Significant progress has recently been made in enhancing the power conversion efficiency(PCE)of perovskite solar cells(PSCs).The electron transport layer(ETL),as an essential component of PSCs,significantly influences...Significant progress has recently been made in enhancing the power conversion efficiency(PCE)of perovskite solar cells(PSCs).The electron transport layer(ETL),as an essential component of PSCs,significantly influences the performance of devices.Traditional spin-coating method for preparing the ETL fails to fully cover the cusp of FTO transparent conductive glass substrate,leading to direct contact between perovskite film and FTO substrate,which induces charge recombination and reduces the performance of PSCs.To address this issue,an in-situ growth method was proposed to prepare conformal SnO_(2) films on FTO glass substrates in this study.The resulting SnO_(2) films are not only dense and uniform,fully covering the cusp of the FTO glass substrates and reducing the contact area between the FTO substrates and the perovskite films,but also facilitating the formation of perovskite films with large grain sizes.Moreover,the conformal SnO_(2) films can improve the charge extraction at the SnO_(2)/perovskite interface,reduce the trap density and trap-assisted recombination in PSCs,and thus enhance the PCE of PSCs.Through comparative experiments,it is found that the PSCs with in-situ grown SnO_(2) films show an improved PCE of 21.97%,which significantly increased compared to that with spin-coated SnO_(2) films(20.93%).All above data demonstrate that the as-prepared SnO_(2) film can serve as an ideal ETL.It is worth mentioning that this method avoids the use of corrosive hydrochloric acid and toxic thioglycolic acid,and it can also be extended to ITO flexible transparent conductive substrates in the future.展开更多
The nucleation and growth of eutectic cell in hypoeutectic Al-Si alloy was investigated using optical microscopy and scanning electron microscopy equipped with electron backscattering diffraction(EBSD).By revealing ...The nucleation and growth of eutectic cell in hypoeutectic Al-Si alloy was investigated using optical microscopy and scanning electron microscopy equipped with electron backscattering diffraction(EBSD).By revealing the eutectic cells and analyzing the crystallographic orientation,it was found that both the eutectic Si and Al phases in an eutectic cell were not single crystal,representing an eutectic cell consisting of small 'grains'.It is also suggested that the eutectic nucleation mode can not be determined based on the crystallographic orientation between eutectic Al phases and the neighboring primary dendrite Al phases.However,the evolution of primary dendrite Al phases affects remarkably the following nucleation and growth of eutectic cell.The coarse flake-fine fibrous transition of eutectic Si morphology involved in impurity elements modification may be independent of eutectic nucleation.展开更多
Objective To explore the feasibility and efficacy of lentivirus-mediated co-transfection of rat bone marrow mesenchymal stem cells (MSCs) with human vascular endothelial growth factor 165 (hVEGFI65) gene and human...Objective To explore the feasibility and efficacy of lentivirus-mediated co-transfection of rat bone marrow mesenchymal stem cells (MSCs) with human vascular endothelial growth factor 165 (hVEGFI65) gene and human bone morphogenetic protein 2 (hBMP2) gene. Methods The hVEGF165 and hBMP2 cDNAs were obtained from human osteosarcoma cell line MG63 and cloned into lentiviral expression vectors designed to co-express the copepod green fluorescent protein (copGFP). The expression lentivector and packaging Plasmid Mix were co-transferred to 293TN cells, which produced the lentivirus carrying hVEGF165 (Lv-VEGF) or hBMP2 ( Lv-BMP) , respectively. MSCs of Wistar rats were co-transfected with Lv-BMP and Lv-VEGF (BMP + VEGF group), or each alone (BMP group and VEGF group), or with no virus ( Control group). The mRNA and protein expressions of hVEGF165 and hBMP2 genes in each group were detected by real-time PCR and enzyme linked immunosorbent assay (ELISA). Results Lentiviral expression vectors carrying hVEGF165 or hBMP2 were correctly constructed and confirmed by restriction endonucleses analysis and DNA sequencing analysis. A transfer efficiency up to 90% was archieved in all the transfected groups detected by the fraction of fluorescent cells using fluorescent microscopy. From the results generated by real-time PCR and ELISA, VEGF165 and BMP2 genes were co-expressed in BMP + VEGF group. No significant difference of BMP2 expression was detected between BMP + VEGF and BMP groups ( P 〉 0. 05). Similarly, there was no significant difference of VEGF165 expression between BMP + VEGF and VEGF groups ( P 〉 0. 05). Conclusion VEGF165 and BMP2 genes were successfully co-expressed in MSCs by lentivirus-mediated co-transfection, which provided a further foundation for the combined gene therapy of bone regeneration.展开更多
