• Journal of Korean Neurosurgical Society
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• v.66 no.6
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• pp.664-671
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• 2023

Objective : The optic nerve sheath diameter (ONSD)/eyeball transverse diameter (ETD) ratio is a more reliable marker of intracranial pressure than the ONSD alone. We aimed to investigate the predictive value of the ONSD/ETD ratio (OER) for neurological outcomes in patients with aneurysmal subarachnoid hemorrhage (aSAH). Methods : Adult patients with aSAH who visited the emergency department of a tertiary hospital connected to a South Korean university between January 2015 and December 2021 were included. Data on patient characteristics and brain computed tomography scan findings, including the ONSD and ETD, were collected using a predefined protocol. According to the neurological outcome at hospital discharge, the patients were divided into the unfavorable neurological outcome (UNO; cerebral performance category [CPC] score 3-5) and the favorable neurological outcome (FNO; CPC score 1-2) groups. The primary outcome was the association between the OER and neurological outcomes in patients with aSAH. Results : A total of 171 patients were included in the study, of whom 118 patients (69%) had UNO. Neither the ONSD (p=0.075) nor ETD (p=0.403) showed significant differences between the two groups. However, the OER was significantly higher in the UNO group in the univariate analysis (p=0.045). The area under the receiver operating characteristic curve of the OER for predicting UNO was 0.603 (p=0.031). There was no independent relationship between the OER and UNO in the multivariate logistic regression analysis (adjusted odds ratio, 0.010; p=0.576). Conclusion : The OER was significantly higher in patients with UNO than in those with FNO, and the OER was more reliable than the ONSD alone. However, the OER had limited utility in predicting UNO in patients with aSAH.

• Geomechanics and Engineering
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• v.36 no.4
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• pp.317-328
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• 2024

Adopting a rational engineering methodology for building structures on sandy-clay soil layers has become increasingly important since it is crucial when structures erected on them often face seismic and cyclic wave loads. Such loads can cause a reduction in the stiffness, strength, and stability of the structure, particularly under un-drained conditions. Hence, this study aims to investigate how the dynamic properties of sand-clay mixtures are affected by loading frequency and clay content. Cyclic triaxial tests were performed on a total of 36 samples, comprising pure sand with a relative density of 60% and sand with varying percentages of clay. The tests were conducted under confining pressures of 50 and 100 kPa, and the samples' dynamic behavior was analyzed at loading frequencies of 0.1, 1, and 4 Hz. The findings indicate that an increase in confining pressure leads to greater inter-particle interaction and a reduced void ratio, which results in an increase in the soil's shear modulus. An increase in the shear strength and confinement of the samples led to a decrease in energy dissipation and damping ratio. Changes in loading frequency showed that as the frequency increased, the damping ratio decreased, and the strength of the samples increased. Increasing the loading frequency not only reflects changes in frequency but also reduces the relative permeability and enhances the resistance of samples. An analysis of the dynamic properties of sand and sand-clay mixtures indicates that the introduction of clay to a sand sample reduces the shear modulus and permeability properties.

• The Journal of the Acoustical Society of Korea
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• v.29 no.8
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• pp.476-482
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• 2010

The ultrasonic transient fields and B-mode images of a point target which were simulated for a medical ultrasonic probe with a few defective piezo-elements were compared with those for a normal probe. The present study considered a 3.5 MHz linear array probe whose acoustic beam was formed by the 64 active elements of total 192 elements. The results showed that the maximum amplitude and -3 dB width of the acoustic fields by main-lobes decreased linearly as the defective element number increased from one to four. However, the depths of foci remained almost unchanged, and the pressure differences between main-lobes and side-lobes tended to decrease due to rise in pressures in side-lobes. Such changes in ultrasonic fields affected the B-mode images of point targets. So the artifacts were formed in the right and left side of the target, and the lateral spatial resolutions were decreased while the axial resolution was almost the same.

• Journal of the Korean Applied Science and Technology
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• v.40 no.4
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• pp.890-896
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• 2023

This study aims to examine the relationship between serum folic acid levels and metabolic syndrome. The analysis data were downloaded and used for the 7th 3rd (2018) data of the National Health and Nutrition Survey and in this study, 495 men, 706 women, and a total of 1,201 people were finally analyzed. The data analysis used Chi-square and t-test for the difference in serum folic acid according to general characteristics, Pearson correlation for the relationship between sub-factors of metabolic syndrome, and logistic regression analysis for serum folic acid levels and metabolic syndrome indicators. According to the results of this study, there was a significant negative correlation between serum folic acid levels and waist circumference (r=-0.113, p<0.01), triglyceride (r=-0.086, p<0.05), and HDL-cholesterol (r=0.086, p<0.05) showed a significant positive correlation. As a result of regression analysis, in the case of HDL-cholesterol, the group with normal serum folic acid levels was significantly higher than the group with low (p<0.05). Therefore, through this study, it is proposed to develop appropriate eating habits and health education programs to prevent metabolic syndrome.

