• Archives of Plastic Surgery
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• v.36 no.5
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• pp.543-547
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• 2009

Purpose: Adhesion is the most common and troublesome complication after repair of flexor tendon injury. Recently, use of sodium hyaluronate derivatives for adhesion prevention is increasing. A commercial product, Guardix$^{(R)}$, sodium hyaluronate(NaHe) combined with carboxymethylcellulose(CMC) has been newly developed as a preventive material for adhesion. We have investigated its effect in rabbits. Methods: Twenty seven male New Zealand white rabbits were operated under ketamine anesthesia. After tendon repair in zone II of the hind paw, Guardix$^{(R)}$(experimental group) or normal saline(control group) was administered. Biomechanical tests were performed to estimate adhesion formation at 2, 4, 8, and 12 weeks after the operation. Maximum tensile load to flex the distal interphalangeal joint 50 degree from its resting state(MTL50) was measured, depicting the amount of adhesion formed. Subsequently, breaking strength was assessed. Results: There were no postoperative complications such as infection, wound dehiscence, or hematoma. MTL50 was significantly lower in the experimental group than in the control group at 4, 8, 12 weeks (p<0.05). Mean value of MTL50 was 6.64N in the experimental group and 28.53N in the control group at 12 weeks after surgery. There were no significant differences in breaking strength. Conclusion: Our results indicate that Guardix$^{(R)}$ is helpful in reducing adhesion formation and does not interfere with normal healing processes of the tendon.

• Journal of the Korea institute for structural maintenance and inspection
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• v.20 no.6
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• pp.1-9
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• 2016

The paper aims at evaluating effects of preventive maintenance on life cycle cost(LCC) reduction of bridges. The preventive maintenance activities capable to delay bridge deteriorations can reduce overall maintenance costs and extend service life of a bridge by regularly providing maintenance activities and avoiding larger maintenance(repairs or rehabilitations) costs. Couple of prediction models were proposed in order to calculate LCC of a typical bridge: a health score model and repair rehabilitation cost model. In addition, the maintenance activities such as wash and painting were also suggested in order to consider effects of preventive maintenance in the analysis based on literature reviews. According to analysis results, new maintenance strategy(reactive maintenance + preventive maintenance) can save \0.5 billion per bridge for future life-cycle costs over 100 year analysis or \184 billion for entire HBMS(Highway Bridge Management System) inventory over 20 years. Small investments for preventive maintenance in improved bridge management can have a very significant return when considering the large bridge inventory.

• Journal of the Korean Society of Safety
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• v.30 no.3
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• pp.13-19
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• 2015

Railway vehicle equipment goes back again to the state just before when failure by the repair. In repairable system, we are interested in the failure interval. As such, a statistical model of the point process, NHPP power law is often used for the reliability analysis of a repairable system. In order to derive a quantitative reliability value of repairable system, we analyze the failure data of the air brake system of the train line 7. The quantitative value is the failure intensity function that was modified, converted into a cost-rate function. Finally we studied the optimal number and optimal interval in which the costs to a minimum consumption point as cost-rate function. The minimum cost point was 194,613 (won/day) during the total life cycle of the braking system, then the optimal interval were 2,251days and the number of optimal preventive maintenance were 7 times. Additionally, we were compared to the cost of a currently fixed interval(4Y) and the optimum interval then the optimal interval is 3,853(won/day) consuming smaller. In addition, judging from the total life, "fixed interval" is smaller than 1,157 days as "optimal interval".

• Journal of Energy Engineering
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• v.20 no.2
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• pp.154-162
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• 2011

PMT(Preventive Maintenance Template) is a standardized maintenance program that describes maintenance items & period as operation condition to increase component reliability at the component level. The existing maintenance programs are focused on time based maintenance to inspect and repair component depend on fixed period. But recently, we have developed advanced maintenance program(named PMT) to increase reliability and optimize maintenance program of the plant significant component. This paper presents how to develop the PMT for nuclear power plant's static exciter.

• Journal of Applied Reliability
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• v.17 no.2
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• pp.159-167
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• 2017

Purpose: The purpose of this research is to study research trend in the field of warranty and maintenance policy of second-hand products. Methods: To this end, we consider research articles, which deal with warranty and maintenance of the second-hand products, published on journals during the past 20 years and classify them by taxonomy scheme proposed by Shafiee and Chukova (2013). The taxonomy scheme consists of three maintenance models in warranty for second-hand product. In each models, we analyze proposed maintenance and warranty policies with respect to types of upgrade models, types of preventive maintenances, decision variables and decision criteria model. Results: We obtain the scheme of maintenance and warranty of the second-hand products and define cost related to warranty and maintenance of the second-hand item. Also, we summarize the characteristics of maintenance and warranty policies in each classified model. Conclusion: There have been several research reviews on maintenance and warranty polity of new products. This research surveys researches of authors during the past 20 years and classifies, summarizes and compares proposed maintenance and warranty policies of the second-hand products. This research provides useful information to researchers who are interested in maintenance and warranty of the second-hand products.

