• Economic and Environmental Geology
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• v.30 no.1
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• pp.51-60
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• 1997

The high radon (Rn222) potentials of soil, groundwater, hotspring and indoor environments in the Taejon city area were delineated by use of an EDA RDA-200 radon detector. The U and Th contents were also analysed using a Multi Channel Analyzer to illustrate the sources of the radon potentials. The average U concentrations in Taejon vary according to the type of granites such as $4.14{\pm}2.36ppm$ in schistose granite (SG), $3.13{\pm}1.70ppm$ in biotite granite (BG) and $3.01{\pm}1.95ppm$ in two mica granite (TG). The U contents in the granites are closely related with the amounts of uraniferous minerals. However, the U contents in the soil are found to be $5.05{\pm}4.75ppm$ in TG, $4.07{\pm}1.69ppm$ in BG and $3.87{\pm}1.91ppm$ in SG which are mainly explained by the different cation exchange capacities (CEC) of the soils from various granites. The levels of soil radon are $552{\pm}656pCi/l$ in SG, in which levels at two locations exceed the level of 1,350 pCi/l established as guideline for follow-up action by the U.S. Environmental Protection Agency (EPA), $443{\pm}284pCi/l$ in TG and $224{\pm}115pCi/l$ in the BG. The soil radon concentrations are found to be proportional to the U content and hardness of the soils. The groundwater radon concentrations in the domestic wells of - 30~-100 m depth show that $6,907{\pm}4,665pCi/l$ in TG, $5,503{\pm}6,551pCi/l$ in SG and $2,104{\pm}1,157pCi/l$ in BG which are positively related with U contents in soils. The radon levels of six groundwater wells in TG and two in SG are greater than guideline for drinking water level, 10,000 pCi/l by EPA (1986). Average radon contents of hotsprings and public bathes in the TG area are $7,071{\pm}1,942pCi/l$ and $1,638{\pm}709pCi/l$, respectively, which are below the EPA standard for remedial action value of the 10,000 pCi/l. The mean indoor radon concentrations of the TG and SG areas are $1.60{\pm}1.20pCi/l$ and $1.60{\pm}0.70pCi/l$, respectively. The elevated indoor radon levels of 5.6 pCi/l and 6.7 pCi/l are found to be particularly in TG area, which exceeds 4 pCi/i guideline, correlating positively with the U contents in the soil and radon concentration in the groundwater.

• Bulletin of the Korean Mathematical Society
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• v.32 no.2
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• pp.139-144
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• 1995

Two subgroups U and V of a finite group G are called to be p-conjugate for a prime p if a Sylow p-subgroup of U is conjugate to a Sylow p-subgroup of V. This concept of p-conjugacy also makes sense for some infinite groups with a reasonable Sylow theory.

• Journal of Life Science
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• v.19 no.7
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• pp.871-877
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• 2009

We investigated the effects of sodium butyrate, a histone deacetylase inhibitor, on the cell cycle progression in human monocytic leukemia U937 cells. Exposure of U937 cells to sodium butyrate resulted in growth inhibition, G1 arrest of the cell cycle and induction of apoptosis in a dose-dependent manner as measured by MTT assay and flow cytometry analysis. The increase in G1 arrest was associated with the down-regulation in cyclin D1, E, A, cyclin-dependent kinase (Cdk) 4 and 6 expression, and up-regulation of Cdk inhibitors such as p21 and p27. Sodium butyrate treatment also inhibited the phosphorylation of retinoblastoma protein (pRB) and p130, however, the levels of transcription factors E2F-1 and E2F-4 were not markedly modulated. Furthermore, the down-regulation of phosphorylation of pRB and p130 by this compound was associated with enhanced binding of pRB and E2F-1, as well as p130 and E2F-4, respectively. Overall, the present results demonstrate a combined mechanism involving the inhibition of pRBjp130 phosphorylation and induction of Cdk inhibitors as targets for sodium butyrate that may explain some of its anti-cancer effects in U937 cells.

