铈对原代肝细胞内NOS和NO的影响

研究了Ce3+对肝细胞中一氧化氮(NO)和一氧化氮合酶(NOS)的影响.结果表明,Ce3+能使肝细胞中NO含量和NOS活性增加.提示Ce3+有可能影响cGMP信号系统.     

一氧化氮在脱落酸和黑暗诱导蚕豆气孔关闭中的作用

[目的]研究一氧化氮(NO)在脱落酸(ABA)和黑暗诱导的蚕豆(Vicia faba)气孔关闭中的作用.[方法]以蚕豆叶片下表皮为材料,借助表皮条分析和激光扫描共聚焦显微镜技术对NO在ABA和黑暗诱导的气孔关闭中的作用进行了探索.[结果] ABA和黑暗都能诱导蚕豆气孔关闭,而且ABA和黑暗诱导都能提高保卫细胞胞质内的NO水平.NO专一性清除剂2,4-羧基苯-4,4,5,5-四甲基咪唑-1-氧-3-氧化物(cPTIO)、一氧化氮合酶(NOS)抑制剂NG-氮-L-精氨酸-甲酯(L-NAME)能够大大抵消ABA和黑暗诱导气孔关闭的效应,并能阻断ABA和黑暗诱导的气孔保卫细胞内NO水平的提高,表明NO是ABA和黑暗诱导蚕豆气孔关闭的共同信号分子.[结论]该研究可为探索保卫细胞信号转导网络积累一定的资料,并为提高植物抗逆能力和促进农业生产提供理论依据.     

黄颡鱼不同器官过氧化氢酶活性比较

[目的]比较黄颡鱼不同器官中过氧化氢酶活性.[方法]采用不连续聚丙烯酰胺凝胶电泳法和钼酸铵比色法,测定黄颡鱼6种组织(心脏、肝脏、鳃、肠、眼、肌肉)中过氧化氢酶的活性,并对各器官的酶活性进行比较.[结果]2种测定方法得到的过氧化氢酶活性具有一致性,且黄颡鱼6种组织的过氧化氢酶活性,由大到小依次为心脏、肝脏、鳃、肠、眼、肌肉.[结论] 黄颡鱼的过氧化氢酶活性,存在明显组织差异性.     

Ce(NO3)3对大鼠内脏组织和大脑一氧化氮及合成酶的影响

本文研究了硝酸铈对大白鼠内脏组织、大脑及骨骼肌中一氧化氮、一氧化氮合成酶的影响。结果显示 ,腹腔注射高浓度的稀土后 ,大鼠肝脏、心脏、肾脏、骨骼肌中一氧化氮、一氧化氮合成酶的水平明显增加 ,注射低浓度的稀土后 ,肝脏、肾脏内一氧化氮的量显著增加。提示稀土能够广泛影响机体一氧化氮、一氧化氮合酶的水平 ,一氧化氮有可能参与了稀土的中毒过程。     

一氧化氮对汞胁迫下小麦种子萌发及抗氧化代谢的影响

[目的]研究一氧化氯(NO)促进汞胁迫下小麦种子的萌发及其对萌发过程中氧化胁迫的缓解效应.[方法]采用不同浓度的HgCl2模拟重金属汞胁迫梯度处理小麦种子,以小麦种子发芽率达到对照的50%时,为汞胁迫对小麦种子萌发的半抑制浓度;以硝普钠(SNP)作为NO的供体,预处理小麦种子12 h后,置于半抑制浓度的汞胁迫条件下,研究小麦种子的发芽状况,探查种子中淀粉酶和蛋白水解酶的活性变化,以及过氧化氢酶(CAT)活性、脯氨酸和丙二醛(MDA)含量3个抗氧化指标的变化.[结果]NO供体SNP能显著促进汞胁迫下小麦种子的萌发,经SNP预处理的小麦种子中淀粉酶和蛋白水解酶的活性明显高于对照:SNP预处理能明显促进汞胁迫下小麦种子中CAT活性的上升,上调脯氨酸的水平,降低脂质过氧化产物MDA的含量.[结论]NO供体SNP能促进小麦种子萌发与幼苗的生长,并提高小麦种子的抗氧化能力.     

