54 research outputs found
First description of pestivirus disease in Rupicapra pyrenaica pyrenaica
Understanding the circulation of pestiviruses in wild ungulates is potentially important to explain variations
in the number of animals in these species, and to implement pestivirus control programs in
domestic animals. In 2002 in the French Pyrenees, symptoms of amyotrophy and weight loss, associated
with bilateral alopecia with hairless and highly pigmented areas on the nose, around the eyes and
the ear margins were found in 8 Pyrenean chamois (Rupicapra pyrenaica pyrenaica) between 1 and 9
years old, 6 of which had been captured alive and 2 were found dead. These lesions were uncharacteristic.
The intensity of abomasal or lung parasitism varied from one animal to the other. Pestiviruses
were isolated in all 6 animals captured alive, but no anti-NS2/3 antibodies were found. Many questions
remain on the transitory or persistent nature of the infection, and on the conditions of viral transmission
within the Rupicapra genus.Comprendre la circulation de
pestivirus chez les ongulés sauvages est potentiellement important pour expliquer les
variations d'effectifs dans ces espèces et pour réaliser les programmes de contrôle des
pestiviroses atteignant les animaux domestiques. En 2002 dans les Pyrénées ariégeoises, des
symptômes d'amyotrophie et d'amaigrissement, associés à des signes d'alopécie bilatérale,
avec des zones cutanées glabres et fortement pigmentées sur le chanfrein, le pourtour des
yeux et les marges auriculaires ont été observés sur 8 isards (Rupicapra pyrenaica
pyrenaica) âgés de 1 à 9 ans, dont 6 avaient été capturés vivants et 2 trouvés morts. Les
lésions étaient peu caractéristiques. L'intensité du parasitisme abomasal ou pulmonaire
variait d'un individu à l'autre. Un pestivirus a été mis en évidence sur les 6 animaux
capturés vivants et un des deux récupérés morts (7 cas sur 8), mais aucun anticorps dirigé
contre la protéine NS2/3 n'a été trouvé. De nombreuses questions persistent sur la nature
transitoire ou persistante de l'infection et sur les modalités de transmission au sein du
genre Rupicapra
Novel catalytically active pd/Ru bimetallic nanoparticles synthesized by Bacillus benzeovorans
This work was supported by a UK Commonwealth scholarship to JBO. BK was supported by the Petroleum Technology Development Funds (PTDF) of Nigeria. The project was funded by NERC grant NE/L014076/1 to LEM. The Science City Photoemission Facility used in this research was funded through the Science Cities Advanced Materials Project 1: Creating and Characterizing Next Generation of Advanced Materials with support from AWM and ERDF funds. The microscopy work was conducted in the “Laboratorio de Microscopias Avanzadas” at “Instituto de Nanociencia de Aragon - Universidad de Zaragoza” Spain. The authors acknowledge the LMA-INA for offering access to their instruments and expertise.Bacillus benzeovorans assisted and supported growth of ruthenium (bio-Ru) and palladium/ruthenium (bio-Pd@Ru) core@shell nanoparticles (NPs) as bio-derived catalysts. Characterization of the bio-NPs using various electron microscopy techniques and high-angle annular dark field (HAADF) analysis confirmed two NP populations (1–2 nm and 5–8 nm), with core@shells in the latter. The Pd/Ru NP lattice fringes, 0.231 nm, corresponded to the (110) plane of RuO2. While surface characterization using X-ray photoelectron spectroscopy (XPS) showed the presence of Pd(0), Pd(II), Ru(III) and Ru(VI), X-ray absorption (XAS) studies of the bulk material confirmed the Pd speciation (Pd(0) and Pd(II)- corresponding to PdO), and identified Ru as Ru(III) and Ru(IV). The absence of Ru–Ru or Ru–Pd peaks indicated Ru only exists in oxide forms (RuO2 and RuOH), which are surface-localized. X ray diffraction (XRD) patterns did not identify Pd-Ru alloying. Preliminary catalytic studies explored the conversion of 5-hydroxymethyl furfural (5-HMF) to the fuel precursor 2,5-dimethyl furan (2,5-DMF). Both high-loading (9.7 wt.% Pd, 6 wt.% Ru) and low-loading (2.4 wt.% Pd, 2 wt.% Ru) bio-derived catalysts demonstrated high conversion efficiencies (~95%) and selectivity of ~63% (~20% better than bio-Ru NPs) and 58%, respectively. These materials show promising future scope as efficient low-cost biofuel catalysts.Funded by NERC grant NE/L014076/
Biosynthesis of Platinum Nanoparticles by Escherichia coli MC4100: Can Such Nanoparticles Exhibit Intrinsic Surface Enantioselectivity?
The biomanufacture of two types of platinum bionanoparticle (bioNP) using Escherichia coli MC4100(1% and 20% by mass metal loading) together with a method for both liberating the nanoparticles (NPs) from the bacterial layer and their subsequent critical cleaning is reported. The possibility of an enantiomeric excess of chiral kink sites forming on the surface of the Pt nanoparticles produced by the bacteria was investigated using the electrooxidation of d- and l-glucose as the chiral probe. Transmission electron microscopy revealed that the Pt bioNPs (after recovery and cleaning) were typically 2.3 ± 0.7 nm (1% loading) and 4.5 ± 0.7 nm (20% loading) in diameter. The d- and l-glucose electrooxidation measurements did not give rise to any chiral response using either of the Pt bioNPs types but did display differing CV profiles. This suggested that the overall surface morphology of each bioNP could be controlled by the degree of metal loading but that no enantiomeric excess of intrinsically chiral surface kink sites was present
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