• Journal of Biomedical Engineering Research
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• v.15 no.3
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• pp.265-274
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• 1994

This paper proposes a method of noninvasive reflectance light to measure the blood fractional volume (Vb) and oxygen saturation ($SO_2$) of biological tissue. We chose the red light of 660nm and infrared light of 880nm. In Vivo reflectance data were obtained by the physiological changes front the surface of the skin over the calf in human subject. The reflected light intensity from different layers within a biological tissue was measured by specially designed reflectometer to apply photon path diffusion model. The collected data represent the changes of blood (ractional volume and oxygen saturation at each reflected light wavelengths. The data evaluation was assessed by examining the slopes of the plotted indices for the changes in oxygen saturation and blood (ractional volume. The results presented in this paper claim that light reflectance can separately discriminate the change of blood volume and that of oxygenation in muscle and also in skin.

• Journal of Biomedical Engineering Research
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• v.19 no.6
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• pp.603-609
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• 1998

To anlyze the diffuse axonal injury of the human brain, 3-D finite element models of the adult, two and three years child were developed. Triangular type acceleration which had its maximum value 200g was applied to investigate the effects of acceleration direction and duration time. The pattern of high shear stress generated at the brain stem, pones and midbrain was similar to the pattern of DAI seen in the clinical observation, especially high maximum shear stress was detected in the brain stem of the six year old child model under flexional acceleration. As the duration of acceleration increased generated pressure and maximum shear stress also increased. For the children's model relatively small pressure was generated regardless of the acceleration direction and continued much longer compared with adult's model. From this analysis maximum shear stress was revealed more proper indicator to predict DAI compared to HIC in case of angular acceleration loading.

• Progress in Medical Physics
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• v.21 no.1
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• pp.35-41
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• 2010

The purpose of this study is to quantitate regional neurochemical profile of regional normal adult mice brain and assess regional metabolic differences by using ex vivo $^1H$ high-resolution magic angle spinning nuclear magnetic resonance spectroscopy ($^1H$ HR-MAS NMRS). The animals were matched in sex and age. The collected brain tissue included frontal cortex, temporal cortex, thalamus, and hippocampus. Quantitative 1D spectra were acquired on 40 samples with the CPMG pulse sequence (8 kHz spectral window, TR/TE = 5500/2.2 ms, NEX = 128, scan time: 17 min 20 sec). The mass of brain tissue and $D_2O$+TSP solvent were 8~14 mg and 7~13 mg. A total of 16 metabolites were quantified as follow: Acet, NAA, NAAG, tCr, Cr, tCho, Cho, GPC + PC, mIns, Lac, GABA, Glu, Gln, Tau and Ala. As a results, Acet, Cho, NAA, NAAG and mIns were showed significantly different aspects on frontal cortex, hippocampus, temporal cortex and thalamus respectively. The present study demonstrated that absolute metabolite concentrations were significantly different among four brain regions of adult mice. Our finding might be helpful to investigate brain metabolism of neuro-disease in animal model.

• 한국생물공학회:학술대회논문집
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• 2003.04a
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• pp.98-100
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• 2003

Synthetic polymers such as PET and ePTFE have widely been used for artificial vascular patches. However, these materials cannot function for a long term as blood vessel due to thrombotic occlusion and calcification. To overcome this limitation, a biocompatible vascular patch was developed using stem cell and tissue engineering approach. Autologous bone marrow mesenchymal stem cells were differentiated into vascular endothelial cells and smooth muscle cells. These cells were seeded onto collagen patch matrices. The matrices were anastomosed to abdominal arteries in canine models. Prior to implantation, histological and scanning electron microscopical examination revealed stem cell adhesion and growth on the matrices. At 3 weeks, the implanted vascular patches were patent. Histological examination showed the regeneration of endothelium, media and adventitia in the grafts. Cell tracing analysis using fluorescent reagent showed that labeled stem cells were present in the implanted grafts and contributed to the regeneration of vascular tissues. This study may help us develop a tissue-engineered vascular patch appropriate for clinical applications.

• Journal of IKEEE
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• v.23 no.4
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• pp.1122-1127
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• 2019

In this study, the bio-impedance of the human body is able to obtain a lot of information by monitoring the pathological and physiological conditions of clinical and biological tissues. The four electrode method system for biometrics measured the potential difference between two electrodes and the other two electrodes were used as electrodes for current flow. The newly developed dry gold electrode measured impedance from 1 Hz to 50 kHz and produced reproducible results. To verify the impedance measurement of the dry electrode, the pitting was performed using an equivalent circuit model of the bioelectrode skin, and the effectiveness was demonstrated through modeling. Fixed electrode types have a constant position of the electrodes attached during the measurement, so that a stable measurement can be obtained, thereby minimizing the error.

• Journal of the Korea Convergence Society
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• v.9 no.3
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• pp.257-263
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• 2018

Hyperthermia supplies RF high-frequency energy above 1MHz to the tumor tissue through the electrodes. And the temperature of the tumor tissue is increased to $42^{\circ}C$ or more to cause thermal necrosis. A mathematical model can be derived a human body model for absorption and transmission of electromagnetic energy in the human model and It is possible to evaluate the distribution of temperature fields in biological tissues. In this paper, we build the human model based on the adult standard model of the geometric shape of the 3D model and use the FVM code. It is assumed that Joule heat is supplied to the anatomical model to simulate the magnetic field induced by the external electrode and the temperature distribution was analyzed for 0-1,200 seconds. As a result of the simulation, it was confirmed that the transferred energy progressively penetrates from the edge of the electrode to the pulmonary tumors and from the skin surface to the subcutaneous layer.

