Robust far-field imaging by spatial coherence engineering

The degree of coherence (DOC) function that characterizes the second-order correlations at any two points in a light field is shown to provide a new degree of f...     

Validation of Tuba1a as Appropriate Internal Control for Normalization of Gene Expression Analysis during Mouse Lung Development

The expression ratio between the analysed gene and an internal control gene is the most widely used normalization method for quantitative RT-PCR (qRT-PCR) expression analysis. The ideal reference gene for a specific experiment is the one whose expression is not affected by the different experimental conditions tested. In this study, we validate the applicability of five commonly used reference genes during different stages of mouse lung development. The stability of expression of five different reference genes (Tuba1a, Actb Gapdh, Rn18S and Hist4h4) was calculated within five experimental groups using the statistical algorithm of geNorm software. Overall, Tuba1a showed the least variability in expression among the different stages of lung development, while Hist4h4 and Rn18S showed the maximum variability in their expression. Expression analysis of two lung specific markers, surfactant protein C (SftpC) and Clara cell-specific 10 kDA protein (Scgb1a1), normalized to each of the five reference genes tested here, confirmed our results and showed that incorrect reference gene choice can lead to artefacts. Moreover, a combination of two internal controls for normalization of expression analysis during lung development will increase the accuracy and reliability of results.     

The Role of Natural Polymorphic Variants of DNA Polymerase β in DNA Repair

DNA polymerase β (Polβ) is considered the main repair DNA polymerase involved in the base excision repair (BER) pathway, which plays an important part in the repair of damaged DNA bases usually resulting from alkylation or oxidation. In general, BER involves consecutive actions of DNA glycosylases, AP endonucleases, DNA polymerases, and DNA ligases. It is known that protein–protein interactions of Polβ with enzymes from the BER pathway increase the efficiency of damaged base repair in DNA. However natural single-nucleotide polymorphisms can lead to a substitution of functionally significant amino acid residues and therefore affect the catalytic activity of the enzyme and the accuracy of Polβ action. Up-to-date databases contain information about more than 8000 SNPs in the gene of Polβ. This review summarizes data on the in silico prediction of the effects of Polβ SNPs on DNA repair efficacy; available data on cancers associated with SNPs of Polβ; and experimentally tested variants of Polβ. Analysis of the literature indicates that amino acid substitutions could be important for the maintenance of the native structure of Polβ and contacts with DNA; others affect the catalytic activity of the enzyme or play a part in the precise and correct attachment of the required nucleotide triphosphate. Moreover, the amino acid substitutions in Polβ can disturb interactions with enzymes involved in BER, while the enzymatic activity of the polymorphic variant may not differ significantly from that of the wild-type enzyme. Therefore, investigation regarding the effect of Polβ natural variants occurring in the human population on enzymatic activity and protein–protein interactions is an urgent scientific task.     

Electroporation-Induced Cell Modifications Detected with THz Time-Domain Spectroscopy

Electroporation (electropermeabilization) increases the electrical conductivity of biological cell membranes and lowers transport barriers for normally impermeant materials. Molecular simulations suggest that electroporation begins with the reorganization of water and lipid head group dipoles in the phospholipid bilayer interface, driven by an externally applied electric field, and the evolution of the resulting defects into water-filled, lipid pores. The interior of the electroporated membrane thus contains water, which should provide a signature for detection of the electropermeabilized state. In this feasibility study, we use THz time-domain spectroscopy, a powerful tool for investigating biomolecular systems and their interactions with water, to detect electroporation in human cells subjected to permeabilizing pulsed electric fields (PEFs). The time-domain response of electroporated human monocytes was acquired with a commercial THz, time-domain spectrometer. For each sample, frequency spectra were calculated, and the absorption coefficient and refractive index were extracted in the frequency range between 0.2 and 1.5 THz. This analysis reveals a higher absorption of THz radiation by PEF-exposed cells, with respect to sham-exposed ones, consistent with the intrusion of water into the cell through the permeabilized membrane that is presumed to be associated with electroporation.     

MAKING VISIBLE

This article analyses recent photographic practices that make visible underlying realities faced by Western societies today as they struggle to reconcile contradictions between their policies on race, immigration and ethnicity and the quest for an integrated national identity. The main case studies are drawn from the works of Mohamed Bourouissa and Tobias Zielony. The article demonstrates how their photographic projects confront the logic of social and cultural marginalisation of the immigrant communities, which often overlaps with their spatial consignment to urban peripheries. By combining reality and fiction, symbolism and documentation, these projects offer alternatives to the modes of representation available in photojournalism, as well as re-connecting with the genre of street photography.     

Löschen im Internet – rechtlich gefordert und technisch möglich!

Die im Art. 17 der Datenschutz-Grundverordnung (DSGVO) enthaltene Regelungen für das Löschen, insbesondere die Pflicht, Dritte über die Löschanfragen zu informieren, sind mit einem hohen Aufwand für die Verantwortlichen verbunden, sodaßs sie ohne eine technische Unterstützung in der Praxis nicht umgesetzt werden können. Die zurzeit jedoch fehlenden technischen Lösungen führen zu einer Lücke zwischen den Rechtsvorschriften und den derzeitigen technischen Möglichkeiten, während die DSGVO ab Mai 2018 anzuwenden ist. Um diese Lücke zu schließen, wird im Folgenden zunächst analysiert, welche Möglichkeiten im Allgemeinen bestehen, das Löschen im Internet gemäß Art. 17 technisch umzusetzen. Anschließend wird eine Lösung für die Verteilung der Löschanfragen an die Verantwortlichen vorgestellt, das auf der Kombination der Technik mit dem Gesetz beruht und sowohl den Betroffenen als auch den Verantwortlichen ein Werkzeug zur Unterstützung des Art. 17 zur Verfügung stellt.