The outbreak of 2019 coronavirus disease has been a challenge for hospital laboratories because of the huge number of samples that must be tested for the presence of the causative pathogen, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Simple and rapid immunodiagnostic methods are urgently needed to identify positive cases. Here we report the development of a rapid and sensitive lateral flow immunoassay (LFIA) that uses lanthanide-doped polysterene nanoparticles (LNPs) to detect anti-SARV-CoV-2 IgG in human serum. A recombinant nucleocapsid phosphoprotein of SARS-CoV-2 was dispensed onto a nitrocellulose membrane to capture specific IgG. Mouse anti-human IgG antibody was labeled with self-assembled LNPs that served as a fluorescent reporter. A 100-μL aliquot of serum samples (1:1000 dilution) was used for this assay and the whole detection process took 10 min. The results of the validation experiment met the requirements for clinical diagnostic reagents. A value of 0.0666 was defined as the cutoff value by assaying 51 normal samples. We tested 7 samples that were positive by reversetranscription (RT-)PCR and 12 that were negative but clinically suspicious for the presence of anti-SARS-CoV-2 IgG. One of the negative samples was determined to be SARS-CoV-2 IgG positive, while the results for the other samples were consistent with those obtained by RT-PCR. Thus, this assay can achieve rapid and sensitive detection of anti-SARS-CoV-2 IgG in human serum and allow positive identification in suspicious cases; it can also be useful for monitoring the progression COVID-19 and evaluating patients' response to treatment.

Sirt6, a member of the mammalian sirtuin family, is a protein that is located in the nucleus and is an NAD+‑dependent deacetylase important in the control of metabolic activity and genome stability. Recently, several studies have demonstrated the potential role of Sirt6 in tumor biology; however, the role of Sirt6 in hepatocellular carcinoma (HCC) remains unclear. In the present study, Sirt6 protein expression was found to be downregulated in human HCC tissue compared with adjacent normal tissue. Knockdown of Sirt6 promoted growth of the HepG2 HCC cell line, whereas overexpression of Sirt6 inhibited the growth of HepG2 cells. Overexpression of Sirt6 induced apoptosis in HepG2 cells, which was demonstrated by a terminal deoxynucleotidyl-transferase-mediated dUTP nick end labeling assay and cleaved caspase-3 immunoblotting. Furthermore, overexpression of Sirt6 decreased intracellular reactive oxygen species and superoxide anion levels. Finally, overexpression of Sirt6 inhibited phosphorylation of extracellular signal-regulated kinases 1/2 (ERK1/2), and blocking the ERK1/2 pathway with chemical-specific inhibitor U0126, attenuated the tumor suppressive effect of overexpression of Sirt6. Collectively, these data suggest that Sirt6 is a tumor suppressor in HCC cells and may be a promising therapeutic target in HCC.

No abstract

No abstract

Simple, rapid SA-MPs based TRFIA, is applied in therapeutic drug monitoring and the analytical performance is comparable with LC-MS/MS.

Development of sensitive homogeneous assays is a high-priority research target for clinical diagnostics. Quantum dots (QDs) present favorable photophysical properties, which implies their potential as an exceptional dye in fluorescence detection. QDs-based biosensors have been described in the literature; however, few of them have truly progressed to widespread clinical usage. In this work, a chemiluminescent homogeneous detecting biosensor is fabricated using QDs-doped polystyrene nanospheres to sensitively detect biomarkers in low-volume serum samples. Phthalocyanine-dyed and QDs-encapsulated carboxylate-functionalized polystyrene nanospheres with surface carboxyl groups (PPs and QPs, respectively) were fabricated and served as triggers and fluorescent probes, respectively, in this biosensing system. In this sandwich-format immunoassay, the PPs produced singlet oxygen once sensitized by 680 nm diode lasers, and the QPs, conjugated with antibodies, and then reacted with the singlet oxygen in the presence of specific antigens and emitted anti-Stokes fluorescence with wavelengths around 605 nm, as a result of fluorescence resonance energy transfer (FRET) within the QPs. We demonstrated the determination of carcinoembryonic antigen as a model protein target in 25 μL of serum samples with an unprecedented detection limit of 2.56 × 10–13 M (46 pg/mL) using this biosensor. Furthermore, excellent correlations (R 2 = 0.99718, n = 107) were obtained between utilizing this biosensor and commercialized chemiluminescence immunoassay kits in clinical serum detection. These results demonstrate that our flexible and reliable biosensor is suitable for direct integration into clinical diagnostics, and it is expected to be a promising diagnostic tool for early detection and screening tests as well as prognosis evaluation for patients.

No abstract

The Shack–Hartmann wavefront sensor (SHWFS) has been widely used for measuring aberrations in adaptive optics systems. However, its traditional wavefront reconstruction method usually has limited precision under field conditions because the weight-of-center calculation is affected by many factors, such as low signal-to-noise-ratio objects, strong turbulence, and so on. In this paper, we present a ResNet50+ network that reconstructs the wavefront with high precision from the spot pattern of the SHWFS. In this method, a nonlinear relationship is built between the spot pattern and the corresponding Zernike coefficients without using a traditional weight-of-center calculation. The results indicate that the root-mean-square (RMS) value of the residual wavefront is 0.0128 μm, which is 0.79% of the original wavefront RMS. Additionally, we can reconstruct the wavefront under atmospheric conditions, if the ratio between the telescope aperture’s diameter D and the coherent length r 0 is 20 or if a natural guide star of the ninth magnitude is available, with an RMS reconstruction error of less than 0.1 μm. The method presented is effective in the measurement of wavefronts disturbed by atmospheric turbulence for the observation of weak astronomical objects.