Geant4를 활용한 국제우주정거장 내의 조직등가비례계수기 모의 실험

표정현,이재진,남욱원,김성환,김현옥,임창휘,박귀종,이대희,박영식,문명국,Pyo, Jeong-Hyun,Lee, Jae-Jin,Nam, Uk-Won,Kim, Sung-Hwan,Kim, Hyun-Ok,Lim, Chang-Hwy,Park, Kwi-Jong,Lee, Dae-Hee,Park, Young-Sik,Moon, Myung-Kook 한국천문학회 2012 天文學論叢 Vol.27 No.3

The International Space Station (ISS) orbits the Earth within the inner radiation belt, where high-energy protons are produced by collisions of cosmic rays to the upper atmosphere. About 6 astronauts stay in the ISS for a long period, and it should be important to monitor and assess the radiation environment in the ISS. The tissue equivalent proportional counter (TEPC) is an instrument to measure the impact of radiation on the human tissue. KASI is developing a TEPC as a candidate payload of the ISS. Before the detailed design of the TEPC, we performed simulations to test whether our conceptual design of the TEPC will work propertly in the ISS and to predict its performance. The simulations estimated that the TEPC will measure the dose equivalent of about 1:1 mSv during a day in the ISS, which is consistent with previous measurements.

Modal Stiffness reduction method의 개념을 적용한 보행자 보호용 Hood Structure의 Passive Design

표정현(JungHyun Pyo),홍정화(JungHwa Hong),김훈희(HunHee Kim),민성기(SungKi Min),고은영(EunYoung Ko) 한국자동차공학회 2010 한국자동차공학회 학술대회 및 전시회 Vol.2010 No.11

There have been many studies of passive systems in an effort to decrease the worst fatal head injuries in pedestrians from car accidents. A passive system of structural improvements in vehicles has been a major focus in the motor industry in an attempt to reduce the number road deaths and injuries. The HIC (head injury criterion) is a quantity for head injuries that was obtained by integrating the acceleration that is measured by a head-form impactor for a fixed amount of time. In general, the hood should be designed with lower stiffness to decrease the HIC value. This study introduced a method for decreasing the hood stiffness by making a hole on the inner hood panel. To determine the most effective hole position on the inner hood panel, the concept of modal stiffness was considered. The FRF (frequency response function) results for vehicle model on head-form impact simulation were obtained. In addition, modal analysis of the entire vehicle model was carried out simultaneously. Subsequently, using the results of these two analyses, adequate hole positions at each modal frequency were selected and the inner hood panel was improved by making a hole on these positions. Finally, through head-form impact simulations on the improved vehicle model with the hole, it was demonstrated that the new method applied in this study is acceptable and useful. In conclusion, the improved vehicle model with a 40㎜ diameter hole on the inner hood panel showed a significant reduction in the HIC; approximately 12.2% compared to the original vehicle model. A significant reduction in the HIC can be achieved by making only a single hole on the inner hood panel. In addition, this new method is incredibly effective and simple, and can be applied immediately to currently produced vehicles as well as to various impact studies including head-form impacts.

중심합성계획법을 이용한 보행자 HIC 영향에 대한 연구

표정현(JungHyun Pyo),황규현(GyuHyun Hwang),김훈희(HunHee Kim),고은영(EunYoung Ko),홍정화(JungHwa Hong) 한국자동차공학회 2011 한국자동차공학회 부문종합 학술대회 Vol.2011 No.5

