• 한국세라믹학회지
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• 제40권7호
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• pp.657-661
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• 2003

잉크젯 프린터 헤드용 기능성 막으로 많이 활용하고 있는 다층박막(SiO$_2$/poly-Si/SiN/SiO$_2$, 두께, 2.77 $\mu\textrm{m}$)과 다이아몬드 박막(두께, 1.6 $\mu\textrm{m}$)을 미소 외팔보($\mu$-CLB) 형태로 가공한 후 nanoindenter를 이용한 굽힘 시험 방법으로 탄성계수와 굽힘 강도를 측정하였으며 다층막을 이루는 박막 중 SiO$_2$ 박막(두께, 1 $\mu\textrm{m}$)과 SiN 박막(두께, 0.43 $\mu\textrm{m}$)의 탄성계수를 미소 외 팔보 굽힘 시험 방법과 nanoindentation 방법으로 측정한 후 그 결과를 비교하였다. 미소 외팔보 굽힘 시험방법으로 측정한 다층막의 탄성계수와 파괴강도는 외팔보의 폭이 18.5 $\mu\textrm{m}$에서 58.5 $\mu\textrm{m}$로 증가함에 따라 각각 68.08 ㎬과 2.495 ㎬에서 56.53 ㎬과 1.834 ㎬로 감소하였다. SiO$_2$ 박막의 탄성계수 측정값은 외팔보의 폭이 29.6$\mu\textrm{m}$ 와 59.5 $\mu\textrm{m}$ 범위에서 변하여도 영향을 받지 않고 68.16$\pm$0.942 ㎬이었으며, SiN 박막의 탄성계수는 215.45 ㎬이었다. Nanoindentation 방법으로 측정한 SiO$_2$ 박막과 SiN 박막의 탄성계수는 각각 98.78 ㎬, 219.38 ㎬이었다. 이 결과로부터 미소 외팔보 굽힘 시험방법으로 측정한 박막의 탄성계수가 nanoindentation 방법으로 측정한 탄성계수와 2% 미만의 차이를 보이며 일치함을 알 수 있었다.

• 대한소아치과학회지
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• 제29권4호
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• pp.555-560
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• 2002

완전탈구된 치아의 치료법은 재식술을 들 수 있는데, 이는 치조와에서 이탈된 치아를 가능한 빠른 시간 내에 재식립하는 술식이다. 일반적으로 재식술의 성공여부는 치수와 치주인대 손상의 정도, 치아상실 시부터 치조와 내로 재식될 때까지의 경과시간, 탈구된 치아의 보관 상태, 치근의 발육 정도 등에 좌우된다. 그 중 치아상실 시부터 재식까지의 경과시간이 특히 중요한데, 일반적으로 30분 이내에 재식을 시행한 경우에는 90%이상의 성공률을 보인 반면 30분에서 90분 사이에서는 43%, 90분 이상 경과 시에는 7%의 성공률을 보인다고 알려져 있다. 본 증례는 완전탈구 후 오랜 시간이 지연되어 재식을 시행하였으나 치근유착을 통해 비교적 양호한 임상적 결과를 얻었다. 이러한 치료로 결국은 치아의 손실이 일어날지 라도, 이것은 환자 및 보호자의 사고에 따른 충격을 감소시켜주고, 자체로 공간 유지장치로서의 기능을 할 수 있으며, 발치에 따른 치조골의 흡수를 늦추는 한편, 적극적인 보철치료를 위한 시간을 벌어줄 수 있을 것으로 사료된다.

• Membrane and Water Treatment
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• 제11권1호
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• pp.79-85
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• 2020

