• Geomechanics and Engineering
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• v.36 no.5
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• pp.465-474
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• 2024

Uniaxial compressive strength (UCS) is a critical geomechanical parameter that plays a significant role in the evaluation of rocks. The practice of indirectly estimating said characteristics is widespread due to the challenges associated with obtaining high-quality core samples. The primary aim of this study is to investigate the feasibility of utilizing the gene expression programming (GEP) technique for the purpose of forecasting the UCS for various rock categories, including Schist, Granite, Claystone, Travertine, Sandstone, Slate, Limestone, Marl, and Dolomite, which were sourced from a wide range of quarry sites. The present study utilized a total of 170 datasets, comprising Schmidt hammer (SH), porosity (n), point load index (Is(50)), and P-wave velocity (Vp), as the effective parameters in the model to determine their impact on the UCS. The UCS parameter was computed through the utilization of the GEP model, resulting in the generation of an equation. Subsequently, the efficacy of the GEP model and the resultant equation were assessed using various statistical evaluation metrics to determine their predictive capabilities. The outcomes indicate the prospective capacity of the GEP model and the resultant equation in forecasting the unconfined compressive strength (UCS). The significance of this study lies in its ability to enable geotechnical engineers to make estimations of the UCS of rocks, without the requirement of conducting expensive and time-consuming experimental tests. In particular, a user-friendly program was developed based on the GEP model to enable rapid and very accurate calculation of rock's UCS, doing away with the necessity for costly and time-consuming laboratory experiments.

• Clinical and Experimental Pediatrics
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• v.49 no.7
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• pp.769-776
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• 2006

Purpose : Pulse wave velocity(PWV) and ankle brachial index(ABI) are not only noninvasive methods used to assess arterial stiffness in adults, but also useful, simple ways to estimate the severity of hypertension, end stage renal disease and atherosclerosis in adults. But there are few studies on PWV and ABI in adolescents and children. In this study, hypertensive adolescents were compared to normal individuals to find out the usefulness of PWV as the index of progress in the disease. Methods : 413 teenagers were divided into three groups. The first group consisted of adolescents that only had hypertension(Group 1 : 23 teenagers). The second group consisted of the adolescents who had hypertension with obesity(Group 2 : 17 teenagers), and the last group was the normal subjects(Group 3 : 328 teenagers). Weight, height and body mass index were measured. Simultaneous measurements of systolic, diastolic and average blood pressure were obtained from the four extremities. PWV, ABI, ejection time and preejection period were also measured. Results : Right brachial-ankle PWV was significantly higher in both group 1 and group 2 compared with group 3, and significantly higher in group 2 compared with group 1. Likewise, left brachial-ankle PWV also showed significantly higher values in both group 1 and group 2 compared with group 3, and also higher values in group 2 compared with group 1. Positive correlations were found between the systolic, diastolic, average blood pressure and PWV. There were also positive correlations between the blood pressure and weight, body mass index. Conclusion : Higher PWV was demonstrated in adolescents with essential hypertension compared to normal subjects. Follow-up study is needed to evaluate the progress.

• Clinical and Experimental Pediatrics
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• v.52 no.10
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• pp.1109-1118
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• 2009

