• Journal of Environmental Health Sciences
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• v.49 no.5
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• pp.251-261
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• 2023

Background: This paper deals with the study of natural radioactivity in rocks from Ogun State in Southwestern Nigeria. The aim is to determine radiation emissions from rocks in order to estimate radiation hazard indices. Objectives: The following objectives were targeted: 1. To determine radiation emissions from each type of rocks; 2. To estimate radiation hazard indices based on the rocks; 3. To correlate the activity concentrations of radionuclides with major oxides. Methods: The samples were analyzed using a NaI (Tl) gamma ray spectrometric detector and PerkinElmer AAnalyst 400 AAS spectrometer. Results: The activity of ⁴⁰K, ²²⁶Ra, and ²³²Th were found in order of decreasing magnitude from pegmatite>granite>migmatite. In contrast, lower concentrations were found in shale, phosphate, clay stone, sandstone and limestone. The mean absorbed doses were 125±23 nGyh^-1 (migmatite), 74±13 nGy/h (granite), 72±13 nGyh^-1 (pegmatite), 64±09 nGyh^-1 (quartzite), 45±16 nGyh^-1 (shale), 41±09 nGyh^-1 (limestone), 41±11 nGyh^-1 (clay stone), 24±03 nGyh^-1 (phosphate), and 21±10 nGyh^-1 (sandstone). The outdoor effective dose rates in all rock samples were slightly higher than the world average dose value of 0.34 mSvy^-1. The percentage composition of SiO₂ in the rock samples was above 50 wt% except for in the limestone, shale and phosphate. Al₂O₃ ranged from 4.10~21.24 wt%, Fe₂O₃ from 0.39~7.5 wt%, and CaO from 0.09-46.6 wt%. In addition, Na₂O and K₂O were present in at least 5 wt%. Other major oxides, including TiO₂, P₂O₅, K₂O, MnO, MgO and Na₂O were depleted. Conclusions: The findings suggest that Ogun State may be described as a region with elevated background radiation. It is recommended that houses should be constructed with good cross ventilation and residences should use home radiation monitoring instruments to monitor radon emanating from walls.

• Korean Journal of Community Nutrition
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• v.28 no.6
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• pp.466-479
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• 2023

Objectives: A mobile health intervention program was provided for employees with overweight and obesity for 12 weeks, and a process evaluation was completed at the end of the program. We investigated participant engagement based on app usage data, and whether engagement was associated with the degree of satisfaction with the program. Methods: The program involved the use of a dietary coaching app and a wearable device for monitoring physical activity and body composition. A total of 235 employees participated in the program. App usage data were collected from a mobile platform, and a questionnaire survey on process evaluation and needs assessment was conducted during the post-test. Results: The engagement level of the participants decreased over time. Participants in their 40s, high school graduates or lower education, and manufacturing workers showed higher engagement than other age groups, college graduates, and office workers, respectively. The overall satisfaction score was 3.6 out of 5. When participants were categorized into three groups according to their engagement level, the upper group was more satisfied than the lower group. A total of 71.5% of participants answered that they wanted to rejoin or recommend the program, and 71.9% answered that the program was helpful in improving their dietary habits. The most helpful components in the program were diet records and a 1:1 chat with the dietary coach from the dietary coaching app. The barriers to improving dietary habits included company dinners, special occasions, lack of time, and eating out. The workplace dietary management programs were recognized as necessary with a need score of 3.9 out of 5. Conclusions: Participants were generally satisfied with the mobile health intervention program, particularly highly engaged participants. Feedback from a dietary coach was an important factor in increasing satisfaction.

