• Clinics in Shoulder and Elbow
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• v.24 no.3
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• pp.123-124
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• 2021

• Journal of the Korean Society of Hazard Mitigation
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• v.7 no.3
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• pp.33-39
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• 2007

This paper presents a detailed experimental study on the engineering and durability properties of nano mixed inorganic repair material with rehabilitation and enhancement of performance of concrete structure occur to crack. The performance of specimens was evaluated using bond strength, chloride ion ingress, carbonation and brine resistance. It was shown in the results of the experiments that it had a superior function in the bond strength under the standard and wet-dry condition of all the repair material. Moreover, it had a good function in the experiments for chloride ion ingress, carbonation and brine resistance. Judging from the above-mentioned results, it is expected to be used for the rehabilitation and enhancement of the performance of concrete structure.

• Computers and Concrete
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• v.19 no.4
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• pp.413-417
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• 2017

Concrete is a material popularly used in construction. Due to the load-bearing and external environmental factors during utilization or manufacturing, its surface is prone to flaws, such as crack and leak. To repair these superficial defects and ultimately and avoid the deterioration of the concrete's durability, numerous concrete surface protective coatings and crack repair products have been developed. Currently, studies are endeavoring to exploit the mineralization property of microbial strains for repairing concrete cracks be the repairing material for crack rehabilitation. This research aims to use bacteria, specifically B. pasteurii, in crack rehabilitation to enhance the flexural and compression strength of the repaired concrete. Serial tests at various bacterial concentrations and the same $Urea-CaCl_2$ medium concentration of 70% for crack rehabilitation were executed. The results prove that the higher the concentration of the bacterial broth, the greater the amount of calcium carbonate precipitate was induced, while using B. pasteurii broth was for crack rehabilitation. The flexural and compression strengths of the repaired concrete test samples were the greatest at 100% bacterial concentration. Compared to the control group (bacterial concentration of 0%), the flexural strength had increased by 32.58% for 1-mm crack samples and 51.01% for 2-mm crack samples, and the compression strength had increased by 28.58% and 23.85%, respectively. From the SEM and XRD test results, a greater quantity of rectangular and polygonal crystals was also found in samples with high bacterial concentrations. These tests all confirm that using bacteria in crack rehabilitation can increase the flexural and compression strength of the repaired concrete.

• Proceedings of the Korea Concrete Institute Conference
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• 1997.10a
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• pp.89-94
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• 1997

As the reinforced concrete structures are aged, repair and rehabilitation materials and techniques have ben developed. However, most of the repair materials and methods are imported from abroad and theoretical study and repairing techniques are also not well established yet. A specification for quality of repair materials should be established, in order to secure the stability and to improve the serviceability of the repaired structures. In this study, long term properties of repair materials such as thermal expansion coefficient, hardening shrinkage, creep, and chemical resistance have been tested. The material properties shows to be affected many actors such as curing period, temperatures, relative humidity, and etc. The repair material should be selected by considering the cause and shape of the defects, mix properties, workability, quality control of construction, and etc.

• Clinics in Shoulder and Elbow
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• v.19 no.1
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• pp.51-58
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• 2016

The arthroscopic rotator cuff repair is now considered a mainstream technique with highly satisfactory clinical results. However, concerns remain regarding healing failures for large and massive tears and high revision rate. In recent decades, various repair strategies and construct configurations have been developed for rotator cuff repair with the understanding that many factors contribute to the structural integrity of the repaired construct. The focus of biomechanical test in arthroscopic repair has been on increasing fixation strength and restoration of the footprint contact characteristics to provide early rehabilitation and improve healing. These include repaired rotator cuff tendon-footprint motion, increased tendon-footprint contact area and pressure, and tissue quality of tendon and bone. Recent studies have shown that a transosseous tunnel technique provides improved contact area and pressure between rotator cuff tendon and insertion footprint, and the technique of using double rows of suture anchors to recreate the native footprint attachment has been recently described. The transosseous equivalent suture bridge technique has the highest contact pressure and fixation force. In this review, the biomechanical tests about repair techniques of rotator cuff tear will be reviewed and discussed.

• Proceedings of the Korea Concrete Institute Conference
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• 2000.04a
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• pp.458-463
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• 2000

Recently, there are increasing much concerns about repair and rehabilitation works for aged Concrete Structures which had been constructed on around the 1970's for rapid economic growth in Korea. In particular, it is believed that there are many aged concrete slabs for Highway bridges in these days. Thus new construction method of concrete slabs are strongly needed to minimize the traffic congestion during the repair works. The objective of this research is to develop the new constructional method of concrete slab in bridge structure, which can contribute to minimize the traffic congestion to be occurred during the repair and rehabilitation works of aged concrete slab, and can also assure the reliable quality through the minimization of in-situ works at the site. I-beams with punch holes will be manufactured in accordance with the specification in the factory, and will be preassembled into the panel. After erecting the preassembled panels in the site, concrete will be poured into the slab panel. This research is to investigate physical properties of I-Beam with punch holes itself, and then to investigate structural properties of assembled I-Beam panels through static and fatigue test, of which result can be utilized for the development of the new constructional method for concrete slab in bridge structure.