Purpose : Metabolic syndrome (MS), characterized by obesity and insulin resistance, elicits risk factors such as hyperlipidemia, hypertension, and glucose intolerance with additive effects on atherosclerosis, leading to cardiovascular diseases. The purposes of this study were to evaluate the prevalence of MS among overweight and obese adolescents and to investigate the impact of obesity on the cardiovascular system. Methods : In all, 684 adolescents were included in the study. Blood pressure, body mass index (BMI), fasting blood glucose, total cholesterol, triglyceride, low-density-lipoprotein (LDL)-cholesterol, high-density-lipoprotein (HDL)-cholesterol, aspartate aminotransferase (AST), alanine aminotransferase (ALT), and high-sensitive C-reactive protein (hs-CRP) were measured in the patients with a BMI of >85 percentile. Brachial-ankle pulse wave velocity (BaPWV) and ankle brachial index were measured using Vascular Profiler (VP)-1000. Results : MS was confirmed in 19.5% of the overweight and obese adolescents and 50.8% of the obese adolescents. The systolic and diastolic blood pressure, height, weight, fat mass, %fat, BMI, obesity index, and waist circumference were higher in the overweight and obese adolescents with MS. Moreover, the triglyceride, AST, ALT, and hs-CRP levels were higher, whereas HDL-cholesterol level was significantly lower in this group. The overweight and obese adolescents with MS showed shorter diastolic and systolic times, higher heart rate and BaPWV, and longer E-wave deceleration time by echocardiography. Conclusion : Overweight and obese adolescents showed characteristic MS features such as hypertension and hyperlipidemia. Thus, obese adolescents predisposed to MS should be provided early treatment for obesity.

• Clinical and Experimental Pediatrics
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• v.50 no.6
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• pp.549-555
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• 2007

Purpose : Pulse wave velocity (PWV) and ankle brachial index (ABI) are simple, non-invasive methods to assess arterial stiffness. These parameters are also known to be closely related to cardiovascular risk factors and diseases. The purposes of this study were to measure blood pressure, PWV, ABI in healthy Korean adolescents, set up their normal values and assess their correlations. Methods : Three hundred ninety two healthy adolescents (213 boys and 179 girls) underwent measurement of brachial ankle pulse wave velocity (baPWV), ABI, body mass index(BMI) and blood pressure from four extremities. Linear regression analysis was performed to reveal the correlations between PWV, ABI and independent variables. Results : Blood pressure and PWV were significantly higher in all extremities in males compared to females. Blood pressure of both brachial and ankle showed positive correlation with body weight, height, and BMI, whereas ABI showed no correlation with any of these indices. Conclusion : Blood pressure increases as body weight, height and BMI increases. PWV shows positive correlation with blood pressure. It will be helpful to predict the risks of cardiovascular diseases in adolescents.

• Journal of Nutrition and Health
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• v.55 no.4
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• pp.506-520
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• 2022

Purpose: Physical activity (PA) has a beneficial effect on the prevention of arteriosclerosis in healthy adults. The purpose of this study was to analyze the relationship between PA measured using an accelerometer and arterial stiffness in healthy Korean adults. Methods: This study involved 87 subjects (36.8% women) aged 20-64 years. PA was evaluated using an accelerometer (wGT3X-BT, ActiGraph, Florida, USA) for 7 days. Based on the results of the accelerometer measurement, subjects were classified into active and inactive groups according to the World Health Organization (WHO) PA guidelines. The brachial-ankle pulse wave velocity (baPWV) and ankle-brachial index (ABI) to assess arterial stiffness were measured by a non-invasive vascular screening device (VP-1000 Plus, Omron). Results: The average age of the study subjects was 47.7 ± 11.3 years and the WHO PA guideline achievement rate was 29.9%. There was no significant difference in arterial stiffness (baPWV and ABI) between the active and inactive groups. In females, the time spent in light PA were positively correlated with ABI (r = 0.396; p < 0.05) and the number of sedentary bouts over 50 minutes was inversely correlated with ABI (r = -0.402; p < 0.05). However, there was no significant correlation between PA and arterial stiffness in males. Conclusions: The results of this study suggest that light PA and sedentary behavior have a positive correlation with arterial stiffness in females.

