• Journal of Astronomy and Space Sciences
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• 제33권4호
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• pp.273-278
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• 2016

December 2009 was one of the quietest (monthly Ap=2) months over the last eight decades. It provided an excellent opportunity to study the day-to-day variability of the F2 layer with the smallest contribution due to geomagnetic activity. With this aim, we analyze hourly values of the F2-layer critical frequency (foF2) recorded at 18 ionosonde stations during the magnetically quietest (Ap=0) days of the month. The foF2 variability is quantified as the relative standard deviation of foF2 about the mean of all the "zero-Ap" days of December 2009. This case study may contribute to a more clear vision of the F2-layer variability caused by sources not linked to geomagnetic activity. In accord with previous studies, we find that there is considerable "zero-Ap" variability of foF2 all over the world. At most locations, foF2 variability is presumably affected by the passage of the solar terminator. The patterns of foF2 variability are different at different stations. Possible causes of the observed diurnal foF2 variability may be related to "meteorological" disturbances transmitted from the lower atmosphere or/and effects of the intrinsic turbulence of the ionosphere-atmosphere system.

• 충청수학회지
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• 제32권3호
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• pp.295-307
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• 2019

In this paper, we investigate Hyers-Ulam-Rassias stability of the functional equation $$f(x+ky)-{\frac{k^2+k}{2}}f(x+y)+(k^2-1)f(x)-{\frac{k^2-k}{2}}f(x-y)\\{\hfill{67}}-f(ky)+{\frac{k^2+k}{2}}f(y)+{\frac{k^2-k}{2}}f(-y)=0.$$

• Journal of Microbiology and Biotechnology
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• 제24권2호
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• pp.287-294
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• 2014

The transcription factor E2F1 is active during G1 to S transition and is involved in the cell cycle and progression. A recent study reported that increased E2F1 is associated with DNA damage and tumor development in several tissues using transgenic models. Here, we show that E2F1 expression is regulated by tristetraprolin (TTP) in prostate cancer. Overexpression of TTP decreased the stability of E2F1 mRNA and the expression level of E2F1. In contrast, inhibition of TTP using siRNA increased the E2F1 expression. E2F1 mRNA contains three AREs within the 3'UTR, and TTP destabilized a luciferase mRNA that contained the E2F1 mRNA 3'UTR. Analyses of point mutants of the E2F1 mRNA 3'UTR demonstrated that ARE2 was mostly responsible for the TTP-mediated destabilization of E2F1 mRNA. RNA EMSA revealed that TTP binds directly to the E2F1 mRNA 3'UTR of ARE2. Moreover, treatment with siRNA against TTP increased the proliferation of PC3 human prostate cancer cells. Taken together, these results demonstrate that E2F1 mRNA is a physiological target of TTP and suggests that TTP controls proliferation as well as migration and invasion through the regulation of E2F1 mRNA stability.

• 대한방사성의약품학회지
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• 제2권2호
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• pp.73-83
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• 2016

Imaging hypoxia using positron emission tomography (PET) is of great importance for cancer therapy. [$^{18}F$] Fluoromisonidazole (FMISO) was the first PET agent used for imaging tumor hypoxia. Various radiolabeled nitroimidazole derivatives such as [$^{18}F$]fluoroerythronitroimidazole (FETNIM), [$^{18}F$]1-${\alpha}$-D-(2-deoxy-2-fluoroarabinofuranosyl)-2-nitroimidazole(FAZA), 2-(2-nitroimidazol-1-yl)-N-(3,3,3-[18F]-trifluoropropyl)acetamide ([$^{18}F$]EF-3), [$^{18}F$]2-(2-nitro-1H-imidazol-1-yl)-N-(2,2,3,3,3-pentafluoropropyl) acetamide (EF-5), 3-[$^{18}F$]fluoro-2-(4-((2-nitro-1H-imidazol-1-yl)methyl)-1H-1,2,3,-triazol-1-yl)-propan-1-ol ([$^{18}F$]HX-4), and [$^{18}F$]fluoroetanidazole (FETA) were developed successively. However, these imaging agents still produce PET images with limited resolution; the lower blood flow in hypoxic tumors compared to normoxic tumors results in low uptake of the agents in hypoxic tumors. Thus, the development of better imaging agents is necessary.

