• The Korean Journal of Pain
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• v.18 no.1
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• pp.69-73
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• 2005

This report describes a case of spinal nerve root compression due to an acute inflammatory granuloma after lumbar surgery. A 39 year-old man with a history of increasing back pain with a 3-week duration was diagnosed with a herniated intervertebral disc (HIVD). The diagnosis of a HIVD was confirmed by magnetic resonance imaging (MRI) with indications for surgery. A discectomy and a partial laminectomy was performed and the symptoms were alleviated immediately after surgery for a five-day period. However, a slowly progressing pain was subsequently noted along a different dermatome. There was no pain relief despite the patient being given pharmacological treatments, combined with an epidural steroid injection. The follow up MRI images showed severe compression of the nerve roots by a epidural lesion. Another procedure was performed 17 days after the initial operation. The lesion responsible for the compression of the nerve roots was found to be an acute inflammatory granuloma. The pain was relieved after the second procedure and there were no other symptoms or neurological problems. This case is remarkable in that a granuloma formed relatively quickly and grew to such a size that it was able to severely compress the surrounding nerve roots.

• Journal of the Korean Society of Combustion
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• v.21 no.2
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• pp.29-37
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• 2016

This study described the experimental investigations of combustion instability in a model gas turbine combustor. Strong coupling between pressure oscillations and unsteady heat release excites a self-sustained acoustic wave, which results in a loud and annoyed sound, and may also lead to a structural damage to the combustion system. In this study, in order to examine the combustion instability phenomenon of a dual swirling combustor configuration, the information of heat release and pressure fluctuation period with respect to the variation in both thermal power and combustor length was collected experimentally. As a result, the fundamental acoustic frequency turned out to increase with the increasing thermal power without respect to the combustor length. The frequency response to the combustor length was found to have two distinct regimes. In a higher power regime the frequency significantly decreases with the combustor length, as it is expected from the resonance of gas column. However, in a lower power regime it is almost insensitive to the combustor length. This insensitive response might be a result of the beating phenomenon between the interacting pilot and main flames with different periods.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2005.07a
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• pp.570-571
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• 2005

In this paper, we introduced a LIF measurement method and summarized the theoretical side. When an altered wavelength of laser and electric power, lamp applied electric power, we measured the relative density of the metastable state in mercury after observing a laser induced fluorescence signal of 404.8nm and 546.2nm, and confirmed the horizontal distribution of plasma density in the discharge lamp. The results confirmed the resonance phenomenon regarding the energy level of atoms along a wavelength change, and also confirmed that the largest fluorescent signal in 436nm, and that the density of atoms in 546.2nm ($6^3S_1\rightarrow6^3P_2$) were larger than 404.8nm ($6^3S_1\rightarrow6^3P_1$). According to the increase of lamp applied electric power, plasma density increased, too. When increased with laser electric power, the L1F signal reached a saturation state in more than 2.6mJ. When partial plasma density distribution along a horizontal axis was measured using the laser induced fluorescence method, the density decreased by recombination away from the center.

• Journal of Korean Neurosurgical Society
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• v.55 no.4
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• pp.205-207
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• 2014

Meningioma is a common primary tumor of central nervous system. However, extracranial extension of the intracranial meningioma is unusual, and mostly accompanied the osteolytic change of the skull. We herein describe an atypical meningioma having extracranial extension with hyperostotic change of the skull. The patient was a 72-year-old woman who presented a large mass in the right frontal scalp and left hemiparesis. Brain magnetic resonance imaging and computed tomography scans revealed an intracranial mass, diffuse meningeal thickening, hyperostotic change of the skull with focal extension into the right frontal scalp. She underwent total removal of extracranial tumor, bifrontal craniectomy, and partial removal of intracranial tumor followed by cranioplasty. Tumor pathology was confirmed as atypical meningioma, and she received adjuvant radiotherapy. In this report, we present and discuss a meningioma en plaque of atypical histopathology having an extracranial extension with diffuse intracranial growth and hyperostotic change of the skull.

• Bulletin of the Korean Chemical Society
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• v.20 no.10
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• pp.1177-1180
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• 1999

The ab initio SCF MO and density functional theory (DFT) studies are carried out on the electrophilic (1a) and electron transfer (1b) addition reactions to the vinyl double bond of aryl vinyl sulfides and ethers. In the electrophilic addition processes, a double bond shift from C3 = C4 to X = C3 occurs with occupation number (1.97) close to the normal two. Due to this shift direct conjugation between the cationic center, X = S or O, and the para electron-donor substituent becomes impossible so that the reaction energies (or log K) are correlated with σ rather than σ+. By contrast, radical cation formation leads to delocalization of the SOMO, a lone-pair πorbital on X, with four major resonance structures in which cationic charge as well as spin density is delocalized over C4 , X and C7 atoms. As a result, partial πbonds are formed over C1 -X and C3 - C4 with occupation numbers (0.82) lower than one. In two of the cannonical structures, III(Ⅹ) and III(X+), direct conjugation between the cationic center, X, and the para substituent is achieved so that a better correlation with σ+ rather than σis obtained. The SCF MO energies at the HF/3-21G* and HF/6-31G* levels lead to very much inferior Hammett correlations in the σ/ σ+ diagnostic criterion. In contrast, the ρvalues evaluated with the DFT energies can give reliable diagnostic distinction between the two addition mechanisms.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.14 no.12
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• pp.4816-4834
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• 2020

This paper proposes transfer learning and fine-tuning techniques for a deep learning model to detect three distinct brain tumors from Magnetic Resonance Imaging (MRI) scans. In this work, the recent YOLOv4 model trained using a collection of 3064 T1-weighted Contrast-Enhanced (CE)-MRI scans that were pre-processed and labeled for the task. This work trained with the partial 29-layer YOLOv4-Tiny and fine-tuned to work optimally and run efficiently in most platforms with reliable performance. With the help of transfer learning, the model had initial leverage to train faster with pre-trained weights from the COCO dataset, generating a robust set of features required for brain tumor detection. The results yielded the highest mean average precision of 93.14%, a 90.34% precision, 88.58% recall, and 89.45% F1-Score outperforming other previous versions of the YOLO detection models and other studies that used bounding box detections for the same task like Faster R-CNN. As concluded, the YOLOv4-Tiny can work efficiently to detect brain tumors automatically at a rapid phase with the help of proper fine-tuning and transfer learning. This work contributes mainly to assist medical experts in the diagnostic process of brain tumors.

