查询词典 hydroxy radical

The method was based on the aromatic hydroxylation of terephthalate by hydroxyl radical, produced from the homolysis of peroxynitrite in weak acid media, to yield a highly fluorescent product, 2-hydroxy-terephthalate, which was then detected fluorimetrically.

具体做法是将ONOO〓在pH 5.0的缓冲液中转化为其共轭酸ONOOH，而ONOOH本身不稳定，均裂生成·OH，·OH进攻对苯二甲酸生成强荧光产物2-羟基对苯二甲酸，利用荧光分析法测定2-羟基对苯二甲酸，从而间接确定ONOO〓的含量。

Results showed that the hybrid monomer could photopolymerize effectively and both free radical and cationic polymerization processes were improved. When 2-Hydroxy-2-methyl-1-phenyl-1-propanone (1173) was introduced into hybrid system containing UVI-6976, the final conversion of propenyl ether double bond and polymerization rate increased obviously. The comparison of photopolymerization kinetics between hybrid and blend system was investigated as well.

结果表明，以硫鎓盐为光引发剂时，这三种杂化单体均可以有效进行杂化光聚合反应，丙烯基醚和丙烯酸酯双键都显示出较快的反应速度和较高的最终转化率，同时在简单结构的硫鎓盐（UVI-6976）引发体系中加入自由基引发剂2-羟基-2-甲基-1-苯基-1-丙酮（1173）后，丙烯基醚双键的阳离子聚合速率和最终转化率都有了很大提高。

The free radical scavenging properties of six Aloe species are to be investigated in some modified chemical system. The antioxidant was purified by silica column and thin layer chromatography and analyzed by HPLC. A fraction was purified from A. brevifolia Mill showed the most effective scavenging activities on 〓 and ·OH (66. 01% and 38. 98% respectively). With the analysis of IR spectrum, UV spectrum and mass spectrum, the structure of FA was identifed as 8-C-D-glucopyranosyl-2- [2-hydroxy] propyl-5-methyl-7-hydroxychromone. Its scavenging activity on free radicals is higher than that of aloe-emodin. Its antioxidant activity may be due to the phenoxyl on glucosyl chromone which can be react with free radicals and form relatively stable free radicals.

本研究利用分别产生超氧阴离子自由基和羟自由基的化学模型体系研究比较了不同品种芦荟提取物的清除活性氧自由基的抗氧化作用，进一步利用硅胶柱结合薄层层析法和反相高压液相色谱法，从短叶芦荟叶子中首次分离了具有较强自由基清除能力（超氧阴离子自由基和羟自由基清除率分别为66.01％和38.98％）的成分FA，利用红外光谱、紫外光谱和质谱等仪器分析结果推断出该活性成分的分子结构为8-C-吡喃葡萄糖-2-[2-羟基]-丙基-5-甲基-7-羟基对氧萘酮，它的自由基清除能力高于芦荟大黄素，是一种天然抗氧化剂。

Using free radical 4-hydroxy-2,2,6,6-tetramethyl-1-piperidinyloxyl as catalyst, the phase transfer catalyzed method of oxidation of anilines to 15 symmetrical azobenzenes with a saturated solution of potassium ferricyanide in 2N aqueous potassium hydroxide and dichloromethane was described for the first time.

用2，2，6，6-四甲基-4-羟基-1-哌啶氮氧自由基为催化剂，芳胺类化合物在饱和铁氰化钾的氢氧化钾溶液和二氯甲烷的两相转移催化下合成了15 个对称取代偶氮苯。

The structures were identified by IR, UV,〓 NMR and element analyses. 2. Free radical 4-hydroxy-2,2,6,6-tetramethyl-1-piperidinyloxyl as catalyst, the phase transfer catalyzed method of oxidation eighteen semicarbazides to N-Aryl-2-Phenyl diazenecarboxamide with a solution of potassium ferricyanide in 2N aqueous sodium hydroxide and dichloromethane is described for the first time.

利用2，2，6，6-四甲基-4-羟基-1-哌啶氮氧自由基为相转移催化剂，在饱和铁氰化钾的2N氢氧化钠溶液与二氯甲烷的两相反应液中，催化氧化十八个取代氨基脲得到十八个相应的新型偶氮化合物N，2-二芳基二氮亚烯甲酰胺，均获得了较高的产率。

And the Honeysuckle's leaves extracts have hydroxy free radical scavenging effects as well. The re-extract by ethyl acetate has obviously scavenging activity when its concentration is 1 mg/mL.

抗氧化实验结果表明，金银花叶乙醇提取物具有一定的抗羟自由基氧化活性，其中乙酸乙酯萃取物在1mg/mL的低浓度下就显示出了较好的效果。

This research utilized the method of organic synthesis, researching different amounts and positions of hydroxy-substituted benzoic acid and serotonin into amide reaction, so as to produce a series of polyhydroxy substituted N-benzoylserotonin derivatives (compound 1-10). Accordingly, this study conducts the following four tests. I. The activity of antioxidant and the experiment of ability to scavenge DPPH free radical, II. The ability of overall antioxidant—the activity of TEAC, III. The activity test of inhibit Tyrosinase, and IV. The study of absorbing UV / VIS Spectrophotometers. This study use trolox, arbutin, and octyl salicylate as the control groups, and to test the ability of anti-oxidation, the activity of inhibit Tyrosinase, and the ability of absorbing UV. This research ultimately intends to investigate the applied value of those compounds into cosmetics.

本研究主要利用有机合成的方法，将不同数量及不同位置的羟基取代苯甲酸化合物与色洛冬宁进行醯胺化反应后，得到一系列的多羟基取代之N-色洛冬宁苯甲醯胺衍生物（化合物1 ~ 10），进行四种不同活性测试方法：一、清除DPPH自由基能力抗氧化活性测试；二、总抗氧化能力活性测试；三、抑制酪胺酸酶活性美白测试；四、紫外线／可见光光谱仪吸收测试，并以水溶性维生素E、熊果素、水杨酸辛酯当作对照组，探讨其抗氧化能力、抑制酪胺酸酶的活性能力与吸收紫外线能力，再进一步探讨其应用於化妆品上的价值。

This one mode pays close attention to network credence foundation of the businessman very much.

这一模式非常关注商人的网络信用基础。

Cell morphology of bacterial ghost of Pasteurella multocida was observed by scanning electron microscopy and inactivation ratio was estimated by CFU analysi.

扫描电镜观察多杀性巴氏杆菌细菌幽灵和菌落形成单位评价遗传灭活率。