• 한국재료학회지
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• 제5권3호
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• pp.357-363
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• 1995

PECVD(Plasma-enhanced Chemical Vapor Deposition)법을 이용하여 증착한 $Ta_{2}$O_{5}$ 박막의 전기적 특성과 미세구조에 미치는 RTA(Rapid Thermal annealing) 후속 고온 열처리의 영향을 조사하였다. $Ta_{2}$O_{5}$ 박막의 미세구조와 interface 거동을 관찰하기 위하여XRD(X-ray Diffractometer), TEM(Transmission Electron Microscope), AES(Auger Electron Spectroscope) 분석을 실시하였으며, 전기적 특성을 관찰하기 위하여 I-V, C-V 측정을 하였다. $600^{\circ}C$에서 60초간 열처리를 실시하였을 경우 가장 우수한 유전 특성 및 누설 전류 특성을 보였으며, 유전 상수는 26이었고 누설 전류는 5 $\times$ $10^{-11}$A/$cm^{2}$이었다. $600^{\circ}C$ 이상의 온도에서 행한 열처리에 의하여 박막의 누설 전류와 유전 특성은 복합적으로 영향을 받았음을 알 수 있었다. 이는 $600^{\circ}C$의 열처리에서 이루어지고있는 박막의 결함감소와 고밀화 현상과 함께 80$0^{\circ}C$ 이상의 열처리에서 발생하는 조밀육방정 결정 구조를 가지는 $\delta$-$Ta_{2}$O_{5}$의 결정화에 기인함을 알 수 있었다. 또한 TEM과 AES분석 결과로부터 이들 박막의 누설 전류와 유전상수의 변화는 열처리에 의하여 일어나는 Ta-O-Si transition층의 생성과 성장에 기인함을 알 수 있었다. 따라서 $Ta_{2}$O_{5}$ 박막의 전기적 특성의 변화는 RTA 후속 열처리에 따른 계면 반응과 결정화 그리고 박막의 조밀화에 그 영향이 있음을 알 수 있었다.

• 한국수정란이식학회지
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• 제25권4호
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• pp.237-245
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• 2010

Only an optimum number of viable spermatozoa in a frozen-thawed insemination dose can ensure conception at artificial insemination (AI). We report here the percentages of normal, abnormal and viable spermatozoa present in the frozen-thawed semen of 20 Black Bengal bucks used for commercial AI. Bucks in this experiment were of 19.3~46.1 months old and 25~42 kg body weight. Four semen straws (0.25 ml) from each buck were collected for evaluation of their kinetic parameters. Scrotal circumference was measured by using a scrotal tape, sperm motility was estimated on eye estimation and sperm concentration was determined by using a haemocytometer. Sperm morphology was studied in paraformaldehyde fixed spermatozoa under differential interference contrast (DIC) microscope. To determine the proportion of live (plasma membrane intact) spermatozoa, semen was stained with SYBR-14 and propidium iodide and examined under fluorescent microscope. Scrotal circumference, post-thaw sperm motility, sperm concentration per insemination dose and proportion of normal spermatozoa were $21.5{\pm}0.7\;cm$, $43.5 {\pm}5.4%$, $83.5{\pm}6.7$ million and $88.3{\pm}4.1%$, respectively. The percentages of spermatozoa with head shape and acrosome abnormalities were lower ($2.7{\pm}1.1$ and $1.4{\pm}1.3$, respectively), whereas higher percentages of abnormalities ($7.0{\pm}1.8$) were observed in mid piece and tail portion. The proportion of live spermatozoa was $28.5{\pm}5.4$. It is concluded that although a good number of morphologically normal spermatozoa are present in the insemination dose, the proportion of live spermatozoa is low, which warrants further improvements of buck semen freezing procedures to ensure good quality at AI.

• 한국재료학회지
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• 제28권2호
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• pp.118-123
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• 2018

5 nm-thick $SiO_2$ layers formed by plasma-enhanced chemical vapor deposition (PECVD) are densified to improve the electrical and interface properties by using nitric acid oxidation of Si (NAOS) method at a low temperature of $121^{\circ}C$. The physical and electrical properties are clearly investigated according to NAOS times and post-metallization annealing (PMA) at $250^{\circ}C$ for 10 min in 5 vol% hydrogen atmosphere. The leakage current density is significantly decreased about three orders of magnitude from $3.110{\times}10^{-5}A/cm^2$ after NAOS 5 hours with PMA treatment, although the $SiO_2$ layers are not changed. These dramatically decreases of leakage current density are resulted from improvement of the interface properties. Concentration of suboxide species ($Si^{1+}$, $Si^{2+}$ and $Si^{3+}$) in $SiO_x$ transition layers as well as the interface state density ($D_{it}$) in $SiO_2/Si$ interface region are critically decreased about 1/3 and one order of magnitude, respectively. The decrease in leakage current density is attributed to improvement of interface properties though chemical method of NAOS with PMA treatment which can perform the oxidation and remove the OH species and dangling bond.

