• Annals of Rehabilitation Medicine
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• v.39 no.6
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• pp.897-904
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• 2015

Objective To investigate differences in plantar pressure distribution between a normal gait and unpredictable slip events to predict the initiation of the slipping process. Methods Eleven male participants were enrolled. Subjects walked onto a wooden tile, and two layers of oily vinyl sheet were placed on the expected spot of the 4th step to induce a slip. An insole pressure-measuring system was used to monitor plantar pressure distribution. This system measured plantar pressure in four regions (the toes, metatarsal head, arch, and heel) for three events: the step during normal gait; the recovered step, when the subject recovered from a slip; and the uncorrected, harmful slipped step. Four variables were analyzed: peak pressure (PP), contact time (CT), the pressure-time integral (PTI), and the instant of peak pressure (IPP). Results The plantar pressure pattern in the heel was unique, as compared with other parts of the sole. In the heel, PP, CT, and PTI values were high in slipped and recovered steps compared with normal steps. The IPP differed markedly among the three steps. The IPPs in the heel for the three events were, in descending order (from latest to earliest), slipped, recovered, and normal steps, whereas in the other regions the order was normal, recovered, and slipped steps. Finally, the metatarsal head-to-heel IPP ratios for the normal, recovered, and slipped steps were $6.1{\pm}2.9$, $3.1{\pm}3.0$, and $2.2{\pm}2.5$, respectively. Conclusion A distinctive plantar pressure pattern in the heel might be useful for early detection of a slip event to prevent slip-related injuries.

• Archives of Craniofacial Surgery
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• v.22 no.2
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• pp.99-104
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• 2021

Background: To fight the coronavirus disease 2019 (COVID-19) pandemic, many countries have implemented social distancing and lockdowns. We investigated the changes in the trauma patterns of emergency plastic surgeries in the midst of a pandemic. Methods: A retrospective review of the medical records of all patients treated for emergency plastic surgeries was performed at our hospital in Seoul. We conducted the analysis between March 1 and June 30, 2020, and compared the data obtained with that of the same period in 2019. We also investigated changes in trauma patterns according to the social distancing level from July 2020 to February 2021. Results: There was a total of 800 emergency plastic surgery patients from March to June 2020, which was less than the 981 in the corresponding period in 2019. The proportion of patients aged 7-17 years and ≥ 80 in 2020 showed a significant decrease. In 2020, patients presenting with facial trauma decreased and hand trauma, markedly laceration, increased significantly. In 2020, more injuries happened at home, whereas significantly fewer injuries happened on the streets. In 2020, slipping and sports injury decreased, whereas penetrating injury increased significantly. In the changes observed according to the social distancing level, there were significant differences in age classification, facial open wound, and the mechanism of injury. Conclusion: Social distancing has caused a change in emergency plastic surgeries. To ensure safe and appropriate treatment, strict epidemiologic workup and protective equipment are required.

• Tribology and Lubricants
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• v.35 no.1
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• pp.59-64
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• 2019

When slipping occurs between two materials, the coefficients of friction must be considered because these values determine the overall efficiency of the machine or slip characteristics. Therefore, it is important to find the coefficient of friction between two materials. This paper focuses on obtaining the coefficient of friction between an aiming bolt and a retainer located in the headlamps of a vehicle. This bolt supports the headlamp, and if the bolt is loosened by external vibration, the angle of the light will change and block the vision of pedestrians or other drivers. In order to study these situations, the coefficient of friction between aiming bolts and retainers needs to be measured. In addition, the coefficient of friction of materials used in the headlamp should be obtained. To determine these two factors, a new device is designed for two cases: surface-surface contact and surface-line contact. To increase reliability of the results, the device is designed using an air-bearing stage which uses compressed air as lubricant to eliminate the friction of the stage itself. Experiments were carried out by applying various vertical forces, and the results show that the coefficient of friction can be measured consistently. The procedure for designing the device and the results are discussed.

• Earthquakes and Structures
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• v.17 no.3
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• pp.297-306
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• 2019

The extension of existing RC buildings is a challenging process, which requires efficient connection between existing and new materials to guarantee load transferring between the lap-spliced longitudinal columns' reinforcement. Therefore, the length of the columns' starter bars is a crucial factor, which decisively affects the seismic response of the new columns. In particular, when the length of the starter bars is short, then the length of the lap splices of reinforcement is inadequate to ensure load transfer between steel bars and concrete, with an indisputable detrimental impact on the seismic behaviour of the columns. Moreover, in most of the existing RC buildings the column starter bars are of particularly short length, while they have probably been bent, cut or corroded. In the present study, the effectiveness of both welded rebar and mechanical splices of reinforcement in ensuring load transferring between the starter bars and the longitudinal reinforcement of the new column was experimentally evaluated. Four cantilever column subassemblages were constructed and subjected to earthquake-type loading. Three of the specimens were used to examine different types of shielded metal arc welding (SMAW), while in the fourth subassemblage mechanical splices were tested. The hysteretic response of the columns was evaluated and compared to the behaviour of a fifth specimen with continuous reinforcement, tested by Kalogeropoulos and Tsonos (2019). Test results clearly demonstrated that the examined types of SMAW were equally satisfactory in ensuring the ductile seismic performance of the columns, while the mechanical splices found to be more susceptible to exhibit slipping of the bars.

