• 한국표면공학회:학술대회논문집
• /
• 한국표면공학회 2016년도 추계학술대회 논문집
• /
• pp.199-199
• /
• 2016

Commercially pure titanium (cp-Ti) and Ti alloys (typically Ti-6Al-4V) display excellent corrosion resistance and biocompatibility. Although the chemical composition and topography are considered important, the mechanical properties of the material and the loading conditions in the host have, conventionally. Ti and its alloys are not bioactive. Therefore, they do not chemically bond to the bone, whereas they physically bond with bone tissue. The electrochemical deposition process provides an effective surface for biocompatibility because large surface area can be served to cell proliferation. Electrochemical deposition method is an attractive technique for the deposition of hydroxyapatite (HAp). However, the adhesions of these coatings to the Ti surface needs to be improved for clinical used. Plasma electrolyte oxidation (PEO) enables control in the chemical com position, porous structure, and thickness of the $TiO_2$ layer on Ti surface. In addition, previous studies h ave concluded that the presence of $Ca^{+2}$ and ${PO_4}^{3-}$ ion coating on porous $TiO_2$ surface induced adhesion strength between HAp and Ti surface during electrochemical deposition. Silicon (Si) in particular has been found to be essential for normal bone and cartilage growth and development. Zinc (Zn) plays very important roles in bone formation and immune system regulation, and is also the most abundant trace element in bone. The objective of this work was to study electrochemical characteristcs of Zn and Si coating on Ti-6Al-4V by PEO treatment. The coating process involves two steps: 1) formation of porous $TiO_2$ on Ti-6Al-4V at high potential. A pulsed DC power supply was employed. 2) Electrochemical tests were carried out using potentiodynamic and AC impedance methoeds. The morphology, the chemical composition, and the micro-structure an alysis of the sample were examined using FE-SEM, EDS, and XRD. The enhancements of the HAp forming ability arise from $Si/Zn-TiO_2$ surface, which has formed the reduction of the Si/Zn ions. The promising results successfully demonstrate the immense potential of $Si/Zn-TiO_2$ coatings in dental and biomaterials applications.

• 한국결정성장학회지
• /
• 제9권1호
• /
• pp.39-42
• /
• 1999

N-도핑된 3C-SiC (N-SiC(3C))을 화학기상증착(CVD)으로 $1250^{\circ}C$에서 Si(111) 기판 위에 tetramethylsilane(TMS)를 열분해하여 성장하였다. 수송가스는 $H_{2}$이었고, N-SiC(3C) 에피층은 CVD로 성장되는 동안 $NH_{3}$에 의하여 n-형으로 도핑되었다. N-SiC(3C)의 물리적 특성은 적외선 분광(FTIR), X-선 회절(XRD), 라만 스펙트럼(Raman spectrum), 단면 투과전자영상(XTEM), Hall 측정 및 p/n 다이오드의 전압-진압(I-V) 특성에 의하여 조사되었다. N-도핑된 SiC(3C) 에피층의 전도형은 n-형이었고, 전도형은 $NH_{3}$를 사용한 N-dopant에 의하여 저온에서 잘 조절될 수 있다.

• BMB Reports
• /
• 제43권2호
• /
• pp.97-102
• /
• 2010

Clenbuterol, a $\beta_2$-adrenoceptor agonist, has been proven to be a powerful repartition agent that can decrease fat deposition. Based on results from our previous cDNA microarray experiment of pig clenbuterol administration, a novel up-regulated EST was full-length cloned (4859 bp encoding 1041 amino acids) and found to be the pig homolog of large tumor suppressor 2 (Lats2). We mapped pig Lats2 to chromosome 11p13-14 by using FISH, and western blotting demonstrated that pig Lats2 protein was most abundant in adipose. In Drosophila, Lats2 ortholog was reported as a key component of the Hippo pathway which regulates cell differentiation and growth. Here, we show that pig Lats2 exhibit inverted expression to YAP1, another member of the Hippo pathway which positively regulates cell growth and proliferation, during the differentiation of 3T3-L1 preadipocytes. Our results suggested that Lats2 may involve in Hippo pathway regulating the fat reduction by inhibiting adipocyte differentiation and growth.

