The function of middle hepatitis B surface protein C-terminally truncated at amino acid position 167 (MHBst167) is not currently clear. This study aimed to screen and identify the proteins that interact with MHBst167 in hepatocytes using a yeast two-hybrid system, and to explore the effects of MHBst167 in the development of hepatocellular carcinoma and precancerous diseases of the liver. The MHBst167 gene was amplified by polymerase chain reaction (PCR) and cloned into a pGEM-T vector. The target region was sequenced and the constructed bait plasmid, pGBKT7-MHBst167, was transformed into AH109 yeast cells. The transformed AH109 cells were then mated with Y187 yeast cells containing the fetal liver cDNA library plasmid using a yeast two-hybrid system. The false positives were eliminated and the true positive clones were selected by PCR and sequencing analysis. The pGBKT7-MHBst167 bait plasmid was successfully constructed and 66 clones grew in the selective synthetic defined media lacking leucine, tryptophan, histidine and adenine. Fifty-two clones were identified following X-α-Gal selection and segregation analysis. Seven proteins were found to be expressed that could interact with MHBst167 in hepatocytes by the yeast two-hybrid system. These results have provided novel insights into the biological functions of MHBst167.

This paper introduces a 2.4 GHz down-conversion quadrature mixer which applied in the Wireless Sensor Network (WSN). The mixer uses a folded structure which is modified based on the conventional Gilbert mixer. It is designed in 0.18μm RF CMOS process with a low supply voltage of 1V. The post-simulation results show that the mixer achieves a conversion gain (CG) of 9.0dB, the input 1dB compression point (IP1dB) of-7.6dBm, the third-order input intercept point (IIP3) of 2.2dBm, and the single side-band (SSB) noise figure (NF) is 13.9dB. The mixer core consumes current about 1.2mA from a 1V power supply.

A fourth-order low-pass continuous-time filter for a WSN transmitter is presented. The active RC filter was chosen for the high linearity, designed by using the leapfrog topology imitates the passive filter. The operation amplifier (op-amp) adopted by the filter is feed-forward operation amplifier, which could get the GBW as large as possible under the low power consumption. The cut-off frequency deviation due to the process corner, aging and temperature deviation is adjusted by an automatic frequency tuning circuit. The filter in a 0.18μm RF CMOS technology consumes 1mW from a 1V power supply. The measured results of the chip show that the bandwidth is about 1.5MHz. The voltage gain of filter is about-4.5dB with the buffer, the ripple in the pass-band is lower than 0.5 dB, and the channel rejection ratio is larger than 30dB at 4MHz.

A low voltage, low power up-conversion mixer is presented here for 2.4GHz wireless sensor networks (WSN). It was based on a double-balanced Gilbert cell type. The current-reuse technique was used to reduce the power consumption and negative-resistance compensation technique was used to improve the conversion gain. The mixer was designed in 0.18μm RF CMOS technology, and was simulated with Cadence SpectreRF. The simulation results indicate that the conversion gain is 6.37dB, the noise figure is 15.36dB and the input 1dB compression point is-10.3dBm, while consuming 1mA current for operating voltage at 1V.