• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.47 no.3
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• pp.195-203
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• 2019

Since the hypersonic intake is directly related to the overall performance of the engine, it is essential to analyze performance characteristics under various off-design conditions. In this paper, Busemann intake and conical intake with external compression were designed, and numerical simulations were performed at on/off-design conditions. Based on the results, the overall performance characteristics of two types of intake were analyzed in various Mach numbers and angle of attacks. The results showed that performance degradation of Busemann intake with truncation angle of 2 degrees was minimal. Also, the performance of Busemann intake was higher than external compression intake at various Mach numbers, however, the starting characteristics were significantly reduced with an angle of attack.

• Physical Therapy Rehabilitation Science
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• v.7 no.4
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• pp.179-185
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• 2018

Objective: The purpose of this study was to analyze and compare vertical ground reaction forces during sit to stand (STS) and gait between female elderly and young individuals using the Wii Balance Board (WBB). Design: Cross-sectional study. Methods: Fifty-one female elderly people (age: $75.18{\pm}4.60years$), and 13 young people (age: $29.85{\pm}3.69years$) performed the five times STS test and gait respectively on the WBB. We analyzed time (s), vertical peak (%), integral summation (Int_SUM, %), and counter variables (%) in STS and 1st peak (body weight, BW%), 2nd peak (BW%), peak minimum (BW%), time (second), center of pressure (COP) path length (mm), and Int_SUM (BW%) in gait. The independent t-test was used to assess for differences in STS, gait ability, and general characteristics between the female elderly group and young adults group. With the first and last trials excluded, the mean value was obtained from the middle three of the five trials. Results: During STS, Int_SUM and time of young adults were significantly less than of the female elderly subjects. There were no significant differences in peak and counter variables. In gait, all variables (1st peak, 2nd peak, min, time, COP_path, and Int_SUM) showed significant differences between groups (p<0.05). This study demonstrated that the validity of vertical ground reaction forces occurring during STS and gait was significant in female elderly and young adults. Conclusions: Based on the measurement of vertical ground reaction forces in STS and gait using the WBB, it is possible to clinically improve the quality of geriatric physical therapy. Further studies are necessary to examine concurrent validity of elderly patients who have undergone total hip or knee replacement.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• v.22 no.3
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• pp.233-241
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• 2019

Purpose: Vitamin D deficiency is a condition widespread throughout the world. Recent studies have suggested that vitamin D deficiency was associated with obesity and metabolic syndrome. The purpose of the study was to examine the relationship between vitamin D deficiency and nonalcoholic fatty liver disease (NAFLD) in adolescents. Methods: The data were obtained from the Korean National Health and Nutrition Examination Survey from 2008-2014. A total of 3,878 adolescents were included in the study. Vitamin D deficiency was defined as a 25-hydroxyvitamin D concentration <20 ng/mL and suspected NAFLD was defined as an alanine transaminase concentration >30 U/L. Results: Vitamin D deficiency was noted in 78.9% of the studied population. Age, body mass index, waist circumference, and blood pressure, glucose, cholesterol, and triglyceride levels were significantly higher in adolescents with suspected NAFLD than in adolescents without suspected NAFLD, while the mean vitamin D level was significantly lower in adolescents with suspected NAFLD. The multivariate-adjusted odds of suspected NAFLD were higher with increased age, male gender, obesity, and metabolic syndrome. Individuals with vitamin D deficiency were at higher risk of suspected NAFLD (odds ratio, 1.77; 95% confidence interval, 1.07-2.95) after adjusting for age, gender, obesity, and metabolic syndrome. Conclusion: Vitamin D deficiency was associated with suspected NAFLD, independent of obesity and metabolic syndrome, in adolescents.