• 전기화학회지
• /
• 제5권3호
• /
• pp.143-152
• /
• 2002

Self-assembled monolayer(SAM)로 변형된 금 전극 위로 폴리피롤의 전기화학적 석출 과정을 수용액 상태에서 in-situ EQCM (Electrochemical Quartz Crystal Microbalance)과 ex-situ AFM (Atomic Force Microscopy)을 이용하여 조사하였다. 금 전극에서 cyclic voltammetry로 살펴본 폴리머의 석출은 산화 제한 전위 (anodic limiting potential) 값에 매우 의존적이었으며 주사 횟수에는 의존하지 않았다. 제한 산화 전위가 0.8V (vs Ag | ArCl) 이상일 때 폴리머의 석출은 크게 증가하였다. 그리고 주사 횟수가 증가하면서 질량의 비이상적 변화가 관찰되었는데 이것은 폴리피롤 필름의 rearrangement가 원인이라고 생각된다. 1-dodecanethiol SAM 전극과 thiophene SAM전극에서는 폴리머가 3차원적으로 성장하며 필름의 rearrangement를 수반하였지만 BPUS $(Bis(\omega(N-pyrrolyl)-n-undecyl)disulfide)$ SAM 전극에서는 2차원적인 layer-by-layer 성장을 하고 필름의 rearrangement는 관찰되지 않았다. 폴리머가 급격하게 전극 면으로 석출되면 사슬 모양과 도너츠 모양의 폴리머를 만들며, 정류 상태에 이르면서 주름잡힌 폴리머 필름이 생성되는 것이 원자 힘 현미경 (Atomic Force Microscopy) 이미지로 관찰되었다.

• 한국진공학회:학술대회논문집
• /
• 한국진공학회 2012년도 제42회 동계 정기 학술대회 초록집
• /
• pp.146-147
• /
• 2012

InP 기판위에 자발성장법으로 성장된 InAs 양자점은 $1.55{\mu}m$ 영역에서 발진하는 양자점 반도체 레이저 다이오드 및 광 증폭기를 제작할 수 있기 때문에 많은 관심을 받고 있다. 광통신 대역의 $1.55{\mu}m$ 반도체 레이저 다이오드 및 광 증폭기 분야에서 InAs/InP 양자점이 많은 관심을 받고 있으나, InAs/GaAs 양자점에 비해 제작이 어려운 단점을 가지고 있다. InAs/InP 양자점은 InAs/GaAs 양자점에 비해 격자 불일치가 작아 양자점의 크기가 크고 특히 As 계 박막과 P 계박막의 계면에서 V 족 원소 교환 반응으로 계면 특성 저하가 발생하여 성장이 까다롭다. As 과 P 간의 교환반응은 성장온도와 V/III 에 의해 크게 영향을 받는 것으로 보고되었다. 그러나, P계 InGaAsP 박막 위에 InAs 성장 시 발생하는 As/P 교환반응에 대한 연구는 매우 적다. 본 연구에서는 InGaAsP 박막 위에 InAs 양자점 성장 시 GI (growth interruption)에 의한 As/P 교환반응이 InAs 양자점의 형상 및 광학적 특성에 미치는 영향을 연구하였다. 시료는 수직형 저압 Metal Organic Chemical Vapor Deposition (MOCVD)를 이용하여 $520^{\circ}C$의 온도에서 성장하였다. 그림1(a) 구조의 양자점은 InP (100) 기판위에 InP buffer layer를 성장한 후 InP와 격자상수가 일치하는 $1.1{\mu}m$ 파장의 InGaAsP barrier를 50 nm 성장하였다. 그 후 As 분위기 하에서 다양한 GI 시간을 주었고 그 위에 InAs 양자점을 성장하였다. 양자점 성장 후 InGaAsP barrier를 50 nm, InP capping layer를 50 nm 성장하였다. AFM측정을 위해 InP capping layer 위에 동일한 GI 조건의 InAs/InGaAsP 양자점을 성장하였고 양자점 성장 후 As분위기 하에 온도를 내려주었다. 그림1(b) 구조의 양자점은 그림1(a) 와 모든 조건은 동일하나 InAs 양자점과 InGaAsP barrier 사이에 GaAs 2ML를 삽입한 구조이다. 양자점 형상 특성 평가는 Atomic force microscopy를 이용하였으며, 광특성 분석은 Photoluminescence를 이용하였다.

