Sorption Thermodynamics of CO2, H2O, and CH3OH in a Glassy Polyetherimide: A Molecular Perspective

In this paper, the sorption thermodynamics of low-molecular-weight penetrants in a glassy polyetherimide, endowed with specific interactions, is addressed by combining an experimental approach based on vibrational spectroscopy with thermodynamics modeling. This modeling approach is based on the extension of equilibrium theories to the out-of-equilibrium glassy state. Specific interactions are accounted for in the framework of a compressible lattice fluid theory. In particular, the sorption of carbon dioxide, water, and methanol is illustrated, exploiting the wealth of information gathered at a molecular level from Fourier-transform infrared (FTIR) spectroscopy to tailor thermodynamics modeling. The investigated penetrants display a different interacting characteristic with respect to the polymer substrate, which reflects itself in the sorption thermodynamics. For the specific case of water, the outcomes from molecular dynamics simulations are compared with the results of the present analysis

Concept, prototyping and application of a tensioning system for FRP ties into masonry structures

The present paper deals with concept, prototyping and application of a tensioning system for FRP ties into masonry structures. The proposed system, based on the use of FRP strands instead of traditional steel ties, has the aim to produce a compression stress state on masonry walls where it is applied. Given the objective difficulty in tensioning a FRP strand, it has been necessary to both characterize and prototype a suitable connection system between the strand and the pulling system. The experimental phase concerned both the manufacturing of the pulling system and the study of used materials, as well as the characterization of the impregnation technology of FRP ties. The above described system has been produced and used in the framework of the structural retrofitting of the “Real Albergo dei Poveri” building in Naples

DAMEWARE - Data Mining & Exploration Web Application Resource

Astronomy is undergoing through a methodological revolution triggered by an unprecedented wealth of complex and accurate data. DAMEWARE (DAta Mining & Exploration Web Application and REsource) is a general purpose, Web-based, Virtual Observatory compliant, distributed data mining framework specialized in massive data sets exploration with machine learning methods. We present the DAMEWARE (DAta Mining & Exploration Web Application REsource) which allows the scientific community to perform data mining and exploratory experiments on massive data sets, by using a simple web browser. DAMEWARE offers several tools which can be seen as working environments where to choose data analysis functionalities such as clustering, classification, regression, feature extraction etc., together with models and algorithms.Comment: User Manual of the DAMEWARE Web Application, 51 page

Plasmonics in heavily-doped semiconductor nanocrystals

Heavily-doped semiconductor nanocrystals characterized by a tunable plasmonic band have been gaining increasing attention recently. Herein, we introduce this type of materials focusing on their structural and photo physical properties. Beside their continuous-wave plasmonic response, depicted both theoretically and experimentally, we also review recent results on their transient, ultrafast response. This was successfully interpreted by adapting models of the ultrafast response of gold nanoparticles.Comment: 20 pages review paper, 15 figure

Time evolution of restless legs syndrome in haemodialysis patients

Abstract Background Restless legs syndrome (RLS) is characterized by an urge to move the extremities, accompanied by paraesthesiae, in the evening and at night. Uraemic RLS, a type of secondary RLS, occurs commonly in chronic kidney disease and end-stage renal disease. Progression of uraemic RLS over time is unclear. Therefore we investigated the prevalence, progression over time, risk factors and impact on survival of uraemic RLS in a cohort of dialysis patients. Methods We reviewed at the 7-year follow-up a cohort of haemodialysis (HD) patients we had previously investigated for RLS, through interviews, validated questionnaires and analysis of demographic and clinical data. Results At the 7-year follow-up, RLS was present in 16% of patients, with a persistence rate of 33%. A correlation was obtained between RLS and older age, diabetes, low albumin and low body mass index. RLS was associated with reduced overall survival (median survival of 3.3 versus 3.7 years), particularly with the continuous form of RLS (1.61 years). There was a higher incidence of myocardial infarction and peripheral vascular disease, although not reaching statistical significance. RLS patients had absolute higher scores in all quality of life domains. A large majority of study patients (96%) reported being symptom-free within a few days or weeks following kidney transplantation. Conclusions The development of RLS, especially the continuous form, in patients undergoing HD has important consequences associated with decreased survival. Our results indicated an association between uraemic RLS and ageing, diabetes and malnutrition. Considerable efforts should be focused on the treatment of RLS, since it significantly and persistently impacts the quality of life of HD patients. Kidney transplantation could represent an effective treatment option for that RLS impacts on dialysis patients' quality of life, thus confirming the secondary nature of RLS in most HD patients

White organic light-emitting devices with CdSe/ZnS quantum dots as a red emitter

White hybrid organic/inorganic light-emitting devices (LEDs) have been fabricated by using stable red-emitting CdSe/ZnS core-shell quantum dots (QDs) covered with a trioctylphosphine oxide organic ligand. The device-active structure consists in a host/guest system with a blue-emitting poly[(9,9-dihexyloxyfluoren-2,7-diyl)-alt-co-(2-methoxy-5-{2-ethylhexyloxy} phenylen-1,4-diyl)] (PFH-MEH) polymer doped with red-emitting QDs and a green emitting metal chelate complex Alq3, with improved electron injection and transfer properties. A fairly pure white OLED with Commission Internationale de lEclairage coordinates of (0.30,0.33) is fabricated by accurate control of the Förster energy and charge-transfer mechanisms between the different device constituents obtained by tuning the concentration ratio of the QDs/PFH-MEH blend. In particular, charge-transfer processes to CdSe/ZnS core-shell quantum dots are found to be the key element for well-balanced white emission. Maximum external quantum efficiency up to 0.24% at 1 mA cm-2 and 11 V in air atmosphere are reported, showing that hybrid LEDs can be a promising route towards more stable and efficient light-emitting devices for lighting applications. © 2005 American Institute of Physics

Selective reactions on the tips of colloidal semiconductor nanorods

A strategy to access several types of Au-tipped dumbbell-like nanocrystal heterostructures is presented, which involves the selective oxidation of either PbSe or CdTe sacrificial domains, initially grown on CdSe and CdS nanorods, with a Au(III) : surfactant complex. The formation of gold patches is supported by TEM, XRD and elemental analysis. This approach has allowed us to grow Au domains onto specific locations of anisotropically shaped nanocrystals for which direct metal deposition is unfeasible, as for the case of CdS nanorods. We believe that this strategy may be of general utility to create other types of complex colloidal nanoheterostructures, provided that a suitable sacrificial material can be grown on top of the starting nanocrystal seeds

High Q-factor colloidal nanocrystal-based vertical microcavity by hot embossing technology

We report on the fabrication and optical characterization of vertical hybrid microcavities in which a layer of colloidal nanocrystals dispersed in an organic matrix is embedded between two inorganic mirrors. The devices are fabricated by a technique based on the unconventional use of the hot embossing technology, which allows a very fine control of the cavity length. The technique exploits a λ -thick microstructured dielectric top mirror pressed onto the bottom one, previously coated with the active layer, to sandwich the cavity and precisely control its thickness. Room-temperature photoluminescence measurements show a Q factor as high as 146 for our devices