• Journal of applied mathematics & informatics
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• 제14권1_2호
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• pp.115-122
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• 2004

We characterize the additive operators preserving rank-additivity on symmetry matrix spaces. Let $S_{n}(F)$ be the space of all $n\;\times\;n$ symmetry matrices over a field F with 2, $3\;\in\;F^{*}$, then T is an additive injective operator preserving rank-additivity on $S_{n}(F)$ if and only if there exists an invertible matrix $U\;\in\;M_n(F)$ and an injective field homomorphism $\phi$ of F to itself such that $T(X)\;=\;cUX{\phi}U^{T},\;\forallX\;=\;(x_{ij)\;\in\;S_n(F)$ where $c\;\in;F^{*},\;X^{\phi}\;=\;(\phi(x_{ij}))$. As applications, we determine the additive operators preserving minus-order on $S_{n}(F)$ over the field F.

• 한국자기학회지
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• 제14권6호
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• pp.236-239
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• 2004

미소 자유자성층에 인접한 스핀필터층 (SFL; spin filter layer)을 갖는 Ta3/NiFe2/IrMn7/CoFe1/(NOL1)/CoFe2/Cu 1.8/CoFe( $T_{f}$)/Cu( $t_{SF}$ )/(NOL2)/Ta3.5 (두께단위 nm) 구조의 스페큘라 스핀밸브 (SSV; specular spin valve)를 마그네트론 스퍼터링 장치를 사용하여 제작하였다. 반강자성체 I $r_{22}$M $n_{78}$을 속박층으로 한 스핀필터 스페큘라 스핀밸브 (SFSSV; spin filter specular spin valve) 박막에 대하여 자유자성층의 두께 ( $t_{F}$)와 SFL의 두께 ( $t_{SF}$ )가 각각 1.5nm일 때 극대 자기저항 (MR; magnetoresistance)비 11.9%를 얻었으며, $t_{SF}$ 가 1.0nm으로 감소하여도 11%이상의 MR비를 유지하였다. 이것은 나노산화층 (NOL; nano-oxide layer)에 의한 스페큘라 전자와 SFL에 의한 전류분류효과의 증가 때문이다. 또한, 자유자성층과 피속박층 사이의 층간결합장 ( $H_{int}$; interlayer coupling field)은 RKKY력과 정자기결합력으로 설명할 수 있다. 자유자성층의 보자력 ( $H_{cf}$ ; coercivity of the free layer)은 기존의 스핀밸브 (TSV; traditional spin valve)에 비해 현저히 감소했으며, $t_{F}$가 1nm에서 4nm로 변하여도 4 Oe이하의 값을 유지하였다. 따라서 SFL의 삽입으로 자유자성층의 연자성 특성을 떨어뜨리지 않으면서 자유자성층 두께의 감소와 MR비의 향상을 가능하게 하였다.

• Journal of applied mathematics & informatics
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• 제28권5_6호
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• pp.1171-1184
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• 2010

In this paper, by using fixed point theorems in cones, the existence of positive solutions is considered for nonlinear m-point boundary value problem for the following second-order dynamic equations on time scales $({\phi}(u^{\Delta}))^{\nabla}+a(t)f(t,\;u(t))=0$, t $\in$ (0, T), $u(0)=\sum\limits^{m-2}_{i=1}a_iu(\xi_i)$, $\phi(u^{\Delta}(T))=\sum\limits^{m-2}_{i=1}b_i{\phi}(u^{\Delta}(\xi_i))$, where $\phi$ : R $\rightarrow$ R is an increasing homeomorphism and positive homomorphism and ${\phi}(0)=0$. In [27], we obtained the existence results of the above problem for an increasing homeomorphism and positive homomorphism with sign changing nonlinearity. The purpose of this paper is to supplement with a result in the case when the nonlinear term f is nonnegative, and the most point we must point out for readers is that there is only the p-Laplacian case for increasing homeomorphism and positive homomorphism due to the sign restriction. As an application, one example to demonstrate our results are given.

