• Polymer(Korea)
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• v.25 no.3
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• pp.318-326
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• 2001

PLLA scaffold loaded with gentamicin sulfate (GS) was prepared by emulsion freeze-drying method for the prevention of infection and the improvement of wettability. i.e., the cell- and tissue-compatibility. GS-loaded PLLA scaffolds were characterized by scanning electron microscopy (SEM), mercury porosimetry and blue dye intrusion, and the GS release pattern was analyzed by high performance liquid chromatography (HPLC). GS-loaded PLLA scaffolds with porosity above 50%, medium pore size ranging from 30 to 57 ${\mu}{\textrm}{m}$ (with larger pore diameters greater than 150 ${\mu}{\textrm}{m}$), and specific pore area in the range of 35 to 75($m^2$ /g )were manufactured by varying processing parameter as GS concentration. It was observed that GS-loaded PLLA scaffolds were highly porous with good interconnections between pores for allowing cell adhesion and growth. These scaffolds may be applicable for scaffold as structures that facilitate either tissue regeneration or repair during reconstructive operations.

• Journal of Chest Surgery
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• v.26 no.3
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• pp.180-185
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• 1993

From February 1982 to December 1991, 49 neonates and 105 infants in less than 3 months of age underwent open heart surgery in Seoul National University Hospital. There were 98 males and 56 females, and their mean ages were 16 days in neonatal group and 67 days in early infant group. Their body weight and height were less than 3 percentile of normal developmental pattern. In order of decreasing incidence, the corrected conditions included Transposition of great arteries with or without ventricular septal defect [43], isolated ventricular septal defect [34], Total anomalous pulmonary venous return [21], Pulmonary atresia with intact ventricular septum [9] and others [47]. Various corrective or palliative procedures were performed on these patients; Arterial switch operation [36], patch closure for ventricular septal defect [34], Repair of total anomalous pulmonary venous return [21], RVOT reconstruction for congenital anomalies with compromised right ventricular outflow tract [17]. Profound hypothermia and circulatory arrest were used in 94 patients [ 61% ]: 42 patients [ 85.7% ] for neonatal group and 52 patients [ 49.5% ] for early infant group. The durations of circulatory interruption were within the safe margin according to the corresponding body temperature in most cases [ 84% ]. The hospital mortality was 36.4% ; 44.9% in neonatal group and 32.4% in infant group 1 to 3 months of age. The mortality was higher in cyanotic patients [ 46.6% ], in those who underwent palliative procedures [ 57.8% ], in patients whose circulatory arrest time was longer than safe periods [ 60% 0] and in patients who had long periods of cardiopulmonary bypss and aortic crossclamping. In conclusion, there has been increasing incidence of open heart surgery in neonates and early infants in recent years and the technique of deep hypothermia and circulatory arrest was applied in most of these patients, and the mortality was higher in cyanotic neonates who underwent palliative procedures and who had long cardiopulmonary bypass , aortic cross-clamping and circulatory arrest.

• Journal of Environmental Science International
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• v.9 no.2
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• pp.115-123
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• 2000

The dynamics of water quality and phytoplankton population had examined by monthly sampling from the upper to the lower part of watergate in an artificial Shihwa Reservoir in which situated near newly cities and incustrial complex on the west coast of Korea from January 1997 to December 1998. Among environmental factors, yearly average concentration of chl-a, TN and TP seemed to eutrophic or hypertrophic conditions that ranged 146.4~245.8 $\mu\textrm{g}$/$\ell$, 1.6~2.7 mg N/$\ell$, 258~448 $\mu\textrm{g}$ P/$\ell$, 26.9~80.7 $\mu\textrm{g}$/$\ell$, 1.0~2.4 mgN/$\ell$ and 74~239 $\mu\textrm{g}$P/$\ell$ respectively. Water quality was extremely deteriorated to consistently accumulation into inner reservoir by load of pollutants from autochthonous and allochthonous until early July 1997 after embankment. Water pollution of Shihwa Reservoir was remarkble on the biological condition with largely persistent bloom of phytoplankton and increase rate of standing crops was 2.4/yr. The development trend of phytoplankton in water ecosystem were closely related to increse and decrease of physico-chemical factors and those scale seemed to control by nutrient contents. Inflow of seawater into reservoir to object of repair of water quality. As to see dominant species, composition of those composed to mostly freshwater algae before inflow of seawater such as Selenastrum capricornutum of green algae, cyclotella atomus, C. meneghiniana of diatom and Microcystis spp. of blue-green algae and the other hand brackish algae were dominated after inflow of seawater such as Chaetoceros dicipiens, Skeletonema costatum of diatom, Dinophysis acuminata, Gymnodinium mikimotoi, G. sanguineum, Gyrodinium spirale, Prorocentrum minmum of dinoflagellate and Eutreptiella gymnastica of euglenoid. Moreover, small flagellates including Chroomonas spp. of cryptomonad were abundant throughout the year. The cause of water deterioration during fill of the freshwater were complexly supported with extra and intra parameters. The variation pattern of phytoplankton were related to water temperature and salinity by inflow of seawater based to plentiful nutrients. The dynamics of phytoplankton were assessed to ecosystem that clearly condition of dominant by unique or a few angel species seasonally.

