Dual growth factor delivery using core PLGA-shell alginate microcapsule for angiogenesis

최동훈,라메쉬,박귀덕 한국고분자학회 2013 한국고분자학회 학술대회 연구논문 초록집 Vol.2013 No.4

누리다 볼 운동이 중년 남성의 근기능, 척추정렬 및동적 균형능력에 미치는 영향

최동훈,김태경,박재명,정종환,염동철,조인호,조준용,구정훈 한국응용과학기술학회 2020 한국응용과학기술학회지 Vol.37 No.6

The purpose of this study was to investigate the effect of Nurida-Ball exercise on isokinetic muscle function, spinal alignment, and dynamic balance capacity in middle-aged men. All middle-aged men(n=16) were divided into 2 groups: Ball exercise(BE, n=8) and control(CON, n=8) group. BE group performed the Nurida-Ball exercise(30 min/day, 3 days/week, 8 weeks) and isokinetic knee and trunk muscle function, spinal alignment, and dynamic balance capacity were measured. All of the measured variables calculated the mean and standard deviation and verified normality using the Shapiro-Wilk test. The independent t-test method and the Paired t-test method were then analyzed to identify differences between groups. This study found that isokinetic knee and trunk muscle function was significantly strengthened in the BE compared with CON group by increasing peak torque(PT) of right and left knee extension(60°/sec, p<0.01, respectively), average power(AP) of right and left knee extension(60°/sec, p<0.05, p<0.01, respectively), and PT of right knee flexion(180°/sec, p<0.05) and AP of right knee extension(180°/sec, p<0.05). In the change of isokinetic trunk muscle function, only PT of trunk extension(180°/sec) was increased in the BE compared with the CON group(p<0.05). In addition, Nurida-ball exercise can improve the spinal alignment by reducing the trunk inclination(p<0.05) in the BE compared with the CON group. Finally, dynamic balance capacity was also enhanced in the BE compared with the CON group by decreasing the score of overall balance index(OBI, p<0.01) and Antero-posterior balance index(p<0.05) in the Stage-6, and OBI(p<0.05) in the Stage-1. This result demonstrated that Nurida-ball exercise may improve spinal alignment, dynamic balance capacity, and isokinetic muscle function, which might be an effective way for the improvement of health-related fitness in middle-aged men. 본 연구는 8주간의 누리다 볼 운동이 중년 남성들의 등속성 근기능, 척추 정렬 및 동적 균형 능력에 미치는 영향을 규명하는데 있다. 본 연구의 대상자는 중년 남성(n=16)을 공 운동 그룹(BE, n=8)과 비교 그룹(CON, n=8)으로 구분하였으며 BE 그룹은 하루 30분, 주 3회, 총 8주간 누리다 볼 운동을 실시 하여 등속성 슬관절 및 체간의 근 기능, 척추 정렬 및 동적 균형 능력을 측정하였다. 측정된 모든 변인들은 평균과 표준편차를 산출하고, Shapiro-Wilk test를 이용하여 정규성 검증을 확인하였다. 이후 집단 간의 차이를 확인하기 위해서 독립(Independant) t-test 방법과 대응(Paired) t-test 방법을 이용하여 분석하였다. 본 연구의 결과, 등속성 슬관절 및 체간 근 기능은 CON 그룹과 비교하여 BE 그룹에서 좌측과 우측의 슬관절 신전근의 피크파워(%BW, 60°/sec, p<.001, respectively), 좌측과 우측 슬관절 신전근의 평균파워 (%BW, 60°/sec, p<.05, p<.001, respectively), 우측 슬관절 굴골근의 피크파워(%BW, 180/sec, p<.05) 및우측 슬관절 신전근의 평균파워(%BW, 180°/sec, p<.05)가 유의하게 증가하는 것으로 나타났다. 등속성 체간의 근 기능 변화량은 CON 그룹과 비교하여 BE 그룹에서 신전근의 피크토크(%BW, 180/sec, p<.05) 가 유의하게 증가하는 것으로 나타났다. 또한, 누리다 볼 운동은 몸통 앞뒤 기울기를 감소시켜 척추 정렬을 일부 개선한 것으로 나타났다(p<0.05). 마지막으로 CON 집단과 비교하여 BE 집단에서 동적 균형 능력은 6 단계의 전체균형지수(p<0.01), 전후균형지수(p<0.05) 및 1단계의 전체균형지수(p<0.05)를 유의하게 감소 시켰다. 따라서 연구를 종합해 보면 누리다 볼 운동은 중년 남성들에게 있어 등속성 근 기능, 척추 정렬 및동적 균형 능력과 같은 건강 관련 체력을 향상 시킬 수 있는 효과적인 운동 기구라고 사료되며, 향후 운동의 형태(강도, 빈도 등)를 다양하게 적용한 후속 연구가 필요할 것이다.

