This article examines the pathway to digital transformation and upgrading in undergraduate institutions,using the civil engineering program at Chongqing Three Gorges University as a case study,focusing on six key area...This article examines the pathway to digital transformation and upgrading in undergraduate institutions,using the civil engineering program at Chongqing Three Gorges University as a case study,focusing on six key areas:developing a high-quality digital talent training program for civil engineering;assembling diverse resources to create a digital,multi-scenario open learning environment that encompasses teaching,research,and practical training for civil engineering undergraduates;piloting innovative digital teaching models for civil engineering undergraduates;crafting a new model for digital resource provision,utilizing self-developed and specialized resources;devising assessment methods and ongoing improvement strategies based on the achievement of students’digital competencies;and devising a new,three-dimensional,multi-modal teaching evaluation system through intelligent data capture and analysis.展开更多
In order to reveal which role the callose played in R. rugosa pollination incompatibility, the full-length cDNA sequence of β-1,3-glucanase gene was cloned for the first time from the stylus of Rosa rugosa “Tanghong...In order to reveal which role the callose played in R. rugosa pollination incompatibility, the full-length cDNA sequence of β-1,3-glucanase gene was cloned for the first time from the stylus of Rosa rugosa “Tanghong” with RT-PCR and RACE methods and named as RrGlu. The full-length cDNA is 1380 bp with an open reading frame of 1041 bp, encoding 346 amino acids. The derived protein has a molecular weight of 37.85 kD, a calculated pI of 9.12, a pfam00332 conserved domain at position 36 - 345, and belongs to glycosyl hydrolase family 17. The derived protein is a hydrophilic protein secreted into the vacuole. There is a signal peptide cleavage site at position 34 - 35, a transmembrane domain at position 13 - 32, six Ser phosphorylation sites, three Thr phosphorylation sites, three Tyr phosphorylation sites, one N-glycosylation site, and five O-glycosylation sites. There are 31.50% α-helixes, 30.92% random coil, 25.14% extended peptide chain, and 12.43% β-corner structure. This protein and the Glu protein from eight other species, including Prunus persica, share a sequence homology of greater than 72%;all of the proteins contain a pfam00332 conserved domain and a β-1,3-glucanase active center sequence (LIVM)-X-(LIVMFYW)3-(STAG)-E-(ST)-G-W-P-(ST)-X-G. Furthermore, their phylogenetic relationships are consistent with their traditional classifications. These results were meaningful to reveal the molecular mechanism of R. rugosa pollination incompatibility and improve the theory and techniques of breeding ornamental R. rugosa.展开更多
In order to lay a foundation for researching the function of Rosa rugose (R. rugosa) RrGlu gene, the RrGlu gene was amplified from the styles of R. rugosa “Tanghong”, a gene expression vector named PBI121-RrGlu was ...In order to lay a foundation for researching the function of Rosa rugose (R. rugosa) RrGlu gene, the RrGlu gene was amplified from the styles of R. rugosa “Tanghong”, a gene expression vector named PBI121-RrGlu was constructed and the vector was introduced into tobacco with the agrobacterium-mediated method. PCR results showed that the RrGlu gene was integrated into the tobacco genome.展开更多
Sentrin-specific protease 3(SENP3), a member of the desumoylating enzyme family, is known as a redox sensor and could regulate multiple cellular signaling pathways. However, its implication in myocardial ischemia re...Sentrin-specific protease 3(SENP3), a member of the desumoylating enzyme family, is known as a redox sensor and could regulate multiple cellular signaling pathways. However, its implication in myocardial ischemia reperfusion(MIR) injury is unclear. Here, we observed that SENP3 was expressed and upregulated in the mouse heart depending on reactive oxygen species(ROS) production in response to MIR injury. By utilizing si RNA-mediated cardiac specific gene silencing, SENP3 knockdown was demonstrated to significantly reduce MIR-induced infarct size and improve cardiac function. Mechanistic studies indicated that SENP3 silencing ameliorated myocardial apoptosis mainly via suppression of endoplasmic reticulum(ER) stress and mitochondrial-mediated apoptosis pathways. By contrast, adenovirusmediated cardiac SENP3 overexpression significantly exaggerated MIR injury. Further molecular analysis revealed that SENP3 promoted mitochondrial translocation of dynamin-related protein 1(Drp1) in reperfused myocardium. In addition, mitochondrial division inhibitor-1(Mdivi-1), a pharmacological inhibitor of Drp1, significantly attenuated the exaggerated mitochondrial abnormality and cardiac injury by SENP3 overexpression after MIR injury. Taken together, we provide the first direct evidence that SENP3 upregulation pivotally contributes to MIR injury in a Drp1-dependent manner, and suggest that SENP3 suppression may hold therapeutic promise for constraining MIR injury.展开更多
