• Journal of the Korean Society of Radiology
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• v.17 no.4
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• pp.489-495
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• 2023

Radiation shielding facilities are constructed in locations where diagnostic radiation generators are installed, with the aim of preventing exposure for patients and radiation workers. The purpose of this study is seek to compare and validate the trend of attenuation thickness of lead, the primary material in these radiation shielding facilities, at different maximum tube voltages by Monte Carlo simulations and measurement. We employed the Monte Carlo N-Particle 6 simulation code. Within this simulation, we set a lead shielding arrangement, where the distance between the source and the lead sheet was set at 100 cm and the field of view was set at 10 × 10 cm². Additionally, we varied the tube voltages to encompass 80, 100, 120, and 140 kVp. We calculated energy spectra for each respective tube voltage and applied them in the simulations. Lead thicknesses corresponding to attenuation rates of 50, 70, 90, and 95% were determined for tube voltages of 80, 100, 120, and 140 kVp. For 80 kVp, the calculated thicknesses for these attenuation rates were 0.03, 0.08, 0.21, and 0.33 mm, respectively. For 100 kVp, the values were 0.05, 0.12, 0.30, and 0.50 mm. Similarly, for 120 kVp, they were 0.06, 0.14, 0.38, and 0.56 mm. Lastly, at 140 kVp, the corresponding thicknesses were 0.08, 0.16, 0.42, and 0.61 mm. Measurements were conducted to validate the calculated lead thicknesses. The radiation generator employed was the GE Healthcare Discovery XR 656, and the dosimeter used was the IBA MagicMax. The experimental results showed that at 80 kVp, the attenuation rates for different thicknesses were 43.56, 70.33, 89.85, and 93.05%, respectively. Similarly, at 100 kVp, the rates were 52.49, 72.26, 86.31, and 92.17%. For 120 kVp, the attenuation rates were 48.26, 71.18, 87.30, and 91.56%. Lastly, at 140 kVp, they were measured 50.45, 68.75, 89.95, and 91.65%. Upon comparing the simulation and experimental results, it was confirmed that the differences between the two values were within an average of approximately 3%. These research findings serve to validate the reliability of Monte Carlo simulations and could be employed as fundamental data for future radiation shielding facility construction.

• The Journal of Korean Society for Radiation Therapy
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• v.34
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• pp.31-42
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• 2022

Purpose: This study measures and compares the surface dose values in the virtual target volume using Tomotherapy, Halcyon, and TrueBeam equipment using 6MV-Flattening Filter-Free(FFF) energy. Materials and Methods: CT scan was performed under three conditions of without bolus, 0.5 cm bolus, and 1 cm bolus using an IMRT phantom (IBA, Germany). The Planning Target Volume (PTV) was set at the virtual target depth, and the treatment plan was established at 200 cGy at a time. For surface dosimetry, the Gafchromic EBT3 film was placed in the same section as the treatment planning system and repeated measurements were performed 10 times and then analyzed. Result: As a result of measuring the surface dose for each equipment, without, 0.5 cm, 1 cm bolus is in this order, and the result of Tomotherapy is 115.2±2.0 cGy, 194.4±3.3 cGy, 200.7±2.9 cGy, The result in Halcyon was 104.7±3.0 cGy, 180.1±10.8 cGy, 187.0±10.1 cGy, and the result in TrueBeam was 92.4±3.2 cGy, 148.6±5.7 cGy, 155.8±6.1 cGy, In all three conditions, the same as the treatment planning system, Tomotherapy, Halcyon, TreuBeam was measured highly in that order. Conclusion: Higher surface doses were measured in Tomotherapy and Halcyon compared to TrueBeam equipment. If the characteristics of each equipment are considered according to the treatment site and treatment purpose, it is expected that the treatment efficiency of the patient will increase as well as the treatment satisfaction of the patient.

• Journal of Plant Biotechnology
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• v.50
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• pp.82-88
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• 2023

Shoot-tip culture was used to produce clonal plants of radish stock seeds. Using 6-benzyladenine (BA), the largest number of RA2 line multi-shoots were formed with an average of 14.67 shoots on 1.33 µM BA in early seedlings and 11.33 shoots on 1.78 µM BA in juvenile seedlings. The largest number of RA4 line multi-shoots were formed with an average of 11.67 shoots on 2.22 µM BA in early seedlings and 13.67 shoots on 1.33 µM BA in juvenile seedlings. There was little difference in the significance level by BA concentration in both lines. Using Thidiazuron (TDZ), the number of RA2 line multi-shoots increased with increasing TDZ concentration, forming the largest number of multi-shoots in 0.45 µM TDZ (7.0 and 3.0 multi-shoots for early and juvenile seedlings, respectively), but few multi-shoots were formed from TDZ 2.25 and 4.5 µM. RA4 line produced almost no multi-shoots in early seedlings, and 3.7 multi-shoots were produced in 0.23 and 0.45 µM TDZ in juvenile seedlings, but not at higher concentrations. Analysis of the tissue culture seedlings grown by cultivating the generated multi-shoots with Radish Foundation seeds using SSR marker revealed a weak pattern of mutation in the generated tissue culture seedlings, but there was no mutant. In addition, in terms of root roots, both RA2 and RA4 lines generally had the best rooting, number of roots, and degree of root development in 4.9 µM indol-3- butyric acid (IBA).

