• 한국전자통신학회논문지
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• 제15권4호
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• pp.665-670
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• 2020

CIGS 박막 태양 전지의 버퍼층은 흡수층과 윈도우층 사이의 밴드정렬(band alignment)을 통해 에너지 변환 효율을 향상시킨다. ZnS는 무독성의 II-VI 반도체 화합물로서 직접천이형 광대역 밴드갭과 n형 전도성을 가지며, 높은 광투과성, 높은 굴절률 등의 우수한 전기적, 광학적 특성을 가지고 있고, 우수한 격자정합을 가지는 물질이다. 이 연구에서, RF 마그네트론 스퍼터링 방법에 의해 증착 후 급속 열처리에 의해 제작된 ZnS 버퍼층 박막의 구조적, 광학적 특성의 상관관계에 대해 고찰하였다. (111), (220), (311) 면의 섬아연광 입방정 구조를 확인할 수 있고, 상대적으로 저온에서 급속열처리를 수행한 시료에서는 (002) 면의 우르쯔광 육방정 구조가 함께 나타나는 다결정이 되었다. 고온에서 급속열처리 수행한 시료에서는 섬아연광 입방정 구조의 단결정으로 상전이 된다. 화학적 성분 분석을 통해서 Zn/S의 비율이 화학양론에 근접한 시료에서 섬아연광 입방정 구조의 단결정이 나타났음을 확인하였다 급속열처리 온도가 증가할수록 흡수단이 다소간 단파장 쪽으로 이동되고, 가시광 파장 범위에서 평균 광투과율이 증가하는 경향성을 보이며 500℃ 조건에서는 80.40%로 향상되었다.

• The Korean Journal of Physiology and Pharmacology
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• 제19권4호
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• pp.365-372
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• 2015

Aripiprazole (ARI) is a commonly prescribed medication used to treat schizophrenia and bipolar disorder. To date, there have been no studies regarding the molecular pathological and immunotoxicological profiling of aripiprazole. Thus, in the present study, we prepared two different formulas of aripiprazole [Free base crystal of aripiprazole (ARPGCB) and cocrystal of aripiprazole (GCB3004)], and explored their effects on the patterns of survival and apoptosis-regulatory proteins under acute toxicity and cytotoxicity test conditions. Furthermore, we also evaluated the modulatory activity of the different formulations on the immunological responses in macrophages primed by various stimulators such as lipopolysaccharide (LPS), pam3CSK, and poly(I:C) via toll-like receptor 4 (TLR4), TLR2, and TLR3 pathways, respectively. In liver, both ARPGCB and GCB3004 produced similar toxicity profiles. In particular, these two formulas exhibited similar phospho-protein profiling of p65/nuclear factor $(NF)-{\kappa}B$, c-Jun/activator protein (AP)-1, ERK, JNK, p38, caspase 3, and bcl-2 in brain. In contrast, the patterns of these phospho-proteins were variable in other tissues. Moreover, these two formulas did not exhibit any cytotoxicity in C6 glioma cells. Finally, the two formulations at available in vivo concentrations did not block nitric oxide (NO) production from activated macrophage-like RAW264.7 cells stimulated with LPS, pam3CSK, or poly(I:C), nor did they alter the morphological changes of the activated macrophages. Taken together, our present work, as a comparative study of two different formulas of aripiprazole, suggests that these two formulas can be used to achieve similar functional activation of brain proteins related to cell survival and apoptosis and immunotoxicological activities of macrophages.

