Carbon quantum dots(CQDs)are emerging as the new-generation light absorber for solar energy conversion.However,the low photosensitization efficiency of CQDs is one of the current bottlenecks impeding their large-scale...Carbon quantum dots(CQDs)are emerging as the new-generation light absorber for solar energy conversion.However,the low photosensitization efficiency of CQDs is one of the current bottlenecks impeding their large-scale practical applications in photocatalysis.Therefore,developing a facile approach for the engineering and functionalization of CQDs-based composites to improve the photosensitization efficiency of CQDs is highly desirable.On account of the abundant functional groups,especially oxygen-containing functional groups such as carbonyl,carboxyl,and hydroxyl present on their surface,CQDs can be readily combined with various organic molecules or polymers as a surface passivation component to reduce the nonradioactive surface recombination of photo-generated charge carriers,thus enabling the CQDs to exhibit strong photoluminescence in the visible and near-infrared spectral regions.Consequently,polymer passivation has been demonstrated as an ideal strategy to make it accessible for improving the sensitization efficiency of CQDs in photocatalytic applications.Branched polyethylenimine(BPEI)is one of polymers that contains a high density of amine groups and exhibits high electron mobility,which can be used as an electron injection material at the interface of nanomaterials.Besides,the BPEI polymer with amino groups exhibiting positive charge has been utilized for designing heterogeneous catalysts by an electrostatic self-assembly strategy.Therefore,BPEI is expected to modify the surface of inorganic oxides semiconductor to enhance the photosensitization efficiency of CQDs under visible light.However,to date,the study in this regard has been still unavailable In this work,we developed a facile approach to engineer well-distributed CQDs via electrostatic interaction on BPEI passivated TiO2 composites(BTC)as photocatalysts.The BTC composites with an optimal loading of 5%(w,mass fraction)CQDs outperformed the TiO2/CQDs(TC)composite and referential BPEI/SiO2/CQDs(BSC)composites for the photoreduction of 4-nitroaniline under visible light irradiation.The structure of the fabricated BTC composites was systematically investigated by the combined use of structural and spectral characterizations,demonstrating that the photosensitizer CQDs contacted well with the BPEI modified TiO2 nanoparticles.The comparison characterizations revealed that BPEI facilitated the dissociation and transfer of excitons as an electron transfer channel.The as-prepared BTC composites benefited from the favorable interfacial contact and effective transfer of photo-generated charge carriers,and thus manifested superior photocatalytic activity to the TC composite.It is expected that this strategy would be extended to other wide band gap semiconductor photocatalyst systems and open up new possibilities in designing efficient CQDs-based semiconductor artificial light harvesting systems by interfacial optimization.展开更多
MicroRNAs(miRNAs) have been widely identified in porcine testicular tissues and implicated as crucial regulators of proliferation, apoptosis, and differentiation in porcine spermatogenesis related cells. However, the ...MicroRNAs(miRNAs) have been widely identified in porcine testicular tissues and implicated as crucial regulators of proliferation, apoptosis, and differentiation in porcine spermatogenesis related cells. However, the function roles of most of the miRNAs that have been identified in Sertoli cells are poorly understood. In the present study, six experiments were conducted to study the regulatory role of miR-10b in porcine immature Sertoli cells. In experiment 1, the results showed that the relative mRNA expression level of miR-10b in porcine testicular tissues decreased quadratically(P<0.001) with increasing age, while the relative mRNA expression level of DAZAP1 gene increased(P<0.001). In addition, the mRNA expression of miR-10b was negatively(P<0.01) correlated with DAZAP1 mRNA expression(r=–0.550). In experiment 2, the results from the bioinformatic analysis and a luciferase reporter assay demonstrated that miR-10b directly targeted the DAZAP1 gene in porcine immature Sertoli cells. DAZAP1 mRNA and protein expressions were both regulated(P<0.05) by miR-10b. In experiments 3 to 5, the over-expression of miR-10b or the siRNA-mediated knockdown of the DAZAP1 gene promoted(P<0.05) porcine immature Sertoli cell proliferation, as determined by the Cell Counting Kit-8(CCK-8) assay and the 5-Ethynyl-2′-deoxyuridine(EdU) assay. However, an annexin V-FITC/PI staining assay and the expression of cell survival-related genes indicated that over-expression of miR-10b or knockdown of DAZAP1 had no effect(P>0.05) on porcine immature Sertoli cell apoptosis. In experiment 6, the co-transfection treatment results showed that miR-10b promoted(P<0.05) porcine immature Sertoli cell proliferation by targeting DAZAP1 gene. Overall, these experiments demonstrated that miR-10b promotes porcine immature Sertoli cell proliferation by targeting the DAZAP1 gene.展开更多
