Local hypoxia in solid tumors often results in resistance to radiotherapy （RT）, in which oxygen is an essential element for enhancing DNA damage caused by ionizing radiation. Herein, we developed gold@manganese diox...Local hypoxia in solid tumors often results in resistance to radiotherapy （RT）, in which oxygen is an essential element for enhancing DNA damage caused by ionizing radiation. Herein, we developed gold@manganese dioxide （Au@MnO2） core-shell nanoparticles with a polyethylene glycol （PEG） coating as a novel radiosensitizing agent to improve RT efficacy during cancer treatment. In this Au@MnO2 nanostructure, while the gold core is a well-known RT sensitizer that interacts with X-rays to produce charged particles for improved cancer killing under RT, the MnO2 shell may trigger the decomposition of endogenous H2O2 in the tumor microenvironment to generate oxygen and overcome hypoxiaassociated RT resistance. As demonstrated by both in vitro and in vivo experiments, Au@MnO2-PEG nanoparticles acted as effective radiosensitizers to remarkably enhance cancer treatment efficacy during RT. Moreover, no obvious side effects of Au@MnO2-PEG were observed in mice. Therefore, our work presents a new type of radiosensitizer with potential for enhanced RT treatment of hypoxic tumors.展开更多
Cold-rolled thin strip steel of high flatness quality undergoes multistage deformation during tension leveling. Thus, the parameters of set-up and manipulating are more difficult. With the aid of FE code MSC. MARC, th...Cold-rolled thin strip steel of high flatness quality undergoes multistage deformation during tension leveling. Thus, the parameters of set-up and manipulating are more difficult. With the aid of FE code MSC. MARC, the tension leveling process of thin strip steel was numerically simulated. Concentrating on the influence of the roll intermeshes in 2# anti-cambering on the distribution and magnitude of residual stresses in leveled strip steel, several experiments were clone with the tension leveler based on the results from the simulation. It was found from the simulation that the magnitude of longitudinal residual stresses in the cross-section of the leveled strip steel regularly presents obvious interdependence with the roll intermeshes in 2# anti-cambering. In addition, there is a steady zone as the longitudinal residual stresses of the surface layers in leveled strip steel vary with the roll intermeshes of 2# anticambering, which is of importance in the manipulation of tension levelers. It was also found that the distribution of strains and stresses across the width of strip steel is uneven during leveling or after removing the tension loaded upon the strip, from which it was found that 3D simulation could not be replaced by 2D analysis because 2D analysis in this case cannot represent the physical behavior of strip steel deformation during tension leveling.展开更多
Molluscan shells are fascinating examples of highly ordered hierarchical structure and complex organic-inorganic biocomposite material. However, their anti-wear properties were rarely studied especially in the perspec...Molluscan shells are fascinating examples of highly ordered hierarchical structure and complex organic-inorganic biocomposite material. However, their anti-wear properties were rarely studied especially in the perspective of biological coupling. So in the current study three typical shells, Scapharca subcrenata, Rapana venosa and Acanthochiton rubrolineatus, were selected as coupling models to further study their anti-wear properties. Stereomicroscope and scanning electron microscopic observations showed that all these three shells had specific surface morphologies and complicated section microstructures. Importantly, a special structure, pore canal tubules, was discovered in the shells of Scapharca subcrenata and Acanthochiton rubrolineatus, which probably contributed most to their anti-wear properties. X-ray diffraction and micro-Vikers hardness tester were further adopted to analyze the phase compositions and micro-hardness of the shells. The measured results demonstrated that aragonite was the most extensive phase present in the shell, and possesed a relatively high micro-hardness. In this paper, the shells were described in details in morphology, structure and material with emphasis on the relationship with anti-wear property. The study revealed that the selected seashells possess distinct anti-wear properties by complicated mechanisms involving the integrated functions of multiple biological coupling elements, and this would provide inspiration to the design of new bionic wear resistance components.展开更多
基金This work was partially supported by the National Basic Research Program of China （973 Program, Nos. 2014CB931900 and 2012CB932600）, National Natural Science Foundation of China （Nos. 81471716 and 31400861）, the National Natural Science Foundation of Jiangsu Province （No. BK20140320）, and a Project Funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions （PAPD）.
