• Journal of applied mathematics & informatics
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• v.41 no.1
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• pp.107-121
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• 2023

An epidemic infectious disease model consists of six compartments viz. Susceptible, Exposed, Infected, Quarantine, Recovered, and Virus with nonlinear saturation incidence rate is proposed to know the viral disease dynamics. There exist two biological equilibrium points for the model system. The system's local and global stability is done through Lyapunov's direct method about equilibrium points. The sensitivity analysis has been performed for the basic reproduction number and equilibrium points through the normalized forward sensitivity index. Sensitivity analysis shows that virus growth and quarantine rates are more sensitive parameters. In support of mathematical conclusions, numerical experimentation has been shown.

• Journal of Korean Biological Nursing Science
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• v.14 no.4
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• pp.275-281
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• 2012

Purpose: This study was performed to evaluate the effect of low-dose lidocaine on fentanyl-induced cough and hemodynamic changes under general anesthesia. This research was a randomized trial design and performed using a double-blind method. Methods: Data collection was performed from October 22, 2008, to May 4, 2009. One hundred and thirty two patients were randomly assigned to control group (Con G) and experimental group (Exp G) using a table of random numbers. Exp G (n=66) were administered 0.5 mg/kg lidocaine and Con G (n=66)) were administered saline. The occurrence of cough and vital sign were recorded within one minute after fentanyl bolus by an anesthesiologist. Collected data were analyzed using Repeated measures ANOVA using SPSS for Windows (Version 17.0). Results: The incidence of cough in Exp G was 13.6%, while Con G was 53%. The incidence cough in Exp G was significantly lower compared to Con G (p<.001). Lidocaine seemed not to suppress mean arterial pressure (p=.145), heart rate (p=.508), and oxygen saturation (p=.161). Conclusion: Intravenous administration of 0.5 mg/kg lidocaine seems to suppress fentanyl-induced cough without affecting mean blood pressure, heart rate and oxygen saturation. Therefore, we recommend intravenous 0.5 mg/kg lidocaine administration to suppress fentanyl-induced cough under general anesthesia.

• Journal of Korean Academy of Nursing
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• v.28 no.3
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• pp.529-539
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• 1998

Prematurity is the main cause for respiratory distress syndrome (RDS) in neonates. The goal in the treatment of RDS is to maintain respiration with adequate oxygenation. ETS needs to be performed to remove lung secretions in the ventilated premature infants with RDS. Oxygen saturation(SpO$_2$) and heart rate(HR) were compared in 22 premature infants with RDS using two types of ETS : open ETS versus close ETS. The results showed there was no significant difference in the SpO$_2$ and HR responses between open ETS and close ETS. The SpO$_2$ and HR returned to the baseline within 1 minute after suctioning. But in some case, there was a significantly greater incidence in the decrease of SpO$_2$ below 90% occured in the open ETS than in the close ETS. It implies that closed ETS may be beneficial to the premature infants who tend to develop desaturation easily.

• Journal of the Korean Society for Industrial and Applied Mathematics
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• v.22 no.1
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• pp.29-62
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• 2018

We investigate a class of HIV infection models with two kinds of target cells: $CD4^+$ T cells and macrophages. We incorporate three distributed time delays into the models. Moreover, we consider the effect of humoral immunity on the dynamical behavior of the HIV. The viruses are produced from four types of infected cells: short-lived infected $CD4^+$T cells, long-lived chronically infected $CD4^+$T cells, short-lived infected macrophages and long-lived chronically infected macrophages. The drug efficacy is assumed to be different for the two types of target cells. The HIV-target incidence rate is given by bilinear and saturation functional response while, for the third model, both HIV-target incidence rate and neutralization rate of viruses are given by nonlinear general functions. We show that the solutions of the proposed models are nonnegative and ultimately bounded. We derive two threshold parameters which fully determine the positivity and stability of the three steady states of the models. Using Lyapunov functionals, we established the global stability of the steady states of the models. The theoretical results are confirmed by numerical simulations.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2020.12a
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• pp.62-62
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• 2020

