• Korean Journal of Remote Sensing
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• v.37 no.6_1
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• pp.1739-1756
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• 2021

Atmospheric nitrogen dioxide (NO₂) is mainly caused by anthropogenic emissions. It contributes to the formation of secondary pollutants and ozone through chemical reactions, and adversely affects human health. Although ground stations to monitor NO₂ concentrations in real time are operated in Korea, they have a limitation that it is difficult to analyze the spatial distribution of NO₂ concentrations, especially over the areas with no stations. Therefore, this study conducted a comparative experiment of spatial interpolation of NO₂ concentrations based on two linear-regression methods(i.e., multi linear regression (MLR), and regression kriging (RK)), and two machine learning approaches (i.e., random forest (RF), and support vector regression (SVR)) for the year of 2020. Four approaches were compared using leave-one-out-cross validation (LOOCV). The daily LOOCV results showed that MLR, RK, and SVR produced the average daily index of agreement (IOA) of 0.57, which was higher than that of RF (0.50). The average daily normalized root mean square error of RK was 0.9483%, which was slightly lower than those of the other models. MLR, RK and SVR showed similar seasonal distribution patterns, and the dynamic range of the resultant NO₂ concentrations from these three models was similar while that from RF was relatively small. The multivariate linear regression approaches are expected to be a promising method for spatial interpolation of ground-level NO₂ concentrations and other parameters in urban areas.

• The Korean Journal of Medicine
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• v.93 no.6
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• pp.538-547
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• 2018

Background/Aims: The impact of left ventricular (LV) diastolic function and filling pressure on clinical outcomes in young patients with acute myocardial infarction (AMI) has been poorly studied. Therefore, the aim of this study was to investigate the impact of LV diastolic function and LV filling pressure on major adverse cardiac events (MACEs) in young patients with AMI. Methods: A total of 200 young patients (males < 45 year, females < 55 year) with AMI were divided into two groups according to the diastolic function; normal (n = 46, $39.5{\pm}5.3$ years) versus abnormal (n = 154, $43.5{\pm}5.1$ years). Results: Despite regional wall motion abnormalities, normal LV diastolic function was not uncommon in young AMI patients (23.0%). During the 40 months of clinical follow-up, MACEs developed in 26 patients (13.0%); 14 re-percutaneous coronary intervention (7.0%), 8 recurrent MI (4.0%), and 4 deaths (2.0%). MACEs did not differ between the normal and abnormal diastolic function group (13.6% vs. 10.9%, p = 0.810), but MACEs were significantly higher in the high LV filling pressure group than the normal LV filling pressure group (36.8% vs. 10.5%, p < 0.001). On multivariate analysis, high LV filling pressure was an independent predictor of MACEs (hazard ratio 3.022, 95% confidence interval 1.200-7.612, p = 0.019). Conclusions: This study suggested that measurement of the LV filling pressure (E/e' ratio) would be useful in the risk stratification of young patients with AMI. However, it would be necessary to monitor this category of patient more carefully.

• Journal of Nutrition and Health
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• v.52 no.2
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• pp.227-241
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• 2019

Purpose: This study examined the relationship between caffeine intake and metabolic syndrome in Korean adults using the 2013 ~ 2016 Korea National Health and Nutrition Examination Survey data (KNHANES). Methods: The caffeine database (DB) developed by Food and Drug Safety Assessment Agency in 2014 was used to estimate the caffeine consumption. The food and beverage consumption of the 24 hr recall data of 2013 ~ 2016 KNHANES were matched to items in the caffeine DB and the daily caffeine intakes of the individuals were calculated. The sample was limited to non-pregnant healthy adults aged 19 years and older, who were not taking any medication for disease treatment. Results: The average daily caffeine intake was 41.97 mg, and the daily intake of caffeine of 97% of the participants was from coffee, teas, soft drinks, and other beverages. Multivariate analysis showed that the caffeine intake did not affect metabolic syndrome, hypertension, low HDL-cholesterol, and abdominal obesity. Diabetes and hypertriglyceridemia, however, were 0.76 (95% CI: 0.63 ~ 0.93), and 0.87 (95% CI: 0.77 ~ 0.98) in third quintile (Q3), and 0.66 (95% CI: 0.53 ~ 0.82) and 0.83 (95% CI: 0.73 ~ 0.94) in fourth quintile (Q4) compared to Q1, respectively. Therefore, caffeine intake of 3.66 ~ 45.81 mg per day is related to a lower risk of diabetes and hypertriglyceridemia. Conclusion: The study showed that adequate caffeine intake (approximately 45 mg) was associated with a lower prevalence of diabetes and hypertriglyceridemia. Therefore, it can be used as a guideline for the adequate level of caffeine intake for maintaining health.

