• Journal of the Korean Society of Radiology
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• v.85 no.2
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• pp.308-326
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• 2024

A comprehensive evaluation of cardiac function includes information in relation to cardiac output and systemic venous return. The heart is composed of four chambers: two atria and two ventricles, each with its own unique mechanical function. These four cardiac chambers, their valves, and the pulmonary circulation system are inter-related as they preload or afterload on each other. Cardiac dysfunction is a failure of global cardiac function, resulting in typical clinical manifestations. To investigate the underlying cause of cardiac dysfunction, a step-by-step evaluation of cardiac blood flow tracks is necessary. In this context, imaging markers showing details of the cardiac structures have an important role in assessing cardiac function. An image-based evaluation allows for investigation of function in terms of individual cardiac components. Evaluation of cardiac function using cardiac CT has recently been validated. This review aimed to discuss cardiac CT-based imaging markers for comprehensive and detailed cardiac function assessment.

• Steel and Composite Structures
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• v.51 no.4
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• pp.351-361
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• 2024

Accurate measurement of K_IC values for gas pipeline steels is important for assessing pipe safety using failure assessment diagrams. As direct measurement of K_IC was impossible for the API X70 pipeline steel, multi-specimen fracture tests were conducted to measure J_IC using three-point bend geometry. The J values were calculated from load-displacement (F-δ) plots, and the associated crack extensions were measured from the fracture surface of test specimens. Valid data points were found for the constructed J-Δa plot resulting in J_IC=356kN/m. More data points were added analytically to the J-Δa plot to increase the number of data points without performing additional experiments for different J-Δa zones where test data was unavailable. Consequently, displacement (δ) and crack-growth (Δa) from multi-specimen tests (with small displacements) were used simultaneously, resulting in the variation of Δa-δ (crack growth law) and δ-Δa obtained for this steel. For new Δa values, corresponding δ values were first calculated from δ-Δa. Then, corresponding J values for the obtained δ values were calculated from the area under the F-δ record of a full-fractured specimen (with large displacement). Given Δa and J values for new data points, the developed J-Δa plot with extra data points yielded a satisfactory estimation of J_IC=345kN/m with only a -3.1% error. This is promising and showed that the developed technique could ease the estimation of J_IC significantly and reduce the time and cost of expensive extra fracture toughness tests.

• The Korean journal of internal medicine
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• v.39 no.3
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• pp.448-457
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• 2024

Background/Aims: Improved knowledge of local epidemiology and predicting risk factors of multidrug-resistant (MDR) bacteria are required to optimize the management of infections. This study examined local epidemiology and antibiotic resistance patterns of liver cirrhosis (LC) patients and evaluated the predictors of MDR bacteremia in Korea. Methods: This was a retrospective study including 140 LC patients diagnosed with bacteremia between January 2017 and December 2022. Local epidemiology and antibiotic resistance patterns and the determinants of MDR bacteremia were analyzed using logistic regression analysis. Results: The most frequently isolated bacteria, from the bloodstream, were Escherichia coli (n = 45, 31.7%) and Klebsiella spp. (n = 35, 24.6%). Thirty-four isolates (23.9%) were MDR, and extended-spectrum beta-lactamase E. coli (52.9%) and methicillin-resistant Staphylococcus aureus (17.6%) were the most commonly isolated MDR bacteria. When Enterococcus spp. were cultured, the majority were MDR (MDR 83.3% vs. 16.7%, p = 0.003), particularly vancomycin-susceptible Enterococcus faecium. Antibiotics administration within 30 days and/or nosocomial infection was a significant predictor of MDR bacteremia (OR: 3.40, 95% CI: 1.24-9.27, p = 0.02). MDR bacteremia was not predicted by sepsis predictors, such as positive systemic inflammatory response syndrome (SIRS) or quick Sequential Organ Failure Assessment (qSOFA). Conclusions: More than 70% of strains that can be treated with a third-generation cephalosporin have been cultured. In cirrhotic patients, antibiotic administration within 30 days and/or nosocomial infection are predictors of MDR bacteremia; therefore, empirical administration of broad-spectrum antibiotics should be considered when these risk factors are present.

• The Korean journal of internal medicine
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• v.39 no.3
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• pp.477-487
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• 2024

Background/Aims: Risk factors for progression to critical illness in hospital-acquired coronavirus disease 2019 (COVID-19) remain unknown. Here, we assessed the incidence and risk factors for progression to critical illness and determined their effects on clinical outcomes in patients with hospital-acquired COVID-19. Methods: This retrospective cohort study analyzed patients admitted to the tertiary hospital between January 2020 and June 2022 with confirmed hospital-acquired COVID-19. The primary outcome was the progression to critical illness of hospital-acquired COVID-19. Patients were stratified into high-, intermediate-, or low-risk groups by the number of risk factors for progression to critical illness. Results: In total, 204 patients were included and 37 (18.1%) progressed to critical illness. In the multivariable logistic analysis, patients with preexisting respiratory disease (OR, 3.90; 95% CI, 1.04-15.18), preexisting cardiovascular disease (OR, 3.49; 95% CI, 1.11-11.27), immunocompromised status (OR, 3.18; 95% CI, 1.11-9.16), higher sequential organ failure assessment (SOFA) score (OR, 1.56; 95% CI, 1.28-1.96), and higher clinical frailty scale (OR, 2.49; 95% CI, 1.62-4.13) showed significantly increased risk of progression to critical illness. As the risk of the groups increased, patients were significantly more likely to progress to critical illness and had higher 28-day mortality. Conclusions: Among patients with hospital-acquired COVID-19, preexisting respiratory disease, preexisting cardiovascular disease, immunocompromised status, and higher clinical frailty scale and SOFA scores at baseline were risk factors for progression to critical illness. Patients with these risk factors must be prioritized and appropriately isolated or treated in a timely manner, especially in pandemic settings.

