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Diagnostic Value of C-reactive Protein in Complicated Appendicitis
문형민,박범석,문덕진 대한대장항문학회 2011 Annals of Coloproctolgy Vol.27 No.3
Purpose: Early detection of appendicitis has increased due to development of computed tomography and ultrasonography,yet we are frequently meeting complicated appendicitis, including perforation, abscess and a gangrenous appendicitis due to delayed diagnosis. For that reason, we want to evaluate predictive factors for the complicated appendicitis. Methods: A total of 128 patients with appendicitis, after 13 patients with a duration of under 12 hours and 15 patients with pathological non-appendicitis were excluded from 156 patients, who visited Kwangju Christian Hospital from November 2008 to November 2010 were retrospectively reviewed. Results: There were 62 patients (48.3%) with simple appendicitis and 66 patients (51.7%) with complicated appendicitis. In univariate analysis, age (P < 0.001), C-reactive protein (P < 0.001) and the diameter of the appendix (P = 0.006), were found to be significant. Multivariate analysis demonstrated that C-reactive protein was an independent predictor for complicated appendicitis (odds ratio, 1.371; 95% confidence interval, 1.155 to 1.628; P < 0.001). The cut-off value of C-reactive protein was set at 7.05 mg/dL by using receiver operating characteristic curve (0.805; sensitivity, 57.6%; specificity, 98.3%). Conclusion: This study suggests that if C-reactive protein is above 7.05 mg/dL, immediate and proper management should be performed due to a high probability of complicated appendicitis, especially in young children or elderly patients who frequently present with vague symptoms.
1-3형 압전복합재료 등가물성 직접 추출 기법의 정확도 분석
노응휘,김동현,문형민,장우석,윤홍우,표성훈,김경섭,조요한 한국음향학회 2023 韓國音響學會誌 Vol.42 No.5
본 논문에서는 1-3형 압전복합재료를 단일상의 균질 압전매질로 모델링하기 위해 필요한 등가의 물성을 유한요소 해석으로 직접 추출하는 기법의 정확도를 다룬다. 직접 추출 기법은 압전재료의 전기적, 기계적 거동과 상호 간커플링을 기술하는 구성방정식을 기반으로 물성 행렬의 개별 성분들을 직접적으로 산출하는 방법이다. 직접 추출에사용되는 두 가지 구성방정식 조합 간의 정확도를 비교하기 위하여 단일 1-3형 압전복합재료 하이드로폰을 대상으로등가물성과 수신감도를 산출하고 전체 영역에 대한 유한요소 해석 결과와 비교한다. 물성 추출의 정확도는 압전복합재료를 구성하는 폴리머의 탄성 특성과 밀접한 관련이 있음을 확인하고, 오차 원인을 분석하여 정확한 등가물성 산출을 위한 가이드라인을 제시한다. 압전복합재료 하이드로폰과 주변의 음향구조물을 포함하는 스테이브 규모에 대해서도 등가 모델링을 적용하여 추출된 물성의 정확도와 연산량 감소를 확인한다. This paper presents accuracy of a method that directly estimates equivalent properties of a 1-3 piezocomposite for modeling it into the single phase homogeneous piezomaterial. This direct estimation method finds individual components of a material property matrix based on the piezoelectric constitutive equations, which represent mechanical and electrical behaviors and their couplings. Equivalent properties on a single 1-3 piezocomposite hydrophone are derived, and their accuracy depending on pairing of the constitutive equations is investigated by comparing them with finite element analysis for the whole domain. The accuracy is related to elastic characteristics of a matrix polymer, and the error is analyzed so that some guidelines for correct estimation are suggested. Fidelity of estimated properties and equivalent modeling is shown in a stave scale including hydrophones and surrounding acoustic structures as well, and reduced computational cost is verified.