탄성유체윤활이론을 적용한 볼 베어링 역학

최동훈 대한기계학회 1989 大韓機械學會誌 Vol.29 No.3

볼 베어링의 성능에 중요한 영향을 미치는 볼 베어링 특유의 기하학적 형상, 탄성론에 근거한 볼과 궤도륜 사이의 접촉역학 및 구름접촉을 위한 탄성 유체윤활이론을 소개한 후, 축방향 하 중하에서 고속으로 회전하고 있는 볼 베어링의 해석방법을 기술하였다. 소개된 해석 방법이 완박한 것은 아니며, 보다 엄밀한 해석을 위하여 마찰열에 의한 온도상승의 영향을 고려하여야 할 것이다. 또한 해석 결과를 얻기 위하여 효율적인 수치 계산법을 적용한 볼 베어링 해석을 위한 결과를 얻기 위하여 효율적인 수치 계산법을 적용한 볼 베어링 해석을 위한 전용 소프트 웨어를 개발하여야 한다. 외국에서는 이와 같은 컴퓨터 프로그램이 사용되고 있으나, 우리도 독자적으로 전용 소프트웨어를 개발함으로써, 외국의 소프트웨어를 도입하였을 때의 한계를 피 하고, 다양한 응용예마다 가장 효율적인 해석을 할 수 있는 유연성을 가질 필요가 있다고 생각 한다. 구조물 최적설계를 위하여 유한요소 해석 프로그램을 이용하듯이, 이와 같은 전용 해석 소프트웨어를 사용하여 볼 베어링의 최적설계를 할 수 있을 것이다.

관수된 충전칼럼에서의 압력손실

최동훈,신남철,김장호 동아대학교 환경문제연구소 1998 硏究報告 Vol.21 No.1

In this work, an equation for determining the pressure drop of irrigated packings is introduced. This is built up from the well-known channel model. It is valid for the whole load range up to the flooding point. To apply the pressure drop formula, it is necessary to know the operating conditions, the liquid hold-up and the from factor μ specific to the packing element or group of packings. The method of calculating the pressure drop is illustrated by means of an example 1) The agreement obtained between the calculations and the experiments is regarded as good. As expected, the measurements below the loading line are reproduced more exactly-the average error ￣δ₁(△P/H) in Table l(a)-(c) is considerably less than 10%. The measurements above the loading limit including the pressure drop at the flooding point are reproduced with an average relative error ￣δ₂(△P/H) of about 15%. 2) Another advantage of the method chosen here the represent the pressure drop is that, by means of a packings element constant μ characteristic of almost every family of packing elements or group of packing elements of similar construction, it is easy to compare the pressure drop of the particular type of packing element and its height with other packing elements. The advantage of this model is that know-ledge of the dry pressure drop of the packing is not necessary. To reinforce the above dependences a numerical example is added with the help of which the determination of the pressure drop is demonstrated.

