421 research outputs found

    Polymorphism, phonon dynamics and carrier-phonon coupling in pentacene

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    The crystal structure and phonon dynamics of pentacene is computed with the Quasi Harmonic Lattice Dynamics (QHLD) method, based on atom-atom potential. We show that two crystalline phases of pentacene exist, rather similar in thermodynamic stability and in molecular density. The two phases can be easily distinguished by Raman spectroscopy in the 10-100 cm-1 spectral region. We have not found any temperature induced phase transition, whereas a sluggish phase change to the denser phase is induced by pressure. The bandwidths of the two phases are slightly different. The charge carrier coupling to low-frequency phonons is calculated.Comment: 6 pages, 3 figures. Presented at ICFPAM-

    Effect of Kaolin/Defoliation Combined with Dry Ice on Lambrusco Red Wine Production to Constrain the Effects of Climate Change

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    Since viticulture is affected considerably by climate change, it is imperative to encourage research on newstrategies in order to constrain these critical effects on the composition of berries and the quality of wines.A multi-strategy approach composed of (i) kaolin application on foliage, (ii) late tree defoliation and (iii)cryomaceration of grapes with dry ice was evaluated in the production of Lambrusco Salamino wines.Physical, chemical and sensory analyses were carried out on the sample set, including the control wines.In general, cryomaceration with dry ice proved to be a winning choice to lower alcoholic strength (roughly5%). In addition, the wines showed an increase in anthocyanin content by approximately 17%, while thecontent of catechins, flavanols and hydroxycinnamic acids decreased. Consistent with the increase in theanthocyanin content, an increase in colour indices and sensory colour intensity scores was observed. As forthe aromatic profile, 2-phenylethanol showed an increase of approximately 18% in the treated wines while,in parallel, a lower content of C6 alcohols and volatile fatty acids was observed. The multiple adaptationstrategies put in place in the present study show an alternative way to mitigate the severe effects of climatechange on wine production, and to face changing consumer demands

    Profile of red wine partially dealcoholized with a membrane-based technique and strategies to mitigate the loss of volatile compounds

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    : In recent years, climate change has led to higher grape must sugar content and, consequently, increased alcohol by volume. Evaporative or pertraction is a common method for post-fermentation ethanol removal from wines, but it selectively removes some less polar volatile compounds along with ethanol. To mitigate volatile substance loss, this study investigates blending of the red wine (Marzemino-Cabernet blend) with obtained dealcoholized samples from it by industrial evaporative pertraction system, while maintaining the final product within a two-percentage-point reduction in ethanol. Thus MIX 1 and MIX 2 blends were prepared, reducing the ABV of the initial wine (12.5% alcohol by volume) to 10.5% and 9.5%. Chemical analyses highlighted that most alcohols, acetates, and ethyl esters of fatty acids decreased with alcohol by volume reduction. However, compounds with polar groups (acetoin and acetovanillone), C13-norisoprenoids, and certain lactones showed increasing trends. Sensory analysis indicated high scores for sweetness and smoothness in the blended wines, with a decrease in acidic taste. Floral scents notably increased, particularly in MIX 2, closely resembling the initial wine's sensory profile. The blending of initial wine with appropriately dealcoholized wine samples has proven to be an effective strategy for preserving bouquet and color of dealcoholized wines. This approach broadens the consumer base by catering to people who prefer low-alcohol options, have dietary restrictions, or are health-conscious, but who still wish to savor wines with aromatic quality rather than a flat taste. This strategy is crucial in the wine industry as it successfully addresses technical challenges and ensures economic viability

