• Title/Summary/Keyword: Ultra Violet

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Sterilization of Escherichia coli Based on Nd: YAG Resonator with a Pulsed Xenon Flashlamp

  • Kim, Hee-Je;Kim, Dong-Jo;Hong, Ji-Tae;Xu, Guo-Cheng;Lee, Dong-Gil
    • Journal of Electrical Engineering and Technology
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    • v.6 no.2
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    • pp.275-279
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    • 2011
  • Sterilization of Escherichia coli (E. coli) is examined using a unique pulsed ultra-violet (UV) elliptical reactor based on Nd:YAG laser resonator, UV radiation from a pulsed xenon flashlamp. The light from the discharge has a broadband emission spectrum extending from the UV to the infrared region with a rich UV contained. Sterilization method by using the UV light is fast, environment-friendly and it does not cause secondary pollution. A Nd:YAG laser resonator having elliptical shape has advantage of concentrating the radiation of the UV light at two foci as the quart sleeve filled with E. coli. The primary objective of this research is to determine the important parameters such as pulse per second (pps), the applied voltage for sterilizing E. coli by using an UV elliptical reactor. From the experiment result, the sterilization effect of UV elliptical reactor is better than that of UV cylindrical reactor, and it can be 99.9% of sterilization at 800V regardless of the pps within 10 minutes.

Combination of Light Emitting Diode at 375 nm and Photo-reactive TiO2 Layer Prepared by Electrostatic Spraying for Sterilization

  • Hwang, Kyu-Seog;Jeon, Young-Sun;Choi, Tae-Il;Hwangbo, Seung
    • Journal of Electrical Engineering and Technology
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    • v.8 no.5
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    • pp.1169-1174
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    • 2013
  • The objective of this work was to increase the efficiency of ultraviolet-light emitting diodes at 375 nm for sterilization. Since $TiO_2$ had antibacterial properties, which were attributed to the appearance of hydroxyl radicals and superoxide radical anions on the surface species under ultra violet radiation at about 387 nm, photo-reactive layers such as Ag-doped $TiO_2$ were coated on aluminum substrates by electrostatic spraying. Crystallinity and surface morphology of the coating layer were examined by X-ray diffraction ${\theta}-2{\theta}$ scan and field emission-scanning electron microscope, respectively. In an antibacterial test, we observed above 99% reduction of Escherichia coli populations on 3 or 5 mol% Ag-doped $TiO_2$ layers after irradiation for 2 hrs at 375 nm, while very low inactivation on bare aluminum substrates occurred after irradiation as the same condition.

Cloning and Characterization of UV-B Inducible Chalcone Synthase from Grape Cell Suspension Culture System and Its Expression Compared with Stilbene Synthase

  • Song, Won-Yong;In, Jun-Gyo;Lim, Yong-Pyo;Park, Kwan-Sam
    • Journal of Photoscience
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    • v.7 no.2
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    • pp.53-58
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    • 2000
  • We performed the cloning of a chalcone synthase (CHS) gene, the key enzyme in the anthocyanin biosynthesis, from the cDNA library constructed with grape suspension cells irradiated UV-B. The PCR fragment was used to cloning the CHS gene. One CHS cDNA clone containing an open reading frame and a partial stilbene synthase (STS)cDNA, the stilbene-type phytoalexin, were isolated. The CHS cDNA clone (VCHS) showed 87% sequence homology with VvCHS (V.vinifea) and 72.3% identity with VSTSY(V.vinifea). its amino acid sequences were longer than any other CHS genes as 454 residues. Two genes were weakly expressed in white light irradiated cells, but highly induced in UV-B irradiated condition during 32 hours. Interestingly, the STS was quickly and abundantly expressed from 2 hours when supplemented with jasmonic acid (JA) and the maximum expression was observed at 4 hours and then gradually decreased. But, the additional UV-B or white light quickly degraded the STS expression than only JA treated grape suspension cells. The CHS also was rapidly induced with JA and the synergistical effect was observed at the addigional light treatment of UV-B or white light. These results are indicated that CHS and STS have different response mechanisms against the environmental stresses.

