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991.
Li N  Zhang JY  Zeng KW  Zhang L  Che YY  Tu PF 《Fitoterapia》2012,83(6):1042-1045
Two new homoisoflavonoids, named ophiopogonone E (1) and ophiopogonanone H (2), together with thirteen known ones (3-15) were isolated from the tuberous roots of Ophiopogon japonicus. Their structures were elucidated by spectroscopic and chemical analyses. Compounds 7 and 15 were isolated from the genus for the first time. In addition, compounds 2-15 were evaluated for their effects on the inhibition of NO production induced by lipopolysaccharide in the murine microglial cell line BV-2. Compounds 2, 4, 6, 7, 10, 11 showed potent inhibitory effects on NO production with IC(50) values of 20.1, 17.0, 7.8, 5.1, 19.2 and 14.4 μM respectively.  相似文献   
992.
华南18个景观树种抗NO2能力研究   总被引:1,自引:0,他引:1  
为探讨18个华南景观树种抗NO2污染能力,以2~3 a生实生苗为材料,通过人工气候室的盆栽试验,在NO2质量体积浓度为2.05 mg/m3的胁迫处理下,测定了叶片表观伤害症状、叶片气体交换参数及相对叶绿素含量等生理生态指标。采用隶属函数法及系统聚类分析法对其抗NO2污染能力进行了综合评价。结果表明,复羽叶栾树(Koelreuteria bipinnata)、穗花棋盘脚(Barringtonia racemosa)和广宁红山茶(Ca-mellia chekiangoleosa)抗NO2污染能力强;大花紫薇(Lagerstroemia speciosa)、紫薇(Lagerstroemia indica)、木棉(Bombax ceiba)、杜鹃红山茶(Camellia azalea)、深山含笑(Michelia maudiae)和澳洲火焰木(Brachychiton acer-ifolius)抗NO2污染能力较强;腊肠树(Cassia fistula)、仪花(Lysidice rhodostegia)和红花荷(Rhodoleia champio-nii)抗NO2污染能力中等;火焰木(Spathodea campanulata)、蓝花风铃木(Tabebuia pentaphylla)、樱花(Prunusserrulata)、红花羊蹄甲(Bauhinia blakeana)和美丽异木棉(Chorisia speciosa)抗NO2污染能力较弱,蓝花楹(Jacaranda mimosifolia)抗NO2污染能力弱。研究结果为华南重度酸污染地区景观树种选择提供参考。  相似文献   
993.
利用木材天然多孔的网状结构及富含活性基团羟基和羧基的特性,通过冷热水循环结合冷冻处理的方式,提高了木材的渗透性;利用脉冲式真空浸渍法将氧化石墨烯(GO)与木材充分结合,再使用热压法将木材内部的GO还原,使木材具有三维导电性能。结果表明:当GO质量浓度为3 mg/m L,压缩率为45%,热压温度为220℃,热压时间为45 min时,木材/石墨烯三维导电材料(3D-W/r GO)性能最佳,纵向、径向和弦向体阻率分别为3.0×102,7.0×102和3.9×103Ω·cm。对3D-W/r GO的形貌、结构和性能进行研究,激光共聚焦显微镜和扫描电子显微镜分析结果表明,还原性氧化石墨烯(r GO)在木材管道中均匀分布;X射线光电子能谱和傅里叶红外光谱表明,GO以酯键和氢键的形式与木材紧密结合,且r GO在木材机体中的还原程度较大;X射线衍射光谱分析显示,材料结晶度数值减小;综合热分析表明,材料的热稳定性有所提高。和木材相比,3D-W/r GO的力学性能及尺寸稳定性均有明显提升,是一种极具前景的导电材料。  相似文献   
994.
针对白炭黑产业园区废水污染成分较复杂的特性,选用氧化钙、氢氧化钙及聚合氯化铝作为混凝药剂,开展了不同加药量(0.1‰、0.2‰、0.4‰、0.6‰、0.8‰、1‰、2‰)的混凝试验,对废水中关键水质指标变化进行了重点分析,藉此全面展现此种废水混凝处理效果并获取最优适用药剂.试验结果表明:三种混凝药剂对于白炭黑废水混凝处...  相似文献   
995.
Despite the spatial significance of Canada's boreal forest, there is very little known about CH4 and N2O emissions from non-peatlands within it. The primary objective of this project was to study the atmosphere–soil exchange of CH4 and N2O at three sites in the boreal forest of central Saskatchewan. In the summers of 2006 and 2007, CH4 and N2O emissions were measured along transects in three different mature forest stands (aspen, black spruce and jack pine) using a sealed chamber method. At the aspen site, the gross rates of mineralization and nitrification, and the relative contribution of nitrification and denitrification to N2O emissions, were also measured using the 15N isotope dilution technique. Results indicated that the jack pine and black spruce sites were slight sinks of CH4 (−0.123 g CH4–C m−2 yr−1and −0.017 g CH4–C m−2 yr−1 respectively in 2006 and −0.095 g CH4–C m−2 yr−1and 0.045 g CH4–C m−2 yr−1 respectively in 2007), whereas the aspen site was a net source (4.40 g CH4–C m−2 yr−1 in 2006 and 19.60 g CH4–C m−2 yr−1 in 2007). The high CH4 emissions at the aspen site occurred at depressions that were water-filled due to above-average precipitation levels in 2005–2007. All three sites had very low cumulative N2O emissions, ranging from −0.002 to 0.014 g N2O–N m−2 yr−1 in both years. The 15N results indicated that N cycling at the aspen site was very conservative, allowing little N to escape the system as N2O; the emissions that did occur were due primarily to a nitrification-related process.  相似文献   
996.
