• Structural Monitoring and Maintenance
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• 제7권1호
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• pp.1-12
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• 2020

Railway tracks are the direct supporting structures of the trains, which are vulnerable to produce large deformation under the temperature stress or subgrade settlement. The health status of track is critical, and the track should be routinely monitored to improve safety, lower the risk of excess deformation and provide reliable maintenance strategy. In this paper, the distributed optical fiber sensor was proposed to monitor the continuous deformation of the track. In order to validate the feasibility of the monitoring method, two deformation monitoring tests on one steel rail model in laboratory and on one real railway tack in outdoor were conducted respectively. In the model test, the working conditions of simply supported beam and continuous beam in the rail model under several concentrated loads were set to simulate different stress conditions of the real rail, respectively. In order to evaluate the monitoring accuracy, one distributed optical fiber sensor and one fiber Bragg grating (FBG) sensor were installed on the lower surface of the rail model, the strain measured by FBG sensor and the strain calculated from FEA were taken as measurement references. The model test results show that the strain measured by distributed optical fiber sensor has a good agreement with those measured by FBG sensor and FEA. In the outdoor test, the real track suffered from displacement and temperature loads. The distributed optical fiber sensor installed on the rail can monitor the corresponding strain and temperature with a good accuracy.

• Journal of Microbiology and Biotechnology
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• 제24권3호
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• pp.297-312
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• 2014

Food safety is increasingly becoming an important public health issue, as foodborne diseases present a widespread and growing public health problem in both developed and developing countries. The rapid and precise monitoring and detection of foodborne pathogens are some of the most effective ways to control and prevent human foodborne infections. Traditional microbiological detection and identification methods for foodborne pathogens are well known to be time consuming and laborious as they are increasingly being perceived as insufficient to meet the demands of rapid food testing. Recently, various kinds of rapid detection, identification, and monitoring methods have been developed for foodborne pathogens, including nucleic-acid-based methods, immunological methods, and biosensor-based methods, etc. This article reviews the principles, characteristics, and applications of recent rapid detection methods for foodborne pathogens.

• 대한토목학회논문집
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• 제39권4호
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• pp.469-475
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• 2019

구조물의 장기적인 안전관리를 위하여 교량 장기계측시스템이 도입되어 운영 중에 있다. 그러나 일반적인 교량 장기계측시스템은 응답만 측정하고 입력하중은 측정하지 못하고 있기 때문에, 추세분석에 의한 관리기준 상회여부만을 판단하고 있어 정량적인 구조계의 상태평가가 어려운 실정이다. 이러한 단점을 극복하기 위하여 본 논문에서는 도로교 입력하중 측정을 위한 FBG 기반 입력하중 측정센서를 개발하였으며, 실내실험을 통하여 그 타당성을 검증하였다.

• Child Health Nursing Research
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• 제29권3호
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• pp.218-228
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• 2023

Purpose: This study aimed to identify clinical characteristics of South Korean pediatric inflammatory bowel disease (IBD) in a children's hospital over the past 5 years, with a specific focus on comparing the features observed between Crohn's disease (CD) and ulcerative colitis (UC). Additionally, it aimed to examine the nursing diagnoses given to patients. Methods: This retrospective study analyzed the medical records of Korean pediatric patients under 18 years of age who were diagnosed with IBD and hospitalized at a children's hospital in Seoul, South Korea, from January 2017 to December 2021. Results: The number of pediatric patients diagnosed with IBD steadily increased. This finding was particularly prominent for CD patients, the majority of whom were male. Pediatric patients with CD had significantly higher rates of abdominal pain and perianal lesions, while pediatric patients with UC had a higher rate of bloody stool. Laboratory findings indicated that CD patients had higher levels of inflammatory markers and lower albumin levels than UC patients. The nursing diagnoses given during hospitalization mostly related to safety and protection, physical comfort, and gastrointestinal function. Conclusion: This study provides insights into Korean pediatric IBD patients, enabling early detection and the development of nursing intervention strategies. From a comprehensive perspective, nursing care should not only address patients' physical needs but also their psychosocial needs.