The number of genetically modified mouse models that mimic human disease is growing rapidly,but only a tiny fraction has been commonly used.According to The Knockout Mouse Program(Lloyd,2011),a public resource of mous...The number of genetically modified mouse models that mimic human disease is growing rapidly,but only a tiny fraction has been commonly used.According to The Knockout Mouse Program(Lloyd,2011),a public resource of mouse embryonic stem cells containing a null mutation in every gene in the mouse genome,8,916 mutant mice lines were phenotyped up to 19 July 2022.Due to the poor correlation between the genomic responses in the mouse models and those responses in human disease,and since humans differ significantly in their genetic vulnerability to common diseases,we still need better mouse models,especially for common and chronic human diseases,including cancer,pulmonary and cardiovascular diseases,obesity and diabetes,behavioral disorders,and neurodegenerative diseases.These new models will be placed into a public repository,The China National Human Disease Animal Model Resource Center(NAMR).This project is funded by Ministry of Science and Technology of China and specializes in the creation,introduction,collection,preservation,and supply of animal model resources forhuman diseases.展开更多
Exosome, which is a kind of extracellular vesicles with size around 40-160 nm, plays an important role in cell-to-cell communication in multiple diseases. Especially in tumor microenvironment, exosomes are the importa...Exosome, which is a kind of extracellular vesicles with size around 40-160 nm, plays an important role in cell-to-cell communication in multiple diseases. Especially in tumor microenvironment, exosomes are the important pathway to transit proteins, nucleic acids and small molecules between different kinds of cells. Based on these characteristics, exosomes are served as both therapeutic agents and drug delivery systems in cancer therapy. In this review, the applications of exosomes as drug delivery systems in cancer therapy were summarized and classified according to the cell source of the exosomes, including normal cells, immune cells and tumor cells. Different modifications of exosomes and drug loading methods were presented. Finally, some challenges that hindered the clinical translation of exosomes were also discussed.展开更多
The effect of cooling rate on the transition of dendrite morphology of a Mg-6Gd (wt%) alloy was semiquantitatively analyzed under a constant temperature gradient by using synchrotron X-ray radiographic technique. Re...The effect of cooling rate on the transition of dendrite morphology of a Mg-6Gd (wt%) alloy was semiquantitatively analyzed under a constant temperature gradient by using synchrotron X-ray radiographic technique. Results show that equiaxed dendrites, including exotic 'butterfly-shaped' dendrite morphology, dominate at high cooling rate (〉1 K/s). When the cooling rate decreases in the range of 0.5-1 K/s, the equiaxed-to-columnar transition takes place, and solute segregates at the center of two long dendrite arms (LDA) of the 'butterfly-shaped' dendrite. When the cooling rate is lower than 0.3 K/s, directional solidification occurs and the columnar dendritic growth direction gradually rotates from the crystalline axis to the thermal gradient direction with an increase in cooling rate. Meanwhile, interface moves faster but the dendrite arm spacing decreases. Floating, collision and rotation of dendrites under convection were also studied in this work.2018 Published by Elsevier Ltd on behalf of The editorial office of Journal of Materials Science & Technology.展开更多
In situ synchrotron X-ray radiography was used to study the effect of direct current(DC) on the grain nucleation and growth of Sn-50 wt.%Pb alloy. The results showed that applying DC adequately during solidification...In situ synchrotron X-ray radiography was used to study the effect of direct current(DC) on the grain nucleation and growth of Sn-50 wt.%Pb alloy. The results showed that applying DC adequately during solidification could effectively enhance the grain nucleation and inhibit its growth. Imaging of comparative experiments with varying DC intensity indicated that the final grain size, determined by the competition between grain nucleation and growth, was sensitively dependent on the DC intensity. It was found that the average grain size was decreased from 1632 to 567 μm with DC density of 1.5 A/mm^2 compared to the case without DC. Beyond this value, raising the current density may cause a significant decrease in the nucleation rate, and thus lead to a coarsening of the grain structure.展开更多
The effect of the high magnetic field(MF)on the distribution of solute concentration during directional solidification of Al-Cu alloy under low growth speed was experimentally investigated.The amount of nonequilibrium...The effect of the high magnetic field(MF)on the distribution of solute concentration during directional solidification of Al-Cu alloy under low growth speed was experimentally investigated.The amount of nonequilibrium eutectic is quantified via X-ray computed tomography(XCT)and demonstrated to reduce with the application of MF.Further,experimental results reveal that the MF alleviates the microsegregation and increases the average Cu concentration in solid solution,leading to the increases of the effective partition coefficient ke.It was also found that Cu concentration in solid solution increases continuously with the increasing intensity of MF,following the strengthening of micro-hardness.The change of ke under the MF is demonstrated to attribute to the thermoelectric magnetic convection(TEMC)in the mushy zone and the thermoelectric magnetic force(TEMF)acting on the solid.The TEMC is supposed to cause secondary convection owing to the inequality in flow velocities of circulation in different positions of dendrite stem.And the vacancies created by the proliferation and movement of dislocations induced by TEMF in the matrix is supposed to be able to capture solute atoms and thus enhance the solute concentration in the solid solution.展开更多
