• The Journal of Korean Physical Therapy
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• v.10 no.1
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• pp.81-98
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• 1998

Isokinetic evaluation of trunk flexors and trunk extensors was performed at $60^{\circ}/sec\;and\;120^{\circ}/sec$ of angular velocity by using cybex 6000TEF Unit on 31 healthy male white workers and 15 post-operative HILD patients with no significant difference in mean age and mean body weight between two groups, and compared each other. The purpose of this study is to obtain the isokinetic normative strength values and endurance latins for Dunk extensors and trunk flexors, and is to provide a guideline for rehabilitation program of post-operative HILD patients. The collected data were analyzed by ANOVA, Duncan's Nyktuoke Range Test, and Pearson correlation coefficiency in PC-SAS program, The results obtained were as follow ; 1. Post-operative subjects has lower isokinetic values than normal subjects in peak torque, peak torque $\%$ by body weight, total work, total work $\%$ by body weight, average power, average power $\%$ by body weight, TAAE of trunk flexors and trunk extensors, and there are significant differences with statistic value in trunk extensors at $60^{\circ}/sec$ and in trunk flexors and trunk extensors at $120^{\circ}/sec$ between two groups(p<0.05). 2. Pest-ooperative subjects has lower values for angle of peak torque than normal subjects in trunk extensors, and there are significant differences with statistic value at $60^{\circ}/sec$ and $120^{\circ}/sec$ between two groups. 3. Post-operative subjects has higher values for endurance ratios than normal subjects in trunk extensors and flexors, but there are no significant differences with statistic value between two groups. 4. Post-operative subjects has higher values than normal subjects in peak torque ratios, total work ratios, average power ratios of trunk flexors to trunk extensors, and there are significant differences with statistic value between two groups(p<0.01). 5. There is significant positive-correlation with statistic valve between peak torque and height and body weight in normal subjects(p<0.05), but Thjere is significant negative-correlation between peak torque of trunk extensor at $120^{\circ}/sec$ and age (p<0.05). 6. There is significant positive-correlation with statistic value between peak torque of trunk flexors and body weight in post-operative subjects (p<0.05), but There is significant negative-correlation between peak torque of trunk extensor add age (p<0.05). In conclusion, post-operative subjects have greater weakness in trunk musculature than normal subjects, especially there is more significant weakness in trunk extensors than in trunk flexors

• The Journal of Internal Korean Medicine
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• v.33 no.1
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• pp.26-38
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• 2012

Objectives : The aim of this study was to investigate the effect of partial pyloric obstruction on body weight, gastric juice, gastric surface area and gastric edema in normal intact and/or vagotomized rats. Methods : Partial pyloric obstruction was performed by wrapping a non-absorbable rubber ring (D:6 mm, W:4 mm, T:1 mm) around the 1st portion of the duodenum. Vagotomy was performed by resecting the branches around the esophagogastric junction. Pre-post body weight differential, fasting gastric juice volume, gastric surface area and gastric edema were measured at 8 weeks and 20 weeks. For the effect of pyloric reperfusion the rubber ring was removed after 8 weeks and then an additional 12 weeks of observation was performed to the end of the 20-week experimental period. Results : In the initial 8 weeks observation, the effect of pylorus obstruction and/or vagotomy was significantly remarkable in the pylorus obstructed and vagotomized group; slowdown of weight gain, increase of fasting gastric juice volume, dilatation of gastric surface area and severe gastric edema were shown. In the remaining 12 weeks observation, the effect of reperfusion was significantly remarkable in the ring-removed antral dilated group; recovery of weight gain, decrease of gastric surface area and decrease of gastric edema were shown. However, gastric juice volume was not significantly different from the other group. Conclusions : Partial pyloric obstruction plays a aggravating role and the vagus nerve plays a protective role in body weight, gastric juice, gastric surface area, and gastric edema. Furthermore, pyloric valve dysfunction as an aggravating factor strengthened in defect of the vagus nerve. These results suggest that patients with both functional pyloric outlet obstruction and hypofunction of vagus nerve need to be diagnosed in good time and treated properly.