A single-stage deammonification with a sequencing batch reactor (SBR) that simultaneous nitritation, anaerobic ammonia oxidation (anammox), and denitrification (SNAD) occur in one reactor has been widely applied for sidestream of wastewater treatment plant. For the stable and well-balanced SNAD, a feeding strategy of influent wastewater is one of the most important operating factors in the single-stage deammonification SBR. In this study, single-stage deammonification SBR (working volume 30L) was operated to treat a high-strength ammonium wastewater (1200 mg NH₄⁺-N/L) with different feeding strategies (single feeding and nine-step feeding) under the condition without COD. Each cycle of the step feeding involved 6 sub-cycles consisted of aerobic and anoxic periods for partial nitritation (PN) and anammox, respectively. Contrary to unstable performance in the single feeding, the step feeding showed better deammonification performance (0.565 kg-N/m³/day). Under the condition with COD, however, the nitrogen removal rate (NRR) decreased to 0.403 kg-N/m³/day when the Nine-step feeding strategies had an additional denitrification period before sub-cycles for PN and anammox. The NRR was recovered to 0.518 kg-N/m³/day by introducing an enhanced multiple-step feeding strategy. The strategy had 50 cycles consisted of feed, denitrification, PN, and anammox, instead of repeated sub-cycles for PN and anammox. The multiple-step feeding strategy without sub-cycle showed the most stable and excellent deammonification performance: high nitrogen removal efficiency (98.6%), COD removal rate (0.131 kg-COD/m³/day), and COD removal efficiency (78.8%). This seemed to be caused by that the elimination of the sub-cycles might reduce COD oxidation during aerobic condition but increase the COD utilization for denitrification period. In addition, among various sensor values, the ORP pattern appeared to be applicable to monitor and control each reaction step for deammonification in the multiple-step feeding strategy without sub-cycle. Further study to optimize the number of multiple-step feeding is still needed but these results show that the multiple-step feeding strategy can contribute to a well-balanced SNAD for deammonification when treating high-strength ammonium wastewater with COD in the single-stage deammonification SBR.

• Journal of Yeungnam Medical Science
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• 제19권1호
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• pp.39-48
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• 2002

n-3 불포화지방산이 관절염의 발생 및 경과에 미치는 영향에 대해 알아보고자 Louvain종 흰쥐를 사용하여, 실험군을 정상군과 면역유도 (콜라겐+incomplete Freund's adjuvant)군으로 나누었고, 면역유도군은 다시 대조군 (정상식이) 및 n-3 다불포화지방산군 (식이에 5% n-3 다불포화지방산 함유) 으로 구분하여, 관절염 유도 1 주일전부터 n-3 다불포화지방산이 함유된 식이를 섭취시켰으며 관절염의 발생여부를 x-ray 소견과 광학현미경적 관찰을 통하여 확인하였다. 면역유도 5 주에 대조군의 38%에서 x-ray 소견상 족부종과 광학현미경상 염증소견이 발견되었으나 n-3 다불포화군에서는 이러한 변화가 없었다. 혈당과 혈장 인슐린은 면역유도나 n-3 다불포화지방산 투여에 의한 변화가 없었으나 혈장 중성지방과 콜레스테롤은 n-3 다불포화지방산투여에 의하여 감소하였다. n-3 다불포화지방산의 투여가 콜라젠에 의한 관절염의 발생을 예방 또는 치료할 수 있을 것으로 생각되며 이의 작용기전을 설명하기 위하여 후속 연구가 요망된다.

• Journal of Yeungnam Medical Science
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• 제8권2호
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• pp.95-105
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• 1991

흰쥐 적출소장의 수축성에 미치는 GABA의 영향을 관찰하여 다음과 같은 결과를 얻었다. 1. GABA는 소장을 이완시켰으며 그 이완 작용은 십이지장, 공장 그리고 회장의 순이었다. GABA A수용체 효현제인 muscimol 역시 소장을 이완시켰으며, 그 효능의 강도는 십이지장, 공장 그리고 회장의 순이었다. 그러나 GABA B수용체 효현제인 baclofen은 소장의 운동성에 유의한 영향을 미치지 못하였다. 2. 상경적 GABA A수용체 길항제인 bicuculline과 비 상경적 GABA A수용체 길항제인 picrotoxin은 십이지장에 대한 GABA와 muscimol의 이완 작용을 현저히 억제시켰다. 그리고 bicuculline의 억제 작용이 picrotoxin 보다 강하였다. 3. Sodium channel blocker인 tetrodotoxin은 GABA의 이완 작용을 봉쇄하였다. 4. 신경절 봉쇄적인 hexamethonium은 십이지장에 대한 GABA의 이완작용을 길항하지 못하였다. 이상의 실험 결과로 볼 때 흰쥐 소장의 자발 수축운동에 대한 GABA의 이완작용은 소장이 부위에 따라 다르게 나타나며, 그 작용은 postganglionic presynaptic neuron에 존재하는 GABA A 수용체에 작용함으로써 나타나는 것으로 사료된다.

