• Current Optics and Photonics
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• 제2권2호
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• pp.119-124
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• 2018

The errors in retrieved aerosol backscattering coefficients due to different lidar ratios are analyzed quantitatively in this paper. The actual calculation shows that the inversion error of the aerosol backscattering coefficients using the Fernald backward-integration method increases with increasing inversion distance. The greater the error in the lidar ratio, the faster the error in the aerosol backscattering coefficient increases. For the same error in lidar ratio, the smaller actual aerosol backscattering coefficient will get the larger relative error of the retrieved aerosol backscattering coefficient. The errors in the lidar ratios for dust or the cirrus layer have great impact on the retrievals of backscattering coefficients. The interval between the retrieved height and the reference range is one of the important factors for the derived error in the aerosol backscattering coefficient, which is revealed quantitatively for the first time in this paper. The conclusions of this article can provide a basis for error estimation in retrieved backscattering coefficients of background aerosols, dust and cirrus layer. The errors in the lidar ratio of an aerosol layer influence the retrievals of backscattering coefficients for the aerosol layer below it.

• 임상간호연구
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• 제25권2호
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• pp.142-150
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• 2019

Purpose: The aim of this study was to evaluate the efficiency of the Humpty Dumpty Falls Scale as one of the falls risk assessment tools, and also to evaluate risk factors as predictors of falls in pediatric patient populations. Methods: In a retrospective, case-control design with data from the electronic medical records of 13 pediatric patients who fell and 1,941 who did not fall before matching and 429 who did not fall after matching by gender, age, diagnosis, and length of stay. Results: All the variables showed no significant differences after matching. At the cutoff score of 13, sensitivity, specificity, negative and positive predictive values were 92.3%, 37.1%, 99.9%, and 0.01%, respectively. The area under the Receiver Operating Characteristics was 0.597. The results from the logistic regression showed that the pediatric inpatient population who had higher risk scores was significantly associated with falls. The odds ratios ranged from 1.31 to 4.71 with 90% confidence interval. Conclusion: The saturation impairments criterion as one of the diagnostic parameter was negatively associated with falls, but the relative risk score was higher than the other criteria. Therefore, it seems that the diagnostic parameter seems to be required to verify results through large sample studies.

• 한국응급구조학회지
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• 제24권3호
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• pp.155-160
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• 2020

Torsades de pointes refers to polymorphic ventricular tachycardia (PMVT), which is caused by the suppression of potassium channels owing to genetic and electrolytic abnormalities, resulting in the extension of the QT interval. Symptoms range from spontaneous circulation recovery to fainting and sudden death. Defibrillation, magnesium correction, and the use of lidocaine as an antiarrhythmic agent are recommended as treatments for persistent torsades de pointes. Currently, only amiodarone is available in the ambulance; however, torsades de pointes does not respond efficiently to amiodarone because it suppresses potassium channels and increases the refractory period of the myocardium. Lidocaine, in contrast, reduces the relative refractory period of the myocardium caused by suppressing sodium channels; thus, it inhibits the occurrence of and treats arrhythmia. In cases where PMVT did not respond to defibrillation, the administration of lidocaine showed no difference in survival and discharge rates compared to amiodarone. Thus, ambulances must be equipped with provisions to administer lidocaine.

• Safety and Health at Work
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• 제13권2호
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• pp.201-206
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• 2022

Background: The present objective was to verify whether burnout (emotional exhaustion [EE], depersonalization [DP] and low professional efficacy [PE]) is a risk factor for long-term sickness absence (LTSA; 30 consecutive days) from the teaching role. Methods: This was a prospective cohort study with two years of follow-up that investigated 509 elementary and high-school teachers. Burnout was identified by Maslach Burnout Inventory. Poisson regression with robust variance was used to adjust for possible confounders. Results: The incidence of LTSA was 9.4%. High EE levels were associated with LTSA in the crude analysis, but the association lost statistical significance after adjustments (for sex, age, perception of work-life balance, general self-rated health, chronic pain and depression). High DP levels were associated with this outcome, even after all adjustments (relative risk = 1.80; 95% confidence interval: 1.05-3.09). Low PE levels were not related to LTSA. Conclusion: The results reinforce the need to improve teachers' work conditions to reduce burnout, particularly DP, and its consequences.

