry ,Mafic ,China ,Cretaceous ,Geology - Published
- 2006
236. Comment on 'Molybdenum Isotope Evidence for Widespread Anoxia in Mid-Proterozoic Oceans'
- Author
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Kui-Dong Zhao, H.-F. Ling, Shao-Yong Jiang, Jian-Feng Gao, and D.-S. Ma
- Subjects
Molybdenum isotope ,Multidisciplinary ,Oceanography ,Isotope ,Proterozoic ,Geochemistry ,Black sea ,Sedimentation ,Oil shale ,Geology - Abstract
Arnold et al . ([ 1 ][1]) reported Mo isotope compositions of mid-Proterozoic black shale, which were different from those of euxinic sediments in the Black Sea. On the basis of a mass balance model calculation, they claimed that “the area of oxic sedimentation in the mid-Proterozoic oceans was
- Published
- 2005
237. TolC Promotes ExPEC Biofilm Formation and Curli Production in Response to Medium Osmolarity.
- Author
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Bo Hou, Xian-Rong Meng, Li-Yuan Zhang, Chen Tan, Hui Jin, Rui Zhou, Jian-Feng Gao, Bin Wu, Zi-Li Li, Mei Liu, Huan-Chun Chen, Ding-Ren Bi, and Shao-Wen Li
- Abstract
While a high osmolarity medium activates Cpx signaling and causes CpxR to repress csgD expression, and efflux protein TolC protein plays an important role in biofilm formation in Escherichia coli, whether TolC also responds to an osmolarity change to regulate biofilm formation in extraintestinal pathogenic E. coli (ExPEC) remains unknown. In this study, we constructed ΔtolC mutant and complement ExPEC strains to investigate the role of TolC in the retention of biofilm formation and curli production capability under different osmotic conditions. The ΔtolC mutant showed significantly decreased biofilm formation and lost the ability to produce curli fimbriae compared to its parent ExPEC strain PPECC42 when cultured in M9 medium or 1/2 M9 medium of increased osmolarity with NaCl or sucrose at 28°C. However, biofilm formation and curli production levels were restored to wild-type levels in the ΔtolC mutant in 1/2M9medium. We propose for the first time that TolC protein is able to formbiofilm even under high osmotic stress. Our findings reveal an interplay between the role of TolC in ExPEC biofilm formation and the osmolarity of the surrounding environment, thus providing guidance for the development of a treatment for ExPEC biofilm formation. [ABSTRACT FROM AUTHOR]
- Published
- 2014
- Full Text
- View/download PDF
238. Sulfide Saturation and Magma Emplacement in the Formation of the Permian Huangshandong Ni-Cu Sulfide Deposit, Xinjiang, Northwestern China.
- Author
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JIAN-FENG GAO, MEI-FU ZHOU, LIGHTFOOT, PETER C., YAN WANG, CHRISTINA, LIANG QI, and MIN SUN
- Subjects
SULFIDES ,CHALCOGENIDES ,MAGMAS ,IGNEOUS rocks ,NICKEL compounds - Abstract
