• Preventive Nutrition and Food Science
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• 제11권2호
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• pp.146-154
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• 2006

Structural modification of corn starch by gamma irradiation was evaluated for under dry conditions at varied intensities from 0 to 40 kGy. Under scanning electron microscopy, the granule shape of corn starch was not significantly affected by the irradiation up to 40 kGy. In addition, X-ray diffraction and melting patterns of the irradiated starches were similar to those of the native starch, indicating that crystalline regions in the starch granules were not changed by irradiation. However, the pattern of gel permeation column chromatography showed a significant increase in partial hydrolysis of gamma irradiated starch samples. The degree of polymerization and the paste viscosity of irradiated starch samples dose-dependently decreased significantly with irradiation, and increased solubility and clarity were observed in the irradiated starch solution. In addition, the degree of retrogradation decreased as irradiation dose increased. Irradiation of corn starch has advantages over the ordinary acid or the enzyme hydrolysis modification methods. It does not affect the granular shape and crystalline phase of starch during hydrolysis, and the process can be carried out in dry state.

• 생약학회지
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• 제36권2호통권141호
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• pp.75-80
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• 2005

This study is concerning to identify the hygienic problems occurring in processing, storage, and distribution of Rehmanniae radix crude, and to investigate the possibility of application of safe and hygienic ${\gamma}-irradiation$ techniques. The results are as follows. To compare the contents of catapol, index compound of Rehmanniae Radix crude, between before and after ${\gamma}-irradiated$,0,2.5,5,7.5,10,12.5,15,20, and 30 kGy of ${\gamma}-irradiation$ was applied to standard catapol and Rehmanniae radix crude. The contents of catapol in standard material and Rehmanniae radix crude were decreased with the increase of ${\gamma}-irradiation$ level. However, active components of Rehmanniae Radix crude were not changed with ${\gamma}-irradiation$. These results indicate that active components of Rehmanniae Radix crude were preserved after ${\gamma}-irradiation$ and those of Rehmanniae Radix crude did not showed significant change after irradiation of ${\gamma}-ray$ up to 20 kGy.

• 식물병연구
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• 제21권3호
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• pp.193-200
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• 2015

Gray mold caused by Botrytis cinerea is one of the most important postharvest fungal pathogens of cut flowers. Here, gamma irradiation, an alternative for phytosanitary purposes, and sodium dichloroisocyanurate (NaDCC) were used to control B. cinerea in a cut chrysanthemum (Chrysanthemum morifolium Ramat.) cultivar, 'Baekma', one of the cultivars susceptible to B. cinerea. Spore germination and mycelium growth of B. cinerea were inhibited by gamma irradiation in an inversely dose-dependent manner. A dose of 4 kGy completely inhibited the mycelium growth of B. cinerea. A significant change in flower quality (physical properties) on chrysanthemum was shown from gamma irradiation at over 0.2 kGy (p<0.05). Therefore, in this study, the integration of gamma ray (below 0.2 kGy) and NaDCC, an eco-friendly form of chlorine, was investigated to control the disease with low dose of gamma irradiation dose. Interestingly, the gamma irradiated flowers showed more disease severity than the non-irradiated flowers. The combined treatment of gamma irradiation and NaDCC does not affect the severity of the fungal disease, whereas only 70 ppm of NaDCC treatment showed a significantly reduced severity. These results suggest that only chlorination treatment can be applied to control B. cinerea in cut chrysanthemum flowers.

