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We present and discuss the role of nanoparticles size and stoichiometry over the local atomic environment of nanostructured VOx films. The samples have been characterized in situ using X-ray absorption near-edge structure (XANES) spectroscopy identifying the stoichiometry-dependent fingerprints of disordered atomic arrangement. In vanadium oxides, the ligand atoms arrange according to a distorted octahedral geometry depending on the oxidation state, e.g. trigonal distortion in V2O3 and tetragonal distortion in bulk VO2. We demonstrate, taking VO2 as a case study, that as a consequence of the nanometric size of the nanoparticles, the original ligands symmetry of the bulk is broken resulting in the coexistence of a continuum of distorted atomic conformations. The resulting modulation of the electronic structure of the nanostructured VOx as a function of the oxygen content reveals a stoichiometry-dependent increase of disorder in the ligands matrix. This work shows the possibility to produce VOx nanostructured films accessing new disordered phases and provides a unique tool to investigate the complex matter. [ABSTRACT FROM AUTHOR]

X-ray absorption spectroscopy was used to study the evolution of the local structure induced by nickel doping in LiFe $$_{1-x}$$ Ni $$_{x}$$ PO $$_{4}$$ solid solutions, functional materials for Li-ion cells. Samples with increasing Ni content ( x = 0, 0.03, 0.05, 0.10, 0.15) were measured and analyzed by extended X-ray absorption fine structure (EXAFS) at both Ni and Fe K-edges. Experiments were carried out at room temperature and at various temperatures in the 23-300 K range. Fe-O and Ni-O nearest neighbor distances were accurately measured by EXAFS double-edge data-analysis. The Ni and Fe octahedral sites have been found to be largely distorted in the solid solutions, with two atoms at longer distances. Mean square relative displacements of neighboring atoms (O and P) are found to be larger indicating the presence of an increased level of configurational disorder. EXAFS shows that the basic connectivity structure between Fe/Ni- and P-based polyhedra is preserved, but differences in local geometry and distance distributions are found. Possible connections among the presence of a distribution of distorted octahedra of different size in the structure and different electrochemical performances of the material as a function of doping are briefly discussed. [ABSTRACT FROM AUTHOR]

Silicon nanowires fabricated by metal-assisted chemical etching can present low porosity and a rough surface depending on the doping level of the original silicon wafer. In this case, wiring of silicon nanowires may represent a challenging task. We investigated two different approaches to realize the electrical contacts in order to enable electrical measurement on a rough silicon nanowire device: we compared FIB-assisted platinum deposition for the fabrication of electrical contact with EBL technique. [ABSTRACT FROM AUTHOR]

A Schiff base, N, N′-(3,4-dithiahexane-1,6-diyl)bis(5-methylsalicylideneimine), was synthesized and characterized by X-ray crystallography. Dimeric complexes of nickel(II), palladium(II), and vanadium(IV) were synthesized by the reactions of the Schiff base with nickel(II) acetate, palladium(II) acetate, and vanadyl acetylacetonate in 1:1 molar ratio. In all three complexes, the thiol group was deprotonated and coordinated to the metal. The X-ray structure of the Schiff base showed that in the crystalline form, the SH groups were oxidized to the corresponding disulfide. In the dimeric complexes, coordination took place through the azomethine nitrogen, enolic oxygen, and sulfur atoms. The metal-to-ligand ratio was 1:1, and molar conductance data revealed that the metal complexes were nonelectrolytes. The free Schiff base and its complexes showed photoluminescence in methanol at room temperature. The redox behavior of the compounds was studied by cyclic voltammetry in DMF, which showed both quasi-reversible and irreversible processes. The interaction of the complexes with DNA was investigated by electronic absorption spectroscopy. [ABSTRACT FROM AUTHOR]

In order to improve the mechanical properties and decrease the manufacturing costs of traditional polymer concrete, a new concrete mix is presented, where fine silica sand is used instead of common large and small aggregates. In addition, to decrease manufacturing costs, a polyester resin is employed instead of epoxy matrix. By performing compression and three-point bending tests, it was found that the new polymer concrete had a higher compression strength than the traditional polymer concrete and a similar bending strength. Also, a two-phase micromechanical model was used to analytically estimate the compressive strength of the new material, and a rather good agreement between experimental data and theoretical calculations was found to exist. [ABSTRACT FROM AUTHOR]

The article presents a study that evaluates prevalence and control of diabetes in urban area of north of Iran. It informs that the study was done on a sample of urban population from Iran that were subjected to biochemical testing using their blood samples and further the data analysis was carried out using the data mining software SPSS. The study found that prevalence of diabetes is higher in urban population in north of Iran.

