Relaxation processes and intermolecular interactions in PVME hydrogels in sub-zero temperatures: Glass transition and pre-melting of ice

The phase transition observed by various methods in poly(vinyl methyl ether)/water systems at around 18 °C has been assigned by some investigators to the pre-melting of water and by others to a glass transition of the polymer. In this study, broadband dielectric spectroscopy and temperature modulated differential scanning calorimetry were used to identify this transition in radiationally crosslinked poly(vinyl methyl ether) hydrogels, as well as to analyse sub-zero relaxation processes in such a three-phase (polymer/ice/liquid water) system. The process at 18 °C was related to the pre-melting of water induced by the segmental motions of the polymer; however, it was seen to be one transition due to the cooperative motions of both compounds. The atypical (two regimes) temperature dependence of the segmental motion process was observed and was related to confinement of the polymer chains between ice clusters below approximately ?24 °C; furthermore, the main dielectric process of hexagonal ice was identified and a Maxwell-Wagner effect was observed.     

Detection of clenbuterol in beef meat,liver and kidney by mid‐infrared spectroscopy (FT‐Mid IR) and multivariate analysis

Mid‐infrared spectroscopy (FT‐Mid IR) coupled with multivariate analysis was used to predict clenbuterol in beef meat, liver and kidney. A SIMCA model was also developed to discriminate between pure (beef meat, liver and kidney) and spiked with clenbuterol samples (beef meat‐clenbuterol, liver‐clenbuterol and kidney‐clenbuterol). The best models to predict clenbuterol concentrations were obtained using the partial least squares algorithm (PLS) with a R² > 0.9 and SEC and standard error of prediction <0.296 and 0.324, respectively. The SIMCA model used to discriminate pure and spiked with clenbuterol samples showed 100% correct classification rate. Methods detection limit was 2 μg kg^?1. FT‐Mid IR coupled with chemometrics could be a simple and rapid screening tool for monitoring clenbuterol in beef meat, liver and kidney implicated in food poisoning. This method could be use for screening purposes.     

An Empirical Approach to Spanish Anaphora Resolution

This paper documents the development of an empirically-basedsystem implemented in Prolog that automatically resolves severalkinds of anaphora in Spanish texts. These are pronominalreferences, surface-count anaphora, one-anaphora and ellipticalzero-subject constructions (i.e., sentences that omit theirpronominal subject). The resolution is based onrepresentations resulting from either partial or full parsing. Thesystem developed can also work on the output of a POStagger or with different dictionaries, without changing thegrammar. This grammar represents the syntactic information of eachlanguage by means of the Slot Unification Grammar formalism. The different kinds of information used for anaphora resolution in full and partial parsing are shown, as wellas evaluation results. The system has been adapted toEnglish texts, obtaining encouraging results that prove that itcan be applied with only a very few refinements to other languagesas well as Spanish and English. In addition, the differencesbetween English and Spanish anaphora are noted.     

Intentional and incidental memory: Order effects in clinical testing.

Clinicians sometimes worry that the administration of intentional memory tests early in a clinical battery might artificially enhance performance on subsequent incidental memory tests, with possible differential effects for younger vs. older adults. Eighty-one healthy adults (ages 30–80) were blindly assigned to 1 of 2 testing conditions (incidental followed by intentional and vice versa). Contrary to the concerns of some, administration of intentional tests prior to incidental tests did not affect performance on any measures, and there was no interaction with age. Order of administration did not affect performance in older or younger adults. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Greenhouse effect reduction and energy recovery from waste landfill

Waste management systems are a non-negligible source of greenhouse gases. In particular, methane and carbon dioxide emissions occur in landfills due to the breakdown of biodegradable carbon compounds operated on by anaerobic bacteria. The conventional possibilities of reducing the greenhouse effect (GHE) from waste landfilling consists in landfill gas (LFG) flaring or combustion with energy recovery in reciprocating engines. These conventional treatments are compared with three innovative possibilities: the direct LFG feeding to a fuel cell (FC); the production of a hydrogen-rich gas, by means of steam reforming and CO₂ capture, to feed a stationary FC; the production of a hydrogen-rich gas, by means of steam reforming and CO₂ capture, to feed a vehicle FC. The comparison is carried out from an environmental point of view, calculating the specific production of GHE per unit mass of waste disposed in landfill equipped with the different considered technologies.     

