In order to provide a new utilization method for cadmium-contaminated rice,a preliminary study of the removal of rice starch cadmium by water,calcium hydroxide,sodium hydroxide and citric acid was conducted,the damage...In order to provide a new utilization method for cadmium-contaminated rice,a preliminary study of the removal of rice starch cadmium by water,calcium hydroxide,sodium hydroxide and citric acid was conducted,the damage degree of starch was compared by SEM,and then the recombinant rice was obtained by a twin-screw extruder using the starch which met the safety standard.The physical and chemical properties of recombinant rice were analyzed by acid hydrolysis and texture analyzer.The results showed that citric acid was a good rice cadmium removal agent.The quality of recombinant rice prepared from cadmium-removed rice starch was improved;the acid resistance was increased.Heavy metal contaminated rice can be a staple food with better quality and higher value through processing.展开更多
The stiffness and nanotopographical characteristics of the extracellular matrix (ECM) influence numerous developmental, physiological, and pathological processes in vivo. These biophysical cues have therefore been a...The stiffness and nanotopographical characteristics of the extracellular matrix (ECM) influence numerous developmental, physiological, and pathological processes in vivo. These biophysical cues have therefore been applied to modulate almost all aspects of cell behavior, from cell adhesion and spreading to proliferation and differentiation. Delineation of the biophysical modulation of cell behavior is critical to the rational design of new biomaterials, implants, and medical devices. The effects of stiffness and topographical cues on cell behavior have previously been reviewed, respectively; however, the interwoven effects of stiffness and nanotopographical cues on cell behavior have not been well described, despite similarities in phenotypic manifestations. Herein, we first review the effects of substrate stiffness and nanotopography on cell behavior, and then focus on intracellular transmission of the biophysical signals from integrins to nucleus. Attempts are made to connect extracellular regulation of cell behavior with the biophysical cues. We then discuss the challenges in dissecting the biophysical regulation of cell behavior and in translating the mechanistic understanding of these cues to tissue engineering and regenerative medicine.展开更多
Constructing a suitable heterojunction photocatalytic system from two photocatalytic materials is an efficient approach for designing extremely efficient photocatalysts for a broader range of environmental,medical,and...Constructing a suitable heterojunction photocatalytic system from two photocatalytic materials is an efficient approach for designing extremely efficient photocatalysts for a broader range of environmental,medical,and energy applications.Recently,the construction of a step-scheme heterostructure system(hereafter called the S-scheme)has received widespread attention in the photocatalytic field due to its ability to achieve efficient photogenerated carrier separation and obtain strong photo-redox ability.Herein,a novel S-scheme heterojunction system consisting of 2D O-doped g-C_(3)N_(4)(OCN)nanosheets and 3D N-doped Nb_(2)O_(5)/C(N-NBO/C)nanoflowers is constructed via ultrasonication and vigorous agitation technique followed by heat treatment for the photocatalytic degradation of Rhodamine B(RhB).Detailed characterization and decomposition behaviour of RhB showed that the fabricated material shows excellent photocatalytic efficiency and stability towards RhB photodegradation under visible-light illumination.The enhanced performance could be attributed to the following factors:fast charge transfer,highly-efficient charge separation,extended lifetime of photoinduced charge carriers,and the high redox capability of the photoinduced charges in the S-scheme system.Various trapping experiment conditions and electron paramagnetic resonance provide clear evidence of the S-scheme photogenerated charge transfer path,meanwhile,the RhB mineralization degradation pathway was also investigated using LC-MS.This study presents an approach to constructing Nb_(2)O_(5)-based S-scheme heterojunctions for photocatalytic applications.展开更多
Edible zein-based films containing lysozyme(LY) and ascorbic acid(AA) were developed in the presence of polyethylene glycol 400(PEG 400), the combined effects of LY and AA on the microstructure, mechanical properties ...Edible zein-based films containing lysozyme(LY) and ascorbic acid(AA) were developed in the presence of polyethylene glycol 400(PEG 400), the combined effects of LY and AA on the microstructure, mechanical properties and release properties of developed zein films were investigated in detail. The results of microstructure characterization indicated that zein-based films became compact and smooth, and LY aggregates were well distributed in the zein matrix because of the simultaneous addition of LY and AA. The results of mechanical tests showed that because of the synergistic effects of LY and AA on zein film, elongation at break of zein-based film could be up to 138%, which was 34.5 times higher than that of zein control film. LY release tests showed that when the concentration of AA was less than 3.1 mg·cm^(-2), the release rate of LY significantly decreased by 33.7%, and the total release increased by 80.6%. While the release profiles of AA showed that the release rate and total release of AA from the films containing LY increased by approximately 68.9% and 61.7% than the films without LY. Good antioxidant and sustained antimicrobial activities were found for the developed zein films.展开更多
Electron relaxation time and density of states near the Fermi level were calculated for "dirty" carbon nanotubes taking into account multiple elastic electrons scattering on impurities and structural inhomogeneities...Electron relaxation time and density of states near the Fermi level were calculated for "dirty" carbon nanotubes taking into account multiple elastic electrons scattering on impurities and structural inhomogeneities of a short-range order type. A possible explanation of low-temperature behavior of density of states and electrical conductivity depending on defect structure, impurities and chirality is presented.展开更多