• Sleep Medicine and Psychophysiology
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• v.26 no.1
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• pp.33-43
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• 2019

Objectives: Bipolar disorder is characterized by repetitive relapses that result in psychosocial dysfunctions. The functioning of bipolar disorder patients is related to the severity of symptoms, quality of sleep, drug compliance, and social support. The purpose of this study was to investigate the association between sociodemographic and clinical factors and functional status in bipolar disorder patients. Methods: A total of 52 bipolar disorder patients participated in the study. The following scales were utilized: Korean version of personal and social performance scale (K-PSP), Korean version of Hamilton rating scale for depression (K-HDRS), Korean version of young mania rating scale (K-YMRS), Korean version of pittsburgh sleep quality index (PSQI-K), Korean version of drug attitude inventory (K-DAI), mood disorders insight scale (MDIS), and multidimensional scale of perceived social support (MSPSS). Results: The K-PSP score showed a negative relationship with K-HDRS score (r = -0.387, p = 0.005), but not with K-YMRS score (r = -0.205, p = 0.145). The K-PSP score showed a negative relationship with global PSQI-K score (r = -0.378, p = 0.005) and overall sleep quality (r = -0.353, p = 0.010). The K-PSP scores were positively associated with the KDAI score (r = 0.409, p = 0.003) and MSPSS score (r = 0.334, p = 0.015). The predictive factors for K-PSP were overall sleep quality and social support from family. Conclusion: Our study showed that depressive symptoms were related to overall function in bipolar disorder. Also, our study suggested that improving sleep quality is important in maintaining functional status. Appropriate social support and positive perception toward the drug may lead to the higher level of functioning. This study is meaningful in that the functional status of bipolar disorder patients is analyzed in a multivariate manner in relation to various variables in psychosocial aspects.

• The Korean Journal of Gastroenterology
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• v.72 no.6
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• pp.286-294
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• 2018

Background/Aims: The predictive factors of functional dyspepsia (FD) remain controversial. Therefore, we sought to investigate symptom responses in FD patients after Helicobacter pylori (H. pylori) eradication and used predictive factor analysis to identify significant factors of FD resolution at one-year after commencing eradication therapy. Methods: This prospective, multi-center clinical trial was performed on 65 FD patients that met Rome III criteria and had H. pylori infection. Symptom responses and factors that predicted poor response were determined by analysis one year after commencing H. pylori eradication therapy. Results: A total of 63 patients completed the one-year follow-up. When an eradication success group (n=60) and an eradication failure group (n=3) were compared with respect to FD response rate at one year, results were as follows; complete response 73.3% and 0.0%, satisfactory response 1.7% and 0.0%, partial response 10.0% and 33.3%, and refractory response 15.0% and 66.7%, respectively (p=0.013). Univariate analysis showed persistent H. pylori infection (p=0.021), female gender (p=0.025), and medication for FD during the study period (p=0.013) were associated with poor FD response at one year. However, age, smoking, alcohol consumption, and underlying disease were not found to affect response. Finally, multivariate analysis showed that female gender (OR, 4.70; 95% CI, 1.17-18.88) was the sole independent risk factor of poor FD response at one year after commencing H. pylori eradication therapy. Conclusions: Female gender was found to predict poor response in FD patients despite H. pylori eradication. Furthermore, successful H. pylori eradication appears to be associated with FD improvement, but the number of non-eradicated patients was too small to conclude.