• Nuclear Engineering and Technology
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• v.56 no.2
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• pp.575-600
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• 2024

During an earthquake on December 29th 2020, the Krško NPP automatically shutdown due to the trigger of the negative neutron flux rate signal on the power range nuclear instrumentation. From the time course of the detector signal, it can be concluded that the fluctuation in the detector signal may have been caused by the mechanical movement of the ex-core neutron detectors or the pressure vessel components rather than the actual change in reactor power. The objective of the analysis was to evaluate the sensitivity of the neutron flux at the ex-core detector position, if the detector is moved in the radial or axial direction. In addition, the effect of the core barrel movement and core inside the baffle movement in the radial direction were analysed. The analysis is complemented by the calculation of the thermal and total neutron flux gradient in radial, axial and azimuthal directions. The Monte Carlo particle transport code MCNP was used to study the changes in the response of the ex-core detector for the above-mentioned scenarios. Power and intermediate-range detectors were analysed separately, because they are designed differently, positioned at different locations, and have different response characteristics. It was found that the movement of the power range ex-core detector has a negligible effect on the value of the thermal neutron flux in the active part of the detector. However, the radial movement of the intermediate-range detector by 5 cm results in 7%-8% change in the thermal neutron flux in the active part of the intermediate-range detector. The analysis continued with an evaluation of the effects of moving the entire core barrel on the ex-core detector response. It was estimated that the 2 mm core barrel radial oscillation results in ~4% deviation in the power and intermediate-range detector signal. The movement of the reactor core inside baffle can contribute ~6% deviation in the ex-core neutron detector signal. The analysis showed that the mechanical movement of ex-core neutron detectors cannot explain the fluctuations in the ex-core detector signal. However, combined core barrel and reactor core inside baffle oscillations could be a probable reason for the observed fluctuations in the ex-core detector signal during an earthquake.

• Korean Journal of Radiology
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• v.20 no.6
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• pp.976-984
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• 2019

Objective: To establish diagnostic criteria for pulmonary arterial hypertension (PAH) in children by using parameters obtained through noninvasive cardiac computed tomography (CCT). Materials and Methods: We retrospectively measured parameters from CCT images of children from a single institution in a multiple stepwise process. A total of 208 children with mean age of 10.5 years (range: 4 days-18.9 years) were assessed. The variables were classified into three groups: the great arteries; the ventricular walls; and the bilateral ventricular cavities. The relationship between the parameters obtained from the CCT images and mean pulmonary arterial pressure (mPAP) was tested and adjusted by the children's body size. Reference curves for the pulmonary trunk diameter (PTD) and ratio of diameter of pulmonary trunk to ascending aorta (rPTAo) of children with CCT images of normal hearts, adjusted for height, were plotted. Threshold lines were established on the reference curves. Results: PTD and rPTAo on the CCT images were significantly positively correlated with mPAP (r > 0.85, p < 0.01). Height was the body size parameter most correlated with PTD (r = 0.91, p < 0.01) and rPTAo (r = -0.69, p < 0.01). On the basis of the threshold lines on the reference curves, PTD and rPTAo both showed 88.9% sensitivity for PAH diagnosis, with negative predictive values of 93.3% and 92.9%, respectively. Conclusion: PTD and rPTAo measured from CCT images were significantly correlated with mPAP in children. Reference curves and the formula of PTD and rPTAo adjusted for height could be practical for diagnosing PAH in children.

• Journal of Korean Physical Therapy Science
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• v.31 no.1
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• pp.1-15
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• 2024

Background: This study was conducted to apply active release techniques to male youth basketball players to help improve physical development and damage prevention and improve performance through improved balance and functional movement. Design: Randomized control trial. Methods: The subjects included 33 youth basketball players who were randomly assigned to the experimental group (n=17) and the control group (n=16). For the experimental group, the active release technique was applied to the hip muscles, calf muscles, posterior thigh muscles based on the distribution of injuries surveyed in youth basketball players in the Korean Basksetball League. The Y-balance test and the functional reach test (FRT) were used to assess balance and the Functional Movement Screen (FMS) was used to assess functional movement. Interventions were conducted twice a week for 4 weeks at 40 minutes per session. The experimental group was the active release technique group, and static stretching, a common exercise therapy technique, and self-myofascial release using a foam roller were applied for 20 minutes. The control group received general exercise therapy and placebo active release technique. The placebo active release technique applies pressure only. results:The experimental group showed a greater improvement in balance, as evidenced by the FRT, compared to the control group, which received general exercise treatment. However, there was no statistically significant difference in improvement between the 2 groups. In the case of the experimental group, the difference in the Y balance test before and after the intervention was larger than that of the control group, but there was no statistically significant difference. Significant improvement was found in functional movement, as evidence by the FMS, for the trunk stability test (p < 0.05), in-line lunge test (p < 0.05), rotational stability test (p < 0.05), total score (p < 0.05). Conclusion: In this study, the active release technique improved the balance and functional movement of young basketball players more than general exercise therapy. The application of the active release technique is therefore expected to assist in physical development, prevent damage, and improve the performance of youth basketball players.

