Synthesis of highly monodisperse Pd nanoparticles using a binary surfactant combination and sodium oleate as a reductant.

This study presents the synthesis of monodisperse Pd nanoparticles (NPs) stabilized by sodium oleate (NaOL) and hexadecyltrimethylammonium chloride (CTAC). The synthesis was conducted without traditional reductants and Pd-precursors are reduced by NaOL. It was confirmed that the alkyl double bond in NaOL is not the only explanation for the reduction of Pd-precursors since Pd NPs could be synthesized with CTAC and the saturated fatty acid sodium stearate (NaST). A quantitative evaluation of the reduction kinetics using UV-Vis spectroscopy shows that Pd NPs synthesized with both stabilizer combinations follow pseudo first-order reaction kinetics, where NaOL provides a faster and more effective reduction of Pd-precursors. The colloidal stabilization of the NP surface by CTAC and NaOL is confirmed by Fourier transform infrared (FTIR) and nuclear magnetic resonance (NMR) analysis.

Continuous Microfluidic Synthesis of Pd Nanocubes and PdPt Core-Shell Nanoparticles and Their Catalysis of NO2 Reduction.

Faceted colloidal nanoparticles are currently of immense interest due to their unique electronic, optical, and catalytic properties. However, continuous flow synthesis that enables rapid formation of faceted nanoparticles of single or multi-elemental composition is not trivial. We present a continuous flow synthesis route for the synthesis of uniformly sized Pd nanocubes and PdPt core-shell nanoparticles in a single-phase microfluidic reactor, which enables rapid formation of shaped nanoparticles with a reaction time of 3 min. The PdPt core-shell nanoparticles feature a dendritic, high surface area with the Pt shell covering the Pd core, as verified using high-resolution scanning transmission electron microscopy and energy dispersive X-ray spectroscopy. The Pd nanocubes and PdPt core-shell particles are catalytically tested during NO2 reduction in the presence of H2 in a flow pocket reactor. The Pd nanocubes exhibited low-temperature activity (i.e., <136 °C) and poor selectivity performance toward production of N2O or N2, whereas PdPt core-shell nanoparticles showed higher activity and were found to achieve better selectivity during NO2 reduction retaining its basic structure at relatively elevated temperatures, making the PdPt core-shell particles a unique, desirable synergic catalyst material for potential use in NOx abatement processes.

Synthesis of Cu Nanoparticles: Stability and Conversion into Cu2S Nanoparticles by Decomposition of Alkanethiolate.

A lean synthesis of copper nanoparticles (Cu NP) from CuCl2 in dodecane via formation of Cu(I)-dodecanethiolate (Cu(I)-DDT) and their decomposition paths including spontaneous C-S bond cleavage of the alkanethiol on the surface of Cu NP is presented. The reduction of Cu(I)-DDT by the tert-butylamine-borane complex (TBAB) in dodecane under N2 at elevated temperatures leads to the formation of thiol-protected Cu NP with narrow size distribution in the size range of 3-10 nm depending on the reaction conditions. The Cu NP in the presence of excess dodecanethiol reacts further to Cu2S NP under decomposition of the ligand on the particle surface. The Cu2S formation occurs after a short time at T > 175 °C or within ∼12 h at room temperature. If excess thiol is removed immediately after the synthesis, the resulting colloid shows irreversible aggregation within days or hours. Our results suggest that alkanethiols are not long-term stable on nanocopper surfaces and that the formation of copper(I) sulfide under the cleavage of the C-S bond occurs even at room temperature.

An affordable, computerised, table-based exercise system for stroke survivors.

PURPOSE: Loss of hand function as a result of upper limb paresis after a stroke leads to reduced independence. Robotic-assisted therapy with virtual reality leads to improvements in motor function, but there is a need to improve the cost-benefit ratio of these therapies. This case series study investigated augmented reality computer games which provided a rewarded, goal-directed task to upper limb rehabilitation via a gravity supported reaching task. METHODS: A computer game was developed to motivate chronic stroke survivors to undertake gravity supported reaching tasks performed on a table, and a focus group study investigated the application of this device for rehabilitation. From the focus group, a simple device was developed to improve the quality of the exercise and a further focus group study investigated a variety of computer games to determine motivations for undertaking rehabilitation exercises. RESULTS: Of the four participants in the case study, two showed improvement in ability to play the game and in arm function. Participants enjoyed playing a range of computer games and felt that the system provided a worthwhile exercise. Motivation for undertaking exercise with the system included: intellectual stimulation during game play, feedback such as game score, gaining physical benefits from the exercise, the system tolerating varying levels of disability, ability to relate to the game and ability to use the system in social groups. CONCLUSIONS: A low-cost device has been developed which increases the exercise of gravity supported reaching movements, provides goal-directed tasks with rewards and motivates the user to undertake extended rehabilitation.