• BMB Reports
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• v.41 no.7
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• pp.529-536
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• 2008

Cinnamate-4-hydroxylase (C4H) is a key enzyme in the phenylpropanoid pathway, which is responsible for synthesizing a variety of secondary metabolites that participate in development and adaptation. In this study, we isolated a full-length cDNA of the C4H gene from the Korean black raspberry (Rubus sp.) and found that this gene existed as a single gene. By comparing the deduced amino acid sequence of Rubus sp. C4H with other sequences reported previously we determined that this sequence was highly conserved among widely divergent plant species. In addition, quantitative real time PCR studies indicated that the C4H gene had a differential expression pattern during fruit development, where gene expression was first detected in green fruit and was then remarkably reduced in yellow fruit, followed by an increase in red and black fruit. To investigate the two peaks in expression observed during fruit development and ripening, we measured the flavonoid content. The content of the major flavanol of Korean black raspberry fruits was determined to be highest at the beginning of fruit development, followed by a gradually decrease according to the developmental stages. In contrast, the content of anthocyanins during the progress of ripening was dramatically increased. Our results suggest that the C4H gene in Korean black raspberry plays a role during color development at the late stages of fruit ripening, whereas the expression of C4H gene during the early stages may be related to the accumulation of flavanols.

• Proceedings of the KSME Conference
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• 2004.04a
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• pp.1505-1509
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• 2004

A novel technique for fine particle beam focusing under the atmospheric pressure is introduced using a radiation pressure assisted aerodynamic lens. To introduce the radiation pressure in the aerodynamic focusing system, a 25 mm plano-convex lens having 2.5 mm hole at its center is used as an orifice. The particle beam width is measured for various laser power, particle size, and flow velocity. In addition, the effect of the laser characteristics on the beam focusing is evaluated comparing an Ar-Ion continuous wave laser and a pulsed Nd-YAG laser. For the pure aerodynamic focusing system, the particle beam width was decreased as increasing particle size and Reynolds number. For the particle diameter of 0.5 ${\mu}m$, the particle beam was broken due to the secondary flow at Reynolds number of 694. Using the Ar-Ion CW laser, the particle beam width becomes smaller than that of the pure aerodynamic focusing system about 16 %, 11.4 % and 9.6 % for PSL particle size of 2.5 ${\mu}m$, 1.0 ${\mu}m$, and 0.5 ${\mu}m$ respectively at the Reynolds number of 320. Particle beam width was minimized around the laser power of 0.2 W. However, as increasing the laser power higher than 0.4 W, the particle beam width was increased a little and it approached almost a constant value which is still smaller than that of the pure aerodynamic focusing system. The radiation pressure effect on the particle beam width is intensified as Reynolds number decreases or particle size increases relatively. On the other hand, using 30 Hz pulsed Nd-YAG laser, the effect of the radiation pressure on the particle beam width was not distinct unlike Ar-Ion CW laser.

• Journal of Magnetics
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• v.20 no.2
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• pp.103-109
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• 2015

In this study, the authors attempted to produce a medical radiation shielding fiber that can be produced at a nanosize scale and that is, unlike lead, harmless to the human body. The performance of the proposed medical radiation shielding fiber was then evaluated. First, diamagnetic bismuth oxide, an element which, among elements that have a high atomic number and density, is harmless to the human body, was selected as the shielding material. Next, 10-100 nm sized nanoparticles in powder form were prepared by ball milling the bismuth oxide ($Bi_2O_3$), the average particle size of which is $1-500{\mu}m$, for approximately 10 minutes. The manufactured bismuth oxide was formed into a colloidal solution, and the radiation shielding fabric was fabricated by curing after coating the solution on one side or both sides of the fabric. The thicknesses of the shielding sheets prepared with bismuth oxide were 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, and 1.0 mm. An experimental method was used to measure the absorbed dose and irradiation dose by using the lead equivalent test method of X-ray protection goods presented by Korean Industrial Standards; the resultant shielding rate was then calculated. From the results of this study, the X-ray shielding effect of the shielding sheet with 0.1 mm thickness was about 55.37% against 50 keV X-ray, and the X-ray shielding effect in the case of 1.0 mm thickness showed shielding characteristics of about 99.36% against 50 keV X-ray. In conclusion, it is considered that nanosized-bismuth radiation shielding fiber developed in this research will contribute to reducing the effects of primary X-ray and secondary X-ray such as when using a scattering beam at a low level exposure.

