Self-referencing for quasi shot-noise-limited widefield transient microscopy.

Many applications of ultrafast and nonlinear optical microscopy require the measurement of small differential signals over large fields-of-view. Widefield configurations drastically reduce the acquisition time; however, they suffer from the low frame rates of two-dimensional detectors, which limit the modulation frequency, making the measurement sensitive to excess laser noise. Here we introduce a self-referenced detection configuration for widefield differential imaging. Employing regions of the field of view with no differential signal as references, we cancel probe fluctuations and increase the signal-to-noise ratio by an order of magnitude reaching noise levels only a few percent above the shot noise limit. We anticipate broad applicability of our method to transient absorption, stimulated Raman scattering and photothermal-infrared microscopies.

Challenges and opportunities in 2D heterostructures for electronic and optoelectronic devices.

Two-dimensional (2D) materials such as graphene, transition metal dichalcogenides (TMDs), and their heterojunctions are prospective materials for future electronics, optoelectronics, and quantum technologies. Assembling different 2D layers offers unique ways to control optical, electrical, thermal, magnetic, and topological phenomena. Controlled fabrications of electronic grade 2D heterojunctions are of paramount importance. Here, we enlist novel and scalable strategies to fabricate 2D vertical and lateral heterojunctions, consisting of semiconductors, metals, and/or semimetals. Critical issues that need to be addressed are the device-to-device variations, reliability, stability, and performances of 2D heterostructures in electronic and optoelectronic applications. Also, stacking order-dependent formation of moiré excitons in 2D heterostructures are emerging with exotic physics and new opportunities. Furthermore, the realization of 2D heterojunction-based novel devices, including excitonic and valleytronic transistors, demands more extensive research efforts for real-world applications. We also outline emergent phenomena in 2D heterojunctions central to nanoelectronics, optoelectronics, spintronics, and energy applications.

Phytochemical characterization of Styrax benzoin resin extract, molecular docking, ADME, and antibacterial activity study.

Styrax benzoin fumes have a spiritual aspect from ancient times, magical essence like a pleasant perfume, and are employed in religious ceremonies in India. This study aims to identify the volatile compounds in S. benzoin extract, their binding affinity to the bacterial target proteins, and study the antibacterial activity of the potential extract. The compounds obtained from GC-MS analysis of S. benzoin extract were subjected to molecular docking studies against DHFR of Staphylococcus aureus, tRNA synthetase of Escherichia coli, DHPS of Mycobacterium tuberculosis. Molecular docking studies revealed that seventeen compounds out of 20 compounds exhibited higher binding affinity than co-ligand (-7.00 kcal/mol) against the Staphylococcus aureus enzyme DHFR. Consequently, the crude extracts were evaluated for antibacterial activity against S. aureus, and the acetone extract showed promising findings. S. benzoin fumes might replace synthetic room fresheners, and promising compounds could be exploited in the cosmetics industry.