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This review consolidates the evidence supporting endogenous HNO generation through enzymatic and non‐enzymatic pathways, emphasizing advancements in real‐time HNO sensing within living systems. Azanone (nitroxyl, HNO) is the one‐electron‐reduced congener of nitric oxide (NO•) and shares various biological actions. HNO exhibits unique properties, including positive inotropic and lusitropic effects, along with resistance to scavenging by reactive oxygen species (ROS), particularly superoxide. Research on HNO has intensified over the last two decades, focusing on its reactivity and the prospect of endogenous formation due to its potential significance. The high reactivity of HNO arises from reactions with biologically relevant species such as oxygen, NO•, and thiols, as well as self‐dimerization. Detecting and quantifying HNO has posed challenges, initially relying on nitrous oxide (N2O) detection, a byproduct of dimerization. Recent advancements, including fluorescent probes and a specific electrochemical nanomolar‐level sensor, have facilitated direct detection, enhancing understanding of HNO reactivity and formation. [ABSTRACT FROM AUTHOR]

Switching elements are crucial components in electrical and electronic systems that undergo severe degradation due to the electrical arc that is generated during breaking. Understanding the behavior of the electrical arc and modifying its characteristics via proper electrode design can significantly improve durability while also promoting optimal performance, reliability, and safety in circuit breakers. This work evaluates the feasibility of carbon nanotube (CNT)-reinforced silver and copper metal matrix composites (MMCs) as switching electrodes and the influence of CNT concentration on the characteristics of the arcs generated. Accordingly, three different concentrations per MMC were manufactured via powder metallurgy. The MMCs and reference materials were subjected to a single break operation and the electrical arcs generated using 100 W and 200 W resistive loads were analyzed. The proposed MMCs displayed promising results for application in low-voltage switches. The addition of CNTs improved performance by maintaining the arc's energy in the silver MMCs and reducing the arc's energy in the copper MMCs. Moreover, a CNT concentration of at least 2 wt.% is required to prevent unstable arcs in both metallic matrices. Increased CNT content further promotes the splitting of the electrical arc due to a more complex phase distribution, thereby reducing the arc's spatial energy density. [ABSTRACT FROM AUTHOR]

From the historical roots of metalworking to the forefront of modern nanotechnology, functional materials have played a pivotal role in transforming societies, and their influence is poised to persist into the future. Encompassing a wide array of solid‐state materials, spanning semiconductors to polymers, molecular crystals to nanoparticles, functional materials find application in critical sectors such as electronics, computers, information, communication, biotechnology, aerospace, defense, environment, energy, medicine and consumer products. This feature article delves into diverse instances of functional materials, exploring their structures, their properties and the underlying mechanisms that contribute to their outstanding performance across fields like batteries, photovoltaics, magnetics and heterogeneous catalysts. The field of structural sciences serves as the cornerstone for unraveling the intricate relationship between structure, dynamics and function. Acting as a bridge, it connects the fundamental understanding of materials to their practical applications. [ABSTRACT FROM AUTHOR]

The rise in electrification has considerably increased the demand for high-efficiency and durable electrical contact materials. Carbon nanoparticles (CNP) are a promising coating material due to their intrinsic transport properties (thus minimizing the impact on conductivity), their proven solid lubricity (potentially improving tribological performance), and their hydrophobic wetting behavior (potentially providing atmospheric protection). In this study, carbon nanotube and nanohorn coatings are produced via electrophoretic deposition on silver-plated surfaces, followed by tribo-electrical and wetting characterization. The proposed coatings do not negatively affect the conductivity of the substrate, showing resistance values on par with the uncoated reference. Tribo-electrical characterization revealed that the coatings reduce adhesive wear during fretting tests while maintaining stable and constant electrical contact resistance. Furthermore, CNP-coated surfaces show a hydrophobic wetting behavior toward water, with graphite and carbon nanotube (CNT) coatings approaching super-hydrophobicity. Prolonged exposure to water droplets during sessile drop tests caused a reduction in contact angle (CA) measurement; however, CNT coatings' CA reduction after five minutes was only approximately 5°. Accordingly, CNP (specifically CNT) coatings show auspicious results for their application as wear and atmospheric protective barriers in electrical contacts. [ABSTRACT FROM AUTHOR]

Heuristics are simple, yet effective, strategies that people use to make decisions. Because heuristics do not require all available information, they are thought to be easy to implement and to not tax limited cognitive resources, which has led heuristics to be characterized as fast-and-frugal. We question this monolithic conception of heuristics by contrasting the cognitive demands of two popular heuristics, Tallying and Take-the-Best. We contend that heuristics that are frugal in terms of information usage may not always be fast because of the attentional control required to implement this focus in certain contexts. In support of this hypothesis, we find that Take-the-Best, while being more frugal in terms of information usage, is slower to implement and fares worse under time pressure manipulations than Tallying. This effect is then reversed when search costs for Take-the-Best are reduced by changing the format of the stimuli. These findings suggest that heuristics are heterogeneous and should be unpacked according to their cognitive demands to determine the circumstances a heuristic best applies.

