362 research outputs found

    Plant adaptation to extreme environments: The example of Cistus salviifolius of an active geothermal alteration field

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    Cistus salviifolius is able to colonise one of the most extreme active geothermal alteration fields in terms of both soil acidity and hot temperatures. The analyses of morphofunctional and physiological characters, investigated in leaves of plants growing around fumaroles (G leaves) and in leaves developed by the same plants after transfer into growth chamber under controlled conditions (C leaves) evidenced the main adaptive traits developed by this pioneer plant in a stressful environment. These traits involved leaf shape and thickness, mesophyll compactness, stomatal and trichome densities, chloroplast size. Changes of functional and physiological traits concerned dry matter content, peroxide and lipid peroxidation, leaf area, relative water and pigment contents. A higher reducing power and antioxidant enzymatic activity were typical of G leaves. Though the high levels of stress parameters, G leaves showed stress-induced specific morphogenic and physiological responses putatively involved in their surviving in active geothermal habitats

    Morpho-physiological plasticity contributes to tolerance of Calluna vulgaris in an active geothermal field

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    Geothermal alteration fields are very prohibitive environments, limiting vegetation establishment and growth. In the present study, the ecological specialisation of the pioneer plant Calluna vulgaris (L.) Hull was investigated, assuming that its ability to survive in geothermal habitats derives from a fine regulation of morpho-physiological traits. Mature leaves of C. vulgaris were sampled from plants close to a fumarole (near), and from plants living at a distance of some metres (intermediate) or ~1 km (distant) from a fumarole. Along the sampling sites, a gradient of soil-pH and temperature values occurred, with near plants facing the highest soil temperature and the lowest soil pH. A regulation of constitutive morpho-anatomical and physiological traits in response to different stress levels occurred. A progressive reduction of leaf exposed surface and hair density and mucilages, combined with a gradual increase of oxidative stress levels, of phenols and ascorbate, was observed from distant to near plants. Near plants showed an increase in stomatal density and in lignin and cuticle thickness, and the highest activity of ascorbate peroxidase. Except for high glutathione concentrations, in distant plants antioxidant machinery was consistently less active. The apparent morphological and physiological plasticity demonstrated in the present research contributed to the capability of these plants to tolerate the prohibitive, highly changing environmental conditions of the geothermal field

    First Finding of Ostreopsis cf. ovata Toxins in Marine Aerosols

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    Since the late 1990s, a respiratory syndrome has been repetitively observed in humans concomitant with Ostreopsis spp. blooms (mainly O. cf. ovata) in the Mediterranean area. Previous studies have demonstrated that O. cf. ovata produces analogues of palytoxin (ovatoxins and a putative palytoxin), one of the most potent marine toxins. On the basis of the observed association between O. cf. ovata blooms, respiratory illness in people, and detection of palytoxin complex in algal samples, toxic aerosols, containing Ostreopsis cells and/or the toxins they produce, were postulated to be the cause of human illness. A small scale monitoring study of marine aerosol carried out along the Tuscan coasts (Italy) in 2009 and 2010 is reported. Aerosols were collected concomitantly with O. cf. ovata blooms, and they were analyzed by both PCR assays and LC-HRMS. The results, besides confirming the presence of O. cf. ovata cells, demonstrated for the first time the occurrence of ovatoxins in the aerosol at levels of 2.4 pg of ovatoxins per liter of air. Given the lack of toxicological data on palytoxins by inhalation exposure, our results are only a first step toward a more comprehensiveunderstanding of the Ostreopsis-related respiratory syndrome

    Effects of charge doping on Mott insulator with strong spin-orbit coupling, Ba2_2NaOsO6_6

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    The effects of doping on the electronic evolution of the Mott insulating state have been extensively studied in efforts to understand mechanisms of emergent quantum phases of materials. The study of these effects becomes ever more intriguing in the presence of entanglement between spin and orbital degrees of freedom. Here, we present a comprehensive investigation of charge doping in the double perovskite Ba2_2NaOsO6_6, a a complex Mott insulator where such entanglement plays an important role. We establish that the insulating magnetic ground state evolves from canted antiferromagnet (cAF)to N\'eel order for dopant levels exceeding ~ 10 %. Furthermore, we determine that a broken local point symmetry (BLPS) phase, precursor to the magnetically ordered state, occupies an extended portion of the (H-T) phase diagram with increased doping. This finding reveals that the breaking of the local cubic symmetry is driven by a multipolar order, most-likely of the antiferro-quadrupolar type

    Surgical site infection after caesarean section. Space for post-discharge surveillance improvements and reliable comparisons

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    Surgical site infections (SSI) after caesarean section (CS) represent a substantial health system concern. Surveying SSI has been associated with a reduction in SSI incidence. We report the findings of three (2008, 2011 and 2013) regional active SSI surveillances after CS in community hospital of the Latium region determining the incidence of SSI. Each CS was surveyed for SSI occurrence by trained staff up to 30 post-operative days, and association of SSI with relevant characteristics was assessed using binomial logistic regression. A total of 3,685 CS were included in the study. A complete 30 day post-operation follow-up was achieved in over 94% of procedures. Overall 145 SSI were observed (3.9% cumulative incidence) of which 131 (90.3%) were superficial and 14 (9.7%) complex (deep or organ/space) SSI; overall 129 SSI (of which 89.9% superficial) were diagnosed post-discharge. Only higher NNIS score was significantly associated with SSI occurrence in the regression analysis. Our work provides the first regional data on CS-associated SSI incidence, highlighting the need for a post-discharge surveillance which should assure 30 days post-operation to not miss data on complex SSI, as well as being less labour intensive