• Journal of Chest Surgery
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• v.43 no.6
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• pp.614-618
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• 2010

Background: The aim of our study was to assess the extent of regression of left ventricular mass after aortic valve replacement in isolated aortic regurgitation. Material and Method: Retrospective analysis of echocardiographic data was collected preoperative and postoperative 1 year. There were 20 patients (12 males, 8 females, mean age $55.8{\pm}11.8$ years, mean body surface area $1.64{\pm}0.19m^2$) with aortic regurgitation from 2002 through 2007. We studied the change of left ventricular ejection fraction, ventricular septum and left ventricular posterior wall thickness, and left vemtricular muscle index (LVMI). The control group was age matched with normal echocardiographic study results. Patients with combined surgery or infective endocarditis were excluded. Result: Seven cases of tissue valves and thirteen cases of mechanical valve were used. The valve sizes were 21 mm (3 cases), 23 mm (13 cases) and 25 mm (4 cases). The postoperative ($125.5{\pm}42g/m^2$) LVMI has decreased than preoperative LVMI ($212.3{\pm}80g/m^2$, p=0.000) but higher than that of control group ($80.5{\pm}15.9g/m^2$, p=0.000). Postoperative septal wall (systolic/diastolic: $13.5{\pm}3.4mm/17.1{\pm}4.1mm$) and left ventricular posterior wall (systolic/diastolic: $12.9{\pm}3.4mm/16.7{\pm}3.4mm$) thickness were slightly decreased after the valve replacement but was not significantly different than preoperative levels. And postoperative interventricular septal wall and left ventricular posterior wall thickness (systolic/diastolic: $8.6{\pm}1.4mm/12.1{\pm}1.7mm$, systolic/diastolic: $8.4{\pm}1.4mm/13.2{\pm}1.9mm$) were higher than that of the control group (p<0.001). Conclusion: The significant regression of LVMI after aortic valve replacement developed at postoperative one year but the level was higher than control group. The main cause of decreased LVMI is decreased in left ventricular dimension.

• Journal of Chest Surgery
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• v.25 no.1
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• pp.32-41
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• 1992

From August 1982 to December 1991, 58 consecutive infants with tetralogy of Fallot underwent primary repair. Age ranged from 22 days to twelve months [n=58, 8.7$\pm$2.7 months] and body weight from 3.1 to 13 kilograms [n=58, 7.8$\pm$1.7 kilograms]. Qne infant had absence of the pulmonary valve; one had Ebstein`s anomaly and one had supramitral ring. Thirty-two patients [56%] experienced anoxic spell. Preoperative pulmonary artery indices were measured in 38 cases, ranging 126-552mm2/M2BSA[n=38, 251$\pm$79mm2/M2BSA]. All infants required a right ventricular outflow tract patch; in 41, the patch extended across the pulmonary valve annulus, in 13 of them, monocusps were constructed. All had patch closure of ventricular septal defect. Two infants had REV operation for avoiding injury to the canal branch of the right coronary artery which cross the right ventricular out flow tract. Post repair PRV/LV were measured at operating room in 40 cases, which revealed mean value of 0.49$\pm$0.12 [range: 0.25-0.74]. The hospital mortality was 10.3% [6 patients], and causes of deaths were right heart failure due to sustained right ventricular hypertension[4] and right ventricular outflow tract obstruction, intractablesuraventricular tachyarrhythmia[1], hypoxia[1] due to residual right to left shunt across the atrial septal defect in patient associated with Ebstein`s anomaly. All infants were doing well at follow-up from 1 to 101 months[20.6 months /patient, 1, 072 patient-month] Serial postoperative echocardiograms revealed no residual ventricular septal defects and estimated RVOT gradients between 0 and 40 mmHg except 3 cases [50, 50, 60 mmHg]. There were no late deaths and late ventricular arrhythmias or congestive heart failure. Redo operations were done in 2 cases because of residual right ventricular outflow tract obstruction. This experience with infants with tetralogy of Fallot suggests that, if mortality is tolerable, eletive repair of tetralogy of Fallot could be reasonably undertaken during the first year of life, and even better results could be anticipated along with improvement of methods of myocardial protection and postoperative care.

• The Korean Journal of Physiology
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• v.2 no.2
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• pp.11-20
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• 1968

