Thermal barrier coatings(TBCs)can effectively protect the alloy substrate of hot components in aeroengines or land-based gas turbines by the thermal insulation and corrosion/erosion resistance of the ceramic top coat....Thermal barrier coatings(TBCs)can effectively protect the alloy substrate of hot components in aeroengines or land-based gas turbines by the thermal insulation and corrosion/erosion resistance of the ceramic top coat.However,the continuous pursuit of a higher operating temperature leads to degradation,delamination,and premature failure of the top coat.Both new ceramic materials and new coating structures must be developed to meet the demand for future advanced TBC systems.In this paper,the latest progress of some new ceramic materials is first reviewed.Then,a comprehensive spalling mechanism of the ceramic top coat is summarized to understand the dependence of lifetime on various factors such as oxidation scale growth,ceramic sintering,erosion,and calcium–magnesium–aluminium–silicate(CMAS)molten salt corrosion.Finally,new structural design methods for high-performance TBCs are discussed from the perspectives of lamellar,columnar,and nanostructure inclusions.The latest developments of ceramic top coat will be presented in terms of material selection,structural design,and failure mechanism,and the comprehensive guidance will be provided for the development of next-generation advanced TBCs with higher temperature resistance,better thermal insulation,and longer lifetime.展开更多
Two ligand oligopeptides GV1 and GV2 were designed according to the putative binding region of VEGF to its receptors. GV1, GV2 and endosome releasing oligopeptide HA20 were conjugated with poly-L-lysine or protamine a...Two ligand oligopeptides GV1 and GV2 were designed according to the putative binding region of VEGF to its receptors. GV1, GV2 and endosome releasing oligopeptide HA20 were conjugated with poly-L-lysine or protamine and the resulting conjugates could interact with DNA in a noncovalent bond to form a complex. Using pSV2-β-galactosidase as a reporter gene, it has been demonstrated that exogenous gene was transferred into bovine aortic arch-derived endothelial cells (ABAE) andhuman malignant melanoma cell lines (A375) in vitro. In vivo experiments, exogenous gene was transferred into tumor vascular endothelial cells and tumor cells of subcutaneously transplanted human colon cancer LOVO, human malignant melanoma A375 and human hepatoma graft in nude mice. This system could also target gene to intrahepatically transplanted human hepatoma injected via portal vein in nude mice. These results are correlated with theGene delivery system targeting VEGF receptors relevant receptors (flt-1, flk-1/KDR) expression on the targeted cells and tissues.展开更多
目的通过超声测量产妇不同体位肱动脉峰流速的变化,探讨其预测腰麻后发生仰卧位低血压综合征(supine hypotension syndrome,SHS)的有效性。方法拟在腰麻下行择期剖宫产的单胎产妇,ASAⅠ或Ⅱ级,根据腰麻后是否发生SHS(上肢SBP下降30 mm H...目的通过超声测量产妇不同体位肱动脉峰流速的变化,探讨其预测腰麻后发生仰卧位低血压综合征(supine hypotension syndrome,SHS)的有效性。方法拟在腰麻下行择期剖宫产的单胎产妇,ASAⅠ或Ⅱ级,根据腰麻后是否发生SHS(上肢SBP下降30 mm Hg或下降至80 mm Hg以下)分为SHS组和非SHS组。记录麻醉前仰卧位与左侧卧位的HR、SBP、DBP,同时超声测量肱动脉峰流速。并计算变换体位前后上述指标的差值(Δ),对组间比较有统计学意义的指标绘制受试者工作特征(ROC)曲线,评价各指标对腰麻后发生SHS的预测作用。结果纳入196例产妇,有89例(45.4%)腰麻后发生了SHS。SHS组ΔSBP、ΔDBP、肱动脉峰流速最小值差值(ΔVpmin)、肱动脉峰流速变异度差值(ΔΔVp)明显高于非SHS组(P<0.05),ΔSBP、ΔDBP、ΔVpmin、ΔΔVp的受试者工作特征曲线下面积(AUC)分别为0.711(95%CI 0.575~0.846)、0.573(95%CI 0.419~0.727)、0.948(95%CI0.895~0.987)、0.864(95%CI 0.770~0.958),诊断界值分别为17.5 mm Hg、7.6 mm Hg、17.8 cm/s、13.1%。结论产妇不同体位下超声测量肱动脉峰流速差值可有效预测腰麻后SHS的发生,其中ΔVpmin≥17.8 cm/s有较好的预测作用。展开更多