• Journal of radiological science and technology
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• v.47 no.4
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• pp.287-294
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• 2024

Radiation oncology departments are at high risk for potential radiation safety incidents. This study aimed to identify risk factors for these incidents using the P-mSHEL (Patient, Management, Software, Hardware, Environment, and Liveware) model and to evaluate potential accident types through Failure Mode and Effects Analysis (FMEA). FMEA identified seven accident types with high Risk Priority Number (RPN). A total of 56 detailed risk factors were classified using the P-mSHEL model, and measures to prevent radiation safety incidents were implemented. The effect of these preventive measures on workers' safety perception was confirmed through two indicators (FMEA and safety perception). After implementing the preventive measures, the FMEA analysis showed that the highest reduction in RPN was for A-6 (radiation exposure while other patients/guardians are present) with a reduction rate of 33.3%, followed by B-3 (radiation exposure while staff are present) with a reduction rate of 33.3%. Overall safety perception significantly improved after the preventive measures (4.17±0.35) compared to before (2.76±0.33) (p<0.05), with notable increases in both employee safety culture (3.93±0.51) and patient safety culture (3.73±0.62) (p<0.05). This study identified risk factors in radiation oncology departments. Continuous management, maintenance, and fostering a strong safety culture are crucial for preventing incidents. Regular problem identification and collaboration with relevant departments are essential for maintaining safety standards.

• Clinical and Experimental Pediatrics
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• v.52 no.10
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• pp.1153-1160
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• 2009

Purpose:To evaluate the risk factors for mortality and prognostic factors in pediatric hemato-oncology patients admitted to the pediatric intensive care unit (PICU). Methods:We retrospectively reviewed the medical records of pediatric hemato-oncology patients admitted at the PICU of the Asan Medical Center between September 2005 and July 2008. Patients admitted at the PICU for perioperative or terminal care were excluded. Results:Total 88 patients were analyzed. Overall ICU mortality rate was 34.1%. Mean age at PICU admission was $7.0{\pm}5.7$ years and mean duration of PICU stay was $18.1{\pm}22.2$ days. Hematologic diseases contributed to 77.3% of all the primary diagnoses, and the primary cause of admission was respiratory failure (39.8%). The factors related to increased mortality were C-reactive protein level (P<0.01), ventilation or dialysis requirement (P<0.01), and hematopoietic stem cell transplantation (P<0.05). In all, 3 scoring systems were investigated [Number of Organ System Failures (OSF number), the Pediatric Risk of Mortality III (PRISM III) score, and the Sequential Organ Failure Assessment (SOFA) score]; higher score correlated with worse outcome (P<0.01). The Oncological Pediatric Risk of Mortality (O-PRISM) scores of the 21 patients who had received hematopoietic stem cell transplantation were higher among the non-survivors, but not statistically significant (P=0.203). Conclusion:The PRISM III and SOFA scores obtained within 24 hours of PICU admission were found to be useful as early mortality predictors. The highest OSF number during the PICU stay was closely related to poor outcome.

• Journal of Korean Tunnelling and Underground Space Association
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• v.24 no.6
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• pp.451-464
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• 2022

The high-level nuclear waste repository is a deep geological disposal system exposed to complex environmental conditions such as high temperature, radiation, and ground-water due to handling spent nuclear fuel. Continuous exposure can lead to cracking and deterioration of the structure over time. On the other hand, the high-level nuclear waste repository requires an ultra-long life expectancy. Thus long-term structural health monitoring is essential. Various sensors such as an accelerometer, earth pressure gauge, and displacement meter can be used to monitor the health of a structure, and a piezoelectric sensor is generally used. Therefore, it is necessary to develop a highly durable sensor based on the durability assessment of the piezoelectric sensor. This study designed an accelerated life test for durability assessment and life prediction of the piezoelectric sensor. Based on the literature review, the number of accelerated stress levels for a single stress factor, and the number of samples for each level were selected. The failure mode and mechanism of the piezoelectric sensor that can occur in the environmental conditions of the high-level waste repository were analyzed. In addition, two methods were proposed to investigate the maximum harsh condition for the temperature stress factor. The reliable operating limit of the piezoelectric sensor was derived, and a reasonable accelerated stress level was set for the accelerated life test. The suggested methods contain economical and practical ideas and can be widely used in designing accelerated life tests of piezoelectric sensors.

