• Journal of Biosystems Engineering
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• 제35권5호
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• pp.357-365
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• 2010

Workers in the agricultural industry have been exposed to many work-related musculoskeletal disorders. So, our objectives in this study were to measure and analyze worker's physiological bio-information to reduce musculoskeletal disorders in relation to agricultural works. We investigated worker's bio-information of physiological signals during the repeated lifting work such as body temperature, heart rate, blood pressure, physical activity, and heart rate variability. Moreover, we analyzed the workloads of lumbar spine during the repeated lifting work using the 3-axis acceleration and angular velocity sensors. The changes of body temperature was not significant, but the mean heart rate increased from 90/min to 116/min significantly during 30 min of repeated lifting work (p<0.05). The average worker's physical activity(energy consumption rate) was 206 kcal/70kg/h during the repeated lifting work. The workers' acute stress index was more than 80, which indicated a stressful work. Also, the maximum shear force on the disk (L5/S1) of a worker's lumbar spine in static state was 500N, and the maximum inertia moment was 139 $N{\cdot}m$ in dynamic state.

• Clinical and Experimental Pediatrics
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• 제53권8호
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• pp.809-813
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• 2010

Bartter syndrome (BS) is an autosomal recessively inherited rare renal tubular disorder characterized by hypokalemic metabolic alkalosis and hyperreninemic hyperaldosteronism with normal to low blood pressure due to a renal loss of sodium. Genetically, BS is classified into 5 subtypes according to the underlying genetic defects, and BS is clinically categorized into antenatal BS and classical BS according to onset age. BS type I is caused by loss-of-function mutations in the $SLC12A1$ gene and usually manifests as antenatal BS. This report concerns a male patient with compound heterozygous missense mutations on $SLC12A1$ (p.C436Y and p.L560P) and atypical clinical and laboratory features. The patient had low urinary sodium and chloride levels without definite metabolic alkalosis until the age of 32 months, which led to confusion between BS and nephrogenic diabetes insipidus (NDI). In addition, the clinical onset of the patient was far beyond the neonatal period. Genetic study eventually led to the diagnosis of BS type I. The low urinary sodium and chloride concentrations may be caused by secondary NDI, and the later onset may suggest the existence of a genotype-phenotype correlation. In summary, BS type I may have phenotype variability including low urine sodium and chloride levels and later onset. A definitive diagnosis can be confirmed by genetic testing.

• 대한의용생체공학회:의공학회지
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• 제40권2호
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• pp.62-67
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• 2019

The purpose of this study was to evaluate the performance of deep neural network model in order to determine whether there is a risk factor for coronary artery disease based on the cardiac variation parameter. The study used unidentifiable 297 data to evaluate the performance of the model. Input data consists of heart rate parameters, which are SDNN (standard deviation of the N-N intervals), PSI (physical stress index), TP (total power), VLF (very low frequency), LF (low frequency), HF (high frequency), RMSSD (root mean square of successive difference) APEN (approximate entropy) and SRD (successive R-R interval difference), the age group and sex. Output data are divided into normal and patient groups, and the patient group consists of those diagnosed with diabetes, high blood pressure, and hyperlipidemia among the various risk factors that can cause coronary artery disease. Based on this, a binary classification model was applied using Deep Neural Network of deep learning techniques to classify normal and patient groups efficiently. To evaluate the effectiveness of the model used in this study, Kernel SVM (support vector machine), one of the classification models in machine learning, was compared and evaluated using same data. The results showed that the accuracy of the proposed deep neural network was train set 91.79% and test set 85.56% and the specificity was 87.04% and the sensitivity was 83.33% from the point of diagnosis. These results suggest that deep learning is more efficient when classifying these medical data because the train set accuracy in the deep neural network was 7.73% higher than the comparative model Kernel SVM.

