Monomeric and dimeric phenolic acids released from cell walls of grasses by sequential treatment with sodium hydroxide

Cell walls of tall fescue Festuca arundinacea Schreb and coastal bermudagrass Cynodon dactylon L Pers were treated sequentially with increasing concentrations of sodium hydroxide (0·1 M to 10 M) to release monomeric and dimeric phenolic acids. (E)-p-Coumaric and (E)-ferulic acids were the major monomers released. Most of the saponifiable feruloyl groups (97% for tall fescue, 89% for coastal bermudagrass) were released with 0·1 M sodium hydroxide. Much lower proportions of saponifiable p-coumaroyl groups (67% for tall fescue, 46% for coastal bermudagrass) were released with this treatment. The major dimers from both grasses were 4,4′-dihydroxy-α-truxillic, 4,4′-dihydroxy-3-methoxy-α-truxillic, and 4,4′-dihydroxy-3,3′-dimethoxy-α-truxillic acids, and were mainly released with 0·1 M sodium hydroxide. Similar proportions of the monomers and dimers were released from the cell walls of each grass with the 0·1 M and 1 M sodium hydroxide sequential treatments. It is probable that most if not all of the monomers and dimers released by the sequential alkali treatments were originally ester linked to the cell walls. If it is assumed that the cell wall bound dimers are formed photochemically from p-coumaroyl and feruloyl groups during plant growth, it is calculated that, for the two grasses, between 12 and 17% of the monomer units were converted to dimers.     

二烷氧基对苯乙炔聚合物发光材料的研究 Ⅰ.相转移催化合成中间体1,4-二丁氧基苯

以对苯二酚和溴代正丁烷为原料、乙醇和甲苯为溶剂,在碱性条件下,采用相转移催化剂合成二烷氧基对苯乙炔聚合物发光材料的中间体1,4-二丁氧基苯,考察了不同相转移催化剂和反应条件对产品收率的影响。实验结果表明,以双十八烷基甲基胺氯化苄季铵盐(C_(18)H_(37))2N~+MeCH_2PhCl~-为相转移催化剂,在原料配比n(对苯二酚):n(溴代正丁烷)=1:2.2、催化剂用量(基于对苯二酚的物质的量)2.0%、反应温度60℃、反应时间3.0 h的条件下,1,4-二丁氧基苯的收率达93.6%。通过IR和~1H NMR表征,对产品进行了分析和确认。     

资源型城市选择接替产业的研究

本文把企业竞争战略的理论和方法应用于区域经济的研究,从公共管理部门的角度看待区域经济发展问题,为资源型城市的转型和产业结构的优化提出了可以选择或借鉴的经济发展战略和思路。说明公共管理部门如何通过合理的选择接替产业,实现城市的转型,促进经济的发展,并结合典型的资源型城市大庆加以运用。     

取代水杨醛席夫碱金属配合物结构对硫化物催化氧化性能的影响

将取代水杨醛席夫碱分别与Co(NO₃)₂、Ni(NO₃)₂反应合成了7种席夫碱金属配合物(C1～C7),并考察了其载氧性能,对模型硫化物1-己硫醇、二丁基硫醚、2-甲基噻吩的催化氧化性能及其影响因素。结果表明:配合物的载氧性能主要受其中心离子种类、配体取代基电子效应和空间效应及共轭程度的影响;中心离子与O₂的配位能力越强、配体取代基推电子能力越大且空间位阻越小、共轭链越长越有利于配合物载氧,其中每摩尔C7配合物的载氧量为0.523 mol;配合物的催化氧化性能由其载氧性能和在正辛烷中的溶解度共同决定,载氧量越高、溶解度越大,则对硫化物的催化氧化性能越好;配合物C6的催化氧化性能最佳,且对1-己硫醇和二丁基硫醚的催化氧化性能优于对2-甲基噻吩。     

Highly soluble perylene dyes: Synthesis, photophysical and electrochemical characterizations

Highly soluble perylene diimide derivatives with symmetrical and unsymmetrical secondary, tertiary alkyl side chains were synthesized and their photophysical properties, redox potentials and thermal stabilities were measured and compared with previously reported 1-pentylhexyl substituted swallow-tailed perylene diimide. Diasteroisomers of the novel, unsymmetrical swallow-tailed substituted perylene diimide compound could not be detected using low temperature NMR spectroscopy. The novel dyes were soluble in a range of organic solvents indicating potential for photo-electronic applications and photocatalytic reactions. Two dyes were not only soluble in organic solvents but also showed solubility in aqueous media as the hydrochloride salt, thus offering potential use in biological applications.     

