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941.
Mette Hedegaard Thomsen Anders Thygesen Henning Jørgensen Jan Larsen Børge Holm Christensen Anne Belinda Thomsen 《Applied biochemistry and biotechnology》2006,130(1-3):448-460
The overall objective in this European Union-project is to develop cost and energy effective production systems for coproduction
of bioethanol and electricity based on integrated biomass utilization. A pilot plan reactor for hydrothermal pretreatment
(including weak acid hydrolysis, wet oxidation, and steam pretreatment) with a capacity of 100 kg/h was constructed and tested
for pretreatment of wheat straw for ethanol production. Highest hemicellulose (C5 sugar) recovery and extraction of hemicellulose
sugars was obtained at 190°C whereas highest C6 sugar yield was obtained at 200°C. Lowest toxicity of hydrolysates was observed
at 190°C; however, addition of H2O2 improved the fermentability and sugar recoveries at the higher temperatures. The estimated total ethanol production was 223
kg/t straw assuming utilisation of both C6 and C5 during fermentation, and 0.5 g ethanol/g sugar. 相似文献
942.
943.
A bioassay-directed chemical analysis (BDCA) scheme has been developed which combines a yeast screen for estrogenic activity with LC–MS detection after liquid–liquid extraction and fractionation by size exclusion chromatography. Focusing on sewage-treatment plant (STP) effluents, the approach aims at characterizing the substances responsible for estrogenic effects in aquatic systems. Initial results show a strong response of STP effluent extracts in the yeast screen. Estrone, bisphenol A, and nonylphenol have been identified as substances being partly responsible for observed estrogenic activity. However, confirmation experiments with synthetic samples revealed that the estrogenic effect potentials of the samples could not be completely assigned to specific compounds. Further improvement of the limits of detection of the analytical scheme is needed to enable identification and quantification of potent estrogenic compounds at low concentrations. 相似文献
944.
用气相色谱-质谱-数据系统联用技术以及红外和核磁共振光谱分析了树兰花净油的化学成份。其萜烯部分除已报道过的(王古)(王巴)烯、丁香烯、蛇麻烯、榄香烯之外,还发现有a-橙椒烯、β-橙椒烯、双环榄香烯、β-檀香烯、γ-木罗烯、金合欢烯、α-木罗烯、β-没药烯、β-荜澄茄烯、γ-荜澄茄烯、δ-荜澄茄烯、γ-榄香烯、白菖烯、甜旗烯等倍半萜烯;而含氧部分的主要成份是茉莉酮酸甲酯和蛇麻烯环氧物Ⅱ;此外还发现有蛇麻二烯酮、蛇麻烯环氧物Ⅰ、蛇麻烯-7醇、丁香烯环氧物、T-荜澄茄醇、δ-荜澄茄醇、表-橙椒醇、橙椒醇、芳萜醇等。 相似文献
945.
946.
合成了一系列四取代吡啶氟硼酸盐,有些对水稻和绿豆显示出良好的抑制生长的活性。 相似文献
947.
The release of H2O2 by plant cell suspensions elicited with crude hyphal wall preparations has been studied in a complex of plant genotypes (two
cvs ofCapsicum annuum and one of C.frutescens) and fungus species(Phytophthora capsici, Ph. parasitica andVerticillium dahliae), representing several combinations of compatibility and both host and nonhost resistance. Production of H2O2 was revealed as peroxidasedependent and catalase-inhibited fluorescence quenching of an extracellular probe (Pyranine).
All the plant genotypes responded to at least one elicitor, but the cell sensitivity showed a great age-dependent variability.
Riboflavine and Mn2+ added in the incubation medium acted to some extent as primers for activated cell response, as well as a high Na+ concentration. Cell rest condition, however, was not removed. Some quantitative features of responsive plant/elicitor combinations
(dose-response relation and lasting time) have been recorded.
The complex PO/H2O2 of elicited cells could perform detectable lignin-like polymerization of an exogenous natural substrate (coniferyl alcohol).
