Facile Synthesis of Ge@TiO2 Nanotube Hybrid Nanostructure Anode Materials for Li-Ion Batteries.

Utilizing nanostructures of Li-alloying anode materials (e.g., Si, Ge, Sn, etc.) has been proposed as a key strategy to improve the electrochemical performance. However, the main challenge lies in the costly and complex nanostructure synthesis processes. Notably, the nanostructure growth processes are mainly supported by Li-inactive templates, which later need to be removed, and the template removal process results in the destruction of the desired nanostructures. In this report, we demonstrated the use of a Li-active, self-organized TiO2 nanotube template to fabricate germanium (Ge)-based nanostructured anodes. This has been achieved as follows: first, TiO2 nanotubes are fabricated via electrochemical anodization of titanium foil. Then, the nanotubes are coated with a Ge film in the second step via electrodeposition. Besides the effective nanostructure growth using a Li-active template, the implemented electrochemical synthesis methods are cost-effective, accessible, and scalable. Furthermore, the electrochemical methods allow the fabrication of nanostructures with well-controlled structures, morphology, and compositions. Accordingly, a Ge-coated TiO2 nanotube (Ge@TiO2) nanocomposite anode has been successfully fabricated, and its electrochemical performance has been tested for Li-ion batteries. The study has shown the important roles of TiO2 nanotube arrays in improving the performance by providing strong mechanical support to buffer the volume expansion and offering a high surface area to enhance Ge-active mass loading. Moreover, the direct contact of the nanotubes with a Ti current collector facilitates one-dimensional (1D) electron transport and avoids the need of adding inactive binders or conductive additives.

Growth of Homogeneous Luminescent Silicon-Terbium Nanowires by One-Step Electrodeposition in Ionic Liquids.

An electrodeposition method for the growth of homogeneous silicon-terbium nanowires (NWs) with green light emission is described. The method involves template-assisted electrochemical co-deposition of Si/Tb NWs with 90-nm diameter from an electrolyte bath containing Si and Tb precursors in an ionic liquid (IL). This method of deposition is advantageous over other conventional techniques as it is relatively simple and cost-effective and avoids harsh deposition conditions. The deposited NWs are of uniform dimensions with homogeneous composition incorporating 10% of Tb and exhibit intense room temperature (RT) luminescence in the visible range due to Tb emission. These results were confirmed by combining classical characterization such as scanning electron microscopy (SEM) and photoluminescence (PL) performed on an assembly of NWs with spatially resolved experiments such as transmission electron microscopy (TEM) and cathodoluminescence (CL). This electrodeposition method provides an alternative and extremely simple approach for depositing silicon-rare earth nanostructures for optical and sensing applications.

Single step electrodeposition process using ionic liquid to grow highly luminescent silicon/rare earth (Er, Tb) thin films with tunable composition.

A one-step method for the electrodeposition of silicon-erbium (Si/Er) and silicon-terbium (Si/Tb) thin films using room temperature ionic liquid (RTIL) has been successfully developed. By playing with the electrochemical parameters, the concentration of incorporated rare earth (RE) ions (Er3+ and Tb3+) in the thin films can be tuned. The obtained thin films have been characterized by electron microscopy and composition analysis techniques. The structural quality of the obtained thin films is characterized by a uniform distribution of Si atoms and RE ions throughout the thickness. The study of the optical properties, carried out by photoluminescence (PL) spectroscopy, demonstrates the efficient optical activity of the films with typical Er and Tb luminescence at room temperature depending on the RE content. The deposition method described is a promising strategy for incorporating RE ions in semiconducting thin films to achieve materials for opto-electronic applications.

Heat shock protein 70 regulates platelet integrin activation, granule secretion and aggregation.

Molecular chaperones that support protein quality control, including heat shock protein 70 (Hsp70), participate in diverse aspects of cellular and physiological function. Recent studies have reported roles for specific chaperone activities in blood platelets in maintaining hemostasis; however, the functions of Hsp70 in platelet physiology remain uninvestigated. Here we characterize roles for Hsp70 activity in platelet activation and function. In vitro biochemical, microscopy, flow cytometry, and aggregometry assays of platelet function, as well as ex vivo analyses of platelet aggregate formation in whole blood under shear, were carried out under Hsp70-inhibited conditions. Inhibition of platelet Hsp70 blocked platelet aggregation and granule secretion in response to collagen-related peptide (CRP), which engages the immunoreceptor tyrosine-based activation motif-bearing collagen receptor glycoprotein VI (GPVI)-Fc receptor-γ chain complex. Hsp70 inhibition also reduced platelet integrin-αIIbß3 activation downstream of GPVI, as Hsp70-inhibited platelets showed reduced PAC-1 and fibrinogen binding. Ex vivo, pharmacological inhibition of Hsp70 in human whole blood prevented the formation of platelet aggregates on collagen under shear. Biochemical studies supported a role for Hsp70 in maintaining the assembly of the linker for activation of T cells signalosome, which couples GPVI-initiated signaling to integrin activation, secretion, and platelet function. Together, our results suggest that Hsp70 regulates platelet activation and function by supporting linker for activation of T cells-associated signaling events downstream of platelet GPVI engagement, suggesting a role for Hsp70 in the intracellular organization of signaling systems that mediate platelet secretion, "inside-out" activation of platelet integrin-αIIbß3, platelet-platelet aggregation, and, ultimately, hemostatic plug and thrombus formation.

Electrodeposition of silicon nanotubes at room temperature using ionic liquid.

Electrodeposition inside an insulated nanoporous template using Room Temperature Ionic Liquids (RTILs) has recently been demonstrated as a promising alternative technique for synthesizing silicon nanowires due to low cost ambient growth conditions. An improvement of the method is shown here to produce Si nanotubes. A fine adjustment of electro-chemical parameters influencing ionic diffusion inside the nanopores of the template is demonstrated to preferably lead to the growth of Si nanotubes at the expense of Si nanowires. This study shows that electrodeposition in RTILs is a competitive process to grow high surface to volume ratio nanostructures at low cost and over a large scale. It also indicates a new prospect for the technique to grow and control nanostructures such as radial core-shell nanowires.

Aging effect on the copper sorption on a vineyard soil: column studies and SEM-EDS analysis.

The uptake of copper by a vineyard soil in fixed bed column systems was investigated in order to study the influence of the aging time on the soil retention capacity. The application of copper by means of several additions, as in field conditions, increases the retention capacity of the soil relative to a single one application of the metal. The aging effect is responsible for this phenomenon, since its increase enhances the amount of adsorbed copper. Moreover, aging the soil reduces the amount of available copper during a Ca(NO(3))(2) leaching of the soil columns which suggests a redistribution of a weakly-bound copper fraction to a more strongly-bound fraction. Scanning electron microscopy combined with energy dispersive X-ray spectroscopy (SEM-EDS) indicates that copper is heterogeneously distributed within the soil sample. Nevertheless, copper is preferentially associated with fractions containing Fe and Al atoms.