• The Journal of Advanced Prosthodontics
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• v.9 no.1
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• pp.22-30
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• 2017

PURPOSE. The aim of this study was to investigate the effect of reinforcing materials on the fracture resistances of glass fiber mesh- and Cr-Co metal mesh-reinforced maxillary complete dentures under fatigue loading. MATERIALS AND METHODS. Glass fiber mesh- and Cr-Co mesh-reinforced maxillary complete dentures were fabricated using silicone molds and acrylic resin. A control group was prepared with no reinforcement (n = 15 per group). After fatigue loading was applied using a chewing simulator, fracture resistance was measured by a universal testing machine. The fracture patterns were analyzed and the fractured surfaces were observed by scanning electron microscopy. RESULTS. After cyclic loading, none of the dentures showed cracks or fractures. During fracture resistance testing, all unreinforced dentures experienced complete fracture. The mesh-reinforced dentures primarily showed posterior framework fracture. Deformation of the all-metal framework caused the metal mesh-reinforced denture to exhibit the highest fracture resistance, followed by the glass fiber mesh-reinforced denture (P<.05) and the control group (P<.05). The glass fiber mesh-reinforced denture primarily maintained its original shape with unbroken fibers. River line pattern of the control group, dimples and interdendritic fractures of the metal mesh group, and radial fracture lines of the glass fiber group were observed on the fractured surfaces. CONCLUSION. The glass fiber mesh-reinforced denture exhibits a fracture resistance higher than that of the unreinforced denture, but lower than that of the metal mesh-reinforced denture because of the deformation of the metal mesh. The glass fiber mesh-reinforced denture maintains its shape even after fracture, indicating the possibility of easier repair.

• Molecules and Cells
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• v.37 no.2
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• pp.126-132
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• 2014

As a tumor suppressor homologue during mitosis, Chk2 is involved in replication checkpoints, DNA repair, and cell cycle arrest, although its functions during mouse oocyte meiosis and early embryo development remain uncertain. We investigated the functions of Chk2 during mouse oocyte maturation and early embryo development. Chk2 exhibited a dynamic localization pattern; Chk2 expression was restricted to germinal vesicles at the germinal vesicle (GV) stage, was associated with centromeres at pro-metaphase I (Pro-MI), and localized to spindle poles at metaphase I (MI). Disrupting Chk2 activity resulted in cell cycle progression defects. First, inhibitor-treated oocytes were arrested at the GV stage and failed to undergo germinal vesicle breakdown (GVBD); this could be rescued after Chk2 inhibition release. Second, Chk2 inhibition after oocyte GVBD caused MI arrest. Third, the first cleavage of early embryo development was disrupted by Chk2 inhibition. Additionally, in inhibitor-treated oocytes, checkpoint protein Bub3 expression was consistently localized at centromeres at the MI stage, which indicated that the spindle assembly checkpoint (SAC) was activated. Moreover, disrupting Chk2 activity in oocytes caused severe chromosome misalignments and spindle disruption. In inhibitor-treated oocytes, centrosome protein ${\gamma}$-tubulin and Polo-like kinase 1 (Plk1) were dissociated from spindle poles. These results indicated that Chk2 regulated cell cycle progression and spindle assembly during mouse oocyte maturation and early embryo development.

• Journal of the Korea Concrete Institute
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• v.25 no.5
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• pp.565-572
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• 2013

Hydration and physical characteristics of chemically-bonded phosphate ceramic (CBPC) binder based on dead-burned Mg-O with six different blends are investigated for efficient repair construction material by retarding set phase with $H_3BO_3$. The test specimen of the blender with silica fume shows higher compressive strength after 75 days. The CBPC with silica fume results in higher modulus of rupture that others. The test specimens of CBPC eludes lower calcium ion than that of OPC (Ordinay Portland Cement). The X-ray diffraction pattern shows that hydration results in the formation of magnesium hydroxide, M-S-H gel and $MgCO_3$ for the specimen with silica fumes. Combination with calcium for MgO is not desirable due to no formation of chemical bond between two components. Based on the experimental program, the mixture of MgO and silica fume shows efficient performance in strength and durability.