Maximal oxygen uptake was measured in thirty-three secondary school girls by means of the treadmill test. Eighteen middle school girls aged 14.0 (range: $13.0{\sim}15.9$) years and fifteen high school girls aged 16.9 (range: $16.0{\sim}18.0$) years served as subjects. Maximal treadmill run lasted for 2 minutes and 20 seconds and the expired air was collected in a Douglas bag through a J-valve during the last one minute period. In general, absolute values of various measurements in the high school girls were greater than those of the middle school girls. When values were expressed on the body weight or lean body weight basis, however, work capacity of middle school girls was superior to that of the high school girls. The detailed results are as follows: 1. In middle school girls maximal oxygen uptake was 1.78 l/min., 47.4 ml/kg body weight, 12.3 ml/cm body height, and 61.7ml/kg lean body mass. In high school girls maximal oxygen uptake was 1.93 l/min., 39.7ml/kg body weight, 12.3 ml/cm body height, and 51.2 ml/kg LBM. Although the absolute value of maximal oxygen uptake was greater in high school girls than in middle school girls, values expressed on the body weight basis showed the reverse trend, namely, values of the middle school girls was greater than those of the high school girls. 2. The ratio of maximal to resting oxygen uptake was 8.8 in the middle school girls and was 10.2 in the high school girls. 3. Maximal pulmonary ventilation in the middle school girls was 55.3 l/min. and 66.1 l/min. in the high school girls. The ratio of maximal to resting pulmonary ventilation was 10.2 in the middle school girls and 10.1 in the high school girls. 4. The correlation between body weight and maximal oxygen uptake was relatively high, namely, r=0.79 both in middle and high school girls. The correlation coefficient between body weight and maximal pulmonary ventilation was a little less that of between maximal oxygen uptake and showed a value of r=0.60 both in middle and high school girls. The lean body mass was a poor reference of maximal oxygen uptake or maximal pulmonary ventilation as compared to body weight. The correlation between maximal oxygen uptake and maximal pulmonary ventilation was high and the coefficient of correlation in middle school girls was 0.927 and in high school girls it was 0.856. 5. Maximal ventilation equivalent was 30.9 liters in middle school girls and 33.9 liters in high school girls. This indicated that no hyperventilation was induced during the maximal of oxygen uptake exercise period as related to the maximal oxygen uptake. 6. Heart rate reached to the peak value within 1.5 minutes after beginning of maximal oxygen uptake run and remained at the same peak plateau level throughout the entire running period. Heart rate decreased steeply on cessation of running and subsided slowly thereafter. The maximal heart rate was 184 beat/min. in middle school girls and 189 beat/min. in high school girls. 7. Maximal oxygen pulse was 9.4 in middle school girls and 9.9 ml/beat in high school girls.

• Journal of Drive and Control
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• v.12 no.4
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• pp.60-70
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• 2015

A front-end loader (FEL) mounted on an agricultural tractor is one of the most commonly used implements for farm work. However, when the tractor carries material using the bucket attached to the FEL on a sloping ground, the materials can spill or roll back over the operator due to the tilted body, thereby requiring the bucket surface to remain level at a constant value regardless of varying slopes. In this study, an active system for controlling the angle of the FEL bucket on a tractor based on the real-time measurement of ground slopes was developed to enable the bucket to constantly remain level. A FEL simulator operated based on an electro hydraulic proportional valve (EHPV) was constructed in the laboratory to develop a proportional-integral-derivative (PID) controller forming a virtual electronic control unit (ECU) on the computer, which could automatically adjust the bucket angles depending on varying input angles while sending SAE-J1939 associated messages via CAN BUS to the EHPV. The different parameter values for the PID controller due to the gravity effect of the bucket were determined using a manual PID tuning method while assuming that the tractor travels on either an ascending slope or a descending slope. The developed PID control-based self-leveling system showed a mean of steady-state errors of within $1^{\circ}$ and a mean of delayed times of ~ 0.8s when the step input of $+20^{\circ}$ was given, implying that the developed system and control algorithm would be effective in maintaining the bucket angle at a certain value. Future studies include the improvement of the control algorithm to reduce such a time delay as well as the application of the developed algorithm to the FEL mounted on a tractor tested at a testing ground.

• Journal of Chest Surgery
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• v.44 no.2
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• pp.108-114
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• 2011

Background: Homograft cardiac valves and valved-conduits have been available in our institute since 1992. We sought to determine the long-term outcome after right ventricular outflow tract (RVOT) reconstruction using homografts, and risk factors for reoperation were analyzed. Materials and Methods: We retrospectively reviewed 112 patients who had undergone repair using 116 homografts between 1992 and 2008. Median age and body weight at operation were 31.2 months and 12.2 kg, respectively. The diagnoses were pulmonary atresia or stenosis with ventricular septal defect (n=93), congenital aortic valve diseases (n=15), and truncus arteriosus (N=8). Mean follow-up duration was $79.2{\pm}14.8$ months. Results: There were 10 early and 4 late deaths. Overall survival rate was 89.6%, 88.7%, 86.1% at postoperative 1 year, 5 years and 10 years, respectively. Body weight at operation, cardiopulmonary bypass (CPB) time and aortic cross-clamping (ACC) time were identified as risk factors for death. Forty-three reoperations were performed in thirty-nine patients. Freedom from reoperation was 97.0%, 77.8%, 35.0% at postoperative 1 year, 5 years and 10 years respectively. Small-sized graft was identified as a risk factor for reoperation. Conclusion: Although long-term survival after RVOT reconstruction with homografts was excellent, freedom from reoperation was unsatisfactory, especially in patients who had small grafts upon initial repair. Thus, alternative surgical strategies not using small grafts may need to be considered in this subset.

