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SYNTHESIS AND free radical POLYMERIZATION OF 2-OXO-3-METHYLEN E-5-PHENYL-1,4-DIOXAN

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Chinese Journal of Polymer Science 1993年第2期11卷 153-157页

作者：冯品珍 Chemistry Department Graduate School Academia Sinica Beijing 100039

The novel cyclic monomer, 2-oxo-3-methylene-5-phenyl-1,4-dioxan, was synthesized by a set of reactions. Several intermediates were prepared and characterized in order to determine the monomer structure. The presence of chiral centers in the intermediates and resulting monomer makes it complicated to separate , purify and characterize them. It is a very reactive monomer which will polymerize even at room temperature if expose to moisture and air. This monomer can undergo essentially quantitative flee radical ring opening polymerization. The driving force for ring opening is the formation of new carbonyl group and benzylic radical. The monomer and polymer structure were established by IR, ~1H NMR, ^(13)C NMR and elemental analysis or high resolution mass spectrum. The molecular weight of the resulting polymer was estimated by viscosity determination.

关键词： free radical Ring opening polymerization Cyclic acrylate

Effects of Longyanshen polysaccharides on free radical metabolism in senescence accelerated-prone mice

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Neural Regeneration Research 2008年第10期3卷 1099-1102页

作者： ZhongshiHuang Haiyuan Xie Shijun Zhang Yang Jiao Weizhe Jiang Renbin Huang Department of Pharmacology Guangxi Medical University Nanning 530021 Guangxi Zhuang Autonomous Region China Department of Biochemistry Youjiang Medical College for Nafionalities Baise 533000 Guangxi Zhuang Autonomous Region China

BACKGROUND： Along with aging, antioxidase activity decreases and oxygen-derived free radicals greatly accumulate, resulting in cellular senescence, or even cell death. This is manifested by hypomnesia and disordered metabolism of free radicals. Studies have reported that Longyanshen polysaccharides have the function of antioxidation and improved brain memory. OBJECTIVE： To observe the effects of Longyanshen polysaccharides on free radical metabolism in brain tissue to verify the anti-aging mechanisms in senescence accelerated-prone （SAMP8） mice. DESIGN, TIME AND SETTING： The randomized, controlled, biochemical experiment was performed in the Department of Pharmacology and Scientific Experimental Center of Guangxi Medical University （China） from September 2005 to January 2008. MATERIALS： Forty SAMP8 mice were randomized into four groups： SAMP8 control group, as well as low-, mid-, and high-dose polysaccharide, with 10 mice in each group. Ten senescence accelerated-resistantprone （SAMR 1） mice served as the normal control group. Longyanshen polysaccharides, extracted from the medical plant Longyanshen, were supplied by the Department of Pharmacology, Guangxi Medical University Superoxide dismutase （SOD）, glutathione peroxidase （GSH-Px）, malonaldehyde （MDA）, nitric oxide （NO）, and total protein test kitwere purchased from Nanjing Jiancheng Bioengineering Institute （China）. METHODS： SAMP8 mice were used to establish a dementia animal model. SAMP8 and SAMR1 control mice were administered 30 mL/kg saline. The low-, middle-, and high-dose polysaccharide groups were administered 45, 90, and 180 mg/kg Longyanshen polysaccharides, respectively. Each group was treated by intragastric administration, once daily, for 50 continuous days. MAIN OUTCOME MEASURES： One hour after the last administration, mouse brain tissues were collected, and retro orbital blood sampling was performed. Spectrophotometry was used to measure SOD and GSH-Px activity, as well as MDA and NO concentration

关键词： free radical superoxide dismutase glutathione peroxidase malonaldehyde nitric oxide Longyanshen polysaccbarides senescence accelerated-prone mice

Election Spin Resonance Studies of free radical Formation and Oxygen Consumption of Lens Epithelium During Ultraviolet Exposure

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眼科学报 1993年第1期9卷 15-18页

作者： Jiemin Xu CunpuSun Ke Wu Jianqiang Shao Qing Shan Jianbo Cong Jianzhong Zhang Beijing Institute of Radiation Medicine Beijing 100850China Graduate School Academia Sinica

A long life election spin resonance (ESR) signal at g=2.0006 was observed in the normal lens epithelium and cortical fibers. During ultraviolet (UV) exposure, a new ESR signal at g = 2.0060 was found in the lens epithelium. But this specific signal was not detected in the lens cortical fibers. This suggested that lens epithelial cells were more susceptible to the free radical formation which was induced by UV light. By means of ESR spin probe oxymetry, the oxygen uptake of lens epithelial cells was meas...

