629 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

    Role of disorder when upscaling magnetocaloric Ni-Co-Mn-Al Heusler alloys from thin films to ribbons

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    Research in functional magnetic materials often employs thin films as model systems for finding new chemical compositions with promising properties. However, the scale-up of thin films towards bulk-like structures is challenging, since the material synthesis conditions are entirely different for thin films and e.g. rapid quenching methods. As one of the consequences, the type and degree of order in thin films and melt-spun ribbons are usually different, leading to different magnetic properties. In this work, using the example of magnetocaloric Ni-Co-Mn-Al melt-spun ribbons and thin films, we show that the excellent functional properties of the films can be reproduced also in ribbons, if an appropriate heat treatment is applied, that installs the right degree of order in the ribbons. We show that some chemical disorder is needed to get a pronounced and sharp martensitic transition. Increasing the order with annealing improves the magnetic properties only up to a point where selected types of disorder survive, which in turn compromise the magnetic properties. These findings allow us to understand the impact of the type and degree of disorder on the functional properties, paving the way for a faster transfer of combinatorial thin film research towards bulk-like materials for magnetic Heusler alloys

    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

    Drug Burden Index and Cognitive and Physical Function in Aged Care Residents:A Longitudinal Study

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    Objectives: Anticholinergic/antimuscarinic and sedative medications (eg, benzodiazepines) have been found to be associated with poorer cognitive and physical function and mobility impairment in older age. However, previous studies were mostly conducted among community-dwelling older individuals and had often a cross-sectional design. Accordingly, our aim was to examine longitudinal associations between cumulative exposure to anticholinergic and sedative medications and cognitive and physical function among residents from aged care homes. Design: Longitudinal study. Setting and Participants: A total of 4624 residents of Dutch aged care homes of whom data were collected between June 2005 and April 2014. Methods: Outcome measures were collected with the Long-Term Care Facilities assessment from the international Residential Assessment Instrument (interRAI-LTCF) and included the Cognitive Performance Scale, the Activities of Daily Living (ADL) Hierarchy scale, a timed 4-meter walk test, distance walked, hours of physical activity, and days being outside. Cumulative exposure to anticholinergic and sedative medications was calculated with the Drug Burden Index (DBI), a linear additive pharmacological dose-response model. Associations were examined with linear mixed models to take the potential dependence of observations into account (ie, data were collected at repeated assessment occasions of residents who were clustered in aged care homes). Analyses were adjusted for sex, age, dementia, comorbidity (neurological, psychiatric, cardiovascular, oncological, and pulmonary), fractures, depressive symptoms, and medications excluded from the DBI. Results: We observed significant longitudinal associations between a higher DBI and poorer ADLs, fewer hours of physical activity, and fewer days being outside. We found no significant longitudinal association between a higher DBI and poorer cognitive function. Conclusions and Implications: Over time, cumulative exposure to anticholinergic and sedative medications is associated with poorer physical but not cognitive function in aged care residents. Careful monitoring of aged care residents with high cumulative anticholinergic and sedative medication exposure is needed
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