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Abstract Measuring the three-dimensional (3D) distribution of chemistry in nanoscale matter is a longstanding challenge for metrological science. The inelastic scattering events required for 3D chemical imaging are too rare, requiring high beam exposure that destroys the specimen before an experiment is completed. Even larger doses are required to achieve high resolution. Thus, chemical mapping in 3D has been unachievable except at lower resolution with the most radiation-hard materials. Here, high-resolution 3D chemical imaging is achieved near or below one-nanometer resolution in an Au-Fe3O4 metamaterial within an organic ligand matrix, Co3O4-Mn3O4 core-shell nanocrystals, and ZnS-Cu0.64S0.36 nanomaterial using fused multi-modal electron tomography. Multi-modal data fusion enables high-resolution chemical tomography often with 99% less dose by linking information encoded within both elastic (HAADF) and inelastic (EDX/EELS) signals. We thus demonstrate that sub-nanometer 3D resolution of chemistry is measurable for a broad class of geometrically and compositionally complex materials.

Machine learning (ML) is gaining popularity as a tool for materials scientists to accelerate computation, automate data analysis, and predict materials properties. The representation of input material features is critical to the accuracy, interpretability, and generalizability of data-driven models for scientific research. In this Perspective, we discuss a few central challenges faced by ML practitioners in developing meaningful representations, including handling the complexity of real-world industry-relevant materials, combining theory and experimental data sources, and describing scientific phenomena across timescales and length scales. We present several promising directions for future research: devising representations of varied experimental conditions and observations, the need to find ways to integrate machine learning into laboratory practices, and making multi-scale informatics toolkits to bridge the gaps between atoms, materials, and devices.

Electron ptychography is a powerful computational method for atomic-resolution imaging with high contrast for weakly and strongly scattering elements. Modern algorithms coupled with fast and efficient detectors allow imaging specimens with tens of nanometers thicknesses with sub-0.5 Ångstrom lateral resolution. However, the axial resolution in these approaches is currently limited to a few nanometers, limiting their ability to solve novel atomic structures ab initio . Here, we experimentally demonstrate multi-slice ptychographic electron tomography, which allows atomic resolution three-dimensional phase-contrast imaging in a volume surpassing the depth of field limits. We reconstruct tilt-series 4D-STEM measurements of a $\mathrm{Co_3O_4}$ nanocube, yielding 2 Å axial and 0.7 Å transverse resolution in a reconstructed volume of $\mathrm{(18.2\,nm)^3}$ . Our results demonstrate a 13.5-fold improvement in axial resolution compared to multi-slice ptychography while retaining the atomic lateral resolution and the capability to image volumes beyond the depth of field limit. Multi-slice ptychographic electron tomography significantly expands the volume of materials accessible using high-resolution electron microscopy. We discuss further experimental and algorithmic improvements necessary to also resolve single weakly scattering atoms in 3D.

We retrospectively analyzed therapeutic strategies and risk factors for overall survival (OS) in disease recurrence following curative nephrectomy for localized renal cell carcinoma (loRCC) using the Korean National Cancer Registry Database. We selected 1295 recurrent loRCC patients who underwent either partial or radical nephrectomy from 2007–2013. Patients were excluded for age

Galvanic replacement reactions provide a simple and versatile route for producing hollow nanostructures with controllable pore structures and compositions. However, these reactions have previously been limited to the chemical transformation of metallic nanostructures. We demonstrated galvanic replacement reactions in metal oxide nanocrystals as well. When manganese oxide (Mn3O4) nanocrystals were reacted with iron(ll) perchlorate, hollow box-shaped nanocrystals of Mn3O4/ɣ-Fe3O4 ("nanoboxes") were produced. These nanoboxes ultimately transformed into hollow cagelike nanocrystals of ɣ-Fe3O4 ("nanocages"). Because of their nonequilibrium compositions and hollow structures, these nanoboxes and nanocages exhibited good performance as anode materials for lithium ion batteries. The generality of this approach was demonstrated with other metal pairs, including Co3O4/SnO2 and Mn3O4/SnO2. [ABSTRACT FROM AUTHOR]