The [15N]methacetin liver function test characterizes multicomponent exposure of children in industrially polluted regions.

The [15N]methacetin urine test for assessing disturbances of the cytochrome P450-aided oxygenation of xenobiotics in the human liver has been approved in several environmental health studies. A recent longitudinal study of kindergarten children near chemical and mining companies undergoing fundamental restructuring showed high, seasonally fluctuating SO2 burden which was well correlated with alterations in the mean liver states of the children. At one point the correlation disappeared, together with indications of large amounts of chlorinated compounds overflowing locally at nighttime. This was finally proven by analyzing urine samples from the children for trichloroacetic acid (TCA). Chlorinated ethanes and ethenes-the precursors of TCA-seemed to dominate the air pollution and to affect the hepatic detoxification capacity. We concluded that the methacetin liver function test reflects multicomponent exposure, including acute monopolization by a dominant pollutant for a time.     

The [15N]Methacetin Liver Function Test Characterizes Multicomponent Exposure of Children in Industrially Polluted Regions

Abstract

The [¹⁵N]methacetin urine test for assessing disturbances of the cytochrome P₄₅₀-aided oxygenation of xenobiotics in the human liver has been approved in several environmental health studies. A recent longitudinal study of kindergarten children near chemical and mining companies undergoing fundamental restructuring showed high, seasonally fluctuating SO₂ burden which was well correlated with alterations in the mean liver states of the children. At one point the correlation disappeared, together with indications of large amounts of chlorinated compounds overflowing locally at nighttime. This was finally proven by analyzing urine samples from the children for trichloroacetic acid (TCA). Chlorinated ethanes and ethenes—the precursors of TCA—seemed to dominate the air pollution and to affect the hepatic detoxification capacity. We concluded that the methacetin liver function test reflects multicomponent exposure, including acute monopolization by a dominant pollutant for a time.     

Phytoremediation of Lead in Soil: Recent Applications and Future Prospects

Abstract

Lead is a very serious contaminant in soil because of its widespread previous application in residential, agricultural, and industrial environments combined with its severe impacts upon human health, particularly upon children. Phytoremediation is a nontraditional approach to remediate contaminated soil involving the use of green plants. Phytostabilization involves the use of plants to stabilize contaminants to reduce human exposure. Phytoextraction involves the use of plants to accumulate contaminants in aboveground shoots, which can be harvested to recycle or discard. Recent phytomediation work has indicated the importance of determining the chemical forms of lead present at a site to develop the most appropriate remediation strategy. Lead phytoextraction typically involves the addition of a chelating agent in order to increase the bioavailability of this contaminant. Because concerns have been raised regarding the persistence of chelating agents in the environment, several research teams have investigated the use biodegradable compounds for this application. It is anticipated that phytoremediation will continue to be a low-cost approach for the remediation of lead in soil.     

载氧环境下脉冲放电等离子体修复污染土壤体系中自由基的发射光谱

基于发射光谱检测方法的优越性以及在高级氧化降解体系中·OH和·O的重要作用,本研究采用发射光谱检测技术测定载氧环境下脉冲放电等离子体(pulsed discharge plasma, PDP)修复污染土壤体系中·OH和·O相对发射光谱强度的变化。研究建立了针-网式PDP修复污染土壤体系,利用光谱仪检测该PDP体系在载氧环境下所生成的·OH和·O的相对发射光谱强度。通过对比实验分别考察了不添加土壤、添加原土、添加有机污染土壤和添加有机-重金属复合污染土壤的PDP体系中·OH和·O的相对发射光谱强度变化,同时考察了脉冲峰值电压、电极间距和O₂体积流量变化对·OH和·O的相对发射光谱强度的影响。研究结果表明：添加土壤有利于放电的发生,进而提高了PDP体系中·OH和·O的生成;添加有机污染土壤的PDP体系中·OH和·O发射光谱强度较原土体系中低,证明了PDP体系中·OH和·O对有机物的氧化作用;重金属离子的加入对于PDP体系中有机物的降解有积极的促进作用。同时,脉冲峰值电压和O₂体积流量的增加有利于PDP体系中·OH和·O的产生,而电极间距的增加不利于PDP修复污染土壤体系中·OH和·O的生成。本研究在说明PDP用于污染土壤修复体系中·OH和·O的关键作用的基础上,分析了PDP用于污染土壤修复过程中体系主要因素变化对体系中主要自由基含量的影响规律。     