• Journal of The Korean Society of Emergency Medicine
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• v.29 no.6
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• pp.578-584
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• 2018

Objective: This study examined the initial partial pressure of carbon dioxide ($PCO_2$) as a possible indicator of prehospital ventilation and its association with prehospital i-gel in out-of-hospital cardiac arrest (OHCA) patients. Methods: The demographics and arrest parameters, including i-gel insertion and initial arterial blood gas analysis, of OHCA patients who visited the emergency department were analyzed retrospectively. Linear regression analysis was performed to examine the association between i-gel insertion and the initial $PCO_2$. Results: A total of 106 patients were investigated. Fifty-six patients had prehospital i-gel insertion and 50 patients did not have a prehospital advanced airway. The initial $PCO_2$ was higher in the i-gel group than the no advanced airway group (105.2 mmHg [77.5-134.9] vs. 87.5 mmHg [56.8-115.3], P=0.03). Prehospital i-gel insertion was associated with a higher initial $PCO_2$ level (${\beta}$ coefficient, 20.3; 95% confidence interval, 2.6-37.9; P=0.03). Conclusion: Prehospital insertion of i-gel was associated with higher initial $PCO_2$ values in OHCA patients compared to no advanced airway.

• Journal of Gynecologic Oncology
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• v.29 no.6
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• pp.92.1-92.9
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• 2018

Objective: To evaluate the effectiveness of the pulmonary recruitment maneuver (PRM) at the end of the operation to decrease laparoscopy-induced abdominal or shoulder pain after gynecological oncologic surgery. Methods: In total, 113 women undergoing laparoscopic surgery for malignant or premalignant gynecological lesions were assigned randomly to two groups: the PRM group (the patient was placed in the Trendelenburg position ($30^{\circ}$) and the PRM, consisting of two manual pulmonary inflations to a maximum pressure of $40cmH_2O$) (n=54) and the control group (n=52). Postoperative shoulder and abdominal pain was assessed 12, 24, and 48 hours later using a visual analog scale (0-10). In addition, the incidence of post-discharge nausea and vomiting was recorded until 48 hours after discharge. Results: Postoperative shoulder pain at 12 and 24 hours was significantly less severe in the PRM group ($2.2{\pm}0.5$ and $2.0{\pm}0.4$) than in the control group ($4.0{\pm}0.5$ and $3.9{\pm}0.4$; both p<0.001). The PRM significantly reduced the severity of upper abdominal pain at 12 and 24 h compared with the control group ($3.1{\pm}0.4$ and $2.9{\pm}0.4$ vs. $2.9{\pm}0.5$ and $4.9{\pm}0.5$; both p<0.001). The analgesic requirement during the postoperative period was similar in the two groups (control group, 78.8%; PRM group, 75.9%; p=0.719). Conclusion: The PRM effectively and safely reduced postoperative shoulder and upper abdominal pain levels in patients undergoing laparoscopic gynecological oncologic surgery. Trial registry at ClinicalTrials.gov, NCT01940042.

• Journal of the Korean Society of Propulsion Engineers
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• v.25 no.3
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• pp.42-55
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• 2021

In this study, the effect of nozzle performance according to the selection of the center line equation. Three of S-type nozzles and three of double S-type nozzles were designed using the curve equation and design parameters, and the nozzle shielding performance was evaluated using the shielding ratio definition. In order to analyze the internal flow of the nozzle, the characteristics of the velocity distribution and pressure distribution were studied, and the nozzle performance was evaluated through the total thrust ratio(f) and the nozzle insulation efficiency coefficient(η). On the other hand, the centerline with a sharply change in curvature at the entrance has a low nozzle performance and a high shielding rate. The double S-type nozzle is excellent nozzle performance and shielding rate by using a smooth centerline at the first curvature.

• Journal of Platform Technology
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• v.9 no.1
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• pp.40-45
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• 2021

Our daily lives have changed a lot because of the COVID-19 pandemic. This is essential to reduce the spread of COVID-19 due to public health measures such as social distancing. At the same time, however, they are exposed to depression, anxiety disorders, depressive disorders, trauma and stress-related disorders. For this, we developed an application that can check HRV data and stress index by measuring ECG and PPG based on a Smart Watch device that can measure bio-signals in real time. In the case of the developed application, the heart rate is measured and displayed in real time to deliver basic exercise information by measuring exercise, steps and calories, and total distance, and smoothly based on blood pressure, heart rate, and HRV data as a measurement program. Through this, I believe that the IoT Smart Stress Care Application, which can manage mental health by itself, will be helpful to patients with stress and depressive trauma disorders.

