• The Journal of Korean Physical Therapy
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• v.15 no.4
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• pp.46-64
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• 2003

Therapeutic angiogenesis is the controlled induction or stimulation of new blood vessel formation to reduce unfavourable tissue effects caused by local hypoxia and to enhance tissue repair. Therapeutic ultrasound can be considered as a physical agent to deliver therapeutic angiogenesis. The purpose of this study was to evaluate the effect of therapeutic ultrasound after muscle contusion injury by observed immunoreactivity of vascular endothelial growth factor(VEGF) that plays an important role in angiogenesis and substance-P in pain transmission. Ultrasound irradiation(1MHz, $1W/cm^2$, continuous mode, treatment time 5 min) was applied through water submersion technique to 1 limb daily by kept off 5cm from muscle belly of gastrocnemius. The result of this study were as follows. 1. In morphological observation, there were no significant changes excepts of 7 days. At 7 days, granular tissue viewed abundantly in control group. In other groups, general feature were increased interspace of muscle fiber; centronucleated muscle fiber; collapsed of muscle and nerve tissue; appeared inflammatory cell. 2. The VEGF was expressed in interspace of muscle fiber. Especially, at 7 days in experimental group, VEGF was showed in connective tissue surrounding gastrocnemius muscle. 3. The VEGF was higher expressed in experimental group at 2 and 3 days, but in control group at 7 days. These data suggest therapeutic ultrasound enhanced production of VEGF in the early day relatively, therefore stimulated angiogenesis in the skeletal muscle induced contusion injury. Also therapeutic ultrasound may stimulate pain relief by diminish of substance-P in dorsal horn of spinal cord.

• Journal of the Korea institute for structural maintenance and inspection
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• v.14 no.6
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• pp.124-131
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• 2010

Rock Bolt generally utilizes deformed reinforcing bar welded from structural steel of which strength is higher than required for making advantageous use of the support function of ground. In the condition with highly corrosive underground water, however, problem frequently occurs on tunnel and slope stabilization in terms of repair, rehabilitation and maintenance issues due to the destruction of Rock Bolt by corrosion of steel. A structural performance evaluation for GFRP Rock Bolt was conducted for the purpose of resolving the foregoing problem and at the same time developing a permanently-usable support material. This study intended to evaluate the safety factor of GFRP Rock Bolt by implementing the slope stability interpretation via structural analysis on the basis of its structural characteristics derived from both tensile force function test and shear force function test. It is judged based on the results that GFRP Rock Bolt would secure sufficient ground stability as an alternative material for existing Steel Rock Bolt.

• Journal of Korea Water Resources Association
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• v.51 no.11
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• pp.959-969
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• 2018

The aging water pipes induce various problems, such as water supply suspension due to breakage, insufficient water pressure, deterioration of water quality, damage by sink holes, and economic losses due to water leaks. However, it is impractical and almost impossible to repair and/or replace all deteriorated water pipes simultaneously. Hence, it is required to quantitatively evaluate the deterioration rate of individual pipes indirect way to determine the rehabilitation order of priority. In this study, ANN(Artificial Neural Network)-Clustering method is suggested as a new approach to assess and assort the water pipes. The proposed method has been applied to a water supply network of YG-county in Jeollanam-do. To assess the applicability of the model, the evaluation results were compared with the results of the Numerical Weighting Method (NWM), which is being currently utilized in practice. The assessment results are depicted in a water pipe map to intuitively grasp the degree of deterioration of the entire pipelines. The application results revealed that the proposed ANN-Clustering models can successfully assess the water pipe deterioration along with the conventional approach of NWM.

• Journal of Dental Rehabilitation and Applied Science
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• v.38 no.1
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• pp.52-59
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• 2022

Decalcification of the buccal surface of the teeth often occurs during fixed orthodontic treatment. This case report describes two cases in which cervical decalcificated teeth that occurred during orthodontic treatment were treated with direct resin veneer restoration. Early lesions without caries can be remineralized through periodic fluoride application, diet control, and oral hygiene improvement. As it progresses, appropriate repair treatment is required, and it is more preferable to focus on prevention rather than treatment after the occurrence of the lesion.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.30 no.3A
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• pp.201-209
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• 2010

