• Journal of Korean Society of Transportation
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• v.20 no.3
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• pp.115-128
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• 2002

Dislike the tangent sections, the horizontal curve sections of roads should be designed, considering several factors : one of such factors is widening. In other words, since widening results from that when a vehicle runs on the horizontal curve sections, the rear wheels of the vehicle run not along with tracks of the front wheels but out of that, such offtracking should be exactly investigated and reflected in design of the curve sections. Especially in the case of industrial roads which semi-trailers and large trucks run frequently or arterial roads with small curve radiuses in mountainous regions. serious offtracking Phenomenons result in increasing the risk of accidents. decreasing the capacities and jeopardizing pedestrians' safety on the curve sections. For the offtracking, widening amounts of roads has been determined under the traditional presumption that vehicles run at a low speed and there is no superelevation. In fact, however, since the vehicles run at a high speed as well as at a low speed and the superelevation is installed on the horizontal curve sections in the structural aspect of roads, the existing standards for installing widening have a limitation to reflect exactly actual Phenomenons. In particular, for articulated wheel axles of a tractor and a trailer and long articulated vehicles, not only the offtracking degree is very high but also the interpretation shows different aspects from one of single axles. Comparing and reviewing the results of Korean and foreign studies related to the trailer offtracking model theory and the standards for installing widening, this study developed a realistic dynamic offtracking model which considers geometric structures of roads and speeds of vehicles, suggested how to measure widening with this model and examined applicability of the model. The findings of this study are as follows ; First. a dynamic offtracking model. which considers dynamic movements of a tractor and a trailer and the superelevation, was developed. Second, a new method to measure widening with the developed dynamic offtracking model was developed and a method to measure widening with swept path width was suggested as well. Finally, validity of the current standards for installing widening was examined by determining actual offtracking and widening amounts with the developed model and the applicability was investigated through the case studies. Compared with the existing offtracking models, the dynamic offtracking model developed in this study can reflect practically vehicle speed. dimension and geometric structural aspects of roads. In conclusion, the meaning of this study is that it reviews validity of the current standards for installing widening and provides a base to establish such standards by suggesting new methods to measure the widening with this dynamic offtracking model.

• Journal of Chest Surgery
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• v.39 no.8 s.265
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• pp.619-625
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• 2006

Background: Peripheral arterial disease is frequently accompanied with systemic arteriosclerosis and more than half of the cause of deaths is due to the development of coronary arterial disease. Moreover, it is known that the most frequent cause of death after a bypass surgery of chronic arterial obstruction is heart related complications. Especially in patients with atherosclerotic arterial obstruction in the lower extremities who had no history of heart disease or had no presenting symptoms of ischemic heart disease showed a high rate of postoperative mortality and for this reason we suggest preoperative evaluation in these patients to evaluate whether or not coronary arterial disease is accompanied. Material and Method: Since Feb. 2001 to Oct. 2004, we analyzed 52 patients who were operated on for atherosclerotic arterial obstruction in the lower extremities, with the exception of patients with a past history of heart disease or symptoms of ischemic heart disease. They underwent on the same day a coronary and femoral angiography for evaluation of accompanying coronary arterial disease. Of among these patients, we compared those who received bypass surgery of the arteries of the peripheral extremities alone to those who underwent combined coronary artery bypass surgery. Result: 63% of the reported cases of atherosclerotic arterial obstruction in the lower extremities were accompanied with coronary arterial disease. Old age, hypertension, diabetes mellitus, smoking, and hypercholesterolemia are known risk factors for arteriosclerosis and of these, only old age and hypertension had statistically significance in patients with severe atherosclerotic arterial obstruction in the lower extremities accompanied with coronary arterial disease. Diabetes, smoking, and hypercholesterolemia showed no statistical significance in this group. With the increase in severity of the range and the degree of atherosclerotic arterial obstruction, coronary arterial disease is frequently accompanied and its severity also increased. Patients who received both peripheral artery and coronary artery bypass surgery showed no difference in the period of hospitalization and ICU stay period compared with patients who received bypass surgery of the arteries of the lower extremities alone. Conclusion: Patients with atherosclerotic arterial obstruction in the lower extremities without symptoms of ischem to evaluate coronary arterial disease for active treatment, especially in the patients with old age, hypertension and high AVD scores.

