Silk fibroin(SF)can be used to construct various stiff material interfaces to support bone formation.An essential preparatory step is to partially transform SF molecules from random coils toβ-sheets to render the mat...Silk fibroin(SF)can be used to construct various stiff material interfaces to support bone formation.An essential preparatory step is to partially transform SF molecules from random coils toβ-sheets to render the material water insoluble.However,the influence of the SF conformation on osteogenic cell behavior at the material interface remains unknown.Herein,three stiff SF substrates were prepared by varying theβ-sheet content(high,medium,and low).The substrates had a comparable chemical composition,surface topography,and wettability.When adsorbed fibronectin was used as a model cellular adhesive protein,the stability of the adsorbed protein-material interface,in terms of the surface stability of the SF substrates and the accompanying fibronectin detachment resistance,increased with the increasingβ-sheet content of the SF substrates.Furthermore,(i)larger areas of cytoskeleton-associated focal adhesions,(ii)higher orders of cytoskeletal organization and(iii)more elongated cell spreading were observed for bone marrow-derived mesenchymal stromal cells(BMSCs)cultured on SF substrates with high vs.lowβ-sheet contents,along with enhanced nuclear translocation and activation of YAP/TAZ and RUNX2.Consequently,osteogenic differentiation of BMSCs was stimulated on highβ-sheet substrates.These results indicated that theβ-sheet content influences osteogenic differentiation of BMSCs on SF materials in vitro by modulating the stability of the adsorbed protein-material interface,which proceeds via protein-focal adhesion-cytoskeleton links and subsequent intracellular mechanotransduction.Our findings emphasize the role of the stability of the adsorbed protein-material interface in cellular mechanotransduction and the perception of stiff SF substrates with differentβ-sheet contents,which should not be overlooked when engineering stiff biomaterials.展开更多
The oxygen evolution reaction(OER)plays an important role in the development of energy conversation and storage technologies including water splitting and metal-air batteries,where the development of electrocatalysts ...The oxygen evolution reaction(OER)plays an important role in the development of energy conversation and storage technologies including water splitting and metal-air batteries,where the development of electrocatalysts is paramount.In this study,cobalt-nickel phosphide/N-doped porous carbon polyhedron electrocatalysts(CoNiP/NC)were prepared by a facile two-step carbonization method and subsequent phosphorization calcination in an Ar atmosphere using cobalt-based zeolitic imidazolate frameworks(ZIFs)as precursors.Among the electrocatalysts obtained by controlling the carbonization and phosphorization temperature,the CoNiP/NC700 catalyst,where 700 refers to the calcination temperature(°C),exhibited superior electrocatalytic activity for the OER with an onset overpotential of approximate 220 mV and an overpotential of approximate 300 mV in alkaline solution at a current density of 10 mA/cm2.The CoNi/NC and Co/NC Samples were also tested for comparison and CoNiP/NC exhibited the better electrocatalytic activity at all the temperatures tested.The superior electrocatalytic activity of the phosphorization hybrid material can be attributed to the superior synergistic effect of Co,Ni,P and C due to their strong electron coupling interactions.The interconnected amorphous carbon anchored the active Co compounds to avoid aggregation and maintained conducting channels for electron transfer.The composite electrocatalyst prepared herein is a promising candidate for use in electrocatalytic OERs.展开更多
Vacuum gaps have rapid dynamic dielectric recovery speed while SF6 gaps have high insulation strength. The series-connected vacuum and SF6 gaps are used as the main switch(MS), which combines their advantages. The wor...Vacuum gaps have rapid dynamic dielectric recovery speed while SF6 gaps have high insulation strength. The series-connected vacuum and SF6 gaps are used as the main switch(MS), which combines their advantages. The work aims to verify the feasibility of serial vacuum and SF6 gaps in mechanical HVDC interruption. The test circuit of the dynamic dielectric recovery performance(DDRP) is set up. The DDRP is tested under free recovery condition by the high voltage pulse