• Safety and Health at Work
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• v.11 no.2
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• pp.199-206
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• 2020

Background: In a wide range of industries, noise-induced hearing loss remains one of the most prevalent occupational problems. This study aimed to assess the noise exposure level and associated factors of hearing loss among textile workers in Yangon Region, Myanmar. Methods: A cross-sectional study was conducted at a Textile mill (Thamine), Yangon Region, from April to December 2018. In total, 226 workers who were randomly selected from 3 weaving sections participated in face-to-face interviews using a structured questionnaire. A digital sound level meter and pure-tone audiometer were used for the assessment of noise exposure level and hearing loss, respectively. Logistic regression analysis was performed to assess the associated factors of hearing loss. Results: In total workers, 66.4% were exposed to ≥85 dB(A) of noise exposure, and the prevalence of hearing loss was 25.7%. Age ≥35 years, below high school education, hearing difficulty, tinnitus, hypertension, > 9 years of service duration in a textile mill were positively associated with hearing loss. After adjusting confounding factors, age ≥35 years (adjusted odds ratio = 6.90, 95% confidence interval = 3.45-13.82) and tinnitus (adjusted odds ratio = 2.88, 95% confidence interval = 1.13-7.37) were persistently associated with hearing loss. Conclusion: Providing occupational hazard education and enforcement of occupational safety regulations should be taken to decrease the noise exposure level. The regular audiometry test should be conducted for assessment of hearing threshold shift. The employer needs to implement a hearing conservation program in workplace when noise exposure reaches or exceeds 85 dB(A) for 8 hours.

• Structural Engineering and Mechanics
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• v.53 no.2
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• pp.311-324
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• 2015

The purpose of this study was to investigate experimentally the fatigue performance of reinforced concrete (RC) beams with hot-rolled ribbed fine-grained steel bars of yielding strength 500MPa (HRBF500). Three rectangular and three T-section RC beams with HRBF500 bars were constructed and tested under static and constant-amplitude cyclic loading. Prior to the application of repeated loading, all beams were initially cracked under static loading. The major test variables were the steel ratio, cross-sectional shape and stress range. The stress evolution of HRBF500 bars, the information about crack growth and the deflection developments of test beams were presented and analyzed. Rapid increases in deflections and tension steel stress occured in the early stages of fatigue loading, and were followed by a relatively stable period. Test results indicate that, the concrete beams reinforced with appropriate amount of HRBF500 bars can survive 2.5 million cycles of constant-amplitude cyclic loading with no apparent signs of damage, on condition that the initial extreme tensile stress in HRBF500 steel bars was controlled less than 150 MPa. It was also found that, the initial extreme tension steel stress, stress range, and steel ratio were the main factors that affected the fatigue properties of RC beams with HRBF500 bars, whose effects on fatigue properties were fully discussed in this paper, while the cross-sectional shape had no significant influence in fatigue properties. The results provide important guidance for the fatigue design of concrete beams reinforced with HRBF500 steel bars.

• Journal of the Korean Institute of Gas
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• v.19 no.4
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• pp.55-61
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• 2015

In this paper, the displacement behavior characteristic of hollow rollers with various cross sectional area profiles and circular plate for load supporting capacity increment has been presented using a finite element method. The FEM results present that the hollow roller with X-shaped or Y-shaped columns between outer tube, middle tube and inner tube reduces a maximum displacement at the middle length of hollow rollers. And the circular plate, which is inserted at the middle of the hollow roller, is very useful to reduce the maximum displacement of hollow rollers with the plate thickness of 30~40mm. This paper presents the weight vs the maximum displacement ratio in which is represented for the optimized design as a function of a hollow roller total weight. The FEM analyzed results recommend the design model 4, 5 and 6 of hollow rollers for decreasing the ratio of maximum displacement and total weight of hollow rollers.