• Journal of Radiation Industry
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• v.10 no.4
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• pp.181-187
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• 2016

Selective ${\beta}_1$-agonist and antagonists are used for the treatment of cardiac diseases including congestive heart failure, angina pectoris and arrhythmia. Selective ${\beta}_1$-antagonists including nebivolol have high binding affinity on ${\beta}_1$-adrenergic receptor, not ${\beta}_2$-receptor mainly expressed in smooth muscle. Nebivolol is one of most selective ${\beta}_1$-blockers in clinically used ${\beta}_1$-blockers including atenolol and bisoprolol. We tried to develop clinically useful cardiac PET tracers using a selective ${\beta}_1$-blocker. Nebivolol is $C_2$-symmetric and has two chromane moiety with a secondary amino alcohol and aromatic fluorine. We adopted the general synthetic strategy using epoxide ring opening reaction. Unlike formal synthesis of nebivolol, we prepared two chromane building blocks with fluorine and iodine which was transformed to diaryliodonium salt for labelling of $^{18}F$. Two epoxide building blocks were readily prepared from commercially available chromene carboxylic acids (1, 8). Then, the amino alcohol building block (15) was prepared by ammonolysis of epoxide (14) followed by coupling reaction with the other building block, epoxide (7). Diaryliodonium salt, a precursor for $^{18}F$-aromatic substitution, was synthesized in moderate yield which was readily subjected to $^{18}F$-aromatic substitution to give $^{18}F$-labelled nebivolol.

• 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.

• Safety and Health at Work
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• v.13 no.4
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• pp.421-428
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• 2022

Background: The exposure to solar ultraviolet radiation is a significant risk factor generally underestimated by outdoor workers and employers. Several studies have pointed out that occupational solar exposure increased eye and skin diseases with a considerable impact on the lives and productivity of affected workers. The main purpose of this study was to evaluate the effectiveness against ultraviolet radiation of some measures recently undertaken for the protection of lifeguards in a coastal area of Tuscany. Methods: Different shading structures (gazebos and beach umbrella) were tested during a sunny summer's day on a sandy beach by means of two radiometers; the UV protection offered by some T-shirts used by lifeguards was also tested in the laboratory with a spectrophotometer. Results: The analysed shading structures strongly reduced the ultraviolet radiation by up to 90%, however a not always negligible diffuse radiation is also present in the shade, requiring further protective measures (T-shirt, sunglasses, sunscreen, etc.); the tested T-shirts showed a very good-excellent protection according to the Australian/New Zealand standard. Conclusion: Results obtained in this study suggest how the adoption and dissemination of good practices, including those tested, could be particularly effective as a primary prevention for lifeguards who are subjected to very high levels of radiation for long periods.

• The Journal of Korean Society for Radiation Therapy
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• v.8 no.1
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• pp.41-54
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• 1996