Unlike inorganic quantum dots,fluorescent graphene quantum dots(GQDs)display excitation-dependent multiple color emission.In this study,we report N-doped GQDs(N-GQDs)with tailored single color emission by tuning p-con...Unlike inorganic quantum dots,fluorescent graphene quantum dots(GQDs)display excitation-dependent multiple color emission.In this study,we report N-doped GQDs(N-GQDs)with tailored single color emission by tuning p-conjugation degree,which is comparable to the inorganic quantum dot.Starting from citric acid and diethylenetriamine,as prepared N-GQDs display blue,green,and yellow light emission by changing the reaction solvent from water,dimethylformamide(DMF),and solvent free.The X-ray photoelectron spectroscopy,ultraviolet-visible spectra results clearly show the N-GQDs with blue emission(N-GQDs-B)have relatively short effective conjugation length and more carboxyl group because H_(2)O is a polar protic solvent,which tends to donate proton to the reagent to depress the H_(2)O elimination reaction.On the other hand,the polar aprotic solvent(DMF)cannot donate hydrogen,the elimination of H_(2)O is promoted and more nitrogen units enter GQD framework.With the increase of effective p-conjugation length and N content,the emission band of N-GQDS red-shifts to green and yellow.We also demonstrate that N-GQDs could be a potential great biomarker for fluorescent bioimaging.展开更多
Background：Hepatitis B is an immune response-mediated disease.The aim of this study was to explore the differences of ratios of T-helper （Th） 2 cells to Thl cells and cytokine levels in acute hepatitis B （AHB） pa...Background：Hepatitis B is an immune response-mediated disease.The aim of this study was to explore the differences of ratios of T-helper （Th） 2 cells to Thl cells and cytokine levels in acute hepatitis B （AHB） patients and chronic hepatitis B virus （HBV）-infected patients in immune-tolerance and immune-active phases.Methods：Thirty chronic HBV-infected patients in the immune-tolerant phase （IT group） and 50 chronic hepatitis B patients in the immuneactive （clearance） phase （IC group）,32 AHB patients （AHB group）,and 13 healthy individuals （HI group） were enrolled in the study.Th cell proportions in peripheral blood,cytokine levels in plasma,and serum levels of HBV DNA,hepatitis B surface antigen,and hepatitis B e antigen were detected.Results：The Th1 cell percentage and Th2/Th1 ratio in the HBV infection group （including IT,IC,and AHB groups） were significantly different from those in HI group （24.10% ± 8.66% and 1.72 ± 0.61 vs.15.16% ± 4.34% and 2.40 ± 0.74,respectively;all P 〈 0.001）.However,there were no differences in the Th1 cell percentages and Th2/Th1 ratios among the IT,IC,and AHB groups.In HBV infection group,the median levels of Flt3 ligand （Flt3L）,interferon （IFN）-γ,and interleukin （IL）-17A were significantly lower than those in HI group （29.26 pg/ml,33.72 pg/ml,and 12.27 pg/ml vs.108.54 pg/ml,66.48 pg/ml,and 35.96 pg/ml,respectively;all P 〈 0.05）.IFN-α2,IL-10,and transforming growth factor （TGF）-β2 median levels in hepatitis group （including patients in AHB and IC groups） were significantly higher than those in IT group （40.14 pg/ml,13.58 pg/ml,and 557.41 pg/ml vs.16.74 pg/ml,6.80 pg/ml,and 419.01 pg/ml,respectively;all P 〈 0.05）,while patients in hepatitis group had significant lower Flt3L level than IT patients （30.77 vs.59.96 pg/ml,P =0.021）.Compared with IC group,patients in AHB group had significant higher median level s of IL-1 0,TGF-β 1,and TGF-β2 （22.77 pg/ml,10,447.00 pg/ml,and 782.28 pg/ml vs.8.66 pg展开更多
A field experiment from 18 August to 8 September 2006 in Beijing, China, was carried out. A hazy day was defined as visibility 〈 10 km and RH（relative humidity） 〈 90%. Four haze episodes, which accounted for ～ 60...A field experiment from 18 August to 8 September 2006 in Beijing, China, was carried out. A hazy day was defined as visibility 〈 10 km and RH（relative humidity） 〈 90%. Four haze episodes, which accounted for ～ 60% of the time during the whole campaign, were characterized by increases of SNA（sulfate, nitrate, and ammonium） and SOA（secondary organic aerosol） concentrations. The average values with standard deviation of SO2-＋4, NO-3, NH4 and SOA were 49.8（± 31.6）, 31.4（±22.3）, 25.8（±16.6） and 8.9（±4.1） μg/m3, respectively, during the haze episodes, which were 4.3, 3.4, 4.1, and 1.7 times those in the non-haze days. The SO2-4,NO-3, NH＋4, and SOA accounted for 15.8%, 8.8%, 7.3%, and 6.0% of the total mass concentration of PM10 during the non-haze days. The respective contributions of SNA species to PM10 rose to about27.2%, 15.9%, and 13.9% during the haze