• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.4
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• pp.413-418
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• 2021

Nano-materials with high effective surface areas have been applied to functional materials, such as high sensitive gas sensors and biosensors and high-efficiency catalytic materials. In this study, titanate sheets with a 3D nano-wall-like structure, high effective surface area, were synthesized vertically to the substrate by a chemical bath deposition (CBD) process using a Ti sheet and urea. The synthesis temperature and synthesis duration time were controlled to the optimal conditions of a 3D nano-wall-like structure in the CBD process. The synthesized ammonium titanate sheets with a 3D nano-wall-like structure were annealed in air to transform to TiO2 with a 3D nano-wall-like structure for various applications. As a result, the optimal temperature in the CBD process for the synthesis of a uniform ammonium titanate sheet with a 3D nano-wall-like structure was 90 ℃. TiO2 with a 3D nano-wall-like structure was obtained from the ammonium titanate sheet with a 3D nano-wall-like structure by annealing above 550 ℃ for three hours. In particular, TiO2 with a 3D nano-wall-like structure with a dominant rutile phase was obtained by post-annealing at 700 ℃. On the other hand, damage to the 3D nano-wall edge was observed after 700 ℃ post-annealing.

• The Korean Journal of Food And Nutrition
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• v.35 no.6
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• pp.453-463
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• 2022

This study aimed to investigate the biological activities, including polyphenolic content, flavonoid content, and antioxidant activities, of various cultivars of Korean perilla leaves. The results indicated that among nine cultivars (Namcheon dlggae, Saedora, Nulbora, Donggel 1, Donggell 2, Soim, Sangyeop, Somirang, and Saebom) of perilla leaves, the total polyphenolic content (gallic acid equivalent mg/g, GAE) was the highest in "Nulbora," while it was lowest in Namcheon dlggae. Moreover, flavonoid content in the extracts of nine cultivars leaves was in the range of 132.93~268.50 mg catechin equivalent/g sample. The antioxidant effects of the perilla leaves were determined using two different in vitro bioassays measuring DPPH and ABTS radical-scavenging activities. The results revealed that antioxidant activity was also higher in "Nulbora" compared with other cultivars. Xanthin-oxidase-inhibition activity ranged from 65.65% to 80.58%, with "Nulbora" exhibiting the highest activity, although the difference with other cultivars was not significant. "Nulbora" extracts reduced the expression of pro-inflammatory genes and several cytokines, including IL-6 activation induced by LPS in macrophages in the range of 100-50 ㎍/mL. These results suggest that extracts from perilla leaves can be used as bioactive and functional materials that could be important in industrial applications in the future.

• Applied Chemistry for Engineering
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• v.34 no.1
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• pp.23-29
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• 2023

Microfluidic reactors have been made to achieve significant development for the generation of new functional materials to apply in a variety of fields. Over the last decade, microfluidic reactors have attracted attention as a user-friendly approach that is enabled to control physicochemical parameters such as size, shape, composition, and surface property. Here, we develop a centrifugal microfluidic reactor that can control the flow of fluid based on centrifugal force and generate multifunctional particles of various sizes and compositions. A centrifugal microfluidic reactor is fabricated by combining microneedles, micro- centrifuge tubes, and conical tubes, which are easily obtained in the laboratory. Depending on the experimental control param- eters, including centrifuge rotation speed, alginate concentration, calcium ion concentration, and distance from the needle to the calcium aqueous solution, this strategy not only enables the generation of size-controlled microparticles in a simple and reproducible manner but also achieves scalable production without the use of complicated skills or advanced equipment. Therefore, we believe that this simple strategy could serve as an on-demand platform for a wide range of industrial and academic applications, particularly for the development of advanced smart materials with new functionalities in biomedical engineering.

