Constructing efficient carbon material with enhanced mass transfer ability from vacuum residuum(VR)is of prime industrial and scientific significance.Herein,we demonstrated a one-pot synthesis of metal-free and highly...Constructing efficient carbon material with enhanced mass transfer ability from vacuum residuum(VR)is of prime industrial and scientific significance.Herein,we demonstrated a one-pot synthesis of metal-free and highly symmetric hollow carbon cubes(HCCs)using cost-efficient vacuum residuum(VR)as a C/N/S source.By multi-techniques such as TEM,SEM,Raman,XPS,and XRD,it is found that the CTAB surfactant plays an important role in emulsifying and forming oil-in-water suspension particles.Subsequently,high aromatics contents in VR favor the formation of HCCs shell by graphitization on the surface of Na Cl template.Notably,heavy metals(e.g.,V,Ni)are not enriched in carbon skeleton due to the unique graphitization mechanism.This metal-free HCCs catalyst showed good catalytic stability and high selectivity towards direct and local electrochemical production of hydrogen peroxide(H_(2)O_(2))through two-electron O_(2)reduction due to enhanced mass transfer ability.The results provide a novel avenue to synthesize metal-free cubic carbon material from low-cost and plentiful VR,which are essential to the design of more efficient catalysts for O_(2)reduction to H_(2)O_(2).展开更多
The development of graphene-based composites with low density,robust absorption,wide bandwidth and thin thickness remained a great challenge in the field of electromagnetic(EM)absorption.In this work,nitrogen-doped re...The development of graphene-based composites with low density,robust absorption,wide bandwidth and thin thickness remained a great challenge in the field of electromagnetic(EM)absorption.In this work,nitrogen-doped reduced graphene oxide/hollow cobalt ferrite(NRGO/hollow CoFe_(2)O_(4))composite aerogels were constructed by a solvothermal and hydrothermal two-step route.Results demonstrated that the as-fabricated composite aerogels had the ultralow density and a unique three-dimensional(3D)network structure,and lots of hollow CoFe_(2)O_(4)microspheres were almost homogeneously distributed on the wrinkled surfaces of lamellar NRGO.Moreover,superior EM absorbing capacity could be achieved by modulating the ferrite structure,addition amounts of hollow CoFe_(2)O_(4)and thicknesses.It was noteworthy that the NRGO/hollow CoFe_(2)O_(4)composite aerogel with the addition amount of ferrite of 15.0 mg pos-sessed the minimum reflection loss of-44.7 dB and maximum absorption bandwidth of 5.2 GHz(from 12.6 to 17.8 GHz)at a very thin thickness of 1.8 mm and filling ratio of 15.0 wt.%.Furthermore,the possible EM attenuation mechanism had been proposed.The results of this work would be helpful for developing RGO-based 3D composites as lightweight,thin and highly efficient EM wave absorbers.展开更多
Background： The accurate measurement of the femoral anteversion （FA） angle is always a topic of much debate in the orthopedic surgery and radiology research. We aimed to explore a new FA measurement method to acqui...Background： The accurate measurement of the femoral anteversion （FA） angle is always a topic of much debate in the orthopedic surgery and radiology research. We aimed to explore a new FA measurement method to acquire accurate results without radiation damage using piglet model. Methods： A total of thirty piglets were assigned to two groups based on the age. Bilateral femora were imaged with 3.0-T magnetic resonance （MR） and 64-slice computed tomography （CT） examinations on all piglets. FA was measured on MR-three-dimensional （3D） postprocessing software with a four-step method： initial validation of the femoral condylar axis, validation of the condylar plane, validation of the femoral neck axis, and line-plane angle measurement of FA. After MR and CT examinations, all piglets were sacrificed and their degree of FA was measured using their excised, dried femora. MR, CT, and dried-femur measurement results were analyzed statistically; M R and CT measurements were compared for accuracy against each other and against the gold standard dried femur measurement. Results： In both groups, the mean FA value measured by MR was lower than that measured by CT. A statistically significant difference was observed between CT- and dried-femur measurements but not between MR- and dried-femur measurements. A higher correlation （0.783 vs. 0.408） and a higher consistency （0.863 vs. 0.578） with dried-femur measurement results were seen for MR measurements than CT measurements in the 1 -week age group. However, in the 8-week age group, similar correlations （0.707 vs. 0.669） and consistencies （0.864 vs. 0.82 l ） were observed. Conclusions： Noninvasive MR-3D-Cube reconstruction was able to accurately measure FA in piglets. Particularly in the 1-week age group with a larger proportion of cartilaginous structures, the correlation and consistency between MR- and dried-femur measurement results were higher than those between CT- and dried-femur measurements, suggesting that MR may be a new useful examination tool for FA-related diseases in children.展开更多
