• The Journal of Engineering Geology
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• v.32 no.4
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• pp.483-498
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• 2022

Soil moisture is defined as water in the pores of the soil's unsaturated zone, and it is closely related to various hydrological processes. This study aims to provide meaningful data by identifying factors affecting soil moisture through comparing soil moisture content and soil permeability in a study area covering six different land use types in an agricultural region that is highly dependent on groundwater. We conduct auto-correlation analysis, spectral density analysis, and cross-correlation analysis using time-series data. Soil moisture content shows to have weak auto-correlation and memory effects, and precipitation appears to have a substantial influence on soil moisture content. Saturation hydraulic conductivity does not vary markedly with changing land use, and instead appears to be affected by the inhomogenous soil structure.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• v.25 no.6
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• pp.473-480
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• 2022

Purpose: Low bone mineral density (BMD) is a complication in children with inflammatory bowel disease (IBD). There are limited data evaluating dual-energy x-ray absorptiometry (DXA) as a screening tool for low BMD in children with IBD. We performed a single site retrospective analysis of DXA use. Methods: Children aged 5-18 years with IBD diagnosed between 2013 to 2017 at the Royal Children's Hospital, Australia, were included. Patient demographics, measures of disease activity, DXA scores, and factors related to BMD were collected. Results: Over a median follow up of 5.1 (4-6.4) years, 72/239 (30.1%) children underwent DXA, and 28/239 (11.7%) children had a second DXA. Our DXA practice differed to consensus guidelines regarding initial screening based on height and/or body mass index (BMI) z-score (8/17 [47.1%]), and repeat surveillance (13/42 [31.0%]). Children had a median lumbar spine (LS) z-score -0.80 (-1.65-0.075). Children with LS z-score≤-2.0 (n=14) had lower weight (6.57 [1.78-23.7] vs. 51.1 [26.5-68.7], p=0.0002) and height centiles (3.62 [1.17-17.1] vs. 42 [16.9-67.1], p=0.0001), and higher faecal calprotectin (FCP) (3041 [1182-4192] vs. 585 [139-2419], p=0.009) compared to children with LS z-score>-2.0. No fractures were reported. Of 28 children who underwent a second DXA 1.6 (1.1-2.2) years following initial DXA, no significant change in z-scores occurred. Conclusion: Children with IBD had low BMD. In addition to height centile and weight centile, FCP was associated with lower BMD, and should be considered in DXA screening guidelines. Greater clinician awareness of DXA consensus guidelines is required. Future prospective studies are required.

• Journal of Nutrition and Health
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• v.55 no.4
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• pp.450-461
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• 2022

Purpose: DNA damage and repair responses are induced by metabolic diseases and environmental stress. The balance of DNA repair response and the antioxidant system play a role in modulating the entire body's health. This study uses a high-fat and high-calorie (HFC) drink to examine the new roles of a plant-based multivitamin/mineral supplement with phytonutrients (PMP) for regulating the antioxidant system and cellular DNA repair signaling in the body resulting from metabolic stress. Methods: In a double-blind, randomized, parallel-arm, and placebo-controlled trial, healthy adults received a capsule containing either a PMP supplement (n = 12) or a placebo control (n = 12) for 8 weeks. Fasting blood samples were collected at 0, 1, and 3 hours after consuming a HFC drink (900 kcal). The blood samples were analyzed for the following oxidative stress makers: areas under the curve reactive oxygen species (ROS) levels, plasma malondialdehyde (MDA), erythrocytes MDA, urinary MDA, oxidized low-density lipoprotein, and the glutathione:oxidized glutathione ratio at the time points. We further examined the related protein levels of DNA repair signaling (pCHK1 (Serine 345), p-P53 (Serine 15), and 𝛄H2AX expression) in the plasma of subjects to evaluate the time-dependent effects of a HFC drink. Results: In a previous study, we showed that PMP supplementation for eight weeks reduces the ROS and endogenous DNA damage in human blood plasma. Results of the current study further show that PMP supplementation is significantly correlated with antioxidant defense. Compared to the placebo samples, the blood plasma obtained after PMP supplementation showed enhanced DNA damage response genes such as pCHK1(Serine 345) (a transducer of DNA response) and 𝛄H2AX (a hallmark of DNA damage) during the 8 weeks trial on metabolic challenges. Conclusion: Our results indicate that PMP supplementation for 8 weeks enhances the antioxidant system against oxidative stress and prevents DNA damage signaling in humans.

