• Journal of the Korea Institute of Information and Communication Engineering
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• v.21 no.5
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• pp.861-868
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• 2017

Near band infrared imaging technique has adopted for imaging EL2 and shallow level distributions in undoped semi-insulating LEC GaAs. This technique, which relies on the mapping of near bandgap infrared transmission, is both rapid and non-destructive. Until now no quantitative analysis has been reported for near band edge region which gives the reverse contrast on EL2 absorption images. This paper presents the spectral, spatial and temperature dependence of photoquenching forward and inverse mechanism in the band edge domain for cells and walls and for direct and inverted contrast conditions during transitory regimes. The difference in the threshold for the EL2w and EL2b defects could be attributed to the contribution of a different electrical assistance due to a different species of impurities. Quantitative analysis results show an increased density of EL2w and a small reduction of EL2b in the region of the walls where there is a high density of dislocations.

• The Korean Journal of Nuclear Medicine
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• v.32 no.4
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• pp.325-331
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• 1998

Purpose: We evaluated the importance of redistribution and 24 hour reinjection images in T1-201 SPECT assessment of myocardial viability after acute myocardial infarction (AMI). Materials and Methods: We performed dipyridamole stress-4 hour redistribution-24 hour reinjection T1-201 SPECT in 43 patients with recent AMI (4-16 days). The myocardium was divided into 16 segments and perfusion grade was measured visually with 4 point score from 0 to 3 (absent uptake to normal uptake). A perfusion defect with stress score 2 was considered moderate. A defect was considered severe if the stress score was 0 or 1 (absent uptake or severe perfusion decrease). Moderate defect on stress image were considered viable and segments with severe defect were considered viable if they showed improvement of 1 score or more on redistribution or reinjection images. We compared the results of viability assessment in stress-redistribution and stress-reinjection images. Results: On visual analysis, 344 of 688 segments (50%) had abnormal perfusion. Fifty two (15%) had moderate perfusion defects and 292 (85%) had severe perfusion defects on stress image. Of 292 severe stress defects, 53 were irreversible on redistribution and reversible on reinjection images, and 15 were reversible on redistribution and irreversible on reinjection images. Two hundred twenty four of 292 segments (76.7%) showed concordant results on stress-redistribution and stress-reinjection images. Therefore 24 hour reinjection image changed viability status from necrotic to viable in 53 segments of 292 severe stress defect (18%). However, myocardial viability was underestimated in only 5% (15/292) of severe defects by 24 hour reinjection. Conclusion: The 24 hour reinjection imaging is useful in the assessment of myocardial viability. It is more sensitive than 4 hour redistribution imaging. However, both redistribution and reinjection images are needed since they complement each other.

• Journal of Chest Surgery
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• v.43 no.1
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• pp.25-32
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• 2010

Background: Patients with vascular diseases commonly have coronary artery disease and associated cardiac problems. Therefore, their underlying heart diseases may be induced or exacerbated after vascular surgery. The effectiveness of SPECT imaging, which is a relatively simple and non-invasive imaging modality, for assessing these underlying heart diseases is still controversial. This study was performed to evaluate the clinical effect of tests and treatment based on SPECT imaging prior to vascular surgery on the development of post-operation cardiac complications. Material and Method: Sixty three patients who were treated at Inje University Pusan Paik Hospital between April 2004 and September 2007 and who underwent adenosine infusion technetium-99m (Tc-99m) tetrofosmin SPECT imaging prior to vascular surgery were selected for this study and we retrospectively reviewed their records. Result: The sensitivity and specificity of detecting a perfusion defect on SPECT to predict the development of cardiac complications was relatively low at 41.2% and 52.2%, respectively. However when coronary angiographies were done on the patients with abnormal SPECT and this was followed by aggressive treatment such as coronary artery intervention and coronary artery bypass grafting based on the angiography results, there was a tendency for lower cardiac complication rates. Conclusion: SPECT imaging shows low effectiveness as a screening test for predicting cardiac complications after vascular surgery.

• Imaging Science in Dentistry
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• v.37 no.4
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• pp.221-223
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• 2007

The radiographic diagnosis of typical Stafne bone cavity could be done easily with cyst-like round or oval radiolucency near the angle of the mandible, under mandibular canal with or without involving mandibular base, and no symptoms. However there are some atypical cases suggesting possible variations of this entity. We report a quite unusual case, where Stafne bone cavity was lastly included in the differential diagnosis list. Histological examination of salivary gland tissues confirmed the final diagnosis.

• Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
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• 2004.04a
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• pp.251-257
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• 2004

The Electro-Optical Camera(EOC) image of the first Korea Multi-Purpose Satellitel(KOMPSAT-1) has both high resolution and convenient acquisition of research data, but on the other hand it has a defect of one band image. Fortunately, the multispectral Moderate Resolution Imaging Spectroradiometer (MODIS) image data are receiving every day at the Korea Aerospace Research Institute (KARI). Therefore, this paper performed an effective merging for survey of reclaimed land using the high-resolution (6.6m) KOMPSAT-1 EOC image and the multispectral MODIS image data. According this paper prepared map of reclaimed lands in Western Coast of North Korea as quantitative(position and form) survey of reclaimed lands of North Korea using merged image. The use of KOPSAT-1 EOC image and MODIS images was found to be economical such using of large scale areas as reclaimed land or according easy to collect information and such north korea as inaccessible areas like as receiving every day.

