Signal strength versus cuff length in nerve cuff electrode recordings

When a nerve cuff electrode is used for the recording of signals from peripheral nerves, cuff dimensions have to be chosen. Traditionally, the peak-to-peak amplitude of the single-fiber action potential (SFAP) is optimized through the choice of cuff diameter and cuff length. In this paper, the dependency of the root-mean-square (RMS) value of the nerve signal on the cuff dimensions was studied and compared with the peak-to-peak value of the SFAP. A simple approximation for signal optimization by cuff dimensioning is suggested. The results were obtained from modeled SFAPs and from the electroneurogram (ENG) created by superimposed SFAPs, obtained from an inhomogeneous volume conductor model. The results show that the RMS value of the nerve signal is considerably more sensitive to the cuff length than the SFAP peak-to-peak amplitude, and that the RMS of the ENG is a linear function of the fiber diameter.     

A Context-Aware User Interface for Wireless Personal-Area Network Assistive Environments

The daily life of people with severe motor system impairments is challenging and thus often subordinated to extensive external help; increasing their level of self-support is thus highly desirable. Recent advances in wireless communications, in particular in wireless personal-area networks, serve as technological enablers well suited for implementing smart and convenient assistive environments which can increase self-support. This paper presents the design and prototyping of a versatile interface for such wireless assistive environments. We propose a modular framework that can accommodate several wireless personal-area network standards. The interface is built upon this framework and is designed in such a way that it can be controlled by various types of input devices such as a touch screen or a tongue-control unit. The interface can automatically discover consumer appliances (e.g. Zigbee and Bluetooth enabled lights and computers) in the user’s environment and display the services supported by these devices on a user-friendly graphical user interface. A demonstrator is prototyped and experimental results show that the proposed interface is context-aware, i.e. it successfully detects available appliances, adapts itself to the changes that occur in the user’s environment, and automatically informs the user about these changes. The results also show that the proposed interface is versatile and easy to use, i.e. the user can easily control multiple devices by means of a browser menu. Hence, the proposed work illustrates how assistive technology based on wireless personal-area networks can contribute to improving the quality of life of motor system impaired persons.     

Efficient solutions for Mastermind using genetic algorithms

We present a new genetic algorithm for playing the game of Mastermind. The algorithm requires low run-times and results in a low expected number of guesses. Its performance is comparable to that of other meta-heuristics for the standard setting with four positions and six colors, while it outperforms the existing algorithms when more colors and positions are examined. The central idea underlying the algorithm is the creation of a large set of eligible guesses collected throughout the different generations of the genetic algorithm, the quality of each of which is subsequently determined based on a comparison with a selection of elements of the set.     

Modern Meal Patterns: Tensions Between Bodily Needs and the Organization of Time and Space

This article argues that a sound understanding of eating must include analyses of the relation between the experienced body and different dimensions of eating patterns, such as the rhythm of eating, the quality of the meal, and its social context. In a qualitative interview study carried out in Copenhagen, Denmark, the relationship between eating habits and immediate bodily experiences of hunger, satiety, and appetite was investigated through open-ended, in-depth interviews with 20 individuals representing a variety of socio-economic backgrounds. In everyday life, most interviewees had problems accommodating what they considered to be an ideal meal pattern, i.e. an eating routine meeting their cultural and bodily needs simultaneously. We argue that the prevailing cultural model of meal patterns is detached from, and in conflict with, modern social organization of time and space. The individual body has become the place where conflicting structures and demands in society are experienced; it is also the place where these conflicts are supposed to be solved.     

Physical properties of mammary secretions in relation to chemical changes during transition from colostrum to milk

We examined the physical and chemical changes in milk during early lactation, and how these changes were affected by leaving one quarter unmilked in either the first or second milking, with the purpose of discriminating between colostrum and normal milk. Milk samples were collected from each quarter of 17 cows during the first 5 d after calving and then after about 7 d and 14d. Samples were analysed for somatic cell count (SCC), fat, protein, casein, lactose, IgG1, colour, plasmin, pH and coagulation properties. Large variations occurred in both chemical and physical properties throughout the study period. Within six milkings, the concentration of casein decreased by 60%, IgG1 by 94%, and lactose increased by 34%. At milking number 6, rennet coagulation time was lowest and curd firmness was highest. The pH increased from 6.4 to 6.7 over the period of the experiment, and the colour changed from yellow (reddish) to white. Coagulation properties and the pH fell within the range of normal milk after five milkings. Measurement of colour and density appeared to be a potential method for detection of milk unsuitable for the dairy factory. Effects of omitting one quarter in one milking differed between milk components, but seemed to be of little importance to the physical properties.     