• Food Science of Animal Resources
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• v.42 no.5
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• pp.874-888
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• 2022

This study aimed to compare the similarities, physicochemical properties, and muscle fiber characteristics of porcine skeletal muscles. Fourteen types of muscles were collected from nine pig carcasses at 24 h post-mortem and classified by muscle architecture into two main groups, namely parallel and pennate. The muscles were further differentiated into three subtypes per group. These included fan-shaped, fusiform, and strap for the parallel group, and unipennate, bipennate, and multipennate for the pennate group. Parallel-fibered muscles, which were composed of larger I, IIA, IIX, and IIXB fibers and a lower density of IIA fibers, showed higher redness and yellowness values than pennate-fibered muscles (p<0.05). However, the relative fiber area was not significantly different between the parallel and pennate groups (p>0.05). In the subtypes of parallel architecture, the strap group showed lower moisture content and higher redness values than the other subtypes and had considerably higher amounts of oxidative fibers (I and IIA; 72.3%) than the fan-shaped and fusiform groups (p<0.05). In the pennate group, unipennate showed comparatively lower moisture content and higher lightness than other pennate subtypes and was composed of smaller I, IIA, and IIX fibers than the bipennate and multipennate groups (p<0.05). Finally, a different trend of muscle clustering by hierarchical cluster analysis was found between physicochemical properties and muscle fiber characteristics. These results suggest that the physicochemical properties and muscle fiber characteristics of porcine skeletal muscles are not significantly dependent on morphological properties but are rather related to the intrinsic properties of the individual muscles.

• Journal of architectural history
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• v.32 no.1
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• pp.73-88
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• 2023

Recently, local studies looking at the 'local(region) as a whole' are gradually increasing. The study of local architectural history is important in that it provides specific information that encompasses the local and the entire and clues to three-dimensionalize the time and space in the local. To infer the 'presentness' of each era, reliable data in various fields are needed. Recently, as many databases (DB) and archives, from the 'National Archives of Korea' to other local archives, have been established and publicized, research resources in the local are growing rapidly in quantity and quality. Nevertheless, it is difficult to comprehensively check the data necessary to study the local architectural history(local architectural history research resources). Against this background, this study confirmed the trend of changes in the archive construction environment and the status and problems of local architectural history research resources in places that currently disclose local history research resources among generalized web-archives. Next, the relationship between the actual research on local architectural history was confirmed through the analysis of existing studies and the data used for Jeju. As a result, local studies, local archives, and local architectural history research agree with recent changes in local research trends, and the degree of archival construction has reached the same level as the available research resources except core data in local architectural history research. However, there is a problem that the density of information that can be used is low because the local architectural history research resources that can be obtained are fragmented because there are no archives and construction entities specialized in local architecture. As each archive has entered the stabilization and upgrading stage, the construction of new archives needs to be reconsidered, but it is time to find a detailed way to link related information quickly and accurately, such as private records, to reduce the gap in information needed in terms of research on local architecture and architecture history.

• Journal of Powder Materials
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• v.29 no.6
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• pp.459-467
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• 2022

Soft magnetic powder materials are used throughout industries such as motors and power converters. When manufacturing Fe-based soft magnetic composites, the size and shape of the soft magnetic powder and the microstructure in the powder are closely related to the magnetic properties. In this study, Fe-Si-Al-P alloy powders were manufactured using various manufacturing process parameter sets, and the process parameters of the vacuum induction melt gas atomization process were set as melt temperature, atomization gas pressure, and gas flow rate. Process variable data that records are converted into 6 types of data for each powder recovery section. Process variable data that recorded minute changes were converted into 6 types of data and used as input variables. As output variables, a total of 6 types were designated by measuring the particle size, flowability, apparent density, and sphericity of the manufactured powders according to the process variable conditions. The sensitivity of the input and output variables was analyzed through the Pearson correlation coefficient, and a total of 6 powder characteristics were analyzed by artificial neural network model. The prediction results were compared with the results through linear regression analysis and response surface methodology, respectively.

• Journal of the Korean Society of Safety
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• v.38 no.2
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• pp.87-95
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• 2023

On October 29, 2022, a very large number of people gathered in Itaewondong, Yongsan-gu, Seoul, Korea for a Halloween festival, and as crowds pushed through narrow alleys, 159 deaths and 195 injuries occurred, making it the largest crushing incident in Korea. There have been a number of stampede deaths where crowds gathered at large-scale festivals, event venues, and stadiums, both at home and abroad. When the density increases, the physical contact between bodies becomes very strong, and crowd turbulence occurs when the force of the crowd is suddenly added from one body to another; thus, the force is amplified and causes the crowd to behave like a mass of fluid. When crowd turbulence occurs, people cannot control themselves and are pushed into he crowd. To prevent a stampede accident, investigation and management of areas expected to be crowded and congested must be systematically conducted, and related ministries and local governments are planning to establish a crowd management system to prepare safety management measures to prevent accidents involving multiple crowds. In this study, based on national data, a continuous digital topographic map is modeled in 3D to analyze the risk of crowding and present a plan for selecting high-risk walking routes. Areas with a high risk of crowding are selected in advance based on various data (numerical data, floating population, and regional data) in a realistic and feasible way, and the analysis is based on the visible results from 3D modeling of the risk area. The study demonstrates that it is possible to prepare measures to prevent cluster accidents that can reflect the characteristics of the region.