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Development of a Candidate Equipment for Ozone SRP and its Uncertainty Evaluation (오존 SRP의 제작과 측정 불확도 평가)

  • 정규백;우진춘;이진홍
    • Journal of Korean Society for Atmospheric Environment
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    • v.17 no.4
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    • pp.313-319
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    • 2001
  • The development of ozone SRP (Standard Reference Photometer) designated as a G-7 project by the Korean Ministry of Environment began 1997 and is now nearly completed. With the completion of the ozone SRP we will not only acquire a qualification to participate in the international ozone calibration system but also enhance calibration credibility of ozone similarly to that of other ambient air pollution monitors. As the ozone SRP uses highly cleaned blank air that can be distinguished from general ozone analyzer, it is possible to reduce errors associated with the determination of ozone via elongation of the absorption length as long as 1 meter In addition, gas chopping method hat been adopted to cut down interference of other substances and time drift. Furthermore, the system has also been modified to minimize the strayed ultra-violet noise along the light path. In this paper, a new method for uncertainty evaluation has been introduced, which is guided by the ISO (International Standard Organization) GUM (Guide to the Expression of Uncertainty in Measurement) through assessments of the uncertainty type B (that was impossible to estimate before) as well as the uncertainty type A (based on statistics).

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Protective Effect of Gryllus Bimaculatus Methanol Extract on UVB-induced Photoaging in Human Skin Fibroblasts (UVB로 손상된 피부 섬유아세포에서 쌍별귀뚜라미 메탄올 추출물의 보호효과)

  • Jeong, Taekyoung;Yu, Myeongnam;Heo, Huijin;Yang, Jinwoo;Jeong, Heonsang;Lee, Junsoo
    • Journal of the Korean Society of Food Culture
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    • v.35 no.5
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    • pp.478-482
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    • 2020
  • We evaluated the protective effects of cricket methanol extract (CME) on ultra-violet B (UVB)-induced photoaging in human skin fibroblasts. The fibroblast cells were treated with 10, 50, and 100 ㎍/mL of CME for 24 h, and then exposed to UVB (30 mJ/㎠). CME showed a dose-dependent cytoprotective effect without any observable cytotoxicity. CME reduced UVB-induced production of reactive oxygen species (ROS) by 34.4, 34.9, 40.6% at concentrations of 10, 50, 100 ㎍/mL respectively. CME inhibited the release of matrix metalloproteinase (MMP) 1 and 3. Furthermore, CME also reduced UVB-induced collagen degradation in the fibroblast cells. Taken together, our data suggests that CME has a significant protective effect on UVB-induced photoaging of the skin. This benefit occurs through multiple mechanisms. The results also suggest a potential role for CME as an ingredient in anti-photoaging cosmetic products in the future.

Effect of Some Factors on the Production of an Antifungal Compound KRF-001 from Bacillus subtilis subsp. krictiensis (Bacillus subtilis subsp. krictiensis로부터 항진균물질 KRF-001의 생산을 위한 발효조건 및 돌연변이 연구)

  • 손광희;권혜경;복성해;이항우
    • Microbiology and Biotechnology Letters
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    • v.19 no.6
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    • pp.614-618
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    • 1991
  • Antifungal compound, KRF-001, was produced by Bacillus subtilis subsp. krictiensis isolated from soil. Physico-chemical factors affecting cell growth and bioactivity were examined to improve the production yield. Nutrient composition, temperature, pH and phosphate ion concentration were proved to be important factors for the production of KRF-001. Mutation was performed to select high yielding strains. First, mutation was performed with ultra-violet light, and the second mutation process was conducted by MNNG (N-Methyl-N'-nitro-N-nitrosoguanidine) resulting in three high yielding strains.

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Effects of titanium oxide nanoparticles on Oryzias latipes embryos and sac-fry under different irradiation conditions

  • Nam, Sun-Hwa;Shin, Yu-Jin;An, Youn-Joo
    • Environmental Engineering Research
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    • v.22 no.4
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    • pp.426-431
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    • 2017
  • Some phototoxicity of titanium dioxide nanoparticles ($TiO_2$ NPs) has been reported in recent years in studies with fish embryos or larvae. However, it is necessary to focus on the potential effects of embryonic exposure due to irreversible abnormalities and mortalities observed in sac-fry, and to expand various fish embryos to generate multiple test species. The aim of this study was to evaluate the effects of $TiO_2$ NPs under different irradiation conditions in exposed Oryzias latipes (O. latipes) at the embryonic and sac-fry stages. The effects of different irradiation conditions were observed using ultra-violet (UV) and visible light, and the corresponding effects were monitored by determining cumulative mortality and abnormality. O. latipes were exposed for 8 d to 0, 1, 5, 10, or 50 mg/L $TiO_2$ NPs under UV ($4,818.86mW/m^2$ at the bottom of clear vials) or visible light, after which the embryos were transferred to NP-free embryo-rearing solution until 16 days post fertilization (dpf). Abnormalities of embryos and sac-fry increased at high $TiO_2$ NP concentrations under UV irradiation, compared to control samples treated with visible light or UV irradiation alone. This work provides information regarding the phototoxicity of $TiO_2$ NPs using O. latipes at the embryonic and sac-fry stages.

