• Investigative Magnetic Resonance Imaging
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• 제26권1호
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• pp.32-42
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• 2022

Purpose: To evaluate the clinical benefit of 2D contrast-enhanced T2 fluid-attenuated inversion recovery (CE-T2 FLAIR) image for detecting leptomeningeal metastasis (LM) in the brain metastasis work-up for lung cancer. Materials and Methods: From June 2017 to July 2019, we collected all consecutive patients with lung cancer who underwent brain magnetic resonance image (MRI), including contrast-enhanced 3D fast spin echo T1 black-blood image (CE-T1WI) and CE-T2 FLAIR; we recruited clinico-radiologically suspected LM cases. Two independent readers analyzed the images for LM in three sessions: CE-T1WI, CE-T2 FLAIR, and their combination. Results: We recruited 526 patients with suspected lung cancer who underwent brain MRI; of these, we excluded 77 (insufficient image protocol, unclear pathology, different contrast media, poor image quality). Of the 449 patients, 34 were clinico-radiologically suspected to have LM; among them, 23 were diagnosed with true LM. The calculated detection performance of CE-T1WI, CE-T2 FLAIR, and combined analysis obtained from the 34 suspected LM were highest in the combined analysis (AUC: 0.80, 0.82, and 0.89, respectively). The inter-observer agreement was also the highest in the combined analysis (0.68, 0.72, and 0.86, respectively). In quantitative analyses, CNR of CE-T2 FLAIR was significantly higher than that of CE-T1WI (Wilcoxon signed rank test, P < 0.05). Conclusion: Adding CE-T2 FLAIR might provide better detection for LM in the brain-metastasis screening for lung cancer.

• Journal of Microbiology and Biotechnology
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• 제29권12호
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• pp.1969-1974
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• 2019

A Gram-staining-negative, aerobic, light brown pigment bacterium, designated strain CE80^T was isolated from marine sponge Callyspongia elegans in Jeju Island, Republic of Korea. Strain CE80^T grew optimally at 25℃, in the range of pH 5.0-11.0 (optimum 7.0-8.0), and with 1.0-5.0% NaCl (optimum 1-3% (w/v)). Phylogenetic analysis based on the 16S rRNA gene sequence showed that strain CE80^T belonged to the genus Labrenzia and was closely related to L. suaedae YC6927^T (98.3%), L. alexandrii DFL-11^T (96.6%), L. aggregata IAM 12614^T (96.6%) L. marina mano18^T (96.5%) and L. alba CECT 5094^T (96.2%). The major fatty acids of strain CE80^T were C_18:1 ω7c, and summed feature. The polar lipids were diphosphatidylglycerol, phosphatidylcholine, phosphatidylethanolamine, phosphatidylglycerol, phosphatidylmonomethylethanolamin, one unidentified aminolipid, one phospholipid and four unidentified lipids. The DNA G+C content of strain CE80^T was 55.9 mol%. The major respiratory quinone was Q-10. DNA-DNA relatedness between strain CE80^T and L. suaedae YC6927^T was 56.1±2.8%. On the basis of physiological and biochemical characterization and phylogenetic and chemotaxonomic analysis, strain CE80^T represents a novel species of the Labrenzia, for which the name Labrenzia callyspongiae sp. nov., is proposed. The type strain is CE80^T (=KCTC 42849^T =JCM 31309^T).

• Investigative Magnetic Resonance Imaging
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• 제25권2호
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• pp.118-128
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• 2021

Purpose: To investigate the value of MR textural analysis, including use of diffusion-weighted imaging (DWI) to differentiate malignant from benign soft-tissue tumors on 3T MRI. Materials and Methods: We enrolled 69 patients (25 men, 44 women, ages 18 to 84 years) with pathologically confirmed soft-tissue tumors (29 benign, 40 malignant) who underwent pre-treatment 3T-MRI. We calculated MR texture, including mean, standard deviation (SD), skewness, kurtosis, mean of positive pixels (MPP), and entropy, according to different spatial-scale factors (SSF, 0, 2, 4, 6) on axial T1- and T2-weighted images (T1WI, T2WI), contrast-enhanced T1WI (CE-T1WI), high b-value DWI (800 sec/mm²), and apparent diffusion coefficient (ADC) map. We used the Mann-Whitney U test, logistic regression, and area under the receiver operating characteristic curve (AUC) for statistical analysis. Results: Malignant soft-tissue tumors had significantly lower mean values of DWI, ADC, T2WI and CE-T1WI, MPP of ADC, and CE-T1WI, but significantly higher kurtosis of DWI, T1WI, and CE-T1WI, and entropy of DWI, ADC, and T2WI than did benign tumors (P < 0.050). In multivariate logistic regression, the mean ADC value (SSF, 6) and kurtosis of CE-T1WI (SSF, 4) were independently associated with malignancy (P ≤ 0.009). A multivariate model of MR features worked well for diagnosis of malignant soft-tissue tumors (AUC, 0.909). Conclusion: Accurate diagnosis could be obtained using MR textural analysis with DWI and CE-T1WI in differentiating benign from malignant soft-tissue tumors.

