• Journal of the Korean Society of Physical Medicine
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• v.5 no.2
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• pp.273-280
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• 2010

Purpose : The purpose of this experiment was to evaluate the pre-application effect of low frequency electrical stimulation(LFES) on VEGF expression of atrophic muscle and to determine the optimal pre-application period of LFES for prevent muscle atropy Methods : Twenty-five adult sprague-dawley rats were randomly assigned to weight bearing group, hindlimb suspension for 14 days group, hindlimb suspension with pre-application of LFES for 14 days group, hindlimb suspension with pre-application of LFES for 11 dsys group and, hindlimb suspension with pre-application LFES for 7 dsys group. 16Hz of Biphasic pulse current was applied to gastrocnemius for 15min per days. Results : VEGF were decreased expression in HSG groups, whereas VEGF were significantly increased in HS+ES14G, HS+ES11G, HS+ES7G groups Conclusion : LFES during the hindlimb suspension showed a positive effect in VEGF induction and early application is strongly encourage VEGF induction. This indicated that pre-application of LFES could prevent muscle atrophy.

• Food Science of Animal Resources
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• v.39 no.3
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• pp.474-493
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• 2019

The aim of the study was to evaluate the effect of an early post-mortem low voltage electrical stimulation (ES) to localized part of carcasses [m. longissimus lumborum (LL) and m. biceps femoris (BF)] and determined the tenderness and flavor compounds of Hanwoo steers (n=16). Carcasses were stimulated within 30 min post-mortem for 60s using 60 volts and muscles aged 2 and 14 d. Degradation of Troponin-T were accelerated by ES and degraded little faster in BF muscle than LL. Level of free amino acid content of stimulated and aged muscles was significantly (p<0.05) greater than control for both muscles. Totally 63 volatile compounds were identified by using SPME-GC. The ES treatment significantly (p<0.05) affected the level of 20 volatile compounds of LL as well 15 volatiles in BF muscle along with total amounts of ketones, sulfur containing, pyrazines and furans. Low voltage ES could be applied to reduce the aging time and improve volatile flavor development by increasing important desirable volatile compounds such as 2-methylpyrazine, 2,5-dimethylpyrazines and 2-acetylthiazole etc. due to released free amino acids from protein degradation.

• Journal of the Korean Home Economics Association
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• v.47 no.2
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• pp.27-37
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• 2009

This study investigated the leadership skills of directors in addition to empowerment and Job satisfaction of teachers in Child Care Centers. The participants were 446 teachers who worked in early childhood educational institutes across Jeju province. The results were as following.: Firstly, transformational leadership significantly affected empowerment. However, individual consideration and transactional leadership from transformational leadership did not significantly affect empowerment. Secondly, individual consideration and intellectual stimulation from transformational leadership had a significant effect on job satisfaction. Also, reward for performance and exceptional management from transactional leadership had a significant effect on the job itself, the relationship, the working environment, and salary package among sub-variables in job satisfaction.

• Microbiology and Biotechnology Letters
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• v.22 no.4
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• pp.347-352
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• 1994

Cytotoxic test was performed by SRB assay on human epidermoid carcinoma HEp-2 cell line for screening the soil microorganism, secreting anticancer agent. One microorganism was selected among two thousand microorganisms for its highest cytotoxicity. And this microorganism was identified with Streptomyces species after performing of diaminopimeric acid and reducing sugar analysis of cell wall and analysing the cultural characteristics and named Streptomyces sp. SM 1119. The effect of anticancer agent in SM 1119 culture extract on the cell cycle was studied by using GG$_{o}$ synchronized NIH 3T3 cells. The extract inhibited the serum stimulation of GG$_{o}$ NIH 3T3 cell only within 1 hour after serum stimulation but not after 6 hours. The extract also reduced the amount of c-myc mRNA in Colo 320 cell. These results suggest that the anticancer agent in the extract inhibits the progression of cell cycle very early stages, probably from G$_{0}$ to G$_{1}$.