A study on Amine Synergist Effect in UV Curing System (UV 경화 시스템에서 Amine Synergist의 효과에 대한 연구)

  • Kim, Ji-Cheol;Moon, Seok-Young
    • Journal of the Korean Graphic Arts Communication Society
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    • v.22 no.1
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    • pp.29-38
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    • 2004
  • With increasing interests in environment matters over the world, incessant efforts to develop products which meet these environmental requirements have been made also in paint industry. Among the efforts in this field, UV(Ultra Violet) curing system is focused as one of most potential system. It is because this system not only proved to be environmentally friendly compared with heat curing system or other system but also has economical merit of smaller facility, less energy consumption, and better productivity. Superior properties in many application is surely one of its dominant merit. With these advantage UV system is applied to a variety of industrial fields and expected to have continuous growth in the future. As practical application of UV system has shown lasting progress, R&D on basic material of this system keeps up with. This is a study on photo-initiator that is a fundamental substance in UV curing method and amine, its aid for better effect. After reviewing on them in the aspects of function, economy, and stability, optimal foumula is pursued through experiments when applied to real products.

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A Retrieval of Vertically-Resolved Asian Dust Concentration from Quartz Channel Measurements of Raman Lidar (라만 라이다의 석영 채널을 이용한 고도별 황사 농도 산출)

  • Noh, Young-Min;Lee, Kwon-Ho;Lee, Han-Lim
    • Journal of Korean Society for Atmospheric Environment
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    • v.27 no.3
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    • pp.326-336
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    • 2011
  • The Light Detection and Ranging (Lidar) observation provides a specific knowledge of the temporal and vertical distribution and the optical properties of the aerosols. Unlike typical Mie scattering Lidars, which can measure backscattering and depolarization, the Raman Lidar can measure the quartz signal at the ultra violet (360 nm) and the visible (546 nm) wavelengths. In this work, we developed a method for estimating mineral quartz concentration immersed in Asian dust using Raman scattering of quartz (silicon dioxide, silica). During the Asian dust period of March 15, 16, and 21 in 2010, Raman lidar measurements detected the presence of quartz, and successfully showed the vertical profile of the dust concentrations. The satellite observations such as the Moderate Resolution Imaging Spectroradiometer (MODIS) and the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) confirmed spatial distribution of Asian dust. This approach will be useful for characterizing the quartz dominated in the atmospheric aerosols and the investigations of mineral dust. It will be especially applicable for distinguishing the dust and non-dust aerosols in studies on the mixing state of Asian aerosols. Additionally, the presented method combined with satellite observations is enable qualitative and quantitative monitoring for Asian dust.

A Trend of the National and International Standards for Fluorescent Induction Lamps (무전극 형광램프 국내외 표준화 동향)

  • Cho, M.R.;Shin, S.W.;Lee, S.H.;Hwang, M.K.;Lee, D.Y.;Yang, S.Y.;Ham, J.K.
    • Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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    • 2007.05a
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    • pp.145-147
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    • 2007
  • Fluorescent induction lamps are assembly of a Low Pressure Mercury discharge vessel and an inductive power coupler. A vessel containing at least a Low Pressure Mercury vapor, which will be energized by means of the Inductive Coupler. The Ultra Violet radiation from the resulting discharge is converted by a layer of fluorescent material into visible light. The discharge vessel may have means of mechanical fixation to position it to the Inductive power coupler. The component to transform High Frequency electrical energy, by means of induction, in order to energize the Low Pressure Mercury in the discharge vessel. The component includes electrical connection. Fluorescent induction lamps don't have international standards yet. So we try to correspond Korea standards to international standards.

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