• Transactions of Materials Processing
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• v.25 no.2
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• pp.130-135
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• 2016

Rolled products often have residual stresses or strip waves that are beyond the customer’s tolerance. To resolve this problem, skin-pass rolling is widely used during post-processing of such products. Because a short contact length compared to the strip width is a characteristic of skin-pass rolling, several numerical analyses have been previously conducted based on a two-dimensional approach. In the current study, a series of simulations was conducted using numerical analysis of three-dimensional elastic-plastic finite element method.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.38 no.1
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• pp.43-50
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• 2012

The safety of cosmetics or cosmetic ingredients on human skin is generally evaluated by visual assessment but some early subtle skin changes may not be noticed by the naked eyes. Thus, the present study was conducted to detect skin reactions induced by mildly irritating cosmetic ingredients by using a laser Doppler perfusion imager (LDPI) method that measures blood flow, a $Vapometer^{(R)}$ that measure strans epidermal water loss (TEWL), and a spectrophotometer that measures the skin color as the erythema values ($a^*$). Visual assessment showed that all tested oils and humectants except propylene glycol belong to the low skin irritation ranges (grades 0+ to 2.9+) while all tested surfactants and propylene glycol belong to the moderate-to strong-skin irritation ranges (grades 3+ to 5+). Among three instrumental methods, TEWL assessment appeared to be more sensitive than spectrophotometric or LDPI method and suitable for the detection of subtle skin response invisible to the naked eye (grades 0+ to 2.9+). Skin reactions of grade 3+ to 5+ could be detected by all three instrumental methods. In conclusion, the current study suggested that the sub-clinical skin reactions due to mild irritants contained in cosmetics can be best assessed by TEWL measurements.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.43 no.3
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• pp.189-194
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• 2017

Skin has a strong barrier function to protect the body from external harmful factors. This strong barrier function of the skin makes for any effective substance difficult to permeate through the skin. The purpose of this study was to evaluate skin permeability of the reduced particle size by non-invasive method. The particles were prepared by high-pressure emulsification. The niacinamide prepared in a high-pressure emulsification was absorbed 1.56 times higher than the control sample. In addition, it was found from the sixth layer of keratin that was removed by tape-stripping method. This was significantly deeper penetration. The whitening efficacy of the sample containing niacinamide was evaluated before and after 6 weeks of use. The skin color was significantly improved in both pigmented area and non-pigmented area. Through this study, it was possible to visually and quantitatively confirm the permeability confirm the permeability of the reduced particle sample into skin.

• Korean Journal of Poultry Science
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• v.19 no.1
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• pp.47-53
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• 1992

This study was carried out to determine the plasma vitamin $D_3$($D_3$) of 3 weeks old broiler chicks (Hubbard line), whose dorsal skin was exposed to different dose of 310 m UV light. The irradiated doses were 0~0.79 J/$\textrm{cm}^2$(6 doses$\times$5 replica＝30 chicks). The blood samples were collected 2 days after exposure. The lipid in plasma isolated was extracted with ethyl acetate. The $D_3$ was purified by $C_{18}$ cartridge and analyzed by HPLC. The average $D_3$ content in plasma of control chicks was 20 ng /$m\ell$. When 0.32 J/$\textrm{cm}^2$ of dose was treated, the highest amount of 43 ng /$m\ell$ was found among those of chicks experimented, corresponding to 2.15 times that of control. However, When more doses than 0.32 J/$\textrm{cm}^2$ were exposed to the skin, D$_3$ contents were decreased gradually. The similar to control level of $D_3$ was observed when 0.79 J/$\textrm{cm}^2$ was applied.

• Journal of Korea Multimedia Society
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• v.8 no.1
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• pp.88-100
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• 2005

In computer graphics, realistic skin rendering has been regarded as difficult tasks and remains as an important research subject. Translucent materials like skin have some complicated optical properties including subsurface scattering. In this paper, we proposes a skin shader based on subsurface scattering to render realistic skin and it has been implemented as a plug-in for Maya, 3D Package. The rendered image using this proposed skin shader appears more realistic than the rendered image using classical shading techniques. Furthermore, we could model sebum, epidermis, dermis using specular reflection, multiple scattering, single scattering respectively.

