• The Korean Journal of Physiology and Pharmacology
• /
• 제22권4호
• /
• pp.427-436
• /
• 2018

The objective of this study was to analyze the concurrent treatment effects of ursolic acid (UA) and low-intensity treadmill exercise and to confirm the effectiveness of UA as an exercise mimetic to safely improve muscle atrophy-related diseases using Sprague-Dawley (SD) rats with skeletal muscle atrophy. Significant muscle atrophy was induced in male SD rats through hind limb immobilization using casting for 10 days. The muscle atrophy-induced SD rats were group into four: SED, sedentary; UA, daily intraperitoneal UA injection, 5 mg/kg; EX, low-intensity (10-12 m/min, $0^{\circ}$ grade) treadmill exercise; and UEX, daily intraperitoneal UA injection, 5 mg/kg, and low-intensity (10-12 m/min, $0^{\circ}$ grade) treadmill exercise. After 8 weeks of treatment, endurance capacity was analyzed using a treadmill, and tissues were extracted for analysis of visceral fat mass, body weight, muscle mass, expression of muscle atrophy- and hypertrophy-related genes, and endurance capacity. Although the effects of body weight gain control, muscle mass increase, and endurance capacity improvement were inadequate in the UA group, significant results were confirmed in the UEX group. The UEX group had significantly reduced body weight and visceral fat, significantly improved mass of tibialis anterior and gastrocnemius muscles, and significantly decreased atrophy-related gene expression of MuRF1 and atrogin-1, but did not have significant change in hypertrophy-related gene expression of Akt and mTOR. The endurance capacity was significantly improved in the EX and UEX groups. These data suggest that concurrent treatment with low-intensity exercise and UA is effective for atrophy-related physical dysfunctions.

• Transactions of the Korean hydrogen and new energy society
• /
• 제25권4호
• /
• pp.393-404
• /
• 2014

Unmanned aerial vehicles (UAVs) have been applied to not only military missions like surveillance and reconnaissance but also commercial missions like meteorological observation, aerial photograph, communication relay, internet network build and disaster observation. Fuel cells make UAVs eco-friendly by using hydrogen. Proton exchange membrane fuel cells (PEMFCs) show low operation temperature, high efficiency, low noise and high energy density and those characterisitcs are well fitted with UAVs. Thus Fuel cell based UAVs have been actively developed in the world. Recently, fuel cell UAVs have started to develope for high altitude UAVs because target altitude of UAVs is expanded upto stratosphere altitude. Long endurance of UAVs is essential to improve effects of the missions. Improvement of UAV endurance time could be fulfilled by developing a hydrogen fuel storage system with high energy density and reducing the weight of UAVs. In this paper, research trend and analysis of fuel cell UAVs are introduced in terms of their altitude and endurance time and then the prospect of fuel cell UAVs are shown.

• Journal of the Korean Applied Science and Technology
• /
• 제37권6호
• /
• pp.1669-1677
• /
• 2020

The purpose of this study was to evaluate the effects of a 14-week proprioceptive resistance exercise on muscle endurance strength, dynamic balance and gait ability of elderly women in a social welfare facility. Thirty community dwelling elderly subjects (mean age 70.84±3.33) divided into experimental (n=15) and control (n=15) groups. The participants performed the muscle endurance strength(30sec hair stand), dynamic balance (3m up and go) and low extremity performance (10m walking, 400m walking) pre and after the training program. The exercise groups were submitted to 14 weeks proprioceptive training with a Swiss ball three times a week. As a results were as follow. Significantly improvements were observed in low extremity strength and dynamic balance. And there have significantly improvements in 10m walking, 400m walking. Conclusionly, the improvement of dynamic balance and gait ability by proprioceptive resistance training will reduce the possibility in female elderly people.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• 제50권7호
• /
• pp.489-496
• /
• 2022

This paper introduces the system for KAU-SPUAV, which is designed and developed by Korea Aerospace University, and verifies its performance through flight test. Specification of two versions of KAU-SPUAV, avionics system, and Ground Control System (GCS) are introduced. Three missions are performed with suggested UAVs: LTE signal mapping, circumnavigation of Jeju island seashore, and long endurance flight. Each mission consists of long distance and long endurance flight which takes advantage of KAU-SPUAV. Research team of KAU-SPUAV confirmed its versatility through suggested flight data. Also based on flight results, the team found the potential of performance improvement of KAU-SPUAV.

• The Journal of Korean Medicine
• /
• 제34권1호
• /
• pp.29-34
• /
• 2013

Objectives: This report aimed to demonstrate effect of human placental extract (HPE) pharmacopuncture in students suffering fatigue due to hard work and mental stress. Methods: Thirty-four college students, preparing for the final-term exam, received pharmacopuncture of HPE into Kwanwon (CV4) subcutaneously twice a week for 7 weeks. After every pharmacopuncture of HPE, degree of fatigue was surveyed by questionnaire including physical condition, physical endurance, concentration and memory. Results: Pharmacopuncture of HPE into CV4 gently improved physical condition, physical endurance, concentration and memory. Improvement of physical condition was especially positively correlated with the increasing number of pharmacopuncture of HPE into CV4 as confirmed by calculation of Pearson coefficient. Conclusions: Pharmacopuncture of HPE into CV4 alleviated fatigue in the students from hard work and mental stress.