• Journal of Life Science
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• v.33 no.10
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• pp.835-841
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• 2023

To determine the characteristics of propolis fermented with microorganisms, the optimal conditions for propolis extraction with ethanol were first reviewed, and the physicochemical properties of the extracted propolis were then investigated. The shaking and stationary extraction methods were tested. The flavonoid content was 6.40 mg/g when the stationary extraction method was used and 6.95 mg/g when the shaking extraction method was used. The ethanol concentration was then varied, and the use of 50, 60, 70, and 80% ethanol resulted in the total flavonoid content in the propolis samples reaching 6.75, 8.45, 7.45, and 7.75 mg/g, respectively. This indicated that a 60% (v/v) concentration was optimal. As the extraction time was increased from 1 to 3 hr, the flavonoid content slightly increased; however, extending the extraction step to more than 3 hr did not significantly affect the flavonoid content. In terms of the extraction temperature, the highest concentration of flavonoids (8.63 mg/g) was detected at 50℃. In the propolis samples, 5.80, 2.61, and 1.32 mg/g of fructose, sucrose, and rhamnose were detected, respectively. As for the amino acid content, 17 amino acids, including glutamic acid, were detected, and the total amino acid content was 2.49 mg/g.

• Korean Journal of Heritage: History & Science
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• v.56 no.4
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• pp.216-228
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• 2023

The purpose of this study is to apply the handheld Raman spectrometer to identify the coloring materials used in a large Buddhist painting (of Maitreya Buddha) at Janggoksa Temple through cross-validation with HH-XRF. An in situ investigation was performed together with use of a digital microscope and HH-XRF analysis to verify the properties of pigments used in the gwaebul ("large Buddhist painting") via a non-destructive method. However, the identification of coloring materials composed of light elements and mixed or overlaid pigments is difficult using only non-destructive analysis data. Unlike in situ investigation, laboratory analysis often required samples yet the sampling is restricted to a small quantity due to the cultural heritage characteristic. Thus, it is necessary to develop a non-destructive in situ method to supplement the HH-XRF data. The large Buddhist painting at Janggoksa Temple was painted mainly using white, red, yellow, green, and blue colors. The Raman spectroscopy provides molecular information, while XRF spectroscopy provides information about elemental composition of the pigments. Analysis results identified various coloring materials: inorganic pigment, such as lead white, minium, cinnabar, and orpiment, as well as organic pigment such as gamboge and indigo. Therefore, it is possible to obtain more information for the identification of pigments; organic pigment and mixed or overlaid pigments, while at the same time minimizing the collection sample and simplifying the analysis procedure compared to previously used methods. The results of this study will be used as basic data for the analysis of painting cultural heritage through a non-destructive in situ method in the future.

• Clean Technology
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• v.29 no.4
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• pp.305-312
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• 2023

Due to the strengthening of environmental requirements, aging denitrification facilities need to improve their performance. The present study aims to suggest the possibility of improving performance using computational analysis techniques. This involved modifying both the geometric design and the operating conditions, including the flow path shape of the equipment such as the inlet guide vane and the curved diffusing part, and the flow control of the ammonia injection nozzle. The conditions presented in this study were compared with existing operating conditions in terms of the flow uniformity, the NH₃/NO molar ratio of the mixed gas flowing into the catalyst layer, and the total pressure drop of the facility. The flow field applied in the computational analysis ranged from the outlet of the economizer in the combustion furnace to the inlet of the air preheater, the full domain of the denitrification facility. The performances were derived by solving the flow fields using ANSYS-Fluent and the injection amount of ammonia was adjusted for each nozzle using Design Xplorer. Compared to the denitrification performances of the equipment currently in operation, the conditions proposed in this study showed an improvement in the flow uniformity and NH₃/NO composition ratio by 45.1% and 8.7%, respectively, but the total pressure drop increased by 1.24%.

