• The Korean Journal of Physiology and Pharmacology
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• v.20 no.1
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• pp.111-117
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• 2016

Vagal nerve activity has been known to play a crucial role in the induction and maintenance of atrial fibrillation (AF). However, it is unclear how the distribution and concentration of local acetylcholine (ACh) promotes AF. In this study, we investigated the effect of the spatial distribution and concentration of ACh on fibrillation patterns in an in silico human atrial model. A human atrial action potential model with an ACh-dependent $K^+$ current ($I_{KAch}$) was used to examine the effect of vagal activation. A simulation of cardiac wave dynamics was performed in a realistic 3D model of the atrium. A model of the ganglionated plexus (GP) and nerve was developed based on the "octopus hypothesis". The pattern of cardiac wave dynamics was examined by applying vagal activation to the GP areas or randomly. AF inducibility in the octopus hypothesis-based GP and nerve model was tested. The effect of the ACh concentration level was also examined. In the single cell simulation, an increase in the ACh concentration shortened $APD_{90}$ and increased the maximal slope of the restitution curve. In the 3D simulation, a random distribution of vagal activation promoted wavebreaks while ACh secretion limited to the GP areas did not induce a noticeable change in wave dynamics. The octopus hypothesis-based model of the GP and nerve exhibited AF inducibility at higher ACh concentrations. In conclusion, a 3D in silico model of the GP and parasympathetic nerve based on the octopus model exhibited higher AF inducibility with higher ACh concentrations.

• Journal of Digital Convergence
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• v.15 no.2
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• pp.519-525
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• 2017

The purpose of this study is to elaborate the factors and strategies to revitalize the policies of elderly-friendly care industry. The analysis was carried out using the method called DEMATEL. The analytical method is based on the DEMATEL technique. The purpose of this study is to clarify the complexity and unclear relationship between activation factors and factors that constitute the elderly friendly-care industry through the prioritization of policy strengthening. As the result of analysis, it was analyzed that the most intensive activation intensity was the highest total strength of meal service(22.095). Followed by health promotion facilities(19.97) and health care(17.726). The lowest factor is sport(15.896). Therefore, in order to improve and promote these factors, continuous policy measures should be sought that are closely related to facility care services, home care services, and preventive support services.

• Physical Therapy Rehabilitation Science
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• v.7 no.4
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• pp.164-171
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• 2018

Objective: The purpose of this research was to determine the immediate effects of wearing a foot-pressure-based insole (FPBI) on ankle dorsiflexion range of motion (DFROM), postural sway, and muscle activation in healthy individuals with genu varum. Design: Cross-sectional study. Methods: This study was conducted on thirteen adults, with six male and seven females subjects. The mean age was 24.08 years. Foot pressure was measured to apply the FPBI and the weight bearing lunge test was performed with the application of a flat insole (FI) and FPBI. Examination was randomly performed in four conditions to measure both postural sway and muscle activation. All participants applied both the FI and FPBI with four conditions. The four conditions were as follows: 1) Romberg test posture with eyes closed, 2) Romberg test posture with eyes opened, 3) dominant single leg standing with eyes opened, and 4) non-dominant single leg standing with eyes opened. Results: For ankle DFROM between the FI and FPBI, a significant increase was observed in both the dominant and non-dominant leg (p<0.05). For postural sway between the FI and FPBI in the Romberg test posture with eyes closed and dominant single leg standing with eyes opened conditions, a significant decrease was observed (p<0.05). However, the postural sway between FI and FPBI in the Romberg test posture with eyes opened and non-dominant single leg standing with eyes opened, no significant decrease was observed. Also, there were no significant effects on muscle activation between the application of the FI and FPBI. Conclusions: The result showed that FPBI immediately improved ankle DFROM and postural sway. It seems that FPBI may improve genu varum in healthy individuals with genu varum.