中草药添加剂对断奶仔猪抗氧化功能指标的影响

[目的]探讨中草药饲料添加荆对断奶仔猪抗氧化功能的影响,为中草药添加剂的利用及推广提供参考依据.[方法]选用48头体重相近的断奶仔猪,随机分为试验Ⅰ组(对照组)、试验Ⅱ组、试验Ⅲ组和试验Ⅳ组4个组.在饲喂中草药添加剂后第7、第14和第21天分别采取血液进行抗氧化功能指标的测定.[结果]试验IV组的血清超氧化物歧化酶(SOD)活性和谷胱甘肽酶(GSH-Px)活性在整个试验期间高于其他试验组,尤其在第7天时的差异显著或极显著(P<0.05或P<0.01).且GSH-Px活性随日龄的增加呈先降后升的变化;丙二醛(MDA)含量,在第7和第14天时,试验Ⅳ组低于其他组,差异极显著(P<0.01),在第21天时各组间无显著差异;试验Ⅳ组的一氧化氮(NO)含量显著低于其他组(P<0.05),并随着日龄增加,各组的NO含量均呈下降趋势.[结论]中草药添加剂能提高断奶仔猪抗氧化功能.     

中草药红景天对冷应激断奶仔猪生理机能的影响

[目的]探索中草药红景天对断奶仔猪抗冷应激的机理.[方法]选用25日龄断奶的大约克仔猪96头为试验动物.随机分成4组,慢性冷应激温度为(12±1)℃达14 d,将红景天粉碎后添加断奶仔猪的饲料中,添加量为饲料量的0.5%、1.0%和1.5%,饲喂14d后测定奶仔猪体增重,并测定猪体内一氧化氮(NO)含量、谷胱甘肽过氧化物酶(GSH-Px)活性及白细胞和红细胞数量等指标,研究红景天对冷应激断奶仔猪生理机能的影响.[结果]冷应激的大约克仔猪各试验组应用红景天后,NO含量明显降低,GSH-Px活性及白细胞和红细胞的数量明显升高,猪只体重及平均日增重也较对照组有显著升高.[结论]中草药红景天对冷应激的断奶仔猪有良好的促生长及抗病能力,添加量以饲料量的1.0%为宜.     

铈对鲤鱼生长性能及对脑组织抗氧化性和神经活动相关生化指标的影响

基础饲料中添加0、20 mg·kg-1、42 mg·kg-1、65 mg·kg-1的硝酸铈,饲喂鲤鱼60 d,研究了铈对鲤鱼生长性能、营养状况及对脑组织抗氧化性和神经活动相关生化指标的影响。结果表明,20 mg·kg-1、42 mg·kg-1的Ce(NO3)3能显著促进鲤鱼的生长,显著提高鱼体蛋白质和脂肪含量,显著降低饵料系数,在实验剂量范围内,42 mg·kg-1为最佳添加量。与对照组相比,20 mg·kg-1组过氧化氢酶(CAT)活性显著升高,42 mg·kg-1、65 mg·kg-1组CAT活性极显著降低,而20 mg·kg-1、42 mg·kg-1、65 mg·kg-1组鲤鱼脑超氧化物歧化酶(SOD)、单胺氧化酶(MAO)、一氧化氮合酶(NOS)活性、抗超氧阴离子自由基及抗羟离子自由基能力和丙二醛(MDA)含量无显著性变化,钙调神经磷酸酶(Ca N)活性却显著升高。研究还表明,与对照组相比,20 mg·kg-1组胆碱酯酶(CHE)活性极显著降低,65 mg·kg-1组谷胱甘肽过氧化物酶(GSH-PX)活性显著升高,一氧化氮(NO)含量显著降低。     

