• 한국분말재료학회지
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• 제18권2호
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• pp.159-167
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• 2011

The influence of sulfate on the selective catalytic reduction of $NO_x$ on the Ag/$Al_2O_3$ catalyst was studied when $CH_4$ was used as a reducing agent. Various preparation methods influenced differently on the $deNO_x$ activity. Among the methods, cogelation precipitation gave best activity. When sulfates were formed on the surfaces of samples prepared by impregnated and deposition precipitation, $deNO_x$ activity was enhanced as long as suitable forming condition is satisfied. The major sulfate formed in Ag/$Al_2O_3$ catalyst was the aluminum sulfate and it seems that this sulfate acted as a promoter. When Mg was added to the Ag/$Al_2O_3$ catalyst it promoted $deNO_x$ activity at high temperature. Intentionally added sulfate also enhanced $deNO_x$ activity, when their amount was confined less than 3 wt%.

• 한국재료학회지
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• 제15권3호
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• pp.177-182
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• 2005

Large amounts of the waste SiC sludge containing small amounts of Si and organic lubricant were produced during the wire cutting process of the single silicon crystal ingots. The waste SiC sludge was purified by the washing process and the purified SiC powders were used to fabricate continuously porous $SiC-Si_3N_4$ composites using a fibrous monolithic process, in which carbon, $6wt\%\;Y_2O_3-2\;wt\%\;A1_2O_3$ and ethylene vinyl acetate were added as a pore-forming agent, sintering additives, and binder, respectively. In the burning-out process, carbon was fully removed and continuously porous $SiC-Si_3N_4$ composites were successfully fabricated. The green bodies containing SiC, Si particles and sintering additives were nitrided at $1410^{\circ}C$ in a flowing $N_2+10\%\;H_2$ gas mixture. Continuously porous composites were combined with SiC, ${\alpha}Si_3N_4,\;\beta-Si_3N_4$ and a few $\%$ of Fe phases. The pore size of the 2nd and the 3rd passed $SiC-Si_3N_4$ composites was $260\;{\mu}m$ and $35\;{\mu}m$ in diameter, respectively.

• Asian Pacific Journal of Cancer Prevention
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• 제16권18호
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• pp.8177-8186
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• 2016

The present study was aimed at determining the effects of alkylating and oxidative stress inducing agents on a newly identified variant of DNA polymerase beta ($pol{\beta}{\Delta}_{208-304}$) specific for ovarian cancer. $Pol{\beta}{\Delta}_{208-304}$ has a deletion of exons 11-13 which lie in the catalytic part of enzyme. We compared the effect of these chemicals on HeLa cells and HeLa cells stably transfected with this variant cloned into in pcDNAI/neo vector by MTT, colony forming and apoptosis assays. $Pol{\beta}{\Delta}_{208-304}$ cells exhibited greater sensitivity to an alkylating agent and less sensitivity towards $H_2O_2$ and UV when compared with HeLa cells alone. It has been shown that cell death in $Pol{\beta}{\Delta}_{208-304}$ transfected HeLa cells is mediated by the caspase 9 cascade. Exon 11 has nucleotidyl selection activity, while exons 12 and 13 have dNTP selection activity. Hence deletion of this part may affect polymerizing activity although single strand binding and double strand binding activity may remain same. The lack of this part may adversely affect catalytic activity of DNA polymerase beta so that the variant may act as a dominant negative mutant. This would represent clinical significance if translated into a clinical setting because resistance to radiation or chemotherapy during the relapse of the disease could be potentially overcome by this approach.

