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Free radicals trigger the closure of open pores in lignin-derived hard carbons toward improved sodium-storage capacity 被引量:1
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作者 Wen-Jun Ji Zong-Lin Yi +8 位作者 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 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2024年第7期551-559,共9页
The chemical activation of various precursors is effective for creating additional closed pores in hard carbons for sodium storage.However,the formation mechanism of closed pores under the influence of pore-forming ag... The chemical activation of various precursors is effective for creating additional closed pores in hard carbons for sodium storage.However,the formation mechanism of closed pores under the influence of pore-forming agents is not well understood.Herein,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 temperatures.Excessively high activation temperature(>700 C)leads to a low free radical concentration,making it difficult to achieve self-healing of open pores at high tempera-tures.By 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 carbons.As 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. 展开更多
关键词 Hard carbon Chemical activation free radical SELF-HEALING Closed pores Sodium ion batteries
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Correlation of free radical level and apoptosis after intracerebral hemorrhage in rats 被引量:6
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作者 韩宁 丁素菊 +1 位作者 吴涛 朱幼丽 《Neuroscience Bulletin》 SCIE CAS CSCD 2008年第6期351-358,共8页
Objective To investigate the correlation of perihematomal free radical level and neuronal apoptosis following the intracerebral hemorrhage (ICH). Methods Animals were randomly divided into 4 groups: sham operation ... Objective To investigate the correlation of perihematomal free radical level and neuronal apoptosis following the intracerebral hemorrhage (ICH). Methods Animals were randomly divided into 4 groups: sham operation group, model group, 1 mg/kg edaravone group, and 3 mg/kg edaravone group. Each group was then divided into seven subgroups, in which the rats were correspondingly killed at 6 h, 12 h, 24 h, 48 h, 72 h, 7 d or 14 d (n = 1 in each subgroup of the sham group, and n = 6 in each subgroup of the other 3 groups). By Horseley-Clarke technique, autoblood (80 μL) were administered into the left caudate putamen of SD rats in a double administration-withdrawal way. Rats in the sham group were needled in but not administered with autoblood. The ICH model was then evaluated by Bederson's scale. Around the hematoma, the levels of malonaldehyde (MDA) and hydroxyl radical were tested by spectrophotometer, and the process of apoptosis was tested by terminal deoxynucleofidyltransferase-mediated dUTP-biotin nick end labeling (TUNEL) method. Results (1) ICH significantly increased the levels of MDA and hydroxyl radicals. Significant differences in MDA and hydroxyl radical contents were observed among the four groups. (2) In the sham group, a small number of TUNEL-positive cells were found. In the other three groups, the TUNEL-positive cells were observed at 6 h, increased significantly at 24 h, and reached peak level at 3 d, then fell profoundly at 7 d, but remained detectable at 14 d. (3) The positive correlation existed between apoptosis and free radical level (r = 0.2003), and existed between apoptosis and MDA content (r = 0.6563) in the brain. Conclusion Post-hemorrhagic apoptosis was related to the production of free radicals, indicating that the elevated free radicals following the ICH could induce neuron and glial cell apoptosis. 展开更多
关键词 intracerebral hemorrhage free radical APOPTOSIS TUNEL EDARAVONE
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Oxidative mechanism of chicken wooden breast myofibrillar protein
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作者 Ke Wang Yimin Zhang Jingxin Sun 《Food Science and Human Wellness》 SCIE CAS CSCD 2024年第6期3415-3423,共9页
To explore the oxidation mechanism of wooden breast myofibrillar protein(WBMP),oxidative breast MP(OBMP)was obtained from different doses(3,10,and 20 mmol/L)of H2O2 oxidized normal breast MP(NBMP).The results showed t... To explore the oxidation mechanism of wooden breast myofibrillar protein(WBMP),oxidative breast MP(OBMP)was obtained from different doses(3,10,and 20 mmol/L)of H2O2 oxidized normal breast MP(NBMP).The results showed that the Zeta-potential,particle size,solubility,sulfhydryl,and carbonyl contents of OBMP-3(3 mmol/L,low-dose free radicals)and WBMP were similar.Fluorescence spectrum analysis showed that the oxidation of low-dose free radicals led to a significant increase in the surface hydrophobicity(from 214.03±10.03 to 393.50±10.33)and tryptophan fluorescence intensity(from 185.71 to 568.32).In addition,theα-helix content of WBMP decreased significantly from(37.46±1.15)%(NBMP)to(34.70±2.04)%,whileβ-sheet and random coil contents increased significantly(P<0.05)from(14.37±0.69)%and(22.24±0.78)%(NBMP)to(17.70±0.87)%and(25.20±1.47)%(WBMP).In summary,low-dose free radical oxidation attacks protein groups,inducing secondary and tertiary structural changes,leading to the formation of WBMP.This work will provide a theoretical basis at the molecular level for exploring the mechanism of functional degradation of WBMP. 展开更多
