Human Interindividual Variability in Susceptibility to Airborne Particles

Part of the explanation for the persistent epidemiological findings of associations between mortality and morbidity with relatively modest ambient exposures to airborne particles may be that some people are much more susceptible to particle-induced responses than others. This study assembled a database of quantitative observations of interindividual variability in pharmacokinetic and pharmacodynamic parameters likely to affect particle response. The pharmacodynamic responses studied included data drawn from epidemiologic studies of doses of methacholine, flour dust, and other agents that induce acute changes in lung function. In general, the amount of interindividual variability in several of these pharmacodynamic response parameters was greater than the variability in pharmacokinetic (breathing rate, deposition, and clearance) parameters. Quantitatively the results indicated that human interindividual variability of breathing rates and major pharmacokinetic parameters-total deposition and tracheobronchial clearance-were in the region of Log(GSD) = 0.1 to 0.2 (corresponding to geometric standard deviations of 10(.1)-10(.2) or 1.26-1.58). Deposition to the deep lung (alveolar region) appeared to be somewhat more variable: Log(GSD) of about 0.3 (GSD of about 2). Among pharmacodynamic parameters, changes in FEV1 in response to ozone and metabisulfite (an agent that is said to act primarily on neural receptors in the lung) were in the region of Log(GSD) of 0.2 to 0.4. However, similar responses to methacholine, an agent that acts on smooth muscle, seemed to have still more variability (0.4 to somewhat over 1.0, depending on the type of population studied). Similarly high values were suggested for particulate allergens. Central estimates of this kind of variability, and the close correspondence of the data to lognormal distributions, indicate that 99.9th percentile individuals are likely to respond at doses that are 150 to 450-fold less than would be needed in median individuals. It seems plausible that acute responses with this amount of variability could form part of the mechanistic basis for epidemiological observations of enhanced mortality in relation to ambient exposures to fine particles.     

浅析分词逻辑主谓关系一致的几种特殊情况

分析了作状语的分词逻辑主谓关系一致的三种例外情况 ,即在什么条件下作状语的分词逻辑主语可与句子的主语不一致 ,及其与悬垂结构之区别。     

复合吸水颗粒深部液流转向剂注入性研究

由于吸水网络与控制网络的互穿结构，复合吸水材料颗粒具有吸水膨胀速度可控、吸水后强度高的特点。通过填砂管模型、变径管模型研究了复合吸水颗粒深部液流转向剂的注入特性、吸水后在孔喉中的运移情况。实验结果表明：在粒径小于孔喉尺寸的前提下，未吸水膨胀前颗粒可以顺利注入；吸水后即使颗粒直径大于孔喉直径也可以通过拉伸变形顺利通过，通过后立即恢复原状。注入过程中填砂管渗透率降低，颗粒膨胀后渗透率进一步降低，颗粒膨胀后在驱替压力足够大的情况下依然可以在填砂管微孔中运移。     

柱状曲面容器内粒子图像测速中径向畸变校正方法

针对粒子图像测速（PIV）中速度矢量由于折射率引起的光学畸变进行了系统校正研究，提出了一种用于柱状曲面容器内PIV测量的径向光学畸变校正方法。并应用于泰勒一库埃特流测量的校正。     

带电颗粒悬浮液有效交流复电导率

本文将配置法应用于研究带电粒子悬浮液的有效交流复电导率．研究表明，在相当宽的粒子浓度范围内，配置方法十分有效．配置方法不受悬浮液中两相介质的介电系数相等这一条件的限制，从而为进一步研究带电颗粒悬浮液的宏观物理性质提供了一条有效的途径．     

机载雷达平台运动补偿技术

机载雷达，由于平台运动造成地杂波谱产生多普勒频移和展宽。在讨论机载雷达地杂波频谱特性基础上，分析比较了ＡＭＴＩ系统和ＡＤＰＣＡ系统的性能，这些系统均具有良好的地杂波抑制能力。计算机模拟结果表明双路ＡＤＰＣＡ系统具有极好的地杂波抑制能力，是一种优异的平台运动补偿技术。     

机载雷达组网导航定位误差仿真分析

机载雷达组网具有雷达组网和空中机动的综合优势.获取组网中载机导航定位的准确数据是目标定位的一个重要问题.文中对机载雷达组网时导航定位误差影响目标定位的误差机理进行了理论推导,重点对导航定位误差产生的目标定位误差进行了仿真分析,得出了两者之间的对应关系及导航定位误差产生的目标定位不一致性这一不可忽略的重要结论.     

试论语气词的语法特征及作用

语气的表达离不开语气词。语气词是语气系统中的一个重要组成部分,在语气表达上有着不可替代的作用。文章对语气词的语法特征、分类及表达作用进行了分析。     

Associations Between 1980 U.S. Mortality Rates and Alternative Measures of Airborne Particle Concentration

We analyzed the 1980 U.S. vital statistics and available ambient air pollution data bases for sulfates and fine, inhalable, and total suspended particles. Using multiple regression analyses, we conducted a cross-sectional analysis of the association between various particle measures and total mortality. Results from the various analyses indicated the importance of considering particle size, composition, and source information in modeling of particle pollution health effects. Of the independent mortality predictors considered, particle exposure measures related to the respirable and/or toxic fraction of the aerosols, such as fine particles and sulfates, were most consistently and significantly associated with the reported SMSA-specific total annual mortality rates. On the other hand, particle mass measures that included coarse particles (e.g., total suspended particles and inhalable particles) were often found to be nonsignificant predictors of total mortality. Furthermore, based on the application of fine particle source apportionment, particles from industrial sources (e.g., from iron/steel emissions) and from coal combustion were suggested to be more significant contributors to human mortality than soil-derived particles.     

新型气流分级机颗粒运动路径研究

模拟分析颗粒分级机流体里运动的颗粒运动路径在粉碎分级设备生产过程中具有重要意义。通过事先预测颗粒运动路径,一方面可以确保分级精度和质量,另一方面可以提高经济效益。为准确地反映在流体影响下颗粒的理化性质变化及边界条件,文章利用数值模拟预测了颗粒运动路径,根据模拟结果确定新型VS分级机关键几何尺寸。据此试制的样机运行试验表明,实际分级指标和模拟算法分级指标十分吻合。