• Restorative Dentistry and Endodontics
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• v.31 no.5
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• pp.359-370
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• 2006

The objective of this study was to investigate the effect of excessive occlusal loading on stress distribution on four type of cervical lesion, using a three dimensional finite element analysis (3D FEA). The extracted maxillary second premolar was scanned serially with Micro-CT. The 3D images were processed by 3D-DOCTOR. ANSYS was used to mesh and analyze 3D FE model. Four different lesion configurations representative of the various types observed clinically for teeth were studied. A static point load of 500N was applied to the buccal and lingual cusp (Load A and B). The principal stresses in lesion apex, and vertical sectioned margin of cervical wall were analyzed. The results were as follows 1. The patterns of stress distribution were similar but the magnitude was different in four types of lesion 2. The peak stress was observed at mesial corner and also stresses concentrated at lesion apex. 3. The compressive stress under load A and the tensile stress under load B were dominant stress. 4. Under the load, lesion can be increased and harmful to tooth structure unless restored.

• Journal of Korean Medicine Rehabilitation
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• v.25 no.4
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• pp.1-20
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• 2015

Objectives This study was intended to clarify the anti-inflammation and anti-oxidation effects of gamikyejakjimo-tang herbal acupuncture (GKHA) for osteoarthritis. Methods Osteoarthritis was induced by injection of MIA into right knee joint cavities of rats. Rats were divided into a total of 4 groups (n=8). The 4 groups were normal group, control group, positive comparison group and expeimental group. Indomethacin and GKHA were medicated for a total of 4 weeks. After that, functions of liver and kidney by AST, ALT, creatinine, BUN, DPPH and ABTS free radical scavenging activity, ROS (reactive oxygen species) production, NO (Total Nitric oxide), IL-$1{\beta}$, IL-6, TNF-${\alpha}$ production, weight changes in the hind legs of MIA-induced osteoarthritis rat, serum PGE2, TIMP-1, MMP-2, MMP-9, LTB4, hs-CRP, and white blood cells, neutrophils, lymphocytes, monocytes were measured. The volume of cartilage was observed by micro CT arthrography. H&E and Safranin-O staining were used to examine the injury of synovial tissue. Results 1. In the hind leg weight bearing measurement, level of weight was increased. 2. AST, ALT, BUN, creatinine were decreased. 3. The production of total white blood cell was decreased, and the production of neutrophils, lymphocytes, monocytes were significantly decreased. 4. The production of NO, PGE2, TIMP-1, MMP-2, MMP-9, LTB4 were significantly decreased, and the production of hs-CRP was also decreased but with no significance. 5. The cartilage volume was significantly increased. 6. In H&E staining and Safranin-O staning, the cartilage cell appeared to be proliferated, and proteoglycans appeared to be increased. Conclusions Based on the results above, Gamikyejakjimo-tang Herbal Acupuncture has anti-oxidation and anti-inflammation effects, which leads to suppressing the underlying causes and the progression of osteoarthritis.

• Journal of the Korean Society of Food Science and Nutrition
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• v.43 no.1
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• pp.30-39
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• 2014

HanPoong Leading (HPL)-04 were prepared with different oriental medicines (balk of Kalopanax pictus balk, Chaenomelis Fructus, Angelica gigas root, Zingiber officinale, Raphanus sativus Linne and Saururus chinensis Baill.) to investigate the protective effects of HPL-04 on cartilage degradation in knee osteoarthritis (OA). Rat articular chondrocytes incubated with rhIL-$1{\alpha}$ markedly increased matrix metalloproteinase (MMP)-2 and 9 activities, decreased cell viability and reduced chondrogenic gene expression. 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, MMP-2 and 9 activities and real time RT-PCR indicated that HPL-04 counteracted these harmful effects in dose-dependent manner. In addition, for experimental OA in vivo, monosodium iodoacetate (MIA, 0.5 mg/50 ${\mu}L$) was injected into knee joints of rats and administered HPL-04 to rats for 4 consecutive weeks after MIA treatment. The experimental data showed that treatment with HPL-04 significantly prevented of MMP-2 and 9 activities in articular cartilage. Histopathological and micro-CT evaluations of the knee joints also revealed that HPL-04 effectively ameliorated MIA-induced degenerative OA. In conclusion, HPL-04 has potential applicability for the prevention and treatment of degenerative OA.