Cardiovascular disease is the first cause of death among older persons worldwide. Therefore, assessing the characteristics of cardiovascular risk factors in the elderly should become a priority especially in populations with different dietary and cultural characteristics. Determining the gender difference in the prevalence of cardiovascular risk factors among elderly population in northern Iran. This is a cross sectional study in a representative sample of urban population from14 cities in northern Iran. Subjects 15 year-old and older were interviewed and examined by a trained research team. Blood samples were drawn for biochemical testing. Data analysis was done using SPSS 14 software and χ test was used. For the aims of this study only data obtained from subjects 60 year old and older were included. From 2282 subjects in the whole study population, 291 (12.7 %) subjects were older than 60 years. From them 51.5 % were male, 42.1 % were illiterate and 9 % had academic education (more than 12th grade). 27.4 % males and 2.1 % females were smokers ( ρ < 0.0001). Hypertension was reported in 54.9 % males and 81 % females ( ρ < 0.0001). 50.7 % males and 72.1 % females had dyslipidemia ( ρ < 0.0001), 24 % males and 35.5 % females were diabetic ( ρ < 0.04). Only 48.2 % males and 22.6 % females had normal weight with the rest being either overweight or obese ( ρ < 0.0001). In contrast to other demographic studies, and with the exception of smoking, the prevalence of cardiovascular risk factors in Iran is higher in older women in comparison to men. These findings indicate that a comprehensive national program for management of cardiovascular diseases in the elderly, with emphasis on older women, is urgently needed. [ABSTRACT FROM AUTHOR]

This study is focused on twenty trace elements (Ag, Ba, Bi, Cd, Co, Cr, Cs, Cu, Ga, In, Mn, Mo, Pb, Rb, Sb, Sn, Sr, Ti, V, Zn) accumulation in muscles of five sturgeon species (Acipenser guldenstaedti, A. persicus, A. nudiventris, A. stellatusandHuso huso) from the southern part of the Caspian Sea. Moreover the relationships between some biological characteristics and the levels of the selected elements as well as inter-elemental relationships were assessed. The samples (10 specimens for each the five species) were collected from two important sturgeon fishery zones located in the Iranian part of the Sea in 2002. Concentrations of the elements were determined using ICPMS. Only in the case of Cs could significant differences between two selected sampling areas be detected. There were significant differences in levels of Co, Ga, Rb, Sn, Ti, Pb and Bi in muscles of the species. Only in the case of Cd weight related differences among the species were found. The significant length dependent relationships were observed for Ga and Ba. Patterns of elements accumulation were assessed by statistical methods and compared to the other researches. In all the cases, the amounts of toxic trace elements (Cd, Cu, Pb and Zn) were markedly below the international guidelines for human consumption. [ABSTRACT FROM AUTHOR]

Ultrafast optical reflectivity measurements of silicon, germanium, and gallium arsenide have been carried out using an advanced set-up providing intense subpicosecond pulses (35 fs FWHM, λ = 400 nm) as a pump and broadband 340–780 nm ultrafast pulses as a white supercontinuum probe. Measurements have been performed for selected pump fluence conditions below the damage thresholds, that were carefully characterized. The obtained fluence damage thresholds are 30, 20.8, 9.6 mJ/ cm 2 for Si, Ge and GaAs respectively. Ultrafast reflectivity patterns show clear differences in the Si, Ge, and GaAs trends both for the wavelength and time dependences. Important changes were observed near the wavelength regions corresponding to the E 1 , E 1 + Δ singularities in the joint density of states, so related to the peculiar band structure of the three systems. For Ge, ultrafast reflectivity spectra were also collected at low temperature (down to 80 K) showing a shift of the characteristic doublet peak around 2.23 eV and a reduction of the recovery times. [ABSTRACT FROM AUTHOR]