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991.
Xiaojin Zou Haoge Li Wentao Sun Ning Yang Niu Shiwei 《Archives of Agronomy and Soil Science》2019,65(5):612-624
Intercropping is practised globally because of its advantages in terms of productivity and resource use efficiency. However, our knowledge on the molecular mechanisms underlying belowground interspecific interactions in intercropping systems is still very limited. Pot experiments involving both intercropped millet and peanut were conducted to quantify the differentially expressed proteins in each component crop under conditions of complete, partial and no interspecific interactions based on tandem mass tag (TMT) labelling. The results showed that the yields of both crops in the intercropping system increased in response to complete root interactions due to increases in nutrient acquisition as well as increases in root length and surface area. There were 73 differentially expressed proteins in the millet roots and 41 in the peanut roots, most of which were involved in C metabolism, N metabolism, transport and signal transduction. Additional bioinformatic analyses revealed that root interactions improved N and P assimilation via relatively high amounts of proteins such as urease and inorganic phosphate transporter in the millet roots and malate dehydrogenase increased P assimilation related proteins in the peanut roots. These results would contribute to a comprehensive understanding at molecular level in cereal/legume intercropping systems in response to interspecific root interactions. 相似文献
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993.
振动能量俘获是获取可再生清洁能源的一种有效途径,具有广阔的应用前景,有利于社会的可持续性发展。目前,随机功率谱激励下的高功率密度和宽频能量回收仍然是研究的难点。该研究设计了一种可有效利用宽频振动能量的高功率密度磁浮式俘能器,采用COMSOL Multiphysics软件计算悬浮磁体非线性回复力与位移的关系式,根据磁浮振动系统的控制方程和基尔霍夫定律建立俘能器的数学模型,详细研究了模型参数变化对俘能器性能的影响。随后进行正弦扫频和驻频试验以验证俘能器的发电能力。同时,从俘能器的效率、效能和体积优值3个指标对俘能性能进行评价;并结合实际应用,设计俘能器稳压电路。根据丘陵山区农业机械工作的随机路谱特性,建立随机激励的数学模型,根据响应幅值的概率密度函数的FPK方程表达式,得到了平稳概率密度函数的解。结果表明:在激励频率从9.77到31.75 Hz变化时,俘能器最大输出电压在5.92和21.52 V之间;最大输出功率在10 Hz时达81.93 mW,从5到50Hz,输出功率范围为5.76到81.93 mW;俘能器的效率、效能和体积优值分别为2.85%、9.85%和39.74%;俘能器电压输出的... 相似文献
994.
Cai YZ Xing J Sun M Zhan ZQ Corke H 《Journal of agricultural and food chemistry》2005,53(26):9940-9948
Rosa chinensis (Yuejihua) is a well-known ornamental plant, and its flowers are commonly used in traditional Chinese medicine. Methanolic crude extracts of dried R. chinensis flowers were used for simultaneous determination of phenolic constituents by liquid chromatography-mass spectrometry (LC-MS) and matrix-assisted laser desorption/ionization quadrupole ion trap time-of-flight mass spectrometry (MALDI-QIT-TOF MS). A total of 36 known and unknown phenolics were identified as hydrolyzable tannins, flavonols, and anthocyanins, mainly including gallotannins (mono-, di-, or trigalloylglucopyranosides), ellagitannins, quercetin, quercetin/kaempferol mono- and diglycosides, and cyanidin/pelargonidin diglycosides. MALDI-QIT-TOF MS was applied not only to verify most phenolics isolated and identified by LC-MS but also to tentatively identify two ellagitannins (rugosins B and C) not isolated and unidentified by LC-MS. This study is the first to demonstrate the rapid and successful use of MALDI-QIT-TOF MS and LC-MS to directly and simultaneously identify phenolics in the crude extracts of R. chinensis flowers without any purification. The antioxidant activity of the crude extracts from R. chinensis flowers was also measured with three assay methods. The results showed that the phenolic antioxidants from R. chinensis flowers exhibited very strong radical scavenging effect and antioxidant power. High levels of flavonols and hydrolyzable tannins might be important bioactive principles in the dried R. chinensis flowers. 相似文献
995.
