口服纳米银对大鼠的生物有效性及其体内分布的研究

由于独特的抗菌特性,纳米银(AgNP)在诸多领域得到广泛应用,但是其生物有效性、动物组织分布及排出尚不清楚。将聚乙烯吡咯烷酮包被的AgNP溶液按照10 mg kg^-1给雌性SD大鼠灌胃,采用ICP-MS检测SD大鼠组织、粪便及尿液中总银浓度。实验结果表明,AgNP通过小肠吸收后,可以通过血液循环快速分布在肝、肾、脾、肺、脑等靶器官。灌胃后1 h,大鼠各组织中总银浓度达到最大值(肝、肾、脾、肺、脑中银浓度分别为0.29 ± 0.13 mg kg^-1、0.23 ± 0.04 mg kg^-1、0.17 ± 0.05 mg kg^-1、0.11 ± 0.01 mg kg^-1、0.06 ±0.02 mg kg^-1),之后银浓度随时间降低直至和对照组无显著性差异。在灌胃途径下,AgNP对SD大鼠的有效性为8.5%,且73%的AgNP是通过粪便的途径排出体外。     

厌氧反应器系统动力学模型构建方法学研究

以系统动力学的基本概念、方法为基础提出了存在于变量之间的3种基本关系模式,并在此基础上提出针对复杂系统的分块建模理论.将以葡萄糖为进水基质的厌氧反应器划分为3个子系统.确定了该系统的系统结构图,在此基础上构建厌氧消化系统的SD模型.根据分块建模的优势及特点,对模型中的3个子系统采用不同的计算方式,通过对比模拟结果表明,SD模型静态模拟结果与实验数据、传统结构模型模拟结果之间的误差<10%,动态模拟结果与实际趋势一致,说明SD模型的模拟结果是可信的.根据其特性,对取消物化子系统的简化模犁的模拟结果进行分析,表明根据不同的研究目的,选择合适的模型结构是必要的,采用系统动力学的分块建模方法有利于模型的简化与升级、减少计算量、提高模型的计算速度.     

二氧化硫对大鼠肺泡巨噬细胞DNA的损伤作用

运用单细胞凝胶电泳技术(又称彗星实验)研究了SO2动式吸入对雄性Wistar大鼠肺泡巨噬细胞DNA的损伤作用。结果表明，在SO2浓度为28．6，57．3，114．4ms／m^3的动式吸入染毒条件下，雄性大鼠肺泡巨噬细胞DNA拖尾长度分别为7．59，12．39，21．22μm，表明SO2可引起大鼠肺泡巨噬细胞DNA损伤，且随SO2吸入浓度的增加而加剧，呈明确的剂量效应关系，这意味着SO2具有引起哺乳动物肺泡巨噬细胞DNA突变的潜在危险，会造成机体的非特异性吞噬功能和抗肿瘤免疫监视作用的损伤。     

Short-term Model of the Production of Construction Aggregates in Taiwan Based on Artificial Neural Networks

BACKGROUND: Taiwan's geography and limited stock of sandstone have caused sandstone resources to gradually decline to the point of exhaustion after long-term excavation. Moreover, the Taiwanese government has continuously increased the amount of land area near rivers that cannot be excavated to facilitate riverbed remediation and promote conservation of water resources. Accordingly, predicting and managing the annual production of construction aggregates in future construction projects, and dealing appropriately with some thorny problems, for instance, demand that excess supply, excessive excavation, unregulated excavation, and the consequent environmental damage, will significantly affect the efficient use of natural resources in a manner that accords with the national policy of Sustainable Development (SD). METHODS:. This study establishes an empirical model for forecasting the annual production of future construction aggregates using Artificial Neural Networks (ANN), based on 15 relevant socio-economic indicators, such as indicator of annual consumption of cement. A sensitivity analysis is then performed on these indicators. RESULTS AND DISCUSSION: This work applies ANN to estimate the annual production of construction aggregates; the estimates, the verification of the model and the sensitivity analysis are all acceptable. Furthermore, sensitivity analysis results indicate that the annual consumption of cement is the indicator that most strongly influences the production of construction aggregates, as well as whether construction waste can be recycled and steel structures can be used in buildings, helping to reduce the future production of construction aggregates in Taiwan. CONCLUSIONS: The elaborate prediction methodology presented in this study avoids some of the weaknesses or limitations of conventional linear statistics, linear programming or system dynamics. Additionally, the results not only provide a short-term prediction of the production of construction aggregates in Taiwan, but also provide a viable and flexible means of verifying quality certification of the production data of construction aggregates in the future by incorporating those relevant socio-economic indicators. RECOMMENDATIONS AND OUTLOOK: The continuity and quality of the database of relevant indicators used in this study should be closely scrutinized in order to ensure the SD means of exploiting resources.     

