• Radiation Oncology Journal
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• v.12 no.2
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• pp.129-141
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• 1994

Intracellular ions which have a major role in cellular function have been reported to affect repair of radiation damage. Recently it has been reported that ouabain sensitizes A549 tumor cellls but not CCL-120 normal cells to radiation. Ouabain inhibits the $Na^+-K^+$-pump rapidly thus it increases intracellular Na concentration, Vanadate which is distributed extensively in almost all living organisms is known to be a $Na^+-K^+$-ATPase inhibitors, This study was performed to see any change in radiosensitivity of tumor cell by vanadate and any role of $Na^+-K^+$ATPase in radiosensitization. Experiments have been carried out by pretreatment with vanadate in human cell line(A549, JMG) and mouse cell line(L1210, spleen). For the cell survival MTT assay was performed for A549 and JMC cells and frypan blue dye exclusion test for L120, and spleen cells. Measurements of $Na^+-K^+$-ATPase activity in control, vanadate treated cell, radiation treated cell (9 Gy for A549 and JMG, 2 Gy for L1201, spleen), and combined $10^{-6}M$ vanadate and radiation treated cells were done. The results were summerized as fellows. 1. L1210 cell was most radiosensitive, and spleen cell and JMG cell were intermediate, and A549 cell was least radiosensitive. 2. Mininum or no cytotoxicity was seen with vanadate below concentration of $10^{-6}M$. 3. In A549 cells there was a little change in radiosensitivity with treatment of vanadate. However radiation sensitization was shown in low dose level of radiation i. e. 2- Gy. In JMG cells no change in radiosensitivity was noted. Both L1210 and spleen cell had radiosensitization but change was greater in tumor cell. 4. $Na^+-K^+$-ATPase activity was inhibited significantly in tumor cell by treatment of vanadate. 5. Radiaiton itself inhibited $Na^+-K^+$-ATPase activity of tumor cell with high $Na^+-K^+$-ATPase concention. Increase in radiosensitivity by vanadate was closely associated with orginal $Na^+-K^+$-ATPase contents. From the above results vanadate had little cytotoxicity and it sensitized tumor cells to radiation. Inhibitory effect of vanadate on $Na^+-K^+$-ATPase activity might be one of the contributing factors for radiosensitization to tumor cells which has greater enzyme activity than that of normal cell. It was suggested vanadate could be used as a potential radiosensitizer for tumor cells.

• Radiation Oncology Journal
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• v.23 no.1
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• pp.43-50
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• 2005

Purpose : A number of genes and their products are Induced early or late following exposure of cells to ionizing radiation. These radiation-Induced genes have various effects on irradiated cells and tissues. Suppression subtractive hybridization (SSH) based on PCR was used to Identify the differentially expressed genes by radiation in cervix carcinoma cells. Materials and Methods : Total RNA and poly $(A)^+$ mRNA were Isolated from Irradiated and non-irradiated HeLa cells. Forward- and reverse-subtracted cDNA libraries were constructed using SSH. Eighty-eight clones of each were used to randomly select differentially expressed genes using reverse Northern blotting (dot blot analysis). Northern blotting was used to verify the screened genes. Results : Of the 17t clones, 10 genes in the forward-subtracted library and 9 genes In the reverse-subtracted library were identified as differentially expressed radiation-induced genes by PCR-select differential screening. Three clones from the forward-subtracted library were confirmed by Northern blotting, and showed increased expression in a dose-dependent manner, including a telomerase catalytic subunit and sodium channel-like protein gene, and an ESTs (expressed sequence tags) gene. Conclusion : We Identified differentially expressed radiation-induced genes with low-abundance genes with SSH, but further characterization of theses genes are necessary to clarify the biological functions of them.

• Korean Journal of Food Science and Technology
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• v.4 no.2
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• pp.100-105
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• 1972

This experiment was conducted to investigate the combined effects of radiation and antiseptics on the keeping qualities of pork sausage, which was treated with potassium sorbate and AF-2(2-(-2-furyl)-3-(5-nitro-2-furyl)-acrylamide), and then followed by gamma radiation of 0.25, 0.5, and 0.75 Mrad. Amounts of treated antiseptics were a quarter, half, and full levels of their maximum permissible concentration. Irradiated and unirradiated sausages were stored for 50 days at $5^{\circ}C\;and\;25^{\circ}C$, and their changes in rancidity, volatile basic nitrogen, bacterial counts, pH, and sensory analysis were examined during the storage period. The results obtained are as follows: 1) Preservative effects of antiseptics were manifested at cold storage; antiseptics treatment of a quarter-level and unirradiation following low-temperature storage showed the same good keeping qualities as the combined treatment of full-level antiseptics and radiation of 0.25 Mrad following high-temperature storage. 2) There did not appear to recognize irradiation-odor, while color and odor were deteriorated intensively by storage temperature. Sausage irradiated with 0.75 Mrad has shown slightly noticeable off-odor at the end of storage at $25^{\circ}C$. 3) The most suitable radiation dose was considered to be 0.5 Mrad, which could extend the storage life about $2{\sim}3$ times longer than untreated.

