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Huang M.,Chongqing University | Huang M.,Chongqing Technology and Business University | Wang Y.,Key Laboratory of Biorheological Science and Technology | Luo Y.,Chongqing Technology and Business University | Pan F.,Chongqing University
Asian Journal of Chemistry

A novel shape memory porous scaffold was prepared by copolymerization and emulsion copolymerization method. Initially, isocyanate I terminated prepolymer was prepared from reaction of HO-terminated poly (lactide-co-p-dioxanone) with hexamethylene diisocyanate for 3 h at 70∼75 °C. Then the excess NCO reacted with butanediamine below 5 °C, aiming to realize chain extension. During this process, the porogen NaCl/PVP was introduced. The emulsion was dried by vacuum and the dried materials were compressed to special shape and then salt leaching method was used to prepare porous scaffold. The pore structure and pore size were characterized by scanning electron microscopy and the porosity was measured with liquid substitution method and connectivity was measured by calculating the ratio of drip mass to time. Mechanical performance and shape memory property were also studied. These results denoted that pore size and porosity have significant influence on the mechanical and shape memory properties of shape memory poly(urethane-urea). However, the shape memory property is as high as 52 % ∼ 80 % and mechanical modulus is 100-350 MPa, similar to the natural bone, which is beneficial to treatment of the non-union. Source

Yang D.D.,Chongqing University | Hou W.S.,Key Laboratory of Biorheological Science and Technology | Wu X.Y.,Chongqing University | Zheng X.L.,Chongqing University | And 2 more authors.
Proceedings of the Annual International Conference of the IEEE Engineering in Medicine and Biology Society, EMBS

Multitendoned extrinsic muscles of the human hand can be divided into several neuromuscular compartments (NMCs), each of which contributes to the ability of human finger to produce independent finger movements or force. The aim of this study was to investigate the changes in the spatial activation of flexor digitorum superficialis (FDS) during the fingertip force production with non-invasive multichannel surface electromyography (sEMG) technique. 7 healthy Subjects were instructed to match the target force level for 5s using individual index finger (I), individual middle finger (M) and the combination of the index and middle finger (IM) respectively. Simultaneously, a 2×6 electrode array was employed to record multichannel sEMG from FDS as finger force was produced. The entropy and center of gravity of the sEMG root mean square (RMS) map were computed to assess the spatial inhomogeneity in muscle activation and the change in spatial distribution of EMG amplitude related to the force generation of specific task finger. The results showed that the area and intensity of high amplitude region increased with force production, and the entropy increased with force level under the same task finger. The findings indicate that the change of spatial distribution of multitendoned extrinsic hand muscle activation is correlated to specific biomechanical functions. © 2011 IEEE. Source

Shi L.T.,Xian Jiaotong University | Fang L.,Xian Jiaotong University | Wu F.,Xian Jiaotong University | Liao X.L.,Key Laboratory of Biorheological Science and Technology | Meng F.M.,Xian Jiaotong University
Materials and Corrosion

Ternary Ni-Co-P/TiN (20nm) nanocomposite coatings with Co content in the range of 0-23wt% were successfully co-deposited on Al alloys by electroless plating. The morphology, composition, microstructure, micro-hardness, wear behavior, and corrosion properties of the coatings were tested using SEM, EDS, XRD, Vickers hardness, ball-on-disc wear tester, and electrochemical workstation, respectively. The effect of Co content on the tribological and corrosion properties of Ni-Co-P/TiN coatings was studied. It is found that all the coatings have a compact and rough granular structure with sub-micro globules non-uniformly distributed on the surface. The grain size and the content of Ni and P decrease, but the micro-hardness, adhesion force, friction coefficient, and corrosion resistance correspondingly enhance with the increase of Co content in Ni-Co-P/TiN coatings. The improved corrosion resistance of Ni-Co-P/TiN coating is due to the passivation behavior and small grain caused by the introduction of Co. Based on the excellent properties on the wear and corrosion resistance, ternary Ni-Co23-P/TiN coating with high Co content, may be applied as an optimum protective coating for Al alloys. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. Source

Zou H.,Key Laboratory of Biorheological Science and Technology | Huang J.,Key Laboratory of Biorheological Science and Technology | Fang F.,Chongqing University | Guo J.,Chongqing University
Advanced Materials Research

In this research the genes (amoA and hao) for ammonia monooxygenase (AMO) and hydroxylamine oxidoreductase (HAO) responsible for ammonia oxidation reaction in completely autotrophic nitrogen removal over nitrite process were cloned and sequenced, and the recombinant protein of AMO and HAO was expressed and characterized. The optimum temperature for AMO activity was 55 °C and more than 40% of the maximum activity was retained from 15-50 °C. The optimum pH for the enzyme was found to be pH 11.0. The highest activity for HAO was observed at 45 °C. More than 50% of the maximum activity was retained even at 55 °C. The dependence of HAO on pH was strong and only average 15% of residual activity left at pH ranging from 3.0-9.0. Study on the molecular and biochemistry properties of recombinant AMO and HAO will benefit for the manipulation of ammonia-oxidizing bacteria to achieve the goal of high efficiency of nitrogen removal. © (2011) Trans Tech Publications. Source

Yang W.,Key Laboratory of Biorheological Science and Technology | Yang W.,Chongqing University | Fang J.,Key Laboratory of Biorheological Science and Technology | Fang J.,Chongqing University | And 5 more authors.
Molecular Physics

In this study, the theoretical structures of armchair (6, 6) and zigzag (12, 0) TiOO2 nanotubes (TiNTs) were constructed by rolling the (101) layer of an anatase TiO2 crystal. The (101) layer was made using Materials Studio (MS) by cutting the cleave plane (101) of the anatase TiO2 crystal. Based on these structures, the basic properties of TiO2 nanotubes were investigated using MS. Molecular dynamics simulations were performed using the software NAMD to investigate the status and permeation of water through the TiO2 nanotubes. Structure analysis shows that both the inner and outer walls of the structures were terminated with oxygen atoms. The thicknesses of single tube walls are smaller than that of a perfect triple layer (2.20 Å) in bulk anatase TiO2. With regard to the bulk Ti-O bond length, the Ti-O bonds in the outer layer are elongated, and are shortened in the inner layer. Molecular dynamics simulation shows that the water molecules in the nanotubes move back and forth, as in one-dimensional Brownian motion. Moreover, the penetration properties of TiNTs are associated with their radii, with the TiNT with larger radii having better penetration properties. Thus, when used in drug delivery or filtration systems, armchair TiNT has a better effect than zigzag TiNT. © 2011 Taylor & Francis. Source

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