• Imaging Science in Dentistry
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• v.34 no.1
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• pp.55-59
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• 2004

Cleidocranial dysplasia is a rare and autosomal dominent disorder characterized by aplasia or hypoplasia of the clavicles, an open fontanelle, dental abnormalities, and short stature, A 17-year-old female who presented with short stature and subsequent delay in eruption of permanent teeth is described. she showed the abnormal hypermobility of the shoulder, ocular hypertelorism and concave nasal bridge. Radiographs revealed the underdeveloped maxilla, defect of the cranium in the fontanelle region, and aplasia of the clavicles. Characteristically, panoramic view revealed near parallel-sided borders of the ascending ramus and downward curvature of the zygomatic arch with hypoplasia. The prolonged retention of deciduous teeth with delayed eruption of permanent teeth and multiple embedded supernumerary teeth were striking. Radiographic and clinical investigations revealed Cleidocranial dysplasia.

• Korean Journal of Veterinary Research
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• v.51 no.4
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• pp.319-323
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• 2011

A 12-year-old spayed female Yorkshire terrier dog was presented with two-weeks history of lethargy, mental dullness and polydipsia. Neurologic examination revealed proprioceptive defect of all limbs and loss of swallowing gag reflex. The dog revealed persistent dehydration, hypernatremia, hyperosmolarity and hyposthenuria. On magnetic resornance imaging (MRI), the mass were heterogeneous signality on T1 weighted images, hyperintense signality on T2 weighted image with contrast enhancement on hypothalamohypophyseal lesion. Based on these findings, the dog was suspected as having pituitary gland tumor. Through water deprivation test and response to desmopressin acetate (1-deamino-8-D-arginine, DDAVP), this case was diagnosed by central diabetes insipidus (CDI). This paper reports the clinical sign, MRI, response to the exogenous antidiuretic hormone of CDI due to suspected pituitary tumor in a dog and DDAVP administration was evaluated effective therapy to correct hypernatremia induced by CDI.

• Proceedings of the Korean Vacuum Society Conference
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• 2016.02a
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• pp.140.2-140.2
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• 2016

Despite the growing interest in GeTe as a archetypal displacive ferroelectric material as well as the basis of related materials used in data-storage applications, atom-resolved study of single crystalline GeTe surface been lacking. Using low temperature scanning tunneling microscopy (STM) and spectroscopy (STS), we investigated as-cleaved and annealed surfaces of GeTe. We found that as-cleaved GeTe(111) surface is composed of at least two kinds of terraces at 78 K. While two terraces show metallic characteristics, they also exhibit distinctive I-V spectra and imaging conditions, with each being attributed to Ge-terminated, and Te-terminated surfaces respectively. GeTe(111) surfaces annealed at moderately elevated temperature introduces intricate networks of extended defect structures. We will present these data and discuss the role of vacancies in the formation of these structures.

• Imaging Science in Dentistry
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• v.46 no.4
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• pp.229-237
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• 2016

Purpose: The aim of this article is to review a group of lesions associated with periodontal ligament (PDL) widening. Materials and Methods: An electronic search was performed using specialized databases such as Google Scholar, PubMed, PubMed Central, Science Direct, and Scopus to find relevant studies by using keywords such as "periodontium", "periodontal ligament", "periodontal ligament space", "widened periodontal ligament", and "periodontal ligament widening". Results: Out of nearly 200 articles, about 60 were broadly relevant to the topic. Ultimately, 47 articles closely related to the topic of interest were reviewed. When the relevant data were compiled, the following 10 entities were identified: occlusal/orthodontic trauma, periodontal disease/periodontitis, pulpo-periapical lesions, osteosarcoma, chondrosarcoma, non-Hodgkin lymphoma, progressive systemic sclerosis, radiation-induced bone defect, bisphosphonate-related osteonecrosis, and osteomyelitis. Conclusion: Although PDL widening may be encountered by many dentists during their routine daily procedures, the clinician should consider some serious related conditions as well.

• Applied Microscopy
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• v.42 no.3
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• pp.164-173
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• 2012

The relaxor ferroelectric feature in lead-free perovskite oxides, where the dipoles are randomly oriented and they can be feasibly aligned parallel to the external bias, is attracting lots of attention in the field of piezoelectric materials science, since it is one of candidates to replace the toxic lead-based materials that are still being commercially used. However, the origin of relaxor characteristic and its related atomic structure are still ambiguous. In this study, $Na_{1/2}Bi_{1/2}TiO_3$, chosen as a model relaxor system, was found to exhibit a cationic-disordered atomic structure; and furthermore the nonpolar atomic structure and its related oxygen tilting were ascertained via annular bright field imaging skill. We also found that this cationic disordering gives rise to the local formation of atomic vacancies.