The secondary electrons developed by interaction between primary beam and a tray mounted for blocks in Megavoltage irradiation result in excess soft radiation dose to the surface layer. To reduce this electron contamination, electron filters have been used to be attached under a tray. Various filters with Cu and Al plates in six different thickness and Cu/Al combined plates in 3 different thickness were tested to measure the reduction rate of secondary electron contamination to the surface layer. The measurement to find optimal filter was performed on 6MV linear accelerator in $10 cm{\times}10 cm$ field size and fixed 78.5cm source to measurement points distance from surface to maximum build up point in 2mm intervals. The result was analyzed as the ratio of measured doses with using filters, to standard doses of measured open beam. The result of this study was fellowing : 1. The contaminated low energy radiation were mainly produced by blocking tray. 2. The surface absorbed dose was slowly increased by increasing irradiation field size but rapidly increased at field size above $15cm{\times}15cm$. 3. Al plate upto 2.5mm thickness used as a filter was found to be inadequate due to the failure of reduction of the surface absorbed dose below doses of the under surface upto the maximal build up. Cu 0.5mm plate and Cu 0.28mm/A1 1.5mm compound plate were found to be optimal filters. 4. By using these 2 filters, the absorbed dose to the surface were effectively reduced $5.5\%$ in field size $4cm{\times}4cm,\;11.3\%$ in field size $10cm{\times}10cm,\;22.3\%$ in field size $25cm{\times}25cm$. 5. In field size $10cm{\times}10cm$, the absorbed dose to the surface of irradiation was reduced by setting TSD 20cm at least,. but effective and enough dose reduction could be achieved by setting TSD 30cm as 2 optimal filters used. 6. More surface dose absorbed at TSD less than 7.4cm with a tray and filters together indicated that soft radiation was also developed by filters. 7. The variation of PDD by the different size of irradiation field was minimal as 2 optimal filters used. There was also not different in variation of PDD according to using any of two different filters. 8. PDD was not effected either by various TSD or by using the different filter among two.

• Journal of the Korean Society of Radiology
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• v.16 no.3
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• pp.357-363
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• 2022

This study aims to improve the safety inspection awareness of occupational exposure and help radiation safety management by analyzing radiation exposure doses by occupational type of radiation related-workers and radiation workers. Radiation-related workers and radiation workers were classified into three occupations (radiological technologist, doctors, and nurses). A nominal risk coefficient based on ICRP 103 was used to calculate the probability of causing side effects of the lungs due to exposure doses. As a result of analyzing the exposure dose of all workers for one year, the exposure dose of radiological technologist among radiation-related workers was 1.63 ± 2.84 mSv, doctors 0.12 ± 0.22 mSv, and nurses 0.59 ± 1.08 mSv. The one-year deep dose for radiation workers was 2.44 ± 3.30 mSv for radiological technologists, 0.19 ± 0.26 mSv for doctors, and 0.12 ± 0.00 mSv for nurses. Due to this dose, the probability of causing side effects in the lungs was 1.2 per 100,000 radiological technologist, 0.096 doctors, and 0.06 nurses. In this study, it is believed that the probability of side effects on lungs by occupation of radiation exposure dose will be studied and used as useful data for radiation safety management in relation to probabilistic effects in the future.

• Journal of Korean Neurosurgical Society
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• v.51 no.3
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• pp.144-146
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• 2012

Parkinsonism secondary to intracranial mass lesions usually results from compression or distortion of the basal ganglia. Secondary parkinsonism due to midbrain infiltration or compression is rare and generally associated with other neurologic signs caused by pyramidal tract and/or cranial nerve involvement. We report a case of 30-year-old woman in whom mild parkinsonism was the major clinical manifestation of an astrocytoma in the anterior third ventricle and hypothalamus. She underwent surgical resection, ventriculoperitoneal shunt and radiation therapy. All symptoms of parkinsonism were completely recovered 3 months after the treatment. Brain tumors can be manifested only by the symptoms of parkinsonism. This case emphasizes the significance of neuroimaging in the evaluation of parkinsonism.

• Journal of Energy Engineering
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• v.1 no.1
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• pp.76-86
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• 1992

A three-dimensional model has been developed for pulverized coal combusters and gasifiers. Coal devolatilization, heterogeneous char oxidation, gas particle interchange, radiation, gas phase oxidation, primary and secondary stream mixing, and heat losses are considered. A finite difference method was used to solve the ordinary non-linear differential equations. The effects of primary and secondary stream flow ratio and coal particle size are investigated.