Unimolecular net heterolysis of symmetric and homopolar σ-bonds.

The unimolecular heterolysis of covalent σ-bonds is integral to many chemical transformations, including S1-, E1- and 1,2-migration reactions. To a first approximation, the unequal redistribution of electron density during bond heterolysis is governed by the difference in polarity of the two departing bonding partners. This means that if a σ-bond consists of two identical groups (that is, symmetric σ-bonds), its unimolecular fission from the S, S, or T states only occurs homolytically after thermal or photochemical activation.

Evaluation of severe acute respiratory syndrome coronavirus 2 monoclonal antibodies in high-risk solid organ transplant recipients across three major coronavirus disease 2019 variant waves.

Background: Coronavirus disease 2019 (COVID-19) continues to impact immunocompromised populations including solid organ transplant recipients (SOTRs). Monoclonal antibodies (mAbs) have shown effectiveness in reducing COVID-19-related hospitalizations and emergency department (ED) visits in SOTRs at different time frames in the COVID-19 pandemic; however, less data exist on the impact of mAbs for SOTRs across variant waves and with the advent of available COVID-19 vaccines.

Methods: This retrospective study included SOTR outpatients who tested positive for SARS-CoV-2 and received mAbs from December 2020 to February 2022 (n = 233); using in-house sequencing of clinical samples, we monitored the emergence of Alpha, Delta, and Omicron variants.

Integration of Impedimetric Sensors for In Situ Electrochemical Impedance Spectroscopy in Free-Flow Electrophoresis Applications in Lab-on-Chip Systems.

Miniaturization and integration of chemical reactions into fluidic systems in combination with product purification or buffer exchange can reduce the amount of solvents and reactants required while increasing synthesis efficiency. A critical step is the regulation of flow rates to realize optimal synthesis conditions and high purification rates, so real-time, label-free monitoring is required in methods such as free-flow electrophoresis. Optical detection methods are widely used, but they often have complex excitation and detection setups that are disadvantageous for point-of-care applications.

Real-world effectiveness of early remdesivir and sotrovimab in the highest-risk COVID-19 outpatients during the Omicron surge.

Background: Remdesivir and sotrovimab both have clinical trial data in the outpatient setting demonstrating reduction in the risk of hospitalizations and emergency department (ED) visits related to COVID-19.

Objectives: To evaluate the effectiveness of remdesivir in comparison with sotrovimab and matched high-risk control patients in preventing COVID-19-related hospitalizations and ED visits during the Omicron B.1.