• Korean Journal of Applied Biomechanics
• /
• v.15 no.3
• /
• pp.51-59
• /
• 2005

To examine the influence of aging on the mechanism of muscle fatigue, we compared the magnitude of central and peripheral fatigue in young and old women before, during and after a sustained submaximaI isometric contraction of elbow flexor muscles. Twelve women (6 young. $20.7{\pm}1.2$ years and 6 old, $68.8{\pm}29$ years) performed a contraction at 20% of maximal voluntary contraction (MVC) torque with their non-dominant arm. The old women were weaker than the young women, however their endurance time for the 20% contraction was longer compared with the young women ($1822{\pm}444$ vs. $1061{\pm}678$ sec, P <. 05). Both groups had a similar reduction in voluntary activation ratio (VA) during and after the fatiguing contraction. However, the old women showed much greater variability in VA before and after the contraction ($91.61{\pm}4.54%$ and $76.70{\pm}19.55\;%$ range of $79{\sim}99$ to $87{\sim}99%$ respectively) compared with the young women ($95.71{\pm}1.86\;%$ and $83.46{\pm}7.57\;%$ range of $39{\sim}75$ to $69{\sim}90%$, respectively). Furthermore, the EMG activity of the elbow flexor muscles and triceps brachii was greater for the old women compared with the young women throughout the fatiguing contraction, indicating different activation strategies with age. Indices of peripheral fatigue including twitch properties, showed that fatigue within the muscle was more rapid for the young women compared with the old women. These results suggest that although old women are weaker than young women, they have greater endurance due to mechanisms within muscle. Furthermore, old women showed great variability in their ability to optimally activate all muscle fiber compared with young women for an isometric contraction.

• The Journal of Churna Manual Medicine for Spine and Nerves
• /
• v.15 no.2
• /
• pp.33-41
• /
• 2020

Objectives The purpose of this report was to study the circulation of meridian WiGi, YoungGi, from the viewpoint of manual medicine. Methods First, the Korean Medical approach analyzes documents about the circulation of meridian WiGi, YoungGi, and the biomechanical approach is to analyze documents about kinetic force and kinematic movement. The third inherent energy approach is to analyze documents about craniosacral rhythm and visceral motility. Finally, it is to study the correlation between the circulation of meridian WiGi, YoungGi, and the viewpoint of biomechanics force and movement, the inherent energy of manual medicine. Results Meridian WiGi is fast, powerful, and changeful. It circulates through the head and extremities in the daytime and visceral organs at night. The deviation pelvis and distorted thoracic cage create kinetic force and kinematic movement. Meridian YoungGi is very small and soft energy and circulates meridians and visceral organs permanently. Craniosacral rhythm and visceral motility radiate continuously from cranial and visceral organs to the whole body. Conclusions Circulation of meridian WiGi is closely related to the biomechanical approach. In addition, circulation of meridian YoungGi is closely related to the inherent energy approach.

• Korean Journal of Organic Agriculture
• /
• v.9 no.3
• /
• pp.103-117
• /
• 2001

This study was inducted to investigate the effects of microbial fertilizers on the fields of young radish(Raphanus sativus L.), chemical components of plant and soil, and the microbial floras. Six microbial fertilizers, MPK+Husk+Palma, Husk+Palma, MPK+Compost, Compost, BIO Livestock Clean System(BLCS) cattle dropping, and Tomi were used. The yields of young radish were increased in six microbial fertilizer treatments. The fresh matter weight, the number of leaves, and the dry matter weight of young radish in BLCS cattle dropping treatment, the leaf length in MPK+Husk+Palma treatment, the sugar content in Husk+Palma treatment, arid the leaf width in Tomi treatment showed the highest amount, respectively. The effects of microbial fertilizers on chemical characteristics of young radish and soil were examined. Phosphoric acid amount of young radish in Tomi treatment was much higher than other treatments. Potassium amount of young radish showed high significance in all microbial fertilizer treatments compared with control, and shoved the highest in Compost treatment . Two components, phosphoric acid find potassium, in soil inoculated by microbial fertilizers showed significant. Phosphoric acid in the Tomi treatment and Potassium in Husk+Palma treatment were increased. The microorganic populations in soil inoculated with microbial fertilizers were examined. While the number of Bacillus in ceil was increased in MPK+Husk+Palma treatment, the numbers of total bacteria, actinomycetes, and fungi were increased in Tomi treatment.