• Asian Pacific Journal of Cancer Prevention
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• 제16권13호
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• pp.5261-5264
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• 2015

Purpose: To examine the effectiveness of serum free-to-total prostate specific antigen ratio (%fPSA) for the detection of prostate cancer (PCa) in men with different serum total PSA (tPSA) categories. Materials and Methods: From January 2010 to December 2013, a total of 225 patients with lower urinary tract symptoms (LUTS) underwent tPSA and %fPSA measurements. Histological examination with calculation of Gleason score and whole body bone scans were performed in identified cases of PCa. Results: PCa was diagnosed in 44 (19.6%) patients and the remaining 181 patients had benign prostate disease. PCa was detected in 5 (23.8%), 13 (8.7%) and 26 (47.3%) cases with tPSA level ranges ${\leq}4ng/ml$, 4 to 10 ng/ml and >10 ng/ml, respectively. The average Gleason score was $7.2{\pm}0.2$. Some 6 (13.6%) out of 44 PCa patients had bone metastases. The sensitivity was 80% and specificity was 81.3% at the cut-off %fPSA of 15% in PCa patients with a tPSA level below 4 ng/mL. A lower %fPSA was associated with PCa patients with Gleason score ${\geq}7$ than those with Gleason score ${\leq}6$ ($11.7{\pm}0.98$ vs. $16.5{\pm}2.25%$, P=0.029). No obvious relation of %fPSA to the incidence of bone metastasis was apparent in this study. Conclusions: The clinical application of %fPSA could help to discriminate PCa from benign prostate disease in men with a tPSA concentration below 4 ng/mL.

• Journal of Radiation Protection and Research
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• 제46권4호
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• pp.178-183
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• 2021

Background: This study was carried out to provide environmental transfer parameter values to estimate activity concentrations of these radionuclides in agricultural crops when direct contamination occurred. Materials and Methods: Mass interception fractions (F_Bs) and weathering half-lives (T_ws) of ¹³¹I and radiocesium were calculated using openly available monitoring data obtained after the Fukushima Daiichi Nuclear Power Plant accident. F_B is the ratio between the initial radioactivity concentration of a radionuclide retained by the edible part of the plant (Bq·kg^-1 fresh weight [FW]) and the amount of deposited radionuclide in that area (Bq·m^-2). T_w values can be calculated using activity concentrations of crops decreased with time after the initial contamination. Results and Discussion: Calculated F_B and T_w values for ¹³¹I and radiocesium were mostly obtained for leafy vegetables. The analytical results showed that there was no difference of F_Bs between ¹³¹I and radiocesium by t-test; geometric mean values for leafy vegetables cultivated under outdoor conditions were 0.058 and 0.12 m²·kg^-1 FW, respectively. Geometric mean T_w value of ¹³¹I in leafy vegetables grown under outdoor conditions was 8.6 days, and that of radiocesium was 6.6 days; there was no significant difference between T_w values of these radionuclides by Wilcoxon rank sum test. Conclusion: There was no difference between ¹³¹I and radiocesium for F_Bs and T_ws. By using these factors, we would be able to carry out a rough estimation of the activity concentrations of ¹³¹I and radiocesium in the edible part of leafy crops when a nuclear accident occurred.

• 대한수학회보
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• 제47권4호
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• pp.777-785
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• 2010

Let X be a linear space and Y be a complete quasi p-norm space. We will show that for each function f : X $\rightarrow$ Y, which satisfies the inequality ${\parallel}{\Delta}_x^nf(y)\;-\;n!f(x){\parallel}\;{\leq}\;\varphi(x,y)$ for suitable control function $\varphi$, there is a unique monomial function M of degree n which is a good approximation for f in such a way that the continuity of $t\;{\mapsto}\;f(tx)$ and $t\;{\mapsto}\;\varphi(tx,\;ty)$ imply the continuity of $t\;{\mapsto}\;M(tx)$.

• Journal of Acupuncture Research
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• 제17권3호
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• pp.176-187
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• 2000

Objectives : This study was purposed to investigate the antioxidative effects of Paeoniae radix aqua-acupuncture solution(PR) on culture liver cell system, lipid peroxidation and antioxidative enzyme activities in tert-butyl hydroperoxide(t-BHP) treatmented conditions. Methods : Cultured normal rat liver cell(Ac2F) were prepared and incubated with or without PR(at 2% volume in culture medium). After 16~18hr, cells placed in DMEM medium without serum, and then incubated with 1mM t-BHP for 2hr. Viable cells were detected by MTT assay, and the levels of lipid peroxide(LPO) were measured by TBA method. And catalase activity was measured as the decrease in hydrogen peroxide absorbance at 240nm on spectrophotometer using 30mM hydrogen peroxide. Superoxide dismutase(SOD) were assayed by recording the inhibition of nitro blue tetrazolium reduction with xanthine and xanthine oxidase. Glutathione peroxidase(GPX) activity was determined by the modified coupled assay developed by Paglia and Lawrence. The reaction was started by addition of 2.2mM hydrogen peroxide as substrate. The change in absorbance at 340nm was measured for 1min on spectrophotometer. Glutathione-S-transferase(GST) activity was assayed with CDNB as substrate and enzyme activity of GST towards the glutathione conjugation of CDNB. Results : Cell killing was significantly enhanced by addition of t-BHP compared to those of untreated group. PR pretreated cell resisted the toxic effects of t-BHP. LPO levels of t-BHP treatment group were significantly higher than other groups. This increased level was significandy reduced by PR pretreatment. The t-BHP treatment resulted in a decrease of catalase, GPX and GST activities. By contrast, PR pretreatment markedly increased compare to those of untreated groups. Conclusions : T-BHP which can produce intracellular free radical was used for inducer of the peroxidation of cellular lipids. PR protected the cell death induced by t-BHP and significantly increased cell viabiliry in the normal rat liver cell, and showed effective inhibition of lipid peroxidation, and elevations of catalase, GPX and GST activities. These results suggested that PR might play a protective role in lipid peroxidation by free radicals.