Mg_(3)Sb_(2)-based thermoelectric materials have poor electrical conductivity which is the key to limit thermoelectric performance that need to be solved.Herein we tuned the carrier concentration of Mg_(3)Sb_(2)-based...Mg_(3)Sb_(2)-based thermoelectric materials have poor electrical conductivity which is the key to limit thermoelectric performance that need to be solved.Herein we tuned the carrier concentration of Mg_(3)Sb_(2)-based materials via Ag doping at the Mg sites(at two distinct crystallographic sites)to enhance the electrical performance.Mg_(3-x)Ag_(x)Sb_(2)(0≤x≤0.05)has been prepared successfully by vacuum suspension smelting plus Spark Plasma Sintering technique.Using the vacuum suspension smelting plus Spark Plasma Sintering method,we proved that Ag doping can precisely tune the electrical transport properties and accordingly enhance the power factor.Moreover,the Ag doping leads to a low lattice thermal conductivity due to phonons scattering,and the maximal thermoelectric figure of merit ZT for Mg_(3-x)Ag_(x)Sb_(2)reaches 0.66 at 773 K.展开更多
Plate-like Fe-rich intermetallic phases directly influence the mechanical properties of recycled Al alloys;thus, many attempts have been made to modify the morphology of these phases. Through synchrotron X-ray imaging...Plate-like Fe-rich intermetallic phases directly influence the mechanical properties of recycled Al alloys;thus, many attempts have been made to modify the morphology of these phases. Through synchrotron X-ray imaging and electron microscopy, the underlying nucleation and growth mechanisms of Fe-rich phases during the solidification of Al-5 Ti-1 B-modified Al-2 Fe alloys were revealed in this study. The results showed that the Al-5 Ti-1 B grain refiner as well as the applied pressure both resulted in reduction of the size and number of primary Al_(3)Fe phases and promoted the formation of eutectic Al_(6)Fe phases.The tomography results demonstrated that Al-5 Ti-1 B changed the three-dimensional(3 D) morphology of primary Fe-rich phases from rod-like to branched plate-like, while a reduction in their thickness and size was also observed. This was attributed to the fact that Ti-containing solutes in the melts inhibit the diffusion of Fe atoms and the Al_(3)Fe twins produce re-entrant corner on the twin boundaries along the growth direction. Moreover, the TiB_(2) provides possible nucleation sites for Al_6Fe phases. The nucleation mechanism of Fe-rich phases is discussed in terms of experimental observations and crystallography calculations. The decrease in the lattice mismatch between TiB_(2) and Al_(6)Fe phases was suggested, which promoted the transformation of Al_(3)Fe to Al_(6)Fe phases.展开更多
Controlling both amplitude and phase of light in the subwavelength scale is a challenge for traditional optical devices.Here,we propose and numerically investigate a novel plasmonic meta-hologram,demonstrating broadba...Controlling both amplitude and phase of light in the subwavelength scale is a challenge for traditional optical devices.Here,we propose and numerically investigate a novel plasmonic meta-hologram,demonstrating broadband manipulation of both phase and amplitude in the subwavelength scale.In the meta-hologram,phase modulation is achieved by the detour phase distribution of unit cells,and amplitude is continuously modulated by a T-shaped nano-cavity with tunable plasmonic resonance.Compared to phase-only holograms,such a metahologram could reconstruct three-dimensional(3D)images with higher signal-to-noise ratio and better image quality,thus offering great potential in applications such as 3D displays,optical communications,and beam shaping.展开更多
Grain refinement of Al alloys inoculated by rare earth elements,such as Sc,has been extensively acknowledged,while the practical behavior of how inoculant Al_(3)Sc particles affect the refinement in solidification has...Grain refinement of Al alloys inoculated by rare earth elements,such as Sc,has been extensively acknowledged,while the practical behavior of how inoculant Al_(3)Sc particles affect the refinement in solidification has not been clarified due to the non-transparency of the solidification process.Here,the microstructural evolution of primary Al_(3)Sc particles andα-Al grains in Al-10 wt.%Cu alloy solidifications with 0.2 wt.%,0.6 wt.%,and 1.0 wt.%Sc additions was investigated by in situ synchrotron X-ray radiography.The detailed mechanisms of curve motion of grains(CMG)and melt convection were revealed.The efficient grains nucleation,uniformly scattered small initial grains,and long duration of melt convection contributed to the best refinement in the 0.6 wt.%Sc addition sample.This work provides a deep insight into grain refinement in solidification with Sc addition,which will enlighten the composition design and casting process of Al alloys inoculated by rare earth elements.展开更多