• Nuclear Engineering and Technology
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• v.22 no.1
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• pp.36-44
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• 1990

A safety assessment computer code CALM (Computer program of Assessment for LILW Management) is developed for the theoretical prediction of long-term safety of low-and intermediate-level radioactive waste disposal. CALM is composed of three submodels, which are the resaturation model, the geosphere migration model, and the radiation dose model. For the verification of its usefulness, the safety assessment of an assumed waste repository is performed. The results show that the computer code, CALM developed through this study can be a useful tool for the safety assessment of low- and intermediate-level radioactive waste repository.

• Journal of the Korean Society of Food Science and Nutrition
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• v.37 no.11
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• pp.1529-1533
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• 2008

The detection characteristics of gamma-irradiated ($0{\sim}10.0\;kGy$) medicinal herbs (Platycodon grandiflorum, Acanthopanax chiisanensis) were investigated by photostimulated luminescence (PSL), thermoluminescence (TL), and electron spin resonance (ESR). The results of the PSL, a first screening method in comparison with the TL, showed photon counts greater than 5,000 counts/60 s (positive) in the irradiated samples, while the non-irradiated samples yielded photon counts less than 700 counts/60 s (negative). The TL was also applied for the detection method of irradiated medicinal herbs and showed that the non-irradiated sample revealed a glow curve with a low intensity, while the irradiated samples showed a higher intensity. These results were normalized by re-irradiating the mineral grains with a irradiation dose of 1.0 kGy, and a second glow curve was recorded. The ratio of the intensity of the first glow curve ($TL_1$) to that after the normalization dose ($TL_2$) was determined and compared with the recommended threshold values. TL ratio ($TL_1/TL_2$) was below 0.007 for the non-irradiated sample and higher than 0.1 for all irradiated samples (above 1.0 kGy). ESR spectroscopy revealed specific signals (6.065 mT) derived from free radicals in cellulose containing irradiated medicinal herbs. The P. grandiflorum showed clearer signals than A. chiisanensis. From the results of our studies, the PSL, TL, and ESR determinations were found to be suitable for the detection of irradiated medicinal herbs such as P. grandiflorum and A. chiisanensis.

• Radiation Oncology Journal
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• v.19 no.1
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• pp.1-9
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• 2001

Purpose : To establish the role of stereotactic radiosurgery (SRS) for the treatment of patients with angiographically occult vascular malformation (AOVM). Materials and Methods : Eleven patients (12 lesions) with AOVM were treated with linear accelerator-based SRS between February 1995 and December 1999. A magnetic resonance imaging of each patients showed well-circumscribed vascular lesion with reticulated core of heterogeneous signal intensity and peripheral rim of low signal intensity. SRS were peformed with the median peripheral dose of 16 Gy (range 13~25). A single isocenter was used with median collimator size of 14 mm (range 8~20) diameter. Results : With a median follow-up period of 42 months (range 12~56), rebleeding occurred in 3 AOVMS at 5, 6 and 12 months after SRS but no further bleeding did. Two patients experienced radiation-induced necrosis associated with permanent neurologic deficit and one patient showed transient edema of increased 72 signal intensity. Conclusion : SRS may be effective for the prevention of rebleeding in AOVM located in surgically inaccessible region of the brain. Careful consideration should be needed in the decision of case selection and dose prescription because the incidence of radiation-induced complications is too high to be accepted.