• 한국식품영양과학회지
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• 제39권8호
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• pp.1126-1131
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• 2010

3T3-L1 지방세포에서 상업용 Bacillus subtilis 균주와 순창 민속마을 전통 청국장에서 분리한 Bacillus subtilis KC-3(KCCM 42923) 균주를 이용해 두유를 발효시키고 이를 발효하지 않는 두유와 지방 생성 억제 효과를 비교하였다. 렙틴의 분비량은 B. subtilis MYCO 10001 발효두유(F-MYCO)와 B. subtilis KC-3 발효두유(F-KC)에서 유의적으로 감소하였다. 이러한 지방 생성 억제 효과가 지방의 축적과도 관련이 있는지 알아보기 위하여 지방구를 관찰한 결과 두유와 발효두유 모두에서 축적된 지방의 양이 감소했고 그중 F-KC는 유의적으로 감소하여(p<0.05) 지방의 생성과 축적이 억제된 것을 알 수 있었다. 지방축적의 감소가 지방 분해와도 관련이 있는지 조사하기 위하여 글리세롤의 분비량을 측정하였는데 발효되지 않은 두유의 글리세롤 분비 정도는 control과 비슷하였으나 발효두유의 모든 군에서는 글리세롤의 분비량이 증가하였고 특히 F-KC에서 글리세롤 분비량이 유의적으로 증가하였다. 또한 F-KC의 지방 축적 감소가 지방 생성 억 제로부터 기인된 것인지 조사하기 위하여 지방생성에 중추적 역할을 맡고 있는 전사인자인 $PPAR{\gamma}$와 SREBP-1c의 mRNA 발현을 확인한 결과 두유나 다른 발효두유에 비하여 F-KC에서 이들 유전자 발현이 감소한 것으로 나타났다. 따라서 B. subtilis KC-3에 의해 발효된 두유의 항비만 효과는 지방 생성의 중요한 전사인자인 $PPAR{\gamma}$와 SREBP-1c의 발현 억제에 기인한 것으로서 그 결과 지방의 생성을 억제하고 지방 축적을 효과적으로 감소 시키는 것으로 보인다.

• 상하수도학회지
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• 제20권6호
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• pp.885-892
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• 2006

In order to investigate whether or not Total Coliforms (T.C.) and Fecal Coliforms (F.C.) are compatible as indicator microorganisms of waterbome enteric viruses, a total of 192 surface water samples from 24 locations in Korea were tested for T.C., F.C., and human enteric viruses from July 2003 to January 2006. Altogether, the number of T.C. in each samples was ranged from $0{\sim}5.3{\times}10^4$ colony forming unit(CFU)/100mL, and the number of F.C. ranged from $0{\sim}5.0{\times}10^3CFU/100mL$ per sample. Thirty-three percent of the samples tested positive for human enteric viruses after the total culturable virus assay. The results of the statistical analysis showed that T.C. and F.C. had a significant correlation with turbidity and temperature, but the waterbome enteric viruses did not. When compared to the number of T.C. or F.C. per sample, the concentration of waterbome enteric viruses was not found to be correlated. In conclusion, it is suggested that T.C. and F.C. may not be sufficient microbial indicators of waterbome enteric viruses in the samples analyzed in this study. However, further research is needed to find other microbial indicators of waterbome enteric viruses and to develop more advanced and sensitive methods to detect waterborne enteric viruses.

• Kyungpook Mathematical Journal
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• 제48권4호
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• pp.637-650
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• 2008

New sufficient conditions for the existence of at least one solution of Neumann type boundary value problems for second order nonlinear differential equations $$\array{\{{p(t)\phi(x'(t)))'=f(t,x(t),\;x(\tau_1(t)),\;{\cdots},\;x(\tau_m(t))),\;t\in[0,T],\\x'(0)=0,\;x'(T)=0,}\,}$$, are established.