Parental Perceptions of Their Children's Access to Household Firearms.

Objectives: To provide a nationally representative estimate of the proportion of gun owners who report a child has independent access to one of their guns, and to describe characteristics of these gun owners relative to other gun-owning parents.

Study Design: We conducted a cross-sectional analysis of online survey data collected in 2019 from a nationally representative sample of US adults in households with firearms (n = 4030, response 65%). The sample comprised gun-owning respondents living in homes with children (n = 689) who were asked questions about their firearms, including how they were stored, and about who other than themselves had access to their guns: "If you were not there, who in your household could get one of your guns (and load it if it is not loaded already) if they needed to?"

Results: Twelve percent of US gun owners in homes with children report that a child has independent access to one of their guns (about one-fifth of those having children under age 12 years only).

Machine learning-enabled feature classification of evaporation-driven multi-scale 3D printing.

The freeform generation of active electronics can impart advanced optical, computational, or sensing capabilities to an otherwise passive construct by overcoming the geometrical and mechanical dichotomies between conventional electronics manufacturing technologies and a broad range of three-dimensional (3D) systems. Previous work has demonstrated the capability to entirely 3D print active electronics such as photodetectors and light-emitting diodes by leveraging an evaporation-driven multi-scale 3D printing approach. However, the evaporative patterning process is highly sensitive to print parameters such as concentration and ink composition.

3D Printing of Supramolecular Polymer Hydrogels with Hierarchical Structure.

Liquid crystalline hydrogels are an attractive class of soft materials to direct charge transport, mechanical actuation, and cell migration. When such systems contain supramolecular polymers, it is possible in principle to easily shear align nanoscale structures and create bulk anisotropic properties. However, reproducibly fabricating and patterning aligned supramolecular domains in 3D hydrogels remains a challenge using conventional fabrication techniques.

Fatal police shootings of civilians, by rurality.

In the United States, firearm homicides disproportionately occur in urban areas. We examine whether the same is true for fatal police shootings. We use data on fatal police shootings from Washington Post's "Fatal Force Database" (2015-2017).

Hybrid 3D Printing of Soft Electronics.

Hybrid 3D printing is a new method for producing soft electronics that combines direct ink writing of conductive and dielectric elastomeric materials with automated pick-and-place of surface mount electronic components within an integrated additive manufacturing platform. Using this approach, insulating matrix and conductive electrode inks are directly printed in specific layouts. Passive and active electrical components are then integrated to produce the desired electronic circuitry by using an empty nozzle (in vacuum-on mode) to pick up individual components, place them onto the substrate, and then deposit them (in vacuum-off mode) in the desired location.