Objective: This study examined whether related experts within the same organ know the standardized viscosity system of fluids and can manufacture solutions consistently. Methods: The subjects of this study were 22 rehabilitation ward nurses, 21 non-rehabilitation ward nurses, and 19 occupational therapists. The additional thickeners, manufacturing time and order, viscosity appropriateness, and solution homogeneity were measured for IDDSI level 4, 3, and 2 solutions manufactured using xanthan gum-based food thickeners. Results: The viscosity appropriateness in the three groups in stages IDDSI levels 4 and 3, but there was a significant difference among the three groups in stage IDDSI level 2. The factors affecting viscosity appropriateness were group and homogeneity of solution. The rehabilitation nurse group produced thicker solutions than the IDDSI standard compared to the other group. The homogeneity of the solution showed significant differences among the three groups in IDDSI levels 4, 3, and 2. The factors affecting homogeneity included the manufacturing order and job group, which often resulted in a clumping phenomenon when water was added first. Compared to the groups of therapists, the clumping phenomenon was significantly higher in the nurse (IDDSI level 3) and non-rehabilitation nurse groups (IDDSI level 4, 3) than the occupational therapists group. Conclusion This study showed that awareness and education about the liquid stage are necessary for medical personnel involved in hydration for patients with dysphagia and that consistent application using a standardized food thickener protocol at an institution is necessary.

Background: Cardiac resynchronization therapy (CRT) is an effective treatment option for patients with heart failure (HF) and left ventricular (LV) dyssynchrony. However, the problem of some patients not responding to CRT remains unresolved. This study aimed to propose a novel in silico method for CRT simulation. Methods: Three-dimensional heart geometry was constructed from computed tomography images. The finite ele‑ ment method was used to elucidate the electric wave propagation in the heart. The electric excitation and mechani‑ cal contraction were coupled with vascular hemodynamics by the lumped parameter model. The model parameters for three-dimensional (3D) heart and vascular mechanics were estimated by matching computed variables with measured physiological parameters. CRT effects were simulated in a patient with HF and left bundle branch block (LBBB). LV end-diastolic (LVEDV) and end-systolic volumes (LVESV), LV ejection fraction (LVEF), and CRT responsiveness measured from the in silico simulation model were compared with those from clinical observation. A CRT responder was defined as absolute increase in LVEF ≥ 5% or relative increase in LVEF ≥ 15%. Results: A 68-year-old female with nonischemic HF and LBBB was retrospectively included. The in silico CRT simu‑ lation modeling revealed that changes in LVEDV, LVESV, and LVEF by CRT were from 174 to 173 mL, 116 to 104 mL, and 33 to 40%, respectively. Absolute and relative ΔLVEF were 7% and 18%, respectively, signifying a CRT responder.In clinical observation, echocardiography showed that changes in LVEDV, LVESV, and LVEF by CRT were from 162 to 119 mL, 114 to 69 mL, and 29 to 42%, respectively. Absolute and relative ΔLVESV were 13% and 31%, respectively, also signifying a CRT responder. CRT responsiveness from the in silico CRT simulation model was concordant with that in the clinical observation. Conclusion This in silico CRT simulation method is a feasible technique to screen for CRT non-responders in patients with HF and LBBB.

Melanogenesis is the production of melanin from tyrosine by a series of enzyme-catalyzed reactions, in which tyrosinase and DOPA oxidase play key roles. The melanin content in the skin determines skin pigmentation. Abnormalities in skin pigmentation lead to various skin pigmentation disorders. Recent research has shown that the expression of EMP2 is much lower in melanoma than in normal melanocytes, but its role in melanogenesis has not yet been elucidated. Therefore, we investigated the role of EMP2 in the melanogenesis of MNT1 human melanoma cells. We examined TRP-1, TRP-2, and TYR expression levels during melanogenesis in MNT1 melanoma cells by gene silencing of EMP2. Western blot and RT-PCR results confirmed that the expression levels of TYR and TRP-2 were decreased when EMP2 expression was knocked down by EMP2 siRNA in MNT1 cells, and these changes were reversed when EMP2 was overexpressed. We verified the EMP2 gene was knocked out of the cell line (EMP2 CRISPR/Cas9) by using a CRISPR/Cas9 system and found that the expression levels of TRP-2 and TYR were significantly lower in the EMP2 CRISPR/Cas9 cell lines. Loss of EMP2 also reduced migration and invasion of MNT1 melanoma cells. In addition, the melanosome transfer from the melanocytes to keratinocytes in the EMP2 KO cells cocultured with keratinocytes was reduced compared to the cells in the control coculture group. In conclusion, these results suggest that EMP2 is involved in melanogenesis via the regulation of TRP-2 expression.

