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A numerical investigation into the magnetic nanoparticles hyperthermia cancer treatment injection strategies

Dahaghin Ali, Emadiyanrazavi Seyedhamidreza, Salimibani Milad, Bahreinizad Hossein, Haghpanahi Mohammad, Eivazzadeh-Keihan Reza, Maleki Ali

Biocybernetics and Biomedical Engineering

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2021

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Vol. 41, no. 2

516--526

EN

Magnetic nanoparticles hyperthermia is a new and promising cancer treatment method. Injection strategies are one of the determining factors in the success of the treatment. This study is a numerical investigation into the injection methods of MNPs hyperthermia. In order to have a realistic tumor morphology and vascularity, a model of Lower Limb tumor was constructed from the CT images. The finite element method was used to solve the problem. This study includes fluid flow in capillaries and inside the porous tissue of the tumor, mass transfer from the capillaries into the tumor tissue, inside the tumor tissue, and from the tumor tissue into the capillaries, and finally heat transfer across the tumor. Finally, tissue damage was calculated in order to evaluate the performance of each method. Results of intravenous injection with single point intratumoral injections were compared here. The results of this study show that intravenous injection yields more homogenous MNPs concentration and temperature distribution, while MNPs concentration and temperature increase in direct injection was limited in a small area around the injection point. Results of the current research suggest that damage to tissue from the hyperthermia with intravenous injection is much more significant compared to direct injection.

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Muscle coordination analysis by time-varying muscle synergy extraction during cycling across various mechanical conditions

Esmaeili Javad, Maleki Ali

Biocybernetics and Biomedical Engineering

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2020

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Vol. 40, no. 1

90--99

EN

Central nervous system (CNS) uses the combination of a small number of motor primitives, named muscle synergies, for simplification of motor control in human movement. The aim of this study was to investigate the muscle coordination in both leg muscles during pedaling by time-varying muscle synergy extraction. Twenty healthy subjects performed three 6-min cycling tasks over a range of rotational speed (40, 50, and 60 rpm) and resistant torque (3, 5, and 7 N/M). Surface electromyography signals were recorded during pedaling from eight muscles of the right and left lower limbs. We extracted four time-varying muscle synergies from sEMG patterns. Mean and standard deviation of the quality of the signal reconstruction (R2) for all subjects was obtained 0.9328 ± 0.0120. We investigated the similarity of muscle synergies during cycling across various mechanical conditions. We found the high degrees of similarity (>0.85) among the sets of time-varying muscle synergies across mechanical conditions and also across subjects. Our results show that the same motor control strategies for cycling are used by all subjects in various mechanical conditions.

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Fractal Analysis of Noise Signals of Sampo and John Deere Combine Harvesters in Operational Conditions

Boroujeni Farzad Mahdiyeh, Maleki Ali

Archives of Acoustics

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2019

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Vol. 44, No. 1

89--98

EN

Combine harvesters are the source a large amount of noise in agriculture. Depending on different working conditions, the noise of such machines can have a significant effect on the hearing conditio of drivers. Therefore, it is highly important to study the noise signals caused by these machines and find solutions for reducing the produced noise. The present study was carried out is order to obtain the fractal dimension (FD) of the noise signals in Sampo and John Deere combine harvesters in different operational conditions. The noise signals of the combines were recorded with different engine speeds, operational conditions, gear states, and locations. Four methods of direct estimations of the FD of the waveform in the time domain with three sliding windows with lengths of 50, 100, and 200 ms were employed. The results showed that the Fractal Dimension/Sound Pressure Level [dB] in John Deere and Sampo combines varied in the ranges of 1.44/96.8 to 1.57/103.2 and 1.23/92.3 to 1.51/104.1, respectively. The cabins of Sampo and John Deere combines reduced and enhanced these amounts, respectively. With an increase in the length of the sliding windows and the engine speed of the combines, the amount of FD increased. In other words, the size of the suitable window depends on the extraction method of calculating the FD. The results also showed that the type of the gearbox used in the combines could have a tangible effect on the trend of changes in the FD.