• 생물정신의학
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• 제30권1호
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• pp.24-30
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• 2023

Objectives Alzheimer's disease (AD) is the most common form of dementia in older adults, damaging the brain and resulting in impaired memory, thinking, and behavior. The identification of differentially expressed genes and related pathways among affected brain regions can provide more information on the mechanisms of AD. The aim of our study was to identify differentially expressed genes associated with AD and combined biomarkers among them to improve AD risk prediction accuracy. Methods Machine learning methods were used to compare the performance of the identified combined biomarkers. In this study, three publicly available gene expression datasets from the hippocampal brain region were used. Results We detected 31 significant common genes from two different microarray datasets using the limma package. Some of them belonged to 11 biological pathways. Combined biomarkers were identified in two microarray datasets and were evaluated in a different dataset. The performance of the predictive models using the combined biomarkers was superior to those of models using a single gene. When two genes were combined, the most predictive gene set in the evaluation dataset was ATR and PRKCB when linear discriminant analysis was applied. Conclusions Combined biomarkers showed good performance in predicting the risk of AD. The constructed predictive nomogram using combined biomarkers could easily be used by clinicians to identify high-risk individuals so that more efficient trials could be designed to reduce the incidence of AD.

• Journal of Preventive Medicine and Public Health
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• 제51권3호
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• pp.154-162
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• 2018

Objectives: Early retirement occurs when one's job satisfaction suffers due to employment mismatch resulting from factors such as inadequate compensation. Medical doctors report high levels of job stress and burnout relative to other professionals. These levels are highest among emergency physicians (EPs), and despite general improvements in their working conditions, early retirement continues to become more common in this population. The purpose of this study was to identify the factors influencing EPs intention to retire early and to develop a probability equation for its prediction. Methods: A secondary analysis of data from the 2015 Korean Society of Emergency Physicians Survey was performed. The variables potentially influencing early retirement were organized into personal characteristics, extrinsic factors, and intrinsic factors. Logistic regression analysis was performed to identify risk factors and to develop a probability equation; these findings were then arranged in a nomogram. Results: Of the 377 survey respondents included in the analysis, 48.0% intended to retire early. Risk factors for early retirement included level of satisfaction with the specialty and its outlook, slanderous reviews, emergency room safety, health status, workload intensity, age, and hospital type. Intrinsic factors (i.e., slanderous reviews and satisfaction with the specialty and its outlook) had a stronger influence on early retirement than did extrinsic factors. Conclusions: To promote career longevity among EPs, it is vital to improve emergency room safety and workload intensity, to enhance medical professionalism through a stronger vision of emergency medicine, and to strengthen the patient-doctor relationship.

• 한국암반공학회:학술대회논문집
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• 한국암반공학회 2000년도 암반공학문제의 수치해석(Numerical Analysis in Rock Engineering Problems)
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• pp.155-161
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• 2000

터널공학에 있어서 지보시스템에 가해지는 최종 하중을 제어하기 위한 지보의 거동에 관한 많은 연구가실시되었다. 기술적으로 타당한 설계와 안전율이 확보된 경제적인 시공을 위해서는 해석의 신뢰성이 확보되어야 한다. 또한 굴착과 보강의 일련의 시공과정에 대한 역학적인 이해가 필요하며 암반-지보 반응거동에 대한 규명이 이루어 져야 한다. 암반과 지보의 거동에 관한 대부분의 연구는 단순화한 가정에 의한 이론적 해석이 주를 이루고 있다. 또한 터널 주위의 암반 조건에 따른 명확한 기준이 없어 터널 설계시 어려움이 많다. 본 연구에서는 유한차분해석 프로그램인 FLAC을 이용하여 암반조건에 따른 해석을 실시하여 암반-지보 반응곡선을 구하였다. 실제 시공과 유사한 조건을 부여하기 위해 암반등급과 측압계수를 달리하여 해석을 실시하였다. 그 결과 암반조건에 다른 암반-지보 반응곡선의 nomogram을 도출하였으며, 이는 설계 초기에 지보압 및 터널의 허용변위에 대한 효율적인 예측을 실시하는데 있어 유용할 것이다.