• KSBB Journal
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• 제23권6호
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• pp.513-518
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• 2008

재조합 대장균으로부터 베타-카로틴을 추출/정제하고 정제된 베타-카로틴의 주름개선 성능을 평가하였다. 탈수 용매, 추출 용매에 따른 추출량의 큰 변화는 발견되지 않았으나, wet-cell cake으로부터 추출한 경우가 dry cell로부터 추출한 경우에 비하여 2배 많은 양의 베타-카로틴이 추출되었다. 5 g의 wet-cell cake을 파쇄하고, 아세톤으로 탈수한 후, isobutyl acetate로 추출한 결과 36 mg의 베타-카로틴이 추출되었는데, 이는 61.2% 회수율에 해당한다. 베타-카로틴의 결정을 생성시키고 이를 분리한 결과 순도가 증가하였다. 재조합 대장균 배양액 2.5 L로부터 얻은 wet-cell cake 223 g의 탈수, 세포 파쇄 후 세포 잔사물로부터 베타-카로틴 추출, 농축, 결정화 등을 통하여 최종적으로 순도 93%인 베타-카로틴 결정 633 mg을 얻었다. 사람섬유아세포 배양을 통하여 정제된 베타-카로틴의 세포 독성 및 콜라겐 합성에 미치는 영향을 조사하였다. $1.7{\mu}M$의 베타-카로틴을 첨가 시 세포에 독성을 거의 나타내지 않았으며 콜라겐 합성양은 첨가하지 않은 경우에 비하여 1.4배 증가하였다. 본 결과는 저 유독성 용매를 사용하고 기존보다 간단한 방법을 사용하여 재조합 대장균으로부터 고순도의 베타-카로틴을 정제할 수 있고 이를 기능성 화장품의 주름개선제로 사용될 수 있음을 시사한다.

• Korean Chemical Engineering Research
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• 제55권2호
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• pp.242-246
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• 2017

고온에서 Mn 이온 용출에 의한 성능저하를 보이는 스피넬 결정구조의 $LiMn_2O_4$ 양극 하이브리드 커패시터의 대안으로 열안정성이 높은 올리빈 결정구조의 $LiFePO_4$ 기반 복합양극 소재의 적용가능성을 연구하였다. $LiFePO_4$/활성탄셀을 이용한 1.0~2.3 V의 충 방전을 통한 수명평가에서 상온($25^{\circ}C$) 및 고온($60^{\circ}C$) 조건 모두에서 충 방전 사이클이 진행됨에 따라 음극(활성탄)의 저전압화에 따른 열화로 인한 용량저하 현상이 나타났다. 이의 해결을 위해 50:50 중량비율로 $LiFePO_4/LiMn_2O_4$, $LiFePO_4$/Activated carbon 및 $LiNi_{1/3}Co_{1/3}Mn_{1/3}O_2$ 복합양극을 제조하여 모노셀 충 방전 실험을 수행한 결과, 층상구조의 $LiNi_{1/3}Co_{1/3}Mn_{1/3}O_2$를 사용한 전극이 안정적인 전압거동을 보였다. 또한, 2.3 V 및 $80^{\circ}C$에서 1,000시간 부하를 통한 고온 안정성 실험에서도 $LiNi_{1/3}Co_{1/3}Mn_{1/3}O_2$ 복합양극이 상용 $LiMn_2O_4$ 양극에 비해 약 2배 가량 높은 방전용량 유지율을 보였다.

• 대한치과보철학회지
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• 제53권1호
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• pp.9-18
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• 2015