A appropriate size with three-dimension(3 D) channels for lithium diffusion plays an important role in constructing highperforming LiNi_(0.5)Mn_(1.5)O_4(LNMO) cathode materials, as it can not only reduce the transport...A appropriate size with three-dimension(3 D) channels for lithium diffusion plays an important role in constructing highperforming LiNi_(0.5)Mn_(1.5)O_4(LNMO) cathode materials, as it can not only reduce the transport path of lithium ions and electrons, but also reduce the side effects and withstand the structural strain in the process of repetitive Li~+ intercalation/deintercalation. In this work, an e fficient method for designing the hollow LNMO microsphere with 3 D channels structure by using polyethylene oxide(PEO) as soft template agent assisted solvothermal method is proposed. Experimental results indicate that PEO can make the reagents mingle evenly and nucleate slowly in the solvothermal process, thus obtaining a homogeneous distribution of carbonate precursors. In the final LNMO products, the hollow 3 D channels structure obtained by the decomposition of PEO and carbonate precursor in the calcination can provide abundant electroactive zones and electron/ion transport paths during the charge/discharge process, which benefits to improve the cycling performance and rate capability. The LNMO prepared by adding 1 g PEO possesses the most outstanding electrochemical performance, which presented an excellent discharge capacity of 143.1 mAh g~(-1) at 0.1 C and with a capacity retention of 92.2% after 100 cycles at 1 C. The superior performance attributed to the 3 D channels structure of hollow microspheres, which provide uninterrupted conductive systems and therefore achieve the stable transfer for electron/ion.展开更多
Microelectrodes are a type of electrode with microscopic dimension, and due to their rapid diffusing rates, high electrical current densities and signal-to-noise ratios, they can help improve the detection sensitivity...Microelectrodes are a type of electrode with microscopic dimension, and due to their rapid diffusing rates, high electrical current densities and signal-to-noise ratios, they can help improve the detection sensitivity for various analytes [1]. Investigations on the fabrication and the application of microelectrodes are highly relevant. Fiber-type microelectrodes with one-dimensional (ID) microstructures that possess ID diffusion, particularly carbon fiber microelectrodes, have been widely fabricated and used in many different types of sensors due to their low cost, small volume, portability, and good biocompatibility [1,2]. However, poor electrocatalytic activity and low response currents preclude the applications of carbon fiber microelectrodes in sensors.展开更多
Three-dimensional(3D)bioprinting is a rapidly growing technology that has been widely used in tissue engineering,disease studies,and drug screening.It provides the unprecedented capacity of depositing various types of...Three-dimensional(3D)bioprinting is a rapidly growing technology that has been widely used in tissue engineering,disease studies,and drug screening.It provides the unprecedented capacity of depositing various types of biomaterials,cells,and biomolecules in a layer-by-layer fashion,with precisely controlled spatial distribution.This technology is expected to address the organ-shortage issue in the future.In this review,we first introduce three categories of 3D bioprinting strategies:inkjet-based printing(IBP),extrusion-based printing(EBP),and light-based printing(LBP).Biomaterials and cells,which are normally referred to as“bioinks,”are then discussed.We also systematically describe the recent advancements of 3D bioprinting in fabricating cell-laden artificial tissues and organs with solid or hollow structures,including cartilage,bone,skin,muscle,vascular network,and so on.The development of organs-onchips utilizing 3D bioprinting technology for drug discovery and toxicity testing is reviewed as well.Finally,the main challenges in current studies and an outlook of the future research of 3D bioprinting are discussed.展开更多
The development of efficient three-dimensional cell imaging technology is a necessary means to study cell composition and structure,especially to track and monitor the phagocytosis process of nanoparticles by cells.He...The development of efficient three-dimensional cell imaging technology is a necessary means to study cell composition and structure,especially to track and monitor the phagocytosis process of nanoparticles by cells.Herein,we prepared a MoO_(2)hollow nanosphere with a strong surface plasmon resonance effect in the visible light region,which exhibited an excellent surface enhanced Raman scattering effect.When the 4-mercaptobenzoic acid(4-MBA)molecules are modified,it can be efficiently used as Raman probe molecules to perform clear three-dimensional cell imaging.No matter when the nanoparticles are located inside the cell,outside the cell or partly inside the cell,they all can be clearly presented by this enhanced Raman probe molecule.These results provide a rapid and accurate method for three-dimensional imaging of cells,especially for tracking the phagocytosis of nanoparticles.展开更多
基金supported by the National Natural Science Foundation of China (21978325)。
文摘Constructing efficient carbon material with enhanced mass transfer ability from vacuum residuum(VR)is of prime industrial and scientific significance.Herein,we demonstrated a one-pot synthesis of metal-free and highly symmetric hollow carbon cubes(HCCs)using cost-efficient vacuum residuum(VR)as a C/N/S source.By multi-techniques such as TEM,SEM,Raman,XPS,and XRD,it is found that the CTAB surfactant plays an important role in emulsifying and forming oil-in-water suspension particles.Subsequently,high aromatics contents in VR favor the formation of HCCs shell by graphitization on the surface of Na Cl template.Notably,heavy metals(e.g.,V,Ni)are not enriched in carbon skeleton due to the unique graphitization mechanism.This metal-free HCCs catalyst showed good catalytic stability and high selectivity towards direct and local electrochemical production of hydrogen peroxide(H_(2)O_(2))through two-electron O_(2)reduction due to enhanced mass transfer ability.The results provide a novel avenue to synthesize metal-free cubic carbon material from low-cost and plentiful VR,which are essential to the design of more efficient catalysts for O_(2)reduction to H_(2)O_(2).
