• 멤브레인
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• 제20권1호
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• pp.55-61
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• 2010

원자전달 라디칼 중합을 이용하여 polystyrene-b-poly(oxyethylene methacrylate) (PS-b-POEM) 블록 공중합체를 합성하고, FT-IR을 통해 중합이 성공적으로 이루어졌음을 확인하였다. 또한 자기 조립된 블록 공중합체 막을 제조한 후, 전구체 $AgCF_3SO_3$ 도입과 UV 조사를 통해 고체상에서 은 나노입자를 성장시켰다. TEM 전자현미경과 UV-visible 분광학 분석을 통해 블록 공중합체 막의 내부에 은 나노입자가 형성된 것을 확인하였고, 또한 친수성 POEM 영역의 함량을 조절함으로써 나노입자의 크기를 조절할 수 있었다. 금속 나노입자를 제조하는 데 있어서 POEM 함량이 적은 블록 공중합체가 더 효과적임을 확인하였다.

• 한국전기전자재료학회논문지
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• 제17권1호
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• pp.7-15
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• 2004

The ferroelectric SBT thin films as a material of capacitors for non-volatile FRAMs have some problems that its remanent polarization value is relatively low and the crystallization temperature is quite high abovc 80$0^{\circ}C$. Therefore, in this paper, SBTN solution with S $r_{0.9}$B $i_{2.1}$T $a_{1.8}$N $b_{0.2}$$O_{9}$ composition was synthesized by sol-gel method. Sr(O $C_2$ $H_{5}$)$_2$, Bi(TMHD)$_3$, Ta(O $C_2$ $H_{5}$)$_{5}$and Nb(O $C_2$ $H_{5}$)$_{5}$ were used as precursors, which were dissolved in 2-methoxyethanol. SBTN thin films with 200 nm thickness were deposited on Pt/Ti $O_2$/ $SiO_2$/Si substrates by spin-coating. UV-irradiation in a power of 200 W for 10 min and rapid thermal annealing in a 5-Torr-oxygen ambient at 76$0^{\circ}C$ for 60 sec were used to promote crystallization. The films were well crystallized and fine-grained after annealing at $650^{\circ}C$ in oxygen ambient. The electrical characteristics of 2Pr=11.94 $\mu$C/$\textrm{cm}^2$, Ps＋/Pr＋=0.54 at the applied voltage of 5 V were obtained for a 200-nm-thick SBTN films. This results show that 2Pr values of the UV irradiated and rapid thermal annealed SBTN thin films at the applied voltage of 5 V were about 57% higher than those of no additional processed SBTN thin films. thin films.lms.s.s.

• 한국세라믹학회지
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• 제55권1호
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• pp.55-60
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• 2018

In this study, quantum dots composed of $Mn^{2+}$ doped ZnS core and ZnS shell were synthesized using MPA precursor at room temperature. The ZnS: Mn/ZnS quantum dots were prepared by varying the content of MPA in the synthesis of ZnS shells. XRD, Photo-Luminescence (PL), XPS and TEM were used to characterize the properties of the ZnS: Mn/ZnS quantum dots. As a result of PL measurement using UV excitation light at 365 nm, the PL intensity was found to greatly increase when MPA was added at 15 ml, compared to the case with no MPA; the PL peaks shifted from 603 nm to 598 nm. A UV sensor was fabricated by using a sputtering process to form a Pt pattern and placing a QD on the Pt pattern. To verify the characteristics of the sensor, we measured the electrical properties via irradiation with UV, Red, Green, and Blue light. As a result, there were no reactions for the R, G, and B light, but an energy of 3.39 eV was produced with UV light irradiation. For the sensor using ZnS: Mn/ZnS quantum dots, the maximum current (A) value decreased from $4.00{\times}10^{-11}$ A to $2.62{\times}10^{-12}$ A with increasing of the MPA content. As the MPA content increases, the PL intensity improves but the electrical current value dropped because of the electron confinement effect of the core-shell.