烧烤食品和啤酒对大鼠肝脏抗氧化系统的影响

[目的]为促进人们科学饮食提供参考.[方法]用烧烤食品和啤酒喂养大鼠,以非烧烤食品和纯净水喂养的大鼠为对照组,利用分光光度法对烧烤食品和啤酒对大鼠肝脏超氧化物歧化酶(SOD)活性、过氧化氢酶(CAT)活性、清除·OH自由基能力、还原力及丙二醛(MDA)含量影响进行分析.[结果]烧烤食品和啤酒会降低大鼠肝脏抗氧化能力,其中SOD活性极显著降低,CAT活性显著降低,清除·OH自由基能力和还原力减弱,但与对照差异不显著,MDA含量极显著增加.[结论]大量食用烧烤食品和啤酒会使肝脏抗氧化能力减弱,氧化性损伤增加,因此应适当减少食用烧烤和啤酒,同时补充一些天然抗氧化剂有益于健康.     

氨氮胁迫对泥鳅不同组织SOD和GSH-PX活性的影响

[目的]研究氨氮胁迫对泥鳅肌肉、肝脏、鳃组织中超氧化物歧化酶(SOD)与谷胱甘肽过氧化物酶(GSH-PX)活性的影响.[方法]采用生态毒理学方法,在淡水中分别添加NH4Cl 0、50、150、250、450 mg/L,并分组.测定21 d内泥鳅肌肉、肝脏、鳃组织中的SOD和 GSH-PX活性,并对数据进行分析.[结果]低浓度组(50、150 mg/L)在氨氮胁迫2 d和7 d时,泥鳅肝脏、鳃SOD和 GSH-PX活性,随胁迫浓度的升高和胁迫时间的延长逐渐升高,14 d和21 d时,逐渐降低.但250 mg/L组和450 mg/L组SOD和 GSH-PX活性随胁迫浓度的升高一直呈现下降趋势.与肝脏和鳃组织相比,肌肉组织内SOD和 GSH-PX对氨氮胁迫的反应比较滞后.[结论]氨氮对泥鳅3种组织的SOD和 GSH-PX活性均有显著影响.     

Nitric Oxide Emissions from Engineered Soil Systems

Sophisticated laboratory equipment and procedures are developed and used in controlled experiments to measure nitric oxide (NO) emissions ranging from 42 to 75 ng N∕m2?s from sludge-amended soil of concern to environmental engineers because nitric oxide emitted to the troposphere is a precursor to troublesome ozone formation and also of concern to agricultural engineers because valuable nitrogen as fertilizer is lost from the soil. Water-filled pore space is confirmed to be of critical importance to NO flux, and the upper layers of soil are determined to contribute the larger portion of the NO fluxing from the soil to the troposphere. More than 42% of the total NO flux comes from the top 1 cm of soil, with NO contributions decreasing exponentially with soil depth and very little if any tropospheric NO contributed from soil at a depth of 20 cm or greater. The results are discussed in terms of microbiological, chemical, and soil transport processes that influence NO flux from sludge-amended soil.     

Nitric Oxide Reduction Performance of Automotive Palladium Catalysts

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Nitric Oxide Emissions from Fertilized and Biosolids-Amended Soil

Nitric oxide (NO) emissions from soil amended with municipal wastewater biosolids or mineral fertilizer can adversely impact ozone levels in the lower troposphere and are studied here. A comprehensive laboratory protocol was developed and conducted to consider the influence of biosolids-amended (BSA) soil and mineral-fertilizer-amended (MFA) soil, as compared with unamended soil, on NO emissions with varying temperature, moisture content, and pH. NO plays an important role in the formation of tropospheric ozone. Minimization of NO flux from soil is advantageous, protecting air quality as well as conserving valued nitrogen fertilizers. BSA and MFA soils were found to produce NO emissions over five times greater than unamended soils. Distinctions between NO flux from MFA and BSA soil cannot be made. NO flux from soils at pH 6.25 and 6.75 were not found to be statistically different. Soils with higher water-filled pore space (WFPS) and temperature are generally shown to produce greater quantities of NO within the range of temperature (15°–28°C) and WFPS (3–40%) studied.     