基金supported by the Foundation of Provincial Natural Science Research Project of Anhui Colleges(No.KJ2021ZD0047)the Anhui Provincial Natural Science Foundation(No.2008085J27)+1 种基金the China Postdoctoral Science Foundation(No.2019M652160)the Research Foundation of the Institute of Environment-friendly Materials and Occupational Health(Wuhu),Anhui University of Science and Technology(No.ALW2020YF05).
文摘The development of graphene-based composites with low density,robust absorption,wide bandwidth and thin thickness remained a great challenge in the field of electromagnetic(EM)absorption.In this work,nitrogen-doped reduced graphene oxide/hollow cobalt ferrite(NRGO/hollow CoFe_(2)O_(4))composite aerogels were constructed by a solvothermal and hydrothermal two-step route.Results demonstrated that the as-fabricated composite aerogels had the ultralow density and a unique three-dimensional(3D)network structure,and lots of hollow CoFe_(2)O_(4)microspheres were almost homogeneously distributed on the wrinkled surfaces of lamellar NRGO.Moreover,superior EM absorbing capacity could be achieved by modulating the ferrite structure,addition amounts of hollow CoFe_(2)O_(4)and thicknesses.It was noteworthy that the NRGO/hollow CoFe_(2)O_(4)composite aerogel with the addition amount of ferrite of 15.0 mg pos-sessed the minimum reflection loss of-44.7 dB and maximum absorption bandwidth of 5.2 GHz(from 12.6 to 17.8 GHz)at a very thin thickness of 1.8 mm and filling ratio of 15.0 wt.%.Furthermore,the possible EM attenuation mechanism had been proposed.The results of this work would be helpful for developing RGO-based 3D composites as lightweight,thin and highly efficient EM wave absorbers.
基金grants from the National Natural Science Foundation of China，Outstanding Scientific Fund of Shengjing Hospital
文摘Background： The accurate measurement of the femoral anteversion （FA） angle is always a topic of much debate in the orthopedic surgery and radiology research. We aimed to explore a new FA measurement method to acquire accurate results without radiation damage using piglet model. Methods： A total of thirty piglets were assigned to two groups based on the age. Bilateral femora were imaged with 3.0-T magnetic resonance （MR） and 64-slice computed tomography （CT） examinations on all piglets. FA was measured on MR-three-dimensional （3D） postprocessing software with a four-step method： initial validation of the femoral condylar axis, validation of the condylar plane, validation of the femoral neck axis, and line-plane angle measurement of FA. After MR and CT examinations, all piglets were sacrificed and their degree of FA was measured using their excised, dried femora. MR, CT, and dried-femur measurement results were analyzed statistically; M R and CT measurements were compared for accuracy against each other and against the gold standard dried femur measurement. Results： In both groups, the mean FA value measured by MR was lower than that measured by CT. A statistically significant difference was observed between CT- and dried-femur measurements but not between MR- and dried-femur measurements. A higher correlation （0.783 vs. 0.408） and a higher consistency （0.863 vs. 0.578） with dried-femur measurement results were seen for MR measurements than CT measurements in the 1 -week age group. However, in the 8-week age group, similar correlations （0.707 vs. 0.669） and consistencies （0.864 vs. 0.82 l ） were observed. Conclusions： Noninvasive MR-3D-Cube reconstruction was able to accurately measure FA in piglets. Particularly in the 1-week age group with a larger proportion of cartilaginous structures, the correlation and consistency between MR- and dried-femur measurement results were higher than those between CT- and dried-femur measurements, suggesting that MR may be a new useful examination tool for FA-related diseases in children.
