No abstract

This study was designed to investigate the pro-inflammatory cytokines and their involvement in the cytotoxic potential of fluoride (F) in HeLa cells. HeLa cells were cultured with varying F concentrations (1-50 mg/L) for 48 h, and treatment effects were analyzed. The viability of HeLa cells was determined with a colorimetric method. The concentrations of IL-1β, IL-2, IL-6, and TNF-a in culture supernatant were measured through enzyme linked immunosorbent assay (ELISA). The mRNA expression levels of IL-1β, IL-2, IL-6 and TNF-a were subjected to transcript analysis and quantified through reverse transcription real-time PCR. Results showed that 10, 20 and 50 mg/L F significantly decreased the viability of HeLa cells incubated for 24 and 48 h. With their cytotoxic effect, the concentrations of IL-1β, IL-2, IL-6, and TNF-a decreased significantly in response to F, especially at 20 and 50 mg/L for 48 h. The mRNA expression levels of IL-1β, IL-2, IL-6, and TNF-a were downregulated at 50 mg/L F for 48 h. Therefore, F inhibited HeLa cell growth; as such, F could be used to alleviate the inhibition of pro-inflammatory cytokine expression.

A high-stability voltage regulator (VR) is proposed in this paper, which integrates transient enhancement and overcurrent protection (OCP). Taken into consideration the performance and area advantages of low-voltage devices, most control parts of proposed VR are supplied by the regulated output voltage, which forms self-power technique (SPT) with power supply rejection (PSR) boosting. Besides, the stability and transient response are enhanced by dynamic load technique (DLT). An embedded overcurrent feedback loop is also adopted to protect the presented VR from damage under overload situations. The proposed VR is implemented in a standard 350 nm BCD technology, whose results indicate the VR can steadily work with 5.5–30 V input voltage, 0–30 mA load range, and 0.1–3.3 μF output capacitor. A 2.98 μV/V line regulation and a 0.233 mV/mA load regulation are achieved with a 40 mA current limiting. The PSR is better than − 64 dB up to 10 MHz with a 0.1 μF output capacitor.

In this paper, a nano-watt resistorless subthreshold voltage reference with high-power supply rejection ratio (PSRR) is presented. A self-biased MOS voltage divider is proposed to provide bias current for whole voltage reference, which is a positive temperature coefficient (TC) current containing threshold voltage characteristics. By injecting the generated current into a transistor with a different threshold voltage, a delta threshold voltage with a greatly reduced negative TC is realized and temperature-compensated by a generated positive TC item at the same time. Therefore, a temperature-stable voltage reference is achieved in the proposed compacted method with low power consumption and high PSRR. Verification results with 65-nm CMOS technology demonstrate that the minimum supply voltage can be as low as 0.35 V with a 0.00182-mm2 active area. The generated reference voltage is 148 mV, with a TC of 28 ppm/°C for the − 30 to 80 °C temperature range. The line sensitivity is 1.8 mV/V, and the PSRR without any filtering capacitor at 100 Hz is 53 dB with a 2.28-nW power consumption.