• Title/Summary/Keyword: Ionizing

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Remediation effect of indoor airborne fungi by operating the ionizing air cleaner in the university office.

  • Heo, S.M.;Song, J.H.;Paik, N.W.
    • Proceedings of the Korean Environmental Health Society Conference
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    • 2003.06a
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    • pp.181-182
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    • 2003
  • Our study from Feburary to March, 2003, were done in university office A and B, located in Seoul. This study was carried out to investigate the reduction of the airborne fungi before and after we activate the air cleaner which using ionization. And the method of assessment was done by the CAMNEA method. The result was as follows. 1. In the research office A, the concentration of the airborne fungi was 18(${\pm}$11.3) CFU/㎥ before the ionizing air cleaner system was turned on: whereas three days after this result the concentration decreased to less than 1 CFU/㎥. 2. In the laboratory office B, the concentration was 210.6(${\pm}$5.3) CFU/㎥ before using the air cleaner and was decreased to 32.2(t 10.3) CFU/㎥ after using the air cleaner. The remediation rate in the experiment was 85 percentile,

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Concepts, Quantities, Units and Terminology for Non-ionizing Radiation (비이온화방사선에 대한 제반 개념 양, 단위 및 용어)

  • Lee, Soo-Yong
    • Journal of Radiation Protection and Research
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    • v.20 no.3
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    • pp.201-213
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    • 1995
  • Protection against non-ionizing radiation(NIR) is the subject of an increasing interest but the use of very different concepts depending on the type of radiation or application, makes it rather difficult to compile studies and the data obtained in an uniformity in this field. The main object of the present paper is to summarizes and provide an inventory of concepts, quantities, units and terminology currently used for purposes of NIR protection. Furthermore a systematic classification and comparison of these quantities is given, and in particular the concepts used to quantify exposure limitation and radiation protection standards are summarized and discussed.

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Resveratrol and piperine enhance radiosensitivity of tumor cells

  • Tak, Jean-Kyoung;Lee, Jun-Ho;Park, Jeen-Woo
    • BMB Reports
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    • v.45 no.4
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    • pp.242-246
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    • 2012
  • The use of ionizing radiation (IR) is essential for treating many human cancers. However, radioresistance markedly impairs the efficacy of tumor radiotherapy. IR enhances the production of reactive oxygen species (ROS) in a variety of cells which are determinant components in the induction of apoptosis. Much interest has developed to augment the effect of radiation in tumors by combining it with radiosensitizers to improve the therapeutic ratio. In the current study, the radiosensitizing effects of resveratrol and piperine on cancer cells were evaluated. Cancer cell lines treated with these natural products exhibited significantly augmented IR-induced apoptosis and loss of mitochondrial membrane potential, presumably through enhanced ROS generation. Applying natural products as sensitizers for IR-induced apoptotic cell death offers a promising therapeutic approach to treat cancer.

Effects of Ionizing Energy on Some Physico-Chemical Properties of Chestnut Starch (밤 전분의 성질에 대한 전리에너지의 영향)

  • Kwon, Joong-Ho;Park, Sun-Hee;Kim, Sung-Kon
    • Korean Journal of Food Science and Technology
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    • v.25 no.1
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    • pp.83-85
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    • 1993
  • Some properties of starch isolated from gamma-irradiated chestnut at doses of $0{\sim}0.45\;kGy$ were investigated. The treatment increased the water-binding capacity and decreased intrinsic viscosity and amlyograph viscosities. Other properties including swelling power and solubility at $80^{\circ}C$, blue value and percent transmittance of starch dispersion were essentially not affected by irradiation at sprout-inhibition dose.

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Characteristics of Specific Absorption Rate (SAR) in Electromagnetic (EM) Dosimetry

  • Hwang, Sun-Tae;Choi, Kil-Oung
    • Journal of Radiation Protection and Research
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    • v.25 no.2
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    • pp.109-114
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    • 2000
  • The SI unit of specific absorption rate (SAR) in W/kg in the electromagnetic (EM) field as non-ionizing radiation is exactly same as the SI unit of absorbed dose rate in Gy/s in the ionizing radiation field. The SI unit of both physical quantities can be expressed in $[m^{\cdot}s^{-3}]$. Where, the unit of absorbed dose, Gy stands for Gray. In EM biological interactions, the SAR equations are derived and the characteristics of EM field energy absorption in terms of the SAR are discussed and described on the mathematical basis.

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Proton and γ-ray Induced Radiation Effects on 1 Gbit LPDDR SDRAM Fabricated on Epitaxial Wafer for Space Applications

  • Park, Mi Young;Chae, Jang-Soo;Lee, Chol;Lee, Jungsu;Shin, Im Hyu;Kim, Ji Eun
    • Journal of Astronomy and Space Sciences
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    • v.33 no.3
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    • pp.229-236
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    • 2016
  • We present proton-induced single event effects (SEEs) and γ-ray-induced total ionizing dose (TID) data for 1 Gbit lowpower double data rate synchronous dynamic random access memory (LPDDR SDRAM) fabricated on a 5 μm epitaxial layer (54 nm complementary metal-oxide-semiconductor (CMOS) technology). We compare our radiation tolerance data for LPDDR SDRAM with those of general DDR SDRAM. The data confirms that our devices under test (DUTs) are potential candidates for space flight applications.

Improving the Food Safety of Seed Sprouts Through Irradiation Treatment

  • Waje, Catherine;Kwon, Joong-Ho
    • Food Science and Biotechnology
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    • v.16 no.2
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    • pp.171-176
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    • 2007
  • Fresh sprouts such as alfalfa, mung bean, radish, broccoli, and soybean sprouts have become very popular due do their high nutritional value. However, there have been several outbreaks of illness in the last few years that have been attributed to sprout consumption. A number of methods have been used to improve the safety of seed sprouts. One promising technology is the use of ionizing radiation treatment. Irradiation with doses up to 8 kGy has been approved in the USA to control microbial pathogens in seeds intended for sprout production. This review focuses on the potential use of ionizing radiation in reducing the pathogen levels in seed sprouts. The effects of irradiation on seed germination and the nutritional quality of the sprouts are discussed.

Correlation of the Rates of Solvolysis of t-Butyl Fluoroformate Using the Extended Grunwald-Winstein Equation

  • Lee, Yong-Woo;Seong, Mi-Hye;Kyong, Jin Burm;Kevill, Dennis N.
    • Bulletin of the Korean Chemical Society
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    • v.31 no.11
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    • pp.3366-3370
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    • 2010
  • The specific rates of solvolysis of t-butyl fluoroformate (1) have been measured at $40.0^{\circ}C$ in 21 pure and binary solvents. These give a satisfactory correlation over the full range of solvents when the extended Grunwald-Winstein equation, with incorporation of the solvent nucleophilicity and the solvent ionizing power, is applied. The actual values are very similar to those obtained in earlier studies of the solvolyses of isopropyl chloroformate and ethyl chlorothioformate in the more ionizing and least nucleophilic solvents, which are believed to proceed by an ionization pathway. The small negative values for the entropies of activation are consistent with the ionization nature of the proposed rate-determining step. These observations are also compared with those previously reported for the corresponding primary and secondary alkyl haloformate esters.