• Korean Journal of Biological Psychiatry
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• v.25 no.3
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• pp.60-71
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• 2018

Objectives A growing body of evidence has suggested that morphologic changes in cerebellum may be implicated with pathophysiology of major depressive disorder (MDD). The aim of this study is to investigate a difference in the volume and cortical thickness of the specific region of cerebellum between patients with MDD and healthy controls (HC). Methods A total of 127 patients with MDD and 105 HC participated in this study and underwent T1-weighted structural magnetic resonance imaging. We analyzed volume and cortical thickness of each twelve cerebellum regions divided by left and right and the volume and cortical thickness of the whole cerebellum from T1-weigted image of participants. One-way analysis of covariance was used to investigate the volume and cortical thickness difference of total and specific regions between two groups adjusting for age, gender, medication, and total intracranial cavity volume. Results We found that the patients with MDD had significantly greater volume in the left cerebellum lobule III region [false discovery rate (FDR)-corrected p = 0.034] compared to HC. Also, our findings indicate that cortical thickness of left lobule VIIB (FDR-corrected p = 0.032) and lobule VIIIB (FDR-corrected p = 0.032) are significantly thinner in the patients with MDD compared with the HC. No significant volume and cortical thickness differences were observed in other sub-regions of the cerebellum. The volumes and cortical thickness of whole cerebellum between patients with MDD and HC did not differ significantly. Conclusions We observed the region-specific volume and cortical thickness difference in cerebellum between the patients with MDD and HC. The results of our study implicate that the information about structural alterations in cerebellum with further replicative studies might provide a stepping stone toward a specific marker to diagnose MDD.

• Korean Journal of Applied Biomechanics
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• v.22 no.3
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• pp.349-356
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• 2012

This study aimed to assess the effects of progressive lumbar stability exercises and lumbar stability exercises on changes in the transversus abdominis muscle thickness and lower extremity muscle fatigue index in soccer players. Ten subjects were assigned to undergo training in each of the 2 groups, namely, the progressive lumbar stability exercise group and lumbar stability exercise group. Each intervention session lasted for 30 min, and 4 sessions were conducted in a week for 6 weeks for soccer players of S. University in Jeonnam, Korea. Changes in the transversus abdominis muscle thickness and lower extremity muscle fatigue index were measured using ultrasound and surface electromyogram. The results of the ultrasound measurement for the transversus abdominis muscle thickness indicated that progressive lumbar stability exercises were more effective than lumbar stability exercises. The results of the lower extremity muscle fatigue index measurements using surface electromyogram indicated that the fatigue index decreased in the progressive lumbar stability exercise group. Progressive lumbar stability exercise is believed to have put more workload during the shaking of the limbs, leading to increased stability and increased efficiency of the lower extremity muscle, thereby decreasing the fatigue index. Therefore, progressive lumbar stability exercises can be an effective measure for preventing injuries and improving the game performance of sports players by increasing the transversus abdominis muscle thickness and decreasing the lower extremity muscle fatigue index.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.41 no.9
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• pp.623-629
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• 2017

Flow structure and mixing characteristics in a micro combustor with a multi-hole baffle were numerically studied using the Reynolds stress model. The multi-hole baffle has geometrical features to produce multiple three-dimensional vortices inside combustion chamber. When the thickness of the baffle's geometrical factors changes, variations of vortical structures occur variously. Among these vortices, the vortex generated from the fuel stream exerts a critical influence on the mixing enhancement. The three-dimensional vortical structure, in its development state, was strongly dependent on the baffle thickness. In particular, as the baffle thickness decreases to values less than the diameter of the fuel hole, the jet stream in baffle holes changes from the parabolic to saddleback profile type. The sizes of recirculation zones inside combustion chamber and the mixing state were closely affected by the structure of the jet streams.

