• Nuclear Engineering and Technology
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• v.50 no.7
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• pp.1154-1159
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• 2018

Precise prediction of the radiation interaction position in scintillators plays an important role in medical and industrial imaging systems. In this research, the incident position of the gamma rays was predicted precisely in a plastic rod scintillator by using attenuation technique and multilayer perceptron (MLP) neural network, for the first time. Also, this procedure was performed using nonlinear regression (NLR) method. The experimental setup is comprised of a plastic rod scintillator (BC400) coupled with two PMTs at two sides, a $^{60}Co$ gamma source and two counters that record count rates. Using two proposed techniques (ANN and NLR), the radiation interaction position was predicted in a plastic rod scintillator with a mean relative error percentage less than 4.6% and 14.6%, respectively. The mean absolute error was measured less than 2.5 and 5.5. The correlation coefficient was calculated 0.998 and 0.984, respectively. Also, the ANN technique was confirmed by leave-one-out (LOO) method with 1% error. These results presented the superiority of the ANN method in comparison with NLR and the other methods. The technique and set up used are simpler and faster than other the previous position sensitive detectors. Thus, the time, cost and shielding and electronics requirements are minimized and optimized.

• Journal of the Korea Society for Simulation
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• v.28 no.3
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• pp.83-89
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• 2019

This research describes quantitative effects of initial dispersion conditions upon the dispersion randomness of Magnus rotor bomblets. Ratios of the missile spin rate to the missile velocity, a, flight path angles, ${\gamma}$ and altitudes, h, were changed to investigate their effects on dispersion randomness. Dispersion was analyzed through calculation of 6 degree of freedom motion equation with aerodynamic coefficients from wind tunnel experiments. In order to analyze the randomness, regression analysis is adopted to calculate the coefficient of determination. The optimized ratio of the missile spin rate to the missile velocity and flight path angle were obtained and the dispersion altitudes had more effect on the dispersion diameter and had less effect on dispersion than other parameters.

• Journal of Korean Society of Transportation
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• v.34 no.6
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• pp.560-569
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• 2016

Previous studies show that driver mental workload plays a significant role in the occurrence of traffic accidents. This study also analyzes driving workload under different road conditions especially with the brain wave data collected by a driving simulator. We use a logistic regression model to explain the relationship between driving workload and gamma brain waves. The results show that beta band of brain waves becomes broader with more curved sections while alpha band and gamma band become narrower. Since driving workload is negatively correlated with gamma band, it can be concluded that driving condition with less curved section is beneficial for reducing driving stress and increasing driving comfort.

• Journal of Nutrition and Health
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• v.39 no.8
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• pp.773-785
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• 2006

Vitamin E in the body system plays an important role in preventing chronic diseases by decreasing the oxidative stress by free-radicals. However, there are not enough researches on analyzing the primary factors affecting vitamin E levels in the blood in Korean adults. Therefore, the purpose of this research was to examine blood tocopherol levels and the primary factors affecting the status. A complete lifestyle survey was performed on 314 Korean adult men and surveyed their smoking, drinking and exercising habits. The average plasma level of ${\alpha}-\;and\;{\gamma}-tocopherol$ showed similar mutual relations with plasma total cholesterol (TC), triglyceride (TG), or low density lipoprotein cholesterol (LDL-C) levels (p<0.001). Plasma ${\alpha}-tocopherol$ level of the subjects did not show any difference as smoking, drinking and exercising habits changed. However, ${\gamma}-tocopherol$ per TG showed much lower figure in smokers than non smokers (p < 0.05). Amongst diet factors, plasma ${\alpha}-tocopherol$ level showed negative correlations with Vitamin E intake, while ${\gamma}-tocopherol$ level showed positive correlations with Vitamin E intake. Erythrocyte superoxide dismutase (SOD) activity and plasma tocopherol showed negative correlations, and catalase activity and plasma ${\alpha}-tocopherol$ showed positive correlationship. The level of cell DNA damage of Iymphocyte and plasma ${\alpha}-\;or\;{\gamma}-tocopherol$ showed negative correlations. As a result of this research, the factors that affect Korean adult men's plasma ${\alpha}-tocopherol$ level are plasma TG, LDL-C and cell DNA damage in Iymphocyte, while the factors that affect ${\gamma}-tocopherol$ level are plasma TG, LDL-C and vitamin E intake based on multiple regression analysis. These findings implies that the level of different types of tocopherol depends on slightly different factors. A further research is needed on the factors involved in the differentiation of the types of tocopherol.

