• Clinical and Experimental Reproductive Medicine
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• 제48권2호
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• pp.163-173
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• 2021

Objective: This study aimed to characterize a validated model for predicting oocyte retrieval in controlled ovarian stimulation (COS) and to construct model-based nomograms for assistance in clinical decision-making regarding the gonadotropin protocol and dose. Methods: This observational, retrospective, cohort study included 636 women with primary unexplained infertility and a normal menstrual cycle who were attempting assisted reproductive therapy for the first time. The enrolled women were split into an index group (n=497) for model building and a validation group (n=139). The primary outcome was absolute oocyte count. The dose-response relationship was tested using modified Poisson, negative binomial, hybrid Poisson-E_max, and linear models. The validation group was similarly analyzed, and its results were compared to that of the index group. Results: The Poisson model with the log-link function demonstrated superior predictive performance and precision (Akaike information criterion, 2,704; λ=8.27; relative standard error (λ)=2.02%). The covariate analysis included women's age (p<0.001), antral follicle count (p<0.001), basal follicle-stimulating hormone level (p<0.001), gonadotropin dose (p=0.042), and protocol type (p=0.002 and p<0.001 for short and antagonist protocols, respectively). The estimates from 500 bootstrap samples were close to those of the original model. The validation group showed model assessment metrics comparable to the index model. Based on the fitted model, a static nomogram was built to improve visualization. In addition, a dynamic electronic tool was created for convenience of use. Conclusion: Based on our validated model, nomograms were constructed to help clinicians individualize the stimulation protocol and gonadotropin doses in COS cycles.

• The Journal of Advanced Prosthodontics
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• 제16권3호
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• pp.151-162
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• 2024

PURPOSE. This study aimed to analyze factors influencing the success and failure of implant prostheses and to estimate the lifespan of prostheses using standardized evaluation criteria. An online survey platform was utilized to efficiently gather large samples from multiple institutions. MATERIALS AND METHODS. During the one-year period, patients visiting 16 institutions were assessed using standardized evaluation criteria (KAP criteria). Data from these institutions were collected through an online platform, and various statistical analyses were conducted. Risk factors were assessed using both the Cox proportional hazard model and Cox regression analysis. Survival analysis was conducted using Kaplan-Meier analysis and nomogram, and lifespan prediction was performed using principal component analysis. RESULTS. The number of patients involved in this study was 485, with a total of 841 prostheses evaluated. The median survival was estimated to be 16 years with a 95% confidence interval. Factors found to be significantly associated with implant prosthesis failure, characterized by higher hazard ratios, included the 'type of clinic', 'type of antagonist', and 'plaque index'. The lifespan of implant prostheses that did not fail was estimated to exceed the projected lifespan by approximately 1.34 years. CONCLUSION. To ensure the success of implant prostheses, maintaining good oral hygiene is crucial. The estimated lifespan of implant prostheses is often underestimated by approximately 1.34 years. Furthermore, standardized form, online platform, and visualization tool, such as nomogram, can be effectively utilized in future follow-up studies.

• Korean Journal of Radiology
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• 제25권1호
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• pp.74-85
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• 2024

Objective: Idiopathic intracranial hypertension (IIH) is a condition of unknown etiology associated with venous sinus stenosis. This study aimed to develop a magnetic resonance venography (MRV)-based radiomics model for predicting a high trans-stenotic pressure gradient (TPG) in IIH patients diagnosed with venous sinus stenosis. Materials and Methods: This retrospective study included 105 IIH patients (median age [interquartile range], 35 years [27-42 years]; female:male, 82:23) who underwent MRV and catheter venography complemented by venous manometry. Contrast enhanced-MRV was conducted under 1.5 Tesla system, and the images were reconstructed using a standard algorithm. Shape features were derived from MRV images via the PyRadiomics package and selected by utilizing the least absolute shrinkage and selection operator (LASSO) method. A radiomics score for predicting high TPG (≥ 8 mmHg) in IIH patients was formulated using multivariable logistic regression; its discrimination performance was assessed using the area under the receiver operating characteristic curve (AUROC). A nomogram was constructed by incorporating the radiomics scores and clinical features. Results: Data from 105 patients were randomly divided into two distinct datasets for model training (n = 73; 50 and 23 with and without high TPG, respectively) and testing (n = 32; 22 and 10 with and without high TPG, respectively). Three informative shape features were identified in the training datasets: least axis length, sphericity, and maximum three-dimensional diameter. The radiomics score for predicting high TPG in IIH patients demonstrated an AUROC of 0.906 (95% confidence interval, 0.836-0.976) in the training dataset and 0.877 (95% confidence interval, 0.755-0.999) in the test dataset. The nomogram showed good calibration. Conclusion: Our study presents the feasibility of a novel model for predicting high TPG in IIH patients using radiomics analysis of noninvasive MRV-based shape features. This information may aid clinicians in identifying patients who may benefit from stenting.

