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Many aptamers have been generated by systematic evolution of ligands by exponential enrichment (SELEX) to recognize spike proteins of the severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2&ek), some of which have been engineered into dimeric and trimeric versions for enhanced affinity for diagnostic applications. However, no studies have been conducted to compare the utilities of monomeric, dimeric and trimeric aptamers in diagnostic assays with real clinical samples to answer the question of what levels of affinity an aptamer must have for accurate clinical diagnostics. Herein, we carried out a comparative study with two monomeric aptamers MSA1 and MSA5, one dimeric aptamer and two homotrimeric aptamers constructed with MSA1 and MSA5, with affinity varying by 1000‐fold. Using a colorimetric sandwich assay to analyze 48 human saliva samples, we found that the trimeric aptamer assay (Kd≈10 pM) can identify the SARS‐CoV‐2 infection much more accurately than the dimeric aptamer assay (Kd≈100 pM) and monomeric aptamer assay (Kd≈10,000 pM). Based on the experimental data, we theoretically predict the levels of affinity an aptamer needs to possess to achieve 80–100 % sensitivity and 100 % specificity. The findings from this study highlight the need for deriving very high affinity aptamers to enable highly accurate detection of viral infection for future pandemics. [ABSTRACT FROM AUTHOR]

Background and purpose: Tumor necrosis factor-α (TNF-α) not only acts as proinflammatory cytokine conducing to wide spectrum of human diseases including inflammatory diseases, but also can induce tumor development. In the current study, we investigated the relationship between TNF-α gene polymorphisms and the occurrence and development of non-small cell lung cancer (NSCLC) in Han population of Yunnan Province. Methods: A total of 425 lung cancer patients with NSCLC and 438 healthy individuals were included from Han population of Yunnan Province. The genotypes of 5 polymorphism loci, rs1799964 (-1031T>C), rs1800630 (-863C>A), rs1799724 (-857C>T), rs1800629 (-308G>A) and rs361525 (-238G>A) of TNF-α gene were detected by TaqMan assay. The frequency distributions of allele, genotype and haplotype in NSCLC patients and healthy controls were analyzed. Results: There was no significant difference in the allele and genotype frequency among 5 single nucleotide polymorphism (SNP) sites in TNF-α gene promoter (P>0.05). And in stratification analysis, the frequency of rs1799724-T was significantly higher in the adenocarcinoma patients than in the controls (P=0.010, OR=1.56, 95% CI: 1.11-2.19), and the rs1799724-TT+TC carrier showed significantly higher susceptibility to adenocarcinoma in dominant model (P=0.007, OR=1.66, 95% CI: 1.146-2.417). The frequency of rs1800630-A was significantly higher in adenocarcinoma, squamous cell carcinoma and other histological types of carcinoma patients (P=0.013, OR=2.15, 95% CI: 1.16-3.96). The haplotype analysis indicated that the frequency of haplotype rs1799724T-rs1800629G was higher in the adenocarcinoma group than in the control group (P=0.048, OR=1.42, 95% CI: 1.00-2.01). Conclusion: The T allele and TT genotype of rs1799724 (C>T) in TNF-α gene promoter might be associated with the susceptibility to lung adenocarcinoma in Han population of Yunnan Province. And rs1800630 (C>T) -A might be a risk factor of other histological lung cancer in Han population of Yunnan Province.

The Shu Commandery was an important iron production center in southwest China during the Han Dynasty (202 BC‐AD 220). In 2007, archaeologists excavated a Han Dynasty smelting furnace (L1) at the Gushishan site and collected large amounts of smelting remains including slags, furnace bricks, and ores. Scientific analysis of the excavated slags was carried out to ascertain that the Gushishan site was a pig iron smelting site. No flux was used at the Gushishan site, and the site is dated no later than the Eastern Han period. No remains related to iron casting of the Han Dynasty was found at or near the iron smelting sites in southwest China, which indicates a separation between iron smelting and iron casting as characteristics of the industrial layout in this region. [ABSTRACT FROM AUTHOR]

