Advances in modeling transport phenomena in material-extrusion additivemanufacturing: Coupling momentum, heat, and mass transfer

Material-extrusion (MatEx) additive manufacturing involves layer-by-layer assembly ofextruded material onto a printer bed and has found applications in rapid prototyping.Both material and machining limitations lead to poor mechanical properties of printedparts. Such problems may be addressed via an improved understanding of thecomplex transport processes and multiphysics associated with the MatEx process.Thereby, this review paper describes the current (last 5 years) state of the art modelingapproaches based on momentum, heat and mass transfer that are employed in aneffort to achieve this understanding. We describe how specific details regardingpolymer chain orientation, viscoelastic behavior and crystallization are often neglectedand demonstrate that there is a key need to couple the transport phenomena. Such acombined modeling approach can expand MatEx applicability to broader applicationspace, thus we present prospective avenues to provide more comprehensive modelingand therefore new insights into enhancing MatEx performanc

Similarities and differences between crystal and enzyme environmental effects on the electron density of drug molecules

The crystal interaction density is generally assumed to be a suitable measure of the polarization of a low‐molecular weight ligand inside an enzyme, but this approximation has seldomly been tested and has never been quantified before. In this study, we compare the crystal interaction density and the interaction electrostatic potential for a model compound of loxistatin acid (E64c) with those inside cathepsin B, in solution and in vacuum. We apply QM/MM calculations and experimental quantum crystallography to show that the crystal interaction density is indeed very similar to the enzyme interaction density. Less than 0.1e are shifted between these two environments in total. However, this has non‐negligible consequences for derived properties