• Proceedings of the Korean Vacuum Society Conference
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• 2004.02a
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• pp.67-67
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• 2004

• Korean Journal of Environment and Ecology
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• v.28 no.5
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• pp.566-573
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• 2014

Decay rate and nutrient dynamics during leaf litter decomposition of deciduous broad leaf Quercus mongolica and evergreen needle leaf Pinus densiflora were investigated for 69 months from December 2005 to September 2011 in Mt. Worak National Park as a part of National Long-Term Ecological Research Program in Korea. Percent remaining weight of Q. mongolica and P. densiflora leaf litter after 69 months elapsed was $35.4{\pm}2.3%$ and $16.1{\pm}1.3%$, respectively. Decomposition of P. densiflora leaf litter was significantly faster than that of Q. mongolica leaf litter. Decay constant (k) of Q. mongolica and P. densiflora leaf litter after 69 months elapsed was 5.97 and 10.50, respectively. Initial C/N and C/P ratio of Q. mongolica leaf litter was 43.1 and 543.9 respectively. After 69 months elapsed, C/N and C/P ratio of decomposing Q. mongolica leaf litter decreased to 8.7 and 141.2, respectively. Initial C/N and C/P ratio of P. densiflora leaf litter was 151.2 and 391.4, respectively. After 69 months elapsed, C/N and C/P ratio of decomposing P. densiflora leaf litter decreased to 22.9. and 136.5. respectively. Initial concentration of N, P, K, Ca and Mg in leaf litter was 9.30, 0.23, 2.36, 3.14, 1.11 mg/g in Q. mongolica, and 3.02, 0.09, 1.00, 3.84, 0.62 mg/g in P. densiflora, respectively. Initial concentration of N and P in Q. mongolica leaf litter was significantly higher than those in P. densiflora. After 69 months elapsed, remaining N, P, K, Ca and Mg in decomposing leaf litter were 73.8, 60.9, 17.2, 20.3, 35.1 % in Q. mongolica, and 69.5, 75.3, 12.3, 10.9, 10.8 % in P. densiflora, respectively.

• Communications of the Korean Mathematical Society
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• v.10 no.1
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• pp.155-162
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• 1995

Let $\mu$ be a positive Borel measure on $R^n$ which is positive on cubes. For any cube $Q \subset R^n$, a Borel measurable nonnegative function $\varphi_Q$, supported and positive a.e. with respect to $\mu$ in Q, is given. We consider a maximal function $$ M_{\mu}f(x) = sup \int \varphi Q$\mid$f$\mid$d_{\mu} $$ where the supremum is taken over all $\varphi Q$ such that $x \in Q$.

• Korean Journal of Mathematics
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• v.23 no.4
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• pp.537-555
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• 2015

This paper is concerned with the existence of solutions to the following fractional differential inclusion $$\{-{\frac{d}{dx}}\(p_0D^{-{\beta}}_x(u^{\prime}(x)))+q_xD^{-{\beta}}_1(u^{\prime}(x))\){\in}{\partial}F_u(x,u),\;x{\in}(0,1),\\u(0)=u(1)=0,$$ where $_0D^{-{\beta}}_x$ and $_xD^{-{\beta}}_1$ are left and right Riemann-Liouville fractional integrals of order ${\beta}{\in}(0,1)$ respectively, 0 < p = 1 - q < 1 and $F:[0,1]{\times}{\mathbb{R}}{\rightarrow}{\mathbb{R}}$ is locally Lipschitz with respect to the second variable. Due to the general assumption on the constants p and q, the problem does not have a variational structure. Despite that, here we study it combining with an iterative technique and nonsmooth critical point theory, we obtain an existence result for the above problem under suitable assumptions. The result extends some corresponding results in the literatures.

• Kyungpook Mathematical Journal
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• v.55 no.1
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• pp.219-224
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• 2015

In this paper it is investigated as to when a nonempty invariant closed subset A of a $S^1$-space X containing the set of stationary points (S) can be the fixed point set of an equivariant continuous selfmap on X and such space X is said to possess the S-equivariant complete invariance property (S-ECIP). It is also shown that if X is a metric space and $S^1$ acts on $X{\times}S^1$ by the action $(x,p){\cdot}q=(x,p{\cdot}q)$, where p, $q{\in}S^1$ and $x{\in}X$, then the hyperspace $2^{X{\times}S^1}$ of all nonempty compact subsets of $X{\times}S^1$ has the S-ECIP.

• Journal of the Chungcheong Mathematical Society
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• v.32 no.1
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• pp.15-21
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• 2019

Let X be a reduced closed subscheme in ${\mathbb{P}}^n$ and $${\pi}_q:X{\rightarrow}Y={\pi}_q(X){\subset}{\mathbb{P}}^{n-1}$$ be an isomorphic projection from the center $q{\in}{\mathbb{P}}^n{\backslash}X$. Suppose that the minimal free presentation of $I_X$ is of the following form $$R(-3)^{{\beta}2,1}{\oplus}R(-4){\rightarrow}R(-2)^{{\beta}1,1}{\rightarrow}I_X{\rightarrow}0$$. In this paper, we prove that $H^1(I_X(k))=H^1(I_Y(k))$ for all $k{\geq}3$. This implies that Y is k-normal if and only if X is k-normal for $k{\geq}3$. Moreover, we also prove that reg(Y) ${\leq}$ max{reg(X), 4} and that $I_Y$ is generated by homogeneous polynomials of degree ${\leq}4$.

