Structural properties of Pb3Mn7O15 determined from high-resolution synchrotron powder diffraction

We report on the crystallographic structure of the layered compound Pb3Mn7O15. Previous analysis based on laboratory X-ray data at room temperature gave contradictory results in terms of the description of the unit cell. Motivated by recent magnetic bulk measurements of this system, we re-investigated the chemical structure with high-resolution synchrotron powder diffraction at temperatures between 15 K and 295 K. Our results show that the crystal structure of stoichiometric Pb3Mn7O15 has a pronounced 2-dimensional character and can be described in the orthorhombic space group Pnma.Comment: 6 pages, 4 figures, 2 table

Kinetics of expulsion of Haemonchus contortus from sheep and jirds after treatment with closantel

Experiments were conducted in sheep after intramuscular treatment with closantel and in jirds after oral treatment with closantel to determine when expulsion of established H. contortus commences. Expulsion starts at about 8 h in sheep and coincides with the onset of reduced motility in worms recovered from the abomasum. In jirds, expulsion starts by 2 h after treatment. Experiments also conducted in jirds showed that infective larvae are first killed by circulating closantel 3 days after infection, when blood feeding starts, and that by 8 days 80% of larvae are lost

Orientably-regular maps on twisted linear fractional groups

We present an enumeration of orientably-regular maps with automorphism group isomorphic to the twisted linear fractional group $M(q^2)$ for any odd prime power $q$

Chiral Polytopes and Suzuki Simple Groups

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Comparative in vitro effects of closantel and selected beta-ketoamide anthelmintics on a gastrointestinal nematode and vertebrate liver cells

PNU-87407 and PrNU-88509, beta-ketoamide anthelmintics that are structurally related to each other and to the salicylanilide anthelmintic closantel, exhibit different anthelmintic spectra and apparent toxicity in mammals, The basis for this differential pharmacology was examined in experiments that measured motility and adenosine triphosphate (ATP) levels in larval and adult stages of the gastrointestinal nematode, Haemonchus contortus, and in a vertebrate liver cell line and mitochondria, PNU-87407 and PNU-88509 both exhibited functional cross-resistance with closantel in larval migration assays using closantel-resistant and -sensitive isolates of H, contortus. Each compound reduced motility and,ATP levels in cultured adult H. contortus in a concentration- and time-dependent manner: however, motility was reduced more rapidly by PNU-88509, and ATP levels were reduced by lower concentrations of closantel than the beta-ketoamides. Tension recordings from segments of adult H, contortus showed that PNU-88509 induces spastic paralysis, while PNU-87407 and closantel induce flaccid paralysis of the somatic musculature. Marked differences in the actions of these compounds were also observed in the mammalian preparations. In Chang liver cells, ATP levels were reduced after 3 h exposures to greater than or equal to 0.25 mu M PNU-87407 1 mu M closantel or 10 mu M PNU-88509, Reductions in ATP caused by PNU-88509 were completely reversible, while the effects of closantel and PNU-87407; were irreversible. PNU-87407, closantel and PNU-88509 uncoupled oxidative phosphorylation in isolated rat liver mitochondria, inhibiting the respiratory control index (with glutamate or succinate as substrate) by 50% at concentrations of 0.14, 0.9 and 7.6 mu M respectively

Resistência parasitária em helmintos de eqüídeos e propostas de manejo Parasite resistance on helminths of equids and management proposal’s

Os eqüinos apresentam uma grande variedade de parasitas em sua fauna helmíntica, e algumas espécies/gêneros são de relevada importância, como: Parascaris equorum, Anoplocephala perfoliata, Oxyuris equi, Cyathostomum spp. e Strongylus spp. O controle destas infecções depende principalmente da utilização de produtos antiparasitários de forma supressiva ou estratégica e, em menor escala, de forma curativa. O tratamento supressivo é o fator mais importante na promoção da seleção de organismos resistentes, prejudicando a sustentabilidade de qualquer programa sanitário. As formas de detecção da resistência parasitária são onerosas e as mais comuns expressam resultados imprecisos. Entretanto, estas técnicas servem para monitorar a evolução e determinar os organismos envolvidos. A combinação de drogas é uma ferramenta que deve ser utilizada com muita cautela, pois esta alternativa não garante uma redução significativa de organismos resistentes aos compostos envolvidos. O objetivo deste artigo é apresentar formas de planejamento que auxiliem a melhorar a condição sanitária, o bem-estar dos animais e preserve o efeito tóxico dos produtos antiparasitários.<br>Equines harbour a variety of parasitic organisms on their helminth fauna and there are a few species/genus of interest, such as: Parascaris equorum, Anoplocephala perfoliata, Oxyuris equi, Cyathostomum spp. and Strongylus spp. The control of these infections relies mostly on the suppressive or strategic usage of antiparasitic compounds, and to a less extent on curative/salvage treatments. Suppressive treatment is the most important factor regarding the selection of resistant organisms, causing the impairment of sanitary programs. Detection methods of parasite resistance are expensive and the most common ones express variable results. Although, these techniques allow monitoring the evolution and the determination of which organisms are involved. Drug combination is a toll that should be used with caution, because it may not reduce the presence of resistant organisms to the compounds involved. The objective of this article is to demonstrate control alternatives that would contribute to sanitary management, to improve animal welfare and to preserve the toxic effect of the antiparasitic products