Mitochondria undergo morphological changes during spermatogenesis in some animals.The mechanism and role of mitochondrial morphology regulation,however,remain somewhat unclear.In this study,we analyzed the molecular c...Mitochondria undergo morphological changes during spermatogenesis in some animals.The mechanism and role of mitochondrial morphology regulation,however,remain somewhat unclear.In this study,we analyzed the molecular characteristics,expression dynamics and subcellular localization of optic atrophy protein 1(OPA1),a mitochondrial fusion and cristae maintenance-related protein,to reveal the possible regulatory mechanisms underlying mitochondrial morphology in Phascolosoma esculenta spermiogenesis.The full-length cDNA of the P.esculenta opa1 gene(Pe-opa1)is 3743 bp in length and encodes 975 amino acids.The Pe-OPA1 protein is highly conservative and includes a transmembrane domain,a GTPase domain,two helical bundle domains,and a lipid-interacting stalk.Gene and protein expression was higher in the coelomic fluid(a site of spermatid development)of male P.esculenta and increased first and then decreased from March to December.Moreover,their expression during the breeding stage was significantly higher than during the non-breeding stage,suggesting that Pe-OPA1 is involved in P.esculenta reproduction.The Pe-OPA1 protein was more abundant in components consisting of many spermatids than in components without,indicating that Pe-OPA1 mainly plays a role in the spermatid in coelomic fluid.Moreover,Pe-OPA1 was mainly detected in the spermatid mitochondria.Immunofluorescence experiments showed that the Pe-OPA1 are constitutively expressed and co-localized with mitochondria during spermiogenesis,suggesting its involvement in P.esculenta spermiogenesis.These results provide evidence for Pe-OPA1's involvement in the regulation of mitochondrial morphology during spermiogenesis.展开更多
In this article, we provided a one-step hydrothermal method to prepare composite AIZr pillaring agents, and synthesized AlZr-pillared clays （AIZr-PILC） via ion exchange. Compared with conventional methods, our metho...In this article, we provided a one-step hydrothermal method to prepare composite AIZr pillaring agents, and synthesized AlZr-pillared clays （AIZr-PILC） via ion exchange. Compared with conventional methods, our method successfully shortened synthetic routes and greatly reduced consumption of the materials. Then, A1Zr-PILC-supported manganese and cerium oxide catalysts were obtained by impregnation method. The compositions and properties of these catalysts were characterized by some technical means. The energy dispersive X-ray spectroscopy clearly shows the existence of Mn, Ce, and O, which indicates the successful loading of the active components on the surface of AIZr-PILC. Meanwhile, the results of X- ray diffraction （XRD） and N2 adsorption experiments demonstrate that the synthesized A1Zr-PILC out- performs the raw clays （Na-mmt） and mononuclear AI-PILC in the catalytic combustion of chloroben- zene. XRD and high-resolution transmission electron microscopy also proves that the high activity of them is related to the high dispersion of the oxides and the exposure of more active sites. H2-temper- ature-programmed reduction shows that cerium can promote the redox cycles of the manganese system through the strong interactions between MnO2, CeO2 and AIZr-PILC. In particular, MnCe（9：1 ）/AIZr-PILC shows the best catalytic activity in the catalytic combustion of chlorobenzene.展开更多
The electronic conductivity and durability of porous carbon supports can be improved by increasing the degree of graphitization in the material;however,the preparation of highly graphitic porous carbon using conventio...The electronic conductivity and durability of porous carbon supports can be improved by increasing the degree of graphitization in the material;however,the preparation of highly graphitic porous carbon using conventional furnaces remains a significant challenge.Herein,we demonstrate a universal and highly efficient carbothermal shock strategy that significantly improves the degree of graphitization of porous carbon supports,including bowl‐like carbon,hollow carbon spheres,ZIF8‐derived carbon,BP2000,and Ketjen EC 300J.Taking bowl‐like carbon as an example,we illustrate the synthesis of a graphitized bowl‐like carbon(G‐BC‐S)support and evaluate the performance of PtCo/G‐BC‐S in the oxygen reduction reaction(ORR)in rotating disk electrodes(RDE)and H_(2)/air PEM single cells.PtCo/G‐BC‐S exhibits faster ORR kinetics than PtCo/BC and Pt/C,with little loss of activity(25%)and only 13 mV of E1/2 decay after 20000 cycles accelerated stress testing under 1.0-1.5 V vs.a reversible hydrogen electrode(RHE).The significantly enhanced performance of the PtCo/G‐BC‐S catalyst arises from the high activity and chemical/structural stability of the PtCo intermetallic nanoparticles and from the high degree of graphitization and well‐defined porous structure of the bowl‐like carbon support,which confers excellent electrical conductivity and oxygen transport properties.This study provides a reliable and universal strategy for the development of high‐performance porous carbon supports for practical applications in fuel cells.展开更多