• The Korean journal of helicobacter and upper gastrointestinal research
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• v.18 no.4
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• pp.247-257
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• 2018

Background/Aims: The aim of this study was to analyze the trend of the prevalences of atrophic gastritis (AG) and intestinal metaplasia (IM) from 2011 to 2016~2017 in Korea. And, the risk factors of AG and IM were compared between 2011 and 2016~2017. Materials and Methods: A total of 4,023 subjects in 2011 and 2,506 subjects in 2016~2017 were enrolled. AG and IM were diagnosed on the basis of endoscopic findings. Multivariate analysis was performed for risk factors of AG and IM. Seventeen factors were analyzed. Results: The seroprevalence of Helicobacter pylori decreased from 2011 (59.8%; 2,407/4,023) to 2016~2017 (51.6%; 1,293/2,506; P<0.001). The prevalence of AG decreased from 2011 to 2016~2017 (P=0.018), but that of IM increased (P<0.001). The risk factors of AG in 2011 were male sex, old age, H. pylori immuoglobulin G (IgG) positivity, family history of gastric cancer (GC), and high-salt diet. For IM in 2011, the risk factors were male sex, old age, H. pylori IgG positivity, and family history of GC. Risk factors of AG in 2016~2017 were old age, H. pylori IgG positivity, and country of residence. For IM in 2016~2017, the risk factors were male sex, old age, family history of GC, high fasting glucose level (${\geq}126mg/dL$), H. pylori IgG positivity, and low income level. Conclusions: The difference in prevalence trends of AG and IM between 2016~2017 and 2011 could be the result of the different risk factors of AG and IM, such as decreased prevalence of H. pylori infection.

• Korean Journal of Psychosomatic Medicine
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• v.26 no.2
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• pp.94-101
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• 2018

Objectives : The purpose of this study is to investigate the change pattern and the leading factors of delirium in the palliative ward from 2 weeks before to the end of life. Methods : From October 2015 to August 2017, a retrospective chart review was conducted on the final 180 patients of 207 patients with terminal cancer patients at the Inha University Hospital. Clinical records were collected during palliative care hospitalization. Patients were diagnosed with three subtypes of delirium through the Richmond Agitation Sedation Scale and the Nursing Delirium Screening Scale, which were evaluated daily. Results : The prevalence of delirium 13 days before death was 46%, of which 18.3% were hyperactive subtypes, 13.8% were hypoactive subtypes, and mixed subtypes were 13.8%. And hyperactive delirium gradually decreased with the approach to the end of the day, and the mixed subtype gradually increased until 4 days before the end of life. Of the patients, the day before death, 86.9% were diagnosed with delirium. In multivariate analysis, hematologic malignancy was associated with a lower rate of delirium at the end of life than gastrointestinal cancer. Overweight was associated with hyperactive, mixed, and hypoactive delirium. Conclusions : Most palliative care patients experienced delirium at the end of life. Overweight was considered as a protective factor that reduced the all subtypes of delirium at the end of life. Further prospective studies are needed to reveal the prevalence of terminal delirium, and their risk factors.

• The Korean Journal of Nuclear Medicine Technology
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• v.25 no.2
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• pp.48-54
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• 2021

Purpose In ¹⁸F-FDG PET/CT, the absorption of ¹⁸F-FDG due to the activation of Brown Adipose Tissue (BAT) greatly interferes with the discrimination of lymph node malignant metastasis. Warming the patient's body temperature before and after injection of ¹⁸F-FDG to prevent FDG absorption by BAT is a safe and non-pharmacological approach. The purpose of this study was to identify and select patients with a high potential for BAT activation in advance, and to investigate whether BAT can inhibit FDG absorption when the body temperature is raised for a short time by directly applying heat to the target patient. Materials and Methods Among the patients who underwent ¹⁸F-FDG PET/CT at the National Cancer Center from January 2020 to December 2020, 825 female patients (415 in the thermal group, 410 in the non-thermal group) under 50 years old were included. The thermal group was administered heat for 10 minutes before injection of ¹⁸F-FDG. For statistical analysis, the Z test comparing the ratios between the two groups was used, and logistic regression analysis was performed to correct for important variables (BMI, outdoor temperature, blood sugar) according to the results of the previous retrospective study. Results Among 825 patients, 19 patients with BAT activated (Thermal group: 5(1.2%), Non-thermal group: 14(3.41%)) accounted for 2.3% of the total. As a result of performing the Z test to compare the ratios between the two groups, the activation of BAT in the thermal group was significantly decreased (P=0.034). In the univariate logistic regression analysis, the activation of BAT was also decreased in the thermal group (OR: 0.34, P<0.05). In the multivariate results, BAT activation increased in patients younger than 45 years old (OR: 4.46, P<0.05) and outdoor temperature less than 13.2 degrees (OR: 9.97, P<0.05). BAT activation tended to decrease in the thermal group, but there was no significant difference (OR: 0.37, P=0.066). Conclusion We confirmed that the activation of BAT tends to decrease by 62.5% in the group subjected to the thermal method, and it will be of great help in preventing FDG absorption of BAT more effectively in the future.