    Spin-orbital Jahn-Teller bipolarons

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    Polarons and spin-orbit (SO) coupling are distinct quantum effects that play a critical role in charge transport and spin-orbitronics. Polarons originate from strong electron-phonon interaction and are ubiquitous in polarizable materials featuring electron localization, in particular 3d transition metal oxides (TMOs). On the other hand, the relativistic coupling between the spin and orbital angular momentum is notable in lattices with heavy atoms and develops in 5d TMOs, where electrons are spatially delocalized. Here we combine ab initio calculations and magnetic measurements to show that these two seemingly mutually exclusive interactions are entangled in the electron-doped SO-coupled Mott insulator Ba2Na1−xCaxOsO6 (0 < x < 1), unveiling the formation of spin-orbital bipolarons. Polaron charge trapping, favoured by the Jahn-Teller lattice activity, converts the Os 5d1 spin-orbital Jeff = 3/2 levels, characteristic of the parent compound Ba2NaOsO6 (BNOO), into a bipolaron 5d2 Jeff = 2 manifold, leading to the coexistence of different J-effective states in a single-phase material. The gradual increase of bipolarons with increasing doping creates robust in-gap states that prevents the transition to a metal phase even at ultrahigh doping, thus preserving the Mott gap across the entire doping range from d1 BNOO to d2 Ba2CaOsO6 (BCOO)

    A bio-guided assessment of the anti-inflammatory activity of hop extracts (Humulus lupulus L. cv. Cascade) in human gastric epithelial cells

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    The present work aims to characterize and investigate the anti-inflammatory activity of hop extracts (cv. Cascade) in an in vitro model of gastric inflammation. The biological activities of hydroalcoholic and aqueous extracts from cones were evaluated by comparing IL-8 inhibition induced by TNF\u3b1. The hydroalcoholic extract demonstrated a higher inhibitory effect, which was just slightly affected by an in vitro simulated gastric digestion. The identification of active compounds was performed by a bio-guided fractionation which afforded 11 fractions, one of which inhibited IL-8 release in a concentration-dependent fashion in human gastric epithelial AGS cells. Phytochemical analysis revealed xanthohumol A and xanthohumol D as the main active components. The present study provides some experimental evidences that Humulus lupulus L. may exert an anti-inflammatory activity on the gastric district by the inhibition of the IL-8 secretion, partially due to its prenylated chalcones content

    Azimuthal correlation between beauty particles produced in 350 GeV/c π−\pi^{-}-Cu interactions

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    Using a sample of 10810^8 triggered events, produced in 350 GeV/c350\, \hbox{GeV}/c π−\pi^- interactions in a copper target, we have identified 2626 b\=b events. These include 1313 events where the decays of both BB and B‾\overline{B} are well reconstructed. We measure the azimuthal \hbox{correlation} between beauty particles, and compare our result with predictions based on perturbative QCD

    Measurements of charmed-meson production in interactions between 350 GeV/c π−\pi^- particles and nuclei

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    Charmed-meson production by 350350~GeV/cc {π−\pi^-} particles incident on copper and tungsten targets has been studied in the WA9292 experiment, performed at the CERN Ω′\Omega^\prime spectrometer. Results obtained are reported and discussed. Reconstruction of decays from the set D0→K−π+{\rm D}^0 \rightarrow {\rm K}^- \pi^+, D0→K−π−π+π+{\rm D}^0 \rightarrow {\rm K}^- \pi^- \pi^+ \pi^+, D+→K−π+π+{\rm D}^+ \rightarrow {\rm K}^- \pi^+ \pi^+, Ds+→ϕπ+{{\rm D}_{\rm s}}^+ \rightarrow \phi \pi^+ and charge conjugates has yielded a sample of 7280±1087280 \pm 108 charmed mesons, produced with \xf > 0, \langle \xf \rangle = 0.18 and \langle {\pt}^2 \rangle = 1.86~{\rm (GeV/}c{\rm )}^2. Assuming a relationship σ=σ0Aα\sigma = \sigma_0 A^\alpha between the cross-section, σ\sigma, per nucleus of mass AA and the nucleonic cross-section, σ0\sigma_0, the α\alpha value found for the detected charmed particles is 0.95±0.06±0.030.95 \pm 0.06 \pm 0.03. Taking α=1\alpha = 1, the measured cross-sections per nucleon for \xf > 0 production are 7.78±0.14±0.527.78 \pm 0.14 \pm 0.52~μ\mubarn for D0{\rm D}^0/Dˉ0\bar{\rm D}^0, 3.28±0.08±0.293.28 \pm 0.08 \pm 0.29~μ\mubarn for D+{\rm D}^+/D−{\rm D}^- and 1.29±0.16±0.331.29 \pm 0.16 \pm 0.33~μ\mubarn for Ds+{{\rm D}_{\rm s}}^+/Ds−{{\rm D}_{\rm s}}^-. Differential cross-sections with respect to \xf and {\pt}^2 have been determined for the various types of charmed meson, and particle-antiparticle asymmetries have been analysed
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