• Journal of Trauma and Injury
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• v.34 no.1
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• pp.21-30
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• 2021

Purpose: The purpose of this study was to determine the influence of seasons and weather on the volume of trauma patients in central Korea. Methods: The records of 4,665 patients treated at Chungbuk National Hospital Regional Trauma Center from January 2016 to December 2019 were retrospectively reviewed. Meteorological data including hourly temperature (℃), precipitation (mm), humidity (%), and wind speed (m/s) for each district were collected retrospectively. Statistical analysis was done using the independent t-test, one-way analysis of variance (ANOVA), and linear regression analysis. Results: Patients' average age was 53.66 years, with a significant difference between men (49.92 years) and women (60.48 years) (p<0.001). Rolling/slipping down was a prominent cause of injury in winter (28.4%, n=283), with statistical significance (p<0.001). Trauma occurred least frequently in winter (p=0.005). Linear regression analysis revealed an increasing number of patients as the temperature increased (p<0.05), the humidity increased (p<0.001), and the wind speed decreased (p<0.001). Precipitation did not affect patient volume (p=0.562). One-way ANOVA revealed a decreased incidence of trauma when the temperature exceeded 30℃ (p<0.001), and when the humidity was more than 75%, compared to 25-50% and 50-75%. Conclusions: At the regional trauma center of Chungbuk National University Hospital, in central Korea, the number of trauma patients was lowest in winter, and patient volume was affected by temperature, humidity, and wind speed.

• Physical Therapy Rehabilitation Science
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• v.11 no.1
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• pp.66-77
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• 2022

Objective: This study is a systematic review conducted to analyze the environmental factors that cause falls in the older adult. Design: Systematic review Methods: The study was conducted by searching the Research Information Sharing Service (RISS), Korean studies Information Service System (KISS), and Data Base Periodical Information Academic (DBpia) databases for literature published in South Korea up to July 2020. A total of 12 studies were selected for analysis based on the inclusion and exclusion criteria. Results: The results of the analysis revealed that all the selected literature were surveys and the study subjects were 65 years of age and above. The sample size ranged from a minimum of 95 subjects to a maximum of 3,278. A total of eight tools were used to measure the environmental factors associated with falls. The prevalence and recurrence of falls increase with age and deterioration of health. Older adult individuals who experience falls encounter difficulties in recovering from impaired physical function and disability; moreover, in severe cases, falls may lead to death. Falls are largely associated with a combination of intrinsic and extrinsic (i.e., environmental) factors. The purpose of this study was to assess potential extrinsic risk factors for falls. Falls occur in indoor environments, such as washrooms, bathrooms and living rooms, and outdoor environments, including roads and stairways, depending on the season, time of day, and use of ambulatory aids. In such environments, falls are mainly caused by slipping and stuttering. Conclusions: Therefore, as the rate of fall is influenced by several factors, extrinsic factors should be improved by developing comprehensive accident prevention programs that address the improvement of environmental risk factors around places of residence to reduce risk factors among the older adult, who, especially, are at a high risk for falls.

• Archives of Craniofacial Surgery
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• v.23 no.5
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• pp.205-210
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• 2022

Background: Nasal bone fractures are the most common type of facial bone fracture, but are under-studied in adults above 65 years of age. Therefore, we investigated the epidemiology and patterns of nasal bone fractures among older adults in comparison to different age groups. Methods: This retrospective study included 2,321 nasal bone fracture patients who underwent surgery at our hospital from January 2010 to December 2017. The patients were classified by age as preschoolers, school-age children, young and middle-aged adults, and the elderly. We performed pairwise comparisons between elderly patients and each other age group in terms of sex, cause of injury, and fracture type. Results: The 2,321 nasal bone fracture patients included 76 elderly patients (50 men [65.8%] and 26 women [34.2%]). In these patients, the two most common injury causes were falling or slipping down (n= 39; 51.3%) and road traffic accidents (n= 19; 25.0%). According to the Stranc and Robertson classification, the most common force vector was lateral, and plane 2 fractures with lateral forces predominated. Conclusion: The elderly showed similar patterns of nasal bone fractures to those observed in young and middle-aged adults, but significant differences from preschoolers (in the injury vector and plane of fracture) and from school-age children (in the sex ratio and plane of fracture). However, elderly patients presented significantly different epidemiological characteristics compared to the other three groups. Therefore, it is necessary to improve the quality of life of the elderly and prepare for the upcoming super-aged society by taking steps to reduce the incidence and severity of fractures. Possible options for doing so include strengthening individual-level safety factors and expanding the social safety net for the elderly.

