X-ray and neutron diffraction are particularly useful for characterizing ferroelectric materials in situ, e.g., during application of temperature, pressure, electric field, and stress. In this review, we introduce many experimental approaches for such measurements and highlight important discoveries in ferroelectrics that utilized diffraction. We focus our examples on polycrystalline ferroelectrics, though many of the approaches and analysis methods can also be applied to thin films and single crystals. Methods discussed for characterization of structure include, phase identification, line profile analysis, whole pattern fitting, pair distribution functions, and the x-ray diffraction based three-dimensional microscopy. Further advancement of these and other techniques offers potential for continued important contributions to the fundamental understanding of ferroelectric materials.

In situ nano-TiB2 reinforced ultrafine-grained (UFG) Al composites were prepared via combined processes of flux-assisted synthesis (FAS) and asymmetrical rolling (ASR). The UFG Al composite with an ASR reduction ratio of 97% exhibits an average matrix grain size of 380 nm and an average TiB2 particulate size of 50 nm. Dislocation density in the composites is higher than that corresponding to the high purity (99.99 wt%) Al under identical processing conditions. The yield and ultimate tensile strength values of the UFG Al composites processed with an ASR reduction ratio of 97% are approximately 9 and 5 times higher relative to those of the initial coarse-grained Al, respectively. Moreover, the UFG Al composite with an ASR reduction ratio of 97% exhibits a higher elongation than that corresponding to the UFG pure Al under identical processing conditions, suggesting that nanoparticulates contribute to the overall plastic deformation when the matrix grains are refined to the UFG regime. Moreover, analysis of the strengthening behavior reveals no clear evidence that Orowan strengthening contributes significantly to the overall yield strength of the Al nanocomposites studied herein.

Ag–TiO2 hybrids are useful in various applications, such as photocatalysis, solar energy conversion, and biosensoring. In this study, oil-decorated TiO2 films were used to induce the formation of Ag nanoplates in AgNO3 solution via a photocatalytic method. Ag nanoplates in the products can be controlled by changing the oil-decoration time of films or changing the AgNO3 concentration of the solution. Oil decoration was found to be necessary in the formation of Ag nanoplates, and a critical concentration of AgNO3 solution was needed. The oil layer on the TiO2 films was demonstrated to play a role in the prevention of the reoxidation of the Ag atoms, and a growth model was proposed to interpret the formation of Ag nanoplates on the oil-decorated TiO2 films.

Metal and metal oxide nanoparticles are an important class of materials with numerous applications. Understanding how such nanoparticles interact with living systems is of considerable relevance both from a toxicological and biomedical perspective. The physicochemical features of nanoparticles are sometimes referred to as the synthetic identity, while the acquired properties of nanoparticles in a biological milieu resulting from the adsorption of biomolecules on the surface of the particles can be considered the biological identity. In this article, we explore the dynamic changes in the identity of nanoparticles resulting either from acquisition of a so-called bio-corona or through the process of biotransformation and how this impacts cellular recognition of nanoparticles and toxicological outcomes, with an emphasis on inflammation—an orchestrated host response against harmful stimuli, including pathogens as well as particles.

Fast and significant progress has been achieved in the development of new biomarkers in recent years providing promising approaches for the reliable detection of diseases at an early stage. Yet, the disadvantages of commonly used markers, including photobleaching, autofluorescence, phototoxicity, and scattering, when ultraviolet or visible light is used for excitation, need to be overcome. Lanthanide-doped host materials are well known for their excellent optical properties, such as their ability to (up)convert near-infrared excitation to higher energies spanning the ultraviolet, visible, and near-infrared regions or to undergo strong near-infrared luminescence following near-infrared excitation. Their application as biomarkers may overcome the aforementioned drawbacks of conventional dyes. Thus, lanthanide-based nanostructures are highly promising candidates for cellular and small animal imaging, while the assessment of their cytotoxicity remains a crucial issue. Recent developments in the field of upconversion and near-infrared bioimaging focusing on some of the latest results obtained in in vitro and in vivo studies assessing the toxicity of lanthanide-based nanophosphors are highlighted in this review.

Engineered nanoparticles, in particular metal oxide nanoparticles, with their unique and novel properties, enable a plethora of new applications in various fields of research. These new properties have raised concerns about potential adverse effects for the environment and human health and are nowadays very controversial. A reliable, cost- and time-effective, rapid and mechanistic-based testing strategy is needed to replace current conventional phenomenological assessments. Today’s in vitro technology, providing human-based advanced cellular models representing different organ barriers such as skin, lung, placenta, or liver, may cover this need. The aim of this article is to present the current changes in (nano) toxicology strategies, the extent to which in vitro models have achieved general acceptance, and how the relevance of these models can further be improved using examples of selected metal oxide nanoparticles.

Engineered nanomaterials (ENMs) strongly interact with biomolecules and cells due to their similar size scales. Consequently, ENMs are beginning to emerge as new medical diagnostic tools, probes in cell biology, and delivery vehicles, compelling us to understand the interactions at the nano-bio interface. Optical spectroscopic tools are excellent probes to characterize ENMs and investigate their interactions with complex biological systems, including biomolecules, cells, and even whole animals alike. Here, we discuss the role of many optical spectroscopic techniques such as fluorescence, Raman, surface plasmon, and infrared spectroscopy in elucidating nano-bio interactions. While these spectroscopic tools have the ability to provide valuable information on ENM distribution in biosystems, ENM interaction with proteins, and the mechanisms by which ENMs elicit an adverse physiological response, there are many challenges that remain to be addressed to improve their scope, resolution, and throughput.