Ginseng is a shade-plant cultivated using shading facilities. However, at too low light levels, root growth is poor, and at high light levels, the destruction of chlorophyll reduces the photosynthesis efficiency due to leaf burn and early fall leaves. The ginseng has a lightsaturation point of 12,000~15,000 lux when grown at 15 to 20℃ and 9,500 lux at 25℃. This study was conducted to select the optimal light intensity of 3-year-old ginseng grown in blue-white film plastic house. The seeds were planted in the blue-white film plastic house with different light receiving rate (March 17, 2020). Between April and September, the average air temperature in the house was 20.4-20.7℃. Average soil temperature was 18.3℃-18.5℃. The chemical properties of the test soil was as follows. The pH level was 7.0-7.4, EC was 0.5-0.6 dS/m, OM was at the levels of 33.6-37.7 g/kg, P₂O₅ was 513.0-590.8 mg/kg, slightly higher than the allowable 400 mg/kg. The amount of light intensity, illuminance, and solar radiation in the blue-white film house was increased as the light-receiving rate increased and the amount of light intensity was found to be 9-14% compared to the open field, 8-13% illuminance and 9-14% solar irradiation respectively. The photosynthesis rate was the lowest at 3.1 µmolCO²/m²/s in the 9% light blue-white plastic house and 4.2 and 4.0 µmolCO²/m²/s in the 12% and 14% light blue-white plastic house, respectively. These results generally indicate that the photosynthesis of plants increases with the amount of light, but the ginseng has a lower light saturation point at high temperatures, and the higher the amount of light, the lower the photosynthetic efficiency. The SPAD (chlorophyll content) value decreased as the increase of light-receiving rate, and was the highest at 32.7 in 9% light blue-white plastic house. Ginseng germination started on April 11 and took 13-15 days to germinate. The overall germination rate was 82.9-85.8%. The plant height and length of stem were long in the 9% light-receiving plastic house. The diameter of stem was thick in the 12-14% light-receiving plastic house. In the 12% and 14% light-receiving plastic house, the length and diameter of taproot was long and thick, so the fresh weight of root per plant was 20 g or more, which was heavier than 16.9 g of the 9% light-receiving plastic house. The disease incidence (Alternaria blight, Gray mold and Damping-off etc.) rate were 0.9-2.7%. The incidence of Sclerotinia rot disease was 7.5-8.4%, and root rot was 0-20.0%. The incidence ratio of rusty root ginseng was 34.4-38.7% level, which was an increase from the previous year's 15% level.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.11 no.10
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• pp.891-896
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• 1998

The relaxation and elimination characteristics of polarization-photoinduced dichroism have been investigated in amorphous chalcogenide thin films deposited having normal(0。) and obique (80。) vapor incident angles. The dark relaxation kinetics of dichroism from a saturation point(D\ulcorner\ulcorner) to a certain relaxation point(D\ulcorner\ulcorner) grew to be longer on subsequent cycles of switching on and off of the inducing light, and these decays are changed from simple exponential decay to stretched exponential decay. The dichroism induced by a long time(~3.3 hrs) exposure exhibited the characteristics of longer time maintenance and smaller decreasing rate, in contrast with that by a short time (~min) exposure. In addition, the dichroism was eliminated by the exposure of non-polarized He-Ne laser.

• Horticultural Science & Technology
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• v.28 no.4
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• pp.529-534
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• 2010

Occurrence of wilted symptom in watermelon plant ($Citrullus$ $lanatus$ L.) is known to be caused by physiological disorder. The symptom results in the loss of fruit production and thus the economical loss of watermelon growers. The incidence of symptom is often found from the middle of March to the end of May in the major watermelon crop production areas of Korea (i.e. Uiryeong, Gyeongnam (lat $37^{\circ}$56'64"N, long $126^{\circ}$99'97"E)). Despite of extensive information about the physiological disorder, little study has been conducted to understand a relationship between the wilted symptom and accompanying environment factors (e.g. temperature). This study aimed to investigate effects of environmental conditions amended by a forced-ventilation system on physiological characteristics of watermelon and incidence of the wilted symptom. Watermelon plants were grown from January to May, 2009 with either the forced-or natural-ventilation treatment in a greenhouse located in the Uiryeong. In the result, the forced-ventilation treatment decreased the air, leaf and root-zone temperature approximately $4.5^{\circ}C$, $5^{\circ}C$ and $3^{\circ}C$, respectively, compared to the natural-ventilation. The fruit growth rate was maximized twice during the entire growing period. The higher rate of fruit growth was observed under the natural-ventilation than the forced one. Maximization of the fruit growth rate (approximately 430 g per day) was first observed by 12 days after fruiting under the natural-ventilation treatment, while the second one (approximately 350 g per day) was observed by 24 days after fruiting. The wilted symptom started occurring by 22 days after fruiting under the natural-ventilation, whereas no incidence of the symptom was found under the forced-ventilation treatment. Interestingly, the forced-ventilation lowered the fruit growth rate (approximately 320 g per day) compared to the natural one. Maximization of the fruit growth rate under the forced-ventilation was found at 4 days later than that under the natural one. This result coincided with a slower plant growth under the forced-ventilation treatment. These results suggest that the forced-ventilation slows down extension growth of fruit and plant, which may be associated with lowering leaf temperature and saturation deficit. We suggest the hypothesis that the forced-ventilation may alleviate stress of the wilted symptom by avoiding extreme water evaporation from leaves due to high temperature and thus by reducing competition between leaves and fruits for water. More direct and detailed investigations are needed to confirm the effect of the forced ventilation.