• Journal of Veterinary Clinics
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• v.31 no.5
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• pp.367-370
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• 2014

The study was to observe hemodynamic alterations of cardiac function to design a model of canine mitral valve insufficiency (MVI) based on chordae tendinae rupture (CTR). Ten healthy beagles with normal heart function were used in this study. To measure hemodynamics, the patient monitor was equipped for invasive blood pressure and a Swan-Ganz catheter. Hemodynamic alterations were checked promptly during CTR procedures. MVI model was made by transection of the chordae tendinae with small arthroscopy hook knife through $5^{th}$ intercostal open chest. Color Doppler at the level of the mitral valve showed high-velocity regurgitant flow immediately after CTR at intraoperative echocardiography. In hemodynamic measurements, pulmonary capillary wedge pressure (PCWP) was significantly increased, while mean arterial pressure (MAP), venous pressure (VP), pulmonary arterial pressure (PAP), cardiac output (CO) and cardiac index (CI) were significantly decreased after CTR. It was known that the left atrium was overloaded by regurgitant volume from the left ventricle. In conclusion, the MVI model induced by CTR technique in this study should be used as suitable one for the effective research of canine mitral valve disease. Further study should be needed to measure the chronic alternation of mitral valve in the model.

• Clinical and Experimental Pediatrics
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• v.50 no.11
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• pp.1078-1084
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• 2007

Purpose : The prevalence of childhood obesity has doubled over the last 30 years. Obesity-associated sequelae in the vasculature begins in the early stages of life. The purpose of this study was to investigate how pulse wave velocity (PWV) and ankle brachial index (ABI) change with height, weight and body mass index (BMI) in obese adolescents. Methods : Seventy-nine obese adolescents (group 1: $85th{\leq}BMI<95th$ percentile, n=40; group 2 ($BMI{\geq}95th$ percentile, n=39) were included. The control group(group 3) included 99 healthy adolescents. Brachial- ankle (ba) PWV and ABI were estimated with blood pressure from four extremities. Heart rate (HR), and pre-ejection period/ejection time (PEP/ET) were also estimated. BMI was calculated from individual height and weight. Linear regression analysis was performed to evaluate the correlations between BMI and PWV. Results : Blood pressure and baPWV were significantly higher in group 2, compared to either group 1 or group 3. However, there was no significant difference in ABI, HR and PEP/ET between the groups. PWV showed linear correlation with both BMI and body weight. Conclusion : Obesity was associated with higher arterial stiffness in adolescents, which was demonstrated by an increase in PWV. There was no significant correlation between obesity and ABI.

• Clinical and Experimental Pediatrics
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• v.52 no.1
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• pp.36-43
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• 2009

urpose : The renin-angiotensin system (RAS) has been demonstrated to play a major role in regulating blood pressure. Therefore, components of the RAS are likely candidate genes that may predispose an individual to essential hypertension and cardiovascular complications. Among them, the M235T polymorphism of the angiotensinogen gene has been speculated to be associated with elevated circulating angiotensinogen concentrations and essential hypertension. This study aimed to analyze the angiotensinogen M235T polymorphism in hypertensive adolescents and investigate its relationship with cardiovascular risks. Methods : Forty Korean hypertensive adolescents (aged 16-17, systolic $BP{\geq}140 mmHg$ and/or diastolic $BP{\geq}90 mmHg$) and fifty seven normal adolescents were included. Obesity index (OI), body mass index (BMI) were calculated. BP was measured by oscillometric methods in resting state. Polymerase chain reaction (PCR) technique was performed on DNA from the hypertensives subjects to analyze the M235T polymorphism. Serum homocysteine, insulin, renin, aldosterone and angiotensin converting enzyme (ACE) were tested according to each genotype. The carotid intima-media thickness (IMT) and carotid artery diameter, Pulse wave velocity (PWV) and ankle-brachial index (ABI) were measured according to each genotype. Results : Genotype frequencies of T/T, M/T and M/M were 62.5%, 35.0%, 2.5%, respectively in hypertensive adolescents. The results were not significantly different compared to control group. Serum insulin, renin levels, BMI and OI were significantly higher in thoses with the M/M genotype as compared to those with the T/T of M/T genotype. Conclusion : This study showed that the M235T polymorphism was not associated with essential hypertension or any cardiovascular risks. Further clinical research is required to ascertain the relationship between this polymorphism and cardiovascular complications in Korean hypertensive adolescents.