• KSBB Journal
• /
• v.29 no.1
• /
• pp.42-49
• /
• 2014

The aim of this study was to develop a composite human skin equivalent for wound healing. Collagen type1 and acellular dermal matrix powder were utilized as the scaffold with dermal fibroblasts and keratinocytes for the development of a composite human skin equivalent. Fibroblast maintained the volume of composite skin equivalent and also induced keratinocytes to attach and proliferate on the surface of composite skin equivalent. The composite human skin equivalent had a structure and curvature similar to those of real skin. Balb-C nu/nu mice were used for the evaluation of full-thickness wound healing effect of the composite human skin equivalent. Graft of composite skin equivalent on full-thickness wound promoted re-epithelialization and granulation tissue formation at 9 days. Given the average wound-healing time (14 days), the wound in the developed composite skin equivalent healed quickly. The overall results indicated that this three-dimensional composite human skin equivalent can be used to effectively enhance wound healing.

• Journal of Photoscience
• /
• v.9 no.2
• /
• pp.500-502
• /
• 2002

In vitro and in vivo studies have reported the induction of matrix metaloproteinase (MMP)-1 in the fibroblasts by ultraviolet (UV) A irradiation. We constructed the skin equivalent model using HaCaT cells as keratinocytes and human neonatal dennal fibroblasts as fibroblasts in the present study. The induction of MMP-l in the fibroblasts was confirmed immunohistochemically 6 hours after UVA irradiation using this model. This model was simply composed of human keratinocytes and fibroblasts. To our knowledge, there have been a few papers concerning the skin equivalent model in the field of photobiology. The effect of UVA exposure to fibroblasts through keratinocytes was examined using this model. The cross-talk can be examined between keratinocytes and fibroblasts. This model can be a useful tool in the field of photobiology.

• Transactions on Electrical and Electronic Materials
• /
• v.4 no.3
• /
• pp.5-9
• /
• 2003

In this paper, a layout-based CMOS RF model for RFIC's including the capacitance effect, the skin effect, and the proximity effect between metal lines on the Si surface is proposed for the first time for accurately predicting the RF behavior of CMOS devices. With these RF effects, the RF equivalent circuit model based on the layout of the multi-finger gate transistor is presented. The capacitances between metal lines on the Si surface are modeled with the layout. And the skin effect is modeled to the equivalent ladder circuit of metal line. The proximity effect is modeled by adding the mutual inductance between cross-coupled inductances in the ladder circuit representation. Compared to the BSIM 3v3 and other models, the proposed RF model shows better agreements with the measured data and shows well the frequency dependent behavior of devices in GHz ranges.

• Journal of the Society of Cosmetic Scientists of Korea
• /
• v.39 no.1
• /
• pp.39-46
• /
• 2013

Bicationic minerals such as calcium and magnesium are known to protect the skin barrier. The principal objective of this study was to evaluate the skin barrier protective effects of mineral water, which is composed of calcium, magnesium, manganese, and fluorine. UVB irradiation induces a destruction of tight junction (TJ) components. The TJ permeability barrier was also disrupted by UVB irradiation. We employed a skin equivalent model to assess the efficacy of mineral water in this regard. Mineral water maintained the structure of the skin equivalents following UVB irradiation. The results of the TJ permeability assay showed that mineral water helped to maintain the TJ permeability barrier after UVB irradiation in skin equivalent model. Mineral water supported the structure of TJ components and restored the occludin protein level in differentiated normal human keratinocytes after UVB irradiation. In conclusion, we found out the protective effect of mineral water against UVB irradiation.

• The Korean Journal of Physiology and Pharmacology
• /
• v.18 no.3
• /
• pp.249-254
• /
• 2014

The purpose of this study is to characterize the effects of KHG26792 (3-(naphthalen-2-yl(propoxy)methyl)azetidine hydrochloride), a potential skin whitening agent, on melanin synthesis and identify the underlying mechanism of action. Our data showed that KHG26792 significantly reduced melanin synthesis in a dose-dependent manner. Additionally, KHG26792 downregulated microphthalmia-associated transcription factor (MITF) and tyrosinase, the rate-limiting enzyme in melanogenesis, although tyrosinase was not inhibited directly. KHG26792 activated extracellular signal-regulated kinase (ERK), whereas an ERK pathway inhibitor, PD98059, rescued KHG26792-induced hypopigmentation. These results suggest that KHG26792 decreases melanin production via ERK activation. Moreover, the hypopigmentary effects of KHG26792 were confirmed in a pigmented skin equivalent model using Cervi cornus Colla (deer antler glue), in which the color of the pigmented artificial skin became lighter after treatment with KHG26792. In summary, our findings suggest that KHG26792 is a novel skin whitening agent.