• Progress in Superconductivity
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• 제14권1호
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• pp.17-23
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• 2012

The heavy-fermion compound $CeRhIn_5$ is a prototypical antiferromagnet where Ce 4f moments align antiferromagnetically below 3.8 K. When doped with Hg, the antiferromagnetic transition $T_N$ initially decreases, becomes flat, and increases again with further increasing Hg concentration. Here we report pressure effects on the electrical resistivity of a 0.45 % Hg-doped $CeRhIn_5$, where $T_N$ is 3.4 K and the magnetic structure is same as that of the undoped compound with Q=(1/2, 1/2, 0.298). With increasing pressure, $T_N$ is suppressed and a superconducting state emerges. The temperature dependence of the electrical resistivity near an optimal pressure shows a power-law behavior that deviates from a $T^2$ dependence, indicating presence of abundant quantum fluctuations near the optimal pressure.

• 한국미생물·생명공학회지
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• 제49권3호
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• pp.384-390
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• 2021

A Gram-negative, aerobic, motile by gliding, and rod-shaped marine bacterium, designated CE67^T was isolated from the marine sponge Callyspongia elegans on Biyang-do in Jeju Island. The CE67^T strain grew optimally at 25℃, pH 7.5, and in the presence of 2-3% (w/v) NaCl. Phylogenetic analysis based on 16S rRNA gene sequence showed that strain CE67^T was related to the genus Aureivirga and had the highest 16S rRNA gene sequence similarity to the Aureivirga marina VIII.04^T type strain (96.3%). The primary fatty acids (>10%) of strain CE67^T were iso-C_15:0 (35.3%) and iso-C_17:0 3OH (21.8%). The polar lipid profile of strain CE67^T contained phosphatidylethanolamine, unidentified aminolipids, and unidentified lipids. The predominant menaquinone was MK-6. The DNA G+C content was 29.1 mol%. Based on the polyphasic taxonomic analysis, strain CE67^T was determined to be a representative novel species of the genus Aureivirga for which we propose the name Aureivirga callyspongiae sp. nov., whose strain type is CE67^T (=KCTC 42847^T=JCM 34566^T).

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2021년도 춘계학술대회
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• pp.474-476
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• 2021

신경 교세포에서 발생하는 가장 흔한 뇌 악성종양인 교모세포종은 조기 진단 및 치료계획 수립이 중요하다. 주로 조영제를 통해 촬영된 T1CE 영상을 통해 암의 진단이 이뤄지는데, 최근 가돌리늄 기반 조영제 주입의 위험이 보고되고 있다. 의료영상에서 새로운 영상을 합성하는 GAN 모델과 영역분할에 대한 심층신경망 모델에 대한 연구가 활발히 진행되고 있다. 본 연구에서는 교모세포종 환자의 T1CE 영상의 생성과 암의 영역분할을 동시에 학습하는 하나의 모델을 제안한다. 제안된 모델의 성능은 평균 제곱오차, 최대신호대잡음비 등의 유사성 측정을 통해 평가되어 0.002, 55dB의 평균 결과 값을 보여준다.

• 한국결정성장학회지
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• 제20권4호
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• pp.159-163
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• 2010

스컬용융법으로 큐빅지르코니아(YSZ) 단결정들($ZrO_2:Y_2O_3:Co_3O_4:CeO_2$=64:36:0.5:0~0.3mol%)을 성장시켜 $N_2$ 분위기 $1200^{\circ}C$에서 3시간 동안 열처리 하였다. 갈색의 단결정들은 각각 녹색 또는 청색으로 변화되었다. 열처리 전 후의 YSZ 단결정들은 직경 7, 두께 2 mm의 웨이퍼 또는 직경 12 mm의 라운드브릴리언트 컷으로 연마 하였다. 각 시편의 광학적 또는 구조적 특성은 UV-VIS 분광광도계와 XRD(X-ray diffraction)로 분석하였으며, $Ce^{3+}(^2F_{5/2},\;_{7/2}(4f){\rightarrow}^2T_g(5d^1))$, $Co^{2+}(^4A_2(^4F){\rightarrow}^4T_1(^4F)$ 또는 $^4T_1(^4P)$) 및 $Co^{3+}$에 의한 흡수, 이온화에너지 및 격자상수 변화를 확인하였다.

