Static and dynamic mechanics analysis on artificial hip joints

DONGSUN LEE,Fethma,Joong Yeon Yim,Junseok Kim 한국산업응용수학회 2009 한국산업응용수학회 학술대회 논문집 Vol.4 No.2

The purpose of this paper is to present the optimization of appearance and displacement of the prostheses. Artificial hip joints would reduce pains as well as restore walking motion. But dislocation and wearness of this are considered as serious side effects of the surgical replacement beyond the prostheses’ excellent performance. New design based on mathematical model for an artificial hip joint will elongate lifetime and provide much more natural movement by engaging forces. And to manipulate model parameters such as the radius of femoral and acetabular cup and structural support, we take advantage of ABAQUS 6.8-1 which is a finite element solver used for stress strain and types of in mechanical and structural analysis. The finite element method was employed in this paper to compare.

NUMERICAL ANALYSIS OF CELL GROWTH IN SCAFFOLDS

Dongsun Lee,Darea Jeong,Hyun Geun Lee,Junseok Kim 한국산업응용수학회 2009 한국산업응용수학회 학술대회 논문집 Vol.2009 No.5

A mathematical model to predict the growth of cells is a powerful tool in scaffold designing. The improved understanding derived from this mathematical model and its numerical analysis are useful in the design of three-dimensional scaffolds that can support more confirm growth of cells.

Hepatoprotective Effect of a Preparation of Combined Glutathione- Enriched Yeast and Rice Embryo/Soybean Extracts

Dongsun Park,Heon-Sik Lee,Tae Myoung Kim,Jugyeong Song,Jeong Hee Jeon,Sunhee Shin,Seong Soo Joo,Hyoung Kook Park,Won Kyung Lee,Jin Tae Hong,Yun-Bae Kim 한국실험동물학회 2009 Laboratory Animal Research Vol.25 No.1

The effects of GEY+RES, a preparation of combined glutathione-enriched yeast (GEY) and rice embryo/soybean (RES) extracts (20:1), on carbon tetrachloride (CCl₄)-induced hepatic injury were investigated in male Sprague-Dawley rats. The rats were orally administered with GEY+RES at low (GEY+RES=50+2.5 ㎎/㎏), medium (100+5 ㎎/㎏) or high (200+10 mg/kg) doses for 2 weeks, followed by intraperitoneal challenge with CCl₄ (1 mL/㎏) 30 min after the final treatment. Twenty four hours later, initial biliary excretion and time-course of blood concentration of intravenously-injected bromosulphalein were examined. In addition, blood parameters of hepatic injury in accordance with histopathological findings were analyzed. The biliary excretion time and clearance of bromosulphalein were greatly delayed by CCl₄ injection, which were recovered by GEY+RES in a dose-dependent manner, resulting in decreases to a half level by medium and high doses. CCl₄ drastically increased the blood markers of hepatotoxicity, and caused centrilobular congestion, hepatocytic degeneration, lipid droplets and inflammatory cell infiltration, leading to disintegration of hepatic cords. The increased biochemical parameters and hepatic lesions induced by CCl₄ were significantly attenuated by GEY+RES treatment. The results suggest that GEY+RES might prevent liver dysfunction induced by CCl₄, and that GEY+RES could be a potential candidate for the prevention of hepatic disorders.

The fractional Allen–Cahn equation with the sextic potential

Lee, Seunggyu,Lee, Dongsun Elsevier 2019 Applied mathematics and computation Vol.351 No.-

<P><B>Abstract</B></P> <P>We extend the classical Allen–Cahn (AC) equation to the fractional Allen–Cahn equation (FAC) with triple-well potential. By replacing the spatial Laplacian and double-well potential with fractional Laplacian and triple-well potential, we observe different dynamics. This study leads us to understand different properties of the FAC equation. We seek the existence, boundedness, and unique solvability of numerical solutions for the FAC equation with triple-well potential. In addition, the inclusion principle for the Allen–Cahn equation is considered. These different properties make us enhance the applicability of the phase-field method to the mathematical modeling in materials science. In computation, the spectral decomposition for the fractional operator allows us to develop a numerical method for the fractional Laplacian problem. For the periodic and discrete Laplacian matrix and vector multiplication, circulant submatices are formed in more than two-dimensional case. Even if the fast Fourier transform (FFT) can be utilized in this modeling, we construct the inverse of the doubly-block-circulant matrix for the solution of the fractional Allen–Cahn equation. In doing so, it helps to straightforwardly understand the numerical treatment, and exploit the properties of the discrete Fourier transforms.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Boundedness of numerical solutions for the fractional Allen – Cahn equation with sextic polynomial is under consideration. </LI> <LI> From the numerical aspect, the inclusion principle is proven to hold only for the Allen – Cahn equation. </LI> <LI> Effects of the fractional order and parameters of the equation is analyzed. </LI> <LI> Eigenvectors of the discrete Laplacian are used for investigating the behaviors of the fractional Allen – Cahn equation. </LI> <LI> The numerical study of the fractional Allen – Cahn equation with the sextic polynomial is verified by various simulations. </LI> </UL> </P>

