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961.
962.
模拟多光谱卫星传感器数据的冬小麦白粉病遥感监测 总被引:1,自引:0,他引:1
为了解利用遥感技术快速大范围监测小麦白粉病病害情况的可行性,以Landsat5TM波段响应函数为基础,将地面实测冠层高光谱数据模拟为TM多光谱数据,从而分析卫星传感器多光谱波段对病害的响应情况,并构建多光谱指数(PMSI)估测白粉病严重度。在此基础上,采用2010年星-地配套数据对PMSI估测精度进行验证。结果表明,PMSI能够较准确地反映冬小麦白粉病发生的程度,获得较理想的病情严重度反演精度(r2=0.475,RMSE=0.129)。因此采用多光谱卫星遥感影像在小麦大面积种植区域进行病害监测具有应用潜力。 相似文献
963.
Photoactive blend films consisting of sulfonated polyether ether ketone and polyvinyl alcohol were incorporated onto cotton fibers to prepare self-decontaminating cotton fabrics. Electron paramagnetic resonance (EPR) spectroscopy was used to confirm the free-radical nature of the photoactive film and the cotton fabric. Several physical and mechanical properties of the fabrics, such as surface morphology, tensile strength, softness, whiteness, and water vapor permeability, were investigated, and it was found that the treated cottons basically maintained the original performance. Moreover, favorable photo-induced self-decontaminating capabilities of the treated fabrics were demonstrated against three kinds of pollutants, including decomposition of 80.2 % diuron under UVA light irradiation for 3 hours, inactivation of 93.33 % of E.coli and 86.67 % of S.aureus, and degradation of 64.1 % methyl orange under the light irradiation for 1 hour. 相似文献
964.
Promulgated in 1976, “Slopeland Conservation and Utilization Act” aims to regulate the scope of slopelands. “Classification Standard of Slopeland Utilization Limitations” was set forth, classifying slopelands into lands suitable for agricultural, animal husbandry, or forestry purposes or as lands subject to strengthened conservation according to their average slope, soil effective depth, soil erosion degree, and parent rock. Overall inventory was carried out based on the said four factors to verify the classification standard of slopeland utilization limitations. However, the currently verified lands are mostly suitable for forestry or for agriculture and animal husbandry. Scattered placement of these lands results in critical issues such as segmented land use and impaired landscape and ecotype. Especially for lands verified as disaster-prone, they are immediately harmful to land conservation when typhoon or heavy rain occurs. Therefore, this study aims to research rational utilization of slopelands and use for land conservation in Taiwan. Jhuoshuei River is selected as the scope of the case study, using watersheds as analysis units. Seven vulnerability factors are selected, namely total curvature, average slope, average elevation, SPI, standard deviation of aspect, land use, and NDVI, in companion with a model of disaster susceptibility created based on logistic regression; this model interprets the success rate curve of disaster susceptibility and gives an area under the curve of up to 91.1 %. Subsequently, the diagram of disaster potential classification results of the Jhuoshuei River is created via cluster analysis. 相似文献
965.
Hao-Bing Yu Fan Yang Fan Sun Jing Li Wei-Hua Jiao Jian-Hong Gan Wen-Zhen Hu Hou-Wen Lin 《Marine drugs》2014,12(12):6003-6013
Five new alkaloids of aaptamine family, compounds (1–5) and three known derivatives (6–8), have been isolated from the South China Sea sponge Aaptos aaptos. The structures of all compounds were unambiguously elucidated by spectroscopic analyses, as well as by comparison with the literature data. Compounds 1–2 are characterized with triazapyrene lactam skeleton, whereas compounds 4–5 share an imidazole-fused aaptamine moiety. These compounds were evaluated in antifungal and anti-HIV-1 assays. Compounds 3, 7, and 8 showed antifungal activity against six fungi, with MIC values in the range of 4 to 64 μg/mL. Compounds 7–8 exhibited anti-HIV-1 activity, with inhibitory rates of 88.0% and 72.3%, respectively, at a concentration of 10 μM. 相似文献
966.