• 마이크로전자및패키징학회지
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• 제18권4호
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• pp.27-32
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• 2011

Tin(II) acetate와 tin(II) chloride의 주석 precursor를 사용하여 상온에서의 강제 환원 반응으로 주석 나노 입자를 합성시켰다. 0.015 g의 동일한 PVP 양을 첨가한 조건에서 PVP의 분자량이 클수록 비정상적으로 큰 입자들의 생성율이 증가되어 입도 범위가 매우 넓은 주석 나노 입자들이 생성됨을 확인할 수 있었다. 합성된 주석 나노 입자를 함유하는 DEG 용액의 DSC 분석 결과 1차 가열에서는 35 nm 미만 특정 크기 입자들의 수가 충분한 경우에서 DEG의 증발 흡열피크 외에도 특정 크기 입자들의 융점 강하 흡열 피크가 구분되게 검출되었다. 1차 DSC 측정 중 용융된 주석 나노 입자들은 서로 접촉하며 뭉쳐지는 현상이 발생하므로 2차 가열시에는 벌크 주석의 용융 피크에 해당하는 $232^{\circ}C$ 흡열 피크만이 관찰되었다.

• Korean Chemical Engineering Research
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• 제46권2호
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• pp.227-232
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• 2008

화장품용 천연계면활성제를 개발하기 위해 도라지(platycodon grandiflorum) 껍질에서 유기용매를 이용하여 추출물을 얻었다. 도라지 추출물의 화장품용 계면활성을 측정하기 위해 계면장력, 용해도, 기포력, 분산력, 유화력, 유화활성, 유화안정성을 측정하였고 피부자극을 평가하기위해 첩포시험을 실시하였다. 도라지 사포닌 함량이 0.005 wt%일 때 castor oil에 대한 계면장력은 11.5 dyn/cm로 비교대상인 Tween 40이나 quillaja bark보다 낮은 계면활성을 보여주었다. 도라지 추출물은 화장품에 유상으로 사용되는 olive oil, soybean oil, canola oil에 대해서도 우수한 유화활성과 유화안정성을 나타내었다. 2~5%의 도라지 추출물과 글리세린을 사용한 피부자극 시험에서는 도라지 추출물은 약간의 피부자극을 보여 주었다. 결론적으로 도라지 추출물은 화장품용 계면활성력은 양호하나 다소의 피부자극을 보여주었다.

• KSBB Journal
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• 제28권6호
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• pp.356-365
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• 2013

The novel Aloe gels were prepared with dewatering and impregnation by soaking (DIS) processing of Aloe vera leaf slice at four different temperatures (25, 35, 45 and $55^{\circ}C$), using dehydration solution of 40% (w/v) polyethylene glycol (PEG4000). The PEG-impregnation to Aloe vera leaf slice during DIS was observed depending on immersion temperature, and the PEG-impregnated Aloe vera gel (PEG-i-AVG) obtained was characterized using $^1H$ NMR, FT-IR, GPC, XRD and TGA. The PEG-i-AVG had the higher levels of Aloe bioactives (glucomannan and O-acetyl contents) and better quality indices by $^1H$ NMR and FT-IR spectroscopy than those of native Aloe gel. Also, the obtained Aloe gel maintained the bimodal patterns in higher molecular weight region by GPC indicating no degradation of polysaccharide from native Aloe gel. The result observed by SEM confirmed a surface modification by forming the porous structure, and TGA result exhibited better thermal stability than that of native Aloe gel. XRD result revealed that the crystalline structure in Aloe gel was led by incorporation of PEG. Significant decrease of %insolubility and high enhancement of water solubility index were observed, respectively, and highly ordered conformation such as a helix structure was also indicated by Congo red reaction. We concluded that the modification effect for enhancing function of native Aloe gel was successfully obtained by DIS process using PEG as a dehydrating agent. These results suggested that this DIS process had a high potential for developing a new minimally processed product from Aloe vera leaf.

• The Plant Pathology Journal
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• 제25권2호
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• pp.128-135
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• 2009

The survival of Colletotrichum acutatum was investigated in soil, infected fruits, and infected fruit debris incorporated into soil at several temperatures with different soil moisture levels. Samples were examined at 2-week intervals for 18 weeks to determine the survival of the pathogen based on the number of colony forming unit (CFU) of C. acutatum recovered on a semi-selective medium. C. acutatum conidia survived in both sterile and non-sterile soil at 4 and $10^{\circ}C$ for 18 weeks. If infected pepper fruits were completely dried, C. acutatum survived for 18 weeks at temperature from 4 to $20^{\circ}C$. Soil temperature and moisture affected the survival of C. acutatum in infected fruit debris incorporated into soil after air-drying. The effect of soil moisture on survival was weaker at low temperatures than at high temperatures. For up to 16 weeks, conidia were recovered from fruit debris in soil that had been kept at 4 to $20^{\circ}C$ and below 6% soil moisture. Conidia were recovered from fields until approximately 6 months after pepper fruits were harvested. Using PCR with species-specific primers and a pathogenicity test, we identified conidia recovered from soil and infected fruit from both the laboratory and field as C. acutatum and as the primary inoculum causing pepper anthracnose.

