• 한국결정성장학회지
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• 제8권1호
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• pp.97-105
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• 1998

$Al_2O_3-C$계 내화물에 Al 금속분말을 첨가하여 $800^{\circ}C$에서 $1400^{\circ}C$의 온도영역에서 탄소의 산화억제 메카니즘을 조사하였다. 탄소의 산화는 Al 금속분말을 5wt% 첨가한 $Al_2O_3-C-Al $ 시편에서 억제되었으며, 시편의 표면과 내부계면에 탄소가 비교적 균일하게 분포되어 있었다. Al-C 시편의 조성에서 중간생성물인 $Al_4C_3$ 및 AlN이 $800-1200^{\circ}C$의 온도범위에서 존재하였으며, $1400^{\circ}C$ 이상의 고온에서 모두 $Al_2O_3$로 전이하였다. $1000^{\circ}C$에서 1시간 가열한 Al-C 시편에서 $Al_4C_3$의 생성과 관계있는 cavity structure가 관찰되었다. 열역학적 고찰을 기초로 하여 산환억제 효과와 관계있는 $Al_4C_3$와 AlN의 생성, $Al_2O_3$로의 전이, C(s)의 형성등이 논하였다.

• Asian Pacific Journal of Cancer Prevention
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• 제16권3호
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• pp.1289-1293
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• 2015

Background: Anal intraepithelial lesions (AIL) are likely to represent a precursor for anal cancer. Women infected with human immunodeficiency virus (HIV) may be at higher risk of anal cancer but a screening program for AIL still is not routinely recommended. We here studied the relationship of dysplastic cells from cervical and anal cytology in HIV-infected women. Materials and Methods: This prospective study was conducted in Prapokklao Hospital, Thailand during 2013-2014. Five hundred and ninety nine HIV-infected women were recruited. Participants who had cytological reports of equally or over "abnormal squamous/glandular cells of undetermined significance" (ASC-US) were classified as abnormal cervical or anal cytology. Descriptive statistics and logistic regression analysis were used to evaluate correlations between groups. Results: HIV-infected women with abnormal cervical cytology had 3.8 times more risk (adjusted odd ratio 3.846, 95% confidence interval 1.247-11.862, p-value. 019) for abnormal anal cytology. The major problem of the anal Pap test in this study was the inadequacy of the collected specimens for evaluation (34.4%, 206/599). Sensitivity, specificity, positive predictive value, negative predictive value and accuracy of cervical and anal Pap tests were 93.9/12.0, 87.3/96.9, 39.7/21.4, 99.4/94.1 and 88.1/91.4 percent, respectively. Conclusions: Abnormal cervical cytology in HIV-infected women indicates elevated risk for abnormal anal cytology. The sensitivity of the anal Pap test for detection of AIL 2/3 in HIV-infected women was quite low while specificity was excellent. Inadequacy of specimen collection for evaluation was a major limitation. Improvement of sample collection is recommended for future investigations.

• Nuclear Engineering and Technology
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• 제52권10호
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• pp.2320-2327
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• 2020

The extreme hydrophobicity of expanded polytetrafluoroethylene (ePTFE) hinders bone-tissue integration, thus limiting the use of ePTFE in medical implant applications. To improve the potential of ePTFE as a biomaterial, 2-hydroxyethyl methacrylate (HEMA) was grafted onto the ePTFE surface using the gamma irradiation technique. The characteristics of the grafted ePTFE were successfully evaluated using attenuated total reflectance Fourier transform infrared (ATR-FTIR), field-emission scanning electron microscopy (FESEM)/energy dispersive X-ray (EDX), and X-ray photoelectron spectroscopy (XPS). Under the tensile test, the modified ePTFE was found to be more brittle and rigid than the untreated sample. In addition, the grafted ePTFE was less hydrophobic with a higher percentage of water uptake compared to the untreated ePTFE. The protein adsorption test showed that grafted ePTFE could adsorb protein, which was denoted by the presence of N peaks in the XPS analysis. Moreover, the formation of the globular mineral on the grafted ePTFE surface was successfully visualized using the FESEM analysis, with a ratio of 1.94 for Ca:P minerals by the EDX. To summarize, the capability of the modified ePTFE to show protein adsorption and mineralization indicates the improvement of the polymer properties, and it can potentially be used as a biomaterial for implant application.

• 대한치과교정학회지
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• 제49권4호
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• pp.205-213
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• 2019

Objective: The aim of this study was to evaluate the amount of tooth movement and histologic changes with different corticotomy designs and micro-osteoperforation in rabbits. Methods: The sample consisted of 24 rabbits divided into three experimental groups (triangular corticotomy [TC] and indentation corticotomy [IC] with flap, and flapless micro-osteoperforations [MP]) and a control. A traction force of 100 cN was applied by connecting the first premolars to the incisors. The amount of tooth movement was measured. Kruskal-Wallis test was used to assess differences in tooth movement between the groups. Micro-computed tomography, hematoxylin and eosin staining, and tartrate-resistant acidic phosphatase (TRAP) analysis were performed. Analysis of variance was applied to assess differences in TRAP-positive osteoclast count between the groups. Results: The amount of tooth movement increased by 46.5% and 32.0% in the IC and MP groups, respectively, while the bone fraction analysis showed 69.7% and 8.5% less mineralization compared to the control. There were no significant intergroup differences in the number of TRAP-positive osteoclasts. Conclusions: The micro-osteoperforation group showed no significant differences in the amount of tooth movement compared to the corticotomy groups, nor in the TRAP-positive osteoclast count compared to both corticotomy groups and control.