• Korean Journal of Radiology
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• 제25권4호
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• pp.363-373
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• 2024

Objective: To develop and evaluate a deep learning model for automated segmentation and detection of bone metastasis on spinal MRI. Materials and Methods: We included whole spine MRI scans of adult patients with bone metastasis: 662 MRI series from 302 patients (63.5 ± 11.5 years; male:female, 151:151) from three study centers obtained between January 2015 and August 2021 for training and internal testing (random split into 536 and 126 series, respectively) and 49 MRI series from 20 patients (65.9 ± 11.5 years; male:female, 11:9) from another center obtained between January 2018 and August 2020 for external testing. Three sagittal MRI sequences, including non-contrast T1-weighted image (T1), contrast-enhanced T1-weighted Dixon fat-only image (FO), and contrast-enhanced fat-suppressed T1-weighted image (CE), were used. Seven models trained using the 2D and 3D U-Nets were developed with different combinations (T1, FO, CE, T1 + FO, T1 + CE, FO + CE, and T1 + FO + CE). The segmentation performance was evaluated using Dice coefficient, pixel-wise recall, and pixel-wise precision. The detection performance was analyzed using per-lesion sensitivity and a free-response receiver operating characteristic curve. The performance of the model was compared with that of five radiologists using the external test set. Results: The 2D U-Net T1 + CE model exhibited superior segmentation performance in the external test compared to the other models, with a Dice coefficient of 0.699 and pixel-wise recall of 0.653. The T1 + CE model achieved per-lesion sensitivities of 0.828 (497/600) and 0.857 (150/175) for metastases in the internal and external tests, respectively. The radiologists demonstrated a mean per-lesion sensitivity of 0.746 and a mean per-lesion positive predictive value of 0.701 in the external test. Conclusion: The deep learning models proposed for automated segmentation and detection of bone metastases on spinal MRI demonstrated high diagnostic performance.

• 한국세라믹학회지
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• 제34권2호
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• pp.139-144
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• 1997

결정학적으로 T' 구조인 Nd2-xCexCuO4-$\delta$ 회토류 구리산화물 초전도체는 지금까지 매우 복잡한 미세구조를 지닌 것으로써 잘 알려져 있다. 이 구리산화물 초전도체가 초전도 특성을 띠려면, Nd3+ 이온이 Ce4+ 이온에 의해 소량 치환되고 동시에 산소환원이 필요하다. 본 연구에서는 투과전자현미경의 수렴성 전자회절(CBED)패턴을 이용하여 Nd2-xCexCuO4-$\delta$ 의 Ce 미량 첨가와 미량의 산소환원에 따른 결정구조의 전이 발생 여부에 관하여 고찰하였다. 세 가지의 서로 다른 시편 Nd2CuO3,Nd1.85Ce0.15CuO4 와Nd1.85Ce0.15CuO3.965을 고상소결에 의하여 만들어 이들 각각 시편에 대한 CBED패턴을 주사투과전자현미경(STEM)으로 관찰하였다. 그리고 실험에 의하여 얻은 이들 HOLZ선들과 컴퓨터 계산에 의해 그려진 이론적인 HOLZ선들과 비교하는 방법에 의하여 Nd1.85Ce0.15CuO4의 격자상수를 구하였다.

• 한국재료학회지
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• 제2권3호
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• pp.202-206
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• 1992

$CeO_2$를 첨가한 Y-Ba-Cu-0 초전도체를 포정반응을 포함한 준용용법으로 제조하여 미세조직과 초전도성을 관찰하였다. 첨가한 $CeO_2$는 포정반응중에 $BaCeO_3$로 변화하였으며, 이 $BaCeO_3$는 방향성 성장한 1-2-3 초전도상의 기지에 미세하게 분산된다. 초전도체의 $T_{c}$는 첨가된 $CeO_2$함량에 관계없이 90K 이상으로 매우 높았다. 이는 준용융공정을 적용함으로서 제2상물질을 초전도상으로부터 분리할 수 있었기 때문으로 사료된다.