The paper presents a study of the growth and characterization of carbon nanotube-rutile nanocomposites. The heterostructures were obtained with a chemical mixing method. Scanning electron microscope images show that t...The paper presents a study of the growth and characterization of carbon nanotube-rutile nanocomposites. The heterostructures were obtained with a chemical mixing method. Scanning electron microscope images show that the samples appear as a homogeneous powder of rutile with carbon nanotubes intercalated in interspaces between the TiO2 grains. Characterization by both X-ray photoelectron spectroscopy and cathodo-luminescence analysis show the formation of CO-Ti chemical bonds with a decrease of 0.8 eV in the band gap compared to pure rutile. The consequence of this band gap modification is a strong change in optical properties. Luminescence emission is drastically reduced and absorption in the visible range is increased of about 6% at very low concentration (1%) of carbon nanotubes.展开更多
Designing and fabricating highly efficient photocatalysts for water splitting is a promising strategy to address energy and environmental issues.Cadmium sulfide(CdS)has received significant interest as a photocatalyst...Designing and fabricating highly efficient photocatalysts for water splitting is a promising strategy to address energy and environmental issues.Cadmium sulfide(CdS)has received significant interest as a photocatalyst for visible‐light‐induced hydrogen(H2)generation.However,the severe photocorrosion,high overpotential,rapid charge recombination,and sluggish surface reaction kinetics drastically hinder its practical application in water splitting.Herein,uniform zinc cadmium sulfide(Zn_(0.5)Cd_(0.5)S)nanoparticles were anchored on ultrathin Ni(OH)_(2)nanosheets via a facile solution‐phase approach to form an intimate two‐dimensional(2D)/zero‐dimensional(0D)heterojunction.Under visible light irradiation,the 7%Ni(OH)_(2)/Zn_(0.5)Cd_(0.5)S composite exhibited the highest H2 production rate of 6.87 mmol·h^(–1)·g^(–1)with an apparent quantum yield of 16.8%at 420 nm,which is almost 43 times higher than that of pristine Zn_(0.5)Cd_(0.5)S and considerably higher than that of the Pt/Zn_(0.5)Cd_(0.5)S photocatalyst.The high photoactivity of the 2D/0D Ni(OH)_(2)/Zn_(0.5)Cd_(0.5)S heterojunction can be ascribed to its unique and robust structure,wherein the ultrathin Ni(OH)_(2)nanosheets not only provide an excellent platform for the incorporation of Zn_(0.5)Cd_(0.5)S nanoparticles but also serve as an effective cocatalyst to promote photoinduced electron transfer and offer more active sites for photocatalytic H_(2) generation.This work paves the way toward the development of versatile,low‐cost,and highly efficient 2D/0D heterojunction photocatalysts for solar energy conversion.展开更多
By a simple one-step H2-assisted thermal evaporation method, high quality CdS nanos- tructures have been successfully fabricated on Au coated Si substrates in large scale. The as-synthesized CdS nanostructures consist...By a simple one-step H2-assisted thermal evaporation method, high quality CdS nanos- tructures have been successfully fabricated on Au coated Si substrates in large scale. The as-synthesized CdS nanostructures consisted of sword-like nanobelts and toothed nanosaws with a single-crystal hexagonal wurtzite structure. The deposition temperature played an important role in determining the size and morphology of the CdS nanostruetures. A combination of vapor-liquid-solid and vapor-solid growth mechanisms were proposed to interpret the formation of CdS nanostructures. Photoluminescence measurement indicated that the nanobelts and nanosaws have a prominent green emission at about 512 nm, which is the band-to-band emission of CdS. The waveguide characteristics of both types of CdS nanos-truetures were observed and discussed.展开更多
As a new technology, Atomil Force Microscopy (AFM) is being used in the research of microscopic structure on coal surface in recent years. By this technology, we can observe the nanoscale pore and crack shape of coa...As a new technology, Atomil Force Microscopy (AFM) is being used in the research of microscopic structure on coal surface in recent years. By this technology, we can observe the nanoscale pore and crack shape of coal surface, and measure some structural parameters. Different metamorphic grades produce different feature of surface microscopic structure of coal. This paper analyzes the surface microscopic structure of different metamorphic grade coal by AFM. The results show that the coal surface microstructure has a trend from rough to smooth with the increasing of metamorphic grade. The low rank coals contain large or medium pores and the high rank coals contain micro pores. The values of surface morphology characteristic parameters (Sq and Sa) nonlinearly decrease with the increasing coal rank. That is, the coal surface becomes smoother during coalification.展开更多
Lipid nanoparticles have become attractive for its prominent properties recent years. In this paper, in vivo anti-tumor efficacy of nanostructured lipid carrier of dihydroartemisinin (DHA-NLC) were evaluated in sarc...Lipid nanoparticles have become attractive for its prominent properties recent years. In this paper, in vivo anti-tumor efficacy of nanostructured lipid carrier of dihydroartemisinin (DHA-NLC) were evaluated in sarcoma 180-bearing mice model through intraperitoneal (i.p.) administration. In vivo biodistribution was also investigated in Kunming mice bearing S180. Results demonstrated that the intraperitoneally injected DHA-NLC could significantly inhibit tumor growth at the dose levels of 20, 40 and 80 mg/kg, and their inhibition rates were 71.24%, 79.20% and 85.74%, respectively. The biodistribution of DHA after intraperitoneal injection of DHA-NLC in S180-bearing mice is remarkably different from the DHA solution. Therefore, DHA encapsulated in NLC does demonstrate superior anticancer effect to DHA suspension on S 180-bearing mice at the same dose and displayed a dose-dependent antitumor efficacy.展开更多
