Applications of second harmonic generation (SHG)/sum-frequency generation (SFG) imaging for biophysical characterization of the plasma membrane

Interfacial interactions between minerals and organic matter: Mechanisms and characterizations

Minerals and organic matter are essential components of soil, with minerals acting as the "bone" and organic matter as the "skin". The interfacial interactions between minerals and organic matter result in changes in their chemical composition, structure, functional groups, and physical properties, possessing a significant impact on soil properties, functions, and biogeochemical cycles. Understanding the interfacial interactions of minerals and organic matter is imperative to advance soil remediation technologies and carbon targets. Consequently, there is a growing interest in the physicochemical identification of the interfacial interactions between minerals and organic matter in the academic community. This review provides an overview of the mechanisms underlying these interactions, including adsorption, co-precipitation, occlusion, redox, catalysis and dissolution. Moreover, it surveys various methods and techniques employed to characterize the mineral-organic matter interactions. Specifically, the up-to-date spectroscopic techniques for chemical information and advanced microscopy techniques for physical information are highlighted. The advantages and limitations of each method are also discussed. Finally, we outline future research directions for interfacial interactions and suggests areas for improvement and development of characterization techniques to better understand the mechanisms of mineral-organic matter interactions.

Electric-field induced second harmonic generation responses of push-pull polyenic dyes: experimental and theoretical characterizations

The second-order nonlinear optical properties of four series of amphiphilic cationic chromophores involving different push-pull extremities and increasingly large polyenic bridges have been investigated both experimentally, by means of electric field induced second harmonic (EFISH) generation, and theoretically, using a computational approach combining classical molecular dynamics (MD) and quantum chemical (QM) calculations. This theoretical methodology allows to describe the effects of structural fluctuations on the EFISH properties of the complexes formed by the dye and its iodine counterion, and provides a rationale to EFISH measurements. The good agreement between experimental and theoretical results proves that this MD + QM scheme constitutes a useful tool for a rational, computer-aided, design of SHG dyes.

Biophysical Reviews: Turning the page from 2022 to 2023

This Editorial (vol. 15 issue 1-Regular Issue featuring an Issue Focus on the "100th Anniversary of Har Gobind Khorana") first describes the issue contents before providing both, a look back at some journal highlights from 2022, and a look forward to what we can expect from 2023. The Editorial closes with a roundup of new journal access features and an acknowledgement of those supporting the journal.

Long-ranged heterogeneous structure in aqueous solutions of the deep eutectic solvent choline and geranate at the liquid-vapor interface

The deep eutectic solvent choline and geranate (CAGE) has shown promise in many therapeutic applications. CAGE facilitates drug delivery through unique modes of action making it an exciting therapeutic option. We examine the behavior of aqueous CAGE solutions at a liquid-vapor interface. We find that the liquid-vapor interface induces large oscillations in the density, which corresponds to spontaneous segregation into regions enriched with geranate and geranic acid and other regions enriched with water and choline. These heterogeneities are observed to extend nanometers into the liquid. Additionally, we find that the geranate and geranic acid orient so that their polar carboxyl or carboxylate groups are on average pointed toward the layer containing water and choline. Finally, we report surface tension and thermal expansion coefficients for various concentrations of aqueous CAGE. We find a non-monotonic trend in the surface tension with concentration. The structural and thermodynamic properties we report provide a new perspective on CAGE behavior, which helps deduce the action of CAGE in more sophisticated systems and inspire other studies and applications of CAGE and related materials.

Biophysical Reviews: 2020-looking back, going forward

After first describing the issue contents (Biophysical Reviews-Volume 12 Issue 6), this Editorial goes on to provide a short round-up of the activities of the journal in 2020. Directly following this Editorial are two obituaries marking the recent deaths of Prof. Fumio Oosawa (Japan) and Dr. Herbert Tabor (USA)-two major figures in Biophysical/Biochemical science from the last 100 years.