The eastern Tianshan orogenic belt, northwestern China, hosts ~120 mafic-ultramafic intrusions and at least six of them host significant Ni-Cu sulfide mineralization of which the Permian Huangshandong intrusion is the largest. The mafic-ultramafic rocks of the Huangshandong intrusion comprise lherzolite, gabbronorite, gabbro, and diorite. Individual orebodies are composed of pyrrhotite, pentlandite, and chalcopyrite as disseminated to net-textured or massive to semimassive sulfide mineralization. Oxide-bearing sulfide mineralization contains 1 to 5% magmatic magnetite that has ilmenite and spinel exsolution lamellae. Silicate rocks and sulfide mineralization have variable whole-rock platinum group elements (PGE; 0.38-362 ppb), Cu (42-97,000 ppm), and Ni (26-33,000 ppm) concentrations. The mineralization is broken out into two types termed oxide rich and oxide poor. The oxide-rich sulfide mineralization has high PGE concentrations with low
187 Re/188 Os ratios (38.9-151), whereas oxide-poor sulfide mineralization has low PGE concentrations with high187 Re/188 Os (159-781). Both oxide-rich and -poor sulfide mineralization have highly variable γOs values (49-189 and 30-278, respectively). Oxide-rich sulfide mineralization contains magnetite with variable amounts of MgO, TiO2 , Al2 O3 , FeOtotal , Cr, V, Zn, and Sn, indicating that they crystallized from different stages during magma differentiation. We propose that the host intrusion and associated sulfide mineralization were derived from high Mg basaltic magmas from a mantle source that was previously modified by subducted oceanic slab. Oxide-poor sulfide mineralization of the Huangshandong intrusion formed from a magma that underwent <0.03% sulfide removal before emplacement and was thus PGE depleted. Oxide-rich sulfide mineralization formed from magma that had much lower amounts of sulfide (<0.003%) removed in the early stage before entering the Huangshandong magma chamber. An early sulfide saturation event was likely associated with fractionation of silicate minerals in a deep-staging magma chamber. The second sulfide saturation event that formed the sulfide mineralization was probably triggered by selective crustal contamination and fractionation in the high-level chamber where mixing of magmas and accumulation of immiscible sulfide occurred. [ABSTRACT FROM AUTHOR]- Published
- 2013
- Full Text
- View/download PDF
239. Sm-Nd dating and Nd-Sr isotopic characteristics of the Shimian ophiolite suite, Sichuan Province
- Author
-
Zhusheng Yang, Weizhou Shen, Qiwen Yang, Shijin Xu, and Jian-Feng Gao
- Subjects
Isochron ,Multidisciplinary ,Gabbro ,Back-arc basin ,Geochemistry ,Structural basin ,Ophiolite ,Geology ,Hydrothermal circulation ,Mantle (geology) - Abstract
By measuring the Sm-Nd and Rb-Sr isotopic compositions of harzburgite and gabbro from Shimian ophiolite suite, we got the whole rock Sm-Nd isochron age of (938±30) Ma (2σ), and the eNd of 7.6±0.8 (2σ), which shows that the ophiolite was formed at the Early Neoproterozoic. The obvious change (0.70209–0.70708) of ISr values of the ophiolite is caused by the meteoric hydrothermal alteration. The high eNd values indicate that the primitive magma was derived from the intense depleted mantle reservoir. It is suggested that this area was in a back-arc basin environment during the Early Neoproterozic.
- Published
- 2002
240. A simple and easy method for cultivation of avian pulmonary microvascular endothelial cells.
- Author
-
Jian-feng, GAO, Ke-rong, ZHANG, Xiao-dong, LIU, Ding, ZHANG, Li-ru, ZHAO, and Jia-kui, LI