• Journal of the Society of Cosmetic Scientists of Korea
• /
• v.42 no.4
• /
• pp.343-349
• /
• 2016

Many minerals and nutrient salts are abundant in Jeju lava sea water. The objective of this study was to evaluate the skin hydration effects of Jeju lava sea water. The skin barrier serves as a protective barrier that prevents the loss of moisture. The water holding capacity and water transport of the epidermis have been proposed to be important determinants of skin hydration. Jeju lava sea water increased the mRNA expression of filaggrin and caspase-14 which is related to natural moisturizing factor (NMF) formation. Aquaporins 3 (AQP3) are proteins that facilitate the transport of water across cell membranes. Jeju lava sea water increased the mRNA expression and protein expression of AQP3. We employed a skin equivalent model to assess the efficacy of Jeju lava sea water. In a skin equivalent model, Jeju lava sea water increased the CD44 (hyaluronic acid receptor) which is related to skin hydration. From these results, we found out Jeju lava sea water maybe help to skin hydration.

• Steel and Composite Structures
• /
• v.7 no.1
• /
• pp.35-52
• /
• 2007

The cold formed light-gauge profiled steel sheeting can offer considerable shear resistance acting in the steel building frame. This paper conducted the full-scale test on the shear behavior of stressed skin diaphragm using profiled sheeting connected by the self-tapping screws. A three-dimensional finite element model that simulates the stressed skin diaphragm was developed. The sheet was modeled using thin element model while the supporting members were simulated using beam elements. Fasteners were represented in the numerical model as equivalent springs. A joint test program was conducted to characterize the properties of these springs and results were reported in this study. Finite element model of the full-scale test was analyzed by use of the ANSYS package, considering nonlinearity caused by the large deflection and slip of fasteners. The experimental data was compared with the results acquired by the EUR formulas and finite element analysis.

• Journal of the Institute of Electronics Engineers of Korea SD
• /
• v.40 no.8
• /
• pp.555-559
• /
• 2003

In this paper, a new CMOS RF model for RF IC design including the capacitance effect, the skin effect, and the proximity effect between metal lines on the Si surface is proposed for tile first time for accurately predicting the RF behavior of CMOS devices. The capacitances between metal lines on the Si surface are modeled with the layout. And the skin effect is modeled with a parallel branch added in equivalent circuit of metal line. The proximity effect is modeled by adding the mutual inductance between cross-coupled inductances in the ladder circuit representation. Compared to the BSIM 3v3. the proposed RF model shows good agreements with the measured data and shows well the frequency dependent behavior of devices in GHz ranges.

• JSTS:Journal of Semiconductor Technology and Science
• /
• v.10 no.4
• /
• pp.300-308
• /
• 2010

This paper describes the development of a low-power electrocardiogram (ECG) touch sensor intended for the use with two dry metal electrodes. An equivalent ECG extraction circuit model encountered in a ground-free two-electrode configuration is investigated for an optimal sensor read-out circuit design criteria. From the equivalent circuit model, (1) maximum sensor resolution is derived based on the electrode's background thermal noise, which originates from high electrode-skin contact impedance, together with the input referred noise of instrumentation amplifier (IA), (2) 60 Hz electrostatic coupling from mains and motion artifact are also considered to determine minimum requirement of common mode rejection ratio (CMRR) and input impedance of IA. A dedicated ECG read-out front end incorporating chopping scheme is introduced to provide an input referred circuit noise of 1.3 ${\mu}V_{rms}$ over 0.5 Hz ~ 200 Hz, CMRR of IA > 100 dB, sensor resolution of 7 bits, and dissipating only 36 ${\mu}W$. Together with 8 bits synchronous successive approximation register (SAR) ADC, the sensor IC chip is implemented in 0.18 ${\mu}m$ CMOS technology and integrated on a 5 cm $\times$ 8 cm PCB with two copper patterned electrodes. With the help of proposed touch sensor, ECG signal containing QRS complex and P, T waves are successfully extracted by simply touching the electrodes with two thumbs.

• Journal of IKEEE
• /
• v.24 no.3
• /
• pp.713-718
• /
• 2020

The method of measuring skin active points is a technique for obtaining a lot of biometric information because it is measured with convenience, low cost and non-invasive methods. In this paper, we used in a three electrode measure method that has the advantage of measuring the impedance of the APs under the skin. The impedance measuring method is well illustrated by a simple model of an equivalent electrical circuit that correlates well with experimental results. The characteristic frequencies of APs are about 15-30HZ higher than that of surrounding skin and the values of measured reactance are about 35-77KΩ smaller. This technology analyzed accurately and objectively the reactance and characteristic frequency of APs and the surrounding skin using a non-invasive measuring system.