    Role of Multiparametric-MRI in Bladder Cancer

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    Purpose of ReviewThis narrative review article aims to show the actual role of imaging, in particular MRI, and the role of VI-RADS Score, in recognition and follow-up of the tumor.Recent FindingsA team of professionals created VI-RADS with the goal of standardizing the acquisition and interpretation of multiparametric-MRI in bladder cancer.Bladder cancer is the most common cancer involving the urinary system. It is the fourth most common urological cancer in men and the second most frequent cancer affecting the urinary tract. Main risks factors are advanced age, male sex, and cigarette smoking. Bladder cancer ranges from unaggressive and usually non-invasive tumors that recur and commit patients to long-term invasive surveillance, to aggressive and invasive tumors with high disease-specific mortality. At the time of diagnosis, 70% of patients are experiencing non-muscle-invasive bladder cancer. Vesical imaging-reporting and data system score (VI-RADS) is a scoring system useful to standardize the approach to multiparametric-MRI interpretation, and reporting for bladder cancer

    Seasonal variability of the HO.RE.CA. food leftovers employed as a feeding substrate for black soldier fly (Hermetia illucens L.) larvae and effects on the rearing performance

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    The SCALIBUR project (Horizon, 2020) aimed to explore innovative solutions, including the use of black soldier fly larvae, for the bio-urban waste management. This research work describes the evaluation of the variability in water, proteins, fat, ashes, and carbohydrates present in the HO.RE.CA. food leftovers which were withdrawn from a local canteen over a 12-month period and the relationship with (i) the growth parameters of the larvae, (ii) the percentage of substrate reduction and the percentage of frass separated through the mechanical sieve at the end of the rearing process. HO.RE.CA. food leftovers are overall a suitable feeding substrate for larval rearing. Water contained in the HO.RE.CA. food leftovers was sufficient for larval rearing without resorting to further addition. As for water content, a seasonal trend was not observed, on the contrary, it was proved to be totally random. However, high amount of water (>80%) was correlated with higher larval mortality rate. The larval weight was significantly correlated to the amount of protein (r = 0.80; p ≤ 0.001) present in the substrate, and to a lesser extent to the amount of fat (r = 0.43; p ≤ 0.05). The feed conversion rate and bioconversion rate were both in agreement with literature data. The statistical test did not show any significant correlation between the amount of water contained in the initial fresh HO.RE.CA. food leftovers and the percentage of substrate reduction and the percentage of frass separated through the mechanical sieve at the end of the rearing process

    Direct evidence of overdamped Peierls-coupled modes in TTF-CA temperature-induced phase transition

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    In this paper we elucidate the optical response resulting from the interplay of charge distribution (ionicity) and Peierls instability (dimerization) in the neutral-ionic, ferroelectric phase transition of tetrathiafulvalene-chloranil (TTF-CA), a mixed-stack quasi-one-dimensional charge-transfer crystal. We present far-infrared reflectivity measurements down to 5 cm-1 as a function of temperature above the phase transition (300 - 82 K). The coupling between electrons and lattice phonons in the pre-transitional regime is analyzed on the basis of phonon eigenvectors and polarizability calculations of the one-dimensional Peierls-Hubbard model. We find a multi-phonon Peierls coupling, but on approaching the transition the spectral weight and the coupling shift progressively towards the phonons at lower frequencies, resulting in a soft-mode behavior only for the lowest frequency phonon near the transition temperature. Moreover, in the proximity of the phase transition, the lowest-frequency phonon becomes overdamped, due to anharmonicity induced by its coupling to electrons. The implications of these findings for the neutral-ionic transition mechanism is shortly discussed.Comment: 11 pages, 13 figure

    (Perylene)3-(TCNQF1)2: Yet Another Member in the Series of Perylene–TCNQFx Polymorphic Charge Transfer Crystals

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    The 3:2 Charge Transfer (CT) co-crystal (Perylene)3(TCNQF1)2 is grown by the Physical Vapor Transport (PVT) method, and characterized structurally and spectroscopically. Infrared analysis of the charge sensitive modes reveals a low degree of charge transfer (less than 0.1) between donor and acceptor molecules. The crystal is isostructural to the other 3:2 CT crystals formed by Perylene with TCNQF2 and TCNQF4, whereas such stoichiometry and packing is not known for the CT crystals with non-fluorinated TCNQ. The analysis of the isostructural family of 3:2 Perylene–TCNQFx (x = 1,2,4) co-crystal put in evidence the role of weak F…HC bonding in stabilizing this type of structure</jats:p
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