• Progress in Medical Physics
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• v.15 no.1
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• pp.17-22
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• 2004

Multileaf collimator (MLC) is now rapidly replacing the lead ahoy block to shape the radiation treatment field. In addition to its defect of rectangular field shaping and increased penumbra width, it has another possible problem, and that is of radiation transmission between leaves, which needs to be maintained at as low a level as is permissible. The authors measured and analyzed the inter-leaf and cross-leaf transmissions of MLC by Varian Associates Inc, before its clinical application. The inter-leaf and cross-leaf transmissions were calculated by comparing the measured point doses in the polystyrene phantom in the open field and in a total closure of MLC. The beam profile of the inter-leaf and cross-leaf transmissions were depicted by using a water phantom. A photon beam of 6 MV was used in the measurement. The inter-leaf transmission was 1.63∼1.67%, indicating that the shielding effect of MLC is excellent. However, the cross-leaf transmission in the central area was 18.4∼18.7% and this is well over the clinically acceptable limitation of 5%. The beam profile of cross-leaf transmission displayed 80∼90% transmission near the field edge, so that the cross-leaf transmission was 14∼17% in this area. The multileaf collimator has an excellent shi디ding effect and the inter-leaf transmission is negligible so that it can be used in clinic as a good replacement of the conventional lead alloy block. However, care must be taken to avoid the cross-leaf transmission in the radiation field.

• Bulletin of the Korean Chemical Society
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• v.32 no.2
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• pp.625-629
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• 2011

A quantitative analysis of the decreasing rate of the monomer and increasing rate of the polymerization was made by monitoring radiation level increments using Raman spectroscopy within the therapeutic radiation range for a normoxic polymethacrylic acid gel dosimeter. The gel dosimeter was synthesized by stirring materials such as gelatin, distilled water, methacrylic acid, hydroquinone and tetrakis phosphonium chloride at $50^{\circ}C$, and the synthesized gel was contained in a 10- mm diameter and 32-mm high vial to conduct measurement. 24 hours after gel synthesis, it was irradiated from 0 Gy to 20 Gy by 2 Gy using a Co-60 radiotherapy unit. With use of the Cryo FE-SEM, structural changes in the 0 Gy and 10 Gy gel dosimeters were investigated. The Raman spectra were acquired using 532-nm laser as the excitation source. In accordance with fitting the changes in C-COOH stretching (801 $cm^{-1}$), C=C stretching (1639 $cm^{-1}$) and vinyl $CH_2$ stretching (3114 $cm^{-1}$) vibrational modes for monomer and $CH_2$ bending vibrational mode (1451 $cm^{-1}$) for polymer, sensitive parameter S for each mode was calculated. The values of S for monomer bands and polymer band were ranged in $6.0{\pm}2.6$ Gy and $7.2{\pm}2.3$ Gy, respectively, which shows a relatively good conformity of the decreasing rate of monomer and the increasing rate of polymerization within the range of error.

• Korean Journal of Pharmacognosy
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• v.38 no.1
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• pp.50-55
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• 2007

This study was designed to investigate the effects KH-204 on erectile dysfunction in hyperlipidemic rat. KH-204 has been evaluated antihyperlipidemic and antierectile dysfunction effects on experimental hyperlipidemic rats induced by high fat diet. After oral administration of the water extract KH-204 (50, 100, 200, 300 mg/kg) to hyperlipidemic rats for 8 weeks, the variables including body weight, total cholesterol, HDL and LDL levels in serum, the expression of eNOS and nNOS in penis were measured. And erectile function was determined by measurement of intracavernosal pressure (ICP) and maximal arterial pressure (MAP) after electrical stimulation of the cavernosal nerve. Oral administration of KH-204 significantly inhibited the increases of serum total cholesterol and LDL-cholesterol levels and the decreased of serum HDL-cholesterol levels in hyperlipidemic rats induced by high fat diet. The penile expression level of the two enzyme (eNOS, nNOS) were increased significantly after oral administration of the KH-204 50 mg/kg. Erectile function after 10 volts stimulation was significantly decreased in the hyperlipidemic rat compared with the normal rat, but increased in KH-204 group compared with hyperlipidemic group. These results suggest that KH-204 is effective for erectile dysfunction in hyperlipidemia.