• Macromolecular Research
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• 제12권3호
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• pp.269-275
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• 2004

To graft N-isopropylacrylamide (NIPAAm) onto alginate, varying dosages of ${\gamma}$-rays were irradiated onto alginate films in deionized water and methanol media, which are non-solvents of alginate. We investigated the hydrogels graft ratio, mechanical strength, swelling kinetics and ratio, and behavior with respect to drug release. The graft yield of NIPAAm increased upon increasing the irradiation dose. The use of the aqueous solution increased the graft yield relative to that obtained in methanol. The mechanical strength of the grafted hydrogels increased after grafting with NIPAAm. In a study of the swelling kinetics, we found that all hydrogels reached an equilibrium swollen state within 3 h. The equilibrium swelling ratio of the hydrogels decreased upon increasing the irradiation dose. The swelling ratio of the hydrogels decreased dramatically between 30 and 35$^{\circ}C$ because phase separation of NIPAAm occurred at 32$^{\circ}C$. The swelling process, with respect to the temperature change, was repeatable. An NIPAAm-grafted alginate containing a drug sustained its release rate until 3 h after an initial high drug release caused by a burst effect.

• Journal of Electrical Engineering and Technology
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• 제9권6호
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• pp.2065-2069
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• 2014

The DAC-7512E is a 12-bit digital to analog converter that is low power and a single package with internal buffers. The DAC-7512E takes up minimal PCB area for applications of space power electronics design. The spacecraft mass is a crucial point considering spacecraft launch into space. Therefore, we have performed a TID test for the DAC-7512E 12-bit serial input digital to analog converter to reduce the spacecraft mass by using a low-level Gamma-ray irradiator with $Co^{60}$ gamma-ray sources. The irradiation with $Co^{60}$ gamma-rays was carried out at doses from 0 krad to 100 krad to check the error status of the device in terms of current, voltage and bit error status during conversion. The DAC-7512E 12-bit serial digital to analog converter should work properly from 0 krad to 30 krad without any error.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2016년도 추계학술대회
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• pp.942-943
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• 2016

스테레오 감마선 탐지장치는 감마선을 신호를 측정하여 위치값을 통한 2차원의 감마선 영상을 생성 한후, 가시광영상과 중첩하여 실제 공간상의 감마선 분포를 나타낸다. 스테레오 감마선 탐지장치는 감마선 탐지센서를 포함하는 탐지부와 감마선 신호를 검출하는 신호측정부 그리고 탐지부의 위치를 제어하기 위한 모션제어부로 구성된다. 본 논문에서는 개별적으로 구성된 각각의 모듈을 효율적으로 운용하기 위한 시스템 운용 알고리즘을 개발하였고, 이를 통해 감마선 조사시험장에서 감마선에 대한 영상화 및 분포정보 출력을 확인하였다.

• 미생물학회지
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• 제6권2호
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• pp.54-62
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• 1968

The effect of gamma-ray on yeast cells Sacch. cerevisiae, and the leakage of cellular constituents such as carbohydrates, ribose, amino acids, inorganic phosphates and organic phosphates have been studied. The samples of yeast cells washed throughly and starved intensively, radiation effects were compared with those of control (un-starved), the irradiation dose rates are in the range from 24 Kr. up. to 480, Kr. The loss of 260m$\mu$. absorbing material, are also observed. Mechanisms of membrane damage by gamma-irradiation are discussed corelating to permeability changes and loss of substances, then active and passive transport process are also under considerations in discussion. The experimental results are as follows, 1. Carbohydrates of yeast cell leak out by gamma-irradiation, and amounts of loss increase proportionally as the increasing of radiation dose, curve of carbohydrates loss in starved cells is parallel with those of non-starved cells. 2. Ribose leak out less than that of carbohydrate from irradiated cell, the dose response curve of loss is straight and proportional to the increasing of radiation doses, slope of the curve is much lower than of carbohydrates. 3. Amino acids also leak out and the curve of losses to radiation is not proportional, it is revealed that there are little losses from yeast at lower doses of irradiation. 4. The losses of inorganic phosphates increase unproportionally to the increasing of irradiation doses, there are little leakage at the lower doses of irradiation. The losses of organic phosphates increase proportionally to the increasing of irradiation doses, and the amount of losses are much more than that of inorganic phosphate at lower doses of irradiation. 5. Leakage from irradiated yeast cells was shown to be due to passive transport process not an energy requiring process of ion transport. 6. Loss of 260 m$\mu$. absorbing material is little more than that of control yeast by the gamma-irradiation dose of 120K.r. and 240K.r.

