Phenol content related to antioxidant and antimicrobial activities of Passiflora spp. extracts

Methanolic extracts were prepared from different organs of plants from five Passiflora species obtained by zygotic embryo culture and evaluated for their capacity to quench DPPH and ABTS^•+ radicals in comparison to that of Trolox, a water soluble vitamin-E analogue. Moreover their antimicrobial activity against E. coli was tested by agar diffusion and turbidity assays. P. nitida, P. foetida, and P. palmeri showed antimicrobial activity. P. nitida and P. palmeri also showed high antioxidant activity. P. tenuifila and P. coriacea demonstrated antioxidant power but not antimicrobial activity. The phenolic content of the different extracts was studied and quantified by spectrophotometric methods, HPLC, and mass spectrometry. High antioxidant activity correlated with high amounts of o-diphenol and catechin. An unknown component, tentatively identified as structural isomer of isoschaftoside, appeared to correlate with antimicrobial activity.     

Cerium(IV)oxide modification by inclusion of a hetero-atom: A strategy for producing efficient and robust nano-catalysts for methanol carboxylation

Cerium(IV) oxide has been reported to catalyse the direct carboxylation of methanol to dimethylcarbonate, DMC. Nevertheless, the life of commercially available catalysts is quite short as after the first cycle the activity decreases and after a few cycles goes to zero. Noteworthy, no reports are in the literature about the stability of catalysts and their life. We have investigated the behaviour of catalysts and their de-activation using either surface techniques, such as XPS, or structural techniques, such as XRD. The reduction of Ce(IV) to Ce(III) and surface modification seem to be responsible for de-activation of the oxide. The results of a detailed study correlating the size and structure of particles to the activity of the catalysts are reported in this paper. In particular, pure commercial CeO₂ is compared, using High Throughput Experiments (HTE), with CeO₂ synthesised in our laboratory and with the latter loaded with Al or Fe at various concentrations. The hetero-metals have a different effect on the stabilization of the Ce-catalyst and on its activity. Al-loaded CeO₂ affords the most interesting results in terms of lifetime and activity. Therefore, the correlation of the structural properties of CeO₂ loaded with Al at a concentration variable between 3 and 40% to the activity in catalysis is discussed in detail. XPS and XRD data have been used for the characterization of the catalyst before and after a catalytic run. Pure synthesised CeO₂ and CeO₂ loaded with Al are able to maintain their activity for several cycles (apparent TON of several tens) or three days of operation without any treatment after recovery, with a much better performance than the commercial catalysts that, conversely, loose their activity after a few cycles. The size of the particles determines the activity of the catalyst and we show that particles having a size 15–60 nm are the most active, while particles sized micrometers are much less active.     

A CBR-BASED, CLOSED-LOOP ARCHITECTURE FOR TEMPORAL ABSTRACTIONS CONFIGURATION

In the hemodialysis domain, we are implementing a case-based, closed-loop architecture aimed at configuring temporal abstractions (TA), which will be applied to time series data. The advantage of a case-based approach is the one of "quickly" obtaining a suitable TA parameter configuration, simply by looking at the most similar already configured case, where configured cases are indexed by means of contextual information. The retrieved configuration, together with the time series data, is then used as an input to a TA processing module, able to provide a set of qualitative states, trends, and significant combinations of both as an output. TA processing results can finally be evaluated, possibly leading to a (human-supervized) reorganization/revision of the case base content, to ameliorate future TA configuration sessions—thus closing the loop. The work is being integrated with RHENE, a system for case-based retrieval in hemodialysis, able to work both on raw time series data and on preprocessed (by means of TA) ones.     

Thermodynamics of Surfactants, Block Copolymers and Their Mixtures in Water: The Role of the Isothermal Calorimetry

The thermodynamics of conventional surfactants, block copolymers and their mixtures in water was described to the light of the enthalpy function. The two methodologies, i.e. the van’t Hoff approach and the isothermal calorimetry, used to determine the enthalpy of micellization of pure surfactants and block copolymers were described. The van’t Hoff method was critically discussed. The aqueous copolymer+surfactant mixtures were analyzed by means of the isothermal titration calorimetry and the enthalpy of transfer of the copolymer from the water to the aqueous surfactant solutions. Thermodynamic models were presented to show the procedure to extract straightforward molecular insights from the bulk properties.     