Antioxidative and Antidiarrheal Effects of Persimmon Extracts

Dongsun Park,Sun Hee Lee,Dae-Kwon Bae,Young Jin Choi,Tea Kyun Kim,Yun-Hui Yang,Goeun Yang,Sang-Chul Kwon,Do Ik Lee,Sung Soo Joo,Yun-Bae Kim 한국실험동물학회 2010 Laboratory Animal Research Vol.26 No.4

Since oxidative stresses are involved in gastroenteritis and diarrhea, we investigated antioxidative and antidiarrheal activities of persimmon flesh extract (PFE) and persimmon calyx extract (PCE) in vitro and in vivo, respectively. PCE significantly scavenged 1,1-diphenyl-2-picrylhydrazyl hydrate and 2,2'-azinobis (3-ethylbenzthiazoline-6-sulfonic acid) from 500 ㎍/mL, although PFE was ineffective. In addition, PFE and PCE exhibited strong nitric oxide-scavenging effects from 1 μg/mL, in which PCE was superior to ascorbic acid (50 μM). Furthermore, PFE and PCE significantly inhibited FeCl3-induced lipid peroxidation as well as Cu<SUP>2+</SUP>/H₂O₂-induced protein oxidation from 10 μg/mL. In vivo charcoal-propulsion assay, in contrast to a negligible effect of PFE, treatment with PCE (160-500 ㎎/㎏) markedly inhibited intestinal motility. The results indicate that extracts of persimmon, especially PCE, possess antioxidative, antiinflammatory and antidiarrheal activities. Therefore, it is suggested that persimmon extracts could be used for the relief of gastroenteritis and diarrhea.

Silk and silkworm pupa peptides suppress adipogenesis in preadipocytes and fat accumulation in rats fed a high-fat diet.

Lee, Sun Hee,Park, Dongsun,Yang, Goeun,Bae, Dae-Kwon,Yang, Yun-Hui,Kim, Tae Kyun,Kim, Dajeong,Kyung, Jangbeen,Yeon, Sungho,Koo, Kyo Chul,Lee, Jeong-Yong,Hwang, Seock-Yeon,Joo, Seong Soo,Kim, Yun-Bae Steinkopff 2012 EUROPEAN JOURNAL OF NUTRITION Vol.51 No.8

<P>The objective was to confirm the anti-obesity activity of a silk peptide (SP) and a silkworm pupa peptide (SPP) in rats fed a high-fat diet (HFD) and to elucidate their action mechanism(s) in a preadipocyte culture system. In an in vitro mechanistic study, the differentiation and maturation of 3T3-L1 preadipocytes were stimulated with insulin (5 mu g/mL), and effects of SP and SPP on the adipogenesis of mature adipocytes were assessed. In an in vivo anti-obesity study, male C57BL/6 mice were fed an HFD containing SP or SPP (0.3, 1.0, or 3.0%) for 8 weeks, and blood and tissue parameters of obesity were analyzed. Hormonal stimulation of preadipocytes led to a 50-70% increase in adipogenesis. Polymerase chain reaction and Western blot analyses revealed increases in adipogenesis-specific genes (leptin and Acrp30) and proteins (peroxisome proliferator-activated receptor-gamma and Acrp30). The hormone-induced adipogenesis and activated gene expression was substantially inhibited by treatment with SP and SPP (1-50 mu g/mL). The HFD markedly increased body weight gain by increasing the weight of epididymal and mesenteric fat. Body and fat weights were significantly reduced by SP and SPP, in which decreases in the area of abdominal adipose tissue and the size of epididymal adipocytes were confirmed by magnetic resonance imaging and microscopic examination, respectively. Long-term HFD caused hepatic lipid accumulation and increased blood triglycerides and cholesterol, in addition to their regulatory factors Acrp30 and leptin. However, SP and SPP recovered the concentrations of Acrp30 and leptin, and attenuated steatosis. SP and SPP inhibit the differentiation of preadipocytes and adipogenesis by modulating signal transduction pathways and improve HFD-induced obesity by reducing lipid accumulation and the size of adipocytes.</P>

Human neural stem cells overexpressing choline acetyltransferase restore cognitive function of kainic acid-induced learning and memory deficit animals.

Park, Dongsun,Joo, Seong Soo,Kim, Tae Kyun,Lee, Sun Hee,Kang, Hyomin,Lee, Hong Jun,Lim, Inja,Matsuo, Akinori,Tooyama, Ikuo,Kim, Yun-Bae,Kim, Seung U Pergamon Press ; Elsevier Science Ltd ; Elsevier S 2012 Cell transplantation Vol.21 No.1

