载铁颗粒活性炭吸附除铬的热动力学研究

该文通过吸附动力学实验及等温吸附实验,考察了在10℃～40℃的温度条件下载铁颗粒活性炭(IOCGAC)吸附Cr(VI)的热动力学性质。结果表明:准二级反应动力学模型及Langmuir等温吸附模型可分别较好地描述IOCGAC对Cr(VI)的吸附动力学及吸附等温线实验结果(R2>0.99);吸附速率及吸附容量随温度的增加而增加。吸附速率k从0.00022增加到0.00033,吸附容量从18.48mg/g增加到23.20mg/g。根据标准吉布斯自由能变(ΔG0<0)和标准反应焓变(ΔH0>0)值判断,IOCGAC对Cr(VI)的吸附是自发的、吸热的化学吸附反应。     

2型糖尿病患者血清一氧化氮水平与其慢性并发症及病程的关系

采用硝酸还原酶法测定了５０例２型糖尿病患者血清中一氧化氮（ＮＯ）的水平,并探讨其与糖尿病慢性并发症及病程的关系。结果显示：无并发症的糖尿病患者血清ＮＯ水平明显高于正常对照组和有并发症的糖尿病患者;同时还发现ＮＯ水平随病程的延长而逐渐降低。提示ＮＯ是２型糖尿病馒性并发症发生发展的一个重要因素。     

银基氧化物梯度复合材料的研究

通过粉末冶金法制备了银基AgZnO/AgZnO-CdO/AgCdO叠层材料和AgSnO2梯度触头材料,这种设计方法从功能梯度的角度出发,更准确地考虑到了电接触材料的实际工作情况。作为一种全新的电接触材料的设计方法,初步考察了两种复合材料的电导率、热导率及电侵蚀前后接触表面的形貌和元素成分分布情况。     

Correlation between endothelia cells activation and imbalance of cytokines in pulmonary hypertension of congenital heart disease

Objective To explore the correlation between endothelia cells activation and cytokines （ET-1, NO） levels in patients with pulmonary hypertension （PH）, and to discuss their roles in the development of PH. Methods Twenty patients with simple ventricular septal defect （VSD） were chosen as controls, and 30 patients with PH were studied. Plasma levels of ET-1 and NO were measured by radioimmunoassay or colorimetric method. Before cardiopulmonary bypass was established, the specimens from right lung were fixed with formaldehyde solution, embedded with paraffin and stained by SP immunohlstochemistry. Intercellular adhesion molecule-1 （ICAM-1） expression was measured through the determination of the light density with computer imaging technology. Results Compared with that of the patients with simple VSD, the light density of ICAM-1 and plasma level of ET-1 increased in patients with PH; but plasma level of NO decreased （P〈0.05）. Positive correlation was observed between ICAM-1 and ET-1/NO （P〈0.05）. Conclusion Endothelia cells activation and imbalance of ET-1/NO might play an important role in the development of PH.     

T-2毒素对软骨细胞合成一氧化氮的影响

目的探讨T-2毒素对软骨细胞合成一氧化氮(NO)的影响。方法胎儿软骨细胞体外培养,用MTT法检测软骨细胞存活率;用Griess重氮化法测定软骨细胞培养上清液中NO含量;用Western blot检测软骨细胞一氧化氮合酶(iNOS)的表达。结果T-2毒素在质量浓度在1-2 000μg/L的范围内,软骨细胞存活率对其呈较典型的浓度依赖关系和时间依赖关系,而且随着作用时间的延长,浓度依赖关系更为明显;T-2毒素刺激软骨细胞分泌NO和表达iNOS蛋白。结论T-2毒素引起的软骨细胞损伤和生长抑制与T-2毒素刺激软骨细胞表达iNOS蛋白和分泌NO增多有关。     

Seasonal study of dissolved CH4, CO2 and N2O in a shallow tidal system of the bay of Cádiz (SW Spain)

