• 천문학회보
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• 제43권1호
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• pp.43.2-44
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• 2018

One of the keys to interpreting the characteristics and evolution of interstellar medium in the Milky Way is to understand the distribution of hot gas ($10^5-10^6K$). Gases in this phase are difficult to observe because they are in low density and lack of easily observable tracers. Hot gases are observed mainly in the emission of the FUV ($912-1800{\AA}$), EUV ($80-912{\AA}$), and X-rays (T> $10^6K$) of which attenuation is very high. Of these, FUV emission lines originated from high-stage ions such as O VI and C IV can be the most effective tracers of hot gases. To determine the spatial distribution of O VI and C IV emissions, we have analyzed the spectra obtained from FIMS (Far-ultraviolet IMaging Spectrograph), which covers about 80 percent of the sky. The hot gas volume filling factor, which varies widely from 0.1 to 0.9 depending on the supernova explosion frequency and the evolution model, has been calculated from the O VI and C IV maps. The hot gas generation models has been verified from the global distribution of O VI and C IV emissions, and a new complementary model has been proposed in this study.

• Bulletin of the Korean Chemical Society
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• 제1권1호
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• pp.35-39
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• 1980

A vacuum ultraviolet photolysis of ethyl bromide was studied in the pressure range of 0.5-19.9 torr and at 123.6 nm krypton resonance line. The pressure effect on the reaction was studied by increasing the reactant pressure and by adding an inert gas, e.g., He. In the observation the monatomic gas is found to be no effect in the reaction. A scavenger effect of the reaction was also performed by adding NO gas as a radical scavenger and was found to be quite efficient to scavenge a radical product $C_2H_6$. The observation of the major reaction product $C_2H_6$ was interpreted in terms of a molecular elimination. Nontheless the decreasing phenomenon of ${\phi}_{C_2H_4}/{\phi}_{C_2H_6}$ with pressure rise was attributed to the existence of the two electronically excited states. One state proceeds to the molecular elimination and the other to carbon-bromine bond fission. The excitation and the decomposition mechanisms between two excited states and the reaction products were interpreted in terms of the first excitation which proceeds the molecular elimination, and the second excitation which resulted from the first excited state by collisional cross over decomposes by carbon-bromine bond fission.

• 한국식품영양과학회지
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• 제40권2호
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• pp.245-252
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• 2011

신선 채소 중 레드 치커리와 청경채의 미생물학적 안전성 확보를 위해 50 ppm 이산화염소수와 10 kJ/$m^2$ UV-C 조사 병합 처리에 따른 저장 중 미생물 수 및 품질 변화에 미치는 영향을 처리 후 $4{\pm}1^{\circ}C$에서 7일 동안 저장하면서 실험하였다. 레드 치커리와 청경채의 총 호기성 세균 수는 대조구와 비교 시, 이산화염소수와 UV-C 병합 처리구에서 2.64, 2.55 log CFU/g 감소시켰으며, 효모 및 곰팡이는 2.41, 2.00 log CFU/g 감소시켰다. 또한, 레드 치커리와 청경채의 저장 7일 후, 이산화염소수와 UV-C 병합 처리구의 총 호기성 세균수는 3.71, 3.93 log CFU/g으로 대조구와 비교할 때, 2.60, 2.69 log CFU/g의 유의적인(p<0.05) 차이를 나타냈다. 병합 처리는 대조구와 비교하여 레드 치커리와 청경채의 저장 중 Hunter 색도 값에 부정적인 영향을 끼치지 않았다. 관능검사에 있어서도 병합 처리구가 대조구보다 저장 중 관능적 품질 유지에도 효과가 있는 것으로 나타났다. 따라서 본 연구결과, 50 ppm 이산화염소수와 10 kJ/$m^2$ UV-C 조사의 병합 처리가 레드 치커리와 청경채의 저장 중에 오염될 수 있는 위해미생물의 감소와 외관적 품질유지에 효과적인 처리 기술이라고 판단된다.