• Composites Research
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• v.20 no.3
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• pp.25-30
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• 2007

This paper describes the basic design and fabrication of smart skin antenna for phased array applications. The smart skin phased array antenna, of which radiation pattern can be electrically steerable without mechanical rotation, has to meet the both mechanical and electrical performance. The smart skin antenna is a honeycomb sandwich structure to enhance the mechanical performance such as strength, weight and so on. The example of smart skin antenna integrated with radome is designed with the resonant frequency of 5 GHz, circular polarization, 2 by 2 subarray, and a coaxial probe-fed excitation. In addition, the performance of raw microstrip patch antenna uncovered radome is investigate. The fabricated smart skin antenna shows a reasonable performance with gain of 12.2 dBi and frequency bandwidth of 6.4 %.

• Korean Journal of Poultry Science
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• v.20 no.2
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• pp.93-105
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• 1993

This study was carried out to determine the concentrations of previtamin D$_3$(PreD$_3$), lumisterol$_3$(L3), tachystero1$_3$(73), vitamin D$_3$(VD$_3$) and provitamin D$_3$(ProD$_3$) in leg skins of broiler chicks exposed to UVB lights (maximum intensity at 297 nm) with dose of 0.204 or 0.409 mJ/$\textrm{cm}^2$(30 or 60 min irradiation) . The broiler Hubbard line day old chicks(2 dose $\times$9 elapsed time $\times$4 replica＋10 control＝82) were fed VD-deficient diet for 31 days in a windowless subdued light room. The skin was collected at 0, 6, 12, 18, 30, 42, 66, 90 or 138 hr after UVB irradiation. The skin lipid was extracted by 9％ ethyl acetate/n-hexane, and the fraction of VD$_3$ and its analogues was purified by Sep-Pak silica cartridge. The straight phase HPLC was utilized to analyze ProD$_3$ and its products. The mole ％(absolute level expressed in ng/$\textrm{cm}^2$) of PreD$_3$ in leg skin (epidermis＋dermis) was 4.67％(44 ng/$\textrm{cm}^2$) or 3.97％(37 ng/$\textrm{cm}^2$) right after UVB irradiation by 0.204 or 0.409 mJ/$\textrm{cm}^2$(30 or 60 min) at 15 cm distance, respectively. It content in leg skin at 0 hr after exposure was 7.24％(12 ng/$\textrm{cm}^2$) or 0.92％(9 ng/$\textrm{cm}^2$), respectively. The increase in irradiation dose did not affect proportionally the If synthesis.73 concentration in leg skin was 0.58％(S ng/$\textrm{cm}^2$) or 0.57％(6 ng/$\textrm{cm}^2$), respectively 0 hr after irradiation. The VD$_3$ in leg skin of birds exposed to UVB light with dose of 0.204 or 0.409 mJ/$\textrm{cm}^2$ was 2.13％ (21 ng/$\textrm{cm}^2$) or 0.97％ (16ng/$\textrm{cm}^2$), respectively at 0 hr after exposure, 2.72％(26ng/$\textrm{cm}^2$) or 3.84％(37ng/$\textrm{cm}^2$), respectively at 6 hr, and 4.30％ ((33ng/$\textrm{cm}^2$) or 6.40％(76ng/$\textrm{cm}^2$), respectively at 12 hr. The peak concentration of VD$_3$ was presented at 18 or 30 hr when 0.204 or 0.409 mJ/$\textrm{cm}^2$) was treated, respectively. It was shown that 18~30 hr were necessary for the thermal conversion of PreD$_3$ into VD$_3$ in the leg skin of broiler chicks. The ProD$_3$ contents in leg skins of negative control, 0.204 mJ/$\textrm{cm}^2$ and 0.409 mJ/$\textrm{cm}^2$ treated birds were 966, 948 and 815 ng/$\textrm{cm}^2$, respectively at right before and after UVB exposure. It was estimated that 18 or 151 ng/$\textrm{cm}^2$ of ProD$_3$ was isomerized to PreD$_3$, L$_3$, T$_3$ and VD$_3$ when exposed to 0.204 or 0.409 mJ/$\textrm{cm}^2$, respective)y. Consequently it was shown that when double dose of UVB light was applied to irradiate the chick body, more but not double synthesis of VD$_3$ and its analogues was occured in leg skin of brolier chicks.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.37 no.1
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• pp.91-96
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• 2011

