• Journal of Korean Ophthalmic Optics Society
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• v.13 no.1
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• pp.71-76
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• 2008

Purpose: A simple and efficient method to prepare nanocrystalline ZnO thin film with pure strong UV emission on soda-lime-silica glass substrates by low-temperature annealing was improved. Methods: Crystal structural, surface morphological, and optical characteristics of nanocrystalline ZnO thin films deposited on soda-lime-silica glass substrates by prefiring final annealing process at 300$^{\circ}C$ were investigated by using X-ray diffraction analysis, field emission-scanning electron microscope, scanning probe microscope, ultraviolet-visible-near infrared spectrophotometer, and photoluminescence. Results: Highly c-axis-oriented ZnO films were obtained by prefiring at 300$^{\circ}C$. A high transmittance in the visible spectra range and clear absorption edge in the ultra violet range of the film was observed. The PL spectrum of ZnO thin film with a deep near band edge emission was observed while the defect-related broad green emission was nearly quenched. Conclusions: Our work will be possibly adopted to cheaply and easily fabricate ZnO-based optoelectronic devices at low temperature, below 300$^{\circ}C$, in the future.

• Clinical and Experimental Pediatrics
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• v.49 no.4
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• pp.455-459
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• 2006

The major pathogenesis of acute respiratory distress syndrome (ARDS) is an inflammatory process that results from a diversity of injuries to the body. Due to the various cytokines and vasoactive peptides released from the endothelium, the vascular permeability is increased; the migration of inflammatory cells and the leakage of plasma proteins then occur and edema develops in the alveolus. There is a hypothesis that the impairment of alveolar recruitment in ARDS is caused by a defect of the surfactant system and the resultant increase of alveolar surface tension. This has been studied in pediatric patients in ARDS; after the administration of surfactant, hypoxia, respiratory symptoms and survival chances were improved. To alleviate the major pathogenic mechanism in this disease, that is to say, inflammation of the lung, steroids have been used and studied as another treatment modality for ARDS, and it has been concluded that the administration of low dose methylprednisolone may improve patients' symptoms and survival rates. We report here on a case of a young infant admitted with ARDS, who, after the intratracheal administration of 120 mg/kg surfactant, on $PaO_2/FiO_2$ was elevated. Subsequent low doses of methylprednisolone were given, and the symptoms did not recur, and no fibrotic change was shown during the follow-up period of 2 months.

• Clinical and Experimental Pediatrics
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• v.45 no.3
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• pp.413-417
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• 2002

Gitelman's syndrome is an autosomal recessive disorder characterized by hypokalemic metabolic alkalosis, hypomagnesemia, and hypocalciuria that has recently been reported to be linked to thiazide- sensitive Na-Cl cotransporter gene mutation. In this study, we performed renal clearance studies to differentiate Gitelman's from Bartter's syndrome and to confirm the diagnosis in two patients clinically diagnosed with Gitelman's syndrome. Each patient was hydrated by 20 mL/kg body weight of oral water within 30 minutes, which was followed by intravenous half saline. When urinary flow reached 10 mL/min, samples of urine and serum were obtained to calculate the osmolar clearance, free water clearance, chloride clearance, and distal fractional chloride reabsorption. Subsequently, furosemide or hydrochlorothiazide was administered. Samples were collected and the same parameters were calculated. In our patients, chloride clearance was increased more than 10 times after furosemide administration(2.1 : 25.7 and 2.2 : 27.4 mL/min/100 mL GFR), but not increased after hydrochlorothiazide treatment(2.1 : 1.6 and 2.2 : 2.6 mL/min/100 mL GFR). And the distal fractional chloride reabsorption was significantly decreased by furosemide injection (73% : 15% and 75% : 4.6%), whereas hydrochlorothiazide had no effect on it(73% : 63% and 75% : 78%). These findings indicate that our patients have a defect in thiazide-sensitive Na-Cl cotransporter in the distal tubule, which is compatible with the pathophysiology of Gitelman's syndrome.

