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Heteroaromatic stacking interactions are important in drug binding, supramolecular chemistry, and materials science, making protein-ligand model systems of these interactions of considerable interest. Here we studied 30 congeneric ligands that each present a distinct heteroarene for stacking between tyrosine residues at the dimer interface of procaspase-6. Complex X-ray crystal structures of 10 analogs showed that stacking geometries were well conserved, while high-accuracy computations showed that heteroarene stacking energy was well correlated with predicted overall ligand binding energies. Empirically determined KD values in this system thus provide a useful measure of heteroarene stacking with tyrosine. Stacking energies are discussed in the context of torsional strain, the number and positioning of heteroatoms, tautomeric state, and coaxial orientation of heteroarene in the stack. Overall, this study provides an extensive data set of empirical and high-level computed binding energies in a versatile new protein-ligand system amenable to studies of other intermolecular interactions.

The development of supportable, cost-effective, and high-performance nanoparticles (NPs) is one of the new examination points within penetrating applications. The consideration of tailorable nanoparticles offers the chance to figure out water-based drilling fluids (WBDFs) with upgraded properties, providing exceptional opportunities in the energy, oil, gas, water, or framework enterprises. In WBDFs, nano and micron materials are investigated to control their rheological properties and their influence. This paper aims to analyze the influence of nano Fe2O3 on the rheological behavior of drilling fluid muds under high temperatures and pressure. Additionally, we seek to identify the optimal concentration of iron oxide nanoparticles that maintain consistent rheology; we examined the interfering effects of shear rates and iron oxide nanoparticle temperature on the shear type of the changed depleting liquid in the Dibella oil field to make the penetrating activity efficient, realistic, and skilled. We observe that as the temperature increases, the water-based mud (WBM), plastic viscosity (PV), yield point (YP), and gel strength (Gs) decrease until the reject structure is disrupted. Therefore, we must proceed with our assessment using nano Fe2O3 to resolve the shortcomings of the slope framework. Six water-based mud cakes containing 0.5, 1, 1.5, 2, 2.5, and 3 g weight percent of iron oxide (Fe2O3) nanoparticles were prepared for this evaluation. The experimental outcomes revealed an optimal nanoparticle mixing of 2.5 g weight percent, which resulted in a 13.8% reduction in the API filtrate volume and a 40% reduction in filter cake thickness. At 300°F temperature and type 10.00 pressure, the results of our experiments consistently demonstrate a decrease of 14.77% in the rheological properties of PV and YP and 10 s and 10 min in the gel strength of carbon oxide nanoparticles. The YP–PV span is 2.7, and the yield strength is 11 lb/100 ft2. On the other hand, mud cake A, which contains 0.5 wt% NPs, loses 6 mL of fluid after 30 min. In contrast, drilling mud cake E, which is composed of 3 wt% NPs, shows a fluid loss of 5.1 mL in the API filter press test. Based on the Bingham plastic model, the maximum shear stress versus shear rate was observed for bentonite drilling muds E and F, with 2.5 wt% and 3 wt% NPs, respectively, and this result indicates that the use of nano Fe2O3 can effectively adjust the properties of drilling fluids.

Introduction and Objectives: Acute kidney injury (AKI) is prevalent and has deleterious effects on postoperative outcomes following liver transplantation (LT). The impact of nonselective beta-blockers (NSBBs) in patients with liver cirrhosis remains controversial. This study investigated the association between preoperative NSBB use and AKI after living donor LT (LDLT). Patients and Methods: We evaluated 2,972 adult LDLT recipients between January 2012 and July 2022. The patients were divided into two groups based on the preoperative NSBB use. Propensity score matched (PSM) and inverse probability of treatment weighting (IPTW) analyses were performed to evaluate the association between preoperative NSBB use and postoperative AKI. Multiple logistic regression analyses were also used to identify the risk factors for AKI. Results: The overall incidence of AKI was 1,721 (57.9%) cases. The NSBB group showed a higher incidence of AKI than the non-NSBB group (62.4% vs. 56.7%; P = 0.011). After PSM and IPTW analyses, no significant difference in the incidence of AKI was found between the two groups (Odds ratio, OR 1.13, 95% confidence interval, CI 0.93–1.37, P = 0.230, PSM analysis; OR 1.20, 95% CI 0.99–1.44, P = 0.059, IPTW analysis). In addition, preoperative NSBB use was not associated with AKI after multivariate logistic regression analysis (OR 1.16, 95% CI 0.96–1.40, P = 0.118). Conclusions: Preoperative NSBB use was not associated with AKI after LDLT. Further studies are needed to validate our results.