• Journal of the Optical Society of Korea
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• v.20 no.5
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• pp.607-613
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• 2016

The pleura is known as an end target organ of exposure to toxic environmental materials such as fine particulate matter and asbestos. Moreover, long-term exposure to hazardous materials can eventually lead to fatal lung disease such as diffuse pleural fibrosis or mesothelioma. Chest computed tomography (CT) and ultrasound are gold standard imaging modalities for detection of advanced pleural disease. However, a diagnostic tool for early detection of pleural reaction has not been developed yet due to difficulties in imaging ultra-fine structure of the pleura. Optical coherence tomography (OCT), which provides cross-sectional images of micro tissue structures at a resolution of 2-10 μm, can image the mesothelium with a thickness of ~100 μm and therefore enables investigation of the early pleural reaction. In this study, we induced the early pleural reaction according to a time sequence after pleurodesis using talc, which has been widely used in the clinical field. The pleural reaction in talc grouped according to the time sequence (1st, 2nd, 4th weeks) showed a significant thickening (average thickness: 45 ± 7.5 μm, 80 ± 10.7 μm, 90 ± 12.5 μm), while the pleural reaction in sham and normal groups showed pleural change from normal to minimal thickening (average thickness: 16 ± 5.5 μm, 17 ± 4.5 μm, 15 ± 6.5 μm, and 12 ± 7.5 μm, 13 ± 2.5 μm, 12 ± 3.5 μm). The measurement of pleural reaction by pathologic examinations was well-matched with the measurement by OCT images. This is the first study for measuring the thickness of pleural reactions using a biophotonic modality such as OCT. Our results showed that OCT can be useful for evaluating the early pleural reaction.

• Restorative Dentistry and Endodontics
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• v.33 no.4
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• pp.323-331
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• 2008

Flexibility and fracture properties determine the performance of NiTi rotary instruments. The purpose of this study was to evaluate how geometrical differences between three NiTi instruments affect the deformation and stress distributions under bending and torsional conditions using finite element analysis. Three NiTi files (ProFile .06 / #30, F3 of ProTaper and ProTaper Universal) were scanned using a Micro-CT. The obtained structural geometries were meshed with linear, eight-noded hexahedral elements. The mechanical behavior (deformation and von Mises equivalent stress) of the three endodontic instruments were analyzed under four bending and rotational conditions using ABAQUS finite element analysis software. The nonlinear mechanical behavior of the NiTi was taken into account. The U-shaped cross sectional geometry of ProFile showed the highest flexibility of the three file models. The ProTaper, which has a convex triangular cross-section, was the most stiff file model. For the same deflection, the ProTaper required more force to reach the same deflection as the other models, and needed more torque than other models for the same amount of rotation. The highest von Mises stress value was found at the groove area in the cross-section of the ProTaper Universal. Under torsion, all files showed highest stresses at their groove area. The ProFile showed highest von Mises stress value under the same torsional moment while the ProTaper Universal showed the highest value under same rotational angle.

• Restorative Dentistry and Endodontics
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• v.36 no.2
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• pp.98-107
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• 2011

Caries remains prevalent throughout modern society and is the main disease in the field of dentistry. Although studies of this disease have used diverse methodology, recently, X-ray microtomography has gained popularity as a non-destructive, 3-dimensional (3D) analytical technique, and has several advantages over the conventional methods. According to X-ray source, it is classified as monochromatic or polychromatic with the latter being more widely used due to the high cost of the monochromatic source despite some advantages. The determination of mineral density profiles based on changes in X-ray attenuation is the principle of this method and calibration and image processing procedures are needed for the better image and reproducible measurements. Using this tool, 3D reconstruction is also possible and it enables to visualize the internal structures of dental caries. With the advances in the computer technology, more diverse applications are being studied, such automated caries assessment algorithms.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2019.10a
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• pp.5-5
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• 2019

