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991.
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994.
Protective action of CLA against oxidative inactivation of paraoxonase 1, an antioxidant enzyme 总被引:2,自引:0,他引:2
The effect of CLA on paraoxonase 1 (PON1), one of the antioxidant proteins associated with HDL, was investigated for its protective
action against oxidative inactivation as well as its stabilization activity. When cis-9 (c9),trans-11 (t11)-CLA and t10,c12-CLA were examined for their protective activity against ascorbate/Cu2−-induced inactivation of PON1 in the presence of Ca2+, two CLA isomers exhibited a remarkable protection (E
max, 71–74%) in a concentration-dependent manner (50% effective concentration, 3–4 μM), characterized by a saturation pattern.
Such a protective action was also reproduced with oleic acid, but not linoleic acid. Rather, linoleic acid antagonized the
protective action of CLA isomers in a noncompetitive fashion. Additionally, the two CLA isomers also protected PON1 from oxidative
inactivation by H2O2 or cumene hydroperoxide. The concentration-dependent protective action of CLA against various oxidative inactivation systems
suggests that the protective action of CLA isomers may be mediated through their selective binding to a specific binding site
in a PON1 molecule. Separately, the inactivation of PON1 by p-hydroxymercuribenzoate (PHMB), a modifier of the cysteine residue, was also prevented by CLA isomers, suggesting the possible
existence of the cysteine residue in the binding site of CLA. The c9,t11-CLA isomer seems to be somewhat more effective than t10,c12-CLA in protecting against the inactivation of PON1 by either peroxides or PHMB, in contrast to the similar efficacy of
these two CLA isomers in preventing ascorbate/Cu2+-induced inactivation of PON1. Separately, CLA isomers successfully stabilized PON1, but not linoleic acid. These data suggest
that the two CLA isomers may play a beneficial role in protecting PON1 from oxidative inactivation as well as in its stabilization. 相似文献
995.
Combined Single-Pass Conversion of Methane Via Oxidative Coupling and Dehydroaromatization 总被引:1,自引:0,他引:1
Yonggang Li Lingling Su Hongxia Wang Hongmei Liu Wenjie Shen Xinhe Bao Yide Xu 《Catalysis Letters》2003,89(3-4):275-279
A new reaction mode, i.e., the combined single-pass conversion of methane via oxidative coupling (OCM) over mixed metal oxide (SLC) catalysts and dehydroaromatization (MDA) over Mo/HZSM-5 catalysts, is reported. With the assistance of an OCM reaction over SLC catalysts in the top layer of the reactor, the deactivation resistance of Mo/HZSM-5 catalysts is remarkably enhanced. Under the selected reaction conditions, the CH4 conversion decreased from 18 to 1% and the aromatics yield decreased from 12.8 to 0.1%, respectively, after running the reaction for 960min on both 6Mo/HZSM-5 and SLC-6Mo/HZSM-5 catalyst system without O2 in the feed. On the other hand, for the SLC-6Mo/HZSM-5 catalyst system with O2 in the feed, the deactivation was improved greatly, and after 960min onstream the CH4 conversion and aromatics yield were still as high as 12.0 and 8.0%, respectively. The promotion effect mainly appears to be associated with in situ formation of CO2 in the OCM layer, which reacts with coke via the reverse Boudouard reaction. 相似文献
996.
Synthesis and characterization of fluorinated polybenzoxazine material with low dielectric constant 总被引:7,自引:0,他引:7
It is well-known that low dielectric materials are used as insulating materials, and the incorporation of fluorinated substitutes into polymer is able to decrease its dielectric constant because of small dipole and the low polarizability of the C–F bond. In this study, a novel structure of the fluorinated benzoxazine (F-1 benzoxazine) has been synthesized by incorporating the trifluoromethyl groups into the monomer, and its structure has also been characterized by 1H NMR, 19F NMR and FT-IR. Further, we have prepared the fluorinated copolybenzoxazine (B-a/F-1=1/1) with substantially reduced dielectric constant at K=2.36. In addition, this fluorinated copolybenzoxazine possesses high glass transition temperature and high thermal stability, which is suitable for high temperature operation for certain special processes of interlayer dielectrics. 相似文献
997.
从某化工厂污水处理车间好氧曝气池的活性污泥中,筛选了一株对非离子表面活性剂Triton X?100具有降解能力的菌株ISB5。对菌株的16S rDNA进行测序和比对分析,将菌株ISB5鉴定为假单胞菌属(Pseudomonas sp.)。进一步对菌株ISB5降解Triton X?100的培养条件进行考察,得到了菌株的适宜降解条件:培养温度为30 ℃,Triton X?100的初始质量浓度为4 g/L,培养时间为28 h,振荡速率为150 r/min,装液量为100.00 mL,接种量为1.00%(菌株ISB5与培养基的体积比)。在该条件下,TritonX?100的降解率可达93.0%以上。 相似文献
998.
应用低供热源变压再生脱碳技术 ,首次对以焦炉气和半水煤气为原料的老厂进行改造 ,取得了预期的效果 ,并总结了经验 相似文献
999.
面对80亿元人民币投资我国子午胎产业的热潮,冷静解剖轮胎产业和市场,按照经济结构分析企业发展趋势,预测子午胎企业2003年市场需求和近几年发展总趋势。提出构筑子午胎企业竞争优势的战略大框架,建议组建国家级联合舰队,提升我国子午胎行业的国际竞争力,规避市场风险。 相似文献
1000.
从设计角度对燕化200kt/a气相法聚丙烯装置的技术改造进行了详细分析和说明。装置改造获得了最大的经济效益,为国内同类装置进行技术改造提供了经验。 相似文献