Analysis of Current Density and Specific Absorption Rate in Biological Tissue Surrounding Transcutaneous Transformer for an Artificial Heart

Suyama, Kenji; Nukaya, Masayuki; Tsuji, Toshio; Koshiji, Kohji

doi:10.1109/tbme.2007.900550

Cited by 38 publications

(18 citation statements)

References 23 publications

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“…According to the previous description, the Specific Absorption Rate (SAR) of the tissue is calculated in the following equation [52]: SAR = σ· E 2 /ρ, where σ is the conductivity of the tissue, ρ is the tissue mass, and E is the electric field intensity inside the tissue. The temperature alterations due to the energy absorption are able to be numerically quantified by analyzing the bioheat transfer equation based on the obtained SAR value [53].…”

Section: Discussionmentioning

confidence: 99%

Moderate-Intensity Rotating Magnetic Fields Do Not Affect Bone Quality and Bone Remodeling in Hindlimb Suspended Rats

Jing

Cai

et al. 2014

PLoS ONE

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Abundant evidence has substantiated the positive effects of pulsed electromagnetic fields (PEMF) and static magnetic fields (SMF) on inhibiting osteopenia and promoting fracture healing. However, the osteogenic potential of rotating magnetic fields (RMF), another common electromagnetic application modality, remains poorly characterized thus far, although numerous commercial RMF treatment devices have been available on the market. Herein the impacts of RMF on osteoporotic bone microarchitecture, bone strength and bone metabolism were systematically investigated in hindlimb-unloaded (HU) rats. Thirty two 3-month-old male Sprague-Dawley rats were randomly assigned to the Control (n = 10), HU (n = 10) and HU with RMF exposure (HU+RMF, n = 12) groups. Rats in the HU+RMF group were subjected to daily 2-hour exposure to moderate-intensity RMF (ranging from 0.60 T to 0.38 T) at 7 Hz for 4 weeks. HU caused significant decreases in body mass and soleus muscle mass of rats, which were not obviously altered by RMF. Three-point bending test showed that the mechanical properties of femurs in HU rats, including maximum load, stiffness, energy absorption and elastic modulus were not markedly affected by RMF. µCT analysis demonstrated that 4-week RMF did not significantly prevent HU-induced deterioration of femoral trabecular and cortical bone microarchitecture. Serum biochemical analysis showed that RMF did not significantly change HU-induced decrease in serum bone formation markers and increase in bone resorption markers. Bone histomorphometric analysis further confirmed that RMF showed no impacts on bone remodeling in HU rats, as evidenced by unchanged mineral apposition rate, bone formation rate, osteoblast numbers and osteoclast numbers in cancellous bone. Together, our findings reveal that RMF do not significantly affect bone microstructure, bone mechanical strength and bone remodeling in HU-induced disuse osteoporotic rats. Our study indicates potentially obvious waveform-dependent effects of electromagnetic fields-stimulated osteogenesis, suggesting that RMF, at least in the present form, might not be an optimal modality for inhibiting disuse osteopenia/osteoporosis.

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Section: Discussionmentioning

confidence: 99%

Moderate-Intensity Rotating Magnetic Fields Do Not Affect Bone Quality and Bone Remodeling in Hindlimb Suspended Rats

Jing

Cai

et al. 2014

PLoS ONE

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“…These currents can stimulate neural or muscle excitation or actions as it has been researched for MRI (Magnetic Resonant Images) [7]. Thus, the restriction of the induced current magnitude flowing through a surface of the biological tissue can minimize these non-desired effects.…”

Section: B Electromagnetic Effects On Biological Tissuesmentioning

confidence: 99%

A systematic sensitivity analysis of the performance of a transcutaneous energy transmitter for design purposes

Ferreira

Lebensztajn

2013

J. Microw. Optoelectron. Electromagn. Appl.

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“…Thus, the battery on the secondary side is larger than the secondary side coil. Current density and the issue of specific absorption rate (SAR) for the artificial heart system were discussed in [20], and the results demonstrate that SAR is less than 5 mW/Kg and lower than the limit under all transmission conditions. The WETS was implemented using an LLC resonant converter and class-E amplifier.…”

Section: Circuit Implementationmentioning

confidence: 99%

A Primary Side Control Method for Wireless Energy Transmission System

Chan

Chen

2012

IEEE Trans. Circuits Syst. I

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This paper presents a primary side control method for a low power wireless energy transmission system (WETS), with no physical wire connection required between the primary and secondary-side circuits. The primary side control method implemented in the WETS does not require extra space in the secondary side to regulate transmission energy. A charging protection was embedded within the secondary side to monitor the charging current and battery voltage, and to protect the battery against over-charging current or voltage. LLC resonant converter and class-E amplifier structures with zero-voltage switching were utilized to minimize transmission loss due to leakage inductance. In our experiments, the secondary side battery was fed a stable charging current in constant-current mode and low current in constant-voltage mode where the battery voltage reached approximately 4.1 V. The results show that the WETS achieved primary side control in all air-gap conditions. The overall efficiency of the WETS with LLC resonant converter was between 33.5% and 54.1%, and that of the class-E amplifier was between 30% and 66.2% when operating in the constant-current mode.

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Analysis of Current Density and Specific Absorption Rate in Biological Tissue Surrounding Transcutaneous Transformer for an Artificial Heart

Cited by 38 publications

References 23 publications

Moderate-Intensity Rotating Magnetic Fields Do Not Affect Bone Quality and Bone Remodeling in Hindlimb Suspended Rats

Moderate-Intensity Rotating Magnetic Fields Do Not Affect Bone Quality and Bone Remodeling in Hindlimb Suspended Rats

A systematic sensitivity analysis of the performance of a transcutaneous energy transmitter for design purposes

A Primary Side Control Method for Wireless Energy Transmission System

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