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Several established models in human and veterinary medicine exist to evaluate an individual health or disease status. Many of these seem unsuitable for further epidemiological research aimed at discovering underlying influential factors. As a case example for score development and choice, the present study analyses different approaches to scoring the foot health of Asian elephants (Elephas maximus) living in European facilities. Sum scores with varying degree of detail, and without or with a weighting method, were compared using descriptive statistics, ie kurtosis, skewness, Shannon entropy, total redundancy, their maximum and their actual ranges. With increasing score complexity, a higher level of differentiation was reached. In parallel, the distribution of score frequencies in the population shifted systematically: with the least complex scoring model the pattern indicated a severely unhealthy population with an opposite skew to a hypothetically healthy population, whereas the most complex scoring model indicated a mildly affected population with a skew corresponding to that expected for a healthy population. We propose the latter, in the form of the Particularised Severity Score (ParSev), which accounts for every nail and pad individually and weights the sub-scores by squaring, as the most relevant score for further investigations, either in assessing changes within an elephant population over time, or correlating foot health in epidemiological studies to potentially influencing factors. Our results emphasise the relevance of choosing appropriate scoring models for welfare-associated evaluations, due to implications for the applicability as well as the perceived welfare status of the test population.
Growing evidence suggests that soluble amyloid-beta (Abeta) peptides play a pivotal role in Alzheimer’s disease(AD) pathogenesis by mediating synaptotoxic effects particularly at early disease stages.
We quantified the effects of different order Abeta assemblies on spontaneous firing dynamics ofneuronal networks cultured on multielectrode arrays ('neurochips”) as a read-out. We used naturally secreted, stable and conformationally highly homogenous Abeta monomers, dimers, and a mixture of different low-noligomers, derived from permanently transfected cell lines.
Abeta dimers promoted a dose-dependent suppression of overall activity and network synchrony and altered the burst structure already in the low picomolar dose range. By contrast, Abeta monomers exhibited no effect on overall activity, but only a slight effect on burst structure and a moderate effect on network synchrony. A yet different response pattern was seen for a mixture of various low-n Abeta oligomers. Thus, multiparametric assessment of electrical activity changes on neurochips revealed characteristic signatures of the network response for the different Abeta assemblies. Since alterations of Network function likely occur in initial disease stages, these results confirm the pivotal role of Abeta dimers in early AD pathogenesis.
Neurochip recordings of toxic dimeric Abeta species may serve as a valuable diagnostic read-out in early AD and may also be applicable for future testing of drugs, antibodies, or small molecules aiming at Abeta dimers.
Aluminum films deposited on silicon with MOCVD methods generally exhibit a high surface roughness due to the hindered nucleation. To decrease the nucleation barrier a pretreat-ment of the wafer with TiCl4 vapor as a chemical activator is commonly suggested.
This work examines the influence of a rf hydrogen plasma on the nucleation of aluminum onSi and SiO2 using TMAA as precursor.
Atomic force microscopy (AFM) was used to determine the surface roughnesses and crystallite sizes of the aluminum deposits. Without plasma activation the nucleation barrier on Si(111) is substantially higher than on oxidized Si and therefore the pretreatment of the wafer plays an important role. The hydrogen plasma causes a substantial increase of the nucleus density leading to deposits with lower surface roughnesses compared to conventionalMOCVD aluminum. The influence of the substrate on the nucleation is almost “switched off” by the plasma activation and the grain sizes of Al on Si (111) and SiO2 differ only slightly. Relatively smooth films with a resistivity of 2.7 μΩcm are obtainable by employing a plasma activated nucleation step followed by a thermal MOCVD process. The increased nucleation rate is discussed in terms of kinetic effects of plasma activation.
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