DMZ는 살아있는 생물다양성의 보고로 지난 60여년동안 자연적으로 재생이 일어나고 환경적인 강제 보존 영향으로 높은 생태학적인 가치가 유지되고 있으며, 최근에는 남북교류에 대한 활발한 의지로 DMZ생태자원의 남북공동활용 방안에 대한 이슈가 급부상하고 있다. 이에 본 연구진은 3년전부터 DMZ에서 자생하는 식물에 대한 조사를 진행하여 총 200여종 이상의 자생식물의 표본과 추출물들을 보유하고 있으며, 이 추출물들을 활용 in vitro 와 in vivo 평가를 통해 비임상 평가에서 유효한 효과를 나타내는 후보물질들을 다수 찾아낼 수 있었다. 그 중 조팝나무(Spiraea prunifolia var. simpliciflora)는 쌍떡잎식물 장미과에 속하는 낙엽활엽관목으로 동북아시아 지역에 널리 분포되며 우리나라에서는 중부지방에 주로 서식한다고 알려져 있다. 예로부터 해열 및 소염, 신경통완화 치료등에 이용해왔다고 알려져 있으며 그 속에는 다양한 terpenoids, flavonoid 및 phenolic 화합물이 다량 함유되어 있다고 알려져 있다. 본 연구에서는 조팝나무 추출물을 이용하여 전구지방세포에서의 지방세포분화 억제 및 관련 유전자들의 활성을 확인한 후 고지방식이로 유도된 high-fat diet mouse model을 이용하여 체지방 감소 및 내장지방감소, 간 조직내의 지방량 감소등을 확인하였으며, 혈액분석을 통해 총콜레스테롤과 고중성지방등 동맥경화와 심혈관계 질환을 유도시킬수 있는 지표들에서 억제 활성도 확인하였다. 특히 내장 지방의 경우는 Micro-CT를 통해 정밀한 분석을 진행하였고, 체지방뿐만 아니라 전체 체중감소도 나타나는 것을 확인하였다. 현재 실험을 통해 적출된 간 조직과 지방조직을 이용하여 항 비만 활성의 작용기전을 지속적으로 확인하고 있으며, 이 결과는 국제적인 연구저널에 보고되어 향후 체지방 감소 또는 항 비만 치료제로 개발되는 비임상 연구자료로 활용될 계획이다. 이미 조팝나무에 대한 연구결과는 특허로 출원이 완료되어 PCT출원까지 진행중에 있으며 개별인정형 건강기능식품 개발 기업에 기술이전이 될 예정이다. 또한 원활한 원료 수급을 위해 기초단체 소속 농업기술센터와 원료 재배 및 대량 수급에 관한 논의를 마친 상태로 접경지역 근처 농가소득 증대로도 이어지는 제품화 사례이기도 하다. 이는 접경지역에서 자생하는 원료의 활성을 과학적으로 검증하여 기업과의 연계를 통해 기초시군 단체의 농가 소득과도 연계한 우수한 제품개발 사례로 향후에도 이와 같은 연구성과가 지속적으로 도출되기를 기대해본다.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2020.12a
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• pp.66-66
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• 2020