• Journal of Korean Neurosurgical Society
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• v.66 no.2
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• pp.199-204
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• 2023

It is critical to identify the ruptured cerebral arteriovenous malformations (AVMs) for secondary prevention. However, there are rare cases unidentified on the radiological evaluation. We report on a patient with the delayed appearance of radiologically occult AVM as a probable cause of the previous intracerebral hemorrhage (ICH). An 18-year-old male patient presented with a right temporal ICH. The preoperative radiological examination did not reveal any causative lesions. Because of the intraoperative findings suggesting an AVM, however, only hematoma was evacuated. Disappointedly, there were no abnormal findings on postoperative and follow-up radiographic examinations. Eleven years later, the patient presented with an epileptic seizure, and an AVM was identified in the right temporal lobe where ICH had occurred before. The patient underwent partial glue embolization followed by total surgical resection of the AVM and anterior temporal lobe. Based on the literature review published in the era of magnetic resonance imaging, common clinical presentation of radiologically occult AVMs included headache and seizure. Most of them were confirmed by pathologic examination after surgery. In cases of the ICH of unknown etiology in young patients, long-term follow-up should be considered.

• Archives of Plastic Surgery
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• v.50 no.5
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• pp.488-491
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• 2023

Silicone breast implant insertion is a commonly performed surgical procedure for breast augmentation or reconstruction. Among various postoperative complications, infection is one of the main causes of patient readmission and may ultimately require explantation. We report a case of infective costochondritis after augmentation mammoplasty, which has rarely been reported and is therefore difficult to diagnose. A 36-year-old female visited the clinic for persistent redness, pain, and purulent discharge around the left anteromedial chest, even after breast implant explantation. Magnetic resonance imaging showed abscess formation encircling the left fourth rib and intracartilaginous and bone marrow signal alteration at the left body of the sternum and left fourth rib. En bloc resection of partial rib and adjacent sternum were done and biopsy results confirmed infective costochondritis. Ten months postoperatively, the patient underwent chest wall reconstruction with an artificial bone graft and acellular dermal matrix. As shown in this case, early and aggressive surgical debridement of the infected costal cartilage and sternum should be performed for infective costochondritis. Furthermore, delayed chest wall reconstruction could significantly contribute to the quality of life.

• Clinics in Shoulder and Elbow
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• v.10 no.1
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• pp.27-32
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• 2007

Purpose: To investigate the validity of positive signs of supraspinatus test. Materials and Methods: The empty can test and full can test were performed on 200 shoulders which were diagnosed with magnetic resonance imaging or surgical findings as full thickness tear, partial thickness tear and no tear. Presence of pain, weakness, pain or weakness, and both pain and weakness were recorded as positive signs separately. The two tests with positive signs were compared and analyzed. Results: Pain and weakness were severity-dependent, and the empty-can test had a higher incidence of pain. The sensitivities of the two supraspinatus tests in all positive signs were higher when including partial-thickness tears in the tear group; however, their specificities were higher when excluding partial-thickness tears. The sensitivities of an empty-can test in 'pain', 'pain or weakness', 'both pain and weakness' were higher than those of the full-can test, otherwise, the specificity of the full-can test for 'pain' and 'pain or weakness' were higher. Concordance rate between 'pain or weakness' and 'pain' was the highest in all categorization. Conclusion: Both empty can and full can test were valuable for detecting torn rotator cuff.

• Journal of the Korean Arthroscopy Society
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• v.11 no.1
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• pp.24-31
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• 2007

Purpose: To evaluate any combined rotator cuff pathologies in adhesive capsulitis patients with magnetic resonance arthrography (MRA) or ultrasonography (USG), and to see any differences in findings between MRA and USG. Materials and Methods: From June to December 2005, 80 consecutive patients with adhesive capsulitis were prospectively evaluated with either MRA or USG. Two groups were randomly assigned for examination. Evaluation were focused on any combined rotator cuff pathologies especially supraspinatus tendon. Results: Small (less than 1 cm) full-thickness SSP tendon tear were seen in 6 patients (MRA 4, USG 2, 8%) and partial-thickness SSP tendon tears in 21 (MRA 12, USG 9, 26%). In addition, supraspinatus tendinopathy were seen in 15 patients (MRA 7, USG 8, 19%). Overall, various SSP pathologies were reported in 42 patients (53%) of the study objects (MRA 23, 68% and USG 19, 41%). Subscapularis tendon partial tears were reported in 9 patients (MRA 6, USG 3, 11%). There were no statistical differences of the findings between MRA and USG in detecting rotator cuff pathologies (p>0.5). Conclusion: Nearly one half of the adhesive capsulitis patients showed various supraspinatus tendon pathology in MRA or USG. Although MRA group showed slight higher percentage of associated rotator cuff pathology than USG group (without statistical significance), this could be attributed to better resolution capacity of MRA than USG.