• Journal of Gastric Cancer
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• v.22 no.1
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• pp.67-77
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• 2022

Purpose: Tegafur/gimeracil/oteracil (S-1) and capecitabine plus oxaliplatin (CAPOX) are standard adjuvant chemotherapies (ACs) administered after gastrectomy to patients with stage II or III gastric cancer. However, the efficacy of AC in elderly patients remains unclear. The objective of this retrospective multicenter cohort study was to compare the efficacies of S-1 and CAPOX AC in patients aged ≥70 years. Materials and Methods: Nine hundred eighty-three patients who were treated with AC using S-1 (768 patients) or CAPOX (215 patients) were enrolled in this study. Each patient underwent AC after curative gastrectomy for stage II or III gastric cancer at one of 27 hospitals in the Republic of Korea between January 2012 and December 2013. Relapse-free survival (RFS) and overall survival (OS) were analyzed according to AC regimen and age group. Results: Of the 983 patients, 254 (25.8%) were elderly. This group had a similar RFS (P=0.099) but significantly poorer OS (p=0.003) compared with the non-elderly group. Subgroup analysis of the non-elderly group revealed no AC-associated differences in survival. Subgroup analysis of the elderly group revealed significantly better survival in the S-1 group than in the CAPOX group (RFS, P<0.001; OS, P<0.001). Multivariate analysis revealed that the CAPOX regimen was an independent poor prognostic factor for RFS (hazard ratio [HR], 1.891; 95% confidence interval [CI], 1.072-3.333; P=0.028) and OS (HR, 2.970; 95% CI, 1.550-5.692; P=0.001). Conclusions: This multicenter observational cohort study found significant differences in RFS and OS between S-1 and CAPOX AC among patients with gastric cancer aged ≥70 years.

• Journal of the Korean Orthopaedic Association
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• v.56 no.5
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• pp.413-418
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• 2021

Purpose: To investigate the effect of facet tropism on the degeneration of facet joint and intervertebral disc in the cervical spine. Materials and Methods: From January 2017 to December 2018, cervical tropism of 100 patients at the C5/6 level was analyzed retrospectively. In computed tomography (CT), the orientation and tropism of the facet joint with respect to the sagittal, coronal, and horizontal planes were measured. Regression of the facet joint in magnetic resonance imaging (MRI) and CT was assessed using a grading system. Intervertebral disc degeneration was assessed and divided into five grades on MRI. For the left and right asymmetry, a difference between two facet angles of less than 7° was classified as the control group, more than 7° was classified as the tropism group. Results: The mean age of the patients was 55.44±12.3 years (31-81 years) in the tropism group and 55.66±10.7 years (32-76 years) in the control group. In the tropism group, 32 were male and 18 were female. In the control group, 24 were male and 26 were female. Facet joint degeneration was identified in 24 patients (48.0%) in the tropism group and 14 patients (28.0%) in the control group, showing a significant difference. Intervertebral disc degeneration was identified in 29 patients (58.0%) in the tropism group and 17 patients (34.0%) in the control group, showing a significant difference. Multivariate revealed, tropism to be a factor that affected the facet joint and intervertebral disc degeneration. Conclusion: Facet joint and intervertebral disc degeneration occurred significantly in the tropism group, and tropism is a factor affecting the degeneration of facet joint and intervertebral disc in the C5/6 level.