• 제목/요약/키워드: Biomedical field

검색결과 828건 처리시간 0.025초

The Effect of Magnetic Field Direction on the EEG and PPG Obtained from Pulsed Magnetic Stimulus at Acupoint PC9

  • Kim, Sun-Wook;Lee, Jin-Yong;Lee, Hyun-Sook
    • Journal of Magnetics
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    • 제16권3호
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    • pp.259-262
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    • 2011
  • Compared to acupuncture, the pulsed magnetic field (PMF) stimulus is a useful tool for treatment of many physical conditions and health maintenance due to its advantages as a noninvasive and nontoxic medical treatment. The purpose of this study was to investigate the effect of PMF stimulus direction at PC9 on the alpha activity of electroencephalogram (EEG) and vascular aging calculated from photoplethysmograph (PPG). It can be concluded that the direction of PMF stimulus affects the increase of alpha activity of EEG and PPG, indicating the vascular stiffness and the sclerosis level of blood vessels weakly relevant to the direction of PMF stimulus.

Study on Improvement of Blood Stagnation by Pulsed Magnetic Field

  • Son, Hee Jung;Yoo, Jun Sang;Lee, Myeung Hee;Hwang, Do Gwen;Lee, Hyun Sook
    • Journal of Magnetics
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    • 제20권2호
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    • pp.114-119
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    • 2015
  • This study explored the effect of pulsed magnetic field (PMF) stimulus on the improvement of blood stagnation by means of photoplethysmography (PPG). Our stimulus system was designed to generate PMF with a maximum intensity variation of 0.20 T at a transition time of $160{\mu}s$, with pulse intervals of 1 Hz. In order to quantitatively estimate vascular condition, indices such as blood vessel tension (BVT), stress power (SP), differential pulse wave index (DPI) and remained blood volume (RBV) were calculated from the second derivative of the PPG signal and power density spectrum (PDS). Our results showed that non-invasive PMF stimulus was effective in improving blood stagnation. Therefore, it may be concluded that appropriate PMF stimulus affects the blood circulatory system.

Electrical Properties of a CuPc Field-Effect Transistor Using a UV/Ozone Treated and Untreated Substrate

  • Lee, Ho-Shik;Cheon, Min-Woo;Park, Yong-Pil
    • Transactions on Electrical and Electronic Materials
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    • 제12권1호
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    • pp.40-42
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    • 2011
  • An organic field-effect transistor (OFET) was fabricated using a copper phthalocyanine (CuPc) as the active layer on the silicon substrate. The CuPc FET device was configured as a top-contact type. The substrate temperature was room temperature. The CuPc thickness was 40 nm, and the channel length and channel width were 100 ${\mu}m$ 3 mm, respectively. Typical current-voltage (I-V) characteristics of the CuPc FET were observed and subsequently compared to the UV/ozone treatment on substrate surface.

Assessment of Malignancy in Human Brain Tumors by in vivo 1H MR Spectroscopy at 3 Tesla

  • Choe, Bo-Young;Baik, Hyun-Man;Chu, Myung-Ja;Kwon, Kang-Sei;Chung, Sung-Taek;Oh, Chang-Hyun;Kim, Sun-I;Park, Chi-Bong;Lee, Hyoung-Koo
    • 대한자기공명의과학회:학술대회논문집
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    • 대한자기공명의과학회 2002년도 제7차 학술대회 초록집
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    • pp.80-80
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    • 2002
  • Purpose: Three tesla high field MR has been important to those disciplines that are SNR limited, such as MR spectroscopy. Additionally, increased spectral dispersion is critical for minimizing spectral overlap and simplifying resonance structures. The purpose of this study was to assess clinical proton MR spectroscopy (MRS) as a noninvasive method for evaluating brain tumor malignancy at 3T high field system Materials and Methods: Using 3T MRI/MRS system, localized water-suppressed single-voxel technique in patients with brain tumors was employed to evaluate spectra with peaks of N-acetyl aspartate (NAA), choline-containing compounds (Cho), creatine/phosphocreatine (Cr) and lactate. On the basis of Cr, these peak areas were quantificated as a relative ratio.

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Detection of Neuronal Activity by Motion Encoding Gradients: A Snail Ganglia Study

  • Park, Tae-S.;Park, Ji-Ho;Cho, Min-H.;Lee, Soo-Y.
    • 대한의용생체공학회:의공학회지
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    • 제28권1호
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    • pp.24-28
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    • 2007
  • Presuming that firing neurons have motions inside the MRI magnet due to the interaction between the neuronal magnetic field and the main magnetic field, we applied motion encoding gradients to dissected snail ganglia to observe faster responding MRI signal than the BOLD signal. To activate the snail ganglia in synchronization with the MRI pulse sequence, we used electrical stimulation with the frequency of 30 Hz and the pulse width of 2s. To observe the fast responding signal, we used the volume selected MRI sequence. The magnetic resonance signal intensity, measured with 8 ms long motion encoding gradient with a 20mT/m gradient strength, decreased about $3.46{\pm}1.48%$ when the ganglia were activated by the electrical stimulation.