取代苯甲酸葡萄糖酯的合成及生物活性

以两种方法合成了10个取代苯甲酸葡萄糖酯类化合物，一是相转移催化法，二是在三忆胺的存在下，取代苯甲酸与溴代葡萄糖反应，该种合成糖酯的方法未见文献报道，取代苯甲酸葡萄糖酯的结构由IR、MS、^1H NMR和元素分析确认。对化合物的抗病毒活性测试结果发现，其中有两个化合物具有一定的抑制TMV的活性。     

Copolymerization of phenylacetylene with various acetylenes by W- and Mo-based catalysts

In the copolymerization of phenylacetylene with various acetylenes catalysed by WCl₆·Ph₄Sn, the relative reactivity of monomer decreased with increasing steric effect of monomer, e.g. HC  Cn-Bu, HC  Cn-Hex > HC  CPh, HC  Cs-Bu > HC  Ct-Bu, MeCCPh, CICCPh. While 1-chloro-2-phenylacetylene (a disubstituted acetylene) showed high reactivity in the homopolymerization by Mobased catalysts, the reactivity was remarkably depressed in the presence of phenylacetylene as comonomer. Based on these results, the relative reactivity of the acetylenic monomers in copolymerization was explained in terms of competitive coordination of monomers to the propagating end.     

Synthesis and Mutagenic Activity of Bay-Region Bridged Chrysenes

The synthesis of a series of substituted bay-region bridged chrysene derivatives is described. The method involves the oxidative photocyclization of stilbene carboxylic acids followed by dehydration with hydrofluoric acid. The photocyclization of stilbene carboxylic acids lead to secondary photolactonizations and functionalization of a bay region carbon by a novel photolytic process. The mutagenic activity of the substituted chrysenes was determined and activity levels correlated with substituent effects.     

取代苯甲酸对植物生长调节活性的拓扑QSAR研究

应用分子图形学技术计算了13种取代苯甲酸的新型分子连接性指数(mXtv)及电性拓扑指数(En).基于向前逐步回归方法,建立了取代苯甲酸对植物生长的调节活性(pC)与4Xpcv、E16、E40的最佳相关模型,其相关系数为0.947,显示高度拟合性与强的预测能力.该模型经Jackknife法检验,具有可靠性与稳健性.     

A duplex coating composed of electrophoretic deposited graphene oxide inner-layer and electrodeposited graphene oxide/Mg substituted hydroxyapatite outer-layer on carbon/carbon composites for biomedical application

A duplex coating composed of electrophoretic deposited graphene oxide (GO) inner-layer and electrodeposited GO/Mg substituted hydroxyapatite (MH) outer-layer was prepared on carbon/carbon composites (CC). The morphology and microstructure of GO-GO/MH coating were researched by Scanning electron microscopy, energy dispersive X-ray spectroscopy, X-ray diffraction, Raman spectroscopy and X-ray photoelectron spectroscopy. The bonding strength between GO-GO/MH coating and CC substrate was investigated by shear test. The in-vitro bioactivity of GO-GO/MH coating was analyzed by simulated body fluid (SBF) immersion test. The results demonstrated that electrophoretic deposited GO inner-layer was successfully introduced on CC and could serve as an interlayer between CC and following electrodeposited GO/MH outer-layer. GO/MH outer-layer presented a flake morphology with 150–250?nm in thickness and 1.5–2.5?µm in width, exhibiting porous three-dimensional networks structure uniformly. The shear test showed that the bonding strength between the duplex coating and CC reached 7.4?MPa, which was 80.49% higher than that of single-layered MH coating without GO. The duplex coating could induce the formation of flocculent and chapped apatite after SBF immersion, which demonstrated the in-vitro bioactivity of the duplex coating. These results suggested that GO-GO/MH coating might be a promising candidate in the field of biomaterials, especially for implant coatings.