• Current Optics and Photonics
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• 제2권3호
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• pp.286-290
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• 2018

We investigated the dependence of the retardation dispersion on the polarization direction of ultraviolet (UV) light during the photopolymerization of self-organized smectic reactive mesogen (RM) molecules. RM retarder film that was photopolymerized with UV light linearly polarized parallel to the layer plane showed negative dispersion (ND) of retardation for a wide range of UV polymerization temperatures. On the other hand, film that was photopolymerized with unpolarized UV light showed negative dispersion in a narrow range of UV polymerization temperatures. With a certain UV polymerization temperature, the dispersion of retardation was converted from positive to negative, depending on the UV polarization.

• Molecules and Cells
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• 제42권11호
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• pp.794-803
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• 2019

Ultraviolet light (UV)-induced cellular response has been studied by numerous investigators for many years. Long noncoding RNAs (lncRNAs) are emerging as new regulators of diverse cellular process; however, little is known about the role of lncRNAs in the cellular response to UV treatment. Here, we demonstrate that levels of lncRNA-HOTTIP significantly increases after UV stimulation and regulates the UV-mediated cellular response to UV through the coordinate activation of its neighboring gene Hoxa13 in GC-1 cells (spermatogonia germ cell line). UV-induced, G2/M-phase arrest and early apoptosis can be regulated by lncRNA-HOTTIP and Hoxa13. Furthermore, lncRNA-HOTTIP can up-regulate ${\gamma}-H_2AX$ and p53 expression via Hoxa13 in UV-irradiated GC-1 cells. In addition, p53 has the ability to regulate the expression of both lncRNA-HOTTIP and Hoxa13 in vitro and in vivo. Our results provide new data regarding the role lncRNAs play in the UV response in spermatogenic cells.

• 조명전기설비학회논문지
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• 제25권3호
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• pp.7-14
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• 2011

Many countries and researchers in the lighting field have focused on the LED light source as a solution to energy savings and environmental pollution. The LED light source consumes less power, has a long life and is highly economical. It is vibration and shock-resistant, and environment friendly as well. But LED lighting has some problems. In particular, the photobiological safety of LED light sources is emerging as an issue. Ultraviolet radiation from the LED light source emitted directly to the human body over a long period of time is harmful. In this paper, UV radiation from white LED was measured. Finally, the LED light source emits UV radiation, but it is relatively small when compared to others.

• 응용화학
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• 제15권1호
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• pp.17-20
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• 2011

A disposable light exposure detector kit has been developed by UV curing of a hydrogel material. The devised light exposure detector kit consisted of light sensitive structures, bottom plate, character sheet and sticky back plate. A light exposure detector kit has a serial light sensitive structures that contain various light sensitive dyes such as rhodamine and fluorescein. The light sensitive structure composed of UV curable hydrogel polymer material as a supporing material and photosensitive dye in a certain concentration. The fabrication procedure of the ligh exposure detector kit is very simple and fast due to UV curing procedure of a photopolymerizable hydrogel material such as poly(ethylene glycol) methyl ether acrylate (PEGMEA) and poly(ethylene glycol) diacrylate (PEGDA) with a photosensitive dye. By the proposed fabrication method, various size and shape of a light exposure detector kit could be fabricated using a flexible elastomer mold. Due to a fast and inexpensive fabrication method, the light exposure detector kit could be use a single use for various industrial applications. According to light irradation, the light sensitive structure on a light exposure detector kit could be lose its color by decomposition of a photosensitive dye chemical in the structure. Thus the amount of the exposed light on a substrate could easily be recognised by changing color or transparency of the structure.

• 대한지구과학교육학회지
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• 제8권3호
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• pp.267-280
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• 2015

The purpose of this study is to identify the conceptions of middle school students and teachers about Visible-Light, Ultra-Violet(UV) and Infrared-Ray(IR). We administered questionnaire 3 teacher and 102 students(48 people of middle school 2nd students and 54 people of middle school 3rd students) who learned by 3 teachers in seoul. From the analysis, it was found that many students and teachers didn't understand the basic principle of UV and IR. Significant number of students belive that it is possible to see objects the absence of visible light. Most students belive that they can see objects in the presence of UV light alone. They think that "Light" is single concept. Teachers were generally more aware of the origin and explanation of UV. But teachers expressed some uncertainties. They tend to think negative effect for UV.

• 분석과학
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• 제30권4호
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• pp.159-166
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• 2017

Exposure to UV light, i.e., UV-A (320-400 nm) or UV-B (290-320 nm) radiation, can cause skin cancer. Titanium dioxide ($TiO_2$) effectively disperses UV light. Therefore, it is used as a physical UV filter in many UV light blockers. Usually, the $TiO_2$ content in commercialized UV blockers is 25 % at most. To block UV-B, a chemical UV blocker, octyl-methoxy cinnamate (OMC) is used. OMC is commonly used in combination with $TiO_2$. In this study, $TiO_2$ and OMC were mixed in different proportions to produce UV blockers with different compositions. Also the changes in the sun protection factor (SPF) based on the composition and $TiO_2$ particle sizes were investigated. In order to analyze the $TiO_2$ particle size, dynamic light scattering (DLS) and asymmetrical flow field-flow fractionation (AsFlFFF) were used. The results showed that the SPF was influenced by the proportion of $TiO_2$ and OMC, where the proportion of $TiO_2$ induced a more significant influence. In addition, changes in the $TiO_2$ particle size based on the proportion of OMC were observed.