source. The DDRP of the vacuum circuit breaker(VCB) and SF6 gas circuit breaker(GCB) in DC interruption with active current injection is analyzed and compared. The test results indicate that the dielectric recovery duration of the VCB is below 30 μs while that of the GCB is above 100 μs. In order to achieve the cooperation between the VCB and GCB, a novel hybrid HVDC circuit breaker(CB) based on series-connected vacuum and SF6 gaps is proposed. The ‘voltage-zero’ duration is created by introducing the follow current loop and there more recovery time for the dielectric recovery of the MS. The voltage distribution is controlled by the voltage dividing method so that the VCB undertakes the initial transient recovery voltage(TRV) and the later TRV is took by the GCB. The theoretical synergy characteristic of the novel HVDC CB is obtained. The paper supplies a new method to improve the custom mechanical HVDC CB, which is useful to achieve the HVDC CB with less serial breaks.展开更多
The emerging rocking-chair aqueous zinc-ion battery(AZIB)configuration provides a promising approach for realizing their practical applications by avoiding the critical drawbacks of Zn metal anodes including unsatisfa...The emerging rocking-chair aqueous zinc-ion battery(AZIB)configuration provides a promising approach for realizing their practical applications by avoiding the critical drawbacks of Zn metal anodes including unsatisfactory Coulombic efficiency and low Zn utilization.Therefore,exploiting appropriate insertion-type anodes with fast charge-transfer kinetics is of great importance,and many modifications focusing on the improvement of electron transport and bulk Zn^(2+)diffusion have been proposed.However,the interfacial Zn^(2+)transfer determined by the desolvation process actually dominates the kinetics of overall battery reactions,which is mainly overlooked.Herein,the interlayer structure of Mo S_(2)is rationally co-intercalated with water and ethylene glycol(EG)molecules(Mo S2@EG),giving rise to a fast non-desolvation Zn^(2+)storage mechanism,which is verified by the extraordinarily smaller activation energy of interfacial Zn^(2+)transfer(4.66 k J mol^(-1))compared with that of pristine Mo S_(2)(56.78 k J mol^(-1)).Furthermore,the results of theoretical calculations,in-situ Raman and ex-situ characterizations also indicate the enhanced structural integrity of Mo S2@EG during cycling due to the enlarged interlayer spacing and charge screening effect induced by interlaminar EG molecules.Consequently,the Mo S_(2)@EG anode enables excellent cycling stability of both high-energy-density Mo_S2@EG||PVO(polyaniline intercalated V_(2)O_(5))and high-voltage Mo S2@EG||Na_(3)V_(2)(PO_(4))_2O_(2)F(NVPF)full batteries with neglectable capacity decay at-20℃.展开更多
The therapeutic precision and clinical applicability of drug-eluting coatings can be substantially improved by facilitating tunable drug delivery.However,the design of coatings which allows for precise control over dr...The therapeutic precision and clinical applicability of drug-eluting coatings can be substantially improved by facilitating tunable drug delivery.However,the design of coatings which allows for precise control over drug release kinetics is still a major challenge.Here,a double-layered silk fibroin(SF)coating system was constructed by sequential electrophoretic deposition.A mixture of dissolved Bombyx mori SF(bmSF)molecules and pre-made bmSF nanospheres at different ratios was deposited as under-layer.Subsequently,this underlayer was covered by a top-layer comprising Antheraea pernyi SF(apSF)molecules(rich in arginylglycylaspartic acid,RGD)to improve the cellular response of the resulting double-layered coatings.Additionally,model drug doxycycline was either pre-mixed with dissolved bmSF molecules or pre-loaded into pre-made bmSF nanospheres at the same amount before their mixing and deposition.The thickness and nanosphere content of the under-layer architecture were proportional to the deposition time and nanosphere concentration in precursor mixtures,respectively.The surface topography,wettability,degradation rate and adhesion strength were comparable within the double-layered coating system.As expected,RGD-rich apSF top-layer improved cell adhesion,spreading and proliferation compared with bmSF top-layer.Furthermore,the amount and duration of drug release increased linearly with increasing nanosphere concentration at fixed deposition time,whereas drug release amount increased linearly with increasing deposition time.These results indicate that the dosage and kinetics of loaded drugs can be quantitatively tailored by altering nanosphere concentration and deposition time as main processing parameters.Overall,this study illustrates the strong potential of pre-defining coating architecture to facilitate control over drug delivery.展开更多