• Korean Journal of Radiology
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• v.23 no.5
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• pp.555-565
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• 2022

Objective: To assess the efficacy and safety of ultrasound (US)-guided radiofrequency ablation (RFA) in patients with primary hyperparathyroidism (PHPT). Materials and Methods: This prospective study enrolled 39 participants (14 male, 25 female; mean age, 59.5 ± 15.3 [range, 18-87] years) between September 1, 2018, and January 31, 2021. All participants had parathyroid lesions causing PHPT, proven biochemically and through imaging. The imaging features of the PHPT nodules, including the shape, margin, size, composition, and location, were evaluated before treatment. Serum intact parathyroid hormone, calcium, and phosphorus levels; parathyroid nodule volume; and PHPT-related symptoms were recorded before and after treatment. We calculated the technical success, biochemical cure, and clinical cure rates for these patients. Complications were evaluated during and after the ablation. Results: Complete ablation was achieved in 38 of the 39 nodules in the 39 enrolled participants. All the patients were treated in one session. The technical success rate was 97.4% (38/39). The mean follow-up duration was 13.2 ± 4.6 (range, 6.0-24.9) months. At 6 and 12 months post-RFA, the biochemical cure rates were 82.1% (32/39) and 84.4% (27/32), respectively, and the clinical cure rates were 100% (39/39) and 96.9% (31/32), respectively. Only 2.6% (1/39) of the patients had recurrent PHPT. At 1, 3, 6, and 12 months after technically successful RFA, 44.7% (17/38), 34.3% (12/35), 15.8% (6/38), and 12.5% (4/32) of participants, respectively, had elevated eucalcemic parathyroid hormone levels. Recurrent laryngeal nerve paralysis occurred in 5.1% (2/39) of the patients, who recovered spontaneously within 1-3 months. Conclusion: US-guided RFA was effective and safe for PHPT patients. RFA may be an alternative treatment tool for patients who cannot tolerate or refuse to undergo surgery.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.50 no.1
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• pp.13-26
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• 2024

Objectives: The aim of this study was to perform a comparative analysis of the ultrastructural and chemical composition of sialoliths, tonsilloliths, and antroliths and to describe their growth pattern. Materials and Methods: We obtained 19 specimens from 18 patients and classified the specimens into three groups: sialolith (A), tonsillolith (B), and antrolith (C). The peripheral, middle, and core regions of the specimens were examined in detail by histology, micro-computed tomography (micro-CT), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy, and transmission electron microscopy (TEM). Results: In the micro-CT, group A showed alternating radiodense and radiolucent layers, while group B had a homogeneous structure. Group C specimens revealed a compact homogeneous structure. Histopathologically, group A showed a laminated, teardrop-shaped, globular structure. Group B demonstrated degrees of immature calcification of organic and inorganic materials. In group C, the lesion was not encapsulated and showed a homogeneous lamellar bone structure. SEM revealed that group A showed distinct three layers: a peripheral multilayer zone, intermediate compact zone, and the central nidus area; groups B and C did not show these layers. The main elemental components of sialoliths were O, C, Ca, N, Cu, P, Zn, Si, Zr, F, Na, and Mg. In group B, a small amount of Fe was found in the peripheral region. Group C had a shorter component list: Ca, C, O, P, F, N, Si, Na, and Mg. TEM analysis of group A showed globular structures undergoing intra-vesicular calcification. In group B, bacteria were present in the middle layer. In the outer layer of the group C antrolith, an osteoblastic rimming was observed. Conclusion: Sialoliths had distinct three layers: a peripheral multilayer zone, an intermediate compact zone and the central nidus area, while the tonsillolith and antrolith specimens lacked distinct layers and a core.

• Journal of Ecology and Environment
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• v.48 no.1
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• pp.32-48
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• 2024

