• Title, Summary, Keyword: irradiation

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Effect of γ-Irradiation on the Molecular Properties of Myoglobin

  • Lee, Yong-Woo;Song, Kyung-Bin
    • BMB Reports
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    • v.35 no.6
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    • pp.590-594
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    • 2002
  • To elucidate the effect of gamma-irradiation on the molecular properties of myoglobin, the secondary and tertiary structures, as well as the molecular weight size of the protein, were examined after irradiation at various irradiation doses. Gamma-irradiation of myoglobin solutions caused the disruption of the ordered structure of the protein molecules, as well as degradation, cross-linking, and aggregation of the polypeptide chains. A SDS-PAGE study indicated that irradiation caused initial fragmentation of the proteins and subsequent aggregation, due to cross-linking of the protein molecules. The effect of irradiation on the protein was more significant at lower protein concentrations. Ascorbic acid protected against the degradation and aggregation of proteins by scavenging oxygen radicals that are produced by irradiation. A circular dichroism study showed that an increase of the irradiation decreased the a-helical content of myoglobin with a concurrent increase of the aperiodic structure content. Fluorescence spectroscopy indicated that irradiation increased the emission intensity that was excited at 280 nm.

Irradiation and Power Analysis According to Seasons (태양광 시스템의 계절별 일사량과 전력량)

  • Li, Ying;Jung, Jong-Chul;Choi, Yong-Sung;Lee, Kyung-Sup
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • pp.220-220
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    • 2009
  • In case of favourable irradiation conditions, the ratio of irradiation to the total irradiation went up and then the irradiation increased in the area with high angle of inclination. The study showed that on a clear day with the irradiation of more than $800[W/m^2]$, the pattern of alternating current power change in the fixed system was similar with that in the single-axis tracker. On the contrary, in case of unfavourable irradiation conditions, the ratio of diffuse irradiation to the total irradiation went up and then the horizontal irradiation increased. In the demo system, the fixed system, the single-axis tracker and the dual-axis tracker all had low generation power and similar generation pattern with each other. The study showed the generation power varied with the irradiation in the fixed system, while in the single-axis tracker and the dual-axis tracker, the amount of the generation power variation was much more than the irradiation variation. The demo system was operated from 11:00 AM to 2:00 PM for generating power, during which time, 46[%] to 56[%] of the total generation power was produced. In this study. the generation power was increased by 147[%] in the fixed system, by 136[%] in the single-axis tracker, and by 164[%] in the dual-axis tracker, and the pattern of generation power was similar with the generation power variation in the situation where the irradiation increased by 140[%] in the spring with plenty of insolation. The alternating current power was more sensitive to variation of the irradiation than to that of the surface temperature of a module. The variation of the irradiation had a more positive effect on the generation power than the type of array.

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Short Communication of Novel Application of Food Irradiation

  • Cheorun Jo;Lee, Ju-Wosn;Byunl, Myung-Woo
    • Preventive Nutrition and Food Science
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    • v.6 no.4
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    • pp.253-256
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    • 2001
  • Irradiation of food is not only used for sanitation purposes but can be used for processing techniques to reduce or eliminate toxic or undesirable compounds on food. Irradiation wag effective to reduce the allergenicity of food by modification of the structure of proteins causing allergy reactions. Volatile N-nitrosmaine was reduced or eliminated by irradiation in the model system study and the breakdown products by irradiation did not recombine under human stomach conditions (pH 2,3, and 4,37$^{\circ}C$). The possibility of residual chlorophyll b reduction by irradiation was also found, and the model study indicated that irradiation be used to destroy chlorophyll b, resulting in protection from photooxidation in oil without acceleration of lipid oxidation during irradiation. In this paper, several on-going research projects for the application of food irradiation as a new processing technique are introduced, including reduction of food allergens, breakdown of volatile N-nitrosamine and residual chlorophyll b.

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Power Pattern Analysis According to Irradiation for Photovoltaic Systems (태양광 발전시스템의 일사량에 따른 전력 패턴 분석)

  • Park, Sang-Jun;Kim, Hyeong-Seok;Choi, Yong-Sung;Lee, Kyung-Sup
    • Proceedings of the KIEE Conference
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    • pp.46-48
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    • 2009
  • This paper aims to investigate generation conditions necessary for the most efficient generation by measuring electricity power under various irradiation conditions, since the photovoltaic generation system has high costs and low efficiency. In addition, because the irradiation varies hourly, daily, monthly, and yearly, the research on the irradiation necessary for photovoltaic generation was carried out by analyzing the pattern o( Bower under various irradiation conditions. Also, after measuring the daily variations of irradiation and generation power, the monthly accumulated irradiation and monthly accumulate power which had the most generation power were investigated and the pattern of the annual generation power was analyzed. The results of this study are as follows. As for the relationship between the photovoltaic generation system and the irradiation, the generation power increased with the irradiation and when the irradiation was more than 600 $[W/m^2]$ the generation power amounted to more than 100 [Wh] as the resonable result.

