Synthesis and characterization of core∕shell Fe(3)O(4)∕ZnSe fluorescent magnetic nanoparticles

We report on the successful preparation and characterization of fluorescent magnetic core∕shell Fe(3)O(4)∕ZnSe nanoparticles (NPs) with a spherical shape by organometallic synthesis. The 7 nm core∕3 nm shell NPs show good magnetic and photoluminescence (PL) responses. The observed PL emission∕excitation spectra are shifted to shorter wavelengths, compared to a reference ZnSe NP sample. A dramatic reduction of PL quantum yield is also observed. The temperature dependence of the magnetization for the core∕shell NPs shows the characteristic features of two coexisting and interacting magnetic (Fe(3)O(4)) and nonmagnetic (ZnSe) phases. Compared to a reference Fe(3)O(4) NP sample, the room-temperature Néel relaxation time in core∕shell NPs is three times longer.     

High‐Performance Doped Silver Films: Overcoming Fundamental Material Limits for Nanophotonic Applications

The field of nanophotonics has ushered in a new paradigm of light manipulation by enabling deep subdiffraction confinement assisted by metallic nanostructures. However, a key limitation which has stunted a full development of high‐performance nanophotonic devices is the typical large losses associated with the constituent metals. Although silver has long been known as the highest quality plasmonic material for visible and near infrared applications, its usage has been limited due to practical issues of continuous thin film formation, stability, adhesion, and surface roughness. Recently, a solution is proposed to the above issues by doping a proper amount of aluminum during silver deposition. In this work, the potential of doped silver for nanophotonic applications is presented by demonstrating several high‐performance key nanophotonic devices. First, long‐range surface plasmon polariton waveguides show propagation distances of a few centimeters. Second, hyperbolic metamaterials consisting of ultrathin Al‐doped Ag films are attained having a homogeneous and low‐loss response, and supporting a broad range of high‐k modes. Finally, transparent conductors based on Al‐doped Ag possess both a high and flat transmittance over the visible and near‐IR range.     

Antecedents and effects of perceived therapist credibility: A meta-analysis.

Published studies examining antecedents or effects (or both) of perceived therapist credibility were subjected to a meta-analytic review to test S. R. Strong's (1968) 2-phase model of interpersonal influence in counseling. Results conformed to the predictions of the model, with therapist credibility cues moderately related to credibility, and credibility strongly related to therapist influence. Cue type was a significant moderator of the relation between cues and credibility. Cue types were also differentially related to influence, but this relation was mediated by cue strength, or the relation of cues to credibility. Tests of differential reactivity among influence measures yielded equivocal results, as did tests of participant involvement as a moderator of the relation between cues and influence. It is suggested that a simple mediational model cannot fully account for the relations among cues, credibility, and influence. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Mesoporous Natural Fiber Welded Cellulose Containing Silver Nanoparticles as a Recyclable Heterogeneous Catalyst

Silver nanoparticles (AgNPs) are presented within mesoporous natural fiber welded (NFW) cellulose and demonstrated as robust catalysts to reduce 4-nitrophenol using sodium borohydride. Growing AgNPs this way enables their retention within a nonderivatized, mesoporous, all-cellulose NFW composite. At an AgNP loading of 1.0 wt%, no leaching is observed during rinsing with polar and nonpolar solvents or any of 12 catalyst cycles and the cloth is easily retrievable and reusable. Comparatively, a 1.0 wt% AgNP loading on non-NFW cotton thread loses ≈95% of the starting Ag under similar conditions. Only at higher loadings is a very slow leaching observed in the NFW composite (<10% Ag loss). With a turnover frequency of 0.9 h^–1 (as compared to 2.2 h^–1 for the non-NFW cotton thread), the catalytic activity suffers only minor impedance from the NFW structure while affording significant promise in future applications for leach-resistant nonderivatized cotton (e.g., TiO₂ or photonic nanomaterials). Finally, it is shown that combustion of AgNPs-NFW composites creates Ag residues distinct from materials produced via combustion of AgNPs on non-NFW cotton. While the residues produced comprise Ag and residual carbon, this method is viable for producing metal “sponges” from monometallic and bimetallic NPs on mesoporous cellulose.     

