Nano-hydroxyapatite/poly（e-caprolactone） （nHA/PCL） composite materials are among the best candidates for application in bone tissue engineering. As the main technique to fabricate porous scaffolds, electrospilming...Nano-hydroxyapatite/poly（e-caprolactone） （nHA/PCL） composite materials are among the best candidates for application in bone tissue engineering. As the main technique to fabricate porous scaffolds, electrospilming produce scaffolds with unsatisfactory mechanical strength and limited pore size for cdi infiltration. Micron-sized fiber assembly with higher mechanical strength is qualified to structure hybrid scaffolds. In this study, nHA/PCL monofilament fibers with different mass ratios were fabricated through melt-spinning. Transmission electron microscope （TEM） was used to observe the aggregation between nHA parfides. Other characterizations including scanning electron microscopy （SEM）, attenuated total reflection Fourier transform infrared spectroscopy （ATR.FTIR） and X-ray diffraction （XRD） were done to discuss the morphology, components and crystallization of the nHA/PCL composite fibers, respectively. The influence of nHA/PCL mass ratio on the tensile properties and water contact angle of composite fibers was also studied. The SEM images show the homogeneous dispersion of nano partides in the polymer matrix. Besides, nHA content increases the tensile strength, initial modulus and hydrophillcity of the composite fibers under the premise of spinnability. This kind of fibers is strong enough to fabricate fiber assembly which may have potential application in bone tissue engineering.展开更多
RT-PCR was employed to amplify the cDNA of HA gene of influenza A/Chicken/Guangdong/SS/94(H 9N 2)with a pair of degenerate primers and the cDNA were cloned into the T-T windows of plasmid pMD18-T.The inserts were sequ...RT-PCR was employed to amplify the cDNA of HA gene of influenza A/Chicken/Guangdong/SS/94(H 9N 2)with a pair of degenerate primers and the cDNA were cloned into the T-T windows of plasmid pMD18-T.The inserts were sequenced,at first time,and the results revealed that the HA gene had a long complete open reading frame and composed of 1,683 nucleotides,coding for 560 amino acids.The amino acid sequences of the HA connecting peptide revealed that A/Chicken/Guangdong/SS/94(H 9N 2)had X-X-X-R(X,not basic amino acid)at the proteolytic cleavage site.The molecular basis of the HA gene was compatible with not highly pathogenicity.Comparison of the degree of homology of HA gene showed 82%-98% nucleotide sequence and amino acid sequence homology among the isolate and the other H 9N 2 subtype AIV in GenBank. Thus, the HA gene of influenza A/Chicken/Guangdong/SS/94 belonged to H 9 subtype.展开更多
基金Science and Technology Support Program of Shanghai,China(No.16441903803)National Postdoctoral Foundation,China(No.2016M590299)
文摘Nano-hydroxyapatite/poly（e-caprolactone） （nHA/PCL） composite materials are among the best candidates for application in bone tissue engineering. As the main technique to fabricate porous scaffolds, electrospilming produce scaffolds with unsatisfactory mechanical strength and limited pore size for cdi infiltration. Micron-sized fiber assembly with higher mechanical strength is qualified to structure hybrid scaffolds. In this study, nHA/PCL monofilament fibers with different mass ratios were fabricated through melt-spinning. Transmission electron microscope （TEM） was used to observe the aggregation between nHA parfides. Other characterizations including scanning electron microscopy （SEM）, attenuated total reflection Fourier transform infrared spectroscopy （ATR.FTIR） and X-ray diffraction （XRD） were done to discuss the morphology, components and crystallization of the nHA/PCL composite fibers, respectively. The influence of nHA/PCL mass ratio on the tensile properties and water contact angle of composite fibers was also studied. The SEM images show the homogeneous dispersion of nano partides in the polymer matrix. Besides, nHA content increases the tensile strength, initial modulus and hydrophillcity of the composite fibers under the premise of spinnability. This kind of fibers is strong enough to fabricate fiber assembly which may have potential application in bone tissue engineering.
文摘RT-PCR was employed to amplify the cDNA of HA gene of influenza A/Chicken/Guangdong/SS/94(H 9N 2)with a pair of degenerate primers and the cDNA were cloned into the T-T windows of plasmid pMD18-T.The inserts were sequenced,at first time,and the results revealed that the HA gene had a long complete open reading frame and composed of 1,683 nucleotides,coding for 560 amino acids.The amino acid sequences of the HA connecting peptide revealed that A/Chicken/Guangdong/SS/94(H 9N 2)had X-X-X-R(X,not basic amino acid)at the proteolytic cleavage site.The molecular basis of the HA gene was compatible with not highly pathogenicity.Comparison of the degree of homology of HA gene showed 82%-98% nucleotide sequence and amino acid sequence homology among the isolate and the other H 9N 2 subtype AIV in GenBank. Thus, the HA gene of influenza A/Chicken/Guangdong/SS/94 belonged to H 9 subtype.
