• Journal of Forest and Environmental Science
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• v.13 no.1
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• pp.51-56
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• 1997

Developmental characteristics and reproductive ability of Caloglyphus sp. were examined under the constant temperature conditions. This mites has five stages ; egg, larva, protonymph, deutonymph and adult. All active instars preyed on larvae of pine gall midge, Thecodiplosis japonensis Uchida et Inouye. The developmental period from the egg to the adult decreased with temperature increase at a range between $15^{\circ}C$ and $30^{\circ}C$. The threshold of temperature and the thermal constant for the development from the egg to the adult were $8.2^{\circ}C$ and 122.0 day-degrees, respectively. At $25^{\circ}C$, survival rate from egg to deutonymph was estimated as 66.4%, and longevity of the adult was 12.3 days for male and 10.0 days for female. After a preoviposition period of 1 and 2 days female laid an average of 360.6 eggs each, almost all during the first half of their life time. The value of the net reproduction(Ro), the mean length of a generation(T) and the intrinsic rate of natural increase($r_m$) were calculated as 101.1, 9.3 days and 0.494 per female per day, respectively.

• Journal of Chest Surgery
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• v.44 no.5
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• pp.332-337
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• 2011

Background: The optimal timing of surgery for infective endocarditis complicated by embolic stroke is unclear. We compared early versus delayed surgery in these patients. Materials and Methods: Between 1992 and 2007, 56 consecutive patients underwent open cardiac surgery for the treatment of infective endocarditis complicated by acute septic embolic stroke, 34 within 2 weeks (early group) and 22 more than 2 weeks (delayed group) after the onset of stroke. Results: The mean age at time of surgery was $45.7{\pm}14.8$ years. Stroke was ischemic in 42 patients and hemorrhagic in 14. Patients in the early group were more likely to have highly mobile, large (>1 cm in diameter) vegetation and less likely to have hemorrhagic infarction than those in the delayed group. There were two (3.7%) intraoperative deaths, both in the early group and attributed to neurologic aggravation. Among the 54 survivors, 4 (7.1%), that is, 2 in each group, showed neurologic aggravation. During a median follow-up of 61.7 months (range, 0.4~170.4 months), there were 5 late deaths. Overall 5-year neurologic aggravation-free survival rates were $79.1{\pm}7.0%$ in the early group and $90.9{\pm}6.1%$ in the delayed group (p=0.113). Conclusion: Outcomes of early operation for infective endocarditis in stroke patients were similar to those of the conventional approach. Early surgical intervention may be preferable for patients at high risk of life-threatening septic embolism.

• Parasites, Hosts and Diseases
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• v.29 no.3
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• pp.267-278
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• 1991

The natural killer (NK) cell activity of splenocytes and recycling capacity of NK cells were observed by combining the $^{51}Cr-release$ cytotoxicity assay and single cell cytotoxicity assay against YAC-1. The ICR mice were infected intranasally with Naegleria fewleri, that is a pathogenic free-living amoeba. The mice infected with $1{\times}10^5$ trophosoites showed mortality rate of 76.7% and mean survival time of 12. 9 days. The cytotoxic activity of NK cells in infected mice was significantly higher than that of non-infected mice during the period between 12 hours and day 3 after infection, and highest on day 1. The target-binding capacity of NK cells in infected mice was not different from that of non-infected ones. Maximal killing potential and maximal recycling capacity were remarkably increased in infected mice as compared with the control. The results obtained in this observation indicated that elevated NK cell activity in mice infected with N. fowieri was not due to target-binding capacity of NK cells but due to the increased activity of NK cells and increased recycling capacity of individual NK cells.

