Ultra narrow AuPd and Al wires

In this letter we discuss a novel and versatile template technique aimed to the fabrication of sub-10 nm wide wires. Using this technique, we have successfully measured AuPd wires, 12 nm wide and as long as 20 $\mu$m. Even materials that form a strong superficial oxide, and thus not suited to be used in combination with other techniques, can be successfully employed. In particular we have measured Al wires, with lateral width smaller or comparable to 10 nm, and length exceeding 10 $\mu$m.Comment: 4 pages, 4 figures. Pubblished in APL 86, 172501 (2005). Added erratum and revised Fig.

Tris(1,3-dichloro-2-propyl) phosphate disrupts dorsoventral patterning in zebrafish embryos.

Tris(1,3-dichloro-2-propyl) phosphate (TDCIPP) is a high-production volume organophosphate flame retardant widely used within the United States. Within zebrafish, initiation of TDCIPP exposure at 0.75 h post-fertilization (hpf) results in genome-wide alterations in methylation during cleavage (2 hpf) as well as epiboly delay or arrest (at higher concentrations) during late-blastula and early-gastrula (4-6 hpf). To determine whether these TDCIPP-induced effects were associated with impacts on the transcriptome, embryos were exposed to vehicle (0.1% DMSO) or 2 µM TDCIPP from 0.75 hpf to 6 hpf, and total RNA was extracted from triplicate embryo pools per treatment and hybridized onto duplicate Affymetrix Zebrafish Gene 1.0 ST Arrays per RNA sample. Based on transcriptome-wide profiling, TDCIPP resulted in a significant impact on biological processes involved in dorsoventral patterning and bone morphogenetic protein (BMP) signaling. Consistent with these responses, TDCIPP exposure also resulted in strongly dorsalized embryos by 24 hpf-a phenotype that mimicked the effects of dorsomorphin, a potent and selective BMP inhibitor. Moreover, the majority of dorsalized embryos were preceded by epiboly arrest at 6 hpf. Our microarray data also revealed that the expression of sizzled (szl)-a gene encoding a secreted Frizzled-related protein that limits BMP signaling-was significantly decreased by nearly 4-fold at 6 hpf. Therefore, we used a splice-blocking morpholino to test the hypothesis that knockdown of szl phenocopies TDCIPP-induced delays in epiboly progression. Interestingly, contrary to our hypothesis, injection of szl MOs did not affect epiboly progression but, similar to chordin (chd) morphants, resulted in mildly ventralized embryos by 24 hpf. Overall, our findings suggest that TDCIPP-induced epiboly delay may not be driven by decreased szl expression, and that TDCIPP-induced dorsalization may-similar to dorsomorphin-be due to interference with BMP signaling during early zebrafish development

The 5, 10 methylenetetrahydrofolate reductase C677T mutation and risk of fetal loss: a case series and review of the literature

<p>Abstract</p> <p>Background</p> <p>The true relationship between methylenetetrahydrofolate reductase C677T homozygosity and risk of recurrent spontaneous abortion is unknown, and it is unclear if women with these mutations should be anticoagulated during pregnancy.</p> <p>Objectives</p> <p>We report a series of 8 patients with this issue and review the current literature.</p> <p>Methods</p> <p>8 patients (3 of whom were actively pregnant) were referred with histories of spontaneous fetal loss; hypercoaguability work-ups revealed each were homozygous for the MTHFR C677T mutation without other thrombophilias.</p> <p>Results</p> <p>In the 3 women who have conceived, treatment with LMW heparin during pregnancy led to two full-term births and one additional pregnancy without complication. For the 5 who have not, we recommended treatment with LMW heparin upon conception.</p> <p>Conclusion</p> <p>We provide evidence to support the relationship between MTHFR C677T mutations and recurrent fetal loss, and to suggest that anticoagulation of these patients during pregnancy can lead to a successful pregnancy outcome.</p

TOWARDS THE PHOTOCATALYTIC PRODUCTION OF SOLAR FUELS - NANOSTRUCTURED TITANIUM DIOXIDE FOR PHOTOCATALYSIS &amp; PHOTO-ELECTROCHEMISTRY

In spite of many efforts given during the last decades to find new alternative photocatalytic materials, titanium dioxide (TiO2) still represents the most widely employed semiconductor for photocatalytic applications, being photoactive, cheap, easily available, non-toxic, inert and, most of all, chemically stable. However, although exhibiting a powerful combination of extraordinary and attractive physico-chemical properties, it suffers from some issues, common to all semiconductors, related to the dynamic of the charge carriers. Precisely, trapping and recombination of valence band holes and conduction band electrons occur at a certain extent, anyway resulting in a drop of the process efficiency. Therefore, in view of limiting these detrimental phenomena, the charge transfer and the electric conductivity of a semiconductor can be enhanced, thus leading to an overall improvement of the photocatalyst performance. In the first part of the work, homemade and commercial TiO2 powders were studied as photocatalysts for different applications, including the liquid-phase photocatalytic oxidation of ammonia and formic acid, and the H2 production through photocatalytic reforming of water-methanol vapors. In this context, a dopant (NH4F) was used during the sol-gel synthesis of the semiconductor to stabilize the formation of the TiO2 anatase phase (typically more active than rutile TiO2 because of its higher electron mobility), especially when crystallization of the amorphous oxides was performed at high temperature (700 \u2daC). Furthermore, the effects induced by noble metal nanoparticles deposition on TiO2 anatase powders were also investigated. In situ electron spin resonance spectroscopy was employed to determine the amount of electrons and holes trapping centers formed under irradiation, in the absence and in the presence of noble metal co-catalysts at the surface of TiO2, hence assessing also the ability of Au and Pt nanoparticles in trapping conduction band electrons. The results were of great usefulness not only to interpret the different H2 production rates but also to understand some mechanistic aspects concerning the selectivity towards the different oxidation products in the methanol photo-steam reforming reaction. In the second part of the work, the nanostructuring of the semiconductor was explored by fabricating TiO2 nanotube arrays through electrochemical anodization. The anodic oxides were employed for both photocatalytic and photo-electrochemical H2 production. In view of large-scale application, the anodization approach was studied on wide Ti substrate surfaces, in order to assess the feasibility of the scale up. Moreover, TiO2 nanotubes were also grown on Ti-based alloys. When fabricating the nanotubes under optimized conditions on Ti-Ta alloys, highly photoactive Ta-doped TiO2 nanotubes were obtained, exhibiting superior water splitting ability. When anodizing Ti-Au alloys, the TiO2 nanotubes resulted decorated with Au nanoclusters. These Au-decorated TiO2 nanotube arrays were used as efficient photocatalyst for H2 production from ethanol-water solutions. Finally, the fabrication of short TiO2 nanotube layers exhibiting an unprecedented level of self-ordering was achieved through an innovative anodization approach. The highly ordered topography allowed the subsequent self-ordering dewetting of Au, leading to Au nanoparticles of controllable size and distribution. These short, Au nanoparticles-filled TiO2 nanotubes exhibited advanced photoactivity ascribed to their reaction vessel-like geometry, fulfilling the requirements in terms of solid state charge carriers diffusion and liquid phase diffusion of oxidizing radicals

Odd and Even Lidstone-type polynomial sequences. Part 1: basic topics

Abstract Two new general classes of polynomial sequences called respectively odd and even Lidstone-type polynomials are considered. These classes include classic Lidstone polynomials of first and second kind. Some characterizations of the two classes are given, including matrix form, conjugate sequences, generating function, recurrence relations, and determinant forms. Some examples are presented and some applications are sketched