• Korean Journal of Radiology
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• 제24권7호
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• pp.668-680
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• 2023

Objective: To compare multiparametric magnetic resonance imaging (MRI) features of intraductal carcinoma of the prostate (IDC-P) with those of prostatic acinar adenocarcinoma (PAC) and develop prediction models to distinguish IDC-P from PAC and IDC-P with a high proportion (IDC ≥ 10%, hpIDC-P) from IDC-P with a low proportion (IDC < 10%, lpIDC-P) and PAC. Materials and Methods: One hundred and six patients with hpIDC-P, 105 with lpIDC-P and 168 with PAC, who underwent pretreatment multiparametric MRI between January 2015 and December 2020 were included in this study. Imaging parameters, including invasiveness and metastasis, were evaluated and compared between the PAC and IDC-P groups as well as between the hpIDC-P and lpIDC-P subgroups. Nomograms for distinguishing IDC-P from PAC, and hpIDC-P from lpIDC-P and PAC, were made using multivariable logistic regression analysis. The discrimination performance of the models was assessed using the receiver operating characteristic area under the curve (ROC-AUC) in the sample, where the models were derived from without an independent validation sample. Results: The tumor diameter was larger and invasive and metastatic features were more common in the IDC-P than in the PAC group (P < 0.001). The distribution of extraprostatic extension (EPE) and pelvic lymphadenopathy was even greater, and the apparent diffusion coefficient (ADC) ratio was lower in the hpIDC-P than in the lpIDC-P group (P < 0.05). The ROC-AUCs of the stepwise models based solely on imaging features for distinguishing IDC-P from PAC and hpIDC-P from lpIDC-P and PAC were 0.797 (95% confidence interval, 0.750-0.843) and 0.777 (0.727-0.827), respectively. Conclusion: IDC-P was more likely to be larger, more invasive, and more metastatic, with obviously restricted diffusion. EPE, pelvic lymphadenopathy, and a lower ADC ratio were more likely to occur in hpIDC-P, and were also the most useful variables in both nomograms for predicting IDC-P and hpIDC-P.

• Neonatal Medicine
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• 제17권1호
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• pp.102-108
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• 2010

목 적 : 신생아 황달은 신생아기에 가장 흔한 질환 중 하나로 핵황달과 같은 심각한 후유증을 유발할 수 있기 때문에 조기발견과 치료가 중요하다. 본 연구에서는 경피적 황달 측정을 이용하여 황달 수치(TcB)를 측정하고 황달 수치의 변화를 노모그램으로 산출해 건강한 신생아황달의 자연경과를 살펴보고 추적 관찰과 치료가 필요한경우를 예측하고자 하였다. 방 법: 2007년 10월 1일부터 2009년 4월 30일까지 성애병원에서 출생한 재태연령 35주 이상의 건강한 만삭아와 준만삭아 중 부모가 모두 한국인인 986명을 대상으로 하였다. 출생 6시간 후부터 6시간 간격으로 퇴원시까지 경피적 황달 측정기(Minolta, JM-103)을 이용하여 이마에서 측정하였으며 이를 통해 얻어진 데이터로 노모그램을 산출하였다. 분만방법, 재태연령, 수유방법에 따른 차이를 비교하였다. 결 과 : 통계 데이터를 통해 시간에 따른 백분위수 그래프가 그려졌으며, 재태기간 35주에서 37주 6일의 신생아에서는 90 백분위수 이상, 38주 이상은 95 백분위수 이상에서 광선치료가 필요할 것으로 나타났다. 생후 24시간, 48시간, 72시간, 96시간에 TcB 수치의 평균을 분만방법, 재태연령, 수유방법에 따라 비교하였을 때 생후 48시간에서 제왕절개로 출생한 신생아가 자연분만으로 출생한 신생아에 비해 TcB 수치가 의미 있게 높았으며, 나머지 시간에서는 통계학적 의미가 없었다. 이외 수유방법에 따른 두 군의 비교에서는 모든 시간에서 통계학적 유의성이 없었다. 결 론 : 편리하고 비침습적인 경피적 황달 측정기를 이용하여 시간에 따른 TcB 수치의 변화를 노모그램을 산출하였으며 이를 이용하여 심각한 황달을 예측하는데 도움이 될 것으로 사료된다.