Background: Longitudinal connectivity in river systems strongly affects biological components related to ecosystem functioning, thereby playing an important role in shaping local biodiversity and ecosystem health. Environmental DNA (eDNA)-based metabarcoding has an advantage of enabling to sensitively diagnose the presence/absence of species, becoming an efficient/effective approach for studying the community structure of ecosystems. However, little attention has been paid to eDNA-based biomonitoring for river systems, particularly for assessing the river longitudinal connectivity. In this study, by using eDNA we analyzed and compared species diversity and composition among artificial barriers to assess the longitudinal connectivity of the fish community along down-, mid- and upstream in the Hotancheon from the Geum River basin. Moreover, we investigated temporal variation in eDNA fish community structure and species diversity according to season. Results: The results of species detected between eDNA and conventional surveys revealed higher sensitivity for eDNA and 61% of species (23/38) detected in both methods. The results showed that eDNA-based fish community structure differs from down-, mid- and upstream, and species diversity decreased from down to upstream regardless of season. We found that there was generally higher species diversity at the study sites in spring (a total number of species across the sites [n] = 29) than in autumn (n = 27). Nonmetric multidimensional scaling and heatmap analyses further suggest that there was a tendency for community clusters to form in the down-, mid- and upstream, and seasonal variation in the community structure also existed for the sites. Dominant species in the Hotancheon was Rhynchocypris oxycephalus (26.07%) regardless of season, and subdominant species was Nipponocypris koreanus (16.50%) in spring and Odontobutis platycephala (15.73%) in autumn. Artificial barriers appeared to negatively affect the connectivity of some fish species of high mobility. Conclusions: This study attempts to establish a biological monitoring system by highlighting the versatility and power of eDNA metabarcoding in monitoring native fish community and further evaluating the longitudinal connectivity of river ecosystems. The results of this study suggest that eDNA can be applied to identify fish community structure and species diversity in river systems, although some shortcomings remain still need to be resolved.

• Journal of the Microelectronics and Packaging Society
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• v.31 no.1
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• pp.43-48
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• 2024

The discovery of a two-dimensional electron gas (2DEG) at the interface of LaAlO₃ (LAO) and SrTiO₃ (STO) substrates has sparked significant interest, providing a foundation for cutting-edge research in electronic devices based on complex oxide heterostructures. However, conventional methods for producing LAO thin films, typically employing techniques like pulsed laser deposition (PLD) within physical vapor deposition (PVD), are associated with high costs and challenges in precisely controlling the La and Al composition within LAO. In this study, we adopted a cost-effective alternative approach-solution-based processing-to fabricate LAO thin films and investigated their electrical properties. By adjusting the concentration of the precursor solution, we varied the thickness of LAO films from 2 to 65 nm and determined the sheet resistance and carrier density for each thickness. After vacuum annealing, the sheet resistance of the conductive channel ranged from 0.015 to 0.020 Ω·s^-1, indicating that electron conduction occurs not only at the LAO/STO interface but also into the STO bulk region, consistent with previous studies. These findings demonstrate the successful formation and control of 2DEG through solution-based processing, offering the potential to reduce process costs and broaden the scope of applications in electronic device manufacturing.

• Animal Bioscience
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• v.37 no.4
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• pp.709-717
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• 2024

Objective: Abnormally increased somatic cell counts (SCCs) in milk is usually a sign of bovine subclinical mastitis. Mutual interaction between the host and its associated microbiota plays an important role in developing such diseases. The main objective of this study was to explore the difference between cows with elevated SCCs and healthy cattle from the perspective of host-microbe interplay. Methods: A total of 31 milk samples and 23 bovine peripheral blood samples were collected from Holstein dairy cattle to conduct an integrated analysis of transcriptomic and metagenomics. Results: The results showed that Ralstonia and Sphingomonas were enriched in cows with subclinical mastitis. The relative abundance of the two bacteria was positively correlated with the expression level of bovine transcobalamin 1 and uridine phosphorylase 1 encoding gene. Moreover, functional analysis revealed a distinct alternation in some important microbial biological processes. Conclusion: These results reveal the relative abundance of Ralstonia and Sphingomonas other than common mastitis-causing pathogens varied from healthy cows to those with subclinical mastitis and might be associated with elevated SCCs. Potential association was observed between bovine milk microbiota composition and the transcriptional pattern of some genes, thus providing new insights to understand homeostasis of bovine udder.