• Korean Journal of Food Science and Technology
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• v.5 no.2
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• pp.101-107
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• 1973

1) For the purpose of preparation of food and fodder yeasts from nonedible seaweed, two suitable Candida yeasts have been isolated from seaweed compost. 2) They had the ability of fermenting galactose, sucrose and glucose, and could not ferment maltose and mannit, but could assimilate mannit. 3) NaCl concentration from 1 to 2% had no remarkable effect on growth of yeast and the optimum pH was $4{\sim}5$. 4) In the acid hydrolyzate of brown seaweed (Ecklonia cava Kjellman, Sargassum fulvellum AGARDH) an amorphous deposit was produced during storage after neutralization of media and its removal always delayed yeast growth, but addition of $(NH_4)_2SO_4$ and $NaH_2PO_4$ to media could increase the assimilation of reducing sugar and yeast yield. 5) $Co^{60}$ gamma ray irradiation (dose rate : 1 Mrad/hr, BNL shipboard irradiator) of seaweed had not so much effect on the hydrolysis of carbohydrates and nitrogen compounds in seaweed but could increase the yeast production from seaweed hydrolyzate. 6) The yeast yield was $7{\sim}8$ g of dry yeast per 100 g of seaweed by cultivation with jar fermentor.

• Journal of Korean Neurosurgical Society
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• v.50 no.2
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• pp.99-102
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• 2011

Objective : The purpose of this retrospective study was to evaluate the outcome of gamma knife radiosurgery (GKRS) and/or whole brain radiation therapy (WBRT) for the treatment of small cell lung carcinoma (SCLC) metastasis to the brain. Methods : From 2000 to 2010, 50 patients underwent GKRS for metastatic brain lesions originating from SCLC. Among these patients, 11 received prophylactic cranial irradiation (PCI) before the development of metastatic lesions (PCI group), and GKRS was performed as an initial treatment for newly diagnosed lesions in 12 patients who had not received PCI (primary GKRS group). In addition, GKRS was performed as a salvage treatment for progressive lesions after WBRT in 27 patients (salvage GKRS group). The medical records and imaging data of all patients were retrospectively analyzed. Results : The overall survival of the 50 patients was 20.8 months (range 1-53) after the diagnosis of primary tumor and 12.0 months (range 1-47) after the development of cerebral metastasis. Median survival after GKRS was 4.8 months (range 1-15) in the PCI group, 4.6 months (range 0-18) in the primary GKRS group, and 7.6 months (range 0-33) in the salvage GKRS group. Further treatment for progressive lesions after GKRS was necessary in 15 patients, after a mean interval of 3.8 months. Causes of death were systemic organ failure in 15 patients, deterioration of neurological state in 13 patients, and unknown or combined causes in 16 patients. The local control rate of the lesions treated with GKRS was 76.4% (decreased in 13 patients and stable in 16 patients at the final imaging follow-up (mean 5.60 months). Conclusion : GKRS is an effective local treatment for brain metastasis from SCLC both as an initial treatment for newly diagnosed lesions after PCI and as a salvage treatment for recurrent or progressive lesions. However, the survival benefit is not significant because most patients die of systemic multi-organ failure with a short life expectancy.

• Food Science and Preservation
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• v.16 no.2
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• pp.211-216
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• 2009

This study determined the photostimulated luminescence(PSL), thermoluminescence(TL), and electron spin resonance(ESR) properties of wheat and corn irradiated with 0-10 kGy of gamma-ray or electron-beam. PSL values of both irradiated grains, regardless of radiation source, were 241-429 photons/sec in nonirradiated samples(negative values, defined as ${\leq}700$ photons/60 sec) and 5,528-40,870 photons/60 sec in irradiated ones(positive values, defined as ${\geq}5,000$ photons/sec), thereby distinguishing irradiated from nonirradiated samples. The TL glow curves($TL_1$) peaked at around $300^{\circ}C$ in nonirradiated samples, but at about $180^{\circ}C$ in irradiated samples, at high intensities, regardless of radiation source. The TL ratios($TL_1/TL_2$) calculated to strengthen $TL_1$ data reliability were less than 0.03 for nonirradiated samples and over 0.20 for irradiated materials, in good agreement with threshold values for nonirradiated(${\leq}0.1$) and irradiated(${\geq}0.1$) samples. ESR analysis was not applicable in identification of irradiated wheat and corn. Electron-beam irradiation resulted in higher PSL and TL signals than did gamma-rays, at the same applied doses.