• Journal of Biomedical Engineering Research
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• v.31 no.3
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• pp.199-209
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• 2010

The locking compression plates-distal femur(LCP-DF) are being widely used for surgical management of the extra-articular complex fractures of the distal femur. They feature locking mechanism between the screws and the screw holes of the plate to provide stronger fixation force with less number of screws than conventional compression bone plate. However, their biomechanical efficacies are not fully understood, especially regarding the number of the screws inserted and their optimal configurations. In this study, we investigated effects of various screw configurations in the shaft and the condylar regions of the femur in relation to structural stability of LCP-DF system. For this purpose, a baseline 3-D finite element (FE) model of the femur was constructed from CT-scan images of a normal healthy male and was validated. The extra-articular complex fracture of the distal femur was made with a 4-cm defect. Surgical reduction with LCP-DF and bone screws were added laterally. To simulate various cases of post-op screw configurations, screws were inserted in the shaft (3~5 screws) and the condylar (4~6 screws) regions. Particular attention was paid at the shaft region where screws were inserted either in clustered or evenly-spaced fashion. Tied-contact conditions were assigned at the bone screws-plate whereas general contact condition was assumed at the interfaces between LCP-DF and bone screws. Axial compressive load of 1,610N(2.3 BW) was applied on the femoral head to reflect joint reaction force. An average of 5% increase in stiffness was found with increase in screw numbers (from 4 to 6) in the condylar region, as compared to negligible increase (less than 1%) at the shaft regardless of the number of screws inserted or its distribution, whether clustered or evenly-spaced. At the condylar region, screw insertion at the holes near the fracture interface and posterior locations contributed greater increase in stiffness (9~13%) than any other locations. Our results suggested that the screw insertion at the condylar region can be more effective than at the shaft during surgical treatment of fracture of the distal femur with LCP-DF. In addition, screw insertion at the holes close to the fracture interface should be accompanied to ensure better fracture healing.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.12
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• pp.6413-6419
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• 2013

This study examined the irradiation effect of high energy x-rays on the hatching process of fertilized eggs, particularly with regard to malformation and blood cells change. The experimental groups were five day old fertilized eggs irradiated with x rays at doses of 5, 7.5, 10 Gyusing alinear accelerator. The control group was not irradiated. After three weeks, hatched chicks were sacrificed and examined for blood sampling. The survival rate of the x-ray irradiated groups were significantly lower than that of the control group (46.7vs 80%). The malformation rate of the experimental groups was60%, whereas no congenital malformations were observed in the control group. The experimental groups had a significantly higher malformation rate. The types of malformation were left wing defect, proptosis, microcephaly, cervical spine, and feet anomaly. The incidence of malformation increased with increasing radiation dose. The white blood cell count of control group and eachexperimental groups (5 and 7.5 Gy) were 87.64, 100.76 and 81.42 ($10^3/{\mu}L$), respectively. X-ray irradiation of 5 day old chick embryos increased the rate of death and malformation significantly.The malformations were estimated to have occurred by chromosomal abnormalities. Further genetic studies will be needed to confirm the correlation between high energy X-rays and the cause of malformations.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.8
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• pp.593-602
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• 2020

Power cables installed in domestic factories or underground can cause accidents depending on the manufacturing process, installation, and environmental conditions during use. When an accident occurs in a power cable, it can cause enormous economic loss and social confusion. Hence, the importance of preventive management of the cable through diagnosis is increasing to prevent it. Therefore, in this paper, a diagnostic sample cable was produced by simulating a part that could be a problem due to the installation, manufacturing defects, or deterioration of cables that can occur in the field. Dielectric loss Tangent (tan 𝛿; TD), and Partial Discharge(PD) tests were performed. Partial discharge and AC (60Hz) withstand voltage equipment using High-Frequency Current Transformer (HFCT) were applied After applying a VLF (Very Low Frequency) power supply with a frequency of 0.1Hz was applied. As a result, B and C phase defect samples at a 2.0U₀ voltage through the VLF could measure the internal partial discharge in the A-phase normal sample cable from the noise at a 0.5U₀ to 2.0U₀ voltage. In addition, the 1.5U₀ voltage was measured through the AC (60Hz) withstand voltage equipment of the commercial frequency to verify its effectiveness. Partial discharge in the run-off state was measured at a voltage of 1.0U₀, and there was a risk when installing the equipment. AC power equipment showed a difficulty of movement by volume or weight. The diagnostic method, through the VLF of the quadrant state, revealed its safety and effectiveness.

