• The Journal of the Korea Contents Association
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• v.11 no.12
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• pp.357-363
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• 2011

The aim of this study is to compare radiation dose in diagnostic X-ray radiography and calculated by different mathematical equation. The result of ESDs direct measurement and that calculated by Mori NDD-M shows the biggest difference. On the other hand, equation by Edmonds shows the lowest difference of ESDs. Also, Rectification due to the difference between direct dose measurement and calculation method commutated three-phase, single phase and inverter type, show less difference in the drive way. In conclusion, this study can be helpful for expecting radiation dose-exposure and control exposure parameters for the diagnostic x-ray radiography.

• Research in Mathematical Education
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• v.14 no.4
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• pp.361-380
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• 2010

Some 400 Secondary One (i.e. seventh-grade) students from 10 schools were provided with non-routine mathematical problems in their normal mathematics classes as exercises for one academic year. Their attitudes toward mathematics, their conceptions of mathematics and their problem-solving performance were measured both in the beginning and at the end of the year. Hierarchical regression analyses revealed that the introduction of an appropriate dose of non-routine problems would generate some effects on the students' conceptions of mathematics. A medium dose of non-routine problems (as reported by the teachers) would result in a change of the students' conception of mathematics to perceiving mathematics as less of "a subject of calculables." On the other hand, a high dose would lead students to perceive mathematics as more useful and more as a discipline involving thinking. However, with a low dose of non-routine problems, students found mathematics more "friendly" (free from fear). It is therefore proposed that the use of non-routine mathematical problems to an appropriate extent can induce changes in students' "lived space" of mathematics learning and broaden their conceptions of mathematics and mathematics learning.

• Journal of radiological science and technology
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• v.42 no.5
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• pp.365-371
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• 2019

We have developed and applied a diagnostic Multi-Leaf Collimator (MLC) to optimized the X-ray field in medical imaging and the usefulness evaluated through the fusion of infrared image and X-ray image acquired by infrared camera. The hand and skull radiography with multi-leaf collimator(MLC) showed significant area dose reductions of 22.9% and 31.3% compared to ARC and leakage dose was compliant with KS A 4732. Also scattering doses of 50 cm and 100 cm showed a significant decrease to confirm the usefulness of MLC. It was confirmed that the fusion of infrared images with an adjustable degree of transparency was possible in the X-ray images. Therefore, fusion of anatomical information with physiological convergence is expected to contribute and improvement of diagnostic ability. In addition, the feasibility of convergence X-ray imaging and DITI devices and the possibility of driving MLC with infrared images were confirmed.

• Nuclear Engineering and Technology
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• v.56 no.1
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• pp.335-339
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• 2024

Employees of nuclear medicine facilities performing medical procedures with the use of open radioactive sources require continuous detailed control of exposure to ionizing radiation. Thermoluminescent (TL) detectors placed in dosimeters: for the whole body, for lenses, ring and wrist dosimeters were used to assess exposure. The highest whole-body exposure of (1.70 ± 1.09) µSv/GBq was recorded in nurses administering radiopharmaceutical to patients. The highest exposure to lenses and fingers was recorded for employees of the quality control zone and it was (8.08 ± 2.84) µSv/GBq and a maximum of (1261.46 ± 338.93) µSv/GBq, respectively. Workers in the production zone received the highest doses on their hands, i.e. (175.67 ± 13.25) µSv/GBq. The measurements performed showed that the analyzed workers may be classified as exposure category A. Wrist dosimeters are not recommended for use in isotope laboratories due to underestimation of ionizing radiation doses. Appropriately selected shields, which significantly reduce the dose received by employees, must be used in isotope laboratories. Periodic measurements confirmed that the appropriate optimization of exposure reduces the radiation doses received by employees.

