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101.
采用恒温搅拌回流的方式制备了[Rh(COD)Cl]_2,并通过正交试验对制备条件进行了优化,得出催化剂适宜制备条件:n(COD)∶n(RhCl_3·3H_2O)为3.5∶1,回流温度80℃,回流时间3 h。将制备的[Rh(COD)Cl]_2作为催化剂用于松节油的氢化反应,通过单因素试验和正交试验考察了反应压力、反应温度、催化剂用量及反应时间对反应的影响,优选出适宜反应条件,即4 g松节油,催化剂用量为松节油质量的2.5%,反应压力2.5 MPa,反应时间4 h,反应温度45℃。在此反应条件下,α-蒎烯转化率为98.21%,产物顺式蒎烷对映选择性为97.46%,收率为95.72%。  相似文献   
102.
长江三角洲地区城市污泥中苯并[a]芘和菲的初步研究   总被引:1,自引:0,他引:1  
To evaluate the contaminated conditions of benzo[a]pyrene (B[a]P) and phenanthrene (PA) in sludge and to ascertain whether B[a]P limit for land application of sludge exists, the contents of B[a]P and PA in 46 sludge samples from 15 cities in the Yangtze River Delta area of China were determined using high performance liquid chromatography (HPLC) coupled with a fluorescence detector after ultrasonic extraction and silica gel cleanup. B[a]P contents ranged from non-detectable to 1.693 mg kg-1 dry weight (DW), averaged 0.402 mg kg-1 DW, and were < 1.0 mg kg-1 DW in most of the sludge samples. PA was found in all the sludge samples analyzed; its contents ranged between 0.028 and 1.355 mg kg-1 DW, with an average value of 0.298 mg kg-1 DW. Most of the sludge samples contained < 0.5 mg kg-1 DW PA. All 46 municipal sludge samples analyzed in this study showed B[a]P contents < 3.0 mg kg-1 DW, which is the limit value for sludge applied to agricultural lands in China. The contents and distributions of B[a]P and PA in municipal sludge were related to sludge types, sources and treatment technologies, along with the physical and chemical properties of these pollutants.  相似文献   
103.
Imaging and measurement of proliferation with computed tomography (CT) and positron emission tomography (PET) provide a noninvasive method for improved staging and monitoring of response to cancer treatment. We evaluated prospectively the proliferation marker 3'-deoxy-3'[18F] fluorothymidine (FLT) in the context of FLT-PET/CT for detection of early response, confirmation of posttreatment response, and prediction of relapse in dogs with non-Hodgkin's lymphoma. Nine dogs with non-Hodgkin's lymphoma who were scheduled to receive five cycles of an investigational cytotoxic chemotherapy agent were included. All dogs received baseline FLT-PET/CT imaging immediately before chemotherapy. Intent was to repeat imaging with FLT-PET/CT at various time points: group 1 ( n =4), 5 days after initiation of chemotherapy and 3 weeks following the last chemotherapy administration; group 2 ( n =5), before the fourth cycle of chemotherapy and 3 weeks following the last administration. Two dogs in group 2 did not undergo repeat PET/CT. Body mass standardized uptake values (SUV) for FLT were calculated for each dog. Eight dogs had initially increased FLT uptake (mean SUVmax=9.8 [2.6–22.3]). Mean SUV decreased significantly for the seven dogs that underwent follow-up PET/CT following chemotherapy (mean SUVmax=3.5 [1.1–7.9], P <0.016). Increased uptake preceded clinical and cytological evidence of relapse in two dogs. Ki-67 immunohistochemistry confirmed decreased proliferation corresponding to decreased SUV in three canine lymph node samples. FLT-PET/CT functional and anatomical imaging shows promise for the evaluation of response to cytotoxic chemotherapy in dogs with non-Hodgkin's lymphoma and for predicting relapse before standard clinical and clinicopathologic confirmation.  相似文献   
104.
A new thiazinedione from Xanthium strumarium   总被引:3,自引:0,他引:3  
Qin L  Han T  Li H  Zhang Q  Zheng H 《Fitoterapia》2006,77(3):245-246
A new thiazinedione was isolated from the fruit of Xanthium strumarium. Its structure was elucidated by a combination of spectral methods.  相似文献   
105.
水稻叶绿素变化与感光性和感温性关系分析   总被引:2,自引:2,他引:0  
摘 要:【研究目的】水稻叶绿素变化与叶片衰老紧密联系,影响叶绿素变化有高温、强光等因素,但叶绿素变化与感光性和感温性方面的研究很少,本文试图分析这两者间的联系,同时分析叶绿素含量本底与叶绿素变化间的联系。【方法】分别通过35、133个材料在广州和湖北荆州两地多组试验,研究用始穗期在不同生态区的变化,即利用出穗促进率,反映水稻不同材料的感光性和感温性,进一步研究出穗促进率与叶绿素含量变化的关系。此外,对叶绿素含量本底不同的材料,按高低进行分类,探讨不同类型材料叶绿素的变化动态。【结果】在始穗后的第14天到第18天叶片叶绿素含量(SPAD值)减少百分率与出穗促进率呈显著的正相关,35、133个材料分别对应的相关系数是0.5093、0.3036。同时本试验还表明叶绿素含量本底高的材料,在始穗后第9-13天其叶绿素降低幅度较本底低的材料小,而在第14-18天降低幅度反而大,差异达显著水平。叶绿素高低两组材料分开进行出穗促进率与叶绿素含量变化的相关分析,表明低SPAD值组的相关系数更高,达极显著水平。【结论】始穗后第14-18天叶绿素变化与感光性和感温性存在显著相关关系,此期叶绿素变化可以作为反映感光性和感温性的指标。  相似文献   
106.