• Smart Structures and Systems
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• 제30권3호
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• pp.245-253
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• 2022

A two-layer beam consisting of an elastoplastic layer and a functional layer made of shape memory alloy (SMA) TiNi is considered. Constitutive relations for SMA are set by a microstructural model capable to calculate strain increment produced by arbitrary increments of stress and temperature. This model exploits the approximation of small strains. The equations to calculate the variations of the strain and the internal variables are based on the experimentally registered temperature kinetics of the martensitic transformations with an account of the crystallographic features of the transformation and the laws of equilibrium thermodynamics. Stress and phase distributions over the beam height are calculated by steps, by solving on each step the boundary-value problem for given increments of the bending moment (or curvature) and the tensile force (or relative elongation). Simplifying Bernoulli's hypotheses are applied. The temperature is considered homogeneous. The first stage of the numerical experiment is modeling of preliminary deformation of the beam by bending or stretching at a temperature corresponding to the martensitic state of the SMA layer. The second stage simulates heating and subsequent cooling across the temperature interval of the martensitic transformation. The curvature variation depends both on the total thickness of the beam and on the ratio of the layer's thicknesses.

• Elastomers and Composites
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• 제57권3호
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• pp.92-99
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• 2022

A large amount of particles on the roads is produced by friction between the vehicles and the road surface and by inflow from outside. The type of these particles affects the abrasion behavior of tire tread. In this study, road dust collected at a bus stop was separated by size, and the particles with sizes of 106-212 mm were analyzed. The particles were separated by density using NaI and NaBr aqueous solutions with densities in the range of 1.10-1.80 g/cm³ with the 0.10 g/cm³ interval. In the road dust sample, the following particle types were found: tire-road wear particles (TRWPs), asphalt pavement wear particles (APWPs), plant-related particles (PRPs), road paint wear particles (RPWPs), and plastic particles (PPs). The densities of TRWPs, APWPs, PRPs, and RPWPs were 1.20-1.80, >1.60, >1.10, and >1.40 g/cm³, respectively, while PPs were found in all density ranges. Additionally, many small mineral particles were observed on the particles. Order of the relative content of the particles was PRP > TRWP > APWP ~ RPWP > PP. APWPs that were stuck to TRWP could be removed by chloroform treatment. The shapes of the particles were characterized using their magnified images.

• Medical Lasers
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• 제10권4호
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• pp.214-219
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• 2021

Background and Objectives To evaluate the difference in near-infrared (810 nm) laser energy transmission through teeth with and without cracks. Materials and Methods Extracted teeth were sectioned and examined visually for the presence of cracks with the aid of photographs and a trans-illuminator. Fourteen sections, each with cracks (Group A) and no cracks (Group B) were identified and placed 15 mm from the tip of a 300 micron fiber, prior to activation with an 810 nm diode laser (0.1W, 50 ms interval,100 ms duration). A power meter positioned behind the tooth recorded the average energy that was transmitted through the samples. Unpaired t-test analysis was used to determine if the tooth sections with cracks allowed higher power passage compared to sound teeth. Results The mean power recording for the cracked teeth (Group A) was significantly greater (p = 0.0005) than that for the non-cracked teeth (Group B). Conclusion Within the limitations of this study, it is evident that significantly higher laser energy passes through teeth with cracks in comparison to teeth without cracks. A recent clinical study has also shown that lasers could be used to assess symptomatic cracked teeth. Hence, further research is required to determine the relative increase in energy required to identify symptomatic cracked teeth.

