• Nuclear Engineering and Technology
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• v.55 no.9
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• pp.3441-3449
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• 2023

We determined the radiation shielding properties for 10CaO-xPbO-(90-x) deteriorated silica gel (DSG) glass system (x = 20, 25, 30, 35, 40, and 45 mol.%). The mass attenuation coefficient (MAC) has been estimated at photon energies of 74.23, 97.12, 122, 662, 1173, and 1332 keV using a narrow beam X-ray attenuation and transmission experiment, the XCOM program, and a PHITS simulation. The obtained MAC values were applied to estimate the half value layer (HVL), mean free path (MFP), effective atomic number, and effective electron density. Results show that the MAC value of the studied glasses ranges between 0.0549 and 1.4415 cm²/g, increases with the amount of PbO, and decreases with increasing photon energy. The HVL and MFP values decrease with increasing PbO content and increase with increasing photon energy. The recycled glass, with the addition of PbO content (20-45 mol.%), exhibited excellent radiation shielding capabilities compared to standard barite and ferrite concretes and some glass systems. Moreover, the experimental radiation shielding parameters agree with the XCOM and PHITS values. This study suggests that this new waste-recycled glass is an effective and cost-saving candidate for X-ray and gamma-ray shielding applications.

• Applied Chemistry for Engineering
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• v.34 no.2
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• pp.121-125
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• 2023

Casein is a milk protein and one of the most important nutrients in milk. The composition is over 80% in cow's milk and about 20~45% in human's milk. Casein is highly biocompatible and biodegradable, so it has been studied for various biomedical materials applications as well as drug delivery systems. It is widely known that casein can be prepared as nanoparticles in the presence of the Ca²⁺ metal ion. Because casein is amphiphilic, hydrophobic drugs could be loaded inside to form a protein-based drug delivery system. In this study, we studied the optimum conditions for casein nanoparticle formation using natural metal ions present in the body, such as calcium, magnesium, zinc, and iron. It was confirmed that nanoparticles have a uniform size of around 150 nm and negative zeta potential values. In addition, it was demonstrated that casein nanoparticles have a cell viability of more than 80% and efficient intracellular uptake properties using confocal microscopy. From the results, it was also shown that the casein nanoparticles prepared using various metal ions have the potential to be biocompatible drug delivery carriers.

• The Journal of Korean Medicine
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• v.43 no.3
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• pp.181-194
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• 2022

Objectives: The purpose of this study is to investigate the effect of music therapy combined with hand manipulation on depression and cognition in elderly women with mild depression. Methods: In order to investigate the effects of a music therapy program through hand, 20 elderly women with a GDS-K score of 14-18 were selected among women aged 65 to 84 living in Busan. The 10 subjects in the experimental group were given the music therapy program 3 times a week for 4 weeks, 12 sessions, and the 10 subjects in the control group were not given it. GDS-K and K-MoCA were performed before and after the experiment, and data analysis was performed through Wilcoxon's test using the SPSS 24.0 statistical package program. Results: The music therapy program through hand manipulation is effective in reducing depression in elderly women with mild depression, and there was a significant decrease. The sub-domains of depression, such as tension and depressive emotions, life dissatisfaction, lethargy, cognitive difficulties, low energy, and loss of motivation, were significantly reduced. In addition, it has an effect on cognition, and it significantly increased in attention, delayed recall ability, which are sub-domains of cognition. There is a significant difference in depression between the experimental group and the control group, and there is a significant difference in cognition between the two groups. Conclusions: The music therapy program with hand manipulation has a positive effect on depression and cognition in elderly women with mild depression.

• Advances in concrete construction
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• v.15 no.3
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• pp.191-202
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• 2023

Palm oil fuel ash (POFA) is a newly emerging pozzolanic material having high amount of silica content. Various forms of POFA were used in cement-based materials (CBMs) in replacement of cement in different dosages of low and high volume. Although, there are many researches on POFA to be used in concrete and mortar, however, this material was not practically used in the construction industry. Engineers and designers need to be confident to use any new developed materials by knowing all engineering properties at short and long terms. As durability concern, concrete pH value is one of the most important properties. Portland cement produces are alkaline initially, however, it may be reduced due to aging and its components. It is believed that by incorporation of supplementary cementitious materials in CBMs the pH value reduces due to utilization of Ca(OH)₂ in pozzolanic reaction. This study is the first attempts to understand the pH value of mortars containing up to 30% POFA under different curing conditions and its changes with time. The results were also compared with the pH of ground granulated ballast furnace slag (GGBFS) and fly ash (FA) content mortars. In addition, the compressive strength of different mortars under different curing conditions were also studied. The results showed that the pH value of control mix (without cementitious materials) was more than all the blended cement mortars indifferent curing conditions at the same ages. However, there was a reducing trend in the pH value of all mortar mixes containing POFA.

