Photocatalysis driven by near-infrared(NIR)light is of scientific and technological interest for ex-ploiting solar energy.In this study,we demonstrate a facile hydrothermal process to synthesize core-shell nanoparti...Photocatalysis driven by near-infrared(NIR)light is of scientific and technological interest for ex-ploiting solar energy.In this study,we demonstrate a facile hydrothermal process to synthesize core-shell nanoparticles combining upconversion nanoparticles(UCNPs)and alloyed ZnxCwhich can be excited using NIR or visible light.Morphologies,phase,and chemical composition have been investigated using field-emission scanning electron microscopy,transmission electron mi-croscopy,X-ray diffraction analysis,and atomic absorption spectroscopy.Moreover,we found that amorphous TiO2 layers existing in the final samples play an important role in formation ofyolk-shell nanoparticles,which bind the as-prepared ZnxCnanoparticlescan be tuna-ble by adjusting the amount of the Cd and Zn source compounds.The photochemical reduction of Cr(Ⅵ)in water has been performed to study the photocatalytic performance under irradiation by NIR light or a simulated solar light,showing efficient photoreduction and Cr(Ⅵ)removal over the/TiO2 yolk-shell nanoparticles.The as-prepared UCNPs@ZnxC/TiO2 nanoparticles show excellent production of hydroxyl radicals,which are responsible for the photochemical reduction of Cr(Ⅵ)to Cr(Ⅲ).This study will provide an alternative strategy for en-vironmental wastewater treatment,making full use of solar energy.展开更多
We report a colloidal process to coat a layer of TiO2onto SiO2composite nanofibers containing embedded CdS and upconversion nanoparticles(UCNPs).The SiO2composite nanofibers were fabricated by electrospinning.To impro...We report a colloidal process to coat a layer of TiO2onto SiO2composite nanofibers containing embedded CdS and upconversion nanoparticles(UCNPs).The SiO2composite nanofibers were fabricated by electrospinning.To improve the energy transfer efficiency,UCNPs and CdS nanoparticles were bound in close proximity to each other within the SiO2matrix.β‐NaYF4:Yb(30%),Tm(0.5%)@NaYF4:Yb(20%),Er(2%)core–shell nanoparticles were used as nanotransducers for near infrared light.These nanoparticles exhibited enhanced upconversion fluorescence compared withβ‐NaYF4:Yb(30%),Tm(0.5%)orβ–NaYF4:Yb(30%),Tm(0.5%)@NaYF4nanoparticles.The morphologies,size and chemical compositions have been extensively investigated using field emission scanning electron microscopy(FESEM),transmission electron microscopy(TEM),X‐ray diffraction(XRD)and X‐ray photoelectron spectra(XPS),respectively.The TEM images showed that the TiO2composite nanotubes were embedded with a large amount of UCNPs and CdS nanoparticles.The composite TiO2nanotubes degraded more than90%of rhodamine B(RhB)dye during20min of irradiation by simulated solar light.In particular,more than50%of RhB was decomposed in70min,under irradiation of near infrared light(NIR).This high degradation was attributed to the full spectrum absorption of solar light,and the enhanced transfer efficiency for near infrared light.The as‐prepared nanostructures can harness solar energy,and provide an alternative to overcome energy shortages and environmental protection.展开更多
Quantitative prediction of distribution function and adhesionefficiency of particles around a rising bubble in slurry systems ispresented in this work. By solving the convection-diffusion equation(Fokker-Planck equati...Quantitative prediction of distribution function and adhesionefficiency of particles around a rising bubble in slurry systems ispresented in this work. By solving the convection-diffusion equation(Fokker-Planck equation), the influence of Brownian diffusivity offine particles on concentration distribution and adhesion efficiencyis demonstrated with the hydrodynamic force and van der Waalsattractive potential between particles and bubble considered. It isfound that two kinds of mechanism dominate the adhesion process ofparticles on bubble according to different Peclet number or size ofparticles and bubble, as well as other properties of the slurrysystems. In addition, the viscosity ratio of bubble to the suspendingfluid was found to have obvious influence on particle adhesion.展开更多
