Geopolymer composites for potential applications in cultural heritage

A new class of geopolymer composites, as materials alternative to traditional binders, was synthesized and its potentialities as restoration material in Cultural Heritage has been explored. This material has been prepared through a co-reticulation reaction in mild conditions of a metakaolin-based geopolymer inorganic matrix and a commercial epoxy resin. The freshly prepared slurry displays a consistency, workability and thixotropic behavior that make it suitable to be spread on different substrates in restoration, repair and reinforcement actions, even on walls and ceilings. Applicability and compatibility tests on tuff and concrete substrates were carried out and the microstructure of the samples in correspondence of the transition zone was analyzed by means of scanning electron microscope (SEM) observations and energy dispersive spectroscopy (EDS) mapping. Our studies pointed out the formation of a continuous phase between the geopolymer composite and tuff and concrete substrates, highlighting a high compatibility of the geopolymer binder with different kinds of materials. These features indicate a large potential for applications of these materials in Cultural Heritage

Synthesis of highly regioregular poly[3-(4-alkoxyphenyl)-thiophene]s by oxidative catalysis using copper complexes

A novel, easy, and cost-effective synthetic procedure is reported for the production of very highly regioregular poly[3-(4-alkoxyphenyl)thiophene]s by means of oxidative coupling. Four copper complexes were synthesized and used as catalysts to obtain polymers with higher regioregularity compared to the previous oxidative coupling methodologies reported in the literature and similar to that obtained by McCullough and Rieke methods in the synthesis of poly-3-alkylthiophenes. The regioregularity of the synthesized polymers was investigated by UV-Visible characterization on polymer thin films and 1H NMR analysis. The remarkable potentialities of these polymers have emerged from field-effect transistor mobility measurements operated on devices with bottom-contact configuration and hexamethyldisilazane-treated SiO 2 gate dielectric, showing a well-defined p-type field-effect response and maximum mobility values in air higher than 10-4 cm 2 V-1 s-1. © 2013 Wiley Periodicals, Inc

High nonlinear optical response in 4-chlorothiazole-based azo dyes

Four azo dyes showing high nonlinear optical properties were prepared, based on a 4-chlorothiazole azo moiety functionalized with strong acceptor groups and/or further donor/acceptor groups along the conjugated backbone. The effects of the acceptors as well as the lateral donor/acceptor groups upon absorption properties, thermal stability and second order nonlinear optical activity were evaluated. © 2010 Elsevier Ltd. All rights reserved

Photopolymer-based volume holographic optical elements: design and possible applications

In this paper, Volume Holographic Optical Elements (V-HOEs), such as holographic gratings and spherical lenses, are designed and fabricated by using a prototype of photopolymer. The recording process of V-HOEs and their appropriate characterization are described. Moreover, V-HOEs possible applications as solar concentrator are investigated and results are discussed. Finally, a system that allows passive solar tracking is proposed and preliminary results are reported

Perylene diimides functionalized with N-thiadiazole substituents: Synthesis and electronic properties in OFET devices

Two new perylene diimide derivatives N,N′-bis(5-tridecyl-1,3,4- thiadiazol-2-yl)perylene-3,4,9,10-tetracarboxylic 3,4:9,10-diimide (PDI-T1) and N,N′-bis[5-(1-hexyl)nonyl-1,3,4-thiadiazol-2-yl]perylene-3,4,9, 10-tetracarboxylic 3,4:9,10-diimide (PDI-T2), achieved by functionalizing the basic perylene molecular core at imide nitrogen with 1,3,4-thiadiazole rings, have been synthesized. Both these compounds make possible the fabrication of n-type organic thin-film transistors able to work in air, even when bare SiO2 surfaces are utilized as gate dielectric. As active channels of transistors in the bottom-contact bottom-gate configuration, PDI-T1 evaporated films exhibited a maximum mobility of 0.016 cm2/V s in vacuum. For evaporated PDI-T2 films, instead, mobility values were found to be more than one order of magnitude lower, because of their reduced degree of crystalline order. However, PDI-T2 films can be also deposited by solution techniques and field-effect transistors were fabricated by spin-coating, displaying mobility values ranging between 10-6 and 10-5 cm2/V s. Similar to what previously found for other perylene diimide derivatives, our experimental work also demonstrates that the electrical response of both PDI-T1 and PDI-T2 transistors under ambient conditions can be improved by increasing the level of hydrophobicity of the dielectric surface. © 2012 Elsevier B.V. All rights reserved

Poor outcome for patients with gastric cancer and lung metastases treated with ramucirumab and paclitaxel

The aim of this report is to investigate the activity of ramucirumab in combination with paclitaxel in patients with metastatic gastric cancer (GC) and lung metastases. We retrospectively reviewed clinical data from patients with GC treated in second line with ramucirumab and paclitaxel according to the presence or not of lung metastases. Thirty-one patients were eligible. Five (16.1%) patients had lung metastases. The median progression-free survival was 156 days in patients without lung metastases compared with 54 days in patients with lung metastases. The median survival also showed a trend in favour of patients without lung metastases. Despite the small number of patients and the retrospective nature of the data, our analysis showed relatively poor efficacy of ramucirumab plus paclitaxel as a second-line treatment in patients with lung metastases from GC. Further studies are required to evaluate novel treatments in this subset of patients

Fluorescence and Morphology of Self-Assembled Nucleobases and Their Diphenylalanine Hybrid Aggregates

Studies carried out in recent decades have revealed that the ability to self-assemble is a widespread property among biomolecules. Small nucleic acid moieties or very short peptides are able to generate intricate assemblies endowed with remarkable structural and spectroscopic properties. Herein, the structural/spectroscopic characterization of aggregates formed by nucleobases and peptide nucleic acid (PNA)-peptide conjugates are reported. At high concentration, all studied nucleobases form aggregates characterized by previously unreported fluorescence properties. The conjugation of these bases, as PNA derivatives, to the dipeptide Phe-Phe leads to the formation of novel hybrid assemblies, which are characterized by an amyloid-like association of the monomers. Although these compounds share the same basic cross-\u3b2 motif, the nature and number of PNA units have an important impact on both the level of structural order and the intrinsic fluorescence of the self-assembled nanostructure