Boisenboysen8529

Background Electromyographic (EMG) signals obtained from a contracted muscle contain valuable information on its activity and health status. Much of this information lies in motor unit potentials (MUPs) of its motor units (MUs), collected during the muscle contraction. Hence, accurate estimation of a MUP template for each MU is crucial. Objective To investigate the possibility of improving MUP template estimation using the wavelet denoising technique. Material and Methods In this analytical study, several MUP template estimators were developed by combining conventional estimation methods and wavelet denoising techniques. A MUP template was initially estimated using conventional methods such as mean, median, median-trimmed mean, or mode. Thereafter, it was post-processed using the wavelet denoising technique. Results Evaluation results of the studied estimators using 40 simulated EMG signals with a true template for each constituent MUP train showed that augmented wavelet- based template estimation methods are more reliable than conventional methods. However, on average, wavelet denoising was not much effective. Around 40 MUPs of a MU is sufficient to estimate its MUP template. Conclusions Although wavelet techniques are effective in EMG signal analysis, here wavelet denoising did not practically improve MUP template estimation. Considering computational simplicity and estimation error, the two methods median and median-trimmed mean are practical estimators that can provide a good estimation of a MUP template for a MU when approximately 40 MUPs are available. Nevertheless, the baseline noise level in the MUP templates estimated using the median-trimmed mean method is slightly lower than that in the templates estimated using the median method. Copyright © Journal of Biomedical Physics and Engineering.Background Muscle fatigue has been known to influence brain activity, but very little is known about how cortical centers respond to muscle fatigue. Objective This study was conducted to investigate the effects of muscle contraction and fatigue induced by two different percents of maximal voluntary contraction (MVC) on Electroencephalography (EEG) signals. selleck products Material and Methods In this quasi-experimental study, EEG signals were recorded from twenty-one healthy human subjects during three phases (rest, pre fatigue and post fatigue) contraction of Adductor pollicis muscle (APM) at 30% and 70% MVC. The mean powers of EEG bands (alpha, beta and gamma) were computed offline in the frequency domain. Results None of the three phases with each percent of MVC revealed significant differences for all bands (p>0.05). Comparison of two hemispheres showed that right hemisphere gamma band activity was enhanced during pre-fatigue state at 30% MVC (p= 0.042) and post-fatigue state at 70% MVC (p= 0.028). Right hemisphere beta band activity also increased prominently at 70% MVC in post-fatigue condition (p = 0.030). Conclusion These results suggest muscle contraction and fatigue at 30% and 70% MVC have no significant effect on EEG activity, but the trends of beta and gamma band activities are almost similar in each percent of 30% and 70% MVC. Right brain hemisphere shows more activity than left hemisphere in beta and gamma rhythm after fatigue state at 70% MVC. Copyright © Journal of Biomedical Physics and Engineering.Background Ionizing radiation is present in all environment of the Earth's surface, beneath the Earth and in the atmosphere. Human beings are exposed to external radiation from their surroundings naturally and also to internal radiation from food, water and air they consume. Then, it is important to measure and develop knowledge about radiation. Objective This study is designed to evaluate the risks of radiation outdoors and indoors and in hot spring in Gachine area of Bandar Abbas. Materials and Methods The device used in this cross sectional study was environmental radiation surveymeter. Indoor gamma radiation in Gachine area was carried out inside 115 dwellings. Measurement for hot spring waters was carried out at one meter above water level. Dose rates were recorded for an hour. Results Our results indicate the outdoor dose rate gamma radiation in Gachine area is higher than the global mean dose rate. Moreover, Gachine Bala has the highest outdoor gamma radiation (78.87 nGy/h) and Gachine Paien has the lowest gamma background radiation (71.62 nGy/h). Conclusion This study demonstrates that indoor mean dose rate of gamma radiation in this area is higher than the global mean dose rate. Estimated indoor mean dose rates were for Gachine Paien (110.58 nGy/h), Gachine Bala (111.83 nGy/h), Ship industry dwelling (109.30 nGy/h) and Jamal Ahmad (107.84 nGy/h). The highest dose rate above hot spring was obtained from Chostaneh (1320 nGy/h). Copyright © Journal of Biomedical Physics and Engineering.Background Male infertility is defined as an inability to impregnate a fertile female; it is a widespread problem which is usually caused by some male factors such as low quantity and quality of sperm, specifically oligospermia and azoospermia. Objective This study aimed to evaluate the bio-positive effects of low power density Wi-Fi radiation on the reproductive system of infertile and healthy mice. Materials and Methods In this experimental study, thirty adult male Balb/c mice were randomly divided into 5 groups. Groups oligospermic-sham (OS), oligospermic-exposure 1 (OE1) and oligospermic-exposure 2 (OE2) received Busulfan, 10 mg/kg, intraperitoneally, but the control-sham (CS) and control-exposure (CE) groups left without Busulfan therapy. Groups CE, OE1 and OE2 were exposed to 2.4 GHz Wi-Fi radiation while, the CS and OS were sham exposed to Wi-Fi radiation without energizing the Wi-Fi router. The right and left testes and right epididymis were dissected out and histopathological, histomorphologic changes and the quality of the sperms were analyzed. Results Low power density Wi-Fi radiation significantly increased sperm concentration in the CE group compared to that in CS, while enhancement of spermatid cells was not significant. Sperm concentration in OE2 was more than that in OE1 as the spermatid cells enhanced. Conclusion Findings revealed that radiation hormesis induced by low power density Wi-Fi radiation have biological beneficial effects on mouse sperm concentration and sperm histomorphometric parameters. Copyright © Journal of Biomedical Physics and Engineering.