• Restorative Dentistry and Endodontics
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• 제43권4호
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• pp.46.1-46.10
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• 2018

Objectives: This study was to evaluate the antibacterial effect of different instrumentation and irrigation techniques using confocal laser scanning microscopy (CLSM) after root canal inoculation with Enterococcus faecalis (E. faecalis). Materials and Methods: Mesiobuccal and mesiolingual canals of extracted mandibular molars were apically enlarged up to a size 25 hand K-file, then autoclaved and inoculated with E. faecalis. The samples were randomly divided into 4 main groups according to the system of instrumentation and irrigation: an XP-endo Shaper (XPS) combined with conventional irrigation (XPS/C) or an XP-endo Finisher (XPF) (XPS/XPF), and iRaCe combined with conventional irrigation (iRaCe/C) or combined with an XPF (iRaCe/XPF). A middle-third sample was taken from each group, and then the bacterial reduction was evaluated using CLSM at a depth of $50{\mu}m$ inside the dentinal tubules. The ratio of red fluorescence (dead cells) to green-and-red fluorescence (live and dead cells) represented the percentage of bacterial reduction. The data were then statistically analyzed using the Kruskal-Wallis test for comparisons across the groups and the Dunn test was used for pairwise comparisons. Results: The instrumentation and irrigation techniques had a significant effect on bacterial reduction (p < 0.05). The iRaCe/XPF group showed the strongest effect, followed by the XPS/XPF and XPS/C group, while the iRaCe/C group had the weakest effect. Conclusions: Combining iRaCe with XPF improved its bacterial reduction effect, while combining XPS with XPF did not yield a significant improvement in its ability to reduce bacteria at a depth of $50{\mu}m$ in the dentinal tubules.

• 한국식품영양학회지
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• 제23권2호
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• pp.218-225
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• 2010

본 연구에서는 기능성 식품 소재로서 이용가치가 높은 표고버섯 분말을 스폰지 케이크 제조에 이용하기 위하여 표고버섯 분말을 3, 6, 9, 12%로 첨가한 스폰지 케이크를 제조하여 품질 특성을 파악하고 최적 제품을 생산하고자 하였다. 표고버섯 분말을 첨가한 스폰지 케이크 반죽의 점도, 비중, 수분 함량은 대조군과 표고버섯 분말 첨가군 들 간에는 유의적인 차이를 나타내지 않았다. 표고버섯 분말을 첨가한 스폰지 케이크의 부피 지수는 대조군이 13.75로 가장 낮은 값을 나타냈으며, 표고버섯 분말 3~6% 첨가군에서는 높은 값으로 증가하다가 9~12% 첨가군에서는 감소하는 경향을 보였으나, 표고버섯 분말 첨가군이 대조군보다는 높은 값을 나타내었다. 무게는 대조군과 12%첨가군이 유사한 값을 보였으며, 표고버섯 분말 3% 첨가군에서 가장 높은 값을 나타내었다. Crust 색도 L, a, b는 모두 대조군에 비해 표고버섯 분말 첨가군에서 값이 낮게 나타났고, Crumb 색도 L은 대조군에서 가장 높은 값을 나타내었으며, 표고버섯 분말 첨가량이 증가할수록 낮은 값을 나타내었다. a는 대조군이 가장 높은 값을 나타냈으며, 표고버섯 분말 첨가량이 증가할수록 낮은 값을 나타내었다. b는 대조군과 3% 첨가군간에 유의적인 차이가 있었으며, 6~12% 첨가군 간에는 유의적인 차이가 없었다. 표고버섯 분말을 첨가한 스폰지 케이크의 견고성(hardness)은 대조군과 표고버섯 분말 3% 첨가군에서는 차이가 없었으나, 6% 이상 첨가군에서는 대조군보다 낮은 값을 나타내었다. 파쇄성(fracturability)은 대조군과 표고버섯 분말 3% 첨가군 간에는 유의적인 차이가 없었으나 6% 이상 첨가군에서는 대조군보다 낮은 값을 나타내었다. 부착성(adhesiveness)은 대조군과 표고버섯 분말 첨가군들이 유사한 값을 나타냈으며, 씹힘성(chewiness)은 표고버섯 분말 3% 첨가군에서 가장 높은 값을 나타냈다. 복원성(resilience)은 대조군이 가장 낮은 값을 나타냈으며, 표고버섯 분말 첨가군에서는 유의적인 차이를 나타내었다. 관능검사의 색(color), 향미(flavor), 부드러운 정도(softness), 전체적인 기호도(overall acceptability)는 대조군이 가장 높은 값을 나타내었고, 표고버섯 분말 첨가량이 증가할수록 낮은 값을 나타내었다. 표고버섯 향(Lentinus edodesflavor), 구수한 맛(pleasant taste), 부적합한 향미(off-flavor)는 대조군이 가장 낮은 값을 나타내었고, 표고버섯 분말 첨가량이 증가할수록 증가하는 경향을 보였다. 계란향(egg-flavor), 촉촉함(moistness)은 대조군이 가장 높은 값을 나타내었고, 표고버섯 분말 첨가량이 증가할수록 감소하는 경향을 보였다. 이상의 결과를 종합해 보면 대조군이 기호도 검사에서 가장 높은 점수를 나타내었고, 표고버섯 분말 첨가량이 증가할수록 낮은 점수를 나타내긴 하였지만, 전체적인 품질 특성의 결과를 고려할 때 표고버섯 분말의 3% 첨가가 최적의 배합비로 사료된다.