Artemisinin(ART) is a widely used active drug for malaria, including severe and cerebral malaria. However, its therapeutic efficacy is affected by its lower bioavailability. In the present study, nanostructured lipi...Artemisinin(ART) is a widely used active drug for malaria, including severe and cerebral malaria. However, its therapeutic efficacy is affected by its lower bioavailability. In the present study, nanostructured lipid carriers(NLCs) were proposed as carrier of ART to improve pharmacokinetic properties of the drug. ART-NLC was prepared by high-pressure homogenization based on orthogonal design. The particle size, zeta potential, encapsulation efficiency(EE) and percentage of drug loading(DL) of ART-NLC were(53.06±2.11) nm,(–28.7±3.59) m V, 73.9%±0.5% and 11.23%±0.37%, respectively. ART-NLC showed the sustained release characteristics and scarcely the hemolysis effect on human red blood cells. The pharmacokinetics of ART-NLC for rats after tail intravenous injection(i.v) or intraperitoneal injection(i.p) were investigated by liquid chromatography-tandem mass spectroscopy(LC-MS/MS). And ART solution was designed as control preparation. For rats of i.v groups, the AUC0–∞((707.45±145.65) ng·h/m L) of ART-NLC were significantly bigger than that of ART((368.98±139.58) ng·h/m L). The MRT((3.38±0.46) h) of ART-NLC was longer than that of ART((1.39±0.61) h). And similar results were observed for rats of i.p groups. The AUC0–∞((1233.06±235.57) ng·h/m L) and MRT((4.97±0.69) h) of ART-NLC were both bigger than those of ART, which were(871.17±234.03) ng·h/m L) and(1.75±0.31) h), respectively. Compared with ART, ART-NLC showed a significant increase in AUC0–∞(P〈0.05) and MRT(P〈0.001) for both i.p and tail i.v administrations.展开更多
To reduce the problems of poor solubility,high in vivo dosage requirement,and weak targeting ability of paclitaxel(PTX),a hyaluronic acid-octadecylamine(HA-ODA)-modified nano-structured lipid carrier(HA-NLC)was constr...To reduce the problems of poor solubility,high in vivo dosage requirement,and weak targeting ability of paclitaxel(PTX),a hyaluronic acid-octadecylamine(HA-ODA)-modified nano-structured lipid carrier(HA-NLC)was constructed.HA-ODA conjugates were synthesized by an amide reaction between HA and ODA.The hydrophobic chain of HA-ODA can be embedded in the lipid core of the NLC to obtain HA-NLC.The HA-NLC displayed strong internalization in cluster determinant 44(CD44)highly expressed MCF-7 cells,and endocytosis mediated by the CD44 receptor was involved.The HA-NLC had an encapsulation efficiency of PTX of 72.0%.The cytotoxicity of the PTXloaded nanoparticle HA-NLC/PTX in MCF-7 cells was much stronger than that of the commercial preparation Taxol.In vivo,the HA-NLC exhibited strong tumor targeting ability.The distribution of the NLCs to the liver and spleen was reduced after HA modification,while more nanoparticles were aggregated to the tumor site.Our results suggest that HA-NLC has excellent properties as a nano drug carrier and potential for in vivo targeting.展开更多
A facile strategy was designed for the fabrication of Fe3O4-nanoparticle- decorated TiO2 nanofiber hierarchical heterostructures (FTHs) by combining the versatility of the electrospinning technique and the hydrother...A facile strategy was designed for the fabrication of Fe3O4-nanoparticle- decorated TiO2 nanofiber hierarchical heterostructures (FTHs) by combining the versatility of the electrospinning technique and the hydrothermal growth method. The hierarchical architecture of Fe3O4 nanoparticles decorated on TiO2 nanofibers enables the successful integration of the binary composite into batteries to address structural stability and low capacity. In the resulting unique architecture of FTHs, the 1D heterostructures relieve the strain caused by severe volume changes of Fe3O4 during numerous charge-discharge cycles, and thus suppress the degradation of the electrode material. As a result, FTHs show excellent performance including higher reversible capacity, excellent cycle life, and good rate performance over a wide temperature range owing to the synergistic effect of the binary composition of TiO2 and Fe304 and the unique features of the hierarchical nanofibers.展开更多
The spindle-like, tubular, and tire-like hematite were successively fabricated by a facile, one-step hydrothermal procedure, which is of great importance in facilitating the controllable-synthesis process of commercia...The spindle-like, tubular, and tire-like hematite were successively fabricated by a facile, one-step hydrothermal procedure, which is of great importance in facilitating the controllable-synthesis process of commercial industrialization. A mechanism involving a formation-dissolution process was proposed based on the X-ray diffraction, scanning electron microscopy, trans-mission electron microscopy, and high-resolution transmission electron microscopy analysis. It was demonstrated that the presence of phosphate ions during the reaction process is crucial to the morphology evolution of hematite. Their different ad-sorption ability on the different crystallographic planes of hematite and a coordination effect with ferric ions could promote the preferential dissolution of the spindle-like hematite precursors along the long axis [001] from the tips down to the interior, and thus yield the tubular and tire-like hematite one by one with the increasing reaction time. The magnetic measurements have also been performed to investigate the different magnetic properties such as coercivity and low-temperature transition behavior of three different hematite nanostructures.展开更多
Monodisperse and size-tunable magnetic iron oxide nanoparticles (NPs) have been synthesized by thermal decomposition of an iron oleate complex at 310 ℃ in the presence of oleylamine and oleic acid. The diameters of...Monodisperse and size-tunable magnetic iron oxide nanoparticles (NPs) have been synthesized by thermal decomposition of an iron oleate complex at 310 ℃ in the presence of oleylamine and oleic acid. The diameters of the as-synthesized iron oxide NPs decrease with increasing concentrations of iron oleate complex and oleic acid/oleylamine. In addition, the size-dependent crystallinity and magnetic properties of iron oxide NPs are presented. It is found that larger iron oxide NPs have a higher degree of crystallinity and saturation magnetization. More importantly, various M-iron oxide heterostructures (M = Au, Ag, Pt, Pd) have been successfully fabricated by using the same synthesis procedure. The iron oxide NPs are grown over the pre-made metal seeds through a seed-mediated growth process. The physicochemical properties of Au-Fe3O4 heterostructures have been characterized by X-ray diffraction (XRD), superconducting quantum interference device (SQUID) magnetometry and UV-vis spectroscopy. The as-synthesized Au-Fe3O4 heterostructures show a red-shift in surface plasmon resonance peak compared with Au NPs and similar magnetic properties to Fe3O4 NPs. The heterojunction effects present in such nanostructures offer the opportunity to tune the irphysicochemical properties. Therefore, this synthesis process can be regarded as an efficient way to fabricate a series of heterostructures for a variety of applications.展开更多
