• Journal of Korean Biological Nursing Science
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• v.10 no.1
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• pp.88-95
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• 2008

Purpose: The purpose of this study was to examine the effect of neuropathic pain by peripheral nerve injury on mass and Type I and II fiber cross-sectional areas on hindlimb muscles of the neuropathic pain model rat. Method: Adult male Sprague-Dawley rats (body weight 200-220 g) were assigned to one of two groups: a neuropathic pain group (n=7) that had a ligation of the left L5 spinal nerve, a control group (n=5), a naive rat without any procedures. Withdrawal threshold, activity, body weight and food intake were measured daily. At 8 days after neuropathic pain, all rats were anesthetized and the soleus and plantaris muscles were dissected from the both hindlimbs. Body weight, food intake, muscle weight and Type I and II fiber cross-sectional area of the dissected muscles were determined. Result: The neuropathic pain group showed a significant decreases (p<.05) as compared with the control rats, in diet intake, body weight, muscle weight and Type II fiber cross-sectional area of the left (affected side) soleus and plantaris muscles, and the right (unaffected side) muscle weight of plantaris and Type II fiber cross-sectional area of the soleus muscle. Conclusion: The hindlimb muscle atrophy occurs in both affected and unaffected side due to neuropathic pain by the peripheral nerve injury. The hindlimb muscle atrophy of the affected side is more pronounced than that of the unaffected side.

• Journal of Korean Biological Nursing Science
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• v.4 no.1
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• pp.85-99
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• 2002

This study was conducted to determine whether low intensity regular exercise following steroid treatment could attenuate steroid-induced muscle atrophy. Thirty-eight Sprague-Dawley rats weighing $165{\sim}175g$ were divided into six groups ; control group(C), dexamethasone administration group(D), sedentary normal saline administration group(C+Se), exercise after normal saline administration group(C+Ex), sedentary group after dexamethasone administration(D+Se), exercise group after dexamethasone administration(D+Ex). Either dexamethasone(5mg/kg) or normal saline was injected for 7days accordingly. Exercise was started at 10m/min on the $10^{\circ}$ grade treadmill and gradually increased up to 15m/min by the 7th day for 60minutes/day($20min{\times}3$). The data were analyzed by Kruskal-Wallis test and Mann-Whitney U test using the SPSS WIN 9.0 program. Body weight, muscle weight and myofibrillar protein content of both plantaris and gastrocnemius, Type I, II muscle fiber cross-sectional area of plantaris, and Type II muscle fiber cross-sectional area of gastrocnemius in D group were significantly lower than those of C group(p<0.05) respectively. Hindlimb muscle weight, myofibrillar protein content of both plantaris and gastrocnemius. Type I muscle fiber cross-sectional area of soleus and Type I, II muscle fiber cross-sectional area of plantaris in D+Ex group tended to increase compared to those of D+Se group. Myofibrillar protein content of both plantaris and gastrocnemius, Type I muscle fiber cross-sectional area of plantaris in D+Ex group tended to increase compared to those of C+Se group. Based on these results, it is suggested that regular low-intensity exercise during recovery period after steroid treatment might facilitate the recovery from steroid-induced muscle atrophy.

• Proceedings of the KSME Conference
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• 2004.11a
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• pp.1454-1459
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• 2004

The major parameters governing the fluid dynamical and thermo-dynamical behavior in the large pipeline network system are friction loss and the pipeline length. But in local pipeline networks and relatively short distance pipeline system, secondary loss and the considerations of the moving states of the fluid machine are also important. One of the major element in local pressure control system is pressure regulator. It causes the variations of the physical properties in that pipeline system. When it is under working, the accurate analysis of the flow properties is so difficult. In this study, some numerical approaches to investigate the critical-flow-characteristics of the pressure regulator have been done according to the variations of the opening ratio or cross-sectional area and the detail examinations and considerations of the pressure regulator as a pipeline network elements have been carried. Finally the flow-flied distributions and critical-flow-characteristics have been presented in detail and the critical flow phenomena and the relation to the opening ratio or cross-sectional-area ratio have been studied.