쌈채소나 산나물로 알려진 곤달비(Ligularia stenocephala)의 종자나 종묘는 시장 거래가격이 높게 형성되어 재배농가의 경영비 증가로 이어지고 있다. 또한, 곤달비의 종자는 대개 농가 자가 채종으로 생산되며, 채종재배에 대한 체계가 정립되어 있지 않다. 이에 본시험은 곤달비의 우량종자 생산을 위한 종자결실률 향상 재배조건과 채종적기를 구명하고자 하였다. 전북 남원시 허브산채시험장에서 2018년 10월에 2년생 곤달비 종묘를 포장에 정식하여 시험을 실시하였다. 적정 채종 재배조건을 구명하기 위해 2019년 노지, 하우스, 55% 차광막을 설치한 노지포장에서 곤달비의 개화시기, 개화율, 생육특성, 결실률 등을 조사하였다. 더불어 채종적기를 설정하기 위해서 곤달비 개화 후 50일~100일 동안 7일 간격으로 채종하여 결실률, 채종량, 종자 발아율을 조사하였다. 곤달비의 개화는 하우스재배, 노지재배의 경우 7월 하순, 차광재배는 8월 초순 개화가 시작되었으며, 개화 최성기도 하우스재배와 노지재배가 차광재배와 비교해 15일 정도 일렀다. 하지만 개화 종료 시기는 노지재배가 가장 빨랐으며 하우스재배가 가장 늦었다. 개화율은 하우스재배, 차광재배, 노지재배 순으로 높았다. 개화기 생육특성는 차광재배일 때 초장과 화경장이 가장 컸으며, 화서수와 자방수는 하우스재배가 타 재배방법에 비해 다소 많았다. 곤달비 재배방법에 따른 결실률은 차광재배가 70.1%, 노지재배가 21.9%, 하우스재배가 15.8%이었으며, 채종량은 차광재배의 경우 10a당 39.6kg, 노지재배 4.9kg, 하우스재배 4.6kg이었다. 백립중과 종자길이, 종자너비 또한 차광재배가 타 재배방법에 비해 양호하였다. 채종시기에 따른 결실률은 채종시기가 늦어질수록 높은 값을 가졌으나, 화경당 채종량은 개화 후 70일에 85일 사이에 가장 많았다. 발아율은 노지재배의 경우 개화 후 70일 이후부터 90% 이상으로 높은 발아율을 보였고, 차광재배는 개화 후 65일부터 95% 이상의 발아율을 나타냈으나 하우스재배의 경우에는 개화 후 80일 이후부터 85% 이상으로 발아율이 양호하였다. 따라서 곤달비의 우량종자를 생산하기 위해서는 55% 차광막을 설치한 노지에서 재배하여 개화 후 65일 이후부터 종자가 비산하기 전까지 채종해야 할 것으로 여겨진다.

• Journal of the Korea Institute of Building Construction
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• v.24 no.2
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• pp.203-213
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• 2024

This study delves into the mechanical properties of fiber-reinforced cement composites(FRCC) concerning the dispersion method of multi-walled carbon nanotubes(MWCNTs). MWCNTs find utility in industrial applications, particularly in magnetic sensing and crack detection, owing to their diverse properties including heat resistance and chemical stability. However, current research endeavors are increasingly directed towards leveraging the electrical properties of MWCNTs for self-sensing and smart sensor development. Notably, achieving uniform dispersion of MWCNTs poses a challenge due to variations in researchers' skills and equipment, with excessive dispersion potentially leading to deterioration in mechanical performance. To address these challenges, this study employs ultrasonic dispersion for a defined duration along with PCE surfactant, known for its efficacy in dispersion. Test specimens of FRCC are prepared and subjected to strength, drawing, and direct tensile tests to evaluate their mechanical properties. Additionally, the influence of MWCNT dispersion efficiency on the enhancement of FRCC mechanical performance is scrutinized across different dispersion methods.

• Journal of Radiation Protection and Research
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• v.40 no.1
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• pp.10-16
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• 2015

Bone changes are common sequela of irradiation in growing animal. The purpose of this study was to establish an experimental model of radiation-induced bone loss in growing mice using micro-computed tomography (${\mu}CT$). The extent of changes following 2 Gy gamma irradiation ($2Gy{\cdot}min^{-1}$) was studied at 4, 8 or 12 weeks after exposure. Mice that received 0.5, 1.0, 2.0 or 4.0 Gy of gamma-rays were examined 8 weeks after irradiation. Tibiae were analyzed using ${\mu}CT$. Serum alkaline phosphatase (ALP) and biomechanical properties were measured and the osteoclast surface was examined. A significant loss of trabecular bone in tibiae was evident 8 weeks after exposure. Measurements performed after irradiation showed a dose-related decrease in trabecular bone volume fraction (BV/TV) and bone mineral density (BMD), respectively. The best-fitting dose-response curves were linear-quadratic. Taking the controls into accounts, the lines of best fit were as follows: BV/TV (%) = $0.9584D^2-6.0168D+20.377$ ($r^2$ = 0.946, D = dose in Gy) and BMD ($mg{\cdot}cm^{-3}$) = $8.8115D^2-56.197D+194.41$ ($r^2$ = 0.999, D = dose in Gy). Body weight did not differ among the groups. No dose-dependent differences were apparent among the groups with regard to mechanical and anatomical properties of tibia, serum ALP and osteoclast activity. The findings provide the basis required for better understanding of the results that will be obtained in any further studies of radiation-induced bone responses.