Workload prediction is critical in enabling proactive resource management of cloud applications.Accurate workload prediction is valuable for cloud users and providers as it can effectively guide many practices,such as...Workload prediction is critical in enabling proactive resource management of cloud applications.Accurate workload prediction is valuable for cloud users and providers as it can effectively guide many practices,such as performance assurance,cost reduction,and energy consumption optimization.However,cloud workload prediction is highly challenging due to the complexity and dynamics of workloads,and various solutions have been proposed to enhance the prediction behavior.This paper aims to provide an in-depth understanding and categorization of existing solutions through extensive literature reviews.Unlike existing surveys,for the first time,we comprehensively sort out and analyze the development landscape of workload prediction from a new perspective,i.e.,application-oriented rather than prediction methodologies per se.Specifically,we first introduce the basic features of workload prediction,and then analyze and categorize existing efforts based on two significant characteristics of cloud applications:variability and heterogeneity.Furthermore,we also investigate how workload prediction is applied to resource management.Finally,open research opportunities in workload prediction are highlighted to foster further advancements.展开更多
Enhancing the selectivity of noble metal catalysts through electronic modulation is important for academic research and chemical industrial processes.Herein,we report a facile sacrificial template strategy for the syn...Enhancing the selectivity of noble metal catalysts through electronic modulation is important for academic research and chemical industrial processes.Herein,we report a facile sacrificial template strategy for the synthesis of PdZn intermetallic compound(3-4 nm)highly distributed in ZnO/nitrogen-decorated carbon hollow spheres(PdZn-ZnO/NCHS)to optimize the selectivity of Pd catalysts,which involves carbonization of a core-shell structured polystyrene(PS)@ZIF-8 precursor in an inert atmosphere,impregnation Pd precursor,and subsequent H2 reduction treatment.Due to the unique structural and compositional features,the developed PdZn-ZnO/NCHS delivers an excellent catalytic performance for the semihydrogenation of 2-methyl-3-butyn-2-ol(MBY)to 2-methyl-3-buten-2-ol(MBE)with high activity(>99%),high selectivity(96%),and good recyclability,outperforming the analog Pd on ZnO(Pd/ZnO)as well as the supported Pd nanoparticles(Pd/C and Pd/NC).Density functional theory(DFT)calculations reveal that the presence of Znδ+species in PdZn-ZnO/NCHS alters the adsorption modes of reactant and product,leading to a decrease of the adsorption strength and an enhancement of the energy barrier for overhydrogenation,which results in a kinetic favor for the selective transformation of MBY to MBE.In addition,PdZn-ZnO/NCHS was also very effective for the partial hydrogenation of dehydrolinalool to hydrolinalool.展开更多
Designing and synthesizing high-efficiency non-precious metal-based catalysts having uniform active sites increases the reactivity and selectivity of materials and provides a platform for an in-depth understanding of ...Designing and synthesizing high-efficiency non-precious metal-based catalysts having uniform active sites increases the reactivity and selectivity of materials and provides a platform for an in-depth understanding of their catalytic reaction mechanism.In this study,we provided an approach for fabricating isolated nickel single-atom sites(Ni SAs)with high loading(4.9 wt.%)stabilized on nitrogen-doped hollow carbon spheres(NHCS)using a core–shell structured Zn/Ni bimetallic zeolitic imidazolate framework(ZIF)composite as the sacrificial template.The as-fabricated Ni SAs/NHCS catalyst shows superior activity,selectivity,and recycling durability for the catalytic transfer hydrogenation of nitrobenzene to aniline,thus achieving 100%yield of aniline with a turn-over frequency(TOF)value as high as 29.9 h^(−1) under mild conditions.This TOF value is considerably superior to the supported Ni nanoparticle catalysts.The experiments designed show that the hollow structure feature of NHCS facilitates accessible active sites and mass transfer,which thus contributes to the enhancement of the catalytic performance of Ni SAs/NHCS.Density functional theory calculations show the high chemo-selectivity and activity of the Ni SAs catalyst,arising from the unique role of the single Ni-N3 site on simultaneously activating the H donor(N_(2)H_(4))and substrate,as well as the hydrogenation of the–NOH group as the rate-determining step.展开更多
