Bildkonstruktionen bei Annibale Carracci und Caravaggio: Analyse von kunstwissenschaftlichen Datenbanken mit Hilfe skalierbarer Bildmatrizen

Der vorliegende Bericht fasst die Ergebnisse eines Projektes zur Bildkonstruktion bei Annibale Carracci und Caravaggio zusammen, in dem die von den Autoren vorgestellte Methode zur Herstellung skalierbarer Bildmatrizen einer weiteren Anwendung näher gebracht wurde

Niwaki Instead of Random Forests: Targeted Serial Sectioning Scanning Electron Microscopy With Reimaging Capabilities for Exploring Central Nervous System Cell Biology and Pathology

Ultrastructural analysis of discrete neurobiological structures by volume scanning electron microscopy (SEM) often constitutes a “needle-in-the-haystack” problem and therefore relies on sophisticated search strategies. The appropriate SEM approach for a given relocation task not only depends on the desired final image quality but also on the complexity and required accuracy of the screening process. Block-face SEM techniques like Focused Ion Beam or serial block-face SEM are “one-shot” imaging runs by nature and, thus, require precise relocation prior to acquisition. In contrast, “multi-shot” approaches conserve the sectioned tissue through the collection of serial sections onto solid support and allow reimaging. These tissue libraries generated by Array Tomography or Automated Tape Collecting Ultramicrotomy can be screened at low resolution to target high resolution SEM. This is particularly useful if a structure of interest is rare or has been predetermined by correlated light microscopy, which can assign molecular, dynamic and functional information to an ultrastructure. As such approaches require bridging mm to nm scales, they rely on tissue trimming at different stages of sample processing. Relocation is facilitated by endogenous or exogenous landmarks that are visible by several imaging modalities, combined with appropriate registration strategies that allow overlaying images of various sources. Here, we discuss the opportunities of using multi-shot serial sectioning SEM approaches, as well as suitable trimming and registration techniques, to slim down the high-resolution imaging volume to the actual structure of interest and hence facilitate ambitious targeted volume SEM projects

Large Scale Bacterial Colony Screening of Diversified FRET Biosensors

Biosensors based on Forster Resonance Energy Transfer (FRET) between fluorescent protein mutants have started to revolutionize physiology and biochemistry. However, many types of FRET biosensors show relatively small FRET changes, making measurements with these probes challenging when used under sub-optimal experimental conditions. Thus, a major effort in the field currently lies in designing new optimization strategies for these types of sensors. Here we describe procedures for optimizing FRET changes by large scale screening of mutant biosensor libraries in bacterial colonies. We describe optimization of biosensor expression, permeabilization of bacteria, software tools for analysis, and screening conditions. The procedures reported here may help in improving FRET changes in multiple suitable classes of biosensors

The Effect of Registered Student Organization Involvement on Leadership Goal Progress

This research looks at the relationship between registered student organization involvement and progress made on leadership-related goals. We surveyed 908 students following their participation in a week-long leadership development program on both their student organization involvement as well as their self-reported progress made on the leadership-related goals they created while involved in the program. We found that level of involvement (e.g. number of hours spent) in student organizations was not significantly correlated with students’ progress toward their goals. However, student organization involvement (e.g. number of registered student organizations) emerged as a small, but statistically significant, effect on students’ progress on their goals. Although statistically small, we can still conclude that student involvement is a component in moving students from “thinking about” to “making progress” on their leadership-related goals. Further research should look at which types of student organizations lead to the greatest impact on student goal progress and whether being involved in too many organizations can have a negative effect on student leadership development.Ope

Comparative monolayer investigations of surface properties of negatively charged glycosphingolipids from vertebrates (gangliosides) and invertebrates (SGL-II, lipid IV).

The surface properties of four negatively charged glycosphingolipids from vertebrates, the sialo-glycosphingolipids (=gangliosides) GM1, GD1a, GT1b and a sulfo-glycosphingolipid (=sulfatide), and of the two negatively charged glycosphingolipids from lower invertebrates, the glucurono-glycosphingolipid Lipid IV and the aminophosphono-glycosphingo-lipid SGL-II were investigated in monolayers at the air/water interface. The molecular peculiarities under investigation were surface pressure (π) and surface potential (ΔV) which are described for Lipid IV and SGL-II for the first time. The surface pressure/area isotherms of all glycosphingolipids were typical of a liquid-expanded monolayer and, with the exception of SGL-II, exhibited a phase transition to a liquid-condensed state at surface pressures above 20 mN/m. The surface potential/molecular area data found for gangliosides in the closely packed state at π=30 mN/m (GM1: ΔV = −17 mV; GD1a: ΔV = −35 mV; GT1b: ΔV = −39 mV) showed only a slight influence of the additional number of negatively charged residues. For Lipid IV, the surface behavior was very similar to GM1 both possessing one negative group per molecule, whereas in SGL-II also the surface potential data (ΔV = −173 mV) were different compared with GD1a both possessing two negative groups per molecule. The addition of Ca2+ condensed the monolayers of all glycolipids and increased the potential in the direction to more positive values, but these findings were less effective in SGL-II films. On the basis of monolayer results presented here, in biological membranes of invertebrates especially Lipid IV might play a similar role as the ganglioside GM1 in vertebrate cells