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Hu X.,Guangzhou University | Yu W.,Shanghai Center for Biomedical Engineering | Yao J.,Guangzhou University
Journal of Computational Information Systems | Year: 2010

Two-dimensional principal component analysis (2DPCA) is essentially principal component analysis (PCA) if only row is viewed as a computational unit, thus it can only reveal the variations between rows of one face image. In order to extract more class information from one training face image, this paper proposed a new method called multi-oriented two-dimensional principal component analysis. In the proposed method, one face image was firstly rotated θ degrees using bilinear interpolation to gain several face images with different directions. Then the class features were extracted from origin face image and its rotated face images for each face image. The method's performance was tested in FERET database with one training image per person. Results showed the method is more effective and achieves higher recognition rate than other methods. Copyright © 2010 Binary Information Press May, 2010. Source

Lin M.,Fujian Medical University | Xu P.,Fudan University | Zhong W.,Shanghai Center for Biomedical Engineering
Journal of Biomedical Materials Research - Part B Applied Biomaterials | Year: 2012

Poly(2-hydroxyethyl acrylate) (PHEA) is a polymer hydrogel that can be used as a biomaterial. In this study, PHEA/silica composites containing aspirin as a model drug were prepared, and their drug release behaviors were tested. 2-Hydroxyethyl acrylate (HEA) was first copolymerized with 3-(trimethoxysilyl) propyl methacrylate (MSMA) in the presence of ammonium persulphate and then condensed with silicic acid oligomer. The composites were characterized with Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). In addition, water uptake and matrix erosion of PHEA/silica of different weight ratios were also investigated. The results indicated that the silica particles were well dispersed in PHEA hydrogels. The in vitro drug release test revealed that the release rate of aspirin decreased with the increasing content of silica. The drug release behaviors were analyzed by employing the power law, which showed that the release profiles were governed either by Case II diffusion or by anomalous diffusion. The 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyl tetrazolium bromide (MTT) assay of rabbit chondrocytes revealed that adding silica can improve the biocompatibility of PHEA to some extent. © 2012 WILEY PERIODICALS, INC. Source

Li H.,Huashan Hospital | Chen C.,Fudan University | Zhang S.,Huashan Hospital | Jiang J.,Huashan Hospital | And 5 more authors.
Acta Biomaterialia | Year: 2012

In this study layer by layer (LBL) self-Assembled coatings of hyaluronic acid (HA) and cationized gelatin (CG) were used to modify polyethylene terephthalate (PET) artificial ligament grafts. Changes in the surface properties were characterized by scanning electron microscopy, attenuated total reflection Fourier transform infrared spectroscopy, energy-dispersive X-ray spectroscopy, and contact angle and biomechanical measurements. The cell compatibility of this HA-CG coating was investigated in vitro on PET films seeded with human foreskin dermal fibroblasts over 7 days. The results of our in vitro studies demonstrated that the HA-CG coating significantly enhanced cell adhesion, facilitated cell growth, and suppressed the expression of inflammation-related genes relative to a pure PET graft. Furthermore, rabbit and porcine anterior cruciate ligament reconstruction models were used to evaluate the effect of this LBL coating in vivo. The animal experiment results proved that this LBL coating significantly inhibited inflammatory cell infiltration and promoted new ligament tissue regeneration among the graft fibers. In addition, the formation of type I collagen in the HA-CG coating group was much higher than in the control group. Based on these results we conclude that PET grafts coated with HA-CG have considerable potential as substitutes for ligament reconstruction. © 2012 Acta Materialia Inc. Source

Shen L.,Fudan University | Wu Y.,Fudan University | Zhang F.,Fudan University | Wu L.,OrbusNeich Medical Shenzhen Co. | And 8 more authors.
Clinical Research in Cardiology | Year: 2012

Background Delayed endothelialization contributes to stent thrombosis of current drug-eluting stents. The asymmetrical coating technique provides an anti-proliferative effect abluminally without affecting luminal endothelialization. Layer-by-layer self-assembled chitosan/heparin (C/H LBL) has been proved to promote re-endothelialization. A novel stent system, C/H LBL coated luminally and sirolimus released abluminally (C/H LBL-SES), was fabricated. Methods Bare metal stents (BMS), traditionally circumferential sirolimus-eluting stents (SES), and C/H LBL-SES were implanted into porcine coronary arteries. At the 7, 14 and 28 days follow-up (FU), angiography, intravascular ultrasound (IVUS), vasomotor function induced by acetylcholine (Ach), scanning-electron microscopy and histopathology were performed. Remodeling index (RI) was based on IVUS and defined as cross-sectional area (CSA) of vessel at in-stent segment divided by CSA of reference vessel and expressed as a percentage with a normal range from 0.95 to 1.05. Results Thirty-eight mini pigs were enrolled and 74 stents (BMS = 23, C/H LBL = 28, SES = 23) were implanted in this study. At 28 days after implantation, the diameter stenosis of C/H LBL-SES by quantitative coronary angiography was 18.8 ± 2.5 %, the area stenosis by histomorphometry was 24.2 ± 2.9 %, which were comparable to that of SES and superior to BMS. At 14 days, reendothelialization of C/H LBL-SES was almost completed, while only about 50 % of surface of SES was covered by endothelium. At 7, 14 and 28 days FU, although C/H LBLSES suffered a greater vasoconstriction induced by Ach infusion than BMS (P<0.05), it behaved better than SES (P<0.01). No sign of stent malapposition was detected, while RI was within the normal range by IVUS. No acute or subacute thrombotic events occurred in all three groups. Conclusions The asymmetrically designed C/H LBL-SES successfully inhibited neointima hyperplasia, while diminishing vasoconstriction after Ach-stress. Endothelialization of C/H LBL-SES was less affected compared with traditionally circumferentially coated SES. © Springer-Verlag 2012. Source

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