Sinupret® is frequently used as a herbal medicinal product to treat sinusitis, and it was assumed that anti-inflammatory effects might contribute to its overall beneficial properties. Here, we investigated the effects of a Sinupret® drug mixture (SIN) as well as of the novel Sinupret® dry extract (SIN DE) with the latter containing higher concentrations of active ingredients, in an in vivo model of acute inflammation, the carrageenan-induced pleurisy in rats. Both SIN and SIN DE were administered to rats orally at doses of 100 mg/kg (low dose) and 500 mg/kg (high dose) 1 h prior to intrapleural injection of carrageenan. Although both SIN and SIN DE significantly reduced the exudate volume and leukocyte numbers in the pleural exudate at the high and the low dose 4 h after carrageenan injection, the novel SIN DE was more efficient than SIN at the low dose, implying higher efficiency. In parallel, the novel dry extract SIN DE, but not SIN, at 500 mg/kg significantly lowered the levels of prostaglandin (PG)E2 in the exudates and reduced the amounts of cyclooxygenase (COX)-2 protein in the lungs. Together, SIN and SIN DE exert significant oral anti-inflammatory effects, which rationalize their therapeutic use in the management of sinusitis and other viral/microbial nasal infections that are associated with inflammation. Moreover, our results suggest that based on the higher efficiency and the accompanied reduction of COX-2 expression and PGE2 formation, the novel dry extract SIN DE might be superior over the former SIN drug mixture.  相似文献   
997.
对采用硝酸法从废钨铜合金中回收金属钨和铜,以及转化有害的氮氧化物的方法进行了探讨.并设计了数种较小规模的回收装置.经实验表明,本法具有操作简便、投资省、能耗低、污染小等特点,具有一定的实用价值.  相似文献   
998.
以竹粉为原料制备纳米纤维素基体材料,以聚乙烯醇(PVA)为增强相,在酸性环境下采用冷冻干燥法制得PVA/CNFs(纳米纤维素)复合气凝胶;采用三甲基氯硅烷(TMCS)对其进行疏水改性处理,随后将其浸渍到还原氧化石墨烯(r GO)悬浮液中,最终制得疏水型r GO/PVA/CNFs复合气凝胶;通过扫描电子显微镜(SEM)、傅里叶变换红外光谱(FT-IR)、拉曼光谱(Raman)、接触角(CA)和吸油性能测试,对所制气凝胶的微观形貌、化学结构、疏水性能及吸油性能进行表征。结果表明:制得的复合气凝胶密度为6.78 mg/cm3,具有均匀的三维网状多孔结构,且孔洞结构表面均被石墨烯片层覆盖;经过TMCS疏水处理后,在气凝胶表面形成疏水层结构。FT-IR和Raman分析表明,TMCS疏水改性处理并未改变PVA/CNFs复合气凝胶的化学结构。经疏水处理后气凝胶与水的接触角为138°左右,吸油倍率为78 g/g左右,且吸附过程迅速,饱油后也能悬浮于溶液表面,便于回收再利用。  相似文献   
999.
基于"荷叶效应"仿生原理,首先采用传统一步法和晶核辅助生长法合成ZnO纳米颗粒,再通过层层自组装法分别在竹材表面构建2种不同的微纳结构,并用低表面能物质十七氟癸基三甲氧基硅烷进行修饰,获得超疏水层,最后对其性能进行表征。扫描电子显微镜和原子力显微镜观察显示,传统一步法制备的ZnO纳米颗粒呈球形结构,粒径为200~400 nm,在竹材表面相对分散,粗糙度为18.6;而晶核辅助生长法制备的ZnO纳米颗粒呈纺锤形,粒径为100~300 nm,且具有明显的分层结构,粗糙度为28.9。水静态接触角测试结果显示,随着自组装次数增加,接触角先增加后减少,当自组装次数达到20次时,传统一步法和晶核辅助生长法制备的ZnO纳米颗粒构建的微纳层的水静态接触角达到最大值,分别为142.4°和152.4°,后者达到了超疏水的要求。酸碱试剂浸渍评价纳米颗粒的耐久性结果表明,2种方法制备的ZnO纳米颗粒在强酸强碱溶液中浸泡后,接触角均无明显变化,传统一步法制备的竹材接触角在pH 2的盐酸和pH 12的氢氧化钠溶液中分别浸渍12 h后,接触角仍保持在141.1°和141.7°;晶核辅助生长法制备的竹材在pH 2的盐酸和pH 12的氢氧化钠溶液中分别浸渍12 h后,接触角仍保持在150.2°和150.8°。耐磨性测试结果表明,2种方法制备的疏水竹材具有较好的耐磨性,在30cm的线性摩擦试验后,传统一步法制备的竹材接触角仍在142°左右,晶核辅助生长法制备的竹材接触角在150°左右。X射线衍射测试结果显示,2种方法制备的疏水涂层均具有明显的ZnO晶体的衍射特征峰。2种竹材样品在XRD曲线上均出现了32.45°,34.76°,36.82°和47.65°等一系列新衍射峰,而且这些衍射峰与标准的纤锌矿ZnO的XRD卡片(JCPDS,36-1451)一致。  相似文献   
1000.
The ethylacetate and n-butanol fractions of ethanolic extract of Platanus orientalis leaves led to the isolation of new acylated flavonol glycoside as 3',5,7-trihydroxy-4'-methoxyflavonol 3-[O-2-O-(2,4-Dihydroxy)-E-cinnamoyl-α-L-rhamnopyranosyl-(1→6)-β-D-glucopyranosyl (1→2)]-β-D-glucopyranoside, along with seven known compounds. All the compounds were characterized by NMR including 2D NMR techniques. The isolates were evaluated for NF-κB, nitric oxide (NO), aromatase and QR2 chemoprevention activities and some of them appeared to be modestly active.  相似文献   
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