고주파 자기장을 이용한 온침 치료시스템의 임상 평가 (Clinical Assessment of Warm Acupuncture Therapy System Using HF Time-varying Magnetic Field)

  • 이수용;변상준;최예빈;김진주;이용흠
    • Korean Journal of Acupuncture
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    • 제33권4호
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    • pp.213-220
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    • 2016
  • Objectives : The aim of this paper is to develop acupuncture needle heating system by utilizing the new method which uses high frequency(HF) time-varying magnetic field. Also, it is possible to make an assessment for reliability and clinical significance of the system. Methods : We designed the system with solenoid coils for generation of HF time-varying magnetic field that oscillates at 150 kHz. Acupuncture needles are quickly magnetized and heated by 150 kHz. We assessed clinical significance of system, such as body temperature, pressure pulse waveform. Results : Temperature of acupuncture needle increased up to 60 degree. In the result for clinical significance of system, in case of manual acupuncture stimulation(MAS), body temperature change was $0.373^{\circ}C{\pm}0.224$(p<0.05), rate of pulse energy change increased about 7.6%. In case of warm acupuncture stimulation(WAS), body temperature change was $0.645^{\circ}C{\pm}0.281$(p<0.05), rate of pulse energy change remarkably increased about 35.9%. Conclusions : We confirm that the system is able to be applied clinically to various warm acupuncture needle therapy in the area of oriental medicine.

각종 전기기기 및 장소에서의 전자파 측정 (Electromagnetic Forces Measurement of Various Electric Appliances and Places)

  • 김덕원;류창용;김수찬;윤형로
    • 대한의용생체공학회:학술대회논문집
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    • 대한의용생체공학회 1995년도 춘계학술대회
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    • pp.179-182
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    • 1995
  • Although air, water, and noise pollutions have been widely recognized, electromagnetic forces(EMF) hazard has been rarely recognized as a pollution and very little studies has been done in this country. Thus, in this study electromagnetic forces radiated by various home appliances, once machines, and communication equipments were measured and so were several places radiating strong EMF such as subway stations and electric substations. Among the home appliances microwave oven senates lots of magnetic field and microwaves, and electric mattress does strong magnetic field. In video game room strong magnetic and considerable electric fields were measured. It was observed strong magnetic field inside of electric powered train and very strong magnetic and electric fields on some platforms. Hand-phone and car-phone radiate very hazardous level of microwaves to brain and that they rapidly come into wide use. In this study data base for various electric machines and places radiating strong EMFs were constructed and could be used for future epidemiological studies.

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Exchange Bias Coupling Depending on Uniaxial Deposition Field of Antiferromagnetic FeMn Layer

  • Lee, Sang-Suk;Hwang, Do-Guwn
    • Journal of Magnetics
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    • 제15권1호
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    • pp.17-20
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    • 2010
  • The relationship between ferromagnet anisotropic magnetization and the antiferromagnet atomic spin configuration was investigated for various angles of the uniaxial deposition magnetic field of the FeMn layer in the Corning glass/Ta(5nm)/NiFe(7nm)/FeMn(25nm)/Ta(5nm) multilayer that was prepared by the ion beam sputter deposition. The exchange bias field ($H_{ex}$) obtained from the measurement of the easy-axis MR loop decreased to 40 Oe at the deposition field angle of $45^{\circ}$, and to 0 Oe at the angle of $90^{\circ}$. When the difference between the uniaxial axis between the ferromagnet NiFe and the antiferromagnet FeMn was $90^{\circ}$, the strong antiferromagnetic dipole moment of FeMn caused the weak ferromagnetic dipole moment of NiFe to rotate in the interface.

Apoptosis by Direct Current Treatment in Tumor Cells and Tumor Tissues

  • Kim, H. B.;S. B. Sim;S. Ahn
    • 한국생물물리학회:학술대회논문집
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    • 한국생물물리학회 2003년도 정기총회 및 학술발표회
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    • pp.48-48
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    • 2003
  • Electric field induces cell fusion, electroporation on biological cells, including apoptosis. Apoptosis is expressed in a series of natural enzymatic reactions for the natural elimination of unhealthy, genetically damaged, or otherwise aberrant cels that are not needed or not advantageous to the well-being of the organism. Its markers involve cell shringkage, activation of intracellular caspase proteases, externalization of phosphatidylserine at the plasma membrane, and fragmentation of DNA.

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