• Korean Journal of Radiology
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• 제22권6호
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• pp.880-889
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• 2021

Objective: This study aimed to investigate the regional amyloid burden and myocardial deformation using T1 mapping and strain values in patients with cardiac amyloidosis (CA) according to late gadolinium enhancement (LGE) patterns. Materials and Methods: Forty patients with CA were divided into 2 groups per LGE pattern, and 15 healthy subjects were enrolled. Global and regional native T1 and T2 mapping, extracellular volume (ECV), and cardiac magnetic resonance (CMR)-feature tracking strain values were compared in an intergroup and interregional manner. Results: Of the patients with CA, 32 had diffuse global LGE (group 2), and 8 had focal patchy or no LGE (group 1). Global native T1, T2, and ECV were significantly higher in groups 1 and 2 than in the control group (native T1: 1384.4 ms vs. 1466.8 ms vs. 1230.5 ms; T2: 53.8 ms vs. 54.2 ms vs. 48.9 ms; and ECV: 36.9% vs. 51.4% vs. 26.0%, respectively; all, p < 0.001). Basal ECV (53.7%) was significantly higher than the mid and apical ECVs (50.1% and 50.0%, respectively; p < 0.001) in group 2. Basal and mid peak radial strains (PRSs) and peak circumferential strains (PCSs) were significantly lower than the apical PRS and PCS, respectively (PRS, 15.6% vs. 16.7% vs. 26.9%; and PCS, -9.7% vs. -10.9% vs. -15.0%; all, p < 0.001). Basal ECV and basal strain (2-dimensional PRS) in group 2 showed a significant negative correlation (r = -0.623, p < 0.001). Group 1 showed no regional ECV differences (basal, 37.0%; mid, 35.9%; and apical, 38.3%; p = 0.184). Conclusion: Quantitative T1 mapping parameters such as native T1 and ECV may help diagnose early CA. ECV, in particular, can reflect regional differences in the amyloid deposition in patients with advanced CA, and increased basal ECV is related to decreased basal strain. Therefore, quantitative CMR parameters may help diagnose CA and determine its severity in patients with or without LGE.

• Tribology and Lubricants
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• 제38권6호
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• pp.235-240
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• 2022

Atomically-thin 2D nanomaterials can be easily deformed and have surface corrugations which can influence the frictional characteristics of the 2D nanomaterials. Chemical vapor deposition (CVD) graphene can be grown in a wafer scale, which is suitable as a large-area surface coating film. The CVD growth involves cooling process to room temperature, and the thermal expansion coefficients mismatch between graphene and the metallic substrate induces a compressive strain in graphene, resulting in the surface corrugations such as wrinkles and atomic ripples. Such corrugations can induce the friction anisotropy of graphene, and therefore, accurate imaging of the surface corrugation is significant for better understanding about the friction anisotropy of CVD graphene. In this work, the combinatorial analysis using friction force microscopy (FFM) and transverse shear microscopy (TSM) was implemented to unveil the friction anisotropy of CVD bi-layer graphene. The periodic friction anisotropy of the wrinkles was measured following a sinusoidal curve depending on the angles between the wrinkles and the scanning tip, and the two domains were observed to have the different friction signals due to the different directions of the atomic ripples, which was confirmed by the high-resolution FFM and TSM imaging. In addition, we revealed that the atomic ripples can be easily suppressed by ironing the surface during AFM scans with an appropriate normal force. This work demonstrates that the friction anisotropy of CVD bilayer graphene is well-correlated with the corrugated structures and the local friction anisotropy induced by the atomic ripples can be controllably removed by simple AFM scans.

• 한국광학회지
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• 제29권3호
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• pp.99-103
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• 2018

동적 광단층 탄성영상법은 광 결맞음 단층촬영법을 기반으로 하여 위상차에 의해 조직의 기계적 성질 중 하나인 탄성도를 측정하기 위한 기법이다. 광 결맞음 단층촬영법은 마이켈슨 간섭계를 기반으로 한 비침습적 고해상도 단면 촬영기법이다. 본 논문에서는 광단층 탄성영상법을 생체 조직에 적용하기 전에 실행가능성을 판단하고자 강도를 쉽게 구분할 수 있는 지우개, 스펀지, 샤프심으로 샘플을 제작하여 실험을 진행하였다. 샘플에 사인파의 일정한 진동자극을 가하기 위해 압전액추에이터를 샘플의 아래쪽에 위치시켰으며 위쪽에서 광 결맞음 단층촬영법으로 스캔하였다. 깊이마다 횡방향에 대한 변형속도를 힐버트 변환하여 포락선을 검출한 후 포락선의 높낮이를 색깔로 표현하여 이미지 상에서 샘플 내의 상대적인 강도를 비교할 수 있었다. 또한, 샘플단과 참조단 사이의 간섭을 이용하는 것보다 샘플단 내의 자기간섭을 이용할 경우 변형속도 계산에 있어 장점이 있음을 제시하였다.