목적: 본 연구는 Tricalcium phosphate 입자를 사용한 모재분사 후 양극산화처리를 한 임플란트 표면의 특성을 분석하고, 골모유사세포의 반응을 평가하고자 하였다. 재료 및 방법: 직경 10 mm, 두께 3.0 mm 크기의 Grade IV 타이타늄 디스크를 시편으로 사용하였으며, 양극산화처리(ASD)군, 모재 분사 후 양극산화(RBM/ASD)군, 대조군(machined surface)으로 나누어 표면처리하였다. 표면처리 후 FE-SEM, 에너지분산분광기와 주사전자현미경을 사용하여 표면특성을 평가하였다. 세포의 부착을 평가하기 위해 골모유사세포를 이용해 crystal violet assay를 통해 세포부착을 평가하고, 세포 형태는 공초점 레이저 현미경을 사용하여 관찰하였다. 세포증식을 평가하기 위해 XTT 시험을, 세포분화는 역전사 중합효소연쇄반응을 사용하였으며 침착된 칼슘의 양을 측정하기 위해 Alizarin red S stain 을 이용하였다. 비교분석은 one-way ANOVA (SPSS version 18.0)로 유의수준 5%에서 검정하였다. 결과: ASD군과 RBM/ASD군에서, 분화구 모양의 표면 형상이 나타났으며, 대조군과 비교하여 산소와 인산 이온이 관찰되었다. 단위면적당 거칠기는 대조군에서 $0.08{\pm}0.04{\mu}m$, ASD군에서 $0.52{\pm}0.14{\mu}m$, RBM/ASD군에서 $1.45{\pm}0.25{\mu}m$를 보였다. 세포반응실험에서, ASD군과 RBM/ASD군이 대조군에 비해 세포의 부착정도가 높았으며 대조군이 세포증식에서 가장 높은 값을 보였다(P<.05). RT-PCR 실험에서, RBM/ASD군이 다른 군들보다 높은 ALP를 보였다(P<.05). ASD군과 비교했을 때 RBM/ASD군은 세포부착과 증식 정도에서 큰 값을 보였다(P<.05). 결론: 본 연구의 한계내에서 모재분사 후 양극산화 처리한 티타늄 표면 처리 방식이 단순 양극산화 처리한 군이나 대조군보다 골모유사세포의 반응에 효과적인 방법임을 확인하였다.

• BMB Reports
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• 제40권5호
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• pp.773-782
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• 2007

Different isolates of the soil bacterium Bacillus thuringiensis produce multiple crystal (Cry) proteins toxic to a variety of insects, nematodes and protozoans. These insecticidal Cry toxins are known to be active against specific insect orders, being harmless to mammals, birds, amphibians, and reptiles. Due to these characteristics, genes encoding several Cry toxins have been engineered in order to be expressed by a variety of crop plants to control insectpests. The cotton boll weevil, Anthonomus grandis, and the fall armyworm, Spodoptera frugiperda, are the major economically devastating pests of cotton crop in Brazil, causing severe losses, mainly due to their endophytic habit, which results in damages to the cotton boll and floral bud structures. A cry1Ia-type gene, designated cry1Ia12, was isolated and cloned from the Bt S811 strain. Nucleotide sequencing of the cry1Ia12 gene revealed an open reading frame of 2160 bp, encoding a protein of 719 amino acid residues in length, with a predicted molecular mass of 81 kDa. The amino acid sequence of Cry1Ia12 is 99% identical to the known Cry1Ia proteins and differs from them only in one or two amino acid residues positioned along the three domains involved in the insecticidal activity of the toxin. The recombinant Cry1Ia12 protein, corresponding to the cry1Ia12 gene expressed in Escherichia coli cells, showed moderate toxicity towards first instar larvae of both cotton boll weevil and fall armyworm. The highest concentration of the recombinant Cry1Ia12 tested to achieve the maximum toxicities against cotton boll weevil larvae and fall armyworm larvae were 230 ${\mu}g/mL$ and 5 ${\mu}g/mL$, respectively. The herein demonstrated insecticidal activity of the recombinant Cry1Ia12 toxin against cotton boll weevil and fall armyworm larvae opens promising perspectives for the genetic engineering of cotton crop resistant to both these devastating pests in Brazil.

• BMB Reports
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• 제40권5호
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• pp.625-635
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• 2007