Cone beam CT를 이용한 비글견 발치창 치유과정에 대한 방사선학적 연구

최동훈,이완,김대석,이병도 대한구강악안면방사선학회 2009 Imaging Science in Dentistry Vol.39 No.1

Purpose : To longitudinally observe the healing process of extracted socket and the alterations of the residual ridge in healthy adult dogs using cone beam CT (CBCT). Materials and Methods : The mandibular premolars of two beagle dogs were removed and the extraction sites were covered with the gingival tissue. CBCTs (3D X-ray CT scanner, Alphard vega, Asahi Co.) were taken at baseline and at 1 week interval for 12 weeks. Radiographic density of extracted wounds was measured on normalized images with a custom-made image analysis program. The amount of alveolar crestal resorption after the teeth extraction was measured with a reformatted three-dimensional image using CBCT. Bony healing pattern of extracted wound of each group was also longitudinally observed and analyzed. Results : Dimensional changes occurred during the first 6 weeks following the extraction of dogs’ mandibular premolars. The reduction of the height of residual ridge was more pronounced at the buccal than at the lingual aspect of the extraction socket. Radiographic density of extracted wounds increased by week 4, but the change in density stabilized after week 6. New bone formation was observed at the floor and the peripheral side of extracted socket from week 1. The entrance of extracted socket was sealed by a hard-tissue bridge at week 5. Conclusion : The healing process of extracted wound involved a series of events including new bone formation and residual ridge resorption.

고려대학교 화학인재양성사업단

최동훈 한국고분자학회 2014 고분자 과학과 기술 Vol.25 No.3

테마기획 다분야 통합 최적화 기술 : 다분야 통합 최적설계 개념과 중요성

최동훈 대한기계학회 2000 기계저널 Vol.40 No.3

The Beneficial Effect of Renin-Angiotensin- Aldosterone System Blockade in Marfan Syndrome Patients after Aortic Root Replacement

최동훈,이승준,오재원,고영국,이삭,장병철,이도연,곽영란 연세대학교의과대학 2016 Yonsei medical journal Vol.57 No.1

Purpose: In this study, we evaluated the long term beneficial effect of Renin-Angiotensin-Aldosterone System (RAAS) blockadetherapy in treatment of Marfan aortopathy. Materials and Methods: We reviewed Marfan syndrome (MFS) patients who underwent aortic root replacement (ARR) betweenJanuary 1996 and January 2011. All patients were prescribed β-blockers indefinitely. We compared major aortic events includingmortality, aortic dissection, and reoperation in patients without RAAS blockade (group 1, n=27) to those with (group 2, n=63). Theaortic growth rate was calculated by dividing the diameter change on CT scans taken immediately post-operatively and the latestscan available. Results: There were no differences in clinical parameters except for age which was higher in patients with RAAS blockade. Ingroup 1, 2 (7%) deaths, 5 (19%) aortic dissections, and 7 (26%) reoperations occurred. In group 2, 3 (5%) deaths, 2 (3%) aortic dissections,and 3 (5%) reoperations occurred. A Kaplan-Meier plot demonstrated improved survival free from major aortic eventsin group 2. On multivariate Cox, RAAS blockade was an independent negative predictor of major aortic events (hazard ratio 0.38,95% confidence interval 0.30–0.43, p=0.002). Mean diameter change in descending thoracic and supra-renal abdominal aortawas significantly higher in patients without RAAS blockade (p<0.05). Conclusion: In MFS patients who underwent ARR, the addition of RAAS blockade to β-blocker was associated with reduction ofaortic dilatation and clinical events.

음압을 발생시키는 레일을 지닌 헤드슬라이더의 최적설계 방법 ( An Optimization Method for Design of Subambient Pressure Shaped Rail Sliders )

최동훈,강태식 대한기계학회 1998 대한기계학회 춘추학술대회 Vol.- No.-

Optical control of birefringence and electrooptic response of a nematic liquid crystal using an alignment layer of photoresponsive azo copolymer

최동훈,조강진,강석훈,이주현,이신두 한국고분자학회 1999 한국고분자학회 학술대회 연구논문 초록집 Vol.24 No.1