• The Korean Journal of Community Living Science
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• v.28 no.1
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• pp.115-130
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• 2017

This study was conducted to examine the relationship between pre-service early childhood teacher's motivations of choosing a teaching profession, educational belief, and self-directed learning readiness. The sample included 308 early childhood education major students, and the data were collected using the Modified Orientation to Teach Survey (MOTS), Teaching-belief type scale, and self-directed learning readiness scale. A statistical analysis included correlation analysis and stepwise multiple regression analysis. The results were as follows: 1) analysis of the relationship between pre-service early childhood teacher's motivations of choosing a teaching profession, educational belief, and self-directed learning readiness conveys that intellectual stimulation and self-directed learning had the strongest relationships while nature of work had the weakest. For educational belief and self-directed learning readiness, maturationism and interactionism showed significantly positive correlations while behaviorism displayed a negative correlation. Behaviorism had a significantly negative correlation with openness for challenge, a sub-factor of self-directed learning. 2) Analysis of the effect of pre-service early childhood teacher's motivations of choosing a teaching profession and educational belief on self-directed learning readiness indicates that pre-service early childhood teacher's motivations of choosing a teaching profession had a stronger effect on self-directed learning. These results suggest the following: successful performance as an early childhood teacher not only requires receiving institutionalized education but also self-directed learning while working as an early childhood teacher.

• Journal of Biomedical Engineering Research
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• v.35 no.6
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• pp.234-241
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• 2014

This study was designed to investigate the effects of stimulation intensity and inter-electrode distance on the parameters of the measured sensory nerve signal. 30 healthy subjects participated in this study. Sensory nerve signals were elicited by four different pulse amplitudes, i.e., 3, 6, 9, 12 mA, with the pulse width fixed at $500{\mu}s$. The sensory nerve signals elicited by the four different pulse amplitudes were measured by four different inter-electrode distances (20, 30, 40, and 50 mm). We extracted four parameters (pulse amplitude, pulse width, pulse area, and latency time from stimulation) from the sensory nerve signals. The measured pulse amplitude and pulse width were increased when the measuring inter-electrode distance was increased while the stimulating pulse amplitude was fixed. The measured pulse amplitude was saturated with the stimulating pulse amplitudes of over 6 mA while measuring inter-electrode distance. Under the same condition, measured pulse width was increased, and sensory nerve signal was initiated early. Sensory nerve signals, specially those of pulse amplitude, were distorted by a differential amplification method that commonly measures the human body signal. The experimental results indicate that the differential amplification method is required to be replaced when measuring nerve signals. Our observations suggested that the hyperpolarization of the action potential of the sensory nerve signal for preventing distortion could be used to clarify the correlation between the parameters of the sensory nerve signals and quantification of sensations.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.33 no.7
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• pp.629-636
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• 2009

Mechanical stimulation is known to play a vital role on the differentiation of mesenchymal stem cells (MSCs) to pre-osteoblasts. In this research, we developed a tensile cell stimulator, composed of a DC motor-driven actuator and LVDT sensor for measuring linear displacement, to study the effects of tensile stress on osteogenic differentiation of MSCs. First, we demonstrated the reliability of this device by showing the uniform strain field in the silicon substrate. Secondly, we investigated the effects of tensile stretching on osteogenic differentiation. We imposed a pre-set cyclic strain at a fixed frequency on cell monolayer cultured on a flexible silicon substrate while varying its amplitude and duration. 60 min of resting period was allowed between 30 min of cyclic stretching and this cycle is repeated up to 7 days. Under the combined stimulation with osteogenic media and mechanical stretching, the osteogenic markers such as alkaline phosphatase (ALP), osterix, and osteopontin began to get expressed as early as 4 days of stimulation, which is much shorter than what is typically required for osteogenic media induced differentiation. Moreover, different markers were induced at different magnitudes of the applied strains. Lastly, for the case of ALP, we observed the antagonistic effects of osteogenic media when combined with mechanical stretching.