文摘Local hypoxia in solid tumors often results in resistance to radiotherapy （RT）, in which oxygen is an essential element for enhancing DNA damage caused by ionizing radiation. Herein, we developed gold@manganese dioxide （Au@MnO2） core-shell nanoparticles with a polyethylene glycol （PEG） coating as a novel radiosensitizing agent to improve RT efficacy during cancer treatment. In this Au@MnO2 nanostructure, while the gold core is a well-known RT sensitizer that interacts with X-rays to produce charged particles for improved cancer killing under RT, the MnO2 shell may trigger the decomposition of endogenous H2O2 in the tumor microenvironment to generate oxygen and overcome hypoxiaassociated RT resistance. As demonstrated by both in vitro and in vivo experiments, Au@MnO2-PEG nanoparticles acted as effective radiosensitizers to remarkably enhance cancer treatment efficacy during RT. Moreover, no obvious side effects of Au@MnO2-PEG were observed in mice. Therefore, our work presents a new type of radiosensitizer with potential for enhanced RT treatment of hypoxic tumors.
基金Item Sponsored by Korea Research Foundation (KRF-2004-005-D00111)
文摘Cold-rolled thin strip steel of high flatness quality undergoes multistage deformation during tension leveling. Thus, the parameters of set-up and manipulating are more difficult. With the aid of FE code MSC. MARC, the tension leveling process of thin strip steel was numerically simulated. Concentrating on the influence of the roll intermeshes in 2# anti-cambering on the distribution and magnitude of residual stresses in leveled strip steel, several experiments were clone with the tension leveler based on the results from the simulation. It was found from the simulation that the magnitude of longitudinal residual stresses in the cross-section of the leveled strip steel regularly presents obvious interdependence with the roll intermeshes in 2# anti-cambering. In addition, there is a steady zone as the longitudinal residual stresses of the surface layers in leveled strip steel vary with the roll intermeshes of 2# anticambering, which is of importance in the manipulation of tension levelers. It was also found that the distribution of strains and stresses across the width of strip steel is uneven during leveling or after removing the tension loaded upon the strip, from which it was found that 3D simulation could not be replaced by 2D analysis because 2D analysis in this case cannot represent the physical behavior of strip steel deformation during tension leveling.
基金supported by the National Natural Science Foundation of China (Grant No. 50635030)the Key Technologies Research and Devolpment Program of Jilin Province (Grant No. 09ZDGG001)the Postdoctoral Natural Science Foundation of China (Grant No. 20090461036)
文摘Molluscan shells are fascinating examples of highly ordered hierarchical structure and complex organic-inorganic biocomposite material. However, their anti-wear properties were rarely studied especially in the perspective of biological coupling. So in the current study three typical shells, Scapharca subcrenata, Rapana venosa and Acanthochiton rubrolineatus, were selected as coupling models to further study their anti-wear properties. Stereomicroscope and scanning electron microscopic observations showed that all these three shells had specific surface morphologies and complicated section microstructures. Importantly, a special structure, pore canal tubules, was discovered in the shells of Scapharca subcrenata and Acanthochiton rubrolineatus, which probably contributed most to their anti-wear properties. X-ray diffraction and micro-Vikers hardness tester were further adopted to analyze the phase compositions and micro-hardness of the shells. The measured results demonstrated that aragonite was the most extensive phase present in the shell, and possesed a relatively high micro-hardness. In this paper, the shells were described in details in morphology, structure and material with emphasis on the relationship with anti-wear property. The study revealed that the selected seashells possess distinct anti-wear properties by complicated mechanisms involving the integrated functions of multiple biological coupling elements, and this would provide inspiration to the design of new bionic wear resistance components.
