C/EBP-homologous protein (CHOP) is an important component of the endoplasmic reticulum (ER) stress response. We demonstrated the induction of ER stress in response to tunicamycin stimulation, as evidenced by increased expression of chaperone proteins Grp78, Grp94, and enhanced eukaryotic initiation factor 2 subunit 1 (eIF2α) phosphorylation in hepatocellular carcinoma cells. Tunicamycin-induced ER stress resulted in apoptosis and autophagy simultaneously. While inhibition of autophagy mediated by 3-methyladenine pretreatment or direct knockdown of LC3B promoted cell apoptosis, activation of autophagy with rapamycin decreased tunicamycin- induced apoptosis in HCC cells. Furthermore, CHOP was shown to be significantly upregulated upon treatment with tunicamycin in HCC cells. Specific knockdown of CHOP not only enhanced tunicamycin-induced autophagy, but also significantly attenuated ER stress-induced apoptosis in HCC cells. Accordingly, simultaneous inhibition of autophagy in HCC cells with CHOP-knockdown could partially resensitize ER stress-induced apoptosis. Taken together, our data indicate that CHOP may favor ER stress-induced apoptosis in HCC cells via inhibition of autophagy in vitro.

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A novel coronavirus (severe acute respiratory syndrome coronavirus 2, SARS-CoV-2) emerged in late 2019, causing an outbreak of pneumonia [coronavirus disease 2019 (COVID-19)] globally. Although the use of ready-made reaction mixes can enable more rapid PCR-based diagnosis of COVID-19, the need to transport and store these mixes at low temperatures presents challenges to already overburdened logistics networks. Methods: Here, we present an optimized freeze-drying procedure that allows SARS-CoV-2 PCR mixes to be transported and stored at ambient temperatures, without loss of activity. Additive-supplemented PCR mixes were freeze-dried. The residual moisture of the freeze-dried PCR mixes was measured by Karl-Fischer titration. Results: We found that the freeze-dried PCR mixes with~1.2% residual moisture are optimal for storage, transport, and reconstitution. The sensitivity, specificity, and repeatability of the freeze-dried reagents were similar to those of freshly prepared, wet reagents. The freeze-dried mixes retained activity at room temperature (18~25°C) for 28 days, and for 14 and 10 days when stored at 37°C and 56°C, respectively. Conclusion: The uptake of this approach will ease logistical challenges faced by transport networks and make more cold storage space available at diagnosis and hospital laboratories.

Congenital cytomegalovirus infection (cCMVi) is an important cause of sensorineural hearing loss in newborns. Detection of human cytomegalovirus (HCMV) DNA in urine has been used to screen for cCMVi in newborns. However, the matrix effect of urine on HCMV DNA detection is unclear. To evaluate the matrix effect of urine on HCMV DNA detection and optimize the sample process strategy to eliminate or minimize the impact of urine on HCMV DNA detection, DNA in spiked samples was extracted using different DNA extraction methods, and urine samples that could inhibit HCMV DNA detection were mixed to evaluate the inhibitory substances, inhibitory mechanism, and elimination of the inhibitory effect. The optimal urine sample process strategy was evaluated using 42 adult female urine samples and 42 newborn urine samples spiked with HCMV. Some urine samples were found to inhibit HCMV DNA detection due to DNA degradation. The addition of ≥5 mM EDTA to the urine before extraction eliminated the inhibitory effect of urine and did not affect the detection results of urine exhibiting no inhibition. Of the 42 adult female and 42 newborn urine samples, four and two samples, respectively, could inhibit HCMV DNA detection. However, the inhibitory effects of these six urine samples were eliminated after the addition of EDTA. The collective results indicate that the addition of EDTA can completely eliminate the impact of inhibitors present in urine on HCMV DNA extraction and improve the detection of HCMV in urine.

This study aims to investigate the cooling performance of various film cooling holes, including combined hole, cylinder hole, conical hole, and fan-shaped hole. For film cooling technology, a novel combined hole configuration is first proposed to improve the cooling protection for gas turbine engines. This combined hole consists of a central cylinder hole (an inclination angle of 35) and two additional side holes (a lateral diffusion angle of 30). Film holes for four-hole configurations have the same inlet diameter of 8 mm. The adiabatic film cooling effectiveness for each hole configuration is analyzed for varying blowing ratios (M ¼ 0.25, 0.5, 0.75, and 1.0). Results show that the best cooling performance for the conical and fan-shaped holes is obtained at the blowing ratio of 0.75. In addition, the combined hole configuration provides a more uniform cooling protection and a better cooling performance than the other hole configurations.

In view of the complex procedure of nucleic acid extraction, there exists a huge challenge for the widespread use of point-of-care diagnostics for nucleic acid testing. To achieve point-of-care applications in a more rapid and cost-efficient manner, we designed a snake pipe-shaped microfluidic chip so as to accomplish reagents-prestored, time-saving, operation-simple nucleic acid extraction. All reagents needed for this process, including lysis buffer, wash buffer, elution buffer, and so on, were preloaded in the snake pipe and securely isolated by membrane valves, without the need for using any specialized equipment. By an integrated chip and a powerful ultrasonic, this device could complete virus nucleic acid extraction from sophisticated serum samples in less than 1 min. We used hepatitis B virus (HBV) and human immunodeficiency virus (HIV) mixed with different sources of serum as samples to be extracted. The coefficient of variation of HBV and HIV extraction on-chip was 1.32% and 2.74%, respectively, and there were no significant differences between on-chip and commercial instrument extraction (P > 0.05, α = 0.05) in different dilution ratios, which showed that the extraction device we established had excellent stability and sensitivity.