• Journal of Korean Neurosurgical Society
• /
• v.29 no.8
• /
• pp.1098-1102
• /
• 2000

Pituitary abscess is a very rare disorder, since antibiotics therapy has become widely available. Clinically and radiologically, the preoperative diagnosis of pituitary abscess is difficult because of its features which may be identical to those of any space-occupying lesions of the sella turcica. A combination of clinical features, such as meningitis, paranasal sinusitis and panhypopituitarism with intrasellar cystic lesion with homogeneous ring enhancement on computed tomography or magnetic resonance image should raise the suspicion of a pituitary abscess. Drainage of the abscess through trans-sphenoidal approach, appropriate antibiotics therapy, endocrine assessment and hormonal replacement should bring complete recovery to the patient. The authors review the literature and report two cases of primary pituitary abscess.

• Transactions of the Korean Society for Noise and Vibration Engineering
• /
• v.15 no.6 s.99
• /
• pp.706-711
• /
• 2005

Torsional oscillations of a system incorporating a Hooke's joint are investigated by studying a simple similar nonlinear 2-degree-of-freedom model, which has linear and quadratic nonlinear parametric excitations. The simple system is identified to have the possibilities of primary, sub harmonic and combination resonances. The case of simultaneous primary and combination resonances is selected for perturbation analysis to have the reduced amplitude-equations of motion. The same procedure is applied to the system incorporating a Hooke's joint.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.66 no.4
• /
• pp.636-642
• /
• 2017

Recently, new power devices, SiC and GaN FETs, are commercialized. They are expected to change power electronics environments. They will raise operating frequencies of power electronic equipments. Accordingly, design method will be changed greatly. In this paper, an 1 MHz resonant converter with fully compensated coreless isolation transformer is proposed, where the primary voltage is proportional to the secondary current and the primary current to the secondary voltage. 30 W prototype is constructed and tested, and its usefulness is verified.

• Journal of Yeungnam Medical Science
• /
• v.29 no.1
• /
• pp.54-57
• /
• 2012

Neurilemmoma is a benign and slowly growing neurogenic tumor. Intrathoracic neurilemmoma often develops in the chest wall and posterior mediastinum, but endobronchial neurilemmoma is extremely rare. The diagnosis of endobronchial neurilemmoma with preoperative imaging findings is challenging and is usually made via postoperative pathological examination. These authors encountered a case of primary endobronchial neurilemmoma in a 52-year-old woman who had no symptoms. A $3.0{\times}2.6$ cm mass in the right lower lobe projecting into the mediobasal segmental bronchus was shown in the results of the contrast-enhanced computed tomography (CT) and magnetic resonance imaging (MRI) of the chest. Benign neurilemmoma was confirmed via bronchoscopic biopsy, and surgical resection (sleeve bronchial excision and end-to-end anastomosis) was performed.

• Proceedings of the KIPE Conference
• /
• 2004.11a
• /
• pp.45-48
• /
• 2004

To improve the efficiency characteristics in the resonant converter using the contact-less power supply with the large air-gap and the long primary winding, this paper suggests the three-level series-parallel resonant converter(SPRC). The voltage gain characteristics of the proposed converter have the unit gain in a resonance frequency point of the series and parallel, and input voltage and current in the primary of SPRC are always In phase for the all equivalent load resistance because of the parallel resonant tank of the high impedance. The results are verified on the simulation based on the theoretical analysis and the 4kW experimental prototype.

• Proceedings of the KIEE Conference
• /
• 2003.11a
• /
• pp.31-33
• /
• 2003

Power system restoration following a partial or complete blackout starts with energizing of primary transmission lines. Because system changed rapidly during early restoration process, transformer energization and load pickup is executed to maintain the power system stability. However unexpected problem such as harmonic overvoltage may be arisen during energizing transformer. The reason of harmonic overvoltage is known as transformer saturation and magnetizing in-rush current and so on, but it is difficult to estimate the condition of occurrence. This paper describes the analysis of the harmonic overvoltage while unloaded transformer is energized using PSCAD/EMTDC.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 1996.10a
• /
• pp.282-287
• /
• 1996

The non-linear torsional vibrations of the propulsion shafting system with viscous damper are considered. The motion is modeled by non-linear differential equations of second order. the equivalent system is modeled by two mass softening system with Duffing's oscillator. The steady state response of a equivalent system is analyzed for primary resonance only. Harmonic balance method as a non-linear vibration analysis technique is used. Jump phenomena are explained. The primary unstable region obtained by the Mathieu equation is investigated. Both theoretical and measured results of the propulsion shafting system are compared with and evaluated. As a result of comparisons with both data, it was confirmed that Duffing's oscillator can be used as a analysis method in the modeling of the propulsion shafting system attached viscous damper with non-linear stiffness.

• Journal of Korean Neurosurgical Society
• /
• v.60 no.1
• /
• pp.98-101
• /
• 2017

We report a case of primary intracranial malignant melanoma (PIMM) with extracranial metastases. The patient was an 82-year-old woman diagnosed with PIMM under the left cerebellar tentorium. We performed a tumor resection followed by gamma knife surgery. An magnetic resonance imaging at 11 months after surgery showed a local intracranial recurrence. At 12 months, vertebral metastasis was suspected, and 2-[fluorine-18]-fluoro-2-deoxy-D-glucose positron emission tomography/computed tomography (FDG-PET/CT) showed multiple extracranial metastases. She died at 13 months after surgery. Although extracranial metastases of PIMM are extremely rare, we should carefully follow up extracranial metastases together with intracranial ones, especially by FDG-PET/CT, even at an early asymptomatic stage.

• Pediatric Gastroenterology, Hepatology & Nutrition
• /
• v.24 no.5
• /
• pp.413-422
• /
• 2021

Intestinal lymphangiectasia is a rare disease which is causing protein-losing enteropathy. Treatment of intestinal lymphangiectasia can be a challenge for clinicians because of the lack of specific guidelines regarding pharmacological indications. We sought to introduce a diagnostic approach and suggest guidelines for treatment. After exclusion of secondary intestinal lymphangiectasia, magnetic resonance lymphangiography is a promising tool for the assessment of abnormal lymphatic lesions in primary intestinal lymphangiectasia. Determining the extent of the lesion provides direction for treatment options. Focal short-segment intestinal lymphangiectasia can be treated via intestinal resection or radiologic embolization after dietary therapy failure. Diffuse intestinal lymphangiectasia and extensive lymphangiectasia should be treated with several drugs with a full understanding of their mechanisms.

• Korean Journal of Radiology
• /
• v.20 no.6
• /
• pp.909-915
• /
• 2019

The Korean Society of Radiology and the National Evidence-based Healthcare Collaborating Agency developed a primary imaging test for suspected traumatic thoracolumbar spine injury. This guideline was developed using an adaptation process involving collaboration between the development committee and the working group. The development committee, consisting of research methodology experts, established the overall plan and provided support on research methodology. The working group, composed of radiologists with expertise in musculoskeletal imaging, wrote the recommendation. The guidelines recommend that thoracolumbar spine computed tomography without intravenous contrast enhancement be the first-line imaging modality for diagnosing traumatic thoracolumbar spine injury in adults.