风景特质评价(Landscape Character Assessment)作为一种管理风景变化的新工具,近年来受到了广泛关注。目前风景特质评价的研究对象多集中在国土尺度或自然乡野地,对于风景名胜区特质的识别研究尚属空白。介绍了风景特质评价的基本流程...风景特质评价(Landscape Character Assessment)作为一种管理风景变化的新工具,近年来受到了广泛关注。目前风景特质评价的研究对象多集中在国土尺度或自然乡野地,对于风景名胜区特质的识别研究尚属空白。介绍了风景特质评价的基本流程,尝试对武当山风景名胜区中的五龙宫景区进行风景特质识别,绘制了武当山风景名胜区的风景特质图,总结了英国风景特质评价作业体系的优缺点及研究局限,提出了今后的研究展望和建议。展开更多
Hyper-spectral data is widely used to determine soil properties. However, few studies have explored the soil spectral characteristics as response to soil erosion. This study analysed the spectral response of different...Hyper-spectral data is widely used to determine soil properties. However, few studies have explored the soil spectral characteristics as response to soil erosion. This study analysed the spectral response of different eroded soils in subtropical China, and then identify the spectral characteristics and soil properties that better discriminate softs with different erosion degrees. Two methods were compared： direct identification by inherent spectral characteristics and indirect identification by predictions of critical soft properties. Results showed that the spectral curves for different degrees of erosion were similar in morphology, while overall reflectance and characteristics of specific absorption peaks were different. When the first method is applied, some differences among different eroded groups were found by integration of associated indicators. However, the index of such indicators showed apparent mixing and crossover among different groups, which reduced the accuracy of identification. For the second method, the correlation between critical soil properties, such as soil organic matter （SOM）, iron and aluminium oxides and reflectance spectra, was analysed. The correlation coefficients for the moderate eroded group were primarily between -0.3 to -0.5, which were worse than the other twogroups. However, the maximum value of R2 was obtained as 0.86 and 0.94 for the non-apparent eroded and the severe group. Furthermore, these two groups also showed some differences in the spectral response of iron complex state （Fep）, Aluminium amorphous state （Alo） and the modelling results for soil organic matter （SOM）. The study proved that it is feasible to identify different degrees of soil erosion by hyperspectral data, and that indirect identification by modelling critical soil properties and reflectance spectra is much better than direct identification. These results indicate that hyper-spectral data may represent a promising tool in monitoring and modelling soil erosion.展开更多
Methyl-CpG-binding domain （MBD） proteins can specifically recognize and bind methylated CpG sites of DNA, thus repress gene transcription. In this study, we designed and expressed two recombinant proteins, MBD2b and...Methyl-CpG-binding domain （MBD） proteins can specifically recognize and bind methylated CpG sites of DNA, thus repress gene transcription. In this study, we designed and expressed two recombinant proteins, MBD2b and SNAP-MBD2b, in E. coli. An optimized protocol was developed to purify the proteins using Ni-NTA affinity cartridge and cation exchange resin. The engineered proteins purified by this method exhibited more than 93% purity and high binding avidity. We found that both SNAP-MBD2b and MBD2b were prone to aggregate during dialysis. However, this could be prevented by the use of 0.3 mol/L NaCI. The fusion of SNAP-tag with MBD2b significantly enhanced the expression of MBD2b protein in E. coli and reduced the adsorption of MBD2b on solid interfaces involved in protein purification and immobilization. The engineered proteins can be used for the study of interaction with methylated DNA and the assays for DNA methylation.展开更多
文摘风景特质评价(Landscape Character Assessment)作为一种管理风景变化的新工具,近年来受到了广泛关注。目前风景特质评价的研究对象多集中在国土尺度或自然乡野地,对于风景名胜区特质的识别研究尚属空白。介绍了风景特质评价的基本流程,尝试对武当山风景名胜区中的五龙宫景区进行风景特质识别,绘制了武当山风景名胜区的风景特质图,总结了英国风景特质评价作业体系的优缺点及研究局限,提出了今后的研究展望和建议。
文摘Hyper-spectral data is widely used to determine soil properties. However, few studies have explored the soil spectral characteristics as response to soil erosion. This study analysed the spectral response of different eroded soils in subtropical China, and then identify the spectral characteristics and soil properties that better discriminate softs with different erosion degrees. Two methods were compared： direct identification by inherent spectral characteristics and indirect identification by predictions of critical soft properties. Results showed that the spectral curves for different degrees of erosion were similar in morphology, while overall reflectance and characteristics of specific absorption peaks were different. When the first method is applied, some differences among different eroded groups were found by integration of associated indicators. However, the index of such indicators showed apparent mixing and crossover among different groups, which reduced the accuracy of identification. For the second method, the correlation between critical soil properties, such as soil organic matter （SOM）, iron and aluminium oxides and reflectance spectra, was analysed. The correlation coefficients for the moderate eroded group were primarily between -0.3 to -0.5, which were worse than the other twogroups. However, the maximum value of R2 was obtained as 0.86 and 0.94 for the non-apparent eroded and the severe group. Furthermore, these two groups also showed some differences in the spectral response of iron complex state （Fep）, Aluminium amorphous state （Alo） and the modelling results for soil organic matter （SOM）. The study proved that it is feasible to identify different degrees of soil erosion by hyperspectral data, and that indirect identification by modelling critical soil properties and reflectance spectra is much better than direct identification. These results indicate that hyper-spectral data may represent a promising tool in monitoring and modelling soil erosion.
基金supported by the National Basic Research Program of China(21077129,20877091,20890112,21125523,20921063)the National Natural Science Foundation of China(2009CB421605,2010CB933502)
文摘Methyl-CpG-binding domain （MBD） proteins can specifically recognize and bind methylated CpG sites of DNA, thus repress gene transcription. In this study, we designed and expressed two recombinant proteins, MBD2b and SNAP-MBD2b, in E. coli. An optimized protocol was developed to purify the proteins using Ni-NTA affinity cartridge and cation exchange resin. The engineered proteins purified by this method exhibited more than 93% purity and high binding avidity. We found that both SNAP-MBD2b and MBD2b were prone to aggregate during dialysis. However, this could be prevented by the use of 0.3 mol/L NaCI. The fusion of SNAP-tag with MBD2b significantly enhanced the expression of MBD2b protein in E. coli and reduced the adsorption of MBD2b on solid interfaces involved in protein purification and immobilization. The engineered proteins can be used for the study of interaction with methylated DNA and the assays for DNA methylation.
