Objective To acquire oval cells （progenitor stem cells ） from adult rat liver of different models including diabetic rats. Methods Thirty Sprague-Dawley （ SD ） rats were divided into 5 groups randomly： control, 2...Objective To acquire oval cells （progenitor stem cells ） from adult rat liver of different models including diabetic rats. Methods Thirty Sprague-Dawley （ SD ） rats were divided into 5 groups randomly： control, 2-acetylaminofluorene （ 2-AAF ）, 2-AAF ＋ partial hepatectomy （ PH ）, 2-AAF ＋ carbon tetrachloride （ CCl4 ）, and diabetic groups. As two-step collagenase perfusion protocol of Seglen, oval cells were isolated by Percoll density gradient centrifugation. Thy1. 1 positive cells were sorted by flow cytometry, and then cultured in Dulbecco＇s minimum Eagle＇s medium （DMEM）. Immunofluorescence staining was applied to labelling Thyl. 1. Results Different rates of Thy1.1 positive oval cells were found in different rat model groups ： 0. 5 % in 2-AAF, 0. 3% in 2-AAF ＋ PH, 0. 2% in 2-AAF ＋ CCl4, 0. 1% in diabetic, and 0. 0% in control. Isolated cells adhered to plate with fusiform or polygon as epithelial cells. Conclusion Progenitor stem cells exist in injured liver tissue including those from diabetic rats.展开更多
Different cell populations from bone marrow are used in various clinical trials for cardiac diseases during last decade. Four clinical studies are on going in our institution and enrol patients with cardiac diseases, ...Different cell populations from bone marrow are used in various clinical trials for cardiac diseases during last decade. Four clinical studies are on going in our institution and enrol patients with cardiac diseases, coronary disease and type 2 diabetes, patients with osteoarthritis. Density gradient is used to separate bone marrow mononuclear cells. Cell processing looses are significant. To find out critical control points we analysed processing process and differences in cell yields between operators performing cell extraction. Bone marrow mononuclear cells were isolated using Ficoll density gradient centrifugation. Cells were counted using flow cytometry for mononuclear cell total counts, CD34＋ population count and viability analysis. The patients who underwent bone marrow aspiration followed by cell isolation received cell suspension for transplantation. Two cells processing for separate patients were performed at once. Same standard operation procedures were applied. Processing looses between operators performing cell extraction were analysed. Bone marrow samples from eight patients were processed. Mononuclear cells were extracted. Operator performances were compared. Operator A average bone marrow mononuclear cell yield in starting material was 9,97 ± 9,98 %, CD34＋ population yield 75,46±79,67%. Operator B average bone marrow mononuclear cell yield in starting material was 24,68 ± 14,8 %, CD34＋ population yield 70,42 ±44.84%. Operator A average cell viability in starting material was 45,24 ± 9,55%, after cell processing 42,96 ± 23,66 %. Operator B average cell viability in starting material was 49,85 ± 5,48%, after cell processing 69,52 ± 6,65 %.展开更多
We present a systematic study of the effects of surfactants in the separation of single-walled carbon nanotubes （SWNTs） by density gradient ultracentrifugation （DGU）. Through analysis of the buoyant densities, lay...We present a systematic study of the effects of surfactants in the separation of single-walled carbon nanotubes （SWNTs） by density gradient ultracentrifugation （DGU）. Through analysis of the buoyant densities, layer positions, and optical absorbance spectra of SWNT separations using the bile salt sodium deoxycholate （DOC） and the anionic salt sodium dodecyl sulfate （SDS）, we clarify the roles and interactions of these two surfactants in yielding different DGU outcomes. The separation mechanism described here can also help in designing new DGU experiments by qualitatively predicting outcomes of different starting recipes, improving the efficacy of DGU and simplifying post-DGU fractionation.展开更多
High quality gold nanorods （NRs） with a monodisperse size and aspect ratio are essential for many applications. Here, we describe how nearly monodisperse gold NRs can be separated from polydisperse samples using den...High quality gold nanorods （NRs） with a monodisperse size and aspect ratio are essential for many applications. Here, we describe how nearly monodisperse gold NRs can be separated from polydisperse samples using density gradient ultracentrifugation. Size and dimension analysis by transmission electron microscopy （TEM） and absorption spectroscopy revealed that the Au NRs were separated mainly as a function of their aspect ratio The surface-enhanced Raman scattering （SERS） activity of Au NRs with lower aspect ratio is notably stronger than that of NRs with higher aspect ratio under 633 nm laser excitation, due to the size-dependent absorption of the longitudinal plasmon band. The separation approach provides a method to improve the quality of NRs produced by large scale synthetic methods.展开更多
CdS nanorods have been sorted by length using a density gradient ultracentrifuge rate separation method. The fractions containing longer rods showed relatively stronger oxygen-related surface trap emission, while the ...CdS nanorods have been sorted by length using a density gradient ultracentrifuge rate separation method. The fractions containing longer rods showed relatively stronger oxygen-related surface trap emission, while the shorter ones had dominant band-edge emission. These results suggest that the final length distribution of CdS nanorods is not a result of random nucleation and growth, but is related to the local synthesis conditions. Inspired by these findings, different synthesis environments （N2, air, and 02） have been employed in order to tailor the length distribution. In addition to the rod length, the photoluminescence properties of CdS nanorods can also be manipulated. Increasing the oxygen partial pressure significantly changed the growth behavior of CdS nanorods by improving the anisotropic growth.展开更多
基金Supported by Shanghai Municipal Education Commission Key Project (07ZZ35)
文摘Objective To acquire oval cells （progenitor stem cells ） from adult rat liver of different models including diabetic rats. Methods Thirty Sprague-Dawley （ SD ） rats were divided into 5 groups randomly： control, 2-acetylaminofluorene （ 2-AAF ）, 2-AAF ＋ partial hepatectomy （ PH ）, 2-AAF ＋ carbon tetrachloride （ CCl4 ）, and diabetic groups. As two-step collagenase perfusion protocol of Seglen, oval cells were isolated by Percoll density gradient centrifugation. Thy1. 1 positive cells were sorted by flow cytometry, and then cultured in Dulbecco＇s minimum Eagle＇s medium （DMEM）. Immunofluorescence staining was applied to labelling Thyl. 1. Results Different rates of Thy1.1 positive oval cells were found in different rat model groups ： 0. 5 % in 2-AAF, 0. 3% in 2-AAF ＋ PH, 0. 2% in 2-AAF ＋ CCl4, 0. 1% in diabetic, and 0. 0% in control. Isolated cells adhered to plate with fusiform or polygon as epithelial cells. Conclusion Progenitor stem cells exist in injured liver tissue including those from diabetic rats.