• Animal Bioscience
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• v.34 no.12
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• pp.1895-1902
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• 2021

Objective: Runs of homozygosity (ROH) are contiguous lengths of homozygous genotypes that can reveal inbreeding levels, selection pressure, and mating schemes. In this study, ROHs were evaluated in Wannan Black pigs to assess the inbreeding levels and the genome regions with high ROH frequency. Methods: In a previous study, we obtained 501.52 GB of raw data from resequencing (10×) of the genome and identified 21,316,754 single-nucleotide variants in 20 Wannan Black pig samples. We investigated the number, length, and frequency of ROH using resequencing data to characterize the homozygosity in Wannan Black pigs and identified genomic regions with high ROH frequencies. Results: In this work, 1,813 ROHs (837 ROHs in 100 to 500 kb, 449 ROHs in 500 to 1,000 kb, 527 ROHs in >1,000 kb) were identified in all samples, and the average genomic inbreeding coefficient (F_ROH) in Wannan Black pigs was 0.5234. Sixty-one regions on chromosomes 2, 3, 7, 8, 13, 15, and 16 harbored ROH islands. In total, 105 genes were identified in 42 ROH islands, among which some genes were related to production traits. Conclusion: This is the first study to identify ROH across the genome of Wannan Black pigs, the Chinese native breed of the Anhui province. Overall, Wannan Black pigs have high levels of inbreeding due to the influence of ancient and recent inbreeding due to the genome. These findings are a reliable resource for future studies and contribute to save and use the germplasm resources of Wannan Black pigs.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.30 no.4
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• pp.405-411
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• 2020

Objectives: The objectives of this study were to investigate whether airborne fibers were released to the outside air from the asbestos removal area in buildings, and to confirm the existence of asbestos fibers in samples using transmission electron microscopy(TEM). Methods: A total of 1,295 samples was collected from inside and outside 155 asbestos removal areas. To investigate the release of asbestos fibers from the removal area, samples were collected at three locations, such as an entrance to change room, an exit of negative pressure unit(NPU) and perimeter areas. Samples were also collected in the removal area prior to and after removal activity. All samples were analyzed by phase contrast microscopy(PCM) and one-tenth of the samples was analyzed using TEM to discriminate asbestos fibers. Results: During the asbestos removal activity, 27(4.1%) of 662 samples collected outside the removal area showed airborne fiber concentrations equal to or in excess of 0.01 f/cc, the permissible emission standard of the Korean Ministry of Environment. Further, 111 samples were analyzed using TEM. The distribution of asbestos fiber concentrations was log-normal. It was found that 51 of 111 samples(46%) contained asbestos fibers. Conclusions: There is a potential risk of asbestos exposure among neighbors and the public outside the asbestos removal areas. It is recommended that the asbestos removal work be conducted strictly following the specifications required by government and/or professional organizations.

• Bulletin of the Korean Chemical Society
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• v.15 no.3
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• pp.256-260
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• 1994

Perovskite type oxides of the $Sr_xHo_{1-x}FeO_{3-y}$ system with compositions of x=0.00, 0.25, 0.50, 0.75, and 1.00 have been prepared at 1200$^{\circ}$C in air. X-ray powder diffraction assigns the compositions with x=0.00 and 0.25 to the orthorhombic crystal system and those with x=0.50, 0.75, and 1.00 to the cubic one. The unit cell volumes of solid solutions increase with x in the system. Nonstoichiometric chemical formulas were determined by Mohr salt titration. The mole ratio of $Fe^{4+}$ ions to total iron ions and the concentration of oxygen ion vacancies increase with x. Mossbauer spectra for the compositions of x= 0.00, 0.25, and 0.50 show six lines indicating the presence of $Fe^{3+}$ ions in the octahedral site. However, the presence of $Fe^{4+}$ ions may also be detected in the spectra for the compositions with x=0.25 and x=0.50. In the compositions with x=0.75 and 1.00, single line patterns show also the mixed valence state of $Fe^{3+}$ and $Fe^{4+}$ ions. The electrical conductivity in the temperature range of -100$^{\circ}$C to 100$^{\circ}$C under atmospheric air pressure increases sharply with x but the activation energy decreases with the mole ratio of $Fe^{4+}$ ion. The conduction mechanism of the perovskite system seems to be hopping of the conduction electrons between the mixed valence iron ions.