Testing a theory of aircraft noise annoyance: a structural equation analysis

Previous research has stressed the relevance of nonacoustical factors in the perception of aircraft noise. However, it is largely empirically driven and lacks a sound theoretical basis. In this paper, a theoretical model which explains noise annoyance based on the psychological stress theory is empirically tested. The model is estimated by applying structural equation modeling based on data from residents living in the vicinity of Amsterdam Airport Schiphol in The Netherlands. The model provides a good model fit and indicates that concern about the negative health effects of noise and pollution, perceived disturbance, and perceived control and coping capacity are the most important variables that explain noise annoyance. Furthermore, the model provides evidence for the existence of two reciprocal relationships between (1) perceived disturbance and noise annoyance and (2) perceived control and coping capacity and noise annoyance. Lastly, the model yielded two unexpected results. Firstly, the variables noise sensitivity and fear related to the noise source were unable to explain additional variance in the endogenous variables of the model and were therefore excluded from the model. And secondly, the size of the total effect of noise exposure on noise annoyance was relatively small. The paper concludes with some recommended directions for further research.     

Total annoyance from an industrial noise source with a main spectral component combined with a background noise

When living close to an industrial plant, people are exposed to a combination of industrial noise sources and a background noise composed of all the other noise sources in the environment. As a first step, noise annoyance indicators in laboratory conditions are proposed for a single exposure to an industrial noise source. The second step detailed in this paper involves determining total annoyance indicators in laboratory conditions for ambient noises composed of an industrial noise source and a background noise. Two types of steady and permanent industrial noise sources are studied: low frequency noises with a main spectral component at 100 Hz, and noises with a main spectral component in middle frequencies. Five background noises are assessed so as to take into account different sound environments which can usually be heard by people living around an industrial plant. One main conclusion of this study is that two different analyses are necessary to determine total annoyance indicators for this type of ambient noise, depending on the industrial noise source composing it. Therefore, two total annoyance indicators adapted to the ambient noises studied are proposed.     

宿州城市土壤重金属污染特征及其健康风险评价

选取宿州市不同功能区(工业区、商业区、车站附近、居民区以及城市绿地)采集表层土壤样品55个,利用XRF测定出土壤中重金属Cu、Zn、Pb、Cr、Mn、Ni的含量,并借助健康风险评价模型,分别评价了土壤重金属在不同暴露途径下的健康风险。结果表明,Cu、Zn、Pb和Cr的平均含量均超出安徽省土壤背景值,说明宿州城市土壤中已受到不同程度的重金属污染;工业区、商业区和车站附近土壤重金属含量普遍较高,Cu、Zn、Pb与交通运输、工业生产关系密切,Cr主要来源于工业废弃物排放,Ni则受到生活污染和交通污染的双重影响;土壤重金属的非致癌风险指数(HI)和致癌风险指数(Risk)均低于危害水平界限,未形成明显的健康风险。     

位移传感器仿真器设计

针对目前机载系统地面试验的要求,设计了一种简单、驱动能力强、通用性好的位移传感器仿真电路。运用模拟乘法器AD633完成基准载波信号幅度的调制,简化了硬件电路的复杂度;利用运算放大器的非线性反馈以及三极管的电流放大特性,大大提高了电路的带负载能力;使用基准电压和以及调节接口的设置提高了仿真电路的通用性。在某飞机飞行控制系统地面试验中的应用表明,该位移传感器仿真电路能够实现角位移传感器及线位移传感器信号的仿真,运行稳定、波形良好,有一定的推广意义。     

Limited damage of tissue mimic caused by a collapsing bubble under low-frequency ultrasound exposure

In this study, we investigated the bubble induced serious damage to tissue mimic exposed to 27-kHz ultrasound. The initial bubble radius ranged from 80 to 100 μm, which corresponded approximately to the experimentally-evaluated resonant radius of the given ultrasound frequency. The tissue mimic consisted of 10 wt% gelatine gel covered with cultured canine kidney epithelial cells. The collapsing bubble behaviour during the ultrasound exposure with negative peak pressures of several hundred kPa was captured by a high-speed camera system. After ultrasound exposure, a cell viability test was conducted based on microscopic bright-field images and fluorescence images for living and dead cells. In the viability test, cells played a role in indicating the damaged area. The bubble oscillations killed the cells, and on occasion detached layers of cultured cells from the gel. The damaged area was comparable or slightly larger than the initial bubble size, and smaller than the maximum bubble size. We concluded that only a small area in close proximity to the bubble could be damaged even above transient cavitation threshold.     

