Fibrous components and structural morphology of the connective tissue of the lamina cribrosa obtained from 35 normal human autopsy eyes were examined by histochemical staining, transmission electron microscopic and co...Fibrous components and structural morphology of the connective tissue of the lamina cribrosa obtained from 35 normal human autopsy eyes were examined by histochemical staining, transmission electron microscopic and computer-展开更多
Cu_(90)Zr_(10-x)Al_x(x=1, 3, 5, 7, 9; at.%) alloy rods were synthesized based on rapid solidification method. The structure, distribution of elements, mechanical properties and electrical conductivity of the Cu-based ...Cu_(90)Zr_(10-x)Al_x(x=1, 3, 5, 7, 9; at.%) alloy rods were synthesized based on rapid solidification method. The structure, distribution of elements, mechanical properties and electrical conductivity of the Cu-based alloy samples were studied using X-ray diffraction(XRD), scanning electron microscope(SEM), electro-probe micro-analyzer(EPMA), uniaxial compression test and four-probe technique. The as-cast Cu_(90)Zr_(10-x)Al_x(x=1, 3, 5; at.%) alloy rods with a diameter of 2 mm exhibit good mechanical properties and electrical conductivity, i.e., high compressive yield strength of 812-1513 MPa, Young's modulus of 52-85 GPa, Vickers hardness of 250-420 and electrical conductivity of 11.1%-12.6% IACS(International Annealed Copper Standard). The composite microstructure composed of high density fibrous duplex structure(Cu_5Zr and α-Cu phases) is thought to be the origin of the high strength.展开更多
Silica biomaterials including Bioglass offer great biocompatibility and bioactivity but fail to provide pore and degradation features needed for tissue engineering.Herein we report on the synthesis and characterizatio...Silica biomaterials including Bioglass offer great biocompatibility and bioactivity but fail to provide pore and degradation features needed for tissue engineering.Herein we report on the synthesis and characterization of novel amorphous silica fiber matrices to overcome these limitations.Amorphous silica fibers were fused by sintering to produce porous matrices.The effects of sacrificial polymer additives such as polyvinyl alcohol(PVA)and cellulose fibers(CF)on the sintering process were also studied.The resulting matrices formed between sintering temperatures of 1,350-1,550◦C retained their fiber structures.The matrices presented pores in the range of 50-200μm while higher sintering temperatures resulted in increased pore diameter.PVA addition to silica significantly reduced the pore diameter and porosity compared with silica matrices with or without the addition of CF.The PVA additive morphologically appeared to fuse the silica fibers to a greater extent and resulted in significantly higher compressive modulus and strength than the rest of the matrices synthesized.These matrices lost roughly 30%of their original mass in an in vitro degradation study over 40 weeks.All matrices absorbed 500 wt%of water and did not change in their overall morphology,size,or shape with hydration.These fiber matrices supported human mesenchymal stem cell adhesion,proliferation,and mineralized matrix production.Amorphous silica fiber biomaterials/matrices reported here are biodegradable and porous and closely resemble the native extracellular matrix structure and water absorption capacity.Extending the methodology reported here to alter matrix properties may lead to a variety of tissue engineering,implant,and drug delivery applications.展开更多
文摘Fibrous components and structural morphology of the connective tissue of the lamina cribrosa obtained from 35 normal human autopsy eyes were examined by histochemical staining, transmission electron microscopic and computer-
基金supported by the National Natural Science Foundation of China(Nos.51301029 and 51375071)the Fundamental Research Funds for the Central Universities,China(No.DUT11RC(3)86)
文摘Cu_(90)Zr_(10-x)Al_x(x=1, 3, 5, 7, 9; at.%) alloy rods were synthesized based on rapid solidification method. The structure, distribution of elements, mechanical properties and electrical conductivity of the Cu-based alloy samples were studied using X-ray diffraction(XRD), scanning electron microscope(SEM), electro-probe micro-analyzer(EPMA), uniaxial compression test and four-probe technique. The as-cast Cu_(90)Zr_(10-x)Al_x(x=1, 3, 5; at.%) alloy rods with a diameter of 2 mm exhibit good mechanical properties and electrical conductivity, i.e., high compressive yield strength of 812-1513 MPa, Young's modulus of 52-85 GPa, Vickers hardness of 250-420 and electrical conductivity of 11.1%-12.6% IACS(International Annealed Copper Standard). The composite microstructure composed of high density fibrous duplex structure(Cu_5Zr and α-Cu phases) is thought to be the origin of the high strength.
基金support from the National Institute of Biomedical Imaging and Bioengineering(NIBIB)of the National Institutes of Health(#R01EB030060R01EB020640)Dr.Nukavarapu also acknowledges funding from NSF EFMA(#1908454).
文摘Silica biomaterials including Bioglass offer great biocompatibility and bioactivity but fail to provide pore and degradation features needed for tissue engineering.Herein we report on the synthesis and characterization of novel amorphous silica fiber matrices to overcome these limitations.Amorphous silica fibers were fused by sintering to produce porous matrices.The effects of sacrificial polymer additives such as polyvinyl alcohol(PVA)and cellulose fibers(CF)on the sintering process were also studied.The resulting matrices formed between sintering temperatures of 1,350-1,550◦C retained their fiber structures.The matrices presented pores in the range of 50-200μm while higher sintering temperatures resulted in increased pore diameter.PVA addition to silica significantly reduced the pore diameter and porosity compared with silica matrices with or without the addition of CF.The PVA additive morphologically appeared to fuse the silica fibers to a greater extent and resulted in significantly higher compressive modulus and strength than the rest of the matrices synthesized.These matrices lost roughly 30%of their original mass in an in vitro degradation study over 40 weeks.All matrices absorbed 500 wt%of water and did not change in their overall morphology,size,or shape with hydration.These fiber matrices supported human mesenchymal stem cell adhesion,proliferation,and mineralized matrix production.Amorphous silica fiber biomaterials/matrices reported here are biodegradable and porous and closely resemble the native extracellular matrix structure and water absorption capacity.Extending the methodology reported here to alter matrix properties may lead to a variety of tissue engineering,implant,and drug delivery applications.