• Journal of Plant Biology
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• 제7권3호
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• pp.9-14
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• 1964

The sensitivities of Chlorella ellipsoidea to ${\gamma}$-ray from Cobalt-60 were determined by measuring the photosynthetic and respiratory activities and the changes in phosphate contents in various fractions of the irradited cells, which were further grown in a standard medium after irradiation, were compared to those of non-irradiated normal cells. The photosynthetic and repiratory activities of the cells were almost inversely proportional to the dose of ${\gamma}$-ray irradiated and the photosynthetic activity was more sensitive than the respiratory activity of the cells. The most sensitive to ${\gamma}$-ray was growth activity, followed by photosynthesis, exogenous and endogenous respirations of the cells in decreasing order. Chlorella cells were so resistant to ${\gamma}$-ray comapred with other organisms that about 280,000 r dose of ${\gamma}$-ray irradiaton was necessary to reduce as much as half the subsequent photosynthetic activity. When the irradiated algae were further cultured in a standard medium, the phosphate contents in the fraction of DNA, RNA and phosphoprotein decreased considerably compared with those of non-irradiated normal cells, while the phosphate contents in the fraction of polyphosphates increased than those of control. Therefore, it was deduced that ${\gamma}$-ray inhibited the synthesis of DNA from polyphosphates, that the growth of Chlorella cells were consequently retarded.

• 대한수의학회지
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• 제34권4호
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• pp.665-678
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• 1994

This study was undertaken to investigate histological changes according to the radiosensitivity in the spermatogenic cells in Korean native pheasants. During spermatogenetic period, testes wete collected from male adult Korean native pheasant and they were used as experimental and control birds. The experimental group was divided into a single-dose whole body irradiation group(400, 600, 800 and 1000 rads) and a split-dose whole body irradiation groups(400/2, 600/2, 800/2 and 1000/2 rads). A Henseky's $^{60}Co$ ${\gamma}$-radiotherapy machine was used for this experiment and the dose rate of $^{60}Co$ ${\gamma}$-ray was 104 rads/min. The experimental birds were sacrificed at 24 and 72 hrs after irradiation and the control pheasants were sacrificed at the same time. General histological changes of seminiferous epithelial cells were observed by hematoxylin-eosin stain with light microscope. The results obtained are summarized as follows ; 1. In the single-dose and the split-dose irradiation groups, the average diameter of the seminiferous tubule was decreased compared with control group. 2. Seminiferous epithelial cells were more severely damaged after 72 hrs than after 24 hrs of single-dose irradiation of 400, 600 and 800 rads but the difference of cell injury was almost not observable with the elapsed time in the group of the single-dose irradiation of 1000 rads. 3. The damage of spermatogenic cells were more severe after 24 hrs than after 72 hrs of the split-dose irradiation of 400 rads but the split-dose irradiation of 600, 800 and 1000 rads were more severe after 72 hrs than after 24 hrs.

• 동아시아식생활학회지
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• 제15권1호
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• pp.106-111
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• 2005

The gamma irradiation effect of dried fernbraken was investigated on the physical and sensory qualities during and after soaking process. Dried fernbraken packaged in vacuum was irradiated up to 7 kGy with v-ray produced by 132 Cs at 0℃. Moisture content and rehydration rate of gamma-irradiated fernbraken after soaking increased significantly depending on the irradiation doses(p<0.05). Lightness(L), redness(a) and yellowness(b) values of Hunter color system increased significantly in the gamma-irradiated fernbraken after soaking, compared with control, while the hardness and chewiness by the texture analyser decreased significantly in irradiated ones. Sensory evaluation results showed that the mean scores of flavor, appearance, taste, texture and over-all acceptability in soaked fernbraken irradiated were not significantly different from those in control, except higher preference score of texture in irradiated ones. From these results, it might be concluded that the irradiation does not affect the physical and sensory qualities of dried fernbraken during and after soaking, especially in texture.