The practical application of silica-based composites as an alternative to commercial graphite anode materials is hampered by their large volumetric expansion,poor conductivity,and low Coulombic efficiency.In this work...The practical application of silica-based composites as an alternative to commercial graphite anode materials is hampered by their large volumetric expansion,poor conductivity,and low Coulombic efficiency.In this work,a novel silica/oxidized mesocarbon microbead/amorphous carbon(SiO2/O’MCMB/C)hierarchical structure in which SiO2 is sandwiched between spherical graphite and amorphous carbon shell was succes sfully fabricated through hydrogen bonding-assisted self-assembly and post-carbon coating method.The obtained three-layer hierarchical structure effectively accommodates the volumetric expansion of SiO2 and significantly enhances the electronic conductivity of composite materials.Moreover,the outer layer of amorphous carbon effectively increases the diffusion rate of lithium ions and promotes the formation of stable SEI film.As a result,the SiO2/O’MCMB/C composite exhibits superior electrochemical performance with a reversible capacity of 459.5 mA h/g in the first cycle,and the corresponding Coulombic efficiency is 62.8%.After 300 cycles,the capacity climbs to around 600 mA h/g.This synthetic route provides an efficient method for preparing SiO2 supported on graphite with excellent electrochemical performance,which is likely to promote its commercial applications.展开更多
AIM： To characterize whether a glaucoma model with chronic elevation of the intraocular pressure （IOP） was able to be induced by anterior chamber injection of microbeads in rabbits.METHODS： In order to screen the ...AIM： To characterize whether a glaucoma model with chronic elevation of the intraocular pressure （IOP） was able to be induced by anterior chamber injection of microbeads in rabbits.METHODS： In order to screen the optimal dose of microbead injection, IOP was measured every 3d for 4wk using handheld applanation tonometer after a single intracameral injection of 10 μL, 25 μL, 50 μL or 100 μL microbeads （5×10^6 beads/mL; n=6/group） in New Zealand White rabbits. To prolong IOP elevation, two intracameral injections of 50 μL microbeads or phosphate buffer saline （PBS） were made respectively at days 0 and 21 （n=24/group）. The fellow eye was not treated. At 5wk after the second injection of microbeads or PBS, bright-field microscopy and transmission electron microscopy （TEM） were used to assess the changes in the retina. The expression of glial fibrillary acidic protein （GFAP） in the retina was evaluated by immunofluorescence, quantitative real-time polymerase chain reaction and Western blot at 5wk after the second injection of microbeads.RESULTS： Following a single intracameral injection of 10 μL, 25 μL, 50 μL or 100 μL microbead, IOP levels showed a gradual increase and a later decrease over a 4wk period after a single injection of microbead into the anterior chamber of rabbits. A peak IOP was observed at day 15 after injection. No significant difference in peak value of IOP was found between 10 μL and 25 μL groups （17.13±1.25 mm Hg vs 17.63±0.74 mm Hg; P=0.346）. The peak value of IOP from 50 μL group （23.25±1.16 mm Hg） was significantly higher than 10 μL and 25 μL groups （all P〈0.05）. Administration of 100 μL microbead solution （23.00±0.93 mm Hg） did not lead to a significant increase in IOP compared to the 50 μL group （P=0.64）. A prolonged elevated IOP duration up to 8wk was achieved by administering two injections of 50 μL microbeads （20.48±1.21 mm Hg vs 13.60±0.90 mm Hg in PBS-injected group; P〈0.05）. The bright-field and TEM were use展开更多
A combined method of density functional theory (DFT) and statistics integral equation (SIE) for the determina-tion of the pore size distribution (PSD) is developed based on the experimental adsorption data of nitrogen...A combined method of density functional theory (DFT) and statistics integral equation (SIE) for the determina-tion of the pore size distribution (PSD) is developed based on the experimental adsorption data of nitrogen on acti-vated mesocarbon microbead (AMCMB) at 77 K. The pores of AMCMB are described as slit-shaped with PSD. Based on the PSD, methane adsorption and phase behavior are studied by the DFT method. Both nitrogen and methane molecules are modeled as Lennard-Jones spherical molecules, and the well-known Steeles 10-4-3 poten-tial is used to represent the interaction between the fluid molecule and the solid wall. In order to test the combined method and the PSD model, the Intelligent Gravimetric Analyzer (IGA-003) was used to measure the adsorption of methane on the AMCMB. The DFT results are in good agreement with the experimental data. Based on these facts, we predict the adsorption amount of methane, which can reach 32.3 w at 299 K and 4 MPa. The results indicate that the AMCMBs are a good candidate for adsorptive storage of methane and natural gas. In addition, the capillary condensation and hysteresis phenomenon of methane are also observed at 74.05 K.展开更多
