• Korean Chemical Engineering Research
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• v.60 no.2
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• pp.282-288
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• 2022

Facial masks have become indispensable in daily life to prevent infection and spread through respiratory droplets in the era of the corona pandemic. To understand how effective two different types of masks (i.e., KF-94 mask and dental mask) are in blocking respiratory droplets, i) we preferentially analyze wettability characteristics (e.g., contact angle and contact angle hysteresis) of filters consisting of each mask, and ii) subsequently observe the dynamic behaviors of microdroplets impacting at high velocities on the filter surfaces. Different wetting properties (i.e., hydrophobicity and hydrophilicity) are found to exhibit depending on the constituent materials and pore sizes of each filter. In addition, the pneumatic conditions for stably and uniformly dispensing microdroplets with a certain volume and impacting behaviors associated with the impacting velocity and filter type change are systematically explored. Three distinctive dynamics (i.e., no penetration, capture, and penetration) after droplet impacting are observed depending on the type of filter constituting the masks and droplet impact velocity. The present experimental results not only provide very useful information in designing of face masks for prevention of transmission of infectious respiratory diseases, but also are helpful for academic researches on droplet impacts on various porous surfaces.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.50 no.3
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• pp.201-211
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• 2024

The aim of this study was to propose Rosa multiflora (R. multiflora) as a cosmetic material for refining pores, and the ethanolic extract of R. multiflora (RME) was used to identify changes in various factors related to sebum regulation, astringency, and extracellular matrix, which are known to affect pores, and the effects were confirmed through clinical trials. The effects of these changes were confirmed through clinical trials. As a result, RME suppresses the excessive production of sebum, and it possesses DPPH radical scavenging ability through an astringent tannin component. Futhermore, RME inhibited 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1) activity and matrix metalloproteinase-1 (MMP-1) production, and it increased hyaluronic acid synthesis. In clinical trials, it was confirmed that RME significantly reduced the area, depth, number, volume, and density of pores-key parameters for assessing pores-and it also reduced sebum levels. This suggests that RME has an astringent effect and could be used as a cosmetic ingredient to improve the appearance of pores by controlling sebum production and influencing ECM-related factors.