Since the regulation for pedestrian protection was announced in Europe, both the passive and active systems for pedestrian protection have been investigated in motor industries and they are still continuing. Especially, the regulations of fatal head injury that could cause a pedestrian death were commonly included in the Euro Phase I, Ⅱ, and GTR(global technical regulation). Also these regulations are expected to be getting stricter. Generally, a hood-lifting system is well-known for typical active system that is related with a head injury. It was proved that the vehicle with this hood-lifting system causes massive HIC(head injury criterion) reduction comparing to one without the hood-lifting system. However, more advanced researches are still required on these active systems because the advanced researches could increase the stability and reduce the cost at the same time. On the other hand, although this passive system, which is related to its structure and material, shows relatively less HIC reduction, this system still preferred because of its strong stability and low-cost. In order to apply the passive design to the pipeline immediately, a simple design change method of the passive hood system was considered in this study. This study analyses the effect of the hood inner and hood outer with respect to pedestrian protection. The test condition was EuroNcap regulation. Then, the RSM(Response Surface method) was applied to optimization problem, and find the optimal thickness. In this study, it is the relationship between hood thickness and HIC (head injury criteria) for child headform-to-hood impact by investigating the analysis result.

Total Surface Area Is Useful for Differentiating between Aggressive and Favorable Multifocal Papillary Thyroid Carcinomas

표정수,손진희,강구현,김동훈,윤지섭 연세대학교의과대학 2015 Yonsei medical journal Vol.56 No.2

Purpose: The purpose of the present study was to identify more useful parameters for predicting behaviors of multifocal papillary thyroid carcinoma (PTC). Materials and Methods: We investigated dominant tumor diameter (TD), total tumor diameter(TTD), and total surface area (TSA) in tumors from 588 patients and evaluated their usefulness as parameters for assessment of tumor behaviors in multifocal PTCs. Results: In 588 PTCs, tumor multifocality was found in 179 PTCs (30.4%). Multifocal tumors were significantly associated with extrathyroidal extension, lymph node metastasis, and higher tumor stage grouping (p<0.001, p<0.001, and p<0.001, respectively). The rates of nodal metastasis increased with greater TSA and TTD in PTCs. Multifocal papillary thyroid microcarcinomas (mPMCs) with TSA >3.14 cm2 had higher rates of nodal metastasis than mPMCs with TSA ≤3.14 cm2 (p=0.038); however, there was no significant difference between mPMCs with TTD >1.0 cm and with TTD ≤1.0 cm (p=0.325). In addition, nodal metastasis was more frequent in mPMCs with TSA >3.14 cm2 than in unifocal papillary thyroid microcarcinomas(uPMCs) (TD ≤1.0 cm) (p=0.002), but not overt unifocal PTCs (TD >1.0 cm) (p=0.244). Conclusion: Our results suggest that mPMCs with TSA >3.14 cm2 show more aggressive behavior than uPMCs and mPMCs with TSA ≤3.14 cm2. TSA could be useful in distinguishing aggressive mPMCs from favorable cases.

Extranodal Follicular Dendritic Cell Sarcoma with Rapid Growth in Parapharynx: A Case Report

표정수,김동훈,강구현,도성임,채승완,김경은,이상혁,최윤라,최준혁,손진희 대한병리학회 2012 Journal of Pathology and Translational Medicine Vol.46 No.3

Follicular dendritic cell sarcoma (FDCS) is a rare malignancy arising from the antigen-presenting cells in the lymph node and extranodal tissue. We describe a 31-year-old male patient who presented with a swelling of the left parapharynx. The radiologic findings showed a 4.7×4.5×1.9 cm-sized, ill-defined mass in the left parapharyngeal space. A fine-needle aspiration cytology was performed and it showed scattered, irregular, cohesive clusters of tumor cells with a spindle-to-ovoid shape with irregular contours in a background of lymphocytes. Based on these findings, a diagnosis of spindle cell neoplasm was made. The surgically resected tumor was composed of elongated, ovoid or polygonal cells showing positive immunohistochemistry for CD21, CD23, and CD35. Postoperatively, the residual tumor was observed to undergo a rapidly growth. There is an overlap in the cytologic and histologic findings between FDCS of the parapharynx and other tumors. Pathologists should therefore be aware of its characteristics not only to provide an accurate diagnosis but also to recommend the appropriate clinical management.

