Simulating radiation damage in a bcc Fe system with embedded yttria nanoparticles

This paper was accepted for publication in the journal Journal of Nuclear Materials and the definitive published version is available at http://dx.doi.org/10.1016/j.jnucmat.2013.02.016We present a molecular dynamics study of radiation damage arising from nuclear collisions close to embedded yttria nanoparticles in a bcc Fe matrix. The model assumes a perfect body-centred cubic (bcc) iron matrix in which yttria nano-particles are embedded as a simplified model of an Oxide Dispersion Strengthened steel. It is shown how the nano-particles interact with nearby initiated collision cascades, through cascade blocking and absorbing energy. Fe defects accumulate at the interface both directly from the ballistic collisions and also by attraction of defects generated close by. The nano-particles generally remain intact during a radiation event and release absorbed energy over times longer than the ballistic phase of the collision cascade

Effect of parenteral infusion of fish oil-based lipid emulsion on systemic inflammatory cytokines and lung eicosanoid levels in experimental acute pancreatitis

Aim: we evaluated the effect of short-term FOLE infusion before experimental induction of AP on systemic cytokine and lung eicosanoid profiles.Methods: Lewis rats (n = 72) received parenteral infusion of FOLE (FO group) or saline (SS group), or remained without parenteral infusion (CG group) for 48 h. Thereafter, AP was induced by retrograde injection of sodium taurocholate into the pancreatic duct. Animals were sacrificed after 2, 12 and 24 h. Blood and lung samples were collected to assess serum inflammatory cytokines (Luminex) and tissue eicosanoids (ELISA), respectively.Results: serum TNF-α increased over time and serum IL-10 decreased from 12 to 24 h in CG group. In SS group serum TNF-α increased from 12 to 24 h (p = 0.039) and serum IL-10 decreased over time. Both CG and SS groups exhibited increased IL-6/IL-10 ratio (p = 0.040). From 12 to 24 h animals from FO group showed decreased serum IL-1 (p < 0.001), IL-4 (p < 0.002) and IL-6 (p = 0.050), and a trend towards increased IL-10 (p = 0.060). All experimental groups showed a trend towards increased PGE2 and decreased LTB4 in the lung at 24 compared with 12 hConclusion: parenteral infusion of FOLE for 48 h before the induction of experimental AP appears to favorably influence the cytokine response without affecting lung eicosanoids at the time points measured. The use of FOLE to prevent and treat AP following major surgery needs to be further explore

Revealing the NIR triggered chemotherapy therapeutic window of magnetic and thermoresponsive nanogels

The combination of magnetic nanoparticles and thermoresponsive nanogels represents an appealing strategy for the development of theranostic probes. These hybrid nanocarriers present several advantages such as outstanding properties for guided therapy, magnetic resonance imaging, and triggered release of encapsulated cargoes. Most magnetic thermoresponsive nanogels are built with strategies that comprise a physical interaction of particles with the polymeric network or the covalent attachment of a single particle to the linear polymer. Herein, we report a facile synthetic approach for the synthesis of magnetic and thermoresponsive nanogels that allows the controlled incorporation of multiple superparamagnetic inorganic cores as covalent cross linkers. An ultrasonication assisted precipitation polymerization afforded nanogels with sizes in the nanometric range and similar magnetization and light transduction properties compared to the discrete magnetic nanoparticles. The theranostic capability of these nanocarriers was further investigated both in vitro and in vivo. In vivo experiments demonstrated the capacity of these materials as nanocarriers for near infrared NIR triggered chemotherapy and highlighted the relevance of the correct concentration dose in this antitumoral modality to achieve a superior therapeutic efficac

Juveniles and children who sexually abuse A guide to risk assessment

SIGLEAvailable from British Library Document Supply Centre-DSC:q97/23781 / BLDSC - British Library Document Supply CentreGBUnited Kingdo

A Global analysis of water and nitrogen relationships between mistletoes and their hosts : broad-scale tests of old and enduring hypotheses

