"Direct and indirect impacts of the COVID-19 pandemic on operational conduct of pediatric vaccine clinical trials".

The coronavirus 2019 (COVID-19) pandemic, as well as the resulting public health measures, impacted many aspects of society. The conduct of important pediatric vaccine trials was among these. Analyzing data from six ongoing non-COVID-19 pediatric vaccine trials we aimed to assess the operational impact of the COVID-19 pandemic using descriptive analyses.

Conformal Volumetric Grayscale Metamaterials.

Conformal artificial electromagnetic media that feature tailorable responses as a function of incidence wavelength and angle represent universal components for optical engineering. Conformal grayscale metamaterials are introduced as a new class of volumetric electromagnetic media capable of supporting highly multiplexed responses and arbitrary, curvilinear form factors. Subwavelength-scale voxels based on irregular shapes are designed to accommodate a continuum of dielectric values, enabling the freeform design process to reliably converge to exceptionally high figures of merit (FOMs) for a given multi-objective design problem.

Thermoelectric response from grain boundaries and lattice distortions in crystalline gold devices.

The electronic Seebeck response in a conductor involves the energy-dependent mean free path of the charge carriers and is affected by crystal structure, scattering from boundaries and defects, and strain. Previous photothermoelectric (PTE) studies have suggested that the thermoelectric properties of polycrystalline metal nanowires are related to grain structure, although direct evidence linking crystal microstructure to the PTE response is difficult to elucidate. Here, we show that room temperature scanning PTE measurements are sensitive probes that can detect subtle changes in the local Seebeck coefficient of gold tied to the underlying defects and strain that mediate crystal deformation.

High-Throughput Growth of Microscale Gold Bicrystals for Single-Grain-Boundary Studies.

The study of grain boundaries is the foundation to understanding many of the intrinsic physical properties of bulk metals. Here, the preparation of microscale thin-film gold bicrystals, using rapid melt growth, is presented as a model system for studies of single grain boundaries. This material platform utilizes standard fabrication tools and supports the high-yield growth of thousands of bicrystals per wafer, each containing a grain boundary with a unique <111> tilt character.