days, while the contributions of SOA maintained the same level with a slight decrease to about 4.9%. The observed mass concentrations of SNA and SOA increased with the increase of PM10 mass concentration, however, the rate of increase of SNA was much faster than that of the SOA. The SOR（sulfur oxidation ratio） and NOR（nitrogen oxidation ratio） increased from non-haze days to hazy days, and increased with the increase of RH. High concentrations of aerosols and water vapor favored the conversion of SO2 to SO2-4and NO2 to NO-3, which accelerated the accumulation of the aerosols and resulted in the formation of haze in Beijing.展开更多
Camouflage technology has attracted growing interest for many thermal applications.Previous experimental demonstrations of thermal camouflage technology have not adequately explored the ability to continuously camoufl...Camouflage technology has attracted growing interest for many thermal applications.Previous experimental demonstrations of thermal camouflage technology have not adequately explored the ability to continuously camouflage objects either at varying background temperatures or for wide observation angles.In this study,a thermal camouflage device incorporating the phase-changing material Ge2Sb2Te5(GST)is experimentally demonstrated.It has been shown that near-perfect thermal camouflage can be continuously achieved for background temperatures ranging from 30℃ to 50℃ by tuning the emissivity of the device,which is attained by controlling the GST phase change.The thermal camouflage is robust when the observation angle is changed from 0°to 60°.This demonstration paves the way toward dynamic thermal emission control both within the scientific field and for practical applications in thermal information.展开更多
文摘Thermal barrier coatings(TBCs)can effectively protect the alloy substrate of hot components in aeroengines or land-based gas turbines by the thermal insulation and corrosion/erosion resistance of the ceramic top coat.However,the continuous pursuit of a higher operating temperature leads to degradation,delamination,and premature failure of the top coat.Both new ceramic materials and new coating structures must be developed to meet the demand for future advanced TBC systems.In this paper,the latest progress of some new ceramic materials is first reviewed.Then,a comprehensive spalling mechanism of the ceramic top coat is summarized to understand the dependence of lifetime on various factors such as oxidation scale growth,ceramic sintering,erosion,and calcium–magnesium–aluminium–silicate(CMAS)molten salt corrosion.Finally,new structural design methods for high-performance TBCs are discussed from the perspectives of lamellar,columnar,and nanostructure inclusions.The latest developments of ceramic top coat will be presented in terms of material selection,structural design,and failure mechanism,and the comprehensive guidance will be provided for the development of next-generation advanced TBCs with higher temperature resistance,better thermal insulation,and longer lifetime.
文摘Two ligand oligopeptides GV1 and GV2 were designed according to the putative binding region of VEGF to its receptors. GV1, GV2 and endosome releasing oligopeptide HA20 were conjugated with poly-L-lysine or protamine and the resulting conjugates could interact with DNA in a noncovalent bond to form a complex. Using pSV2-β-galactosidase as a reporter gene, it has been demonstrated that exogenous gene was transferred into bovine aortic arch-derived endothelial cells (ABAE) andhuman malignant melanoma cell lines (A375) in vitro. In vivo experiments, exogenous gene was transferred into tumor vascular endothelial cells and tumor cells of subcutaneously transplanted human colon cancer LOVO, human malignant melanoma A375 and human hepatoma graft in nude mice. This system could also target gene to intrahepatically transplanted human hepatoma injected via portal vein in nude mice. These results are correlated with theGene delivery system targeting VEGF receptors relevant receptors (flt-1, flk-1/KDR) expression on the targeted cells and tissues.