- Published
- 2013
241. Origin of PGE-Poor and Cu-Rich Magmatic Sulfides from the Kalatongke Deposit, Xinjiang, Northwest China.
- Author
-
Jian-Feng Gao, Mei-Fu Zhou, Lightfoot, Peter C., Yan Wang, Christina, and Liang Qi
- Subjects
SULFIDES ,OROGENIC belts ,SULFIDE ores ,SEDIMENTARY rocks - Abstract
The Kalatongke Cu-Ni sulfide deposit in the Paleozoic Altay orogenic belt, NW China, is hosted in a Permian mafic intrusion consisting of norite, troctolite, gabbro, and diorite. Disseminated Ni-Cu, massive Ni-Cu, and massive Cu-rich sulfide ores are mainly hosted in norite and gabbro. Some massive Ni-Cu ores also occur in the Carboniferous sedimentary rocks. The geologic and compositional relationships between various sulfide ores and the rocks of Kalatongke offer a new interpretation of the sequence of emplacement of the magmas, which underpins an understanding of die compositions of the ores and the formation of the Kalatongke deposit. Olivine grains from disseminated Ni-Cu ores have Fo values ranging from 71.6 to 78.0 mol 98 and Ni contents from 1.000 to 2,200 ppm. Typically, Ni decreases from the cores to the rims from 2.000 to 1,000 ppm at constant Fo content, indicating the reaction of early-formed olivine with later-segregated sulfide melt. Cr spinels at Kalatongke are highly enriched in Fe
3+ and Fe2+ , with relatively low Cr, Al, and Ti, reflecting reaction with evoked trapped intercumulus melt. Norites are depleted in Nb, Ta, Zr, Hf, and Th and enriched in Sr and Ba, whereas disseminated Ni-Cu sulfide ores have considerable depletion of Kb and enrichment of Sr and Ba and lack depletion of Nb, Ta, Zr, and Hf, indicating their different origins. Disseminated Ni-Cu sulfide ores have bulk compositions with variable Cu and Ni contents which are much lower than those of massive Cu-rich and Ni-Cu ores, but disseminated and massive Ni-Cu ores have similar PCE contents with relatively low Pd/Ir ratios. Massive Cu-rich ores have much higher Pd and Pt with very high Pd/Ir ratios. The Kalatongke Cu-Ni sulfide deposit appears to have formed from two different pulses of PGE-poor and Cu-rich basaltic magmas that underwent different degrees of assimilation and fractional crystallization. The first magma pulse gained sulfide saturation because of minor crystal contamination and fractionated a small amount of sulfide (<0.03%); the evolved melt then intruded and assimilated crystal materials to attain sulfide saturation again. Sulfide liquid segregated from the magma to form the massive sulfide melts and residual magma formed the noritic rocks in the shallow magma chamber. The segregated massive sulfide melts then underwent further fractionation to form massive Ni-Cu and massive Cu-rich ores. The second pulse of magma after removal of sulfides (<0.02%) experienced more crystal contamination and re attained S saturation. This new S-saturated and phenocryst-laden magma intruded the earlier formed massive sulfide ores and norites and formed the disseminated sulfide ores. [ABSTRACT FROM AUTHOR]- Published
- 2012
- Full Text
- View/download PDF
242. Central histamine H3 receptor signaling negatively regulates susceptibility to autoimmune inflammatory disease of the CNS.
- Author
-
Teuscher, Cory, Subramanian, Meena, Noubade, Rajkumar, Jian Feng Gao, Offner, Halina, Zachary, James F., and Blankenhorn, Elizabeth P.
- Subjects
HISTAMINE ,BLOOD-brain barrier ,MULTIPLE sclerosis ,ENCEPHALOMYELITIS ,NEUROLOGICAL disorders ,T cells ,LABORATORY mice - Abstract
Histamine (HA), a biogenic amine with a broad spectrum of activities in both physiological and pathological settings, plays a key regulatory role in experimental allergic encephalomyelitis, the autoimmune model of multiple sclerosis. HA exerts its effect through four G protein-coupled receptors designated HA receptor H