Novel Lithium Ion Batteries Based on a Tin Anode and on Manganese Oxide Cathodes

In this paper we report two innovative lithium ion batteries formed by the combination of a nanosized tin anode and a LiNi_0.5Mn_1.5O₄ or a LiNi_0.33Co_0.33Mn_1.33O₂ cathode. The batteries have a very stable cycling response at a high rate of 1C with an excellent capacity delivery, i.e., 140 mAhg⁻¹ and 175 mAhg⁻¹, respectively. Estimated energy density values are of the order of 150 Whkg⁻¹ for both batteries.     

Cationic cyclometallated iridium(III) complexes with substituted 1,10-phenanthrolines: the role of the cyclometallated moiety on this new class of complexes with interesting luminescent and second order non linear optical properties

The luminescence and second order non linear optical (NLO) response of [Ir(ttpy)₂(5-R-1,10-phen)][PF₆] (ttpy = cyclometallated 3′-(2-pyridil)-2,2′:5′,2″-terthiophene, phen = phenanthroline; R = Me, NO₂) and [Ir(pq)₂(5-R-1,10-phen)][PF₆] (pq = cyclometallated 2-phenylquinoline) have been investigated experimentally in CH₂Cl₂ solution and compared with that of [Ir(ppy)₂(5-R-1,10-phen)][PF₆] (ppy = cyclometallated 2-phenylpyridine), characterized by one of the highest second order NLO response ever reported for a metal complex. Substitution of ppy with the more π-delocalized pq does not affect significantly the luminescence and NLO properties. A slightly lower NLO response and a much poorer luminescence is observed for the related complexes with ttpy. In these complexes, DFT/TDDFT calculations show that the presence of ttpy induces a significant downshift of the HOMO energy, compared to ppy and pq. The NLO response is dominated by intense MLCT excited states, which are also assigned as originating the emission.     

Relationships between microstructure and transport properties of proton-conducting porous PVDF membranes

Fluorinated polymers are today investigated as possible alternatives to Nafion™ in PEM Fuel Cells. In this paper, we study the relationships between the microstructure and the proton transport of porous PVDF homopolymer membranes swollen by 11 M aqueous solution of H₃PO₄. The analysis is performed on membranes with different nominal pores size values, d_p. The membranes are thermally stable at least up to 250 °C. A dependence of the proton transport on the pores size has been found, that is particularly evident for low d_p values and at low relative humidity (R.H.). Conductivity values exceeding 0.1 S cm⁻¹ are obtained at 80 °C even at 10% R.H. for d_p ≥ 0.22 μm. We show that the behaviour of the transport properties cannot be simply rationalized in terms of d_p, but it requires an accurate knowledge of the membrane microstructure (tortuosity, pores interconnections and size distributions). ³¹P NMR spectroscopy also shows that anisotropic interactions take place between the components of the solution and at a lower extent, between the solution and the pores walls, also for d_p values in the micrometer range. In order to make a preliminary check of the suitability of these membranes for applications in Direct Methanol Fuel Cells (DMFCs), studies of methanol crossover and diffusion through the membrane have been carried out and compared with those of Nafion™.     

Exploiting decision theory concepts within clinical guideline systems: Toward a general approach

Supporting therapy selection is a fundamental task for a system for computerized management of clinical guidelines (GL). To this end, decision theory concepts could provide significant advances. In this article, we propose a systematic analysis of the main GL representation primitives and of how they could be related to decision theory concepts. The knowledge representation contribution we provide can be seen as a basis for implementing a decision support tool within any of the systems described in the literature: As a matter of fact, at a sufficiently abstract level, the GL primitives we treat are shared by all of the systems. Such a tool could be adopted when executing a GL on a single patient (in clinical practice) and for simulation purposes. In particular, a decision theory tool based on this analysis is being implemented in the GLARE system. © 2006 Wiley Periodicals, Inc. Int J Int Syst 21: 585–599, 2006.     

Properties Enhancement of an Eco-Friendly Electrical Contact Material by Silver Nanoparticles Addition

Silver-tin oxide electrical contact material with 10?wt pct stannic oxide and balance nanosized and micronsized silver was developed successfully. Stannic oxide particles chemically coated by a layer of silver nanospheres are homogeneously dispersed in a silver microcrystalline matrix made by chemical synthesis. The material processed by pressing-sintering-repressing exhibited enhanced properties: density: 97.1 to 97.9?pct relative density, Vickers hardness: 103 to 115, electrical conductivity: 65 to 69?pct IACS, volumetric shrinkage: 28.9 to 30.9?pct, and a very fine and uniform microstructure.