• The Korean Journal of Physiology and Pharmacology
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• 제21권6호
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• pp.643-650
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• 2017

Vascular dementia (VaD) is a group of heterogeneous diseases with the common feature of cerebral hypoperfusion. To identify key factors contributing to VaD pathophysiology, we performed a detailed comparison of Wistar and Sprague-Dawley (SD) rats subjected to permanent bilateral common carotid artery occlusion (BCCAo). Eight-week old male Wistar and SD rats underwent BCCAo, followed by a reference memory test using a five-radial arm maze with tactile cues. Continuous monitoring of cerebral blood flow (CBF) was performed with a laser Doppler perfusion imaging (LDPI) system. A separate cohort of animals was sacrificed for evaluation of the brain vasculature and white matter damage after BCCAo. We found reference memory impairment in Wistar rats, but not in SD rats. Moreover, our LDPI system revealed that Wistar rats had significant hypoperfusion in the brain region supplied by the posterior cerebral artery (PCA). Furthermore, Wistar rats showed more profound CBF reduction in the forebrain region than did SD rats. Post-mortem analysis of brain vasculature demonstrated greater PCA plasticity at all time points after BCCAo in Wistar rats. Finally, we confirmed white matter rarefaction that was only observed in Wistar rats. Our studies show a comprehensive and dynamic CBF status after BCCAo in Wistar rats in addition to severe PCA dolichoectasia, which correlated well with white matter lesion and memory decline.

• 한국음향학회지
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• 제24권5호
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• pp.282-293
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• 2005

음향 탄성영상법은 외부 진동을 조직에 인가하고 조직 운동을 측정함으로써 조직의 탄성을 영상화하는 초음파영상기법이다. 본 논문에서는 음향 탄성영상법에서 표면 진동자에 의해 연조직 내에 파동이 발생되는 특성과 모드패턴이암과 같은 병변 검출에 미치는 영향을 조사였다. 이를 위해 반공간, 두께가 일정한 무한평판, 그리고 유한 크기 조직에서 발생된 진동패턴을 이론과 유한요소법으로 계산하고 분석하였다. 유한 너비 진동원에 의해 조직에는 특정한 방향으로 강하게 전달되는 횡파가 발생하였으며, 그 특성은 진동자 너비, 주파수 및 진동자로부터의 거리에 의존하였다. 유한 크기 조직에서 병변의 검출가능성은 변위영상에서는 조직내 모드패턴에 큰 영향을 받았으며, 이에 비해 변형률영상에서는 모드패턴에 덜 민감하고 검출가능성도 아주 높은 것으로 나타났다.

• Journal of Cardiovascular Imaging
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• 제31권4호
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• pp.200-206
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• 2023

BACKGROUND: Right ventricular (RV) dysfunction is a significant risk of major adverse cardiac events in patients with acute heart failure (AHF). In this study, we evaluated RV-pulmonary artery (PA) coupling, assessed by tricuspid annular plane systolic excursion (TAPSE)/pulmonary artery systolic pressure (PASP) and assessed its prognostic significance, in AHF patients. METHODS: We measured the TAPSE/PASP ratio and analyzed its correlations with other echocardiographic parameters. Additionally, we assessed its prognostic role in AHF patients. RESULTS: A total of 1147 patients were included in the analysis (575 men, aged 70.81 ± 13.56 years). TAPSE/PASP ratio exhibited significant correlations with left ventricular (LV) ejection fraction(r = 0.243, p < 0.001), left atrial (LA) diameter(r = -0.320, p < 0.001), left atrial global longitudinal strain (LAGLS, r = 0.496, p < 0.001), mitral E/E' ratio(r = -0.337, p < 0.001), and right ventricular fractional area change (RVFAC, r = 0.496, p < 0.001). During the median follow-up duration of 29.0 months, a total of 387 patients (33.7%) died. In the univariate analysis, PASP, TAPSE, and TAPSE/PASP ratio were significant predictors of mortality. After the multivariate analysis, TAPSE/PASP ratio remained a statistically significant parameter for all-cause mortality (hazard ratio [HR], 0.453; p = 0.037) after adjusting for other parameters. In the receiver operating curve analysis, the optimal cut-off level of TAPSE/PASP ratio for predicting mortality was 0.33 (area under the curve = 0.576, p < 0.001), with a sensitivity of 65% and a specificity of 47%. TAPSE/PASP ratio < 0.33 was associated with an increased risk of mortality after adjusting for other variables (HR, 1.306; p = 0.025). CONCLUSIONS: In AHF patients, TAPSE/PASP ratio demonstrated significant associations with RVFAC, LA diameter and LAGLS. Moreover, a decreased TAPSE/PASP ratio < 0.33 was identified as a poor prognostic factor for mortality.

