• 공업화학
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• 제31권5호
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• pp.514-519
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• 2020

흑연 소재는 높은 구조적 안정성 및 낮은 가격으로 리튬 이차전지 음극소재로 이용되고 있다. 또한, 탄소 소재의 낮은 속도 특성을 개선하려는 탄소 코팅 연구가 활발히 진행되고 있다. 탄소 코팅은 화학적 반응을 이용하는 CVD 코팅, 용매를 사용하는 습식 코팅, 기계적 충돌에 의한 건식 코팅으로 나뉜다. 본 논문에서는 습식 코팅 공정에서 사용 용매에 따라 탄소 전구체(피치)의 일부만 사용될 수 있는 문제와 용매 제거에 의한 환경 문제를 해결하고자 건식 공정인 고속 분쇄/코팅 공정을 이용하여 리튬 이차전지 음극용 탄소 소재를 제조하였다. 침상 코크스와 피치의 무게비는 8 : 2 wt.%으로 하고, 고속 분쇄/코팅 공정을 이용하여 침상 코크스의 분쇄와 피치의 코팅을 통한 구상화를 진행하였을 때, 침상 코크스의 모서리 면이 피치로 코팅되는 것을 확인하였다. 이 소재를 2400 ℃ 고온 열처리를 진행한 결과 피치 코팅되지 않은 소재와 비교하여 초기용량과 효율은 큰 차이를 보이지 않았으나, 10C/0.1C 속도 특성에서 41.8%의 성능이 향상되었다. 고속 분쇄/코팅 공정을 통해 제조된 소재는 고속 방전용 리튬 이차전지 음극 소재에 사용될 수 있을 것으로 생각된다.

• 한국식품저장유통학회지
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• 제10권2호
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• pp.158-161
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• 2003

10월 초에 채굴한 6년근 수삼을 4$^{\circ}C$$\pm$1$^{\circ}C$, RH 87∼92%에 10주간 저장하면서 1주 간격으로 시료 채취하여 홍삼을 제조하여 당과 색상의 변화를 조사하였다. 총당은 저장기간의경과에 따라 저장전의 62.71%에서 저장 10주째는 54.58%로 약간 감소하였으며 환원당은 저장전 11.69%에서 약간 감소하여 7주째는 9.92%로 조사되었다. 유리당은 fructose는 저장전 0.47%에서 점차 증가하여 10주째는 4.70%로, glucose와 sucrose 는 5주째와 3주째 가장 높은 2.31%와 20.55%를 보인후 점차 감소하였으며, maltose는 저장전 6.62%에서 점차 감소하여 10주째는 1.37%로 조사되었다. 색상은 저장기간의 경과에 따라 전반적으로 증가하여 total color value(ΔE)는 저장전에 비해 9주째가 가장 높은 8.89를 보였다. 색도는 420nm와 440nm의 흡광도가 6주부터 증가하였으며, 갈변전구물질을 조사한 285nm에서도 같은 경향을 보였으나 냉동건조인삼에서는 변화가 관찰되지 않았다.

• Natural Product Sciences
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• 제22권1호
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• pp.46-52
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• 2016

Erectile dysfunction (ED) is a highly prevalent disorder that affects millions of men and considered to be an early symptom of atherosclerosis and a precursor of various systemic vascular disorders. The aim of the present study was to prepare ginsenoside Re enriched fraction (GS-F3K1, ginsenoside Re 10%, w/w) from ginseng berries flesh and to investigate the enhanced activities of GS-F3K1 on alcohol-induced ED. GS-F3K1 was prepared by the continuous liquid and solid separating centrifugation and circulatory ultrafiltration from ginseng berries flesh. GS-F3K1 was administered for 5 weeks in ethanol-induced ED rat by oral administration of 20% ethanol. To investigate the effects of GS-F3K1 on ED model, the levels of nitrite expression, cyclic guanosine monophosphate (cGMP) and erectile response of the penile corpus cavernosum of rat were measured. The erectile response of the corpus cavernosum was restored after GS-F3K1 administration, to a level similar to the normal group. The level of nitrite and cGMP expression in the corpus cavernosum of GS-F3K1-administered male rats was increased significantly compared to positive control group. GS-F3K1 from ginseng berries should effectively restore ethanol-induced ED in male rats and could be developed as a new functional food for the elderly men.