• Clinics in Shoulder and Elbow
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• v.19 no.3
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• pp.155-162
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• 2016

Background: The study aimed to determine the type of capsular insertion and the extent of capsular elongation in anterior shoulder instability by quantitatively evaluating their computed tomography arthrographic (CTA) findings, and to investigate the correlation of these parameters with surgical outcomes. Methods: We retrospectively reviewed 71 patients who underwent CTA and arthroscopic capsulolabral reconstruction for anterior shoulder instability between April 2004 and August 2008. The control group comprised 72 patients diagnosed as isolated type II superior labrum anterior to posterior (SLAP) lesion during the period. Among the 143 patients, 71 were examined with follow-up CTA at an average 13.8 months after surgery. It was measured the capsular length and cross-sectional area at two distinct capsular regions: the 4 and 5 o'clock position of the capsule. Results: With regards to the incidence of the type of anterior capsular insertion, type I was more common in the control group, whereas type III more common than in the instability group. Anterior capsular length and cross-sectional area were significantly greater in the instability group than in the control group. Among patients of the instability group, the number of dislocations and the presence of anterior labroligamentous periosteal sleeve avulsion lesion were significantly associated with anterior capsular redundancy. Postoperatively, recurrence was found in 3 patients (4.2%) and their postoperative capsular length and cross-sectional area were greater than those of patients without recurrence. Conclusions: Capsular insertion type and capsular redundancy derived through CTA may serve as important parameters for the management of anterior shoulder instability.

• Journal of Convergence for Information Technology
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• v.11 no.10
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• pp.223-229
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• 2021

This study analyzed the effects of an exercise program that combined lumbar stabilization exercise and muscle strengthening exercise and an exercise program that applied only lumbar muscle strengthening exercise on multifidus muscle cross-sectional area, static posture control ability, and low back pain in patients with CLBP. For the study method, 28 patients with CLBP were divided into two exercise propram groups and exercised three times a week for 8-weeks. The data analysis of this study used the t-test to compare before and after group exercise program application, and between each group (p<.05). As a result of the study, significant results were found before and after application of the exercise program within each group, such as multifidus muscle cross-sectional area, static posture control ability, and low back pain (p<.05). Between each group, the exercise program that combined lumbar stabilization exercise and muscle strengthening exercise was found to be more effective (p<.05). In conclusion, it was found that the exercise program with additional lumbar stabilization exercise improved the structure and function of various lumbar vertebrae and reduced lumbar pain.

• Restorative Dentistry and Endodontics
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• v.29 no.3
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• pp.267-272
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• 2004

The purpose of this in vitro study was to evaluate the effect of surface defects and cross-sectional configuration of NiTi rotary files on the fatigue life under cyclic loading. Three NiTi rotary files ($K3^{TM},{\;}ProFile^{\circledR},{\;}and{\;}HERO{\;}642^{\circledR}$) with ＃30/.04 taper were evaluated. Each rotary file was divided into 2 subgroups : control (no surface defects) and experimental group (artificial surface defects), A total of six groups of each 10 were tested. The NiTi rotary files were rotated at 300rpm using the apparatus which simulated curved canal (40 degree of curvature) until they fracture. The number of cycles to fracture was calculated and the fractured surfaces were observed with a scanning electron microscope. The data were analyzed statistically. The results showed that experimental groups with surface defects had lower number of cycles to fracture than control group but there was only a statistical significance between control and experimental group in the $K3^{TM}$ (p<0.05), There was no strong correlation between the cross-sectional configuration area and fracture resistance under experimental conditions. Several of fractured files demonstrated characteristic patterns of brittle fracture consistent with the propagation of pre-existing cracks. This data indicate that surface defects of NiTi rotary files may significantly decrease fatigue life and it may be one possible factor for early fracture of NiTi rotary files in clinical practice.

• Korean Journal of Radiology
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• v.1 no.3
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• pp.127-134
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• 2000

Objective: To determine the extent to which thin-section and volumetric three-dimensional CT can depict airway reactivity to bronchostimulator, and to assess the effect of different airway sizes on the degree of reactivity. Materials and Methods: In eight dogs, thin-section CT scans were obtained before and after the administration of methacholine and ventolin. Cross-sectional areas of bronchi at multiple levels, as shown by axial CT, proximal airway volume as revealed by three-dimensional imaging, and peak airway pressure were measured. The significance of airway change induced by methacholine and ventolin, expressed by percentage changes in cross-sectional area, proximal airway volume, and peak airway pressure was statistically evaluated, as was correlation between the degree of airway reactivity and the area of airways. Results: Cross-sectional areas of the bronchi decreased significantly after the administration of methacholine, and scans obtained after a delay of 5 minutes showed that normalization was insufficient. Ventolin induced a significant increase in cross-sectional areas and an increase in proximal airway volume, while the effect of methacholine on the latter was the opposite. Peak airway pressure increased after the administration of methacholine, and after a 5-minute delay its level was near that of the control state. Ventolin, however, induced no significant decrease. The degree of airway reactivity did not correlate with airway size. Conclusion: Thin-section and volumetric spiral CT with three-dimensional reconstruction can demonstrate airway reactivity to bronchostimulator. The degree of reactivity did not correlate with airway size.