• Fisheries and Aquatic Sciences
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• v.15 no.3
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• pp.197-202
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• 2012

This study examined and compared the exopeptidase and endoprotease activities of the hepatopancreas (HP) of cuttlefish, squid, and octopus species. The protein concentration in crude extract (CE) from octopus HP was 3,940 mg/100 g, lower than those in CEs from squid HP (4,157 mg/100 g) and cuttlefish HP (5,940 mg/100 g). With azocasein of pH 6 as a substrate, the total activity in HP CE of octopus was 31,000 U, lower than the values for cuttlefish (57,000 U) and squid (69,000 U). Regardless of sample type, the total activities of the CEs with azocasein as the substrate were higher at pH 6 (31,000-69,000 U) than at pH 9 (19,000-34,000 U). With L-leucine-p-nitroanilide (LeuPNA) of pH 6 as the substrate, the total activity of the HP CE from octopus was 138,000 U, higher than values from both cuttlefish HP (72,000 U) and squid HP (63,000 U). Regardless of sample type, the total activities of the CEs with LeuPNA as the substrate were higher at pH 6 (63,000-138,000 U) than at pH 9 (41,000-122,000 U). With LeuPNA as the substrate, the total activities of the CEs from octopus HP and cuttlefish HP were higher at pH 6 than at pH 9. However, there was no difference in total activity between pH 6 and 9 for squid HP CE with LeuPNA as the substrate. These results suggest that the octopus HP is superior to the cuttlefish HP and squid HP as a potential resource for extracting exopeptidases. Exopeptidases from octopus HP have potential industrial applications and their use might aid in reducing pollution related to the octopus industry.

• Communications of the Korean Mathematical Society
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• v.26 no.2
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• pp.261-271
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• 2011

We consider the Hyers-Ulam-Rassias stability problem ${\parallel}2u{\circ}\frac{A}{2}-u{\circ}P_1-u{\circ}P_2{\parallel}{\leq}{\varepsilon}({\mid}x{\mid}^p+{\mid}y{\mid}^p)$, $x,y{\in}{\mathbb{R}}^n$ for the Schwartz distributions u, which is a distributional version of the Hyers-Ulam-Rassias stability problem of the Jensen functional equation ${\mid}2f(\frac{x+y}{2})-f(x)-F(y){\mid}{\leq}{\varepsilon}({\mid}x{\mid}^p+{\mid}y{\mid}^p)$, $x,y{\in}{\mathbb{R}}^n$ for the function f : ${\mathbb{R}}^n{\rightarrow}{\mathbb{C}}$.

• Proceedings of the Korean Geotechical Society Conference
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• 2005.03a
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• pp.998-1004
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• 2005

U.J.S.(Ultra Jetting System) is a new ground improvement method registered as a Utility Model No.0205798, which has fundamentally improved the existing jetting method of J.S.P.(Jumbo Special Pattern System). In this study, the uniaxial compressive strengths of improved soil-grout structures by U.J.S. and J.S.P. which have been conducted on the construction site are compared. Also, the differences between the U.J.S. and J.S.P. are analyzed by considering the role of the auger bit, the injection distance measured from the axis of boring tubes, and angle of injection measured from the horizontal. The specimens of soil-grout structures are taken from the improved soils by using the U.J.S. and J.S.P. The uniaxial tests for the samples are conducted after the curing period of 28 days. The uniaxial compressive strengths and the coefficients of elasticity of surface and distance from the axis of boring. This study shows that the mean strength of the improved structure by J.S.P. is 1.9 times greater than by J.S.P.