• 터널과지하공간
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• 제10권3호
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• pp.403-409
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• 2000

터널공학에 있어서 지보시스템에 가해지는 최종 하중을 제어하기 위한 지보의 거동에 관한 많은 연구가 실시되었다. 기술적으로 타당한 설계와 안전율이 확보된 경제적인 시공을 위해서는 해석의 신뢰성이 확보되어야 한다. 또한 굴착과 보강의 일련의 시공과정에 대한 역학적인 이해가 필요하며 암반-지보 반응거동에 대한 규명이 이루어져야 한다. 암반과 지보의 거동에 관한 대부분의 연구는 단순화한 가정에 의한 이론적 해석이 주를 이루고 있다. 또한 터널 주위의 암반 조건에 따른 명확한 기준이 없어 터널 설계 시 어려움이 많다 본 연구에서는 유한차분해석 프로그램인 FLAC을 이용하여 암반조건에 따른 해석을 실시하여 암반-지보 반응곡선을 구하였다. 실제 시공과 유사한 조건을 부여하기 위해 암반등급과 측압계수를 달리하여 해석을 실시하였다. 그 결과 암반조건에 다른 암반-지보 반응곡선의 nomogram을 도출하였으며, 이는 설계 초기에 지보압 및 터널의 허용변위에 대한 효율적인 예측을 실시하는데 있어 유용할 것이다.

• Journal of Gastric Cancer
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• 제19권4호
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• pp.393-407
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• 2019

Purpose: To identify the potential therapeutic role of postoperative radiotherapy (RT) in patients with locally advanced (stage II and stage III) gastric signet ring cell carcinoma (SRC). Materials and methods: Patients with locally advanced gastric SRC from the Surveillance, Epidemiology, and End Results program database between 2004 and 2012 were included in our study. Univariate and multivariate Cox proportional models were performed, and survival curves were generated to evaluate the prognostic effect of postoperative RT and surgery alone on SRC patients. Propensity score matching (PSM) was used to avoid selection bias among the study cohorts. Results: We found that patients with postoperative RT had better probability of survival compared with those who did not receive RT (overall survival [OS], P<0.001; cancer-specific survival [CSS], P<0.001). After PSM, analysis of both overall and CSS showed that patients who underwent postoperative RT had better prognosis than those receiving surgery alone in the matched cohort (OS, P=0.00079; CSS, P=0.0036). Multivariate Cox proportional model indicated that postoperative RT had better effect on prognosis compared with surgery alone with respect to both overall (hazard ratio [HR], 0.716; 95% confidence interval [95% CI], 0.590-0.87; P=0.001) and CSS (HR, 0.713; 95% CI, 0.570-0.890; P=0.003). Conclusions: Postoperative RT had better prognosis compared with surgery alone for both overall and CSS for patients with locally advanced gastric SRC.

• 터널과지하공간
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• 제24권1호
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• pp.97-109
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• 2014

본 연구는 현재 제품화 되고 있는 뇌관의 지연시차인 20, 25 ms의 지연시차와 기폭위치(정기폭, 중간기폭, 역기폭)에 따라 발파에 의한 지반진동의 전파특성을 파악하기 위해 공간격, 저항선, 천공장 그리고 장약량을 달리하여 총 4회의 시험발파를 실시하여 지반진동 예측식을 도출하였다. 도출된 평균 지반진동 예측식을 통해 지연시차와 기폭위치에 따른 최대입자속도의 노모그램 분석을 통해 진동특성을 규명하였고, 국토교통부의 "도로공사 노천발파 설계 시공 지침 및 요령"에 제시된 표준발파공법의 공법별 경계 기준 장약량인 0.5, 1.6, 5, 15 kg을 적용하여 진동중가율을 비교분석하였다. 그리하여 장약량에 따라 진동제어에 유리한 발파방법을 제안하여 발파설계의 인자로 사용할 수 있도록 하였다.

