중전기기 산업의 발전방향

정춘기,Jeong, Chun-Gi 기술표준원 2003 기술표준 Vol.15 No.-

KS 규격 개정에 따른 피뢰설비 시스템

정춘기 대한전기협회 2002 전기저널 Vol.- No.311

Causal Inference Network of Genes Related with Bone Metastasis of Breast Cancer and Osteoblasts Using Causal Bayesian Networks

박성배,정춘기,Efrain Gonzalez,유창원 대한골대사학회 2018 대한골대사학회지 Vol.25 No.4

Background: The causal networks among genes that are commonly expressed in osteoblasts and during bone metastasis (BM) of breast cancer (BC) are not well understood. Here, we developed a machine learning method to obtain a plausible causal network of genes that are commonly expressed during BM and in osteoblasts in BC. Methods: We selected BC genes that are commonly expressed during BM and in osteoblasts from the Gene Expression Omnibus database. Bayesian Network Inference with Java Objects (Banjo) was used to obtain the Bayesian network. Genes registered as BC related genes were included as candidate genes in the implementation of Banjo. Next, we obtained the Bayesian structure and assessed the prediction rate for BM, conditional independence among nodes, and causality among nodes. Furthermore, we reported the maximum relative risks (RRs) of combined gene expression of the genes in the model. Results: We mechanistically identified 33 significantly related and plausibly involved genes in the development of BC BM. Further model evaluations showed that 16 genes were enough for a model to be statistically significant in terms of maximum likelihood of the causal Bayesian networks (CBNs) and for correct prediction of BM of BC. Maximum RRs of combined gene expression patterns showed that the expression levels of UBIAD1, HEBP1, BTNL8, TSPO, PSAT1, and ZFP36L2 significantly affected development of BM from BC. Conclusions: The CBN structure can be used as a reasonable inference network for accurately predicting BM in BC.

Health Care Burden of Spinal Diseases in the Republic of Korea: Analysis of a Nationwide Database From 2012 Through 2016

이창현,정춘기,김치헌,권지웅 대한척추신경외과학회 2018 Neurospine Vol.15 No.1

Objective: This study aimed to determine the incidence and analyze trends related to spinal diseases based on a national database in the Republic of Korea (ROK) and to elucidate the healthcare burden that will serve as a useful resource for researchers, clinicians, and patients. Methods: This study was a retrospective analysis of data obtained from Healthcare Bigdata Hub, the Korean Statistical Information Service, and Open Data Portal from 2012 through 2016. The main disease codes for spinal diseases (M40–M54) were used for identification of these conditions. Results: The overall annual incidence rates for spinal disease in the ROK was median 15,877 (men, 13,181; women, 18,588) per 100,000 population, and sex ratio was 1:1.41 (p<0.01). The incidence rate and annual costs per patient increased by 7.6% and 14.7% over 5 years continuously, respectively. The age-adjusted incidence rate increased with age; the highest rates were 42.6% in the 75–79 years group. Patients older than 65 years old accounted for median 31.0% of number of patients and 40.1% of medical expenses over 5 years. Lumbar disc herniation (M51) and spinal stenosis (M48) might accounted for both the highest incidence and medical expenses in patients under the age of 60 and over 60 years, respectively. Conclusion: The incidence and medical expenditures of spinal disease increased continuously. As the population of ROK in aging, the incidence and medical expenditures due to spondylosis and stenosis (M48) for the old are also increasing. The social burden of spinal diseases in elder patients needs to be prudently considered in health policy makers.

Mechanical Failure After Total En Bloc Spondylectomy and Salvage Surgery

권신원,정춘기,원영일,여운탁,박성배,양승헌,이창현,John M. Rhee,김경태,김치헌 대한척추신경외과학회 2022 Neurospine Vol.19 No.1

Objective: Total en bloc spondylectomy (TES) is a curative surgical method for spinal tumors. After resecting the 3 spinal columns, reconstruction is of paramount importance. We present cases of mechanical failure and suggest strategies for salvage surgery. Methods: The medical records of 19 patients who underwent TES (9 for primary tumors and 10 for metastatic tumors) were retrospectively reviewed. Previously reported surgical techniques were used, and the surgical extent was 1 level in 16 patients and 2 levels in 3 patients. A titanium-based mesh-type interbody spacer filled with autologous and cadaveric bone was used for anterior support, and a pedicle screw/rod system was used for posterior support. Radiotherapy was performed in 11 patients (pre-TES, 5; post-TES, 6). They were followed up for 59 ± 38 months (range, 11–133 months). Results: During follow-up, 8 of 9 primary tumor patients (89%) and 5 of 10 metastatic tumor patients (50%) survived (mean survival time, 124 ± 8 months vs. 51 ± 13 months; p = 0.11). Mechanical failure occurred in 3 patients (33%) with primary tumors and 2 patients (20%) with metastatic tumors (p = 0.63). The mechanical failure-free time was 94.4 ± 14 months (primary tumors, 95 ± 18 months; metastatic tumors, 68 ± 16 months; p = 0.90). Revision surgery was performed in 4 of 5 patients, and bilateral broken rods were replaced with dual cobalt-chromium alloy rods. Repeated rod fractures occurred in 1 of 4 patients 2 years later, and the third operation (with multiple cobalt-chromium alloy rods) was successful for over 6 years. Conclusion: Considering the difficulty of reoperation and patients’ suffering, preemptive use of a multiple-rod system may be advisable.

