The use of continuous exposure data for predicting CTS in fish processing operators

Carpal tunnel syndrome (CTS) remains one of the most commonly reported and studied work related musculoskeletal disorders. Categorical representations of exposures has been critical in identifying associations between risk factors and CTS, however, quantification of exposure-response relationships require using continuous exposure data. Also, few interactions between risk factors, especially between risk factor categories, have been investigated. The objectives of this study were to investigate the utility of using continuous exposure data and to identify interaction effects of risk factors, both within and between risk factor categories, for predicting CTS. A cross sectional study was performed at a fish processing facility in which 53 participants were evaluated during normal task performance. Due to task asymmetry, each hand was considered separately, providing 106 hands for analysis. Direct measurement and a questionnaire were used to quantify exposures to common occupational and personal risk factors. Stepwise logistic regression analysis was performed to identify three models for predicting CTS and assess predictive ability using: occupational risk factors only (three-way interactions considered), personal risk factors only (two-way interactions considered), and a mixed model considering two-way interactions across risk factor categories and previously identified significant interactions. Models including only occupational or personal risk factors were moderately accurate overall (73% and 77% respectively), but were not sensitive in differentiating between CTS cases and non-cases (39% and 33% respectively). The mixed model was found to be accurate (88%) and sensitive (78%), though only one interaction effect was included. The results of this study illustrate the importance of using continuous exposure data, especially in job tasks where exposures to occupational risk factors is similar, when differentiating between high and low risk job tasks.     

A biosensing system based on extracellular potential recording of ligand-gated ion channel function overexpressed in insect cells

We have used outer cell potential measurement to record agonist-dependent cellular responses in cells engineered to express ligand-gated ion channels and grown on a microelectrode surface. Application of glutamate, a natural agonist, induced a complex and robust potentiometric response in cells expressing homomeric GluR-D glutamate receptor, but not in nonexpressing control cells. The response consisted of an initial decrease in outer potential followed by a transient increase and was not obtained for other amino acids devoid of agonist activity at glutamate receptors. Furthermore, the pharmacological agonist of the GluR-D receptor, kainate, also produced the potentiometric response whereas 6-cyano-7-nitroquinoxaline-2,3-dione, a competitive antagonist, was not active in itself but attenuated the responses to glutamate. The time course of the measured changes was slow, which may be partially due to the ligand being applied by free diffusion but may also reflect a contribution by secondary changes in the behavior of the cells. This novel approach should be applicable to other ligand-gated ion channels and holds promise as a cell-based biosensor for high-throughput drug screening and other applications.     

Characteristics of job rotation in the Midwest US manufacturing sector

Job rotation has been advocated as a suitable intervention to control work-related musculoskeletal disorders. However, little is known regarding the prevalence of job rotation, methods used to identify jobs for rotation or the benefits or limitations of job rotation. A web-based questionnaire was developed to survey job rotation practices from Midwest US manufacturing companies. Results indicated that 42.7% of the companies contacted used job rotation, where the median time for which they had used job rotation was 5 years. Job rotation was used mainly to reduce exposure to risk factors for work-related injuries and to reduce work related injuries, whereas supervisor decisions and ergonomic analyses were used to select jobs for the rotation scheme. Major limitations to successful implementation of job rotation included rotation of individuals with medical restrictions, decreased product quality and lack of jobs to rotate to. These findings suggest that further study is needed to determine if exposure to risk factors is reduced through current efforts.     

Testing attribute grammars for circularity

Summary The problem of deciding whether a given attribute grammar is noncircular is known to require exponential time for infinitely many grammars. Here the time requirement of a simple circularity test is analyzed. It is shown that the reason for the exponential time requirement is the number of graphs in a collection formed for every nonterminal. By practical experiments it is argued that for real grammars the number is very small. Therefore it is feasible to actually perform the circularity test in practice. Different techniques to improve the implementation of the circularity test are discussed, too.     

Integrated Amplifier Circuits for 60 GHz Broadband Telecommunication

Wide frequency bandwidth has been internationally allocated for unlicensed operation around the oxygen absorption frequency at 60 GHz. A power amplifier and a low noise amplifier are presented as building blocks for a T/R-unit at this frequency. The fabrication technology was a commercially available 0.15 m gallium arsenide (GaAs) process featuring pseudomorphic high electron mobility transistors (PHEMT). Using on-wafer tests, we measured a gain of 13.4 dB and a +17 dBm output compression point for the power amplifier at 60 GHz centre frequency when the MMIC was biased to 3 volts V_dd. At the same frequency, the low noise amplifier exhibited 24 dB of gain with a 3.5 dB noise figure. The AM/AM and AM/PM characteristics of the power amplifier chip were obtained from the large-signal S-parameter measurement data. Furthermore, the power amplifier was assembled in a split block package, which had a WR-15 waveguide interface in input and output. The measured results show a 12.5 dB small-signal gain and better than 8 dB return losses in input and output for the packaged power amplifier.     

Supporting visually impaired children with software agents in a multimodal learning environment

Visually impaired children have a great disadvantage in the modern society since their ability to use modern computer technology is limited due to inappropriate user interfaces. The aim of the work presented in this paper was to develop a multimodal software architecture and applications to support learning of visually impaired children. The software architecture is based on software agents, and has specific support for visual, auditory and haptic interaction. It has been used successfully with different groups of 7-8 year-old and 12 year-old visually impaired children. In this paper we discuss the enabling software technology and interaction techniques aimed to realize our goal and our experiences in the actual use of the system.     

渗透结晶型防水——如何选择并鉴定适当的产品系统以正确地使用

介绍了市场上各种水泥基渗透结晶型防水系统表层应用材料的种类和原理,分析了渗透结晶型材料的特点和优势,指导人们在防水工程中如何选择适当的防水材料。