The time-course of pyranine oxidation and lignin-like polymer formation could be recorded by adopting a fluorimetric procedure
that allowed sequential observations on the same cell sample. In one instance, the cell reaction seemed associated with thein planta host/parasite incompatibility. 相似文献
948.
Soil samples collected in the surroundings of a chlor-alkali plant in the Netherlands were characterised by synchrotron-based techniques and conventional analytical procedures, in order to evaluate the environmental impact of Hg emissions and other heavy metals present in these locations. Analysis of total metal content by inductively coupled plasma-optical spectroscopy (ICP-OES) revealed a heterogeneous contamination of Hg, with concentrations ranging from 4.3 to 1150 μg g−1. In addition, significant concentrations of Cu, Ni, Pb, Zn, Mn and principally Fe were also identified within the studied samples. Direct determination of mercury species by X-ray absorption near edge spectroscopy (XANES) showed inorganic Hg compounds to prevail in all soils, being Cinnabar (HgSred) and Corderoite (Hg3S2Cl2) the main species. Nevertheless, more soluble mercury compounds, such as HgO and HgSO4, have been also identified in significant proportion (from 6 to 20% of total mercury content), indicating a potential risk of mercury mobilisation. On the other hand, the application of sequential extraction schemes (SES) revealed large portions of weakly available Hg extracted in the residual fraction, while Hg associated to the exchangeable phase amounts as much as 19% of total Hg, thus, supporting the results obtained by XANES.Finally, synchrotron-based micro X-ray fluorescence (μ-XRF) was applied to identify qualitative trends on elemental associations in sample particles through a systematic mapping of its surface. In this concern, results show a well-defined correlation between Hg and Cu/Ni in the analysed particles. On the other hand, an absence of correlation between Hg and several other elements (Fe, Ti, Ca, Zn, Mn and S) was also observed. These effects have been attributed to chemical and physical interactions of mercury species on both enriched particles and sample matrices. 相似文献
949.
《信阳师范学院学报(自然科学版)》2016,(3):405-411
以大尺度的植物分布信息为基础,结合地理信息系统和统计学分析,对西藏地区的种子植物多样性地理分布格局和多样性分化特点进行了探讨.结果表明,从种到科,植物多样性和区系分化强度的数据集离散度呈递减趋势.与科相比,种、属的植物多样性的空间变异程度更为明显,这可能与种、属和科所代表的不同时期的地质历史有关.相对中部和北部而言,无论是在种、属水平,还是在科水平,西藏地形更为复杂的南部尤其是东南部拥有更高的植物多样性.种子植物的区系分化强度与表征地形复杂度的海拔高差存在显著的正相关关系,这说明复杂的地形可能有利于区系的分化.区系分化强度对研究区域植物多样性的地理分布格局存在明显的影响,这可能与西藏地质历史上地层的差异性抬升引起的气候变迁有关. 相似文献
950.
Mirjam S. Studer Roland Künzli Reto Maier Michael W. I. Schmidt Rolf T. W. Siegwolf Ivan Woodhatch 《Isotopes in environmental and health studies》2017,53(3):286-297
Plant–soil interactions are recognized to play a crucial role in the ecosystem response to climate change. We developed a facility to disentangle the complex interactions behind the plant–soil C feedback mechanisms. The MICE (‘Multi-Isotope labelling in a Controlled Environment’) facility consists of two climate chambers with independent control of the atmospheric conditions (light, CO2, temperature, humidity) and the soil environment (temperature, moisture). Each chamber holds 15 plant–soil systems with hermetical separation of the shared above ground (shoots) from the individual belowground compartments (roots, rhizosphere, soil). Stable isotopes (e.g. 13C, 15N, 2H, 18O) can be added to either compartment and traced within the whole system. The soil CO2 efflux rate is monitored, and plant material, leached soil water and gas samples are taken frequently. The facility is a powerful tool to improve our mechanistic understanding of plant–soil interactions that drive the C cycle feedback to climate change. 相似文献