Competition between Ferrimagnetism and Magnetic Frustration in Zinc Substituted YBaFe4O7

The substitution of zinc for iron in YBaFe4O7 has allowed the oxide series YBaFe4-xZnxO7, with 0.40 < x < 1.50, belonging to the "114" structural family to be synthesized. These oxides crystallize in the hexagonal symmetry (P63mc), as opposed to the cubic symmetry (F-43m) of YBaFe4O7. Importantly, the d.c. magnetization shows that the zinc substitution induces ferrimagnetism, in contrast to the spin glass behaviour of YBaFe4O7. Moreover, a.c. susceptibility measurements demonstrate that concomitantly these oxides exhibit a spin glass or a cluster glass behaviour, which increases at the expense of ferrimagnetism, as the zinc content is increased. This competition between ferrimagnetism and magnetic frustration is interpreted in terms of lifting of the geometric frustration, inducing the magnetic ordering, and of cationic disordering, which favours the glassy state.Comment: 24 pages, 10 figure

Exploration of Long-Chain Vitamin E Metabolites for the Discovery of a Highly Potent, Orally Effective, and Metabolically Stable 5-LOX Inhibitor that Limits Inflammation.

Endogenous long-chain metabolites of vitamin E (LCMs) mediate immune functions by targeting 5-lipoxygenase (5-LOX) and increasing the systemic concentrations of resolvin E3, a specialized proresolving lipid mediator. SAR studies on semisynthesized analogues highlight α-amplexichromanol (27a), which allosterically inhibits 5-LOX, being considerably more potent than endogenous LCMs in human primary immune cells and blood. Other enzymes within lipid mediator biosynthesis were not substantially inhibited, except for microsomal prostaglandin E2 synthase-1. Compound 27a is metabolized by sulfation and β-oxidation in human liver-on-chips and exhibits superior metabolic stability in mice over LCMs. Pharmacokinetic studies show distribution of 27a from plasma to the inflamed peritoneal cavity and lung. In parallel, 5-LOX-derived leukotriene levels decrease, and the inflammatory reaction is suppressed in reconstructed human epidermis, murine peritonitis, and experimental asthma in mice. Our study highlights 27a as an orally active, LCM-inspired drug candidate that limits inflammation with superior potency and metabolic stability to the endogenous lead

Protection of Spanish Ibex (Capra pyrenaica) against Bluetongue Virus Serotypes 1 and 8 in a Subclinical Experimental Infection

Many wild ruminants such as Spanish ibex (Capra pyrenaica) are susceptible to Bluetongue virus (BTV) infection, which causes disease mainly in domestic sheep and cattle. Outbreaks involving either BTV serotypes 1 (BTV-1) and 8 (BTV-8) are currently challenging Europe. Inclusion of wildlife vaccination among BTV control measures should be considered in certain species. In the present study, four out of fifteen seronegative Spanish ibexes were immunized with a single dose of inactivated vaccine against BTV-1, four against BTV-8 and seven ibexes were non vaccinated controls. Seven ibexes (four vaccinated and three controls) were inoculated with each BTV serotype. Antibody and IFN-gamma responses were evaluated until 28 days after inoculation (dpi). The vaccinated ibexes showed significant (P<0.05) neutralizing antibody levels after vaccination compared to non vaccinated ibexes. The non vaccinated ibexes remained seronegative until challenge and showed neutralizing antibodies from 7 dpi. BTV RNA was detected in the blood of non vaccinated ibexes from 2 to the end of the study (28 dpi) and in target tissue samples obtained at necropsy (8 and 28 dpi). BTV-1 was successfully isolated on cell culture from blood and target tissues of non vaccinated ibexes. Clinical signs were unapparent and no gross lesions were found at necropsy. Our results show for the first time that Spanish ibex is susceptible and asymptomatic to BTV infection and also that a single dose of vaccine prevents viraemia against BTV-1 and BTV-8 replication

Coupled Fluid-Structure Simulation for Turbomachinery Blade Rows

A numerical method for the computation of aeroelasticity is presented. Although the emphasis here is on turbomachinery, the method is applicable to a wide variety of problems. A ow solver is coupled to a structural solver by use of a uid-structure interface method. The integration of the three-dimensional unsteady Navier-Stokes equations is performed in the time domain, simultaneously to the integration of a modal three-dimensional struc-tural model. The ow solution is accelerated by using a multigrid method and a parallel multiblock approach. Fluid-structure coupling is achieved by subiteration. The code is formulated to allow application to general, three-dimensional congurations with multi-ple independent structures. The capability of the code to handle rotating blade rows is demonstrated by an application to a transonic fan. I

