Electronic phase diagram of La1.875_{1.875}Ba0.125−x_{0.125-x}Srx_xCuO4_4

We performed systematic measurements of magnetic susceptibility on single crystals of La$_{1.875}$Ba$_{0.125-x}$Sr$_x$CuO$_4$. The dependence of the superconducting transition temperature on Sr-concentration demonstrates a step-like pattern upon doping at {\it x}$\sim$0.08 as the crystal structure changes from low-temperature tetragonal (LTT) to low-temperature orthorhombic (LTO) phase at low temperature. Upon cooling, an anomalous upturn in the susceptibility was observed at the structural phase transition between the LTT-LTO phases under the magnetic field parallel to {\it c}-axis.Comment: 6 pages, 4 figures, Proceeding paper of the Stripes2000 conference in Roma, Ital

Colloidal Assemblies of Oriented Maghemite Nanocrystals and their NMR Relaxometric Properties

Elevated-temperature polyol-based colloidal-chemistry approach allows for the development of size-tunable (50 and 86 nm) assemblies of maghemite iso-oriented nanocrystals, with enhanced magnetization. 1H-Nuclear Magnetic Resonance (NMR) relaxometric experiments show that the ferrimagnetic cluster-like colloidal entities exhibit a remarkable enhancement (4 to 5 times) in the transverse relaxivity, if compared to that of the superparamagnetic contrast agent Endorem, over an extended frequency range (1-60 MHz). The marked increase of the transverse relaxivity r2 at a clinical magnetic field strength (1.41 T), which is 405.1 and 508.3 mM-1 s-1 for small and large assemblies respectively, allows to relate the observed response to the raised intra-aggregate magnetic material volume fraction. Furthermore, cell tests with murine fibroblast culture medium confirmed the cell viability in presence of the clusters. We discuss the NMR dispersion profiles on the basis of relaxivity models to highlight the magneto-structural characteristics of the materials for improved T2-weighted magnetic resonance images.Comment: Includes supporting informatio

Social Media Battles: their Impact during the 2014 Greek Municipal Elections

The purpose of this study is to examine the use of social media such as Facebook, Twitter, and YouTube by candidates running for the 2014 Greek Municipal Elections by addressing the following questions: (1) which factors affect social media adoption by municipal candidates?, and (2) whether social media usage along with the popularity of candidates' social media pages influence candidates' vote share. Results indicate that social media are not very popular campaigning tools among municipal candidates in Greece. This implies that Greek candidates still rely on traditional ways to lure their voters. Furthermore, findings reveal that candidates running in large municipalities are more likely to utilize social media (i.e., Facebook, Twitter, and YouTube) as means of political marketing. In addition, challengers seem to prefer Facebook and Twitter as campaign tools while males tend to focus on YouTube to attract voters. Despite the low adoption rate, results suggest that candidates who made use of social media won more votes compared to candidates who were not social media users. Moreover, it was found that a candidate's Facebook page and YouTube channel popularity are good indicators of the candidate's vote share

P 419 Comparison of tight junctions permeability and modulation in iris pigment epithelium and retinal pigment epithelium in vitro

Amb una superfície: 0,61 ha, de basalt i aigua nebulitzada.Barragán, Pedro (dissenyador)Gran pla general de El Volcà,conegut com la Carbonera. El carbó calent era mullat per aigua subterrània i desprenia vapor. Actualment està inactiu. Destaquen el pg. Josep Carner amb el monument a Colom i els edificis de Capitania i Duana

Magnetic versus nonmagnetic doping effects on the magnetic ordering in the Haldane chain compound PbNi2V2O8

A study of an impurity driven phase-transition into a magnetically ordered state in the spin-liquid Haldane chain compound PbNi2V2O8 is presented. Both, macroscopic magnetization as well as 51V nuclear magnetic resonance (NMR) measurements reveal that the spin nature of dopants has a crucial role in determining the stability of the induced long-range magnetic order. In the case of nonmagnetic (Mg2+) doping on Ni2+ spin sites (S=1) a metamagnetic transition is observed in relatively low magnetic fields. On the other hand, the magnetic order in magnetically (Co2+) doped compounds survives at much higher magnetic fields and temperatures, which is attributed to a significant anisotropic impurity-host magnetic interaction. The NMR measurements confirm the predicted staggered nature of impurity-liberated spin degrees of freedom, which are responsible for the magnetic ordering. In addition, differences in the broadening of the NMR spectra and the increase of nuclear spin-lattice relaxation in doped samples, indicate a diverse nature of electron spin correlations in magnetically and nonmagnetically doped samples, which begin developing at rather high temperatures with respect to the antiferromagnetic phase transition.Comment: 10 pages, 7 figure

Engineering the Catalytic Properties of HZSM5 by Cobalt Modification and Post-synthetic Hierarchical Porosity Development

Hierarchical zeolites have been identified as special catalytic materials with improved catalytic properties. In this study, hierarchical bifunctional ZSM5 based catalysts were prepared by desilication for controlled mesoporosity development and have been modified by Co doping. Their performance in the catalytic pyrolysis of oak in a lab scale reactor was evaluated. Desilicated counterparts were proven more active in deoxygenation of bio oil, while carbon deposition on the catalysts reduced compared to non-desilicated counterparts. Increased Lewis acidity favors decarboxylation reactions, while higher olefins as well as PAH content indicate easier diffusion within and from the porous network and interactions in the mesopores. The conversion of bulky lignin molecules (alkoxy phenols) is enhanced by the mesopores, while acidity is of secondary importance. Coke deposition inside the pores is more profound in the desilicated catalysts due to larger pore size. Carbon deposition on the catalysts is reduced in the following order: HZSM5 > Co/HZSM5 > Ds-HZSM5 > Co/Ds-HZSM5. GC–MS characterization of the CH2Cl2 soluble coke indicated that for the desilicated counterparts the main coke precursors are the bulky lignin molecules which are partially deoxygenated