Generally, PSC girder bridge uses total gross cross section to resist applied loads unlike reinforced concrete member. Also, it is used as short and middle span (less than 30 m) bridges due to advantages such as ease of design and construction, reduction of cost, and convenience of maintenance. But, due to recent increased public interests for environmental friendly and appearance appealing bridges all over the world, the demands for longer span bridges have been continuously increasing. This trend is shown not only in ordinary long span bridge types such as cable supported bridges but also in PSC girder bridges. In order to meet the increasing demands for new type of long span bridges, PSC hollow box girder with H-type steel as compression reinforcements is developed for bridge with a single span of more than 50 m. The developed PSC girder applies compressive prestressing at H-type compression reinforcements using unbonded PS tendon. The purpose of compressive prestressing is to recover plastic displacement of PSC girder after long term service by releasing the prestressing. The static test composed of 4 different stages in 3-point bending test is performed to verify safety of the bridge. First stage loading is applied until tensile cracks form. Then in second stage, the load is removed and the girder is unloaded. In third stage, after removal of loading, recovery of remaining plastic deformation is verified as the compressive prestressing is removed at H-type reinforcements. Then, in fourth stage, loading is continued until the girder fails. The experimental results showed that the first crack occurs at 1,615 kN with a corresponding displacement of 187.0 mm. The introduction of the additional compressive stress in the lower part of the girder from the removal of unbonded compressive prestressing of the H-type steel showed a capacity improvement of about 60% (7.7 mm) recovery of the residual deformation (18.7 mm) that occurred from load increase. By using prestressed H-type steel as compression reinforcements in the upper part of cross section, repair and rehabilitation of PSC girders are relatively easy, and the cost of maintenance is expected to decrease.

• The Journal of Korean Orthopaedic Ultrasound Society
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• v.1 no.2
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• pp.78-85
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• 2008

Purpose: The findings of preoperative magnetic resonance imaging (MRI) and ultrasonography (US) examination in the diagnosis of rotator cuff tear were then compared with the findings of arthroscopic examination, and to evaluate the postoperative integrity of rotator cuff using serial US examination. Methods: Between February and May 2008, 29 patients with rotator cuff tear had undergone preoperative US and MRI examination and subsequent arthroscopic examination. And the results of MRI and US were compared with intra-operative results of the arthroscopic examination. We observed the postoperative integrity of rotator cuff using serial (postoperative 2 weeks, 6 weeks, 3 months) US examination. Results: The sensitivity of US and MRI for identifying rotator cuff tear were 100% and 100%. The sensitivity of US and MRI were 95% and 82% in full thickness tear, and 50%, 33% in partial thickness tear, respectively. Overall accuracy of US and MRI were 86%, 69%. Among 22 patients were operated for full thickness tear, intra-operative gap formation was identified in 11 patients (50%, small to medium 2 cases, large to massive 9 cases) which were identified at 2 weeks postoperative US. We could find 5 re-tears (23%, small to medium 1 case, large to massive 4 cases) on 6 weeks postoperative US after passive range of motion (ROM) exercise, and could also find 7 re-tears (32%, small to medium 2 cases, large to massive 5 cases)on 3 months postoperative US after active ROM exercise. Conclusion: Serial US after arthroscopic rotator cuff repair was useful to differentiate intra-operative gap formation from postoperative re-tear. We found 5 retears (23%) at 6 weeks and 7 retears (32%) at 3 months postoperative US, it was useful to make treatment plan during postoperative rehabilitation.

• Journal of Dental Rehabilitation and Applied Science
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• v.22 no.2
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• pp.149-159
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• 2006

Statement of problem. Porcelain repair mainly involves replacement with composite resin, but the bond strength between composite resin and all-ceramic coping materials has not been studies extensively. Purpose. The objective of this study was to investigate the influence of composite resin and ceramic etching pattern on shear bond strength of Empress2 ceramic and observe the change of microstructure of ceramic according to etching methods. Material and methods. Eighty-five cylinder shape ceramic specimens (diameter 5mm, IPS Empress 2 core materials) embeded by acrylic resin were used for this study. The ceramic were specimens divided into sixteen experimental groups with 5 specimens in each group and were etched with phosphoric acid(37%, 65%) & hydrofluoric acid (4%, 9%) according to different etching times(30s, 60s, 120s 180s). All etched ceramic surfaces were examined morphologically using SEM(scanning electron microscopy). Etched surfaces of ceramic specimens were coated with silane (Monobond-S) & adhesive(Heliobond) and built up composite resin using Teflon mold. Accomplished specimens were tested under shear loading until fracture on universal testing machine at a crosshead speed 1mm/min; the maximum load at fracture(kg) was recorded. Shear bond strength data were analyzed with one way ANOVA and Duncan tests.(P<.05) Results. Maximum shear bond strength was $30.07{\pm}2.41(kg)$ when the ceramic was etched with 4% hydrofluoric acid at 120s. No significant difference was found between phosphoric etchant group and control group with respect to shear bond strength. Conclusion. Empress 2 ceramic surface was not etched by phosphoric acid, but etched by hydrofluoric acid.