MUC2 Expression Is Correlated with Tumor Differentiation and Inhibits Tumor Invasion in Gastric Carcinomas: A Systematic Review and Meta-analysis

표정수,손진희,강구현,김동훈,김경은,도인구,김동현 대한병리학회 2015 Journal of Pathology and Translational Medicine Vol.49 No.3

Background: While MUC2 is expressed in intestinal metaplasia and malignant lesions, the clinicopathological significance of MUC2 expression is not fully elucidated in gastric carcinoma (GC). Methods: The present study investigated the correlation between MUC2 expression and clinicopathological parameters in 167 human GCs. In addition, to confirm the clinicopathological significance of MUC2 expression, we performed a systematic review and meta-analysis in 1,832 GCs. Results: MUC2 expression was found in 58 of 167 GCs (34.7%). MUC2-expressing GC showed lower primary tumor (T), regional lymph node (N), and tumor node metastasis (TNM) stages compared with GCs without MUC2 expression (p = .001, p = .001, and p = .011, respectively). However, MUC2 expression was not correlated with Lauren’s classification and tumor differentiation. In meta-analysis, MUC2 expression was significantly correlated with differentiation and lower tumor stage (odds ratio [OR], 1.303; 95% confidence interval [CI], 1.020 to 1.664; p = .034 and OR, 1.352; 95% CI, 1.055 to 1.734; p = .017, respectively) but not with Lauren’s classification, pN stage, or pTNM stage. Conclusions: MUC2 expression was correlated with a lower tumor depth and lower lymph node metastasis in our study; the meta-analysis showed a correlation of MUC2 expression with tumor differentiation and lower tumor depth.

Diagnostic Test Accuracy Review of Cytology for Squamous Intraepithelial Lesion and Squamous Cell Carcinoma of Uterine Cervix

표정수,강구현,윤혜경,김현정 대한의학회 2019 Journal of Korean medical science Vol.34 No.2

Background: Even though cervico-vaginal smears have been used as a primary screening test for cervical carcinoma, the diagnostic accuracy has been controversial. The present study aimed to evaluate the diagnostic accuracy of cytology for squamous intraepithelial lesion (SIL) and squamous cell carcinoma (SqCC) of the uterine cervix through a diagnostic test accuracy (DTA) review. Methods: A DTA review was performed using 38 eligible studies that showed concordance between cytology and histology. In the DTA review, sensitivity, specificity, diagnostic odds ratio (OR), and the area under the curve (AUC) on the summary receiver operating characteristic (SROC) curve were calculated. Results: In the comparison between abnormal cytology and histology, the pooled sensitivity and specificity were 93.9% (95% confidence interval [CI], 93.7%–94.1%) and 77.6% (95% CI, 77.4–77.8%), respectively. The diagnostic OR and AUC on the SROC curve were 8.90 (95% CI, 5.57–14.23) and 0.8148, respectively. High-grade squamous intraepithelial lesion (HSIL) cytology had a higher sensitivity (97.6%; 95% CI, 94.7%–97.8%) for predicting HSIL or worse histology. In the comparison between SqCC identified on cytology and on histological analysis, the pooled sensitivity and specificity, diagnostic OR, and AUC were 92.7% (95% CI, 87.3%–96.3%), 87.5% (95% CI, 87.2%–87.8%), 865.81 (95% CI, 68.61–10,925.12), and 0.9855, respectively. Geographic locations with well-organized screening programs had higher sensitivity than areas with insufficient screening programs. Conclusion: These results indicate that cytology had a higher sensitivity and specificity for detecting SIL and SqCC of the uterine cervix during primary screening.

