545 research outputs found

    LEMONGRASS PLANT LEAF AND CULM AS POTENTIAL SOURCES OF REINFORCEMENT FOR BIO-COMPOSITES

    Get PDF
    A possible source of natural reinforcement for bio-composites can be represented by lemongrass plant (Cymbopogon flexuosus), a clumped and perennial grass which belongs to the Poaceae family. This plant is extensively used for several applications such as pharmacology, food preservation and cosmetics but, to the best of our knowledge, few papers were published on its use as source for reinforcement of composites and no one article was focused on the comparison between lemongrass leaves and culms as potential source of natural reinforcement. To this aim, a preliminary investigation on leaf and culm fibers was carried out to compare their physical and chemical features as well as their tensile properties. Furthermore, bio-composites based on a biodegradable starch-derived matrix (MaterBi®) and lemongrass leaf and culm particles were manufactured via extrusion and compression molding. For both fillers, two compositions (i.e., 10% and 20 wt.%) were investigated in terms of morphological and mechanical properties

    Application of technological protocols on an industrial scale to improve Seville-style table olive production in Italy and Spain

    Get PDF
    Improving the fermentation performance of starter strains used in the fermentation of table olives is a biotechnological solution of current interest to improve the quality characteristics of the final product. The aim of this study was to evaluate the use of Lactiplantibacillus pentosus OM13 as a starter culture for the fermentation of Seville-type table olives in two different production areas: Italy and Spain. The starter strain L. pentosus OM13 was inoculated into two different table olive varieties: Nocellara del Belice in Italy and Manzanilla in Spain. Lactiplantibacillus plantarum Vege-Start 60 was used as a commercial control, while an additional control pro- duction was carried out by spontaneous fermentation. The industrial productions consisted of three different protocols, differing in the type of nutrient and the presence/absence of acclimatisation of the starter strain. All trials were subjected to microbiological monitoring, evaluation of acidification dynamics and sensory analysis of the final product. After 90 days, the pH reached values below 5 in the different treatments. The LAB reached microbial loads varying between 6.5 and 8.7 log CFU/mL throughout the monitoring period. The microbial populations of spoilage and/or potential pathogenic microorganisms were variable depending on the microbial group monitored. However, after 12 days of fermentation, Enterobacteriaceae showed values below the detection limit. In contrast, a fluctuating trend was observed for yeasts, Pseudomonadaceae and Staphylococcaceae. Sensory analyses showed variable differences depending on the technological protocol used. Table olives ob- tained with L. pentosus OM13 in the presence of nutrient, activator and acclimatisation period achieved higher overall acceptability values compared to the other trials. The use of adjuvants (nutrients and activators) is a strategy used in the production of table olives fermented with L. pentosus OM13 to improve the sensory char- acteristics of table olives

    Beta, Dipole and Noncommutative Deformations of M-theory Backgrounds with One or More Parameters

    Full text link
    We construct new M-theory solutions starting from those that contain 5 U(1) isometries. We do this by reducing along one of the 5-torus directions, then T-dualizing via the action of an O(4,4) matrix and lifting back to 11-dimensions. The particular T-duality transformation is a sequence of O(2,2) transformations embedded in O(4,4), where the action of each O(2,2) gives a Lunin-Maldacena deformation in 10-dimensions. We find general formulas for the metric and 4-form field of single and multiparameter deformed solutions, when the 4-form of the initial 11-dimensional background has at most one leg along the 5-torus. All the deformation terms in the new solutions are given in terms of subdeterminants of a 5x5 matrix, which represents the metric on the 5-torus. We apply these results to several M-theory backgrounds of the type AdS_r x X^{11-r}. By appropriate choices of the T-duality and reduction directions we obtain analogues of beta, dipole and noncommutative deformations. We also provide formulas for backgrounds with only 3 or 4 U(1) isometries and study a case, for which our assumption for the 4-form field is violated.Comment: v2:minor corrections, v3:small improvements, v4:conclusions expanded, to appear in Class. Quant. Gra

    Mechanical ventilation and volutrauma: study in vivo of a healthy pig model

    Get PDF
    Mechanical ventilation is essential in intensive care units. However, it may itself induce lung injury. Current studies are based on rodents, using exceptionally large tidal volumes for very short periods, often after a "priming" pulmonary insult. Our study deepens a clinically relevant large animal model, closely resembling human physiology and the ventilator setting used in clinic settings. Our aim was to evaluate the pathophysiological mechanisms involved in alveolo/capillary barrier damage due to mechanical stress in healthy subjects. We randomly divided 18 pigs (sedated with medetomidine/tiletamine-zolazepam and anesthetised with thiopental sodium) into three groups (n=6): two were mechanically ventilated (tidal volume of 8 or 20 ml/kg), the third breathed spontaneously for 4 hours, then animals were sacrifi ced (thiopental overdose). We analyzed every 30' hemogasanalysis and the main circulatory and respiratory parameters. Matrix gelatinase expression was evaluated on bronchoalveolar lavage fl uid after surgery and before euthanasia. On autoptic samples we performed zymographic analysis of lung, kidney and liver tissues and histological examination of lung. Results evidenced that high V T evoked profound alterations of lung mechanics and structure, although low V T strategy was not devoid of side effects, too. Unexpectedly, also animals that were spontaneously breathing showed a worsening of the respiratory functions

    a smart nanofibrous material for adsorbing and detecting elemental mercury in air

