• Bulletin of the Korean Chemical Society
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• v.31 no.5
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• pp.1177-1181
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• 2010

The synthesis and characterization of gold nanoparticles coated by Gd-chelate (GdL@Au) is described, where L is a conjugate of DTPA (DTPA = diethylenetriamine-N,N,N',N",N"-pentaacetic acid) and 4-aminothiophenol. These particles are obtained by the replacement of citrate from the gold nanoparticle surfaces with gadolinium chelate (GdL). The average size of GdL@Au is 12 nm with a loading of GdL reaching up to $1.4{\times}10^3$ per particles, and they demonstrate very high r1 relaxivity (${\sim}10^4mM^{-1}s^{-1}$) and the r1 relaxivity per [Gd] is as high as $10mM^{-1}s{-1}$. Here, we also describe the use of bimodality of this contrast agent (CA) as a highly efficient CT contrast agent based on gold nanoparticles (GNPs) that overcome the limitations of iodine based contrast agent. The MTT assay performed on this CAs reveals the cytotoxicity as low as that for Omniscan$^{(R)}$ in the concentration range required to obtain intensity enhancement in the in vivo MRI study.

• Progress in Superconductivity and Cryogenics
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• v.18 no.3
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• pp.6-9
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• 2016

The enhancement of mechanical properties of coated conductor (CC) tapes in practical application are usually achieved by reinforcing through lamination or electroplating metal layers on either sides of the CC tape. Mechanical or electromechanical properties of the CC tapes have been largely affected by the lamination structure under various loading modes such as tension, bending or even cyclic. In this study, the influence of brass laminate volume fraction on electromechanical properties of RCE-DR processed Gadolinium-barium-copper-oxide (GdBCO) CC tapes was investigated. The samples used were composed of single-side and both-side laminate of brass layer to the Cu-stabilized CC tape and their $I_c$ behaviors were compared to those of the Cu-stabilized CC tape without external lamination. The stress/strain dependences of $I_c$ in laminated CC tapes under uniaxial tension were analyzed and the irreversible stress/strain limits were determined. As a result, the increase of brass laminate volume fraction initially increased the irreversible strain limit and became gradual. The corresponding irreversible stress limit, however, showed no difference even though the brass laminate volume fraction increased to 3.4. But the irreversible load limit linearly increased with the brass laminate volume fraction.

• Journal of radiological science and technology
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• v.11 no.1
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• pp.17-23
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• 1988

As the reutilizing method of exhausted screen, authors used it as a filter and compared with the aluminium filtration. The results are as followed; 1. One sheet of gadolinium front screen has the same radiation absorption as $2.8{\sim}3.3\;mm$ Al equivalent and regular tungsten screen $2.3{\sim}2.7mm$ Al. 2. HVL after Gd-screen filtration was less than the values after aluminium and tungsten-screen filtration. And, image definition with Gd-screen filtration was better than other two cases. Ana surface dose to produce a same film density was more than other two cases. It will be very useful to apply, Gd-screen filter in clinics as it has no deficiency of image quality.

• Proceedings of the Korean Society of Medical Physics Conference
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• 2003.09a
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• pp.72-72
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• 2003

Purpose: To prove feasibility of proton chemical shift imaging (lH CSI) during stereotactic procedure, authors performed IH CSI in combination with a stereotactic headframe and selected targets according to local metabolic information, evaluated the pathologic results. Methods: The 1H CSI directed stereotactic biopsy was performed in five patients. 1H CSI was performed before conventional stereotactic MRI with gadolinium enhancement for stereotactic coordinates. The metabolite images expressed as integral ratios, Cho/Cr and Lac/Cr, were displayed in different colors. The stereotactic target coordinates were correlated with the coordinates from the 1H CSI images. Results: The final pathologic results obtained were concordant with the local metabolic information from 1H CSI. We believe that 1H CSI-directed stereotatic biopsy has the potential to significantly improve the accuracy of stereotactic biopsy targeting. Conclusions : Metabolic signals derived from 1H CSI could give us more direct clues for stereotactic target selection during the subsequent conventional stereotactic MR imaging. 1H CSI was feasible with the stereotatic headframe in place. The final pathologic results obtained were concordant with the local metabolic information from 1H CSI. Acknowledgement: This study was supported by a grant of the Center for Functional and Metabolic Imaging Technology, Ministry of Health & Welfare, Republic of Korea (02-PJ3-PG6-EV07-0002).

• Biomedical Science Letters
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• v.10 no.2
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• pp.115-120
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• 2004

To investigate the correlation between the magnetic resonance imaging (MRI) of cerebral fat embolism that is induced by injecting oleic acid into 10 cats, and a pathologic diagnosis. Using a microcatheter, 30 ${mu}ell$ of oleic acid was injected into the internal carotid artery of 10 cats. MR T2-weighted image (T2WI), diffusion-weighted image (DWI) and Gadolinium-enhanced T1-weighted image (Gd-enhanced T1WI) were obtained after 30 minutes and 2 hours of embolization. After 30 minutes of the embolization, lesions of very high signal intensity were detected by T2WI in 6 cats, and of slightly high signal intensity in 2 cats; in the remaining 2 cats, signal intensity was normal. DWI showed lesions of very high intensity in 9 cats and of slightly high intensity in one cat. According to the findings of light microscopic examination, infarcted lesions mainly involved the gray matter, but also some white matter. A magnetic resonance imaging diagnosis for cerebral fat embolism that was induced by oleic acid through the internal carotid artery in cats showed high signal intensity on the T2WI and the DWI within an initial 2 hours, and with a well enhancement on the Gd-enhanced T1WI. Considering cellular edema, cerebrovascular injury and extracellular space widening, we assumed pathologically that cytotoxic and vasogenic edema exists at the same time.

