RESUMO
This paper proposes a wide dynamic range (DR) and high-resolution discrete-time (DT) 2-order 4-bit sigma-delta modulator with a novel dynamic-modulated scaling-down (DM-SD) technology for non-invasive electroencephalogram (EEG) acquisition. The DM-SD technology can expand the input dynamic range and suppress large input offsets at the same time. The modulator was designed with 180nm CMOS technology with an area of 0.49 mm2. We achieve a 118.1 dB SNDR when the input signal is 437.5 Hz and the signal bandwidth is 1500 Hz. Due to the proposed DM-SD technology, the DR is expanded to 126 dB. The power consumption of the whole modulator is 1.6 mW and a 177.8 dB Schreier figure-of-merit (FoMs) is realized.
Assuntos
Eletroencefalografia , Conversão Análogo-DigitalRESUMO
To observe and investigate the in vitro effect of ulipristal acetate (UPA) on human sperm parameters and function. The 20 patients with normal semen parameters and average age of (32.5±8.5) years old, who were treated in our hospital from January 2018 to August 2018, were selected as research objects. They were subjected to density gradient centrifugation, and then four groups were incubated for about an hour in a culture medium containing different concentrates of ulipristal acetate and the other two groups were set as blank control group and dimethylsulphoxide (DMSO) control group. Indicators including sperm motility, sperm hyperactivation and sperm concentration of free calcium ions of each group were tested. Under the ulipristal acetate concentration of 0.0.4 mol/L, the proportion of sperm damage was increased, the length of tail was increased, and the proportion of sperm hyperactivation was decreased, p<0.05. In addition, the acrosome reaction was inhibited, which significantly reduced the calcium concentration in the sperm, p<0.05. Ulipristal acetate can significantly inhibit acrosome reaction and hyperactivation of sperm in vitro, and can reduce the concentration of calcium ions in sperm, thus causing sperm damage.