This review examines the organizational principles underlying olfactory learning in three specialized contexts that occur during sensitive periods of enhanced neural plasticity and emphasizes some of their common feat...This review examines the organizational principles underlying olfactory learning in three specialized contexts that occur during sensitive periods of enhanced neural plasticity and emphasizes some of their common features. All three forms of olfactory learning are associated with neural changes in the olfactory bulb (OB) at the first stage of sensory processing. These changes require the association of the olfactory and somatosensory signals in the OB. They all depend on somatosensory stimulation-induced release of noradrenaline that induces structural and functional changes at mitral-granule cell reciprocal synapses in the OB, resulting in increases in inhibitory transmission. In the accessory olfactory bulb, this represents the enhanced self-inhibition of mitral cells, which selectively disrupts the transmission of the mating male's pregnancy-blocking signal at this level. In contrast, an extensive network of secondary dendrites of mitral cells in the main olfactory bulb probably results in a sharpening of the odor-induced pattern of activity, due to increases in lateral inhibition, leading to offspring recognition in sheep and neonatal learning in rats and rabbits. These findings show that inhibitory intemeurons play a critical role in olfactory learning. Further work on how these neurons shape olfactory circuit function could provide important clues to understand memory functions of interneurons in other systems. Moreover, recent research has suggested that three forms of olfactory learning are controlled by synergistic, redundant, and distributed neural mechanisms. This has general implications regarding the mechanisms that may contribute to the robustness of memories [Current Zoology 56 (6): 819-833, 2010].展开更多
Objective:The paper aimed to study the relationship between the expressions of immunoglobulin G(IgG) subclasses toward human papillomavirus 16-like particles(HPV16VLPs) in the serum of patients and different grades of...Objective:The paper aimed to study the relationship between the expressions of immunoglobulin G(IgG) subclasses toward human papillomavirus 16-like particles(HPV16VLPs) in the serum of patients and different grades of cervical lesions.Methods:The expressions of IgG subclasses in 32 cases of human papillomavirus(HPV) infection,30 cervical intraepithelial neoplasia(CIN I),43 CIN Ⅱ-Ⅲ,and 24 hysteromyoma and chronic cervicitis were examined by ELISA.Results:The absorbance values of HPV16VLPs-IgG,IgG1 increased with the grade of CIN(P < 0.05).The IgG2 dominance(IgG2/IgG1 ratio > 1) from control group was 100%,87.50% for HPV infection group,75% for CIN I group,compared with that from CIN Ⅱ-Ⅲ patients(9.52%)(P < 0.05).The positive rates and absorbance values of HPV16VLPs-IgG,IgG1 and IgG2 from HPV16-DNA positive group were significantly higher than those from non-HPV16-DNA positive group(P < 0.05).There was a moderate correlation between the HPV16-DNA testing and detection of HPV16VLPs-IgG(r = 0.531,P < 0.05).Conclusion:An increase of the expressions of HPV16VLPs-IgG and its subclasses in the serum of the patients with cervical precancerous lesions,especially those with CIN II-III,might be associated with duration of HPV infection and severity of cervical lesions.An increase of the IgG2 dominance(IgG2/IgG1 > 1) in serum from low grade cervical lesions group and normal control group,might indicate the clearance of HPV infection and the regression of cervical lesions.展开更多
Highly luminescent upconversion nanoparticles (UCNPs) with small sizes are highly desirable for bioapplications. A facile in situ cation exchange strategy has been developed to greatly enhance the UC luminescence of...Highly luminescent upconversion nanoparticles (UCNPs) with small sizes are highly desirable for bioapplications. A facile in situ cation exchange strategy has been developed to greatly enhance the UC luminescence of hexagonal phase NaYF4 NPs while maintaining their small particle size and shape. Via a cation exchange treatment by hot-injecting Gd3+ precursors into the as-prepared NPs solution without pre-separation, the naked-eye visible UC emission of the NPs was enhanced about 29 times under 980 nm near infrared (NIR) excitation with unchanged particle size. The cation exchange process was further demonstrated for the case of NaYF4 nanorods (NRs). After the cation exchange, the nanorod was broken into two NPs with stronger emission. The cation exchanged hydrophobic UCNPs were further encapSulated with poly(amino acid) and successfully applied for targeted cancer cell UC luminescence imaging.展开更多