• Geomechanics and Engineering
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• v.31 no.6
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• pp.557-571
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• 2022

Landslides are often triggered by weak interlayers initiated in tailings dam foundations, and hazards gradually occur. This is serious for landslides in high tailings dams due to their high potential energy. Tailing samples with a fine-grained interlayer at a set dip angle were prepared. Consolidated undrained (CU) triaxial shear tests were carried out by using a high-pressure triaxial apparatus. The results were compared with the results under a low confining pressure. Four reasons were summarized for high tailings dams more prone to instability than low dams. The shear strength of the samples with dipping interlayers decreases with increasing dip angle. An obvious straight drop in the stress path after the peak occurs in samples with dipping interlayers at an angle of 60°. The effect of the interlayer on the mechanical behaviour of tailings is very sensitive, especially for the sample with a dipping interlayer at an angle of 60°. Shear slipping along the interlayer should be given more attention in tailings dams. Compared with the results under low confining pressure, the stress decreases continuously for the samples with dipping interlayers at large angles under high confining pressure. The positive pore pressure, which reduces the effective stress, occurred in tailings samples under high confining pressure. The residual strength of tailings under high confining pressure is smaller than that under low confining pressure. These factors increase the dam break risk and the disaster impact for high tailings dams.

• Journal of Trauma and Injury
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• v.36 no.4
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• pp.329-336
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• 2023

Purpose: In this study, we aimed to compare the characteristics of patients with trauma by age group in a single center in Korea to identify the clinical characteristics and analyze the risk factors affecting mortality. Methods: Patients aged ≥18 years who visited the Chungbuk National University Hospital Regional Trauma Center between January 2016 and December 2022 were included. The accident mechanism, severity of the injury, and outcomes were compared by classifying the patients into group A (18-64 years), group B (65-79 years), and group C (≥80 years). In addition, logistic regression analysis was performed to identify factors affecting death. Results: The most common injury mechanism was traffic accidents in group A (40.9%) and slipping in group B (37.0%) and group C (56.2%). Although group A had the highest intensive care unit admission rate (38.0%), group C had the highest mortality rate (9.5%). In the regression analysis, 3 to 8 points on the Glasgow Coma Scale had the highest odds ratio for mortality, and red blood cell transfusion within 24 hours, intensive care unit admission, age, and Injury Severity Score were the predictors of death. Conclusions: For patients with trauma, the mechanism, injured body region, and severity of injury differed among the age groups. The high mortality rate of elderly patients suggests the need for different treatment approaches for trauma patients according to age. Identifying factors affecting clinical patterns and mortality according to age groups can help improve the prognosis of trauma patients in the future.

• Archives of Craniofacial Surgery
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• v.24 no.6
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• pp.273-277
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• 2023

Background: The clinical characteristics of pediatric nasal fractures can vary depending on the child's age, social activities, and environment. Therefore, this study aimed to analyze these characteristics in different age groups. Methods: We retrospectively reviewed of a series of patients aged under 12 years who received treatment between 2013 and 2021. The initial study design involved dividing the patients into four age groups, corresponding to different developmental ages, but there were no cases in infants aged 0 to 1 year. Therefore, the patients were divided into three groups: group I, between 2 and 5; group II, between 6 and 9; and group III, between 10 and 12 years of age. The following parameters were evaluated: sex, age, etiology, fracture type and severity, and the incidence of septal injuries. Results: In total, 98 patients were included in this study. In group III, the ratio of boys to girls was 3.88:1, exceeding the overall ratio of 1.97:1. The most common cause varied with age: slipping down in group I, bumping accidents in group II, and sports accidents in group III. Concomitant septal injuries were present in 4.17% of patients in group I, 5.71% of patients in group II, and 28.21% of patients in group III. Conclusion: Increasing age was accompanied by a greater tendency for male predominance and a higher prevalence of sports-related causes and septal injuries. Violence was infrequent but started to become a contributing factor during school age. These varying environmental factors across age groups can offer valuable insights into the epidemiology and clinical characteristics of pediatric nasal bone fractures.