Developing highly efficient,cost-effective,and stable electrocatalysts for hydrogen evolution reaction(HER)is of considerable importance but remains challenging.Herein,we report the fabrication of a robust Ru-based el...Developing highly efficient,cost-effective,and stable electrocatalysts for hydrogen evolution reaction(HER)is of considerable importance but remains challenging.Herein,we report the fabrication of a robust Ru-based electrocatalyst,which comprises heterostructured Ru-Ru_(2)P nanoparticles that are embedded in the N,P-codoped carbon nanofibers(CNFs),through a synthetic strategy involving electrospinning and temperature-controlled pyrolysis treatment.The as-prepared Ru-Ru_(2)P catalyst(Ru-Ru_(2)P@CNFs)shows excellent HER catalytic activities with low overpotentials of 11 and 14 mV in acidic and alkaline media,respectively,to achieve a current density of 10 mA cm^(−2),which are superior to the individual components of pure Ru and Ru_(2)P catalysts.Density functional theory calculations demonstrate the existence of electronic coupling effect between Ru and Ru_(2)P at the heterointerfaces,leading to a well-modulated electronic structure with optimized hydrogen adsorption strength and enhanced electrical conductivity for efficient HER electrocatalysis.In addition,the overall synthetic strategy can be generalized for the synthesis of a series of transitional metal phosphide-based nanofibers,thereby holding a remarkable capacity for various potential applications.展开更多
We report the direct synthesis of ZnC0204 and ZnO/ZnC0204 submicron rod arrays grown on Ni foil current collectors via an ammonia-evaporation-induced method by controlling the ratio of Zn to Co. These three-dimension...We report the direct synthesis of ZnC0204 and ZnO/ZnC0204 submicron rod arrays grown on Ni foil current collectors via an ammonia-evaporation-induced method by controlling the ratio of Zn to Co. These three-dimensional (3D) hierar- chical self-supported nanostructures are composed of one-dimensional (1D) ZnCo204 rods and two-dimensional (2D) ZnO nanosheet bands perpendicular to the axis of the each ZnCo204 rod. We carefully deal with the heteroepitaxial growth mechanisms of hexagonal ZnO nanosheets from a crystallographic point of view. Furthermore, we demonstrate the ability of these high-surface-area ZnO/ZnCo204 heterostructured rods to enable improved electrolyte permeability and Li ion transfer, thereby enhancing their Li storage capability (-900 mA.h.g-1 at a rate of 45 mA.h.g-1) for Li ion battery electrodes.展开更多
This paper reviews the recent research progress in the hetero-nanostructure of silver nanoparticles on MOx (M=Mo, Ti and Si). It describes the general synthesis of hetero-nanostructure of silver nanoparticles on MOx, ...This paper reviews the recent research progress in the hetero-nanostructure of silver nanoparticles on MOx (M=Mo, Ti and Si). It describes the general synthesis of hetero-nanostructure of silver nanoparticles on MOx, and then outlines the interesting catalytic and sensing properties found in these hetero-nanostructures of silver nanoparticles on MOx.展开更多
In this report we explore the structural and optical properties of GaAs/A1GaAs heterostructure nanowires grown by metalorganic vapour phase epitaxy using gold seed-particles. The optical studies were done by low-tempe...In this report we explore the structural and optical properties of GaAs/A1GaAs heterostructure nanowires grown by metalorganic vapour phase epitaxy using gold seed-particles. The optical studies were done by low-temperature cathodo- luminescence (CL) in a scanning electron microscope (SEM). We perform a systematic investigation of how the nanowire growth-temperature affects the total photon emission, and variations in the emission energy and intensity along the length of the nanowires. The morphology and crystal structures of the nanowires were investigated using SEM and transmission electron microscopy (TEM). In order to correlate specific photon emission characteristics with variations in the nanowire crystal structure directly, TEM and spatially resolved CL measurements were performed on the same individual nanowires. We found that the main emission energy was located at around 1.48 eV, and that the emission intensity was greatly enhanced when increasing the GaAs nanowire core growth temperature. The data strongly suggests that this emission energy is related to rotational twins in the GaAs nanowire core. Our measurements also show that radial overgrowth by GaAs on the GaAs nanowire core can have a deteriorating effect on the optical quality of the nanowires. Finally, we conclude that an in situ pre-growth annealing step at a sufficiently high temperature significantly improves the optical quality of the nanowires.展开更多
文摘In order to provide a new utilization method for cadmium-contaminated rice,a preliminary study of the removal of rice starch cadmium by water,calcium hydroxide,sodium hydroxide and citric acid was conducted,the damage degree of starch was compared by SEM,and then the recombinant rice was obtained by a twin-screw extruder using the starch which met the safety standard.The physical and chemical properties of recombinant rice were analyzed by acid hydrolysis and texture analyzer.The results showed that citric acid was a good rice cadmium removal agent.The quality of recombinant rice prepared from cadmium-removed rice starch was improved;the acid resistance was increased.Heavy metal contaminated rice can be a staple food with better quality and higher value through processing.
