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        검색결과 25

        1.
        2024.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this study, two alignment methods were used to create a Fringe-Field Switching (FFS) mode liquid crystal device using an organic thin film (polyimide: PI) as an alignment layer. In addition, the electro-optical (EO) characteristics of the liquid crystal device manufactured in this way were investigated to evaluate the feasibility of mass production application of the technology. In general, the photo-alignment method using unpolarized ultraviolet rays can obtain a relatively low pretilt angle, so a liquid crystal device in FFS mode, which is a driving mode of the liquid crystal device that reflects the characteristics of liquid crystal alignment, was manufactured, and the liquid crystal has a high reactivity with the alignment film. Considering this, nematic liquid crystal (NLC) was used. In addition, in order to improve the misalignment, it was observed whether more stable orientation occurred by irradiating ultraviolet rays for an additional 1 to 3 hours in the aligned state. As a result of the experiment, it was found that NLC alignment occurs through a photodecomposition reaction caused by unpolarized UV irradiation oblique to the PI surface. In addition to the existing orientation method, UV irradiation was used to achieve a more stable orientation state and stable V-T curve and response characteristics. With liquid crystal alignment completed, more stable orientation characteristics and EO characteristics at the mass production level were obtained through additional UV irradiation for 3 hours. This method can further stabilize the orientation stability caused by existing UV irradiation through an additional process.
        4,000원
        2.
        2023.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        High-risk microbial pathogens are handled in a biosafety laboratory. After experiments, the pathogens may remain as contaminants. To safely manage a biosafety laboratory, disinfection of microbial contaminants is necessary. This study was carried out to evaluate the effect of UV-C irradiation for the disinfection of a high-risk plant pathogenic bacterium Erwinia amylovora in a laboratory setting. For the test, the bacterium (8.7 × 106 CFU/ml) was embedded on the surface of PDA and placed on the work surface in a biosafety cabinet (Class 2 Type A1), and on the three different surfaces of the laboratory bench, laboratory bench shelf, and the floor which were positioned in a straight line from the UV lamp installed in the ceiling of the biosafety laboratory (BSL 2 class). UV-C irradiation was administered for 10min, 30min, 1 hr, 2hr, 3 hr, and 4hr, respectively. The reduction rate of bacteria ranged from 95% to 99% in regard to 10 min irradiation, from 97% to 99% in regard to 30 min irradiation, from 99.8% to 99.9% in regard to 1 hr irradiation, and higher than 99.99% in regard to 2 hr irradiation. The bacterium was completely inactivated after 3 hr irradiation. A similar UV-C irradiation effect was obtained when the bacterium was placed at a distance of 1 m from the three different surface points. Bacterial reduction by UV-C irradiation was not significantly different among the three different surface points.
        4,000원
        3.
        2022.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Carbon fibers (CFs) are considered promising composite materials for various applications. However, the high cost of CFs (as much as $26 per kg) limits their practical use in the automobile and energy industries. In this study, we developed a continuous stabilization process for manufacturing low-cost CFs. We employed a textile-grade polyacrylonitrile (PAN) fiber as a low-cost precursor and UV irradiation technique to shorten the thermal stabilization time. We confirmed that UV irradiation on the textile-grade PAN fibers could lower the initial thermal stabilization temperature and also lead to a higher reaction. These resulted in a shorter overall stabilization time and enhancement of the tensile properties of textilegrade PAN-based CFs. Our study found that only 70 min of stabilization time with UV irradiation was required to prepare textile-grade PAN-based low-cost CFs with a tensile strength of 2.37 ± 0.22GPa and tensile modulus of 249 ± 5 GPa.
        4,000원
        5.