• Journal of Preventive Medicine and Public Health
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• v.52 no.5
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• pp.292-298
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• 2019

Objectives: Presenteeism is currently recognized as a significant global health issue that can potentially cause productivity losses. Hence, many studies have analyzed the relationships between workplace factors and presenteeism. However, few studies have considered non-occupational factors. This study examined the associations between presenteeism and activities outside work, including volunteering, self-development, leisure/sports, and gardening and house repair activities, in Korean wage workers. Methods: This study analyzed the fourth Korean Working Conditions Survey, in which a total of 19 294 wage workers participated. To identify relationships between presenteeism and activities outside work, multivariate logistic regression analysis was used after adjusting for general and occupational characteristics. Results: Self-development and leisure/sports activities significantly increased the odds ratio (OR) of presenteeism (OR, 1.166; 95% confidence interval [CI], 1.061 to 1.282 and OR, 1.276; 95% CI, 1.181 to 1.379, respectively). Conclusions: Certain activities outside work, such as self-development or leisure/sports, were related to presenteeism among Korean wage workers. Although many previous studies have emphasized the positive effects of those activities on health, this study documented negative effects of these activities outside work on health.

• Asian Pacific Journal of Cancer Prevention
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• v.13 no.2
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• pp.621-623
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• 2012

To estimate the genetic susceptibility for childhood lymphoma, we conducted an association study for 23 cases and 148 controls. Total 1536 tag single nucleotide polymorphisms (SNPs) were selected in 138 candidate gene regions related to immune responses, apoptosis, the cell cycle, and DNA repair. Twelve SNPs were significantly associated with the risk of lymphoma ($P_{trend}$ <0.05) in six genes ($IL1RN$, $IL2$, $IL12RB1$, $JAK3$, $TNFRSF13B$, and $XRCC3$). The most significant association was seen for $IL2$ variant rs2069762 ($OR_{TG+GG}$ vs. TT=3.43 (1.29-9.11), $P_{trend}$=0.002, min$P$=0.005). These findings suggest that common genetic variants in $IL2$ might play a role in the pathogenesis of childhood lymphoma.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.41
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• pp.5.1-5.5
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• 2019

Background: The present study aimed to determine whether laypeople and professionals rate the facial appearance of individuals with repaired complete unilateral or bilateral cleft lip and palate (UCLP, BCLP) similarly based on viewing full facial images. Methods: The study followed a cross-sectional analytical design where five young patients aged 10 to 14 years, who had completed all stages of their unilateral or bilateral cleft lip and palate treatment (bilateral: three, unilateral: two), were evaluated by two groups. The assessment was done by laypeople and 97 qualified professionals (33 orthodontists, 32 plastic surgeons, and 32 oral and maxillofacial surgeons). Professionals were not involved in any stage of the patients' treatment. Results: The facial appearance assessment of the professional groups on different facial aesthetics was significantly lower than that of laypeople, and they had higher perceived need for further treatment. On the other hand, laypeople had higher aesthetic ratings and lower perceived need for further treatment. Differences were also observed between the assessments of the professional groups. Participants who had lower aesthetic assessments of the repair tended to report a higher influence of cleft lip and palate on social activities and professional life. Conclusion: Differences in perception exist between healthcare professionals and laypeople. The discrepancies between the professional groups could be attributed to different treatment modalities and protocols.

• Journal of Korean Society for Quality Management
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• v.21 no.2
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• pp.109-120
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• 1993

Most systems are composed of components which have different failure chracteristics. Since the failure characteristics of components is different, it is rational and reasonable to establish a maintenance model to be considered repair and replacement policies which are proper to failure characteristics of these components. This paper proposes the age replacement time for a system composed of components which have different failure characteristics. In this model, it is assumed that a system is composed of a critical failure component, a major failure component, minor failure component. If any failure occurs to critical component before its age replacement time, the system should be replaced. If any failure does not occur until its age replacement time, preventive replacement should be performed at age replacement time T. Major component is minimal repaired if any failure occurs during operation. Minor component should be replaced as soon as failure is found. This paper determines the optimal replacement time of the system which minimize, total maintenance cost and initial stock Quantity of minor component within this optimal replacement time. Numerical example illustrates these results.

• Proceedings of the Korea Concrete Institute Conference
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• 2001.11a
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• pp.1185-1192
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• 2001

This paper reviews available techniques for monitoring corrosion of steel in concrete. The need for early detection and diagnosis of corrosion related deterioration in reinforced structures is widely acknowledged. This is particularly important in reinforced concrete structures on account of the economic and social significance of the problem. The current generally used on-site procedure for corrosion monitoring of reinforced structures employs a method of half-cell surface potential measurements. While the technique has provided a useful means of delineating areas of high or low corrosion risk, there are difficulties in its use and interpretation when assessing rates of deterioration. Electrochemical techniques are by far the most suitable for corrosion monitoring purpose and meet most of the requirements. The aim of this paper is to describe the electric resistance sensor(ER sensor) and electrochemical techniques employed to monitor and estimate corrosion rates of reinforcement. Early detection and diagnosis of corrosion hazards allows preventive measures to be taken, hence the typically expensive repair of severely deteriorated structures can be avoided.