• Journal of Preventive Medicine and Public Health
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• 제54권4호
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• pp.284-292
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• 2021

Objectives: Low bone density (LBD) in the postmenopausal period has long been a pervasive public health concern; however, the association between parity and LBD has yet to be fully elucidated. Thus, we investigated the association between parity and LBD in postmenopausal Korean women. Methods: This study used baseline data from 1287 Korean postmenopausal women aged 40 years or older enrolled in the Cardiovascular and Metabolic Diseases Etiology Research Center community-based cohort study conducted in Korea from 2013 to 2017. The main exposure was parity (nullipara, 1, 2, 3+). The main outcome was LBD, including osteopenia and osteoporosis, based on bone mineral density measured using quantitative computed tomography of the lumbar spine (L1-2). Results: The mean age of participants was 57.1 years, and the median parity was 2. Of the 1287 participants, 594 (46.2%) had osteopenia and 147 (11.4%) had osteoporosis. No significant difference in the prevalence of LBD was found between nullipara and parous women, whereas higher parity was associated with a higher risk of LBD among parous women; the adjusted odds ratio (95% confidence interval) for the presence of LBD was 1.40 (0.97 to 2.02) for a parity of 2 and 1.95 (1.23 to 3.09) for a parity of 3 relative to a parity of 1. Conclusions: Women who have given birth multiple times may be at greater risk of bone loss after menopause; therefore, they should be a major target population for osteoporosis prevention.

• The Korean Journal of Pain
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• 제36권1호
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• pp.106-112
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• 2023

Background: Most international bodies recommended against musculoskeletal steroid injection during the COVID-19 pandemic, fearing that the immunosuppressive effects of the steroid could worsen COVID-19 infection, thus prolonging the suffering of patients with severe musculoskeletal disease. The authors' aim is to analyze the risk of COVID-19 infection after musculoskeletal injections. Methods: This is a retrospective study of patients who visited a sports medicine clinic and received musculoskeletal steroid injections between January 1, 2020 and February 28, 2021. The collected data was compared with the national COVID-19 registry to identify positive COVID-19 patients. The patients were only considered positive for COVID-19 following corticosteroid injection within 3 months after injection. Results: Out of 502 steroid injections; 79.7% (n = 400) received a single injection in one day, 19.1% (n = 96) received steroid injections at 2 sites in one day, and 1.2% (n = 6) received steroid injections at 3 sites in one day. Using the Fisher's exact test, there was no statistically significant association of COVID-19 infection between the steroid group and control group (relative risk, 1.44; 95% confidence interval, 0.9-23.1, P = 0.654). Only one patient contracted mild COVID-19 with no post COVID complications. Conclusions: The authors recommend the use of musculoskeletal steroid injections in clinically indicated situation without having increased risk of COVID-19.

• Journal of Gastric Cancer
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• 제23권3호
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• pp.428-450
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• 2023

This meta-analysis examined the surgical management of older patients (>80 years) with gastric cancer, who were often excluded from randomized controlled trials. We analyzed 23 retrospective cohort studies involving 18,372 patients and found that older patients had a higher in-hospital mortality rate (relative risk [RR], 3.23; 95% confidence interval [CI], 1.46-7.17; P<0.01) and more post-operative complications (RR, 1.36; 95% CI, 1.19-1.56; P<0.01) than did younger patients. However, the surgical complications were similar between the two groups. Older patients were more likely to undergo less extensive lymph node dissection and longer hospital stays. Although older patients had statistically significant post-operative medical complications, they were not deprived of surgery for gastric cancer. The comorbidities and potential risks of post-operative complications should be carefully evaluated in older patients, highlighting the importance of careful patient selection. Overall, this meta-analysis provides recommendations for the surgical management of older patients with gastric cancer. Careful patient selection and evaluation of comorbidities should be performed to minimize the risk of post-operative complications in older patients, while recognizing that they should not be deprived of surgery for gastric cancer.