• Progress in Medical Physics
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• v.19 no.3
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• pp.164-171
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• 2008

One of the most important task in commissioning intensity modulated radiotherapy (IMRT) into a clinic is the characterization of dosimetry performance under small monitor unit delivery conditions. In this study, method of evaluating dose monitor linearity, beam flatness and symmetry, and MLC positioning accuracy using a diode array is investigated. Siemens Primus linear accelerator (LA) with 6 and 10 MV x-rays was used to deliver radiation and the characteristics were measured using a multi array diodes. Monitor unit stabilities were measured for both x-ray energies. The dose linearity errors for the 6 MV x-ray were 2.1, 3.4, 6.9, 8.6, and 15.4 % when 20 MU, 10 MU, 5 MU, 4 MU, and 2 MU was delivered, respectively. Greater errors were observed for 10 MV x-rays with a maximum of 22% when 2 MU was delivered. These errors were corrected by adjusting D1_C0 values and reduced to less than 2% in all cases. The beam flatness and symmetry were appropriate without any correction. The picket fence test performed using diode array and film measurement showed similar results. The use of diode array is a convenient method in characterizing beam stability, symmetry and flatness, and positioning accuracy of MLC for IMRT commissioning. In addition, adjustment of D1-C0 value must be performed when a Siemens LA is used for IMRT because factory value usually gives unacceptable beam stability error when the MU/segment is smaller than 20.

• Korean journal of food and cookery science
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• v.24 no.1
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• pp.106-113
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• 2008

This study investigated the effects of gamma irradiation on microbial, physical, and sensory qualities as well as the antioxidant activity of cooked spinach. At 3 kGy of gamma irradiation, microbial growth was inhibited until 4 weeks and 5 days at storage temperatures of 4 and $25^{\circ}C$, respectively. The dose of 2 kGy did not significantly affect hardness; however, Hunter color system values for lightness, redness, and yellowness were changed. Low dose gamma-irradiation (up to 2 kGy) did not significantly affect the antioxidant activity of the cooked spinach. Also, based on a triangle sensory test, the gamma-irradiated cooked spinach was not significantly different from the control. These results, suggest that applying gamma irradiation to cooked vegetables at doses lower than 2 kGy can be recommended to extend shelf-life and maintain quality.

• Korean Journal of Food Science and Technology
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• v.15 no.3
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• pp.231-237
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• 1983

In order to develop the commercial storage method of chestnut by irradiation combined with natural low temperature, a chestnut variety Ok-gwang was stored in a natural low temperature storage room ($450{\times}650{\times}250$ cmH; year-round temperature change, $2-17^{\circ}C$; R.H., 80-85%) on batch scale followed by irradiation with optimum dose level. Sprouting rate of chestnut was 100% after seven month storage in control whereas that of 20-25 Krad irradiated group was only 5-15%. In comparison of rotting rate, weight loss and texture, 25 Krad irradiated group was better than that of control. Moisture and reducing sugar were increased in contrast with the decrease of total sugar during nine month storage and these changes were more remarkable in control. Ascorbic acid content was slightly decreased both in control and irradiated group; more decrement was noticed in control.

• Journal of dental hygiene science
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• v.5 no.3
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• pp.105-112
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• 2005

In spite of relatively low level of radiation dose used at dental clinics, long term exposure may be harmful, so radiation workers at dental clinics must be well aware of its danger. This study was to analyze the factors to have an influence on safety management behavior in the radiography chamber by understanding the relationship among the knowledge, attitudes and behavior in regard with radiation safety management by dental hygienists in order to take preventive measures for dental hygienists and suggest ideas to develop radiation safety training programs. For this, we contacted dental hygienists working at the local dental clinics for 4 months from December of 2003 to march of 2004 and obtained the following findings. 1. Concering the knowledge level of radiation safety management, $8.59{\pm}2.36$ was average score with the highest of 13 and the lowest of 3 from 15-scale test. In addition, knowledge level of radiation safety management by general characteristics showed statistically significant difference according to working experience (p < 0.001), marital status (p < 0.001), attendance rate of radiation safety management training program (p < 0.001), and type of clinic (p < 0.001). 2. Concering the attitude level of radiation safety management, $4.08{\pm}0.50$ is average score with the highest of $4.31{\pm}0.73$ and the lowest of $3.82{\pm}0.89$ by item from 5-scale test. Besides, attitude level of radiation safety management by general characteristics showed statistically significant difference according to age (p < 0.001), working experience (p < 0.05), attendance rate of radiation safety management training program (p < 0.01), and type of clinic (p < 0.001). 3. Concering the behavior level of radiation safety management, $2.89{\pm}0.77$ is average score from 5-scale test, which was relatively low in comparison with the level of attitude and the highest score was $3.82{\pm}0.94$ and the lowest $2.37{\pm}1.04$ by item. Behavior level of radiation safety management by general characteristics showed statistically significant difference according to working experience (p < 0.001) and type of clinic (p < 0.001). 4. From the survey of relationship among knowledge, attitude and behavior of radiation safety management was, we found that the higher the knowledge level of radiation safety management, the higher the level of attitude and behavior, and the higher the attitude level was, the higher the level of behavior.