The accomplishment of nanowelding typically requires the input of high energy,possibly causing appreciable damages to the brittle nanomaterial.Herein,we report an external field(EF,i.e.,light,direct current(DC),and al...The accomplishment of nanowelding typically requires the input of high energy,possibly causing appreciable damages to the brittle nanomaterial.Herein,we report an external field(EF,i.e.,light,direct current(DC),and alternating current(AC))-strengthened Ostwald nanowelding(ONW)strategy to enable low-temperature nanowelding of Au nanoparticles(NPs)with nanoscale spacing in solution and propose an electron localization mechanism to understand it.We reveal that the EF-derived local electrons not only greatly strengthen the dissolution of surface atoms and the reduction of Au3+ions dissolved,but also confine(together with ordered water molecules)the transport of Au^(3+)ions within the nanogap.Consequently,the electrochemical Ostwald ripening(OR)process of the Au NPs is actively strengthened,which,along with the local electron-strengthened surface atom diffusion(as a result of the strong electrostatic repulsion created),enables feasible ONW for solution processing of interdigital electrodes(IDEs)from Au NPs and high-performance transparent conductor(TC)from Ag nanowires(NWs).Our low-temperature nanowelding strategy offers an efficient interconnection technique for the processing of functional nanodevices from individual nanomaterials.展开更多
In situ synchrotron X-radiography was carried out on Al-13 Cu and Al-13 Cu-7 Si alloys with and without addition of Al-5 Ti-1 B master alloy.The effects of Si content on grain growth and the solute-suppressed nucleati...In situ synchrotron X-radiography was carried out on Al-13 Cu and Al-13 Cu-7 Si alloys with and without addition of Al-5 Ti-1 B master alloy.The effects of Si content on grain growth and the solute-suppressed nucleation zone(SSNZ)were quantitatively studied.The average grain size can be refined to 164μm of Al-13 Cu alloy inoculated by Al-5 Ti-1B.After addition of 7%Si content,a large number of TiB 2 sites in the melt lost the inoculating ability due to"Si poisoning."The radius of the dendrite tip curvature of Al-13 Cu is more than two times as large as that of Al-13 Cu-7 Si.The sharper tip is able to disperse the solute more effectively and thus grains can grow more rapidly.This causes that the dendrite arm growth rate with addition of 7%Si solute is about 2.6 times that of no Si addition.In addition,the solute enrichment in the SSNZ of Al-13 Cu is faster,and the area change of SSNZ is slower than that of Al-13 Cu-7 Si.Thus more nucleation sites in the SSNZ cannot be activated with addition of Si.This study will shed light on the understanding of Si poisoning in casting Al-Cu-Si alloys.展开更多
The cylindrical vector beam(CVB) has been extensively studied in recent years, but detection of CVBs with on-chip photonic devices is a challenge. Here, we propose and theoretically study a chiral plasmonic lens struc...The cylindrical vector beam(CVB) has been extensively studied in recent years, but detection of CVBs with on-chip photonic devices is a challenge. Here, we propose and theoretically study a chiral plasmonic lens structure for CVB detection. The structure illuminated by a CVB can generate single plasmonic focus, whose focal position depends on the incident angle and the polarization order of CVB. Thus, the incident CVB can be detected according to the focal position and incident angle and with a coupling waveguide to avoid the imaging of the whole plasmonic field. It shows great potential in applications including CVB-multiplexing integrated communication systems.展开更多
The optical vortex beam has widely been studied and used because of its unique orbital angular momentum(OAM).To generate and control OAM in compact and integrated systems,many metallic metasurface devices have been pr...The optical vortex beam has widely been studied and used because of its unique orbital angular momentum(OAM).To generate and control OAM in compact and integrated systems,many metallic metasurface devices have been proposed,however,most of them suffer from the low efficiency.Here,we propose and experimentally verify a high-efficiency monolayer metallic metasurface composed of semicircular nano-grooves distributed with detour phase.The metasurface can generate single or an array of OAM with spin-sensitive modulation and achieve the maximum efficiency of 60.2%in theory and 30.44%in experiment.This work has great potential in compact OAM detection and communication systems.展开更多
基金Chongqing Higher Education Teaching Reform Research Key Project(Project number:222128)Chongqing Three Gorges University Higher Education Research Project(Project number:JGSZH2203)+3 种基金Chongqing Education Science Planning Project(Project number:K23ZG2120245,K22ZS212737,K23YD2120100)Chongqing Three Gorges University First-Class Undergraduate Course“Principles of Steel Structures”Chongqing Three Gorges University Course Ideological and Political Demonstration Course“Principles of Steel Structures”Chongqing First-Class Undergraduate Course“Principles of Steel Structures”。
文摘This article examines the pathway to digital transformation and upgrading in undergraduate institutions,using the civil engineering program at Chongqing Three Gorges University as a case study,focusing on six key areas:developing a high-quality digital talent training program for civil engineering;assembling diverse resources to create a digital,multi-scenario open learning environment that encompasses teaching,research,and practical training for civil engineering undergraduates;piloting innovative digital teaching models for civil engineering undergraduates;crafting a new model for digital resource provision,utilizing self-developed and specialized resources;devising assessment methods and ongoing improvement strategies based on the achievement of students’digital competencies;and devising a new,three-dimensional,multi-modal teaching evaluation system through intelligent data capture and analysis.
