• 한국정보통신학회논문지
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• 제26권7호
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• pp.1032-1039
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• 2022

이동통신 중계기에 사용하는 SAW(Surface Acoustic Wave) 방식의 대역통과필터를 대체할 수 있는 5G 이동통신 중계기용 군 지연 특성이 개선된 크로스 커플링 등화기 구조를 결합한 캐비티 대역통과필터를 설계하고 이를 구현하였다. 3D EM 시뮬레이션 툴 (HFSS)을 이용하여 공진 주파수, 공진기 간 결합 계수와 공진기 사이 외부 품질 계수를 계산하였고, 이를 바탕으로 메탈 캐비티 구조로 주파수대역 3500MHz~3600MHz, 대역폭 97.85MHz로 대역 양쪽 가장자리 주파수(edge)단에서 20dB 이상의 감쇄 특성을 가지도록 12차 대역 통과 필터를 제작 하였다. 설계 제작한 대역통과필터는 5G 이동통신 표준에 요구하는 군 지연 시간 조건과 인-밴드, 아웃-밴드 주파수 응답을 만족하였다.

• Clinical Pain
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• 제18권2호
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• pp.65-69
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• 2019

Objective: This study aims to evaluate the efficacy of high-voltage microcurrent therapy in patients with herniated lumbar disc (HLD) presenting radicular or back pain. Method: This is a retrospective study with 33 patients who are complaining pain with HLD findings on magnetic resonance image. Microcurrent therapy was applied to leg or paralumbar area. Treatment was conducted for seven minutes with 250~1000 uA intensity as high as the patients could tolerate via stimulating probe with roller type and the frequency was 60 Hz with a sine wave pulse. The visual analogue scale (VAS) was measured just before and after the treatment. Results: The degree of pain reduction (△VAS) was 1.6 points after treatment on average. The △VAS according to the diagnosis, stenosis, dermatome area, medication, pain site and caudal epidural block was not statistically significant. However, the △VAS according to the number of treatments (< 3, ≥ 3 times) showed a statistically significant difference (p=0.04). Conclusion: High-voltage microcurrent therapy may help reduce lumbar or lumbosacral radiating pain after the procedure. The effect was better when microcurrent was applied three times or more. This result suggests that the microcurrent would have cumulative effect on reducing radicular or back pain in patients with HLD.

• 보건행정학회지
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• 제33권3호
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• pp.325-337
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• 2023

Background: While there are many studies estimating the effects of private health insurance on various types of health care utilization, few have examined how such effects change in conjunction with important policy reforms in national health insurance (NHI). This study examined how the effect of private health insurance (supplemental and fixed cash benefit) on high-cost outpatient imaging test utilization changed following the expansion of magnetic resonance imaging (MRI) coverage in 2018, which is a key example of the NHI benefit expansion policy in recent years. Methods: Data from the 2017 and 2019 Korea Health Panel Survey, which contained information about healthcare utilization before and after the expansion of MRI coverage in 2018, were used. The incremental effect of private health insurance on high-cost outpatient imaging test utilization for each period were quantified and compared, with special attention given to the type of private health insurance. Results: While people with supplemental private health insurance were more likely to use high-cost outpatient imaging tests than those without, both before and after the expansion of MRI coverage, the incremental effect increased from 1.6% points in 2017 to 2.5% points in 2019. Conclusion: Benefit expansion in NHI does not necessarily reduce disparities in the use of health care between private health insurance subscribers and non-subscribers. The results of our study also suggest that the path through which private health insurance affects healthcare utilization may not be limited to the price mechanism alone but can be more complex.