关键词 Wooden breast Myofibrillar protein free radical OXIDATION Physicochemical property Molecular structure
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In Vitro Antioxidant and Radio Protective Activities of Lycopene from Tomato Extract against Radiation—Induced DNA Aberration
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作者 Safaiatul Islam Abu Hena Mostofa Kamal +2 位作者 Md. Ziaur Rahman Protul Kumar Roy A.Y.K. Md. Masud Rana 《Journal of Biosciences and Medicines》 2024年第2期202-213,共12页
Background: The accumulation of free radicals is linked to a number of diseases. Free radicals can be scavenged by antioxidants and reduce their harmful effects. It is therefore essential to look for naturally occurri... Background: The accumulation of free radicals is linked to a number of diseases. Free radicals can be scavenged by antioxidants and reduce their harmful effects. It is therefore essential to look for naturally occurring antioxidants that come from plants, as synthetic antioxidants are toxic, carcinogenic and problematic for the environment. Lycopene is one of the carotenoids, a pigment that dissolves in fat and has antioxidant properties. Materials and Methods: The antioxidant and free radical scavenging activity were assessed using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay. The impact of lycopene on bacteria (E. coli) susceptibility to γ-radiation was examined by radio sensitivity assay. The study also examined the induction of strand breaks in plasmid pUC19 DNA and how lycopene extract protected the DNA from γ-radiation in vitro. Results: At varying concentrations, lycopene demonstrated its ability to scavenge free radicals such as 2, 2-diphenyl-1-picrylhydrazyl (DPPH). IC<sub>50</sub> for lycopene was determined at 112 μg/mL which was almost partial to IC<sub>50</sub> of standard antioxidant L-ascorbic acid. The D<sub>10</sub> value 180 Gy of E. coli was found to be >2-fold higher in the extract-containing lycopene sample than in the extract-free controls. The lycopene extracts inhibited the radiation-induced deterioration of the plasmid pUC19 DNA. At an IC<sub>50</sub> concentration, lycopene provided the highest level of protection. Conclusion: Lycopene functions as an efficient free radical scavenger and possible natural antioxidant source. For cancer patients and others who frequently expose themselves to radiation, lycopene may be a useful plant-based pharmaceutical product for treating a variety of diseases caused by free radicals. 展开更多
关键词 Radio Protective ANTIOXIDANTS free Radical DNA Damage pUC19 Plasmid Gamma Irradiation DPPH
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Advancements in Polymer Science: Synthesis, Characterization, and Biomedical Applications of Homopolymers and Copolymers
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作者 Anaif M. Alhewaitey Ishrat Khan Emmanuel Ramsey Buabeng 《Open Journal of Polymer Chemistry》 2024年第3期167-198,共32页
Polymer science encompasses a different range of materials critical to industries spanning from packaging to biomedicine. Understanding the synthesis, characterization, and applications of common homopolymers and copo... Polymer science encompasses a different range of materials critical to industries spanning from packaging to biomedicine. Understanding the synthesis, characterization, and applications of common homopolymers and copolymers is fundamental to advancing polymer research and development. In this comprehensive review, we explore various preparation methods, including free radical, anionic, and cationic polymerization, utilized for synthesizing homopolymers and copolymers. Furthermore, we investigate solvent choices commonly employed for polymer characterization, ranging from neat conditions, polar protic and polar aprotic solvents. We also explored characterization techniques, including Fourier Transform Infrared Spectroscopy (FTIR), Nuclear Magnetic Resonance (NMR), Atomic Force Microscopy (AFM), Differential Scanning Calorimetry (DSC), and Thermogravimetric Analysis (TGA). In addition to industrial applications, we highlight the diverse biological applications of homopolymers, poly(2-hydroxyethyl methacrylate) (pHEMA) and polystyrene, which find its extensive use in biomedicine. By synthesizing and analyzing this wealth of information, this review aims to provide a comprehensive understanding of the synthesis, characterization, and applications of homopolymers and copolymers, with a particular focus on their biological applications. This holistic approach not only contributes to advancements in polymer science and technology but also fosters innovation in biomedicine, ultimately benefiting human health and well-being. 展开更多
