Geometry-dependent MITC method for a 2-node iso-beam element

이필승,Hyuk-Chun No,Chang-Koon Choi 국제구조공학회 2008 Structural Engineering and Mechanics, An Int'l Jou Vol.29 No.2

In this paper, we present an idea of the geometry-dependent MITC method. The simple concept is exemplified to improve a 2-node iso-beam (isoparametric beam) finite element of varying section. We first study the behavior of a standard 2-node iso-beam finite element of prismatic section, which has been widely used with reduced integration (or the equivalent MITC method) in order to avoid shear locking. Based on analytical studies on cantilever beams of varying section, we propose the axial strain correction (ASC) scheme and the geometry-dependent tying (GDT) scheme for the 2-node iso-beam element. We numerically analyze varying section beam problems and present the improved performance by using both ASC and GDT schemes.

Defect-Free Mixed-Matrix Membranes with Hydrophilic Metal-Organic Polyhedra for Efficient Carbon Dioxide Separation

Yun, Yang No,Sohail, Muhammad,Moon, Jong-Ho,Kim, Tae Woo,Park, Kyeng Min,Chun, Dong Hyuk,Park, Young Cheol,Cho, Churl-Hee,Kim, Hyunuk Wiley (John WileySons) 2018 Chemistry - An Asian Journal Vol.13 No.6

Dietary Exposure and Risk Assessment of Mercury from the Korean Total Diet Study

Kwon, Young Min,Lee, Haeng Shin,Yoo, Dong Chul,Kim, Chun Huem,Kim, Gi Sun,Kim, Ji Ae,Lee, Yu Na,Kim, Young Soon,Kang, Kyung Mo,No, Ki Mi,Paek, Ock Jin,Seo, Jung Hyuk,Choi, Hoon,Park, Sung Kug,Choi, Do Informa UK (TaylorFrancis) 2009 Journal of toxicology and environmental health. Pa Vol.72 No.21

<P>As a national project, obtaining information on the amount of heavy metal exposure of individuals through food intake is an important basic parameter for risk assessment. This study was conducted to evaluate dietary exposure levels and various risks from mercury (Hg) in Korean foods. In total, 342 samples comprising 114 food items were collected and then cooked prior to analysis. As found by Hg analysis, the mean content of metal in the fish and shellfish group was highest among the 15 Korean food groups. The total daily amount of Hg intake from typical Korean foods was 2.40 mug/person/d. The daily amount (mug/person/d) of Hg intake from each food group was 0.155 in grains and cereals, 0.008 potatoes and starch, 0.005 sugars and sweets, 0.0093 pulses, 0.0018 nuts and seeds, 0.203 vegetables, 0.027 fruits, 0.021 meats and poultry, 0.004 eggs, 1.826 fish and shellfish, 0.022 seaweed, 0.043 milk and dairy products, 0.008 oils and fats, 0.042 beverages, and 0.023 seasonings. The fish and shellfish group contributed most to total dietary intake at 76%. For risk assessment, probable daily intake (PDI) was calculated and compared with provisional tolerable weekly intake (PTWI) of the Joint FAO/WHO Expert Committee on Food Additives (JECFA). The level of Hg intake through fish and shellfish of 0.001 mg/kg body weight bw/wk corresponded to 4.54% of the PTWI value of 0.005 mg/kg bw/wk, the safety standard for JECFA. The level of Hg intake through selected foods from the Food list for Koreans was 0.001 mg/kg bw/wk, corresponding to 5.95% of PTWI value. Therefore, overall intake was at levels below the recommended JECFA levels. The relative gender Hg hazard from Korean foods was 6.26% and 5.5% for males and females, respectively. The relative age Hg hazard from Korean foods was, 8.9% in those 3-6 yr old, 6.7% in those 7-12 yr old, 5.2% in those 13-19 yr old, 5.9% in those 20-29 yr old, 6.3% in those 30-49 yr old, 5.6% in those ages 50-64 yr, and 3.7% in the group of those over 65 yr of age. Relative regional Hg hazard from Korean foods was 6.3% in urban versus 5.5% in rural areas. Thus, the amount of Hg intake through consumption of Korean foods was found to be at a relatively safe level. These data may be thus used to establish safety standards for fish and shellfish consumption.</P>