0.8W/80K直线驱动斯特林制冷机的研制

介绍了一种 0 .8W/ 80 K分置式斯特林制冷机。该制冷机采用当前国外先进的直线电机驱动 ,双活塞对称布置结构。该制冷机已通过军品所要求的环境试验 ,输入功率小于 4 0 W(DC)情况下 ,其 +6 0℃高温环境下制冷量≥ 0 .5 W/ 80 K ,带载 0 .5 W工况下 MTTF已突破 2 0 0 0小时。文中主要论述了其工作原理、结构特点、试验情况。     

地源热泵地埋管换热量的研究

地源热泵地埋管换热器的换热量,不仅直接关系到这一能源方式的可行与否,还对系统形式,运行管理方案产生重要的影响,因而对任何一个工程都必须尽可能精准地确定它.试验使用人工冷热源模拟空调负荷,对某医院的地源热泵地埋管分别进行了冬季和夏季工况的换热量测试.并将依据测试数据计算所得结果与理论计算结果进行比较,最终得到该工程可信的...     

Electrode activation of anode-supported SOFCs with LSM- or LSCF-type cathodes

Electrode activation of SOFCs refers to one or more processes, which generally occurs during a first period of usually not longer than 100 h of applying a constant electrical load, and is associated with a decrease of the area specific resistance. To study this effect in relation to different starting-up and test conditions in more detail, the electrochemical performance between 650 and 900 °C of two types of anode-supported single cells, one with an La_0.65Sr_0.3MnO₃ (LSM) and the other with an La_0.58Sr_0.40Co_0.2Fe_0.8O_3−δ (LSCF) cathode, was evaluated.Both types of cells, when heated to and reduced at 800 °C, showed a decrease of the area specific resistance during the first 70 h at 800 °C of exposure under constant electrical load. The initial area specific resistance of cells heated to and reduced at 900 °C was comparable with that of the cells reduced at 800 °C and exposed for 70 h at 800 °C under constant electrical load. In other words, electrode activation is much faster at 900 °C than at 800 °C.     

Community noise exposure and stress in children

Although accumulating evidence over the past two decades points towards noise as an ambient stressor for children, all of the data emanate from studies in high-intensity, noise impact zones around airports or major roads. Extremely little is known about the nonauditory consequences of typical, day-to-day noise exposure among young children. The present study examined multimethodological indices of stress among children living under 50 dB or above 60 dB (A-weighted, day-night average sound levels) in small towns and villages in Austria. The major noise sources were local road and rail traffic. The two samples were comparable in parental education, housing characteristics, family size, marital status, and body mass index, and index of body fat. All of the children were prescreened for normal hearing acuity. Children in the noisier areas had elevated resting systolic blood pressure and 8-h, overnight urinary cortisol. The children from noisier neighborhoods also evidenced elevated heart rate reactivity to a discrete stressor (reading test) in the laboratory and rated themselves higher in perceived stress symptoms on a standardized index. Furthermore girls, but not boys, evidenced diminished motivation in a standardized behavioral protocol. All data except for the overnight urinary neuroendocrine indices were collected in the laboratory. The results are discussed in the context of prior airport noise and nonauditory health studies. More behavioral and health research is needed on children with typical, day-to-day noise exposure.     