• Asian-Australasian Journal of Animal Sciences
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• 제22권4호
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• pp.507-515
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• 2009

A series of experiments were conducted to determine the suitable freezing and thawing temperatures for the freezing of boar semen in 5 ml maxi-straws. The ultrastructure, in vitro fertilization (IVF) and artificial insemination (AI) of frozen-thawed semen were also be evaluated. The 5 cm freezing height gave the best results not only in post-thaw motility rate (54.00%), but also in normal acrosome morphology rate (NAR) (80.23%). There was no significant difference in the post-thaw motility between different thawing temperatures and corresponding thawing times (p>0.05); the group of $52^{\circ}C$ and 25 s gave the highest motility rate (45.00%). As a whole, not only from the motility but also the NAR, thawing at $42^{\circ}C$ was better than the other two treatments. In the freezing packages, 5 ml maxi-straw gave a little lower mobility (40%), viability rate (49.58%), plasma membrane integrity rate (53.91%) and NAR (52.65%) than the 0.25 ml straw, but there was no significant difference between the two straw volumes (p>0.05). The IVF capacity of frozen-thawed semen in this experiment was similar to fresh semen. From ultrastructure observation, the main damage to boar spermatozoa after freezing was seen in the acrosome, such as swelling and formation of vesicles. After AI in recipient Shanghai White sows, frozen-thawed semen from 5 ml maxi-straws and pellets produced 72.2% and 80% conception rate and 7.8 and 8 litter sizes, respectively, and there was no significant difference between the 5 ml maxi-straw and the pellet (p>0.05).

• Asian Pacific Journal of Cancer Prevention
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• 제16권14호
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• pp.5773-5777
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• 2015

Background: Oral squamous cell carcinoma (OSCC) is thought to develop from precancerous dysplastic lesions through multistep processes of carcinogenesis involving activation of oncogenes and loss of tumor suppressor genes. The human epidermal growth factor receptor 2 (Her-2/neu [erbB-2]), a cell membrane glycoprotein, is a growth factor receptor that has receptor tyrosine kinase activity. Her2/neu activation plays a central role in cell proliferation and survival. It has been shown that overexpression of Her2/neu increases the rate of cell division and growth, leading to precancerous changes. The aim of the present study was to compare the serum and salivary Her2/neu levels between cases with premalignant and malignant oral lesions. Materials and Methods: Fasting blood samples and unstimulated saliva by passive drooling were collected from three groups of healthy control (n=20), premalignant disorder (PMD) (n=20) and OSCC (n=25) subjects. The HER2 extracellular domain (HER2 ECD) levels were measured using ELISA. Results: The levels of serum Her2/neu showed no significant differences between any of the groups but on the other hand salivary Her2/neu levels were found to be significantly (p<0.05) higher when compared between control (median 68.7 pg/ml, range: 21.5 - 75.8) and OSCC (median 145.6 pg/ml, range: 45.1-191.1). A similar trend was observed when comparing between PMD (median 43.3, range: 22.1 -94.7) and OSCC with a statistical significance of p<0.05. Conclusions: Our study provided evidence of increased salivary Her2/neu in OSCC when compared to PMD and control which was not the case for serum levels. This suggests that probably Her2/neu is not highly amplified as in breast cancer so as to be reflected in serum. Since saliva is in local vicinity of the OSCC, even a mild increase might be mirrored. On the whole, this study proposes Her2/neu as marker for distinguishing premalignant and malignant conditions.

• Asian Pacific Journal of Cancer Prevention
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• 제13권7호
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• pp.3519-3528
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• 2012

Inhibitory effects of Maclura amboinenesis Bl, one plant used traditionally for the treatment of cancers, on metastatic potential of highly metastatic B16F10 melanoma cells were investigated in vitro. Cell proliferation was assessed using the MTT colorimetric assay. Details of metastatic capabilities including invasion, migration and adhesion of B16F10 melanoma cells were examined by Boyden Chamber invasion and migration, scratch motility and cell attachment assays, respectively. The results demonstrated that n-hexane and chloroform extracts exhibited potent anti-proliferative effects (p<0.01), whereas the methanol and aqueous extracts had less pronounced effects after 24 h exposure. Bioactivity-guided chromatographic fractionation of both active n-hexane and chloroform extracts led to the isolation of two main prenylated xanthones and characterization as macluraxanthone and gerontoxanthone-I, respectively, their structures being identified by comparison with the spectral data. Interestingly, both exhibited potent effective effects. At non-toxic effective doses, n-hexane and chloroform extracts (10 and $30{\mu}g/ml$) as well as macluraxanthone and gerontoxanthone-I (3 and $10{\mu}M$) significantly inhibited B16F10 cell invasion, to a greater extent than $10{\mu}m$ doxorubicin, while reducing migration of cancer cells without cellular cytotoxicity. Moreover, exposure of B16F10 melanoma cells to high concentrations of chloroform ($30{\mu}g/ml$) and geratoxanthone-I ($20{\mu}M$) for 24 h resulted in delayed adhesion and retarded colonization. As insights into mechanisms of action, typical morphological changes of apoptotic cells e.g. membrane blebbing, chromatin condensation, nuclear fragmentation, apoptotic bodies and loss of adhesion as well as cell cycle arrest in the G1 phase with increase of sub-G1 cell proportions, detected by Hoechst 33342 staining and flow cytometry were observed, suggesting DNA damage and subsequent apoptotic cell death. Taken together, our findings indicate for the first time that active n-hexane and chloroform extracts as well as macluraxanthone and gerontoxanthone-I isolated from Maclura amboinensis Bl. roots affect multistep of cancer metastasis processes including proliferation, adhesion, invasion and migration, possibly through induction of apoptosis of highly metastatic B16F10 melanoma cells. Based on these data, M. amboinensis Bl. represents a potential candidate novel chemopreventive and/or chemotherapeutic agent. Additionally, they also support its ethno-medicinal usage for cancer prevention and/or chemotherapy.