• Korean Journal of Food Science and Technology
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• v.54 no.4
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• pp.422-430
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• 2022

The effects of phytase and cellulase treatment on the bioavailability of iron, calcium, and zinc in whole wheat flour and their food applications were evaluated in this study. Whole wheat flour was treated with phytase and cellulase either individually or in combination and incubated at 50℃ for 2 h; the concentrations used for the individual enzymes were 2%, 10%, and 20%. The concentration of the combination enzyme was 20% with a mixing ratio of 5:5. Total dietary fiber and phytate contents were reduced as the concentrations of phytase and cellulase increased. The bioavailability of iron, calcium, and zinc was notably improved after in vitro digestion in 20% cellulase, combination enzyme, and 20% phytase, respectively. Muffins made with cellulase- and phytase-treated whole wheat flour showed improved quality and bioavailability of minerals. Phytase- and cellulase-treated whole wheat flour may be useful for development of functional food products with improved bioavailability of minerals.

• Membrane Journal
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• v.33 no.4
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• pp.211-221
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• 2023

This study presents a comprehensive study on the synthesis and characterization of PVI-PGMA/LiTFSI polymeric membrane electrolytes and CxNy-C flexible electrodes for energy storage applications. The dual-functional PVI-PGMA copolymer exhibited excellent ionic conductivity, with the PVI-PGMA73/LiTFSI200 membrane electrolyte achieving the highest conductivity of 1.0 × 10^-3 S cm^-1. The electrochemical performance of the CxNy-C electrodes was systematically investigated, with C3N2-C demonstrating superior performance, achieving the highest specific capacitance of 958 F g^-1 and lowest charge transfer resistance (R_ct) due to its highly interconnected hybrid structure comprising nanowires and polyhedrons, along with binary Co/Ni oxides, which provided abundant redox-active sites and facilitated ion diffusion. The presence of a graphitic carbon shell further contributed to the enhanced electrochemical stability during charge-discharge cycles. These results highlight the potential of PVI-PGMA/LiTFSI polymeric membrane electrolytes and CxNy-C electrodes for advanced energy storage devices, such as supercapacitors and lithium-ion batteries, paving the way for further advancements in sustainable and high-performance energy storage technologies.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.36 no.4
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• pp.341-350
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• 2023

The templated grain growth (TGG) method has gained significant attention for its ability to produce highly textured piezoelectric ceramics with significantly enhanced performance, making it a promising method for transducer and actuator applications. However, the texturing process using the TGG method requires the optimization of multiple steps, which can be challenging for beginners in this field. Therefore, in this tutorial, we provide an overview of the TGG method mainly based on our previous published works, including its various processing steps such as synthesizing anisotropic-shaped templates with size and size distribution control using the molten salt synthesis technique, tape casting, and identifying key factors for proper alignment of the templates in the target matrix system. Our goal is to provide a resource that can serve as a basic reference for researchers and engineers looking to improve their understanding and utilization of the TGG method for producing textured piezoelectric ceramics.

• Journal of the Korean Society of International Agriculture
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• v.23 no.5
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• pp.497-502
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• 2011

Broccoli is considered as one of the functional foods to offer a hearty supply of the nutrient-rich vegetable in the world. Broccoli contains high level of phytochemicals, and that is selected as one of the top 10 vegetables for human health promotion. Especially, glucosinolates and flavonoids are well known as anti free oxygen radicals in vegetables and fruits. In Korea, broccoli consumption has increased to well known on the health-beneficial vegetables since 2000. However, broccoli has many problems of postharvest management since the quality of harvested heads quickly declines. Major problems are the floret yellowing, wilting, off-odor, and decay. The multiple postharvest applications improve broccoli quality and cold treatment including pre-cooling extends on the shelf-life with circumstance of optimum storage which is 0℃ temperature and a range of 95-100% relative humidity. Controlled atmosphere or modified atmosphere packaging can be used as supplemental treatments to extend postharvest life. 1-2% O₂ + 5-10% CO₂ is currently recommended for broccoli. Postharvest management is important for broccoli because price fluctuations depend on harvest time and quality. In this study, we tried to review physiological change of broccoli after the harvest, storage method, and various techniques to optimize quality during distribution.