基金The authors would like to acknowledge funding support for Yong Yang from the National Science Foundation (CBET 1511759) and the National Institute of Health (NIH) (R15GM122953), and for Kam W. Leong from NIH (HL109442, AI096305, GMl10494, and UH3 TR000505), Guangdong Innovative and Entrepreneurial Research Team Program (2013S086), and the Global Research Laboratory Program (Korean NSF GRL 2015032163).
文摘The stiffness and nanotopographical characteristics of the extracellular matrix (ECM) influence numerous developmental, physiological, and pathological processes in vivo. These biophysical cues have therefore been applied to modulate almost all aspects of cell behavior, from cell adhesion and spreading to proliferation and differentiation. Delineation of the biophysical modulation of cell behavior is critical to the rational design of new biomaterials, implants, and medical devices. The effects of stiffness and topographical cues on cell behavior have previously been reviewed, respectively; however, the interwoven effects of stiffness and nanotopographical cues on cell behavior have not been well described, despite similarities in phenotypic manifestations. Herein, we first review the effects of substrate stiffness and nanotopography on cell behavior, and then focus on intracellular transmission of the biophysical signals from integrins to nucleus. Attempts are made to connect extracellular regulation of cell behavior with the biophysical cues. We then discuss the challenges in dissecting the biophysical regulation of cell behavior and in translating the mechanistic understanding of these cues to tissue engineering and regenerative medicine.
文摘Constructing a suitable heterojunction photocatalytic system from two photocatalytic materials is an efficient approach for designing extremely efficient photocatalysts for a broader range of environmental,medical,and energy applications.Recently,the construction of a step-scheme heterostructure system(hereafter called the S-scheme)has received widespread attention in the photocatalytic field due to its ability to achieve efficient photogenerated carrier separation and obtain strong photo-redox ability.Herein,a novel S-scheme heterojunction system consisting of 2D O-doped g-C_(3)N_(4)(OCN)nanosheets and 3D N-doped Nb_(2)O_(5)/C(N-NBO/C)nanoflowers is constructed via ultrasonication and vigorous agitation technique followed by heat treatment for the photocatalytic degradation of Rhodamine B(RhB).Detailed characterization and decomposition behaviour of RhB showed that the fabricated material shows excellent photocatalytic efficiency and stability towards RhB photodegradation under visible-light illumination.The enhanced performance could be attributed to the following factors:fast charge transfer,highly-efficient charge separation,extended lifetime of photoinduced charge carriers,and the high redox capability of the photoinduced charges in the S-scheme system.Various trapping experiment conditions and electron paramagnetic resonance provide clear evidence of the S-scheme photogenerated charge transfer path,meanwhile,the RhB mineralization degradation pathway was also investigated using LC-MS.This study presents an approach to constructing Nb_(2)O_(5)-based S-scheme heterojunctions for photocatalytic applications.
基金Supported by the National Natural Science Foundation of China(21476086)Guangdong Natural Science Foundation(2014A030312007)
文摘Edible zein-based films containing lysozyme(LY) and ascorbic acid(AA) were developed in the presence of polyethylene glycol 400(PEG 400), the combined effects of LY and AA on the microstructure, mechanical properties and release properties of developed zein films were investigated in detail. The results of microstructure characterization indicated that zein-based films became compact and smooth, and LY aggregates were well distributed in the zein matrix because of the simultaneous addition of LY and AA. The results of mechanical tests showed that because of the synergistic effects of LY and AA on zein film, elongation at break of zein-based film could be up to 138%, which was 34.5 times higher than that of zein control film. LY release tests showed that when the concentration of AA was less than 3.1 mg·cm^(-2), the release rate of LY significantly decreased by 33.7%, and the total release increased by 80.6%. While the release profiles of AA showed that the release rate and total release of AA from the films containing LY increased by approximately 68.9% and 61.7% than the films without LY. Good antioxidant and sustained antimicrobial activities were found for the developed zein films.