• Korean Journal of Materials Research
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• v.32 no.3
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• pp.168-179
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• 2022

Microbiologically Influenced Corrosion (MIC) occurring in underground buried pipes of API 5L X65 steel was investigated. MIC is a corrosion phenomenon caused by microorganisms in soil; it affects steel materials in wet atmosphere. The microstructure and mechanical properties resulting from MIC were analyzed by OM, SEM/EDS, and mapping. Corrosion of pipe cross section was composed of ① surface film, ② iron oxide, and ③ surface/internal microbial corrosive by-product similar to surface corrosion pattern. The surface film is an area where concentrations of C/O components are on average 65 %/16 %; the main components of Fe Oxide were measured and found to be 48Fe-42O. The MIC area is divided into surface and inner areas, where high concentrations of N of 6 %/5 % are detected, respectively, in addition to the C/O component. The high concentration of C/O components observed on pipe surfaces and cross sections is considered to be MIC due to the various bacteria present. It is assumed that this is related to the heat-shrinkable sheet, which is a corrosion-resistant coating layer that becomes the MIC by-product component. The MIC generated on the pipe surface and cross section is inferred to have a high concentration of N components. High concentrations of N components occur frequently on surface and inner regions; these regions were investigated and Na/Mg/Ca basic substances were found to have accumulated as well. Therefore, it is presumed that the corrosion of buried pipes is due to the MIC of the NRB (nitrate reducing bacteria) reaction in the soil.

• The Bulletin of The Korean Astronomical Society
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• v.46 no.2
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• pp.46.3-47
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• 2021

Recently a multilayer spectral inversion (MLSI) model has been proposed to infer the physical parameters of plasmas in the solar chromosphere. The inversion solves a three-layer radiative transfer model using the strong absorption line profiles, H alpha and Ca II 8542 Å, taken by the Fast Imaging Solar Spectrograph (FISS). The model successfully provides the physical plasma parameters, such as source functions, Doppler velocities, and Doppler widths in the layers of the photosphere to the chromosphere. However, it is quite expensive to apply the MLSI to a huge number of line profiles. For example, the calculating time is an hour to several hours depending on the size of the scan raster. We apply deep neural network (DNN) to the inversion code to reduce the cost of calculating the physical parameters. We train the models using pairs of absorption line profiles from FISS and their 13 physical parameters (source functions, Doppler velocities, Doppler widths in the chromosphere, and the pre-determined parameters for the photosphere) calculated from the spectral inversion code for 49 scan rasters (~2,000,000 dataset) including quiet and active regions. We use fully connected dense layers for training the model. In addition, we utilize a skip connection to avoid a problem of vanishing gradients. We evaluate the model by comparing the pairs of absorption line profiles and their inverted physical parameters from other quiet and active regions. Our result shows that the deep learning model successfully reproduces physical parameter maps of a scan raster observation per second within 15% of mean absolute percentage error and the mean squared error of 0.3 to 0.003 depending on the parameters. Taking this advantage of high performance of the deep learning model, we plan to provide the physical parameter maps from the FISS observations to understand the chromospheric plasma conditions in various solar features.

• Journal of the Korean Society of Food Culture
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• v.24 no.6
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• pp.793-804
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• 2009