• 한국미생물·생명공학회지
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• 제47권3호
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• pp.381-389
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• 2019

Chlorella vulgaris was isolated from the Nile River, Qalubia Governorate, Egypt, for possible use in biodiesel production. BG-II nutrient growth media was used for isolation and laboratory growth. Identification was performed via 18S rRNA gene amplification, followed by sequencing. The alga was exposed to UV-C (254 nm) for 15, 30, and 45 s to improve dry weight accumulation and to increase the oil production. Daily measurements of dry weight ($g{\cdot}l^{-1}$) were performed; oil content and volumetric lipid productivity were also determined. UV-C exposure led to an increase in the volumetric lipid productivity by 27, 27.3, and $32.4mg{\cdot}l^{-1}{\cdot}d^{-1}$ with 15, 30, and 45 s, respectively, as compared with the control, which resulted in $18mg{\cdot}l^{-1}{\cdot}d^{-1}$. Of the examined mutants, the one with the highest productivity was re-irradiated by UV-C (254 nm) for 15, 30, 45, and 60 s. For 15 s of exposure time, the oil content increased to 34%, while it was 31% at 30 s; further, it decreased to 22% at 45 and 60 s exposures. The fatty acid methyl ester profile was 82.22% in the first mutant at 45 s, compared with the wild strain that contained a total of 66.01% of FAs. Furthermore, the highest levels of polyunsaturated fatty acid methyl ester were observed in the mutant exposed for 45 s, and it reached 11.41%, which reduced the cetane number to 71.3.

• 미생물학회지
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• 제24권3호
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• pp.221-227
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• 1986

Aspergillus nidulans에서, UV나 4- NQO에 의한 돌연변이 유발에 있어 성내적으로 핑요한 uvsH돌연변이를 가 지고 있는 변이주를 이용하여 mitotic recombination 현상을 조사하였다. 비록 uvsH locus는 {pB 37과 centromere 사이에서의 자말적인 mitotic crossing over에는 영향플 주지 않았지만 uvsH/uvsH동형이애체에서 UV에 의한 Int te rgenic recombination은 얻어나지 않았다. 또한 서로 상보적이 아닌 riboA 1과 ribo A3 유전핵적 단시에서의 riboflavin에 대한 gene converSlOn에 있어셔 u uvsH 돌연변이는 자말석이든 LV보 유멜시켰던 이 과정에 관여하고 있지 않있다. 비록 정상석인 성 장에서는 거으1 차이가 없였지만, 세포들을 UV로 조사하였을 때 야생주에 비해 uvsH동형 이배체에서의 aneuploid발생이 높은 빈도로 나타났다.

• Bulletin of the Korean Chemical Society
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• 제31권2호
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• pp.351-354
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• 2010

Nickel nanoparticles (Ni NPs) appeared to exhibit the catalytic activity in one-pot cyclocondensation reaction for the preparation of 3,4-dihydropyrimidine-2(1H)-ones via Biginelli reaction from aromatic/heteroaromatic/aliphatic aldehydes, urea/thiourea and ethyl acetoacetate under microwave irradiation has been described. The UV absorbance spectra showed metallic Ni characteristics and appreciate with the particle size determined by Transmission electron microscopy (TEM). After reaction course the Ni NPs can be re-covered and reused without any apparent loss of activity.

• Nutrition Research and Practice
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• 제17권4호
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• pp.641-659
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• 2023

BACKGROUND/OBJECTIVES: The skin is the outermost organ of the human body and plays a protective role against external environmental damages, such as sunlight and pollution, which affect anti-oxidant defenses and skin inflammation, resulting in erythema or skin reddening, immunosuppression, and epidermal DNA damage. MATERIALS/METHODS: The present study aimed to investigate the potential protective effects of red orange complex H extract (ROC) against ultraviolet (UV)-induced skin photoaging in Skh:HR-2 mice. ROC was orally administered at doses of 20, 40, and 80 mg/kg/day for 13 weeks, along with UV irradiation of the mice for 10 weeks. RESULTS: ROC improved UV-induced skin barrier parameters, including erythema, melanin production, transepidermal water loss, elasticity, and wrinkle formation. Notably, ROC inhibited the mRNA expression of pro-inflammatory cytokines (interleukin 6 and tumor necrosis factor α) and melanogenesis. In addition, ROC recovered the UV-induced decrease in the hyaluronic acid and collagen levels by enhancing genes expression. Furthermore, ROC significantly downregulated the protein and mRNA expression of matrix metalloproteinases responsible for collagen degradation. These protective effects of ROC against photoaging are associated with the suppression of UV-induced phosphorylation of c-Jun NH2-terminal kinase and activator protein 1 activation. CONCLUSIONS: Altogether, our findings suggest that the oral administration of ROC exerts potential protective activities against photoaging in UV-irradiated hairless mice.

