• Journal of the Korean Applied Science and Technology
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• v.36 no.3
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• pp.853-865
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• 2019

In this study, the skin permeability was measured by adding skin penetrating peptides, arginine oligomers R4(tetra-D-arginine), R6(hexa-D-arginine) to little skin-permeable wrinkle improvement peptides GHK, GHK-Cu, and Pal-GHK liposomes, and the results were analyzed by the following six cases. (1) In cases where only wrinkle improvement peptides GHK, GHK-Cu, and Pal-GHK were contained liposomes; the final cumulative permeations in 24 hours were 6.05%, 7.4%, and 8.83% respectively. (2) In cases where arginine oligomers R4, R6 were added to GHK liposomes; the final cumulative permeations in 24 hours were 13.63% and 7.68%. (3) In cases where R4, R6 were added to GHK-Cu liposomes; the final cumulative permeations in 24 hours were 15.46% and 8.64%. (4) In cases where R4, R6 were added to Pal-GHK liposomes; the final cumulative permeations in 24 hours were 16.9% and 10.67%. (5) In cases where R4 were added to GHK, GHK-Cu, and Pal-GHK liposomes; the final cumulative permeations in 24 hours were 13.63%, 15.46%, and 16.9% respectively. (6) In cases where R6 were added to GHK, GHK-Cu, and Pal-GHK liposomes; the final cumulative permeations in 24 hours were 7.68%, 8.64%, and 10.67% respectively. This experiment showed that skin absorption of GHK was increased by copper ion (Cu2+) and palmitic acid and skin absorption of wrinkle improvement peptides was enhanced by cell penetrating peptides, and R4 showed higher effect than R6 in GHK, GHK-Cu and Pal-GHK. Through this process, we propose broad use and application in wrinkle improvement functional cosmetics by presenting the optimal conditions for increasing skin absorption of GHK, GHK-Cu, thus maximizing its efficacy.

• Journal of Life Science
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• v.31 no.8
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• pp.719-728
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• 2021

Melanin pigments are abundantly distributed in mammalian skin, hair, eyes, and nervous system. Under normal physiological conditions, melanin protects the skin against various environmental stresses and acts as a physiological redox buffer to maintain homeostasis. However, abnormal melanin accumulation results in various hyperpigmentation conditions, such as chloasma, freckles, senile lentigo, and inflammatory pigmentation. Tyrosinase, a copper-containing enzyme, plays an important role in the regulation of the melanin pigment biosynthetic pathway. Although several whitening agents based on tyrosinase inhibition have been developed, their side effects, such as allergies, DNA damage, mutagenesis, and cytotoxicity of melanocytes, limit their applications. In this study, we synthesized 4-chromanone derivatives (MHY compounds) and investigated their ability to inhibit tyrosinase activity. Of these compounds, (E)-3-(4-hydroxybenzylidene)chroman-4-one (MHY1294) more potently inhibited the enzymatic activity of tyrosinase (IC₅₀ = 5.1±0.86 μM) than kojic acid (14.3±1.43 μM), a representative tyrosinase inhibitor. In addition, MHY1294 showed competitive inhibitory action at the catalytic site of tyrosinase and had greater binding affinity at this site than kojic acid. Furthermore, MHY1294 effectively inhibited α-melanocyte stimulating hormone (α-MSH)-induced melanin synthesis and intracellular tyrosinase activity in B16F10 melanoma cells. The results of the present study indicate that MHY1294 may be considered as a candidate pharmacological agent and cosmetic whitening ingredient.

• Journal of the Korean Society of Radiology
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• v.17 no.5
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• pp.641-649
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• 2023

This study compares and analyzes the performance of a shield manufactured using 3D printing technology to find out its applicability as a shield in high-energy electron beam therapy. Actual measurement and monte carlo simulations were performed to evaluate the shielding performance of 3D printing materials for high-energy electron beams. First, in order to secure reliability for the simulation, a source term evaluation was conducted by referring to the IAEA's TRS-398 recommendation. Second, to analyze the shielding performance of PLA+W (93%), a specimen was manufactured using a 3D printer, and the shielding rate by thickness according to electron beam energy was evaluated. Third, the shielding thickness required for electron beam treatment was calculated through a comparative analysis of shielding performance between PLA+W (93%) and existing shielding bodies. First, as a result of the evaluation of the source term through actual measurement and simulation, the TRS-398 recommendation was satisfied with an error of less than 1%, thereby securing the reliability of the simulation. Second, as a result of the shielding performance analysis for PLA+W (93%), 6 MeV electron beams showed a shielding rate of more than 95% at 3.12 mm, and 15 MeV electron beams showed a shielding rate of more than 90% at 10 mm thickness. Third, through simulations, comparative analysis between PLA+W (93%) materials and existing shields showed high shielding rates within the same thickness in the order of tungsten, lead, copper, PLA+W (93%), and aluminum. 6 MeV electron beams showed almost similar shielding rates at 5 mm or more and 15 MeV electron beams. Through this study in the future, it is judged that it can be used as basic data for the production and application of shielding bodies using PLA+W (93%) materials in high-energy electron beam treatment.