1 , H2 , H3 , and H4 . We report here that, compared with wild-type animals, mice with a disrupted HA H3 receptor (H3RKO), the expression of which is normally confined to cells of the nervous system, develop more severe disease and neuroinflammation. We show that this effect is associated with dysregulation of blood-brain barrier permeability and increased expression of MIP-2, IP-10, and CXCR3 by peripheral T cells. Our data suggest that pharmacological targeting of the H3 R may be useful in preventing the development and formation of new lesions in multiple sclerosis, thereby significantly limiting the progression of the disease. [ABSTRACT FROM AUTHOR]- Published
- 2007
- Full Text
- View/download PDF
243. Heterogeneous mantle source and magma differentiation of quaternary arc-like volcanic rocks from Tengchong, SE margin of the Tibetan Plateau
- Author
-
Jian-Feng Gao, Christina Yan Wang, Mei-Fu Zhou, Paul T. Robinson, Jun-Hong Zhao, Dan-Ping Yan, and John Malpas
- Subjects
Basalt ,geography ,geography.geographical_feature_category ,Olivine ,Volcanic arc ,Subduction ,Geochemistry ,engineering.material ,Mantle (geology) ,Volcanic rock ,Geophysics ,Geochemistry and Petrology ,engineering ,Phenocryst ,Geology ,Trachybasalt - Abstract
The Tengchong volcanic field north of the Burma arc comprises numerous Quaternary volcanoes in the southeastern margin of the Tibetan Plateau. The volcanic rocks are grouped into four units (1–4) from the oldest to youngest. Units 1, 3 and 4 are composed of olivine trachybasalt, basaltic trachyandesite and trachyandesite, and Unit 2 consists of hornblende dacite. The rocks of Units 1, 3, and 4 form a generally alkaline suite in which the rocks plot along generally linear trends on Harker diagrams with only slight offset from unit to unit. They contain olivine phenocrysts with Fo values ranging from 65 to 85 mol% and have Cr-spinel with Cr# ranging from 23 to 35. All the rocks have chondrite-normalized REE patterns enriched in LREE and primitive mantle-normalized trace element patterns depleted in Ti, Nb and Ta, but they are rich in Th, Ti and P relative to typical arc volcanics. Despite minor crustal contamination, 87Sr/86Sr ratios (0.706–0.709), eNd values (−3.2 to −8.7), and eHf values (+4.8 to −6.4) indicate a highly heterogeneous mantle source. The Pb isotopic ratios of the lavas (206Pb/204Pb = 18.02–18.30) clearly show an EMI-type mantle source. The underlying mantle source was previously modified by subduction of the Neo-Tethyan oceanic and Indian continental lithosphere. The present heterogeneous mantle source is interpreted to have formed by variable additions of fluids and sediments derived from the subducted Indian Oceanic lithosphere, probably the Ninety East Ridge. Magma generation and emplacement was facilitated by transtensional NS-trending strike-slip faulting.
- Full Text
- View/download PDF
244. Electroresistance and field effects in epitaxial thin films of Pr0.7Sr0.3MnO3
- Author
-
H. Y. Liu and Jian-Feng Gao
- Subjects
Materials science ,Condensed matter physics ,Magnetoresistance ,Chemistry(all) ,Transition temperature ,Field effect ,General Chemistry ,Manganite ,Materials Science(all) ,Electrical resistivity and conductivity ,General Materials Science ,Thin film ,Electric current ,Single crystal - Abstract
Highly epitaxial thin films of Pr0.7Sr0.3MnO3 were grown on (100) SrTiO3 single crystal substrates by laser ablation. Similar to other manganite compounds, these Pr0.7Sr0.3MnO3 films exhibited remarkable magnetoresistance. Application of electric currents could induce a remarkable reduction in resistivity, demonstrating a strong electroresistance effect. The ratio of the resistance variation, ER=[R(0)−R(I)]/R(I), is about 33% at metal-insulator transition temperature. Using a planar field effect configuration, significant field modulation of the metal-insulator transition was achieved. The observed field effects were discussed based on the strong interactions between carrier spins and localized spins in Mn ions, as well as the percolative mechanism of phase separation.
- Full Text
- View/download PDF
245. Geology setting and metallogenesis of the Alta Floresta Province, southern Amazon Craton (Brazil)
- Author
-
Veronica Trevisan, Roberto Xavier, Steffen Hagemann, Anthony Kemp, Robert Loucks, Jian-Feng Gao, Rafael Rodrigues de Assis, and Antônio João Paes de Barros