关键词 HOMOPOLYMER COPOLYMER Poly(2-hydroxyethyl methacrylate) (pHEMA) Polystyrene free Radical Polymerization Atomic Force Microscopy Solvent Polarity
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Oxidative Stress and Free Radical Damage in Patients With Acute Dipterex Poisoning 被引量:15
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作者 JUN-FuZHOU WENZHOU +2 位作者 SHU-MEIZHANG YAN-ERLUO HUAI-HONGCHEN 《Biomedical and Environmental Sciences》 SCIE CAS CSCD 2004年第2期223-233,共11页
Objective To investigate whether acute dipterex poisoning (ADP) may cause oxidative stress and free radical damage in the bodies of acute dipterex poisoning patients (ADPPs), and to explore the mechanisms by which ADP... Objective To investigate whether acute dipterex poisoning (ADP) may cause oxidative stress and free radical damage in the bodies of acute dipterex poisoning patients (ADPPs), and to explore the mechanisms by which ADP may cause oxidative stress and free radical damage. Methods Fifty ADPPs and fifty healthy adult volunteers (HAVs) whose ages, gender and others were matched with the ADPPs were enrolled in a randomized controlled study, in which concentrations of nitric oxide (NO), vitamin C (VC), vitamin E (VE) and P-carotene (P-CAR) in plasma as well as concentration of lipoperoxide (LPO), and activities of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPX) and acetylcholinesterase (AChE) in erythrocytes were determined by spectrophotometric analytical methods. Results Compared with the average values of experimental parameters in the HAVs group, the average values of plasma NO and erythrocyte LPO in the ADPPs group were significantly increased (P<0.0001), while those of plasma VC, VE and P-CAR as well as erythrocyte SOD, CAT, GPX and AChE in the ADPPs group were significantly decreased (P<0.0001). Bivariate correlation analysis and partial correlation analysis suggested that when NO and LPO values were increased, and VC, VE, β-CAR, SOD, CAT and GPX values were decreased in the ADPPs, AChE value was decreased gradually in the ADPPs (P<0.001-0.0001). Reliability analysis of experimental parameters reflecting oxidative stress and free radical damage in the ADPPs showed that the reliability coefficient (8 items) alpha=0.6909, and the standardized item alpha=0.8574. Conclusion The findings in the present study suggest that ADP can cause oxidative stress and free radical damage, and inhibit markedly erythrocyte acetylcholinesterase activity in ADPPs. 展开更多
关键词 Dipterex Dipterex poisoning Oxidative stress free radical damage free radicals Oxidation LIPOPEROXIDATION ACETYLCHOLINESTERASE
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Effect of resveratrol on pancreatic oxygen free radicals in rats with severe acute pancreatitis 被引量:18
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作者 Zhen-Dong Li Qing-Yong Ma Chang-An Wang 《World Journal of Gastroenterology》 SCIE CAS CSCD 2006年第1期137-140,共4页
AIM: To investigate the therapeutic effects of resveratrol (RESV) as a free radical scavenger on experimental severe acute pancreatitis (SAP). METHODS: Seventy-two male Sprague-Dawley rats were divided randomly ... AIM: To investigate the therapeutic effects of resveratrol (RESV) as a free radical scavenger on experimental severe acute pancreatitis (SAP). METHODS: Seventy-two male Sprague-Dawley rats were divided randomly into sham operation group, SAP group, and resveratrol-treated group. Pancreatitis was induced by intraductal administration of 0.1 mL/kg 4% sodium taurocholate. RESV was given intravenously at a dose of 20 mg/kg body weight. All animals were killed at 3, 6, 12 h after induction of the model. Serum amylase, pancreatic superoxide dismutase (SOD), malondialdehyde (MDA), and myeloperoxidase (MPO) were determined. Pathologic changes of the pancreas were observed under optical microscope. RESULTS: The serum amylase, pancreatic MPO and the score of pathologic damage increased after the induction of pancreatitis, early (3, 6 h) SAP samples were characterized by decreased pancreatic SOD and increased pancreatic MDA. Resveratrol exhibited a protective effect against lipid peroxidation in cell membrane caused by oxygen free radicals in the early stage of SAP. This attenuation of the redox state impairment reduced cellular oxidative damage, as reflected by lower serum amylase, less severe pancreatic lesions, normal pancreatic MDA levels, as well as diminished neutrophil infiltration in pancreas. CONCLUSION: RESV may exert its therapeutic effect on SAP by lowering pancreatic oxidative free radicals and reducing pancreatic tissue infiltration of neutrophils. 展开更多