• Journal of the Korean Society for Precision Engineering
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• v.19 no.10
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• pp.45-51
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• 2002

To achieve the lightweight and robust design of a structure, it is requested to design a structure and its control system simultaneously, which is called as the combined optimal design. A constant-cross-sectional area cantilever beam was chosen as an example for the applying the optimum design method. An initial load and a time varying disturbance were applied at the free end of the beam. Sliding mode control was selected due to its insensitiveness to the disturbance compared with other modes. It is known that the sliding mode control is robust to the disturbance and the uncertainty only if a matching condition is met, after giving a switching hyper plane. In this study, the optimum method was used for the design of the switching hyper plane and the objective function of the optimum switching hyper plane was assumed to be the objective one of the control system. The total weight of the structure was treated as a constraint and the cross sectional areas of the beam were considered as design variables, which means a nonlinear programming problem. The sequential linear programming method was applied to solve it. As a result of the optimum design, the effect of attenuating vibrations has been improved obviously. Moreover, lightweight design of the structure became possible from the relationship of the weight of the structure and the control objective function.

• Journal of Ocean Engineering and Technology
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• v.17 no.4
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• pp.59-65
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• 2003

In order to achieve the desired lightweight and robust design of a structure, it is preferable to design a structure and its control system, simultaneously, which is termed the combined optimal design. A constant-cross-sectional area cantilever beam was chosen as the optimum design method, An initial load and a time-varying disturbance were applied at the free end of the beam. Sliding mode control was selected, due to its insensitivity to the disturbance, compared with other modes. It is known that the sliding mode control is robust to the disturbance and is uncertain, only if a matching condition is met, after giving a switching hyper plane. In this study, the optimum method was used for the design of the switching hyper plane, and the objective function of the optimum switching hyper plane was assumed to be the objective of the control system. The total weight of the structure was treated as a constraint, and the cross sectional areas of the beam were considered as design variables, the result being a nonlinear programming problem. To solve it, the sequential linear programming method was applied. As a result of the optimum design, the effect of attenuating vibrations has been substantially improved. Moreover, the lightweight design of the structure became possible as a result of the relationship of the weight of the structure to the control objective function.

• Korean Journal of Applied Biomechanics
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• v.25 no.4
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• pp.371-381
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• 2015

Object : The purpose of this study was to investigate aging-related changes of intrinsic and extrinsic hand muscles in their strength, cross-sectional area and volume, force control, and multi-digit synergies. It was hypothesized that aging would negatively affect distal muscles (intrinsic muscles) more than proximal muscles (extrinsic muscles). Method : Nine young and eleven older right-handed participants underwent MRI scans of the hand and forearm. Muscle cross-sectional areas and volumes of the intrinsic and extrinsic hand muscles were determined. Result : Muscle volume of the intrinsic muscles were larger in the younger group than the older group while muscle volume of the extrinsic muscles did not differ. For the cross-sectional area, both the intrinsic and extrinsic muscles of the younger group were larger than the older group. The maximum strength of the intrinsic muscles of the young group was 31% greater than the older group ($399.1{\pm}26.4$ vs $270.2{\pm}22.9Ncm$, p < 0.05) while the extrinsic muscles showed no significant difference. Although the elderly group showed a trend of decreased force control and multi-digit synergies, no statistical differences were found. These findings indicate aging-related decreases in hand muscle size and strength affect intrinsic muscles more than extrinsic muscles, thus supporting the hypothesis that sarcopenia affects the muscle size and strength of distal muscles more than proximal muscles. Conclusion : The aging-related decreases in hand muscle size and function were more apparent in intrinsic hand muscles, located more distally, than extrinsic muscles, located more proximally.