• Journal of Veterinary Clinics
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• v.32 no.5
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• pp.404-409
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• 2015

The objective of this study was to compare the biocompatibility for local irritation and bioavailability of $Gentacol^{TM}$ and $Collatamp^{TM}$, after single intramuscular loading in rats. Sixty-six male Sprague-Dawley rats were divided into 4 groups; (1) any test materials were not applied into the quadriceps muscles (control group, N = 6), (2) Gentamicin was injected into the quadriceps muscles (Gentamicin group, N = 6), (3) Collatamp was applied into the quadriceps muscles (Collatamp group, N = 27), and (4) Gentacol was applied into the quadriceps muscles (Gentacol group, N = 27). The concentration of gentamicin in muscles was gradually decreased with time after loaded in the both $Gentacol^{TM}$ and $Collatamp^{TM}$ loaded regions. No detectable gentamicin was observed in the plasma of $Gentacol^{TM}$ and $Collatamp^{TM}$ loaded rats. Histologically, moderate to severe inflammatory cell infiltrations including PMN, lymphoid cells and macrophages were observed with slight to moderate edematous changes of muscle fibers after intramuscular injection of gentamicin. However, these histopathological changes of gentamicin injection induced local irritations were dramatically decreases after intramuscular loading of $Collatamp^{TM}$ and $Gentacol^{TM}$. These results suggest $Gentacol^{TM}$ may show favorable local bioavailability and induce only slight local irritations as comparable as $Collatamp^{TM}$ without systemic exposures in the condition of this experiment.

• Reproductive and Developmental Biology
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• v.32 no.1
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• pp.1-7
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• 2008

The SCID-repopulation cells(SRCs) assay has been widely used to determine the self-renewal capacity of hematopoietic stem cells (HSCs). In this study, we tested the repopulating efficiency of porcine bone marrow derived hematopoietic stem cells using nonobese diabetic/severe combined immunodieficient (NOD/SCID) mice which was inherited immunodeficiency mire with defect of T cells, B cells, and low activity of NK cells. We transplanted porcine bone marrow hematopoietic stem/progenitor cells with intraperitoneal injection into neonate NOD/SCID mice. We confirmed efficient reconstitution activity of inoculated porcine hematopoietis cells in variety of organs of NOD/SCID mice. Interestingly, pig $CD3^+$ T lymphocytes detected with high level in liver($15.6{\pm}3.7%$), spleen($5.6{\pm}3.0%$), thymus($1.5{\pm}1.3%$), and BM($2.3{\pm}0.9%$), respectively. These data imply that microenvironment of neonate NOD/SCID mice is very efficient for proliferation and differentiation of porcine T cells, and can be useful for the study of T cells development and renogeneic organ transplantation.

• Journal of the Korean Society of Radiology
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• v.10 no.2
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• pp.139-144
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• 2016

The study of radiation-hazard in the human skin tissue is carried out by direct irradiating to experimental animals. The influences of a radiation to the animal's skin tissue are analyzed from this experiment. However, this also accompanies losses in terms of both time and economy. In this study, we simulated human tissue by using a swine skin tissue. The depth of the swine skin tissue for the experiment is determined, and the amount of the direct radiation below this skin depth is analyzed numerically. The amount of the radiation occurred by exposure below the skin tissue can be inferred. Moreover, it is possible to use only cells effectively and animal experiments to analyze the body-hazard by radiation.

• Proceedings of the Korea Society of Poultry Science Conference
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• 2006.11a
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• pp.80-81
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• 2006

닭의 유전자 지도가 밝혀지고 그와 관련한 생물학적 연구들이 활발히 이루어지면서 닭을 생체 반응기나 질병 모델 동물로 이용하기 위한 연구가 많이 진행되고 있다. 이 중 닭을 생체 반응기로 이용하기 위해서는 많은 양의 단백질을 생산하는 난관에 대한 연구가 필수적이다. In vivo와 in vitro에서 난관 특이적 프로모터에 의한 외래 유전자의 발현에 대한 연구를 하였고 유전자를 전이하는 방법으로는 렌티 바이러스 시스템을 이용하였으며, 프로모터는 난관 특이적 프로모터인 오브알부민 프로모터 (5‘ 조절 부분의 1.4kb)와 RSV 프로모터를 이용하였다. 리포터 유전자로는 형광발현 단백질 (enhanced green fluorescence protein, EGFP)을 이용해서 마우스 배아 섬유아세포, 닭 배아 섬유아세포, 난관 상피 세포에서 발현을 유도해서 조직 특이적 발현 여부를 확인하였다. 그 결과 RSV 프로모터는 모든 세포에서 발현하였으나, 오브알부민 프로모터에 의한 리포터 유전자의 발현은 난관 상피 세포에서는 특이적으로 발현하였다. 이와 같은 연구는 산란계를 이용해서 난관으로부터 효율적인 생리 활성 물질을 생산하기 위한 가능성을 보여주었다.