选用来自黑龙江的7个不同基因型小麦品种,以幼胚为外植体,MS为基本培养基,通过选用不同浓度的激素和有机物,设计了4种诱导培养基和10种分化培养基,研究不同基因型在不同培养基上愈伤诱导及植株再生能力。结果显示,7个不同基因型小麦在MS4诱导培养基上均具有较高的愈伤诱导率,平均达92.7%,其中“农麦30”愈伤平均诱导率高达94.4%。不同分化培养基下出芽率与基因型显著相关,不同基因型有不同的最适分化培养基。农麦30和农麦12受激素的种类和量影响较小,10种分化培养基上的出芽率都在较高的水平上,是良好的转基因材料。  相似文献   
107.
滇西4种山茶果实性状变异分析   总被引:1,自引:1,他引:0  
对腾冲红花油茶、五柱滇山茶、云南连蕊茶和怒江红山茶的果实性状变异及性状间的相关性进行分析。结果表明:腾冲红花油茶、五柱滇山茶、云南连蕊茶和怒江红山茶果实在种间及种内均存在极显著的差异,4个物种果实变异系数最大的是单果重为53.94%,其次是果皮厚度为38.81%、果径为27.10%、果高为24.60%,最小的是果形指数为20.99%;物种变异丰富度分析可知:腾冲红花油茶的自然群落的变异最丰富;聚类分析表明腾冲红花油茶与五柱滇山茶果实性状较相似,怒江红山茶与云南连蕊茶果实性状较相似。单果重与果高、果径、果形指数、果皮厚度成极显著的相关关系。  相似文献   
108.
BACKGROUND: Botanical insecticides do not play a major role as crop protectants, but they are beneficial in some applications. The authors investigated the actions of naturally occurring alkaloids on insect nicotinic acetylcholine (ACh) receptors (nAChRs) by evaluating their abilities to inhibit specific binding of [3H]imidacloprid (IMI) to nerve‐cord membranes from Periplaneta americana L. Two alkaloids were also tested for their actions on nAChRs expressed by cockroach neurons using patch‐clamp electrophysiology. RESULTS: Four natural quinolizidine alkaloids (matrine, sophocarpine, cytisine and aloperine) exhibited more than 50% inhibition of [3H]IMI binding at 10 µM , although other compounds were found to have no or low inhibitory activity. The rank order of potency based on concentration–inhibition curves was cytisine > sophocarpine ≥ aloperine ≥ matrine. Patch‐clamp analysis indicated that sophocarpine and aloperine were not agonists of nAChRs expressed in P. americana neurons, yet, at 10 µM , aloperine, but not sophocarpine, suppressed ACh‐induced inward currents significantly. CONCLUSION: Three of the four natural alkaloids tested possess structural moieties that are necessary for interaction with P. americana nAChRs. Aloperine, which possesses a unique structure and showed a distinctive dose–response curve, was found to act as an antagonist. Appropriate modifications of these alkaloids might result in novel insecticidal nAChR ligands. Copyright © 2008 Society of Chemical Industry  相似文献   
109.
The waste Aspergillus niger mycelium and chitosan were cross-linked by epichlorohydrin and then solidified sodium tripolyphosphate to prepare the Aspergillus niger mycelium-chitosan biosorbent for Cu2+. The effects of adsorption time, pH value, temperature, the initial concentration of Cu2+ and the amount of biosorbent on the adsorption efficiency were investigated. Kinetics, intragranular diffusion model, adsorption isotherm equation, thermodynamic model were used to fit the experimental data. The results showed that the adsorption rate increased by increasing the adsorption temperature, adsorption time and pH value. The adsorption rate of Cu2+ reached 99.42% at the adsorption conditions of 0.4 g Aspergillus niger mycelium-chitosan biosorbent, adsorption time 180 min, adsorption temperature 50 ℃, mass concentration of Cu2+ 20 mg/L. The adsorption process conformed to the Freundlich isotherm model. The adsorbed Gibbs free energy became negative, and ΔHθ were ΔSθ are 6.104 2 kJ/mol and 45.258 1 J/(mol·K), respectively, ie the adsorption was a spontaneous endothermic process. Kinetic data analysis showed that the adsorption of Cu2+ by Aspergillus niger mycelia-chitosan biosorbents fitted quasi-second-order kinetic model. © 2018, Editorial Board of «Chemistry and Industry of Forest Products». All right reserved.  相似文献   
110.
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