Dual-driven AND molecular logic gates for label-free and sensitive ratiometric fluorescence sensing and inhibitors screening.

Due to the complexity of regulatory networks of disease-related biomarkers, developing simple, sensitive, and accurate methods has remained challenging for precise diagnosis. Herein, an "AND" logic gates DNA molecular machine (LGDM) was constructed, which was powered by the catalytic hairpin assembly (CHA). It was coupled with dual-emission CdTe quantum dots (QDs)-based cation exchange reaction (CER) for label-free, sensitive, and ratiometric fluorescence detection of APE1 and miRNA biomarkers. Benefiting from synergistic signal amplification strategies and a ratiometric fluorometric output mode, this LGDM enables accurate logic computing with robust and significant output signals from weak inputs. It offers improved sensitivity and selectivity even in cell extracts. Using dual-emission spectra CdTe QDs, with a ratiometric signal output mode, ensured good stability and effectively prevented false-positive signals from intrinsic biological interferences compared to the approach relying on a single signal output mode, which enabled the LGDM to achieve rapid, efficient, and accurate natural drug screening against APE1 inhibitors in vitro and cells. The developed method provides impetus to streamline research related to miRNA and APE1, offering significant promise for widespread application in drug development and clinical analysis.

Velocity mismatch effect on the dynamic MTF of a TDI image sensor.

By analyzing the process of time delay integration dynamic imaging, we establish a model of velocity mismatch. Based on this model, we analyze the influence of different factors on the dynamic imaging process, and a modulation transfer function (MTF) is used to evaluate imaging quality. According to the simulation, the velocity mismatch and scan stage are the main factors for image quality. The MTF of the image sensor decreases with the velocity mismatch, and the scan stage increases. In addition, an image with higher contrast can be obtained in a short integration time. However, a shorter integration time leads to insufficient sampling. Furthermore, we establish a dynamic MTF testing system, and evaluate the experiment at different imaging modes. Through data comparison, the experimental data are consistent with theoretical data.

Control of periodic ripples growth on metals by femtosecond laser ellipticity.

Formation of the periodic ripples on metallic surfaces is investigated comprehensively using variable ellipticities of femtosecond lasers. Compared with the linearly polarized incidence, the well defined grating-like ripple structures rather than the uniform arrays of nanoparticle can always be obtained for the elliptical polarization lasers. The ripple orientation is slanted clockwise or anticlockwise depending on the laser helicity but always display a maximum angle of 45°. Theoretical analyses indicate that no circular polarization is achieved for femtosecond lasers passing through quarter waveplate, and the induced ripple orientation is determined by the major axis of the polarization ellipse. The simulation results agree well with the experimental observations.