• Journal of the Korean Society of Industry Convergence
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• v.24 no.6_2
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• pp.861-872
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• 2021

An efficient cost management is important for the domestic social overhead capital(SOC) based on a long lifecycle after 30 years since completion. Maintenance in South Korea have had the restrictions of consistency and suitability of decision-making by the establishment of a budget plan based on the company estimate and repair and reinforcement methods determined by the inspection and diagnosis engineers' subjective determination for each facility. To resolve this issue, the Korea Institute of Civil Engineering and Building Technology is currently in development of a methodology to propose an optimum maintenance method according to the damage of components by artificial intelligence. This study has deduced the primary factors by analyzing information generated during bridge maintenance and management as a prior step for the development of technologies, and conducted a preliminary analysis to select the optimum artificial intelligence technology.

• The Korean Journal of Pain
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• v.33 no.4
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• pp.344-351
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• 2020

Background: The effects of far-infrared radiation (FIR) on the treatment of rotator cuff diseases remains unknown. We evaluated the safety and efficacy of FIR after arthroscopic rotator cuff repair with regard to postoperative pain and healing. Methods: This prospective randomized comparative study included 38 patients who underwent arthroscopic rotator cuff repair due to a medium-sized tear. Patients were randomly divided into the FIR or control group (n = 19 per group). In the FIR group, FIR with an FIR radiator started 1 week postoperatively for 30 minutes per session twice daily. It lasted until abduction brace weaning at 5 weeks postoperatively. We assessed pain using a pain visual analogue scale (pVAS) and measured the range of motion (ROM) of the shoulder at 5 weeks, and 3 and 6 months, postoperatively. The anatomical outcome was evaluated using magnetic resonance imaging at 6 months postoperatively. Results: At 5 weeks postoperatively, the average pVAS score was lower in the FIR group than in the control group (1.5 ± 0.8 vs. 2.7 ± 1.7; P = 0.019). At 3 months postoperatively, the average forward flexion was higher in the FIR group (151.6° ± 15.3° vs. 132.9° ± 27.8°; P = 0.045), but there was no significant difference at 6 months postoperatively. There was no significant difference in healing failure between the groups (P = 0.999). Conclusions: FIR after arthroscopic rotator cuff repair could be an effective and safe procedure to reduce postoperative pain, thereby facilitating rehabilitation and better ROM in the early postoperative period.

• Physical Therapy Korea
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• v.5 no.3
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• pp.34-41
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• 1998

Noninvasive low intensity ultrasound has been shown to be an effective means of accelerating bone fracture repair in both animal and clinical studies. The effects of ultrasound stimulation on bone repair after fibular osteotomy were assessed in a rabbit fibular fracture model. Bilateral closed fibular fractures were made in skeletally mature male White Japanese rabbits. In this study, 24 subjects were randomly divided into 2 groups: experimental group 1 (n=12), and experimental group 2 (n=12). Experimental group 1 received 0.875 MHz continuous ultrasound and Experimental group 2 was treated with 3 MHz continuous u1trasound. The ultrasound intensity was 50 $mW/cm^2$ and treatment time was 10 minutes for every session in both groups. In each rabbit, one fibula served as a control and the other was subjected to ultrasound treatment 5 times per week for 3 weeks. After 3 weeks, rabbits were sacrificed and the ratios of the area between the trabeculae and bone marrow of the fibulae were calculated. At the end of the experimental period, 14 of the 24 rabbits were excluded due to complications from surgery or inadequate fracture status for this study. There was no statistically significant difference in the trabeculae area between experimental leg and control leg in experimental group 1 and experimental group 2 (p>0.05). And there was also no statistic-statistically significant difference between experimental group 1 and experimental group 2 according to ultrasound treatment frequencies, 0.875 MHz and 3 MHz (p>0.05). These data suggest that in Japanese white rabbits, low intensity ultrasound stimulation does not facilitate fracture repair nor is there any difference in fracture repair results between ultrasound frequencies, 0.875 MHz and 3 MHz.

• Clinics in Shoulder and Elbow
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• v.17 no.2
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• pp.57-63
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• 2014

Background: To compare the effect of different starting periods of rehabilitative exercise (early or delayed passive exercise) on the rate of retear and other clinical outcomes after the arthroscopic repair of the rotator cuff. Methods: In total, 103 patients who underwent arthroscopic repair of the rotator cuff were included in the study. Determined at 2 weeks post-operation, patients who were incapable of passive forward elevation greater than $90^{\circ}$ were allotted to the early exercise group (group I: 79 patients; 42 males, 37 females), whilst those capable were allotted to the delayed exercise group (group II: 24 patients; 14 males, 10 females). The group I started passive exercise, i.e. stretching, within 2 weeks of operation, whilst group II started within 6 weeks. The results were compared on average 15.8 months (11-49 months) post-operation using the passive range of motion, the Visual Analog Scale (VAS) pain score, and the University of California at Los Angeles (UCLA) and Constant scores. Stiffness was defined as passive forward elevation or external rotation of less than $30^{\circ}C$ compared to the contralateral side. Follow-up magnetic resonance imaging (MRI) was carried out on average 1 year post-operation and the rate of retear was compared with Sugaya's criteria. Results: There were no differences between the two groups in gender, age, smoking, presence of diabetes, arm dominance, period of tear unattended, pre-operative range of motion, shape and size of tear, degree of tendon retraction, and tendon quality. There were no significant differences in clinical outcomes. Whilst stiffness was more frequent in group II (p-value 0.03), retear was more frequent in group I (p-value 0.028) according to the MRI follow-up. Conclusions: During rehabilitation after the arthroscopic repair of the rotator cuff, the delay of passive exercise seems to decrease the rate of retear but increase the risk of stiffness.