• 한국미생물·생명공학회지
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• 제26권6호
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• pp.537-544
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• 1998

3-HV 몰분율이 증대된 P(3HB-3HV)의 고농도 생산을 위하여 재조합 phbC유전자를 모균주에 재도입시킨 형질전환 Alcaligenes eutrophus AER5의 배양공학적 연구를 수행하였다. 상기 형질전환균주를 전구물질인 valerate가 10.0g/L첨가된 최소배지에서 2단계 배양한 결과 P(3HB-3HV)내의 3-HV 몰분율이 52.2 mol%로 모균주 A. eutrophus H16의 30 mol%에 비해 현저히 증가하였다. 이와 같은 몰분율의 증가는 phbC 유전자의 산물인 PHB synthase의 증폭과 밀접한 관련이 있음을 확인하였다. 2단계 회분배양시 fructose의 보충첨가의 영향을 검토하였으며, 적정농도인 10.0g/L의 fructose를 valerate와 같이 첨가할 경우 총균체량, p(3HB-3HV)의 축적농도, 그리고 축적율은 현저히 증가한 반면, 3-HV 몰분율은 다소 감소하는 경향을 보였다. $Mg^{2+}$ 이온은 P(3HB-3HV) 축적 에 매우 민감한 영향을 미쳤으며, 적정 농도로 판단되는 0.1 g/L일 경우 P(3HB- 3HV) 축적농도는 6.1 g/L, 그리고 3-HV 몰분율은 71.3 %로 현저히 증가하였다. 또한 적정 pH 조절제의 선정을 위하여 NaOH, NaOH와 (NH$_4$)$_2$SO$_4$의 혼합액, 그리고 NH$_4$OH을 비교 검토하였다. 2단계 배양법의 번거로움을 극복하고저 1단계 간헐적 유가식배양법을 검토한 결과, 배양 72시간 후 총균체량 19.2g/L, P(3HB-3HV) 축적농도 10.4 g/L, 그리고 3-HV 몰분율 35 mol%로 2단계 회분 배양법보다 우수한 결과를 얻었다. 이는 형질전환균주를 이용한 3-HV 몰분율이 높은 P(3HB-3HV)의 고농도 생산을 위한 배양조건 확립을 위한 기초자료로 활용될 것이다.90배의 살충력을 보였다. SDS-PAGE와 Western blot 분석에서도 클론 pHLN2-72는 재조합 클론 pHLN2-80(-)보다 약간 높게 ICP가 생성이 되었었다. 이상의 결과는 과다발현에 Plac프로모터와 종결부위가 반드시 필요하며, -72 bp ICP 프로모터가 -80 bp 프로모터보다 과다발현률이 높았으며, ICP 유전자는 반드시 Plac프로모터의 전사 방향에 역방향으로 삽입이 되어야 하는 것으로 나타났다.사용함으로써 고품질의 전통주류 생산이 가능하다고 사료된다.noicacid, methylmalonic acid, 2-methyl-4-keto-pentan-2-ol 등과 지방산의 일종인 tetradecanoic acid, hexadecane, hept-adecanoic acid, octadecanoic acid 등이 확인되었다.er 7.6mm. Further rich management measure and investigation were recommended such as sapling protection, signboard construction, soil erosion controlling and regular monitoring within the community.ldom changed at level 1.will cause students to form the mathematical concepts correctly. 3. By visualizing the process of drawing the quadratic function graph, students understand the quadratic function graph structually. 4. Through the feedback, the recognition ability of the trigonometric function can be improved. 5. It is possible to change

• 한국재료학회지
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• 제12권10호
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• pp.771-775
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• 2002

$Gd_2$$O_3$:Eu phosphor particles with nano-sized and non-aggregation characteristics were prepared by spray pyrolysis using the spray solution containing polymeric precursor and $Li_2$$CO_3$ flux material. Nano-sized $Gd_2$$O_3$:Eu phosphor particles had higher brightness than the commercial $Y_2$$O_3$:Eu phosphor particles. The $Gd_2$$O_3$:Eu phosphor particles had nano-size and non-aggregation characteristics after heat-treatment at $1000^{\circ}C$ when the addition amount of $Li_2$$CO_3$ flux was 1 wt.% and 3 wt.%. The mean size of particles were 200 nm and 400 nm when the amount of flux was 1 wt.% and 3 wt.%, respectively. The prepared phosphor particles had higher photoluminescence intensity than that of the commercial product regardless of the content of$ Li_2$$CO_3$ flux and had the maximum brightness when the content of flux was 5 wt %. The photoluminescence intensity of the nano-sized $Gd_2$$O_3$:Eu phosphor particles containing 3 wt.% $Li_2$$CO_3$ flux was 125% in comparison with that of the micron-sized $Y_2$$O_3$:Eu commercial product.

