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Korean EFL Learners’ Use of Formulaic Language
Yeonhwa Park,Mun-Hong Choe 언어과학회 2019 언어과학연구 Vol.0 No.88
This study aims to investigate the extent to which Korean EFL learners make use of formulaic language in comparison with that of English L1 speakers. With reference to the PHRASE List proposed by Martinez and Schmitt (2012), the corpora of speaking and writing samples of English L1 speakers and Korean EFL learners from the International Corpus Network of Asian Learners of English were analysed. The results show that Korean students use a comparatively small number of formulaic expressions, and use them far less frequently than L1 speakers in all the three categories examined: verb groups, modalization, and connectives. They also tend to use a few items overly frequently for an extended range of functions. These imply that formulaic language is an important factor in the variation and development of L2 communicative competence and therefore raising students’ awareness of its forms and functions should be an integral part of instruction.
Antioxidant Activity of Water Extract from Black Raspberry on C2C12 Muscle Cells
Yeonhwa Lee,Yunji Park,Jihye Choi,Jeongjin Park,Kyungmi Kim,Woojin Jun 한국식품영양과학회 2021 한국식품영양과학회 학술대회발표집 Vol.2021 No.10
Black raspberry (Rubus occidentalis) is black-fruited raspberry native to north america and known to have various activities. This study investigated the antioxidant activities and intracellular ROS level of water extract from black raspberry (ROW) on C2C12 cells. Antioxidant activity was evaluated by 2,2"-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTs) and 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activities. Total phenolic and flavonoid contents also measured. Intracellular ROS level was evaluated using DCF-DA method at concentrations of 200-500 μg/mL on H₂O₂-induced C2C12 myoblast cell. Intracellular ROS production showed higher level in the H₂O₂ treated group than control group and dose-dependent decrease in the sample group. These results suggest black raspberry water extract have antioxidant activity and effect against oxidative stress.
Bioactivities and Potential Mechanisms of Action for Conjugated Fatty Acids
Yeonhwa Park,Michael W. Pariza 한국식품과학회 2009 Food Science and Biotechnology Vol.18 No.3
Since conjugated linoleic acid (CLA) was identified as a principal anticancer component from ground beef in the 1980s, CLA research has discovered that CLA has a wide range of biologically beneficial effects. Clinical studies with CLA are on the rise, and it is apparent that CLA may not be as effective in humans as in rodents, in particular its anti-obesity aspect. In addition, research with regard to other conjugated fatty acids as well as CLA metabolites is still in its infancy. Investigation of bioactivities for other conjugated fatty acids and CLA metabolites may help to extend the understanding of CLA and its mechanisms of actions. This may pose an opportunity to use CLA more efficiently and expand the future use of other conjugated fatty acids as pharmacological agents to assist current treatments.
Yeonhwa Park 한국식품영양과학회 2021 한국식품영양과학회 학술대회발표집 Vol.2021 No.10
Oxidative stress is known to be contribute to the development of a range of adverse health conditions, including aging. Previously, three food bioactives were tested for their anti-aging properties in our group, using Caenorhabditis elegans. C. elegans is a multi-organ, microscopic, transparent roundworm, used in many scientific research, particularly significant in the field of aging, due to its short lifespan and many well-conserved aging and stress-related pathways to mammals. Three bioactives tested were; piceatannol, chicoric acid, p-coumaric acid. Picaetannol is a hydroxylated resveratrol derivative. Chicoric and p-coumaric acids are hydroxy derivatives of cinnamic acid. All are phenolic compounds that are widely distributed in plant foods with strong antioxidant properties, 15~38% reduction on internal reactive oxygen species, in C. elegans. All of these bioactives improved the worms’ survival under oxidative stress condition, further supporting antioxidant activity contributed to reduced oxidative stress responses in this model. Underlying mechanisms of regulation of oxidative stress was via sir-2.1 (encodes homolog of NAD-dependent deacetylase sirtuin-1, SIRT1) and daf-16 (encodes homolog of forkhead box O transcription factor, FoxO) for piceatannol, while via skn-1 (encodes homolog of nuclear factor erythroid 2-related factor 2, NRF2) for both chicoric and p-coumaric acids. Chicoric acid also activates aak-2 (encodes homolog of AMP-activated protein kinase a, AMPKa) for its antioxidative activities. However, their lifespan extension capacities were not the same; Piceatannol and chicoric acid extended lifespan compared to the control, while p-coumaric acid extended the lifespan only under oxidative stress conditions. These results suggest that antioxidative property itself may not be sufficient enough to extend the lifespan significantly. Further investigations are needed to evaluate the significance of these findings on aging including their role in healthspan.