• Journal of the Korean Society of Marine Environment & Safety
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• v.27 no.5
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• pp.574-583
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• 2021

Predicting shipping markets is an important issue. Such predictions form the basis for decisions on investment methods, fleet formation methods, freight rates, etc., which greatly affect the profits and survival of a company. To this end, in this study, we propose a shipping freight rate prediction model for container ships using gated recurrent units (GRUs) and long short-term memory structure. The target of our freight rate prediction is the China Container Freight Index (CCFI), and CCFI data from March 2003 to May 2020 were used for training. The CCFI after June 2020 was first predicted according to each model and then compared and analyzed with the actual CCFI. For the experimental model, a total of six models were designed according to the hyperparameter settings. Additionally, the ARIMA model was included in the experiment for performance comparison with the traditional analysis method. The optimal model was selected based on two evaluation methods. The first evaluation method selects the model with the smallest average value of the root mean square error (RMSE) obtained by repeating each model 10 times. The second method selects the model with the lowest RMSE in all experiments. The experimental results revealed not only the improved accuracy of the deep learning model compared to the traditional time series prediction model, ARIMA, but also the contribution in enhancing the risk management ability of freight fluctuations through deep learning models. On the contrary, in the event of sudden changes in freight owing to the effects of external factors such as the Covid-19 pandemic, the accuracy of the forecasting model reduced. The GRU1 model recorded the lowest RMSE (69.55, 49.35) in both evaluation methods, and it was selected as the optimal model.

• (The)Study of the Eastern Classic
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• no.41
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• pp.385-406
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• 2010

Lee Byeong-hun was introduced to Hanjuhak when he was taught by Myeonwoo Gwak Jong-seok. It is assumed that Hanjuhak circles had a certain influence on formation of his ideas in that they had liberal tendency at that time. Lee Byeong-hun accepted Geummungyonghak developed by Gang Yu-wee of China and participated in Confucian Science Movement while excluding Confucianism. After he accepted western civilization and the ideas of Gang Yu-wee, no traces of Hanjuhak was found in his writing, but it is assumed that Hanjuhak might work as a nutritious element for his ideas. He thought that religious nature of Confucianism could be revived only when he left Neo-confucianism which changed Confucianism into a philosophy by insisting reason instead of God. So, he respected Confucius as a religious founder and left such concepts as reason and respect which were considered important in Neo-confucianism and valued disposition and faith in "Jungyong", a doctrine of the Mean. He considered Confucianism as religious and joined in religious practices such as praying and reciting scriptures. He insisted that filial piety indicates a filial son of the Heaven when interpreting the following passage: Shun (Chinese leader) is a filial duty, which is assumed that he was influenced by Christianity. He respected Confucius as the only religious founder and God as the God to make Confucianism a religion. It is believed that he considered only Confucius as a founder instead of traditional Confucian sages as religion such as Buddhism and Christianity has one founder. God he thought is related with the God in Christianity and furthermore accepted reincarnation of Buddhism which is contrary to Confucian ideas. According to "Gyeongseol" by Lee Byeong-hun, it was believed that he was engaged in religion based on a faith that Confucianism is a religion rather than he pursued Confucianism as a religion to find out a way of its survival.

• Korean Journal of Radiology
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• v.21 no.6
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• pp.695-706
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• 2020

Objective: To investigate the technical and clinical efficacy of the percutaneous insertion of a biliary metallic stent, and to identify the factors associated with biliary stent dysfunction in patients with malignant duodenobiliary obstruction. Materials and Methods: The medical records of 70 patients (39 men and 31 women; mean age, 63 years; range, 38-90 years) who were treated for malignant duodenobiliary obstruction at our institution between April 2007 and December 2018, were retrospectively reviewed. Variables found significant by univariate log-rank analysis (p < 0.2) were considered as suitable candidates for a multiple Cox's proportional hazard model. Results: The biliary stents were successfully placed in all 70 study patients. Biliary stent insertion with subsequent duodenal stent insertion was performed in 33 patients and duodenal stent insertion with subsequent biliary stent insertion was performed in the other 37 study subjects. The median patient survival and stent patency time were 107 days (95% confidence interval [CI], 78-135 days) and 270 days (95% CI, 95-444 days), respectively. Biliary stent dysfunction was observed in 24 (34.3%) cases. Multiple Cox's proportional hazard analysis revealed that the location of the distal biliary stent was the only independent factor affecting biliary stent patency (hazard ratio, 3.771; 95% CI, 1.157-12.283). The median biliary stent patency was significantly longer in patients in whom the distal end of the biliary stent was beyond the distal end of the duodenal stent (median, 327 days; 95% CI, 249-450 days), rather than within the duodenal stent (median, 170 days; 95% CI, 115-225 days). Conclusion: The percutaneous insertion of the biliary metallic stent appears to be a technically feasible, safe, and effective method of treating malignant duodenobiliary obstruction. In addition, a biliary stent system with a distal end located beyond the distal end of the duodenal stent will contribute towards longer stent patency in these patients.