关键词 Severe acute pancreatitis RESVERATROL Oxygen free radical NEUTROPHIL
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Inhibitory effects of grape procyanidins on free radical-induced cell damage in rat hepatocytes in vitro 被引量:10
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作者 Jin-Yi Zhong Hong-Qun Cong Li-Hua Zhang 《World Journal of Gastroenterology》 SCIE CAS CSCD 2007年第19期2752-2755,共4页
AIM: To study the protective effect of grape procyanidins on oxidative injury induced by ethanol and carbon tetrachloride in rat hepatocytes. METHODS: Normal rat hepatocytes as well as cells damaged by ethanol or ca... AIM: To study the protective effect of grape procyanidins on oxidative injury induced by ethanol and carbon tetrachloride in rat hepatocytes. METHODS: Normal rat hepatocytes as well as cells damaged by ethanol or carbon tetrachloride were incubated with different doses of grape procyanidins for 24 h. Cell proliferation, apoptosis and TNFα mRNA expression were subsequently determined using MTT assay, cell death ELISA and in situ hybridization. RESULTS: Proliferative levels of the control cells from ethanol and CCh injury groups significantly decreased while apoptosis and TNFα mRNA expression significantly increased compared to the normal control and grape procyanidins co-treatment groups (0.455 ± 0.051 vs 0.318 ±0.045, P 〈 0.05). In comparison with the normal control, 50 and 100 mg/L grape procyanidins significantly stimulated cell growth, with a better effect observed with 100 mg/L grape procyanidins. CONCLUSION: Grape procyanidins inhibit the hepatocyte damage induced by ethanol and carbon tetrachloride, and stimulate normal hepatocyte proliferation. 展开更多
关键词 Grape procyanidin free radical Cell proliferation Apoptosis HEPATOCYTE
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Effects of total soy saponins on free radicals in the quadriceps femoris,serum testosterone,LDH,and BUN of exhausted rats 被引量:8
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作者 Zhigang Liu Ruixin Nie +3 位作者 Yun Liu Zhouhong Li Chenxi Yang Zhengying Xiong 《Journal of Sport and Health Science》 SCIE 2017年第3期359-364,共6页
Purpose:The aim of this study was to investigate the impact of total soy saponins(TS) on the free radical metabolism from the quadriceps femoris muscle,serum testosterone,lactate dehydrogenase(LDH),and blood urea nitr... Purpose:The aim of this study was to investigate the impact of total soy saponins(TS) on the free radical metabolism from the quadriceps femoris muscle,serum testosterone,lactate dehydrogenase(LDH),and blood urea nitrogen(BUN) in rats exercised to exhaustion.Methods:A one-time exhausted treadmill exercise session was used.Sprague-Dawley rats were divided into 4 groups:a control group—animals receiving no TS and no exercise(NTSNE),animals receiving TS but no exercise group(TSNE),animals receiving no TS but exercised to exhaustion group(NTSE),and animals receiving TS and exercised to exhaustion group(TSE).The TSNE and TSE groups were fed TS at a dosage of 20 mg/kg body weight once per day for 2 weeks.The NTSE group was given a placebo,and the NTSNE group was not given any treatment.The NTSE and TSE groups were exercised at speed of 30 m/min on treadmill until exhausted.The exercise time and exercise distance were recorded when the rats became exhausted and the rats were then decapitated and anatomized immediately.A 10% homogenate of the quadriceps femoris tissue was prepared.The levels of superoxide dismutase(SOD),catalase(CAT),malondialdehyde(MDA),glutathione peroxidase(GSH-Px),glutathione reductase(GR),reduced glutathione(GSH),total antioxidant capacity(T-AOC),LDH,BUN,and serum testosterone were tested.Results:TS significantly increased the exercise time to exhaustion by 20.62%(p < 0.05).The MDA levels were decreased significantly in the TSNE group than in NTSNE group(p < 0.05);the T-AOC levels increased significantly in the TSNE group than in the other 3 groups(p < 0.01,p < 0.05,p < 0.05).The LDH activity significantly increased in the NTSE group than in TSNE group(p < 0.05).The BUN levels significantly increased in the NTSE group than in the other 3 groups(p < 0.01,p < 0.01,p < 0.05),and significantly increased in the TSE group than in NTSNE and TSNE groups(both p < 0.01).The serum testosterone levels increased significantly in the TSNE group than in the other 3 groups(all p < 0.01).SOD,CAT,GSH-Px,GR,and GSH were not statistically different among the groups.Conclusion:TS can significantly improve the exercised rats' serum testosterone level and antioxidant activity in their quadriceps femoris to varying degrees,decrease MDA and serum LDH and BUN levels,increase the exercise time,and delay the occurrence of the fatigue. 展开更多