• Biomolecules & Therapeutics
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• 제19권3호
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• pp.308-314
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• 2011

It has been shown that circadian genes not only play an important role on circadian rhythms, but also participate in other physiological and pathological activities, such as drug dependence, cancer development and radiation injury. The Per2, an indispensable component of the circadian clock, not only modulates circadian oscillations, but also regulates organic function. In the present study, we applied mPER2-upregulated NIH3T3 cells to reveal the relationship of mPer2 and the cells damaged by ultraviolet C (UVC). NIH3T3 cells at the peak of the expression of mPer2 induced by phorbol 12-myristate 13-acetate (PMA) demonstrated little damage by UVC evaluated by MTT assay, cell growth curves and cell colony-forming assay, compared with that at the nadir of the expression of mPer2. Overexpression of mPER2, accompanied p53 upregulated, also demonstrated protective effect on NIH3T3 cells damaged by UVC. These results suggest that mPer2 plays a protective effect on cells damaged by UVC, whose mechanism may be involved in upregulated p53.

• 한국재료학회지
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• 제2권4호
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• pp.279-284
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• 1992

고분해능 전자에너지손실 및 자외선광전자 분광법을 사용하여 단결정 NbC(111)면의 산소횹착을 연구하였다. NbC(111) 표면에는 산소가 원자 및 분자상태로 흡착되었다. 산소원자는 3-fold hollow site에 흡착되며 진동수는 548c$m^{-1}$이었다. 산소분자의 신축진동수는 968c$m^{-1}$로서 기체상태인 산소분자의 진동수보다 크게 낮았으며, 산소분자의 흡착으로 일함수가 증가하였다. 이는 NbC(111) 기판으로부터 산소분자의 2p${pi}_g$ 궤도로 전자가 이동하였음을 보여주는 증거이다.

• 한국산림과학회지
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• 제85권2호
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• pp.225-237
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• 1996

다수성 계통으로 선발된 한국산 팽나무버섯의 두 계통을 톱밥배지에 배양하여 여러 환경조건과, 균사배양배지의 이화학적인 전처리가 자실체 형성에 미치는 영향을 조사하였다. 배지의 비선택성, $11^{\circ}C{\sim}15^{\circ}C$의 최적온도, 90%의 최적상대습도 및 60 lux의 조도조건에서는 두 계통간에 차이를 보이지 않았다. 전처리결과는 배지를 $5^{\circ}C$와 $10^{\circ}C$, $5^{\circ}C$와 $15^{\circ}C$의 변온처리, 30~50초의 자외선처리, 5초의 전기처리 및 0.05~0.1%의 Thiamine HCl처리에서 자실체 형성에 좋은 결과를 보였으나 두 계통간에 차이를 보이지 않았다. 그러나 요소용액과 IAA용액처리는 두 계통에서 모두 효과를 기대할 수 없었다. 자실체의 형성량이나 크기에서 나타난 두 계통의 특성에 있어서 갈색계통은 황색계통에 비하여 갓이 큰 대산종(大傘種)이며 대가 긴 장병종(長柄種)이었다. 한편 황색계통은 갈색계통에 비하여 자실체 형성중량과 형성수량이 많았으며 소산종(小傘種)이고 단병종(短柄種)으로 확인되었다.

• Journal of Microbiology and Biotechnology
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• 제33권1호
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• pp.106-113
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• 2023

The supply of microbiological risk-free water is essential to keep food safety and public hygiene. And removal, inactivation, and destruction of microorganisms in drinking water are key for ensuring safety in the food industry. Ultraviolet-C (UV-C) irradiation is an attractive method for efficient disinfection of water without generating toxicity and adversely affecting human health. In this study, the disinfection efficiencies of UV-C irradiation on Shigella flexneri (Gram negative) and Listeria monocytogenes (Gram positive) at various concentrations in drinking water were evaluated using a water purifier. Their morphological and physiological characteristics after UV-C irradiation were observed using fluorescence microscopy and flow cytometry combined with live/dead staining. UV-C irradiation (254 nm wavelength, irradiation dose: 40 mJ/cm²) at a water flow velocity of 3.4 L/min showed disinfection ability on both bacteria up to 10⁸ CFU/4 L. And flow cytometric analysis showed different physiological shift between S. flexneri and L. monocytogenes after UV-C irradiation, but no significant shift of morphology in both bacteria. In addition, each bacterium revealed different characteristics with time-course observation after UV-C irradiation: L. monocytogenes dramatically changed its physiological feature and seemed to reach maximum damage at 4 h and then recovered, whereas S. flexneri seemed to gradually die over time. This study revealed that UV-C irradiation of water purifiers is effective in disinfecting microbial contaminants in drinking water and provides basic information on bacterial features/responses after UV-C irradiation.