246. Mafic-ultramafic intrusion formed by multi-stage evolution of hydrous basaltic melts.
- Author
-
Qi-Wei Li, Jun-Hong Zhao, Mei-Fu Zhou, and Jian-Feng Gao
- Subjects
- *
RARE earth metals , *SECONDARY ion mass spectrometry , *IGNEOUS rocks , *HYDROUS , *GABBRO , *SIDEROPHILE elements - Abstract
The magmatic processes beneath the active continental margins are very complicated and affect structures and compositions of the arc roots. Neoproterozoic igneous rocks are widely distributed around the margins of the Tarim Block in NW China. The Xingdier mafic-ultramafic intrusion is a composite body, located at the northern margin of the Tarim Block, and consists of gabbro, pyroxenite, and peridotite units. The gabbro unit has a secondary ion mass spectrometry zircon U-Pb age of 727 ± 5 Ma. Rocks from the Xingdier intrusion have a large range of MgO (12.9--32.8 wt%) and SiO2 (43.0-57.9 wt%), and low K2O + Na2O (0.11-2.25 wt%) contents. They have right inclined chondrite-normalized rare earth element patterns with (La/Yb)N ratios of 2.2-8.6. Their primitive mantle normalized trace element patterns show arc-affinity geochemical features characterized by enrichment in Rb, Ba, Th, U, and Pb and depletion in Nb, Ta, and Ti. They have variable initial 87Sr/86Sr ratios (0.7063-0.7093), εNd(t) values (-2.9 to -7.8), 206Pb/204Pb (17.08-17.80), 207Pb/204Pb (15.42-15.49), and 208Pb/204Pb ratios (37.48-38.05), forming an evolution trend from the peridotite unit to the gabbro and pyroxenite units. Clinopyroxene in the three units is chemically similar to those formed in hydrous magmas. The spinel inclusions in olivine from the peridotite unit show unmixing texture and have high Al contents and oxygen fugacity of ~FMQ+1. Therefore, the parental magma was probably derived from a lithospheric mantle enriched by slab-derived fluids. Rocks from the gabbro and peridotite units are proposed to have been derived from olivine-normative melts, whereas rocks from the pyroxenite unit are cumulates from the quartz-normative melts. Such contrasting parental magmas resulted from variable degrees of crustal contamination and fractional crystallization in the arc root. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
247. Determination of components in Radix paeoniae rubra based on QAMS.
- Author
-
Ling-Feng Y, Xiao-Wei H, Jian-Feng G, Lian Z, Dong-Mei W, Ji-Kai S, Zhi-Guo Z, Jing-Han W, Jun L, Yu-Mei W, Qi L, Hong-Jun L, Yue-Yu L, and Yan L
- Subjects
- Benzoic Acid, Bridged-Ring Compounds, Chromatography, High Pressure Liquid methods, Gallic Acid, Monoterpenes, Snails, Catechin, Drugs, Chinese Herbal, Paeonia chemistry
- Abstract
The current study aimed to establish simple and quick quality evaluation method of Chishao based on QAMS. Oxypaeoniflorin is used as a marker in the Chishao root. Based on it, the content of other components could be obtained by establishing the mathematical relationship. UPLC method was used to collect data, and the detection wavelengths were 230nm (benzoic acid, paeoniflorin), 263nm (hydroxy paeoniflorin) 274nm (gallic acid, paeoniflorin, catechin), respectively. The stationary phase was an Agilent ZORBAX SB-C
18 and the mobile phase was acetonitrile -0.1% formic acid-water. The gradient elution method was adopted at the certain flow rate (0.3 mL/min). The column temperature set 40o C, and the injection volume was 1μL. Multiple reaction monitoring mode was selected for data collection. The linear ranges of benzoic acid, paeoniflorin, hydroxy-paeoniflorin, gallic acid, catechin and paeoniflorinhad good linearity (r ≥0.9995). The UPLC method was established to determine the content of paeoniflorin, benzoic acid, catechin, gallic acid, paeoniflorin, andhydroxy-paeoniflorin in Radix Paeoniae Rubra. In the current study, the method for the chemical components in Radix Paeoniae Rubra to provide the evaluation basis of medicinal effects.- Published
- 2022
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