Anaplastic thyroid cancer(ATC)is a rare but highly lethal disease.ATCs are resistant to standard therapies and are extremely difficult to manage.The stepwise cell dedifferentiation results in the impairment of the iod...Anaplastic thyroid cancer(ATC)is a rare but highly lethal disease.ATCs are resistant to standard therapies and are extremely difficult to manage.The stepwise cell dedifferentiation results in the impairment of the iodine-metabolizing machinery and the infeasibility of radioiodine treatment in ATC.Hence,reinducing iodine-metabolizing gene expression to restore radioiodine avidity is considered as a promising strategy to fight against ATC.In the present study,capsaicin(CAP),a natural potent transient receptor potential vanilloid type 1(TRPV1)agonist,was discovered to reinduce ATC cell differentiation and to increase the expression of thyroid transcription factors(TTFs including TTF-1,TTF-2,and PAX8)and iodine-metabolizing proteins,including thyroidstimulating hormone receptor(TSHR),thyroid peroxidase,and sodium iodine symporter(NIS),in two ATC cell lines,8505C and FRO.Strikingly,CAP treatment promoted NIS glycosylation and its membrane trafficking,resulting in a significant enhancement of radioiodine uptake of ATC cells in vitro.Mechanistically,CAP-activated TRPV1 channel and subsequently triggered Ca2þinflux,cyclic adenosine monophosphate(cAMP)generation,and cAMP-responsive element-binding protein(CREB)signal activation.Next,CREB recognized and bound to the promoter of SLC5A5 to facilitate its transcription.Moreover,the TRPV1 antagonist CPZ,the calcium chelator BAPTA,and the PKA inhibitor H-89 effectively alleviated the redifferentiation exerted by CAP,demonstrating that CAP might improve radioiodine avidity through the activation of the TRPV1–Ca2þ/cAMP/PKA/CREB signaling pathway.In addition,our study indicated that CAP might trigger a novel cascade to redifferentiate ATC cells and provide unprecedented opportunities for radioiodine therapy in ATC,bypassing canonical TSH–TSHR pathway.展开更多
基金supported by the National Key R&D Program of China(2017YFC1104301,to L.C.)the National Natural Science Foundation of China for Distinguished Young Scholars(31725011,to L.C.)the China Scholarship Council(201606160095,to X.C.)。
文摘Silk fibroin(SF)can be used to construct various stiff material interfaces to support bone formation.An essential preparatory step is to partially transform SF molecules from random coils toβ-sheets to render the material water insoluble.However,the influence of the SF conformation on osteogenic cell behavior at the material interface remains unknown.Herein,three stiff SF substrates were prepared by varying theβ-sheet content(high,medium,and low).The substrates had a comparable chemical composition,surface topography,and wettability.When adsorbed fibronectin was used as a model cellular adhesive protein,the stability of the adsorbed protein-material interface,in terms of the surface stability of the SF substrates and the accompanying fibronectin detachment resistance,increased with the increasingβ-sheet content of the SF substrates.Furthermore,(i)larger areas of cytoskeleton-associated focal adhesions,(ii)higher orders of cytoskeletal organization and(iii)more elongated cell spreading were observed for bone marrow-derived mesenchymal stromal cells(BMSCs)cultured on SF substrates with high vs.lowβ-sheet contents,along with enhanced nuclear translocation and activation of YAP/TAZ and RUNX2.Consequently,osteogenic differentiation of BMSCs was stimulated on highβ-sheet substrates.These results indicated that theβ-sheet content influences osteogenic differentiation of BMSCs on SF materials in vitro by modulating the stability of the adsorbed protein-material interface,which proceeds via protein-focal adhesion-cytoskeleton links and subsequent intracellular mechanotransduction.Our findings emphasize the role of the stability of the adsorbed protein-material interface in cellular mechanotransduction and the perception of stiff SF substrates with differentβ-sheet contents,which should not be overlooked when engineering stiff biomaterials.
