[en] The microflora of numerous samples of bandages was investigated before and after irradiation. The total nucleus and mould numbers, D₁₀ values, Gram values and the shape of the microbes were determined. To measure the radiation resistance the samples were irradiated with doses of 1-8 kGy. No infection could be observed in the samples irradiated with 8 kGy. Microbes of extremely high resistance could not be found, D₁₀ value exceeded 1 kGy in case of two bacteria. (V.N.)

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[en] Based on the experimentally determined radioresistance spectrum of the average microflora which constitutes the potential initial contamination, l7,l69 microbial colonies were divided into radioresistance groups and their survival rates were calculated. (author)

[en] The variability was examined of bacterial contamination of gauze towels (5x6 cm) sampled from the production line over a period of one year. Significant differences were found in the average number of microorganisms per one product. High mean values were found at the end of summer, during autumn, and at the beginning of winter (maximum of 8083.3 microorganisms per one product), while the most favourable results were recorded during spring months (an average of 492.5 in March). The distribution of germs was found relevant to the lognormal or exponential distribution of probabilities. The products were found contaminated mainly by gram-positive cocci and aerobic spores. Exposure to substerilization doses of 1 to 15 kJ/kg (0.1 to 1.5 Mrad) resulted in an experimental drop in the number of the remaining contaminated products depending on the dose. The higher the average number of microorganisms per 1 product, the higher dose was necessary to achieve 100% inactivation. In the sensitivity limit of the cultivation method used the growth of microorganisms was found inhibited by a dose as low as 13 kJ/kg. An assessment was made of the effects of radiation sterilization of sanitary products and aids in dehydrated and aerobic environments, and a sterilization dose of 25 kJ/kg (2.5 Mrad) was found to offer an appropriate guarantee of sterility as long as the average contamination rate was equal to 100 microorganisms and maximum rate to 1000 in one products, or in 1 g per an area of 1 m². More attention to checking and minimization the pre-sterilization contamination is recommended. (author)

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[en] The results of a series of investigations into the distributions of microbial contaminants on single-use hypodermic products prior to radiation sterilization are presented in this paper. For hypodermic needles it was possible to fit formal negative binomial distributions to the frequency of numbers of contaminants on high proportions of product items, and thus to identify counts which were atypically high ('spikes'). The distributions of microorganisms on normal production syringes and on syringes suspected of having been exposed to greater than normal opportunities for contamination could not be defined by simple formal mathematical distributions. It was concluded that 'spikes' exist as one of the normal events associated with the microbiological contamination of mass-produced hypodermic products and thus have to be taken into account when designing protocols to establish doses of radiation sufficient to attain desired minimum levels of sterility assurance. (author)

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[en] This paper presents a magnetically levitated electromagnetic vibration energy harvester based on magnet arrays. It has a nonlinear response that extends the operating bandwidth and enhances the power output of the harvesting device. The harvester is designed to be embedded in a hip prosthesis and harvest energy from low frequency movements (< 5 Hz) associated with human motion. The design optimization is performed using Comsol simulation considering the constraints on size of the harvester and low operating frequency. The output voltage across the optimal load 3.5kΩ generated from hip movement is 0.137 Volts during walking and 0.38 Volts during running. The power output harvested from hip movement during walking and running is 5.35 μW and 41.36 μW respectively.. (paper)

[en] Myoelectrical pattern classification is a crucial part in multi-functional prosthesis control. This paper investigates a discriminant Fourier-derived cepstrum (DFC) and feature-level post-processing (FLPP) to discriminate hand and wrist motions using the surface electromyographic signal. The Fourier-derived cepstrum takes advantage of the Fourier magnitude or sub-band power energy of signals directly and provides flexible use of spectral information changing with different motions. Appropriate cepstral coefficients are selected by a proposed separability criterion to construct DFC features. For the post-processing, FLPP which combines features from several analysis windows is used to improve the feature performance further. In this work, two classifiers (a linear discriminant classifier and quadratic discriminant classifier) without hyper-parameter optimization are employed to simplify the training procedure and avoid the possible bias of feature evaluation. Experimental results of the 11-motion problem show that the proposed DFC feature outperforms traditional features such as time-domain statistics and autoregressive-derived cepstrum in terms of the classification accuracy, and it is a promising method for the multi-functionality and high-accuracy control of myoelectric prostheses