• Proceedings of the Korea Water Resources Association Conference
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• 2023.05a
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• pp.319-319
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• 2023

Flows of water in the environment (e.g. in a river or estuary) generally occur in complex conditions. This complexity can hinder a general understanding of flows and their related sedimentary processes, such as erosion and deposition. To gain insight in simplified, controlled conditions, hydraulic flumes are a popular type of laboratory research equipment. Linear flumes use pumps to recirculation water. This isn't appropriate for the investigation of cohesive sediments as pumps can break fragile cohesive sediment flocs. To overcome this limitation, the rotating annular flume (RAF) was developed. While not having pumps, a side-effect is that unwanted secondary circulations can occur. To counteract this, the top and bottom lid rotate in opposite directions. Furthermore, a larger flume is considered better as it has less curvature and secondary circulation. While only a few RAFs exist, they are important for theoretical research which often underlies numerical models. Many of the first-generation of RAFs have come into disrepair. As new measurement techniques and models become available, there is still a need to research cohesive sediment erosion and deposition in facilities such as a RAF. New RAFs also can have the advantage of being automatic instead of manually operated, thus improving data quality. To further advance our understanding of cohesive sediment erosion and deposition processes, a large, automatic RAF (1.72 m radius, 0.495 m channel depth, 0.275 m channel width) has been constructed at the Hydraulic Laboratory at Chungnam National University (CNU), Korea. The RAF has the ability to simulate both unidirectional (river) and bidirectional (tide) flows with supporting instrumentation for measuring turbulence, bed shear stress, suspended sediment concentraiton, floc size, bed level, and bed density. Here we present the current status and future prospect of the CNU RAF. In the future, calibration of the rotation rate with bed shear stress and experiments with unidirectional and bidirectional flow using cohesive kaolinite are expected. Preliminary results indicate that the CNU RAF is a valuable tool for fundamental cohesive sediment transport research.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.29 no.2
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• pp.129-138
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• 2023

The proportion of agricultural products handled through the Agricultural Products Processing Center (APC) is also steadily increasing every year, and in the case of Seongju Korean melon, a total of 10 APCs of Nonghyup and farming association corporations are in operation, and the distribution ratio is about 60% based on total production. In this study, Seongju Korean melon was selected as a target to analyze the environment load during carrying (production farm ~ APC) in the production area and the transport environment load during distribution of domestic fruits, and to analyze the environmental load for handling at APC. The vertical average vibration intensity (overall G_rms of 1~250 Hz) of truck transport measured at three transport routes from Seongju Korean melon producer ~ APC, Seongju ~ Seoul and Seongju ~ Jeju was about three times larger than that in the lateral direction and 4.5 times larger than that in the longitudinal direction, respectively. The frequency of occurrence of high-amplitude events (G) in the vertical direction compared to the measuring time was deeply related to pavement conditions in the order of unpaved farm-roads, concretepaved farm-roads, and asphalt-paved main-roads, but overall G_rms for the entire frequency band is believed to have a greater impact on vehicle traveling speed than road conditions. On the other hand, the difference in the size and direction of the vibration intensity measured by the forklift truck's main-body and the attachment (fork carrier) during handling at Seongju Korean melon APC was clear, and the vibration intensity of the forklift truck's main-body was largely affected by the stiffness of the fork and the mast according to the handling weight. Based on the field-data of the transport environment during domestic distribution measured through this study, it is believed that it is possible to develop a lab-based simulation protocol for appropriate packaging design.

• Atmosphere
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• v.33 no.4
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• pp.413-422
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• 2023

Urban Air Mobility (UAM) is promising, sustainable and efficient air transportation in a metropolitan area. Korean government has recently announced operation demonstration plans as a step toward commercialization of UAM. However, there is lack of understanding on the potential impact of weather on UAM operation. We collected weather observations from Gimpo International Airport and 5 automatic weather stations (AWS) along UAM corridor of the Han-River to assess weather barriers such as low visibility, wind gust and wind shear. The results show the frequency of low visibility near the corridor fluctuated significantly from year to year depending on the concentration of fine particulate matter (PM_2.5) in Seoul. The frequency of high wind speed-shift calculated using 1-minute wind observations was increased not only during the spring season (March, April, and May) but also the beginning of rainy season (Jun). In addition, a chance of high wind shear from 1-minute wind observations varied by the stations, suggesting that the condition is largely affected by topography including a river and high-rise buildings. These basic weather properties suggest that there are substantial weather barriers to UAM operations along the Han-River Corridor, while they cannot properly surveil micro-scale weather conditions in detail such as wind gust and wind shear over the corridor. Thus, this study suggests that potential barriers related to adverse weather need to be evaluated, building high-density weather observations infrastructure prior to UAM demonstration and commercialization.