The purpose of this paper is to investigate the political ideals of Sakae Osugi. Osugi argued that it was possible to establish a "society of mutual aid" based on the principle of "expansion of life". In his view,...The purpose of this paper is to investigate the political ideals of Sakae Osugi. Osugi argued that it was possible to establish a "society of mutual aid" based on the principle of "expansion of life". In his view, the hierarchy meant fixing the boundary and every boundary was an expression and exercise of power. That explains why anarchism is a perpetual movement which attempts to transcend every boundary forming the hierarchy. Osugi aimed at a free and diversified federal society where life is expanded. Osugi's influence stemmed from his articulation of the basic concerns of his generation. That generation confronted difficulties of a different order from those faced by the Meiji leadership. Osugi was attracted to the problem presented by the emerging masses: How could they be incorporated into society? His reply to this question was "mutual aid". This paper focuses on the relation between both notions of freedom and society and analyzes it throwing a light on the principle of "expansion of life" in Osugi's anarchism. Similarly to his contemporaries, it might be helpful to enquire into that principle, in a way that is beneficial to the relation between freedom and society.展开更多
The effects of pouring temperature,vibration frequency,and the number of curves in a serpentine channel,on themicrostructure and mechanical properties of Al-30%Si alloy processed by rheo-diecasting(RDC)were investigat...The effects of pouring temperature,vibration frequency,and the number of curves in a serpentine channel,on themicrostructure and mechanical properties of Al-30%Si alloy processed by rheo-diecasting(RDC)were investigated.The semisolidAl-30%Si alloy slurry was prepared by vibration serpentine channel pouring(VSCP)process in the RDC process.The results showthat the pouring temperature,the vibration frequency,and the number of the curves strongly affect the microstructure and mechanicalproperties of Al-30%Si alloy.Under experimental conditions of a pouring temperature of850°C,a twelve-curve copper channel anda vibration frequency of80Hz,the primary Si grains are refined into fine compact grains with average grain size of about24.6μm inthe RDC samples assisted with VSCP.Moreover,the ultimate tensile strength(UTS),elongation and hardness of the RDC sample are296MPa,0.87%and HB155,respectively.It is concluded that the VSCP process can effectively refine the primary Si grains.Therefinement of primary Si grains is the major cause for the improvement of the mechanical properties of the RDC sample.展开更多
The staphylococcal nuclease, encoded by the nucl gene, is an important virulence factor of Staphylococcus aureus. However, the physiological role of the nuclease has not been fully characterized. The current study obs...The staphylococcal nuclease, encoded by the nucl gene, is an important virulence factor of Staphylococcus aureus. However, the physiological role of the nuclease has not been fully characterized. The current study observed that biofilm development could be prevented in staphylococcal nuclease-producing strains of S. aureus; however, when the nucl gene was knocked out, the ability to form a biofilm significantly increased. Scanning electron and confocal scanning laser microscopy were used to evaluate the role of the nucl gene in biofilm formation. Moreover, the nucl gene product, staphylococcal nuclease, and re- combinant NUC1 protein were found to have a visible effect on other biofilm-forming bacteria, such as Pseudomonas aeru- ginosa, Actinobacillus pleuropneurnoniae, and Haernophilus parasuis. The current study showed a direct relationship between staphylococcal nuclease production and the prevention of biofilm development. The findings from this study underscore the important role of staphylococcal nuclease activity to prevent biofilm formation in S. aureus. They also provided evidence for the biological role of staphylococcal nucleases in other organisms.展开更多
基金Space Application System of China Manned Space Program。