        2017.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In the present study, we investigated the protective effect of various grain methanolic extracts against UVB-induced photo-aging in human skin fibroblasts. Various grain methanolic extracts were evaluated for their antioxidant compounds and activities. 2,2-Ddiphenyl-1-picryhydrazyl radical (DPPH) and ABTS 2,2-azino-bris-(3-ethylbenzoth iazoline-6-sulphonic acid) radical cation scavenging activities have been used to measure the relative antioxidant activities of extracts from grains. The content of total polyphenolics in the extracts were evaluated using spectrophotometric methods. Human skin fibroblast (Hs68) cells were pretreated with various grain methanolic extracts (25 μg/mL). Skin toxicity was simulated by exposing the cells to UVB (30 mJ/cm2) irradiation. In response to the UVB-irradiation, an increased amount of matrix metalloproteinases (MMPs) release was observed, whereas pretreatment of various grain methanolic extracts significantly inhibited the production of MMP-1 in Hs68 cells. We also found that pretreatment of the extracts significantly decreased UVB-induced reactive oxygen species and significantly increased total collagen content in Hs68 cells. These results provide that grains could be regarded as a potential ingredient in natural cosmetics, used for UVB protection.
        4,000원
        6.
        2012.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구에서는 딸기의 건강기능성 효과를 증대시키기 위해 자외선 처리를 하였을 때 매향, 장희, 육보 딸기의 생물활성이 어떻게 변화하는지 살펴보았다. 본 연구는 과실류 및 채소류의 수확 이후에도 세포 활성이 유지된다면 자외선 등 여러 가지 외부 자극을 통해 2차 대사산물이 세포 대사에 의해 유도합성이 가능하다는 기작에 근거하여 딸기의 생물활성이 향상될 수 있다는 가설에 근거를 두고 있다. 본 연구에서 딸기의 생물활성은 항산화 효능, 해독화 효소 발현 조절 능력, 암세포 사멸 능력 및 항염증 효능 측면에서 평가되었다. 평가 결과에 의하면, 딸기의 품종과 UV 조사량에 따라 다소의 차이는 있으나 전반적으로 딸기 수확후 자외선을 조사하면 항산화 효능, 해독화 효소 발현 조절 능력, 암세포 사멸 능력 등이 향상되는 것을 확인할 수 있었다. 그러나 항염증 효능은 자외선 처리 효과가 거의 없는 것으로 나타났다. 본 연구의 결과를 전체적으로 살펴볼 때, 딸기 수확 이후 자외선 자극을 통해 생물활성이 향상될 수 있음을 확인하였으나 후속연구를 통해 보다 정밀한 기작에 대한 규명이 뒤따라야 함을 또한 지적해 두고자 한다.
        4,000원
        8.
        2008.09 구독 인증기관 무료, 개인회원 유료
        Anti-wrinkle effect of herbal extracts was investigated on the skin of in a model of animal irradiated by ultraviolet rey B (UVB). The female albino hairless mice (HR/ICR) were randomly allocated to the normal control group (NC-non irradiated-vechicle), positive control group (PC, UVB irradiated vehicle) and herbal extract (HE) group. The herbal extract included the mixture of water and alcohol extract from Pleuropterus multflorus, Lonicera japonica Thunbert, Phellinus linteus, and Phaseolus radiatus. The herbal extract was treated dorsally with 0.2 ml per mouse five times a week for 12 weeks. At fifth week of the treatment, the animals were exposed to UVB irradiation for subsequent eight weeks three times a week. The intensity of irradiation was gradually increased from 30 mJ/㎠ to 240 mJ/㎠ (1MED: 60 mJ/㎠). Dorsal skins were obtained and stained with H&E to examine histological changes and epidermal/dermal thckness. The collagen fiber was also observed in Masson-Trichrome staining. Hydroxyproline assay and western blot analysis were also carried out to detect the change of collagen amount and to investigate MMP-1 expression, respectively. The HE group showed a better appearance and weak wrinkling, compared to PC group, The treatment of herbal extract significantly increased the thickness of dermis and the amount of collagen fibers compared to PC group (p<0.05). The treatment of HE significantly increased the hydroxyproline amount compared to PC group (p<0.05). The chronic UVB irradiation to hairless mice skin increased expression of MMP-1 but the treatment of HE decreased the expression of MMP-1. These results indicate that the herbal extract used in this study have a preventive effect on the UVB-induced wrinkle in a hairless mice model, partly due to the reduction of MMP-1 expression and increment of collagen amount.
        4,000원
        11.