Cytokine expression in mice exposed to diesel exhaust particles by inhalation. Role of tumor necrosis factor

Background  

Particulate air pollution has been associated with lung and cardiovascular disease, for which lung inflammation may be a driving mechanism. The pro-inflammatory cytokine, tumor necrosis factor (TNF) has been suggested to have a key-role in particle-induced inflammation.     

Progress in emitter wrap-through solar cell fabrication on boron doped Czochralski-grown silicon

We report on RISE-EWT (Rear Interdigitated Single Evaporation-Emitter Wrap-Through) solar cells on full area (12.5×12.5 cm²) pseudo square boron doped Czochralski-grown silicon wafers. We investigate the main efficiency optimisation factors of these cells by investigating the dependence of RISE-EWT cell parameters on the base dopant concentration N_A. We furthermore detail the effects of large feature sizes in base and emitter regions at the rear of the solar cell and investigate these effects with particular attention to the edge regions. EWT solar cells typically exhibit rather low fill factors. However, our results show that the improved fill factors can be achieved by increasing N_A, which in return leads to optimised efficiency values. For our RISE-EWT solar cells made from boron doped Cz-Si wafers, this benefit is maintained even after light-induced degradation. Our investigation of edge area related effects shows the importance of proper cell design in these areas, leading to a further 2.8% absolute improvement in the fill factor. Combining increased base dopant concentration with optimised edge design, we achieve 19.0% efficiency on (12.5×12.5 cm²) boron doped Cz silicon wafers before light-induced degradation, resulting in 18.1% efficiency in the light-degraded state.     

Postprandial lipid responses of butter blend containing fish oil in a single-meal study in humans

The postprandial effects of a butter product containing fish oil were investigated in a single-meal, randomized crossover study with a commercial butter product as the control. Twelve healthy males consumed two test meals with (13)C-labelled cholesterol (45 mg) and either an interesterified butter blend with fish oil (352 mg n-3 long-chain PUFA (LCPUFA)) or the commercial butter blend. Blood samples were collected after the meals and in the fasting condition on the test day and the following morning, and were analysed for cholesterol absorption, plasma lipid profile and fatty acid composition. No significant difference in the postprandial plasma fatty acid composition was observed between the groups, neither difference in cholesterol absorption, plasma cholesterol or the cholesterol contents of plasma lipoproteins. The incorporation of fish oil in the butter resulted in a significant lower concentration of triacylglycerols in the plasma 2 h after the meal in comparison with the commercial butter blend (p = 0.02); there was, however, no significant difference 24 h after the meal. In conclusion, fish oil-enriched butter blend provides a source to increase the intake of n-3 LCPUFA in the population, but has no acute effect on cholesterol absorption and plasma cholesterol concentration in human.     

Artefact reduction with alternative cuff configurations

In nerve cuff electrode recordings of neural signals, the pick-up of interfering signals can be reduced by choosing appropriate cuff configurations. In the traditionally used tripolar configuration, short circuiting of the end electrodes is expected to reduce the field inside the cuff from interfering signals. A model study suggests that moving the end electrodes toward the center of the cuff reduces the pick-up of interfering signals. In this paper, these properties are studied in more detail using a rabbit model. In addition, a new cuff configuration is suggested, which has an additional set of short circuited end electrodes. The total improvement of signal-to-noise ratio in the new configuration as compared with the traditionally used tripolar configuration was 73% for muscle signals and 127% for the stimulus pulse.     

Occupational exposures and health among Danish farmers working in swine confinement buildings

In a cross-sectional study at 11 large pig-breeding farms various work-related exposures were measured. The purpose was to record several simultaneous exposures in relation to various work tasks. The concentration of total dust and respirable dust was 4.13 mg/m³ and 0.48 mg/m³ respectively. For all farmers the relative heart rate increase during work was 29% of maximal work capacity (±9.7%), indicating a high work load. Increased pulmonary ventilation causes a higher risk for deposition of dust in the airways. The total tonnage lifted per day was 4,725 kg and was considered to be high according to Danish guidelines. During 40% of the working time, the work was performed with a forward flexion of the back of more than 20°. The load on the back may be the cause of the high one-year prevalence of low back pain at 62%. The work task of feeding pigs was the task with the highest number of simultaneous exposures.