• Korean Journal of Radiology
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• 제22권11호
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• pp.1809-1821
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• 2021

Ovarian cystadenofibroma is a benign ovarian tumor that is characterized by a consistent percentage of masses, which remain indeterminate in ultrasonography and require magnetic resonance (MR) investigation; they may mimic borderline or malignant lesions. Three main morphologic patterns, resembling different ovarian neoplasms, can be identified in cystadenofibromas: multilocular solid lesions, unilocular cystic lesions with parietal thickening, and purely cystic masses. However, a cystoadenofibroma has typical features, such as T2-weighted hypointensity associated with no restrictions in diffusion-weighted imaging (the so-called "dark-dark appearance") and progressive post-contrast enhancement (type I perfusion curve). The purpose of this study was to review the features of ovarian cystadenofibromas in MR imaging and to suggest pearls and pitfalls regarding their correct diagnosis.

• Journal of Ginseng Research
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• 제48권1호
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• pp.89-97
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• 2024

Background: Ginsenoside F2 (GF2), the protopanaxadiol-type constituent in Panax ginseng, has been reported to attenuate metabolic dysfunction-associated steatotic liver disease (MASLD). However, the mechanism of action is not fully understood. Here, this study investigates the molecular mechanism by which GF2 regulates MASLD progression through liver X receptor (LXR). Methods: To demonstrate the effect of GF2 on LXR activity, computational modeling of protein-ligand binding, Time-resolved fluorescence resonance energy transfer (TR-FRET) assay for LXR cofactor recruitment, and luciferase reporter assay were performed. LXR agonist T0901317 was used for LXR activation in hepatocytes and macrophages. MASLD was induced by high-fat diet (HFD) feeding with or without GF2 administration in WT and LXRα^-/- mice. Results: Computational modeling showed that GF2 had a high affinity with LXRα. LXRE-luciferase reporter assay with amino acid substitution at the predicted ligand binding site revealed that the S264 residue of LXRα was the crucial interaction site of GF2. TR-FRET assay demonstrated that GF2 suppressed LXRα activity by favoring the binding of corepressors to LXRα while inhibiting the accessibility of coactivators. In vitro, GF2 treatments reduced T0901317-induced fat accumulation and pro-inflammatory cytokine expression in hepatocytes and macrophages, respectively. Consistently, GF2 administration ameliorated hepatic steatohepatitis and improved glucose or insulin tolerance in WT but not in LXRα^-/- mice. Conclusion: GF2 alters the binding affinities of LXRα coregulators, thereby interrupting hepatic steatosis and inflammation in macrophages. Therefore, we propose that GF2 might be a potential therapeutic agent for the intervention in patients with MASLD.

• 대한영상의학회지
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• 제82권2호
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• pp.462-468
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• 2021

방골성 지방종(parosteal lipoma)은 모든 지방종의 약 0.3%를 차지하는 드문 유형의 지방종이다. 더구나, 골연골종(osteochondroma)과 공존하는 방골성 지방종은 극히 드물다. 이전에 골연골종과 방골성 지방종이 같이 발견된 증례들이 보고된 적 있으나, 이들은 방골성 지방종에 의해 주변 뼈에 유발된 반응성 변화로 보고되었고, 시간의 변화에 따른 종양들의 선후관계를 파악하지 못했다. 본 저자들은 6년간의 X선 사진 변화와 함께 골연골종과 연관된 방골성 지방종의 컴퓨터단층촬영, 자기공명영상, 병리학 소견에 대해 보고하고자 한다.

• 대한영상의학회지
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• 제82권1호
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• pp.267-273
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• 2021

림프종모양육아종증은 드문 B 세포형 림프세포증식병으로 추후 림프종으로 발전할 수 있는 높은 치사율을 가진 질병이다. 이는 주로 폐를 침범하며, 흔하진 않지만 뇌, 피부에도 발병할 수 있다. 소아 환자에서 림프종모양육아종증은 매우 드물게 보고된 질병으로 영상의학적 소견의 보고 또한 매우 적다. 저자들은 소아 환자에서 폐와 뇌에서 발병한 림프종모양육아종증 증례와 이의 특징적 영상의학적 소견에 대해 보고하고자 한다.

