Cleanup worker exposures to hazardous chemicals at a former nuclear weapons plant : piloting of an exposure surveillance system

Cleanup of former U.S. Department of Energy (DOE) nuclear weapons production facilities involves potential exposures to various hazardous chemicals. We have collaboratively developed and piloted an exposure database and surveillance system for cleanup worker hazardous chemical exposure data with a cleanup contractor at the Rocky Flats Environmental Technology Site (RFETS). A unique system feature is the incorporation of a 34-category work task-coding scheme. This report presents an overview of the data captured by this system during development and piloting from March 1995 through August 1998. All air samples collected were entered into the system. Of the 859 breathing zone samples collected, 103 unique employees and 39 unique compounds were represented. Breathing zone exposure levels were usually low (86% of breathing zone samples were below analytical limits of detection). The use of respirators and other exposure controls was high (87 and 88%, respectively). Occasional high-level excursions did occur. Detailed quantitative summaries are provided for the six most monitored compounds: asbestos, beryllium, carbon tetrachloride, chromium, lead, and methylene chloride. Task and job title data were successfully collected for most samples, and showed specific cleanup activities by pipe fitters to be the most commonly represented in the database. Importantly, these results demonstrate the feasibility of the implementation of integrated exposure database and surveillance systems by practicing industrial hygienists employed in industry as well as the preventive potential and research uses of such systems. This exposure database and surveillance system--the central features of which are applicable in any industrial work setting--has enabled one of the first systematic quantitative characterizations of DOE cleanup worker exposures to hazardous chemicals.

Medical tourism and health worker migration in developing countries

In developing countries of tourist destinations, an increase in medical tourism raises the wages in the medical tourism sector, thereby retaining skilled medical workers who otherwise leave the country. However, the expansion of medical tourism contracts the domestic healthcare services sector, causing lower labor productivity in the economy. Medical tourism can increase domestic welfare if the benefits from migration retention and tourism exports outweigh the losses in revenue and productivity declines.

Impact of grain microstructure on the heterogeneity of precipitation strengthening in an Al-Li-Cu alloy

The effect of grain microstructure on the age-hardening behavior is investigated on recrystallized and un-recrystallized Al-Cu-Li alloys by combining electron-backscatter-diffraction and micro-hardness mapping. The spatial heterogeneity of micro-hardness is found to be strongly dependent on the grain microstructure. Controlled experiments are carried out to change the pre-strain before artificial ageing. These experiments lead to an evaluation of the range of local strain induced by pre-stretching as a function of the grain microstructure and results in heterogeneous formation of the hardening T1 precipitates.

Urban social insurance and worker satisfaction in China: Implications for India

This paper draws on a unique survey of urban employees in Jiangsu that was designed to assist analysis of workers' satisfaction with the urban social insurance scheme in China, and sheds light on whether workers in the urban non-state sector are satisfied with the level of social insurance coverage and whether their perceptions compare favourably with workers in the state-owned sector. It also discusses the globalisation and social protection debate in India and draws implications for the Indian experience from both our perception research and China's experience with urban social insurance reform more generally.

A non-destructive test to assess the axial heterogeneity of in situ modified monoliths for HPLC

This paper describes a non-destructive "peak parking" protocol in order to assess the axial heterogeneity of an in situ modified monolithic column for high performance liquid chromatography; a "gradient stationary phase" was designed whereby the ligand density decreases along the length of the rod in the "forward flow" configuration. The results of multi-location peak parking demonstrated a consistent increase in peak variance from the 1 cm position of the column to the 9 cm location. This increase in band broadening supported the theory of a decreasing ligand density along the length of this gradient column. This is consistent with efficiency measurements performed in both the forward and reverse flow directions, with an improved efficiency (15% increase in N m^-1) in the reverse direction. These results are consistent with theoretical investigations into stationary phase gradients.

Fire severity and fire-induced landscape heterogeneity affect arboreal mammals in fire-prone forests

In fire-prone regions, wildfire influences spatial and temporal patterns of landscape heterogeneity. The likely impacts of climate change on the frequency and intensity of wildfire highlights the importance of understanding how fire-induced heterogeneity may affect different components of the biota. Here, we examine the influence of wildfire, as an agent of landscape heterogeneity, on the distribution of arboreal mammals in fire-prone forests in south-eastern Australia. First, we used a stratified design to examine the role of topography, and the relative influence of fire severity and fire history, on the occurrence of arboreal mammals 2-3 years after wildfire. Second, we investigated the influence of landscape context on the occurrence of arboreal mammals at severely burnt sites. Forested gullies supported a higher abundance of arboreal mammals than slopes. Fire severity was the strongest influence, with abundance lower at severely burnt than unburnt sites. The occurrence of mammals at severely burned sites was influenced by landscape context: abundance increased with increasing amount of unburnt and understorey-only burnt forest within a 1 km radius. These results support the hypothesis that unburnt forest and moist gullies can serve as refuges for fauna in the post-fire environment and assist recolonization of severely burned forest. They highlight the importance of spatial heterogeneity created by wildfire and the need to incorporate spatial aspects of fire regimes (e.g., creation and protection of refuges) for fire management in fire-prone landscapes.

Heterogeneity of miR-10b expression in circulating tumor cells

Circulating tumor cells (CTCs) in the blood of cancer patients are recognized as important potential targets for future anticancer therapies. As mediators of metastatic spread, CTCs are also promising to be used as € liquid biopsyto aid clinical decision-making. Recent work has revealed potentially important genotypic and phenotypic heterogeneity within CTC populations, even within the same patient. MicroRNAs (miRNAs) are key regulators of gene expression and have emerged as potentially important diagnostic markers and targets for anti-cancer therapy. Here, we describe a robust in situ hybridization (ISH) protocol, incorporating the CellSearch ® CTC detection system, enabling clinical investigation of important miRNAs, such as miR-10b on a cell by cell basis. We also use this method to demonstrate heterogeneity of such as miR-10b on a cell-by-cell basis. We also use this method to demonstrate heterogeneity of miR-10b in individual CTCs from breast, prostate and colorectal cancer patients.

Investigation of progress of reactions and evolution of radial heterogeneity in the initial stage of thermal stabilization of PAN precursor fibres

The relationship between process parameters and structural transformations in the fibres at each stage of the carbon fibre manufacturing process play a crucial role in developing high performance carbon fibres. Here we report a systematic method which uses the combination of Taguchi approach and scientific evaluation techniques to establish these relationships for the initial stage of thermal stabilization. Density, cyclization index and fraction of reacted nitriles of a precursor containing acrylonitrile, methacrylate and itaconic acid (AN/MA/IA) were used to assess the progress of stabilization in the fibres with respect to various combinations of process parameters. The extent of progress of stabilization improved with increase in temperature (from 225 to 235 °C) and time (from 12 to 24 min) whereas an opposite trend was observed with increase in the tension on the fibres from (1600-2550 cN). According to optical microscopy, radial heterogeneity was observed in the fibres treated at 235 °C. Interestingly, we were able to identify the existence of heterogeneous modulus distribution from skin to core of the precursor fibres which was further transferred to treated fibres. The overall radial modulus of treated fibres was higher than the precursor fibres. In contrast to the literature, the fracture morphology of the fibre samples indicated that initiation of crack is caused by surface defects rather than radial heterogeneity.