• Interdisciplinary Bio Central
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• v.1 no.2
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• pp.8.1-8.6
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• 2009

Introduction: It is a challenge to design a protein score function which stabilizes the native structures of many proteins simultaneously. The coarse-grained description of proteins to construct the pairwise-contact score function usually ignores the backbone directionality of protein structures. We propose a new two-body score function which stabilizes all native states of 1,006 proteins simultaneously. This two-body score function differs from the usual pairwise-contact functions in that it considers two adjacent amino acids at two ends of each peptide bond with the backbone directionality from the N-terminal to the C-terminal. The score is a corresponding propensity for a directional alignment of two adjacent amino acids with their local environments. Results and Discussion: We show that the construction of a directional adjacency-score function was achieved using 1,006 training proteins with the sequence homology less than 30%, which include all representatives of different protein classes. After parameterizing the local environments of amino acids into 9 categories depending on three secondary structures and three kinds of hydrophobicity of amino acids, the 32,400 adjacency-scores of amino acids could be determined by the perceptron learning and the protein threading. These could stabilize simultaneously all native folds of 1,006 training proteins. When these parameters are tested on the new distinct 382 proteins with the sequence homology less than 90%, 371 (97.1%) proteins could recognize their native folds. We also showed using these parameters that the retro sequence of the SH3 domain, the B domain of Staphylococcal protein A, and the B1 domain of Streptococcal protein G could not be stabilized to fold, which agrees with the experimental evidence.

• Tuberculosis and Respiratory Diseases
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• v.83 no.4
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• pp.268-275
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• 2020

Background: It is not evident that the attributable risk of smoking on mortality in Korea has decreased. We investigated the impact of smoking on all-cause mortality and estimated the attributable risk of smoking in Korean adults. Methods: Those aged ≥20 years with smoking history in the Korean National Health and Nutrition Examination Surveys (KNHANES) 2007-2015 were enrolled. We categorized the participants into three groups as follows: never smoker, <20 pack-years (PY) smokers, and ≥20 PY smokers. We applied inverse probability weighting using propensity scores to control various confounders between the groups. All-cause mortality risks were compared between the groups using the Kaplan-Meier log-rank test. The effects of smoking-attributable risks (ARs) on mortality were also calculated. Results: A total of 50,458 participants were included. Among them, 19,334 (38.3%) were smokers and 31,124 (61.7%) were never smokers. Those with a smoking history of 20 PY or more (≥20 PY smokers), those with a smoking history of less than 20 PY (<20 PY smokers), and never smokers were 18.1%, 20.2%, and 61.7%, respectively, of the study population. Smokers had a higher risk of all-cause mortality compared to never smokers (log-rank test p<0.01). The ARs of smoking were 21.8% (95% confidence interval [CI], 5.7%-37.9%) and 9.0% (95% CI, 6.1%-12.0%) in males and females, respectively. ARs decreased from 24.2% to 19.5% in males and from 9.5% to 4.1% in females between 2007-2010 and 2011-2015. Conclusion: Our study using KNHANES IV-VI data demonstrated that smoking increased the risk of all-cause mortality in a dose-response manner and the ARs of smoking on mortality were 21.8% in males and 9.0% in females during 2007-2015. This suggests that the ARs of smoking on mortality have decreased since around 2010.

• Tuberculosis and Respiratory Diseases
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• v.83 no.4
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• pp.303-311
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• 2020

