• Radiation Oncology Journal
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• v.4 no.1
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• pp.1-13
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• 1986

In order to clarify the effect of radiation on the mouse jejunal crypt cells by combined administration of administration and radiation and also to evaluate the enhancing effect of adriamycin, the authors performed this study by delivering single irradiation of 1,000 to 1,600 rad to the whole abdomen of mice by cobalt-60 teletherapy unit. In combination with adriyamycin treatment groups, the drug was administered as single dose of 10 mg/kg either 2 hours before or 4 hours after graded single dose,900 to 1,400 rad, of irradiation. The authors studied the quantitative changes of intestinal crypt cells by microcolony survival assay technique and the morphological changes of small intestinal villi by scanning electron microscope in mice following to combined therapy with adriamycin and irradiation, The average number of jejunal crypts per circumference was $130{\pm}16$ in control group. The mean lethal dose(Do) of each irradiation alone and combined therapy groups 2 hours before and 4 hours after irradiation, were 160, 170, and 170 rad in cell survival curves, respectively. The dose effect factor(DEF) of adriamycin in each groups of pre-irradiation and post-irradiation were 1.19 and 1.26, respectively. The conical shaped villi were noted on 1,200 rad in irradiation alone group and 1,000 rad in combined groups. For the proper clinical application we must be careful of the radiation injury to small bowel when the anticancer chemotherapy and radiation therapy to the abdomen and pelvic area are used as combined therapeutic modality.

• Nutrition Research and Practice
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• v.1 no.4
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• pp.279-284
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• 2007

Solar ultraviolet (UV) irradiation leads to distinct changes in the skin connective tissues by degradation of collagen, which is a major structural component in the extracellular matrix. UV irradiation induces the production of matrix metalloproteinases (MMP) capable of attacking native fibrillar collagen and responsible for inhibiting the construction of collagenous extracellular matrix. In this study, we attempted to investigate the protective actions of Rubus coreanus ethanol extract (RCE) on the MMP production and the consequent procollagen/collagen degradation in UV-B-irradiated human dermal fibroblasts. The analytical data showed that Rubus coreanus ethanol extract was mostly comprised of cyanidin 3-rutinoside. Pre-treatment of fibroblasts with this extract inhibited UV-B-induced production of MMP-1, MMP-8 and MMP-13 in dose-dependent manners. In addition, Western blot analysis and immunocytochemical staining assay revealed that RCE markedly augmented the cellular levels of procollagen/collagen declined in UV-B-exposed dermal fibroblasts. These results demonstrate that RCE blocks UV-B-induced increase of the collagen degradation by inhibiting MMP production. Thus, RCE may act as an agent inhibiting excessive dermal collagen degradation leading to the skin photoaging.

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.625-626
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• 2008

The magnetic domain-refining techniques such as ball scratching, laser irradiation and plasma have been developed to reduce the domain wall spacing and thus iron losses in Fe-3%Si grain-oriented silicon steels. In view point of magnetic properties, it was supposed that the locally residual stresses change the magnetoelastic energy of the material and thus the spacing between $180^{\circ}$ domain walls decreases in order to reduce the magnetostatic energy. The effect of laser irradiation on iron loss and magnetostriction reduction for Fe-3%Si grain-oriented steel were investigated. Since the local tensile stresses were induced at the surface of Fe-3%Si steel by the laser irradiation, the minimum iron loss caused by reducing eddy current loss was obtained in spiete of the decrease of permeability by hindering eddy current loss was obtained in spite of the decrease of permeability by hindering the domain wall movement around the induced stress field. Furthermore, the laser treated 3%Si steel has lower magnetostriction as compared to non laser-treated steel and is less sensitive to applying pre-stresses due to the volume reduction of $90^{\circ}$ domain in materials.

• Journal of the Optical Society of Korea
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• v.13 no.1
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• pp.80-85
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• 2009

An experimental study of energy absorption and x-ray emission from ultrashort laser pulse irradiation of in-situ produced solid clusters has been performed. Silver clusters produced by a 30 mJ, 300 ps laser pulse were irradiated up to an intensity of $3{\times}10^{17}\;W/cm^2$ by a 70 mJ, 45 fs compressed laser pulse from the same Ti:sapphire laser. Absorption of the laser light exceeding 70% was observed, resulting in an x-ray yield (>1 keV) of ${\sim}60{\mu}J$ pulse. This may constitute a much simpler means of intense x-ray generation using ultrashort laser pulses as compared to the irradiation of structured / pre-deposited cluster targets, and it offers higher x-ray conversion efficiency than that from gas clusters and planar solid targets.