• Journal of Chest Surgery
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• v.31 no.8
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• pp.739-748
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• 1998

Background: It has been well documented that transient occlusion of the coronary artery causes myocardial ischemia and finally cell death when ischemia is sustained for more than 20 minutes. Extensive studies have revealed that ischemic myocardium cannot recover without reperfusion by adequate restoration of blood flow, however, reperfusion can cause long-lasting cardiac dysfunction and aggravation of structural damage. The author therefore attempted to examine the effect of postischemic reperfusion on myocardial ultrastructure and to determine the rationales for recanalization therapy to salvage ischemic myocardium. Materials and methods: Young Holstein-Friesian cows(130∼140 Kg body weight; n=40) of both sexes, maintained with nutritionally balanced diet and under constant conditions, were used. The left anterior descending coronary artery(LAD) was occluded by ligation with 4-0 silk snare for 20 minutes and recanalized by release of the ligation under continuous intravenous drip anesthesia with sodium pentobarbital(0.15 mg/Kg/min). Drill biopsies of the risk area (antero-lateral wall) were performed at just on reperfusion(5 minutes), 1-, 2-, 3-, 6-, 12-hours after recanalization, and at 1-hour assist(only with mechanical respiration and fluid replacement) after 12-hour recanalization. The materials were subdivided into subepicardial and subendocardial tissues. Tissue samples were examined with a transmission electron microscope (Philips EM 300) at the accelerating voltage of 60 KeV. Results: After a 20-minute ligation of the LAD, myocytes showed slight to moderate degree of ultrastructural changes including subsarcolemmal bleb formation, loss of nuclear matrix, clumping of chromatin and margination, mitochondrial destruction, and contracture of sarcomeres. However, microvascular structures were relatively well preserved. After 1-hour reperfusion, nuclear and mitochondrial matrices reappeared and intravascular plugging by polymorphonuclear leukocytes or platelets was observed. However, nucleoli and intramitochondrial granules reappeared within 3 hours of reperfusion and a large number of myocytes were recovered progressively within 6 hours of reperfusion. Recovery was apparent in the subepicardial myocytes and there were no distinct changes in the ultrastructure except narrowed lumen of the microvessels in the later period of reperfusion. Conclusions: It is likely that the ischemic myocardium could not be salvaged without adequate restoration of coronary flow and that the microvasculature is more resistant to reversible period of ischemia than subendocardium and subepicardium. Therefore, thrombolysis and/or angioplasty may be a rational method of therapy for coronarogenic myocardial ischemia. However, it may take a relatively longer period of time to recover from ischemic insult and reperfusion injury should be considered.

• Journal of Chest Surgery
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• v.40 no.11
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• pp.727-732
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• 2007

Background: The reciptents of aortic valve replacement or a Bentall operation usually display various degrees of mitral regurgitation. When deciding whether or not to correct the mitral regurgitation, one must consider its severity, underlying causes and operative risk. Recently, the operation method for correcting the concomitant mitral regurgitation has been done through aortic root to reduce the operation time and the cardiac trauma. We report our experiences that transaortic mitral valve commissuroplasty done with aortic valve replacement or a Bentall operation has been a simple, less invasive, effective method in the operative management of mitral valve regurgitation without significant organic changes. Material and Method: Between June 2002 and June 2005, twenty patients under-went mitral valve commissuroplasty via the aortic root with aortic valve replacement (n=14) or a Bentall operation (n=7). The mitral valve regurgitation of the patients didn't exceed a moderate (grade 2) degree and there was no significant organic disease. The preoperative diagnosis of MR was established by TTE and intraoperative TEE, and the patients were followed postoperatively by TTE. The operative technique was a simple anterolateral commissuroplasty of the mitral valve with a single mattress suture via the transaortic annular approach after excision of the aortic valve leaflets. Result: The mean patient age was 56.2 years and 65% (n=13) were male. The preoperative MR was mild (grade 1) in 9 (45%), mild to moderate in 8 (40%), and moderate (grade 2) in 3 (15%) patients. There were no operative mortalities. The MR improved in all patients (p=0.002) and the left ventricular ejection fraction (LV EF) improved in 14 (70%) patients (p=0.005). The mean cross-clamp time for the patients who under- went aortic valve replacement with transaortic mitral repair was $62.1{\pm}13.9 min$ and this was $137.5{\pm}7.2 min$ for the patients who underwent a Bentall operation with transaortic mitral repair. Conclusion: For selected patients without significant mitral organic disease, transaortic mitral valve commissuroplasty combined with aortic valve replacement or a Bentall operation may be a feasible, effective method without adding significant aortic cross clamping time and more cardiotomy.