Background: If the duration of mechanical ventilation (MV) is related with the intensive care unit (ICU) readmission must be clarified. The purpose of this study was to elucidate if prolonged MV duration increases ICU readmission rate. Methods: The present observational cohort study analyzed national healthcare claims data from 2006 to 2015. Critically ill patients who received MV in the ICU were classified into five groups according to the MV duration: MV for <7 days, 7-13 days, 14-20 days, 21-27 days, and ≥28 days. The rate and risk of the ICU readmission were estimated according to the MV duration using the unadjusted and adjusted analyses. Results: We found that 12,929 patients had at least one episode of MV in the ICU. There was a significant linear relationship between the MV duration and the ICU readmission (R²=0.85, p=0.025). The total readmission rate was significantly higher as the MV duration is prolonged (MV for <7 days, 13.9%; for 7-13 days, 16.7%; for 14-20 days, 19.4%; for 21-27 days, 20.4%; for ≥28 days, 35.7%; p<0.001). The analyses adjusted by covariables and weighted with the multinomial propensity scores showed similar results. In the adjusted regression analysis with a Cox proportional hazards model, the MV duration was significantly related to the ICU readmission (hazard ratio, 1.058 [95% confidence interval, 1.047-1.069], p<0.001). Conclusion: The rate of readmission to the ICU was significantly higher in patients who received longer durations of the MV in the ICU. In the clinical setting, closer observation of patients discharged from the ICU after prolonged periods of MV is required.

• Journal of Korean Medicine Rehabilitation
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• v.29 no.4
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• pp.89-100
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• 2019

Objectives We are going to analyze patient's medical and Korean medicine use trends after lumbar surgery, and examine the percentage of use of Korean medicine after surgery and its relevance to the medical care outcome after lumbar surgery. Methods Using 3% patients' sample data of the Health Insurance Review and Assessment Service, two groups were compared the treatment progress of the Korean Medicine treatment group and the untreated group after lumbar surgery by hierarchical logistic regression analysis. After hierarchical logistic regression analysis(including propensity scores), two groups were compared after lumbar surgery, the Korean Medicine treatment group within 50days and untreated group within 50days. Results Lumbar surgery was performed in 2750 patients in 2015. It was 3.72 that the risk(odds ratio) of finished treatment of patients treated without Korean Medicine, compared to patients with Korean Medicine. It was 0.12 that the risk of continuing treatment(odds ratio) of patients treated with Korean Medicine within 50 days, compared to patients treatment more than 50 days. Conclusions The ratio of Korean Medicine treatment after lumbar surgery was 14.8%. The group that did not have Korean Medicine showed a higher possibility of treatment termination than the group who did not. Among the groups treated with Korean Medicine, the early treatment group was more likely to end treatment than the late treatment group. Considering various situations in the medical environment, further studies such as prospective studies and long-term data analysis are considered to be necessary.

• Journal of Obesity & Metabolic Syndrome
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• v.27 no.4
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• pp.238-247
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• 2018

Background: We aimed to estimate the proportion of patients with diabetes who achieved target glycemic control, to estimate diabetes-related costs attributable to poor control, and to identify factors associated with them in the United Arab Emirates. Methods: This retrospective cohort study used administrative claims data handled by Abu Dhabi Health Authority (January 2010 to June 2012) to determine glycemic control and diabetes-related treatment costs. A total of 4,058 patients were matched using propensity scores to eliminate selection bias between patients with glycosylated hemoglobin (HbA1c) <7% and HbA1c ${\geq}7%$. Diabetes-related costs attributable to poor control were estimated using a recycled prediction method. Factors associated with glycemic control were investigated using logistic regression and factors associated with these costs were identified using a generalized linear model. Results: During the 1-year follow-up period, 46.6% of the patients achieved HbA1c <7%. Older age, female sex, better insurance coverage, non-use of insulin in the index diagnosis month, and non-use of antidiabetic medications during the follow-up period were significantly associated with improved glycemic control. The mean diabetes-related annual costs were $2,282 and $2,667 for patients with and without glycemic control, respectively, and the cost attributable to poor glycemic control was $172 (95% confidence interval [CI], $164-180). The diabetes-related costs were lower with mean HbA1c levels <7% (cost ratio, 0.94; 95% CI, 0.88-0.99). The costs were significantly higher in patients aged ${\geq}65$ years than those aged ${\leq}44$ years (cost ratio, 1.45; 95% CI, 1.25-1.70). Conclusion: More than 50% of patients with diabetes had poorly controlled HbA1c. Poor glycemic control may increase diabetes-related costs.