• Korean Journal of Breeding Science
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• v.40 no.1
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• pp.15-21
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• 2008

It was previously pointed out that mutation is the ultimate source of variation. Adequate variation is needed for plant breeding if there is a limitation in natural genetic resources. When the ionizing radiation has been known to cause chromosomal and genomic alternations, it is widely used for inducing mutagenesis. The electron beam as an ionizing radiation is the principal physical mutagens that induces mutation and effectively used in plant breeding. Since dose-response relationships of electron beam in plant species are rarely known, we investigated the seed germination rate and early seedling growth of irradiated seeds of creeping bentgrass (Agrostis palustris Huds., cv Penn-A1) with various electron beam irradiating conditions (1, 1.3, 2 MeV at both 0.03 mA and 0.06 mA with dose of 100 Gy (Gray) and 0.03, 1, 1.3, 2 MeV at 0.03 mA with dose of 200 Gy, respectively) using electron accelerator at Korea Atomic Energy Research Institute. The growth parameters in terms of shoot length, primary root length, and secondary root length showed similar response between 0.06 / 1 (mA / MeV) at 100 Gy and 0.03 / 0.3 (mA / MeV) at 200 Gy. Bentgrass seed germination was mainly affected by the intensity of irradiated dose (Gray). Germination rate was lowered as the irradiated dose increased. On the other hand, early seedling growth was mainly governed not by the dose of radiation but by voltage.

• Journal of the Korean Applied Science and Technology
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• v.40 no.5
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• pp.955-964
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• 2023

Bee pollen is a valuable apitherapeutic product and has been known to have diverse biological activities, including antimicrobial, anti-inflammatory, and even anticancer activity. However, its effect on the immune system is not well studied and is rather controversial. This study intended to elucidate the biological activity of bee pollen on immunity. For this purpose, we used lyophilized bee pollen after wet grinding, which shows increased extraction of bioactive components and enhanced biological activity. First, lyophilized bee pollen after wet grinding significantly increased the proliferation of splenocytes isolated from normal mice. On the other hand, lyophilized bee pollen after wet grinding dose-dependently reversed splenocyte proliferation by concanavalin A or lipopolysaccharide. To clarify the activity of bee pollen on immunity lyophilized bee pollen after wet grinding was administered daily to mice for five weeks and isolated splenocytes. In this study, there was no significant difference in the population of immune cells and the size of spleen between bee pollen- and sterile water-treated groups. However, proliferation of splenocyte isolated from bee pollen-administered animals was boosted by both concanavalin A and lipopolysaccharide. Finally, kaempferol, a well-known flavonoid from bee pollen, dose-dependently increased splenocyte proliferation by both Con A and LPS. On the other hand, naringenin, another flavonoid in the bee pollen, dose-dependently inhibited the proliferation of splenocytes by Con A and LPS. Together, these data indicate that bee pollen may be able to prime the immunity to boost immune reaction after inflammation.

• The Journal of the Korea Contents Association
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• v.13 no.8
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• pp.301-307
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• 2013

In the present study, space doses generated during X-ray radiography of hand, head, and abdomen, etc. were examined and whether the intensity of space doses of scattering rays is attenuated by the "inverse square law of distance" was figured out. First, the space doses of X-ray with small amounts of generated scattering rays such as hand radiography were mostly attenuated by the "inverse square law of distance" and were not detected at all at a distance of 2m. Second, the space doses of X-ray with large amounts of generated scattering rays such as head or abdomen radiography attenuated in higher rates than the rates under the "inverse square law of distance" at distances ranging from 30cm to 1m from the center of the irradiation field and were attenuated by the "inverse square law of distance" at distances ranging from 1m to 2m. Therefore, in X-ray rooms, the subject should be at least 2m away from the center of the irradiation field in the case of hand radiography and X-ray exposure prevention actions using protective devices are required in the entire spaces of the X-ray rooms in the case of head or abdomen radiography.