• Journal of Chest Surgery
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• v.43 no.6
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• pp.627-634
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• 2010

Background: The durability of the tissue valve is important in choice between a mechanical valve and a tissue valve in cardiac surgery. We studied the mid-term results of tissue valve in the aortic position. Material and Method: The subjects were 380 patients who had undergone aortic prosthesis replacement between May 1990 and March 2009. We retrospectively analyzed hospital and outpatient records: the mean age was $69{\pm}9$ years; the male to female ratio was 227 : 162; and the mean follow-up duration was $46.7{\pm}40.8$ months (range 0~196 months). Result: 389 surgical cases in total had been taken with 380 patients. Early death occurred in 15 patients (3.9%). Overall survival rate at 1, 5 and 10 years were 92.3%, 78.1% and 54.2% respectively. Freedom from reoperation at 1, 5 and 10 years were 98.4%, 97.1% and 91.7% respectively. Freedom from structural valvular deterioration at 1, 5 and 10 years were 96.1%, 92.3% and 88.0% respectively. In the multivariate analysis of preoperative risk factors, young age (p<0.001) was significant risk factor for reoperation. High peak velocity in the postoperative period (p=0.034) and young age (p=0.029) were significant risk factors for structural valvular deterioration. Old age (p=0.001), long bypass time (p=0.035), concomitant coronary artery bypass graft surgery (p=0.003) and preoperative low left ventricular ejection fraction (p=0.003) were significant factors for early mortality. Preoperative estimated glomerular filtration rate (< 60 mL/min) (p=0.025) and persistent left ventricular hypertrophy (p=0.032) were the risk factors for late mortality. Conclusion: This study showed that the freedom from reoperation and the freedom from structural valvular deterioration in aortic tissue valve replacement were acceptable. It will be necessary to conduct further studies with long-term follow-up and more patients.

• Tuberculosis and Respiratory Diseases
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• v.40 no.3
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• pp.283-291
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• 1993

Background: Long-term low flow oxygen therapy not only increases survival, but also improves the quality of life in patients with chronic obstructive pulmonary disease (COPD) with chronic hypoxemia. For the assessment and improvement of the status of home oxygen therapy, we analyzed clinical experience of 26 patients who have been administered low flow oxygen at home. Method: Twenty-six patients (18 men and 8 women) who have been received long-term oxygen therapy (LTOT) at home were examined. We reviewed physical characteristics, clinical history, pulmonary function test, ECG, arterial blood gas analysis, hemoglobin and hematocrit, types of oxygen devices, inhalation time per day, concentration of administered $O_2$, duration of $O_2$ therapy, and problems in the home oxygen therapy. Results: The underlying diseases of patients were COPD 14 cases, far advanced old pulmonary tuberculosis 9 cases, bronchiectasis 2 cases, and idiopathic pulmonary fibrosis 1 case. The reasons for LTOT at home were noted for cor pulmonale 21 cases, for dyspnea on exertion and severe ventilatory impairment 4 cases, and for oxygen desaturation during sleep 1 case. The mean values of aterial blood gas analysis before home oxygen therapy were $PaO_2$ 57.7 mmHg, $PaCO_2$ 48.2 mmHg, and $SaO_2$ 87.7%. And the mean values of each parameters in the pulmonary function test were VC 2.05 L, $FEV_1$ 0.92 L, and $FEV_1$/FVC% 51.9%. Nineteen patients have used oxygen tanks as oxygen devices, 1 patient oxygen concentrator, 2 patients oxygen tank and liquid oxygen, and other 4 patients oxygen tank together with portable oxygen. The duration of oxygen therapy was below 1 year in 3 cases, 1~2 years in 15 cases, 3~5 years in 6 cases, 9 years in 1 case, and 10 years in 1 case. All patients have inhalated oxygen with flow rate less than 2.5 L/min. And only 10 patients have inhalated oxygen more than 15 hours per day, but most of them short time per day. Conclusion: For the effective oxygen administration, it is necessary that education for long-term low flow oxygen therapy to patients, their family and neighbor should be done, and also the institutional backup for getting convenient oxygen devices is required.