• The Journal of the Korea Contents Association
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• v.19 no.3
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• pp.171-182
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• 2019

As online shopping malls continue to grow in popularity, various chances of consumption are provided to customers. Customers decide the purchase by exploiting information provided by shopping malls such as the reviews of actual purchasing users, the detailed information of items, and so on. It is required to provide objective and reliable information because customers have to decide on their own whether the massive information is credible. In this paper, we propose a personalized recommendation method considering an item confidence to recommend reliable items. The proposed method determines user preferences based on various behaviors for personalized recommendation. We also propose an user preference measurement that considers time weights to apply the latest propensity to consume. Finally, we predict the preference score of items that have not been used or purchased before, and we recommend items that have highest scores in terms of both the predicted preference score and the item confidence score.

• Journal of Trauma and Injury
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• v.32 no.1
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• pp.40-46
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• 2019

Purpose: We perform an analysis of infection risk factors for fracture patients and confirm that the risk factors reported in previous studies increase the risk of actual infection among fractured patients. In addition, injury severity score (ISS) which is used as an evaluation tool for morbidity of trauma patients, confirms whether there is a relationship with infection after orthopedic fracture surgery. Methods: We retrospectively reviewed 1,818 patients who underwent fixation surgery at orthopedic trauma team, focused trauma center from January 1, 2015 to December 31, 2017. Thirty-five patients were infected after fracture surgery. We analyzed age, sex, open fracture criteria based on Gustilo-Aderson classification 3b, anatomical location (upper extremity or lower extremity) of fracture, diabetes, smoking, ISS. Results: Of 1,818 patients, 35 (1.9%) were diagnosed with postoperative infection. Of the 35 infected patients, nine (25.7%) were female and five (14.0%) were upper extremity fractures. Three (8.6%) were diagnosed with diabetes and eight (22.8%) were smokers. Thirteen (37.1%) had ISS less than nine points and six (17.1%) had ISS 15 points or more. Of 1,818 patients, 80 had open fractures. Surgical site infection were diagnosed in 12 (15.0%) of 80. And nine of 12 were checked with Gustilo-Aderson classification 3b or more. Linear logistic regression analysis was performed using statistical analysis program Stata 15 (Stata Corporation, College Station, TX, USA). In addition, independent variables were logistic regression analyzed individually after Propensity scores matching. In all statistical analyzes, only open fracture was identified as a risk factor. Conclusions: The risk factors for infection in fracture patients were found to be significantly influenced by open fracture rather than the underlying disease or anatomical feature of the patient. In the case of ISS, it is considered that there is a limitation. It is necessary to develop a new scoring system that can appropriately approach the morbidity of fracture trauma patients.

• Hip & pelvis
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• v.30 no.4
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• pp.219-225
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• 2018

Purpose: Ischiofemoral impingement (IFI)-primarily diagnosed by magnetic resonance imaging (MRI)-is an easily overlooked disease due to its low incidence. The purpose of this study was to evaluate the usefulness of false profile view as a screening test for IFI. Materials and Methods: Fifty-eight patients diagnosed with IFI between June 2013 and July 2017 were enrolled in this retrospective study. A control group (n=58) with matching propensity scores (age, gender, and body mass index) were also included. Ischiofemoral space (IFS) was measured as the shortest distance between the lateral cortex of the ischium and the medial cortex of lesser trochanter in weight bearing hip anteroposterior (AP) view and false profile view. MRI was used to measure IFS and quadratus femoris space (QFS). The receiver operating characteristics (ROC), area under the ROC curve (AUC) and cutoff point of the IFS were measured by false profile images, and the correlation between the IFS and QFS was analyzed using the MRI scans. Results: In the false profile view and hip AP view, patients with IFI had significantly decreased IFS (P<0.01). In the false profile view, ROC AUC (0.967) was higher than in the hip AP view (0.841). Cutoff value for differential diagnosis of IFI in the false profile view was 10.3 mm (sensitivity, 88.2%; specificity, 88.4%). IFS correlated with IFS (r=0.744) QFS (0.740) in MRI and IFS (0.621) in hip AP view (P<0.01). Conclusion: IFS on false profile view can be used as a screening tool for potential IFI.