• The Journal of Korean Physical Therapy
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• v.12 no.3
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• pp.319-329
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• 2000

The purpose of this study w8s to evaluate the effects of pulsed electromagnetic energy(Diapulse) and microcurrent on the wound healing in rabbits. 15 domestic rabbits were randomly assigned to the PRME(n=5). MC(n=5) and CON(n=91 group. Each rabbits were anesthetized with lidocaine HCL $2\%$. Skin wounds were created laterally on the back of IS domestic rabbits(33cm). From 24 hours after being injured, the rabbits of the PEME group were irradiated with an intensity of 3 at a 300 pulses per second, which were applied for 15 minutes every day during the 12 days. The MC group were stimulated with an intensity of $50{\mu}A$ at frequency of40 pulses per second, which were applied for 15 minutes every day during the 12 days. The CON group were not stimulated. The rabbits were sacrificed and the incised wound pans were processed appropriately for the light microscopic examination on the 3rd day, 6th day and 12th day before the beginning of wound treatment. The areas of wound were measured with metric graph paper. The results were as tallows. 1 The PRME and MC group compared with control group showed that wound closure rate increased on 6th, 12th day. 2. It was found that the CON group did not show a complete maturation and had a chronic inflammatory response. Judging from the irregularity of intercellular space and the loose alignment of connective tissue. these findings showed that wound healing was delayed. 3. It showed that inflammatory cells. fibroblasts and epithelial cells activity rapidly processed in the PEME group compared with the CON group. It was found that the PEMI; group showed a advanced remodeling of epithelial layer and a positive repair of connective tissue. 4. It showed that fibroblasts, epithelial cells and inflammatory cells activity rapidly processed in the MC group compared with the CON group. It was found that the MC group showed a improved remodeling of epithelial layer and a dense connective tissue.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• 2006.11a
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• pp.384-389
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• 2006

The needs for Light Railroad Transit(LRT) have been increased due to the heavy traffic congestions in large cities like Seoul, Korea. Korean government is seeking the LRT system development (including planning, designing, construction, and maintenance and operations) in terms of public-private-partnership (PPP). At the private sector side, it is crucial to estimate the life cycle cost (LCC) to project the cash flow during the O&M period. Since the most construction and O&M cost of LRT project is at the bridge construction, a cost analysis model and a cost breakdown structures (CBS) on LRT bridges are discussed through in depth literature reviews. Construction and maintenance cost of bridges are collected and analyzed. LCC is analyzed by types of bridge superstructures and historical data of repair and rehabilitation (R&R) is investigated. There have been scarce number of LCC analysis on railway bridges. This research delivers a well-defined CBS and maintenance cost data, which will be a great benefit to the systematic maintenance strategy development for railroad bridges.

• Korean Journal of Construction Engineering and Management
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• v.13 no.6
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• pp.13-23
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• 2012

While Category 1 and Category 2 bridges are intensively inspected and carefully managed, many small bridges that are not in the Category 1 and 2 are often forgotten until they decay in serious condition. Since many of these small bridges located in the populated city, failure of them would cause huge negative impact on the community. This paper focuses on the small size concrete bridges for timely repair and rehabilitation work for the effective operation and management. Test bed is developed to define the key parameters to forecast the long term performance of the bridges, mostly concrete box bridges. Key parameters suggested in this paper are cumulative fatigue due to repetitive heavy traffic loads and the acid attacks for concrete material deterioration. The cumulative fatigue is measured by the use of the mileage concept. For the long term data collection and inspection, stable and easy to use data collection system is installed as a test bed. The contribution of this research work is on the development of the test bed to define the key parameters of bridge deterioration.