基金the Ningbo Science and Technology Plan Projects(Nos.2019B10016,2016C10004)the Major Science and Technology Projects in Zhejiang Province(No.2011C12013)+1 种基金the Natural Science Foundation of Zhejiang Province(No.LY18C190007)the Collaborative Innovation Center for Zhejiang Marine High-efficiency and Healthy Aquaculture,the K.C.Wong Magna Fund in Ningbo University。
文摘Mitochondria undergo morphological changes during spermatogenesis in some animals.The mechanism and role of mitochondrial morphology regulation,however,remain somewhat unclear.In this study,we analyzed the molecular characteristics,expression dynamics and subcellular localization of optic atrophy protein 1(OPA1),a mitochondrial fusion and cristae maintenance-related protein,to reveal the possible regulatory mechanisms underlying mitochondrial morphology in Phascolosoma esculenta spermiogenesis.The full-length cDNA of the P.esculenta opa1 gene(Pe-opa1)is 3743 bp in length and encodes 975 amino acids.The Pe-OPA1 protein is highly conservative and includes a transmembrane domain,a GTPase domain,two helical bundle domains,and a lipid-interacting stalk.Gene and protein expression was higher in the coelomic fluid(a site of spermatid development)of male P.esculenta and increased first and then decreased from March to December.Moreover,their expression during the breeding stage was significantly higher than during the non-breeding stage,suggesting that Pe-OPA1 is involved in P.esculenta reproduction.The Pe-OPA1 protein was more abundant in components consisting of many spermatids than in components without,indicating that Pe-OPA1 mainly plays a role in the spermatid in coelomic fluid.Moreover,Pe-OPA1 was mainly detected in the spermatid mitochondria.Immunofluorescence experiments showed that the Pe-OPA1 are constitutively expressed and co-localized with mitochondria during spermiogenesis,suggesting its involvement in P.esculenta spermiogenesis.These results provide evidence for Pe-OPA1's involvement in the regulation of mitochondrial morphology during spermiogenesis.
基金Project supported by 2017 National Innovation Training Program for College Students(201710349004)the Project of Shaoxing University(2015LG1002)+1 种基金2017 Zhejiang Province Innovation Training Program for College Students(2017R428024)National Natural Science Foundation of China(21577094)
文摘In this article, we provided a one-step hydrothermal method to prepare composite AIZr pillaring agents, and synthesized AlZr-pillared clays （AIZr-PILC） via ion exchange. Compared with conventional methods, our method successfully shortened synthetic routes and greatly reduced consumption of the materials. Then, A1Zr-PILC-supported manganese and cerium oxide catalysts were obtained by impregnation method. The compositions and properties of these catalysts were characterized by some technical means. The energy dispersive X-ray spectroscopy clearly shows the existence of Mn, Ce, and O, which indicates the successful loading of the active components on the surface of AIZr-PILC. Meanwhile, the results of X- ray diffraction （XRD） and N2 adsorption experiments demonstrate that the synthesized A1Zr-PILC out- performs the raw clays （Na-mmt） and mononuclear AI-PILC in the catalytic combustion of chloroben- zene. XRD and high-resolution transmission electron microscopy also proves that the high activity of them is related to the high dispersion of the oxides and the exposure of more active sites. H2-temper- ature-programmed reduction shows that cerium can promote the redox cycles of the manganese system through the strong interactions between MnO2, CeO2 and AIZr-PILC. In particular, MnCe（9：1 ）/AIZr-PILC shows the best catalytic activity in the catalytic combustion of chlorobenzene.
文摘The electronic conductivity and durability of porous carbon supports can be improved by increasing the degree of graphitization in the material;however,the preparation of highly graphitic porous carbon using conventional furnaces remains a significant challenge.Herein,we demonstrate a universal and highly efficient carbothermal shock strategy that significantly improves the degree of graphitization of porous carbon supports,including bowl‐like carbon,hollow carbon spheres,ZIF8‐derived carbon,BP2000,and Ketjen EC 300J.Taking bowl‐like carbon as an example,we illustrate the synthesis of a graphitized bowl‐like carbon(G‐BC‐S)support and evaluate the performance of PtCo/G‐BC‐S in the oxygen reduction reaction(ORR)in rotating disk electrodes(RDE)and H_(2)/air PEM single cells.PtCo/G‐BC‐S exhibits faster ORR kinetics than PtCo/BC and Pt/C,with little loss of activity(25%)and only 13 mV of E1/2 decay after 20000 cycles accelerated stress testing under 1.0-1.5 V vs.a reversible hydrogen electrode(RHE).The significantly enhanced performance of the PtCo/G‐BC‐S catalyst arises from the high activity and chemical/structural stability of the PtCo intermetallic nanoparticles and from the high degree of graphitization and well‐defined porous structure of the bowl‐like carbon support,which confers excellent electrical conductivity and oxygen transport properties.This study provides a reliable and universal strategy for the development of high‐performance porous carbon supports for practical applications in fuel cells.