• The Korean Journal of Pain
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• v.19 no.1
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• pp.77-80
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• 2006

Background: Painful experiences during procedures such as prolotherapy and intramuscular stimulation are stressful to patients and can affect the treatment outcome. We present a method for relieving pain and increasing the level of patient comfort during the procedure. Methods: Twenty six patients who requested sedation anesthesia during the procedure were examined. All patients were injected with 500 ml of 0.9% normal saline and were monitored by electrocardiography, blood pressure and pulse oximetry. The patients were supplied with oxygen (3 L/min) through a nasal cannula. Midazolam (0.02 mg/kg) and alfentanil ($8{\mu}g/kg$) was injected before the procedure and a bolus injection was administered during the procedure if patients felt any pain. The duration of the procedure, the total amount of drugs, the changes in the systolic blood pressure, heart rate, pulse oxygen saturation, sedation and pain level during procedure, satisfaction scale after the procedure, complications and the incidence of amnesia were evaluated. Results: Twenty one patients had a moderate level of sedation, 15 patients did not feel any pain during the procedure, 17 patients had high level of satisfaction (8-10). No patient experienced complications after the procedure, or unstable vital signs, and 6 patients could not remember the procedure. Conclusions: Sedation anesthesia is a safe method for relieving pain during the procedure, and most patients had a high level of satisfaction.

• The Journal of the Korea Contents Association
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• v.14 no.11
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• pp.558-574
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• 2014

The number of fatty liver patients is sharply growing due to the rapid increase in the incidence of metabolic syndrome, which can lead to diseases such as abdominal obesity, hypertension, diabetes, and hyperlipidemia. Early diagnosis requires examinations using magnetic resonance imaging (MRI), wherein quantitative analyses are implemented through a professional water-fat separation method in many cases, as the intensity values of the areas of interest and non-interest are considerably similar or the same. However, such separation method generates inaccurate results in high magnetic fields, where the inhomogeneity of the fields increases. To overcome the limits of such conventional fat quantification methods, this paper proposes a field map estimation method that is effective in high magnetic fields. This method generates field maps through echo images that are obtained using the existing IDEAL sequences, and considers the wrapping degree of the field maps. Then clustering is performed to separate calibration areas, the least square fits based on the region growing method schema of the separated calibration areas, and the histograms are adjusted to separate the water from the fats. In experiment results, our proposed method had a superior fat detection rate of an average of 86.4%, compared to the ideal method with an average of 61.5% and Yu's method with an average of 62.6%. In addition, it was confirmed that the proposed method had a more accurate water detection rate of 98.4% on the average than the 88.6% average of the fat saturation method.

• Journal of Chest Surgery
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• v.36 no.7
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• pp.472-482
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• 2003

Recent studies have demonstrated that cerebral desaturation during rewarming period of CPB was associated with postoperative neurologic dysfunction. The prevention of cerebral desaturation during CPB may reduce the incidences of neurologic and neuropsychological complications. The present study was prospectively undertaken to compare the clinical effects between two strategies (hypercapnic CPB and high flow CPB) to prevent cerebral desaturation for establishing a proper CPB technique. Material and Method: Thirty-six adult patients scheduled for elective cardiac surgery were randomized into either hypercapnic (Pa$CO_2$ 45~50mmHg, n＝18) or high flow group (flow rate 2.75 L/ $m^2$/min and Pa$CO_2$ 35~40mmHg, n＝18) during rewarming period of CPB. In each patient, middle cerebral artery blood flow velocity ( $V_{MCA}$), cerebral arteriovenous oxygen content difference (C(a-v) $O_2$), modified cerebral metabolic rate for oxygen (MCMR $O_2$), cerebral oxygen transport rate ( $T_{E}$ $O_2$), incidence of cerebral desaturation (internal jugular bulb blood oxygen saturation $\leq$ 50%), increased rate of S-100 $\beta$ concentration, and arterial and internal jugular bulb blood gas were measured during the five phases of the operation; Pre-CPB, CPB-10 min (steady-state CPB, nasopharyngeal temperature 29~3$0^{\circ}C$), Rewarm-1 (rewarming phase, nasopharyngeal temperature 33$^{\circ}C$), Rewarm-2 (nasopharyngeal temperature 37$^{\circ}C$), and CPB-off. Incidence of postoperative delirium and duration were assessed in all patients. All variables were compared between the two groups. Result: $V_{MCA}$ (157.88$\pm$10.87 vs 120.00$\pm$6.18%, p＝0.006), internal jugular bulb $O_2$ saturation (68.01$\pm$2.75 vs 61.28$\pm$2.87%, p＝0.03) and $O_2$ tension (41.01$\pm$2.25 vs 32.02$\pm$ 1,67 mmHg, p＝0.03), and $T_{E}$ $O_2$(110.84$\pm$7.41 vs 81.15$\pm$8.11%, p＝0.003) at rewarming periods were higher in the hypercapnic group than in the high flow group. C(a-v) $O_2$ (4.0$\pm$0.30 vs 4.84$\pm$0.38 mg/dL, p＝0.04), COE (0.36$\pm$0.03 vs 0.42$\pm$0.03, p＝0.04), increased rate of S- 100$\beta$ (391.67$\pm$23.40 vs 940.0$\pm$17.02%, p＝0.003), and incidence of cerebral desaturation (2 vs 4 patients, p＝0.04) at rewarming periods, and duration of postoperative delirium (18 vs 34 hr, p＝0.02) were low in the hypercapnic group compared to the high flow group. Conclusion: These results indicate that hypercapnic CPB may provide relatively diminished cerebral injury and beneficial effects for cerebral metabolism relatively compared to high flow CPB.low CPB.