조피볼락, Sebastes sclegeli의 성분화 기간 중 cytochrome P450 aromatase 유전자의 발현

권준영,이찬희 한국발생생물학회 2007 발생과 생식 Vol.11 No.3

자웅이체형 어류의 성결정 및 성분화는 일반적으로 각 개체의 유전형을 따른다. 자연환경에서는 자신이 가진 유전정보의 조절에 따라 성분화 시기에 아로마테이즈 유전자의 발현이 증가하거나 감소하고 그 결과 스테로이드 호르몬들의 조성이 결정되어 각기 다른 방향으로 성분화하는 것으로 알려져 있다. 본 연구에서는 해산 태생어류인 조피볼락(Sebasts schlegeli)의 ovarian type aromatase (P450aromA)와 brain type aromatase (P450aromB)의 유전자를 부분적으로 클로닝하여, 이들의 염기서열을 밝혔으며, 각 유전자에 대한 primer를 제작한 후 성분화 기간 중 이 유전자들의 발현을 조사하였다. 조피볼락 아로마테이즈 유전자들은 조사를 시작한 출산 후 35일째에 여러 개체의 머리와 몸에서 각각 발현되었으나, 52일째에는 아로마테이즈 유전자들의 발현 개체수가 현저히 감소하였다. 그리고 출산 59일째에는 발현개체 수가 다시 증가하였다. P450aromA과 P450aromB의 발현 양상은 전반적으로 유사하였으나, 45일째에는 P450aromB의 발현 개체 수가 P450aromA 발현 개체 수 보다 훨씬 많았다. 조직학적 분석을 통해 제시된 이 종의 성분화 시기는 지금까지 출산 50-65일 전후로 알려져 왔으나, 본 연구에서 나타난 아로마테이즈 유전자들의 발현 결과를 볼 때, 이 종의 실질적인 성분화는 알려진 것보다 최소한 1-2주 정도 빨리 진행될 가능성이 있다. 본 연구의 결과는 또한 태생어류의 성분화도 난생어류의 성분화에서 보고된 것과 마찬가지로 아로마테이즈의 작용과 밀접하게 연관되어 있다는 사실을 시사한다.

Responses of HSP Gene Expressions to Elevated Water Temperature in the Nile tilapia Oreochromis niloticus

권준영,김주영 한국발생생물학회 2010 발생과 생식 Vol.14 No.3

Water temperature influences on various key biological events in fish, but the internal pathway of the temperature effects are not well understood. Heat shock proteins (HSPs), known to respond in the level of cells to many environmental factors including temperature, could improve our understanding on the pathway. Some biological processes such as gonadal development and sex differentiation in the Nile tilapia Oreochromis niloticus is particularly sensitive to water temperature. In this study, we have investigated the expressions of HSP70 and HSP90 genes in young tilapia at an ordinary temperature (28℃) and elevated water temperature (36℃). The distribution of the expressions of HSP70 and HSP90 mRNA in this species were found to be almost ubiquitous, being detected in all tissues studied here (brain, gonad, liver and muscle), suggesting the house keeping functions of these genes. Heat shock by elevating temperature from 28℃ to 36℃ significantly increased the expression of HSP70 mRNA in the gonad, liver and muscle for several hours (P<0.05) (brain tissue was not examined for this). The increased level of HSP70 gene expression recovered to the level at control temperature (28℃) when fish were kept continuously at high temperature (36℃) for 24 hours. Contrary to this, expression of HSP90 mRNA did not show significant increase in the gonad and muscle by the same heat shock (P>0.05), except in the liver where the expression of HSP90 mRNA increased continuously for 24 hours at 36℃. The results obtained in this study suggest that response to temperature change in different tissue or organ may utilize different heat shock proteins, and that HSP70 may have some importance in temperature-sensitive gonadal event in the Nile tilapia.

Synthesis and Analysis of Amide-based High Heat-resistant Polyimides

권준영,이승우 한국고분자학회 2021 한국고분자학회 학술대회 연구논문 초록집 Vol.46 No.2

With the development of advanced technology, it was intended to make high-strength heat-resistant polyimide for future military power. In this study, an effort was made to make polyimide that satisfies a 95% decomposition temperature of 400 ℃ or higher and a tensile strength of 80 Mpa or higher. The structures of the resulting compounds and polyimides were analyzed by ¹H-NMR (proton nuclear magnetic resonance spectroscopy), Fourier transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA) and UTM. Amide-type AA1 and AA2 showed thermal stability of 410~421 °C under the influence of the cyclohexyl group contained in the monomer, and sufficiently achieved over 400 ℃ when the Td was 95%. Although the mechanical properties of the amide system showed some differences depending on the type of dianhydride used together with diamine, the tensile strength was 86~87 Mpa, and the target 80 Mpa or higher was easily achieved. All of the goals set were achieved.