• Smart Structures and Systems
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• 제33권3호
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• pp.227-241
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• 2024

Safety and structural integrity of civil structures, like bridges and buildings, can be substantially enhanced by employing appropriate structural health monitoring (SHM) techniques for timely diagnosis of incipient damages. The information gathered from health monitoring of important infrastructure helps in making informed decisions on their maintenance. This ensures smooth, uninterrupted operation of the civil infrastructure and also cuts down the overall maintenance cost. With an early warning system, SHM can protect human life during major structural failures. A real-time online damage localization technique is proposed using only the vibration measurements in this paper. The concept of the 'Degree of Scatter' (DoS) of the vibration measurements is used to generate a spatial profile, and fractal dimension theory is used for damage detection and localization in the proposed two-phase algorithm. Further, it ensures robustness against environmental and operational variability (EoV). The proposed method works only with output-only responses and does not require correlated finite element models. Investigations are carried out to test the presented algorithm, using the synthetic data generated from a simply supported beam, a 25-storey shear building model, and also experimental data obtained from the lab-level experiments on a steel I-beam and a ten-storey framed structure. The investigations suggest that the proposed damage localization algorithm is capable of isolating the influence of the confounding factors associated with EoV while detecting and localizing damage even with noisy measurements.

• 대한임상검사과학회지
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• 제51권1호
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• pp.105-113
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• 2019

본 연구의 목적은 노인성 우울, 노인성 스트레스와 인지기능과의 연관성을 확인하는 것이다. 구체적으로 치매를 유발 원인에 따라 알츠하이머성 치매와 혈관성 치매의 두 그룹으로 분류하고 각 그룹의 인지장애 및 노인성 우울, 노인성 스트레스의 정도와 특성의 차이를 확인하고 상호간의 연관성을 비교하고자 한다. 인지기능의 변수는 한국형 간이정신상태검사, 치매임상평가척도, 이마엽 기능검사, 한국형 도구적 일상생활능력 평가를 사용하였고, 노인성 우울변수는 노인우울척도(GDS), 노인성 스트레스변수는 노인스트레스척도(GSS)를 사용하였다. 통계적 방법은 알츠하이머성 치매환자 80명, 혈관성 치매환자 80명, 통제를 위한 정상군 80명을 설정하여 기술 통계량, Kruskall-Wallis, 상관분석, 다중회귀분석으로 통계적으로 유의한 차이 및 연관성을 확인하였다. 알츠하이머성 치매군에서는 GDS, GSS와 대체적으로 인지기능 변수들과의 상관관계는 확인하였다. 특히 GDS는 남성에서만 인지기능 변수들과 상관관계가 있고, 인지기능 변수들과의 인과관계도 확인되었다. 또한 GSS와 GDS와의 인과관계를 확인하여 GSS가 GDS의 원인이 된다는 유의성을 확인하였다. 결론적으로 GDS는 알츠하이머성 치매군에서 인지기능 변수와의 상관관계와 직접적인 인과관계를 확인하였고, GSS는 직접적인 상관관계보다 GDS를 유발하여 인지기능 장애와의 간접적인 인과관계를 확인할 수 있었다.

• 한국식품위생안전성학회지
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• 제28권2호
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• pp.95-98
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• 2013

Streptococcus suis (S. suis) is a major swine pathogen and an emerging zoonotic agent and is an increasing public health problem across Asia. The present study was undertaken to estimate the antibacterial effect of GR extract and therapeutic effect of GR extract against S. suis infection in mice. At the concentration of GR extract 2.5 mg/ml, the antibacterial effect was not shown on S. suis. However, the antibacterial effect against S. suis was observed at the concentration of GR extract 5.0 mg/ml. Oral administration of GR extract at the dose of 10 mg/kg showed a therapeutic effect for S. suis infected BALB/c mice. The mortality of GR extract-treated mice at the concentration of 5, 10 and 20 mg/kg was 80%, 70%, and 50% at 12 days, respectively, while that of untreated mice was 100% at 8 days after a lethal dose of S. suis infection. The results of our study strongly indicate that GR extract has potential as an effective for S. suis infection in mice.