文摘目的通过超声测量产妇不同体位肱动脉峰流速的变化,探讨其预测腰麻后发生仰卧位低血压综合征(supine hypotension syndrome,SHS)的有效性。方法拟在腰麻下行择期剖宫产的单胎产妇,ASAⅠ或Ⅱ级,根据腰麻后是否发生SHS(上肢SBP下降30 mm Hg或下降至80 mm Hg以下)分为SHS组和非SHS组。记录麻醉前仰卧位与左侧卧位的HR、SBP、DBP,同时超声测量肱动脉峰流速。并计算变换体位前后上述指标的差值(Δ),对组间比较有统计学意义的指标绘制受试者工作特征(ROC)曲线,评价各指标对腰麻后发生SHS的预测作用。结果纳入196例产妇,有89例(45.4%)腰麻后发生了SHS。SHS组ΔSBP、ΔDBP、肱动脉峰流速最小值差值(ΔVpmin)、肱动脉峰流速变异度差值(ΔΔVp)明显高于非SHS组(P<0.05),ΔSBP、ΔDBP、ΔVpmin、ΔΔVp的受试者工作特征曲线下面积(AUC)分别为0.711(95%CI 0.575~0.846)、0.573(95%CI 0.419~0.727)、0.948(95%CI0.895~0.987)、0.864(95%CI 0.770~0.958),诊断界值分别为17.5 mm Hg、7.6 mm Hg、17.8 cm/s、13.1%。结论产妇不同体位下超声测量肱动脉峰流速差值可有效预测腰麻后SHS的发生,其中ΔVpmin≥17.8 cm/s有较好的预测作用。
基金The authors thank the National Natural Science Foundation of China(No.21301166,21201159,61306081,and 61176016)Science and Technology Department of Jilin Province(No.20130522127JH)are gratefully acknowledged+1 种基金ZS thanks the support of the‘Hundred Talent Program’of CAS and Innovation and Entrepreneurship Program of JilinThe project was supported by Open Research Fund of State Key Laboratory of Polymer Physics and Chemistry and the open research fund program of the State Key Laboratory of Luminescence and Applications.
文摘Unlike inorganic quantum dots,fluorescent graphene quantum dots(GQDs)display excitation-dependent multiple color emission.In this study,we report N-doped GQDs(N-GQDs)with tailored single color emission by tuning p-conjugation degree,which is comparable to the inorganic quantum dot.Starting from citric acid and diethylenetriamine,as prepared N-GQDs display blue,green,and yellow light emission by changing the reaction solvent from water,dimethylformamide(DMF),and solvent free.The X-ray photoelectron spectroscopy,ultraviolet-visible spectra results clearly show the N-GQDs with blue emission(N-GQDs-B)have relatively short effective conjugation length and more carboxyl group because H_(2)O is a polar protic solvent,which tends to donate proton to the reagent to depress the H_(2)O elimination reaction.On the other hand,the polar aprotic solvent(DMF)cannot donate hydrogen,the elimination of H_(2)O is promoted and more nitrogen units enter GQD framework.With the increase of effective p-conjugation length and N content,the emission band of N-GQDS red-shifts to green and yellow.We also demonstrate that N-GQDs could be a potential great biomarker for fluorescent bioimaging.