• Progress in Medical Physics
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• v.29 no.2
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• pp.66-72
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• 2018

The proper position of a multi-leaf collimator (MLC) is essential for the quality of intensity-modulated radiation therapy (IMRT) and volumetric modulated arc radiotherapy (VMAT) dose delivery. Task Group (TG) 142 provides a quality assurance (QA) procedure for MLC position. Our study investigated the QA validation of the mechanical leaf gap measurement and the maintenance procedure. Two $VitalBeam^{TM}$ systems were evaluated to validate the acceptance of an MLC position. The dosimetric leaf gaps (DLGs) were measured for 6 MV, 6 MVFFF, 10 MV, and 15 MV photon beams. A solid water phantom was irradiated using $10{\times}10cm^2$ field size at source-to-surface distance (SSD) of 90 cm and depth of 10 cm. The portal dose image prediction (PDIP) calculation was implemented on a treatment planning system (TPS) called $Eclipse^{TM}$. A total of 20 VMAT plans were used to confirm the accuracy of dose distribution measured by an electronic portal imaging device (EPID) and those predicted by VMAT plans. The measured leaf gaps were 0.30 mm and 0.35 mm for VitalBeam 1 and 2, respectively. The DLG values decreased by an average of 6.9% and 5.9% after mechanical MLC adjustment. Although the passing rates increased slightly, by 1.5% (relative) and 1.2% (absolute) in arc 1, the average passing rates were still within the good dose delivery level (>95%). Our study shows the existence of a mechanical leaf gap error caused by a degenerated MLC motor. This can be recovered by reinitialization of MLC position on the machine control panel. Consequently, the QA procedure should be performed regularly to protect the MLC system.

• Asian Journal of Atmospheric Environment
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• v.7 no.4
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• pp.209-216
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• 2013

This study focused on a comprehensive and detailed interpretation for the springtime air quality influenced by both artificial (particulate matter (PM) and asbestos) and biological (pollen) sources in Fukuoka Prefecture, Japan. An intensive measurement of PM was conducted at four characteristic sites (i.e., a heavy traffic area, a residential area, an industrial area, and a desolate area) in the Fukuoka Prefecture during spring of 2007. Analysis of major ionic species in $PM_{2.5}$ was performed by an Ion Chromatography, and asbestos and pollen were identified by Scanning Electron Microscopy with an energy dispersive X-ray spectrometer (EDX). $PM_{2.5}$ concentration ($65.3{\mu}gm^{-3}$) measured in an industrial area (site C) was extraordinarily high compared to those monitored in other areas; it greatly exceeded the Japan's $PM_{2.5}$ criteria (a daily average of $35{\mu}gm^{-3}$). NOAA's HYSPLIT dispersion model suggests that this high level of $PM_{2.5}$ monitored at site C is unlikely to affect the Asian continent. The ambient concentrations of $PM_{2.5}$-related anions ($NH_4{^+}$, $NO_3{^-}$, and $SO_4{^{2-}}$) and their relative contributions to $PM_{2.5}$ were also investigated in four study areas. The concentrations of these major water-soluble ions exhibit not only strong spatial dependence but also different ratios to each other. Asbestos fiber (crocidolite and amosite) concentration values changed in the range of 2.5 to 14.4 f per liter of air. The number of pollen grains showed that Cedar ranked higher in concentration than other types of pollen, with the maximum concentration at site A.

• The Journal of the Acoustical Society of Korea
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• v.39 no.5
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• pp.390-399
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• 2020

Underwater ambient noise was measured at the eastern and western costal sites of Jeju Island where the water depth was 20 m by a hydrophone moored at mid-depth (10 m) for 4 months. These eastern and western sites were selected as potential sites for offshore wind power generator and the current wave energy generator, respectively. Ambient noise was affected by environmental data such as wind and wave, which were collected from nearby weather stations and an observation station. Below 100 Hz, ambient noise was changed about 5 dB ~ 20 dB due to low and high tide. Below 1 kHz, wave and wind effects were the main source for ambient noise, varying up to 25 dB. Ambient noise was strongly influenced by wave at lower frequency and by wind at higher frequency up to over 1 kHz. The higher frequency range over 10 kHz was influenced by rainfall and biological sources, and the spectrum was measured about 10 dB higher than the peak spectrum level from Wenz curve at this frequency range.