During 2004, 10 samplings were performed in order to measure dissolved methane (CH₄), carbon dioxide (CO₂) and nitrous oxide (N₂O) in the surface waters of Río San Pedro, a tidal creek in the salt marsh area of the Bay of Cádiz (SW Spain). The inner partvs of the creek is affected by the inputs coming from an intensive fish farm and the drainage of an extensive salt marsh area.Dissolved CH₄, CO₂ and N₂O concentrations ranged from 11 to 88 nM, 36 to 108 μM and 14 to 50 nM, respectively. Surface waters were in all cases oversaturated with respect to the atmosphere, reaching values of up to 5000% for CH₄, 1240% for CO₂ and 840% for N₂O. Dissolved CH₄, CO₂ and N₂O showed a significant tidal and seasonal variability. Over a tidal cycle, concentrations were always highest during low tide, which points to the influence of the inputs from the fish farm effluent and the drainage of the adjacent salt marsh area, as well as in situ production within the system. Dissolved CH₄, CO₂ and N₂O seasonal patterns were similar and showed maximum concentrations in summer conditions. Using four different parameterizations to calculate the gas transfer coefficients [Liss, P.S. and Merlivat, L., 1986. Air-sea exchange rates: introduction and synthesis. In P. Buat-Ménard (Ed.), The Role of Air-Sea Exchanges in Geochemical Cycling. Reidel, Dordrecht, The Netherlands, p. 113–127.; Clark, J.F., Schlosser, P., Simpson, H.J., Stute, M., Wanninkhof, R., and Ho, D.T., 1995. Relationship between gas transfer velocities and wind speeds in the tidal Hudson River determined by the dual tracer technique. In: B. Jähne and E. Monahan (Eds.), Air-Water Gas Transfer: AEON Verlag and Studio, Hanau, Germany, pp. 785–800.; Carini, S., Weston, N., Hopkinson, G., Tucker, J., Giblin, A. and Vallino, J., 1996. Gas exchanges rates in the Parker River estuary, Massachusetts. Biol. Bull., 191: 333–334.; Kremer, J.N., Reischauer, A. and D'Avanzo, C., 2003. Estuary-specific variation in the air-water gas exchange coefficient for oxygen. Estuaries, 26: 829–836.], the averaged air–water fluxes of CH₄, CO₂ and N₂O from the creek to the atmosphere ranged between 34 and 150 μmol CH₄ m^− 2 day^− 1, 73 and 177 mmol CO₂ m^− 2 day^− 1 and 24 and 62 μmol N₂O m⁻² day⁻¹, respectively.     

汽车尾气颗粒物的遗传毒性及其毒作用机理的研究

为了探讨汽车尾气颗粒物的遗传毒性及其毒作用机理，给小鼠腹腔注射柴油机尾气颗粒物有机提取物后，对其进行了骨髓微核实验及红细胞超氧化物歧化酶（ＳＯＤ）活性和肝组织过氧化脂质（ＬＰＯ）水平影响的研究。结果表明，染毒组小鼠微核阳性率与对照组相比明显升高，有显著性差异（Ｐ〈０．０１），且呈明显的剂量反应关系；染毒组小鼠ＳＯＤ活性下降及ＬＰＯ水平升高与对照组比有显著性差异（Ｐ〈０．０１），且呈明显的剂量反应关     

大鼠脑发育过程中神经型一氧化氮合酶的表达变化

目的用免疫组化方法探讨神经型一氧化氮合酶在大鼠脑发育过程中的表达变化。方法分别随机选取E12、E15、E18、P0、P5及P10期的SD大鼠,应用免疫组化方法,检测大脑皮层、纹状体及海马nNOS阳性细胞的密度。结果E12、E15及E18期大鼠脑组织未见nNOS阳性细胞;大脑皮层及纹状体区P0、P5及P10期均可见nNOS阳性细胞。nNOS阳性细胞密度,在P0、P5及P10期逐渐降低,两两比较,有显著性差异(P<0.05)。P0期海马偶见nNOS阳性细胞,P5期和P10期均可见较多nNOS阳性细胞,但nNOS阳性细胞密度P5和P10期之间无统计学差异(P>0.05)。结论胚胎期大鼠脑内nNOS染色呈阴性反应;生后大脑皮层及纹状体nNOS阳性细胞密度逐渐减小,海马nNOS阳性细胞密度则有所增加。     

石灰粉煤灰基层质量问题分析

石灰粉煤灰三渣作为路基基层,已被广泛应用。该文针对某项目的个别标段的路基基层,出现不均匀的起伏和沉陷现象,以及路面多处出现沥青混凝土破损的问题,做了初步的分析,并建议加强对SO3和游离氧化钙予以控制。