653 research outputs found

    Antisense reduction of thylakoidal ascorbate peroxidase in Arabidopsis enhances Paraquat-induced photooxidative stress and Nitric Oxide-induced cell death

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    The production and characterization of Arabidopsis plants containing a transgene in which the Arabidopsis tAPX is inserted in antisense orientation, is described. tAPX activity in these transgenic tAPX plants is around 50% of control level. The tAPX antisense plants are phenotypically indistinguishable from control plants under normal growth conditions; they show, however, enhanced sensitivity to the O 2- -generating herbicide, Paraquat. Interestingly, the tAPX antisense plants show enhanced symptoms of damage when cell death is triggered through treatment with the nitric oxide-donor, SNP. These results are in accordance with the ones recently obtained with transgenic plants overexpressing tAPX; altogether, they suggest that tAPX, besides the known ROS scavenging role, is also involved in the fine changes of H 2O2 concentration during signaling events

    How to better exploit the use of LCA analysis for Ultra High Performance Concrete (UHPC) through a constitutive law which integrates chloride and sulfate attack

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    Structural applications of advanced cementitious materials such as Ultra High Performance Concrete (UHPC) have been already assessed in harsh exposure conditions with presence of chlorides or sulfates. Nevertheless, the limited availability of design standards has not favoured so far a widespread use of these materials. Moreover, previous studies employed a constitutive model only partially representative of the real behavior of such materials when exposed to aggressive conditions. Therefore, this work, employing a “scenario dependent” constitutive law, estimates the serviceability limit state in correspondence of which it is needed to carry out the maintenance activities and investigates, through the Life Cycle Assessment (LCA) methodology, the ecological and economic profile of a UHPC water basin structure subjected to chloride and sulfate attack. The CML impact assessment method has been employed for the specific purpose to compare such structure to one made with ordinary reinforced concrete (ORC) using as system boundary the A1-B7 stages indicated in EN 15804

    Radiations and female fertility

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    Hundreds of thousands of young women are diagnosed with cancer each year, and due to recent advances in screening programs, diagnostic methods and treatment options, survival rates have significantly improved. Radiation therapy plays an important role in cancer treatment and in some cases it constitutes the first therapy proposed to the patient. However, ionizing radiations have a gonadotoxic action with long-term effects that include ovarian insufficiency, pubertal arrest and subsequent infertility. Cranial irradiation may lead to disruption of the hypothalamic-pituitary-gonadal axis, with consequent dysregulation of the normal hormonal secretion. The uterus might be damaged by radiotherapy, as well. In fact, exposure to radiation during childhood leads to altered uterine vascularization, decreased uterine volume and elasticity, myometrial fibrosis and necrosis, endometrial atrophy and insufficiency. As radiations have a relevant impact on reproductive potential, fertility preservation procedures should be carried out before and/or during anticancer treatments. Fertility preservation strategies have been employed for some years now and have recently been diversified thanks to advances in reproductive biology. Aim of this paper is to give an overview of the various effects of radiotherapy on female reproductive function and to describe the current fertility preservation options

    Coding sequences of sarcoplasmic reticulum calcium ATPase regulatory peptides and expression of calcium regulatory genes in recurrent exertional rhabdomyolysis

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    Background: Sarcolipin (SLN), myoregulin (MRLN), and dwarf open reading frame (DWORF) are transmembrane regulators of the sarcoplasmic reticulum calcium transporting ATPase (SERCA) that we hypothesized played a role in recurrent exertional rhabdomyolysis (RER). Objectives: Compare coding sequences of SLN, MRLN, DWORF across species and between RER and control horses. Compare expression of muscle Ca2+ regulatory genes between RER and control horses. Animals: Twenty Thoroughbreds (TB), 5 Standardbreds (STD), 6 Quarter Horses (QH) with RER and 39 breed-matched controls. Methods: Sanger sequencing of SERCA regulatory genes with comparison of amino acid (AA) sequences among control, RER horses, human, mouse, and rabbit reference genomes. In RER and control gluteal muscle, quantitative real-time polymerase chain reaction of SERCA regulatory peptides, the calcium release channel (RYR1), and its accessory proteins calsequestrin (CASQ1), and calstabin (FKBP1A). Results: The SLN gene was the highest expressed horse SERCA regulatory gene with a uniquely truncated AA sequence (29 versus 31) versus other species. Coding sequences of SLN, MRLN, and DWORF were identical in RER and control horses. A sex-by-phenotype effect occurred with lower CASQ1 expression in RER males versus control males (P \u3c .001) and RER females (P = .05) and higher FKBP1A (P = .01) expression in RER males versus control males. Conclusions and Clinical Importance: The SLN gene encodes a uniquely truncated peptide in the horse versus other species. Variants in the coding sequence of SLN, MLRN, or DWORF were not associated with RER. Males with RER have differential gene expression that could reflect adaptations to stabilize RYR1

    Symbolic dynamics for the NN-centre problem at negative energies

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    We consider the planar NN-centre problem, with homogeneous potentials of degree -\a<0, \a \in [1,2). We prove the existence of infinitely many collisions-free periodic solutions with negative and small energy, for any distribution of the centres inside a compact set. The proof is based upon topological, variational and geometric arguments. The existence result allows to characterize the associated dynamical system with a symbolic dynamics, where the symbols are the partitions of the NN centres in two non-empty sets

    Magnetic Moments and Electron Transport through Chromium-Based Antiferromagnetic Nanojunctions

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    We report the electronic, magnetic and transport properties of a prototypical antiferromagnetic (AFM) spintronic device. We chose Cr as the active layer because it is the only room-temperature AFM elemental metal. We sandwiched Cr between two non-magnetic metals (Pt or Au) with large spin-orbit coupling. We also inserted a buffer layer of insulating MgO to mimic the structure and finite resistivity of a real device. We found that, while spin-orbit has a negligible effect on the current flowing through the device, the MgO layer plays a crucial role. Its effect is to decouple the Cr magnetic moment from Pt (or Au) and to develop an overall spin magnetization. We have also calculated the spin-polarized ballistic conductance of the device within the Buttiker-Landauer framework, and we have found that for small applied bias our Pt/Cr/MgO/Pt device presents a spin polarization of the current amounting to similar or equal to 25%

    Thirty Years with EoS/G<sup>E</sup> Models - What Have We Learned?

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