Patients with chronic kidney disease are at high risk of hyperkalemia that is associated with various lifethreatening complications.Treatments primarily rely on orally administered potassium binding agents,along with ...Patients with chronic kidney disease are at high risk of hyperkalemia that is associated with various lifethreatening complications.Treatments primarily rely on orally administered potassium binding agents,along with low curative effects and various side effects.Herein,direct serum potassium uptake was realized via zeolite–heparin-mimicking-polymer hybrid microbeads.The preparation process involved the synthesis of the heparin-mimicking polymer via the in situ cross-linking polymerization of acrylic acid and N-vinylpyrrolidone in polyethersulfone solution,the fabrication of microbeads via zeolite-mixing,electro-spraying and phase-inversion,and the subsequent aqueous-phase modifications based on ion-exchange and metal-leaching.An ultra-high(about 88%)amount of zeolite could be incorporated and well locked inside the polymer matrix.Potassium uptake capability was verified in water,normal saline and human serum,showing high selectivity and fast adsorption.The microbeads exhibited satisfying blood compatibility,negligible hemolysis ratio,prolonged clotting time,inhibited contact activation,and enhanced antifouling property toward serum proteins and cells.The proposed approach toward zeolite–heparin-mimicking-polymer hybrid microbeads provided a cheap,efficient and safe treatment protocol of hyperkalemia for the high-risk patients.展开更多
AIM： To investigate the effect of microbead iridocorneal angle occlusion on intraocular pressure（IOP） diurnal fluctuation in rat eyes. METHODS： Male Dark Agouti（DA） rats, 8-10 week old, were each given a single ...AIM： To investigate the effect of microbead iridocorneal angle occlusion on intraocular pressure（IOP） diurnal fluctuation in rat eyes. METHODS： Male Dark Agouti（DA） rats, 8-10 week old, were each given a single intracameral injection of microbeads, followed by injection of dispersive viscoelastic solution. The right eye served as the experimental eye, while the left eye served as the control. IOP was measured twice daily postoperatively for 3 wk and compared between groups. At the end of 3 wk, the rats were sacrificed and the eyes were harvested for histological analysis and retinal ganglion cell（RGC） counting. RESULTS： After microbead injection, experimental eyes had significantly higher dark time IOP than controls from the second week to the third week [2 nd week： 22.92±1.631 mm Hg（n=5） vs 17.35±0.751 mm Hg（n=5）; 3 rd week： 23.59±1.494 mm Hg vs 17.73±0.592 mm Hg（n=5）], while light time IOP was comparable between groups. The fluctuation levels of IOP in the experimental eyes were 7.21±0.398 mm Hg（n=5）, 9.50±1.017 mm Hg（n=5） and 10.66±0.894 mm Hg（n=5） from the first week to the third week after injection. Comparatively, they were significantly lower in the control eyes, which were 4.69±0.323 mm Hg（n=5）, 2.84±1.122 mm Hg（n=5） and 4.98±0.603 mm Hg（n=5） respectively. However, at the end of 3 wk, the larger fluctuations in IOP in the experimental eyes was not associated with a significant loss of RGCs. CONCLUSION： Microbead occlusion exacerbates diurnal IOP fluctuation in rats. This reported model may serve as a method of investigating the pathological effects of IOP fluctuation. A longer observation period, or repeated injections, may be needed to observe a significant change in RGC density.展开更多
Microfluidic systems provide an interesting alternative to standard macroscale cell cultures due to the decrease in the number of cells and reagents as well as the improved physiology of cells confined to small volume...Microfluidic systems provide an interesting alternative to standard macroscale cell cultures due to the decrease in the number of cells and reagents as well as the improved physiology of cells confined to small volumes.However,the tools available for cell-secreted molecules inside microfluidic devices remain limited.In this paper,we describe an integrated microsystem composed of a microfluidic device and a fluorescent microbead-based assay for the detection of the hepatocyte growth factor(HGF)and the transforming growth factor(TGF)-β1 secreted by primary hepatocytes.This microfluidic system is designed to separate a cell culture chamber from sensing chambers using a permeable hydrogel barrier.Cell-secreted HGF and TGF-β1 diffuse through the hydrogel barrier into adjacent sensing channels and are detected using fluorescent microbead-based sensors.The specificity of sensing microbeads is defined by the choice of antibodies;therefore,our microfluidic culture system and sensing microbeads may be applied to a variety of cells and cell-secreted factors.展开更多
基金supported by the National Key Research and Development Program of China (No.2016YFB0100511)
文摘The practical application of silica-based composites as an alternative to commercial graphite anode materials is hampered by their large volumetric expansion,poor conductivity,and low Coulombic efficiency.In this work,a novel silica/oxidized mesocarbon microbead/amorphous carbon(SiO2/O’MCMB/C)hierarchical structure in which SiO2 is sandwiched between spherical graphite and amorphous carbon shell was succes sfully fabricated through hydrogen bonding-assisted self-assembly and post-carbon coating method.The obtained three-layer hierarchical structure effectively accommodates the volumetric expansion of SiO2 and significantly enhances the electronic conductivity of composite materials.Moreover,the outer layer of amorphous carbon effectively increases the diffusion rate of lithium ions and promotes the formation of stable SEI film.As a result,the SiO2/O’MCMB/C composite exhibits superior electrochemical performance with a reversible capacity of 459.5 mA h/g in the first cycle,and the corresponding Coulombic efficiency is 62.8%.After 300 cycles,the capacity climbs to around 600 mA h/g.This synthetic route provides an efficient method for preparing SiO2 supported on graphite with excellent electrochemical performance,which is likely to promote its commercial applications.