• Journal of Educational Research in Mathematics
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• v.20 no.3
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• pp.413-444
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• 2010

The purpose of the present study is to develop an instrument of mathematical learning motivation and causal attribution for students and to analyze the results of the instrument. Based on the literature review, mathematical learning motivation is the cumulative effects of self-assessment and self-regulation in mathematical learning and achievement experience. Three factors of mathematical learning motivation is identified as self-regulatory efficacy, task difficulty and mathematical anxiety with 17 self-regulatory efficacy items, 9 task difficulty items and 9 mathematical anxiety items. Three factors of causal attribution for success is identified as ability/effort, luck, and other person with 6 ability/effort items, 4 luck items and 3 other person items. Also, four factors of causal attribution for failure is identified as ability, effort, luck, and other person with 3 ability items, 7 effort items, 3 luck items and 4 other person items. The instrument of mathematical learning motivation and causal attribution for success and failure was administered to 919 middle school students from eight different middle middle schools in Seoul, Gyeonggi-Do, Busan, jeolla-Do area. The correlation of three factors of mathematical learning motivation was calculated. As a result, a positive correlation between self-regulatory efficacy and task difficulty was appeared but mathematical anxiety has a negative correlation with self-regulatory efficacy and task difficulty. This study also examined the differences about mathematical learning motivation's sub-factors shown by three groups of mathematics achievement level. Students of higher achievement level showed that the degree of self-regulatory efficacy and task difficulty was higher than that of lower level group. Students of lowest achievement level showed significantly higher mathematical anxiety degree than that of middle and high group. Students that have higher degree of self-regulatory efficacy and task difficulty preference were attributed into ability/effort cause toward success of mathematics achievement. Also, Male students preferred more difficult task and higher degree of self-regulatory efficacy in mathematics learning than female students. On the contrary, Female students showed higher mathematical anxiety level than male students.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.10 no.5
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• pp.1-13
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• 2015

The purpose of this research is to do exploratory analysis on the relationships between demographic characteristics of entrepreneurial candidates and their developmental level of entrepreneurial traits as well as the choice of business field. We analyzed gender, age, and educational level of the entrepreneurial candidates and their developmental level of entrepreneurial traits such as achievement tendencies, degree of awareness, planning skills, sincerity, interpersonal relationship, and problem-solving skills. Industry fields were classified into 4 types: restaurants, retail, services, internet business. Descriptive statistical analyses, logistic regressions, and variance analyses were performed about the sample data gathered from 1,441 persons since the year 2002 to 2014. Males and highly educated above university preferred service industry than restaurant, retail, and internet business. Females preferred internet business, retail, and restaurants than service industry field. The young persons under 20 showed higher probability to choose internet business. The college level and high school graduates preferred retail and restaurants than service industry. The developmental level of entrepreneurial traits were higher in male and highly educated. By this study, we could find the divide between groups with high and low probabilities of failure: restaurants and retail field showed higher failure probability than service industry in the business fields of self-employed. Furthermore, we could identify that entrepreneurial traits also had been developed differently depending on the groups. It is necessary to refrain from entering into the fields with high failure probabilities as well as to provide supporting policies to build the systems and environment to reduce the cases to begin new business without special knowledges and know-hows. The competency development training should be provided in the early stage of start-ups considering their entrepreneurial traits and aptitudes. Not only the assessment of the entrepreneurial traits but also professional counseling from initial stage are necessary.

• Journal of Nutrition and Health
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• v.43 no.3
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• pp.224-232
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• 2010

The prevalence of heart failure (HF) is increasing globally and growing evidence has shown that dietary factors play an important role in preventing and improving prognosis of HF. However, little data on nutrient intake in Korean HF patients which are available to develop dietary guidelines for HF. The aims of this study were to estimate nutrient intake in 78 HF patients and evaluate whether the estimated nutrient intake is appropriate compared to dietary reference intake for Koreans. Data are presented as the ratio of actual intake and estimated average requirement (EAR) for each nutrient. The result showed that the average nutrient intakes including total energy and protein met EAR in total patients. However, the deficiencies in mineral and vitamin intakes were found. Moreover, the proportion of subjects with lower intake than EAR was substantial. The results showed that the proportion of male HF patients with inferior intakes to EAR in calcium, potassium (compared to adequate intake: AI), folate and vitamin $B_{12}$ were 38%, 79%, 38%, and 65%, respectively. Also, the proportion of female HF patients with inferior intakes to EAR in calcium, potassium (compared to AI), folate and vitamin $B_{12}$ were 35%, 88%, 38% and 40%, respectively. In particular, the elderly with HF ($\geq$ 70 yrs, n = 28) showed more serious deficiencies in calcium, potassium (compared to AI), folate and vitamin $B_{12}$. In summary, the intakes of potassium, calcium, folate, and vitamin B12 were not sufficient to meet EAR in HF patients. Furthermore, the proportions of subjects with lower intake than EAR in these nutrients were substantial, raising the possibility that these micronutrients may be involved in the pathogenesis of HF. Practical dietary guideline for HF patients is needed to improve prognosis of HF.