Delineation of the population genetic structure of Culicoides imicola in East and South Africa

BACKGROUND: Culicoides imicola Kieffer, 1913 is the main vector of bluetongue virus (BTV) and African horse sickness virus (AHSV) in Sub-Saharan Africa. Understanding the population genetic structure of this midge and the nature of barriers to gene flow will lead to a deeper understanding of bluetongue epidemiology and more effective vector control in this region. METHODS: A panel of 12 DNA microsatellite markers isolated de novo and mitochondrial DNA were utilized in a study of C. imicola populations from Africa and an outlier population from the Balearic Islands. The DNA microsatellite markers and mitochondrial DNA were also used to examine a population of closely related C. bolitinos Meiswinkel midges. RESULTS: The microsatellite data suggest gene flow between Kenya and south-west Indian Ocean Islands exist while a restricted gene flow between Kenya and South Africa C. imicola populations occurs. Genetic distance correlated with geographic distance by Mantel test. The mitochondrial DNA analysis results imply that the C. imicola populations from Kenya and south-west Indian Ocean Islands (Madagascar and Mauritius) shared haplotypes while C. imicola population from South Africa possessed private haplotypes and the highest nucleotide diversity among the African populations. The Bayesian skyline plot suggested a population growth. CONCLUSIONS: The gene flow demonstrated by this study indicates a potential risk of introduction of new BTV serotypes by wind-borne infected Culicoides into the Islands. Genetic similarity between Mauritius and South Africa may be due to translocation as a result of human-induced activities; this could impact negatively on the livestock industry. The microsatellite markers isolated in this study may be utilised to study C. bolitinos, an important vector of BTV and AHSV in Africa and identify sources of future incursions. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s13071-015-1277-4) contains supplementary material, which is available to authorized users

Mechanical behaviour of glass fiber weaven UD/high fluidity PA-based polymers for automotive applications

International audienceThis experimental work addresses the mechanical behavior of weaven UD glass fiber-thermoplastic composites designed for layered materials to be used in the automotive industry. The investigation was implemented in terms of the formulation of the PA66-based thermoplastic resins, the architecture of the fibrous reinforcement (warp spacer) and the glass fiber content. Longitudinal and transverse tensile tests results demonstrate the excellent mechanical behavior of these composites, which correlates with the rheological/permeability properties and wettability behaviour. © 2016 Author(s)

Sintering mechanism and grain growth in CaCu 3 Ti 4 O 12 ceramics

In this work, a study of the densification of CaCu 3 Ti 4 O 12 (CCTO) ceramics during conventional sintering process is presented. Dilatometric study was conducted in detail to find out which diffusion mechanism is responsible for densification. Based on the shrinkage curves, it was shown that densification is mostly controlled by grain boundary diffusion. The microstructure evolution of CCTO during conventional sintering was studied through the sintering trajectory, which corresponds to a unique relationship between grain size and density. According to SEM analysis, it was shown that abnormal grain growth takes place for samples sintered at high temperature stage with density andgt;80% of the theoretical density. Finally, the Master Sintering Curve (MSC) method was also used to characterize the densification process of CCTO and estimate the apparent sintering activation energy (Q = 730 kJ mol -1 ). © 2019 Elsevier Ltd and Techna Group S.r.l

Sintering mechanism and grain growth in CaCu 3 Ti 4 O 12 ceramics

International audienceIn this work, a study of the densification of CaCu 3 Ti 4 O 12 (CCTO) ceramics during conventional sintering process is presented. Dilatometric study was conducted in detail to find out which diffusion mechanism is responsible for densification. Based on the shrinkage curves, it was shown that densification is mostly controlled by grain boundary diffusion. The microstructure evolution of CCTO during conventional sintering was studied through the sintering trajectory, which corresponds to a unique relationship between grain size and density. According to SEM analysis, it was shown that abnormal grain growth takes place for samples sintered at high temperature stage with density andgt;80% of the theoretical density. Finally, the Master Sintering Curve (MSC) method was also used to characterize the densification process of CCTO and estimate the apparent sintering activation energy (Q = 730 kJ mol -1 ). © 2019 Elsevier Ltd and Techna Group S.r.l