Yang Li

Jiangsu University, Chenkiang, Jiangsu Sheng, China

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Publications (11)

  • Kaibin Zhang · Jing Shi · Yang Li · [...] · Jianchao Gui
    [Show abstract] [Hide abstract] ABSTRACT: The purpose of this study was to establish a partial-thickness articular cartilage defects model in adult rats and explore the respond of chondrogenic cells to the cartilage injury. Forty-five adult Sprague-Dawley rats were divided into operated group, sham-operated group and control group. Partial-thickness cartilage defects were created on the weight-bearing region of femoral condyles by a converted ophthalmic knife. Rats were exposed to 5-bromo-2'-deoxyuridine (BrdU) for five consecutive days and were sacrificed 1, 2 and 4 weeks after surgery. Evaluations of macroscopic and histological changes were made. Chondrocyte apoptosis was evaluated by TUNEL assay. Immunofluorescence staining of CD105 and BrdU, double staining of CD105/integrin α5β1 and CD105-positive cells counting were performed for evaluations of cells around the defects. Cartilage softening and fibrillation with chondrocyte apoptosis were observed around the injury site after surgery. Results of histological scores indicated no significant difference between one time point and a successive time point for either group. CD105-positive cells and BrdU-label-retaining cells were observed around the linear injury. And cells counting showed the number of CD105-positive cells increased at later time points (P < 0.05). Immunofluorescence double staining demonstrated co-localization of CD105 and integrin α5β1 in activated cells around the defects. We establish a partial-thickness cartilage defects model in adult rats and demonstrate this injury may lead to activation of putative progenitor cells. In addition, the activated cells express integrin α5β1 specially, which may help in early discovery of osteoarthritis.
    Article · Mar 2016 · Journal of Molecular Histology
  • Yang Li · Jianxin Zhou · Xiaofei Yang · [...] · Jianchao Gui
    [Show abstract] [Hide abstract] ABSTRACT: The objective of this study was to explore the effects of intermittent hydrostatic pressure (IHP) on the chondrogenic differentiation of cartilage progenitor cells (CPCs) cultivated in alginate beads. CPCs were isolated from the knee joint cartilage of rabbits, and infrapatellar fat pad-derived stem cells (FPSCs) and chondrocytes (CCs) were included as the control cell types. Cells embedded in alginate beads were treated with IHP at 5 Mpa and 0.5 Hz for 4 h/day for 1, 2, or 4 weeks. The cells' migratory and proliferative capacities were evaluated using the scratch and Live/Dead assays, respectively. Hematoxylin and eosin staining, safranin O staining, and immunohistochemical staining were performed to determine the effects of IHP on the synthesis of extracellular matrix (ECM) proteins. Real-time polymerase chain reaction analysis was performed to measure the expression of genes related to chondrogenesis. The scratch and Live/Dead assays revealed that IHP significantly promoted the migration and proliferation of FPSCs and CPCs to different extents. The staining experiments showed greater production of cartilage ECM components (glycosaminoglycans and collagen II) by cells exposed to IHP, and the gene expression analysis demonstrated that IHP stimulated the expression of chondrocyte-related genes. Importantly, these effects of IHP were more prominent in CPCs than in FPSCs and CCs. Considering all of our experimental results combined, we conclude that CPCs demonstrated a stronger chondrogenic differentiation capacity than the FPSCs and CCs under stimulation with IHP. Thus, the use of CPCs, combined with mechanical stimulation, may represent a valuable strategy for cartilage tissue engineering.
    Article · Jan 2016 · Development Growth and Regeneration
  • [Show abstract] [Hide abstract] ABSTRACT: The incorporation of noble metals into semiconductors has been proven to be effective for the construction of highly efficient composite photocatalytic systems. In this work, the Ag/graphitic carbon nitride (g-C3N4) composite was in-situ fabricated by combining the coordination-driven assembly of precursors and calcination process. The interactions between precursors favor the formation of well-defined rod-like Ag-containing complex intermediates, the subsequent annealing of the obtained intermediates produces the Ag/g-C3N4 composite catalysts with improved photodegradation of rhodamine B (RhB). Although the composite differs in the morphology and nitrogen-containing precursor, the role of generated Ag component in the Ag/g-C3N4 composite is considered to be crucial for the enhancement both in light-harvesting ability and photocatalytic activity owing to its unique surface plasmonic effects. Holes and radicals trapping experiments imply that photo-induced active holes and superoxide radicals are predominant under visible light irradiation and make major contributions to improved photocatalytic performance. The finding provides an opportunity to design and in-situ synthesize noble metal-doped semiconductor heterojunctions for potential applications in photocatalysis, photovoltaic and photoelectronic devices.