• 한국산림과학회지
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• 제113권1호
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• pp.107-117
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• 2024

본 연구는 시간에 따른 산림환경의 물리환경요소 변화와 이에 따른 온열환경 쾌적성, 인체의 생리·심리적 반응의 차이를 종합적으로 규명하기 위하여 수행되었다. 9시부터 18시까지 산림환경의 물리환경요소(공기온도, 평균복사온도, 풍속, 상대습도)와 예상평균한서감지수(PMV), 예상불만족률(PPD)를 연속 측정하고, 1시간 간격으로 남자 대학생 30명(평균 연령: 21.7±1.9세)이 눈을 감고 5분 동안 안정을 취할 때의 생리·심리적 반응(심박변이도, 심박수, 구강체온, 혈압, 맥박수, 주관적 온열감과 쾌적감 및 인상)을 조사하였다. 더불어 물리환경요소와 생리적 반응 사이의 상관관계를 조사하였다. 그 결과, ① 공기온도, 평균복사온도, 풍속, 상대습도 모두 시간에 따라 유의하게 변화하였다. ② PMV와 PPD도 시간에 따라 유의하게 변화하였다. 주관적 온열감은 PMV와 일치하였으나, 주관적 쾌적감은 PPD와 일치하지 않았다. ③ 생리적 반응 중 ln(HF), ln(LF/HF), 심박수, 이완기혈압이 시간에 따라 유의하게 변화하였다. 공기온도가 가장 높았던 14~16시에 ln(HF)는 가장 낮았고, ln(LF/HF)는 가장 높았다. ④ 공기온도, 평균복사온도, 풍속은 ln(HF)와 음의 상관관계, ln(LF/HF)와 양의 상관관계를 나타내었다. 이를 통해 산림환경을 이용하는 시간대에 따라 이용객의 쾌적감과 생리·심리적 안정 효과가 달라질 수 있으며, 시간에 따른 산림환경의 물리환경요소 변화가 이러한 차이에 영향을 미친다는 사실이 밝혀졌다.

• 한국응용과학기술학회지
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• 제40권4호
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• pp.674-684
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• 2023

스트레스 자극에 대한 심혈관계 및 교감신경계 과활성화 반응은 향후 심혈관계 질환 발생 및 심장 돌연사의 위험을 증가시킨다. 음악 청취는 자율신경계 기능을 향상시켜 안정 시 긴장 이완을 유도하는 것으로 알려져 있으나 음악이 스트레스 상황에서의 과도한 심혈관 반응을 완화 시킬 수 있는지에 대한 연구는 부족하다. 본 연구는 음악청취가 스트레스 자극에 대한 심혈관 반응성을 완화시켜 줄 수 있을지 검증하였다. 15명의 건강한 성인(남자 9명, 여성 6명)을 대상으로 무작위 교차 실험 설계로 진행하였다. 음악 처치는 음악을 30분간 청취하였고 통제 처치는 30분간 휴식을 취하였다. 냉압박 검사로 교감신경계를 자극하였으며, 변인으로 심박수, 상완 및 중심동맥 혈압과 심박변이도(heart rate variability)를 측정하였다. 연구 결과, 음악 처치와 통제 처치 모두 냉압박 검사 중 심박수와 혈압 반응이 유의하게 증가하였으나(p < .001), 처치와 시기 간 상호작용 효과는 유의하지 않았다. 회복 구간에서 상완동맥 수축기혈압이 음악처치 그룹에서만 유의하게 감소하였다(p = 0.008). 나머지 혈압 변인들도 음악중재 그룹에서 더 완화되는 경향이 나타났으나 통계적으로 유의하지는 않았다. 심박변이도는 음악 처치 전후로 음악 처치 그룹에서만 SDNN(standard deviation of the NN intervals), TP(total power)와 HF(high frequency)값이 유의하게 증가하였다(p = 0.001, p = 0.002, p = 0.011). 따라서 음악 청취는 스트레스 이후의 회복력을 촉진시킬 가능성이 있다. 음악 처치의 구체적인 변인들을 고려하여 과도한 심혈관 반응에 대한 보호 효과로서의 음악 청취에 대한 추가적인 연구가 필요하다.