Mistletoes use far more water per unit carbon fixed during photosynthesis than their hosts (i.e. they have lower 'water use efficiency', WUE). The widely cited 'nitrogen-parasitism hypothesis' posits that N is the most limiting resource for mistletoes and that they use their faster transpiration rates to acquire sufficient N from the host xylem. In a rather different context, the 'mimicry hypothesis' arose in the literature suggesting that some mistletoes mimic the morphology of host leaves in order to deploy higher N leaves without suffering higher levels of herbivory. These two non-exclusive hypotheses share the common goal of trying to explain patterns of mistletoe leaf N concentration. We set out to test the generality of both hypotheses at broad geographic scale using data for 168 mistletoes-host pairs, from 39 sites, encompassing all continents except Antarctica. We drew together data from published literature and our own field data on two key plant functional traits, leaf N concentration (Nmass) and leaf carbon isotopic composition (δ¹³C) (representing long-term WUE and degree of stomatal control over photosynthesis). Key findings included (i) little or no support for the N-parasitism hypothesis: differences in mistletoe and host Nmass explained only 3% variation in differences in leaf δ¹³C, and mistletoe-host differences in leaf δ¹³C were unrelated to whether or not the hosts were N-fixers (presumed to have higher N concentration in xylem sap); (ii) partial support for the mimicry hypothesis: mimic mistletoes generally had higher Nmass when associated with N-fixing hosts (but, on non-N-fixing hosts there was no such pattern); and (iii) more broadly, mistletoes showed similar trait responses as their hosts to environmental drivers; for example, they showed similar-magnitude shifts in Nmass and δ¹³C in relation to site aridity. Contrary to current belief, our findings suggest that nitrogen is not the limiting nutrient for mistletoes, at least not the main component driving the faster transpiration rates. Our results also give insight into the evolution of mimicry in mistletoes and show, for the first time, that mistletoes are also constrained by local water availability, exhibiting clear trait adaptations to environmental gradients. By reconsidering these issues at broad geographic scale and across a large number of species, our findings substantially modify current knowledge on the ecology and physiology of mistletoes and their hosts.11 page(s

Fish oil supplementation decreases oxidative stress but does not affect platelet-activating factor bioactivity in lungs of asthmatic rats

Dietary fish oil supplementation increases the content of n-3 polyunsaturated fatty acids (PUFA) in cellular membranes. The highly unsaturated nature of n-3 PUFA could result in an enhanced lipid peroxidation in the oxidative environment characteristic of asthma. The oxidative reaction cascade culminates in an increased production of components associated to oxidative stress and of an important proinflammatory mediator platelet-activating factor (PAF)-like lipid. We evaluated the effect of fish oil supplementation in asthmatic rats upon the PAF bioactivity and parameters related to oxidative stress in the lung. Fish oil supplementation of asthmatic rats resulted in lower concentrations of nitrite (1.719 ± 0.137 vs. 2.454 ± 0.163 nmol/mL) and lipid hydroperoxide (72.190 ± 7.327 vs. 120.200 ± 11.270 nmol/mg protein). In asthmatic animals, fish oil increased the activities of superoxide dismutase (EC 1.15.1.1) (33.910 ± 2.325 vs. 24.110 ± 0.618 U/mg protein) and glutathione peroxidase (EC 1.11.1.9) (164.100 ± 31.250 vs. 12.590 ± 5.234 U/mg protein). However, fish oil did not affect PAF bioactivity in lung tissue of asthmatic rats (0.545 ± 0.098 340/380 vs. 0.669 ± 0.101 340/380 nm ratio). Considering the two-step process—oxidative stress and PAF bioactivity—fish oil exhibited a divergent action on these aspects of asthmatic inflammation, since the supplement lowered oxidative stress in the lungs of asthmatic rats, presenting an antioxidant effect, but did not affect PAF bioactivity. This suggests a dual effect of fish oil on oxidative stress and inflammation in asthma