Objective: To investigate the association between coronary heart disease (CHD) and the risk of perioperative ischemic stroke in patients undergoing noncardiac surgery. Methods: This retrospective study evaluated the incidence of ischemic stroke within 30 days after a noncardiac surgery. A cohort of 221,541 patients who underwent noncardiac surgery between January 2008 and August 2019 was segregated according to whether they were diagnosed with CHD. Primary, sensitivity, and subgroup logistic regression analyses were conducted to confirm that CHD is an independent risk factor for perioperative ischemic stroke. Propensity score matching analysis was used to account for the potential residual confounding effect of covariates. Results: Among the 221,541 included patients undergoing noncardiac surgery, 484 patients (0.22%) experienced perioperative ischemic stroke. The risk of perioperative ischemic stroke was higher in patients with CHD (0.7%) compared to patients without CHD (0.2%), and multivariate logistic regression analysis showed that CHD was associated with a significantly increased risk of perioperative ischemic stroke (odds ratio (OR), 3.7943; 95% confidence interval (CI) 2.865–4.934; p < 0.001). In a subset of patients selected by propensity score matching (PSM) in which all covariates between the two groups were well balanced, the association between CHD and increased risk of perioperative ischemic stroke remained significantly significant (OR 1.8150; 95% CI, 1.254–2.619; p = 0.001). In the subgroup analysis stratified by age, preoperative β‐blockers, and fibrinogen‐to‐albumin ratio (FAR), the association between CHD and perioperative ischemic stroke was stable (p for interaction >0.05). Subgroup analyses also showed that CHD was significantly increased the risk of perioperative ischemic stroke in the preoperative mean arterial pressure (MAP) ≥94.2 mmHg subgroups (p for interaction <0.001). Conclusion: CHD is significantly associated with an increased risk of perioperative ischemic stroke and is an independent risk factor for perioperative ischemic stroke after noncardiac surgery. Strict control of preoperative blood pressure may reduce the risk of perioperative ischemic stroke for patients with CHD undergoing noncardiac surgery. [ABSTRACT FROM AUTHOR]

High‐precision viral detection at point of need with clinical samples plays a pivotal role in the diagnosis of infectious diseases and the control of a global pandemic. However, the complexity of clinical samples that often contain very low viral concentrations makes it a huge challenge to develop simple diagnostic devices that do not require any sample processing and yet are capable of meeting performance metrics such as very high sensitivity and specificity. Herein we describe a new single‐pot and single‐step electrochemical method that uses real‐time kinetic profiling of the interaction between a high‐affinity aptamer and an antigen on a viral surface. This method generates many data points per sample, which when combined with machine learning, can deliver highly accurate test results in a short testing time. We demonstrate this concept using both SARS‐CoV‐2 and Influenza A viruses as model viruses with specifically engineered high‐affinity aptamers. Utilizing this technique to diagnose COVID‐19 with 37 real human saliva samples results in a sensitivity and specificity of both 100 % (27 true negatives and 10 true positives, with 0 false negative and 0 false positive), which showcases the superb diagnostic precision of this method. [ABSTRACT FROM AUTHOR]

Deep-shaft mining in roadway stress concentration, difficult control of the surrounding rock, and mining imbalance affect mining efficiency in coal mines. The mechanical parameters and crack development law of roadway surrounding rock were studied by laboratory experiments. The mechanical model was established by the method of theoretical analysis, the maximum empty roof distance was deduced, and two support schemes were designed. Through the numerical simulation method, the support scheme was compared and analyzed, the deformation rule of roadway surrounding rock, the optimization of roadway support parameters and the application of hysteresis technology are studied. The effect of different support schemes was verified by three-dimensional similar simulation experiments. The practical engineering verification showed that the construction time of each support circle was reduced by approximately 1 h, and the work was completed 60 days earlier. The research showed that the optimal support scheme was support scheme 1 (7 bolts with 800 mm × 1000 mm spacing between the roof, 10 bolts with 800 mm × 1000 mm spacing between the two sides, and 2 × 1 × 2 cables with 1600 mm × 2000 mm spacing between the roof). Support scheme 1 was applied to the engineering site to control the deformation of surrounding rock at 80 mm, and the deformation was less than the original support scheme. The construction was completed in advance under the hysteresis process, and the support efficiency and operation safety were improved. The results revealed the mechanism of surrounding rock control and proved the effectiveness of digging support synergy. This optimization plan serves as a reference for studying roadway support in rapid excavation and provides theoretical support for safe and efficient coal roadway mining. [ABSTRACT FROM AUTHOR]