• 한국안광학회지
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• 제13권3호
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• pp.7-12
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• 2008

목적: 투명과 착색 안경렌즈의 자외선 차단 특성을 평가하고자 하였다. 방법: 안경렌즈의 투과 스펙트럼은 ANSI Z80.1에 제시된 방법으로 측정하였고, UV(200~380 nm; UVA, UVB, UVC) 및 청색광 영역(380~400 nm)에 대하여 각 렌즈의 투과율을 계산하였다. 결과: 중굴절률, 고굴절률의 투명 플라스틱 렌즈 및 착색 플라스틱 렌즈는 UV에서 우수한 자외선 차단 특성을 보였으나, 자외선 차단제를 처리하지 않은 크라운 유리나 CR39는 그렇지 않았다. 고굴절률 렌즈와 눈부심 방지 야간용 렌즈를 제외한 모든 렌즈는 청색광을 효과적으로 차단하지 않았다. 결론: 크라운 유리와 CR39 렌즈는 UV로부터 눈을 보호하기 위해서 자외선 차단제가 필요하다. 또한 고굴절률 렌즈와 눈부심 방지 야간용 렌즈를 제외한 모든 렌즈는 청색광으로부터 눈을 보호하기 위해서 청색광 차단제가 필요하다.

• Bulletin of the Korean Chemical Society
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• 제33권5호
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• pp.1753-1758
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• 2012

A novel, efficient and controlled protocol for the synthesis and enhanced photocatalytic activity of $Au@TiO_2$ nanocomposite is developed. $TiO_2$ (P25) was pretreated by employing UV light (${\lambda}$ = 254 nm) and the pretreated $TiO_2$ was uniformly decorated by gold nanoparticles (AuNPs) in presence of sodium citrate and UV light. UV pretreatment makes the $TiO_2$ activated, as electrons were accumulated within the $TiO_2$ in the conduction band. These accumulated electrons facilitate the formation of AuNPs which were of very small size (2-5 nm), similar morphology and uniformly deposited at $TiO_2$ surface. It leads to formation of stable and crystalline $Au@TiO_2$ nanocomposites. The rapidity (13 hours), monodispersity, smaller nanocomposites and easy separation make this protocol highly significant in the area of nanocomposites syntheses. As-synthesized nanocomposites were characterized by TEM, HRTEM, TEM-EDX, SAED, XRD, UV-visible spectrophotometer and zeta potential. Dye degradation experiments of methyl orange show that type I ($Au@TiO_2$ nanocomposites in which $TiO_2$ was pretreated with UV light) has enhanced photocatalytic activity in comparison to type II ($Au@TiO_2$ nanocomposites in which $TiO_2$ was not pretreated with UV light) and $TiO_2$ (P25). This shows that pretreatment of $TiO_2$ provides type I a better catalytic activity.

• 대한치과보철학회지
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• 제37권3호
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• pp.343-357
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• 1999

The color change of maxillofacial silicone has been attributed to certain environmental factors such as exposure to the UV component of natural sunlight, wetting and drying of the elastomer and surface abrasion resulting from the application and removal of cosmetics. The purpose of this study was to evaluate the color change of maxillofacial silicone (Silastic MDX4-4210) according to type of pigment (cadmium yellow, titanium white, cosmetic red), and UV absorber application method after 200, 400, and 600 hours of 350nm UV light irradiation. The results were as follows. 1. According to type of pigments, after 200 hours cosmetic red showed significantly larger color change than cadmium yellow and titanium white, and after 400 and 600 hours color change significantly decreased in the order of cosmetic red, cadmium yellow, and titanium white (p<0.05). 2. In the cadmium yellow group, after 200 hours, the non-treatment group showed significantly larger color change, but after 400 and 600 hours, color change significantly decreased in the order of non-treatment, surface application and mixed group (p<0.05). 3. In the titanium white group, there was no significant color change difference between the three groups after 200 and 400 hours, but after 600 hours, the mixed group showed significantly smalt or color change than the non-treatment and surface application groups (p<0.05). 4. In the cosmetic red group, there was significant decrease in color change in the order of non-treatment, surface application and mixed group (p<0.05). From the results above, the effect of UV light absorber differed according to the type of pigment, but mixing UV light absorber with maxillofacial silicone is thought to give superior resistance against UV light irradiation in the long run.

• 한국조경학회지
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• 제40권5호
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• pp.1-7
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• 2012

실내 광환경은 자연 상태와 달라 실내 조경 식물의 생장 및 생리활성에 영향을 줄 것으로 생각된다.본 연구는 광질(光質)이 월계수의 생장 및 생리활성에 미치는 영향을 평가하기 위해 실시하였다. 월계수 묘목은 4개의 다른 광원 처리구(control, +UV, -FR, +UV-FR 처리구)에서 180일 동안 생육시켰다. 자외선 추가 처리구(+UV)에서 생육한 월계수는 건중량 및 잎 면적이 감소되었지만, 잎 두께 및 잎내 자외선 흡수 물질의 함유량은 증가했다. 반면, 원적외선 차단 처리구(-FR)에서 생육한 월계수는 큰 변화를 나타내지 않았다. 하지만, 자외선 추가 및 원적외선 차단 처리구(+UV-FR)에서 생육한 월계수는 신장생장 및 광합성 속도가 유의적으로 저하했다(P<0.05).이상의 결과, 광질이 실내 조경 식물인 월계수의 생장 및 생리활성에 큰 영향을 주는 것으로 밝혀졌다. 실내 조경 식물인 월계수를 관리할 때 광질을 이용한 관리의 기초 자료로 활용될 수 있을 것이다.