文摘Significant progress has recently been made in enhancing the power conversion efficiency(PCE)of perovskite solar cells(PSCs).The electron transport layer(ETL),as an essential component of PSCs,significantly influences the performance of devices.Traditional spin-coating method for preparing the ETL fails to fully cover the cusp of FTO transparent conductive glass substrate,leading to direct contact between perovskite film and FTO substrate,which induces charge recombination and reduces the performance of PSCs.To address this issue,an in-situ growth method was proposed to prepare conformal SnO_(2) films on FTO glass substrates in this study.The resulting SnO_(2) films are not only dense and uniform,fully covering the cusp of the FTO glass substrates and reducing the contact area between the FTO substrates and the perovskite films,but also facilitating the formation of perovskite films with large grain sizes.Moreover,the conformal SnO_(2) films can improve the charge extraction at the SnO_(2)/perovskite interface,reduce the trap density and trap-assisted recombination in PSCs,and thus enhance the PCE of PSCs.Through comparative experiments,it is found that the PSCs with in-situ grown SnO_(2) films show an improved PCE of 21.97%,which significantly increased compared to that with spin-coated SnO_(2) films(20.93%).All above data demonstrate that the as-prepared SnO_(2) film can serve as an ideal ETL.It is worth mentioning that this method avoids the use of corrosive hydrochloric acid and toxic thioglycolic acid,and it can also be extended to ITO flexible transparent conductive substrates in the future.
基金Project(XKY2009035) supported by the Key Laboratory for Ecological-Environment Materials of Jiangsu Province,ChinaProject(11KJD430006) supported by the Natural Science Fund for Colleges and Universities in Jiangsu Province,ChinaProject(AE201034) supported by the Research Finds of Key Laboratory for Advanced Technology in Environmental Protection of Jiangsu Province,China
文摘The nucleation and growth of eutectic cell in hypoeutectic Al-Si alloy was investigated using optical microscopy and scanning electron microscopy equipped with electron backscattering diffraction(EBSD).By revealing the eutectic cells and analyzing the crystallographic orientation,it was found that both the eutectic Si and Al phases in an eutectic cell were not single crystal,representing an eutectic cell consisting of small 'grains'.It is also suggested that the eutectic nucleation mode can not be determined based on the crystallographic orientation between eutectic Al phases and the neighboring primary dendrite Al phases.However,the evolution of primary dendrite Al phases affects remarkably the following nucleation and growth of eutectic cell.The coarse flake-fine fibrous transition of eutectic Si morphology involved in impurity elements modification may be independent of eutectic nucleation.
基金Supported by Key Program of Shanghai Science and Technology Committee (054119520)
文摘Objective To explore the feasibility and efficacy of lentivirus-mediated co-transfection of rat bone marrow mesenchymal stem cells (MSCs) with human vascular endothelial growth factor 165 (hVEGFI65) gene and human bone morphogenetic protein 2 (hBMP2) gene. Methods The hVEGF165 and hBMP2 cDNAs were obtained from human osteosarcoma cell line MG63 and cloned into lentiviral expression vectors designed to co-express the copepod green fluorescent protein (copGFP). The expression lentivector and packaging Plasmid Mix were co-transferred to 293TN cells, which produced the lentivirus carrying hVEGF165 (Lv-VEGF) or hBMP2 ( Lv-BMP) , respectively. MSCs of Wistar rats were co-transfected with Lv-BMP and Lv-VEGF (BMP + VEGF group), or each alone (BMP group and VEGF group), or with no virus ( Control group). The mRNA and protein expressions of hVEGF165 and hBMP2 genes in each group were detected by real-time PCR and enzyme linked immunosorbent assay (ELISA). Results Lentiviral expression vectors carrying hVEGF165 or hBMP2 were correctly constructed and confirmed by restriction endonucleses analysis and DNA sequencing analysis. A transfer efficiency up to 90% was archieved in all the transfected groups detected by the fraction of fluorescent cells using fluorescent microscopy. From the results generated by real-time PCR and ELISA, VEGF165 and BMP2 genes were co-expressed in BMP + VEGF group. No significant difference of BMP2 expression was detected between BMP + VEGF and BMP groups ( P 〉 0. 05). Similarly, there was no significant difference of VEGF165 expression between BMP + VEGF and VEGF groups ( P 〉 0. 05). Conclusion VEGF165 and BMP2 genes were successfully co-expressed in MSCs by lentivirus-mediated co-transfection, which provided a further foundation for the combined gene therapy of bone regeneration.