• Archives of Orthopedic and Sports Physical Therapy
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• v.14 no.2
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• pp.55-64
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• 2018

Purpose : The purpose of this study was to investigate the effect of the sprinter and skater combined patterns on muscle contraction onset time and muscle activation of body stabilizing muscles. Method : Our study included young and healthy men in their 20s. The participants used the sprinter and skater combined patterns of the proprioceptive neuromuscular facilitation (PNF) methods to measure muscle activation and muscle contraction onset time of the trunk muscles. To measure muscle contraction onset time and muscle activation, electrodes were attached to the rectus abdominis (RA), external oblique (EO), internal oblique (IO), and erector spinalis (ES) regions. Significant differences were identified using a paired t-test and a one-way analysis of variance (ANOVA) analysis. Result : In the sprinter combined pattern, the muscle with the fastest onset time of contraction was the RES, and that with the slowest was the RRA (p<.001). In the skater combined pattern, the muscle with the fastest onset time of contraction was the LES, and that with the slowest was the LRA (p<.001). In the sprinter combined pattern, the REO and LIO presented medium muscle contraction onset times (p<.001). In the skater combined pattern, the LEO and RIO presented medium muscle contraction onset times (p<.001). Conclusions: Based on these results, these patterns could be used as exercise methods for the elderly with delayed proactive response speeds of the body stabilization methods due to imbalances in body stabilizing muscles or limbs movement.

• Journal of the Korean Society of Physical Medicine
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• v.14 no.2
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• pp.71-77
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• 2019

Purpose: The purpose of this study was to compare the level of muscle activation on the cervical erector spinae (CES), lumbar erector spinae (LES), and upper trapezius (UT) according to the sitting postures while using a smartphone in the bathroom. Method: Thirty-two healthy subjects were recruited for this study. The CES, LES, and UT were evaluated by surface electromyography according to two sitting postures while using a smartphone on the toilet seat. A paired t test was performed for the root mean square of reference voluntary contraction (%RVC) comparisons between two sitting postures, and one-way ANOVA was used to compare the three muscle activations within each posture. Results: A comparison between the two sitting postures revealed the muscle activation of both CESs in sitting posture 2 and both LESs in sitting posture 1 to be significantly higher than those of the others. In sitting posture 1, the muscle activation of both LESs was significantly higher than those of the CES and UT. In sitting posture 2, the muscle activation of both CESs was significantly higher than those of the LES and UT. Conclusion: High muscle activation of the CES and LES was observed according to the sitting postures when using smartphone in the restroom. Therefore, long time use of smartphones on a toilet seat should be avoided.

• PNF and Movement
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• v.21 no.1
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• pp.107-117
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• 2023

Purpose: The aim of this study is to compare the immediate effects of weight-assisting methods on vastus medialis oblique (VMO) and vastus lateralis (VL) muscle activation, on the VMO/VL muscle activation ratio, and on muscle onset time in healthy subjects when ascending stairs. Methods: Healthy participants were randomly assigned to the belt group (n = 11), hand group (n = 11), and control group (n = 11). In the belt group, a belt was wrapped around the sacrum and pulled forward with both hands, moving the center of weight forward, while ascending stairs. The hand group grasped the hips with both hands and climbed stairs, assisting their weight from the rear and moving the center of weight backward, and the control group climbed the stairs without any intervention. Results: Muscle activation of the VMO decreased significantly after the intervention in the belt and hand groups, and activation of the VL muscle in both groups showed a greater decrease than that of the VMO muscle. Further, the VMO/VL muscle activation ratio increased significantly, with an improvement shown in the order of the belt group, hand group, and control group, while muscle onset time also improved in the order of the belt group, hand group, and control group. Conclusion: The belt group demonstrated the greatest effect across all dependent variables, confirming that in clinical practice, these two weight-assisting methods are more effective interventions during stair ascent for patients with knee joint instability, pain, and imbalance than no assistance.