• Korean Journal of Psychosomatic Medicine
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• v.7 no.1
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• pp.61-71
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• 1999

Objective : The purpose of this study was to assess the relationship between the premenstrual changes and stress perception in women with premenstrual changes($PMC^+$)(n=32) and those without premenstrual changes($PMC^-$)(n=62) by using prospective method. Method : The women who were older than 30 years of age and healthy were asked to complete a daily rating form based on DSM-IV diagnostic criteria for one menstrual cycle to assess the changes of psychological and physical symptoms across the menstrual cycle. They also completed 5-point likert scale to assess the perception of stress. Percent changes method was used to assess changes between follicular phase and luteal phase. Results : 1) No significant differences were found in demographic factors(age, education, marriage, employment) and risk factors(onset ages of menarche, regularities of premenstrual changes, duration of menstruation, cycle length, amount of menstruation, dysmenorrhea) between women with and without premenstrual changes. 2) There was a significant difference in mean luteal phase stress score between women with($1.92\pm0.63$) and without premenstrual changes($1.51\pm0.42$)(p<0.05). However no difference was found in mean follicular phase stress score between two groups($PMC^+$ : $1.67\pm0.43$, $PMC^-$ : $1.33\pm0.39$). 3) We divided women having premenstrual changes into two groups, higher stress group(stress score > 1.75(median)) and the lower stress group(stress score <1.75(median)). The higher stress group reported more luteal psychological symptoms than did the lower stress group(df=1, F=13.362, p<0.001). However, the groups did not differ in physical symptoms. Conclusion : In women with premenstrual changes, luteal stress score was higher than follicular stress score and this result suggested tha the perception of stress was related to psychological symptoms but not physical symptoms. These findings suggested that premenstrual change is associated with the stress level, and that it is important to manage the stress which is focused on the management of psychological symptom in the treamtment of prementrual syndrome.

• Management & Information Systems Review
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• v.29 no.2
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• pp.1-25
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• 2010

This study attempted to empirically test the determinants of stock returns in Korean stock market applying multi-factor model proposed by Haugen and Baker(1996). Regression models were developed using 16 variables related to liquidity, risk, historical price, price level, and profitability as independent variables and 690 stock monthly returns as dependent variable. For the statistical analysis, the data were collected from the Kis Value database and the tests of forecasting power in this study minimized various possible bias discussed in the literature as possible. The statistical results indicated that: 1) Liquidity, one-month excess return, three-month excess return, PER, ROE, and volatility of total return affect stock returns simultaneously. 2) Liquidity, one-month excess return, three-month excess return, six-month excess return, PSR, PBR, ROE, and EPS have an antecedent influence on stock returns. Meanwhile, realized returns of decile portfolios increase in proportion to predicted returns. This results supported previous study by Haugen and Baker(1996) and indicated that firm-characteristic model can better predict stock returns than CAPM. 3) The firm-characteristic model has better predictive power than Fama-French three-factor model, which indicates that a portfolio constructed based on this model can achieve excess return. This study found that expected return factor models are accurate, which is consistent with other countries' results. There exists a surprising degree of commonality in the factors that are most important in determining the expected returns among different stocks.

• Tuberculosis and Respiratory Diseases
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• v.50 no.6
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• pp.693-703
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• 2001

Background : Smoking is the most important and consistent determinant of the development and progression of COPD(Ed Note : Define COPD). The fact that cigarette smokers develop a different type of COPD, chronic bronchitis and emphysema, with different clinical and pathological aspects, suggests that the development of COPD has a relationship with other smoking-associated factors beyond just a simple smoking history. The aim of this was to analyze the smoking habits and history of patients with COPD and to evaluate the development of different types of COPD according to patient's smoking habits. Method : To evaluate the differences in the smoking patterns of patients with chronic bronchitis and emphysema, a pulmonary function test was conducted, and the smoking history and patterns was obtained through a smoking history questionnaire by a direct personal interview from 333 male cigarette smokers diagnosed with COPD, in the Yeungnam university medical center(190 patients diagnosed with chronic bronchitis, 143 patients diagnosed with emphysema). Result : The patients with emphysema smoked earlier and had a higher smoking history(ie, more packyears, more total amounts of smoked cigarette, and more deep inhalation and longer duration of plain cigarette exposure) than those with chronic bronchitis. The depth of inhalation was also significantly higher in the emphysema patients after taking into account age, cumulative cigarette consumption and the type of cigarette smoked. Conclusion : Emphysema was more associated with the increasing degree of inhalation as assessed by the depth of inhalation. A high alveolar smoke exposure may be a significant risk factor for the development of emphysema.

