[Epidemiological characteristics of two local COVID-19 outbreaks caused by 2019-nCoV Omicron variant in Guangzhou, China]

Objective: To understand the epidemiological characteristics of two local COVID-19 outbreaks caused by 2019-nCoV Omicron variant in Guangzhou, such as incubation period, serial interval, basic reproductive number (R₀) and the influence of gathering places on R₀, and provide evidence for the prevention and control of Omicron variant infection. Methods: The data of daily confirmed cases of Omicron variant infection from April 8 to May 8, 2022 in two COVID-19 outbreaks in Guangzhou were collected for model fitting. Weibull, Gamma and lognormal distribution were used to estimate incubation period and serial interval. Exponential growth method and the maximum likelihood estimation were used to estimate R₀. Results: The median of incubation period was 2.94 (95%CI: 2.52-3.38) days and median of serial interval was 3.32 (95%CI: 2.89-3.81) days. The estimated R₀ in small-size place was 4.40 (95%CI: 3.95-4.85), while the estimated R₀ at airport was 11.35 (95%CI: 11.02-11.67). Conclusion: The incubation period of Omicron variant in two local COVID-19 outbreaks in Guangzhou is significantly shorter than that of delta variant. The higher the gathering degree in a place, the larger the R₀. Due to its rapid transmission, COVID-19 epidemic is prone to occur. Therefore, the COVID-19 prevention and control strategy should be dynamically adjusted in time.

Oxidized low-density lipoprotein stimulates CD206 positive macrophages upregulating CD44 and CD133 expression in colorectal cancer with high-fat diet

BACKGROUND

Oxidized low-density lipoprotein (ox-LDL), which is abnormally increased in the serum of colorectal cancer (CRC) patients consuming a high-fat diet (HFD), may be one of the risk factors for the development of CRC. Ox-LDL exerts a regulatory effect on macrophages and may influence CRC through the tumor microenvironment. The role of ox-LDL in CRC remains unclear.

AIM

To investigate the role of ox-LDL through macrophages in HFD associated CRC.

METHODS

The expression of ox-LDL and CD206 was detected in colorectal tissues of CRC patients with hyperlipidemia and HFD-fed mice by immunofluorescence. We stimulated the macrophages with 20 μg/mL ox-LDL and assessed the expression levels of CD206 and the cytokines by cell fluorescence and quantitative polymerase chain reaction. We further knocked down LOX-1, the surface receptor of ox-LDL, to confirm the function of ox-LDL in macrophages. Then, LoVo cells were co-cultured with the stimulated macrophages to analyze the CD44 and CD133 expression by western blot.

RESULTS

The expression of ox-LDL and the CD206 was significantly increased in the stroma of colorectal tissues of CRC patients with hyperlipidemia, and also upregulated in the HFD-fed mice. Moreover, an increased level of CD206 and decreased level of inducible nitric oxide synthase were observed in macrophages after ox-LDL continuous stimulation. Such effects were inhibited when the surface receptor LOX-1 was knocked down in macrophages. Ox-LDL could induce CD206+ macrophages, which resulted in high expression of CD44 and CD133 in co-cultured LoVo cells.

CONCLUSION

Ox-LDL stimulates CD206+ macrophages to upregulate CD44 and CD133 expression in HFD related CRC.

[Pepsin and bile acids detection in saliva for the diagnosis of gastroesophageal reflux disease]

Objective: To identify the value of the detection of pepsin and bile acids in saliva for the diagnosis of gastroesophageal reflux disease(GERD). Methods: From January 2018 to June 2019, 104 GERD patients and 43 healthy people in Guangdong Provincial People's Hospital were recruited. The 104 patients of GERD group were divided into four sub-groups, including esophageal symptoms GERD group, extraesophageal symptoms GERD group, anxiety or depression group, non-anxiety and non-depression group. Saliva was collected on waking in morning and 2 h after finishing lunch. The concentration of the total pepsin(TPP) and total bile acids(TBA) from saliva was detected by ELISA method. Receiver operating characteristics analysis was used to identify the sensitivity and specificity of the saliva pepsin and bile acids detection. Results: The concentration of TPP in morning waking samples and postprandial samples in the GERD group was 27.1(9.7,50.3) μg/L and 32.4(14.0,58.7) μg/L, the concentration of TBA in postprandial samples was (18.4±2.3)μmol/L, and these levels were significantly higher than that of the control group [7.0(5.1, 9.1) μg/L, 7.4(5.2, 9.4) μg/L, (12.6±5.0)μmol/L](P<0.01). The concentration of TBA in morning waking samples had no significant difference between these two groups(P>0.05). The concentration of TPP and TBA had no significant difference among the four GERD sub-groups(P>0.05).Pepsin in postprandial saliva samples had moderate diagnostic value for GERD, when the saliva pepsin concentration in postprandial samples was higher than 41.33 μg/L, it had a sensitivity of 82.8% and a specificity of 73.3%. The bile acids in saliva had no significant diagnostic value for GERD. Conclusions: Pepsin detection in saliva has a high level of sensitivity and specificity for diagnosing GERD. However, bile acids in saliva has no significant diagnostic value for GERD.