• 한방비만학회지
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• 제9권2호
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• pp.33-45
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• 2009

Objectives This study was performed to evaluate the relation between hair tissue mineral elements(HTME) and Heart rate variability(HRV) of the metabolic syndrome(MS). Methods 89 persons(41-69 ages) who visited Oriental hospital for medical examination were divided MS group(n=22) and control group(n=67). HTME and HRV were compared, and were analyzed correlation with five contents of the MS. Results (1) In total subjects, waist circumference had a positive correlation with Pb. Blood pressure had a negative correlation with Mg. High density lipoprotein cholesterol(HDL-chol) had a negative correlation with Pb, Sb and K, while positive correlation with Ca/K. Triglyceride(TG) had a negative correlation with Mg and Na/K, while positive correlation with K and Ca/Mg. (2) In total subjects, TG and fasting blood sugar(FBS) had negative correlation with high frequency(HF), while positive correlation with low frequency/high frequency ratio(LF/HF). (3) In MS group, most of the level of toxic minerals were higher, and the level of major nutritional minerals were lower, but there were no statistical signficance. In two groups, there is no contrast between the correlations of the MS contents and HTME. (4) In MS group, HF was significantly lower and LF/HF was higher than normal group. LF/HF had a negative correlation with waist circumference in MS group, while positive correlation in normal group. (5) In total subjects, TP had a positive correlation with Mg. In two groups, there is no contrast between the correlations of the MS contents and HRV. However LF/HF had a positive correlation with Na in MS group, TP and LF had negative correlation with Ca, while RMSSD and HF had negative correlation with Cu in normal group. Conclusion These results may suggest that HTME and HRV are useful in diagnosing and preventing the metabolic syndrome.

• Yonsei Medical Journal
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• 제59권9호
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• pp.1138-1142
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• 2018

This study aimed to analyze the impact of sleep deprivation (SD) on cardiac, hemodynamic, and endothelial parameters and to determine whether these are sustained with increased periods of SD. The study included 60 healthy men (mean: age $31.2{\pm}6.3years$; body mass index $24.6{\pm}2.6kg/m^2$). Hemodynamic parameters, parameters of myocardial contractility, spectral analysis of heart rate (HR) and blood pressure (BP) variability, and the sensitivity of arterial baroreflex function were evaluated. Biochemical tests were performed to assess L-arginine (L-Arg) and asymmetric dimethylarginine (ADMA) levels in reflection of endothelial nitric oxide synthase ability. Measurements of cardiovascular system parameters were obtained at 9 a.m. (baseline) on the first day of the study and 9 a.m. (24-h SD), 1 p.m. (28-h SD), and 5 p.m. (32-h SD) on the second day. Blood samples for evaluating biochemical parameters were obtained at baseline and after 24-h SD. ANOVA Friedman's test revealed a significant effect for time in relation to HR (${\chi}^2=26.04$, df=5, p=0.000), systolic BP (${\chi}^2=35.98$, df=5, p=0.000), diastolic BP (${\chi}^2=18.01$, df=5, p=0.003), and mean BP (${\chi}^2=28.32$, df=5, p=0.000). L-Arg and ADMA levels changed from $78.2{\pm}12.9$ and $0.3{\pm}0.1$ at baseline to $68.8{\pm}10.2$ and $0.4{\pm}0.1$ after 24-hr SD, respectively (p=0.001, p=0.004). SD in healthy men is associated with increases in BP, which appear to occur after 24 hours of SD and are maintained over increasing periods of SD. The observed hemodynamic changes may have resulted due to disordered vascular endothelial function, as reflected in alterations in L-Arg and ADMA levels.

• 한국산림과학회지
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• 제103권4호
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• pp.664-669
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• 2014

본 연구는 도시림에서의 경관감상과 산책이 인체의 생리적 안정에 미치는 영향을 규명하기 위해 수행되었다. 실험은 대전광역시에 위치한 한밭수목원에서 실시하였으며, 대조실험은 대전시청 앞에서 실시하였다. 20대 남자 대학생 24명(평균나이 $21.1{\pm}2.5$세)이 피험자로 참여하였고, 피험자를 세 그룹으로 나누어 수목원 내 소나무 숲, 수목원 내 연못, 도시 세 장소에 무작위 배치하였으며, 자리에 앉아 10분간 경관을 감상한 후 15분 동안 산책을 실시하였다. 측정지표로써 HRV, 혈압, 맥박수를 이용하여 생리적 변화를 측정하였다. 그 결과 도심 수목원 내에서 경관감상과 산책을 했을 때 도심과 비교하여 통계적으로 유의한 HF 성분의 증가와 수축기 혈압의 감소를 확인할 수 있었다. 본 연구를 통해 도심 수목원에서의 경관감상 또는 산책과 같은 활동이 도시민의 생리적 안정감을 향상시키는데 효과가 있음을 알 수 있었다.