• Asian Pacific Journal of Cancer Prevention
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• v.13 no.5
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• pp.1829-1831
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• 2012

Background: The generalized gamma distribution statistics constitute an extensive family that contains nearly all of the most commonly used distributions including the exponential, Weibull and log normal. A saturated version of the model allows covariates having effects through all the parameters of survival time distribution. Accelerated failure-time models assume that only one parameter of the distribution depends on the covariates. Methods: We fitted both the conventional GG model and the saturated form for each of its members including the Weibull and lognormal distribution; and compared them using likelihood ratios. To compare the selected parameter distribution with log logistic distribution which is a famous distribution in survival analysis that is not included in generalized gamma family, we used the Akaike information criterion (AIC; r=l(b)-2p). All models were fitted using data for 369 women age 50 years or more, diagnosed with stage IV breast cancer in BC during 1990-1999 and followed to 2010. Results: In both conventional and saturated parametric models, the lognormal was the best candidate among the GG family members; also, the lognormal fitted better than log-logistic distribution. By the conventional GG model, the variables "surgery", "radiotherapy", "hormone therapy", "erposneg" and interaction between "hormone therapy" and "erposneg" are significant. In the AFT model, we estimated the relative time for these variables. By the saturated GG model, similar significant variables are selected. Estimating the relative times in different percentiles of extended model illustrate the pattern in which the relative survival time change during the time. Conclusions: The advantage of using the generalized gamma distribution is that it facilitates estimating a model with improved fit over the standard Weibull or lognormal distributions. Alternatively, the generalized F family of distributions might be considered, of which the generalized gamma distribution is a member and also includes the commonly used log-logistic distribution.

• Journal of Korean Society of Forest Science
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• v.13 no.1
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• pp.79-84
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• 1971

This study is, by correlation and regression analysis, on the correlation between culm height and other growth factors which are circle at eye height and length of internode. The samples were come by in Tamyang district, To sum up, the results are as follows; 1. Two growth factors are much more correlative to culm height; both simple correlation and multiple correlation between the former and the latter are significant. ($r_{yx}=0.91$, $r_{yz}=0.78$, $r_{yx{\cdot}z}=0.84$, $r_{yz{\cdot}x}=0.55$, $R_{y{\cdot}xz}=0.94$) Seeing above significance, circle at eye height is more highly correlative than length of internode. 2. The following regression equation was derived from regression analysis. y= -0.687+0.335x+0.206z. y ; culm height. x ; circle at eye height. z ; length of internode. 3. By testing of the equation, regression coefficients are as follows; ${\beta}{\neq}O$, ${\gamma}{\neq}O$, ${\beta}{\neq}O{\neq}{\gamma}$ 4. The results tested the precision of the empirical formula, standard error of standard error by percentage are as follows. $Sy{\cdot}xz=0.89$, $Sy{\cdot}xz(%)=8.14$.

• Tuberculosis and Respiratory Diseases
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• v.43 no.1
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• pp.63-68
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• 1996

Background: Interferon-$\gamma$ has various biologic effects, including antiviral effect, antitumor proliferative effect, activation of macrophage and B lymphocyte, and increased expression of major histocompatibility complex. Especially, antitumor proliferative effect of interferon-$\gamma$ has already been proved to be important in vivo as well as in vitro. And, clinical studies of interferon-$\gamma$ have been tried in lung cancer patients. However, the mechanism of antitumor effect of interferon-$\gamma$ has not yet been established despite of many hypotheses. "Necrosis" is a type of cell death which is well known to occur in the circumstances of severe stresses. In contrast, "apoptosis" is another type of cell death which occurs in such biological circumstances as embryonic development, regression of organs, and self-tolerance of lymphocytes. And, apoptosis is an active process of cell death in which cells are dying with fragmentations of their cytoplasms and nuclei. And, in the process of apoptosis the DNAs of cells are cleaved between nucleosomes by unidentified endonuclease and therefore DNAs of apoptotic cells result in a typical electrophoresis pattern known as DNA ladder pattern. Recently it has been suggested that cytotoxic effect of interferon-$\gamma$ occurs via apoptosis. To elucidate the mechanism of antitumor cytotoxic effect of interferon-$\gamma$, we microscopically observed a lung cancer cell line, A549 which was treated with interferon-$\gamma$. We observed A545 treated with interferon-$\gamma$ was dying fragmented. And so, we performed this study to find out that the mechanism of antitumor cytotoxic effect of interferon-$\gamma$ be apoptosis. Method: We treated A549, human lung cancer cell line with various concentration of interferon-$\gamma$ and quantified its cytotoxic effect of various periods, 24 hours, 72 hours and, 120 hours by MTT(dimethylthiazolyl diphenyltetrazolium bromide) bioassay. Also, after we treated A549 with 100 units/mi of interferon-$\gamma$ for 120 hours, we observed the pattern of cell death with inverted microscope and we extracted DNAs from the dead A549 cells and observed the pattern of 1.5% agarose gel electrophoresis with ethidium bromide staining. Result: 1) Cytotoxic effect of interferon-$\gamma$ on A549: For the first 24 hours, threre was little cytotoxic effect and for between 24 hours and 72 hours, there was the beginning of cytotoxic effect and for 120 hours there was increased cytotoxic effect. 2) Pattern of A549 cell death by interferon-$\gamma$: We observed with inverted microscope that A549 cells were dying fragmented. 3) DNA ladder pattern of gel electrophoresis: We observed DNA ladder pattern of gel electrophoresis of extracted DNAs from dead A549 cells. Conclusion: We concluded that the mechanism of interferon-$\gamma$induced cytotoxicity on lung cancer cell line, A549 be via apoptosis.

