Antimicrobial material is highly desired because of the increasing demand in biomedical application to prevent from the formation of biofilm.A common strategy for enhancing the antibacterial property of a metal materi...Antimicrobial material is highly desired because of the increasing demand in biomedical application to prevent from the formation of biofilm.A common strategy for enhancing the antibacterial property of a metal material is to incorporate toxic metal such as Cu and Ag.However,the reported Cu^(2+)or Ag~+released concentration from antibacterial alloys was much less than the reported minimum inhibitory ion concentrations(MIC),revealing the existence of an unknown alternative antimicrobial mechanism not relying on the toxicity of the metal ions.Herein,we proposed a new antibacterial mechanism that the antibacterial effectiveness of the different alloys is proportional to the micro-area potential differences(MAPDs)on the surface of the alloys.We designed three kinds of Ti-M(M=Zr,Ta and Au)alloys to eliminate the potential antibacterial contribution from Cu and Ag ion.We demonstrated that high MAPDs are associated with great production of reactive oxygen species(ROS),resulting in the killing effect to the biofilm known to be associated with implant infections(Staphlococcus aureus and Escherichia coli).These results provide new insights for the design of antibacterial alloys.展开更多
To elaborate soil moisture and grain size characteristics of 3 typical micro-areas in Minqin oasis-desert ecotone,samples were collected in runoff generation area and accumulated area using soil profile and multi-poin...To elaborate soil moisture and grain size characteristics of 3 typical micro-areas in Minqin oasis-desert ecotone,samples were collected in runoff generation area and accumulated area using soil profile and multi-point sampling method,for soil moisture and physicochemical property analysis. Research results that( i) water accumulation trace of accumulated area is significant and the vegetation coverage is larger than the runoff generation area. The crust development in clay sand barrier + Haloxylon ammodendron forest accumulated is better than runoff generation area,while the situation is contrary in Nitraria tangutorum sand dune lowland and clay flat land.( ii) Moisture of accumulated area in fixed Nitraria tangutorum sand inter-dune lowland is better than the runoff generation area; the moisture of accumulated area in clay flat land topsoil is significantly better than the runoff generation area,while the topsoil moisture of clay sand barrier + Haloxylon ammodendron forest is better in the runoff generation area than in the accumulated area.( iii) Soil moisture of accumulated area in 3 types of micro-areas is in the range of 20- 40 cm; the fixed Nitraria tangutorum sand inter-dune lowland is better than clay flat land and clay sand barrier + Haloxylon ammodendron forest,while the lowest moisture of corresponding runoff generation area is basically consistent with the depth.( iv) The topsoil clay and powder content in accumulated area of fixed Nitraria tangutorum sand inter-dune lowland is lower than the runoff generation area,while the fine sand content in deep layer of runoff generation area is greater than the accumulated area; soil in two areas of clay flat land mainly consists of coarse and fine sand,and clay particles are better in runoff generation area than in accumulated area. Soil in the clay sand barrier + Haloxylon ammodendron forest is mainly coarse sand and the structure is single. In sum,through adjusting allocation of rainfall,micro-areas influence soil moisture and grain size distribution,and further influence spatial- temporal distribution of vegetation in sand micro-areas.展开更多
The formation of protective rust layer of atmospheric corrosion resistance was discussed for weathering steel. The rust layers of experimental steels were made by using an accelerating industrial atmospheric corrosion...The formation of protective rust layer of atmospheric corrosion resistance was discussed for weathering steel. The rust layers of experimental steels were made by using an accelerating industrial atmospheric corrosion test of dry-wet cyclic immersion. Furthermore XRD were used to measure and analyze the rust layers. The initial corrosion processes below thin water film were observed and the changes of micro-area pH value were measured. The results are as follows： The corrosion processes of P-RE weathering steel are obviously different from those of carbon steel. The surface of P-RE weathering steel rapidly forms a-FeOOH and the micro-area pH value is above 5.4 during the initial corrosion period. While the component of the rust layer for the carbon steel is mainly Fe3O4 and the microarea pH value is below 3.8.展开更多
The basic granulite, which is considered to be the MORB based on geochemistry and isotopic characteristics[1], has been discovered recently as the enclaves in the Yingjiang island-arc magmatic suite on the border of B...The basic granulite, which is considered to be the MORB based on geochemistry and isotopic characteristics[1], has been discovered recently as the enclaves in the Yingjiang island-arc magmatic suite on the border of Burma and west Yunnan, east of Myitkyina suture in the eastern Burma. The laser micro-area 40Ar-39Ar technique is used to date the age of garnet展开更多
基金the financial support from National Natural Science Foundation of China(Nos.81071262/H1820 and 31971253/C1002)the instrumental analysis from Analytical and Testing Center,Northeastern University。
文摘Antimicrobial material is highly desired because of the increasing demand in biomedical application to prevent from the formation of biofilm.A common strategy for enhancing the antibacterial property of a metal material is to incorporate toxic metal such as Cu and Ag.However,the reported Cu^(2+)or Ag~+released concentration from antibacterial alloys was much less than the reported minimum inhibitory ion concentrations(MIC),revealing the existence of an unknown alternative antimicrobial mechanism not relying on the toxicity of the metal ions.Herein,we proposed a new antibacterial mechanism that the antibacterial effectiveness of the different alloys is proportional to the micro-area potential differences(MAPDs)on the surface of the alloys.We designed three kinds of Ti-M(M=Zr,Ta and Au)alloys to eliminate the potential antibacterial contribution from Cu and Ag ion.We demonstrated that high MAPDs are associated with great production of reactive oxygen species(ROS),resulting in the killing effect to the biofilm known to be associated with implant infections(Staphlococcus aureus and Escherichia coli).These results provide new insights for the design of antibacterial alloys.
