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        검색결과 88

        4.
        2019.12 KCI 등재후보 구독 인증기관 무료, 개인회원 유료
        This study aimed to examine the effect of a mild elevation in serum cholesterol level in a porcine coronary overstretch restenosis model using a balloon angioplasty catheter or drug-eluting coronary stent. Pigs were divided into two groups and were fed a commercial normal diet (CND, n = 4) or a high-fat diet (HFD, n = 4) for 5 weeks. Coronary overstretch injury by balloon angioplasty or stent implantation was induced in the left anterior descending and left circumflex artery after 1 week of feeding. Histopathological analysis was performed at 4 weeks after coronary injury. During the experiment, the total cholesterol level in the HFD group increased by approximately 44.9% (from 65.9 ± 3.21 mg/dL at baseline to 95.5 ± 9.94 mg/dL at 5 weeks). The lumen area in the CND group was reduced in comparison with that in the HFD group after balloon angioplasty. After stent implantation, the injury score showed no significant difference. There were significant differences in the neointimal area (2.7 ± 0.33 mm2 in the CND group vs. 3.3 ± 0.34 mm2 in the HFD group, p<0.05), lumen area (2.6 ± 0.54 mm2 in the CND group vs. 2.0 ± 0.33 mm2 in the HFD group, p<0.05), and percent area stenosis (52.0 ± 7.96% in the CND group vs. 62.4 ± 5.15% in the HFD group, p<0.05). Body weight change was not different between the two groups. Increased serum cholesterol level activated vascular smooth muscle cell proliferation in the porcine coronary overstretch model.
        4,000원
        5.
        2018.10 구독 인증기관·개인회원 무료
        최근 해충방제를 위해 유인헬기와 무인헬기를 이용한 수도작, 과수, 산림 등에서 대면적으로 약제살포가 이루어지고 있는 실정이다. 헬기는 비교적 높은 고도에서 비행하면서 약제를 살포하여 살포여건에 따라 약제가 목적이외의 지역으로 표류하여 부작용을 초래할 수도 있다. 따라서 본 연구는 소나무림의 소나무재선충 매개충과 밤나무림의 종실해충 방제지를 대상으로 유인헬기(소형, 대형)와 무인헬기(드론)의 약제살포 입자의 비산양상을 조사하고 다른 한편으로는 유·무인 헬기를 이용한 약제살포 실연을 통해 입자의 비산 양상을 조사하였다. 방제 실행지 조사에서 유인헬기(대형)의 경우 약제 입자의 최대 비산거리는 100 m였으며, 무인헬기(드론)의 경우 비산거리 30 m인 것으로 나타났다. 유무인 헬기를 이용한 실연 조사에 있어서도 약제입자의 최대 비산거리는 소형헬기의 경우 30 m, 대형헬기의 경우에는 100 m였으며, 드론의 경우에는 30 m로 나타났다. 동일한 조건에서 약제입자는 특정방향으로 비산되는 경향을 보여 풍향의 영향이 크게 미치는 것으로 판단되며 동일한 살포기종에 있어서 조사 시기에 따라 비산거리에 차이를 보이는 것은 약제살포 시간대의 풍속이 크게 영향을 미치는 것으로 판단된다.
        6.
        2017.06 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        We present a BV I optical photometric study of the old open cluster Ruprecht 6 using the data obtained with the SMARTS 1.0 m telescope at the CTIO, Chile. Its color-magnitude diagrams show the clear existence of the main-sequence stars, whose turn-o point is located around V  18:45 mag and B - V  0:85 mag. Three red clump (RC) stars are identi ed at V = 16:00 mag, I = 14:41 mag and B - V = 1:35 mag. From the mean Ks-band magnitude of RC stars (Ks = 12:39  0:21 mag) in Ruprecht 6 from 2MASS photometry and the known absolute magnitudes of the RC stars (MKS = - :595  0:025 mag), we obtain the distance modulus to Ruprecht 6 of (m -M)0 = 13:84  0:21 mag (d = 5:86  0:60 kpc). From the (J - Ks) and (B - V ) colors of the RC stars, comparison of the (B - V ) and (V - I) colors of the bright stars in Ruprecht 6 with those of the intrinsic colors of dwarf and giant stars, and the PARSEC isochrone ttings, we derive the reddening values of E(B - V ) = 0:42 mag and E(V - I) = 0:60 mag. Using the PARSEC isochrone ttings onto the color-magnitude diagrams, we estimate the age and metallicity to be: log(t) = 9:50  0:10 (t = 3:16  0:82 Gyr) and [Fe/H] = -0:42  0:04 dex. We present the Galactocentric radial metallicity gradient analysis for old (age > 1 Gyr) open clusters of the Dias et al. catalog, which likely follow a single relation of [Fe/H] = (-0:034  0:007)RGC + (0:190  0:080) (rms = 0.201) for the whole radial range or a dual relation of [Fe/H] = (-0:077  0:017)RGC + (0:609  0:161) (rms = 0.152) and constant ([Fe/H]  -0:3 dex) value, inside and outside of RGC  12 kpc, respectively. The metallicity and Galactocentric radius (13:28  0:54 kpc) of Ruprecht 6 obtained in this study seem to be consistent with both of the relations.
        4,600원
        13.
        2016.04 구독 인증기관·개인회원 무료
        Oxalic acid has a nematicidal activity against the root-knot nematode Meloidogyne incognita. High producer of oxalic acid was isolated, and then named as Aspergillus niger F22. Oxalic acid production was investigated under various temperatures from 20 – 33oC and rotational speeds in 5 L jar fermenters. Yield of oxalic acid increased with decreasing temperature. The highest yield was obtained at 23oC, showing the yield of oxalic acid of 8.7 g/L, whereas oxalic acid production was least at 33oC. At 20oC, the yield was lower than that of 23oC. At a rotational speed of 300 rpm, serious oxygen depletion was present from 48 - 72 h, resulting in low productivity of 26.2 mg /L·h. When a rotational speed was set at 600 rpm, dissolved oxygen tension was over 40% and oxalic acid production increased up to approximately 55%. Viscosity during the culture differed with temperatures. Viscosity increased with the increment of temperatures. When A. niger F22 was cultured at 23oC, viscosity was 810 cP, which was favorable for oxalic acid production.
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