• The Korean Journal of Pain
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• v.9 no.2
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• pp.349-353
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• 1996

Background: Although the paramedian approach for epidural blockade is useful in some clinical situation, the parameters which are correlated with the distance from skin to the epidural space has not been established. Methods: We studied in 143 patients having elective continuous epidural blocks for relief of postoperative pain. All blocks were performed using paramedian approach with Tuohy needle in the lumbar (group 1, n=100) and thoracic (group 2, n=45) area. We measured the distance from skin to the epidural space, body weight, height, and the angle between the shaft of the needle and the skin. Data were analyzed by linear regression. The relationships between parameters identified by the F-test with a P value of less than 0.05 were considered statistically significant. Results: The mean distance from skin to the lumbar epidural space was $4.4{\pm}0.7$ cm. significant correlation between the body weight and the depth of lumbar epidural space ($\gamma$ value : 0.492) was noted with regression equation of depth(cm)=2.293+0.034${\times}$body weight (kg). Also the significant correlation between the ponderal index (PI) and the depth of lumbar epidural space ($\gamma$ value : 0.539) was noted with regression equation of depth(cm)=1.703+0.07${\times}$PI, The mean distance from skin to the thoracic epidural space was $5.2{\pm}0.7cm$ which did not correlated with other anatomic measurements. Conclusion: We found that PI and body weight are the suitable predictors of the depth of the lumbar epidural space, but not the thoracic epidural space.

• Asian Pacific Journal of Cancer Prevention
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• v.16 no.5
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• pp.2099-2102
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• 2015

Objective: To explore the expression of $laminin{\gamma}2$ in extrahepatic cholangiocarcinoma (EHCC) tissues and its influence on tumor invasion and metastasis. Materials and Methods: Paraffin embedding samples of cancer, para-cancer, lymph node metastatic and hepatic metastatic tissues from 79 patients undergoing EHCC resection were collected. Expression of $laminin{\gamma}2$ was detected by immunohistochemistry and its relationship with clinical pathological characteristics and the prognosis of EHCC patients were analyzed. Results: $Laminin{\gamma}2$ showed negative staining in para-cancer tissues, but demonstrated a 51.9% (41/79) positive expression rate in extracellular matrix (ECM) or cytoplasm of EHCC tissues. In lymph node metastatic and distant metastatic nidi, expression of $laminin{\gamma}2$ was significantly higher than in the primary nidi (${\chi}^2=7.4173$, P=0.0065; ${\chi}^2=4.0077$, P=0.0453). The expression was in obvious association with lymph node metastasis (P<0.01), but had no relevance with age, gender, tumor location, tumor stage, differentiation and distant metastasis in ECM (P>0.05), whereas it was in marked connection with lymph node and distant metastasis (P<0.05 or P<0.01), but had no relationship with age, gender, tumor location, tumor stage and differentiation in cytoplasm (P>0.05). However, the median survival time and median recurrent period of patients with positive expression of $laminin{\gamma}2$ in both cytoplasm and ECM of tumor cells, only in ECM and only in cytoplasm, were evidently lower than with negative expression of $laminin{\gamma}2$ in RCM and cytoplasm (P<0.05 or P<0.01). Further Cox regression analysis showed that the positive expression of $laminin{\gamma}2$ and the tumor differentiation were independent risk factors influencing the prognosis of EHCC patients. Conclusions: Abnormal expression of $laminin{\gamma}2$ may be closely associated with invasion and metastasis of tumor cells, and thus a potential molecular marker for prognosis of EHCC patients.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.8
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• pp.3513-3518
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• 2014

The 14-3-3 protein has been shown to be involved in the cancer process. However, there is no understanding of the relationship between 14-3-$3{\gamma}$ (14-3-3 gamma) expression and prognosis in advanced non-small cell lung cancer. In this study, we therefore investigated the association between protein levels by immunohistochemistry and clinicopathological features of advanced NSCLC patients. Survival curves were estimated using the Kaplan-Meier method and tested by log-rank. Multivariate analysis was conducted with the Cox's regression model to determine independence of factors. p values less than 0.05 were considered significant. A total 153 patients were studied, with 54.3% being stage III and 45.8% stage IV. Fifty-one cases (33.3%) were squamous cell carcinomas, and 98 cases (64.1%) were adenocarcinomas. High 14-3-$3{\gamma}$ expression was seen in 59.5% and significantly correlated with lymph node metastasis (p=0.010) and distant metastasis (p=0.017). On Kaplan-Meier analysis, high 14-3-$3{\gamma}$ expression was associated with poorer survival with a marginal trend toward significance (p=0.055). On multivariate analysis, age, treatment, and 14-3-$3{\gamma}$ expression proved to be independent prognostic parameters. In vitro experiments indicated that 14-3-$3{\gamma}$ overexpression also played a potential role in cancer invasion. In conclusion, our data suggest that 14-3-$3{\gamma}$ overexpression is associated with invasion and a poor prognosis. Therefore, 14-3-$3{\gamma}$ may be a potential prognostic marker of advanced non-small cell lung cancer.