• Journal of Chest Surgery
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• v.29 no.11
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• pp.1218-1222
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• 1996

The reported incidence of postcardiotomy cardiogenic shock not responding to conventional therapy is still 0.1 to 0.8%. For this group of patients, more aggressive form of circulatory support must be employed. Centrifugal pumps are a ventricular assist device most commonly used on this purpose, due to low cost and easy availability. Currently, however, clinical experience of centrifugal pumps as a ventricular assist device is rarely reported in Korea. From January 1992 to January 1996, 2986 patients underwent cardiac operations on cardiopulmonary bypass at Seoul National University Hospital. Refractory postcardiotomy cardiac failure requring ventricular support with a Biomedicus centrifugal pump developed in ten of these patients. There were eight men and two women, ranged in age from nine years to 77 years with a mean of 50$\pm$20 years. The primary surgical procedures consisted of isolated coronary revascularization in four patients, combined coronary revascularization and aortic valve replacement in two, aortic dissection repair in two, pulmonary embolectomy in one, and heart transplantation in one. Of the ten patients, five had left ventricular assistance, one had right ventricular assistance, and four had biventricular assistance. Duration of ventricular assistance ranged from 24 to 175 hours, with a mean of 76$\pm$51 hours. Seven patients were weaned from ventricular assistance, and four of them discharged. The causes of death for nonsurvivors were progressive cardiac failure in two patients and multiorgan failure, intractable ventricular fibrillation, irreversible brain injury, and mechanical problem, respectively, in the other four. Survival was not predicted by time on cardiopulmonary bypass, aortic cross-clamp time, or duration of ventricular support. Major complications included bleeding(7), renal failure(6), infection(3) and neurologic complication(2). These results indicate that a centrifugal pump can provide reasonably satisfactory short-term circulatory support.

• Journal of Chest Surgery
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• v.38 no.2 s.247
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• pp.110-115
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• 2005

Background: The aims of this paper were to review the mid term clinical results and to analyze the preoperative risk factors of isolated aortic valve replacement (AVR). Material and Method: Between January 1992 and February 2003, 80 patients underwent isolated AVR. 58 were male and 22 were female patients, raging from 12 to 75 years of age (mean :$46.8{\pm}13.0$ years). 74 patients except one early death and 5 follow-up loss were contacted by OPD or by telephone. The mean duration of follow-up was $44.2{\pm}29.7$ months and the total cumulative period was 272.8 patient-year. Result: The complications in hospital occurred in 35 cases : 12 wound problems (11 superficial, 1 deep), 11 arrhythmias (9 temporary, 2 persistent), 3 low cardiac output, and so forth. The late deaths were 4 cases : the heart-related deaths were 2 cases ($0.7\%$ patient-year). Conclusion: The risk factors that influenced the early mortality and morbidity were older age (> 60 years)(p=0.04), poor preoperative NYHA functional class (> 3) (p=0.048), high preoperative serum creatinin level (> 1.2 mg/100 ml)(p=0.031), long operation time (aortic clamping time>90 min)(p=0.042). The same factors influenced the late mortality and morbidity. Freedom from valve-related complication was $86.4{\pm}5.3\%,$ actuarial survival rate were $96.8{\pm}2.3\%$ at 3 years and $90.8{\pm}4.6\%$ at 10 years.