基金Supported by Project of National Natural Science Foundation(41161006)State Key Development Program of Basic Research of China(2012CB723203)+1 种基金National Key Technology Research and Development Program of the Ministry of Science and Technology of China(2012BAD16B0203)Project for Scientific and Technological Innovation Team of Protection and Use of Psammophytes in Gansu Province(1207TTCA002)
文摘To elaborate soil moisture and grain size characteristics of 3 typical micro-areas in Minqin oasis-desert ecotone,samples were collected in runoff generation area and accumulated area using soil profile and multi-point sampling method,for soil moisture and physicochemical property analysis. Research results that( i) water accumulation trace of accumulated area is significant and the vegetation coverage is larger than the runoff generation area. The crust development in clay sand barrier + Haloxylon ammodendron forest accumulated is better than runoff generation area,while the situation is contrary in Nitraria tangutorum sand dune lowland and clay flat land.( ii) Moisture of accumulated area in fixed Nitraria tangutorum sand inter-dune lowland is better than the runoff generation area; the moisture of accumulated area in clay flat land topsoil is significantly better than the runoff generation area,while the topsoil moisture of clay sand barrier + Haloxylon ammodendron forest is better in the runoff generation area than in the accumulated area.( iii) Soil moisture of accumulated area in 3 types of micro-areas is in the range of 20- 40 cm; the fixed Nitraria tangutorum sand inter-dune lowland is better than clay flat land and clay sand barrier + Haloxylon ammodendron forest,while the lowest moisture of corresponding runoff generation area is basically consistent with the depth.( iv) The topsoil clay and powder content in accumulated area of fixed Nitraria tangutorum sand inter-dune lowland is lower than the runoff generation area,while the fine sand content in deep layer of runoff generation area is greater than the accumulated area; soil in two areas of clay flat land mainly consists of coarse and fine sand,and clay particles are better in runoff generation area than in accumulated area. Soil in the clay sand barrier + Haloxylon ammodendron forest is mainly coarse sand and the structure is single. In sum,through adjusting allocation of rainfall,micro-areas influence soil moisture and grain size distribution,and further influence spatial- temporal distribution of vegetation in sand micro-areas.
基金Item Sponsored by National Basic Research Program of China (973 Program) (2004cb619101)
文摘The formation of protective rust layer of atmospheric corrosion resistance was discussed for weathering steel. The rust layers of experimental steels were made by using an accelerating industrial atmospheric corrosion test of dry-wet cyclic immersion. Furthermore XRD were used to measure and analyze the rust layers. The initial corrosion processes below thin water film were observed and the changes of micro-area pH value were measured. The results are as follows： The corrosion processes of P-RE weathering steel are obviously different from those of carbon steel. The surface of P-RE weathering steel rapidly forms a-FeOOH and the micro-area pH value is above 5.4 during the initial corrosion period. While the component of the rust layer for the carbon steel is mainly Fe3O4 and the microarea pH value is below 3.8.
文摘The basic granulite, which is considered to be the MORB based on geochemistry and isotopic characteristics[1], has been discovered recently as the enclaves in the Yingjiang island-arc magmatic suite on the border of Burma and west Yunnan, east of Myitkyina suture in the eastern Burma. The laser micro-area 40Ar-39Ar technique is used to date the age of garnet