• 한국결정성장학회지
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• 제17권5호
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• pp.210-216
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• 2007

극청정 가스필터용 다공성 멤브레인을 제조하기 위해 금속산화물 분말의 in-situ한 환원/소결 공정을 이용하였다. 또한 기공도의 향상을 위해 solid pore forming agent로써 구형의 폴리머 입자를 첨가하여 금속 섬유를 사용한 멤브레인과 비슷한 52%의 기공도를 가지는 니켈 멤브레인을 제조하였다. 제조된 니켈 멤브레인은 폴리머의 첨가에 따라 평균기공크기와 기공도가 증가하였다. 한편 환원/소결 온도가 $800^{\circ}C$에서 $1000^{\circ}C$로 상승함에 따라 평균기공크기와 기공도는 감소하였다. 이는 환원/소결 온도가 상승함에 따라 격자확산 및 입계확산이 진행되어 멤브레인의 수축률 증가를 일으켰기 때문이다.

• 한국세라믹학회지
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• 제49권2호
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• pp.191-196
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• 2012

In this study, tin phosphate glass system($SnO_2-(1-x)P_2O_5-xB_2O_3$) that occur during the melting of the metal oxide inhibition of the oxidation reaction, and to reduce oxides of high melting temperature in the following three methods were melting. The first is the general way in the atmosphere, and the second by injecting $N_2$ gas under a neutral atmosphere, and finally in the air were melted by the addition of a reducing agent Melt in the atmosphere when the oxidation of the metal oxide is inhibited by low temperatures were melting. In addition, the deposition of crystals within glassy or inhibit devitrification phenomenon is also improved over 80% transmittance. This phenomenon, when the melting of glass, many of $Sn^{4+}$ ions are reduced to the $Sn^{2+}$ was forming oxides SnO, because it acts as a modifier oxide.

• Nutrition Research and Practice
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• 제8권1호
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• pp.3-10
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• 2014

The rapid increase in the prevalence of metabolic syndrome, which is associated with a state of elevated systemic oxidative stress and inflammation, is expected to cause future increases in the prevalence of diabetes and cardiovascular diseases. Oxidation of polyunsaturated fatty acids and sugars produces reactive carbonyl species, which, due to their electrophilic nature, react with the nucleophilic sites of certain amino acids. This leads to formation of protein adducts such as advanced glycoxidation/lipoxidation end products (AGEs/ALEs), resulting in cellular dysfunction. Therefore, an effective reactive carbonyl species and AGEs/ALEs sequestering agent may be able to prevent such cellular dysfunction. There is accumulating evidence that histidine containing dipeptides such as carnosine (${\beta}$-alanyl-L-histidine) and anserine (${\beta}$-alanyl-methyl-L-histidine) detoxify cytotoxic reactive carbonyls by forming unreactive adducts and are able to reverse glycated protein. In this review, 1) reaction mechanism of oxidative stress and certain chronic diseases, 2) interrelation between oxidative stress and inflammation, 3) effective reactive carbonyl species and AGEs/ALEs sequestering actions of histidine-dipeptides and their metabolism, 4) effects of carnosinase encoding gene on the effectiveness of histidine-dipeptides, and 5) protective effects of histidine-dipeptides against progression of metabolic syndrome are discussed. Overall, this review highlights the potential beneficial effects of histidine-dipeptides against metabolic syndrome. Randomized controlled human studies may provide essential information regarding whether histidine-dipeptides attenuate metabolic syndrome in humans.