Purpose: Pediatricians have a significant responsibility to educate mothers about the importance of breastfeeding. However, there have been minimal efforts in the courses of resident training in Korea. The purpose of this study is to evaluate the change in knowledge and attitude before and after a 4-week breastfeeding educational intervention among multicenter residents. Methods: Prospective interventional educational research was designed for residents at eight training hospitals in Korea. Institutional reviews were obtained in each hospital. The education curriculum consisted of 14 courses regarding breastfeeding theory and practice. These materials were used to teach pediatric residents for 4 weeks. Knowledge-based tests were administered before the course, and re-tests were administered after the course using different test items of similar levels. Test scores and survey responses were compared before and after the intervention. Results: A total of 73 residents (1st year 20, 2nd year 23, 3rd year 16, and 4th year residents 14) from eight training hospitals completed the intervention. Their average age was 30.3±2.9 years, 17 (23.3%) were male, 22 (30.1%) were married, and eight had more than one child of their own. The mean pre-test score was 61.8±13.4 and the mean post-test score was 78.3±7.5 (P<0.001). The inter-grade difference in the score was significant in the pre-test (P=0.005), but not significant in the post-test (P=0.155). There were more responses of obtaining confidence after the intervention (P<0.001). Conclusion In our study, pediatric residents showed improvement in their knowledge and confidence level after 4 weeks of the breastfeeding curriculum. This will provide a basis for future policymaking in the training of pediatric residents regarding breastfeeding in Korea.

Background: This study used machine learning and population data for testing the associations of preterm birth with gastroesophageal reflux disease (GERD) and periodontitis. Methods: Retrospective cohort data came from Korea National Health Insurance Service claims data for all women who aged 25–40 years and gave births for the first time as singleton pregnancy during 2015–2017 (405,586 women). The dependent variable was preterm birth during 2015–2017 and the independent variables were GERD (coded as no vs. yes) for each of the years 2002–2014, periodontitis (coded as no vs. yes) for each of the years 2002–2014, age (year) in 2014, socioeconomic status in 2014 measured by an insurance fee, and region (city) (coded as no vs. yes) in 2014. Random forest variable importance was adopted for finding main predictors of preterm birth and testing its associations with GERD and periodontitis. Results: Based on random forest variable importance, main predictors of preterm birth during 2015–2017 were socioeconomic status in 2014, age in 2014, GERD for the years 2012, 2014, 2010, 2013, 2007 and 2009, region (city) in 2014 and GERD for the year 2006. The importance rankings of periodontitis were relatively low. Conclusion Preterm birth has a stronger association with GERD than with periodontitis. For the prevention of preterm birth, preventive measures for GERD would be essential together with the improvement of socioeconomic status for pregnant women. Especially, it would be vital to promote active counseling for general GERD symptoms (neglected by pregnant women).

Angiography ; Bias (Epidemiology) ; Constriction, Pathologic ; Coronary Angiography ; Fractional Flow Reserve, Myocardial ; Humans ; Ischemia ; Patient-Specific Modeling ; Sensitivity and Specificity

Background: Periodontitis is reported to be associated with preterm birth (spontaneous preterm labor and birth). Gastroesophageal reflux disease (GERD) is common during pregnancy and is expected to be related to periodontitis. However, little research has been done on the association among preterm birth, GERD and periodontitis. This study uses popular machine learning methods for analyzing preterm birth, GERD and periodontitis. Methods: Data came from Anam Hospital in Seoul, Korea, with 731 obstetric patients during January 5, 1995 - August 28, 2018. Six machine learning methods were applied and compared for the prediction of preterm birth. Variable importance, the effect of a variable on model performance, was used for identifying major determinants of preterm birth. Results: In terms of accuracy, the random forest (0.8681) was similar with logistic regression (0.8736). Based on variable importance from the random forest, major determinants of preterm birth are delivery and pregestational body mass indexes (BMI) (0.1426 and 0.1215), age (0.1211), parity (0.0868), predelivery systolic and diastolic blood pressure (0.0809 and 0.0763), twin (0.0476), education (0.0332) as well as infant sex (0.0331), prior preterm birth (0.0290), progesterone medication history (0.0279), upper gastrointestinal tract symptom (0.0274), GERD (0.0242), Helicobacter pylori (0.0151), region (0.0139), calcium-channel-blocker medication history (0.0135) and gestational diabetes mellitus (0.0130). Periodontitis ranked 22nd (0.0084). Conclusion GERD is more important than periodontitis for predicting and preventing preterm birth. For preventing preterm birth, preventive measures for hypertension, GERD and diabetes mellitus would be needed alongside the promotion of effective BMI management and appropriate progesterone and calcium-channel-blocker medications.

Background: This paper proposes a novel method for automatically identifying sleep apnea (SA) severity based on deep learning from a short-term normal electrocardiography (ECG) signal. Methods: A convolutional neural network (CNN) was used as an identification model and implemented using a one-dimensional convolutional, pooling, and fully connected layer.An optimal architecture is incorporated into the CNN model for the precise identification of SA severity. A total of 144 subjects were studied. The nocturnal single-lead ECG signal was collected, and the short-term normal ECG was extracted from them. The short-term normal ECG was segmented for a duration of 30 seconds and divided into two datasets for training and evaluation. The training set consists of 82,952 segments (66,360 training set, 16,592 validation set) from 117 subjects, while the test set has 20,738 segments from 27 subjects. Results: F1-score of 98.0% was obtained from the test set. Mild and moderate SA can be identified with an accuracy of 99.0%. Conclusion The results showed the possibility of automatically identifying SA severity based on a short-term normal ECG signal.