Asymptotic solutions are developed for miscible displacements at Stokes flow conditions between parallel plates or in a cylindrical capillary, at large values of the geometric aspect ratio. The single integro-differential equation obtained is solved numerically for different values of the Péclet number and the viscosity ratio. At large values of the latter, the solution consists of a symmetric finger propagating in the middle of the gap or the capillary. Constraints on conventional convection-dispersion-equation approach for studying miscible instabilities in planar Hele–Shaw cells are obtained. The asymptotic formalism is next used to derive—in the limit of zero diffusion— a hyperbolic equation for the cross-sectionally averaged concentration, the solution of which is obtained by analytical means. This solution is valid as long as sharp shock fronts do not form. The results are compared with recent numerical simulations of the full problem and experiments of miscible displacement in a narrow capillary.

Context: The use of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) serological tests detect antibodies in the host, contributing to the identification of individuals who have been exposed to Coronavirus Disease 2019 (COVID-19). Objective: To critically evaluate two commercially available SARS-CoV-2 serology tests. Design: A total of 333 unique, non-duplicated serum samples obtained from COVID-19 patients (n=170) and negative controls (n=163) obtained pre-December 2019 were used in the study. Samples were tested on the Roche E411 and Abbott Architect i4000SR platforms and results were correlated to reverse transcription polymerase chain reaction (PCR) results and clinical symptoms. Results: There was a strong level of agreement in the qualitative results between both assays with a Cohen's kappa value of 0.840, P<.001. The specificity for both Roche and Abbott were excellent at 100%. Roche exhibited marginally better performance in the ≥21 days group with a sensitivity of 90.6% (95% CI 75.8–96.8%) versus Abbott's sensitivity 84.4% (95% CI 68.3 – 93.1%) as well as the 14–20 days group with a sensitivity of 85.7% (95% CI 65.4 – 95.0%) versus Abbott sensitivity 81.0% (95% CI 60.0 – 92.3%). Less than 14 days of symptoms groups exhibited poor sensitivity at <50% for both assays. The area under curve (AUC ± standard error) for Roche (0.894 ± 0.025, P< .001) and Abbott (0.884 ± 0.026, P <.001) were very similar. Potential confounders for negative serological results include antiretroviral medication use and pauci-symptomatic patients. Conclusions: Specificities for high throughput Roche and Abbott immunoassays are excellent but users need to be cautious to interpret serological test results after 14 days of symptoms to avoid false negatives

No abstract

Influenza A virus (IAV) is responsible for severe morbidity and mortality in animals and humans worldwide. miRNAs are a class of small noncoding single-stranded RNA molecules that can negatively regulate gene expression and play important roles in virus-host interaction. However, the roles of miRNAs in IAV infection are still not fully understood. Here, we profiled the cellular miRNAs of A549 cells infected with A/goose/Jilin/hb/2003 (H5N1) and a comparison A/Beijing/501/2009 (H1N1). miRNA microarray and quantitative PCR analysis showed that several miRNAs were differentially expressed in A549 cells during IAV infection. Subsequently, we demonstrated that IAV replication was essential for the regulation of these miRNAs, and bioinformatic analysis revealed that the targets of these miRNAs affected biological processes relevant to IAV replication. Specifically, miR-21-3p was found to be down-regulated in IAV-infected A549 cells and selected for further detailed analysis. Target prediction and functional study illustrated that miR-21-3p repressed the expression of HDAC8 by targeting its 3′UTR. Furthermore, we confirmed miR-21-3p could promote virus replication, which was similar to the result of knocking down HDAC8, indicating that miR-21-3p promoted IAV replication by suppressing HDAC8 expression. Altogether, our results suggest a potential host defense against IAV through down-regulation of miR-21-3p.

No abstract

No abstract

No abstract

No abstract