Increasing the structural and compositional diversity of ion-track templated 1D nanostructures through multistep etching, plastic deformation, and deposition.

Ion-track etching represents a highly versatile way of introducing artificial pores with diameters down into the nm-regime into polymers, which offers considerable synthetic flexibility in template-assisted nanofabrication schemes. While the mechanistic foundations of ion-track technology are well understood, its potential for creating structurally and compositionally complex nano-architectures is far from being fully tapped. In this study, we showcase different strategies to expand the synthetic repertoire of ion-track membrane templating by creating several new 1D nanostructures, namely metal nanotubes of elliptical cross-section, funnel-shaped nanotubes optionally overcoated with titania or nickel nanospike layers, and concentrical as well as stacked metal nanotube-nanowire heterostructures. These nano-architectures are obtained solely by applying different wet-chemical deposition methods (electroless plating, electrodeposition, and chemical bath deposition) to ion-track etched polycarbonate templates, whose pore geometry is modified through plastic deformation, consecutive etching steps under differing conditions, and etching steps intermitted by spatially confined deposition, providing new motifs for nanoscale replication.

Mortality and morbidity in different immunization protocols for experimental autoimmune myocarditis in rats.

AIM: We aimed to investigate the histological and clinical presentations of experimental autoimmune myocarditis (EAM) induced by different immunization schemes. METHODS: Male young Lewis rats were divided into five groups immunized by porcine myocardial myosin: subcutaneously (SC) 2 mg (in two 1-mg doses on day 0 and 7), 0 mg (sham group) subcutaneously into rear footpads (RF), 0.25 mg RF, 0.5 mg RF or 1 mg RF (all RF once on day 0). On day 21, left ventricular (LV) function was assessed by cardiac magnetic resonance imaging and cardiac catheterization. The type and degree of myocardial inflammatory infiltrates were determined by conventional histology and immunohistochemistry. RESULTS: In the SC immunized rats and in the RF sham group, we observed 0% mortality, while in the actively RF immunized rats, mortality was 20, 20 and 44% for the 0.25 mg, 0.5 mg and 1 mg myosin doses respectively. Morbidity as defined by inflammatory infiltrates on haematoxylin and eosin (HE) staining was 22% in the SC immunized rats, 0% in the RF sham group and 100% in all actively RF immunized groups. We observed augmented relative ventricle weight and spleen weight, increased LV end-diastolic pressure, reduced LV developed pressure and reduced LV ejection fraction in all with myosin-immunized RF groups without any systematic dose effect. CONCLUSION: Subcutaneous immunization to the neck and flanks did not induce a reproducible EAM, while RF myosin administration reliably led to EAM. Lower myosin doses seem to induce the complete histological and clinical picture of EAM while being associated with lower mortality, non-specific symptoms and animal distress.

Thermal stability of electrodeposited platinum nanowires and morphological transformations at elevated temperatures.

Pt nanowires were prepared by template electrodeposition using ion track etched polymer membranes and analysed with respect to their thermal stability. Driven by Rayleigh instability, the polycrystalline Pt nanostructures experienced structural transformations and finally fragmented into linear chains of nanospheres at temperatures much below the melting point of bulk Pt. Morphological changes were systematically studied by electron microscopy and compared with previously reported results on other metal nanowires and theoretical predictions. In addition, nanowires could readily be interconnected to two-dimensional assemblies by taking advantage of the rapid diffusion processes. This study will help to predict the durability of integrated nanowires and contributes to the understanding of thermal-induced transformations for polycrystalline nanowires.