• Journal of Chest Surgery
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• v.57 no.3
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• pp.255-262
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• 2024

Background: Sutureless aortic valves may enable shorter procedure times, which benefits patients with elevated surgical risk. We describe the outcomes of patients with aortic stenosis who underwent aortic valve replacement (AVR) using the sutureless Perceval aortic bioprosthesis. Methods: Data from a retrospective cohort were obtained from a clinical database. The study enrolled patients with symptomatic severe aortic stenosis who underwent surgical AVR with a sutureless bioprosthesis between August 2015 and December 2020. In total, 113 patients were included (mean age, 75.3±8.4 years; 57.5% women; median Society of Thoracic Surgeons score, 9.7%; mean follow-up period, 51.19±20.6 months). Of these patients, 41 were octogenarians (36.2%) and 3 were nonagenarians (2.6%). Transthoracic echocardiography was employed to assess changes in ejection fraction (EF), left ventricular mass index (LVMI), and mean pressure gradient (MPG). Results: The in-hospital mortality rate was 2.6%, and 13 patients developed new-onset atrial fibrillation. A permanent pacemaker was implanted in 3 patients (2.6%). The median intensive care unit stay was 1 day (interquartile range [IQR], 1-2 days), and the median hospital stay was 12 days (IQR, 9.5-15 days). The overall survival rate at 5 years was 95.9%. LVMI and MPG were reduced postoperatively, while EF increased over the follow-up period. No structural valve deterioration was observed, and no meaningful paravalvular leakage developed during follow-up. Conclusion: The use of a sutureless valve in the aortic position is safe and feasible, even for high-risk elderly patients requiring surgical AVR. LVMI and MPG decreased postoperatively, while EF increased over the follow-up period.

• Journal of Home Health Care Nursing
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• v.31 no.1
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• pp.44-55
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• 2024

Purpose: This is a retrospective secondary data analysis study based on real-world data to analyze the level of nursing care needs of patients in a comprehensive nursing care service ward, and identify factors influencing nursing needs. Methods: Study participants included patients admitted to two comprehensive nursing care service wards at a tertiary general hospital located in Gyeonggi-do, Korea. After obtaining permission from the health and medical information team of the target hospital, data were collected from their electronic medical records. Nursing care needs were measured using seven items on nursing activity and four items on daily living activities developed by the National Health Insurance Service (NHIS). The collected data were analyzed using the SPSS version 29.0 with frequency and percentage, mean and standard deviation, minimum and maximum values, t-test, ANOVA, Pearson's correlation coefficients, and multiple linear regression. Results: The level of nursing care needs of patients in comprehensive nursing care service wards was found to be higher for patients with pressure sores (β=.33), older patients (β=.26), patients who underwent procedures (β=.15), patients with present guardians (β=.15), and patients with more comorbidities (β=.10). The total explanatory power was 51.0%. Conclusion: It is necessary to accurately identify patients' nursing care needs and provide nursing care according to priority by considering the characteristics of patients in comprehensive nursing care service wards.

• The Journal of the Convergence on Culture Technology
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• v.10 no.3
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• pp.341-348
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• 2024

The purpose of this study is to analyze the structural relationship, direct and indirect effects between adolescents' peer attachment, self-resilience, academic stress, and smartphone addiction. The subject of this study used panel data of a total of 1280 middle school students who participated in the 14th study of the Children's Panel of the Korea Child Care Policy Institute. For data analysis, SPSS 24.0 and AMOS 24.0 programs were used. As a result of the study, children's peer attachment was positively correlated with ego resiliency, academic stress and negatively correlated with smartphone addiction. All pathways except peer attachment and smartphone addiction were found to have a direct influence, and adolescents' peer attachment had an indirect effect on smartphone addiction through ego resiliency and parental achievement pressure. In conclusion, in order to lower adolescents' smartphone addiction, practical interventions to improve ego resiliency and reduce academic stress through peer attachment are considered necessary.