文摘The purpose of this paper is to investigate the political ideals of Sakae Osugi. Osugi argued that it was possible to establish a "society of mutual aid" based on the principle of "expansion of life". In his view, the hierarchy meant fixing the boundary and every boundary was an expression and exercise of power. That explains why anarchism is a perpetual movement which attempts to transcend every boundary forming the hierarchy. Osugi aimed at a free and diversified federal society where life is expanded. Osugi's influence stemmed from his articulation of the basic concerns of his generation. That generation confronted difficulties of a different order from those faced by the Meiji leadership. Osugi was attracted to the problem presented by the emerging masses: How could they be incorporated into society? His reply to this question was "mutual aid". This paper focuses on the relation between both notions of freedom and society and analyzes it throwing a light on the principle of "expansion of life" in Osugi's anarchism. Similarly to his contemporaries, it might be helpful to enquire into that principle, in a way that is beneficial to the relation between freedom and society.
基金Project(5077400) supported by the National Natural Science Foundation of China
文摘The effects of pouring temperature,vibration frequency,and the number of curves in a serpentine channel,on themicrostructure and mechanical properties of Al-30%Si alloy processed by rheo-diecasting(RDC)were investigated.The semisolidAl-30%Si alloy slurry was prepared by vibration serpentine channel pouring(VSCP)process in the RDC process.The results showthat the pouring temperature,the vibration frequency,and the number of the curves strongly affect the microstructure and mechanicalproperties of Al-30%Si alloy.Under experimental conditions of a pouring temperature of850°C,a twelve-curve copper channel anda vibration frequency of80Hz,the primary Si grains are refined into fine compact grains with average grain size of about24.6μm inthe RDC samples assisted with VSCP.Moreover,the ultimate tensile strength(UTS),elongation and hardness of the RDC sample are296MPa,0.87%and HB155,respectively.It is concluded that the VSCP process can effectively refine the primary Si grains.Therefinement of primary Si grains is the major cause for the improvement of the mechanical properties of the RDC sample.
基金supported by the National Natural Science Foundation of China (Grant Nos. 31071515 and 31070113)the Special Foundation for Young Scientists of Sichuan Province,China (Grant No. 2011JQ0043)the Fundamental Research Funds for the Central Universities,Southwest University for Nationalities (Grant No. 09NZYZJ04)
文摘The staphylococcal nuclease, encoded by the nucl gene, is an important virulence factor of Staphylococcus aureus. However, the physiological role of the nuclease has not been fully characterized. The current study observed that biofilm development could be prevented in staphylococcal nuclease-producing strains of S. aureus; however, when the nucl gene was knocked out, the ability to form a biofilm significantly increased. Scanning electron and confocal scanning laser microscopy were used to evaluate the role of the nucl gene in biofilm formation. Moreover, the nucl gene product, staphylococcal nuclease, and re- combinant NUC1 protein were found to have a visible effect on other biofilm-forming bacteria, such as Pseudomonas aeru- ginosa, Actinobacillus pleuropneurnoniae, and Haernophilus parasuis. The current study showed a direct relationship between staphylococcal nuclease production and the prevention of biofilm development. The findings from this study underscore the important role of staphylococcal nuclease activity to prevent biofilm formation in S. aureus. They also provided evidence for the biological role of staphylococcal nucleases in other organisms.