Synthesis and Characteristic Analysis of Polyimide, Which Contains Aliphatic Benzoxazole Monomers To Make High Heat Resistance

권준영,이승우 한국고분자학회 2022 한국고분자학회 학술대회 연구논문 초록집 Vol.47 No.1

Synthesis and Analysis of Polyimide with Increased Physical Properties Using APTMS and TEOS

권준영,이승우,이유정 한국고분자학회 2021 한국고분자학회 학술대회 연구논문 초록집 Vol.46 No.1

Most of aromatic polyimide has excellent physical properties, but it has a dark brown color making it difficult to apply to a display field requiring colorless and transparent optical properties. In this study, a transparent polyimide with good physical properties was prepared by the thermal imidization to solve this problem. To improve the physical properties, it was added TEOS or APTMS to 4,4'-(Hexafluoroisopropylidene) diphthalic anhydride (6FDA) and TFMB to create a crosslinked structure using a sol-gel process. The structure of the resulting polyimide was analyzed by fourier transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA) and UTM. It was found that the tensile strength of the polyimide polymer made by adding water to 6FDA, TFMB, and APTMS increased as the content of water increased, that is, as the APTMS content decreased and the TEOS content decreased.

레이저를 이용한 결정질 실리콘 태양전지의 Double Texturing 제조 및 특성

권준영,한규민,최성진,송희은,유진수,유권종,김남수,Kwon, Jun-Young,Han, Kyu-Min,Choi, Sung-Jin,Song, Hee-Eun,Yoo, Jin-Soo,Yoo, Kwon-Jong,Kim, Nam-Soo 한국재료학회 2010 한국재료학회지 Vol.20 No.12

In this paper, double texturization of multi crystalline silicon solar cells was studied with laser and reactive ion etching (RIE). In the case of multi crystalline silicon wafers, chemical etching has problems in producing a uniform surface texture. Thus various etching methods such as laser and dry texturization have been studied for multi crystalline silicon wafers. In this study, laser texturization with an Nd:$YVO_4$ green laser was performed first to get the proper hole spacing and $300{\mu}m$ was found to be the most proper value. Laser texturization on crystalline silicon wafers was followed by damage removal in acid solution and RIE to achieve double texturization. This study showed that double texturization on multi crystalline silicon wafers with laser firing and RIE resulted in lower reflectance, higher quantum yield and better efficiency than that process without RIE. However, RIE formed sharp structures on the silicon wafer surfaces, which resulted in 0.8% decrease of fill factor at solar cell characterization. While chemical etching makes it difficult to obtain a uniform surface texture for multi crystalline silicon solar cells, the process of double texturization with laser and RIE yields a uniform surface structure, diminished reflectance, and improved efficiency. This finding lays the foundation for the study of low-cost, high efficiency multi crystalline silicon solar cells.

Synthesis and Analysis Polyimide Including Benzoxazole Monomer

권준영,이승우 한국고분자학회 2023 한국고분자학회 학술대회 연구논문 초록집 Vol.48 No.1

새로운 가치를 창조하는 부동산 투자의 미래

권준영 한국부동산분석학회 2019 부동산분석학회 학술발표논문집 Vol.2019 No.1

Micro electrical discharge drilling characteristics of conductive SiC–Ti 2 CN composite

권준영,장성훈,권원태,김욱영 대한기계학회 2018 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.32 No.7

An electrically conductive SiC-Ti 2 CN composite was fabricated from β-SiC and TiN powders with 2 vol% equimolar Y 2 O 3 -Sc 2 O 3 additives by conventional hot-pressing. The composite (electrical resistivity of nearly 10 -4 Ω·cm) was wire electro discharge machined into a specimen having a thickness of 500 μm. Entrance clearance, machining time, number of shorts, material removal rate (MRR), counts, and the effects of the capacitance and voltage of conductive SiC-Ti 2 CN composite during micro electrical discharge drilling were measured and compared to those of SUS304. As the unit discharge energy increased, entrance clearance, machining time, and number of shorts decreased. A decrement in the number of shorts was the main reason for decrements in entrance clearance and machining time. MRR was proportional to unit discharge energy. The study to determine the location of shorts during electro discharge drilling was also conducted. It was founded that the short circuit occurred mainly at the beginning (0–1000 cts) because of low electrical density, and right before the exit (3000–5000 cts) owing to the difficulty of removing debris. Both the capacitance and voltage tended to be inversely proportional to the number of shorts.

The Effect of Day Length and Lunar Phases on the Spawning Activity in the Nile Tilapia Oreochromis niloticus

권준영,김정현,김보경 한국발생생물학회 2010 발생과 생식 Vol.14 No.1

Nile tilapia (Oreochromis niloticus) are mouth-brooders so that the females holding eggs in their mouth sacrifice their somatic growth for reproduction. For this reason, artificial control of reproduction for the culture of this species has been of interest. Manipulation of photoperiod is an emerging technique for such purpose, but little information is available to establish appropriate photoperiod regime. To obtain necessary basic information, sexually mature females were individually accommodated to glass aquarium, and monitored the spawning activity for two years under natural photoperiod regime. Female tilapia spawned most frequently on March, April and May when the day length gradually increased from 11 hours to 14 hours and least frequently on September, October, November and December when the day length gradually decreased from 13 hours to less than 10 hours in the first year. The decrease of spawning frequency as day length decreased was also observed in the second year, although the increase of spawning frequency as day length increased was less clear. Spawning of female tilapia was less active when the night was dark due to the disappearance of moonlight (Dark Phase), compared to the Phase of Getting Lighter, Light Phase and Phase of Getting Darker. Results from this study suggest that long day length, particularly increasing phase, is favoured for active spawning of Nile tilapia, and that this species, as a tropical fish species, may utilize changing lunar phases as a secondary environmental cue for reproduction.