• Progress in Medical Physics
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• v.14 no.4
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• pp.225-233
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• 2003

The goal of a radiation treatment plan is to deliver a homogeneous dose to a target with minimal irradiation of the adjacent normal tissues. Dose uniformity is especially important for stereotactic radiosurgery using a linear accelerator. The dose uniformity and high dose delivery of a single spherical dose distribution exceed 70％. This also results with a similar stereotactic radiosurgical plan using a Gamma Knife. The dose distribution produced in a stereotactic radiosurgical plan using a Gamma Knife and Linear accelerator is spherical, and the application of the sphere packing arrangement in a real radiosurgical plan requires much time and skill. In this study, we found a characteristic of dose distribution with transformation of beam parameters that must be considered in a radiosurgical plan for effective radiosurgery. First, we assumed a cylinder type tumor model and a cube type tumor model. Secondly, the results of the tumor models were compared and analyzed with dose profiles and DVH_(Dose Volume Histogram) representative dose distribution. We found the optimal composition of beam parameters_(i.e. collimator size, number of isocenter, gap of isocenters etc.), which allowed the tumor models to be involved in the isodose curve at a high level. In conclusion, the characteristics found in this study are helpful for improving the effectiveness and speed of a radiosurgical plan for stereotactic radiosurgery.

• Applied Chemistry for Engineering
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• v.8 no.3
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• pp.489-501
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• 1997

Electropolymerization of 2-vinylnaphthalene (2-VN) and methylmethacrylate (MMA) with high radiation resistance property was conducted on the surfaces of carbon fibers by using a nonaqueous solution of comonomers dissolved in N,N-dimethylformamide containing sodium nitrate as a supporting electrolyte. The fabrication of carbon fiber/2-VN/MMA prepreg was performed electrochemically in 1:1 comonomer solution. Electropolymerization was conduced by changing the current density, initial comonomer concentration, and reaction time. The weight gain on the surface of the carbon fibers was measured by thermogravimetric analyser (TGA). The highest weight gain of 50 wt% was obtained at 600mA/g~800mA/g current density range, but the weight gain was rapidly decreased above 800mA/g current density. The weight gain was increased with the concentration of comonomer, while the concentration of electrolyte had almost no effect on the weight gain. At 300mA/g current density, weight gain rate was increased abruptly to the initial 30 minutes of reaction time. After that the rate was decreased due to the generation of gas bubbles. In order to check the effect of coated polymers on the radiation resistance, morphology changes before and after $\gamma$-ray irradiation was investigated for the composites.

• Korean Journal of Food Science and Technology
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• v.49 no.3
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• pp.252-257
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• 2017

In this study, the physicochemical properties of irradiated (gamma-ray and electron-beam) soybeans with different processing (dry and powder) and origins (Korea, China, and USA) were investigated and compared. The results of photostimulated luminescence (PSL) screening indicated that all non-irradiated soybeans showed photon counts (PCs) ${\leq}700$, while all irradiated soybeans showed positive values-gamma-ray 5,815-39,591 count/min; electron beam 5,791-60,055 count/min. The results of thermoluminescence (TL) analysis of all irradiated soybeans indicated that the $TL_1$ glow curves exhibited maximum peaks at 150-250. TL ratio of irradiated samples was ${\geq}0.1$; therefore, the clear identification of irradiated samples was guaranteed by analysis of the $TL_1$ curve shape and TL ratios. The results of electron spin resonance (ESR) signal of 3 irradiated and dried soybeans showed two side peaks mutually spaced at 6.0 mT (cellulose radical). Non-specific signal was detected for all irradiated soybean powders; hence, ESR analysis could not be performed.

• Journal of the Korean Society of Food Science and Nutrition
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• v.42 no.6
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• pp.898-903
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• 2013

This study was investigated the potential toxicity of gamma-irradiated chocolate ice cream for its future use in space. Chocolate ice cream was irradiated at a dose of 30 kGy at a temperature of $-20^{\circ}C$. For the animal study, AIN-93G was used as a control diet and irradiated and non-irradiated chocolate ice cream diets were administered to male and female ICR mice (ten mice per group) for three months. During the experimental period, the group fed irradiated chocolate ice cream did not show any changes in appearance, behavior, mortality, body weight, organ weight, or food consumption compared to the control. Also, all biochemical parameters, including hematology profiles, erythrocyte counts, and serum biochemical values were in normal ranges. In histopathological examinations of liver and kidney tissues, there were no significant differences between the control group and the group fed irradiated chocolate ice cream. These results indicate that chocolate ice cream irradiated at 30 kGy did not cause any toxic effects and could be applied for the development of safe and hygienic space food.