• Journal of the Korean Society for Precision Engineering
• /
• 제24권12호
• /
• pp.74-81
• /
• 2007

This paper focuses on improvement of the reliability for endurance test to serve military automobiles. The driving loads have been measured by use of the wireless telemetry system for the drive shaft of the 4-wheel drive car. In order to analyze the transmission input torque and engine revolution of loads of the test courses and unpaved road have been made use of the revolution counting and cumulative damage by miner's rule. This paper presents the evaluated result for quantified damage about the test courses and roads.

• Transactions of the Korean Society of Mechanical Engineers
• /
• 제19권2호
• /
• pp.402-407
• /
• 1995

The effects of room temperature and strain aging treatment are discussed on the critical condition for the onset of growth of non-propagating cracks on 0.15% C low carbon steel, with special emphasis on the length of the critical non-propagating crack and on the crack opening displacement(COD) at the crack tip. It is found from the experimental analysis that room temperature and strain aging of a fatigue pre-cracked specimen introduced the closure of a crack tip of the pre-crack and the reduction of crack opening displacement at the wake of crack, together with an improvement in crack growth resistance of the microstructure. This may cause an increase in the endurance limit of the specimen, through the enhancement of effective stress for the onset of growth of the critical non-propagating crack.

• Journal of the Korean Society for Aviation and Aeronautics
• /
• 제21권1호
• /
• pp.30-38
• /
• 2013

This paper describes the design optimization of Unmanned Aerial Vehicles(UAVs). An optimization framework has been developed and implemented for the conceptual design of UAVs. An integrated design analysis program was developed with several analysis modules such as propulsion, performance, mission, weight, and stability and control. A UAV configuration design optimization was performed by implementing the integrated analysis to enhance the endurance of UAVs. A SQP optimizer was utilized to build an optimization module for this program and sensitivity analysis was performed to determine the trends of shape variables for developing optimization objective. In conclusion, the results indicate that the resulting optimized UAVs configurations show performance improvements over the baseline design and reliable analysis results.

• Journal of the Korean Applied Science and Technology
• /
• 제37권3호
• /
• pp.571-581
• /
• 2020

The purpose of this study was to investigate the effect of endurance and resistance exercise by using different intensity on diabetic-related blood profiles in impaired glucose tolerance mice. 54 C57BL/6 mice were divided into (1) Control group (CO, n=9), (2) impaired glucose tolerance group (IGT, n=9), (3) IGT + 50% of VO_2max endurance exercise group (IGT50A, n=9), (4) IGT + 75% of VO_2max endurance exercise group (IGT75A, n=9), (5) IGT +50% of 1RM resistance exercise group (IGT50R, n=9), 그리고 (6) IGT + 75% of 1RM resistance exercise group (IGT75R, n=9). Endurance exercise program was performed 40 min/day, 5 days a week for 8 weeks on treadmill. Resistance exercise program was consisted in ladder-climbing 8 set/day, 5 days a week for 8 weeks. After completed the exercise program, there was no different insulin level in the groups. The fasting glucose was significantly lower in CO than in other groups, and it was not different among the exercised groups. However, IGT75R was statistically lower than IGT. HOMA-IR was only different between CO and IGT. HbA1c was higher in IGT than in other groups. As compared with exercised groups, IGT 75A was lower than IGT50R. TC was lower in CO than in other groups, but there was no different in TG. Endurance exercise groups showed higher than CO and IGT in HDL-C level. LDL-C was lower in CO than other groups. In addition, IGT75A was lower than IGT and IGT50R in LDL-C level. In conclusion, 75% of 1RM resistance exercise had more positive effect on fasting glucose, and 75% of VO_2max endurance exercise improved HbA1c and LDL-C level. In addition, endurance exercise had more effective in HDL-C improvement as compared with resistance exercise.

• PNF and Movement
• /
• 제14권2호
• /
• pp.67-74
• /
• 2016

Purpose: The purpose of this study was to prove the effects of coordinative locomotion training (CLT) on walking speed, walking endurance, and balance for incomplete spinal cord injury patients. Methods: Ten subjects were randomly assigned to the CLT group (n = 5) and the treadmill (TM) group (n = 5). The CLT group performed PNF pattern exercise using the motions of the sprinter and skater for 30 minutes, while the TM group performed using a treadmill for 30 minutes. Both groups performed these therapeutic interventions for five days per week, for a period of four weeks. A 10 meter walking test, Berg Balance Scale (BBS), and 6 meter walking test were used for the assessment of gait speed, balance, and gait endurance. The SPSS Ver. 18.0 statistical program was used for data processing. A Wilcoxon signed rank test was used for the comparison of pre- and post-intervention performance and a Mann-Whitney test was used for comparison between the groups. The significance level for the statistical inspection was set at 0.05. Results: Both groups showed significant improvements in the 10 meter walking test, Berg Balance Scale, and 6 meter walking test (P < 0.05). Conclusion: CLT had an effect on the improvement of walking speed, walking endurance, and the balance of incomplete spinal cord injury patients. Thus, we suggest that CLT is a therapeutic intervention for incomplete spinal cord injury patients.