• Korean Journal of Weed Science
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• v.9 no.1
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• pp.56-68
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• 1989

aA series of experiments were conducted to investigate the effect of plant growth regulator treatments on the growth and lateral root formation in soybean sprouts in order to establish the effective method of producing root-less or short-rooted soybean sprouts with larger diameter in the hypocotyl. Major results can be summarized as follows. 1. Soybean sprouts showed fairly uniform elongation rate from 3 to g days after imbibition with daily increase of 3.8cm. The speed of elongation of hypocotyl was reduced whereas that of root accelerated 7 days after imbibition. Lateral roots began to emerge fairly evenly from 5 to 9 days after imbibition with a daily increase of 4.4. 2. Auxins(IAA, IBA, NAA, 2,4-D) inhibited hypocotyl elongation and formation of lateral roots and increased hypocotyl diameter without influencing root length and hook diameter at higher concentrations. The dry weight of cotyledon was increased significantly as compared to that of hypocotyl and root. Among the tested auxins, 2, 4-D was the most effective. 3. BA and 4PU-30 significantly reduced elongation of hypocotyl and root and resulted in the biggest diameter of hypocotyl when treated at higher concentrations. The lowest effective concentration of BA to prevent the formation of larval gal roots was 12.5ppm. The formation of lateral roots could be completely prevented by BA and 4PU-30 treatment but kinetin, zeatin, zeatin riboside resulted in many lateral roots and increased thickness of soybean sprouts with little influence. Cotyledon deformation was found in soybean sprouts treated by 4PU-30. 4. 2, 4-D was the most effective for increasing the hypocotyl diameter while 4PU-30 was the most effective for reducing no. of lateral roots. 5. It can be concluded that among the plant growth regulators tested, BA was effective in reducing root length and increasing hypocotyl diameter. BA 12.5 ppm or 15 ppm may thus be the more practical for production of soybean sprouts. 6. ABA showed no significant effect of growth parameter, however ABA 25 ppm inhibited only no of lateral roots with little influence on the growth of seedling. 7. Ethephon inhibited the elongation of hypocotyl and root and increased hypocotyl diameter at higher concentrations. 8. The combined effect of cytokinins and ethephon was very similar to result of BA treatment alone. As the ethephon concentration increased, hypocotyl diameter and dry weight of cotyledon tended to increase.

• The Journal of Korean Society for Radiation Therapy
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• v.26 no.1
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• pp.29-35
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• 2014

Purpose : This study has already started commercial Gated RapidArc automation equipment which was not previously in the Gated radiation therapy can be performed simultaneously with the VMAT Gated RapidArc radiation therapy to the accuracy of the analysis to evaluate the usability, Amplitude mode applied to the patient. Materials and Methods : The analysis of the distribution of radiation dose equivalent quality solid water phantom and GafChromic film was used Film QA film analysis program using the Gamma factor (3%, 3 mm). Three-dimensional dose distribution in order to check the accuracy of Matrixx dosimetry equipment and Compass was used for dose analysis program. Periodic breathing synchronized with solid phantom signals Phantom 4D Phantom and Varian RPM was created by breathing synchronized system, free breathing and breath holding at each of the dose distribution was analyzed. In order to apply to four patients from February 2013 to August 2013 with liver cancer targets enough to get a picture of 4DCT respiratory cycle and then patients are pratice to meet patient's breathing cycle phase mode using the patient eye goggles to see the pattern of the respiratory cycle to be able to follow exactly in a while 4DCT images were acquired. Gated RapidArc treatment Amplitude mode in order to create the breathing cycle breathing performed three times, and then at intervals of 40% to 60% 5-6 seconds and breathing exercises that can not stand (Fig. 5), 40% While they are treated 60% in the interval Beam On hold your breath when you press the button in a way that was treated with semi-automatic. Results : Non-respiratory and respiratory rotational intensity modulated radiation therapy technique absolute calculation dose of using computerized treatment plan were shown a difference of less than 1%, the difference between treatment technique was also less than 1%. Gamma (3%, 3 mm) and showed 99% agreement, each organ-specific dose difference were generally greater than 95% agreement. The rotational intensity modulated radiation therapy, respiratory synchronized to the respiratory cycle created Amplitude mode and the actual patient's breathing cycle could be seen that a good agreement. Conclusion : When you are treated Non-respiratory and respiratory method between volumetric intensity modulated radiation therapy rotation of the absolute dose and dose distribution showed a very good agreement. This breathing technique tuning volumetric intensity modulated radiation therapy using a rotary moving along the thoracic or abdominal breathing can be applied to the treatment of tumors is considered. The actual treatment of patients through the goggles of the respiratory cycle to create Amplitude mode Gated RapidArc treatment equipment that does not automatically apply to the results about 5-6 seconds stopped breathing in breathing synchronized rotary volumetric intensity modulated radiation therapy facilitate could see complement.