• 한국산업보건학회지
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• 제24권3호
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• pp.256-262
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• 2014

Objectives: The purpose of this study was to identify the major volatile organic compounds generated during extrusion work with nylon 66 resin and evaluate causes of discomfort among extrusion workers. Methods: A thermal decomposition experiment using nylon 66 resin collected at a worksite was conducted in the laboratory. Based on hazards identified through the thermal decomposition experiment, the exposure levels of the workers were evaluated. Results: The major decomposition products were formaldehyde, acetaldehyde, aniline, cyclopentanone and diphenyl amine. These materials were identical to those sampled in the extrusion booth. The sources of the annoying smells, about which the workers had complained, were formaldehyde, aniline, diphenyl amine, and other hazards in the vapor and fine particles produced by the extrusion work. Formaldehyde, acetaldehyde, and aniline were detected from air samples among workers involved in extrusion work. However, the concentration levels were much lower than Korean occupational exposure limits. The average concentration levels of formaldehyde, acetaldehyde, and aniline were 0.0120 ppm, 0.0036 ppm and 0.0006 ppm, respectively. Conclusions: The extrusion process at around $300^{\circ}C$ thermally decomposes the nylon 66 resin, emitting formaldehyde, aniline, and other hazards, which might have made workers uncomfortable due to their smells. The workers exposure levels to volatile organic compounds were far lower than Korean occupational exposure limits. However, since formaldehyde is a human carcinogen and acetaldehyde and aniline are also confirmed animal carcinogens, it is recommended that exposure levels should be maintained at a minimum level.

• 한국환경교육학회지:환경교육
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• 제2권1호
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• pp.69-83
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• 1991

The management and disposal of harzardous chemicals from the middle school science class was studied for the safety of student and for the protection of the environment. This study was undertaken by analysis of 5 kinks of current middle school science text book and questionnaire survey, and reviewed on the recommended methods for the disposal of harzardous chemical wastes from science class. There are 237 chemicals determined in the middle school science text books and 87 among them actually used in middle school science laboratory. 51 chemicals are classified as harzardous ones and 49 highly hazardous according to the 'Law of Toxic Chemicals management'. 116 chemicals are defined as water pollutants and 10 are highly hazardous water pollutants according to the 'Water Quality Control Law' as well are 91 chemicals as air pollutants and 19 are highly hazardous air pollutants according to the 'Air Quality Control Law' Questionnaire survey results the identification of toxic chemicals, need for education, awareness of toxic effects and current problems in the management. Disposal of toxic chemicals in middle school science class has been undertaken without any treatment, which could be caused of environmental pollution. Most of science teacher wanted to have opportunities to attend supplement courses for the management and disposal of chemicals for the safety and environmental protection. Simple and applicable methods for the management and disposal of chemicals at middle school science level should be strongly recommended to be installed.

• 한국산업보건학회지
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• 제28권3호
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• pp.273-282
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• 2018

Objectives: Dustiness of nanomaterials is considered as exposure index of essential material. Research on dustiness of nanomaterial is needed to control exposure in workplaces. Method: Dustiness measurement using vortex shaker were installed in the laboratory. Nanomaterials, 1 g, was put in the glass test tube and shaked using vortex shaker. Aerosol dispersed was measured using scanning mobility particle sizer(SMPS) and optical particle counter(OPC). Mass concentration using PVC filter and cassette was measured and TEM grid sampling was conducted. Total particle concentration and size distribution were calculated. Image and chemical composition of particles in the air were observed using transmission electron microscopy and energy dispersive X-ray spectrometer. Eleven different test nanomaterials were used in the study. Results: Rank of mass concentration and particle number concentration were coincided in most cases. Rank of nanomateirals with low concentration were not coincided. Two types of fumed silica had the highest mass concentration and particle number concentration. Indium tin oxide, a mixture of indium oxide and tin oxide, had high mass concentration and particle number concentration. Indium oxide had very low mass concentration and particle number concentration. Agglomeration of nanoparticles in the air were observed in TEM analysis and size distribution. In this study, mass concentration and particle number concentration were coincided and two index can be used together. The range of dustiness in particle number concentration were too wide to measure in one method. Conclusion: Particle number concentration ranged from low concentration to high concentration depend on type of nanomaterial, and varied by preparation and amount of nanomaterial used. Further study is needed to measure dustiness of all nanomaterial as one reference method.