385 research outputs found

    Ozone damage and tolerance in leaves of two poplar genotypes.

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    The effects induced by an acute ozone exposure were investigated in two poplar hybrids differen- tially O3 susceptible in terms of leaf injuries: Populus deltoides x maximowiczii, Eridano clone and..

    Cadmium uptake, localization and stress-induced morphogenic response in the fern Pteris vittata.

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    Cadmium uptake, tissue localization and structural changes induced at cellular level are essential to understand Cd tolerance in plants. In this study we have exposed plants of Pteris vittata to different concentrations of CdCl2 (0, 30, 60, 100 μM) to evaluate the tolerance of the fern to cadmium. Cadmium content determination and its histochemical localization showed that P. vittata not only takes up, but also transports and accumulates cadmium in the aboveground tissues, delocalizing it mainly in the less bioactive tissues of the frond, the trichomes and the scales. Cadmium tolerance in P. vittata was strictly related to morphogenic response induced by the metal itself in the root system. Adaptive response regarded changes of the root apex size, the developmental pattern of root hairs, the differentiation of xylem elements and endodermal suberin lamellae. All the considered parameters suggest that, in our experimental conditions, 60 μM of Cd may represent the highest concentration that P. vittata can tolerate; indeed this Cd level even improves the absorbance features of the root and allows good transport and accumulation of the metal in the fronds. The results of this study can provide useful information for phytoremediation strategies of soils contaminated by Cd, exploiting the established ability of P. vittata to transport, delocalize in the aboveground biomass and accumulate polluting metals

    Ovatoxin-a, a palytoxin analogue isolated from Ostreopsis cf. ovata Fukuyo: cytotoxic activity and ELISA detection

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    This study provides the first evaluation of the cytotoxic effects of the recently identified palytoxin (PLTX) analog, ovatoxin-a (OVTX-a), the major toxin produced by Ostreopsis cf. ovata in the Mediterranean Sea. Its increasing detection during Ostreopsis blooms and in seafood highlights the need to characterize its toxic effects and to set up appropriate detection methods. OVTX-a is about 100 fold less potent than PLTX in reducing HaCaT cells viability (EC50 = 1.1 7 10 129 M vs 1.8 7 10 1211 M, MTT test) in agreement with a reduced binding affinity (Kd = 1.2 7 10 129 vs 2.7 7 10 1211 M, saturation experiments on intact cells). Similarly, OVTX-a hemolytic effect is lower than that of the reference PLTX compound. Ost-D shows the lowest cytotoxicity toward HaCaT keratinocytes, suggesting the lack of a hydroxyl group at C44 as a critical feature for PLTXs cytotoxic effects. A sandwich ELISA developed for PLTX detects also OVTX-a in a sensitive (LOD = 4.2 and LOQ = 5.6 ng/mL) and accurate manner (Bias = 0.3%), also in O. cf. ovata extracts and contaminated mussels. Although in vitro OVTXa appears less toxic than PLTX, its cytotoxicity at nanomolar concentrations after short exposure time rises some concern for human health. The sandwich ELISA can be a viable screening method for OVTXs detection in monitoring program

    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)

    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
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