• 대한예방한의학회지
• /
• 제14권1호
• /
• pp.97-110
• /
• 2010

The wound healing process can be categorized as follows : inflammation, fibroplasia, neovascularization, collagen deposition, epithelialization, and wound contraction. During the healing process, various growth factors are secreted to accelerate wound healing. Previous studies have demonstrated that endogenous growth factors, such as vascular endothelial growth factor(VEGF) are the important regulatory polypeptides for coordinating the healing process. They are released from macrophages, fibroblasts, and keratinocytes at the site of injury and participate in the regulation of reepithelization, granulation tissue formation, collagen synthesis and neovascularization. Onchung-Um has been used clinically to treat various skin diseases. In addition, Onchung-Um has been also used for congestive inflammations. In the present study, we evaluated the effects of Onchung-Um on wound healing process and wound size reduction in rats. Full-thickness skin wounds ($15mm\;{\times}\;15mm$) were created on the back of rats. Rats were then divided into 2 groups : The Onchung-Um treated group that was orally administered with a dose of 193.9mg/100g of Onchung-Um extract per day for 15 days and Control group without Onchung-Um administration. Moreover, the histological changes and VEGF immunoexpressions of two groups were estimated. In results, wound closures were significantly accelerated by oral administration of Onchung-Um extract. Furthermore, in Onchung-Um treated group, there were significant increases in fibroblast migration, epithelialization compared with the Control group. VEGF expressions were also increased in Onchung-Um treated group. This study has therefore demonstrated the Onchung-Um can significantly improve the quality of wound healing and scar formation and the oral administration of Onchung-Um extract may increase early tissue angiogenesis in the incisional wound of an experimental animal model.

• Molecules and Cells
• /
• 제45권9호
• /
• pp.660-672
• /
• 2022

The target of rapamycin complex (TORC) plays a key role in plant cell growth and survival by regulating the gene expression and metabolism according to environmental information. TORC activates transcription, mRNA translation, and anabolic processes under favorable conditions, thereby promoting plant growth and development. Tomato fruit ripening is a complex developmental process promoted by ethylene and specific transcription factors. TORC is known to modulate leaf senescence in tomato. In this study, we investigated the function of TORC in tomato fruit ripening using virus-induced gene silencing (VIGS) of the TORC genes, TOR, lethal with SEC13 protein 8 (LST8), and regulatory-associated protein of TOR (RAPTOR). Quantitative reverse transcription-polymerase chain reaction showed that the expression levels of tomato TORC genes were the highest in the orange stage during fruit development in Micro-Tom tomato. VIGS of these TORC genes using stage 2 tomato accelerated fruit ripening with premature orange/red coloring and decreased fruit growth, when control tobacco rattle virus 2 (TRV2)-myc fruits reached the mature green stage. TORC-deficient fruits showed early accumulation of carotenoid lycopene and reduced cellulose deposition in pericarp cell walls. The early ripening fruits had higher levels of transcripts related to fruit ripening transcription factors, ethylene biosynthesis, carotenoid synthesis, and cell wall modification. Finally, the early ripening phenotype in Micro-Tom tomato was reproduced in the commercial cultivar Moneymaker tomato by VIGS of the TORC genes. Collectively, these results demonstrate that TORC plays an important role in tomato fruit ripening by modulating the transcription of various ripening-related genes.