• 대한임상독성학회지
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• 제21권2호
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• pp.128-134
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• 2023

Purpose: The Prescott nomogram has been utilized to forecast hepatotoxicity from acute acetaminophen poisoning. In developing countries, emergency medical centers lack the resources to report acetaminophen concentrations; thus, the commencement and cessation of treatment are based on the reported dose. This study investigated risk factors that can predict acetaminophen detection after 15 hours for safe treatment termination. Methods: Data were collected from an urban emergency medical center from 2010 to 2020. The study included patients ≥14 years of age with acute acetaminophen poisoning within 15 hours. The correlation between risk factors and detection of acetaminophen 15 hours after ingestion was evaluated using logistic regression, and the area under the curve (AUC) was calculated. Results: In total, 181 patients were included in the primary analysis; the median dose was 150.9 mg/kg and 35 patients (19.3%) had acetaminophen detected 15 hours after ingestion. The dose per weight and the time to visit were significant predictors for acetaminophen detection after 15 hours (odds ratio, 1.020 and 1.030, respectively). The AUCs were 0.628 for a 135 mg/kg cut-off value and 0.658 for a cut-off 450 minutes, and that of the combined model was 0.714 (sensitivity: 45.7%, specificity: 91.8%). Conclusion: Where acetaminophen concentrations are not reported during treatment following the UK guidelines, it is safe to start N-acetylcysteine immediately for patients who are ≥14 years old, visit within 15 hours after acute poisoning, and report having ingested ≥135 mg/kg. Additional N-acetylcysteine doses should be considered for patients visiting after 8 hours.

• Korean Journal of Radiology
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• 제25권2호
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• pp.189-198
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• 2024

Objective: To investigate the prognostic utility of radiomics features extracted from ¹⁸F-fluorodeoxyglucose (FDG) PET/CT combined with clinical factors and metabolic parameters in predicting progression-free survival (PFS) and overall survival (OS) in individuals diagnosed with extranodal nasal-type NK/T cell lymphoma (ENKTCL). Materials and Methods: A total of 126 adults with ENKTCL who underwent ¹⁸F-FDG PET/CT examination before treatment were retrospectively included and randomly divided into training (n = 88) and validation cohorts (n = 38) at a ratio of 7:3. Least absolute shrinkage and selection operation Cox regression analysis was used to select the best radiomics features and calculate each patient's radiomics scores (RadPFS and RadOS). Kaplan-Meier curve and Log-rank test were used to compare survival between patient groups risk-stratified by the radiomics scores. Various models to predict PFS and OS were constructed, including clinical, metabolic, clinical + metabolic, and clinical + metabolic + radiomics models. The discriminative ability of each model was evaluated using Harrell's C index. The performance of each model in predicting PFS and OS for 1-, 3-, and 5-years was evaluated using the time-dependent receiver operating characteristic (ROC) curve. Results: Kaplan-Meier curve analysis demonstrated that the radiomics scores effectively identified high- and low-risk patients (all P < 0.05). Multivariable Cox analysis showed that the Ann Arbor stage, maximum standardized uptake value (SUVmax), and RadPFS were independent risk factors associated with PFS. Further, β2-microglobulin, Eastern Cooperative Oncology Group performance status score, SUVmax, and RadOS were independent risk factors for OS. The clinical + metabolic + radiomics model exhibited the greatest discriminative ability for both PFS (Harrell's C-index: 0.805 in the validation cohort) and OS (Harrell's C-index: 0.833 in the validation cohort). The time-dependent ROC analysis indicated that the clinical + metabolic + radiomics model had the best predictive performance. Conclusion: The PET/CT-based clinical + metabolic + radiomics model can enhance prognostication among patients with ENKTCL and may be a non-invasive and efficient risk stratification tool for clinical practice.