The enzyme squalene synthase (EC 2.5.1.21) catalyzes a reductive dimerization of two farnesyl diphosphate (FPP) molecules into squalene, a key precursor for the sterol and triterpene biosynthesis. A full-length cDNA encoding squalene synthase (designated as TcSqS) was isolated from Taxus cuspidata, a kind of important medicinal plants producing potent anti-cancer drug, taxol. The full-length cDNA of TcSqS was 1765 bp and contained a 1230 bp open reading frame (ORF) encoding a polypeptide of 409 amino acids. Bioinformatic analysis revealed that the deduced TcSqS protein had high similarity with other plant squalene synthases and a predicted crystal structure similar to other class I isoprenoid biosynthetic enzymes. Southern blot analysis revealed that there was one copy of TcSqS gene in the genome of T. cuspidata. Semi-quantitative RT-PCR analysis and northern blotting analysis showed that TcSqS expressed constitutively in all tested tissues, with the highest expression in roots. The promoter region of TcSqS was also isolated by genomic walking and analysis showed that several cis-acting elements were present in the promoter region. The results of treatment experiments by different signaling components including methyl-jasmonate, salicylic acid and gibberellin revealed that the TcSqS expression level of treated cells had a prominent diversity to that of control, which was consistent with the prediction results of TcSqS promoter region in the PlantCARE database.

• Applied Microscopy
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• 제16권2호
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• pp.1-13
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• 1986

The purpose of this study was to investigate the morphology and intercellular junctions of the odontoblast of dental pulp in the rat incisor by means of the freeze fracture electron microscopy. Twenty male Sprague-Dawley rats weighing $150{\sim}200g$ were used. After being anesthetized by an intraperitoneal injection of 0.5 ml sodium pentobarbital per kg in body weight(60 mg/ml) the animals were perfused with 2.5% glutaraldehyde-2% paraformaldehyde fixative in 0.1 M cacodylate buffer, pH 7.2 through the ascending aorta for one hour. The incisors were carefully extracted from the jaws and demineralized by suspending them in 0.1 M EDTA in 3% glutaraldehyde (pH 7.2) for two weeks. After demineralization, the specimens were obtained from the portion divided into five equal parts. For freeze-fracture replication, demineralized tissues were infiltrated for several hours with 10%, 25% glycerol in 0.1M cacodylate buffer as a cryoprotectant and then frozen in liquid Freon 22 and stored in liquid nitrogen. Fracturing and replication were done in Balzers BAF 400D high-vacuum freeze-fracture apparatus at $-120^{\circ}C$ under routine $5X10^{-7}$ Torr vacuum. The tissue was immediately replicated with platinum unidirectionally at $45^{\circ}$ angle and reinforced with carbon at $90^{\circ}$ angle unidirectionally or by using a rotary stage. The replication process was monitored by a quartz-crystal device. The replicas were immersed in 100% methanol overnight. The tissue was then digested from the replica by clorox (laundry bleach), placed into 5% EDTA, and washed repeatedly with distilled water. The replicas were picked up on 0.3% formvar-coated 75 mesh grids and examined in the JEOL 100B electron microscope. The results were as follows; 1. Both in thin sections and freeze-fracture replicas, three types of intercellular junctions were recognizable in the plasma membrane of odontoblast: gap junction, tight junction and desmosome-like junction. 2. The nuclear pores were evenly distributed over the nuclear envelope. The pore complex formed a ring about 70 nm in diameter. 3. Gap junctions were found between odontoblasts as well as odontoblasts and neighbouring pulp cells (fibroblast, subodontoblastic cell process, nerve-like fibre). Gap junctions, which were round, ellipsoid and pear-shaped and 600 nm in diameter, were observed in the odontoblast. 4. Numerous round and ellipsoid gap junctions could be frequently seen on the plasma membranes in cell body and apical part of the odontoblasts. On the P face, the junctions were recognized as a cluster of closely packed particles, measuring about 9 nm in diameter, and on the E face, the junctions were recognized as a shallow grooves.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2012년도 제43회 하계 정기 학술대회 초록집
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• pp.254-255
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• 2012