• 한국표면공학회:학술대회논문집
• /
• 한국표면공학회 2016년도 추계학술대회 논문집
• /
• pp.181-181
• /
• 2016

Hydrogenated microcrystalline silicon (${\mu}c-Si:H$) films have attracted much attention as materials of the bottom-cells in Si thin film tandem photovoltaics due to their low bandgap and excellent stability against light soaking. However, in PECVD, the source gas $SiH_4$ must be highly diluted by $H_2$, which eventually results in low deposition rate. Moreover, it is known that high-rate ${\mu}c-Si:H$ growth is usually accompanied by a large number of dangling-bond (DB) defects in the resulting films, which act as recombination centers for photoexcited carriers, leading to a deterioration in the device performance. During film deposition, Si nanoparticles generated in $SiH_4$ discharges can be incorporated into films, and such incorporation may have effects on film properties depending on the size, structure, and volume fraction of nanoparticles incorporated into films. Here we report experimental results on the effects of nonoparticles incorporation at the different substrate temperature studied using a multi-hollow discharge plasma CVD method in which such incorporation can be significantly suppressed in upstream region by setting the gas flow velocity high enough to drive nanoparticles toward the downstream region. All experiments were performed with the multi-hollow discharge plasma CVD reactor at RT, 100, and $250^{\circ}C$, respectively. The gas flow rate ratio of $SiH_4$ to $H_2$ was 0.997. The total gas pressure P was kept at 2 Torr. The discharge frequency and power were 60 MHz, 180 W, respectively. Crystallinity Xc of resulting films was evaluated using Raman spectra. The defect densities of the films were measured with electron spin resonance (ESR). The defect density of fims deposited in the downstream region (with nonoparticles) is higher defect density than that in the upstream region (without nanoparticles) at low substrate temperature of RT and $100^{\circ}C$. This result indicates that nanoparticle incorporation can change considerably their film properties depending on the substrate temperature.

• Korean Chemical Engineering Research
• /
• 제43권1호
• /
• pp.98-102
• /
• 2005

본 연구에서는 유기금속 전구체인(HFAC)Cu(DMB)을 이용하여 구리를 제조하고, 기판온도 및 요오드 화합물이 증착 구리막의 표면 형상 및 충진 특성에 미치는 영향을 살펴보았다. 증착 온도가 높을수록 표면 형상이 거칠어지고 충진 특성이 악화되었으며, 요오드를 사용하여 증착할 경우 표면 거칠기와 충진 특성이 개선됨을 알 수 있었다. 이때 요오드 화합물과 전구체를 동시에 반응기에 유입할 경우보다 구리의 씨앗층을 증착하고 요오드 화화물을 반응기에 유입한 후 다시 구리 증착을 진행하는 경우가 좀 더 효과가 컸다.

• Asian-Australasian Journal of Animal Sciences
• /
• 제27권12호
• /
• pp.1783-1793
• /
• 2014

Capsaicin is a major constituent of hot chili peppers that influences lipid metabolism in animals. In this study, we explored the effects of capsaicin on adipogenic differentiation of bovine bone marrow mesenchymal stem cells (BMSCs) in a dose- and time-dependent manner. The BMSCs were treated with various concentrations of capsaicin (0, 0.1, 1, 5, and $10{\mu}M$) for 2, 4, and 6 days. Capsaicin suppressed fat deposition significantly during adipogenic differentiation. Peroxisome proliferator-activated receptor gamma, cytosine-cytosine-adenosine-adenosine-thymidine/enhancer binding protein alpha, fatty acid binding protein 4, and stearoyl-CoA desaturase expression decreased after capsaicin treatment. We showed that the number of apoptotic cells increased in dose- and time-dependent manners. Furthermore, we found that capsaicin increased the expression levels of apoptotic genes, such as B-cell lymphoma 2-associated X protein and caspase 3. Overall, capsaicin inhibits fat deposition by triggering apoptosis.