Alloying and nanostructuring are two strategies used to facilitate the efficient electrocatalysis of the oxygen reduction reaction(ORR)by Pt,where the high index surfaces(HISs)of Pt exhibit superior activity for ORR.H...Alloying and nanostructuring are two strategies used to facilitate the efficient electrocatalysis of the oxygen reduction reaction(ORR)by Pt,where the high index surfaces(HISs)of Pt exhibit superior activity for ORR.Here,we report the fabrication of PtCu3 nanodendrites possessing rich spiny branches exposing n(111)×(110)HISs.The dendrites were formed through an etching‐modulated seeding and growing strategy.Specifically,an oxidative atmosphere was initially applied to form the concaved nanocubes of the Pt‐Cu seeds,which was then switched to an inert atmosphere to promote an explosive growth of dendrites.Separately,the oxidative or inert atmosphere failed to produce this hyperbranched structure.Electrochemical dealloying of the PtCu3 nanodendrites produced Pt3Cu shells with Pt‐rich surfaces where HIS‐exposed dendrite structures were maintained.The resulting PtCu_(3)@Pt_(3)Cu@Pt nanodendrites in 0.1 M HClO4 exhibited excellent mass and area specific activities for ORR,which were 14 and 24 times higher than that of commercial Pt/C,respectively.DFT calculations revealed that Cu alloying and HISs both contributed to the significantly enhanced activity of Pt,and that the oxygen binding energy on the step sites of HISs on the PtCu_(3)@Pt_(3)Cu@Pt nanodendrites approached the optimal value to achieve a near peak‐top ORR activity.展开更多
We report a fast in situ seeding approach based on zinc（II） porphyrin （ZnP） under white light irradiation, leading to uniform spherical platinum nanodendrites with tunable sizes. The platinum nanodendrites exhibit...We report a fast in situ seeding approach based on zinc（II） porphyrin （ZnP） under white light irradiation, leading to uniform spherical platinum nanodendrites with tunable sizes. The platinum nanodendrites exhibit significantly improved electrocatalytic activities toward oxygen reduction reaction （ORR） and methanol oxidation reaction （MOR） compared with commercial platinum black.展开更多
The causative agent of tuberculosis,Mycobacterium tuberculosis,is one of the most successful of human pathogens.It can evade the host immune response and establish a persistent infection or enter a dormant state withi...The causative agent of tuberculosis,Mycobacterium tuberculosis,is one of the most successful of human pathogens.It can evade the host immune response and establish a persistent infection or enter a dormant state within the host which can be reactivated if the host becomes immuno-compromised.Both of these features are major obstacles to tuberculosis eradication.Dormancy and reactivation of M.tuberculosis are tightly coordinated dynamic processes involving numerous genes and their products.Molecular mechanisms underlying M.tuberculosis persistence may provide an opportunity for the discovery of effective drug targets for tuberculosis control.Here,we review the genes required for M.tuberculosis persistence and propose a regulatory network for the action of these genes using text mining.This should provide fresh insights into the persistence mechanisms of M.tuberculosis and suggest candidates for new drug targets and immune intervention.展开更多
Microparticles have a demonstrated value for drug delivery systems. The attempts to develop this tech- nology focus on the generation of featured microparticles for improving the function of the systems. Here, we pres...Microparticles have a demonstrated value for drug delivery systems. The attempts to develop this tech- nology focus on the generation of featured microparticles for improving the function of the systems. Here, we present a new type of microparticles with gelatin methacrylate （GelMa） cores and poly（L-lactide-co-glycolide） （PLGA） shells for syn- ergistic and sustained drug delivery applications. The mi- croparticles were fabricated by using GelMa aqueous solu- tion and PLGA oil solution as the raw materials of the mi- croflnidic double emulsion templates, in which hydrophilic and hydrophobic actives, such as doxorubicin hydrochloride （DOX, hydrophilic） and camptothecine （CPT, hydrophobic）, could be loaded respectively. As the inner cores were poly- merized in the microfluidics when the double emulsions were formed, the hydrophilic actives could be trapped in the cores with high efficiency, and the rupture or fusion of the cores could be avoided during the solidification of the micropar- ticle shells with other actives. The size and component of the microparticles can be easily and precisely adjusted by ma- nipulating the flow solutions during the microfluidic emulsi- fication. Because of the solid structure of the resultant mi- croparticles, the encapsulated actives were released from the delivery systems only with the degradation of the biopolymer layers, and thus the burst release of the actives was avoided. These features of the microparticles make them ideal for drug delivery applications.展开更多
文摘Alloying and nanostructuring are two strategies used to facilitate the efficient electrocatalysis of the oxygen reduction reaction(ORR)by Pt,where the high index surfaces(HISs)of Pt exhibit superior activity for ORR.Here,we report the fabrication of PtCu3 nanodendrites possessing rich spiny branches exposing n(111)×(110)HISs.The dendrites were formed through an etching‐modulated seeding and growing strategy.Specifically,an oxidative atmosphere was initially applied to form the concaved nanocubes of the Pt‐Cu seeds,which was then switched to an inert atmosphere to promote an explosive growth of dendrites.Separately,the oxidative or inert atmosphere failed to produce this hyperbranched structure.Electrochemical dealloying of the PtCu3 nanodendrites produced Pt3Cu shells with Pt‐rich surfaces where HIS‐exposed dendrite structures were maintained.The resulting PtCu_(3)@Pt_(3)Cu@Pt nanodendrites in 0.1 M HClO4 exhibited excellent mass and area specific activities for ORR,which were 14 and 24 times higher than that of commercial Pt/C,respectively.DFT calculations revealed that Cu alloying and HISs both contributed to the significantly enhanced activity of Pt,and that the oxygen binding energy on the step sites of HISs on the PtCu_(3)@Pt_(3)Cu@Pt nanodendrites approached the optimal value to achieve a near peak‐top ORR activity.