关键词： election spin resonance(ESR) lens epithelium free radical oxygen consumption ultraviolet(UV)exposure

THE　MULTI─ASSOCIATION　MODEL　OF　THE　ESR─ACIDITY　SENSITIVE　free　radical：A　THEORETICAL　STUDY

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中国科学院大学学报(中英文) 1995年第1期 52-60页

作者： Zhu Jina Yan Jing Chen Ya-ling Zhang Jian-zhong Yan Da-yu

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关键词： multi-association model ESR-acidity free radical

Humic acid and free radical in environment of Kaschin-Beck disease areas

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Journal of Environmental Sciences 1991年第4期3卷 95-101页

作者： Ren Shufen, Zhang Xuelin, Li Wencheng, Wang Wensheng, Wang Jinda, Wang Wenjun and Zhang YuxiaChangchun Institute of Geogrophy.Chinese Academy of Sciences,Changchun,China

The humic acid contents in drinking water and soil in Kaschin-Beck disease areas were found more than that of non-disease areas in this research. Changes of free radical concentration in drinking water were agreed with that of humic acid contents in drinking water of Kaschin-Beck disease areas. A positive correlation of free radical concentration and humic acid content in drinking water has been shown (r=0.913) . The structure of I. R. spectra of humic acid under ultraviolet light has been changed. Thus it indicated that free radical was resulted from benzoqiunonyl groups of humic acid in environment.

关键词： humic acid free radical Kaschin-Beck disease.

free radicals trigger the closure of open pores in lignin-derived hard carbons toward improved sodium-storage capacity

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Journal of Energy Chemistry 2024年第7期94卷 551-559页

作者： Wen-Jun Ji Zong-Lin Yi Ming-Xin Song Xiao-Qian Guo Yi-Lin Wang Yi-Xuan Mao Fang-Yuan Su Jing-Peng Chen Xian-Xian Wei Li-Jing Xie Cheng-Meng Chen CAS Key Laboratory of Carbon Materials Institute of Coal ChemistryChinese Academy of SciencesTaiyuan 030001ShanxiChina University of Chinese Academy of Sciences Beijing 100049China Center of Materials Science and Optoelectronics Engineering University of Chinese Academy of SciencesBeijing 100049China School of Environment and Safety Taiyuan University of Science and TechnologyTaiyuan 030001ShanxiChina

The chemical activation of various precursors is effective for creating additional closed pores in hard carbons for sodium ***,the formation mechanism of closed pores under the influence of pore-forming agents is not well ***,an effective chemical activation followed by a high-temperature self-healing strategy is employed to generate interconnected closed pores in lignin-derived hard carbon(HCs).By systematic experimental design combined with electron paramagnetic res-onance spectroscopy,it can be found that the content of free radicals in the carbon matrix influences the closure of open pores at high *** high activation temperature(>700 C)leads to a low free radical concentration,making it difficult to achieve self-healing of open pores at high *** activation at 700°C,a balance between pore making and self-healing is achieved in the final hard carbon.A large number of free radicals triggers rapid growth and aggregation of carbon microcrys-tals,blocking pre-formed open micropores and creating additional interconnected closed pores in as-obtained hard *** a result,the optimized carbon anode(LK-700-1300)delivers a high reversible capacity of 330.8 mA h g^(-1) at 0.03 A g^(-1),which is an increase of 86 mA h g^(-1) compared to the pristine lignin-derived carbon anode(L-700-1300),and exhibits a good rate performance(202.1 mA h g^(-1) at 1 A g^(-1)).This work provides a universal and effective guidance for tuning closed pores of hard carbons from otherprecursors.

关键词： Hard carbon Chemical activation free radical Self-healing Closed pores Sodium ion batteries

Entropy, free radical and Life System

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Open Journal of Biophysics 2016年第4期6卷 83-89页

作者： Honghu Li Junhua Hou College of Physics and Information Engineering Shanxi Normal University Linfen China

Effects of entropy and free radical in life system are elucidated. The results indicate that living organism can maintain normal activities only if a suitable free radicals inside living organism can be guaranteed. Excessive free radical should be eliminated to reduce entropy in living organism. Some ways provided to eliminate excessive free radical, reduce entropy and keep health.

关键词： Entropy free radical Living Organisms

Protection of Acanthopanax Senticosus Saponin on free radical Injury Induced Aging of Nerve Cell

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Chinese Journal of Integrative Medicine 2002年第3期8卷 200-203页

作者：潘永进顾永健顾小苏 Affilated Hospital of Nantong Medical College Jiangsu 226000

Objective To study the effect of Acanthopanax senticosus saponin (ASS) on free radical injury induced neuron aging. Methods On day 7 of fetal mice, cortical neuron primary passage cultures were divided into the normal control group, model group and ASS groups. The model group using free radical (FeSO4 plus H2O2) injury mode prepared in vivo cultured ICR mice cortical neuron aging model; ASS groups: 24 hrs before and after treated with H2O2 and FeSO4, different concentration of ASS was added, according to biochemical parameters such as lactate dehydrogenase (LDH), superoxide dismutase (SOD) and malondialdehyde (MDA) etc. and histomorphologic change to observe the protection of ASS on aging neurons. Results The LDH, SOD,MDA of the model group were compared with the normal group, free radical toxic effect, increase the anti-oxidase activity, strengthen the protection of neuron cells. It is assumed that the effect against nerve cell aging was possibly through scavenging oxygen free radical, strengthening the stability of cell membrane, thus delaying the development of aging.

关键词： Acanthopanax senticosus saponin free radical nerve cell culture aging

Antioxidant defenses and free radical metabolism in the sea cucumber Apostichopusjaponicus （Selenka） during its estivation

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Antioxidant defenses and free radical metabolism in the sea ...