• Toxicological Research
• /
• v.17 no.2
• /
• pp.143-149
• /
• 2001

In the present study, we examined eye irritation oj six anti-wrinkle agents (ascorbic acid, glycolic acid, all trans-retinoic acid, ginseng extract, retinol, EB). We also compared eye irritation with skin irritation and cytotoxicity in HaCaT cells by these agents. The highest eye irritation was found in glycolic acid, but all trans-retinoic acid showed the highest skin irritation. The rank of eye irritation was not correlated with the cytotoxicity of agents. This result shows that eye irritation potency by these agents were not correlated with skin irritation potency, and cytotoxicity in HaCaT cells.

• Animal Bioscience
• /
• v.34 no.4
• /
• pp.533-538
• /
• 2021

Objective: Pluripotent stem cell-derived lymphatic endothelial cells (LECs) show great promise in their therapeutic application in the field of regenerative medicine related to lymphatic vessels. We tested the approach of forced differentiation of mouse embryonal stem cells into LECs using biodegradable poly lactic-co-glycolic acid (PLGA) nanospheres in conjugation with growth factors (vascular endothelial growth factors [VEGF-A and VEGF-C]). Methods: We evaluated the practical use of heparin-conjugated PLGA nanoparticles (molecular weight ~15,000) in conjugation with VEGF-A/C, embryoid body (EB) formation, and LEC differentiation using immunofluorescence staining followed by quantification and quantitative real-time polymerase chain reaction analysis. Results: We showed that formation and differentiation of EB with VEGF-A/C-conjugated PLGA nanospheres, compared to direct supplementation of VEGF-A/C to the EB differentiation media, greatly improved yield of LYVE1(+) LECs. Our analyses revealed that the enhanced potential of LEC differentiation using VEGF-A/C-conjugated PLGA nanospheres was mediated by elevation of expression of the genes that are important for lymphatic vessel formation. Conclusion: Together, we not only established an improved protocol for LEC differentiation using PLGA nanospheres but also provided a platform technology for the mechanistic study of LEC development in mammals.

• Clean Technology
• /
• v.29 no.1
• /
• pp.46-52
• /
• 2023

Oxalic acid has been traditionally obtained via the oxidation of carbohydrates using nitric acid and catalysts. However, this process produces a variety of nitrogen oxides during oxidation and requires a separation process due to its various intermediates. These products and additional steps increase the harmfulness and complexity of the process. Recently, the electrochemical reduction of carbon dioxide into oxalic acid has been suggested as an environmentally friendly and efficient technology for the production of oxalic acid. In this electrochemical conversion system, zinc oxalate (ZnC₂O₄) is obtained by the reaction of Zn²⁺ ions produced by Zn oxidation and oxalate ions produced by CO₂ reduction. ZnC₂O₄ can then be converted to form oxalic acid, but this requires the use of a strong acid and heat. In this study, a system was proposed that can easily convert ZnC₂O₄ to oxalic acid without the use of a strong acid while also allowing for easy separation. In addition, this proposed system can also further convert the products into glycolic acid which is a high-value-added chemical. ZnC₂O₄ was effectively separated into Zn(OH)₂ powder and oxalate solution through a chemical treatment and a vacuum filtration process. Then the Zn(OH)₂ and oxalate were electrochemically converted to zinc and glycolic acid, respectively.

• Proceedings of the KOR-BRONCHOESO Conference
• /
• 2002.12a
• /
• pp.10-10
• /
• 2002

• Molecules and Cells
• /
• v.44 no.12
• /
• pp.900-910
• /
• 2021

Sour is one of the fundamental taste modalities that enable taste perception in animals. Chemoreceptors embedded in taste organs are pivotal to discriminate between different chemicals to ensure survival. Animals generally prefer slightly acidic food and avoid highly acidic alternatives. We recently proposed that all acids are aversive at high concentrations, a response that is mediated by low pH as well as specific anions in Drosophila melanogaster. Particularly, some carboxylic acids such as glycolic acid, citric acid, and lactic acid are highly attractive to Drosophila compared with acetic acid. The present study determined that attractive carboxylic acids were mediated by broadly expressed Ir25a and Ir76b, as demonstrated by a candidate mutant library screen. The mutant deficits were completely recovered via wild-type cDNA expression in sweet-sensing gustatory receptor neurons. Furthermore, sweet gustatory receptors such as Gr5a, Gr61a, and Gr64a-f modulate attractive responses. These genetic defects were confirmed using binary food choice assays as well as electrophysiology in the labellum. Taken together, our findings demonstrate that at least two different kinds of receptors are required to discriminate attractive carboxylic acids from other acids.

• Proceedings of the Korean Fiber Society Conference
• /
• 1999.04a
• /
• pp.206-210
• /
• 1999

• Proceedings of the Korean Fiber Society Conference
• /
• 1991.06b
• /
• pp.58-60
• /
• 1991

• Proceedings of the Korean Fiber Society Conference
• /
• 1992.06a
• /
• pp.37-37
• /
• 1992

• Proceedings of the Korean Fiber Society Conference
• /
• 1992.06a
• /
• pp.38-38
• /
• 1992

• Journal of the Korean Society of Tobacco Science
• /
• v.24 no.2
• /
• pp.113-120
• /
• 2002

This study was conducted to determine the smoke component changes by adding oriental, reconstituted, and expanded tobacco leaves. 7 different cigarette brands which were mixed with flue-cured, burley, oriental, reconstituted and expanded tobacco leaves were used for this study. 64 kinds of smoke components which were 6 of general components, 34 of semi-volatile and volatile components, 9 of acid components, and 15 of phenolic components were analyzed. All smoke components of mainstream smoke were changed by the different branding. As Tar, nicotine, ammonia, pH, all of acid compounds(except lacatic and glycolic acid) were decreased; HCN, levoglucosame, 4-vinyl phenol, 4-vinyl catechol, quinic acid-r-lactone, acetaldehyde, 2,3-butadiene, stylene were increased by adding oriental tobacco leaves. When the reconstituted tobaccos were added to 20%, the concentration of nicotine, all of acid compounds(except lactic. glycolic, palmitic acid) and all of phenol compounds were reduced; the concentration of ammonia, HNC, CO, aeconitrile, benzene, 2-butanone, moth-acrolene, butyronitrile, stylene, o-xylene were increased. As decreasing ammonia, pH, nicotine, all of acid compounds, all of phenol compounds, Isoprene, acetonitrile, 2-methyl-2-butene, 1,3-pentadiene, 2-nlethyl furane, ethylene cyclopentanone, ethyl bezene; increasing CO concentration were followed by adding expanded tobacco leaves.