• Journal of applied mathematics & informatics
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• v.31 no.1_2
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• pp.199-209
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• 2013

In this paper, we study the oscillation problem of the following higher-order neutral differential equation with positive and negative coefficients and mixed arguments $$z^{(n)}(t)+q_1(t)|x(t-{\sigma}_1)|^{\alpha-1}x(t-{\sigma}_1)+q_2(t)|x(t-{\sigma}_2)|^{\beta-1}x(t-{\sigma}_2)=e(t)$$, where $t{\geq}t_0$, $z(t)=x(t)-p(t)x(t-{\tau})$ with $p(t)$ > 0, ${\beta}&gt;1&gt;{\alpha}&gt;0$, ${\tau}$, ${\sigma}_1$ and ${\sigma}_2$ are real numbers. Without imposing any restriction on ${\tau}$, we establish several oscillation criteria for the above equation in two cases: (i) $q_1(t){\leq}0$, $q_2(t)&gt;0$, ${\sigma}_1{\geq}0$ and ${\sigma}_2{\leq}{\tau}$; (ii) $q_1(t){\geq}0$, $q_2(t)&lt;0$, ${\sigma}_1{\geq}{\tau}$ and ${\sigma}_2{\leq}0$. As an interesting application, our results can also be applied to the following higher-order differential equation with positive and negative coefficients and mixed arguments $$x^{(n)}(t)+q_1(t)|x(t-{\sigma}_1)|^{\alpha-1}x(t-{\sigma}_1)+q_2(t)|x(t-{\sigma}_2)|^{\beta-1}x(t-{\sigma}_2)=e(t)$$. Two numerical examples are also given to illustrate the main results.

• Journal of Pharmaceutical Investigation
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• v.31 no.4
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• pp.225-232
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• 2001

The present study was carried out to observe the effect of liposome dispersed gel formulation (Lipogel) on topical delivery of ascorbyl palmitate (AsP). Neutral and negatively charged MLV liposomes containing AsP were prepared with dimyristoylphosphadtidylcholine (DMPC) and dicetyl phosphate (DCP), and dispersed to poloxamer gel matrix. In the hydrolysis study in rat's skin homogenates, AsP hydrolyzed to ascorbic acid (AsA) according to the first-order kinetics with the rate constant of $2.46{\times}10^{-2}\;min^{-1}$. In the passive skin penetration study using Franz diffusion cell, lipogel systems exhibited the greater values in the flux $(J_s)$ and the amount penetrated $(Q_p)$ compared to control hydrogels containing diethyleneglycol monoethyl ether $(Transcutol^{\circledR})$ as a solubilizing agent and a penetration enhancer for AsP. The total amount penetrated $(Q_{Total})$, which is expressed as a summation of $Q_P\;and\;Q_L$, for lipogel system was about 1.4 times higher in average than that of control hydrogel. However the amount localized in the skin $(Q_L)$ was similar in both formulations. As a result, lipogel system enhanced the skin penetration of AsP, possibly due to the increase in local concentration of AsP by preferential adsorption of liposome to the skin and the enhancing effect of phospholipid in liposome composition. Moreover it was expected that the penetrated AsP would generate AsA during skin penetration by the skin esterase. In conclusion, lipogel formulation was considered as a good candidate for topical delivery of AsP.

• The Korean Journal of Physiology and Pharmacology
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• v.25 no.4
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• pp.261-272
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• 2021

Doxorubicin (Dox) is widely used to the treatment of cancer, however, it could cause damage to gastric mucosa. To investigate the protective effects and related mechanisms of coenzyme Q10 (CoQ10) and vitamin C (VC) on Dox-induced gastric mucosal injury, we presented the survey of the 4 groups of the rats with different conditions. The results showed Dox treatment significantly induced GES-1 apoptosis, but preconditioning in GES-1 cells with VC or CoQ10 significantly inhibited the Dox-induced decrease and other harm effects, including the expression and of IκKβ, IκBα, NF-κB/p65 and tumor necrosis factor (TNF-α) in GES-1 cells. Moreover, high-throughput sequencing results showed Dox treatment increased the number of harmful gut microbes, and CoQ10 and VC treatment inhibited this effect. CoQ10 and VC treatment inhibits Dox-induced gastric mucosal injury by inhibiting the activation of the IkKB/IκBα/NF-κB/p65/TNF-α pathway, promoting anti-inflammatory effects of gastric tissue and regulating the composition of the intestinal flora.

• Biomedical Science Letters
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• v.22 no.3
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• pp.83-97
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• 2016

The measurement of viral load in HIV-1 infected patients is essential for the establishment of a therapeutic strategy. Several commercial assays have shown shortcomings in quantifying rare genotypes of HIV-1 such as minor groups of N and O. In this study, the HIV-1 RT-qPCR assay was developed. The primers and probe of HIV-1 were designed to target the pol gene and to increase the detection efficiency of various subtypes including group N and O. The HIV-1 quantitative RT-qPCR assay was assessed for its analytical performance and clinical evaluation. The LoD was determined to 33.9 IU/ml. The LoD of several subtypes including A, C, D, CRF_01AE, F, CRF_02AG, G and H, were determined to less than 40 IU/ml. The HIV-1 quantitative RT-qPCR assay was evaluated using the China National Reference Panel of HIV-1 RNA to determine the analytical performance. The results were all within the acceptable range. The clinical evaluation was performed at Hunan CDC in China. The clinical evaluation results were compared with those of the China domestic commercial kit. A significant correlation (fresh samples; $R^2=0.84$, P<0.001, frozen samples; $R^2=0.76$, P<0.001) between the two systems was observed for 64 fresh samples and 76 frozen samples with viral loads, and the Bland-Altman plot showed good agreement (98.4%, 96.1%, respectively). In conclusion, the HIV-1 quantitative RT-qPCR assay had comparable analytical performance with several commercial kits. The study provides basic data for the research of HIV-1 diagnosis and the development of P < HIV-1 molecular diagnostic assay.