• The Korean Journal of Nuclear Medicine
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• v.33 no.2
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• pp.172-177
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• 1999

Purpose: The purpose of this study was to ascertain whether radiation adaptive response could be induced by Tc-99m-methylene diphosphonate (Tc-99m-MDP) in peripheral lymphocytes of patients undergoing bone scintigraphy. Materials and Methods: Lymphocytes from 22 patients (6 males, 16 females, mean age $50{\pm}14$ years) were collected before and after bone scintigraphy using 740 MBq Tc-99m-MDP Lymphocytes from 10 controls (6 males, 4 females, mean age $43{\pm}7$ years) were also collected. They were exposed to challenge dose of 2 Gy gamma rays using a cell irradiator. Number of ring-form and dicentric chromosomes per 600 cells (chromosomal aberrations) was counted under the light microscope. Results: Chromosomal aberrations in patients before bone scintigraphy ($385.1{\pm}30.5$) was not different from that of controls ($367.8{\pm}36.6$). However, chromosomal aberrations in patients after bone scintigraphy was significantly decreased to $192.6{\pm}22.1$ (p=0.0001). Conclusion: Low dose gamma-irradiation by Tc-99m-MDP used for bone scintigraphy induces a cytogenetic adaptive response in peripheral lymphocytes.

• Progress in Medical Physics
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• v.13 no.2
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• pp.98-103
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• 2002

The purpose of this study was to evaluate the absorbed dose to the coronary artery segment from various sized balloon angio catheters. The liquid form of Ho-166 was produced at the KAERI by (n, ${\gamma}$ ) reaction. We used GafChromic film for the estimation of the absorbed dose by beta particles. The exposed films were read using a videodensitometer. Several film exposures were made with varying irradiation times and activities. A modified micrometer was used for the measurement of the absorbed dose distribution near the balloon surface. Four balloons of coronary catheters evaluated were 30 m long and 2.5, 3.0, 3.5 and 4.0 mm in diameter. All doses are plotted in units of Gy/min/GBq/ml as a function of radial distance in mm from the surface of balloon. The absorbed dose rate was 0.86, 1.01, 1.11 and 1.24 Gy/min/GBq/ml at a balloon surface for various balloon diameter 2.5, 3.0, 3.5 and 4.0 mm respectively. Using a vacuum pump, the air in the balloon was evacuated prior to instillation of the Ho-166 source. By removing air bubbles in the balloon, the absorbed dose distribution was more uniform.

• Toxicological Research
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• v.20 no.2
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• pp.89-100
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• 2004

The comet assay (also called the single-cell gel electrophoresis assay) has been widely used for detecting DNA damage and repair in individual cells. Since the conventional methods of evaluating comet assay data using frequency statistics are unsatisfactory we developed a new quantitative measure of DNA damage/repair that is based on all information residing in the dose/time-response curves of a comet experiment. Blood samples were taken from 25 breast cancer patients before undergoing radiotherapy. The comet assay was performed under alkaline conditions using isolated lymphocytes. Tail DNA, tail length, tail moment and tail inertia of the comet were measured for each patient at four doses of $\gamma$-rays (0, 2, 4 and 8 Gy) and at four time points after irradiation (0, 10, 20 and 30 min) using 100 cells each. The resulting three-dimensional dose-time response surface was modeled by multiple regression, and the second derivative, termed 2D, on dose and time was determined. A software module was programmed in SAS/AF to compute 2D values. We applied the new method successfully to data obtained from cancer patients to be assessed for their radiation sensitivity. We computed the 2D values for the four damage measures, i.e., tail moment, tail length, tail DNA and tail inertia, and examined the pairwise correlation coefficients of 2D both on the log scale and the unlogged scale. 2D values based on tail moment and tail DNA showed a high correlation and, therefore, these two damage measures can be used interchangeably as far as DNA repair is concerned. 2D values based on tail inertia have a correlation profile different from the other 2D values which may reflect different facets of DNA damage/repair. Using the dose-time response surface, other statistical models, e.g., the proportional hazards model, become applicable for data analysis. The 2D approach can be applied to all DNA repair measures, Le., tail moment, tail length, tail DNA and tail inertia, and appears to be superior to conventional evaluation methods as it integrates all data of the dose/time-response curves of a comet assay.