• Toxicological Research
• /
• v.33 no.2
• /
• pp.157-164
• /
• 2017

This study was to evaluate the age-dependent effects of caffeine exposure on the long bones and reproductive organs using male rats. A total of 15 immature male rats and 15 young adult male rats were allocated randomly to three groups: a control group and two groups fed caffeine with 120 and 180 mg/kg/day for 4 weeks. Exposure to caffeine at either dose significantly reduced body weight gain; a proportional reduction in muscle and fat mass in immature animals, whereas a selective reduction in fat mass with relatively preserved muscle mass in young adult animals. The long bones of immature rats exposed to caffeine were significantly shorter and lighter than those of control animals along with decreased bone minerals. However, there was no difference in the length or weight of the long bones in young adult rats exposed to caffeine. Exposure to caffeine reduced the size and absolute weight of the testes significantly in immature animals in comparison to control animals, but not in young adult animals exposed to caffeine. In contrast, the adrenal glands were significantly heavier in caffeine-fed young adult rats in comparison to control animals, but not in caffeine-fed immature rats. Our results clearly show that the negative effects of caffeine on the long bones and testes in rats are different according to the age of the rat at the time of exposure, and might therefore be caused by changes to organ sensitivity and metabolic rate at different developmental stages. Although the long bones and testes are more susceptible to caffeine during puberty, caffeine has negative effects on body fat, bone minerals and the adrenal glands when exposure occurs during young adulthood. There is a need, therefore, to educate the public the potential dangers of caffeine consumption during puberty and young adulthood.

• Smart Structures and Systems
• /
• v.20 no.4
• /
• pp.473-481
• /
• 2017

This study suggests a simple, convenient and non-destructive method for investigation of the Young's modulus detection in stepped shafts which only utilizes the first-order resonant frequency in flexural mode and dimensions of structures. The method is based on the impulse excitation technique (IET) to pick up the fundamental resonant frequencies. The standard Young's modulus detection formulas for rectangular and circular cross-sections are well investigated in literatures. However, the Young's modulus of stepped shafts can not be directly detected using the formula for a beam with rectangular or circular cross-section. A response surface method (RSM) is introduced to design numerical simulation experiments to build up experimental formula to detect Young's modulus of stepped shafts. The numerical simulation performed by finite element method (FEM) to obtain enough simulation data for RSM analysis. After analysis and calculation, the relationship of flexural resonant frequencies, dimensions of stepped shafts and Young's modulus is obtained. Numerical simulations and experimental investigations show that the IET method can be used to investigate Young's modulus in stepped shafts, and the FEM simulation and RSM based IET formula proposed in this paper is applicable to calculate the Young's modulus in stepped shaft. The method can be further developed to detect mechanical parameters of more complicated structures using the combination of FEM simulation and RSM.

• Korean Journal of Childcare and Education
• /
• v.12 no.5
• /
• pp.17-45
• /
• 2016

This study aimed to investigate the effect of a young children's happiness program in relation with the Nuri curriculum on young children's happiness and self-esteem. Study subjects included 37 children aged 5 (experimental group 20, comparative group 17) enrolled in A day care center and D day care center located in K district, Seoul. As for the research procedure, an experiment was conducted 48 times in 18 weeks, and the experimental group carried out the children's happiness program linked with the Nuri curriculum. In contrast, the comparative group conducted general activities focusing on the subjects according to the Nuri curriculum. Study results show that there was a significant difference amongst 9 sub-domains related to young children's happiness (health, emotion, immersion, recognition and achievement, parent-child relationship, teacher-child relationship, peer relationship, spirituality, life satisfaction) and 3 sub-domains related to self-esteem (start and spirit of independence, sociality emotionality, academic achievement). Results of this study prove that the children's happiness program in relation with the Nuri curriculum is effective for increasing young children's happiness and self-esteem, and could be used as preliminary data for the possibility of a happiness program in early childhood education settings and happiness education in the future.

