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Although retinoic acid (RA) is well known to inhibit the differentiation of 3T3-L1 cells into adipocytes both in vivo and in vitro, its molecular mechanism is not fully understood. In this report, we investigate the inhibitory mechanism of adipocyte differentiation by RA in 3T3-L1 cells. Because both RA and Wnt are known to inhibit adipogenesis at a common step involving the inhibition of PPAR-γ expression, we focused on the crosstalk between these two signaling pathways. We found that RA treatment resulted in a dramatic inhibition of adipogenesis, especially at an early phase of differentiation, and led to increased β-catenin protein expression. Moreover, RA enhances the transcriptional activity of β-catenin as well as Wnt gene expression during adipogenesis. Taken together, the present study demonstrated that Wnt/β-catenin signaling may be associated with the RA-induced suppression of adipogenesis and may cooperatively inhibit adipocyte differentiation.

A methodology for modeling and simulating the electro-thermal behavior of an enclosed electronic package is presented and validated. The electro-thermal model is constructed using system dynamics. The system model, in which the electrical and the thermal domain are combined, is presented. The developed model describes the dynamic thermal behavior system that was an electronic device in the test enclosure. An effective way to identify the thermal parameters of the system, especially the thermal contact resistance, is suggested. In detail, the new method for thermal resistance identification is based on the temperature difference behavior between the component and the air temperature inside the enclosure. Based on the proposed model, either the variation of the heat source or the ambient temperature can be estimated. Simulated results were in good agreement with the measured temperature in the transient state accompanying with the variation of the environment.

A piezoresistive silicon pressure sensor with bipolar on-chip signal conditioning circuits permits offset voltage, full scale span and temperature coefficient of offset voltage and full scale span to be calibrated from a trimming ion-implanted resistors. The ion-implanted resistors with temperature coefficient of 1700 ppm/°C or 4700 ppm/°C were fabricated by the same process as that used for the base and piezoresistors. The fabricated sensor exhibits a sensitivity of 40.5 mV/kPa and temperature coefficient of 46 ppm/°C at the temperature range of −10 to 70°C.

A new micro catalytic gas sensor for detecting inflammable gases was fabricated on a Si wafer by thin film deposition and Si anisotropic etching. The size of the fabricated sensor was 3.25×2.20 mm 2 . The sensor was designed to consist of a catalyst with high surface area and a heater with high temperature coefficient of resistance (TCR) in order to acquire high sensitivity to gases of interest. The TCR of the sensor was found to be 3844 ppm °C −1 . Sensitivities to methane and butane gases were 2.2 mV 1000 ppm −1 and 8.9 mV 1000 ppm −1 , respectively. The optimum applied Wheatstone bridge power was varied in the range from 350 to 400 mW, being much smaller than those of commercial pellistors. It was also found that sensitivities to methane and butane gas were decreased by increasing humidity.

Fourier-transform infrared (FT-IR) spectroscopy, a non-destructive, label-free, and high sensitive and specific analytical method is a vibrational technique that gives information on the chemical composition of a sample of biological specimens. It is also a powerful approach to detect changes in the protein composition and structure of intact living cells. To determine a cellular function or change of biological materials (cells, tissues, microorganisms, etc.), we have studied the amide I band of protein by using both FT-IR spectra based on attenuated total reflection (ATR) and their second derivative spectra. we have performed the breast cancer cells and the pathogenic microorganisms exposed to anticancer and antibiotic drugs, respectively. Based on these studies, we found that the potential to use this technique for the detection and quantification of the protein secondary structure components of biological specimens under drug application