文摘In order to reveal which role the callose played in R. rugosa pollination incompatibility, the full-length cDNA sequence of β-1,3-glucanase gene was cloned for the first time from the stylus of Rosa rugosa “Tanghong” with RT-PCR and RACE methods and named as RrGlu. The full-length cDNA is 1380 bp with an open reading frame of 1041 bp, encoding 346 amino acids. The derived protein has a molecular weight of 37.85 kD, a calculated pI of 9.12, a pfam00332 conserved domain at position 36 - 345, and belongs to glycosyl hydrolase family 17. The derived protein is a hydrophilic protein secreted into the vacuole. There is a signal peptide cleavage site at position 34 - 35, a transmembrane domain at position 13 - 32, six Ser phosphorylation sites, three Thr phosphorylation sites, three Tyr phosphorylation sites, one N-glycosylation site, and five O-glycosylation sites. There are 31.50% α-helixes, 30.92% random coil, 25.14% extended peptide chain, and 12.43% β-corner structure. This protein and the Glu protein from eight other species, including Prunus persica, share a sequence homology of greater than 72%;all of the proteins contain a pfam00332 conserved domain and a β-1,3-glucanase active center sequence (LIVM)-X-(LIVMFYW)3-(STAG)-E-(ST)-G-W-P-(ST)-X-G. Furthermore, their phylogenetic relationships are consistent with their traditional classifications. These results were meaningful to reveal the molecular mechanism of R. rugosa pollination incompatibility and improve the theory and techniques of breeding ornamental R. rugosa.
文摘In order to lay a foundation for researching the function of Rosa rugose (R. rugosa) RrGlu gene, the RrGlu gene was amplified from the styles of R. rugosa “Tanghong”, a gene expression vector named PBI121-RrGlu was constructed and the vector was introduced into tobacco with the agrobacterium-mediated method. PCR results showed that the RrGlu gene was integrated into the tobacco genome.
基金supported by the National Science Fund for Distinguished Young Scholars(No.81625002)the National Natural Science Foundation of China(Nos.81470389,81270282,81330006,81500200,81500221,81070176,81170192,81400261,81600268,and 81601238)+5 种基金the Program of Shanghai Academic Research Leader(18XD1402400)the Shanghai Municipal Education Commission Gaofeng Clinical Medicine Grant Support(No.20152209)Shanghai Shenkang Hospital Development Center(16CR3034A)Shanghai Jiao Tong University(YG2013MS42 and YG2015MS54)Shanghai Jiao Tong University School of Medicine(15ZH1003 and 14XJ10019)the Shanghai Sailing Program(18YF1413000)
文摘Sentrin-specific protease 3(SENP3), a member of the desumoylating enzyme family, is known as a redox sensor and could regulate multiple cellular signaling pathways. However, its implication in myocardial ischemia reperfusion(MIR) injury is unclear. Here, we observed that SENP3 was expressed and upregulated in the mouse heart depending on reactive oxygen species(ROS) production in response to MIR injury. By utilizing si RNA-mediated cardiac specific gene silencing, SENP3 knockdown was demonstrated to significantly reduce MIR-induced infarct size and improve cardiac function. Mechanistic studies indicated that SENP3 silencing ameliorated myocardial apoptosis mainly via suppression of endoplasmic reticulum(ER) stress and mitochondrial-mediated apoptosis pathways. By contrast, adenovirusmediated cardiac SENP3 overexpression significantly exaggerated MIR injury. Further molecular analysis revealed that SENP3 promoted mitochondrial translocation of dynamin-related protein 1(Drp1) in reperfused myocardium. In addition, mitochondrial division inhibitor-1(Mdivi-1), a pharmacological inhibitor of Drp1, significantly attenuated the exaggerated mitochondrial abnormality and cardiac injury by SENP3 overexpression after MIR injury. Taken together, we provide the first direct evidence that SENP3 upregulation pivotally contributes to MIR injury in a Drp1-dependent manner, and suggest that SENP3 suppression may hold therapeutic promise for constraining MIR injury.
基金supported by grants from CAMS initiative for Innovative Medicine of China(No.2021-I2M-1-034)National Key R&D Program of China(No.2021YFF0703200)National Natural Science Foundation of China(No.82041008 and 82161138027).
文摘The number of genetically modified mouse models that mimic human disease is growing rapidly,but only a tiny fraction has been commonly used.According to The Knockout Mouse Program(Lloyd,2011),a public resource of mouse embryonic stem cells containing a null mutation in every gene in the mouse genome,8,916 mutant mice lines were phenotyped up to 19 July 2022.Due to the poor correlation between the genomic responses in the mouse models and those responses in human disease,and since humans differ significantly in their genetic vulnerability to common diseases,we still need better mouse models,especially for common and chronic human diseases,including cancer,pulmonary and cardiovascular diseases,obesity and diabetes,behavioral disorders,and neurodegenerative diseases.These new models will be placed into a public repository,The China National Human Disease Animal Model Resource Center(NAMR).This project is funded by Ministry of Science and Technology of China and specializes in the creation,introduction,collection,preservation,and supply of animal model resources forhuman diseases.