• Journal of Periodontal and Implant Science
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• 제42권3호
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• pp.95-104
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• 2012

Purpose: The purpose of this study was to determine whether increasing the Ti6Al4V surface oxide negative charge through heat ($600^{\circ}C$) or radiofrequency plasma glow discharge (RFGD) pretreatment, with or without a subsequent coating with fibronectin, stimulated osteoblast gene marker expression in the MC3T3 osteoprogenitor cell line. Methods: Quantitative real-time polymerase chain reaction was used to measure changes over time in the mRNA levels for osteoblast gene markers, including alkaline phosphatase, bone sialoprotein, collagen type I (${\alpha}1$), osteocalcin, osteopontin and parathyroid hormone-related peptide (PTH-rP), and the osteoblast precursor genes Runx2 and osterix. Results: Osteoprogenitors began to differentiate earlier on disks that were pretreated with heat or RFGD. The pretreatments increased gene marker expression in the absence of a fibronectin coating. However, pretreatments increased osteoblast gene expression for fibronectin-coated disks more than uncoated disks, suggesting a surface oxide-mediated specific enhancement of fibronectin's bioactivity. Heat pretreatment had greater effects on the mRNA expression of genes for PTH-rP, alkaline phosphatase and osteocalcin while RFGD pretreatment had greater effects on osteopontin and bone sialoprotein gene expression. Conclusions: The results suggest that heat and RFGD pretreatments of the Ti6Al4V surface oxide stimulated osteoblast differentiation through an enhancement of (a) coated fibronectin's bioactivity and (b) the bioactivities of other serum or matrix proteins. The quantitative differences in the effects of the two pretreatments on osteoblast gene marker expression may have arisen from the unique physico-chemical characteristics of each resultant oxide surface. Therefore, engineering the Ti6Al4V surface oxide to become more negatively charged can be used to accelerate osteoblast differentiation through fibronectin-dependent and independent mechanisms.

• Asian-Australasian Journal of Animal Sciences
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• 제24권5호
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• pp.685-695
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• 2011

Satellite cells are skeletal muscle progenitor/stem cells that reside between the basal lamina and plasma membranes of skeletal fibers in vivo. These cells can give rise to both myogenic and adipogenic cells. Given the possible role for differentiation of satellite cells into adipocytes in marbling and in some pathological disorders like sarcopenia, knowledge of the proteins involved in such process remains obscure. Using two-dimensional polyacrylamide gel electrophoresis coupled with mass spectrometry, we investigated the proteins that are differentially expressed during adipogenic differentiation of satellite cells from bovine longissimus muscle. Our proteome mapping strategy to identify the differentially expressed intracellular proteins during adipogenic differentiation revealed a total of 25 different proteins. The proteins up-regulated during adipogenic differentiation of satellite cells like Cathepsin H precursor, Retinal dehydrogenase 1, Enoyl-CoA hydratase, Ubiquinol-cytochrome-c reductase, T-complex protein 1 subunit beta and ATP synthase D chain were found to be associated with lipid metabolism. The down-regulated proteins like LIM protein, annexin proteins, cofilin-1, Rho GDP-dissociation inhibitor 1 and septin-2, identified in the present study were found to be associated with myogenesis. These results clearly demonstrate that the adipogenic conversion of muscle satellite cells is associated with the up-regulated and down-regulated proteins involved in adipogenesis and myogenesis respectively.