MicroRNAs(miRNAs) are implicated in swine spermatogenesis via their regulations of cell proliferation, apoptosis, and differentiation. Recent studies indicated that miR-34 c is indispensable in the late steps of sperm...MicroRNAs(miRNAs) are implicated in swine spermatogenesis via their regulations of cell proliferation, apoptosis, and differentiation. Recent studies indicated that miR-34 c is indispensable in the late steps of spermatogenesis. However, whether miR-34 c plays similar important roles in immature porcine Sertoli cells remain unknown. In the present study, we conducted two experiments using a completely randomised design to study the function roles of miR-34 c. The results from experiment I demonstrated that the relative expression level of miR-34 c in swine testicular tissues increased(P=0.0017) quadratically with increasing age, while the relative expression level of SMAD family member 7(SMAD7) decreased(P=0.0009) with curve. Furthermore, miR-34 c expression levels showed a significant negative correlation(P=0.013) with SMAD7 gene expression levels. The results from experiment II indicated that miR-34 c directly targets the SMAD7 gene using a luciferase reporter assay, and suppresses(P<0.05) SMAD7 mRNA and protein expressions in immature porcine Sertoli cells. Overexpression of miR-34 c inhibited(P<0.05) proliferation and enhanced(P<0.05) apoptosis in the immature porcine Sertoli cells, which was supported by the results from the Cell Counting Kit-8(CCK-8) assay, the 5-Ethynyl-2′-deoxyuridine(EdU) assay, and the Annexin V-FITC/PI staining assay. Furthermore, knockdown of SMAD7 via small interfering RNA(siR NA) gave a similar result. It is concluded that miR-34 c inhibits proliferation and enhances apoptosis in immature porcine Sertoli cells by targeting the SMAD7 gene.展开更多
文摘Carbon quantum dots(CQDs)are emerging as the new-generation light absorber for solar energy conversion.However,the low photosensitization efficiency of CQDs is one of the current bottlenecks impeding their large-scale practical applications in photocatalysis.Therefore,developing a facile approach for the engineering and functionalization of CQDs-based composites to improve the photosensitization efficiency of CQDs is highly desirable.On account of the abundant functional groups,especially oxygen-containing functional groups such as carbonyl,carboxyl,and hydroxyl present on their surface,CQDs can be readily combined with various organic molecules or polymers as a surface passivation component to reduce the nonradioactive surface recombination of photo-generated charge carriers,thus enabling the CQDs to exhibit strong photoluminescence in the visible and near-infrared spectral regions.Consequently,polymer passivation has been demonstrated as an ideal strategy to make it accessible for improving the sensitization efficiency of CQDs in photocatalytic applications.Branched polyethylenimine(BPEI)is one of polymers that contains a high density of amine groups and exhibits high electron mobility,which can be used as an electron injection material at the interface of nanomaterials.Besides,the BPEI polymer with amino groups exhibiting positive charge has been utilized for designing heterogeneous catalysts by an electrostatic self-assembly strategy.Therefore,BPEI is expected to modify the surface of inorganic oxides semiconductor to enhance the photosensitization efficiency of CQDs under visible light.However,to date,the study in this regard has been still unavailable In this work,we developed a facile approach to engineer well-distributed CQDs via electrostatic interaction on BPEI passivated TiO2 composites(BTC)as photocatalysts.The BTC composites with an optimal loading of 5%(w,mass fraction)CQDs outperformed the TiO2/CQDs(TC)composite and referential BPEI/SiO2/CQDs(BSC)composites for the photoreduction of 4-nitroaniline under visible light irradiation.The structure of the fabricated BTC composites was systematically investigated by the combined use of structural and spectral characterizations,demonstrating that the photosensitizer CQDs contacted well with the BPEI modified TiO2 nanoparticles.The comparison characterizations revealed that BPEI facilitated the dissociation and transfer of excitons as an electron transfer channel.The as-prepared BTC composites benefited from the favorable interfacial contact and effective transfer of photo-generated charge carriers,and thus manifested superior photocatalytic activity to the TC composite.It is expected that this strategy would be extended to other wide band gap semiconductor photocatalyst systems and open up new possibilities in designing efficient CQDs-based semiconductor artificial light harvesting systems by interfacial optimization.
