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231.
Reactive oxygen species (ROS) scavengers, including ascorbate peroxidase, superoxide dismutase, catalase and peroxidase, are the most commonly used biomarkers in assessing an organisms’ response to many biotic and abiotic stresses. In this study, we cloned an 866 bp GST (phi) gene in Lemna minor and investigated its characteristics, expression and enzymatic activities under 75 μmol/L cadmium concentrations in comparison with other ROS scavengers. GST (phi) gene expression patterns were similar to those of other scavengers of ROS. This suggests that GST (phi) might be involved in responding to heavy metal (cadmium) stress and that its expression level could be used as a bio-indicator in monitoring cadmium pollution. 相似文献
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Plant communities were sampled in the lower reaches of the Tarim River,Xinjiang,The results showed that there are 23 species belonging to 21 genera in 11 families,most of which have low occurrence frequency in quadrats.The most common species is Tamarix ramosissima,which occurred in 17 sites accounting for 89.47% of the total 19 sites,Quantitative classification (TWINSPAN) and ordination(CCA) methods were used to study the distribution Patterns of 23 plant species in 19 sites in this valley.TWINSPAN results showed that the plant communities in the middle reaches of the Tarim River could be divided into 3 groups and the sampling sites could be diveded into 7 types in 3 groups .CCA results were consistent with TWINSPAN results ,and showed species distribution patterns correlated with major environmental variables of groundwater level and soil moisture. 相似文献
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Previous electron paramagnetic resonance (EPR) spectroscopic study of gamma-ray-irradiated stishovite at 77 K detected an
Al hole center, which was proposed to be an [O2
3−–Al3+] defect. First-principles quantum-mechanical calculations show that the unpaired spin is 85% localized on one of the six
oxygen atoms at an AlO6 octahedron, while the calculated 27Al hyperfine constants are similar to those determined by EPR experiments. Theoretical results allow us to propose the Al
center to represent an [AlO6]0 defect, and hole hoping among equivalent oxygen atoms is responsible for its detection only at cryogenic temperatures. Theoretical
calculations also show that the diamagnetic precursors [AlO6/H+]0, [AlO6/Li+]0, and [AlO6/Na+]0 are stable in stishovite. The calculated OH bond distance and orientation are in excellent agreement with those inferred
from FTIR spectra and previous theoretical calculations. The calculated [AlO6/Li+]0 and [AlO6/Na+]0 defects suggest that the monovalent cations such as Li+ and Na+ are potentially important in accommodating Al in stishovite in the lower mantle. 相似文献
238.
Cheng-Chao Liu De-Qing Ren Jiang-Pei Dou Yong-Tian Zhu Xi Zhang Gang Zhao Zhen Wu Rui Chen 《天文和天体物理学研究(英文版)》2015,(3):453-460
A high-contrast coronagraph for direct imaging of an Earth-like exoplanet at the visible band needs a contrast of 10-10 at a small angular separation of 4λ/D or less. Here we report our recent laboratory experiment that approaches these limits. Our test of a high-contrast imaging coronagraph is based on our step-transmission apodized filter. To achieve this goal, we use a liquid crystal array as a phase corrector to create a dark hole based on our dedicated algorithm. We have suppressed the diffraction and speckle noise near the point image of a star to a level of 1.68 × 10-9at4λ/D, which can be used for direct imaging of Jupiter-like exoplanets. This demonstrates that a telescope incorporating a high-contrast coronagraph in space has the potential to detect and characterize Earth-like planets. 相似文献
239.
Kuang Wenhui Zhang Shuwen Du Guoming Yan Changzhen Wu Shixin Li Rendong Lu Dengsheng Pan Tao Ning Jing Guo Changqing Dong Jinwei Bao Yuhai Chi Wenfeng Dou Yinyin Hou Yali Yin Zherui Chang Liping Yang Jiuchun Xie Jiali Qiu Juan Zhang Hansong Zhang Yubo Yang Shiqi Sa Rigai Liu Jiyuan 《地理学报(英文版)》2022,32(9):1705-1723
Journal of Geographical Sciences - High-resolution mapping and monitoring of national land use/cover changes contribute significantly to the knowledge of the interaction between human activities... 相似文献
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