Magnetoencephalography in pediatric epilepsy

김훈민,정춘기,황희,정천기 대한소아청소년과학회 2013 Clinical and Experimental Pediatrics (CEP) Vol.56 No.10

Magnetoencephalography (MEG) records the magnetic field generated by electrical activity of cortical neurons. The signal is not distorted or attenuated, and it is contactless recording that can be performed comfortably even for longer than an hour. It has excellent and decent temporal resolution, especially when it is combined with the patient’s own brain magnetic resonance imaging (magnetic source imaging). Data of MEG and electroencephalography are not mutually exclusive and it is recorded simultaneously and interpreted together. MEG has been shown to be useful in detecting the irritative zone in both lesional and nonlesional epilepsy surgery. It has provided valuable and additive information regarding the lesion that should be resected in epilepsy surgery. Better outcomes in epilepsy surgery were related to the localization of the irritative zone with MEG. The value of MEG in epilepsy surgery is recruiting more patients to epilepsy surgery and providing critical information for surgical planning. MEG cortical mapping is helpful in younger pediatric patients, especially when the epileptogenic zone is close to the eloquent cortex. MEG is also used in both basic and clinical research of epilepsy other than surgery. MEG is a valuable diagnostic modality for diagnosis and treatment, as well as research in epilepsy.

대전방지처리된 물질의 정전기 대전특성에 관한 연구

이덕출,장영민,정재희,이관형,차영식,정춘기 한국산업안전학회 1995 한국안전학회지 Vol.10 No.1

There are many methods to move or reduce the static electricity which often causes disasters in industry, etc. The methods may include grounding of a potentially-charged body, use of antistatic materials, humidification of an atmosphere, use of static electricity eliminators. Among those methods, the one utilizing antistatic materials is widely used in the industrial fields due to its effectiveness and inexpectiveness. In Korea, safety regulations and technical standards are not sufficient for applying to industrial fields as electrostatic disaster prevention measures due to the shortage of practically verified and reliable data. The propose of this paper is to examine the electrostatic characteristics of the antistatic materials and non-antistatic ordinary materials under the various conditions of different temperature and humidity.

Pathological Classification of the Intramedullary Spinal Cord Tumors According to 2021 World Health Organization Classification of Central Nervous System Tumors, a Single-Institute Experience

박성혜,원재경,김치헌,피지훈,김승기,최승홍,정춘기 대한척추신경외과학회 2022 Neurospine Vol.19 No.3

According to the new 2021 World Health Organization (WHO) classification of tumors of the central nervous system (CNS) the classification of the primary intramedullary spinal cord tumors (IM-SCT) follows that of CNS tumors. However, since the genetics and methylation profile of ependymal tumors depend on the location of the tumor, the ‘spinal (SP)’ should be added for the ependymoma (EPN) and subependymoma (SubEPN). For an evidence-based review, the authors reviewed SCTs in the archives of the Seoul National University Hospital over the past decade. The frequent pathologies of primary IM-SCT were SP-EPN (45.1%), hemangioblastoma (20.0%), astrocytic tumors (17.4%, including pilocytic astrocytoma [4.6%] and diffuse midline glioma, H3 K27-altered [4.0%]), myxopapillary EPN (11.0%), and SP-subEPN (3.0%) in decreasing order. IDH-mutant astrocytomas, oligodendrogliomas, glioneuronal tumors, embryonal tumors, and germ cell tumors can occur but are extremely rare in the spinal cord. Genetic studies should support for the primary IM-SCT classification. In the 2021 WHO classifications, extramedullary SCT did not change significantly but contained several new genetically defined types of mesenchymal tumors. This article focused on primary IM-SCT for tumor frequency, age, sex difference, pathological features, and genetic abnormalities, based on a single-institute experience.

Development and Validation of an Online Calculator to Predict Proximal Junctional Kyphosis After Adult Spinal Deformity Surgery Using Machine Learning

이창현,조대진,오재근,현승재,박진훈,김경현,배준석,문봉주,이창규,신명훈,장현준,한문수,김치헌,정춘기,문승명 대한척추신경외과학회 2023 Neurospine Vol.20 No.4

Objective: Although adult spinal deformity (ASD) surgery aims to restore and maintain alignment, proximal junctional kyphosis (PJK) may occur. While existing scoring systems predict PJK, they predominantly offer a generalized 3-tier risk classification, limiting their utility for nuanced treatment decisions. This study seeks to establish a personalized risk calculator for PJK, aiming to enhance treatment planning precision. Methods: Patient data for ASD were sourced from the Korean spinal deformity database. PJK was defined a proximal junctional angle (PJA) of ≥ 20° at the final follow-up, or an increase in PJA of ≥ 10° compared to the preoperative values. Multivariable analysis was performed to identify independent variables. Subsequently, 5 machine learning models were created to predict individualized PJK risk post-ASD surgery. The most efficacious model was deployed as an online and interactive calculator. Results: From a pool of 201 patients, 49 (24.4%) exhibited PJK during the follow-up period. Through multivariable analysis, postoperative PJA, body mass index, and deformity type emerged as independent predictors for PJK. When testing machine learning models using study results and previously reported variables as hyperparameters, the random forest model exhibited the highest accuracy, reaching 83%, with an area under the receiver operating characteristics curve of 0.76. This model has been launched as a freely accessible tool at: (https:// snuspine.shinyapps.io/PJKafterASD/). Conclusion: An online calculator, founded on the random forest model, has been developed to gauge the risk of PJK following ASD surgery. This may be a useful clinical tool for surgeons, allowing them to better predict PJK probabilities and refine subsequent therapeutic strategies.