文摘Electron relaxation time and density of states near the Fermi level were calculated for "dirty" carbon nanotubes taking into account multiple elastic electrons scattering on impurities and structural inhomogeneities of a short-range order type. A possible explanation of low-temperature behavior of density of states and electrical conductivity depending on defect structure, impurities and chirality is presented.
文摘The paper presents a study of the growth and characterization of carbon nanotube-rutile nanocomposites. The heterostructures were obtained with a chemical mixing method. Scanning electron microscope images show that the samples appear as a homogeneous powder of rutile with carbon nanotubes intercalated in interspaces between the TiO2 grains. Characterization by both X-ray photoelectron spectroscopy and cathodo-luminescence analysis show the formation of CO-Ti chemical bonds with a decrease of 0.8 eV in the band gap compared to pure rutile. The consequence of this band gap modification is a strong change in optical properties. Luminescence emission is drastically reduced and absorption in the visible range is increased of about 6% at very low concentration (1%) of carbon nanotubes.
文摘Designing and fabricating highly efficient photocatalysts for water splitting is a promising strategy to address energy and environmental issues.Cadmium sulfide(CdS)has received significant interest as a photocatalyst for visible‐light‐induced hydrogen(H2)generation.However,the severe photocorrosion,high overpotential,rapid charge recombination,and sluggish surface reaction kinetics drastically hinder its practical application in water splitting.Herein,uniform zinc cadmium sulfide(Zn_(0.5)Cd_(0.5)S)nanoparticles were anchored on ultrathin Ni(OH)_(2)nanosheets via a facile solution‐phase approach to form an intimate two‐dimensional(2D)/zero‐dimensional(0D)heterojunction.Under visible light irradiation,the 7%Ni(OH)_(2)/Zn_(0.5)Cd_(0.5)S composite exhibited the highest H2 production rate of 6.87 mmol·h^(–1)·g^(–1)with an apparent quantum yield of 16.8%at 420 nm,which is almost 43 times higher than that of pristine Zn_(0.5)Cd_(0.5)S and considerably higher than that of the Pt/Zn_(0.5)Cd_(0.5)S photocatalyst.The high photoactivity of the 2D/0D Ni(OH)_(2)/Zn_(0.5)Cd_(0.5)S heterojunction can be ascribed to its unique and robust structure,wherein the ultrathin Ni(OH)_(2)nanosheets not only provide an excellent platform for the incorporation of Zn_(0.5)Cd_(0.5)S nanoparticles but also serve as an effective cocatalyst to promote photoinduced electron transfer and offer more active sites for photocatalytic H_(2) generation.This work paves the way toward the development of versatile,low‐cost,and highly efficient 2D/0D heterojunction photocatalysts for solar energy conversion.
文摘By a simple one-step H2-assisted thermal evaporation method, high quality CdS nanos- tructures have been successfully fabricated on Au coated Si substrates in large scale. The as-synthesized CdS nanostructures consisted of sword-like nanobelts and toothed nanosaws with a single-crystal hexagonal wurtzite structure. The deposition temperature played an important role in determining the size and morphology of the CdS nanostruetures. A combination of vapor-liquid-solid and vapor-solid growth mechanisms were proposed to interpret the formation of CdS nanostructures. Photoluminescence measurement indicated that the nanobelts and nanosaws have a prominent green emission at about 512 nm, which is the band-to-band emission of CdS. The waveguide characteristics of both types of CdS nanos-truetures were observed and discussed.
基金Supported by the National Natural Science Foundation of China (41072153) the “Strategic Priority Research Program-Climate Change: Carbon Budget and Related Issues” of the Chinese Academy of Sciences (XDA05030100) the Foundation for University Key Teacher by Education Department of Henan Province (2009GGJS-038).
文摘As a new technology, Atomil Force Microscopy (AFM) is being used in the research of microscopic structure on coal surface in recent years. By this technology, we can observe the nanoscale pore and crack shape of coal surface, and measure some structural parameters. Different metamorphic grades produce different feature of surface microscopic structure of coal. This paper analyzes the surface microscopic structure of different metamorphic grade coal by AFM. The results show that the coal surface microstructure has a trend from rough to smooth with the increasing of metamorphic grade. The low rank coals contain large or medium pores and the high rank coals contain micro pores. The values of surface morphology characteristic parameters (Sq and Sa) nonlinearly decrease with the increasing coal rank. That is, the coal surface becomes smoother during coalification.
基金Fundamental Research Funds of Lanzhou University for the Central Universities (Grant No. lzujbky-2012-85)the Lanzhou Science and Technology Bureau (Grant No. 2012-2-80)
文摘Lipid nanoparticles have become attractive for its prominent properties recent years. In this paper, in vivo anti-tumor efficacy of nanostructured lipid carrier of dihydroartemisinin (DHA-NLC) were evaluated in sarcoma 180-bearing mice model through intraperitoneal (i.p.) administration. In vivo biodistribution was also investigated in Kunming mice bearing S180. Results demonstrated that the intraperitoneally injected DHA-NLC could significantly inhibit tumor growth at the dose levels of 20, 40 and 80 mg/kg, and their inhibition rates were 71.24%, 79.20% and 85.74%, respectively. The biodistribution of DHA after intraperitoneal injection of DHA-NLC in S180-bearing mice is remarkably different from the DHA solution. Therefore, DHA encapsulated in NLC does demonstrate superior anticancer effect to DHA suspension on S 180-bearing mice at the same dose and displayed a dose-dependent antitumor efficacy.
