• Toxicological Research
• /
• 제31권2호
• /
• pp.97-104
• /
• 2015

The skin exposure to solar irradiation and photoreactive xenobiotics may produce abnormal skin reaction, phototoxicity. Phototoxicity is an acute light-induced response, which occurs when photoreacive chemicals are activated by solar lights and transformed into products cytotoxic against the skin cells. Multifarious symptoms of phototoxicity are identified, skin irritation, erythema, pruritis, and edema that are similar to those of the exaggerated sunburn. Diverse organic chemicals, especially drugs, are known to induce phototoxicity, which is probably from the common possession of UV-absorbing benzene or heterocyclic rings in their molecular structures. Both UVB (290~320 nm) and UVA (320~400 nm) are responsible for the manifestation of phototoxicity. Absorption of photons and absorbed energy (hv) by photoactive chemicals results in molecular changes or generates reactive oxygen species and depending on the way how endogenous molecules are affected by phototoxicants, mechanisms of phototoxcity is categorized into two modes of action: Direct when unstable species from excited state directly react with the endogenous molecules, and indirect when endogeneous molecules react with secondary photoproducts. In order to identify phototoxic potential of a chemical, various test methods have been introduced. Focus is given to animal alternative test methods, i.e., in vitro, and in chemico assays as well as in vivo. 3T3 neutral red uptake assay, erythrocyte photohemolysis test, and phototoxicity test using human 3-dimensional (3D) epidermis model are examples of in vitro assays. In chemico methods evaluate the generation of reactive oxygen species or DNA strand break activity employing plasmid for chemicals, or drugs with phototoxic potential.

• 한국진공학회:학술대회논문집
• /
• 한국진공학회 2011년도 제41회 하계 정기 학술대회 초록집
• /
• pp.162-162
• /
• 2011

Nanometer-sized noble metals can trap and guide sunlight for enhanced absorption of light based on surface plasmon that is beneficial for generation of hot electron flows. A pulse of high kinetic energy electrons (1-3 eV), or hot electrons, in metals can be generated after surface exposure to external energy, such as in the absorption of light or in exothermic chemical processes. These energetic electrons are not at thermal equilibrium with the metal atoms. It is highly probable that the correlation between hot electron generation and surface plasmon can offer a new guide for energy conversion systems [1-3]. We show that hot electron flow is generated on the modified gold thin film (<10 nm) of metal-semiconductor (TiO2) Schottky diodes by photon absorption, which is amplified by localized surface plasmon resonance. The short-circuit photocurrent obtained with low energy photons (lower than bandgap of TiO2, ~3.1-3.2 eV) is consistent with Fowler's law, confirming the presence of hot electron flows. The morphology of the metal thin film was modified to a connected gold island structure after heating to 120, 160, 200, and 240$^{\circ}C$. These connected island structures exhibit both a significant increase in hot electron flow and a localized surface plasmon with the peak energy at 550-570 nm, which was separately characterized with UV-Vis [4]. The result indicates a strong correlation between the hot electron flow and localized surface plasmon resonance with possible application in hot electron based solar cells and photodetectors.

• 공업화학
• /
• 제28권1호
• /
• pp.35-41
• /
• 2017

외부에 노출된 재료는 자외선, 열, 온도, 습도 등의 다양한 환경 인자에 의해 성능저하가 일어나게 되며, 열화속도 및 사용수명에 대한 예측은 매우 중요한 문제이다. 본 연구에서는 가장 많이 사용되고 있는 색상 중 흰색, 초록색 재귀반사시트를 가지고 미국 아리조나, 인도 첸나이, 프랑스 세너리, 한국 서산 등 4개 지역에서 옥외폭로시험 및 제논아크촉진시험을 통하여 재귀반사시트 반사성능의 변화율을 측정하였다. 서산지역 및 제논아크 촉진시험을 통하여 얻어진 반사성능 값을 통해 회귀분석을 이용하여 가속계수를 구하였다. 또한, solar uv 프로그램을 이용하여 다양한 기후지역별 가속계수를 구할 수 있었으며, 그 결과 서산지역을 기준으로 프랑스 세너리 1.04배, 미국 아리조나 1.82배, 인도 첸나이 1.92배의 가속계수를 확인할 수 있었다.