文摘Background：Hepatitis B is an immune response-mediated disease.The aim of this study was to explore the differences of ratios of T-helper （Th） 2 cells to Thl cells and cytokine levels in acute hepatitis B （AHB） patients and chronic hepatitis B virus （HBV）-infected patients in immune-tolerance and immune-active phases.Methods：Thirty chronic HBV-infected patients in the immune-tolerant phase （IT group） and 50 chronic hepatitis B patients in the immuneactive （clearance） phase （IC group）,32 AHB patients （AHB group）,and 13 healthy individuals （HI group） were enrolled in the study.Th cell proportions in peripheral blood,cytokine levels in plasma,and serum levels of HBV DNA,hepatitis B surface antigen,and hepatitis B e antigen were detected.Results：The Th1 cell percentage and Th2/Th1 ratio in the HBV infection group （including IT,IC,and AHB groups） were significantly different from those in HI group （24.10% ± 8.66% and 1.72 ± 0.61 vs.15.16% ± 4.34% and 2.40 ± 0.74,respectively;all P 〈 0.001）.However,there were no differences in the Th1 cell percentages and Th2/Th1 ratios among the IT,IC,and AHB groups.In HBV infection group,the median levels of Flt3 ligand （Flt3L）,interferon （IFN）-γ,and interleukin （IL）-17A were significantly lower than those in HI group （29.26 pg/ml,33.72 pg/ml,and 12.27 pg/ml vs.108.54 pg/ml,66.48 pg/ml,and 35.96 pg/ml,respectively;all P 〈 0.05）.IFN-α2,IL-10,and transforming growth factor （TGF）-β2 median levels in hepatitis group （including patients in AHB and IC groups） were significantly higher than those in IT group （40.14 pg/ml,13.58 pg/ml,and 557.41 pg/ml vs.16.74 pg/ml,6.80 pg/ml,and 419.01 pg/ml,respectively;all P 〈 0.05）,while patients in hepatitis group had significant lower Flt3L level than IT patients （30.77 vs.59.96 pg/ml,P =0.021）.Compared with IC group,patients in AHB group had significant higher median level s of IL-1 0,TGF-β 1,and TGF-β2 （22.77 pg/ml,10,447.00 pg/ml,and 782.28 pg/ml vs.8.66 pg
基金supported by the National Natural Science Foundation of China (Nos. 41475113, 41175018)the CAS Strategic Priority Research Program (No. XDB05010500)
文摘A field experiment from 18 August to 8 September 2006 in Beijing, China, was carried out. A hazy day was defined as visibility 〈 10 km and RH（relative humidity） 〈 90%. Four haze episodes, which accounted for ～ 60% of the time during the whole campaign, were characterized by increases of SNA（sulfate, nitrate, and ammonium） and SOA（secondary organic aerosol） concentrations. The average values with standard deviation of SO2-＋4, NO-3, NH4 and SOA were 49.8（± 31.6）, 31.4（±22.3）, 25.8（±16.6） and 8.9（±4.1） μg/m3, respectively, during the haze episodes, which were 4.3, 3.4, 4.1, and 1.7 times those in the non-haze days. The SO2-4,NO-3, NH＋4, and SOA accounted for 15.8%, 8.8%, 7.3%, and 6.0% of the total mass concentration of PM10 during the non-haze days. The respective contributions of SNA species to PM10 rose to about27.2%, 15.9%, and 13.9% during the haze days, while the contributions of SOA maintained the same level with a slight decrease to about 4.9%. The observed mass concentrations of SNA and SOA increased with the increase of PM10 mass concentration, however, the rate of increase of SNA was much faster than that of the SOA. The SOR（sulfur oxidation ratio） and NOR（nitrogen oxidation ratio） increased from non-haze days to hazy days, and increased with the increase of RH. High concentrations of aerosols and water vapor favored the conversion of SO2 to SO2-4and NO2 to NO-3, which accelerated the accumulation of the aerosols and resulted in the formation of haze in Beijing.
基金supported by the National Key Research and Development Program of China(Grant Number 2017YFA0205700)the National Natural Science Foundation of China(Grant Numbers 61425023,61575177,and 61235007).
文摘Camouflage technology has attracted growing interest for many thermal applications.Previous experimental demonstrations of thermal camouflage technology have not adequately explored the ability to continuously camouflage objects either at varying background temperatures or for wide observation angles.In this study,a thermal camouflage device incorporating the phase-changing material Ge2Sb2Te5(GST)is experimentally demonstrated.It has been shown that near-perfect thermal camouflage can be continuously achieved for background temperatures ranging from 30℃ to 50℃ by tuning the emissivity of the device,which is attained by controlling the GST phase change.The thermal camouflage is robust when the observation angle is changed from 0°to 60°.This demonstration paves the way toward dynamic thermal emission control both within the scientific field and for practical applications in thermal information.
