• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.20 no.11
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• pp.733-738
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• 2008

Due to environmental concerns $CO_2$ has been reintroduced as a potential candidate to replace HFCs in refrigeration systems. Oils are always required in a vapor-compression cycle, and thus it is necessary to precisely estimate the thermodynamic mixture properties of $CO_2$-lubricant oil. In the present study, the density and the viscosity of the mixture was calculated by the Redlich and Kwong type EoS and the modified Peng and Robinson type viscosity EoS, respectively. The viscosity model was based on the similarity between P-v-T and T-$\mu$-P relationships. The predicted results were compared with the experimental data of Pens ado et al. whose test conditions were 100$\sim$650 bar of pressure and 303 K$\sim$353 K of temperature with the $CO_2$-POEs mixtures under 92.2 wt.% and 83.3 wt.% of $CO_2$ concentration. The mean deviations of the mixture density were 7.93% and 8.32% for 92.2 wt.% and 83.3 wt.% of $CO_2$ concentration, respectively. Concerning the viscosity, the mean deviations were 4% and 10% for 92.2 wt.% and 83.3 wt.% of $CO_2$ concentration under the Pensado et al.'s test conditions.

• Journal of the Korean Society of Physical Medicine
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• v.16 no.4
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• pp.95-102
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• 2021

PURPOSE: This study examined the muscle activity of the abdominal muscle when lifting with abdominal hollowing with visual feedback and lifting with a pelvic compression belt. This study suggests how to lift an object safely in the workplace for people who bend their backs repeatedly. METHODS: The study was conducted on healthy men in their 20s and 30s. When lifting a 7kg object, lifting with abdominal hollowing with visual feedback, and lifting an object with a pelvic compression belt were performed three times in random order. The muscle activities were measured rectus abdominis (RA), external oblique (EO), internal oblique/transverse abdominis (IO/TrA) muscles, and abdominal hollowing exercises, and box lifting exercises were carried out in advance before the experiment. One-way ANOVA was used to compare muscle activities, and a Tukey HSD was used for post-analysis. The level of significance was set to .05. RESULTS: According to the study, there was no significant difference in muscle activity of the RA muscle depending on the lifting method (p > .05). There were significant differences between the EO and IO/TrA muscle (p < .05). The IO/TrA muscle activity showed the largest increase in lifting an abdominal hollowing with visual feedback (p < .05). The EO muscle activity increased in pelvic compression belt lifting (p < .05). The muscle activity was increased in RA, but there was no significant difference (p < .05). CONCLUSION: Abdominal hollowing lifting with visual feedback increases the muscle activity of the IO/TrA muscle, which is higher than normal, and affects the core stability of the body.

• Physical Therapy Rehabilitation Science
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• v.13 no.1
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• pp.78-85
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• 2024

Objective: This Study aimed to examine the changes in muscle activity of trunk muscles by performing three squat exercises on normal adults. Design: cross-sectional study Methods: Thirty-two adult subjects participated in this study. General squat, overhead squat, and overhead squat combined with abdominal stabilization were randomly performed for 5 seconds, 3 times, to calculate the average muscle activation. Muscle activation was normalized using electrodes on the rectus abdominis, external oblique, internal oblique, and erector spinae muscles to measure maximum voluntary isometric contraction (MVIC) for 5 seconds, repeated 3 times each. Results: There was a significant difference in the mean and maximal muscle activity of the bilateral erector spinae (ES) when comparing the squat to the overhead squat (p<0.05). There was a significant difference (p<0.05) in the mean and maximal muscle activity of the bilateral external oblique (EO) when comparing the overhead squat to the overhead squat combined with the abdominal stabilization technique. When comparing the squat to the overhead squat with abdominal stabilization, there was a significant difference in the mean and maximum muscle activity of the bilateral RA, EO, and left Internal oblique (IO) (p<0.05), and there was a significant difference in the maximum muscle activity of the bilateral erector spinae (ES) (p<0.05). Post hoc tests showed significant differences between squatting methods for the RA, EO, IO, and ES (p<0.017). Conclusion: The results of this study showed that squats combined with abdominal stabilization were more effective at activating core muscles than squats or overhead squats alone.

• Journal of the Korean Society of Physical Medicine
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• v.6 no.3
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• pp.303-310
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• 2011

Purpose : This study examined the feedback effect of real-time ultrasound imaging on the thickness of transversus abdominis(TrA), internal abdominal oblique(IO) and external abdominal oblique(EO) during abdominal hollowing exercise(AHE) in crook lying. Methods : We performed this study on 30 healthy men who voluntarily consented to participate in this study after listening to its purpose and method. All subject were divided into an experimental group(n=15) with using the real-time ultrasound imaging feedback(RUIF) and a control group(n=15) without the RUIF The thickness changes between rest and AHE were compared between the two groups in crook lying. Results : The difference in TrA and EO thickness changes between the groups were significant in crook lying (p<0.05). Conclusion : The group with using real-time ultrasound imaging feedback showed a higher increase in the thickness of TrA than the other group without real-time ultrasound imaging feedback. And the thickness of EO in the group with using real-time ultrasound imaging feedback decreased than the other group without real-time ultrasound imaging feedback. If the muscle thickness can be regarded as an indicator of muscle activity, RUIF will be helpful for inducing the independent activity of TrA by reducing the activities of abdominal muscles such as EO.