文摘The oxygen evolution reaction(OER)plays an important role in the development of energy conversation and storage technologies including water splitting and metal-air batteries,where the development of electrocatalysts is paramount.In this study,cobalt-nickel phosphide/N-doped porous carbon polyhedron electrocatalysts(CoNiP/NC)were prepared by a facile two-step carbonization method and subsequent phosphorization calcination in an Ar atmosphere using cobalt-based zeolitic imidazolate frameworks(ZIFs)as precursors.Among the electrocatalysts obtained by controlling the carbonization and phosphorization temperature,the CoNiP/NC700 catalyst,where 700 refers to the calcination temperature(°C),exhibited superior electrocatalytic activity for the OER with an onset overpotential of approximate 220 mV and an overpotential of approximate 300 mV in alkaline solution at a current density of 10 mA/cm2.The CoNi/NC and Co/NC Samples were also tested for comparison and CoNiP/NC exhibited the better electrocatalytic activity at all the temperatures tested.The superior electrocatalytic activity of the phosphorization hybrid material can be attributed to the superior synergistic effect of Co,Ni,P and C due to their strong electron coupling interactions.The interconnected amorphous carbon anchored the active Co compounds to avoid aggregation and maintained conducting channels for electron transfer.The composite electrocatalyst prepared herein is a promising candidate for use in electrocatalytic OERs.
基金supported by National Natural Science Foundation of China (Nos. 51407163, 51777025)National Rail Transportation Electrification and Automation Engineering Technology Research Center (No. NEEC-2017B07)+1 种基金China Postdoctoral Science Foundation (No. 2017M622370)Key scientific research projects of colleges and universities in Henan(16A470014, 19A470008)
文摘Vacuum gaps have rapid dynamic dielectric recovery speed while SF6 gaps have high insulation strength. The series-connected vacuum and SF6 gaps are used as the main switch(MS), which combines their advantages. The work aims to verify the feasibility of serial vacuum and SF6 gaps in mechanical HVDC interruption. The test circuit of the dynamic dielectric recovery performance(DDRP) is set up. The DDRP is tested under free recovery condition by the high voltage pulse source. The DDRP of the vacuum circuit breaker(VCB) and SF6 gas circuit breaker(GCB) in DC interruption with active current injection is analyzed and compared. The test results indicate that the dielectric recovery duration of the VCB is below 30 μs while that of the GCB is above 100 μs. In order to achieve the cooperation between the VCB and GCB, a novel hybrid HVDC circuit breaker(CB) based on series-connected vacuum and SF6 gaps is proposed. The ‘voltage-zero’ duration is created by introducing the follow current loop and there more recovery time for the dielectric recovery of the MS. The voltage distribution is controlled by the voltage dividing method so that the VCB undertakes the initial transient recovery voltage(TRV) and the later TRV is took by the GCB. The theoretical synergy characteristic of the novel HVDC CB is obtained. The paper supplies a new method to improve the custom mechanical HVDC CB, which is useful to achieve the HVDC CB with less serial breaks.
基金supported by the National Natural Science Foundation of China(22109030,22021001)the Fundamental Research Funds for the Central Universities(20720220073)+3 种基金the Key Research and Development Program of Yunnan Province(202103AA080019)the Fujian Industrial Technology Development and Application Plan(2022I0002)the Guangdong Basic and Applied Basic Research Foundation(2019A1515111069,2021A1515010177)the financial support from Guangdong Basic and Applied Basic Research Foundation(2020A1515010886)。
文摘The emerging rocking-chair aqueous zinc-ion battery(AZIB)configuration provides a promising approach for realizing their practical applications by avoiding the critical drawbacks of Zn metal anodes including unsatisfactory Coulombic efficiency and low Zn utilization.Therefore,exploiting appropriate insertion-type anodes with fast charge-transfer kinetics is of great importance,and many modifications focusing on the improvement of electron transport and bulk Zn^(2+)diffusion have been proposed.However,the interfacial Zn^(2+)transfer determined by the desolvation process actually dominates the kinetics of overall battery reactions,which is mainly overlooked.Herein,the interlayer structure of Mo S_(2)is rationally co-intercalated with water and ethylene glycol(EG)molecules(Mo S2@EG),giving rise to a fast non-desolvation Zn^(2+)storage mechanism,which is verified by the extraordinarily smaller activation energy of interfacial Zn^(2+)transfer(4.66 k J mol^(-1))compared with that of pristine Mo S_(2)(56.78 k J mol^(-1)).Furthermore,the results of theoretical calculations,in-situ Raman and ex-situ characterizations also indicate the enhanced structural integrity of Mo S2@EG during cycling due to the enlarged interlayer spacing and charge screening effect induced by interlaminar EG molecules.Consequently,the Mo S_(2)@EG anode enables excellent cycling stability of both high-energy-density Mo_S2@EG||PVO(polyaniline intercalated V_(2)O_(5))and high-voltage Mo S2@EG||Na_(3)V_(2)(PO_(4))_2O_(2)F(NVPF)full batteries with neglectable capacity decay at-20℃.
