• Title/Summary/Keyword: Impedance tomography

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Review on the Research Related to Bangpungtongseong-san(Bofutsusho-san) in Korea (방풍통성산 관련 연구 분석)

  • Park, Jung-Hyun;Lee, Myeong-Jong;Kim, Ho-Jun
    • Journal of Korean Medicine Rehabilitation
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    • v.21 no.2
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    • pp.189-202
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    • 2011
  • Objectives : The objective of the review was to research related to Bangpungtongseong-san(Bofutsusho-san) in oriental medicine in South Korea. Methods : Oriental medicine advanced searching integrated system(OASIS), 4 Korean medical databases and 5 Korean medical journals were searched by using search terms as Bangpungtongseong-san or Bofutsusho-san. In order to see detail review, we classified all the searched studies into types, methods, purposes, outcome measures and main conclusions. Results : We found out total thirty one studies. There were seventeen experimental studies, four clinical studies, seven case reports and three literature reviews. The main thesis were related to metabolic syndrome, including obesity, hyperlipidemia and hypertension, etc. The studies about the safety and toxicity concluded Bangpungtongseong-san did not seem to affect toxicity. In the outcome measure, body mass index, serum biochemical analysis, cell study, abdominal computed tomography(CT) and bioelectrical impedance analysis were used. Conclusions : To improve more objective and continuous research in oriental medicine, further rigorous clinical trials using herbal medicines should be performed.

Effects of Far-infrared Therapy on Weight Loss in Korean Obese Women (전신 경피 원적외선 요법이 비만여성의 체중감소에 미치는 영향에 대한 임상연구)

  • Song, Eun-Mo;Kim, Eun-Joo;Kim, Koh-Woon;Cho, Jae-Heung;Song, Mi-Yeon
    • Journal of Korean Medicine for Obesity Research
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    • v.12 no.1
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    • pp.20-32
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    • 2012
  • Object The purpose of this study is to evaluate the effect of far-infrared (FIR) therapy on weight loss. Method Thirty five participants (BMI ${\geq}25kg/m^2$) were recruited. Body weight, Waist circumference (WC), Bio Impedance Analysis (BIA), abdominal fat Computer Tomography (CT) scanning were evaluated. Results of 25 women were analyzed. Result After 6 weeks of FIR therapy, there was significant efficacy on obese women in body weight, WC, Body fat mass (BFM), and Visceral fat area (VFA). But there was no efficacy in Total fat area (TFA), and Subcutaneous fat area (SFA). Conclusion This study suggests that FIR therapy might be an effective way to promote weight and abdominal visceral fat loss in Korean obese women.

Identification of Subsurface Discontinuities via Analyses of Borehole Synthetic Seismograms (시추공 합성탄성파 기록을 통한 지하 불연속 경계면의 파악)

  • Kim, Ji-Soo;Lee, Jae-Young;Seo, Yong-Seok;Ju, Hyeon-Tae
    • The Journal of Engineering Geology
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    • v.23 no.4
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    • pp.457-465
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    • 2013
  • We integrated and correlated datasets from surface and subsurface geophysics, drilling cores, and engineering geology to identify geological interfaces and characterize the joints and fracture zones within the rock mass. The regional geometry of a geologically weak zone was investigated via a fence projection of electrical resistivity data and a borehole image-processing system. Subsurface discontinuities and intensive fracture zones within the rock mass are delineated by cross-hole seismic tomography and analyses of dip directions in rose diagrams. The dynamic elastic modulus is studied in terms of the P-wave velocity and Poisson's ratio. Subsurface discontinuities, which are conventionally identified using the N value and from core samples, can now be identified from anomalous reflection coefficients (i.e., acoustic impedance contrast) calculated using a pair of well logs, comprising seismic velocity from suspension-PS logging and density from logging. Intensive fracture zones identified in the synthetic seismogram are matched to core loss zones in the drilling core data and to a high concentration of joints in the borehole imaging system. The upper boundaries of fracture zones are correlated to strongly negative amplitude in the synthetic trace, which is constructed by convolution of the optimal Ricker wavelet with a reflection coefficient. The standard deviations of dynamic elastic moduli are higher for fracture zones than for acompact rock mass, due to the wide range of velocities resulting from the large numbers of joints and fractures within the zone.