民航维修人员习惯性违章行为的SD建模研究

掌握习惯性违章行为形成过程中的反馈机制和发展规律可以为消除习惯性违章行为提供理论依据。基于系统动力学(SD)理论,建立了民航机务维修人员习惯性违章行为的动态模型,利用VENSIM软件模拟仿真。结果表明,惩罚力度从第1等级(惩罚力度由小到大分别对应1~10等级)到第6等级时,习惯性违章行为活跃水平依次减小,从第6等级到第10等级时,习惯性违章行为活跃水平依次增加。此外习惯性违章行为活跃水平对工作单卡的合理程度敏感性最强,组织应优先提高工作单卡的合理程度。     

基于SD模型的不停航施工情景下机场安全风险作用机理研究

以不停航施工为特定情景,构建SD模型对机场安全风险的发生及作用机理进行研究。首先采用鱼骨图识别不停航施工情景下的机场安全风险,得到不停航施工情景下的机场安全风险共包括22个关键影响因子;然后采用因果关系图分析安全风险的影响关系,并运用SD模型软件Vensim PLE构建不停航施工情景下的机场安全风险SD模型流图,分析风险的作用机理,得到各风险因子相互作用形成5个主要的风险回馈循环;最后从机场层面、政府层面、施工企业层面三方面着手,提出了具体管理建议。该研究丰富了不停航施工情景下的机场安全风险方面的理论研究,可为减少不停航施工情景下的机场安全风险、完善民用机场安全风险管理体系提供参考。     

Intervention of pentoxifylline on silica-induced inflammatory reaction and apoptosis

Pentoxifylline (PTX) is a clinically used drug mainly for peripheral circulation improvement. This drug also possesses potent anti-inflammatory effects and was found to inhibit acute lung injury induced by chemical agents in animal models. Since it is also a potential apoptosis enhancer, this study was designed to examine the influence of PTX on silica-induced lung inflammation and pulmonary leucocyte apoptosis. Male Wistar rats were intratracheally instilled with either silica dust suspension or saline and intraperitoneally injected with saline or PTX. These treatments continued for six weeks and all rats were then sacrificed to obtain bronchoalveolar lavage cells and lavage fluid. Data demonstrated that PTX attenuated silica-induced lung injury in the rat model and this attenuation may possibly be attributed to its role in the enhancement of pulmonary apoptosis. As a known clinically safe drug, PTX may thus have potential use in the treatment of human silicosis.     

Incidence of thyroid disease following exposure to polybrominated biphenyls and polychlorinated biphenyls, Michigan, 1974-2006

Thyroid hormones, which influence body metabolism and development, could be affected by persistent organic pollutants. We sought to examine the relationship between polybrominated biphenyls (PBBs) and polychlorinated biphenyls (PCBs) and thyroid disease. We employed incidence density sampling to perform a nested case control analysis of the Michigan Long-Term PBB Cohort. Cohort members (n = 3333) were exposed to PBBs through contaminated cattle feed in 1973-1974 and to PCBs through daily life. Those with detectable serum PBB and PCB concentrations at enrollment were categorized into tertiles of PBB and PCB exposure. Case-patients were cohort members answering “Yes” to “Has a healthcare provider ever told you that you had a thyroid problem?” during follow-up interviews; control-patients were cohort members answering “No”. We used odds ratios (OR) with 95% confidence intervals (CI) to compare odds of thyroid disease by PBB and PCB exposure and by various risk factors. Total cumulative thyroid disease incidence after 33 years was 13.9% among women and 2.6% among men. After adjusting for body mass index, we found no statistically significant differences in odds of any type of thyroid disease among women or men with elevated PBB or PCB exposure. Compared to control-patients, women with thyroid disease had increased odds of being overweight/obese (OR = 2.82, 95% CI: 1.94-4.11) and developing infertility (OR = 1.71, 95% CI: 1.08-2.69), diabetes (OR = 1.61, 95% CI: 1.04-2.51), or arthritis (OR = 1.71, 95% CI: 1.18-2.50) during follow-up. Additional research should explore potential associations between PBBs/PCBs and thyroid disease among children exposed in utero.     

水资源对区域社会经济发展的支撑能力研究--以济南市长清区为例

水资源支撑能力即在当前技术水平条件下,某一区域水资源对区域发展总体目标的支撑限度.该文以系统动力学理论为指导,对长清区水资源的支撑能力进行了分析.拟定出在水资源约束条件下的三个区域发展方案,即:(1)水资源投资控制;(2)工业增长速度控制;(3)污水回用率控制.仿真结果分析表明,以方案(3)的适用性较好,在水资源投资不断增加,投资比例趋于合理的情况下,水资源对社会经济发展的支撑能力将由2002年的0.98提高天2010年的1.0.     

中国区域可持续发展水平的时空分异初探

本文通过因子分析,建立了中国可持续发展的因子结构模型,指出：（1）社会经济发展呈现“丁”字型格局;（2）环境污染东、中部严重,西部较轻;（3）生态退化西重东轻,北重南轻;（4）中国“环境与发展”时序上大致呈现“U”字型规律,29个省市分别与“U”曲线的逆向非同速（加速）阶段、同向非同速（加速）阶段、同向非同速（减速）阶段在地域上联系起来。