• Journal of the Korean GEO-environmental Society
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• v.25 no.5
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• pp.29-37
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• 2024

This study aimed to investigate the changes in chemical components that occur when weak clay is mixed with steel slag modified with calcium oxide, and to understand the expression characteristics of compressive strength according to hydrophilicity and curing time. XRF testing, SEM imaging, vane shear strength and uniaxial compressive strength testing were conducted. Calcium (Ca) released from the steel slag increases the Ca content in clay by increasing the number of crystal particles and forming a coating layer known as calcium silicate hydrate (CaO-SiO₂-H₂O) through chemical reactions with SiO₂ and Al₂O₃ components. The weak clay stabilized with steel slag is classified into an initial inactive zone where strength relatively does not increase and an activation zone where strength increases over curing time. The vane shear strength of the initial inactive area was found to be 4.4 to 18.4 kN/m² in the state of the weight mixing ratio Rss 30% (steel slag 30% + clay 70%). In the case of the active area, the maximum uniaxial compressive strength increased to 431.8 kN/m² after 480 hours of curing time, which increased due to the apparent adhesion strength of clay through pozzolanic reaction. Therefore, considering the strength expression characteristics of stabilized mixed clay based on the mixing ratio (Rss) during the recycling of steel slag can enhance its practicality in civil engineering sites.

• Journal of the Korea Concrete Institute
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• v.29 no.1
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• pp.85-92
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• 2017

This study examines the characteristics of mortar mixed with various boron compounds. The adapted boron compounds, classified into acid, slightly alkaline and strongly alkaline with respect to the value of the pH are acid-based boron (AA), low-alkaline-based boron (AB), and high-alkaline-based boron (HB). The pH test, setting test and compressive strength test are performed to evaluate the physical and chemical properties of mortar, and SEM imaging is conducted to analyze the microstructure of mortar. The measured pH shows that the specimens mixed with boron compounds have lower pH than the basic mortar without boron and that loss of pH occurs according to time. The setting test reveals that the initial and final setting times of the specimens mixed with boron compounds occur later than the basic mortar, which disagrees slightly with the previous literature stating that the setting time can be shortened according to the alkalinity. From the compressive strength test and SEM imaging results, it is recommended to determine the optimal content of boron considering type and composition of the boron compounds.

• Journal of Korean Neurosurgical Society
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• v.29 no.7
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• pp.891-898
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• 2000

Objective : It is difficult to differentiate intramedullary spinal cord tumors preoperatively from non-neoplastic pathologies in patients presenting as non-compressive myelopathies in magnetic resonance imaging(MRI). In this report, the authors reviewed nonneoplastic intramedullary spinal cord lesions preoperatively diagnosed as tumors and discussed their clinical and radiological characteristics and usefulness of surgical intervention. Methods : From January, 1985 to January, 1999, authors experienced eight non-neoplastic pathologies mimicking intramedullary spinal cord tumors and analysed their medical records, radiological findings and histopathological specimens retrospectively. Results : There were five males and three females and the duration of symptoms were from two to 20 months(mean, 9.8 months). The location of lesions were four cervical, one cervicothoracic and three thoracic. All patients manifested sensory abnormality, seven motor weakness, and six bladder symptom. All cases had swollen spinal cords and increased signal intensities in spin-echo sequences. Six cases showed contrast enhancement : four cases were focal and two diffuse. Under the impression of intramedullary tumors, the patients were operated upon. Final diagnoses on the base of clinical and pathologic finding were : three subacute necrotizing myelopathies, two multiple scleroses, two myelopathy of unknown etiology. One case showed no gross abnormality in surgical field in spite of adequate exposure of the lesion, so biopsy was not performed. In that case, postoperative MRI revealed spontaneous resolution of the lesion. Conclusion : MRI is invaluable diagnostic tool in screening myelopathies. However, its high sensitivity and lack of specificity make difficulty in preoperative differential diagnosis of non-compressive myelopathies. Although no surgical morbidity occurred in our series, we sometimes failed to confirm definite diagnosis even with biopsy. In such a circumstance, long-term follow up is needed.

• Imaging Science in Dentistry
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• v.35 no.3
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• pp.167-173
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• 2005

Purpose : To investigate the relationship between three-dimensional (3D) bone imaging parameters and trabecular strength in the mandible. Materials and Methods : Bone specimens were obtained from the mandibles of five male pigs weighing around 110 kg each. Of those, 43 samples were selected for 3D analysis and measured by micro-computed tomography. The five morphometric parameters were trabecular thickness (Tb.Th), bone specific surface (BS/BV), percent bone volume (BV/TV), structure model index (SMI) and degree of anisotropy (DA). Through destructive mechanical testing, strength parameters were obtained. Results : BV/TV, SMI, BS/BV, and Tb.Th showed significant correlations with strength parameters. DA did not show any correlation with the other parameters. In multiple linear regression analysis, BV/TV alone explained $43\%$ of the variance in Young's modulus. By stepwise inclusion of SMI, the variance in the Young's modulus was better explained up to $52\%$. Conclusions : Predicting trabecular strength in the mandible through architectural analysis would be possible. Further study is needed to establish the tendency and variety of trabecular architecture and strength according to the locations within the mandible.