Deficiency of collagen regeneration, denaturalization of fibers, increased melanin synthesis and reactive oxygen species are important factors inducing deterioration of healthy skin function. They induce freckles and decrease in skin elasticity. Vitamin C, vitamin A and their derivatives have been used as cosmetic ingredients for improvement of these problems but they have various problems. We have been developing the various derivatives of these ingredients. In this study, we investigated whitening effect of 3-o-cetyl-L-ascorbic acid (VCCE), a new vitamin C derivative. The VCCE inhibited melanogenesis in a dose dependent manner(44 % at $20\;{\mu}g/mL $) and tyrosinase expression. For 8 weeks, we also investigated skin brightening effect of VCCE on pigmented spots in UV-irradiated human skin. In results, VCCE showed a statistically significant skin whitening effect by mechanical and visual evaluation. Taken together, our findings suggest that the VCCE has potential benefits as an active ingredient for whitening cosmetics.

• Biomolecules & Therapeutics
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• v.32 no.2
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• pp.224-230
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• 2024

Pinitol (3-O-Methyl-D-chiro-inositol) has been reported to possess insulin-like effects and is known as one of the anti-diabetic agents to improve muscle, liver, and endothelial cells. However, the beneficial effects of pinitol on the skin are not well known. Here, we investigated whether pinitol had effects on human dermal fibroblasts (HDFs), and human dermal equivalents (HDEs) irradiated with ultraviolet A (UVA), which causes various damages including photodamage in the skin. We observed that pinitol enhanced wound healing in UVA-damaged HDFs. We also found that pinitol significantly antagonized the UVA-induced up-regulation of matrix metalloproteinase 1 (MMP1), and the UVA-induced down-regulation of collagen type I and tissue inhibitor of metalloproteinases 1 (TIMP1) in HDEs. Electron microscopy analysis also revealed that pinitol remarkably increased the number of collagen fibrils with regular banding patterns in the dermis of UVA-irradiated human skin equivalents. Pinitol significantly reversed the UVA-induced phosphorylation levels of ERK and JNK but not p38, suggesting that this regulation may be the mechanism underlying the pinitol-mediated effects on UVA-irradiated HDEs. We also observed that pinitol specifically increased Smad3 phosphorylation, which is representative of the TGF-β signaling pathway for collagen synthesis. These data suggest that pinitol exerts several beneficial effects on UVA-induced damaged skin and can be used as a therapeutic agent to improve skin-related diseases.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.49 no.4
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• pp.323-330
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• 2023

The skin's barrier structure is formed through the differentiation process of epidermal keratinocytes. It consists of corneocytes that are composed of keratin proteins and lipids that fill the spaces between them. During this process, the lipids such as phospholipid that made up the membrane of the basal layer cells of the epidermis are decomposed and replaced with newly synthesized components like ceramide. In this study, the effect of ginsenoside Rg3 components on the packing of the intercellular lipid structure of the skin barrier and the barrier function was confirmed. To confirm this, Rg3 components were treated during the differentiation process of 3D epidermal cells. The FT-IR and TEWL analysis on 3D epidermis showed an enhancement in the orthorhombic lipid packing and an improvement in barrier function. Additionally, in HaCaT cells, an increase in the expression of EVOL1 and EVOL4, which synthesize long-chain lipids, was detected, along with a decrease in CERS6, which synthesizes short-chain ceramide, and an increase in ACER6, which decomposes ceramide using phytosphingosine. This suggests the possibility that Rg3 affects lipid synthesis during the epidermal differentiation process, resulting in changes in barrier function.