Chung-Ang University

About: Chung-Ang University is a education organization based out in Seoul, South Korea. It is known for research contribution in the topics: Population & Thin film. The organization has 13381 authors who have published 26978 publications receiving 416735 citations. The organization is also known as: CAU & Chung.

Green synthesis of multi-color emissive carbon dots from Manilkara zapota fruits for bioimaging of bacterial and fungal cells.

Abstract: Natural resources have widely been used as precursors for the preparation of ultra-small carbon dots (C-dots) due to ease of availability, low cost and C-dots with high quantum yields (QYs). Herein, water dispersible multi-color emissive C-dots were obtained from Manilkara zapota fruits. The emission of C-dots was well tuned by sulphuric acid and phosphoric acids, which results to generate blue-, green- and yellow- C-dots. The fabricated C-dots exhibit blue, green and yellow color emissions when irradiated them under UV light at 365 nm. The emission/excitation peaks of blue-, green-, and yellow- C-dots were observed at 443, 515 and 563 nm when excited at 350, 420 and 440 nm, respectively. The QYs of blue-, green-, and yellow- C-dots are 5.7, 7.9 and 5.2%. The average sizes of blue- green- and yellow- C-dots are 1.9 ± 0.3, 2.9 ± 0.7and 4.5 ± 1.25 nm, respectively. Because of ultra-small size and biocompatibility, three C-dots act as promising bioimaging agents for imaging of cells (E. coli, Aspergillus aculeatus and Fomitopsis sp). The cytotoxicity on HeLa cells indicates that three C-dots have non-toxic nature, which confirms their biocompatibility. The ultra-small C-dots were effectively distributed in the cytoplasm of the cells, ensuring the potential applications in cell imaging and biomedical studies.

Bayesian network with quantitative input for maritime risk analysis

Abstract: This article presents an innovative approach towards integrating logistic regression and Bayesian networks (BNs) into maritime risk assessment. The approach has been developed and applied to a case study in the maritime industry, but has the potential for being adapted to other industries. Various applications of BNs as a modelling tool in maritime risk analysis have been widely seen in relevant literature. However, a common criticism of the Bayesian approach is that it requires too much information in the form of prior probabilities, and that such information is often difficult, if not impossible, to obtain in risk assessment. The traditional and common way to estimate prior probability of an accident is to use expert estimation (inputs) as a measure of uncertainty in risk analysis. In order to address the inherited problems associated with subjective probability (expert estimation), this study develops a binary logistic regression method of providing input for a BN, making use of different maritime acci...

The pepper lipoxygenase CaLOX1 plays a role in Osmotic, drought and high salinity stress response

Abstract: In plants, lipoxygenases (LOXs) are involved in various physiological processes, including defense responses to biotic and abiotic stresses. Our previous study had shown that the pepper 9-LOX gene, CaLOX1, plays a crucial role in cell death due to pathogen infection. Here, the function of CaLOX1 in response to osmotic, drought and high salinity stress was examined using CaLOX1-overexpressing (CaLOX1-OX) Arabidopsis plants. Changes in the temporal expression pattern of the CaLOX1 gene were observed when pepper leaves were treated with drought and high salinity, but not when treated with ABA, the primary hormone in response to drought stress. During seed germination and seedling development, CaLOX1-OX plants were more tolerant to ABA, mannitol and high salinity than wild-type plants. In contrast, expression of the ABA-responsive marker genes RAB18 and RD29B was higher in CaLOX1-OX Arabidopsis plants than in wild-type plants. In response to high salinity, CaLOX1-OX plants exhibited enhanced tolerance, compared with the wild type, which was accompanied by decreased accumulation of H2O2 and high levels of RD20, RD29A, RD29B and P5CS gene expression. Similarly, CaLOX1-OX plants were also more tolerant than wild-type plants to severe drought stress. H2O2 production and the relative increase in lipid peroxidation were lower, and the expression of COR15A, DREB2A, RD20, RD29A and RD29B was higher in CaLOX1-OX plants, relative to wild-type plants. Taken together, our results indicate that CaLOX1 plays a crucial role in plant stress responses by modulating the expression of ABA- and stress-responsive marker genes, lipid peroxidation and H2O2 production.

A subset of Arabidopsis RAV transcription factors modulates drought and salt stress responses independent of ABA

Abstract: Arabidopsis RAV1, RAV1L and RAV2/TEM2 are Related to ABI3/VP1 (RAV) transcription factors that contain both plant-specific B3 and AP2 domains. RAV1 was known to be a negative regulator of growth and its transcript level was repressed by brassinolide (BL). In this study, we found that the expressions of RAV1, and its closest homologs RAV1L and RAV2 were also regulated by other plant hormones, and especially repressed significantly by BL and abscisic acid (ABA), which mediate various abiotic stress responses in plants. Therefore, to further investigate the physiological functions of RAV1, RAV1L and RAV2 in abiotic stress responses, we isolated T-DNA insertional knockout mutants of each gene and produced transgenic plants overexpressing the RAVs. Under normal conditions, each single mutant showed slightly promoted growth patterns only at an early stage of development. In comparison, the RAV1-overexpressing plants exhibited strong growth retardation with semi-dwarfed stature. In drought conditions, RAVs-overexpressing transgenic plants exhibited higher transpirational water loss than the wild type. In salt conditions, seed germination of the RAVs-overexpressing transgenic plants was more inhibited than that of the wild type, while ravs mutants showed promoted seed germination. We also found that RAVs expressions were reduced by dryness and salt. RAV1-overexpressing plants showed the same patterns of increased expression as stress-inducible genes such as RD29A, RD29B and the genes encoding ABA biosynthetic enzymes, as did the wild type and rav1 mutant. However, the RAV1-overexpressing transgenic plants were insensitive to ABA, regardless of the higher accumulation of ABA even in normal conditions. Taken together, these results suggest that RAVs are versatile negative regulators for growth and abiotic stresses, drought and salt, and that negative regulatory effects of RAVs on abiotic stresses are likely to be operated independently of ABA.