    Article · Dec 2015
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    [Show abstract] [Hide abstract] ABSTRACT: In this work, bifunctional TiO2/Ag3PO4/graphene (GR) composites have been prepared via the combination of ion-exchange method and hydrothermal approach, and the fabrication of “pizza-like” three-phase TiO2/Ag3PO4/GR composites has been achieved through the electrostatic-driven assembly of positively-charged Ag+ on negatively-charged graphene oxide (GO) sheets, followed by the nucleation & controlled growth of Ag3PO4 and the deposition of Degussa P25 on the GO surface. Consequently, the hydrothermal treatment leads to the generation of TiO2/Ag3PO4/GR composites with well-defined structures. The as-prepared composites exhibited highly efficient visible light photocatalytic activity toward organic dye molecule degradation and showed excellent bactericidal performance. This is the first report on the production of bifunctional three-phase metal oxide-Ag3PO4-GR composite materials with improved photocatalytic and antibacterial properties. The improved photocatalytic activity is attributed to the effective separation of photoexcited electron-hole pairs and fast charge transfer between components in the composite, while its excellent bactericidal performance is believed to come from intrinsic bacterial inactivation of Ag3PO4 and photo-induced antibacterial activity of active oxygen-containing radicals generated in the irradiated system. The proper molar ratio of Ag3PO4/TiO2 and the added amount of GO in the precursor have been considered to play crucial roles in the formation of bifunctional composites with promising properties. The TiO2/Ag3PO4/GR composite significantly decreases the percentage of expensive Ag-containing material while it reveals better photocatalytic and antibacterial performance than Ag3PO4, providing new insights into the low-cost, large-scale production of Ag3PO4-based function materials for practical applications.
    Full-text Article · Apr 2014 · RSC Advances
  • [Show abstract] [Hide abstract] ABSTRACT: Cubic Ag3PO4 microcrystals were synthesized by deposition-precipitation in the presence of ammonia. As-synthesized samples were characterized by field emission scanning electron microscopy (FE-SEM), X-ray diffraction (XRD), Raman spectroscopy and UV-visible diffuse reflectance spectroscopy (UV-vis DSR). Visible-light-driven photocatalytic performance of the obtained Ag3PO4 was evaluated for photocatalytic degradation of typical organic dye molecules. Compared to irregular Ag3PO4 materials prepared in the absence of ammonia, the prepared cubic samples exhibited a higher photocatalytic activity, suggesting the crucial role of the ammonia in the formation of cubic Ag3PO4 microcrystals. In addition, the specific cubic morphology of Ag3PO4 sample contributes substantially to its highly efficient visible light photocatalytic performance. Moreover, photocatalytic degradation experiments of the cubic Ag3PO4 toward different organic dye molecules rhodamine B (RhB), methyl blue (MB) and methyl orange (MO) were carried out. These results show that photo-generated active oxygen-containing superoxide radicals and photo-induced holes offer the major contribution to highly efficient visible light photocatalytic activity of Ag3PO4.
    Article · Dec 2013 · Ceramics International
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    Xiaofei Yang · Jieling Qin · Yang Li · [...] · Hua Tang
    [Show abstract] [Hide abstract] ABSTRACT: Graphene (GR)-TiO2 mesocrystal composites were prepared by a facile template-free process based on the combination of sol-gel and solvothermal methods, and were characterized using field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), X-ray diffraction (XRD), Raman spectroscopy, UV-vis diffuse reflectance spectroscopy (UV-vis DRS), nitrogen absorption and electron spin resonance (ESR). Visible light photocatalytic performance of GR-TiO2 composites was evaluated for photocatalytic degradation of organic dye Rhodamine B. It was found that the amount of graphene oxide (GO) added obviously affects morphologies of TiO2 mesocrystals and photocatalytic activities of as-prepared nanocomposites. Composites prepared in the presence of different amounts of GO all exhibit higher photocatalytic activity than pure TiO2 mesocrystals and P25, the composite obtained by using 20mg GO presents the most uniform TiO2 mesocrystals in the composite and shows the highest photocatalytic efficiency. The mechanism for the generation of TiO2 mesocrystals in the GR-TiO2 composite is proposed and possible reasons for the enhancement in visible light photocatalytic efficiency are also discussed.