A STUDY ON THE SAFETY ANALYSIS OF ROCK FILL DAM (1) (필댐의 안정성 해석 연구 (1))

  • HoWoongShon;DaeKeunLee
    • Journal of the Korean Geophysical Society
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    • v.6 no.3
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    • pp.165-177
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    • 2003
  • The purpose of this paper is to analyze the behavior and to study the safety evaluation of the Unmun Dam located in Cheongdo-Gun of GyeongBuk Province, Korea. For this purpose, soil analyses including boring data, geophysical surveys were conducted. In this paper, especially many geophysical methods were adopted to configure out the subsurface situation of dam. Applied geophysical methods were: 1) electric resistivity survey, 2) high frequency magnetotelluric (HFMT) survey, 3) ground penetrating radar (GPR) survey, 4) seismic refraction survey, 5) seismic cross-hole tomography survey, and 6) high frequency impedance (ZHF) survey. Each of geophysical surveys were analyzed and joint analyses between geophysical surveys were also performed to deduce the more reliable subsurface information of Dam by using the features and characteristics of each geophysical survey. Since many defects, such as gravel and weathered rock blocks in the dam core, and lots of amounts of leakage, by boring analyses were found, reinforcement by compaction grouting system (CGS) has been conducted in some range of dam. Some geophysical data and data of geotechnical gauges were also used to confirm the effects of reinforcement. Electric resistivity, EM, GPR, ZHF, seismic refraction and seismic tomography surveys show that left side of dam is weak, which means the possibility of existence of gravel, rock block, water and cavities in the core of dam. This result coincides with the boring data. Especially, electric survey after reinforcement shows that even the right side of the dam has been deformed by the strong pressure during the reinforcement itself. As a conclusion, some problems in the dam found. Especially, the dam near spillway shows the high possibility of leakage. It should be pointed out that only the left side of he dam has not a leakage problem. As a whole, the dam has problems of weakness, because of unsatisfactory construction. It is strongly recommended that highly intensive monitoring is required.

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Usefulness of Abdominal Fat Measured by Computed Tomography and Bioelectric Impedance Analysis as an Obesity Index (컴퓨터단층촬영과 생체전기 저항 분석법으로 측정된 복부지방의 비만지표로서의 유용성)

  • Kim, Mi-Young;Kim, Hwa-Sun
    • The Journal of the Korea Contents Association
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    • v.11 no.12
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    • pp.807-813
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    • 2011
  • For obesity management requires accurate measurement of abdominal fat. The purpose of this study was to find out the correlation between abdominal fat and lipid measured with BIA and CT. Secondly, This study investigate for usefulness of abdominal fat measured by BIA and CT as an obesity index. As a result, TG showed higher value in the overweight obese group than normal group but HDL showed lower value in the overweight obese group than normal group. TG and HDL appeared significantly relationship with by BIA and CT in the normal group. However, in the overweight obese group TG showed significantly relationship with the BIA. According to multiple regression analysis on BMF and TAF was affected by HDL in the normal group. And BMF, %BF was affected by TG in overweight obese group. In conclusion, abdominal fat showed significant correlation with lipid. Abdominal fat measured by BIA and CT to assess obesity index is considered as a useful way to evaluate.

Conductivity Imaging of a Canine Head using a 3T MREIT System with a Carbon-Hydrogel Electrode: Postmortem Experiment (3T MREIT 시스템을 이용한 실험견 사체의 두부 도전율 영상)

  • Jeong, Woo-Chul;Kim, Young-Tae;Minhas, Atul S.;Kim, Hyung-Joong;Lee, Tae-Hwi;Kang, Byeong-Teck;Park, Hee-Myung;Woo, Eung-Je
    • Journal of Biomedical Engineering Research
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    • v.30 no.2
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    • pp.179-184
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    • 2009
  • Magnetic Resonance Electrical Impedance Tomography (MREIT) is a new bio-imaging modality providing cross-sectional conductivity images from measurements of internal magnetic flux densities produced by externally injected currents. Recent MREIT studies demonstrated successful conductivity image reconstructions of postmortem and in vivo canine brain. However, the whole head imaging was not achieved due to technical issues related with electrodes and noise in measured magnetic flux density data. In this study, we used a new carbon-hydrogel electrode with a large contact area and injected 30 mA imaging current through a canine head. Using a 3T MREIT system, we performed a postmortem canine experiment and produced high-resolution conductivity images of the entire canine head. Collecting magnetic flux density data inside the head subject to multiple injection currents, we reconstructed cross-sectional conductivity images using the harmonic $B_z$ algorithm. The conductivity images of the canine head show a good contrast not only inside the brain region including white and gray matter but also outside the brain region including the skull, temporalis muscle, mandible, lingualis proprius muscle, and masseter muscle.

Analysis of Eddy Current Effect in Magnetic Resonance Imaging Using the Finite Element Method (유한요소법에 의한 자기공명영상시스템에서의 와전류 영향 분석)

  • Lee, Jeong-Han;Gang, Hyeon-Su;Jo, Min-Hyeong;Mun, Chi-Ung;Lee, Gang-Seok;Lee, Su-Yeol
    • Journal of Biomedical Engineering Research
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    • v.20 no.1
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    • pp.53-58
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    • 1999
  • Eddy current in MRI systems degrades gradient field linearity and distorts gradient waveform. When the waveform distortion is spatially variant, it is very difficult to perform special imaging techniques such as the echo planar imaging technique or the fast spin echo imaging technique. In this study, we have developed a new technique to estimate the distorted gradient waveforms at any points inside the imaging region using the finite element method. After obtaining the eddy-current-effect transfer function, which represents magnitude and phase characteristics of the gradient field at a particular point, we have used the transfer function to estimate the actual gradient waveforms at the point. To verify the proposed technique, we have compared the estimated gradient waveforms with the measured ones.