• Journal of the Korean Arthroscopy Society
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• v.7 no.2
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• pp.127-136
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• 2003

Posterolateral instability of the knee occurs more commonly in association with an injury to anterior and posterior cruciate ligament and combined injuries are severe injuries that result in significant functional instability and articular cartilage degeneration. Reconstruction of the anterior and posterior cruciate ligament without an appropriate treatment of posterolateral corner injury result in failure of the reconstructed cruciate ligaments. Meticulous physical examinations, imaging studies, lower limb alignment and gait pattern should be evaluated. Acute grade III isolated or combined injury of the posterolateral corner is best treated within three weeks by direct repair, or augumentation, or reconstruction. The appropriate surgical method or combined methods are selected among the several methods of posterior and posterolateal reconstruction, and all injuried posterolateral and cruciate ligament structures are anatomically reconstructed simultaneously or by stages. If a varus alignment and varus thrust is disclosed in chronic posterolateral instability of knee, soft tissue reconstructions laterally are highly unlikely to be able to correct tile problem. It is appropriate that valgus osteotomy should be done before soft tissue reconstruction and reevaluate the posterolateral instability about 6 months later.

• Journal of the Korea institute for structural maintenance and inspection
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• v.17 no.1
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• pp.10-20
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• 2013

Because of the defect in design, damage in using period, and deterioration in long term exposure to severe environmental condition, degradation of performance in RC (Reinforced Concrete) structures has occurred. This paper contains durability performance evaluation in railway bridges which covers eight districts through field investigation. For the target structures, durability performance is evaluated and the critical problems in use are derived. Additionally, service lifes for the deteriorated structures are evaluated through Durability-Environment index method based on the results from field investigation, and the results are compared with those from the condition assuming the structures without defect, damage, and deterioration. The target structures which consist of RC T girder, PSC girder, RC box, and Rahmen are investigated and the critical damage patterns are derived. They are evaluated to be cracks in PSC girder end, flexural cracks in PSC girder, crack around EPT anchor, and flexural cracks in RC T girder and RC box. The reasons for the critical patterns are also investigated. This study can be utilized for the repair planning considering the different district and the structure types.

• Archives of Plastic Surgery
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• v.36 no.1
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• pp.46-50
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• 2009

Purpose: Finger injury by green onion cutting machine is one of the common hand injuries in the kitchen. It has a unique feature: there are multiple parellel laceration 3 - 5 mm wide. There are two directions of injuries(vertical, oblique). It may involve bone, tendon, nerve, and vessel injuries. We discuss its management and the long - term progress. Methods: We have treated six patients from 2003 to 2007. We carried out low tension approximation with thin suture materials to avoid ischemia and performed the additional operation as nail bed repair, tenorrhaphy, open reduction, vessel anastomosis, and composite graft. We reviewed the record of initial injury and collected the follow - up record. Results: They were all middle aged - women who had worked in the kitchen. Right hand was dominent over left hand. The ratio of the directions was 3 : 3 (vertical : oblique). They were all competely healed although there were three atrophy, four hyperesthesia, and one nail deformity. Conclusion: Finger injury by green onion cutting machine is a unique pattern of laceration with various accompanied injuries. It may look like a severe form of injury, but in most cases have relatively favorable progress. We have to perform careful examination of accompanied injuries and carry out the proper management. First and foremost, the user especially in the middle aged women should be warned to be careful in handling this risky machine.

• International Journal of Highway Engineering
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• v.14 no.2
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• pp.1-10
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• 2012

As old concrete pavements of over 20years in age are increasing in expressways, the repair and rehabilitation of concrete pavement have become an important issue. Although asphalt overlay is widely used as an alternative to rehabilitate the old concrete pavement, problems due to infiltrated water such as reflection crack and pothole are imposing a very serious threat to its performance. This study proposes waterproof membrane as a solution to minimize the damage due to reflection crack and infiltrated water, and accelerated pavement testing was carried out for the performance comparison of composite pavement with waterproof membrane and ordinary tack coating. The experiment used water spraying to simulate rainfall, and the behavior and moisture resistance characteristics of overlay pavement were analyzed. The experimental result indicated that the strain pattern of waterproof membrane section differed from ordinary tack coating section because waterproof membrane caused the asphalt pavement and concrete pavement to move together. Additionally, since waterproof membrane minimized the infiltration of water and delayed the occurrence of reflection crack by about 70% in comparison to ordinary tack coating method. Moreover, the damage due to infiltrated water also decreased.