基金supported by the National Natural Science Foundation of China(No.62372330).
文摘Workload prediction is critical in enabling proactive resource management of cloud applications.Accurate workload prediction is valuable for cloud users and providers as it can effectively guide many practices,such as performance assurance,cost reduction,and energy consumption optimization.However,cloud workload prediction is highly challenging due to the complexity and dynamics of workloads,and various solutions have been proposed to enhance the prediction behavior.This paper aims to provide an in-depth understanding and categorization of existing solutions through extensive literature reviews.Unlike existing surveys,for the first time,we comprehensively sort out and analyze the development landscape of workload prediction from a new perspective,i.e.,application-oriented rather than prediction methodologies per se.Specifically,we first introduce the basic features of workload prediction,and then analyze and categorize existing efforts based on two significant characteristics of cloud applications:variability and heterogeneity.Furthermore,we also investigate how workload prediction is applied to resource management.Finally,open research opportunities in workload prediction are highlighted to foster further advancements.
基金We thank the financial supports from the National Natural Science Foundation of China(No.21576243)the Natural Science Foundation of Zhejiang Province(Nos.LY18B060006,LY17B060001,and LY21B030003).
文摘Enhancing the selectivity of noble metal catalysts through electronic modulation is important for academic research and chemical industrial processes.Herein,we report a facile sacrificial template strategy for the synthesis of PdZn intermetallic compound(3-4 nm)highly distributed in ZnO/nitrogen-decorated carbon hollow spheres(PdZn-ZnO/NCHS)to optimize the selectivity of Pd catalysts,which involves carbonization of a core-shell structured polystyrene(PS)@ZIF-8 precursor in an inert atmosphere,impregnation Pd precursor,and subsequent H2 reduction treatment.Due to the unique structural and compositional features,the developed PdZn-ZnO/NCHS delivers an excellent catalytic performance for the semihydrogenation of 2-methyl-3-butyn-2-ol(MBY)to 2-methyl-3-buten-2-ol(MBE)with high activity(>99%),high selectivity(96%),and good recyclability,outperforming the analog Pd on ZnO(Pd/ZnO)as well as the supported Pd nanoparticles(Pd/C and Pd/NC).Density functional theory(DFT)calculations reveal that the presence of Znδ+species in PdZn-ZnO/NCHS alters the adsorption modes of reactant and product,leading to a decrease of the adsorption strength and an enhancement of the energy barrier for overhydrogenation,which results in a kinetic favor for the selective transformation of MBY to MBE.In addition,PdZn-ZnO/NCHS was also very effective for the partial hydrogenation of dehydrolinalool to hydrolinalool.
基金the National Natural Science Foundation of China(Nos.21576243 and 21701168)Natural Science Foundation of Zhejiang Province(Nos.LY18B060006,LY17B060001,and LY21B030003)+2 种基金the National Key R&D Program of China(No.2020YFA0406101)Dalian high level talent innovation project(No.2019RQ063)Open project Foundation of State Key Laboratory of Structural Chemistry,Fujian Institute of Research on the Structure of Matter,Chinese Academy of Sciences(No.20200021).
文摘Designing and synthesizing high-efficiency non-precious metal-based catalysts having uniform active sites increases the reactivity and selectivity of materials and provides a platform for an in-depth understanding of their catalytic reaction mechanism.In this study,we provided an approach for fabricating isolated nickel single-atom sites(Ni SAs)with high loading(4.9 wt.%)stabilized on nitrogen-doped hollow carbon spheres(NHCS)using a core–shell structured Zn/Ni bimetallic zeolitic imidazolate framework(ZIF)composite as the sacrificial template.The as-fabricated Ni SAs/NHCS catalyst shows superior activity,selectivity,and recycling durability for the catalytic transfer hydrogenation of nitrobenzene to aniline,thus achieving 100%yield of aniline with a turn-over frequency(TOF)value as high as 29.9 h^(−1) under mild conditions.This TOF value is considerably superior to the supported Ni nanoparticle catalysts.The experiments designed show that the hollow structure feature of NHCS facilitates accessible active sites and mass transfer,which thus contributes to the enhancement of the catalytic performance of Ni SAs/NHCS.Density functional theory calculations show the high chemo-selectivity and activity of the Ni SAs catalyst,arising from the unique role of the single Ni-N3 site on simultaneously activating the H donor(N_(2)H_(4))and substrate,as well as the hydrogenation of the–NOH group as the rate-determining step.