• Korean Journal of Microbiology
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• v.5 no.1
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• pp.1-6
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• 1967

The environmental effects on radio-sensitivities of Lactobacillus and Saccharomyces cerevisiae were studied; Liquid suspensions of Lactobacillus and yeast were gamma-irradiated under various conditions; temperatures, hydrogen ion concentrations, amino acids and vitamins were treated seperately with variations of concentrations. (shown in figures) It is found that simultaneous heat treatment is effective to sterilize microorganisms than pre after treatment, and concentration of hydrogen ion does not affect the lethalty of yeast but or Lactobacilli was affect at the range of pH. 5.0 to 7.0. Ascorbic acid, thiamin and pyridoxine were protective dependently against lethal action of gamma-ray and its protective effects increase with the increasings of concentrations. Glutamic acid, aspartic acid, tyrosine and phenylalanine were proved to be protective for both strains at 0.1 between 1.0 percent. It can be suggested that industrial sterilizing doses of irradiation by gamma-ray for food should be applied more than those dose of saline or buffer suspension, because natural food stuffs are rich of vitamins and amino acids.

• Proceedings of the Korean Society of Veterinary Pathology Conference
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• 2000.09a
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• pp.20-20
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• 2000

The objective of this investigation was to evaluate of influence of gestational age at exposure on the prenatal effects of gamma-radiation. Pregnant ICR mice were exposed to single dose of 2.0 Gy gamma-radiation at gestation days from 2.5 to 15.5 days post-coitus. The animals were sacrificed on day 18 of gestation and the fetuses were examined for mortality, growth retardation, change in head size and any other morphological abnormalities. The only demonstrable effect of irradiation during the pre-implantation period was an increase in prenatal mortality. (omitted)

• Textile Coloration and Finishing
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• v.12 no.4
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• pp.239-247
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• 2000

The coloring matter was extracted from the heartwood of Amur cork tree by distilled water. Change of UV-Visible spectra of coloring matter solution by extraction condition and stability for irradiation were determined, and the effect of repeated dyeing with condition of dyebath and mordanting method on shade depth and lightfastness were also investigated. The results are as follows : 1) Absorbance of Amur cork tree extract increased with the lapse of extraction time. λmax of color solution extracted from Amur cork tree was found at 420, 333, and 262nm. 2) Absorbance of Amur cork tree extract decreased remarkably after 2hr irradiation. 3) The K/S of silk fabrics increased with the increase of dyeing temperature, time, amounts of Amur cork tree for extraction, and pH of color solution. 4) K/S of silk fabrics dyed by repeated dyeing method was affected by pH and concentration of color solution. 5) Lightfastness of silk twice dyed with Amur cork tree extract after pre-mordanted by 8%(o.w.f) chromium acetate was moderately improved.

• Journal of the Korean Chemical Society
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• v.6 no.1
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• pp.64-68
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• 1962

The graft polymerization of styrene to polyvinyl alcohol using a photosensitizer(benzophenone) and ultraviolet light was studied. Styrene was grafted onto polyvinyl alcohol up to when polyvinyl alcohol was pre-immersed in water and irradiated by ultraviolet light for 24 hours styrene solution of benzophenone(0.01 molarity). The highest percentage of graft obtained in the grafting which was proceeded in the presence of water added immediately before irradiation was 29%. The grafting was proportional to irradiation time within a certain limit of time, i.e., 24 hours, and presumably was initiated at the surface. After a certain degree of grafting a definite maximum was reached. Graft polymer prepared in this experiment showed high resistance to various solvents.

• ETRI Journal
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• v.27 no.4
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• pp.449-452
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• 2005

The electrical characteristics of solid state devices such as the bipolar junction transistor (BJT), metal-oxide semiconductor field-effect transistor (MOSFET), and other active devices are altered by impinging photon radiation and temperature in the space environment. In this paper, the threshold voltage, the breakdown voltage, and the on-resistance for two kinds of MOSFETs (200 V and 100 V of $V_{DSS}$) are tested for ${\gamma}-irradiation$ and compared with the electrical specifications under the pre- and post-irradiation low dose rates of 4.97 and 9.55 rad/s as well as at a maximum total dose of 30 krad. In our experiment, the ${\gamma}-radiation$ facility using a low dose, available at Korea Atomic Energy Research Institute (KAERI), has been applied on two commercially available International Rectifier (IR) products, IRFP250 and IRF540.

• Korean Journal of Food Science and Technology
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• v.10 no.1
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• pp.88-91
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• 1978

When the food poisoning bacteria Salmonella enteritidis and S. typhimurium were treated with radiation (cobalt-60 r-rays) and heat (10 minutes at $45^{\circ}C\;or\;50^{\circ}C$), their sterilizing effect was revealed differently depending on the order of treatments. Post-irradiation heating showed a synergistic effect whereas pre-irradiation heating revealed the opposite effect and the effects differed slightly with heating temperature.