<P>Alzheimer disease (AD) is a progressive neurodegenerative disease, which is characterized by loss of memory and cognitive function. In AD patients dysfunction of the cholinergic system is the main cause of cognitive disorders, and decreased activity of choline acetyltransferase (ChAT), an enzyme responsible for acetylcholine (ACh) synthesis, is observed. In the present study we investigated if brain transplantation of human neural stem cells (NSCs) genetically modified to encode ChAT gene improves cognitive function of kainic acid (KA)-induced learning deficit rats. Intrahippocampal injection of KA to hippocampal CA3 region caused severe neuronal loss, resulting in profound learning and memory deficit. F3.ChAT human NSCs transplanted intracerebroventricularly improved fully the learning and memory function of KA-induced learning deficit animals, in parallel with the elevation of ACh levels in cerebrospinal fluid. F3.ChAT human NSCs migrated to the KA-induced injury site (CA3) and differentiated into neurons and astrocytes. The present study demonstrates that human NSCs expressing ChAT have lesion-tropic property and improve cognitive function of learning deficit model rats with hippocampal injury by increasing ACh level.</P>

법인 아닌 사단의 공시방안에 관한 연구

이동선 ( Lee Dongsun ) 사법정책연구원 2019 연구보고서 Vol.2019 No.10

본 연구는 권리능력은 없지만 현실에서는 권리주체로서 활동하고 있는 법인 아닌 사단의 현황을 살피고, 독일, 프랑스, 일본 등 해외사례를 비교·검토한 다음 법인 아닌 사단을 둘러싼 문제점에 대한 해결책으로 법인 아닌 사단의 공시방안을 모색하고자 하였다. 본 연구에서는 법인 아닌 사단의 공시방안을 크게 등기를 통한 방안과 등록을 통한 방안으로 나눠 살펴본 후, 실현 가능성과 실효성 면에서 우수한 것으로 생각되는 등록을 통한 공시방안을 최종적 대안으로 제시하였다. 등록을 통한 공시방안은 현재의 부동산등기용등록번호를 이용하여 공시를 하는 방안을 말한다. 이 방안에서는 법인 아닌 사단이 부동산등기신청을 할 경우 정관이나 사원총회결의서 등에 참석공증을 받도록 하여 법인 아닌 사단의 실체성과 대표자의 진정성을 담보할 수 있도록 하였고, 등기관이 등기를 완료한 후에는 법인 아닌 사단의 명칭, 사무소소재지, 대표자에 관한 사항 등이 기록된 법인 아닌 사단 등록부를 작성하게 하였다. 본 연구에서 제시한 방안이 정책으로 이어진다면 결국 부동산을 가지고 있는 법인 아닌 사단은 모두 등록부를 통하여 공시되고, 소송이나 비송 기타 거래 실무에서는 ‘법인 아닌 사단 등록사항증명서’가 사단의 실체성이나 대표자의 진정성을 소명하는 자료 역할을 함으로써 법인 아닌 사단의 거래 안전이 더욱 강화될 것으로 생각된다. 본 연구가 향후 법인 아닌 사단의 공시방안 논의의 활성화에 조금이나마 기여할 수 있기를 바란다. The purpose of this study is to examine the current status of unincorporated associations that do not have capacity of enjoyment of rights, but in reality, act as a subject of rights. This study compares and reviews the cases of Germany, France, and Japan, and explores the methods of public disclosure of unincorporated associations to address issues regarding unincorporated associations. In this study, two methods of public disclosure of an unincorporated association―public disclosure by (1) registration of information on the association in the corporate register, premised on incorporation of the unincorporated association and by (2) entry of information on the unincorporated association, obtained in the application process for an identification number of the association for real estate registration or other purposes, in a new kind of register on unincorporated associations―are examined. Following a thorough examination, the second method, that is considered superior to the first one in terms of its feasibility and effectiveness, is presented as the most proper measure. According to the method, for an unincorporated association to apply for real estate registration, its articles of association or resolutions at a general meeting of the members of the association must be notarized― by a notary public who observed in person the general meeting―in order to ensure the substantiality of the unincorporated association and the veracity of its representative(s). A registration officer must enter information on an unincorporated association in a register on unincorporated associations―separate from the real estate register in the case of real estate registration―detailing the name of the association, office location, and matters related to its representative(s). If the method of public disclosure proposed in this study is mandated by policy, then all unincorporated associations holding real estate will be disclosed through the register mentioned above. Furthermore, in the context of litigation and non-contentious procedure cases as well as other transactions, an “unincorporated association registration certificate” will be utilized to verify the substantiality of the body and/or the veracity of its legal representative(s), thereby further strengthening the transaction security involving unincorporated associations. It is hoped that this study will contribute to facilitating future discussions on the methods of public disclosure of unincorporated associations.

저가형 IMU와 GPS수신기를 이용한 자세결정 시스템

이동선(DongSun Lee),채정근(JeongGeun Chae),이민준(Min-joon Lee),박찬식(Chansik Park) 대한전기학회 2014 대한전기학회 학술대회 논문집 Vol.2014 No.7

Moving Base 모드를 지원하는 수신기를 이용한 무인기 사이의 상대 측위 결과 분석

이동선(DongSun Lee),박귀우(Kwi Woo Park),강권우(Kang Gwon U),박일규(IL-Kyu Park),손석보(Son Seok Bo) 한국통신학회 2020 한국통신학회 학술대회논문집 Vol.2020 No.2