• Archives of Plastic Surgery
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• v.33 no.6
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• pp.769-772
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• 2006

Purpose: Benign symmetrical lipomatosis(Madelung's disease) is a disease of uncertain etiology that manifests as massive lipomatous deposits in specific area of the body. It is usually located on the neck, shoulder, proximal regions of the extremities and the abdomen. Madelung's disease is found many in middle-aged, Mediterranean man. Imaging using either computed tomography or magnetic resonance imaging is often recommended. Dietary restriction provides no relief of disease. Abstinence with alcohol may delay further progression but does not regression tumor mass. The objective of this study is to prove effectiveness of liposuction for treatment of benign lipomatosis. Methods: We conducted liposuction as a treatment for benign lipomatosis. After general anesthesia, We conducted power assisted liposuction and amount of suctioned volume was about 2500 cc. After surgery, we did compressive dressing and then followed by pressure garment. Results: Six months after surgery, patient was examined for follow up at outpatient department. Recurred lipoma was not observated. Patient was satisfied with result.Conclusion: The only effective therapy for Madelung's disease is surgical removal but recurrence could be occurring. Also multiple surgical scars will be visible. We report a patient with multiple large lipomatosis successfully treated with liposuction.

• Tribology and Lubricants
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• v.38 no.6
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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.

• Journal of Korean Neurosurgical Society
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• v.29 no.8
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• pp.1085-1088
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• 2000

Spinal intradural extramedullary metastasis are very rare. The authors report a case of spinal metastasis at the T5 level in the intradural extramedullary space in a 76-year-old man who presented with paraparesis and sciatica. Preoper-ative neuroradiologic imaging studies were highly suggestive of intradural mass lesion with compressive myelopathy. Pathology revealed metastatic squamous cell carcinoma. We describle the mechanism of tumor spread in intradural spinal metastasis.

• Archives of Plastic Surgery
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• v.38 no.1
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• pp.117-120
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• 2011

Purpose: Carpal tunnel syndrome is the most common peripheral compressive neuropathy. Most cases are idiopathic, but rarely carpal tunnel syndrome can be associated with a ganglionic mass. We report our recently encountered experience of surgical treatment of carpal tunnel syndrome caused by a simple ganglionic mass. Methods: A 53-year-old man presented with chief complaints of numbness and hypoesthesia of his left palm, thumb, index finger, long finger, and ring finger of one and half month duration. Physical examination revealed positive Tinnel's sign without previous trauma, infection or any other events. Electromyography showed entrapment neuropathy of the median nerve. Magnetic resonance imaging (MRI) showed an approximately 2.0 cm-sized mass below the transverse carpal ligament. Upon surgical excision, a $1{\times}1.5cm^2$ mass attached to the perineurium of the median nerve and synovial sheath of the flexor digitorum superficialis and redness and hypertrophy of the median nerve were discovered. With surgical intervention, we completely removed the ganglionic mass and performed surgical release of the transverse carpal ligament. Results: The pathology report confirmed the mass to be a ganglion. The patient exhibited post-operative improvement of his symptoms and did not show any complications. Conclusion: We present a review of our experience with this rare case of carpal tunnel syndrome caused by a ganglionic mass and give a detailed follow-up on the patient treated by surgical exploration with carpal tunnel release.

• Journal of the Korea institute for structural maintenance and inspection
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• v.12 no.2
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• pp.91-102
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• 2008

Nondestructive testing techniques have been historically and commonly used to evaluate the quality of existing concrete structures. The techniques utilized included visual inspection, hammer sounding, Schmidt hammer rebounding, and ultrasonic pulse velocity testing including tomographic imaging. Results of the nondestructive tests were used to determine areas to be tested with local destructive tests. These tests included concrete compressive strengths, chloride testing, and petrographic testing. The overall results indicate that inside core of each of the pier caps are healthy. On all of the pier caps, extensive exterior concrete layer rehabilitation needs to be completed. This paper shows the application and interpretation of common nondestructive testing techniques and the consequent repair, rehabilitation, maintenance decisions and safety assesment.

• Journal of Electrodiagnosis and Neuromuscular Diseases
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• v.20 no.2
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• pp.153-158
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• 2018

Posterior interosseus (PI) nerve compression is a rare form of compressive neuropathy. It can cause pain along the radial nerve course and weakness of radial nerve innervating muscles without sensory symptoms. A 65-year-old man visited our institution complaining weakness of finger extension and thumb abduction after 2 times of injections at the right elbow in local clinic. The patient's clinical history and physical examination implied an iatrogenic radial nerve injury caused by the injection. The electrophysiologic study revealed of posterior interosseus neuropathy (PIN) with incomplete conduction block. However, the ultrasound study showed that the PI nerve was compressed by an anechoic cyst. The magnetic resonance imaging also confirmed of a ganglion cyst, not a hematoma. After repeated aspirations and a steroid injection, the electrophysiologic study showed recovery of motor weakness. Despite of the clue which implying an iatrogenic injury, clinician should consider other possibilities such as ganglion cysts and ultrasound guided aspiration and steroid injection could be an effective option for conservative management.