• The Korean Journal of Food & Health Convergence
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• v.10 no.5
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• pp.1-13
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• 2024

This study evaluated the effectiveness of cognitive-based interventions for elderly individuals with Mild Cognitive Impairment (MCI) and early dementia over the past decade. A systematic review of 27 randomized controlled trials published from 2013 to 2023 focused on cognitive function, daily living activities, and quality of life improvements. The results showed that cognitive training and stimulation programs led to significant gains in memory, attention, and problem-solving skills. Additionally, improvements in daily functioning and overall quality of life were observed. Customized programs tailored to individual needs were found to be particularly effective, emphasizing the importance of personalized approaches. These findings suggest that cognitive interventions can help delay cognitive decline and maintain independence in older adults with MCI or early dementia. The review highlights the potential of such interventions in promoting healthy aging and improving the overall well-being of elderly individuals. Furthermore, these interventions can help older adults maintain meaningful social connections and enhance their emotional well-being in significant ways. Future research should aim to optimize and expand these programs for better outcomes and greater accessibility across various communities. This comprehensive review provides valuable insights for healthcare professionals and caregivers, demonstrating that cognitive-based interventions are a promising and effective approach for managing cognitive decline in older adults.

• The Korean Journal of Physiology
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• v.30 no.2
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• pp.197-208
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• 1996

Endosomes lower their internal pH by an ATP-driven proton pump, which is critical to dissociation of many receptor-ligand complexes, the first step in the intracellular sorting of internalized receptors and ligands. Endosomes are known to exhibit n great range of pH values that can vary between 5.0 and 7.0 within a single cell although the factors that regulate endosomal pH remain uncertain. To evaluate the morphological and topological differences of endosomes in the different stages, confocal microscopy was used. The early endosomes labeled with fluorescein isothiocyanate-dextran for 10 min at $37^{\circ}C$ were identifiable at the peripheral and tubule-vesicular endosome compartment. In contrast, the late endosomes formed by 10 min pulse and 20 min trace were located deeper in the cytoplasm and showed more vesicular features than early endosomes. For the purpose of determining whether ATP-dependent acidification was heterogeneous and whether the differences in acidification were attributed to differences in the activity of $Na^{+}-K^{+}$-ATPase and/or $Cl^{-}$ channel, endocytic compartments were fractionated into subpopulation using percoll gradient and measured ATP-dependent acidification. While all fractions exhibited ATP-dependent acidification activity, both the initial rate of acidification and extent of proton translocation were lower in early endosomes and gradually increased in late endosomes. Phosphorylation by PKA and ATP enhanced ATP-dependent acidification in both early and late endosomes, hut there was no difference in the degree of enhancement by phosphorylation between two subpopulations. When ATP-dependent acidification was determined in the presence or absence of vanadate ($Na_{3}VO_{4}$) or ouabain, only early endosomes exhibited the vanadate or ouabain dependent stimulation of acidification activity, suggesting the inhibition of $Na^{+}-K^{+}$-ATPase. Therefore, it seems probable that the inhibition of early endosome acidification by $Na^{+}-K^{+}$-ATPase observed in vitro at least in part plays a physiological role in controlling the acidification of early endosomes in vivo.

• Korean Journal of Microbiology
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• v.24 no.1
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• pp.32-37
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• 1986

In fermentation studies it revealed that Streptomyces sp. SMF 3001 started to synthesize extracellular alkaline protease from early exponential phase of cell growth. The biosynthesis of the alkaline protease was greatly induced by skim milk as a sola nitrogen source and further stimulation was observed under inorganic sulphur limited culture. However, it was found that the biosynthesis was apparently repressed by $NH_4^+$ and free amino acids, specially by cysteine. It was considered that the strain SMF 301 of Streptomyces sp. would produce the alkaline protease for the uptake of sulphur compounds from protein contained in the culture broth.