Soil Nitric Oxide Emissions from Nitrification and Denitrification

A silty loam soil treated with 1-allyl-2-thiourea as an inhibitor of autotrophic nitrification, and sulfide as an inhibitor of nitric oxide reductase in respiratory denitrification, was studied to evaluate the respective contribution of these two microbial processes to the nitric oxide (NO) flux from the soil. Soil samples were either unamended or amended with ammoniated fertilizer or biosolids from a wastewater treatment plant at an application rate of 100 lb-nitrogen∕acre. Water-filled pore space and temperature were maintained within respective ranges of 22 ± 2% and 22 ± 1°C. NO fluxes from unamended, chemically fertilized, and biosolids-amended soil samples increase in that order, and autotrophic nitrification accounts for 80, 84, and 92% of the NO flux, respectively. The suggested Jousset-Peirce index Ψ, which shows the contribution of respiratory denitrification with respect to heterotrophic nitrification and chemodenitrification, decreases by a factor of 3.3 and 5.6 from unamended to chemically fertilized soil samples and from unamended to biosolids-amended soil samples, respectively. An ancillary finding reveals the dramatic sensitivity of denitrification to the presence of sulfide.     

Refractory Oxide Coatings on Titanium for Nitric Acid Applications

Tantalum and Niobium have good corrosion resistance in nitric acid as well as in molten chloride salt medium encountered in spent fuel nuclear reprocessing plants. Commercially, pure Ti (Cp-Ti) exhibits good corrosion resistance in nitric acid medium; however, in vapor condensates of nitric acid, significant corrosion was observed. In the present study, a thermochemical diffusion method was pursued to coat Ta₂O₅, Nb₂O₅, and Ta₂O₅ + Nb₂O₅ on Ti to improve the corrosion resistance and enhance the life of critical components in reprocessing plants. The coated samples were characterized by XRD, SEM, EDX, profilometry, micro-scratch test, and ASTM A262 Practice-C test in 65 pct boiling nitric acid. The SEM micrograph of the coated samples showed that uniform dense coating containing Ta₂O₅ and/or Nb₂O₅ was formed. XRD patterns indicated the formation of TiO₂, Ta₂O₅/Nb₂O₅, and mixed oxide/solid solution phase on coated Ti samples. ASTM A262 Practice-C test revealed reproducible outstanding corrosion resistance of Ta₂O₅-coated sample in comparison to Nb₂O₅- and Ta₂O₅ + Nb₂O₅-coated sample. The hardness of the Ta₂O₅-coated Cp-Ti sample was found to be twice that of uncoated Cp-Ti. The SEM and XRD results confirmed the presence of protective oxide layer (Ta₂O₅, rutile TiO₂, and mixed phase) on coated sample which improved the corrosion resistance remarkably in boiling liquid phase of nitric acid compared to uncoated Cp-Ti and Ti-5Ta-1.8Nb alloy. Three phase corrosion test conducted on Ta₂O₅-coated samples in boiling 11.5 M nitric acid showed poor corrosion resistance in vapor and condensate phases of nitric acid due to poor adhesion of the coating. The adhesive strength of the coated samples needs to be optimized in order to improve the corrosion resistance in vapor and condensate phases of nitric acid.     