Quantification of carbon nanotube induced adhesion of osteoblast on hydroxyapatite using nano-scratch technique

This paper explores the nano-scratch technique for measuring the adhesion strength of a single osteoblast cell on a hydroxyapatite (HA) surface reinforced with carbon nanotubes (CNTs). This technique efficiently separates out the contribution of the environment (culture medium and substrate) from the measured adhesion force of the cell, which is a major limitation of the existing techniques. Nano-scratches were performed on plasma sprayed hydroxyapatite (HA) and HA-CNT coatings to quantify the adhesion of the osteoblast. The presence of CNTs in HA coating promotes an increase in the adhesion of osteoblasts. The adhesion force and energy of an osteoblast on a HA-CNT surface are 17 ± 2 μN/cell and 78 ± 14 pJ/cell respectively, as compared to 11 ± 2 μN/cell and 45 ± 10 pJ/cell on a HA surface after 1 day of incubation. The adhesion force and energy of the osteoblasts increase on both the surfaces with culture periods of up to 5 days. This increase is more pronounced for osteoblasts cultured on HA-CNT. Staining of actin filaments revealed a higher spreading and attachment of osteoblasts on a surface containing CNTs. The affinity of CNTs to conjugate with integrin and other proteins is responsible for the enhanced attachment of osteoblasts. Our results suggest that the addition of CNTs to surfaces used in medical applications may be beneficial when stronger adhesion of osteoblasts is desired.     

Biomass integrated gasification combined cycle with reduced CO2 emissions: Performance analysis and life cycle assessment (LCA)

Performance analysis and life cycle assessment (LCA) of an integrated gasification combined cycle (IGCC) fed with biomass with upstream CO₂ chemical absorption has been carried out. The main working conditions have been determined by mean of partial exergetic analysis. A sensitivity analysis with respect to the CO₂ absorbing solution composition has also been carried out. The reachable efficiency ranges between 35% and 36%, depending on gas turbine technology level. In comparison with efficiency values previously found for an IGCC fed with coal with upstream CO₂ chemical absorption (38–39%), the configuration studied seems to be attractive because of the possibility of operating with a simplified scheme (without H₂S removal process) and at atmospheric pressure and for the possibility of using biomass in a more efficient way with respect to conventional combustion systems. Due to the lower efficiency, the specific CO₂ emission results higher (170 kg/MW h) with respect to the cycle fed with coal and CO₂ removal (130 kg/MW h). Moreover, the CO₂ balance has been determined with respect to the entire life cycle of the plant, including the construction, operation, dismantling and the biomass growing phases.     

Carbon dioxide removal in power generation using membrane technology

Carbon dioxide separation by means of membranes from methane reformed synthesis gas and from semi-closed cycle flue gases has been studied. In the first case, removing carbon dioxide using membrane is more energy consuming than removing it, from the same synthesis gas, using chemical absorption, leading to overall energy conversion efficiency of about 39% for the recuperated-auto thermal reforming (R-ATR) cycle equipped with membrane vs. 45% for the same R-ATR equipped with chemical absorption. With reference to the semi-closed cycle, the net cycle efficiency in the case of membrane removal (42.7%) seems to be not very far from the chemical absorption case (46%). Finally, published data about CO₂ membrane separation specific cost have been analysed, showing that the membrane technology for flue gas application can be competitive with respect to chemical absorption if CO₂ flue gas concentration is higher than 10%.