    Get PDF
    Abstract. The combination of the affinity of gold for mercury and nanosized frameworks has allowed for the design and fabrication of novel kinds of sensors with promising sensing features for environmental applications. Specifically, conductive sensors based on composite nanofibrous electrospun layers of titania easily decorated with gold nanoparticles were developed to obtain nanostructured hybrid materials capable of entrapping and revealing gaseous elemental mercury (GEM) traces from the environment. The electrical properties of the resulting chemosensors were measured. A few minutes of air sampling were sufficient to detect the concentration of mercury in the air, ranging between 20 and 100 ppb, without using traps or gas carriers (LOD: 1.5 ppb). Longer measurements allowed the sensor to detect lower concentrations of GEM. The resulting chemosensors are expected to be low cost and very stable (due to the peculiar structure), requiring low power, low maintenance, and simple equipment

    High intensity X/ γ photon beams for nuclear physics and photonics

    Get PDF
    In this manuscript we review the challenges of Compton back-scattering sources in advancing photon beam performances in the1−20MeVenergy range, underlining the design criteria bringing tomaximum spectral luminosity and briefly describing the main achieve-ments in conceiving and developing new devices (multi-bunch RF cav-ities and Laser recirculators) for the case of ELI-NP Gamma BeamSystem (ELI-NP-GBS)

    Different dynamics of sensory-motor development and behavior during the transitional period in puppies : preliminary results

    Get PDF
    Many studies have analyzed the behavior of puppies during their socialization period, while little attention has been paid to the transitional period, when vision and hearing develop. Here, we compared the average age of sensory and motor development, and the behavior among a total of 25 puppies. Each litter was videotaped during 1-hour daily sessions on postnatal days 10-21 and coded for the following mutually exclusive behavioral categories: sleeping, suckling and moving. The moving category included side-to-side head swinging, exploring, rolling and allogrooming. The opening of the eyelids, appearance of the startle response and ability to stand up with either the front or hind legs were identified. The duration and frequency of puppy behaviors varied significantly with breed and season of birth. Breed and gender differences in gross motor and sensory development were also observed. These findings may turn out to be crucial to enhance the welfare, standards of rearing, and behavioral interventions aimed at improving adaptability to novel stimuli in pet dogs

    A KK-monopole giant graviton in AdS_5 x Y_5

    Full text link
    We construct a new giant graviton solution in AdS_5 x Y_5, with Y_5 a quasi-regular Sasaki-Einstein manifold, consisting on a Kaluza-Klein monopole wrapped around the Y_5 and with its Taub-NUT direction in AdS_5. We find that this configuration has minimal energy when put in the centre of AdS_5, where it behaves as a massless particle. When we take Y_5 to be S^5, we provide a microscopical description in terms of multiple gravitational waves expanding into the fuzzy S^5 defined as an S^1 bundle over the fuzzy CP^2. Finally we provide a possible field theory dual interpretation of the construction.Comment: 11 pages, published versio

    Three-dimensional geometrical models of the inguinal region. Towards a new stereology

    Get PDF
    In this work we studied the inguinal-abdominal region and the inguinal canal using three-dimensional geometrical models. We built the models through computer aided geometric modeling techniques on the basis of observations during real dissections, operations and diagnostic medical imaging. The obtained models show in a complete modular synthesis and with a schematic iconology the structural organization of the anatomical districts in a logic sequence of layers and topographic and spatial relationships among its components. The models represent an amazing support to anatomy and clinical anatomy for teaching and research purposes on organogenesis, surgery and diagnosis

    Sensitivity model study of regional mercury dispersion in the atmosphere

    Get PDF
    Atmospheric deposition is the most important pathway by which Hg reaches marine ecosystems, where it can be methylated and enter the base of food chain. The deposition, transport and chemical interactions of atmospheric Hg have been simulated over Europe for the year 2013 in the framework of the Global Mercury Observation System (GMOS) project, performing 14 different model sensitivity tests using two high-resolution three-dimensional chemical transport models (CTMs), varying the anthropogenic emission datasets, atmospheric Br input fields, Hg oxidation schemes and modelling domain boundary condition input. Sensitivity simulation results were compared with observations from 28 monitoring sites in Europe to assess model performance and particularly to analyse the influence of anthropogenic emission speciation and the Hg0(g) atmospheric oxidation mechanism. The contribution of anthropogenic Hg emissions, their speciation and vertical distribution are crucial to the simulated concentration and deposition fields, as is also the choice of Hg0(g) oxidation pathway. The areas most sensitive to changes in Hg emission speciation and the emission vertical distribution are those near major sources, but also the Aegean and the Black seas, the English Channel, the Skagerrak Strait and the northern German coast. Considerable influence was found also evident over the Mediterranean, the North Sea and Baltic Sea and some influence is seen over continental Europe, while this difference is least over the north-western part of the modelling domain, which includes the Norwegian Sea and Iceland. The Br oxidation pathway produces more HgII(g) in the lower model levels, but overall wet deposition is lower in comparison to the simulations which employ an O3 ∕ OH oxidation mechanism. The necessity to perform continuous measurements of speciated Hg and to investigate the local impacts of Hg emissions and deposition, as well as interactions dependent on land use and vegetation, forests, peat bogs, etc., is highlighted in this study
    • …
    corecore