基金the support of this research by National Natural Science Foundation of China (Nos. 81971737, 32171313)Guangdong Basic and Applied Basic Research Foundation (No. 2020B1515020017)+1 种基金Shenzhen Science and Technology Program (No. RCYX2021070609210433)Guangdong Special Support Program (No. 2019TQ05Y224)。
文摘Exosome, which is a kind of extracellular vesicles with size around 40-160 nm, plays an important role in cell-to-cell communication in multiple diseases. Especially in tumor microenvironment, exosomes are the important pathway to transit proteins, nucleic acids and small molecules between different kinds of cells. Based on these characteristics, exosomes are served as both therapeutic agents and drug delivery systems in cancer therapy. In this review, the applications of exosomes as drug delivery systems in cancer therapy were summarized and classified according to the cell source of the exosomes, including normal cells, immune cells and tumor cells. Different modifications of exosomes and drug loading methods were presented. Finally, some challenges that hindered the clinical translation of exosomes were also discussed.
基金financially supported by the Program of Shanghai Subject Chief Engineering (No. 14XD1425000)the National Natural Science Foundation of China (No. 51304135)the Chinese Scholarship Council and DOE (No. DE-FG02-07ER46417)
文摘The effect of cooling rate on the transition of dendrite morphology of a Mg-6Gd (wt%) alloy was semiquantitatively analyzed under a constant temperature gradient by using synchrotron X-ray radiographic technique. Results show that equiaxed dendrites, including exotic 'butterfly-shaped' dendrite morphology, dominate at high cooling rate (〉1 K/s). When the cooling rate decreases in the range of 0.5-1 K/s, the equiaxed-to-columnar transition takes place, and solute segregates at the center of two long dendrite arms (LDA) of the 'butterfly-shaped' dendrite. When the cooling rate is lower than 0.3 K/s, directional solidification occurs and the columnar dendritic growth direction gradually rotates from the crystalline axis to the thermal gradient direction with an increase in cooling rate. Meanwhile, interface moves faster but the dendrite arm spacing decreases. Floating, collision and rotation of dendrites under convection were also studied in this work.2018 Published by Elsevier Ltd on behalf of The editorial office of Journal of Materials Science & Technology.
基金supported by the National Key Research and Development Program of China (No. 2016YFB0701203)the National Natural Science Foundation of China (Nos. 51525401, 51690163, 51601028, 51401044)Dalian Support Plan for Innovation of High-level Talents (Top and Leading Talents, 2015R013)
文摘In situ synchrotron X-ray radiography was used to study the effect of direct current(DC) on the grain nucleation and growth of Sn-50 wt.%Pb alloy. The results showed that applying DC adequately during solidification could effectively enhance the grain nucleation and inhibit its growth. Imaging of comparative experiments with varying DC intensity indicated that the final grain size, determined by the competition between grain nucleation and growth, was sensitively dependent on the DC intensity. It was found that the average grain size was decreased from 1632 to 567 μm with DC density of 1.5 A/mm^2 compared to the case without DC. Beyond this value, raising the current density may cause a significant decrease in the nucleation rate, and thus lead to a coarsening of the grain structure.
基金supported by National Natural Science Foundation of China(No.51701112 and No.51690162)Shanghai RisingStar Program(20QA1403800)+1 种基金Shanghai Science and Technology Committee(No.17JC1400602 and 19DZ1100704)the support from Shanghai Synchrotron X-ray Facility(SSRF)on experiment and data analysis。
文摘The effect of the high magnetic field(MF)on the distribution of solute concentration during directional solidification of Al-Cu alloy under low growth speed was experimentally investigated.The amount of nonequilibrium eutectic is quantified via X-ray computed tomography(XCT)and demonstrated to reduce with the application of MF.Further,experimental results reveal that the MF alleviates the microsegregation and increases the average Cu concentration in solid solution,leading to the increases of the effective partition coefficient ke.It was also found that Cu concentration in solid solution increases continuously with the increasing intensity of MF,following the strengthening of micro-hardness.The change of ke under the MF is demonstrated to attribute to the thermoelectric magnetic convection(TEMC)in the mushy zone and the thermoelectric magnetic force(TEMF)acting on the solid.The TEMC is supposed to cause secondary convection owing to the inequality in flow velocities of circulation in different positions of dendrite stem.And the vacancies created by the proliferation and movement of dislocations induced by TEMF in the matrix is supposed to be able to capture solute atoms and thus enhance the solute concentration in the solid solution.