• Journal of Ginseng Research
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• 제9권2호
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• pp.264-269
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• 1985

The inheritance of violet and green stems was examined in F1 F2 of violetstem variant x yellow-berry variant in Panax ginseng C. A. Meyer, and the characters of F1 and F2 plants were investigated. From these results, it was shown that most of the characters of F1 and F2 plants were simillar to the female plants. However, reciprocal crosses between violet and green stems yielded progeny of violet-stem variant. Thus the cross V♀x♂Y gave all violet-stem seedlings, and the cross Y♂ x Y♀ gave all violet-stem seedlings. And all of the crosses segregated in F2 in a ratio of 3 violet to 1 green.

• 한국결정성장학회지
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• 제9권1호
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• pp.1-5
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• 1999

Molecular beam epitaxy법으로 $CaF_{2}$ (111) 기판위에 희토류 이온 ($(Nd^{3+},\;Er^{3+})$) 첨가 $CaF_{2}$ 박막을 성장하였다. 첨가농도와 박막두께에 따른 희토류 첨가 $CaF_{2}$ 박막의 표면구조와 결정성을 RHEED로 검토하였다. 반도체 관련 고집적회로구조에 있어서의 완층막으로서의 응용을 고려하여, 희토류첨가 $CaF_{2}$ 박막과 $CaF_{2}$ (111) 기판과의 격자부정합의 변이를 X-ray rocking Curve 분석에 의해 검토하였다.

• 한국육종학회지
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• 제41권4호
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• pp.463-467
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• 2009

Allium 속 근연종인 파와 양파간 종간교잡을 이용하여 양파로부터 새로운 형질을 도입하는 과정에서 유래되는 종간교잡 F1과 여교잡 세대들의 게놈크기의 변화를 flow cytometry를 이용하여 측정한 결과 다음과 같은 결과를 얻었다. 1. 양파와 파의 종간교잡 F1의 식물학적 특성은 양친의 중간형을 보였으나 여교잡이 진전됨에 따라 반복친인 파의 표현형이 우세하였다. flow cytometry를 이용하여 2C nuclear DNA content을 측정한 결과 $F_1$은 양친에 비해 오히려 증가하였으나 여교잡이 진행됨에 따라 급속히 감소하여 $BC_2F_1$에서는 반복친과 비슷한 수준으로 감소하였다. 여교잡세대의 자식인 $BC_1F_2$은 반복친과 비슷한 $23.1{\pm}1.0pg$으로 측정되었으나 $BC_2F_2$는 $22.9{\pm}0.4pg$으로 반복친의 2C nuclear DNA content인 $23.2{\pm}0.2pg$ 보다 오히려 감소하였다.

• 충청수학회지
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• 제22권4호
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• pp.757-770
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• 2009

In this paper, we prove the generalized Hyers-Ulam stability of the following additive-quadratic-cubic-quartic functional equation (0.1) f(x + 2y) + f(x - 2y) = 4f(x + y) + 4f(x - y) - 6f(x) + f(2y) + f(-2y) - 4f(y) - 4f(-y) in Banach spaces.

• 대한음성학회지:말소리
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• 제61호
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• pp.15-29
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• 2007

The present study investigates acoustic cues of russian soft plosive consonants. In previous studies, russian soft consonants are distinguished from hard consonants by F1, F2 of following vowels. The result showed: (1) that F0 of soft plosive consonants in following vowels were lower than those of hard plosive consonants; (2) and that VOT of soft plosive consonants were longer than those of hard plosive consonants. Hence, the present that, in addition to F1, F2, VOT and F0 are detected as acoustic cues that differentiate soft plosive consonants from hard plosive consonant in Russian.

• Journal of Forest and Environmental Science
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• 제11권1호
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• pp.72-80
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• 1995

강원대학교 부속 연습림의 낙엽활엽수림에서 임상유기물(O층)의 집적에 미치는 표고의 영향을 조사하였다. 표고가 높아짐에 따라 O층의 두께는 증가하였으며, 이러한 경향은 F2층과 H층에서 뚜렷하였다. O층의 두께(X, cm)와 무게(Y, $kg/m^2$)의 관계는 직선회귀식 Y($kg/m^2$) = aX(cm)에 근사였으며, F2층, H층 및 F2 + H층에 대한 계수 "a" 의 값은 각각 0.43, 0.61 및 0.53이었다. 유기물의 용적중은 F2층, H층 및 F2+H층에서 각각 $45g/dm^2$, $60g/dm^2$ 및 $55g/dm^2$ 전후로 추정되었다. O층의 양은 표고 280m에서의 13ton/ha으로부터 표고 710m의 41ton/ha의 범위에 있었으며, F1, F2및 H층은 각각 5~10ton/ha, 5~11ton/ha 및 13~40ton/ha의 범위를 차지하였다.