• The Journal of Korean Medicine
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• v.26 no.1 s.61
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• pp.103-114
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• 2005

Objective; Childhood obesity has become one of the most common health problems facing children in the world. Although a number of regimens have been developed and distributed for the treatment of adult obesity, few studies have focused on therapeutic programs for obese children. The objective of this study was to develop and measure the effects of Taeumin childhood obesity by a sasang constitution­based education program. Methods ; A total of 14$(\%RBW\geq20)$ among 18 taeumin with childhood obesity from June to August 2003 participated in the constitution-based education program. It was designed to examine the effects of a constitution-based education program through anthropometric measurements, body composition indicates, biochemical indicates and serum level of taeumin childhood obesity. Results; The results of this study were as follows: 1. The anthropometric measurement of subscapular skinfold thickness was reduced after 4 weeks of the constitution-based education program. 2. The body composition indicates reduction in degree of obesity, percent body fat, and fat distribution. The other side increased in height, total body water, soft lean mass, and lean body mass. 3. For biochemical indicates, HDL-cholesterol was increased significantly after 4 weeks of the constitution-based education program. The other side decreased in AST and ALT. 4. There was a significant reduction in BMI and $\%RBW$ after the constitution-based education program. Conclusion : A constitution-based education program for weight control results in reduced degree of obesity among taeumin children.

• Journal of the Korea institute for structural maintenance and inspection
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• v.19 no.6
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• pp.37-45
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• 2015

In this experimental study, effect of milled glass fibers was investigated on corrosion resistance of PSC grout mortar. In order to check whether the mortar mixture with milled glass fibers satisfy the required properties as a PSC grout, time of flow, bleeding and compressive strength measured. The corrosion resistance were investigated through chloride ion migration test, mortar absorption test and surface resistivity measurement. It is confirmed that all proportions with milled glass fibers have better corrosion resistance than that with only OPC binder. Time of flow was reduced but the bleeding was increased to unacceptable level by using milled glass fibers. Consequently, the mix proportion with milled glass fibers for a PSC grout should be modified to have lower water/binder ratio.

• YAKHAK HOEJI
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• v.58 no.1
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• pp.62-70
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• 2014

A 28-day repeated-dose oral toxicity test was performed to determine the no-observed-effect level (NOEL) and establish an optimum dose of the highly toxic Aconiti Ciliare Tuber (ACT) used as a folk remedy. Repeated oral doses of 1,250, 2,500, and 5,000 mg/kg/day of the hot water extract of ACT were administered to five male and five female Sprague-Dawley rats in each group for 4 weeks. The indicators for toxicity included results of examination of common symptoms and changes in weight and feed intake, eye test, urinalysis, hematological and serum biochemical analyses, and post-mortem weight measurement of organs, and visual inspections. All animals survived at the end of the experiment; in addition, we observed no specific test substance-mediated symptoms. We observed no test substance-mediated changes in body weight and feed intake. We observed statistically significant changes in male OB and pH levels (p<0.05). Further, the biochemical test showed statistically significant changes in the IP value of male rats and $CL^-$valueoffemalerats (p<0.05). However, all changes were within historical data. The post-mortem examinations showed no test substance-mediated changes. Moreover, statistically significant changes under the test conditions were confirmed to have been caused by factors other than the test substance. Thus, the maximum NOEL of ACT extract in rats was estimated to be 5,000 mg/kg/day.

• Journal of the Korea institute for structural maintenance and inspection
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• v.19 no.5
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• pp.67-74
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• 2015

RC (Reinforced Concrete) structures are considered as cost-benefit and durable however performances of structural safety and durability are degraded due to steel corrosion. Service life in RC structure is differently evaluated due to different local environmental conditions even if it is exposed to the same chloride attack. In the paper, 25 concrete cores from field investigation are obtained from 4 RC columns with duration of 3.5~4.5 years exposed to sea water. Through total chloride content measurement, surface chloride contents and apparent diffusion coefficients are evaluated. Service life of the target structure is estimated through deterministic method based on Fick's $2^{nd}$ Law and probabilistic method based on durability failure probability, respectively. Probability method is evaluated to be more conservative and relatively decreased service life is evaluated in tidal zone and splash zone over 40.0 m. Chloride penetration behavior with coring location from sea level and the present limitations of durability design method are investigated in the paper.