• Clinical and Experimental Reproductive Medicine
• /
• 제43권4호
• /
• pp.207-214
• /
• 2016

Objective: This study aimed to determine the threshold of $anti-M{\ddot{u}}llerian$ hormone (AMH) as predictor of follicular growth failure in polycystic ovary syndrome (PCOS) patients treated with clomiphene citrate (CC). Methods: Fifty female subjects with PCOS were recruited and divided into two groups based on successful and unsuccessful follicular growth. Related variables such as age, infertility duration, cigarette smoking, use of Moslem hijab, sunlight exposure, fiber intake, body mass index, waist circumference, AMH level, 25-hydroxy vitamin D level, and growth of dominant follicles were obtained, assessed, and statistically analyzed. Results: The AMH levels of patients with successful follicular growth were significantly lower (p= 0.001) than those with unsuccessful follicular growth ($6.10{\pm}3.52$ vs. $10.43{\pm}4.78ng/mL$). A higher volume of fiber intake was also observed in the successful follicular growth group compared to unsuccessful follicular growth group (p= 0.001). Our study found the probability of successful follicle growth was a function of AMH level and the amount of fiber intake, expressed as Y =-2.35+($-0.312{\times}AMH\;level$)+($0.464{\times}fiber\;intake$) (area under the curve, 0.88; 95% confidence interval, 0.79-0.98; p< 0.001). Conclusion: The optimal threshold of AMH level in predicting the failure of follicle growth in patients with PCOS treated with CC was 8.58 ng/mL.

• 한국물환경학회지
• /
• 제28권5호
• /
• pp.754-761
• /
• 2012

Several drinking water treatment plants (DWTPs) produce the bottled tap waters (BTWs) as pilot production and provide them for noncommercial use. In 2008, acetaldehyde and chloral hydrate were detected in some BTWs and the public worry over the safety of the water. In this study, the BTWs produced from 7 DWTPs were tested for 13 chemicals including disinfection byproducts (DBPs). The level of four trihalomethanes (THMs) were increased up to 15 days. The average concentration of them was 0.0075 mg/L at the time of bottling and it was increased to 0.0214 mg/L after 15 days. The average acetaldehyde concentration was 0.0406 mg/L at the time of bottling but it was went up to 0.2251 mg/L after 11 days and then decreased. Although the initial concentrations of DBPs were below the drinking water standard, we also traced them at different storage conditions. Temperature affected the formations of THMs and acetaldehyde concentrations significantly. While the average concentration of THMs ranged from 0.0113 to 0.0182 mg/L at $25^{\circ}C$, it was increased to 0.0132 ~ 0.0256 mg/L at $50^{\circ}C$. In case of acetaldehyde, concentration ranged from 0.0901 to 0.2251 mg/L at $25^{\circ}C$, it was increased to 0.3394 ~ 1.0591 mg/L at $50^{\circ}C$. Throughout the tests with 7 BTWs samples, none of the chemicals was exceeded the drinking water standard of Korea. Therefore, it is recommended to avoid the exposure of BTWs to sunlight or high temperature during distribution and storage.

• 산업경영시스템학회지
• /
• 제36권3호
• /
• pp.142-149
• /
• 2013

Among ammunitions which are stored in a war field, the lifespan of propelling gunpowder is affected by storage environment such as storage temperature, humidity, and exposure to sunlight. These are because Nitrocellulose (NC) which is the main component of propelling gunpowder can be naturally disassembled to unstable substances similar with other nitric acid ester. We can't prevent it fundamentally from being disassembled, but to restrain induction of automatic disassembly by decomposition product, a decomposition product ($NO_2$, $NO_3$, and $HNO_3$) and tranquillizer DPA (Diphenylamine), having high reactivity, are added into a propellant. For this, it will decrease the velocity of tranquillizer which can also affect the velocity of producing the decomposition product of NC, storage temperature or humidity of propelling gunpowder is higher, drop of tranquillizer content is much faster. Therefore, to extend storage lifespan of propelling gunpowder, it is really important to control storage temperature or humidity inside the magazine. Hereupon, according to the manufacture of small scale model magazine and the result of performing experiments and measuring variation of inside temperature (storage temperature), using roof types that have a steel slate structure of magazine among ground magazines, this research shows the differences in details.

• 한국식품과학회지
• /
• 제10권1호
• /
• pp.46-51
• /
• 1978

황변미독(黃變米毒)의 일종인 luteoskyrin의 동정(同定) 및 정량법(定量法)을 검토한 후 변질미에서 분리된 Pen. islandicum의 luteoskyrin 생성능(生成能)을 추구한 결과는 다음과 같다. 1) Luteoskyrin은 0.5 N oxalic acid impregnated silicagel G plate로서 acetone : n-hexane : water(6:3:1.5, upper layer)를 전개용매로하는 TLC방법에서 분리(分離)가 가장 좋았다. 분리된 황색물질의 최대흡수파장(吸收波長)은 426, 448nm이었으며 chromatogram을 태양광선에 $2{\sim}3$시간 노출시 자색(紫色)으로 변하였다. 2) Luteoskyrin의 정량법으로서 TLC전개(展開)후 용출비색법(溶出比色法)에서는 4 ppm, densitometry에서는 0.1 ppm이 검출한계(檢出限界)이었다. 미곡 중의 허용량(許容量)을 3.68 ppm이하로 정설할 경우 곡류시료 중 luteoskyrin의 검색(檢索)에는 densitometry가 적합할 것이다. 3) Pen. islandicum에 의한 luteoskyrin 생성능은 Czapek 액체배지에서는 균계체(菌系體) 1g당 11mg, 가압살균한 쌀에서는 1g당 40mg이었다.