基金Supported by Shenzhen Science and Technology Innovation Committee in China(No.JCYJ20120831154554508No.JCYJ20140415174819509+1 种基金No.GJHZ20160229170608241)Medical Science and Technology Research Fund Project in Guangdong Province(No.A2015315)
文摘AIM： To characterize whether a glaucoma model with chronic elevation of the intraocular pressure （IOP） was able to be induced by anterior chamber injection of microbeads in rabbits.METHODS： In order to screen the optimal dose of microbead injection, IOP was measured every 3d for 4wk using handheld applanation tonometer after a single intracameral injection of 10 μL, 25 μL, 50 μL or 100 μL microbeads （5×10^6 beads/mL; n=6/group） in New Zealand White rabbits. To prolong IOP elevation, two intracameral injections of 50 μL microbeads or phosphate buffer saline （PBS） were made respectively at days 0 and 21 （n=24/group）. The fellow eye was not treated. At 5wk after the second injection of microbeads or PBS, bright-field microscopy and transmission electron microscopy （TEM） were used to assess the changes in the retina. The expression of glial fibrillary acidic protein （GFAP） in the retina was evaluated by immunofluorescence, quantitative real-time polymerase chain reaction and Western blot at 5wk after the second injection of microbeads.RESULTS： Following a single intracameral injection of 10 μL, 25 μL, 50 μL or 100 μL microbead, IOP levels showed a gradual increase and a later decrease over a 4wk period after a single injection of microbead into the anterior chamber of rabbits. A peak IOP was observed at day 15 after injection. No significant difference in peak value of IOP was found between 10 μL and 25 μL groups （17.13±1.25 mm Hg vs 17.63±0.74 mm Hg; P=0.346）. The peak value of IOP from 50 μL group （23.25±1.16 mm Hg） was significantly higher than 10 μL and 25 μL groups （all P〈0.05）. Administration of 100 μL microbead solution （23.00±0.93 mm Hg） did not lead to a significant increase in IOP compared to the 50 μL group （P=0.64）. A prolonged elevated IOP duration up to 8wk was achieved by administering two injections of 50 μL microbeads （20.48±1.21 mm Hg vs 13.60±0.90 mm Hg in PBS-injected group; P〈0.05）. The bright-field and TEM were use
基金Project supported by the Key Fundamental Research Plan (No. G2000048010) and the National Natural Science Foundation of China (Nos. 20236010 20276004).
文摘A combined method of density functional theory (DFT) and statistics integral equation (SIE) for the determina-tion of the pore size distribution (PSD) is developed based on the experimental adsorption data of nitrogen on acti-vated mesocarbon microbead (AMCMB) at 77 K. The pores of AMCMB are described as slit-shaped with PSD. Based on the PSD, methane adsorption and phase behavior are studied by the DFT method. Both nitrogen and methane molecules are modeled as Lennard-Jones spherical molecules, and the well-known Steeles 10-4-3 poten-tial is used to represent the interaction between the fluid molecule and the solid wall. In order to test the combined method and the PSD model, the Intelligent Gravimetric Analyzer (IGA-003) was used to measure the adsorption of methane on the AMCMB. The DFT results are in good agreement with the experimental data. Based on these facts, we predict the adsorption amount of methane, which can reach 32.3 w at 299 K and 4 MPa. The results indicate that the AMCMBs are a good candidate for adsorptive storage of methane and natural gas. In addition, the capillary condensation and hysteresis phenomenon of methane are also observed at 74.05 K.
