Development of a pig jejunal explant culture for studying the gastrointestinal toxicity of the mycotoxin deoxynivalenol: histopathological analysis

The digestive tract is a target for the mycotoxin deoxynivalenol (DON), a major cereals grain contaminant of public health concern in Europe and North America. Pig, the most sensitive species to DON toxicity, can be regarded as the most relevant animal model for studying the intestinal effects of DON. A pig jejunal explants culture was developed to assess short-term effects of DON. In a first step, jejunal explants from 9-13 week-old and from 4-5 week-old pigs were cultured in vitro for up to 8 hours. Explants from younger animals were better preserved after 8 hours, as assessed by morphological scores and by villi lengths. In a second step, dose-related alterations of the jejunal tissue were observed, including shortened and coalescent villi, lysis of enterocytes, oedema. After 4h of DON exposure of explants from 4-5 week-old pigs, a no-effect concentration level of 1 µM was estimated (corresponding to diet contaminated with 0.3 mg DON/kg) based on morphological scores, and of 0.2 µM based on villi lengths. In conclusion, our data indicate that pig intestinal explants represent a relevant and sensitive model to investigate the effects of food contaminants

Hydrogen embrittlement susceptibility of a high strength steel X80

The present paper deals with hydrogen embrittlement (HE) susceptibility of a high strength steel grade (X80). The respective implication of different hydrogen populations, i.e. adsorbed, dissolved in interstitial sites, trapped on dislocations and/or microstructural elements on the associated embrittlement mechanisms has been addressed through mechanical testing in high pressure of hydrogen gas at room temperature. Tensile tests at various strain rates and hydrogen pressures have been carried out. Moreover, changes of gas (hydrogen or nitrogen) during loading have been imposed in order to get critical experiments able to discriminate among the potential hydrogen embrittlement mechanisms already proposed in the literature. The results of these tests have shown that hydrogen induces several kind of damages including decohesion along ferrite/pearlite interfaces and microcracks initiations on the specimens external surface. It is shown that decohesion is not critical under the loading paths used in the present study. On the contrary, it appears that the external microcracks initiation, followed by a quasi-cleavage fracture, is responsible for the premature failure of the material in high pressure of hydrogen gas. These experimental results have been further discussed by modeling hydrogen diffusion in order to identify hydrogen populations (adsorbed, diffusible or trapped) involved in HE. It was then demonstrated that adsorbed and near surface diffusible hydrogen are mainly responsible for embrittlement

Dipole-dipole interaction between orthogonal dipole moments in time-dependent geometries

In two nearby atoms, the dipole-dipole interaction can couple transitions with orthogonal dipole moments. This orthogonal coupling accounts for a number of interesting effects, but strongly depends on the geometry of the setup. Here, we discuss several setups of interest where the geometry is not fixed, such as particles in a trap or gases, by averaging over different sets of geometries. Two averaging methods are compared. In the first method, it is assumed that the internal electronic evolution is much faster than the change of geometry, whereas in the second, it is vice versa. We find that the orthogonal coupling typically survives even extensive averaging over different geometries, albeit with qualitatively different results for the two averaging methods. Typically, one- and two-dimensional averaging ranges modelling, e.g., low-dimensional gases, turn out to be the most promising model systems.Comment: 11 pages, 14 figure

Henri Temianka Correspondence; (buckley)

This collection contains material pertaining to the life, career, and activities of Henri Temianka, violin virtuoso, conductor, music teacher, and author. Materials include correspondence, concert programs and flyers, music scores, photographs, and books.https://digitalcommons.chapman.edu/temianka_correspondence/1512/thumbnail.jp

The impact of the grazing animal on phosphorus, nitrogen, potassium and suspended solids loss from grazed pastures, Part A

Teagasc wishes to acknowledge the support of the Environmental Research Technological Development and Innovation (ERTDI) Programme under the Productive Sector Operational Programme which was financed by the Irish Government under the National Development Plan 2000-2006.End of project reportIn Ireland 90% of the 4.2 million ha of farmland is grassland. Phosphorus deficiency limited grassland production in Ireland and this was corrected by chemical fertiliser use in the 1960s and 1970s. The increased inputs of fertilisers led to increased intensification of grassland with a doubling of grass yield and of grazing animal numbers, from about 3 million to over 6 million livestock units. There is little information on relative contribution of increased chemical fertiliser use compared to increased grazing animal numbers on phosphorus loss to water. The main objective of this study was to obtain information on nutrient loss, particularly phosphorus, in overland flow from cut and grazed grassland plots, with a range of soil test phosphorus levels over three years and implications.Environmental Protection Agenc