• Journal of the Korean Society of Physical Medicine
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• v.10 no.3
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• pp.81-86
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• 2015

PURPOSE: Bridge exercises are broadly used to develop trunk co-activation patterns that promote spine stability. This study was to analyze the trunk muscle activity during bridge exercise with various shoulder support surface(stable, sling, Swiss ball). METHODS: The subjects were 20 healthy subjects in their twenties. Subjects were performed bridge exercise on 4 different shoulder support surfaces using stable and labile instruments. 1) Bridge exercise on a stable surface. 2) Bridge exercise with their shoulder on a stable bench. 3) Bridge exercise with their shoulder on a sling. 4) Bridge exercise with their shoulder on a Swiss ball. Rectus abdominis, erector spinae, internal oblique, external oblique muscle activities were measured using electromyography. RESULTS: There were significant differences in RA, EO muscles between performing each of the 4 exercises(p<.05). RA and EO was recorded the highest activity during the bridge exercise with their shoulder on a sling. The lowest activity was recorded during conventional supine bridge on a stable surface. There were no differences found for the EO/RA and IO/RA ratio. The EO/RA and IO/RA ratio was the highest in the bridge exercise with their shoulders resting on a stable bench. CONCLUSION: These findings suggest that change of shoulder support surface during bridge exercise may be useful for enhancing the trunk stability.

• Journal of the Korean Professional Engineers Association
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• v.33 no.3
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• pp.71-79
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• 2000

The effects of alkali salts adding on the cooking quality improving in dried noodles were investigated in the good texture maintaining for preventing solid soluble losses ,through chemical analysis and actual manufacturing practice ,the following results were obtained. Experiments were took a special flour of ASW:DNS=70:30, thickening agent(TA) composed of K2CO3 58%, Na2CO3 36% and Na4P2076%, and emulsified oil(EO) mixing of corn oil 44%, polysorbate 23%, emulsifier(ester of glycerin and fatty acids) 21%, soy lecithin 12%. When the mixing ratio of TA and EO to flour, is 0.03 and 1.5%(w/w) or morel than, satisfied the good quality. The water soluble solid matters content of the lowest 3.2% in the treating group that TA and EO is 0.03 and 1.5%(w/w) respectively, comparing to the 7.3% in the control group provides a excellent cooking quality. The research achieves the similar effects at specific gravity, water absorption ratio, weight increasing rate and volume expansion ratio. According to appearance test the more treating of TA turn the noodle into deeper yellow-green color. Turning to the deeper yellow color according to the increasing of EO provides better

• Bulletin of the Korean Chemical Society
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• v.26 no.11
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• pp.1653-1668
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• 2005

Assembly of hybrid mesophases through the combination of amphiphilic block copolymers, acting as structuredirecting agents, and silicon sources using low acid catalyst concentration regimes is a versatile strategy to produce large quantities of high-quality ordered large-pore mesoporous silicas in a very reproducible manner. Controlling structural and textural properties is proven to be straightforward at low HCl concentrations with the adjustment of synthesis gel composition and the option of adding co-structure-directing molecules. In this account, we illustrate how various types of large-pore mesoporous silica can easily be prepared in high phase purity with tailored pore dimensions and tailored level of framework interconnectivity. Silica mesophases with two-dimensional hexagonal (p6mm) and three-dimensional cubi (Fm$\overline{3}$m, Im$\overline{3}$m and Ia$\overline{3}$d) symmetries are generated in aqueous solution by employing HCl concentrations in the range of 0.1−0.5 M and polyalkylene oxide-based triblock copolymers such as Pluronic P123 $(EO_{20}-PO_{70}-EO_{20})$ and Pluronic F127 $(EO_{106}-PO_{70}-EO_{106})$. Characterizations by powder X-ray diffraction, nitrogen physisorption, and transmission electron microscopy show that the mesoporous materials all possess high specific surface areas, high pore volumes and readily tunable pore diameters in narrow distribution of sizes ranging from 4 to 12 nm. Furthermore, we discuss our recent advances achieved in order to extend widely the phase domains in which single mesostructures are formed. Emphasis is put on the first synthetic product phase diagrams obtained in $SiO_2$-triblock copolymer-BuOH-$H_2O$ systems, with tuning amounts of butanol and silica source correspondingly. It is expected that the extended phase domains will allow designed synthesis of mesoporous silicas with targeted characteristics, offering vast prospects for future applications.