基金This work is supported by National Natural Science Foundation of China(Grant No.51371010,51572066,50801002)the Beijing Municipal Natural Science Foundation(Grant No.2112007).
文摘Mg_(3)Sb_(2)-based thermoelectric materials have poor electrical conductivity which is the key to limit thermoelectric performance that need to be solved.Herein we tuned the carrier concentration of Mg_(3)Sb_(2)-based materials via Ag doping at the Mg sites(at two distinct crystallographic sites)to enhance the electrical performance.Mg_(3-x)Ag_(x)Sb_(2)(0≤x≤0.05)has been prepared successfully by vacuum suspension smelting plus Spark Plasma Sintering technique.Using the vacuum suspension smelting plus Spark Plasma Sintering method,we proved that Ag doping can precisely tune the electrical transport properties and accordingly enhance the power factor.Moreover,the Ag doping leads to a low lattice thermal conductivity due to phonons scattering,and the maximal thermoelectric figure of merit ZT for Mg_(3-x)Ag_(x)Sb_(2)reaches 0.66 at 773 K.
基金supported by the Team Project Natural Science Foundation of Guangdong Province(2015A030312003)Basic and Applied Basic Foundation of Guangdong Province(2019A1515110270)+2 种基金Research start-up funds of DGUT(GC300501138)Scientific Research Foundation of Advanced Talents(Innovation Team)DGUT(No.KCYCXPT2016004 and No.TDQN2019005)Natural Science Foundation of China(52074131)。
文摘Plate-like Fe-rich intermetallic phases directly influence the mechanical properties of recycled Al alloys;thus, many attempts have been made to modify the morphology of these phases. Through synchrotron X-ray imaging and electron microscopy, the underlying nucleation and growth mechanisms of Fe-rich phases during the solidification of Al-5 Ti-1 B-modified Al-2 Fe alloys were revealed in this study. The results showed that the Al-5 Ti-1 B grain refiner as well as the applied pressure both resulted in reduction of the size and number of primary Al_(3)Fe phases and promoted the formation of eutectic Al_(6)Fe phases.The tomography results demonstrated that Al-5 Ti-1 B changed the three-dimensional(3 D) morphology of primary Fe-rich phases from rod-like to branched plate-like, while a reduction in their thickness and size was also observed. This was attributed to the fact that Ti-containing solutes in the melts inhibit the diffusion of Fe atoms and the Al_(3)Fe twins produce re-entrant corner on the twin boundaries along the growth direction. Moreover, the TiB_(2) provides possible nucleation sites for Al_6Fe phases. The nucleation mechanism of Fe-rich phases is discussed in terms of experimental observations and crystallography calculations. The decrease in the lattice mismatch between TiB_(2) and Al_(6)Fe phases was suggested, which promoted the transformation of Al_(3)Fe to Al_(6)Fe phases.
基金supported by the National Natural Science Foundation of China(Nos.61427819,91750205,61490712,U1701661,and 61605117)the National Key Basic Research Program of China(973)(No.2015CB352004)+2 种基金the Leading Talents of Guangdong Province Program(No.00201505)the Natural Science Foundation of Guangdong Province(Nos.2016A030312010,2016A030310063,and 2017A030313351)the Science and Technology Innovation Commission of Shenzhen(Nos.KQTD2017033011044403,ZDSYS201703031605029,and JCYJ2017818144338999)
文摘Controlling both amplitude and phase of light in the subwavelength scale is a challenge for traditional optical devices.Here,we propose and numerically investigate a novel plasmonic meta-hologram,demonstrating broadband manipulation of both phase and amplitude in the subwavelength scale.In the meta-hologram,phase modulation is achieved by the detour phase distribution of unit cells,and amplitude is continuously modulated by a T-shaped nano-cavity with tunable plasmonic resonance.Compared to phase-only holograms,such a metahologram could reconstruct three-dimensional(3D)images with higher signal-to-noise ratio and better image quality,thus offering great potential in applications such as 3D displays,optical communications,and beam shaping.
基金supported by the National Natural Science Foundation of China(Nos.51627802,51871152 and 51971237)the Shanghai Pujiang Program(No.21PJD030)the National Key Research and Development Program of China(No.2020YFB0311200)。
文摘Grain refinement of Al alloys inoculated by rare earth elements,such as Sc,has been extensively acknowledged,while the practical behavior of how inoculant Al_(3)Sc particles affect the refinement in solidification has not been clarified due to the non-transparency of the solidification process.Here,the microstructural evolution of primary Al_(3)Sc particles andα-Al grains in Al-10 wt.%Cu alloy solidifications with 0.2 wt.%,0.6 wt.%,and 1.0 wt.%Sc additions was investigated by in situ synchrotron X-ray radiography.The detailed mechanisms of curve motion of grains(CMG)and melt convection were revealed.The efficient grains nucleation,uniformly scattered small initial grains,and long duration of melt convection contributed to the best refinement in the 0.6 wt.%Sc addition sample.This work provides a deep insight into grain refinement in solidification with Sc addition,which will enlighten the composition design and casting process of Al alloys inoculated by rare earth elements.