• 대한영상의학회지
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• 제82권3호
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• pp.729-736
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• 2021

다발성 원발성 악성 종양은 한 환자에서 2개 이상의 원발성 악성 종양이 각각 독립적으로 발생하는 경우를 말한다. 저자들은 78세 남자 환자에서 동시에 발생한 유방의 점액성 선암과 유방외 림프종의 증례를 경험하여 보고하고자 한다. 환자는 2개의 만져지는 덩이를 주소로 내원하여 외과적 생검을 통해 좌측 유방의 점액성 선암과 우측 서혜부의 미만성 거대 B세포 림프종을 확진하였다. 이후 수술 전 시행한 PET/CT에서 좌측 혀편도의 우연종이 발견되었고, 절제 생검을 통해 미만성 거대 B세포 림프종을 확진하였다. 유방암 환자에서 불특정한 림프절 비대가 발견되는 경우 전이성 병변으로 간주되기 쉬우나, 이 증례의 환자와 같이 고령의 환자군에서는 림프종을 감별 진단으로 함께 고려함으로써 오진 및 치료 지연을 방지할 수 있을 것이다.

• 대한영상의학회지
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• 제82권5호
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• pp.1274-1280
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• 2021

급성 괴사성 뇌병증은 드물지만 특징적인 인플루엔자 관련 뇌병증으로, 시상을 포함한 영역의 좌우 대칭의 다발성 병변을 특징으로 한다. 급성 괴사성 뇌병증의 정확한 발병 기전은 아직까지 불분명하나, 사이토카인 과분비에 의한 혈액뇌장벽의 파괴가 가장 널리 받아들여지는 가설이다. 저자들은 급격하게 진행한 10세 남아의 급성 괴사성 뇌병증 증례를 확산강조영상과 자화강조영상을 포함한 연속 자기공명영상 소견과 함께 보고하고자 한다. 연속 자기공명영상에서 나타나는 뇌병변의 시간적 변화는 임상경과 및 병태생리학적 변화와 일치되는 소견을 보였다. 본 증례는 연속 자기공명영상 소견을 통해 급성 괴사성 뇌병증 뇌병변의 발생 기전을 명확히 하였으며, 더 나아가 빠른 면역조절치료를 통해 뇌 손상의 정도를 줄일 수 있음을 시사하였다.

• Korean Journal of Radiology
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• 제1권1호
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• pp.11-18
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• 2000

Objective: To evaluate the hydrodynamic changes occurring in cerebrospinal fluid (CSF) flow in cervical spinal stenosis using the spatial modulation of magnetization (SPAMM) technique. Materials and Methods: Using the SPAMM technique, 44 patients with cervical spinal stenosis and ten healthy volunteers were investigated. The degree of cervical spinal stenosis was rated as low-, intermediate-, or high-grade. Low-grade stenosis was defined as involving no effacement of the subarachnoid space, intermediate-grade as involving effacement of this space, and high-grade as involving effacement of this space, together with compressive myelopathy. The patterns of SPAMM stripes and CSF velocity were evaluated and compared between each type of spinal stenosis and normal spine. Results: Low-grade stenosis (n = 23) revealed displacement or discontinuity of stripes, while intermediate- (n = 10) and high-grade (n = 11) showed a continuous straight band at the stenotic segment. Among low-grade cases, 12 showed wave separation during the systolic phase. Peak systolic CSF velocity at C4-5 level in these cases was lower than in volunteers (p < .05), but jet-like CSF propulsion was maintained. Among intermediate-grade cases, peak systolic velocity at C1-2 level was lower than in the volunteer group, but the difference was not significant (p > .05). In high-grade stenosis, both diastolic and systolic velocities were significantly lower (p < .05). Conclusion: Various hydrodynamic changes occurring in CSF flow in cervical spinal stenosis were demonstrated by the SPAMM technique, and this may be a useful method for evaluating CSF hydrodynamic change in cervical spinal stenosis.