• 한국임상수의학회지
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• 제26권3호
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• pp.200-204
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• 2009

This study was performed to evaluate the effects of reduced L-glutathione on the oxidant/antioxidant status(superoxide dismutase(SOD), catalase(CAT), glutathione peroxidase(GPx), protein carbonyl and lipid hydroperoxide(LPO) concentration), renal function(blood urea nitrogen(BUN) and serum creatinine levels), and microscopy of renal tissues in pigs undergoing unilateral renal ischemia-reperfusion(I/R). Sixteen Landrace and Yorkshire mixed-breed pigs were divided randomly into two groups: untreated control group and reduced L-glutathione-treated group(4 mg/kg IV). Each group had 8 pigs. Pigs were unilaterally nephrectomized and the kidney was subject to 30 min of renal pedicle occlusion. Blood samples for biochemical assay were collected on days 1, 3, 5, 7, and 14 post nephrectomy. Renal I/R injury were evaluated histopathologically by the microscopic observation of renal tissue sections and biochemically by the measurement of the plasma creatinine and urea levels. Parameters of oxidative stress such as SOD, GPx, CAT, protein carbonyl and LPO were measured. The elevation of creatine and BUN levels was lower in the treated group, compared with the control group. The activities of antioxidant-enzyme were higher in the treated group, compared with the control group. In histological findings, the severity of damage in the reduced L-glutathione treated group was less when compared to the control group.

• Journal of Periodontal and Implant Science
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• 제34권3호
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• pp.509-522
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• 2004

This study was performed to compare the clinical effectiveness of two regenerative techniques for class II furcation involvements in human: a combination of bone grafts with PRP vs. GTR with bone grafts. The e-PTFE group was treated with non-absorbable membrane and bone grafts, the PRP group was treated with PRP and bone grafts Pocket depth, clinical attachment level, and gingival recession were measured at baseline and postoperative 6 months. Vertical and horizontal furcation depth were measured by re-entry surgeries at 6 months post-treatment Both groups were statistically analyzed by Wilcoxon signed Ranks Test & Mann-whitney Test using SPSS program (5% significance level). The results were as follows: 1. The change of pocket depth, clinical attachment level, vertical furcation depth and horizontal furcation depth in both groups was decreased significantly at 6 months than at baseline. (p<0.05) 2. The change of gingival recession in both groups was increased significantly at 6 months than at baseline. (p<0.05) 3. The change of alveolar crest absorption in both groups was increased at 6 months than at baseline but there were no statistically significant differences. 4. The change of pocket depth, clinical attachment level, vertical furcation depth and horizontal furcation depth in both groups was increased significantly at 6 months, but there were no statistically or clinically significant differences with both groups. 5. The change of gingival recession and alveolar crest absorption in both groups was increased at 6 months, but there were no statistically or clinically significant differences with both groups. In conclusion, the use of bone graft with PRP or GTR technique improved clinical index of the soft and hard tissue in mandibular class II furcation involvement but there were no statistically or clinically significant differences between bone graft with PRP and GTR technique.

• 한국광학회지
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• 제18권2호
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• pp.149-154
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• 2007

저가의 소자 개발이 가능한 나노임프린팅 공정을 도입하여 510 nm 주기의 브래그 격자 구조를 가지는 폴리머 광도파로 소자를 제작하였다. 폴리머 격자 광소자의 온도 의존성을 감소시키기 위한 방법으로 플라스틱 박막으로 이루어진 유연성 기판상에 브래그 격자를 제작하는 것이 필요하다. 임프린팅 공정을 손쉽게 수행하기 위한 광도파로 구조를 채택하였으며, 코아와 클래딩의 굴절률이 각각 1.540, 1.430인 폴리머를 이용하여 코아 두께가 $3{\mu}m$인 단일모드 광도파로 구조를 얻을 수 있었다. 유연성 기판 브래그 격자 광도파로 소자의 특성을 Si기판 브래그 격자 광도파로 소자와 비교하여 관측한 결과, 유연성 기판 도입에 따른 브래그 반사 소자의 성능 저하는 나타나지 않았다.