• Asian Pacific Journal of Cancer Prevention
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• 제15권13호
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• pp.5437-5442
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• 2014

Esophageal squamous cell carcinoma (ESCC) is one of the most malignancies with a poor prognosis. The phospholipase $C{\varepsilon}$ gene (PLCE1) encodes a novel ras-related protein effector mediating the effects of R-Ras on the actin cytoskeleton and membrane protrusion. However, molecular mechanisms pertinent to ESCC are unclear. We therefore designed PLCE1-special small interfering RNA and transfected to esophageal squamous cell (EC) 9706 cells to investigat the effects of PLCE1 gene silencing on the cell cycle and apoptosis of ESCC and indicate its important role in the development of ESCC. Esophageal cancer tissue specimens and normal esophageal mucosa were obtained and assayed by immunohistochemical staining to confirm overexpression of PLCE1 in neoplasias. Fluorescence microscopy was used to examine transfection efficiency, while the result of PLCE1 silencing was examined by reverse transcription (RT-PCR). Flow cytometry and annexin V apoptosis assays were used to assess the cell cycle and apoptosis, respectively. Expression of cyclin D1 and caspase-3 was detected by Western-blotting. The level of PLCE1 protein in esophageal cancer tissue was significantly higher than that in normal tissue. After transfection, the expression of PLCE1 mRNA in EC 9706 was significantly reduced, compared with the control group. Furthermore, flow cytometry results suggested that the PLCE1 gene silencing arrested the cell cycle in the G0/G1 phase; apoptosis was significantly higher than in the negative control group and mock group. PLCE1 gene silencing by RNAi resulted in decreased expression of cyclin D1 and increased expression of caspase-3. Our study suggests that PLCE1 may be an oncogene and play an important role in esophageal carcinogenesis through regulating proteins which control cell cycling and apoptosis.

• Asian Pacific Journal of Cancer Prevention
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• 제14권10호
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• pp.6025-6030
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• 2013

Background: Matrix metalloproteinase-2 (MMP-2) is an enzyme with proteolytic activity against matrix proteins, particularly basement membrane constituents. A single nucleotide polymorphism (SNP) at -1306, which disrupts a Sp1-type promoter site (CCACC box), results in strikingly lower promoter activity with the T allele. In the present study, we investigated whether this MMP-2 genetic polymorphism might be associated with susceptibility to colorectal cancer (CRC) in the Saudi population. We also analyzed MMP-2 gene expression level sin CRC patients and 4 different cancer cell lines. Materials and Methods: TaqMan allele discrimination assays and DNA sequencing techniques were used to investigate the $C^{-1306}T$ SNP in the MMP-2 gene of Saudi colorectal cancer patients and controls. The MMP-2 gene expression level was also determined in 12 colon cancer tissue samples collected from unrelated patients and histologically normal tissues distant from tumor margins. Results and Conclusions: The MMP-2 $C^{-1306}T$ SNP in the promoter region was associated with CRC in our Saudi population and the MMP-2 gene expression level was found to be 10 times higher in CRC patients. The MMP-2 $C^{-1306}T$ SNP is significantly associated with CRC in the Saudi population and this finding suggested that MMP-2 variants might help predict CRC progression risk among Saudis. We propose that analysis of this gene polymorphism could assist in identification of patient subgroups at risk of a poor disease outcome.