基金funded by the National Natural Science Foundation of China(No.21776051)the Natural Science Foundations of Guangdong(No.2018A030313423)。
文摘A appropriate size with three-dimension(3 D) channels for lithium diffusion plays an important role in constructing highperforming LiNi_(0.5)Mn_(1.5)O_4(LNMO) cathode materials, as it can not only reduce the transport path of lithium ions and electrons, but also reduce the side effects and withstand the structural strain in the process of repetitive Li~+ intercalation/deintercalation. In this work, an e fficient method for designing the hollow LNMO microsphere with 3 D channels structure by using polyethylene oxide(PEO) as soft template agent assisted solvothermal method is proposed. Experimental results indicate that PEO can make the reagents mingle evenly and nucleate slowly in the solvothermal process, thus obtaining a homogeneous distribution of carbonate precursors. In the final LNMO products, the hollow 3 D channels structure obtained by the decomposition of PEO and carbonate precursor in the calcination can provide abundant electroactive zones and electron/ion transport paths during the charge/discharge process, which benefits to improve the cycling performance and rate capability. The LNMO prepared by adding 1 g PEO possesses the most outstanding electrochemical performance, which presented an excellent discharge capacity of 143.1 mAh g~(-1) at 0.1 C and with a capacity retention of 92.2% after 100 cycles at 1 C. The superior performance attributed to the 3 D channels structure of hollow microspheres, which provide uninterrupted conductive systems and therefore achieve the stable transfer for electron/ion.
基金supported by the National Natural Science Foundation of China(21575014)Beijing Natural Science Foundation(2184122)+3 种基金the Fundamental Research Funds for the Central Universities(2018CX01017)Beijing Institute of Technology Research Fund Program for Young Scholarsthe Project of State Key Laboratory of Explosion Science and Technology(Beijing Institute of Technology,YBKT18-03)Analysis&Testing Center,Beijing Institute of Technology
文摘Microelectrodes are a type of electrode with microscopic dimension, and due to their rapid diffusing rates, high electrical current densities and signal-to-noise ratios, they can help improve the detection sensitivity for various analytes [1]. Investigations on the fabrication and the application of microelectrodes are highly relevant. Fiber-type microelectrodes with one-dimensional (ID) microstructures that possess ID diffusion, particularly carbon fiber microelectrodes, have been widely fabricated and used in many different types of sensors due to their low cost, small volume, portability, and good biocompatibility [1,2]. However, poor electrocatalytic activity and low response currents preclude the applications of carbon fiber microelectrodes in sensors.
基金The authors would like to acknowledge support from the National Natural Science Foundation of China(51875518,51475419,and 81501607)the Natural Science Foundation of Zhejiang Province of China(LY15H160019)the Key Research and Development Projects of Zhejiang Province(2017C01054).
文摘Three-dimensional(3D)bioprinting is a rapidly growing technology that has been widely used in tissue engineering,disease studies,and drug screening.It provides the unprecedented capacity of depositing various types of biomaterials,cells,and biomolecules in a layer-by-layer fashion,with precisely controlled spatial distribution.This technology is expected to address the organ-shortage issue in the future.In this review,we first introduce three categories of 3D bioprinting strategies:inkjet-based printing(IBP),extrusion-based printing(EBP),and light-based printing(LBP).Biomaterials and cells,which are normally referred to as“bioinks,”are then discussed.We also systematically describe the recent advancements of 3D bioprinting in fabricating cell-laden artificial tissues and organs with solid or hollow structures,including cartilage,bone,skin,muscle,vascular network,and so on.The development of organs-onchips utilizing 3D bioprinting technology for drug discovery and toxicity testing is reviewed as well.Finally,the main challenges in current studies and an outlook of the future research of 3D bioprinting are discussed.
基金This work received financial support from the Science Foundation of Chinese Academy of Inspection and Quarantine(No.2017JK045)the National Key Research and Development Program of China(No.2017YFF0210003).
文摘The development of efficient three-dimensional cell imaging technology is a necessary means to study cell composition and structure,especially to track and monitor the phagocytosis process of nanoparticles by cells.Herein,we prepared a MoO_(2)hollow nanosphere with a strong surface plasmon resonance effect in the visible light region,which exhibited an excellent surface enhanced Raman scattering effect.When the 4-mercaptobenzoic acid(4-MBA)molecules are modified,it can be efficiently used as Raman probe molecules to perform clear three-dimensional cell imaging.No matter when the nanoparticles are located inside the cell,outside the cell or partly inside the cell,they all can be clearly presented by this enhanced Raman probe molecule.These results provide a rapid and accurate method for three-dimensional imaging of cells,especially for tracking the phagocytosis of nanoparticles.