• Fashion & Textile Research Journal
• /
• v.22 no.2
• /
• pp.202-208
• /
• 2020

This study is to help produce highly comfortable and wearable and footwear based on the establishment of basic data for manufacturing elderly footwear patterns and products. For this, a survey of 207 women in their 20s and 60-70s was conducted to identify the wearing of shoes, inconvenience areas, purchase practices and footwear preferences by age group. The results are as follows. First, the average age of the young female group was 22.5 years old, the elderly female group was 68.8 years old, and the average shoe size was 236.3 mm for the young female group and 238.3 mm for the elderly female group. Second, young women wore shoes for a longer time than elderly women, resulting in swollen and numb legs, hardened soles, uncomfortable toes and sore heels. However, elderly women felt more uncomfortable wearing footwear than young women. They suffered pain in the joint area, heal and toe areas as well as had more toe deformations due to aging. Third, all age groups preferred athletic shoes and loafers as well as purchases from footwear brand stores and department stores. The elderly spent more money on shoes, longer time to buy and valued the feeling of wearing, whereas the young considered design first. Fourth, both age groups prefer low-heels and natural leather, the young preferred to wear various types of shoes; however, the elderly are found to desire shoes that are comfortable and stable in both form and wearing.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
• /
• v.8 no.1
• /
• pp.149-160
• /
• 2013

This aims to study impact of the youth start-up business incubating system by government's or local autonomous governments' center on start-up business performance. This focus on Youth Start-Up Business Support Program operated by Seoul Metropolitan City and explore practical alternatives. In this study, young entrepreneurs are defined as those who are aged between 20 and 40, and start-up is defined as an act by such entrepreneur that establishes an organization or system that produces any goods or services selected as business idea by utilizing capital in order to create profits. The empirical results are as follow; a significant correlation between scale of capital in initial stage by young entrepreneur graduating from Start-Up Business Support Center and start-up success satisfaction by young entrepreneurs. There is a significant correlation between the number of obtained intellectual properties before moving into Start-Up Business Support Center and start-up success satisfaction by young entrepreneurs. There is a significant correlation between the degree of satisfaction on start-up activity support fund for young entrepreneur in Start-Up Business Support Center and start-up success satisfaction by young entrepreneurs. There is a significant correlation between the degree of satisfaction on promotion and territorial cultivation support activities for young entrepreneur in Start-Up Business Support Center and start-up success satisfaction by young entrepreneurs. There is a significant correlation between the degree of satisfaction on collaboration support among member firms for young entrepreneur in Start-Up Business Support Center and start-up success satisfaction by young entrepreneurs. There is a significant correlation between the degree of overall satisfaction on start-up business support program for young entrepreneur in Start-Up Business Support Center and start-up success satisfaction by young entrepreneurs. The study has an implication that it provides a basic data on policy support strategies by central and local autonomous governments that facilitate young entrepreneurs to achieve start-up business goals by understanding the factors that affect the business performance of young entrepreneurs. In addition, the study offers an effective direction for young entrepreneurs in a way that promotes the start-up performance by young entrepreneurs, which expects to contribute to core factors of new employment opportunity creation as well as national and local economies, so that the author expects the study to play a role of raising the necessity of start-up business support for young entrepreneurs.

• Proceeding of EDISON Challenge
• /
• 2016.03a
• /
• pp.477-480
• /
• 2016

Based on the Jansen mechanism theory, a walking robot is developed, which is able to overcome the given obstacles. Taking joint positions and leg directions as design parameters, the walking robot is analyzed. In order to analyze and optimize the leg motion, Edison program and Jansen mechanism optimization solver are used, respectively. It is found that Edison program is so effective to determine joint variables and position of leg direction. With the help of these programs, lots of trials or errors could be saved.

• Journal of Nutrition and Health
• /
• v.31 no.9
• /
• pp.1404-1410
• /
• 1998

The purpose of this study was to investigate the effects of calcium intake levels on magnesium utilization in young and adult rats fed various levels of calcium(50, 100 or 200% of requirement) for 3 weeks. Feed intake, body weight gain, and feed efficiency ratios of the young group were significantly higher than those of the adult group. In calcium levels of tissues, serum calcium levels in young group were higher than in the adult group and kidney calcium levels in HCa(high-calcium group) were higher than in other groups. There was no significant difference in magnesium intake among age and diet groups. However, magnesium excretions through feces and urine in the adult group were higher than in the young group. Therefore, magnesium retention in the young group was higher than in the adult group. Especially in the young group, fecal magnesium excretion was increased with increasing levels of dietary calcium. Serum magnesium levels were lowest in YHCa(young 8t high-calcium) group, and there was no significant difference in liver and kidney levels among the calcium-diet groups. These results indicate that high calcium consumption promotes of fecal magnesium excretion and decreased magnesium retention rates in growing rats. Therefore, it is suggested that mineral interactions should be considered in the supplementation of dietary calcium intake for growth. (Korean J Nutrition 31(9) 1404-1410, 1998)