Low-Voltage Metal-Oxide Thin Film Transistors Using P-Type Tin-Oxide Semiconductors

In this paper, the effect of channel annealing and oxygen flow rate in P-type tin-monoxide (SnO) thin film transistor (TFT) was investigated to reach the process compatibility with n-type oxide-based TFT. The optimized P-type SnO TFT with a small threshold voltage of -0.1 V, a high field-effect mobility of 4 cm² V^-1 s^-1 and an on/off current ratio of >10² was proposed. From the experimental results, the 150 °C channel annealing revealed a metallic behavior but a semiconductor-like property at a higher 200 °C that was favorable for transistor rectification. Besides, the higher oxygen flow rate was also helpful for improving device mobility and driving current, but shows a slight increase in off-state leakage, which is unavoidable due to the increase of grain in SnO channel.

CD8+CD28+/CD8+CD28- T cell equilibrium can predict the active stage for patients with inflammatory bowel disease

BACKGROUND/AIM

The balance of blood CD8⁺CD28⁺/CD8⁺CD28^- T cells has been verified to be vital for patients with ulcerative colitis (UC), but their role in inflammatory bowel disease (IBD) remains unknown. This investigation aimed to evaluate the efficiency of the balance in predicting the active stage in IBD patients.

METHODS

Fifty-three IBD subjects, including 31 UC and 22 Crohn's disease (CD) patients, were enrolled, and their peripheral blood CD8⁺CD28⁺ and CD8⁺CD28^- T cell levels were tested using flow cytometry. The risk factors related to prognosis were compared between UC and CD patients. A 1-year follow-up was performed for all the IBD patients, and the CD8⁺ T cells and their ratio were compared at the 3rd, 6th, 9th, and 12th months during follow-up. The sensitivity and specificity of the CD8⁺ T cell level and balance were analyzed through receiver operator characteristic (ROC) curves. The cumulative remission lasting rates (CRLRs) under the different factors were analyzed using the Kaplan-Meier method.

RESULTS

Higher prescription rates of immunosuppressants, steroids, probiotics, and biological agents (BAs) were found in CD subjects in comparison to UC subjects (P=0.005, 0.024, 0.034, and 0.001), as was a higher active rate during follow-up (95.5% of CD patients vs 67.7% of UC patients, P=0.035). The CD8⁺CD28⁺ T cell level and the CD8⁺CD28⁺/CD8⁺CD28^- T cell ratio were significantly higher in UC patients than in CD patients, but the reverse was true for CD8⁺CD28^- T cells during follow-up at the 9th and 12th month (all P<0.05). The diagnostic models of the initial CD8⁺CD28⁺ and CD8⁺CD28^- T cell numbers and the CD8⁺CD28⁺/CD8⁺CD28^- T cell ratio in predicting the active stage were found to be significant, with areas under the curves (AUCs) of 0.883, 0.098, and 0.913 for UC subjects (with 95% CI: 0.709-0.940, 0.009-0.188, and 0.842-1.003; P=0.001, 0.00, and 0.000) and 0.812, 0.078, and 0.898 for CD subjects (with 95% CI: 0.683-0.957, 0.003-0.158, and 0.837-0.998; P=0.003, 0.00, and 0.000). The cut-off values showed that when the ratios were 1.30 for UC and 1.22 for CD patients, the best sensitivity and specificity were observed, with 91.6% and 89.0% for UC and 88.5% and 85.1% for CD, respectively. The CRLRs were significantly higher in female, non-BA-treated, non-surgical IBD subjects when compared to male, BA-treated, surgical subjects (P=0.031, 0.000, and 0.000). The number of CD8⁺CD28⁺ and CD8⁺CD28^- T cells and the CD8⁺CD28⁺/CD8⁺CD28^- T cell ratio were correlated with BA treatment and surgery (all P<0.05).

CONCLUSION

The CD8⁺CD28⁺/CD8⁺CD28^- T cell balance, expected to be a novel immunologic marker, presented a satisfactory efficiency with high sensitivity and specificity in predicting the active stage in UC and CD patients, and the balance was closely related to the use of BAs and surgery.

The Role of Oxygen Vacancies on Switching Characteristics of TiO(x) Resistive Memories

Using oxygen vacancy rich (VO-rich) TiO(x) dielectric with high work function Ni electrode, large resistance window of > 10x and narrow current distribution were realized in the Ni/VO-rich TiO(x)/TaN resistive random access memory (RRAM) device. It can be ascribed to the formation and rupture of conducting filaments by the percolation of VOs and Ti interstitials. Moreover, the effects of annealing treatment and top electrode on resistive switching properties were investigated. The device with VO-deficient TiO(x) after annealing reduces the defects and exhibits small window and low switching currents. The device with low work function Ti top electrode provides low barrier to increase reset currents and the randomly distributed filamentary paths forms near the Ti causes wide current distribution.

[Long-term results of an operation alone and postoperative adjuvant chemotherapy in advanced gastric cancer--report of 265 patients]

During the period from June 1973 to December 1978, 338 patients with advanced gastric cancer were treated in our hospital. By retrospective grouping, 142 out of 265 patients with tumor resected received postoperative adjuvant chemotherapy (MMC + 5FU + Ara-C), 123 operated alone were taken for comparison. These two groups were similar in: age, sex, location of tumor, mode of resection, histological type, clinical stage and follow-up rate. The results indicated that the 1, 3 and 5 year survival rates of the combined group were much higher than those of the operation only group. Further analysis showed that the supplementary chemotherapy was particularly valid in stages III and IV. In stage III patients, the 5 year survival rate was increased by 27.8%. In stage IV patients, the 3 and 5 year survival rates of the combined group were 16.3% and 9.8% but none survived over 3 years in the operation only group. The authors believe that postoperative adjuvant chemotherapy plays an important role in controlling the micrometastatic and residual cancer foci.