허혈성 심질환과 정상인의 운동부하 검사상 심박수 변화량 및 변화율의 차이

주동욱,강현재,김선웅,노태묵,손혁수,강병준,김새롬,이봉렬,정병천,이종주 대한내과학회 2004 대한내과학회지 Vol.66 No.6

목적 : 허혈성 심질환에서 운동부하 검사시 부교감신경계 재활성의 억제 정도가 반영되어 최고 운동 후 회복기 심박수의 변화량 및 변화율이 정상인보다 억제되는지를 알아보고 이에 따른 심실성 빈맥의 발생에 차이가 있는지를 고찰하였다. 부가적으로 허혈성 심질환에서 심근의 탈분극을 반영하는 R 파의 진폭의 변화가 정상인과 차이가 있는지 알아보았다. 방법 : 운동부하 검사는 연령 및 성별로 보정한 최대 심박수의 85% 이상을 적정 목표 심박수로 하여 Marquette사 case 8000 모델(미국)을 이용해 modified Bruce protocol로 시행하였다. 혈압, 심박수 및 심전도의 측정은 운동부하 전 기립위와 앙와위에서 측정하였으며 운동부하시는 매 3분 간격으로 답차운동의 단계가 증가할 때와 최대 운동시에 측정하였고, 회복기에는 각 1분, 3분, 5분 및 필요시 연장하여 측정하였다. 심박수의 변화량은 각 단계별 심박수로 그 전단계의 심바수를 뺀 절대값으로 하였으며, 심박수의 변화율은 각 단계별 변화량을 그 전단계의 심박수로 나눈 값을 백분율로 하였다. 또한 운동에 따른 부정맥의 발생 양상 및 빈도를 평가하기 위하여 안정시 심전도와 운동부하 검사를 시행하는 동안 및 회복기로 각각의 구간을 나누어 각 구간 중에 부정맥의 발생 유무와 종류, 빈도를 측정하였다. 안정시와 최대 운동시를 비교한 R 파 크기의 변화는 aVF 유도에서 대조군은 0.107±0.3403 mV였고, 양성군은 0.022±0.3771 mV로 두 군간에 유의한 차이를 보이지 않았으며(p=0.106), V5 유도에서도 대조군은 0.034±0.3439 mV였고, 양성군은 0.018±0.5061 mV로 두 군간에 유의한 차이를 보이지 않았다(p=0.782). 결과 : 전체 253명 중 남자 106명, 여자 147명이었으며, 남녀를 포함하여 대조군 196명(남자 78명, 여자 118명)이였고, 양성군 57명(남자 28명, 여자 29명)이었다. 평균 연령은 대조군 55±8.8세였고, 양성군 58±9.4세로 비슷하였다(p>0.05). 양군의 운동량은 양성군 8.1±2.5METs으로 대조군 10.5±2.3METs 보다 낮았다(p<0.001). 안정 심박수는 대조군 69±11회/분이였고, 양성군 70±13회/분으로 차이가 없었으나(p=0.630), 최대 운동부하시 심박수는 양성군 136±22회/분으로 대조군 155±18회/분보다 낮았다(p<0.001). 회복기 심박수는 양성군에서 회복기 1분에 105±23회/분, 3분에 86±15회/분, 5분에 85±15회/분으로 대조군의 회복기 1분에 116±16회/분, 3분에 93±13회/분, 5분에 89±12회/분에 비하여 모두 유의하게 낮았다(p=0.000, p=0.001, p=0.048). 심박수의 변화량은 양성군에서 최대 운동 후 1분일 Ep 31±14회/분, 3분일 때 19±12회/분, 5분일 때 2±4회/분으로 대조군의 최대 운동 후 1분일 때 39±10회/분, 3분일 때 23±9회/분, 5분일 때 6±7회/분에 비하여 낮았다(p<0.001, p=0.008, p=0.002). 심박수의 변화율은 양성군에서는 최대 운동 후 1분일 때 23±10%, 3분일 때 17±8%, 5분일 때 2±5%로 대조군의 최대 운동 후 1분일 때 25±6%, 3분일 때 20±7%, 5분일 때 5±6%에 비하여 낮았다(p=0.017, p=0.027, p=0.002). 심실성 부정맥 유무는 운동전후에 각각 비교시 양군간에 빈도의 차이가 없었고, 중증 심실조기수축의 빈도도 양군간에 유의한 차이가 없었다. 안정시와 최대 운동시를 비교한 R 파 크기의 변화는 aVF 유도에서 대조군과 양성군은 각각 0.107±0.3403 mV와 0.022±0.3771 mV였고, V5 유도에서는 각각 0.034±0.3439 mV와 0.018±0.561 mV로 차이를 보이지 않았다(p=0.106, p=0.782). 결론 : 운동 전후 심박수의 변화량과 변화율로 측정한 부교감신경의 활성정도는 허혈성 심질환이 있는 군과 정상인 간에서 차이를 보이며, 허혈성 심질환이 있는 군의 변화량과 변화률이 유의하게 적었다. 그러나 양군내 심실성 부정맥의 유무나 발생빈도에는 유의한 차이가 없었다. Background : The goal of this study is to evaluate the differences of the rate and the ratio of heart rate changes, which is well known to reflect the vagal reactivation, after peak exercise between ischemic heart disease and normal during treadmill exercise test. Additionally R-wave amplitude changes are evaluated to have the discriminal power between ischemic heart disease and normal. Methods : We have studied 253 human (196 control, 57 patients) who took the symptom-limited exercise test using Marquette case 8000 model. The 57 patients who showed the positive result by exercise test have confirmed by coronary angiography. The rate of heart rate changes was defined as the absolute difference of the heart rate subtracted by the just-previous stage heart rate. The ratio of heart rate changes was defined as the percentile of the rate of heart rate changes comparing to the just-previous stage heart rate. The changes of R-wave amplitude at lead V5 and aVF were obtained by the subtraction of R-wave amplitude at the peak exercise stage from that at the standing rest stage respectively. Additively heart rate recovery was deined as the rate of heart rate change which was obtained at 1 minute later after peak exercise. Results : In patients and control, the resting heart rate were 70±13 bpm and 69±11 bpm (p>0.05), and the peak heart rate were 136±22 bpm and 155±18 bpm respectively (p<0.001). The rate of heart rate changes in patients group were significantly lower than that in control at 1 minute, 3 minute, and 5 minute respectively (p<0.001, p=0.008, p=0.002). The ratio of heart rate changes in patients group were also significantly lower than that in control at 1 minute, 3 minute, and 5 minute respectively (p=0.017, p=0.027, p=0.002). With comparing both groups, the incidences of ventricular ectopy were not different during exercise and recovery stages, and the difference in the changes of R-wave amplitude at lead V5 and aVF were not observed respectively. Conclusion : The rate and ratio of heart rate changes are significantly lower in iscemic heart disease than in normal, and these are resulted from the depression of vagal reactivation. These findings are supplemental to make a diagnosis and a arrhythmic risk stratification of ischemic heart disease.