Synthesis of iron-doped TiO2 nanoparticles by ball-milling process : the influence of process parameters on the structural, optical, magnetic, and photocatalytic properties

Titanium dioxide (TiO2) absorbs only a small fraction of incoming sunlight in the visible region thus limiting its photocatalytic efficiency and concomitant photocatalytic ability. The large-scale application of TiO2 nanoparticles has been limited due to the need of using an ultraviolet excitation source to achieve high photocatalytic activity. The inclusion of foreign chemical elements in the TiO2 lattice can tune its band gap resulting in an absorption edge red-shifted to lower energies enhancing the photocatalytic performance in the visible region of the electromagnetic spectrum. In this research work, TiO2 nanoparticles were doped with iron powder in a planetary ball-milling system using stainless steel balls. The correlation between milling rotation speeds with structural and morphologic characteristics, optical and magnetic properties, and photocatalytic abilities of bare and Fedoped TiO2 powders was studied and discussed.This work was partially financed by FCT-Fundacao para a Ciencia e Tecnologia-under the project PTDC/FIS/120412/2010: "Nanobased concepts for Innovative & Eco-sustainable constructive material's surfaces.

Processes discriminating adaptive and maladaptive Internet use among European adolescents highly engaged online

Today adolescents are highly engaged online. Contrary to common concern, not all highly engaged adolescents develop maladaptive patterns of internet use. The present qualitative study explored the experiences, patterns and impact of use of 124 adolescents (Mage=16.0) reporting signs of internet addictive behaviors. The focus was to discern adaptive and maladaptive use patterns, which promote or interfere with adolescents' development, respectively. Semi-structured individual interviews were conducted in seven European countries (Greece, Spain, Poland, Germany, Romania, Netherlands and Iceland) and qualitatively analyzed using grounded theory. Considerable variability emerged in the way adolescents satisfied their personal needs online and offline, in the experienced impact from high online engagement and functional value ascribed to the internet, and in the self-regulatory processes underlying use. Variability in these discriminating processes was linked to adaptive or maladaptive adolescent internet use patterns. The emerged processes can provide direction for designing prevention and intervention programs promoting adaptive use. © 2014 The Foundation for Professionals in Services for Adolescents

Reactive vasodilation predicts mortality in primary systemic light-chain amyloidosis

RATIONALE: Cardiac involvement and hypotension dominate the prognosis of light-chain amyloidosis (AL). Evidence suggests that there is also peripheral vascular involvement in AL but its prognostic significance is unknown. OBJECTIVE: To evaluate vascular dysfunction in patients with AL as a potential future area of intervention, we assessed the prognostic utility of flow-mediated dilatation (FMD), a marker of vascular reactivity, which is augmented under conditions of hypotension and autonomic dysfunction. METHODS AND RESULTS: We prospectively evaluated 115 newly diagnosed untreated AL patients in whom FMD was measured. FMD in AL patients was significantly higher than age-, sex-and risk factors-matched controls (4.0% versus 2.32%; P=0.006) and comparable with control groups at lower cardiovascular risk (P>0.1). Amyloidosis patients presented increased plasma and exhaled markers of the NO pathway while their FMD significantly correlated with augmented sustained vasodilatation after sympathetic stimulation. Increased FMD (=4.5%) was associated with early mortality (hazard ratio, 4.36; 95% CI, 1.41-13.5; P=0.010) and worse survival (hazard ratio, 2.11; 95% CI, 1.17-3.82; P=0.013), even after adjustment for Mayo stage, nerve involvement and low systolic blood pressure. This finding was confirmed in a temporal validation AL cohort (n=55; hazard ratio, 4.2; 95% CI, 1.45-12.3; P=0.008). FMD provided significant reclassification value over the best prognostic model (continuous Net Reclassification Index, 0.61; P=0.001). Finally, better hematologic response was associated with lower posttreatment FMD. CONCLUSIONS: FMD is relatively increased in AL and independently associated with inferior survival with substantial reclassification value. Reactive vasodilation merits further investigation as a novel risk biomarker in AL. VISUAL OVERVIEW: An online visual overview is available for this article. © 2019 American Heart Association, Inc

Electronic structure and origin of visible-light activity of C-doped cubic In2O3 from first-principles calculations

The origin of the experimentally observed band gap narrowing and red-shift of the adsorption edge of cubic In2O3 induced by C doping has been investigated using density functional theory calculations. We have compared the stability of all these doped systems based on the calculated formation energy as a function of the oxygen chemical potential. The calculated electronic structures show that: (I) at low C concentration, substitutional replacement of O by C could lead to small gap narrowing, owing to C 2p states below the conduction band minimum while interstitial C doping does not induce band gap narrowing; and (II) at high C concentration, C2p states mix well with O 2p states above the valence band, which may account for the experimentally observed red-shift of the absorption edge.Science Foundation IrelandIrish Research Council for Science, Engineering and TechnologyEmbargoed until July 2011 - email from AV 11/02/1

Dual Mechanism of Indium Incorporation into TiO 2

This work considers the effect of indium on defect disorder and semiconducting properties of TiO2 (rutile). It is shown that the electrical conductivity and thermoelectric power data of indium-doped TiO2 can be best described by a dual mechanism of indium incorporation into the TiO2 lattice, including both the titanium sites, leading to the formation of acceptors and interstitial sites, leading to the formation of donors. The concentration ratio of these defects depends on the distance from the surface. The proposed defect disorder model of In-doped TiO2 is considered in terms of the surface layer enriched predominantly in indium located in interstitial sites and the bulk phase involving mainly indium located in the titanium sublattice