• Korean Journal of Heritage: History & Science
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• v.37
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• pp.65-89
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• 2004

Up to now, the studies for a pond of ancient palace of Korea are mainly achieved in a landscape architectural field. In fact, we can't grasp the general aspects but we are only heard about the fragmentary ruins and remains by the people who are in charge of an archaeological excavation. In this thesis, therefore, I attempt to grasp the relational categories of the ponds of an ancient palace of Korea, and find out the ideological backgrounds of the ponds of a palace construction through classify them excavated so far. The ancient ponds of Korea are divided to the class of square ponds(I) and curved ponds(II) according a shapes of planes. The class of square ponds(I) are subdivided to the form IA of the class of square ponds and form IB of the class of square ponds by whether it has an island, artificial hill and ornamental stone or not. And the class of the curved ponds(II) are divided to the form IIC that is only composed of curves in shore and the form IID that is composed of curves and straight lines. According the size, it is divided to a small size that is below the maximal diameter, 20m, and a large size that is more than 45m, after all, the ponds of the ancient palaces are devided to IAa, IAb, IBa, II Ca, IICb, IIDa. The square ponds and the curved ponds are co-exist from the initial stage when a pond of a place was found in our country and are succeeded or changed after Silla unified the three Kingdoms. In other words, we can infer a continuity from the earlier stage from the fact that there is a flat figure ground mainly constituted by the ponds of a palace mixed up of a straight line and a curved line in United Silla Kingdom while it succeeds the ponds of a palace that has a square form of Goguryo in Balhai. Different from the successional relation of the flat figure grounds, in an aspect of the elements of the construction, the site of the arbor at the top of the island and the bridge facilities in a field of a palace those are not exist in three Kingdoms period are appeared in United Silla Kingdom. The point that this aspect is simultaneously appeared in a neighboring country, or Japan, allows us to infer that there may be some motivations cause the changes in a construction of the ponds of a palace of Korea, China and Japan from the latter half of the 7th century to the first half of the 8th century. The ideological backgrounds of the ponds of a palace construction are divided roughly into Taoism and Buddhism. We can recognize that the ponds of a palace made up of the islands, the artificial hills and the garden rocks reflect Taiosm, considering the records of the ponds a palace of Korea and China are all use the term, Taoism, or the concrete statement represents that the islands, the artificial hills and the garden rocks are used in the description of the ponds of a palace of Korea. Both two are, therefore, obviously differentiated from the ponds of a palace that doesn't include them. We can conclude that the ponds of a palace that doesn't include them are colored by Buddhism since they are overtly distinguished from the class of curved ponds that reflect Taoism at the same period and they are identical with the site of an ancient temples in an aspect of their type and construction.

• Journal of Plant Biotechnology
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• v.44 no.1
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• pp.49-55
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• 2017

We investigated the callus induction and plant regeneration ability of 16 maize genotypes, including the Korean inbred lines, using 9 to 15 day-old immature zygotic embryos from maize grown in pots and from field cultures. Immature zygotic embryos placed on MS medium supplemented with L-proline 0.7 g/L, MES 0.5 g/L, Dicamba 1.5 mg/L, 2,4-D 0.5 mg/L, $AgNO_3$ 4 mg/L, and sucrose 20 g/L, showed the highest frequency of callus induction. The highest number of shoots regenerated when the embryogenic callus were transferred to MS medium supplemented with 5 mg/L zeatin. The root formation was observed when shoots were grown on MS medium supplemented with 0.2 mg/L indole-3-butyric acid (IBA). Additionally, under the same culture conditions, immature zygotic embryos from maize grown in the field also had a high frequency of plant regeneration. Except one genotype, 15 genotypes showed callus induction and shoot regeneration. Among the 16 genotypes tested, H99, B98, HW3, and B73 yielded the best plant regeneration. H99 showed maximum shoot formation from the primary embryogenic callus. The results suggest that genotypes and growth conditions of the maize plant plays very important roles for enhancing the embryogenesis competence of immature zygotic embryos. The successful regeneration from immature zygotic embryos of maize inbred lines provides a basis for molecular breeding of new cultivars by genetic transformation.