Kinetic Modeling of the Gas-Phase Oxidation of Nitric Oxide Using Hydrogen Peroxide

The use of hydrogen peroxide (H2O2) to enhance the oxidation of nitric oxide (NO) under postflame conditions in the presence or absence of sulfur dioxide (SO2) has been studied by means of chemical kinetic modeling and compared with pilot-scale experimental data. The experimental results were obtained from a nonisothermal reactor at atmospheric pressure with inlet temperatures in the range of 770–790?K. The CHEMKIN-II model with a kinetic mechanism from the literature was employed for this work. At the temperatures studied, H2O2 produces OH and HO2 radicals which enhance the oxidation of NO. The OH radical also helps oxidize SO2. The modeling results confirmed an optimum temperature of about 775?K where the NO conversion reached about 90% with an H2O2:NO molar ratio of 1:1. Conversion of NO2 to HNO3 was found to occur to a slight extent. Finally, the presence of SO2 was found to promote slightly the oxidation of NO to NO2.     

Nitric Oxide Emission and Soil Microbial Activities in Toluene Contaminated Soil

The purpose of this research is to consider a novel concept for measuring and monitoring (M&M) the presence and levels of contaminants in soil. Current M&M techniques include direct sensing for the target contaminant and the surrogate indicators of respired O2 and CO2. The method suggested here is based on nitric oxide (NO). It is an alternative M&M method that could become quicker, easier, more reliable, and less expensive than the other M&M methods being used currently. NO emission from toluene contaminated soil and soil microbial activity were investigated to understand the NO-toluene-soil microbial relationships using fluorescent in situ hybridization molecular technique combined by enzymatic method. The relationships have been analyzed by the comparison of experimental measurements coming from analysis of variance statistical analysis, referring to toluene concentrations. Relationships between NO emissions and the microbial activity were significantly correlated (P<0.01) with the level of toluene concentration and duration of toluene contamination. Thus, NO emissions are suggested as a useful indicator of microbial activity in toluene contaminated soils.     

Nitric Oxide Alleviates Oxidative Stress Caused by Lanthanum in Rice Leaves

The effect of NO on lanthanum-induced antioxidant activities in rice was evaluated. The results showed that the uptake and translocation of La from root to shoot were obviously inhibited by 10μmol·L^-1 sodium nitropmsside （SNP）, a donor of NO, in the seedlings grown in Mura B nutrient solution with 100μmol·L^-1 La. Although the content of ascorbate acid （AsA） were scarcely affected by La or NO in our experiment, La decreased significantly the activity of SOD and content of GSH, while promoted H202 content in leaves. Furthermore, NO blocked these La effects. Taken together, the results suggested that NO relieved La toxicity in rice. A possible role for NO effects on antioxidant activity was discussed.     

Central Nitric Oxide Synthase Inhibition Disrupts Maternal Behavior in the Rat.

Blocking nitric oxide (NO) production, by 3rd ventricle administration of a nitric oxide synthase (NOS) inhibitor, N(G)-nitro-L-arginine methyl ester (L-NAME; 250 μg/5 μl, postpartum [pp]) decreased milk ejections in Day 10 pp rats. On Day 4 pp, L-NAME treatment eliminated pup retrieval and at both stages of lactation suppressed maternal aggression. Fewer rats treated with L-NAME on Day 10 pp retrieved 4-day-old pups than controls, although all nursed older litters. Following exposure to a mobile intruder, Fos expression was lower in the medial preoptic area and the bed nucleus of the stria terminalis in L-NAME-treated rats than in controls but was lower in the medial amygdala only following exposure to an anaesthetized intruder. Thus, the elevated levels of NO observed in lactation may contribute to the mechanism(s) that mediate maternal behavior and aggression. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

辊道窑中焦炉煤气再燃脱硝的数值模拟研究

目前,工业炉的氮氧化物排放量不断增长,进行工业炉内脱硝技术研究具有重要意义.提出了在工业炉内进行再燃脱硝的设想,并对辊道窑内的再燃脱硝过程进行了数值模拟分析.结果表明:以焦炉煤气作为再燃燃料,其再燃率应控制在10%～20%范围内;再燃Ⅸ过量空气系数在0.9～0.8之间,主燃区过量空气系数在1.02～1.08之间时,对NOx排放控制效果最好.并提出了烧嘴布置方式的优化方案.