630 research outputs found

    Anticholinesterase activity of endemic plant extracts from Soqotra

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    A total of 30 chloroform and methanol extracts from the following endemic Soqotran plants Acridocarpus socotranus Olive, Boswellia socotranao Balf.fil, Boswellia elongata Balf. fil., Caralluma socotrana N. Br, Cephalocroton socotranus Balf.f, Croton socotranus Balf. fil.., Dendrosicycos socotrana Balf.f., Dorstenia gigas Schweinf. ex Balf. fil., Eureiandra balfourii Cogn. & Balf. fil., Kalanchoe farinaceae Balf.f, Limonium sokotranum (Vierh) Radcl. Sm), Oldenlandia pulvinata, Pulicaria diversifolia( Balf. and Pulicaria stephanocarpa Balf. were screened for their acetylcholinesterase inhibitory activity by using in vitro Ellman method at 50 and 200 μg/ml concentrations. Chloroform extracts of Croton socotranus, Boswellia socotrana, Dorstenia gigas, and Pulicaria stephanocarpa as well as methanol extracts of Eureiandra balfourii exhibited inhibitory activities higher than 50 % at concentration of 200 μg. At a concentrations of 50 μg, the chloroform extract of Croton socotranus exhibited an inhibition of 40.6 %.Key words: plant extracts, acetylcholinesterase inhibitors, Soqotra, Alzheimer’s diseas

    Post Weaning Management of Heifer Calves Impacts ADG and Feed Efficiency as Pregnant Heifers

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    Replacement heifers were developed on cornstalks (Exp. 1, 2, and 3), dry lot (Exp. 1 and 2), or winter range (Exp. 3). In Exp. 1, pregnant heifers were individually fed during mid to late gestation. Heifers developed on cornstalks were more feed efficient than heifers developed in a dry lot. In Exp. 2 and 3, pregnant heifers grazed cornstalks during mid to late gestation. Heifers developed on cornstalks gained more and were more efficient, especially compared to heifers developed in a dry lot. These data provide evidence of an adaptive response to grazing low quality forages and may be beneficial in the critical period leading up to the first calving season

    Effect of Heifer Development System on Reproduction and Subsequent Gain as a Pregnant Heifer

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    Weaned heifers grazed corn residue, upland range, or were fed 1 of 2 drylot diets differing in energy. Heifer development diets did not impact their resulting AI or final pregnancy rates. Cost per pregnant heifer was similar among treatments. A subset of AI- pregnant heifers was placed in a Calan Broadbent individual feeding system during late gestation. As a pregnant heifer, feed efficiency was not impacted by development system. These results indicate producers may utilize their most readily available and/or cost- effective feed resources with no detriment to pregnancy rates or feed efficiency as first- calf heifers

    The effect of extraction techniques on calcium concentrations and isotope ratios of marine pore water

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    Comparing two different techniques applied for the extraction of marine pore water samples from sediments, the well-established whole round (WR) method and the more recent Rhizon method, in terms of their effects on stable calcium isotope ratios in extracted pore waters, we recognize a systematic offset between the two sampling methods. Higher δ44/40Ca values are associated with lower Ca concentrations for the Rhizon sampling technique and lower δ44/40Ca values are associated with higher Ca concentrations for the corresponding WR-derived pore water samples. Models involving Rayleigh fractionation and mixing calculation suggest that the observed offset is most likely caused by a combined process of CaCO3 precipitation and ion exchange taking place during Rhizon sampling-induced CO2 degassing. Changing pressure, extraction time or extraction yield during WR pressing does not lead to a variation in δ44/40Ca, indicating that no Ca isotope fractionation takes place during the sampling of pore water. On the basis of analytical and modelling results, WR samples appear to provide δ44/40Ca values that are more representative of the ‘true’ pore water isotopic composition. While the difference between the sampling techniques is close to the present-day analytical precision of Ca isotope analysis, it may become more relevant with increasing analytical precision in the future

    Magnetic proximity effects in V/Fe superconductor/ferromagnet single bilayer revealed by waveguide-enhanced polarized neutron reflectometry

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    Polarized neutron reflectometry is used to study the magnetic proximity effect in a superconductor/ferromagnet (SC/FM) system of composition Cu(32nm)/V(40nm)/Fe(1nm)/MgO. In contrast to previous studies, here a single SC/FM bilayer, is studied and multilayer artefacts are excluded. The necessary signal enhancement is achieved by waveguide resonance, i.e. preparing the V(40nm)/Fe(1nm) SC/FM bilayer sandwiched by the highly reflective MgO substrate and Cu top layer, respectively . A new magnetic state of the system was observed at temperatures below 0.7 TC. manifested in a systematic change in the height and width of the waveguide resonance peak. Upon increasing the temperature from 0.7 TC to TC, a gradual decay of this state is observed, accompanied by a 5% growth of the diffuse scattering. According to theoretical studies, such behavior is the result of the magnetic proximity effect. Due to the presence of the thin FM layer the superconducting electrons are polarized and, as a result, near the SC/FM interface an additional magnetic layer appears in the SC with thickness comparable to ksi, the coherence length of the superconductor.Comment: Submitted to the Journal of Superconductivity and Novel Magnetism. 11 pages, 6 figures

    Impact of local knowledge endowment on employment growth in nanotechnology

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