• 산업기술연구
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• 제20권A호
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• pp.247-256
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• 2000

Precursor gels with the composition of $xZrO_2{\cdot}(100-x)SiO_2$ systems (x=10, 20 and 30 mol%) were prepared by the sol-gel method. Kinetic parameters, such as activation energy, Avrami's exponent, n, and dimensionality crystal growth value, m, have been simultaneously calculated from the DTA data using Kissinger and Matusita equations. The crystallite size dependence on tetragonal to monoclinic transformation of $ZrO_2$ was investigated using XRD, in relation to the fracture toughness. The crystallization of tetragonal $ZrO_2$ occurred through 3-dimensional diffusion controlled growth(n=m=2) and the activation energy for crystallization was calculated using Kissinger and Matusita equations, as about $310{\sim}325{\pm}10kJ/mol$. The growth of $t-ZrO_2$, in proportion to the cube of radius, increased with increasing heating temperature and heat-treatment time. It was suggested that the diffusion of Zr4+ions by Ostwald ripening was rate-limiting process for the growth of $t-ZrO_2$ crystallite size. The fracture toughness of $xZrO_2{\cdot}(100-x)SiO_2$ systems glass ceramics increased with increasing crystallite size of $t-ZrO_2$. The fracture toughness of $30ZrO_2{\cdot}70SiO_2$ system glass ceramics heated at $1,100^{\circ}C$ for 5 h was $4.84Mpam^{1/2}$ at a critical crystaliite size of 40 nm.

• 공업화학
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• 제4권3호
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• pp.497-504
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• 1993

본 연구는 고온 구조재료 및 전자재료로 주목받고 있는 복합산화물인 mullite($3Al_2O_3${\cdot}2SiO_2$)를 금속알콕사이드에 의한 졸-겔법으로 합성함에 있어서 재활용품으로서의 aluminium foil을 aluminium 금속원으로 사용하여 알루미늄 알콕사이드를 제조하고 $Si(OC_2H_5)_4$와 혼합하여 가수분해 단계에서 건조조절화학첨가제(Drying Control Chemical Additives, DCCA)를 첨가함으로써 건조시간을 단축시키려는 시도를 하였으며 이러한 DCCA가 mullite 물성에 어떠한 영향을 주는지 검토하고자 하였다. 이때 DCCA로 N, N-dimethyl formamide (DMF), Glycerol, 1, 4-Dioxane과 Oxalic acid가 첨가되었으며 건조된 겔을 각 온도별로 소성하여 TG-DTA, FT-IR, XRD 및 SEM을 사용하여 결정의 전이과정 및 각 소성온도에서의 결정상태 등을 관찰하였다. DCCA를 첨가하여 건조시킨 결과 0.1mole의 DMF를 첨가하였을 경우 DCCA를 첨가하지 않았을 때보다 건조시간이 1/2 정도 단축되었으며 분석결과 mullite의 결정형성에 큰 영향을 미치지 않았음을 확인하였다.

• 원예과학기술지
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• 제31권3호
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• pp.275-281
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• 2013

Low temperature is one of the major environmental factors that affect productivity including reduced growth and budding of vines, and changes of metabolic processes in grape (Vitis spp.). To screen the specific expression of abiotic stress-related genes against cold treatment in 'Kyoho' and 'Campbell Early' grapevines, expression of various defense-related genes was investigated by RT-PCR and real-time PCR. Among the 67 genes analyzed by RT-PCR and real-time PCR, 17 and 16 types of cDNA were up-regulated, while 5 and 6 types were down-regulated in cold-treated 'Kyoho' and 'Campbell Early' grapevines, respectively. Genes encoding carotene (Cart3564 and Cart4472), chalcone isomerase (CHI), cytochrome P450 (CYP), flavonol synthase (FLS), endo-${\beta}$-glucanase precursor (Glu), glutathione peroxidase (GPX), glutathione-S-transferase (GST), leucine-rich repeats (LRR), manganese superoxide dismutase (Mn-SOD), phenylalanine ammonia lyase (PAL), polygalacturonase-inhibiting protein (PGIP), proline rich protein 2 (PRP2), small heat shock protein (sHSP), temperature induced lipocalin (TIL), and thaumatin-like protein (TLP) were up-regulated, while those encoding CBF like transcription factor (CBF1), chitinase-like protein (CLP), cold induced protein (CIP), glycerol-3-phosphate acyltransferase (GPAT), and mitogen-activated protein kinase (MAPK) were down-regulated by low temperature treatment in both in 'Kyoho' and 'Campbell Early'.