基金Acknowledgements This work was partially supported by the National Basic Research Program （973 Program） of China （No. 2012CB215500）, the National High-tech R＆D Program（863 Program） of China （No. 2011AA11A273）, and the National Natural Science Foundation of China （NSFC, Nos. 21003114 and 21103163）. The authors thank Professor John A. Shelnutt at Georgia University, USA for fruitful discussions.
文摘We report a fast in situ seeding approach based on zinc（II） porphyrin （ZnP） under white light irradiation, leading to uniform spherical platinum nanodendrites with tunable sizes. The platinum nanodendrites exhibit significantly improved electrocatalytic activities toward oxygen reduction reaction （ORR） and methanol oxidation reaction （MOR） compared with commercial platinum black.
基金supported by the National Key Infectious Disease Project (Grant Nos.2008ZX10003-006 and 2008ZX10003-001)the Excellent PhD Thesis Fellowship of Southwest University(Grant Nos.kb2009010 and ky2009009)+2 种基金the Fundamental Research Funds for the Central Universities (Grant No.XDJK2009A003)the Natural Science Foundation Project of CQ CSTC(Grant No.CSTC,2010BB5002)the National Natural Science Foundation of China(Grant No.81071316)
文摘The causative agent of tuberculosis,Mycobacterium tuberculosis,is one of the most successful of human pathogens.It can evade the host immune response and establish a persistent infection or enter a dormant state within the host which can be reactivated if the host becomes immuno-compromised.Both of these features are major obstacles to tuberculosis eradication.Dormancy and reactivation of M.tuberculosis are tightly coordinated dynamic processes involving numerous genes and their products.Molecular mechanisms underlying M.tuberculosis persistence may provide an opportunity for the discovery of effective drug targets for tuberculosis control.Here,we review the genes required for M.tuberculosis persistence and propose a regulatory network for the action of these genes using text mining.This should provide fresh insights into the persistence mechanisms of M.tuberculosis and suggest candidates for new drug targets and immune intervention.
基金supported by the National Natural Science Foundation of China (21473029 and 51522302) the NSAF Foundation of China (U1530260)+4 种基金the National Science Foundation of Jiangsu (BK20140028) the Program for New Century Excellent Talents in Universitythe Scientific Research Foundation of Southeast UniversityFoundation of Jiangsu Cancer Hospital (ZN201609)Beijing Medical Award Foundation (YJHYXKYJJ-433)
文摘Microparticles have a demonstrated value for drug delivery systems. The attempts to develop this tech- nology focus on the generation of featured microparticles for improving the function of the systems. Here, we present a new type of microparticles with gelatin methacrylate （GelMa） cores and poly（L-lactide-co-glycolide） （PLGA） shells for syn- ergistic and sustained drug delivery applications. The mi- croparticles were fabricated by using GelMa aqueous solu- tion and PLGA oil solution as the raw materials of the mi- croflnidic double emulsion templates, in which hydrophilic and hydrophobic actives, such as doxorubicin hydrochloride （DOX, hydrophilic） and camptothecine （CPT, hydrophobic）, could be loaded respectively. As the inner cores were poly- merized in the microfluidics when the double emulsions were formed, the hydrophilic actives could be trapped in the cores with high efficiency, and the rupture or fusion of the cores could be avoided during the solidification of the micropar- ticle shells with other actives. The size and component of the microparticles can be easily and precisely adjusted by ma- nipulating the flow solutions during the microfluidic emulsi- fication. Because of the solid structure of the resultant mi- croparticles, the encapsulated actives were released from the delivery systems only with the degradation of the biopolymer layers, and thus the burst release of the actives was avoided. These features of the microparticles make them ideal for drug delivery applications.