Yanmin Huang Jianguo Cui Sijing Chen Qifu Lin Huacan Song Chunfang Gan Bin Su Aimin Zhou 《Marine drugs》2014,12(4):1715-1731
Using analogues of some marine steroidal oximes as precursors, a series of aza-B-homocholestane derivatives possessing different substituted groups at the 3-position of the steroidal nucleus were synthesized. Their biological activity against cancer cell proliferation was determined with multiple cancer cell lines. Aza-B-homocholestane derivatives possessing 3-hydroxyl, 3-hydroximino and 3-thiosemicarbazone groups displayed remarkable cytotoxicity to cancer cells via apoptosis inducing mechanism. Compounds 5, 10, 12, 15 and 18 exhibited better potency to inhibit cancer cell proliferation. In addition, compound 15 was further evaluated with three dimensional (3D) multicellular spheroids assay to determine its potency against spheroid growth. The structure-activity relationship (SAR) generated in the studies is valuable for the design of novel chemotherapeutic agents. 相似文献
967.
Seaweed genetic engineering is a transgenic expression system with unique features compared with those of heterotrophic prokaryotes and higher plants. This study discusses several newly sequenced seaweed nuclear genomes and the necessity that research on vector design should consider endogenous promoters, codon optimization, and gene copy number. Seaweed viruses and artificial transposons can be applied as transformation methods after acquiring a comprehensive understanding of the mechanism of viral infections in seaweeds and transposon patterns in seaweed genomes. After cultivating transgenic algal cells and tissues in a photobioreactor, a biosafety assessment of genetically modified (GM) seaweeds must be conducted before open-sea application. We propose a set of programs for the evaluation of gene flow from GM seaweeds to local/geographical environments. The effective implementation of such programs requires fundamentally systematic and interdisciplinary studies on algal physiology and genetics, marine hydrology, reproductive biology, and ecology. 相似文献
968.
Xia Yan Xi-Xiang Tang Lin Chen Zhi-Wei Yi Mei-Juan Fang Zhen Wu Ying-Kun Qiu 《Marine drugs》2014,12(4):2156-2163
Two new indole alkaloids, metagenetriindole A (1) and metagenebiindole A (2), were identified from deep-sea sediment metagenomic clone derived Escherichia coli fermentation broth. The structures of new compounds were elucidated by spectroscopic methods. The two new indole alkaloids demonstrated moderately cytotoxic activity against CNE2, Bel7402 and HT1080 cancer cell lines in vitro. 相似文献
969.
Ming Liu Genzhu Wang Lin Xiao Xuanli Xu Xiaohui Liu Pingxiang Xu Xiukun Lin 《Marine drugs》2014,12(7):3838-3851
Bis(2,3-dibromo-4,5-dihydroxybenzyl) ether (BDDE) is a bromophenol isolated from marine algae. Previous reports have shown that BDDE possesses cytotoxic and antibacterial activity. In the present study, we demonstrate that BDDE displays broad-spectrum antifungal activities, especially on Botrytis cinerea. BDDE inhibits the growth of B. cinerea cultured on a solid medium of potato dextrose agar (PDA) as well as on the potato dextrose broth (PDB) medium. Moreover, BDDE decreases the incidence of fruit decay and severity of strawberries infected with B. cinerea. Further studies have revealed that BDDE decreases the germination rate and inhibits the mycelial growth of B. cinerea. The inhibition mechanisms are related to the disruption of the cell membrane integrity in B. cinerea spores and newly formed germ tubes. This study also suggests that BDDE possibly interacts with DNA via intercalation and minor groove binding. The studies provide evidence that BDDE has potential application in the control of gray mold after fruit harvest and the compound could serve as a candidate or lead template for rational drug design and for the development of antifungal agents. 相似文献
970.
Six new caryophyllene-based sesquiterpenoids named punctaporonins H–M (1–6), together with punctaporonin B (7) and humulane (8) were isolated from the fermentation broth of the sponge-derived fungus Hansfordia sinuosae. Their structures were determined by the extensive HRESIMS and NMR spectroscopic analysis, including the X-ray crystallographic data for the assignment of the absolute configurations of punctaporonins H–I (1–2). The isolated compounds were evaluated for antihyperlipidemic, cytotoxic and antimicrobial activities, and punctaporonin K (4) exhibited potent effects to reduce the triglycerides and total cholesterol in the intracellular levels. 相似文献