• Applied Chemistry for Engineering
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• v.7 no.5
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• pp.946-953
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• 1996

The effect of absorbed dose, dose rate, cationic salts and solvent on the grafting yield was evaluated when acrylic acid was grafted onto polypropylene fabric by simultaneous irradiation process. Low dose rate when irradiated with the same absorbed dose led to a high grafting yield. On the other hand, the grafting yield increased with dose rate in case the total irradiation times is equal, and the initial rate of grafting was found to be proportional to be 0.74 power of dose rate. $FeSO_4{\cdot}7H_2O$ was found to be the most effective additive for high grafting yield, while inhibiting homopolymer formation. It was impossible to induce radiation grafting without the addition of the certain amount of salt, but the grafting yield decreased with increasing metallic salt.

• Journal of Radiation Protection and Research
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• v.41 no.3
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• pp.229-236
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• 2016

Background: In order to manage the patient exposure dose in X-ray diagnosis, it is preferred to evaluate the entrance skin dose; although there are some evaluations about entrance skin dose, a small number of report has been published for direct measurement of patient. We think that a small-type optically stimulated luminescence (OSL) dosimeter, named nanoDot, can achieve a direct measurement. For evaluations, the corrections of angular and energy dependences play an important role. In this study, we aimed to evaluate the angular and the energy dependences of nanoDot. Materials and Methods: We used commercially available X-ray diagnostic equipment. For angular dependence measurement, a relative response of every 15 degrees of nanoDot was measured in 40-140 kV X-ray. And for energy dependence measurement, mono-energetic characteristic X-rays were generated using several materials by irradiating the diagnostic X-rays, and the nanoDot was irradiated by the characteristic X-rays. We evaluated the measured response in an energy range of 8.1-75.5 keV. In addition, we performed Monte-Carlo simulation to compare experimental results. Results and Discussion: The experimental results were in good agreement with those of Monte-Carlo simulation. The angular dependence of nanoDot was almost steady with the response of 0 degrees except for 90 and 270 degrees. Furthermore, we found that difference of the response of nanoDot, where the nanoDot was irradiated from the randomly set directions, was estimated to be at most 5%. On the other hand, the response of nanoDot varies with the energy of incident X-rays; slightly increased to 20 keV and gradually decreased to 80 keV. These results are valuable to perform the precise evaluation of entrance skin dose with nanoDot in X-ray diagnosis. Conclusion: The influence of angular dependence and energy dependence in X-ray diagnosis is not so large, and the nanoDot OSL dosimeter is considered to be suitable dosimeter for direct measurement of entrance surface dose of patient.

• Korean Journal of Agricultural Science
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• v.48 no.4
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• pp.1003-1013
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• 2021

Thioredoxin (TRX) protein is an antioxidant responsible for reducing other proteins by exchanging cysteine thiol-disulfide and is also known for its anti-allergic and anti-aging properties. On the other hand, epidermal growth factor (EGF) is an important material used in the cosmetics industry and an essential protein necessary for dermal wound healing facilitated by the proliferation and migration of keratinocytes. EGF also assists in the formation of granulation tissues and stimulates the motility of fibroblasts. Hence, genetically modified soybeans were developed to overexpress these industrially important proteins for mass production. A single-dose oral-toxicity-based study was conducted to evaluate the potential toxic effects of TRX and EGF proteins, as safety assessments are necessary for the commercial use of seed-specific protein-expressing transgenic soybeans. To achieve this rationale, TRX and EGF proteins were mass purified from recombinant E. coli. The single-dose oral-toxicity tests of the TRX and EGF proteins were carried out in six-week old male and female Institute of Cancer Research (ICR) mice. The initial evaluation of the single-dose TRF and EGF treatments was based on monitoring the toxicity signatures and mortality rates among the mice, and the resultant mortality rates did not show any specific clinical symptoms related to the proteins. Furthermore, no significant differences were observed in the weights between the treatment and control groups of male and female ICR mice. After 14 days of treatment, no differences were observed in the autopsy reports between the various treatment and control groups. These results suggest that the minimum lethal dose of TRX and EGF proteins is higher than the allowed 2,000 mg·kg^-1 limit.