• Food Science and Preservation
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• v.30 no.2
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• pp.358-368
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• 2023

Euonymus alatus (Thunb.) Sieb., also known as the arrow tree in Korea, is a plant in East Asia used in traditional medicine and food. In particular, the wings of E. alatus are rich in phenolic compounds. This study evaluated the antioxidant, α-glucosidase inhibition, and anti-cancer activities of E. alatus wing extracts. The radical and hydrogen peroxide scavenging acitvities and reducing the power of 1,000 ㎍/mL E. alatus wing extracts, were similar to those of the positive control (0.1% BHT, 0.1% α-tocopherol). In addition, ethanol and methanol extract at 250 ㎍/mL showed 95.70 and 94.99% of α-glucosidase inhibition activity, respectively. The ethanol extract of E. alatus wings had the highest total polyphenol and flavonoid contents (867.8 mg% and 521.7 mg%, respectively). The E. alatus wing extracts significantly decreased the cell viability of LNCaP human prostate cancer cells (p<0.001), MDA-MB-231 human breast cancer cells (p<0.001), and HT-29 human colon cancer cells (p<0.001) in a dose-dependent manner. However, there was no significant effect on B16 mouse melanoma cells. Notably, the ethanol extracts showed higher cancer cell growth inhibitory activity in LNCaP and HT-29 cells than the other extracts. These results suggest that E. alatus wing extracts could have significant clinical applications, and our results can be used as basic data for future functional food material development.

• Journal of Life Science
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• v.34 no.5
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• pp.296-303
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• 2024

Vinegar is a fermented food product created by fermenting various sugar- and starch-containing ingredients with microorganisms. It contains a variety of organic acids, sugars, amino acids, esters, and other compounds that contribute to its unique sensory properties. Vinegar is known for its potential benefits, including aiding digestion, lowering blood sugar levels, anti-obesity effects, and antioxidant properties. It is also believed to contribute to improving alkaline body conditions. This study was conducted to develop functional dried vinegar powder from naturally fermented vinegars. Unripe apple, brown rice, and black chokeberry (aronia) were fermented using Gluconacetobacter xylinus for 90-180 days. The filtrate vinegar was spray dried with 37.46% maltodextrin, 5% glucose, 1% citric acid, and 0.04% vitamin C. Analysis of the acidity, color difference, water and soluble solid content, and heat stability of dried vinegar (DV) confirmed that spray drying is a suitable method for powder production. Moreover, the DVs exhibited excellent sensory attributes and solubility. Among the DVs, aronia-DV showed the highest 1,1-diphenyl-2-picryl hydrazyl and 2,2-azobis (3- ethylbenzothiazoline-6-sulfonate) radical scavenging activity (36.7% and 75.3%) and reducing power (0.334) at 0.5 mg/ml concentration, respectively. The nitrite scavenging activity was highest in brown unripe apple-DV, followed by aronia-DV and brown rice-DV. In the anti-thrombosis activity assay, aronia-DV showed the highest prothrombin inhibition. The brown rice-DV exhibited lipid accumulation inhibitory activity in 3T3-L1 adipocytes without cell cytotoxicity. Our results suggest the potential for commercialization of dried vinegar, highlighting its diverse benefits and applications.

• Smart Media Journal
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• v.13 no.1
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• pp.36-44
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• 2024

Metaverse is attracting attention as the development of virtual environment technology and the emergence of untact culture due to the COVID-19 pandemic. In this study, by analyzing users' reviews on the "Zepeto" application, which has recently attracted attention as a metaverse service, we tried to confirm changes in the requirements for the metaverse after the COVID-19 pandemic. To this end, 109,662 reviews of "Zepeto" applications written on the Google Play Store from September 2018 to March 2023 were collected, topics were extracted using LDA topic modeling technique, and topics were analyzed using the Causal Impact technique to examine how topics changed before and after based on "March 11, 2020" when the COVID-19 pandemic was declared. As a result of the analysis, five topics were extracted: application functional problems (topic1), security problems (topic 2), complaints about cryptocurrency (Zem) in the application (topic 3), application performance (topic 4), and personal information-related problems (topic 5). Among them, it was confirmed that security problems (topic 2) were most affected by the COVID-19 pandemic.