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CONTRIBUTION OF HANARO IRRADIATION TECHNOLOGIES TO NATIONAL NUCLEAR R&D

  • Choo, Kee Nam;Cho, Man Soon;Yang, Sung Woo;Park, Sang Jun
    • Nuclear Engineering and Technology
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    • v.46 no.4
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    • pp.501-512
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    • 2014
  • HANARO is a multipurpose research reactor located at the Korea Atomic Energy Research Institute (KAERI). Since the commencement of its operation in 1995, various neutron irradiation facilities, such as rabbit irradiation facilities, fuel test loop (FTL) facilities, capsule irradiation facilities, and neutron transmutation doping (NTD) facilities, have been developed and actively utilized for various nuclear material irradiation tests requested by users from research institutes, universities, and industries. Most irradiation tests have been related to national R&D relevant to present nuclear power reactors such as the ageing management and safety evaluation of the components. Based on the accumulated experience as well as the sophisticated requirements of users, HANARO has recently supported national R&D projects relevant to new nuclear systems including the System-integrated Modular Advanced Reactor (SMART), research reactors, and future nuclear systems. This paper documents the current state and utilization of irradiation facilities in HANARO, and summarizes ongoing research efforts to deploy advanced irradiation technology.

Alterations in Seed Vigour and Viability of Soybean Related with Accelerated Seed Aging and Low Dose Gamma Irradiation

  • Hwangbo, Jun-Kwon;Kim, Jae-Sung;Lim, Ji-Hyeok;Baek, Myung-Hwa;Chung, Byung-Yeoup
    • KOREAN JOURNAL OF CROP SCIENCE
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    • v.48 no.4
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    • pp.334-338
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    • 2003
  • The objective of this study was to demonstrate whether or not the deleterious effects of accelerated aging on seed vigour and viability are alleviated by interaction with gamma irradiation. Seeds of soybean (Glycine max L.) were artificially aged and subsequently irradiated with 4 and 8 Gy of gamma irradiation. Germination rate was negatively affected by accelerated aging and positively by gamma irradiation, with a positive interaction of a 3day-seed aging treatment occurring with 4 Gy, possibly suggesting that 4 Gy of gamma irradiation partially offset the adverse effects of seed aging on germination. However, 5-day aged seeds did not gain any benefits from the gamma irradiation. Electrolyte leakage from the seeds increased with the duration in days aged. Irradiation, however, did not impose any effects on the leakage. Respiration rate of the seed with hypocotyl and primary root was significantly low for the aged seeds, but not for the seeds with both irradiation and aging treatments. Accelerated aging decreased the dry weight of the hypocotyl and primary root of the seeds without any measurable effects of irradiation. $\alpha$-Amylase activity decreased with seed aging and positively responded to gamma irradiation. The data is discussed with regard to the possible roles of gamma irradiation for improving the seed vigour and viability of aged seeds.

The Effect of Gamma Irradiation on PLGA and Release Behavior of BCNU from PLGA Wafer

  • Lee, Jin-Soo;Chae, Gang-Soo;Gilson Khang;Kim, Moon-Suk;Cho, Sun-Hang;Lee, Hai-Bang
    • Macromolecular research
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    • v.11 no.5
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    • pp.352-356
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    • 2003
  • The objectives of this study were to investigate the influence of gamma irradiation for sterilization on poly(D,L-lactide-co-glycolide) (PLGA) with different molecular weight and the effect of gamma irradiation on the release behavior of 1,3-bis(2-chloroethyl)-1-nitrosourea (BCNU, carmustine) from PLGA wafer with various irradiation doses. The effect of gamma irradiation on PLGA was evaluated by gel permeation chromatography (GPC), differential scanning calorimetry (DSC), and electron paramagnetic resonance (EPR). The weight average molecular weight (M$_{w}$) and glass transition temperature (T$_{g}$) of PLGA decreased after gamma irradiation. The extent of M$_{w}$ reduction was dependent on irradiation dose and PLGA molecular weight. Using EPR spectroscopy, we successfully detected gamma irradiation induced free radicals in PLGA. The gamma irradiation increased the release rate of BCNU from PLGA wafer at applied irradiation doses except 2.5 Mrad of irradiation dose in this study.study.