• Journal of Preventive Medicine and Public Health
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• v.26 no.2 s.42
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• pp.179-191
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• 1993

Generally fatty liver is attributed either to chronic alcoholism, diabetes mellitus, or obesity. Based upon this commonly held clinical brief, this study was conducted to investigate the contributing factors of fatty liver and odds ratio (OR) of known contributing factors. A sample of 310 male participants, who visited at Seoul Paik Automated Multiphasic Health Testing System from November 1991 to December 1991, was separated into 112 cases and 198 controls by ultrasonographic fin ding. There were statistically significant difference between fatty liver and normal in triglyceride (TG), body mass index (BMI), alanine aminotransferase (ALT), high density lipoprotein cholesterol (HDL-C), fasting blood sugar (FBS), alcohol consumption, low density lipoprotein cholesterol (LDL-C), total cholesterol, gamma-glutamyl transferase ($\gamma$-GT), duration of alcohol intake and alkaline phosphatase (Alk.P)(P<0.01, P<0.05). The statistically significant elevated odds ratio were noted for TG (4.48, confidence interval (CI) 2.66-7.55, P=0.000), alcohol consumption(3.24, CI 1.56-6.23, P=0.002), BMI(3.05, CI 1.87-4.97, P=0.000), and FBS (2.59, CI 1.53-4.40, P=0,000). In summary, it is suggested that the fatty liver could be preventive by avoiding such deleterious factors as high fat diet, alcohol and obesity.

• Journal of the Korea institute for structural maintenance and inspection
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• v.26 no.5
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• pp.66-73
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• 2022

In this study, the experimental results of 7 dampers with the same strut height and similar cross-sectional area were compared based on the existing research results on steel dampers with rocking behavior. As steel plate dampers, SI-260, SV-260, SS-260 without Lateral deformation prevention detail(Ldpd), I-1, V-1, S-1 with Ldpd, and R20-260 with steel rod damper were evaluated. In addition, R15-260, which has a cross-sectional area of 0.56 times than other dampers, was also reviewed to appropriately evaluate the behavior of the steel rod damper. An important study result is the application superiority of the steel rod damper, which improved the unidirectional behavior of the steel plate dampers. This was proved in the moment-resistance capacity and displacement ratio evaluation. As a result of the evaluation, the R20-260, a steel bar damper, was evaluated as having the best performance. In addition, it is judged to have sufficient seismic resistance as it shows deformability up to a displacement ratio of 2.0.

• Journal of the Society of Disaster Information
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• v.19 no.4
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• pp.851-858
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• 2023

Purpose: A study was conducted to ensure the structural safety of a raised girder bridge with improved cross-sectional efficiency compared to the conventional PSC girder. For this purpose, the cross-sectional specifications such as girder length, height, and width were determined, the arrangement of the tendons was designed, and the practical performance of the raised girder under static and dynamic loads was verified. Method: The static performance experiment examined the serviceability limit state by measuring behavioral responses such as deflection and cracking to primary and secondary static loads. In addition, the dynamic load loading experiment measured the acceleration and displacement behavior response over time to calculate the natural frequency and damping ratio to examine the usability limit state. Result: As a result of the static performance test, the deflection value based on the maximum applied load showed stable behavior, and the crack width measured at the maximum applied load level was very small, satisfying the serviceability limit state. In addition, a natural frequency exceeding the natural frequency calculated during the design of the dynamic loading experiment was found, and a damping ratio that satisfies the current regulations was found to be secured.

• Clinical Nutrition Research
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• v.13 no.1
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• pp.51-60
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• 2024

Obesity and overweight pose a significant public health problem, as they are associated with an elevated risk of metabolic syndrome (MetS). Several studies have shown that diet quality is associated with the development of MetS risk factors. Analyzing dietary patterns may be more helpful in determining the relationship between eating habits and chronic diseases compared to focusing on single foods or nutrients. In this study, our objective was to evaluate the association of food quality score (FQS) with risk factors for MetS in individuals with obesity and overweight. The participants in this cross-sectional study were 340 adults with overweight and obesity. Participants' food intake was measured using a Food Frequency Questionnaire, then the FQS was calculated. A fasting blood sample assessed serum glucose, triglycerides, total cholesterol (TC), high-density lipoprotein cholesterol, and serum insulin levels. Fat-free mass, height, basal metabolic rate, socio-economic score, and waist-to-hip ratio significantly differed among FQS tertiles. TC, systolic and diastolic blood pressure, and fasting blood glucose were significantly lower in the highest tertile of FQS. After multivariable adjustment, our results showed that individuals in the third tertile of FQS had reduced risk of higher levels of TC (odds ratio [OR], 0.982; 95% confidence interval [CI], 0.970-0.984) and higher levels of low-density lipoprotein cholesterol (OR, 0.974; 95% CI, 0.974-0.999). Our findings demonstrate an inverse relationship between diet quality, as measured by FQS, and MetS risk factors. However, further experimental and longitudinal investigations are warranted to elucidate the causal nature of this association.