Front Cover: Chemoselective Labeling and Immobilization of Phosphopeptides with Phosphorimidazolide Reagents (ChemBioChem 4/2023)

Protein phosphorylation is one of the most ubiquitous post-translational modifications, regulating numerous essential processes in cells. Accordingly, the large-scale annotation of phosphorylation sites continues to provide central insight into the regulation of signaling networks. The global analysis of the phosphoproteome typically relies on mass spectrometry analysis of phosphopeptides, with an enrichment step necessary due to the sub-stoichiometric nature of phosphorylation. Several affinity-based methods and chemical modification strategies have been developed to date, but the choice of enrichment method can have a considerable impact on the results. Here, we show that a biotinylated, photo-cleavable phosphorimidazolide reagent permits the immobilization and subsequent cleavage of phosphopeptides. The method is capable of the capture and release of phosphopeptides of varying characteristics, and this mild and selective strategy expands the current repertoire for phosphopeptide chemical modification with the potential to enrich and identify new phosphorylation sites in the future.     

Adding wind power to a wind-rich grid: Evaluating secondary suitability metrics

As the quantity of renewable electricity generation from wind farms increases in a region, the costs associated with integrating it into the broader electricity system also grow. This is primarily due to the need for dispatchable generators that vary power output to compensate for wind farm power variations. Such “balancing services” are an economic cost to the system that is typically not passed on to wind farms. We propose including the use of technical merits other than capacity factor and cost of energy for evaluating new wind farm sites and present a new graphical geospatial method, with the intention of identifying sites that minimize the need for additional electricity balancing service and transmission congestion. Specifically, locations with low correlation to existing wind farms, locations with high correlation to load, locations with high characteristic power time-shift from existing wind farms, and locations that relieve or do not negatively impact electricity transmission congestion are identified. A geospatial Venn diagram-based method of visualization is presented. These methods will equip regional planners with new tools to encourage wind farm development in areas that benefit the electricity grid beyond the lowest bid price.     

Electrical Interrogation of Thickness-Dependent Multiferroic Phase Transitions in the 2D Antiferromagnetic Semiconductor NiI2

2D magnetic materials hold promise for quantum and spintronic applications. 2D antiferromagnetic materials are of particular interest due to their relative insensitivity to external magnetic fields and higher switching speeds compared to 2D ferromagnets. However, their lack of macroscopic magnetization impedes detection and control of antiferromagnetic order, thus motivating magneto-electrical measurements for these purposes. Additionally, many 2D magnetic materials are ambient-reactive and electrically insulating or highly resistive below their magnetic ordering temperatures, which imposes severe constraints on electronic device fabrication and characterization. Herein, these issues are overcome via a fabrication protocol that achieves electrically conductive devices from the ambient-reactive 2D antiferromagnetic semiconductor NiI₂. The resulting gate-tunable transistors show band-like electronic transport below the antiferromagnetic and multiferroic transition temperatures of NiI₂, revealing a Hall mobility of 15 cm² V⁻¹ s⁻¹ at 1.7 K. These devices also allow direct electrical probing of the thickness-dependent multiferroic phase transition temperature of NiI₂ from 59 K (bulk) to 28 K (monolayer).     

Thermal stability of MxOy-doped zirconia aerogels (M = Y,Yb, Gd,Ce, Ca) studied through 1200°C

The high porosities and low densities of ceramic aerogels offer outstanding insulative performance in applications where weight is a critical factor. The high surface area-to-volume ratios and specific surface areas provide extremely low thermal conductivity, but also contribute to rapid densification of the pore structure at elevated temperatures. This densification diminishes their favorable properties and inhibits use of aerogels in high-temperature applications. This work contributes to a design framework for thermally stable aerogels via the study of dopant chemistry (Y, Yb, Gd, Ca, Ce) in zirconia aerogels. The structural evolution was studied through 1200°C using nitrogen physisorption, scanning electron microscopy, and X-ray diffraction. The role of dopant identity and concentration in thermal stability was elucidated. In the context of the design framework, dopant chemistry is an aggregate for many closely related material properties, each of which may contribute to aerogel structural evolution. To develop a truly predictive design framework for ceramic-based aerogels, systematic and comprehensive evaluation of thermodynamic and kinetic properties must be performed in conjunction with studies on structural evolution.     

Sustainable Utilization of Waste Glass in Concrete: a Review

Silicon - Due to population growth and industrial development, waste generation has increased annually over the last few years. According to a World Bank report, in 2018, about 2.01 billion tons of...