        2001.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study was to investigate the effect of ultraviolet rays, soaking, boiling and baking to ergocalciferol (Vit.D2) and riboflavin(Vit.B2) contents of mushrooms, Lentinus edodes, Pleurotus ostreatus and Agaricus bisporus. The results were as follow: 1. Mushrooms were exposed to ultraviolet rays Lentinus edodes : 10J/cm2, Pleurotus ostratus : 2J/cm2 and Agaricus bisporus : 2J/cm2. 2. Before exposing to ultraviolet rays, the ergocalciferol contents of mushrooms were all 0μg/g dry base, but after exposing to it , those of Lentinus edodes, Pleurotus ostreatus and Agaricus bisporus were 222.50±5.30μg/g dry base, 150.90±6.60μg/g dry base and 23.98±1.20μg/g dry base, respectively 3. Before and after exposing to ultraviolet rays, the riboflavin contents of Lentinus edoes, Pleurotus ostreatus and Agaricus bisporus were 18.22±0.71μg/g dry base and 11.72±0.50μg/g dry base, 4.57±0.20μg/g dery base and 3.26±0.15μg/g dry base, and 37.42±1.20μg/g dry base and 27.33±2.10μg/g dry base, respectively. 4. The ergocalciferol contents of mushrooms according to boiling time were not significantly different but the riboflavin contents of them were decreased according to the increase of boiling time. 5. The ergocalciferol and riboflavin contents of mushrooms were decreased according to the increase of NaCl concentration and baking temperature. 6. The ergocalciferol content of Lentinus edodes after a short time soaking at 80℃ was higher than a long time soaking at 20℃, 40℃ and 60℃.
        4,000원
        13.
        2018.09 KCI 등재 SCOPUS 서비스 종료(열람 제한)
        식물의 이차 대사산물은 다양한 생물활성을 가지며 자외선은 이차 대사산물의 생성에 영향을 미치는 것으로 알려져 있다. 뽕나무는 다양한 종류의 유용 성분을 함유하여 활용가치가 높은 식물 중의 하나이다. 본 연구에서는, UV 조사에 따른 뽕나무 잎의 이차 대사산물의 변화를 조사하기 위하여, 뽕나무 잎을 LC-MS를 이용하여 무표적 분석법으로 분석하였으며, 무표적 분석으로 얻은 scan data를 bioinformatics 프로그램인 R의 XCMS package를 이용하여 profiling 한 결과, 적어도 35종 이상의 화합물에서 UV-C 조사에 따른 양적인 변화가 발견되었다. 이들 중 14종의 화합물은 분리 및 NMR spectrum 비교 또는 표적 분석을 통하여 종류를 확인하였으며, 종류가 확인된 성분에 대해 정량분석을 수행한 결과, morin(464배), oxyresveratrol(256배), 2,3-trans-dihydromorin(170배), 2",4",2,4-tetrahydroxychalcone(120배), catechin(84배), 4"-prenyloxyresveratrol(43배), moracin M(35배) 등의 함량이 현저하게 증가한 것으로 나타났다. 또한 UV-C를 조사한 뽕나무 잎은 대조구에 비하여 항산화 활성이 2.1-2.4배, tyrosinase 억제 활성이 2.3배 증가한 것으로 조사되었다. 이러한 조사 결과는 자외선의 조사가 뽕나무 잎의 기능성을 향상시켜 기능성 식품, 약용 또는 화장품 소재로서의 활용 가치를 향상시키는 유용한 수단이 될 수 있음을 보인다.
        14.
        2017.12 KCI 등재 서비스 종료(열람 제한)
        본 연구에서는 국내 유통 중인 자외선 차단 기능성화장품 총 100건을 대상으로 살균보존제 16종과 자외 선차단성분 18종의 사용실태를 조사하였다. 그 결과, 검출률이 가장 높은 살균보존제 성분 5가지는 페녹시에탄 올(61건), 안식향산(19건), 메틸파라벤(11건), 벤질알콜(8건), 프로필파라벤(7건)순이었으며, 자외선차단성 분의 경우는 티타늄디옥사이드(81건), 에칠헥실메톡시신나메이트(69건), 징크옥사이드(48건), 에칠헥실살리 실레이트(48건), 비스-에칠헥실옥시페놀메톡시페닐트리아진(44건)순이었다. 검사한 100건의 화장품 모두 검 출된 살균보존제와 자외선차단성분 함량이 식품의약품안전처에서 정한 사용한도 기준에 적합하였지만 일부 자 외선 차단 화장품의 경우 포장⋅용기에 표시되어 있지 않은 살균보존제와 자외선차단성분이 검출되었다. 100건 중 31건의 화장품에서 표시되지 않은 살균보존제 성분(벤질 알콜 등 6종)이 검출되었고, 2건에서는 표시되지 않은 자외선차단성분(호모살레이트 등 2종)이 검출되었다.