基金X.C.is funded by China Scholarship Council(Project No.201606160095)。
文摘The therapeutic precision and clinical applicability of drug-eluting coatings can be substantially improved by facilitating tunable drug delivery.However,the design of coatings which allows for precise control over drug release kinetics is still a major challenge.Here,a double-layered silk fibroin(SF)coating system was constructed by sequential electrophoretic deposition.A mixture of dissolved Bombyx mori SF(bmSF)molecules and pre-made bmSF nanospheres at different ratios was deposited as under-layer.Subsequently,this underlayer was covered by a top-layer comprising Antheraea pernyi SF(apSF)molecules(rich in arginylglycylaspartic acid,RGD)to improve the cellular response of the resulting double-layered coatings.Additionally,model drug doxycycline was either pre-mixed with dissolved bmSF molecules or pre-loaded into pre-made bmSF nanospheres at the same amount before their mixing and deposition.The thickness and nanosphere content of the under-layer architecture were proportional to the deposition time and nanosphere concentration in precursor mixtures,respectively.The surface topography,wettability,degradation rate and adhesion strength were comparable within the double-layered coating system.As expected,RGD-rich apSF top-layer improved cell adhesion,spreading and proliferation compared with bmSF top-layer.Furthermore,the amount and duration of drug release increased linearly with increasing nanosphere concentration at fixed deposition time,whereas drug release amount increased linearly with increasing deposition time.These results indicate that the dosage and kinetics of loaded drugs can be quantitatively tailored by altering nanosphere concentration and deposition time as main processing parameters.Overall,this study illustrates the strong potential of pre-defining coating architecture to facilitate control over drug delivery.
基金supported by grants from the National Natural Science Foundation of China(81972503 and 82103656).
文摘Anaplastic thyroid cancer(ATC)is a rare but highly lethal disease.ATCs are resistant to standard therapies and are extremely difficult to manage.The stepwise cell dedifferentiation results in the impairment of the iodine-metabolizing machinery and the infeasibility of radioiodine treatment in ATC.Hence,reinducing iodine-metabolizing gene expression to restore radioiodine avidity is considered as a promising strategy to fight against ATC.In the present study,capsaicin(CAP),a natural potent transient receptor potential vanilloid type 1(TRPV1)agonist,was discovered to reinduce ATC cell differentiation and to increase the expression of thyroid transcription factors(TTFs including TTF-1,TTF-2,and PAX8)and iodine-metabolizing proteins,including thyroidstimulating hormone receptor(TSHR),thyroid peroxidase,and sodium iodine symporter(NIS),in two ATC cell lines,8505C and FRO.Strikingly,CAP treatment promoted NIS glycosylation and its membrane trafficking,resulting in a significant enhancement of radioiodine uptake of ATC cells in vitro.Mechanistically,CAP-activated TRPV1 channel and subsequently triggered Ca2þinflux,cyclic adenosine monophosphate(cAMP)generation,and cAMP-responsive element-binding protein(CREB)signal activation.Next,CREB recognized and bound to the promoter of SLC5A5 to facilitate its transcription.Moreover,the TRPV1 antagonist CPZ,the calcium chelator BAPTA,and the PKA inhibitor H-89 effectively alleviated the redifferentiation exerted by CAP,demonstrating that CAP might improve radioiodine avidity through the activation of the TRPV1–Ca2þ/cAMP/PKA/CREB signaling pathway.In addition,our study indicated that CAP might trigger a novel cascade to redifferentiate ATC cells and provide unprecedented opportunities for radioiodine therapy in ATC,bypassing canonical TSH–TSHR pathway.
