Grain size distribution analysis in polycrystalline LiF thin films by mathematical morphology techniques on AFM images and X-ray diffraction data

Globular and protofibrillar aβ aggregates impair neurotransmission by different mechanisms

In Alzheimer's disease, substantial evidence indicates the causative role of soluble amyloid β (Aβ) aggregates. Although a variety of Aβ assemblies have been described, the debate about their individual relevance is still ongoing. One critical issue hampering this debate is the use of different methods for the characterization of endogenous and synthetic peptide and their intrinsic limitations for distinguishing Aβ aggregates. Here, we used different protocols for the establishment of prefibrillar Aβ assemblies with varying morphologies and sizes and compared them in a head-to-head fashion. Aggregation was characterized via the monomeric peptide over time until spheroidal, protofibrillar, or fibrillar Aβ aggregates were predominant. It could be shown that a change in the ionic environment induced a structural rearrangement, which consequently confounds the delineation of a measured neurotoxicity toward a distinct Aβ assembly. Here, neuronal binding and hippocampal neurotransmission were found to be suitable to account for the synaptotoxicity to different Aβ assemblies, based on the stability of the applied Aβ aggregates in these settings. In contrast to monomeric or fibrillar Aβ, different prefibrillar Aβ aggregates targeted neurons and impaired hippocampal neurotransmission with nanomolar potency, albeit by different modalities. Spheroidal Aβ aggregates inhibited NMDAR-dependent long-term potentiation, as opposed to protofibrillar Aβ aggregates, which inhibited AMPAR-dominated basal neurotransmission. In addition, a provoked structural conversion of spheroidal to protofibrillar Aβ assemblies resulted in a time-dependent suppression of basal neurotransmission, indicative of a mechanistic switch in synaptic impairment. Thus, we emphasize the importance of addressing the metastability of prefacto characterized Aβ aggregates in assigning a biological effect.

A confident scale-space shape representation framework for cell migration detection

Automated segmentation of time-lapse images is a method to facilitate the understanding of the intricate biological progression, e.g. cancer cell migration. To address this problem, we introduce a shape representation enhancement over popular snake models in the context of confident scale-space such that a higher level of interpretation can hopefully be achieved. Our proposed system consists of a hierarchical analytic framework including feedback loops, self-adaptive and demand-adaptive adjustment, incorporating a steerable boundary detail term constraint based on multiscale B-spline interpolation. To minimize the noise interference inherited from microscopy acquisition, the coarse boundary derived from the initial segmentation with refined watershed line is coupled with microscopy compensation using the mean shift filtering. A progressive approximation is applied to achieve represented as a balance between a relief function of watershed algorithm and local minima concerning multiscale optimality, convergence and robust constraints. Experimental results show that the proposed method overcomes problems with spurious branches, arbitrary gaps, low contrast boundaries and low signal-to-noise ratio. The proposed system has the potential to serve as an automated data processing tool for cell migration applications.