• Molecules and Cells
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• 제38권10호
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• pp.829-835
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• 2015

It has been suggested that AUXIN BINDING PROTEIN 1 (ABP1) functions as an apoplastic auxin receptor, and is known to be involved in the post-transcriptional process, and largely independent of the already well-known SKP-cullin-F-box-transport inhibitor response (TIR1) /auxin signaling F-box (AFB) ($SCF^{TIR1/AFB}$) pathway. In the past 10 years, several key components downstream of ABP1 have been reported. After perceiving the auxin signal, ABP1 interacts, directly or indirectly, with plasma membrane (PM)-localized transmembrane proteins, transmembrane kinase (TMK) or SPIKE1 (SPK1), or other unidentified proteins, which transfer the signal into the cell to the Rho of plants (ROP). ROPs interact with their effectors, such as the ROP interactive CRIB motif-containing protein (RIC), to regulate the endocytosis/exocytosis of the auxin efflux carrier PIN-FORMED (PIN) proteins to mediate polar auxin transport across the PM. Additionally, ABP1 is a negative regulator of the traditional $SCF^{TIR1/AFB}$ auxin signaling pathway. However, Gao et al. (2015) very recently reported that ABP1 is not a key component in auxin signaling, and the famous abp1-1 and abp1-5 mutant Arabidopsis lines are being called into question because of possible additional mutantion sites, making it necessary to reevaluate ABP1. In this review, we will provide a brief overview of the history of ABP1 research.

• 한국수정란이식학회지
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• 제24권4호
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• pp.275-279
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• 2009

The beneficial effect of glycerol as a cryoprotectant, especially for sperm cryopreservation, has been shown in many studies. However, glycerol is toxic to living cells, and boar sperm in particular show greater sensitivity to glycerol than sperm from other domestic animals. Amides have been studied as alternative cryoprotectants for freezing stallion sperm. Sperm frozen in methylformamide or dimethylformamide as cryoprotectants show similar motility when thawed compared with sperm frozen in glycerol. We evaluated the cryoprotective effects of dimethylformamide on boar sperm freezing. To test the effect of amides, the concentration of boar semen was adjusted to $10^9sperm/mL$, and seminal plasma was removed using Hulsen solution. After centrifugation, the pellet was diluted in modified-Modena B extender. Lactose-egg yolk (LEY) extender was used as the cooling extender. The freezing extender was madeed aaddition of the optimal amount of glycerol and amides to LEY-Glycerol-Orvus ES Paste extender, and this extender was used for the second dilution. Diluted sperm were frozen in liquid nitrogen using the 0.5 mL straw method. Sperm frozen in extender with glycerol as a cderol were compared with those frozen in extender including the different amides. Sperm were tested for motility, viability, the sperm chromatin structure assay, and normal apical ridge after thawing. The percent of motile sperm diluted in glycerol was as high as that in the stallion study (61%). Dimethylformamide showed positive effects on sperm quality and was better than glycerol. Methylformamide provided similar sperm quality as glycerol. Therefore, dimethylformamide is useful for reducing cryoinjury in boar sperm and is expected to be useful as an alternative cryoprotectant.

• 한국재료학회지
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• 제30권7호
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• pp.350-358
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• 2020

A variety of composite powders having different aluminum and carbon contents are prepared using various organic solvents having different amounts of carbon atoms in unit volume as ball milling agents for titanium and aluminum ball milling. The effects of substrate temperature and post-heat treatment on the texture and hardness of the coating are investigated by spraying with this reduced pressure plasma spray. The aluminum part of the composite powder evaporates during spraying, so that the film aluminum content is 30.9 mass%~37.4 mass% and the carbon content is 0.64 mass%~1.69 mass%. The main constituent phase of the coating formed on the water-cooled substrate is a non-planar α₂ phase, obtained by supersaturated carbon regardless of the alloy composition. When these films are heat-treated at 1123 K, the main constituent phase becomes γ phase, and fine Ti₂AlC precipitates to increase the film hardness. However, when heat treatment is performed at a higher temperature, the hardness is lowered. The main constitutional phase of the coating formed on the preheated substrate is an equilibrium gamma phase, and fine Ti₂AlC precipitates. The hardness of this coating is much higher than the hardness of the coating in the sprayed state formed on the water-cooled substrate. When hot pressing is applied to the coating, the porosity decreases but hardness also decreases because Ti₂AlC grows. The amount of Ti₂AlC in the hot-pressed film is 4.9 vol% to 15.3 vol%, depending on the carbon content of the film.

• Food Science and Biotechnology
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• 제17권4호
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• pp.713-717
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• 2008

In the present study, chronic effects of the hot water extracts of walnut seed (Juglans regia L.) (WSE) and Nelumbo nucifera seed (NSE) were investigated in mice exposed to 2 hr of restraint stress each day for 4 weeks. Corticosterone levels in serum were significantly increased in the vehicle-treated stressed group ($25\;{\mu}g/dL$) compared to that in the control group ($13\;{\mu}g/dL$). This stress induced gastric redness and lesions. However, treatment with WSE and/or NSE significantly protected the stomach from this lesion by 50-60% compared to that in the vehicletreated group. In the amygdala, the administration of WSE and/or NSE also reduced the immediate early gene (c-fos) expression by 70-90% vs. the vehicle-treated group. These suggest that WSE and/or NSE may reduce the appearance of symptoms induced by stress and these materials are useful as anti-stress foods, as natural products tend to be relatively safe compared to chemical products.