关键词 Exercised rat free radical Quadriceps femoris Serum enzymes TESTOSTERONE Total soy saponins
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Lipophilic Enhance of Vitamin C Protective Activity Against Free-radical-induced Damage in vivo 被引量:5
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作者 LUOXu-yang LIUZai-qun +3 位作者 SUNYun-xiu SUIDa-yuan YUXiao-feng QUShao-chun 《Chemical Research in Chinese Universities》 SCIE CAS CSCD 2003年第4期428-431,共4页
A group of experimental rats under free radical damage are given various amounts of a lipophilic vitamin C(ascorbyl-6-laurate, VC-12), and its parent compound, vitamin C, respectively. It has been found that the effec... A group of experimental rats under free radical damage are given various amounts of a lipophilic vitamin C(ascorbyl-6-laurate, VC-12), and its parent compound, vitamin C, respectively. It has been found that the effects of 1 12 mmol/kg VC-12 on decreasing triglyceride(TG), total cholesterol(TC), low density lipoprotein cholesterol (LDL-c) and lipid peroxide(LPO), and increasing high density lipoprotein cholesterol(HDL-c) and superoxide dismutase(SOD) are similar to those of 2 27 mmol/kg vitamin C. In addition, VC-12(1 12 mmol/kg) can increase the prostacycline(PGI 2) and decrease the thromboxane(TXA 2) even better than vitamin C(2 27 mmol/kg). The above facts demonstrate that the antioxidative activity of VC-12 is higher than twice that of vitamin C. So, ascorbyl-6-laurate may be a novel antioxidant drug against free radical damage. 展开更多
关键词 ANTIOXIDANT free radical Ascorbyl-6-laurate Vitamin C Blood lipid metabolism in vivo
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DESIGN AND SYNTHESIS OF NOVEL CHIRAL IONIC LIQUIDS AND THEIR APPLICATION IN FREE RADICAL POLYMERIZATION OF METHYL METHACRYLATE 被引量:5
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作者 宛新华 《Chinese Journal of Polymer Science》 SCIE CAS CSCD 2003年第3期265-270,共6页
Two new chiral ionic liquids, 1 -((-)-menthoxycarbonylmethylene)-3-methylimidazolium hexafluorophosphateand 1-((-)-menthoxycarbonylmethylene)-3-hexadecylimidazolium hexafluorophosphate, were designed an d prepared. Th... Two new chiral ionic liquids, 1 -((-)-menthoxycarbonylmethylene)-3-methylimidazolium hexafluorophosphateand 1-((-)-menthoxycarbonylmethylene)-3-hexadecylimidazolium hexafluorophosphate, were designed an d prepared. Theirchemical structures were characterized by ~1H-NMR. Reverse atom transfer radical polymerization of methyl methacrylate(MMA) in these two ionic liquids was carried out using AIBN/CuCl_2/bipy as the initiating system. The resultant well-definedpolymethyl methacrylate (PMMA) was employed as a macroinitiator to induce the atom transfer radical polymerization ofmenthyl methacrylate (MnMA) in chlorobenzene, which yielded a PMMA-b-PMnMA diblock copolymer with narrow polydispersity. 展开更多
关键词 Chiral ionic liquids Reverse ATRP free radical polymerization Methyl methacrylate Menthyl methacrylate
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May Chronic Childhood Constipation Cause Oxidative Stress and Potential Free Radical Damage to Children? 被引量:4
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作者 JI-YUEWANG YE-LINGWANG +1 位作者 SHENG-LIZHOU JUN-FUZHOU 《Biomedical and Environmental Sciences》 SCIE CAS CSCD 2004年第3期266-272,共7页
Objective To investigate whether chronic childhood constipation (CCC) may cause oxidative stress and potential free radical damage to children, and to explore the mechanisms by which CCC may cause oxidative stress an... Objective To investigate whether chronic childhood constipation (CCC) may cause oxidative stress and potential free radical damage to children, and to explore the mechanisms by which CCC may cause oxidative stress and potential free radical damage to chronic constipation patients (CCPs). Methods Sixty CCPs and sixty healthy child volunteers (HCVs) whose ages, gender and others were matched for the CCPs were enrolled in a randomized controlled study, in which levels of vitamin C (VC) and vitamin E (VE) in plasma as well as activities of superoxide dismutase (SOD) and catalase (CAT) in erythrocytes were determined by spectrophotometric analytical methods. Results Compared with average values of the above biochemical parameters in the HCVs group, the average values of VC and VE in plasma as well as those of SOD and CAT in erythrocytes in the CCPs group were significantly decreased (P<0.0001). Linear regression and bivariate correlation analysis showed that with prolonged course of the CCPs, the levels of VC and VE in plasma as well as the activities of SOD and CAT in erythrocytes in the CCPs were decreased gradually (P<0.0001). Conclusion The findings in the present study suggest that chronic childhood constipation causes oxidative stress and potential free radical damage to children with chronic constipation. 展开更多