本文分析了东江水源区(东江上中游)水土资源持续利用的主要问题在于原生植被的过度砍伐。果业开发和速生商品林的建设及工业项目开发建设水保措施不落实,工业污染和城乡“三废”未有效处理。水资源受益区与保护区行政区划分隔,上下游水土资源保护的得、失不平衡;同时,提出了从落实各地政府的水土资源保护责任、建立流域生态协商机制、探索流域生态补偿机制等方面促进生态环境改善和水土资源可持续利用。 相似文献
996.
Extraction of Antioxidants from Wheat Bran Using Conventional Solvent and Microwave-Assisted Methods
David S. Oufnac Zhimin Xu Ting Sun Cristina Sabliov Witoon Prinyawiwatkul J. Samuel Godber 《Cereal Chemistry》2007,84(2):125-129
Total phenolic and tocopherol contents and free radical scavenging capability of wheat bran extracted using conventional and microwave-assisted solvent extraction methods were studied. Three different solvents (methanol, acetone, and hexane) were used in the conventional solvent extraction. Methanol was the most effective solvent, producing higher extraction yield (4.86%), total phenolic compound content (241.3 μg of catechin equivalent/g of wheat bran), and free radical scavenging capability (0.042 μmol of trolox equivalent/g of wheat bran) than either acetone or hexane. However, there was no significant difference in the total tocopherol contents (13.6–14.8 μg/g of wheat bran) among the three different solvent extraction methods. Microwave-assisted solvent extraction using methanol significantly increased the total phenolic compound content to 467.5 and 489.5 μg of catechin equivalent; total tocopherol content to 18.7 and 19.5 μg; and free radical scavenging capability to 0.064 and 0.072 μmol of trolox equivalent/g of wheat bran at extraction temperatures of 100 and 120°C, respectively. However, extraction yields of conventional methanol solvent and microwave-assisted methanol extractions at different temperatures were not significantly different. 相似文献
997.
Hesperidin is a flavanone glycoside widely available for dietary intake in citrus fruits or citrus fruit derived products; however, exhaustive and reliable data are scarcely available for biological activity when it exerts protective health effects in humans. The principal intent of this work is to check binding domain and structural changes of human serum albumin (HSA), the primary carrier of flavonoids, in blood plasma association with hesperidin by employing molecular modeling, steady state and time-resolved fluorescence, and circular dichroism (CD) methods. From molecular modeling simulations, subdomains IIA and IIIA, which correspond to Sudlow's sites I and II, respectively, were earmarked to possess affinity for hesperidin, but the affinity of site I with flavanone is greater than that of site II. This corroborates the site-specific probe and hydrophobic 8-anilino-1-naphthalenesulfonic acid (ANS) displacement results placing the hesperidin at warfarin-azapropazone and indole-benzodiazepine sites. Steady state and time-resolved fluorescence manifested that static type, due to HSA-hesperidin complex formation (1.941 × 10(4) M(-1)), is the operative mechanism for the diminution in the tryptophan (Trp)-214 fluorescence. Moreover, via alterations in three-dimensional fluorescence and CD spectral properties, we can securely draw the conclusion that the polypeptide chain of HSA is partially destabilized after conjugation with hesperidin. We anticipate that this study can provide better knowledge of bioavailability such as absorption, biodistribution, and elimination, of hesperidin in vivo, to facilitate the comprehension of the biological responses to physiologically relevant flavanones. 相似文献
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999.
1000.
北方温室为种植反季节植物以及南方植物,普遍采用地埋供热金属管道供热。阴极保护技术可以有效控制土壤对管道的电化学腐蚀,但常规的外接电流阴极保护方式成本高、占地大,牺牲阳极方式的保护寿命过短。为了给温室地埋供热金属管道提供可靠的阴极保护,该文利用地埋供热金属管道表面余热,基于温差电池,对地埋供热金属管道提供外接电流方式的阴极保护。通过现场试验发现,该装置温差电池正常工作时冷热两端温差为33.2℃,当该装置提供的保护电位为–1 100 m V时,管道保护度达到了92.79%。该研究为温室地埋供热金属管道的保护提供了一种较为可行的方案,同时也对外接电流方式的短距离管道保护技术进行了初步探索。 相似文献