    Full-text Article · Jul 2013 · Journal of hazardous materials
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    Xiaofei Yang · Haiying Cui · Yang Li · [...] · Hua Tang
    [Show abstract] [Hide abstract] ABSTRACT: A facile and effective hydrothermal method for the fabrication of the Ag3PO4-graphene (Ag3PO4-GR) visible light photocatalyst has been developed to improve the photocatalytic performance and stability of Ag3PO4, and also to reduce the high cost of Ag3PO4 for practical uses. The size and morphology of Ag3PO4 particles could be tailored by the electrostatically driven assembly of Ag+ on graphene oxide (GO) sheets and by the controlled growth of Ag3PO4 particles on the GO surface. The generation of Ag3PO4 and the transformation of GO to GR can be achieved simultaneously in the hydrothermal process. The improved photocatalytic activity of Ag3PO4-GR composites under visible light irradiation is attributed to high-surface-area GR sheets, enhanced absorption of organic dyes, and more efficient separation of photogenerated electron–hole pairs. The transfer of photogenerated electrons from the surface of Ag3PO4 to GR sheets also reduces the possibility of decomposing Ag+ to metallic Ag, suggesting an improved stability of recyclable Ag3PO4-GR composite photocatalyst. Moreover, with the advances in the large-scale production of high-quality GO, the use of GO as the starting material can also reduce the cost for the synthesis of Ag3PO4-based photocatalysts without weakening their photocatalytic activities.
    Full-text Article · Feb 2013 · ACS Catalysis
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    [Show abstract] [Hide abstract] ABSTRACT: Graphene oxide (GO)-enwrapped Ag3PO4 composites were successfully fabricated by the electrostatically-driven assembly of positively charged silver ions on the negatively charged GO sheets, followed by the controlled growth of sphere-like Ag3PO4 particles on GO sheets via an in-situ ion-exchange method. Moreover, GO–Ag3PO4 composites were fully characterized and the visible light photocatalytic performance of the GO–Ag3PO4 sample was investigated. The results indicated that the presence of GO sheets could effectively tailor the size of Ag3PO4 particles, GO–Ag3PO4 composites exhibited excellent visible-light absorption, and the photocatalytic degradation efficiency of Rhodamine B (RhB) over GO–Ag3PO4 composites is apparently higher than with pure Ag3PO4 mainly due to the photo-induced holes and the generation of irradiated active superoxide radicals.
    Full-text Article · Feb 2013 · Materials Letters
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    Haiying Cui · Xiaofei Yang · Jieling Qin · [...] · Yang Li
    [Show abstract] [Hide abstract] ABSTRACT: In this study, an amino acid, glutamine, has been employed as the modifier in the hydrothermal synthesis of rod-like hydroxyapatite (HAp) nanoparticles. X-ray diffractometer results confirm the formation of a typical HAp phase without impurities and microscopic results indicate that the morphology and size of the as-prepared products could be controlled by adjusting the pH value of the hydrothermal system. Owing to a variety of amino acids and characteristics of as-synthesised nano-sized HAp, the findings may have implications in the large-scale controllable synthesis of well-defined HAp nanomaterials; it may also provide a general facile and low-cost method for the preparation of uniform nanostructured HAp by utilising biomolecules as modifiers.
    Full-text Article · Dec 2012 · Micro & Nano Letters
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    Rongxian Zhang · Haiying Cui · Xiaofei Yang · [...] · Yang Li
    [Show abstract] [Hide abstract] ABSTRACT: Rod-like nanosized silver tungstate (Ag2WO4) was synthesised via a facile hydrothermal method and characterised by field emission scanning electron microscopy, X-ray diffraction, Raman spectroscopy and electron spin resonance spectroscopy. Under ultraviolet (UV) light, nearly complete degradation of rhodamine B (RhB) was observed in Ag2WO4 suspension after irradiation for 60 min, around 15 RhB was absorbed in the dark. However, more than 60 of methyl blue was absorbed in the dark and the rest was observed to be completely degraded upon UV light irradiation for 10 min. The formed superoxide (O2-.) and hydroxyl (·OH) radicals, as well as photoinduced holes were considered to be the dominant active species in the photocatalytic process.
    Full-text Article · Dec 2012 · Micro & Nano Letters
  • Yan Jiang · Yang Li · Bing Liang · [...] · Ze Wang
    [Show abstract] [Hide abstract] ABSTRACT: The tribological behavior of graphene oxide (GO) films deposited on a mica substrate has been investigated by atomic force microscopy, in which different voltages were applied to a tip. It was found that the frictional forces on the GO films remain unchanged in the presence of negative tip voltages, while the frictional forces increase remarkably with an increase of the voltage when positive voltages are given to the tip, and at a certain positive tip voltage the frictional forces reach a stable value with increasing number of repeated cycles. To study the influence of the tip voltage on the frictional forces of the GO films, the adhesive and electrostatic force gradients between the tip and GO films were measured. The results showed that the adhesive and electrostatic forces increased with increase of the positive tip voltages. This phenomenon is due to the polarization of charges in the GO films induced by the applied tip voltages, which causes intensive electrostatic interactions between the tip and GO films and a corresponding rise in the adhesive forces and the frictional forces.
    Article · Nov 2012 · Nanotechnology