• 산업식품공학
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• 제22권4호
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• pp.386-391
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• 2018

양산형 UV-P 처리는 장비를 20분 이상 작동하였을 때 후춧가루의 토착 중온 호기성 세균을 유의적으로 저해시켰다. UV-P 처리는 토착 미생물 저해에 있어 상승효과를 보여주었으나 후춧가루의 색을 어둡게 하였다. UV-P 처리의 후춧가루 미생물 저해 효과와 색 변화에 대한 영향은 처리되는 후춧가루를 오염시키는 미생물과 후춧가루 종류에 영향을 받음을 알 수 있었다. 또한 본 연구 결과는 UV-P 장비 내 플라즈마 충적 시간과 후춧가루의 $a_w$ 상승이 UV-P 처리된 후춧가루의 미생물 저해 효과 향상과 색 유지에 효과적이지 않음을 알 수 있었다. 본 연구는 UV-C와 플라즈마 처리를 병합한 양산형 UV-P 처리가 후춧가루의 토착 미생물을 저해시키는 기술로서의 가능성을 보여주었다. 그러나 앞으로 추가적인 연구를 통해 UV-P 처리부의 온도상승 및 후춧가루의 색도 변화를 최소화할 수 있는 방법이 제시되어야 할 것이다.

• BMB Reports
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• 제35권5호
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• pp.452-458
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• 2002

Exposure to ultraviolet light (UV) induces apoptosis in mammalian cells, The caspase group of proteases is required for the appotosis. This pathway is initiated by a release of cytochrome c from the mitochondria into the cytosol. Several Bcl-2 family proteins can regulate the release of cytochrome c by stabilizing the mitochondrial membrane. Here we show that expression of the endogenous bcl-xL was strongly downregulated in NIH3T3 cells within 2 h after UV-C irradiation, and that of bax was upregulated from 8 h after irradiation. Apoptosis was induced in more than 50% of the NIH3T3 cells 48 h after irradiation. Constitutive overexpression of bcl-xL in NIH3T3 cells protected the UV-induced apoptosis by preventing the loss of mitochondrial membrane potential and the activation of caspase 9. There results suggest that downregulation of Bcl-xL is relevant to UV-induced apoptosis of tibroblasts.

• 한국염색가공학회지
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• 제23권3호
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• pp.179-186
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• 2011

For the application of Jeju scoria scattered around the island as a natural dye, cotton fabrics were dyed with the dye and their properties were measured including dyeability, colorfastness, antibacterial activity, deodorization efficiency, ultraviolet protection, and far-infrared emission. The dyed cotton fabrics were in yellowish red and optimal dyeing conditions were obtained with a colorant concentration of 25%(o.w.b) at a temperature of $80^{\circ}C$ for the dyeing time of 120 minutes. The ratings of colorfastness to light, rubbing, perspiration, and washing were 8, 5, 5, and 4~5 respectively. After 15 wash cycles, colorfastness remained as much as 4~5 rating. The cotton fabric dyed with Jeju scoria demonstrated excellent antimicrobial activity and deodorization efficiency of 99.9% and 93.9% respectively. Ultraviolet protection factor was 50+. Far-infrared emission rate and far-infrared emission intensity were 90% and 362(W/$m^2{\cdot}{\mu}m$) respectively. The Jeju scoria can be introduced as a new colorant for the natural dyeing of cotton.