• Tribology and Lubricants
• /
• 제31권6호
• /
• pp.258-263
• /
• 2015

Biodiesel is an environmentally-friendly fuel with low smoke emission because it contains about 10% oxygen. Biodiesel fuel prepared by transesterification of vegetable oil or animal fats is susceptible to auto-oxidation. The rate of auto-oxidation depends on the number of methylene double bonds contained within the fatty acid methyl or ethyl ester groups. Biodiesel may be easily oxidized under several conditions, i.e., upon exposure to sunlight, temperature, oxygen environment. Maintenance of the fuel quality of biodiesel requires the development of technologies to increase the resistance of biodiesel to oxidation. Treatment with antioxidants is a promising approach for extending the shelf-life or storage time of biodiesel. The chemical properties of various amine-based antioxidants were evaluated after synthesis of the antioxidants by condensation of phenylenediamine with alkylamines at room temperature. In general, the oxidative stability can be assessed based on various experimental parameters. Such parameters may include temperature, pressure, and the flow rate of air through the samples. The Rancimat method (EN14112) was selected because it is a rapid technique that requires very little sample and provides good precision for oxidative degradation analysis. Specifically, the EN 14112 technique provides enhanced efficiency for oxidative stability evaluation when a larger ester head group is utilized. Therefore, this technique was employed for evaluation of the oxidation stability of biodiesel by the Rancimat method (EN14112).

• 원예과학기술지
• /
• 제34권1호
• /
• pp.32-45
• /
• 2016

Fruit bagging has been widely practiced in peach cultivation to produce high quality and unblemished fruit. Moreover, fruit bagging has been utilized to study the effect of shading on the quality of fruit. We conducted a proteomic analysis on peach fruit to elucidate the biochemical and physiological events that characterize the effect of bagging treatment. Comparative analysis of 2D electrophoresis (2-DE) gels showed that relative protein levels differed significantly at 125 DAFB (days after full bloom), as well as at 133 DAFB in fruit that had been bagged until 125 DAFB, followed by exposure to sunlight. Most of the proteins with altered expression were identified by MALDI TOF/TOF. Twenty-one proteins with differential expression among the groups were identified at 125 DAFB, while thirty proteins with differential expression among the groups were identified at 133 DAFB. The analysis revealed that expression of proteins involved in photosynthesis, stress responses, and biochemical processes influencing metabolism were altered during bagging treatment, suggesting that regulation of the synthesis of carbohydrates, amino acids, and proteins influenced fruit size, solid/acid ratio, and peel color. This work provides the first characterization of proteomic changes in peach in response to fruit bagging treatment. Identifying and tracking protein changes may allow us to better understand the mechanisms underlying the effects of bagging treatment.

• Molecules and Cells
• /
• 제42권2호
• /
• pp.151-160
• /
• 2019

Ultraviolet (UV) radiation of the sunlight, especially UVA and UVB, is the primary environmental cause of skin damage, including topical inflammation, premature skin aging, and skin cancer. Previous reports show that activation of nuclear $factor-{\kappa}B$ ($NF-{\kappa}B$) in human skin fibroblasts and keratinocytes after UV exposure induces the expression and release of proinflammatory cytokines, such as interleukin-1 (IL-1) and tumor necrosis $factor-{\alpha}$ ($TNF-{\alpha}$), and subsequently leads to the production of matrix metalloproteases (MMPs) and growth factor basic fibroblast growth factor (bFGF). Here, we demonstrated that TNFR2-SKEE and TNFR2-SKE, oligopeptides from TNF receptor-associated factor 2 (TRAF2)-binding site of TNF receptor 2 (TNFR2), strongly inhibited the interaction of TNFR1 as well as TNFR2 with TRAF2. In particular, TNFR2-SKE suppressed UVB- or $TNF-{\alpha}$-induced nuclear translocalization of activated $NF-{\kappa}B$ in mouse fibroblasts. It decreased the expression of bFGF, MMPs, and COX2, which were upregulated by $TNF-{\alpha}$, and increased procollagen production, which was reduced by $TNF-{\alpha}$. Furthermore, TNFR2-SKE inhibited the UVB-induced proliferation of keratinocytes and melanocytes in the mouse skin and the infiltration of immune cells into inflamed tissues. These results suggest that TNFR2-SKE may possess the clinical potency to alleviate UV-induced photoaging in human skin.