基金financially supported by the earmarked fund for China Agriculture Research System (CARS-36)the Hunan Provincial Natural Science Foundation of China (2018JJ2176 and 2018JJ3219)
文摘MicroRNAs(miRNAs) have been widely identified in porcine testicular tissues and implicated as crucial regulators of proliferation, apoptosis, and differentiation in porcine spermatogenesis related cells. However, the function roles of most of the miRNAs that have been identified in Sertoli cells are poorly understood. In the present study, six experiments were conducted to study the regulatory role of miR-10b in porcine immature Sertoli cells. In experiment 1, the results showed that the relative mRNA expression level of miR-10b in porcine testicular tissues decreased quadratically(P<0.001) with increasing age, while the relative mRNA expression level of DAZAP1 gene increased(P<0.001). In addition, the mRNA expression of miR-10b was negatively(P<0.01) correlated with DAZAP1 mRNA expression(r=–0.550). In experiment 2, the results from the bioinformatic analysis and a luciferase reporter assay demonstrated that miR-10b directly targeted the DAZAP1 gene in porcine immature Sertoli cells. DAZAP1 mRNA and protein expressions were both regulated(P<0.05) by miR-10b. In experiments 3 to 5, the over-expression of miR-10b or the siRNA-mediated knockdown of the DAZAP1 gene promoted(P<0.05) porcine immature Sertoli cell proliferation, as determined by the Cell Counting Kit-8(CCK-8) assay and the 5-Ethynyl-2′-deoxyuridine(EdU) assay. However, an annexin V-FITC/PI staining assay and the expression of cell survival-related genes indicated that over-expression of miR-10b or knockdown of DAZAP1 had no effect(P>0.05) on porcine immature Sertoli cell apoptosis. In experiment 6, the co-transfection treatment results showed that miR-10b promoted(P<0.05) porcine immature Sertoli cell proliferation by targeting DAZAP1 gene. Overall, these experiments demonstrated that miR-10b promotes porcine immature Sertoli cell proliferation by targeting the DAZAP1 gene.
基金financially supported by the earmarked fund for China Agriculture Research System (CARS-36)the Hunan Provincial Natural Science Foundation of China (2018JJ3219 and 2018JJ2176)the Excellent Doctoral Dissertation Cultivating Fund of Hunan Agricultural University, China (YB2015001)
文摘MicroRNAs(miRNAs) are implicated in swine spermatogenesis via their regulations of cell proliferation, apoptosis, and differentiation. Recent studies indicated that miR-34 c is indispensable in the late steps of spermatogenesis. However, whether miR-34 c plays similar important roles in immature porcine Sertoli cells remain unknown. In the present study, we conducted two experiments using a completely randomised design to study the function roles of miR-34 c. The results from experiment I demonstrated that the relative expression level of miR-34 c in swine testicular tissues increased(P=0.0017) quadratically with increasing age, while the relative expression level of SMAD family member 7(SMAD7) decreased(P=0.0009) with curve. Furthermore, miR-34 c expression levels showed a significant negative correlation(P=0.013) with SMAD7 gene expression levels. The results from experiment II indicated that miR-34 c directly targets the SMAD7 gene using a luciferase reporter assay, and suppresses(P<0.05) SMAD7 mRNA and protein expressions in immature porcine Sertoli cells. Overexpression of miR-34 c inhibited(P<0.05) proliferation and enhanced(P<0.05) apoptosis in the immature porcine Sertoli cells, which was supported by the results from the Cell Counting Kit-8(CCK-8) assay, the 5-Ethynyl-2′-deoxyuridine(EdU) assay, and the Annexin V-FITC/PI staining assay. Furthermore, knockdown of SMAD7 via small interfering RNA(siR NA) gave a similar result. It is concluded that miR-34 c inhibits proliferation and enhances apoptosis in immature porcine Sertoli cells by targeting the SMAD7 gene.