Carbon nanotube (CNT)-reinforced silver and copper metal matrix composites—at three different reinforcement phase concentrations (0.5 wt.%, 0.75 wt.%, and 1 wt.%)—were produced via powder metallurgy and sintered via hot uniaxial pressing. Optical and electron microscopy techniques were used to characterize the powder mixtures and sintered composites. The latter were also electrically characterized via load-dependent electrical contact resistance (ECR) and surface fatigue tests. Particle size and morphology play a crucial role in CNT deposition onto the metallic powder. CNT were deposited exceptionally well onto the dendritic copper powder regardless of its larger size (compared with the silver flakes) due to the higher surface area caused by the grooves and edges of the dendritic structures. The addition of CNT to the metallic matrices improved their electrical performance, in general outperforming the reference material. Higher CNT concentrations produced consistently low ECR values. In addition, high CNT concentrations (i.e., 1 wt.%) show exceptional contact repeatability due to the elastic restitutive properties of the CNT. The reproducibility of the contact surface was further evaluated by the fatigue tests, where the composites also showed lower ECR than the reference material, rapidly reaching steady-state ECR within the 20 fatigue cycles analyzed. [ABSTRACT FROM AUTHOR]

At the beginning of his youthful sixth decade, this work is dedicated to Prof. Dr. Fabio Doctorovich. He is distinctive in organometallic chemistry. During his successful career, he has been studying the reactivity and application of metalloporphyrins. Metalloporphyrins are organometallic complexes that exhibit, through synthetic modifications, the ability to tune their optical and electrochemical properties and their selectivity towards a particular molecule or ion. For this reason, they are systems extremely useful as electrochemical sensors to detect and quantify a wide variety of analytes with high selectivity, even in real samples such as food, water, biological fluids, or pharmaceutical compounds. This review presents an up‐to‐date list of reports in which metalloporphyrins are used as electrochemical sensors. In addition to compiling a comprehensive and up‐to‐date list of reported sensors that utilize metalloporphyrins, this work aims to provide an overview of currently available tools and techniques for the detection of various chemical species through similar approaches, which are constantly being developed. [ABSTRACT FROM AUTHOR]

When lubrication of rolling bearings with oil or grease is not possible, for example because the lubricant evaporates in vacuum, solid lubrication by multiwall carbon nanotubes (MWCNT) is a viable alternative. To understand the mechanisms underlying MWCNT lubrication of highly loaded contacts, we combine an experimental approach with large-scale molecular dynamics (MD) simulations. Tribometry is performed on ground iron plates coated with two different types of MWCNTs by electrophoretic deposition. Although structural differences in the MWCNT materials result in slightly different running-in behavior, most of the tests converge to a steady-state coefficient of friction of 0.18. The resulting wear tracks and tribolayers are subjected to structural and chemical characterization and suggest a tribo-induced phase transformation resulting in tribolayers that consist of MWCNT fragments, iron oxide, and iron carbide nanoparticles embedded in an amorphous carbon matrix. Covalent bonding of the tribolayer to the iron surface and low carbon transfer to the alumina counter body indicate sliding at the tribolayer/ball interface as the dominant mechanism underlying MWCNT solid lubrication. MD simulations of nascent a-C tribofilms lubricated by MWCNT bundles and stacks of crossed MWCNTs reveal two different sliding regimes: a low-load regime that leaves the MWCNTs intact and a high-load regime with partial collapse of the tube structure and formation of a-C regions. The critical load for this transition increases with the filling ratio of the MWCNT and the packing density of the stacks. The former determines the stability of the MWCNT, while the latter controls the local stresses at the MWCNT crossings. For both MWCNT materials, the high-load regime is predicted for the experimental loads. This is confirmed by a remarkable agreement between transmission electron microscopy (TEM) and atomistic simulation images. Based on the findings of this work, a multistep lubrication mechanism is formulated for MWCNT coatings rubbing against alumina on an iron substrate. [ABSTRACT FROM AUTHOR]

In this study, we report on phase formation and microstructure evolution in multiscale magnetron sputtered Ru/Al multilayers upon thermal annealing in vacuum at slow heating rates of 10 K/min. By specifically adjusting the microstructure and design of the as-deposited multilayers, the formation of certain desired phases can be tuned. We demonstrate that the synthesis of single phase RuAl thin films is possible in a very controlled manner in a solid state only via thermal activation without initiating the self-propagating exothermic reactions of Ru/Al multilayers. To investigate phase formation sequences and the resulting microstructures, Ru/Al multilayers were designed via magnetron sputtering with systematic variation of bilayer modulation periods and subsequent vacuum annealing. Thin films samples were characterized by in situ high-temperature XRD, TEM imaging and diffraction. It is shown that different phase sequences appear in strong correlation with the modulation length. Depending on the multilayer design, the phase formation toward single-phase RuAl thin films happens as either a multi-step or single-step event. In particular, below a critical threshold of the modulation period, the multi-step phase formation can be suppressed, and only the desired RuAl target phase is obtained with a pronounced growth in a preferred orientation. This finding may be versatile for the targeted synthesis of intermetallic phases, contributing to further understanding of phase formation in such nanoscale multilayer systems. [ABSTRACT FROM AUTHOR]