• Communications of the Korean Mathematical Society
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• v.9 no.2
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• pp.467-489
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• 1994

Let $\Omega$ be a closed and bounded polygonal domain in R$^2$, or a closed line segment in R$^1$ with boundary $\Gamma$, such that there exists an invertible mapping T : $\Omega$ \longrightarrow $\Omega$ with the following correspondence: x$\in$$\Omega$ ↔ x = T(x) $\in$$\Omega$, (1.1) and (1.2) t $\in$ U$\sub$p/($\Omega$) ↔ t = to T$\^$-1/ $\in$ U$\sub$p/($\Omega$), where $\Omega$ denotes the corresponding reference elements I = [-1,1] and I ${\times}$ I in R$^1$ and R$^2$ respectively, (1.3) U$\sub$p/($\Omega$) = {t : t is a polynomial of degree $\leq$ p in each variable on $\Omega$}, and (1.4) U$\sub$p/($\Omega$) = {t : t = to T $\in$ U$\sub$p/($\Omega$)}.(omitted)

• Journal of the Korean Society for Industrial and Applied Mathematics
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• v.11 no.2
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• pp.9-14
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• 2007

A signed 3-partite graph is a 3-partite graph in which each edge is assigned a positive or a negative sign. Let G(U, V, W) be a signed 3-partite graph with $U\;=\;\{u_1,\;u_2,\;{\cdots},\;u_p\},\;V\;=\;\{v_1,\;v_2,\;{\cdots},\;v_q\}\;and\;W\;=\;\{w_1,\;w_2,\;{\cdots},\;w_r\}$. Then, signed degree of $u_i(v_j\;and\;w_k)$ is $sdeg(u_i)\;=\;d_i\;=\;d^+_i\;-\;d^-_i,\;1\;{\leq}\;i\;{\leq}\;p\;(sdeg(v_j)\;=\;e_j\;=\;e^+_j\;-\;e^-_j,\;1\;{\leq}\;j\;{\leq}q$ and $sdeg(w_k)\;=\;f_k\;=\;f^+_k\;-\;f^-_k,\;1\;{\leq}\;k\;{\leq}\;r)$ where $d^+_i(e^+_j\;and\;f^+_k)$ is the number of positive edges incident with $u_i(v_j\;and\;w_k)$ and $d^-_i(e^-_j\;and\;f^-_k)$ is the number of negative edges incident with $u_i(v_j\;and\;w_k)$. The sequences ${\alpha}\;=\;[d_1,\;d_2,\;{\cdots},\;d_p],\;{\beta}\;=\;[e_1,\;e_2,\;{\cdots},\;e_q]$ and ${\gamma}\;=\;[f_1,\;f_2,\;{\cdots},\;f_r]$ are called the signed degree sequences of G(U, V, W). In this paper, we characterize the signed degree sequences of signed 3-partite graphs.

• Bulletin of the Korean Mathematical Society
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• v.54 no.3
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• pp.1023-1036
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• 2017

In this paper, we study the existence of positive solutions to the p-Kirchhoff elliptic equation involving general subcritical growth $(a+{\lambda}{\int_{\mathbb{R}^N}{\mid}{\nabla}u{\mid}^pdx+{\lambda}b{\int_{\mathbb{R}^N}{\mid}u{\mid}^pdx)(-{\Delta}_pu+b{\mid}u{\mid}^{p-2}u)=h(u)$, in ${\mathbb{R}}^N$, where a, b > 0, ${\lambda}$ is a parameter and the nonlinearity h(s) satisfies the weaker conditions than the ones in our known literature. We also consider the asymptotics of solutions with respect to the parameter ${\lambda}$.

• Nonlinear Functional Analysis and Applications
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• v.29 no.2
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• pp.333-360
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• 2024

This paper is concerned with the radial solutions of a nonlinear elliptic equation ∆_pu + |x|^𝑙₁ |u|^q₁-1 u + |x|^𝑙₂ |u|^q₂-1 u = 0, x ∈ ℝ^N, where p > 2, N ≥ 1, q₂ > q₁ ≥ 1, -p < 𝑙₂ < 𝑙₁ ≤ 0 and -N < 𝑙₂ < 𝑙₁ ≤ 0. We prove the existence of global solutions, we give their classification and we present the explicit behavior of positive solutions near the origin and infinity.