文摘Different cell populations from bone marrow are used in various clinical trials for cardiac diseases during last decade. Four clinical studies are on going in our institution and enrol patients with cardiac diseases, coronary disease and type 2 diabetes, patients with osteoarthritis. Density gradient is used to separate bone marrow mononuclear cells. Cell processing looses are significant. To find out critical control points we analysed processing process and differences in cell yields between operators performing cell extraction. Bone marrow mononuclear cells were isolated using Ficoll density gradient centrifugation. Cells were counted using flow cytometry for mononuclear cell total counts, CD34＋ population count and viability analysis. The patients who underwent bone marrow aspiration followed by cell isolation received cell suspension for transplantation. Two cells processing for separate patients were performed at once. Same standard operation procedures were applied. Processing looses between operators performing cell extraction were analysed. Bone marrow samples from eight patients were processed. Mononuclear cells were extracted. Operator performances were compared. Operator A average bone marrow mononuclear cell yield in starting material was 9,97 ± 9,98 %, CD34＋ population yield 75,46±79,67%. Operator B average bone marrow mononuclear cell yield in starting material was 24,68 ± 14,8 %, CD34＋ population yield 70,42 ±44.84%. Operator A average cell viability in starting material was 45,24 ± 9,55%, after cell processing 42,96 ± 23,66 %. Operator B average cell viability in starting material was 49,85 ± 5,48%, after cell processing 69,52 ± 6,65 %.
基金Acknowledgements Part of this work was financially supported by Grant- in-Aid for Scientific Research （No. 22226006 and 19054003）, ＂Development of Nanoelectronic Device Technology＂ of New Energy and Industrial Technology Development Organization （NEDO）, and the Global Centers of Excellence （COE） Program ＂Global Center for Excellence for Mechanical Systems Innovation＂. P. Z. acknowledges a scholarship granted by the China Scholarship Council and G. L. acknowledges support from the NanoJapan program funded by the National Science Foundation.
文摘We present a systematic study of the effects of surfactants in the separation of single-walled carbon nanotubes （SWNTs） by density gradient ultracentrifugation （DGU）. Through analysis of the buoyant densities, layer positions, and optical absorbance spectra of SWNT separations using the bile salt sodium deoxycholate （DOC） and the anionic salt sodium dodecyl sulfate （SDS）, we clarify the roles and interactions of these two surfactants in yielding different DGU outcomes. The separation mechanism described here can also help in designing new DGU experiments by qualitatively predicting outcomes of different starting recipes, improving the efficacy of DGU and simplifying post-DGU fractionation.
基金Acknowledgements This work was financially supported by the National Natural Science Foundation of China （NSFC）, Beijing Natural Science Foundation （No. 2102033）, the Programfor New Century Excellent Talents in Universities, and the 973 Program （No. 2009CB939801）.
文摘High quality gold nanorods （NRs） with a monodisperse size and aspect ratio are essential for many applications. Here, we describe how nearly monodisperse gold NRs can be separated from polydisperse samples using density gradient ultracentrifugation. Size and dimension analysis by transmission electron microscopy （TEM） and absorption spectroscopy revealed that the Au NRs were separated mainly as a function of their aspect ratio The surface-enhanced Raman scattering （SERS） activity of Au NRs with lower aspect ratio is notably stronger than that of NRs with higher aspect ratio under 633 nm laser excitation, due to the size-dependent absorption of the longitudinal plasmon band. The separation approach provides a method to improve the quality of NRs produced by large scale synthetic methods.
文摘CdS nanorods have been sorted by length using a density gradient ultracentrifuge rate separation method. The fractions containing longer rods showed relatively stronger oxygen-related surface trap emission, while the shorter ones had dominant band-edge emission. These results suggest that the final length distribution of CdS nanorods is not a result of random nucleation and growth, but is related to the local synthesis conditions. Inspired by these findings, different synthesis environments （N2, air, and 02） have been employed in order to tailor the length distribution. In addition to the rod length, the photoluminescence properties of CdS nanorods can also be manipulated. Increasing the oxygen partial pressure significantly changed the growth behavior of CdS nanorods by improving the anisotropic growth.