关键词 Chronic childhood constipation Oxidative stress free radicals free radical damage Antioxidant Antioxidase
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Free Radical Generation by Selenium Compounds and Their Prooxidant Toxicity 被引量:11
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作者 JULIAN E. SPALLHOLZ(Food and Nutrition, Texas Technology University,Lubbock, TX 79404, USA) 《Biomedical and Environmental Sciences》 SCIE CAS CSCD 1997年第2期260-270,共11页
Selemum (Se) and many of its compounds are among the most toxic of nutrients. Selenium toxicity was first described in range animals in the western United States in the 1930's which consumed' selenium accumula... Selemum (Se) and many of its compounds are among the most toxic of nutrients. Selenium toxicity was first described in range animals in the western United States in the 1930's which consumed' selenium accumulator' plants of the genus Astragalus, Xylorrhiza,Oonopsis, and Stanleya. Selenites and selenates from the soil accumulate in these plants primarily as methylated selenium compounds and plants evolve dimethyldiselenide and dimethyselenide.Dietary selenium, primarily as selenomethionine and selenocysteine for humans fulfill the dietary requirement for selenoenzymes and proteins. In humans and animals excessive dietary selenium may be toxic. In vitro, selenium compounds such as selenite, selenium dioxide and diselenides react with thiols, such as glutathione, producing superoxide and other reactive oxygen species. This catalytic reaction of selenium compounds with thiols likely accounts for selenium toxicity to cells ex vivo and in vivo where the major glutathione producing organ,the liver, is also the major target organ of selenium toxicity.Selenium enzymes and selenoethers that do not readily form a selenide (RSe-) anion and compounds such as Ebselen where selenium is sequestered, are not toxic. Methylation of selenium by both plants and animals serves to detoxify selenium by generating methylselenides. Alternatively, full reduction of Se to elemental selenium (Se0) as done by some bacteria and the formation of heavy metal selenides such as Ag2Se or Hg2Se, results in a non-catalytic nontoxic form of selenium.This catalytic prooxidant attribute of some selenium compounds appears to account for its toxicity when such activity exceeds plant and animal methylation reactions and antioxidant defenses. This prooxidant activity may also account for cellular apoptosis and may provide a useful pharmaceutical application for selenium compounds as antibacterial, antiviral, antifungal and anticancer agents 展开更多
关键词 free Radical Generation by Selenium Compounds and Their Prooxidant Toxicity GSH
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Biophoton emission, free radical and toxicity of benzene to aquatic biosystems 被引量:3
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作者 Wang Yingyan Wang Jiguang(Beijing Municipal Research institute of Environrnental Protection, Beijing 100037, China)Ma Yuqin +3 位作者 Su Zhen Zhang Zonglun,Zhao Kejian Zheng Yanzhen Liu Chengxiang(Institute of Biophysics. Chinese Academy of Sciences, Beijing 1 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 1996年第2期218-227,共10页
The observation on biophoton emission, free radical and toxicity of benzene to zebra fish and carp hepatic microsome has demonstrated that there is the corresponding relationship between them by means of 60 Coγ radio... The observation on biophoton emission, free radical and toxicity of benzene to zebra fish and carp hepatic microsome has demonstrated that there is the corresponding relationship between them by means of 60 Coγ radiolysis. Free radicals play a key role in this relationship. A common photon originates of two biosystems are the excited species including singlet and triplet molecules (1O2 and C=0) as well as hydrocyclohexadienyl radical.OH and so on. OH, to a certain extent, directly participates in photon emission and toxicity of benzene to aquatic biosystems.These are the conclusions, but these are also problems. With the solution of the latters,model established in this work could be expected that it will be favorable for the development of photon-toxicology. 展开更多
关键词 biophoton emission free radical BENZENE aquatic biosystems.