• 대한수의학회지
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• 제45권1호
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• pp.1-6
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• 2005

In this study we assessed the influences of ultraviolet (UV) light B radiation on epidermal cells by apoptotic sunburn cell (SBC) and the effect of green tea treatment on the inhibition of SBC formation in SKH1-hr mouse. The extent of changes following $200mJ/cm^2$ (0.5 mW/sec) was studied at 0, 3, 6, 12, 18, 24, 30 or 36 hours after exposure. SBCs were recognized by 3 hours after irradiation. There was tendency to increase from 3 hours to 24 hours and decrease from then to 36 hours after irradiation. The mice that received 0, 25, 50, 100, 200, 400 or $800mJ/cm^2$ of UVB were examined 24 hours after irradiation. The SBCs were induced as the radiation dose increases from 0 to $200mJ/cm^2$. A further increase of radiation dose has little further effect. The frequency of UVB ($200mJ/cm^2$)-induced SBC formation was reduced by intraperitoneal injection of green tea extract (p<0.01).

• 한국미생물·생명공학회지
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• 제7권3호
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• pp.165-173
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• 1979

자연선조사한 대장균B주의 세포분열회복활성분을 구명코저 자외선내성균인 대장균 B/r 주의 초음파추출액으로부터 활성성분分을 분리한 결과 $\beta$-NAD가 관여함이 발표되었다. 본고에서는$\beta$-NAD 이외 Magnesium이 활성물질의 안정화가 중요한 역할을 나타냄을 구명하였으며 10~30%의 서당밀 도구배원심분리에 의해 2 개의 새로운 활성부분이 있음을 확인하였다. 2 개의 활성물질 가운데 하나는 원심관의 최하부에 위치하였으며 또 다른 하나는 상부의 분자량 45,000 부위에서 회수되었다. 하부에 위치한 활성획분은 Mg++이 그 활성에 무관하였으나 상부의 저분자 활성부분은 $Mg^{++}$을 첨가하지 않으면 회수가 불가능하였다. 저분자활성부분은 pronase에 대해 감수성이었으며 DNA-ligase 는 아님이 추정되었다. 초원심분리과정에 $N_2$ gas를 처리할 경우 aeration에 비해 약 2 배의 활성이 나타났다. $Mg^{++}$은 $\beta$-NAD에 또하나의 회복활성 및 필수적인자로 요구된다고 생각된다.

• 한국의류학회지
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• 제21권5호
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• pp.903-910
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• 1997

Vit. D3 was measured which was produced by UVB irradiation to provit. D3, 7-d ehyd rock o 1 cst or of (7-DH Cl Measuring the amount of vie. D3 when it was irradiated to the fabrics which had different UV8 transmittance, production of vile. Ds by UVB(Ultraviolet B) and inhibition from formation of vile. D3 by fabrics were absorbed and followings are the results. As the amount of irradiated compared UVB increased, the amount of the production of vile. D3 produced by UVB irradiation from 7-DHC was increased. After treatment of 7-DHC by UVB irradiation and incubated respectively for 24hr, 48hr and 72hr at 36.5$^{\circ}C$ The amount of lit. D3 was increased as incubating time passed. When irradiated UVB on 7-DHC, intermediate of vile. D3, lumisterol, tachysterol and previt. D were showed and those materials were seemed to be changed to vile. D3 as incubation time passed. The amount of vile. D3 which was produced by irradiation 7-DHC showed close relation with UVB transmittance rate of summer fabrics (r= 0.987). Clothes, hats, and sun screen cream reduce the amount of vile. D3 Produced naturally in human skin and it result the decrease of calcium in blood which is absorbed through vit. D. Those all can cause or worsen osteomalacia especially to women and the aged people. Therefore, it is necessary to research and to develop function oriented clothing which can transmit UV which produce vile. D3 at the same time which can protect toxical UVB.