• 대한임상독성학회지
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• 제6권1호
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• pp.1-8
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• 2008

Acetaminophen (AAP) overdose can result in potentially serious hepatotoxicity. The ingested dose and time from ingestion to presentation are important prognostic factors. Toxic dose in adult is thought to be at least 10 g or 200 mg/kg. However, early management of acute overdose should be guided by the plasma AAP concentration. The antidote for AAP poisoning is N-acetylcysteine (NAC). It provides complete protection against hepatotoxicity if given within 8 h of acute overdose. If the concentration is above the possible toxicity line as predicted by the Rumack-Matthew nomogram, either the 72-hr oral or the 20-hr intravenous NAC regimen should be administered. NAC is also effective if started late in patients with established hepatic failure. This article summarizes the current consensus of clinical assessment and management for acute AAP overdose.

• Management Science and Financial Engineering
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• 제2권1호
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• pp.103-122
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• 1996

This paper presents an easily used graphical procedure for simultaneous estimation of the index, skewness, scale, and location parameters of the stable laws. First, the index $\alpha$ and skewness $\beta$ are estimated through the joint use of a tail length statistic $\widetilde{K_t}$ and a skewness statistic $\widetilde{K_s}$, both of which are functions of order statistics. Next, the function of order statistics needed for estimation of scale $\sigma$ and location $\mu$ are determined from a nomogram indexed on the estimates of $\alpha$ and $\beta$. Some applications and examples are provided.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 1992년도 추계학술대회논문집; 반도아카데미, 20 Nov. 1992
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• pp.14-18
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• 1992

진동을 제어하는 방법의 하나로 널리 응용되고 있는 진동감쇠 제어기술은 급속한 산업화에 부수되는 불필요한 진동이나 소음을 효과적으로 줄이기 위 하여 광범위하게 연구되어 오고 있다. 특히 수동감쇠제어는 기존의 구조물에 단지 표면처리등의 간단한 작업을 통해 큰 감쇠효과를 얻을 수 있을 뿐 아 니라 수명도 반영구적이고 사용장소의 구애를 거의 받지 않는다는 장점 때 문에 그 수요가 증가하고 있는 실정이다[1]. 그러나 대표적인 수동감쇠재료 인 점탄성재료는 우수한 감쇠성질을 가지고 있음에도 불구하고, 재료 자체가 주위환경에 따라 감쇠특성 및 물성치가 민감하게 변화하기 때문에 이 재료 로 감쇠처리된 구조물에는 유한요소법과 같은 구조해석기법을 응용하는 것 이 쉽지않다는 단점이 있다[2]. 따라서 본 연구에서는 이러한 제약을 극복하 기 위하여, 모우드해석법을 통해 유도된 점탄성재료의 주파수와 온도에 대한 특성치를 보여주는 Reduced Frequency Nomogram(RFN)을 전산화과정을 거쳐 그래프화 하여 미지의 온도와 주파수에서 특성치를 구할 수 있도록 하 였다. 이 자료를 근거로 점탄성 재료를 포함한 실제 구조물의 이론적인 해석 을 가능하게 함으로써 이 재료의 광범위한 활용을 도모하였다.

• 터널과지하공간
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• 제5권2호
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• pp.89-94
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• 1995

Regression analysis and a comparative study were carried out for 52 blast vibration data which were monitored by changing the monitoring distance and charge per delay. The results are as follows: 1) The square and cube root scalings and general equation which have a confidence level at the point of 90% and 99% are V90=33300(SD)-2.026 , V90=23600(SD)-1.993, V90=26300W0.755 R-2.007 and V99=48400(SD)-2.026, V99=34000(SD)-1.993 , V99=38100W0.755R-2.007, respectively. 2) There is need to decide the allowable max. charge weight per delay considering the cross points comparatively of the nomogram constructed using several predictived equations. 3) It is necessary to derive the predictive equation on the basis of blast vibration level monitored in field and to decide safe vibration level and the confidence level.

• 한국자동차공학회논문집
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• 제10권5호
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• pp.138-146
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• 2002

The new type of vibration reduction material far an automotive interior, which is spray-type liquid material, is developed in this study The new material has better damping property and lower mass density than other damping materials, for example asphalt sheet. It can be sprayed by an automatic robot, so it is expected to improve productivity and cut down manpower. And it solves a poor adhesion problem and makes an automotive to be lightweight by optimizing spray process. So, It is a next generation automotive vibration reduction material. In this paper, the chemical process for making the new damping materials is described. And then, the damping properties of the vibration reduction materials are analyzed by modal testing of damping treatment specimens. The new vibration reduction materials have good damping properties than asphalt sheet in the experimental results.