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Butein imparts free radical scavenging, anti-oxidative and proapoptotic properties in the flower extracts of Butea monosperma 被引量:3
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作者 ANURADHA SEHRAWAT VIJAY KUMAR 《BIOCELL》 SCIE 2012年第2期63-71,共9页
The flower of Butea monosperma(Lam.)(Fabaceae)has been used in traditional Indian medicine in the treatment of many ailments including liver disorders.To understand the pharmacological basis of its beneficial effects,... The flower of Butea monosperma(Lam.)(Fabaceae)has been used in traditional Indian medicine in the treatment of many ailments including liver disorders.To understand the pharmacological basis of its beneficial effects,the extracts of dried flowers in water,methanol,butanol,ethyl acetate and acetone were evaluated for free radical scavenging and pro-apoptotic activities in cell cultures(human hepatoma Huh-7 cell line and immortalized AML-12 mouse hepatocytes).Butrin and butein-the active constituents of flower extracts-were used as reference molecules.The levels of cell injury markers like lactate dehydrogenase,glutathione and lipid peroxidation and primary antioxidant enzymes glutathione S-transferase and catalase were also measured.The aqueous and butanolic extracts exhibited better 2,2-diphenyl-1-picrylhydrazyl scavenging and cytotoxic activities in hepatoma cells than in immortalized hepatocytes.Interestingly,butein inhibited 2,2-diphenyl-1-picrylhydrazyl radical better than butrin.The aqueous and butanolic extracts were further investigated for hepatoprotection against carbon tertrachloride-induced biochemical changes and cell death.Both extracts,just as butrin and butein,significantly reversed the cellular glutathione levels and lipid peroxidation,and glutathione–S-transferase activity.Lactate dehydrogenase leakage and cell death were also prevented.However,only butein revived the catalase activity.Thus,the butein content of Butea monosperma flower extracts is important for free radical scavenging activity,apoptotic cell death and protection against oxidative injury in hepatic cells. 展开更多
关键词 butrin CYTOTOXICITY HEPATOPROTECTION methanol extract free radical scavenging
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Free radical scavenging abilities of polypeptide from Chlamys farreri 被引量:2
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作者 韩志武 初晓 +3 位作者 刘成娟 王跃军 孙谧 王春波 《Chinese Journal of Oceanology and Limnology》 SCIE CAS CSCD 2006年第3期325-328,共4页
We investigated the radical scavenging effect and antioxidation property of polypeptide ex- tracted from Chlamys farreri (PCF) in vitro using chemiluminescence and electron spin resonance (ESR) methods. We examined th... We investigated the radical scavenging effect and antioxidation property of polypeptide ex- tracted from Chlamys farreri (PCF) in vitro using chemiluminescence and electron spin resonance (ESR) methods. We examined the scavenging effects of PCF on superoxide anions ( O?2 ), hydroxyl radicals (OH·), peroxynitrite (ONOO-) and the inhibiting capacity of PCF on peroxidation of linoleic acid. Our experiment suggested that PCF could scavenge oxygen free radicals including superoxide anions ( O2? ) (IC50 =0.3 mg/ml), hydroxyl radicals (OH·) (IC50 = 0.2 μg/ml) generated from the reaction systems and effectively inhibit the oxidative activity of ONOO- (IC50 = 0.2 mg/ml). At 1.25 mg/ml of PCF, the inhibi- tion ratio on lipid peroxidation of linoleic acid was 43 %. The scavenging effect of PCF on O?2 , OH· and ONOO- free radicals were stronger than those of vitamin C but less on lipid peroxidation of linoleic acid. Thus PCF could scavenge free radicals and inhibit the peroxidation of linoleic acid in vitro. It is an anti- oxidant from marine products and potential for industrial production in future. 展开更多
关键词 POLYPEPTIDE Chlamys farreri free radical ANTIOXIDANT CHEMILUMINESCENCE electron spin resonance (ESR)
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Effects of Cigarette Auxiliary Material Parameters on Release Amounts of Tar, CO and Free Radicals in Cigarette Mainstream Smoke 被引量:3
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作者 周胜 朱立军 +10 位作者 汪长国 冯广林 戴亚 杨文敏 周学政 邱光明 张艇 李朝荣 王耀 周志刚 丁为 《Agricultural Science & Technology》 CAS 2013年第2期324-328,共5页
[Objective] This study aimed to investigate the effects of cigarette auxiliary material parameters on release amounts of tar, CO and free radicals in cigarette mainstream smoke. [Method] The effects of cigarette paper... [Objective] This study aimed to investigate the effects of cigarette auxiliary material parameters on release amounts of tar, CO and free radicals in cigarette mainstream smoke. [Method] The effects of cigarette paper air-permeability, cigarette paper gram weight, filter rod pressure drop and filter tip ventilating strength parameters on the release amounts of tar, CO and free radicals in cigarette mainstream smoke were investigated by single factor experiment and orthogonal experiment. [Result] The cigarette paper air-permeability, filter rod pressure drop and filter tip ventilating strength showed significantly negative correlation with the release amounts of tar, CO and free radicals in cigarette mainstream smoke, to be specific, the cigarette paper air-permeability showed the greatest effect on the release amounts of tar and CO, filter tip ventilating strength showed the greatest effect on the release amounts of gaseous-phase free radicals and particulate-phase free radicals, while cigarette paper gram weight showed relatively slight effect on the release amounts of tar, CO and free radicals. Within the orthogonal experimental range, the optimal program is identified as cigarette paper airpermeability of 70 CU, filter rod pressure drop of 4500 Pa/unit, and filter tip ventilating strength of 60 CU. Compared to the results without optimization, the release amounts of tar, CO and free radicals after optimization were all reduced. [Conclusion] This study laid the foundation for the research of cigarette tar reduction and harm reduction. 展开更多