• Asian Pacific Journal of Cancer Prevention
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• 제16권6호
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• pp.2527-2530
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• 2015

Background: The cancer of the prostate risk assessment (CAPRA) score has been defined to predict prostate cancer recurrence based on the pre-clinical data, then pathological data have also been incorporated. Thus, CAPRA post-surgical (CAPRA-S) score has been developed based on six criteria (prostate specific antigen (PSA) at diagnosis, pathological Gleason score, and information on surgical margin, seminal vesicle invasion, extracapsular extension and lymph node involvement) for the prediction of post-surgical recurrences. In the present study, biochemical recurrence (BCR)-free probabilities after open retropubic radical prostatectomy (RP) were evaluated by the CAPRA-S scoring system and its three-risk level model. Materials and Methods: CAPRA-S scores (0-12) of our 240 radical prostatectomies performed between January 2000-May 2011 were calculated. Patients were distributed into CAPRA-S score groups and also into three-risk groups as low, intermediate and high. BCR-free probabilities were assessed and compared using Kaplan-Meier analysis and Cox proportional hazards regression. Ability of CAPRA-S in BCR detection was evaluated by concordance index (c-index). Results: BCR was present in 41 of total 240 patients (17.1%) and the mean follow-up time was $51.7{\pm}33.0$ months. Mean BCR-free survival time was 98.3 months (95% CI: 92.3-104.2). Of the patients in low, intermediate and high risk groups, 5.4%, 22.0% and 58.8% had BCR, respectively and the difference among the three groups was significant (P = 0.0001). C-indices of CAPRA-S score and three-risk groups for detecting BCR-free probabilities in 5-yr were 0.87 and 0.81, respectively. Conclusions: Both CAPRA-S score and its three-risk level model well predicted BCR after RP with high c-index levels in our center. Therefore, it is a clinically reliable post-operative risk stratifier and disease recurrence predictor for prostate cancer.

• 대한토목학회논문집
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• 제2권1호
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• pp.53-62
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• 1982

본(本) 연구(硏究)는 우리 나라 전역(全城)에 걸쳐 자연상태(自然狀態) 혹은 농촌지역(農村地城)에 있어서의 소규모(小規模) 지역(地城) 배수(排水)를 위한 수문(水門)의 설계(設計) 배수량(排水量)을 결정(決定)하는 실용적(實用的) 방법(方法) 개발(開發)하기 위한 기초연구(基礎硏究)로서 장기간(長期間)의 비교적 정확한 단시간(短時間) 호우자료(豪雨資料)를 보유(保有)하고 있는 지표지점(指標地點)을 서울로 선택하여 단시간(短時間) 호우(豪雨) 최대우량(最大雨量)-지속기간(持續期間)-재현기간관계(再現期間關係)를 수립하고 전국(全國)에 산재해 있는 우량관측소(雨量觀測所)의 일우량(日雨量) 자료(資料)의 빈도분석(頻度分析)에 의해 전국(全國)을 몇 개의 유이(類以) 강우특성(降雨特性) 지역(地城)으로 구분(區分)하여 구분(區分)된 강우특성(降雨特性) 지역(地城)과 지표지점(指標地點)의 50년(年) 확률일우량(確率日雨量)에 의해 각(各) 지역(地域)의 강우능(降雨能) 계수(係數) 결정(決定)하였다. 또한 토지이용상태(土地利用狀態)와 토양형(土壤型)에 따라 그 유역(流域)을 대표(代表)하는 유출수(流出數)를 결정(決定)하고 재현기간별(再現期間別)로 유출수(流出數) 및 강우지속기간(降雨持續期間)에 따른 유출능계수(流出能係數)를 결정(決定)할 수 있는 노모그램을 작성(作成)하였다. 유역(流域)의 잠재유출량(潛在流出量)은 단위유량도(單位流量圖)의 기본이론(基本理論)에 의거 대상지역(對象地域)의 강우능계수(降雨能係數)와 유출능계수(流出能係數) 및 유역면적(流域面積)의 적(積)으로 표시하였으며 최대잠재유출량(最大潛在流出量)의 결정절차(決定節次)도 제시(提示)하였다.