This study was conducted to investigate the change in the anthropometric values, biochemical index, nutritional knowledge, food habits and nutrient intakes in obese children after a weight control program. The subjects of the study were 22 obese children with an obesity index over 120%. The children that participated in this study took nutritional education for weight control along with exercise once a week. The weight control program was conducted for 10 weeks. The BMI, WHR (Waist-Hip ratio), body fat (%) significantly decreased at the end of the weight control program. Total cholesterol and LDL cholesterol were also significantly decreased. The nutritional knowledge scores and knowledge score about obesity were slightly improved. Energy intake significantly decreased from 1768 to 1421 kcal. Intake of Ca, Na, K, vitamin A, vitamin $B_6$, vitamin C and folate increased, while intakes of P, Zn, vitamin $B_1$, vitamin $B_2$, vitamin E and niacin decreased. The distribution of energy intake was significantly changed for the better. The percent fat consumed decreased from 26.5 to 19.7%. In addition, the distribution of energy intake in the meals was changed, where the percent calories consumed during lunch significantly increased from 31.4 to 40.1% and the calorie percentage consumed from snacks significantly decreased from 17.6 to 10.7%. In conclusion, the nutritional education in the weight control program, which was conducted for 10 weeks, was effective in improving the anthropometric values, biochemical index and nutrient intake although nutrition knowledge and eating behaviors only changed slightly. Thus, nutritional weight control programs for obese children should be continuously provided under the proper cooperation of a nutritional teacher at elementary schools.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2021.04a
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• pp.49-49
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• 2021

The roots of reed (Phragmites australis) were used in traditional medicine to treat respiratory problems, including symptoms such as high fever and cough. In this study, we identified the active ingredient from 70% EtOH reed root extract, and evaluated the whitening, wrinkle improvement and moisturizing effects. The content of p-coumaric acid, the active ingredient of the roots of P. australis, was slightly lower in 70% EtOH extract than in 100% EtOH extract. However, 70% EtOH reed root extract showed similar or higher effect in reducing power, DPPH, hydrogen peroxide scavenging, and nitric oxide scavenging activity compared to 100% EtOH extract. Moreover, 70% EtOH reed root extract markedly inhibited melanogenesis in B16F10 cells treated with α-melanocyte-stimulating hormone. 70% EtOH reed root extract significantly inhibited the mRNA expression of matrix metalloproteinase-1 (MMP-1) and reduced elastase activity in HDF human dermal fibroblasts. In addition, 70% EtOH reed root extract ameliorated hyaluronic acid synthase-2 (HAS-2) expression induced by ultraviolet B (UVB) stimulation in HaCaT keratinocytes. The results of this study suggest that 70% EtOH reed root extract has potential as a functional cosmetic material related to whitening, wrinkle improvement, and moisturizing.

• Journal of Powder Materials
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• v.30 no.5
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• pp.394-401
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• 2023

Li_1.5Al_0.5Ti_1.5(PO₄)₃ (LATP) is considered to be one of the promising solid-state electrolytes owing to its excellent chemical and thermal stability, wide potential range (~5.0 V), and high ionic conductivity (~10^-4 S/cm). LATP powders are typically prepared via the sol-gel method by adding and mixing nitrate or alkoxide precursors with chelating agents. Here, the thermal properties, crystallinity, density, particle size, and distribution of LATP powders based on chelating agents (citric acid, acetylacetone, EDTA) are compared to find the optimal conditions for densely sintered LATP with high purity. In addition, the three types of LATP powders are utilized to prepare sintered solid electrolytes and observe the microstructure changes during the sintering process. The pyrolysis onset temperature and crystallization temperature of the powder samples are in the order AC-LATP > CA-LATP > ED-LATP, and the LATP powder utilizing citric acid exhibits the highest purity, as no secondary phase other than LiTi₂PO₄ phase is observed. LATP with citric acid and acetylacetone has a value close to the theoretical density (2.8 g/cm³) after sintering. In comparison, LATP with EDTA has a low sintered density (2.2 g/cm³) because of the generation of many pores after sintering.

• Journal of the Korean Society of Industry Convergence
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• v.26 no.6_2
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• pp.1171-1181
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• 2023

In this study, a sweep gas - vacuum hybrid type membrane degassing process was proposed for ammonia wastewater treatment. In addition, the ammonia selective recovery of the hybrid type membrane degassing process was also investigated. As a result, the hybrid type membrane degassing process showed better degassing performance (54.9 mg NH₃/m²min for 360 min) than the sweep gas type (32.3 mg NH₃/m²min) or vacuum type (22 mg NH₃/m²min). Additionally, the hybrid type membrane degassing process showed an excellent ammonia selectivity (103 times compared to Na+ Na⁺, 133 times compared to Ca²⁺). The ammonia selectivity was appeared to be due to the conversion characteristics of ammonium ion / dissolved ammonia depending on pH. The results in this study are expected to be used in the development of ammonia wastewater treatment and ammonia recovery in the future.