关键词 Cigarette auxiliary materials TAR CO free radical Orthogonal design
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The Collapse Intensity of Cavities and the Concentration of Free Hydroxyl Radical Released in Cavitation Flow 被引量:3
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作者 张晓冬 付勇 +1 位作者 李志义 赵宗昌 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2008年第4期547-551,共5页
Enhancing the chemical reaction processes by means of the energy released in the collapse of micro bubbles or cavities in the cavitation flow is a new research area. In the previous work, a new approach of measuring c... Enhancing the chemical reaction processes by means of the energy released in the collapse of micro bubbles or cavities in the cavitation flow is a new research area. In the previous work, a new approach of measuring concentration of free hydroxyl radicals induced in cavitation flow by using methylene blue as the indicator was developed and used to study concentration of free radical induced in Venturi cavitation flow under various experimental conditions. In the present research, the radial evolution of a cavity bubble and the corresponding collapse pressure in sonic cavitation field are obtained by solving three different bubble dynamics equations: Rayleigh equation, Rayleigh-Plesset equation and Gilmore equation. By comparing with the experimental data on the radial evolution of a cavity bubble in the literature, it is found that the predicted results by the Gilmore equation, which takes account of the compressibility of fluid in addition to the viscosity and interfacial tension, agree with the experimental ones better than those by other two equations. Moreover, the theoretically predicted collapse pressures are consistent with the concentration of the free hydroxyl radical induced in the experimental venture. Thus, the concentration of the liberated free hydroxyl radical not only influences the reaction rate but also is used as an available parameter for measuring collapse intensity of cavities. 展开更多
关键词 hydrodynamic cavitation collapse pressure numerical simulation free hydroxyl radical
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Effects of leukemia inhibitory factor and basic fibroblast growth factor on free radicals and endogenous stem cell proliferation in a mouse model of cerebral infarction 被引量:2
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作者 Weihui Huang Yadan Li +2 位作者 Yufeng Lin Xue Ye Dawei Zang 《Neural Regeneration Research》 SCIE CAS CSCD 2012年第19期1469-1474,共6页
The present study established a mouse model of cerebral infarction by middle cerebral artery occlusion, and monitored the effect of 25 tJg/kg leukemia inhibitory factor and (or) basic fibroblast growth factor admini... The present study established a mouse model of cerebral infarction by middle cerebral artery occlusion, and monitored the effect of 25 tJg/kg leukemia inhibitory factor and (or) basic fibroblast growth factor administration 2 hours after model establishment. Results showed that following administration, the number of endogenous neural stem cells in the infarct area significantly increased, malondialdehyde content in brain tissue homogenates significantly decreased, nitric oxide content, glutathione peroxidase and superoxide dismutase activity significantly elevated, and mouse motor function significantly improved as confirmed by the rotarod and bar grab tests. In particular, the effect of leukemia inhibitory factor in combination with basic fibroblast growth factor was the most significant. Results indicate that leukemia inhibitory factor and basic fibroblast growth factor can improve the microenvironment after cerebral infarction by altering free radical levels, improving the quantity of endogenous neural stem cells, and promoting neurological function of mice with cerebral infarction. 展开更多
关键词 leukemia inhibitory factor basic fibroblast growth factor endogenous neural stem cells free radical MALONDIALDEHYDE nitric oxide glutathione peroxidase superoxide dismutase NEUROPROTECTION
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"LIVING" FREE RADICAL SYNTHESIS OF NOVEL RODCOIL DIBLOCK COPOLYMERS WITH POLYSTYRENE AND MESOGEN-JACKETED LIQUID CRYSTAL POLYMER SEGMENTS 被引量:2
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作者 宛新华 屠迎峰 +1 位作者 张东 周其凤 《Chinese Journal of Polymer Science》 SCIE CAS CSCD 1998年第4期377-380,共4页
The synthesis of rod-coil diblock copolymers was achieved for the first time by TEMPO-mediated 'living' free radical polymerization of styrene and 2,5-bis [(4-methoxyphenyl)oxycarbonyl] styrene(MPCS). The blo... The synthesis of rod-coil diblock copolymers was achieved for the first time by TEMPO-mediated 'living' free radical polymerization of styrene and 2,5-bis [(4-methoxyphenyl)oxycarbonyl] styrene(MPCS). The block architecture of the two diblock copolymers thus prepared, MPCS-b-St(5400/2400) and MPCS-b-St(10800/8700), was confirmed by GPC, DSC studies and the formation of multimolecular micelles. (Author abstract) 10 Refs. 展开更多
关键词 TEMPO 'living' free radical polymerization rodcoil diblock copolymer mesogen-jacketed liquid crystal polymer
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