• Journal of the Korean Society of Physical Medicine
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• v.13 no.3
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• pp.11-17
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• 2018

PURPOSE: The purpose of this study was to identify the effect of abdominal stabilization exercise with Stabilizer and Gymball. METHODS: The participants were divided randomly into 2 groups each of 20 participants in the gymball exercise group and 20 participants in the exercise group. The changes of respiratory muscle activity between the two groups were measured three times a week for 4 weeks. The activity of rectus abdominis and internal oblique was measured using surface EMG to measure respiratory muscle activity. The training was repeated five sets, and one set was repeated 6 times with one 10 second exercise and 5 second rest. RESULTS: The results of the study showed that there was a significant difference in the amount of respiratory accessory muscle activation, inspiratory pressure, respiratory minute volume at the experimental group with stabilizer and control group with gymball exercise. Between-group difference was statistically significant only for rectus abdominis muscle activation. CONCLUSION: Both the stabilizer and the gymball exercises were effective in improving the respiratory rate but there was no difference between the two groups. Also, when comparing activity of muscle in both group, both groups were effective in improving and more effective than improvement of muscular activity of stabilizer in muscle of stabilizer.

• Journal of the Korean Institute of Gas
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• v.24 no.3
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• pp.40-46
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• 2020

Tertbutylperoxymaleate is the one of the organic peroxides used as a raw material of initiator formulations of artificial marble manufacturing. In this study, the thermal decomposition characteristic of TBPM was evaluated using the differential scanning calorimeter in the air and nitrogen circumstance. Regardless of the reaction atmosphere, TBPM showed the exothermic peak due to the drastic decomposition reaction below 130 ℃. The activation energy estimated by dynamic methods had a range of 203~217 kJ/mol and that estimated by model-free analysis method had a range of 118~232 kJ/mol with a thermal conversion. And the ADT₂₄, the temperature that lead to the maximum heating rate within 24 hours, was evaluated as (80~95) ℃ using the estimated activation energy.

• Asian Pacific Journal of Cancer Prevention
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• v.13 no.6
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• pp.2485-2489
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• 2012

Purpose: Notch is an important signaling pathway that regulates cell fate, stem cell maintenance and the initiation of differentiation in many tissues. It has been reported that activation of Notch-1 contributes to tumorigenesis. However, whether Notch signaling might have a role in chemoresistance of prostate cancer is unclear. This study aimed to investigate the effects of Notch-1 silencing on the sensitivity of prostate cancer cells to docetaxel treatment. Methods: siRNA against Notch-1 was transfected into PC-3 prostate cancer cells. Proliferation, apoptosis and cell cycle distribution were examined in the presence or absence of docetaxel by MTT and flow cytometry. Expression of $p21^{waf1/cip1}$ and Akt as well as activation of Akt in PC-3 cells were detected by Western blot and Real-time PCR. Results: Silencing of Notch-1 promoted docetaxel induced cell growth inhibition, apoptosis and cell cycle arrest in PC-3 cells. In addition, these effects were associated with increased $p21^{waf1/cip1}$ expression and decreased Akt expression and activation in PC-3 cells. Conclusion: Notch-1 promotes chemoresistance of prostate cancer and could be a potential therapeutic target.

• Journal of the Korean Society of Radiology
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• v.10 no.7
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• pp.489-494
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• 2016

Nuclear reaction which occurs in the cyclotron generate unnecessary neutrons. The results of this happening can radioactivate surrounding materials and radioactive materials cause radiation exposure. When people take radioactive air, it makes internal exposure. The purpose of this study was to analyze the radioactive air inside of the ultra-compact 16.5 MeV cyclotron in operation. As a result of study, the radio activation occurred by compact cyclotron generates a very low internal exposure to workers. Comparing the radioactivity from radioactive nuclide with legal standard, that was under reference value. However, it could be at risk for internal exposure in case of higher energy cyclotron. Therefore, legal standard is needed for ventilation equipment of radiation facilities.