Core Needle Biopsy Is a More Conclusive Follow-up Method Than Repeat Fine Needle Aspiration for Thyroid Nodules with Initially Inconclusive Results: A Systematic Review and Meta-Analysis

표정수,손진희,강구현 대한병리학회 2016 Journal of Pathology and Translational Medicine Vol.50 No.3

Background: This study investigated the appropriate management of thyroid nodules with prior non-diagnostic or atypia of undetermined significance/follicular lesion of undetermined significance (AUS/FLUS) through a systematic review and meta-analysis. Methods: This study included 4,235 thyroid nodules from 26 eligible studies. We investigated the conclusive rate of follow-up core needle biopsy (CNB) or repeat fine needle aspiration (rFNA) after initial fine needle aspiration (FNA) with non-diagnostic or AUS/FLUS results. A diagnostic test accuracy (DTA) review was performed to determine the diagnostic role of the follow-up CNB and to calculate the area under the curve (AUC) on the summary receiver operating characteristic (SROC) curve. Results: The conclusive rates of follow-up CNB and rFNA after initial FNA were 0.879 (95% confidence interval [CI], 0.801 to 0.929) and 0.684 (95% CI, 0.627 to 0.736), respectively. In comparison of the odds ratios of CNB and rFNA, CNB had more frequent conclusive results than rFNA (odds ratio, 5.707; 95% CI, 2.530 to 12.875). Upon subgroup analysis, follow-up CNB showed a higher conclusive rate than rFNA in both initial non-diagnostic and AUS/FLUS subgroups. In DTA review of follow-up CNB, the pooled sensitivity and specificity were 0.94 (95% CI, 0.88 to 0.97) and 0.88 (95% CI, 0.84 to 0.91), respectively. The AUC for the SROC curve was 0.981, nearing 1. Conclusions: Our results show that CNB has a higher conclusive rate than rFNA when the initial FNA produced inconclusive results. Further prospective studies with more detailed criteria are necessary before follow-up CNB can be applied in daily practice.

Clinicopathological Significance and Diagnostic Accuracy of c-MET Expression by Immunohistochemistry in Gastric Cancer: A Meta-Analysis

표정수,강구현,조현진 대한위암학회 2016 Journal of gastric cancer Vol.16 No.3

Purpose: The aim of the present study was to elucidate the clinicopathological significance and diagnostic accuracy of immunohistochemistry (IHC) for determining the mesenchymal epidermal transition (c-MET) expression in patients with gastric cancer (GC). Materials and Methods: The present meta-analysis investigated the correlation between c-MET expression as determined by IHC and the clinicopathological parameters in 8,395 GC patients from 37 studies that satisfied the eligibility criteria. In addition, a concordance analysis was performed between c-MET expression as determined by IHC and c-MET amplification, and the diagnostic test accuracy was reviewed. Results: The estimated rate of c-MET overexpression was 0.403 (95% confidence interval [CI], 0.327~0.484) and it was significantly correlated with male patients, poor differentiation, lymph node metastasis, higher TNM stage, and human epidermal growth factor receptor 2 (HER2) positivity in IHC analysis. There was a significant correlation between c-MET expression and worse overall survival rate (hazard ratio, 1.588; 95% CI, 1.266~1.992). The concordance rates between c-MET expression and c-MET amplification were 0.967 (95% CI, 0.916~0.987) and 0.270 (95% CI, 0.173~0.395) for cases with non-overexpressed and overexpressed c-MET , respectively. In the diagnostic test accuracy review, the pooled sensitivity and specificity were 0.56 (95% CI, 0.50~0.63) and 0.79 (95% CI, 0.77~0.81), respectively. Conclusions: The c-MET overexpression as determined by IHC was significantly correlated with aggressive tumor behavior and positive IHC status for HER2 in patients with GC. In addition, the c-MET expression status could be useful in the screening of c-MET amplification in patients with GC.

공군 정찰기를 이용한 우주방사선 측정 실험

이재진,표정현,권용준,남욱원,김성환 대한방사선방어학회 2015 대한방사선방어학회 학술발표회 논문요약집 Vol.2015 No.10