• Physical Therapy Korea
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• v.27 no.1
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• pp.87-92
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• 2020

Background: Bridging exercises are used to enhance the functional stability of the lumbopelvic region in clinical settings. Although most of the studies on bridging exercises have compared the complete activation of the trunk muscles, some recent studies have examined the functional stability of the trunk and the lumbopelvic region and assessed the appropriate recruitment of the local and global muscles during different task levels. Objects: The purpose of this study was to investigate the changes in muscle thickness in the transverse abdominis (TrA), internal oblique (IO), and external oblique (EO) muscles during a common bridging exercise on an unstable surface and to determine whether these changes differ based on the surface used. Methods: Twenty-five healthy young adults (8 males, 17 females) were recruited. The subjects were randomly assigned to either the exercise progression with a sling bridge group or the ball bridging exercise progression group, each with three stages of increasing difficulty. Each position was measured three times with an ultrasonic diagnostic imaging system, and the mean values were recorded for analysis. Results: No significant differences were observed between the TrA, IO, or EO muscle thickness ratios between the sling and ball exercise groups (p > 0.05). There were also no significant differences in the EO muscle thickness ratios between the tasks irrespective of whether the sling or ball was used. However, the TrA and IO thickness ratios in both groups were significantly greater during stages 2 and 3 compared to stage 1. Conclusion: The results suggest that the use of slings and balls during bridging exercises is effective in activating the deep abdominal muscles.

• Journal of The Korean Society of Integrative Medicine
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• v.7 no.2
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• pp.121-131
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• 2019

Purpose : Lower back pain is a common disorder experienced by approximately 90-% of the population at least once in a lifetime. This study examines changes in the thicknesses and ratios of the deep and superficial fibers of the multifidus according to the lumbar stabilization exercise used for spinal stabilization. Methods : Ten different lumbar stabilization exercises were implemented by 20 healthy men in random order, and the thickness of multifidus muscle was measured ultrasound image during each exercise. Results : The surface muscle fibers of the multifidus muscles significantly increased in the exercise method in which the arms and legs were lifted (p<.05), while the deep muscle fibers of the multifidus muscles increased significantly in the exercise in which the arms and legs were not lifted (p<.05). The ratio of the thickness of surface muscle fibers to the total thickness of muscle fibers was higher in the exercise method in which the arms and legs were lifted (p<.05), while the ratio of the thickness of deep muscle fibers to the total thickness of muscle fibers was higher in the hollowing and bracing exercise method in which the arms and legs were not lifted (p<.05). Conclusion : When lumbar stabilization exercise should be performed at clinics to strengthen the deep muscle fibers of the multifidus muscles that have larger effects on the stability of spinal segments, taking the stability of the spine into consideration indicates that, hollowing and bracing exercise methods that do not that cause isotonic extension to the spine are appropriate.

• Archives of Craniofacial Surgery
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• v.23 no.3
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• pp.103-110
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• 2022

Background: The primary objectives of mandibular surgery are to achieve optimal occlusion, low sensory disturbance, and adequate fixation with early movement. In-depth knowledge of the mandibular structure is required to achieve these goals. This study used computed tomography (CT) to evaluate the mandibular cortical thickness and cancellous space according to age and sex. Methods: We enrolled 230 consecutive patients, aged 20 to 50 years, who underwent CT scanning. The cortex and cancellous space centered around the inferior alveolar nerve (IAN) canal were measured at two specific locations: the lingula and second molar region. Statistical analysis of differences according to increasing age and sex was performed. Results: The t-test revealed that the cancellous space and cortical thickness differed significantly with respect to the threshold of 35 years of age. Both cortical thickness and cancellous space in the molar region were negatively correlated with age. Meanwhile, both cortical thickness and cancellous space in the lingula region showed a positive correlation with age. With respect to sex, significant differences in the cancellous space at the molar region and the cortical thickness at the lingula were observed. However, no further statistically significant differences were observed in other variables with respect to sex. The sum of each measurement on the mandibular body reflected the safe distance from the surface of the outer cortex to the IAN canal. The safe distances also showed statistically significant differences between those above and below 35 years of age. Conclusion: Knowledge of the anatomical structure of the mandible and of changes in bone structure is crucial to ensure optimal surgical outcomes and avoid damage to the IAN. CT examination is useful to identify changes in the bone structure, and these should be taken into account in the planning of surgery for older patients.