• Journal of Korean Neurosurgical Society
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• v.48 no.2
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• pp.181-184
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• 2010

A case of idiopathic hypertrophic cranial pachymeningitis (IHCP) misdiagnosed as an acute subdural hematoma is reported. A 37-year-old male patient presented with headache following head trauma 2 weeks earlier. Computerized tomography showed a diffuse high-density lesion along the left tentorium and falx cerebri. Initial chest X-rays revealed a small mass in the right upper lobe with right lower pleural thickening, which suggested lung cancer, such as an adenoma or mediastinal metastasis. During conservative treatment under the diagnosis of a subdural hematoma, left cranial nerve palsies were developed (3rd and 6th), followed by scleritis and uveitis involving both eyes. Magnetic resonance imaging (MRI) revealed an unusual tentorium-falx enhancement on gadolinium-enhanced T1-weighted images. Non-specific chronic inflammation of the pachymeninges was noticed on histopathologic examination following an open biopsy. Systemic steroid treatment was initiated, resulting in dramatic improvement of symptoms. A follow-up brain MRI showed total resolution of the lesion 2 months after steroid treatment. IHCP should be included in the differential diagnosis of subtentorial-enhancing lesions.

• Journal of Korean Neurosurgical Society
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• v.49 no.6
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• pp.363-366
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• 2011

Cerebellar pilocytic astrocytomas (PAs) are benign gliomas predominantly found in the pediatric population. Intracranial hemorrhages are extremely rare in initial presentations of cerebellar PAs. There are no reports in the medical literature of adult cerebellar PA cases presenting with intratumoral hemorrhage. We report 2 cases of adult cerebellar pilocytic astrocytomas with intratumoral hemorrhage. The first case is a 37-year-old woman presenting with severe headache, nausea, and vomitting. Computed tomography demonstrated an acute hemorrhage adjacent to the right cerebellar hemisphere and hydrocephalus. Magnetic resonance imaging (MRI) revealed a cerebellar vermian tumor with the hemorrhage as a mixed isoin-tense area in the T2-weighted image, and as a mixed hyperintense area in the contrast-enhanced T1-weighted image. The second case is a 53-year-old man presenting with headache for 3 weeks. MRI revealed a cerebellar hemispheric tumor with the hemorrhage as a mixed hyperintense area. It had a cystic mass with a heterogeneous enhanced mural nodule in the gadolinium-enhanced T1-weighted image and a fluid-fluid level within the cyst in the T2-weighted image. Both of them underwent radical resections of their respective lesions. Histological examination of the specimens revealed typical astrocytoma, including a hemorrhagic portion. Both patients recovered postoperatively and continue to do well at present. The medical literature on hemorrhagic cerebellar PAs is also reviewed.

• Journal of Korean Neurosurgical Society
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• v.57 no.2
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• pp.135-139
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• 2015

Spinal neurenteric cysts are uncommon congenital lesions, furthermore solitary neurenteric cysts of the upper cervical spine are very rare. A 15-year-old boy having an intraspinal neurenteric cyst located at cervical spine presented with symptoms of neck pain and both shoulders pain for 2 months. Cervical spine magnetic resonance (MR) imaging demonstrated an intradural extramedullary cystic mass at the C1-3 level without enhancement after gadolinium injection. There was no associated malformation on the MR imaging, computed tomography, and radiography. Hemilaminectomy at the C1-3 levels was performed and the lesion was completely removed through a posterior approach. Histological examination showed the cystic wall lined with ciliated pseudostratified columnar epithelium containing mucinous contents. Neurenteric cyst should be considered in the diagnosis of spinal solitary cystic mass.

• Journal of the Korean Vacuum Society
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• v.12 no.1
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• pp.64-69
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• 2003

Using a high fewer electron beam gun (max. power 20 kW), Gadolinium (Gd, atomic number 64) metal was melted and the temperature distribution of melted surface was measured. With proper optical filters and the adjustment of aperture of lens, the radiation of melted surface was received by a ccd camera and its signal transferred to a computer. The real time monitoring of melted surface with a variation of electron beam Power was Possible and stable operation of electron beam was achieved. It was found that the max. temperature measured by a ccd camera with an assumption of blackbody radiation of melted Gd surface and adaption of Planet's law was above 100~$200^{\circ}C$ compared to that measured by a pyrometer in the same e-beam power.

• Journal of Korean Neurosurgical Society
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• v.52 no.2
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• pp.156-158
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• 2012

Intervertebral intradural lumbar disc herniation (ILDH) is a quite rare pathology, and isolated intradural lumbar disc herniation is even more rare. Magnetic resonance imaging (MRI) may not be able to reveal ILDHs, especially if MRI findings show an intact lumbar disc annulus and posterior longitudinal ligament. Here, we present an exceedingly rare case of an isolated IDLH that we initially misidentified as a spinal intradural tumor, in a 54-year-old man hospitalized with a 2-month history of back pain and right sciatica. Neurologic examination revealed a positive straight leg raise test on the right side, but he presented no other sensory, motor, or sphincter disturbances. A gadolinium-enhanced MRI revealed what we believed to be an intradural extramedullary tumor compressing the cauda equina leftward in the thecal sac, at the L2 vertebral level. The patient underwent total L2 laminectomy, and we extirpated the intradural mass under microscopic guidance. Histologic examination of the mass revealed a degenerated nucleus pulposus.