基金National Natural Science Foundation of China(Grant No.81373364)The Subject clots Project Serving Pharmaceutical Industrial Innovation of Shanxi Province
文摘Artemisinin(ART) is a widely used active drug for malaria, including severe and cerebral malaria. However, its therapeutic efficacy is affected by its lower bioavailability. In the present study, nanostructured lipid carriers(NLCs) were proposed as carrier of ART to improve pharmacokinetic properties of the drug. ART-NLC was prepared by high-pressure homogenization based on orthogonal design. The particle size, zeta potential, encapsulation efficiency(EE) and percentage of drug loading(DL) of ART-NLC were(53.06±2.11) nm,(–28.7±3.59) m V, 73.9%±0.5% and 11.23%±0.37%, respectively. ART-NLC showed the sustained release characteristics and scarcely the hemolysis effect on human red blood cells. The pharmacokinetics of ART-NLC for rats after tail intravenous injection(i.v) or intraperitoneal injection(i.p) were investigated by liquid chromatography-tandem mass spectroscopy(LC-MS/MS). And ART solution was designed as control preparation. For rats of i.v groups, the AUC0–∞((707.45±145.65) ng·h/m L) of ART-NLC were significantly bigger than that of ART((368.98±139.58) ng·h/m L). The MRT((3.38±0.46) h) of ART-NLC was longer than that of ART((1.39±0.61) h). And similar results were observed for rats of i.p groups. The AUC0–∞((1233.06±235.57) ng·h/m L) and MRT((4.97±0.69) h) of ART-NLC were both bigger than those of ART, which were(871.17±234.03) ng·h/m L) and(1.75±0.31) h), respectively. Compared with ART, ART-NLC showed a significant increase in AUC0–∞(P〈0.05) and MRT(P〈0.001) for both i.p and tail i.v administrations.
基金Project supported by the Zhejiang Provincial Natural Science Foundation of China(No.LY14H160016)。
文摘To reduce the problems of poor solubility,high in vivo dosage requirement,and weak targeting ability of paclitaxel(PTX),a hyaluronic acid-octadecylamine(HA-ODA)-modified nano-structured lipid carrier(HA-NLC)was constructed.HA-ODA conjugates were synthesized by an amide reaction between HA and ODA.The hydrophobic chain of HA-ODA can be embedded in the lipid core of the NLC to obtain HA-NLC.The HA-NLC displayed strong internalization in cluster determinant 44(CD44)highly expressed MCF-7 cells,and endocytosis mediated by the CD44 receptor was involved.The HA-NLC had an encapsulation efficiency of PTX of 72.0%.The cytotoxicity of the PTXloaded nanoparticle HA-NLC/PTX in MCF-7 cells was much stronger than that of the commercial preparation Taxol.In vivo,the HA-NLC exhibited strong tumor targeting ability.The distribution of the NLCs to the liver and spleen was reduced after HA modification,while more nanoparticles were aggregated to the tumor site.Our results suggest that HA-NLC has excellent properties as a nano drug carrier and potential for in vivo targeting.
基金This work is financially supported by the fundamental research funds for the central universities, the National Natural Science Foundation of China (Grant Nos. 51372007 and 21301014).
文摘A facile strategy was designed for the fabrication of Fe3O4-nanoparticle- decorated TiO2 nanofiber hierarchical heterostructures (FTHs) by combining the versatility of the electrospinning technique and the hydrothermal growth method. The hierarchical architecture of Fe3O4 nanoparticles decorated on TiO2 nanofibers enables the successful integration of the binary composite into batteries to address structural stability and low capacity. In the resulting unique architecture of FTHs, the 1D heterostructures relieve the strain caused by severe volume changes of Fe3O4 during numerous charge-discharge cycles, and thus suppress the degradation of the electrode material. As a result, FTHs show excellent performance including higher reversible capacity, excellent cycle life, and good rate performance over a wide temperature range owing to the synergistic effect of the binary composition of TiO2 and Fe304 and the unique features of the hierarchical nanofibers.
基金supported by the National Natural Science Foundation of China (51072086)
文摘The spindle-like, tubular, and tire-like hematite were successively fabricated by a facile, one-step hydrothermal procedure, which is of great importance in facilitating the controllable-synthesis process of commercial industrialization. A mechanism involving a formation-dissolution process was proposed based on the X-ray diffraction, scanning electron microscopy, trans-mission electron microscopy, and high-resolution transmission electron microscopy analysis. It was demonstrated that the presence of phosphate ions during the reaction process is crucial to the morphology evolution of hematite. Their different ad-sorption ability on the different crystallographic planes of hematite and a coordination effect with ferric ions could promote the preferential dissolution of the spindle-like hematite precursors along the long axis [001] from the tips down to the interior, and thus yield the tubular and tire-like hematite one by one with the increasing reaction time. The magnetic measurements have also been performed to investigate the different magnetic properties such as coercivity and low-temperature transition behavior of three different hematite nanostructures.