• Journal of Gastric Cancer
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• v.6 no.2
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• pp.76-83
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• 2006

Purpose: Endoscopic incision and submucosal dissection (EISD) is a technique that is being implemented for the resection of gastric adenomas and early gastric cancer (EGC). Since EISD requires a high degree of skill and experience, and due to its association with a moderate risk of gastrointestinal bleeding, its use has been limited. The objective of this study is to investigate the clinical benefits of EISD based upon clinical data on the EISD procedure. Materials and Methods: This study was conducted at Soonchunhyang University Hospital and it included 179 gastric adenoma and early gastric carcinoma lesions from 164 patients who had undergone an EISD from February 2003 to May 2005. Results: Among the total of 179 lesions, the distributions of EGC and adenomas were 70.3% (126/179) and 23.4% (42/179) respectively. The sizes of lesions were divided into 10 mm or less, $11{\sim}20\;mm,\;21{\sim}30\;mm$ and greater than 31 mm and each rates are 10.0% (18/179), 46.3% (83/179), 30% (50/179) and 15.0% (28/179). Among 120 cases which could be measured depth of lesion in according to pathologic findings, m1 (0.8%, 1/120), m2 (38.3%, 46/120), m3 (25%, 57/120), sm1 (11.7%, 14/120), sm2 (1.6%, 2/120) were diagnosed as early stages of gastric cancer. The complete resection rate was 85.2% (150/176) and en-bloc resection rate was 96.0% (169/176). Complications as such as perforation and bleeding developed in 4.4%(8/179) and 21.2% (38/179), respectively. Conclusion: EISD is an effective in the endoscopic treatment for gastric adenoma and early gastric cancers. However, further evaluation of this method and long-term follow-up will be necessary for an evaluation of the recurrence rate after resection of a tumor.

• Journal of Bio-Environment Control
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• v.24 no.4
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• pp.301-307
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• 2015

High quality transplants are critical for success in crop production. Increasing numbers of growers purchase their transplants from specialized transplant producers instead of growing their own transplants. A drawback of purchasing transplants is the risk of deterioration to transplants during transportation from transplant producers to the growers. This study evaluates the influence of temperature on the quality of grafted tomatoes transplants (Solanum lycopersicum cv. Super Doterang), in order to propose optimum temperature condition for the transportation of grafted tomato transplants. Grafted tomato transplants with visible flower trusses were exposed to different air temperature ($10^{\circ}C$, $25^{\circ}C$, or $40^{\circ}C$) for 2, 4, or 6 hours. After treatment, the NDVI (Normalized Difference Vegetation Index) values of tomato transplants treated at 25 and $40^{\circ}C$ were lower than that at $10^{\circ}C$. The root fresh weight was lowest at $40^{\circ}C$. After transplanting, the transplants that were exposed to the air temperature of $40^{\circ}C$ exhibited chlorosis and blight on lower leaves. The degree of damage on leaves was severer as the high temperature exposure time was longer. The temperature conditions during the transportation also influenced the growth, flowering and fruit set of tomatoes after transplanting. The fruit number and weight of first truss was lowest at $40^{\circ}C$ for 6 hours. Accordingly, it is recommended that the temperature during the transportation should be controlled and kept at the range from 10 to $25^{\circ}C$ even though the period is short (within as six hours) in order to maintain the quality of transplants.

• Horticultural Science & Technology
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• v.32 no.4
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• pp.517-524
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• 2014

As an assessment of substantial equivalence and environmental risks of branchless chrysanthemum GM lines (LeLS69, LeLS76, LeLS80) developed in Korea, we investigated their degree of branchlessness and developmental characteristics including growth and flowering, as well as the stability of populations of insect pests and soil microbes. The GM lines were compared with a control variety, 'Jinba'. LeLS80 showed the highest level of branchlessness among the three GM lines, whereas abnormal axillary buds developed in lines LeLS76 and LeLS69. There were no significant differences between the growth characteristics of 'Jinba' and the GM lines. The branchlessness LeLS80 was increased during the summer season, suggesting that it is a useful germplasm for developing elite branchless cultivars. These GM lines showed no significant differences in the occurrence of five insect pests including aphids, mites, leaf miners, thrips, and whiteflies. Similarly, for soil microbes including bacteria and actinomycetes, there were no significant differences between 'Jinba' and the GM lines. However, there was a higher occurrence of fungi in the GM lines compared to 'Jinba'. Our findings suggest that 'Jinba' and the GM lines are substantially equivalent, although further monitoring studies are needed to confirm this.