同轴电缆连续波电磁辐照的终端负载响应

为了揭示设备互连电缆在连续波电磁辐照条件下的耦合响应规律,以典型射频同轴电缆为受试对象,将电缆终端连接的设备（系统）等效为负载,通过对其进行连续波电磁辐照效应试验研究,分析了受试电缆长度、终端负载状态等对同轴电缆终端负载响应规律的影响。结果表明:同轴电缆对电磁辐照响应具有选频特性,终端负载响应电压的峰值出现在电缆相对长度为1/2整数倍的频点;同轴电缆受到连续波电磁辐照后,感应皮电流通过转移阻抗转化为芯线与屏蔽层之间的差模感应电压,而这一感应电压源的内阻就是同轴电缆的特性阻抗;同轴电缆终端负载阻值的变化不会对其连续波辐照响应曲线的变化规律产生影响,终端负载与等效感应电压源内阻上的电压响应满足分压原理; 同轴电缆皮电流处于谐振状态时,两波节之间的分布感应电压同向,可等效为一个感应电压源,对同轴电缆终端负载响应起直接作用的电压源是最靠近终端负载的等效感应电压源。     

Study of stress-induced velocity variation in concrete under direct tensile force and monitoring of the damage level by using thermally-compensated Coda Wave Interferometry

In this paper, we describe an experimental study of concrete behavior under a uniaxial tensile load by use of the thermally-compensated Coda Wave Interferometry (CWI) analysis. Under laboratory conditions, uniaxial tensile load cycles are imposed on a cylindrical concrete specimen, with continuous ultrasonic measurements being recorded within the scope of bias control protocols. A thermally-compensated CWI analysis of multiple scattering waves is performed in order to evaluate the stress-induced velocity variation. Concrete behavior under a tensile load can then be studied, along with CWI results from both its elastic performance (acoustoelasticity) and plastic performance (microcracking corresponding to the Kaiser effect). This work program includes a creep test with a sustained, high tensile load; the acoustoelastic coefficients are estimated before and after conducting the creep test and then used to demonstrate the effect of creep load.     

大型通用静力试验平台研制与应用

为了验证大型结构体的设计合理性和产品可靠性,掌握结构体负荷承载能力,给出科学评价依据和指导意见,需要科学有效的试验手段为受试对象施加载荷,获取结构体应变、位移等信息,为力学分析提供必要数据支撑。分析了试验平台的主要功能需求,研究了由荷载测控系统、应变测量系统、位移观测系统、试验管理系统和图像监控系统组成的试验平台方案,重点论述了平台的核心关键技术,通过具体应用实例和试验数据,指出了试验平台的应用领域及所能解决的实际问题,最后总结了试验平台的特点和意义。     

The effects of environmental and classroom noise on the academic attainments of primary school children

While at school children are exposed to various types of noise including external, environmental noise and noise generated within the classroom. Previous research has shown that noise has detrimental effects upon children's performance at school, including reduced memory, motivation, and reading ability. In England and Wales, children's academic performance is assessed using standardized tests of literacy, mathematics, and science. A study has been conducted to examine the impact, if any, of chronic exposure to external and internal noise on the test results of children aged 7 and 11 in London (UK) primary schools. External noise was found to have a significant negative impact upon performance, the effect being greater for the older children. The analysis suggested that children are particularly affected by the noise of individual external events. Test scores were also affected by internal classroom noise, background levels being significantly related to test results. Negative relationships between performance and noise levels were maintained when the data were corrected for socio-economic factors relating to social deprivation, language, and special educational needs. Linear regression analysis has been used to estimate the maximum levels of external and internal noise which allow the schools surveyed to achieve required standards of literacy and numeracy.     

Internal radiocesium contamination of adults and children in Fukushima 7 to 20 months after the Fukushima NPP accident as measured by extensive whole-body-counter surveys

The Fukushima Dai-ichi NPP accident contaminated the soil of densely-populated regions in Fukushima Prefecture with radioactive cesium, which poses significant risks of internal and external exposure to the residents. If we apply the knowledge of post-Chernobyl accident studies, internal exposures in excess of a few mSv/y would be expected to be frequent in Fukushima.Extensive whole-body-counter surveys (n = 32,811) carried out at the Hirata Central Hospital between October, 2011 and November, 2012, however show that the internal exposure levels of residents are much lower than estimated. In particular, the first sampling-bias-free assessment of the internal exposure of children in the town of Miharu, Fukushima, shows that the ¹³⁷Cs body burdens of all children (n = 1,383, ages 6–15, covering 95% of children enrolled in town-operated schools) were below the detection limit of 300 Bq/body in the fall of 2012. These results are not conclusive for the prefecture as a whole, but are consistent with results obtained from other municipalities in the prefecture, and with prefectural data.