        15.
        2017.06 KCI 등재 SCOPUS 서비스 종료(열람 제한)
        Ergocalciferol is known as having vitamin D activity. In this study, the effects of UV irradiation on the increase of egocalciferol content were investigated in 7 kinds of mushrooms, i.e, lily mushroom (Flammulina velutipes), oyster mushroom (Pleurotus ostreatus), young oyster mushroom (Pleurotus ostreatus), king oyster mushroom (Pleurotus eryngii), button mushroom (Agaricus bisporus), shiitake (Lentinula edodes), and wood ear mushroom (Auricularia auricula-judae). Mushrooms which were not exposed to UV light contained negligible amount of ergocalciferol in all kinds of tested mushrooms, but UV irradiation increased their content of ergocalciferol. Of UV A, B and C, UV B light was the most effective to increase ergocalciferol contents. In mushrooms, the increase in ergocalciferol content occurred only in the peel within 1 mm depth from the surface, which was directly exposed to the UV light. Therefore, when fresh whole mushrooms were irradiated with UV light, lily mushroom, the mushroom with a larger surface area compared to volume, such as lily mushroom, was more favorable in producing ergocalciferol. On the other hand when the mushrooms were freeze-dried and cut, the mushrooms with a higher ergosterol, such as king oyster mushroom, shiitake or button mushroom, were more favorable in generating ergocalciferol.
        16.
        2013.09 KCI 등재 서비스 종료(열람 제한)
        본 연구는 자외선 차단지수(Sun protection Factor, SPF) 측정 시험에서 피험자의 안전을 확보하고 정확한 시험결과를 통해 향후 자외선 조사시험의 기초 데이터 확보 및 연구자료 마련을 목적으로 하였다. 피부유형 기준표에 따라 피험자의 피부유형 Ⅰ, Ⅱ, Ⅲ 형에 해당되는 피험자 395명을 대상으로 하였다. 색차계를이용하여 피부색을 측정한 뒤 ITA (Individual Typology Angle) 값을 계산하고 그 값이 28 이상인 사람을대상으로 편안한 자세를 취하도록 하여 자외선을 60 s 간 조사한 후 24 h 뒤 피험자의 홍반 상태를 판정하였다.전면에 홍반이 나타난 부위에 조사한 UVB의 광량 중 최소량을 최소홍반량(Minimal Erythema Dose, MED)으로 하였다. 통계학적 분석은 Statistical Package for the Social Sciences 프로그램을 사용하였다. 피부 유형이높아질수록 MED 값이 증가하여 피부색이 어두워질수록 MED가 증가한다는 결과를 얻을 수 있었다. 또한 여성이 남성보다 높은 MED로 여성이 남성보다 어두운 피부유형을 가진 것으로 나타났고, 연령별 MED는 피부타입별 모든 연령대에서 연관성이 없었으나 이 같은 결과를 단정 짓기에는 성별, 연령대별 피험자 수가 적어 통계적유의성을 뒷받침하는데 한계가 있을 것으로 생각된다. 본 연구를 통해 얻은 피부유형별 MED 측정값은 자외선차단제를 사용하기 전 MED 값을 예상하여 자외선차단제의 효능 평가 시 비교, 판독을 할 수 있는 기준이 되므로임상에 안전하게 적용할 수 있는 기초자료로써 유용하게 쓰일 수 있을 것이다.
        17.