• Nuclear Medicine and Molecular Imaging
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• 제40권4호
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• pp.211-217
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• 2006

재조합된 scFv lym-1의 세포결합 실험에서 높은 면역반응성을 보였으며, 비특이 반응에서 모항체인 IgG lym-1에 의해 결합이 억제됨을 확인하였고, 동물 영상을 통해 IgG보다 분자랑이 작은 scFv lym-1 항체가 빠른 체내대사율과 종양섭취율을 보여 방사면역진단에 유용할 것으로 보여진다.

• Journal of Microbiology and Biotechnology
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• 제19권4호
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• pp.403-408
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• 2009

A number of bifidobacterial species of human origin were screened for the presence of cryptic plasmids. One strain, Bifidobacterium longum FI10564, harbored plasmids of approximately 2.2 kb, 3.6 kb, and 4.9 kb in size. The smallest plasmid, pFI2576(2,197 bp), was studied in detail and its complete nucleotide sequence was determined. Computer-assisted analysis of this novel plasmid(G+C content 62%) identified 9 putative open reading frames(orfs), 3 of which were shown to be probable genes. These putative genes are arranged in an operon-like structure, in which the overlapping orfs 1 and 2 encode putative Rep proteins and are highly homologous to the rep genes of the B. longum plasmid pMBI(1,847 bp). The mechanism of replication of pFI2576 was investigated using Southern blot analysis of whole cell lysates, with and without S1 nuclease treatment, and atomic force microscopy(AFM). The results indicate that pFI2576 is likely to use the theta mode of replication.

• Clinical Pain
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• 제18권2호
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• pp.107-110
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• 2019

Flexor carpi radialis (FCR) muscle is located in the forearm anteriorly that runs through a synovial fibro-osseous tunnel in the forearm. We described a case of FCR tendon rupture due to repetitive overuse injury. A 55-year-old man, right-hand dominant, presented with right forearm pain and swelling which started 3 days ago while playing amateur golf. Focal tenderness and bruising over volo-ulnar region of the right forearm were examined. Plain radiographs showed soft tissue edema around lesion area and no detectable fracture. Ultrasonography showed multiple hypoechoic lesions suspected as hematoma of the flexor muscle group. After done magnetic resonance imaging, he was diagnosed with rupture of FCR tendon at proximal origin and strain of flexor digitorum superficialis and palmaris longus muscle. He received compressive dressing and restriction of wrist range of motion for three weeks. Two months later, remaining traces of lesions were observed at the follow-up ultrasonography and the pain disappeared.

• Journal of Acupuncture Research
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• 제27권4호
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• pp.19-28
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• 2010

Objectives : To demonstrate the need for differential diagnosis between discogenic pain and lumbar sprain and strain in acute low-back pain patients. Methods : Outpatients who made their first visits during May 1, 2009 to Oct. 30, 2009(n=53) were examined by history taking, physical examination, X-rays, and CT imaging. Disorders found on lumbosacral spine X-ray cuts and those on lumbosacral spine CT images were separately recorded. The relationship between treatment period, disc space narrowing and disc degeneration on X-rays, and HIVD on CT images was examined. Results : 1. Correlation between disc space narrowing on X-rays and HIVD found on CT images was analyzed. 21(72.41%) out of 29 patients having disc space narrowing on X-rays and HIVD on CT at the same level required treatment for over 8 weeks. 2. 2(50%) out of 4 Lawrence classification grade I patients, 8(66.67%) out of 12 grade II patients, and 14(70%) out of 20 grade III patients needed treatment for over 8 weeks. Conclusions : Disc space narrowing on X-ray and HIVD on CT at the same level, or disc space narrowing and disc degeneration on X-ray image alone indicate a tendency for treatment periods over 8 weeks, which is longer than the conventional treatment period for lumbar strain and sprain.