• Korean Journal of Materials Research
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• v.21 no.1
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• pp.8-14
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• 2011

To improve the chemical stability of metal, the ceramic coatings on metallic materials have attracted interest from many researchers due to the chemical inertness of ceramic materials. To endure strong acids, SiOC coating on metal substrate was carried out by dip coating method using 20wt% polyphenylcarbosilane solution; SiC powder was added to the solution at 10wt% and 15wt% to improve the mechanical properties and to prevent cracks of the film. Thermal oxidation as a curing step was carried out at $200^{\circ}C$ for crosslinking of the polyphenylcarbosilane, and the coating samples were pyrolysized at $800^{\circ}C$ under argon to convert the polyphenylcarbosilane to SiOC film. The thicknesses of the SiOC coating films were $2.36{\mu}m$ and $3.16{\mu}m$. The quantities of each element were measured as $SiO_{1.07}C_{6.33}$ by EPMA, and it can be confirmed that the SiOC film from polyphenylcarbosilane was formed in a manner that was carbon rich. The hardness of the SiOC film was found to be 3.2Gpa through nanoindentor measurement. No defect including cracks appeared in the SiOC film. The weight loss of the SiOC coated stainless steel was within 2% after soaking in 10% HCl solution at $80^{\circ}C$ for one week. From these results, SiOC coating shows good potential for application to protect against severe chemical corrosion of stainless steel.

• Journal of Veterinary Clinics
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• v.23 no.4
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• pp.461-464
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• 2006

Perineal hernia occurs spontaneously in older male dogs after idiopathic weakening of the pelvic diaphragm A 14-year-old uncastrated male shih tzu dog with right-sided perineal swelling was referred to the Veterinary Medical Teaching Hospital of Konkuk University. He had sign of perineal swelling for three years. Plain radiography documented the extent of rectal and colonic dilation in the herinal sac. During surgery, external anal sphincter muscle, coccygeus muscle and levator am muscle were weakened due to the three years of herniation. Internal obturator muscle transposition method was not enough for large defect, so mesh was applied to reduce the hernial sac. Internal obturator muscle transposition combined with using of polypropylene mesh was successfully performed in this dog.

• Journal of Chest Surgery
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• v.31 no.12
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• pp.1226-1229
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• 1998

50 days old, 4.5kg male patient was admitted at department of pediatrics due to congenital heart disease with congestive heart failure. The echocardiographic finding was perimembranous type ventricular septal defect. The patient underwent open heart surgery for patch closure of VSD. Immediately postoperatively, junctional ectopic tachycardia developed and the patient was in hemodynamically unstable state with decreased urine output. We used inotropics, digitalis and diuretics, however these treatments were not effective in recovering the unstable state. Therefore, we tried a mild hypothermic treatment(34℃). During the POD #2, mild hypothermia method was repeated four times. The junctional ectopic tachycardia was converted to normal sinus rhythm, hemodynamic state was stable, and urine output was increased. The patient was discharged at POD #8.

• Journal of Chest Surgery
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• v.32 no.2
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• pp.206-210
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• 1999

We report here 2 cases of deep-seated mediastinitis combined with sternal osteomyelitis after tracheal reconstruction which were successfully treated with sternectomy, in-situ or free omental transfer, and pectoralis major myocutaneous flap. In case I, an 8 year-old boy with deep seated mediastinitis and sternal osteomyelitis that developed after anterior tracheoplasty through a standard midline sternotomy. In case II, a 50 year-old female patient with mediastinal abcess and sternal osteomyelitis that developed after resection and end-to-end anastomosis of the trachea through an upper midline sternotomy. Treatments consisted of drainage and irrigation followed by wide resection of the infected sternum, placement of the viable omentum into the anterior mediastinal space, and chest wall reconstruction with a pectoralis major myocutaneous flap. The omentum was transferred as an in-situ pedicled graft in case I and a free graft in case II. Both patients have recovered smoothly wit out any events and have been doing well postoperatively.