• Restorative Dentistry and Endodontics
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• v.27 no.4
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• pp.411-420
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• 2002

The aim of this study is to compare the adaptability of thermoplasticized injectable gutta-percha technique to the canal walls in ribbon-shaped canals. Thirty resin models simulated ribbon-shape canals were instrumented to #40 using .06 taper Profile systems. Three groups of each 10 resin models were obturated by the lateral condensation technique(LC) and the two thermoplasticized injectable gutta-percha technique; Ultrafil Endoset+Obtura II(EO) and Ultrafil Firmset(UF), respectively. After resin model were kept at room temperature for 4 days, they were resected horizontally with micro-tome at 1, 2, 3, 4 and 5mm levels from apex. At each levels. image of resected surface were taken using CCD camera under a stereomicroscope at $\times$40 magnification and stored. Ratio of the area of gutta-percha was obtained by calculating area of gutta-percha cone to the total area of canal using digitized image-ana-Iyzing program. The data were collected then analyzed statistically using One-way ANOVA. The results were as follows. 1 At 1mm levels, there was no statistically significant difference in the mean ratio of gutta-percha among the groups. 2. At 2mm level, EO showed the highest mean ratio of gutta-percha (p<0.05) and there was no significant difference between LC and UF. 3. At 3, 4, 5mm levels, EO and UF had significantly greater mean ratio of gutta-percha than LC(p<0.05) and there was no significant difference between EO and UF. In conclusion, the thermoplasticized injectable gutta-percha techniques demonstrated relatively favorable adaptability to canal walls than lateral condensation technique in ribbon-shaped canals except for 1mm level.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• v.23 no.1
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• pp.79-88
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• 2020

Purpose: Management of eosinophilic esophagitis (EoE) varies from center to center. In this study, we evaluated the effectiveness of a dairy-free diet (DFD) and the 6-Food Elimination Diet (SFED) as initial therapies for the treatment of EoE in our practice. Methods: This was a retrospective study of children who had been treated for EoE at Connecticut Children's Medical Center, Hartford, CT, USA. Pre- and post-treatment endoscopy findings and histology results of patients treated with DFD or SFED were examined. Results: One hundred fifty-two patients (age 9.2±5.2 years, 76.3% male, 69.7% caucasian) met the inclusion criteria for initial treatment with DFD (n=102) or SFED (n=50). Response for DFD was 56.9% and for SFED was 52.0%. Response based on treatment duration (<10, 10-12, and >12 weeks) were 81.8%, 50.0%, and 55.1% for DFD, and 68.8%, 50.0%, and 40.0% for SFED. Response based on age (<6, 6-12, and >12 years) were 59.3%, 42.9%, and 67.5% for DFD, and 36.4%, 58.8%, and 72.7% for SFED. In patients treated with DFD, concomitant proton pump inhibitor (PPI) administration resulted in improved outcomes (p=0.0177). Bivariate regression analysis showed that PPI with diet is the only predictor of response (p=0.0491), however, there were no significant predictors on multiple regression analysis. Conclusion: DFD and SFED are effective first line therapies for EoE. DFD should be tried first before extensive elimination diets. Concomitant therapy with PPI's may be helpful.

• PNF and Movement
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• v.13 no.1
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• pp.25-30
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• 2015

Purpose: The aim of this study was to examine the effects of abdominal muscle contraction thickness using real-time ultrasound imaging while applying an abdominal draw-in maneuver (ADIM) and pelvic floor muscle contraction (PFC) to low back pain patients and healthy subjects. Methods: The subjects were 21 young adults; a group of 10 low back pain patients and a control group of 11 healthy subjects. Measurements were made with the subjects on a pillow in a supine position, with the knee joints flexed at 60 degrees. While the two groups conducted ADIM and PFC, their transverse abdominal muscle (TrA), internal abdominal oblique muscle (IO), and external abdominal oblique muscle (EO) thicknesses were measured using an ultrasound imaging system. Result: The TrA muscle contraction thickness ratio during PFC and ADIM was significantly lower in the low back pain group than in the healthy group (p<0.05). The EO muscle contraction thickness ratio during ADIM was also significantly lower in the low back pain group than in the healthy group. The healthy group's muscle contraction thickness ratio was significantly lower during PFC than during ADIM in the TrA, IO, and EO (p<0.05). The low back pain group's muscle contraction thickness ratio was lower during PFC than during ADIM in the TrA, IO, and EO, but the difference was not statistically significant. Conclusion: The results of this study indicate that oral direction during ADIM induced an appropriate contraction of the TrA. Therefore, the procedure reported here may be applied during rehabilitation for appropriate contraction of the TrA.