• Journal of the Korean Home Economics Association
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• v.36 no.5
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• pp.17-27
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• 1998

The need for periodic investigation on human growth rate and somatotypes has been increased because the scientific development and environmental factors have effected a lot on them recently. This study aimed to investigate the changes of the 638 female somatotypes in the age of 18-54 obtained by direct and indirect measurement. The measurement data were divided into 4 groups early young women age group (18-54), late young women age group (25-34), early middle age group (35-44), late middle age group (45-54) and compared each other based on each group by age. The results obtained from this study were as follows: 1. According to Mollison Curve based on the early young women, items of depth decreased overall and pp.P. length & shoulder length increased as the age increased. The circumference, breadth and thickness tended to increase, especially waist girth and thickness of waist increased markedly. The data showed that the increase rate of thickness was higher than that of breadth. 2. Gradual somatotype changes were observed by overlapping projection drawings obtained by direct measurement. Compared with the young women, the middle aged showed lower should point depth and hip line & crotch depth line were lengthened significantly. No significant difference was observed in overlapping of the early young women and the late young women' figure, neither was in early middle aged and the late middle aged. 3. By overlapping the side view of the young women group (18-37) and middle aged group (35-54), no significant postural characteristics were found, while the back tended to bend forward and the abdomen and hip appeared to get fat.

• Advances in pediatric surgery
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• v.5 no.1
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• pp.64-68
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• 1999

The length, diameter and muscle thickness of the pylorus were measured by ultrasonograms in 15 infants with infantile hypertrophic pyloric stenosis(IHPS). These measurements were compared to assemble measurements of infants who came in for the routine vaccination and underwent ultrasonogram. This study also studied by ultrasound the changes in the pylorus of patients who underwent pyloromyotomy 4 weeks and 8 weeks postoperatively. According to $Carver^5$, the pyloric muscle volume(PMV) and pyloric muscle index(PMI) were calculated in each case. The pyloric muscle volume, PMI and the thickness of pyloric muscle proved to be a more reliable guide to diagnose IHPS than length and diameter of pylorus. The pyloric muscle length, diameter, thickness and pyloric muscle volume were not normalized at 4 and 8 weeks after pyloromyotomy. However, pyloric muscle index was normalized at 4 weeks postoperatively perhaps as the result of rapid weight gain after pyloromyotomy.

• Tribology and Lubricants
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• v.31 no.5
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• pp.205-212
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• 2015

In this research, effects of profile changes of stem section of the plunger on the lubrication characteristics of a fuel injection pump (FIP) were evaluated by hydrodynamic lubrication analysis. The clearance between plunger and barrel was divided into two regions, head and stem. The head was not involved in preventing a decrease of fuel oil pressure. So, research efforts were focused on both edges of the plunger’s stem. The two -dimensional Reynolds equation was used to evaluate lubrication characteristics with variations in viscosity, clearance and profile for a laminar, incompressible, unsteady-state flow. Moreover, the equilibrium equation of moment and forces in the vertical and horizontal directions were used to determine the motion of the plunger. The equations were discretized using the finite difference method. Lubrication characteristics of the FIP were investigated by comparing the dimensionless minimum film thickness, or film parameter, which is the ratio of minimum film thickness to surface roughness. Through numerical analyses, we showed that the profile of the lower edge of the stem had no effect on lubrication characteristics, but the profile of the upper edge had a significant influence on lubrication characteristics. In addition, changes in the profile were more effective in improving lubrication characteristics under low viscosity conditions.

• Journal of Forest and Environmental Science
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• v.30 no.2
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• pp.226-232
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• 2014

To understand transition characteristics from wood to charcoal the dimensional changes of carbonized woods at low temperature from $300^{\circ}C$ to $350^{\circ}C$ at the intervals of $10^{\circ}C$ were investigated. Three species of hardwoods and two species of softwoods were used in this study. Measurements of dimensional changes of cells were observed by stereoscopic microscope and an image analyzer. The apparent volume of each specimen decreased greatly with increasing temperature. Severe cracks and collapse were observed frequently in hardwoods and hardly in softwoods. Vessel diameter and tracheid cell wall thickness of the wood samples were decreased with increasing carbonization temperature. Contraction of vessel diameter in tangential direction was greater than that in radial direction. Cell wall thickness of tracheids decreased with increasing carbonization temperature. Consequently, even though it was small range of carbonization temperature, dimensions of wood components were changed considerably.