• Journal of Chest Surgery
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• v.35 no.11
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• pp.785-791
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• 2002

The results of reoperative valve replacement can be improved if appropriate analysis for the risk of reoperation was achieved. The purpose of our study was to analyze the results of reoperations for failure of bioprosthesis, and to define the risk factors in high-risk populations for reoperative procedures. Material and Method The series of 46 consecutive patients who had undergone first reoperative replacement for failed bioprosthesis between 1993 and 2001 were reviewed retrospectively. Mean age was 42 $\pm$ 12 years, mean body surface area was 1.52 $\pm$0.15 $m^2$. The reoperative procedure comprised of 36 MVR, 8 DVR, and 2 AVR. The first operation comprised of 2 DVR, 1 AVR, and 43 MVR. Factors which were choose to assess a predictor of results in reoperative valve replacement were sex, old age(＞60 years), early age at first operation(＜30 years), long interval between first and redo operation(.15years), poor NYHA functional class(＞3), LV dysfunction(LVEF＜45%), long operation time(＞8hours), endocarditis, combined procedures, and renal insufficiency, Result : Overall mortality was 4.3%(2 cases). The risk factors that influenced postoperative complications and unexpected postoperative results were lower ejection fraction(p＝0.012), older age(p＝0.045), endocarditis(p＝0.023), long operation time above 8 hours(p＝0.027). There was no statistically significant factor influencing hospital mortality. Conclusion : No factor influenced the mortality. Better results could be achieved if reoferation was performed carefully in poor left ventricular function, old aged patient, and with endocarditis. Effort to shorten the operation time would be helpful on postoperative results.

• International Journal of Automotive Technology
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• v.3 no.1
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• pp.27-32
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• 2002

Semi-active suspension systems are greatly expected to be in the mainstream of future controlled suspensions fur passenger cars. In this study, a continuous variable damper for a passenger car suspension is developed. It is controlled actively and exhibits high performance with light weight, low cost, and low energy consumption. To get fast response of the damper, reverse damping mechanism is adapted, and to get small pressure change rate after blow-off, a pilot controlled proportional valve is designed and analyzed. The reverse continuous variable damper is designed as a HS-SH damper which offers good body control with reduced transferred input force from tire, compared with any other type of suspension system. The damper structure is designed, so that rebound and compression damping force can be tuned independently, of which variable valve is placed externally. The rate of pressure change with respect to the flow rate after blow-offbecomes smooth when the fixed orifice size increases. Damping forces are measured with the change of the solenoid current at the different piston velocities to confirm the maximum hysteresis of 20N, linearity, and variance of damping farce. The damping farce variance is wide and continuous, and is controlled by the spoof opening, of which scheme is usually adapted in proportional valves. The reverse continuous variable damper developed in this study is expected to be utilized in the semi-active suspension systems in passenger cars after its performance and simplicity of the design is confirmed through real car test.

• Clinical and Experimental Pediatrics
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• v.62 no.6
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• pp.240-243
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• 2019

Purpose: Coronary arterial lesion assessment in children can be difficult, depending on the coronary dominance pattern. Although it is easier to determine coronary dominance with echocardiography in children than in adults, it is still difficult. This study aimed to examine the coronary dominance pattern according to the objective coronary artery (CA) indices. Methods: The CA diameter, aortic valve annulus, and abdominal aorta of 69 children without any cardiovascular disease were measured with cross-sectional echocardiography at Chungnam National University Hospital. To evaluate the coronary dominance pattern, echocardiography was primarily used; additionally, coronary computed tomographic angiography or coronary angiography (CAG). Coronary dominance was determined according to the status of the CA that gives rise to the posterior descending artery. Results: The mean age was $4.02{\pm}2.78years$, and the mean body surface area (BSA) was $0.70{\pm}0.22m^2$. Right dominance was present in 78% and left in 22% of the subjects. In those with left dominance, the CA to aortic valve annulus diameter ratio was $0.125{\pm}0.021$ in the right coronary artery (RCA) and $0.255{\pm}0.032$ in the left coronary artery (LCA). In those with right dominance, the corresponding ratio was $0.168{\pm}0.028$ in the RCA and $0.216{\pm}0.030$ in the LCA (P<0.05). Significant differences were also found in the diametric ratios of the CA to BSA and abdominal aorta (P<0.05). Conclusion: The CA indices showed significant difference according to the coronary dominance pattern in early childhood. It is possible to indirectly determine the coronary dominance pattern with the CA indices in children using echocardiography. The accuracy of coronary artery lesion diagnosis can be improved by taking coronary dominance into account.