Exploring the Non-Covalent Bonding in Water Clusters.

QTAIM and source function analysis were used to explore the non-covalent bonding in twelve different water clusters (HO) obtained by considering = 2-7 and various geometrical arrangements. A total of seventy-seven O-H⋯O hydrogen bonds (HBs) were identified in the systems under consideration, and the examination of the electron density at the bond critical point (BCP) of these HBs revealed the existence of a great diversity of O-H⋯O interactions. Furthermore, the analysis of quantities, such as |V(r)|/G(r) and H(r), allowed a further description of the nature of analogous O-H⋯O interactions within each cluster.

Interaction of the new inhibitor paxlovid (PF-07321332) and ivermectin with the monomer of the main protease SARS-CoV-2: A volumetric study based on molecular dynamics, elastic networks, classical thermodynamics and SPT.

The COVID-19 pandemic has accelerated the study of drugs, most notably ivermectin and more recently Paxlovid (PF-07321332) which is in phase III clinical trials with experimental data showing covalent binding to the viral protease M. Theoretical developments of catalytic site-directed docking support thermodynamically feasible non-covalent binding to M. Here we show that Paxlovid binds non-covalently at regions other than the catalytic sites with energies stronger than reported and at the same binding site as the ivermectin B1a homologue, all through theoretical methodologies, including blind docking.

Prophylactic Unfractionated Subcutaneous Heparin Does Not Increase Postoperative Hemorrhage in Elderly Patients Undergoing Emergency Neurosurgical Procedures.

Purpose The purpose of this study is to evaluate the impact in the development of intracerebral hemorrhage in elderly critically ill patients who received prophylactic subcutaneous unfractionated heparin (SCUFH) less than 24 hours after undergoing emergency neurosurgery.  Methods A retrospective analysis was performed on patients who underwent emergency neurosurgery and were admitted to the surgical intensive care unit (SICU) at a tertiary care center over a 10-year period. Administration of prophylactic SCUFH within 24 hours of neurosurgery was required for inclusion.