文摘Monodisperse and size-tunable magnetic iron oxide nanoparticles (NPs) have been synthesized by thermal decomposition of an iron oleate complex at 310 ℃ in the presence of oleylamine and oleic acid. The diameters of the as-synthesized iron oxide NPs decrease with increasing concentrations of iron oleate complex and oleic acid/oleylamine. In addition, the size-dependent crystallinity and magnetic properties of iron oxide NPs are presented. It is found that larger iron oxide NPs have a higher degree of crystallinity and saturation magnetization. More importantly, various M-iron oxide heterostructures (M = Au, Ag, Pt, Pd) have been successfully fabricated by using the same synthesis procedure. The iron oxide NPs are grown over the pre-made metal seeds through a seed-mediated growth process. The physicochemical properties of Au-Fe3O4 heterostructures have been characterized by X-ray diffraction (XRD), superconducting quantum interference device (SQUID) magnetometry and UV-vis spectroscopy. The as-synthesized Au-Fe3O4 heterostructures show a red-shift in surface plasmon resonance peak compared with Au NPs and similar magnetic properties to Fe3O4 NPs. The heterojunction effects present in such nanostructures offer the opportunity to tune the irphysicochemical properties. Therefore, this synthesis process can be regarded as an efficient way to fabricate a series of heterostructures for a variety of applications.
基金financially supported by the Natural Science Foundation of Zhejiang Province (LQ20B030001 and LY20E020002)China Postdoctoral Science Foundation (2021M702305)。
文摘Developing highly efficient,cost-effective,and stable electrocatalysts for hydrogen evolution reaction(HER)is of considerable importance but remains challenging.Herein,we report the fabrication of a robust Ru-based electrocatalyst,which comprises heterostructured Ru-Ru_(2)P nanoparticles that are embedded in the N,P-codoped carbon nanofibers(CNFs),through a synthetic strategy involving electrospinning and temperature-controlled pyrolysis treatment.The as-prepared Ru-Ru_(2)P catalyst(Ru-Ru_(2)P@CNFs)shows excellent HER catalytic activities with low overpotentials of 11 and 14 mV in acidic and alkaline media,respectively,to achieve a current density of 10 mA cm^(−2),which are superior to the individual components of pure Ru and Ru_(2)P catalysts.Density functional theory calculations demonstrate the existence of electronic coupling effect between Ru and Ru_(2)P at the heterointerfaces,leading to a well-modulated electronic structure with optimized hydrogen adsorption strength and enhanced electrical conductivity for efficient HER electrocatalysis.In addition,the overall synthetic strategy can be generalized for the synthesis of a series of transitional metal phosphide-based nanofibers,thereby holding a remarkable capacity for various potential applications.
文摘We report the direct synthesis of ZnC0204 and ZnO/ZnC0204 submicron rod arrays grown on Ni foil current collectors via an ammonia-evaporation-induced method by controlling the ratio of Zn to Co. These three-dimensional (3D) hierar- chical self-supported nanostructures are composed of one-dimensional (1D) ZnCo204 rods and two-dimensional (2D) ZnO nanosheet bands perpendicular to the axis of the each ZnCo204 rod. We carefully deal with the heteroepitaxial growth mechanisms of hexagonal ZnO nanosheets from a crystallographic point of view. Furthermore, we demonstrate the ability of these high-surface-area ZnO/ZnCo204 heterostructured rods to enable improved electrolyte permeability and Li ion transfer, thereby enhancing their Li storage capability (-900 mA.h.g-1 at a rate of 45 mA.h.g-1) for Li ion battery electrodes.
基金supported by the National Natural Science Foundation of China (50972130, 20701033, 50772100 & 10874153)Qianjiang Talent Program of Zhejiang Province (QJD1002001)+1 种基金China Postdoctoral Science Foundation (201003048 & 20090450292)Open Project Program of State Key Laboratory of Inorganic Synthesis and Preparative Chemistry, Jilin University
文摘This paper reviews the recent research progress in the hetero-nanostructure of silver nanoparticles on MOx (M=Mo, Ti and Si). It describes the general synthesis of hetero-nanostructure of silver nanoparticles on MOx, and then outlines the interesting catalytic and sensing properties found in these hetero-nanostructures of silver nanoparticles on MOx.
文摘In this report we explore the structural and optical properties of GaAs/A1GaAs heterostructure nanowires grown by metalorganic vapour phase epitaxy using gold seed-particles. The optical studies were done by low-temperature cathodo- luminescence (CL) in a scanning electron microscope (SEM). We perform a systematic investigation of how the nanowire growth-temperature affects the total photon emission, and variations in the emission energy and intensity along the length of the nanowires. The morphology and crystal structures of the nanowires were investigated using SEM and transmission electron microscopy (TEM). In order to correlate specific photon emission characteristics with variations in the nanowire crystal structure directly, TEM and spatially resolved CL measurements were performed on the same individual nanowires. We found that the main emission energy was located at around 1.48 eV, and that the emission intensity was greatly enhanced when increasing the GaAs nanowire core growth temperature. The data strongly suggests that this emission energy is related to rotational twins in the GaAs nanowire core. Our measurements also show that radial overgrowth by GaAs on the GaAs nanowire core can have a deteriorating effect on the optical quality of the nanowires. Finally, we conclude that an in situ pre-growth annealing step at a sufficiently high temperature significantly improves the optical quality of the nanowires.