The coupling of upconversion nanophosphors (UCNPs) with the surface plasmonic resonance (SPR) of noble metals is a promising way to improve luminescent efficiency of UCNPs; however, it is still a challenge to achi...The coupling of upconversion nanophosphors (UCNPs) with the surface plasmonic resonance (SPR) of noble metals is a promising way to improve luminescent efficiency of UCNPs; however, it is still a challenge to achieve stable, reproducible and effective upconversion luminescence (UCL) enhancement through such coupling. In this work, we present a novel strategy to improve UCL of NaYF4:ybB,Er3. UCNPs, by combining the near-field coupling of SPR of silver and the far-field coupling of poly(methyl methacrylate) (PMMA) opal photonic crystals (OPCs) with the UCNPs. In order to control the effective interaction distance between the UCNPs and the SPR, a porous silver film consisting of randomly distributed silver nanoparticles (NPs) (〉 100 nm) was prepared which demonstrated strong SPR over a broad wavelength range, and its coupling to the UCNPs was found to be much stronger than that of a dense film. In the far-field coupling of OPCs, the photonic stop band (PSB) of the PMMA OPCs was tuned to 980 nm, matching exactly the excitation light. By modulating the particle size of the UCNPs, and the direction and excitation power of the incident light, a maximum enhancement of 60-fold was observed, which is an important advance for metaMnduced UCL enhancement systems.展开更多
基金supported by the National Natural Science Foundation of China (21471043, 51603059, 31501576)~~
文摘Photocatalysis driven by near-infrared(NIR)light is of scientific and technological interest for ex-ploiting solar energy.In this study,we demonstrate a facile hydrothermal process to synthesize core-shell nanoparticles combining upconversion nanoparticles(UCNPs)and alloyed ZnxCwhich can be excited using NIR or visible light.Morphologies,phase,and chemical composition have been investigated using field-emission scanning electron microscopy,transmission electron mi-croscopy,X-ray diffraction analysis,and atomic absorption spectroscopy.Moreover,we found that amorphous TiO2 layers existing in the final samples play an important role in formation ofyolk-shell nanoparticles,which bind the as-prepared ZnxCnanoparticlescan be tuna-ble by adjusting the amount of the Cd and Zn source compounds.The photochemical reduction of Cr(Ⅵ)in water has been performed to study the photocatalytic performance under irradiation by NIR light or a simulated solar light,showing efficient photoreduction and Cr(Ⅵ)removal over the/TiO2 yolk-shell nanoparticles.The as-prepared UCNPs@ZnxC/TiO2 nanoparticles show excellent production of hydroxyl radicals,which are responsible for the photochemical reduction of Cr(Ⅵ)to Cr(Ⅲ).This study will provide an alternative strategy for en-vironmental wastewater treatment,making full use of solar energy.
基金supported in part by the National Natural Science Foundation of China(21471043,21304028,51403195,31501576)~~
文摘We report a colloidal process to coat a layer of TiO2onto SiO2composite nanofibers containing embedded CdS and upconversion nanoparticles(UCNPs).The SiO2composite nanofibers were fabricated by electrospinning.To improve the energy transfer efficiency,UCNPs and CdS nanoparticles were bound in close proximity to each other within the SiO2matrix.β‐NaYF4:Yb(30%),Tm(0.5%)@NaYF4:Yb(20%),Er(2%)core–shell nanoparticles were used as nanotransducers for near infrared light.These nanoparticles exhibited enhanced upconversion fluorescence compared withβ‐NaYF4:Yb(30%),Tm(0.5%)orβ–NaYF4:Yb(30%),Tm(0.5%)@NaYF4nanoparticles.The morphologies,size and chemical compositions have been extensively investigated using field emission scanning electron microscopy(FESEM),transmission electron microscopy(TEM),X‐ray diffraction(XRD)and X‐ray photoelectron spectra(XPS),respectively.The TEM images showed that the TiO2composite nanotubes were embedded with a large amount of UCNPs and CdS nanoparticles.The composite TiO2nanotubes degraded more than90%of rhodamine B(RhB)dye during20min of irradiation by simulated solar light.In particular,more than50%of RhB was decomposed in70min,under irradiation of near infrared light(NIR).This high degradation was attributed to the full spectrum absorption of solar light,and the enhanced transfer efficiency for near infrared light.The as‐prepared nanostructures can harness solar energy,and provide an alternative to overcome energy shortages and environmental protection.
基金Supported by the National Natural Science Foundation of China (No. 20126010).
文摘Quantitative prediction of distribution function and adhesionefficiency of particles around a rising bubble in slurry systems ispresented in this work. By solving the convection-diffusion equation(Fokker-Planck equation), the influence of Brownian diffusivity offine particles on concentration distribution and adhesion efficiencyis demonstrated with the hydrodynamic force and van der Waalsattractive potential between particles and bubble considered. It isfound that two kinds of mechanism dominate the adhesion process ofparticles on bubble according to different Peclet number or size ofparticles and bubble, as well as other properties of the slurrysystems. In addition, the viscosity ratio of bubble to the suspendingfluid was found to have obvious influence on particle adhesion.