基金This work was financially supported by the National Natural Science Foundation of China(Nos.21872047,21673070,and 91750205)lHunan Key Laboratory of Two-Dimensional Materials(No.2018TP1010).
文摘The accomplishment of nanowelding typically requires the input of high energy,possibly causing appreciable damages to the brittle nanomaterial.Herein,we report an external field(EF,i.e.,light,direct current(DC),and alternating current(AC))-strengthened Ostwald nanowelding(ONW)strategy to enable low-temperature nanowelding of Au nanoparticles(NPs)with nanoscale spacing in solution and propose an electron localization mechanism to understand it.We reveal that the EF-derived local electrons not only greatly strengthen the dissolution of surface atoms and the reduction of Au3+ions dissolved,but also confine(together with ordered water molecules)the transport of Au^(3+)ions within the nanogap.Consequently,the electrochemical Ostwald ripening(OR)process of the Au NPs is actively strengthened,which,along with the local electron-strengthened surface atom diffusion(as a result of the strong electrostatic repulsion created),enables feasible ONW for solution processing of interdigital electrodes(IDEs)from Au NPs and high-performance transparent conductor(TC)from Ag nanowires(NWs).Our low-temperature nanowelding strategy offers an efficient interconnection technique for the processing of functional nanodevices from individual nanomaterials.
基金supported by the GDAS’Project of Science and Technology Development(No.2020GDASYL-20200103140)the Fundamental and Applied Fundamental Research Foundation of Guangdong Province(No.2020B1515120065)the National Natural Science Foundation of China(No.U1832183)。
文摘In situ synchrotron X-radiography was carried out on Al-13 Cu and Al-13 Cu-7 Si alloys with and without addition of Al-5 Ti-1 B master alloy.The effects of Si content on grain growth and the solute-suppressed nucleation zone(SSNZ)were quantitatively studied.The average grain size can be refined to 164μm of Al-13 Cu alloy inoculated by Al-5 Ti-1B.After addition of 7%Si content,a large number of TiB 2 sites in the melt lost the inoculating ability due to"Si poisoning."The radius of the dendrite tip curvature of Al-13 Cu is more than two times as large as that of Al-13 Cu-7 Si.The sharper tip is able to disperse the solute more effectively and thus grains can grow more rapidly.This causes that the dendrite arm growth rate with addition of 7%Si solute is about 2.6 times that of no Si addition.In addition,the solute enrichment in the SSNZ of Al-13 Cu is faster,and the area change of SSNZ is slower than that of Al-13 Cu-7 Si.Thus more nucleation sites in the SSNZ cannot be activated with addition of Si.This study will shed light on the understanding of Si poisoning in casting Al-Cu-Si alloys.
基金This work was partially supported by the Guangdong Major Project of Basic and Applied Basic Research(No.2020B0301030009)National Natural Science Foundation of China(Nos.91750205,62175157,U1701661,61935013,61975128,61805165,and 62105219)+2 种基金Leading Talents of Guangdong Province(No.00201505)Natural Science Foundation of Guangdong Province(No.2019TQ05X750)Shenzhen Science and Technology Program(Nos.JCYJ20180507182035270,JCYJ20210324120403011,and KQTD20170330110444030)。
文摘The cylindrical vector beam(CVB) has been extensively studied in recent years, but detection of CVBs with on-chip photonic devices is a challenge. Here, we propose and theoretically study a chiral plasmonic lens structure for CVB detection. The structure illuminated by a CVB can generate single plasmonic focus, whose focal position depends on the incident angle and the polarization order of CVB. Thus, the incident CVB can be detected according to the focal position and incident angle and with a coupling waveguide to avoid the imaging of the whole plasmonic field. It shows great potential in applications including CVB-multiplexing integrated communication systems.
基金supported by the Guangdong Major Project of Basic and Applied Basic Research(No.2020B0301030009)National Natural Science Foundation of China(Nos.62175157,61935013,61975128,and 62105219)+2 种基金Leading Talents of Guangdong Province Program(No.00201505)Natural Science Foundation of Guangdong Province(No.2019TQ05X750)Shenzhen Science and Technology Program(Nos.JCYJ20180507182035270,RCJC20210609103232046,JCYJ20210324120403011,and KQTD20170330110444030)。
文摘The optical vortex beam has widely been studied and used because of its unique orbital angular momentum(OAM).To generate and control OAM in compact and integrated systems,many metallic metasurface devices have been proposed,however,most of them suffer from the low efficiency.Here,we propose and experimentally verify a high-efficiency monolayer metallic metasurface composed of semicircular nano-grooves distributed with detour phase.The metasurface can generate single or an array of OAM with spin-sensitive modulation and achieve the maximum efficiency of 60.2%in theory and 30.44%in experiment.This work has great potential in compact OAM detection and communication systems.