Interest in nano-crystalline silicon (nc-Si) thin films has been growing because of their favorable processing conditions for certain electronic devices. In particular, there has been an increase in the use of nc-Si thin films in photovoltaics for large solar cell panels and in thin film transistors for large flat panel displays. One of the most important material properties for these device applications is the macroscopic charge-carrier mobility. Hydrogenated amorphous silicon (a-Si:H) or nc-Si is a basic material in thin film transistors (TFTs). However, a-Si:H based devices have low carrier mobility and bias instability due to their metastable properties. The large number of trap sites and incomplete hydrogen passivation of a-Si:H film produce limited carrier transport. The basic electrical properties, including the carrier mobility and stability, of nc-Si TFTs might be superior to those of a-Si:H thin film. However, typical nc-Si thin films tend to have mobilities similar to a-Si films, although changes in the processing conditions can enhance the mobility. In polycrystalline silicon (poly-Si) thin films, the performance of the devices is strongly influenced by the boundaries between neighboring crystalline grains. These grain boundaries limit the conductance of macroscopic regions comprised of multiple grains. In much of the work on poly-Si thin films, it was shown that the performance of TFTs was largely determined by the number and location of the grain boundaries within the channel. Hence, efforts were made to reduce the total number of grain boundaries by increasing the average grain size. However, even a small number of grain boundaries can significantly reduce the macroscopic charge carrier mobility. The nano-crystalline or polymorphous-Si development for TFT and solar cells have been employed to compensate for disadvantage inherent to a-Si and micro-crystalline silicon (${\mu}$-Si). Recently, a novel process for deposition of nano-crystralline silicon (nc-Si) thin films at room temperature was developed using neutral beam assisted chemical vapor deposition (NBaCVD) with a neutral particle beam (NPB) source, which controls the energy of incident neutral particles in the range of 1~300 eV in order to enhance the atomic activation and crystalline of thin films at room temperature. In previous our experiments, we verified favorable properties of nc-Si thin films for certain electronic devices. During the formation of the nc-Si thin films by the NBaCVD with various process conditions, NPB energy directly controlled by the reflector bias and effectively increased crystal fraction (~80%) by uniformly distributed nc grains with 3~10 nm size. The more resent work on nc-Si thin film transistors (TFT) was done. We identified the performance of nc-Si TFT active channeal layers. The dependence of the performance of nc-Si TFT on the primary process parameters is explored. Raman, FT-IR and transmission electron microscope (TEM) were used to study the microstructures and the crystalline volume fraction of nc-Si films. The electric properties were investigated on Cr/SiO2/nc-Si metal-oxide-semiconductor (MOS) capacitors.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2010년도 춘계학술대회 초록집
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• pp.75.2-75.2
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• 2010

We studied the fabrication of polycrystalline silicon (pc-Si) films as seed layers for application of pc-Si thin film solar cells, in which amorphous silicon (a-Si) films in a structure of glass/Al/$Al_2O_3$/a-Si are crystallized by the aluminum-induced layer exchange (ALILE) process. The properties of pc-Si films formed by the ALILE process are strongly determined by the oxide layer as well as the various process parameters like annealing temperature, time, etc. In this study, the effects of the oxide film thickness on the crystallization of a-Si in the ALILE process, where the thickness of $Al_2O_3$ layer was varied from 4 to 50 nm. For preparation of the experimental film structure, aluminum (~300 nm thickness) and a-Si (~300 nm thickness) layers were deposited using DC sputtering and PECVD method, respectively, and $Al_2O_3$ layer with the various thicknesses by RF sputtering. The crystallization of a-Si was then carried out by the thermal annealing process using a furnace with the in-situ microscope. The characteristics of the produced pc-Si films were analyzed by optical microscope (OM), scanning electron microscope (SEM), Raman spectrometer, and X-ray diffractometer (XRD). As results, the crystallinity was exponentially decayed with the increase of $Al_2O_3$ thickness and the grain size showed the similar tendency. The maximum pc-Si grain size fabricated by ALILE process was about $45{\mu}m$ at the $Al_2O_3$ layer thickness of 4 nm. The preferential crystal orientation was <111> and more dominant with the thinner $Al_2O_3$ layer. In summary, we obtained a pc-Si film not only with ${\sim}45{\mu}m$ grain size but also with the crystallinity of about 75% at 4 nm $Al_2O_3$ layer thickness by ALILE process with the structure of a glass/Al/$Al_2O_3$/a-Si.