        2012.07 KCI 등재 서비스 종료(열람 제한)
        Diethyl phthalate (DEP) is widely spread in the natural environment as an endocrine disruption chemicals (EDs). Therefore, in this study, ultrasound (US) and ultraviolet (UVC), including various applied power density (10-40 W/L), UV wavelengths (365 nm, 254 nm and 185 nm) and frequencies (283 kHz, 935 kHz) were applied to a DEP contaminated solution. The pseudo-first order degradation rate constants were in the order of 10-1 to 10-4 min-1 depending on the processes. Photolytic and sonophotolytic DEP degradation rate also were high at shortest UV wavelength (VUV) due to the higher energy of photons, higher molar absorption coefficient of DEP and increased hydroxyl radical generation from homolysis of water. Sonolytic DEP degradation rate increased with increase of applied input power and the dominant reaction mechanism of DEP in sonolysis was estimated as hydroxyl radical reaction by the addition of t-BuOH, which is a common hydroxyl radical scavenger. Moreover, synergistic effect of were also observed for sonophotolytic degradation with various UV irradiation.
        18.
        2010.06 KCI 등재 서비스 종료(열람 제한)
        Anthocyanin and polyphenolic compounds present in fruits of mulberry (Morus alba L.) were determined and the influence of temperature and UV irradiation on stability of the anthocyanin-copigment complex were investigated. The copigmentation substance selected in non-anthocyanin fraction from mulberry for the study included: phenolic acid (hydroxybenzoic acid) and flavonoid (quercetin-3-O-β-D-glucopyranoside). The copigmentation effect increased with the copigment content. UV irradiation had a stronger degradation effect on the copigmentation complex than heating at 80℃. The non-anthocyanin fraction of mulberry and isolated flavonoid (quercetin-3-O-β-D-glucopyranoside) from mulberry fruit predominated over other copigment substances.
        19.
        2009.10 KCI 등재 서비스 종료(열람 제한)
        Sunlight, and in particular its UV component, is the major environmental trigger that underlies the major signs of human skin and skin cancer in general. Therefore, this study was carried out to investigate the UV protection effects of R. coreanus. R. coreanus was extracted by ultra high pressure extraction process at 500 MPa and 30℃ for 5 and 15 minutes. The cytotoxicity of the extracts extracted by ultra high pressure process on human dermal fibroblast cell CCD-986sk, human kidney normal cell HEK293, and human lung normal cell HEL299 was measured as 17.5%, 16.5% and 14.0%, respectively in adding 1.0 mg/ml of the samples, which was much lower than that from conventional water extraction method at 100℃ as 23.2%, 22.5%, 21.2%. The secretion of NO- from macrophage showed 15.9 μM on the R. coreanus extract from this process, which was higher than others. Prostaglandin E2 (PGE2) production from UV-induced human skin cells was also greatly decreased down to 510 pg/ml, compared to the control. From the results, we considered that the extracts from R. coreanus could be potent natural materials for skin anti-inflammation agent, and could be used as a potential anti-aging for the photo-damaged skin.
        20.
        2008.12 KCI 등재 서비스 종료(열람 제한)
        본 연구에서는 모발의 내부 및 외부구조에 자외선이 미치는 영향에 관하여 조사를 수행하였다. 자외선이 조사된 모발의 형태학적 및 화학적 구조의 변화를 알아보기 위해 주사전자현미경(SEM), 투과전자현미경(TEM), 공초점레이져주사현미경(CLSM) 등을 사용하였다. SEM상에서 자외선이 조사된 모발은 자외선에 의한 화학적 산화반응에 의해 표면이 거칠고 부풀어진 형태를 보였다. 이황화결합(disulfide bond)의 산화에 의한 시스테인산(cysteic acid)의 분해로 팽윤부위가 관찰되었다. 또한 자외선 조사에 의해 표면색의 변화를 나타내었다. TEM 분석결과 버진헤어(virgin hair)의 경우에는 매끄러운 표면구조를 나타내었지만, 자외선 조사모발에 있어서는 거칠고 모수질층이 갈라진 형태를 보여주었다. 모피질층에 존재하는 멜라닌 입자의 크기가 감소하고 소실되는 것이 관찰 되었다. CLSM에 의해 3차원적 구조의 입체영상을 얻을 수 있었으며, 광학분할에 의해 버진헤어는 강한 형광을 나타내었지만, 자외선 조사모발은 낮은 형광을 보여주었다. 이는 버진헤어의 경우 자동형광을 나타낼 수 있는 방향족 아미노산이 많이 존재하는데 비해 자외선 조사모발은 방향족 아미노산이 파괴되어 낮게 나온 것으로 여겨진다.
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