基金This work was financially sponsored by the State Key Research Development Programme of China(Grant No.2016YFC1103000)the National Natural Science Foundation of China(No.51773127,51873115)+1 种基金Science and Technology Program of Sichuan Province(2019YJ0132)We gratefully acknowledge the help of the Analytical and Testing Center at Sichuan University for the SEM and XPS analysis.
文摘Patients with chronic kidney disease are at high risk of hyperkalemia that is associated with various lifethreatening complications.Treatments primarily rely on orally administered potassium binding agents,along with low curative effects and various side effects.Herein,direct serum potassium uptake was realized via zeolite–heparin-mimicking-polymer hybrid microbeads.The preparation process involved the synthesis of the heparin-mimicking polymer via the in situ cross-linking polymerization of acrylic acid and N-vinylpyrrolidone in polyethersulfone solution,the fabrication of microbeads via zeolite-mixing,electro-spraying and phase-inversion,and the subsequent aqueous-phase modifications based on ion-exchange and metal-leaching.An ultra-high(about 88%)amount of zeolite could be incorporated and well locked inside the polymer matrix.Potassium uptake capability was verified in water,normal saline and human serum,showing high selectivity and fast adsorption.The microbeads exhibited satisfying blood compatibility,negligible hemolysis ratio,prolonged clotting time,inhibited contact activation,and enhanced antifouling property toward serum proteins and cells.The proposed approach toward zeolite–heparin-mimicking-polymer hybrid microbeads provided a cheap,efficient and safe treatment protocol of hyperkalemia for the high-risk patients.
文摘AIM： To investigate the effect of microbead iridocorneal angle occlusion on intraocular pressure（IOP） diurnal fluctuation in rat eyes. METHODS： Male Dark Agouti（DA） rats, 8-10 week old, were each given a single intracameral injection of microbeads, followed by injection of dispersive viscoelastic solution. The right eye served as the experimental eye, while the left eye served as the control. IOP was measured twice daily postoperatively for 3 wk and compared between groups. At the end of 3 wk, the rats were sacrificed and the eyes were harvested for histological analysis and retinal ganglion cell（RGC） counting. RESULTS： After microbead injection, experimental eyes had significantly higher dark time IOP than controls from the second week to the third week [2 nd week： 22.92±1.631 mm Hg（n=5） vs 17.35±0.751 mm Hg（n=5）; 3 rd week： 23.59±1.494 mm Hg vs 17.73±0.592 mm Hg（n=5）], while light time IOP was comparable between groups. The fluctuation levels of IOP in the experimental eyes were 7.21±0.398 mm Hg（n=5）, 9.50±1.017 mm Hg（n=5） and 10.66±0.894 mm Hg（n=5） from the first week to the third week after injection. Comparatively, they were significantly lower in the control eyes, which were 4.69±0.323 mm Hg（n=5）, 2.84±1.122 mm Hg（n=5） and 4.98±0.603 mm Hg（n=5） respectively. However, at the end of 3 wk, the larger fluctuations in IOP in the experimental eyes was not associated with a significant loss of RGCs. CONCLUSION： Microbead occlusion exacerbates diurnal IOP fluctuation in rats. This reported model may serve as a method of investigating the pathological effects of IOP fluctuation. A longer observation period, or repeated injections, may be needed to observe a significant change in RGC density.
基金Financial support for this project was provided by grants from NIH(R01DK079977)NSF(1403561)to AR and from NSF(GRFP 1650042)to PG.
文摘Microfluidic systems provide an interesting alternative to standard macroscale cell cultures due to the decrease in the number of cells and reagents as well as the improved physiology of cells confined to small volumes.However,the tools available for cell-secreted molecules inside microfluidic devices remain limited.In this paper,we describe an integrated microsystem composed of a microfluidic device and a fluorescent microbead-based assay for the detection of the hepatocyte growth factor(HGF)and the transforming growth factor(TGF)-β1 secreted by primary hepatocytes.This microfluidic system is designed to separate a cell culture chamber from sensing chambers using a permeable hydrogel barrier.Cell-secreted HGF and TGF-β1 diffuse through the hydrogel barrier into adjacent sensing channels and are detected using fluorescent microbead-based sensors.The specificity of sensing microbeads is defined by the choice of antibodies;therefore,our microfluidic culture system and sensing microbeads may be applied to a variety of cells and cell-secreted factors.
