Organophosphonate biofunctionalization of diamond electrodes.

The modification of the diamond surface with organic molecules is a crucial aspect to be considered for any bioapplication of this material. There is great interest in broadening the range of linker molecules that can be covalently bound to the diamond surface. In the case of protein immobilization, the hydropathicity of the surface has a major influence on the protein conformation and, thus, on the functionality of proteins immobilized at surfaces. For electrochemical applications, particular attention has to be devoted to avoid that the charge transfer between the electrode and the redox center embedded in the protein is hindered by a thick insulating linker layer. This paper reports on the grafting of 6-phosphonohexanoic acid on OH-terminated diamond surfaces, serving as linkers to tether electroactive proteins onto diamond surfaces. X-ray photoelectron spectroscopy (XPS) confirms the formation of a stable layer on the surface. The charge transfer between electroactive molecules and the substrate is studied by electrochemical characterization of the redox activity of aminomethylferrocene and cytochrome c covalently bound to the substrate through this linker. Our work demonstrates that OH-terminated diamond functionalized with 6-phosphonohexanoic acid is a suitable platform to interface redox-proteins, which are fundamental building blocks for many bioelectronics applications.

Properties of uniform diameter InN nanowires obtained under Si doping.

High quality, well-separated, homogeneous sizes and high aspect ratio Si-doped InN nanowires (NWs) were grown by catalyst-free molecular beam epitaxy (MBE) after optimization of the growth conditions. To this end, statistical analysis of NW density and size distribution was performed. The high crystal quality and smooth NW surfaces were observed by high resolution transmission electron microscopy. Spectral photoluminescence has shown the increase of the band filling effect with Si flux, indicating successful n-type doping. A Raman LO scattering mode appears with a pronounced low energy tail, also reported for highly doped InN films.

[Ventricular hypoplasia in congenital heart diseases]. / Le ipoplasie ventricolari nelle cardiopatie congenite.

Twenty-seven cases of autopsy showing hypoplasia of one of the ventricular cavities, prevalently the left, were selected from a series of 103 congenital cardiopathies (1979-1990). In 9 cases ventricular hypoplasia formed part of complex malformative syndromes with a well-known physiognomy: a further 18 cases showed a complete (9 cases) or incomplete (9 cases) hypoplastic heart syndrome. Subjects were prevalently female and the presence of other malformations indicating a genetic dysfunction was less evident than in other cardiopathies. The different pathogenetic hypotheses are discussed in the light of macro- and microscopic morphological factors, of which the most plausible is that involving an anomalous position or orientation of the musculo-membranous folds which give rise to the septation system of the various metamers of the cardiac tube.

[Cardiac malformations with septal defects. Apropos of a case of biloculate heart with transposition and aortic atresia]. / Le malformazioni cardiache con difetti settali. A proposito di un caso di cuore biloculato con trasposizione ed atresia aortica.

The Authors describe a case of uniatrial univentricular heart with a right transposition and atresia of the aorta. This case forms part of an autoptic series of 74 congenital cardiopathies with defects of the septal system: monometameric (52 cases), polymetameric (22 cases), and limited (66 cases) or broad DIA, DIV or FAP types (8 cases). Having outlined the correlations between the type of defect and the complex morphogenetic events, whose close integration leads to a continuous septal system, the Authors focus their attention on the common associations between septal defects and other cardio-vascular anomalies (66 cases). The analysis of findings supports hypothesis that many of these are due to alterations in the position and direction of individual septal buds are should be seen against the overall background of septal pathology. Under these circumstances the pathogenetic importance of alterations of the complex movements presented by the cardiac type during the course of septal development and, to an event greater extent, possible alterations of the embryonal hematic flow are underlined.