• KSBB Journal
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• 제29권1호
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• pp.42-49
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• 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
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• 제9권2호
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• pp.500-502
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• 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
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• 제4권3호
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• pp.5-9
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• 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.

• 대한화장품학회지
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• 제39권1호
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• pp.39-46
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• 2013

칼슘, 마그네슘과 같은 양이온은 피부 장벽을 보호하는 기능이 있다고 알려져 있다. 본 연구의 목적은 칼슘, 마그네슘, 망간, 불소로 이루어진 미네랄워터의 피부 장벽 보호 기능을 확인하기 위한 것이다. 피부가 자외선에 노출되게 되면 밀착연접(tight junction, TJ)이 파괴되며, 밀착연접으로 이루어진 피부 장벽도 손상 받게된다. 미네랄워터가 자외선에 의해 손상된 피부의 장벽기능을 보호할 수 있는지 평가하기 위해 인공피부 모델을 이용한 실험을 진행하였다. 인공피부에 자외선을 조사하고 미네랄워터를 처리하면 피부 장벽 손상을 막아준다. TJ permeability assay를 통하여 자외선 처리 시 손상된 밀착연접 장벽이 미네랄워터 처리에 의해 유지되는 것을 확인하였다. 각질형성세포를 이용한 실험에서 미네랄워터가 밀착연접 구조를 유지시켜 주고, 자외선에 의해 감소된 occludin 단백질의 생성량이 회복되는 것을 확인하였다. 따라서 본 연구를 통해 미네랄워터는 자외선에 의한 피부 장벽 파괴를 막아주는 효과가 있음을 확인할 수 있었다.

• The Korean Journal of Physiology and Pharmacology
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• 제18권3호
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• pp.249-254
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• 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.

• 대한화장품학회지
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• 제42권4호
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• pp.343-349
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• 2016

제주용암해수는 미네랄과 영양염류가 풍부한 물로 제주만이 보유한 지하수자원이다. 본 연구의 목적은 제주용암해수의 피부 보습효과를 확인하기 위한 것이다. 피부의 건조함을 막고 수분을 유지하기 위해서는 표피층의 장벽기능이 정상적으로 기능하고, 표피층 내 수분의 유지와 이동이 원활히 이루어져야 한다. 제주용암해수를 각질형성세포에 처리한 결과 표피층의 분화과정과 natural moisturizing factor (NMF) 생성과정에 관여하는 유전자인 필라그린과 caspase-14 유전자의 발현양이 증가되는 것을 확인할 수 있었다. 또한 막관통 단백질로 수분의 이동을 조절하는 aquaporin 3 (AQP3) 유전자 발현양과 단백질 발현양도 제주용암해수 처리에 의해 증가하였다. 인공피부를 이용한 실험에서 제주용암해수를 배지에 처리하고 배양한 결과 hyaluronic acid (HA)의 수용체인 CD44의 발현양이 증가하였다. 본 연구를 통해 제주용암해수는 피부 보습과 관련된 인자들의 발현양을 증가시켜 피부의 보습기능에 도움을 주는 것으로 사료되었다.

• Steel and Composite Structures
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• 제7권1호
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• pp.35-52
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• 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.

• 대한전자공학회논문지SD
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• 제40권8호
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• pp.555-559
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• 2003

본 논문에서는 CMOS 소자의 RF 동작을 정확히 예측하기 위해 Si 표면에서의 메탈 라인 사이의 커패시턴스 효과와 표피효과 및 근접효과를 포함한 RF IC 설계를 위한 새로운 CMOS RF 모델을 처음으로 제시하였다. Si 표면에서의 메탈 라인 사이의 커패시턴스는 레이아웃에 기초하여 모델링하였으며, 표피효과는 메탈 라인의 등가회로에 병렬회로를 부가하여 사다리꼴 등가회로로 구현하였다. 근접효과는 사다리꼴 등가회로에서 교차 결합된 인덕턴스 사이의 상호 인덕턴스를 부가함으로써 모델링하였다. 제안된 RF 모델은 BSIM 3v3에 비해 측정 데이터와 잘 일치하였으며, GHz 영역에서 소자 동작의 주파수 종속성을 잘 보여주었다.

• JSTS:Journal of Semiconductor Technology and Science
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• 제10권4호
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• pp.300-308
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• 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.

• 전기전자학회논문지
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• 제24권3호
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• pp.713-718
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• 2020

피부 활성점(경혈) 측정 방법은 편리성, 저비용 및 비 침습으로 측정하기 때문에 많은 생체정보를 얻기 위한 기술이다. 본 연구에서는 피부 아래에 활성점을 측정할 수 있는 장점이 있는 3전극 측정방법을 사용되었다. 임피던스측정방법은 측정실험 결과와 관련성이 있는 등가전기회로를 통해서 증명되었다. 활성점의 특성주파수는 주변 피부보다 15-30Hz 높고, 리액턴스는 35-77kΩ 더 작게 측정되었다. 이 기술은 비침습 측정 시스템을 이용해서 활성점과 주변피부의 리액턴스와 특성주파수를 정확하고 객관적으로 분석되었다.