• Safety and Health at Work
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• v.15 no.2
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• pp.187-191
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• 2024

Background: Effective near-miss management is important in preventing workplace accidents. A company's inadequate response to near-miss reports can lead workers to feel insecure and dissatisfied with the company. We investigated the relationship between companies' responses to near-miss reports and turnover intentions of workers. Methods: We conducted a cross-sectional study using online self-administered questionnaire survey to workers aged ≥20 years in Japan in March 2022. The analysis included 5,071 participants who had nearmiss experiences and reported them to their companies. The independent variable was companies' responses to near-miss reports, classified into three categories: adequate response group, inadequate response group, and no response group. The dependent variable was turnover intentions. We calculated the odds ratio and 95% confidential interval (CI) using multilevel logistic regression analyses nested for industries and adjusted for covariates. Results: Of the 5,071 participants, 3,058 (60.3%) were adequate response group, 1,484 (29.3%) were inadequate response group, and 529 (10.4%) were no response group. In multivariable adjusted model, compared with adequate response group, the odds ratio of inadequate response group and no response group were 1.80 (95% CI: 1.56-2.08) and 2.63 (95% CI: 2.15-3.22), respectively. Conclusion: Our results suggested that there was a relationship between companies' responses to the near-miss reports and turnover intentions of workers. It is important not only to collect near-misses but also to respond appropriately to the reports and provide feedback to workers.

• The korean journal of orthodontics
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• v.54 no.5
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• pp.325-341
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• 2024

Objective: To correlate temporomandibular joint (TMJ) morphology and position with cone-beam computed tomography (CBCT) images, Joint Vibration Analysis (JVA), and Jaw Tracker (JT) to develop a radiation-free, dynamic method for screening and monitoring the TMJ in orthodontic patients. Methods: A total of 236 orthodontic patients without symptoms of TMJ disorders who had undergone CBCT were selected for the JVA and JT tests in this cross-sectional study. TMJ position and morphology were measured using a three-dimensional analysis software. JT measurements involved six opening-closing cycles, and JVA measurements were performed using a metronome to guide the mouth opening-closing movements of the patients. The correlations among the three measuring devices were evaluated. Results: Abnormalities in condylar surface morphology affected the mandibular range of motion. The cut-off value results show that when various measurement groups are within a certain range, abnormalities may be observed in morphology (area under the curve, 0.81; P < 0.001). A 300/< 300 Hz ratio ≥ 0.09 suggested abnormal morphology (P < 0.05). Correlations were observed among the maximum opening velocity, maximum vertical opening position, and joint spaces in the JT measurements. Correlations were also observed between the > 300/< 300 Hz ratio, median frequency, total integral, integral < 300 Hz, and peak frequency with joint spaces in the JVA measurements. Conclusions: JT and JVA may serve as rapid, non-invasive, and radiation-free dynamic diagnostic tools for monitoring and screening TMJ abnormalities before and during orthodontic treatment.

• Restorative Dentistry and Endodontics
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• v.30 no.4
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• pp.327-334
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• 2005

This study investigated the effect of anticurvature filing method on preparation of the curved root canal using ProFile. Thirty six resin blocks were divided equally into three groups by instrumentation motions: anticurvature filing motion. circumferential filing motion and straight up-and-down motion. Each resin block was sectioned at 8mm level from the apex and at the greatest curvature of the canal and reassembled in metal mold by a modified Bramante technique. All groups were instrumented with the ProFile system. At each levels. image of sectioned surface were taken using CCD camera under a stereomicroscope at $\times40$ magnification and stored. Distances of transportation at the inner and outer area of curvature and the centering ratio were determined and compared by statistical analysis. along with the assessment of the increase of root canal cross-sectional area. The results were as follows; 1. In all groups. there was no statistical difference in the mean increase of root canal cross-sectional area. the centering ratio. and the mean distances of transportation at the inner area of curvature at each level. 2. At 8mm level from the apex. the mean distances of transportation at the outer area of curvature decreases in following order anticurvature filing motion. circumferential filing motion. straight up-and­down motion but. no significant difference at the greatest curvature of the canal among three groups. Effect of anticurvature filing motion using ProFile does not seem to be different from other instrumentation motions at the inner area of curvature in curved root canal.