The electrospinning of gelatin aqueous solution was successfully carried out by elevating the spinning temperature. The effects of spinning temperature and solution concentration were investigated on the morphology of gelatin nanofibers in the current study. To improve the stability and mechanical properties in moist state, the gelatin nanofibrous membrane was chemically crosslinked by 1-ethyl-3-dimethyl-aminopropyl carbodiimide hydrochloride and N-hydroxyl succinimide. The concentration of crosslinker was optimized by measuring the swelling degree and weight loss. Nanofibrous structure of the membrane was retained after lyophilization, although the fibers were curled and conglutinated. Tensile test revealed that the hydrated membrane becomes pliable and provides predetermined mechanical properties. Periodontal ligament cells cultured on the membrane in vitro exhibited good cell attachment, growth, and proliferation. Gelatin nanofibrous membrane can be one of promising biomaterials for the regeneration of damaged periodontal tissues.

Significant effort has been devoted to fabricating various biomaterials to satisfy specific clinical requirements. In this study, we developed a new type of guided tissue regeneration (GTR) membrane by electrospinning a suspension consisting of poly( l-lactic acid), multiwalled carbon nanotubes, and hydroxyapatite (PLLA/MWNTs/HA). MWNTs/HA nanoparticles were uniformly dispersed in the membranes, and the degradation characteristics were far improved. Cytologic research revealed that the PLLA/MWNTs/HA membrane enhanced the adhesion and proliferation of periodontal ligament cells (PDLCs) by 30% and inhibited the adhesion and proliferation of gingival epithelial cells by 30% also, compared with the control group. After PDLCs were seeded into the PLLA/MWNTs/HA membrane, cell/membrane composites were implanted into the leg muscle pouches of immunodeficient mice. Histologic examinations showed that PDLCs attached on the membranes functioned well in vivo. This new type of membrane shows excellent dual biological functions and satisfied the requirement of the GTR technique successfully in spite of a monolayer structure. Compared with other GTR membranes on sale or in research, the membrane can simplify the manufacturing process, reduce the fabrication cost, and avoid possible mistakes in clinical application. Moreover, it does not need to be taken out after surgery. PLLA/MWNTs/HA membranes have shown great potential for GTR and tissue engineering.

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Elastoplastic and time-dependent analysis of seismic structures has become a major analysis technique in popularly accepted performance-based seismic design. However, the primary diffi culty in using this technique is the lack of a unifi ed criterion in the selection of various intensity indices of ground motions. Various earthquake factors infl uencing the elastoplastic response of seismic structures are highly sophisticated. Hence, it is vitally important to choose an appropriate and comprehensive earthquake intensity index to achieve an accurate correlation with the structural performance. In this study, a total of 30 earthquake intensity indices published in the literature are reviewed and are evaluated through correlation analysis based on 60 ground motion records. Examined herein is the correlation between existing earthquake intensity indices and the seismic responses of elastoplastic single degree-of-freedom and multi degree-of-freedom systems. The characteristics and applicability of such indices are also discussed in some detail, based on which appropriate earthquake intensity indices are recommended. areas are structural engineering, performance-based seismic design of structures, fi bre composite structures and seismic retrofi tting of unreinforced/historical structures using fi bre reinforced polymer (FRP). QianliMa now works at COFCO Property (Group) Company Limited, China. He obtained his PhD in 2009 and his BEng degree in 2004 from Tsinghua University, China. His main research areas are structural engineering and performance-based seismic design of structures. Zhiwei Miao is Lecture in the School of Civil Engineering, Southeast University, China. He obtained his PhD in 2009 and his BEng degree in 2004 from Tsinghua University, China. His main research areas are structural engineering, fi nite element modelling of concrete structures and performancebased seismic design of structures. Hong Guan is Associate Professor in the Griffi th School of Engineering, Griffi th University Gold Coast Campus. She obtained her PhD in 1997 from the same University, her MEng degree in 1992 from the Asian Institute of Technology, Bangkok and her double BEng degrees in 1988 from Tsinghua University, China. Her main research areas are structural engineering and computational mechanics with special interests in fi nite element modelling and failure analysis of concrete structures, structural topology optimisation, application of fi nite element method in dental implant research and bridge deterioration model. Yan Zhuge has a BEng (Hons) in Civil Engineering and a Masters in Structural Engineering from