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Improved Current Source Design to Measure Induced Magnetic Flux Density Distributions in MREIT

  • Oh Tong-In;Cho Young;Hwang Yeon-Kyung;Oh Suk-Hoon;Woo Eung-Je;Lee Soo-Yeol
    • Journal of Biomedical Engineering Research
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    • v.27 no.1
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    • pp.30-37
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    • 2006
  • Injecting currents into an electrically conducting subject, we may measure the induced magnetic flux density distributions using an MRI scanner. The measured data are utilized to reconstruct cross-sectional images of internal conductivity and current density distributions in Magnetic Resonance Electrical Impedance Tomography (MREIT). Injection currents are usually provided in a form of mono-polar or bi-polar pulses synchronized with an MR pulse sequence. Given an MRI scanner performing the MR phase imaging to extract the induced magnetic flux density data, the current source becomes one of the key parts determining the signal-to-noise ratio (SNR) of the measured data. Since this SNR is crucial in determining the quality of reconstructed MREIT images, special care must be given in the design and implementation of the current source. This paper describes a current source design for MREIT with features including interleaved current injection, arbitrary current waveform, electrode switching to discharge any stored charge from previous current injections, optical isolation from an MR spectrometer and PC, precise current injection timing control synchronized with any MR pulse sequence, and versatile PC control program. The performance of the current source was verified using a 3T MRI scanner and saline phantoms.

Application of Borehole Radar to Tunnel Detection (시추공 레이다 탐사에 의한 지하 터널 탐지 적용성 연구)

  • Cho, Seong-Jun;Kim, Jung-Ho;Kim, Chang-Ryol;Son, Jeong-Sul;Sung, Nak-Hun
    • Geophysics and Geophysical Exploration
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    • v.9 no.4
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    • pp.279-290
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    • 2006
  • The borehole radar methods used to tunnel detection are mainly classified into borehole radar reflection, directional antenna, crosshole scanning, and radar tomography methods. In this study, we have investigated the feasibility and limitation of each method to tunnel detection through case studies. In the borehole radar reflection data, there were much more clear diffraction signals of the upper wings than lower wings of the hyperbolas reflected from the tunnel, and their upper and lower wings were spreaded out to more than 10m higher and lower traces from the peaks of the hyperbolas. As the ratio of borehole diameter to antenna length increases, the ringing gets stronger on the data due to the increase in the impedance mismatching between antennas and water in the boreholes. It is also found that the reflection signals from the tunnel could be enhanced using the optimal offset distance between transmitter and receiver antennas. Nevertheless, the borehole radar reflection data could not provide directional information of the reflectors in the subsurface. Direction finding antenna system had a advantage to take a three dimensional location of a tunnel with only one borehole survey even though the cost is still very high and it required very high expertise. The data from crosshole scanning could be a good indicator for tunnel detection and it could give more reliable result when the borehole radar reflection survey is carried out together. The images of the subsurface also can be reconstructed using travel time tomography which could provide the physical property of the medium and would be effective for imaging the underground structure such as tunnels. Based on the results described above, we suggest a cost-effective field procedure for detection of a tunnel using borehole radar techniques; borehole radar reflection survey using dipole antenna can firstly be applied to pick up anomalous regions within the borehole, and crosshole scanning or reflection survey using directional antenna can then be applied only to the anomalous regions to detect the tunnel.

Numerical Analysis of Three-Dimensional Magnetic Resonance Current Density Imaging (MRCDI) (3차원 자기공명 전류밀도 영상법의 수치적 해석)

  • B.I. Lee;S.H. Oh;E.J. Woo;G. Khang;S.Y. Lee;M.H. Cho;O. Kwon;J.R. Yoon;J.K. Seo
    • Journal of Biomedical Engineering Research
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    • v.23 no.4
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    • pp.269-279
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    • 2002
  • When we inject a current into an electrically conducting subject such as a human body, voltage and current density distributions are formed inside the subject. The current density within the subject and injection current in the lead wires generate a magnetic field. This magnetic flux density within the subject distorts phase of spin-echo magnetic resonance images. In Magnetic Resonance Current Density Imaging (MRCDI) technique, we obtain internal magnetic flux density images and produce current density images from $\bigtriangledown{\times}B/\mu_\theta$. This internal information is used in Magnetic Resonance Electrical Impedance Tomography (MREIT) where we try to reconstruct a cross-sectional resistivity image of a subject. This paper describes numerical techniques of computing voltage. current density, and magnetic flux density within a subject due to an injection current. We use the Finite Element Method (FEM) and Biot-Savart law to calculate these variables from three-dimensional models with different internal resistivity distributions. The numerical analysis techniques described in this paper are used in the design of MRCDI experiments and also image reconstruction a1gorithms for MREIT.