• Tuberculosis and Respiratory Diseases
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• v.84 no.2
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• pp.115-124
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• 2021

Background: This study aimed to determine the parameters for worsening oxygenation in non-severe coronavirus disease 2019 (COVID-19) pneumonia. Methods: This retrospective cohort study included cases of confirmed COVID-19 pneumonia in a public hospital in South Korea. The worsening oxygenation group was defined as that with SpO₂ ≤94% or received oxygen or mechanical ventilation (MV) throughout the clinical course versus the non-worsening oxygenation group that did not experience any respiratory event. Parameters were compared, and the extent of viral pneumonia from an initial chest computed tomography (CT) was calculated using artificial intelligence (AI) and measured visually by a radiologist. Results: We included 136 patients, with 32 (23.5%) patients in the worsening oxygenation group; of whom, two needed MV and one died. Initial vital signs and duration of symptoms showed no difference between the two groups; however, univariate logistic regression analysis revealed that a variety of parameters on admission were associated with an increased risk of a desaturation event. A subset of patients was studied to eliminate potential bias, that ferritin ≥280 ㎍/L (p=0.029), lactate dehydrogenase ≥240 U/L (p=0.029), pneumonia volume (p=0.021), and extent (p=0.030) by AI, and visual severity scores (p=0.042) were the predictive parameters for worsening oxygenation in a sex-, age-, and comorbid illness-matched case-control study using propensity score (n=52). Conclusion: Our study suggests that initial CT evaluated by AI or visual severity scoring as well as serum markers of inflammation on admission are significantly associated with worsening oxygenation in this COVID-19 pneumonia cohort.

• Journal of Korean Neurosurgical Society
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• v.66 no.1
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• pp.63-71
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• 2023

Objective : Traumatic brain injury (TBI) is one of the most common injuries in patients with multiple trauma, and it associates with high post-traumatic mortality and morbidity. A trauma center was established to provide optimal treatment for patients with severe trauma. This study aimed to compare the treatment outcomes of patients with severe TBI between non-trauma and trauma centers based on data from the Korean Neuro-Trauma Data Bank System (KNTDBS). Methods : From January 2018 to June 2021, 1122 patients were enrolled in the KNTDBS study. Among them, 253 patients from non-traumatic centers and 253 from trauma centers were matched using propensity score analysis. We evaluated baseline characteristics, the time required from injury to hospital arrival, surgery-related factors, neuromonitoring, and outcomes. Results : The time from injury to hospital arrival was shorter in the non-trauma centers (110.2 vs. 176.1 minutes, p=0.012). The operation time was shorter in the trauma centers (156.7 vs. 128.1 minutes, p=0.003). Neuromonitoring was performed in nine patients (3.6%) in the non-trauma centers and 67 patients (26.5%) in the trauma centers (p<0.001). Mortality rates were lower in trauma centers than in non-trauma centers (58.5% vs. 47.0%, p=0.014). The average Glasgow coma scale (GCS) at discharge was higher in the trauma centers (4.3 vs. 5.7, p=0.011). For the Glasgow outcome scale-extended (GOSE) at discharge, the favorable outcome (GOSE 5-8) was 17.4% in the non-trauma centers and 27.3% in the trauma centers (p=0.014). Conclusion : This study showed lower mortality rates, higher GCS scores at discharge, and higher rates of favorable outcomes in trauma centers than in non-trauma centers. The regional trauma medical system seems to have a positive impact in treating patients with severe TBI.