• Korean Journal of Medicinal Crop Science
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• v.8 no.1
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• pp.14-20
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• 2000

This experiment was conducted to investigate the effects of length of storage period under low temperature, $CO_2$ enrichment and addition of plant growth regulators in Murashige and Skoog medium on the plant regeneration of Korean ginseng (Panax ginseng C. A. Meyer). Seeds were treated for 60 and 80 days respectively under $5^{\circ}C$ environment. 2500ppm of $CO_2$ was enriched by ventilation. Three plant growth regulators added to the medium were Indolbutyric acid, Benzyladenin and Gibberellic acid (GA3). The result indicated that : The capacity of differentiation was higher in the aged cotyledons from the seeds treated for 80 days under low temperature condition than in those treated for 60 days. $CO_2$ enrichment had stimulating effects on the growth and development of shoot primordium significantly but less effects on the formation of adventitious buds. From one zygotic embryo hundreds of plantlets were differentiated. $CO_2$ enrichment had effects on the formation of both indirect somatic embryo and direct somatic embryo. Indirect somatic embryo showed little growth and differentiation, being undifferentiated vascular stele and epicotyl. Direct somatic embryos were formed on the epidermis of backside basal part of cotyledon. Those embryos developed to whole plant having latent bud.

• Applied Microscopy
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• v.36 no.2
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• pp.101-108
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• 2006

Myelin-associated glycoprotein (MAG) has been known to have a crucial role to the formation of myelin sheath during initial stage of myelination. In the present study, we investigated the aging-related expressional changes of MAG in the rat cerebrum. MAG expression was markedly decreased in cerebral cortex by aging. In the adult rat cerebrum, MAG-positive rolls were process-bearing cells with large nucleus, and extensively distributed. However, in the aged rat brain, MAG-positive cells showed small and round morphology with little cytoplasm and few processes. MAG was co-expressed with galatocerebroside, but not with Iba-1, or GFAP. These results suggest that the expressional change of MAG-positive cells is associated with degeneration of oligodendrocyte-myelin system by aging, and that MAG is likely to be a reliable marker for the mature oligodendrocytes in the aged rat brain.

• Korean Journal of Plant Tissue Culture
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• v.27 no.4
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• pp.309-315
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• 2000

Panax ginseng is an important medicinal plant that has been used worldwide for geriatric, tonic, stomachic, and aphrodisiac treatments. Ginsenosides contained in the ginseng root are the main substances having active functions for human body. The price of ginseng is very expensive due to a complex process of cultivation, and the yield of ginseng is limited, which cannot meet the demand of the increasing market. Researchers have applied plant biotechnology to solve the problems but there are still things to be determined towards ginsenoside production by large-scale adventitious root culture. In this experiment, 5 to 20 liter bioreactors were employed to determine optimal conditions for adventitious root culture and ginsenoside production of Panax gineng. Callus was induced from the ginseng root on MS agar medium containing 1.0 mg. $L^{-1}$ 2,4-D and 0.1 mg. $L^{-1}$ kinetin. Then the callus was cultured on MS agar medium supplemented with 2.0 mg. $L^{-1}$ IBA, 0.1 mg. $L^{-1}$ kinetin, and 30 g. $L^{-1}$ to induce adventitious roots. The maximum root growth and ginsenoside production were obtained in 1/2 MS medium. 2.0 mg. $L^{-1}$ naphthalene acetic acid resulted in greater root growth than 2.0 mg $L^{-1}$ indole-3-butyric acid. Ginsenoside content increased with 2.0 mg. $L^{-1}$ benzyl adenin or kinetin. High concentrations of benzyl adenin (above 3.0 mg. $L^{-1}$ ) decreased the adventitious root growth and ginsenoside productivity. N $H_{4}$$^{+}$ inhibited the ginsenoside accumulation, while high concentrations of $K^{+}$, $Mg_{2}$$^{+}$, and $Ca_{2}$$^{+}$ increased it. N $H_{4}$$^{+}$ at 0.5 and 1.0 times of the normal amount in 3/4 SH medium resulted in the greatest biomass increase, but the highest ginsenoside productivity was obtained when N $O_{3}$$^{-}$ was used as the sole nitrogen source in the medium. Most microelements at high concentrations in the medium inhibited the root growth, but high concentrations of MnS $O_4$enhanced the root growth. Root dry weight increased with increasing sucrose concentrations up to 50 g. $L^{-1}$ , but decreased from 70 g $L^{-1}$ Ginsenoside productivity was maximized at the range of 20 to 30 g. $L^{-1}$ sucrose. In the experiment on bioreactor types, cone and balloon types were determined to be favorable for both adventitious root growth and ginsenoside production. Jasmonic acid was effective for increasing ginsenoside contents and Rb group ginsenosides mainly increased. These results could be employed in commercial scale bioreactor cultures of Panax ginseng.x ginseng.