Hypoxia induced apoptosis of rat gastric mucosal cells by activating autophagy through HIF-1α/TERT/mTORC1 pathway

The pathogenesis of high altitude-related gastric mucosal injury remains poorly understood,this study aimed to investigate the role of autophagy in hypoxia-induced apoptosis of rat gastric mucosal cells.Rats were randomized into four groups which were maintained at an altitude of 400 m(P)or received no treatment(H),autophagy inducer rapamycin(H+AI)or autophagy inhibitor 3-MA(H+AB)at an altitude of 4,300 m for 1,7,14 and 21 days,respectively,and the morphology,ultrastructure,autophagy,and apoptosis of gastric mucosal tissues were examined.Gastric mucosal epithelial cells CC-R039 were cultured under conditions of normoxia,2%O2(hypoxia),or 2%O2+anti-mTORC1 for 0,24,48,and 72 h,respectively,and the autophagy and apoptosis were analyzed.CC-R039 cells were transfected with siHIF-1α,siTERT,or siRNA and the autophagy was examined.The results showed that the exposure to hypoxia increased the autophagy and apoptosis of gastric mucosal cells in rats,and apoptosis was aggravated by rapamycin treatment but alleviated by 3-MA treatment.Increased duration of hypoxia from 0 to 72 h could increase the autophagy and apoptosis but decrease the proliferation of gastric mucosal cells.Inhibition of mTORC1 with rapamycin led to further increase in apoptosis and even substantial cell death,and inhibition of HIF-1αand TERT increased mTORC1 expression and reduced autophagy.Moreover,the inhibition of HIF-1αreduced TERT expression.In conclusion,hypoxia could induce apoptosis of rat gastric mucosal cells by activating autophagy through HIF-1α/TERT/mTORC1 pathway.

An 8 bit 1 MS/s SAR ADC with 7.72-ENOB

This paper presents a low power 8-bit 1 MS/s SAR ADC with 7.72-bit ENOB. Without an op-amp, an improved segmented capacitor DAC is proposed to reduce the capacitance and the chip area. A dynamic latch comparator with output offset voltage storage technology is used to improve the precision. Adding an extra positive feedback in the latch is to increase the speed. What is more, two pairs of CMOS switches are utilized to eliminate the kickback noise introduced by the latch. The proposed SAR ADC was fabricated in SMIC 0.18μm CMOS technology. The measured results show that this design achieves an SFDR of 61.8 dB and an ENOB of 7.72 bits, and it consumes 67.5μW with the FOM of 312 fJ/conversion-step at 1 MS/s sample under 1.8 V power supply.

Isolation and Growth Characteristics of SARS-CoV-2 in Vero Cell

Dear Editors,The coronavirus disease 2019(COVID-19),caused by SARS-CoV-2,broke out in early December 2019 has escalated into a global pandemic(Lai et al.2020).Till the May 20 th 2020,more than 4,700,000 people were infected and the number is still increasing especially in Europe,North America and Asia(https://covid19.who.int/).