• Journal of the Korean Mathematical Society
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• v.48 no.3
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• pp.655-667
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• 2011

A class of functions involving divided differences of the psi and tri-gamma functions and originating from Kershaw's double inequality are proved to be completely monotonic. As applications of these results, the monotonicity and convexity of a function involving the ratio of two gamma functions and originating from the establishment of the best upper and lower bounds in Kershaw's double inequality are derived, two sharp double inequalities involving ratios of double factorials are recovered, the probability integral or error function is estimated, a double inequality for ratio of the volumes of the unit balls in $\mathbb{R}^{n-1}$ and $\mathbb{R}^n$ respectively is deduced, and a symmetrical upper and lower bounds for the gamma function in terms of the psi function is generalized.

• Journal of the Korean Mathematical Society
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• v.45 no.2
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• pp.559-573
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• 2008

In this paper, two classes of functions, involving a parameter and the classical Euler gamma function, and two functions, involving the classical Euler gamma function, are verified to be logarithmically completely monotonic in $(-\frac{1}{2},\infty)$ or $(0,\infty)$; some inequalities involving the classical Euler gamma function are deduced and compared with those originating from certain problems of traffic flow, due to J. Wendel and A. Laforgia, and relating to the well known Stirling's formula.

• Communications of the Korean Mathematical Society
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• v.22 no.2
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• pp.219-225
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• 2007

Since the time of Euler, the dilogarithm and polylogarithm functions have been studied by many mathematicians who used various notations for the dilogarithm function $Li_2(z)$. These functions are related to many other mathematical functions and have a variety of application. The main objective of this paper is to present corrected versions of two equivalent factorization formulas involving the Legendre's Chi-function $\chi_2$ and an evaluation of a class of integrals which is useful to evaluate some integrals associated with the dilogarithm function.

• Annals of Occupational and Environmental Medicine
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• v.35
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• pp.5.1-5.14
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• 2023

Background: Perfluoroalkyl substances (PFAS) are chemicals widely used in various products in everyday life. Due to its unique strong binding force, the half-life of PFAS is very long, so bioaccumulation and toxicity to the human body are long-standing concerns. In particular, effects on kidney function have recently emerged and there are no studies on the effect of PFAS on kidney function through epidemiological investigations in Korea. From 2018 to 2020, the Korean National Environmental Health Survey (KoNEHS) cycle 4, conducted an epidemiological investigation on the blood concentration of PFAS for the first time in Korea. Based on this data, the relationship between PFAS blood concentration and kidney function was analyzed for adolescents. Methods: We investigated 5 types of PFAS and their total blood concentration in 811 middle and high school students, living in Korea and included in KoNEHS cycle 4, and tried to find changes in kidney function in relation to PFAS concentration. After dividing the concentration of each of the 5 PFAS and the total concentration into quartiles, multivariable linear regression was performed to assess the correlation with kidney function. The bedside Schwartz equation was used as an indicator of kidney function. Results: As a result of multivariable linear regression, when observing a change in kidney function according to the increase in the concentration of each of the 5 PFAS and their total, a significant decrease in kidney function was confirmed in some or all quartiles. Conclusions: In this cross-sectional study of Korean adolescents based on KoNEHS data, a negative correlation between serum PFAS concentration and kidney function was found. A well-designed longitudinal study and continuous follow-up are necessary.

• The Journal of Korean Society for School & Community Health Education
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• v.20 no.3
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• pp.91-100
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• 2019

Purpose: The purpose of this study was to investigate the sexual function of male patients receiving rectal cancer and to analyze the factors related to sexual function. Methods: This study included 71 male patients undergoing outpatient treatment after surgery at C University Hospital, Chonnam, Korea from April 1 to September 1, 2014. The sexual function of males with colorectal cancer was calculated using the Korean Translation of International Index of Erectile Function(IIEF). Data analysis was performed using t-test, ANOVA, and regression analysis. The study was IRB approved. Results: The sexual function index scores of the subjects were 33.28±19.47 points. Regression analysis showed that sexual function increased as the duration after operation increased(p=.001), higher location of cancer(p=.007), age decreased(p=.013). The explanatory power (adj. R2) of the analysis model was 0.186. Conclusion: Sexual function of males with rectal cancer differed according to duration after operation, and location of cancer, age. Therefore, medical staff think that it can be used as basic data for appropriate education and counseling by age, time, and type of treatment to improve sexual function of men with rectal cancer.

• Journal of Minimally Invasive Surgery
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• v.21 no.4
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• pp.141-147
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• 2018

The rising incidence of early gastric cancer has enabled the development of function-preserving gastrectomy with the focus on post gastrectomy quality of life and adherence to sound oncologic principles. It is concurrent with the growing popularity of minimally invasive surgery; and both are commonly used together. The different kinds of function-preserving gastrectomy included in this review are: pylorus-preserving and proximal gastrectomy, vagus nerve preservation, sentinel node navigation, and various endoscopic & minimally-invasive techniques. In this article the indications, techniques, oncologic safety, functional benefit, and outcomes of each kind of function-preserving gastrectomy are discussed.

• Communications of the Korean Mathematical Society
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• v.27 no.3
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• pp.455-464
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• 2012

In the previous paper [8], the author gave a determinant formula of relative zeta function for cyclotomic function fields. Our purpose of this paper is to extend this result for more general function fields. As an application of our formula, we will give determinant formulas of class numbers for constant field extensions.

• Journal of applied mathematics & informatics
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• v.37 no.3_4
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• pp.307-315
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• 2019

In this paper we construct orthogonal two-direction scaling function of order 3 and corresponding wavelet function. In this paper we propose a different approach using orthogonal symmetric/antisymmetric multiwavelets of order 3. An example for constructing orthogonal two-direction scaling function of order 3 and corresponding wavelet function is given.

• East Asian mathematical journal
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• v.19 no.2
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• pp.213-219
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• 2003

We study the properties of non-diffenrentiable points of a self-similar Cantor function from which we conjecture a generalization of Darst's result that the Hausdorff dimension of the non-diffenrentiable points of the Cantor function is $(\frac{ln\;2}{ln\;3})^2$.

• Proceedings of the Korean Vacuum Society Conference
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• 2006.08a
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• pp.175-175
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• 2006