基金supported in part by research grants from the Ministry of Education,Culture,Sports,Science and Technology of Japan and Kochi University
文摘This review examines the organizational principles underlying olfactory learning in three specialized contexts that occur during sensitive periods of enhanced neural plasticity and emphasizes some of their common features. All three forms of olfactory learning are associated with neural changes in the olfactory bulb (OB) at the first stage of sensory processing. These changes require the association of the olfactory and somatosensory signals in the OB. They all depend on somatosensory stimulation-induced release of noradrenaline that induces structural and functional changes at mitral-granule cell reciprocal synapses in the OB, resulting in increases in inhibitory transmission. In the accessory olfactory bulb, this represents the enhanced self-inhibition of mitral cells, which selectively disrupts the transmission of the mating male's pregnancy-blocking signal at this level. In contrast, an extensive network of secondary dendrites of mitral cells in the main olfactory bulb probably results in a sharpening of the odor-induced pattern of activity, due to increases in lateral inhibition, leading to offspring recognition in sheep and neonatal learning in rats and rabbits. These findings show that inhibitory intemeurons play a critical role in olfactory learning. Further work on how these neurons shape olfactory circuit function could provide important clues to understand memory functions of interneurons in other systems. Moreover, recent research has suggested that three forms of olfactory learning are controlled by synergistic, redundant, and distributed neural mechanisms. This has general implications regarding the mechanisms that may contribute to the robustness of memories [Current Zoology 56 (6): 819-833, 2010].
文摘Objective:The paper aimed to study the relationship between the expressions of immunoglobulin G(IgG) subclasses toward human papillomavirus 16-like particles(HPV16VLPs) in the serum of patients and different grades of cervical lesions.Methods:The expressions of IgG subclasses in 32 cases of human papillomavirus(HPV) infection,30 cervical intraepithelial neoplasia(CIN I),43 CIN Ⅱ-Ⅲ,and 24 hysteromyoma and chronic cervicitis were examined by ELISA.Results:The absorbance values of HPV16VLPs-IgG,IgG1 increased with the grade of CIN(P < 0.05).The IgG2 dominance(IgG2/IgG1 ratio > 1) from control group was 100%,87.50% for HPV infection group,75% for CIN I group,compared with that from CIN Ⅱ-Ⅲ patients(9.52%)(P < 0.05).The positive rates and absorbance values of HPV16VLPs-IgG,IgG1 and IgG2 from HPV16-DNA positive group were significantly higher than those from non-HPV16-DNA positive group(P < 0.05).There was a moderate correlation between the HPV16-DNA testing and detection of HPV16VLPs-IgG(r = 0.531,P < 0.05).Conclusion:An increase of the expressions of HPV16VLPs-IgG and its subclasses in the serum of the patients with cervical precancerous lesions,especially those with CIN II-III,might be associated with duration of HPV infection and severity of cervical lesions.An increase of the IgG2 dominance(IgG2/IgG1 > 1) in serum from low grade cervical lesions group and normal control group,might indicate the clearance of HPV infection and the regression of cervical lesions.
文摘Highly luminescent upconversion nanoparticles (UCNPs) with small sizes are highly desirable for bioapplications. A facile in situ cation exchange strategy has been developed to greatly enhance the UC luminescence of hexagonal phase NaYF4 NPs while maintaining their small particle size and shape. Via a cation exchange treatment by hot-injecting Gd3+ precursors into the as-prepared NPs solution without pre-separation, the naked-eye visible UC emission of the NPs was enhanced about 29 times under 980 nm near infrared (NIR) excitation with unchanged particle size. The cation exchange process was further demonstrated for the case of NaYF4 nanorods (NRs). After the cation exchange, the nanorod was broken into two NPs with stronger emission. The cation exchanged hydrophobic UCNPs were further encapSulated with poly(amino acid) and successfully applied for targeted cancer cell UC luminescence imaging.
文摘The coupling of upconversion nanophosphors (UCNPs) with the surface plasmonic resonance (SPR) of noble metals is a promising way to improve luminescent efficiency of UCNPs; however, it is still a challenge to achieve stable, reproducible and effective upconversion luminescence (UCL) enhancement through such coupling. In this work, we present a novel strategy to improve UCL of NaYF4:ybB,Er3. UCNPs, by combining the near-field coupling of SPR of silver and the far-field coupling of poly(methyl methacrylate) (PMMA) opal photonic crystals (OPCs) with the UCNPs. In order to control the effective interaction distance between the UCNPs and the SPR, a porous silver film consisting of randomly distributed silver nanoparticles (NPs) (〉 100 nm) was prepared which demonstrated strong SPR over a broad wavelength range, and its coupling to the UCNPs was found to be much stronger than that of a dense film. In the far-field coupling of OPCs, the photonic stop band (PSB) of the PMMA OPCs was tuned to 980 nm, matching exactly the excitation light. By modulating the particle size of the UCNPs, and the direction and excitation power of the incident light, a maximum enhancement of 60-fold was observed, which is an important advance for metaMnduced UCL enhancement systems.