Analysis of Irradiation and Power per Each Seasons of Photovoltaic Systems (태양광 발전시스템의 계절별 일사량과 전력량 분석)

  • Kim, Seok-Gon;Hwang, Jun-Won;Lee, Ying;Choi, Yong-Sung;Lee, Kyung-Sup
    • Proceedings of the KIEE Conference
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    • pp.43-45
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    • 2009
  • In case of favourable irradiation conditions, the ratio of irradiation to the total irradiation went up and then the irradiation increased in the area with high angle of inclination. The study showed that on a clear day with the irradiation of more than 80$[W/m^2]$, the pattern of alternating current power change in the fixed system was similar with that in the single-axis tracker. On the contrary, in case of unfavourable irradiation conditions, the ratio of diffuse irradiation to the total irradiation went up and then the horizontal irradiation increased. In the demo system, the fixed system, the single-axis tracker and the dual-axis tracker all had low generation power and similar generation pattern with each other. The study showed the generation power varied with the irradiation in the fixed system, while in the single-axis tracker and the dual-axis tracker, the amount of the generation Power variation was much more than the irradiation variation. The demo system was operated from 11:00 AM to 2:00 PM for generating power, during which time, 46[%] to 56[%] of the total generation power was produced. In this study, the generation power was increased by 147[%] in the fixed system, by 136[%] in the single-axis tracker, and by 164[%] in the dual-axis tracker, and the pattern of generation power was similar with the generation power variation in the situation where the irradiation increased by 140[%] in the spring with plenty of insolation. The alternating current power was more sensitive to variation of the irradiation than to that of the surface temperature of a module. The variation of the irradiation had a more positive effect on the generation power than the type of array.

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Effect of γ-Irradiation on the Physicochemical Properties of Zein Films

  • Lee, Sehee;Lee, Myoungsuk;Song, Kyung-Bin
    • Preventive Nutrition and Food Science
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    • v.8 no.4
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    • pp.343-348
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    • 2003
  • To elucidate the effect of gamma-irradiation on the physicochemical properties of zein films, the molecular and mechanical properties of the films were examined after irradiation at various irradiation doses. Gamma-irradiation of zein solutions caused the disruption of the ordered structure of the zein molecules, as well as degradation, cross-linking, and aggregation of the polypeptide chains based on an SDS-PAGE study. Gamma-irradiation increased the solubility of zein and decreased the viscosity due to cleavage of the polypeptide chains. Protein solubility of the zein films in urea/2-mercaptoethanol also increased with increasing irradiation doses. Alterations of the zein molecules by irradiation decreased water vapor per-meability by 12% and increased the elongation of zein films. However, mean tensile strength of the zein films was decreased by gamma-irradiation treatment. Measurement of Hunter color values indicated that irradiation caused a destructive effect on yellow pigments, resulting in a significant decrease in Hunter b values. The microstructure as observed by scanning electron microscopy showed that irradiated zein film had a smoother and glossier surface than the non-irradiated films.

Advances in Food Irradiation and It's Potential Roles in Korea (한국에 있어서 식품조사 기술의 진보와 식품산업에서의 역할)

  • 권중호
    • Proceedings of the Korean Society of Food Hygiene and Safety Conference
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    • pp.35-49
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    • 1994
  • Based on the safety of irradiated foods which was demonstrated from the toxicological, microbiological and nutritional points of view, irradiation has been identified as a viable technology for food preservation and processing, having a potential both of reducing storage losses by controlling spoilage organisms, sprouting and ripening, and of improving hygienic quality of raw and processed products. Research and development over decades in the field of food irradiation have led to the regulatory approval in 37 countries and of them 25 countries including Korea are commercially utilizing food irradiation process. Although progress towards acceptance of food irradiation by the industry is slow, actual market trials have shown that once consumers have understood this technology, they are willing to buy irradiated foods. Considering recent advances in food irradiation and restrictions in the use of chemical fumigants, it is expected that food irradiation is in the process of "taking off". This paper deals with up-to-date progress in food irradiation with particular reference to domestic activities in legislation, consumer perception, commercialization, and potential applications in the food industry.

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