Entangled maximal mixings in U_PMNS=U_l^dagger U_nu, and a connection to complex mass textures

We discuss two different configurations of U_PMNS=U_l^dagger U_nu with maximal mixings in both U_l and U_nu. The non-maximal mixing angles are assumed to be small, which means that they can be expanded in. Since we are particularly interested in the implications for CP violation, we fully take into account complex phases. We demonstrate that one possibility leads to intrinsically large theta_13 and strong deviations from maximal mixings. The other possibility is generically close to tri-bimaximal mixing, and allows for large CP violation. We demonstrate how the determination of the theta_23 octant and the precision measurement of delta_CP could discriminate among different qualitative sub-cases. In order to constrain the unphysical and observable phases even further, we relate our configurations to complex mass matrix textures. In particular, we focus on phase patterns which could be generated by powers of a single complex quantity eta=theta_C exp(i Phi), which can be motivated by Froggatt-Nielsen-like models. For example, it turns out that in all of the discussed cases, one of the Majorana phases is proportional to Phi to leading order. In the entire study, we encounter three different classes of sum rules, which we systematically classify.Comment: 27 pages, 6 tables, 1 figure. Shortened version to appear in Phys. Rev.

Expressionsanalyse des ephrin-/ Eph-Systems im frontalen Gehirn der Maus während der embryonalen und postnatalen Entwicklung

Während der Entwicklung des Gehirns vollziehen sich verschiedene, die Morphogenese beeinflussende Prozesse, die zur Ausbildung eines funktionsfähigen, verschalteten Gehirns führen. Die Expressionsanalyse des gesamten ephrin-/ Eph-Systems untersuchte mit Hilfe der In-situ-Hybridisierung an konsekutiven koronalen Kryostatschnitten des Vorderhirns der Maus die räumliche Verteilung der Gen-Transkripte in den Regionen Kortex, ventrales Telenzephalon und dorsaler Thalamus. Hierbei wurden die Altersstadien E14, E16, E18, P6 und P28 ausgewählt, um durch den zeitlichen Verlauf der Genexpression einen Zusammenhang zu zeitlich eng begrenzten entwicklungsbiologischen Prozessen wie Proliferation, Migration und Axonlenkung herzustellen

Label-free and spike-in standard-free mass spectrometry in the proteomic analysis of plasma membrane proteins and membrane-associated protein networks

Mass spectrometry is the primary technology of proteomics. For the analysis of complex proteomes, protein identities and quantities are inferred from their peptides that are generated by cleaving all proteins with the endopeptidase trypsin. But there is one major disadvantage that is due to biophysical differences, different peptides cause different intensities. Miscellaneous approaches have been developed to circumvent this problem based on the chemical or metabolic introduction of heavy stable isotopes. This enables to monitor protein abundance differences of two or more samples on the same tryptic peptides that differ in mass only. Absolute quantification can be achieved similar by spiking-in synthetic isotopical labeled counterparts of a sample’s tryptic peptides. However, labeling technics suffer from high prices, introduced biases, need for extensive manual control, laborious implementation and implementation restrictions. Therefore, a multiplicity of label-free approaches have been developed that profit from instrumental improvements targeting reliability of identifications and reproducibility of quantitative values. No extensive systematic comparison of label-free quantitative parameters has been published so far presumably because of the laborious implementation. An analysis of primary label-free parameters and associated normalization methods is presented here that compares dynamic and linear ranges and accuracies in the estimation of protein amounts. This facilitated the establishment of label-free procedures addressing three fundamental questions in proteomics: what is a sample’s composition, are proteins that share a specific property enriched and what are the differences between two (or more) samples. A new mathematic model is presented that defines and elucidates enrichment. The procedures were applied first to analyze and compare stem cell plasma membrane proteomes. This is an ambitious model for proteomics because of only small amounts of arduous to analyze, partial hydrophobic proteins in a complex proteomic and chemical background. It is of scientific relevance, as membrane proteins are the cell’s communication interface that enable cell type specific processes and hence can be used to define, isolate and quantify those. The success of cell surface proteome enrichment, the quantitative composition of the proteome and the proteomic difference between stem cells isolated from the dental pulp and cultivated in different media is shown. Secondly, the procedures were applied to the analysis of transient protein networks that assemble onto proteo-liposomes in a newly designed recruitment assay that fully recapitulates membrane sorting as seen in vivo. All transmembrane proteins need to be trafficked to other organelles’ membranes by vesicular trafficking. Sorting signals within the cytosolic regions of the protein cargos trigger the formation of trafficking complexes around those. The transient membrane complexes additionally recognize organelle or organelle-domain specific membrane lipids, such as phosphatidylinositol phosphates. Different trafficking ways are characterized by different trafficking complexes. The elucidation of trafficking complexes that form around a transmembrane protein of interest discloses its trafficking routes and involved signaling processes. The synthetic proteo-liposomes were prepared from chemically defined lipids and heterologous expressed cytosolic domains of type I or type II membrane receptors. The proteomic analyses of such samples are challenging because of huge proteomic backgrounds of proteins binding to the liposomes irrespective of the receptor and relatively small amounts and numbers of receptor-specific binders. Though the basic idea is to elucidate sorting machineries and study membrane trafficking processes, such experiments are untargeted and miscellaneous discoveries were achieved. We elucidated that the apical determinant crumbs 2 is a cargo of the retromer complex. This revealed a fameless level of control for the establishment of cell polarity. We found retromer along with the adapter complexes AP 4 and AP 5 trafficking the beta amyloid precursor protein APP. This confirmed recent publications and yielded new insights. Moreover, many more proteins and complexes appeared to associate with the cytosolic part of APP (AICD) in a membrane context-dependent or -independent manner. Among those, some were so far unknown to interact with AICD, like mTORC1 and the PIKFyve complex

Cryptographic Vulnerabilities and Other Shortcomings of the Nextcloud Server Side Encryption as implemented by the Default Encryption Module

Nextcloud provides a server side encryption feature that is implemented by the Default Encryption Module. This paper presents cryptographic vulnerabilities that existed within the Default Encryption Module as well as other shortcomings that still need to be addressed. The vulnerabilities allowed an attacker to break the provided confidentiality and integrity protection guarantees. There is a high risk that ownCloud also contains some of the issues presented in this paper as it still has cryptographic code in common with Nextcloud

Experimentelle Untersuchungen zur Validierung zähmodifizierter Klebverbindungen bei der Anwendung von HAPs

Im Umfang dieser Versuchsreihe wird die zähmodifizierte Klebverbindungen für die Luftfahrt und insbesondere für HAPs (High Altitude Plattform) untersucht. Ein Aspekt, welcher erschlossen werden soll ist die Einflussnahme auf die Klebfestigkeit durch Umwelteinflüsse. Dazu werden ausgewählte Temperaturen aus dem luftfahrttypischen Temperaturbereich von -55 °C bis 80 °C untersucht sowie eine andauernde feucht-warme Umgebung. Des Weiteren soll die zähmodifizierte Klebverbindung auf Aluminiumfügeteile übertragen werden, um einerseits die Funktionalität des Surface Toughening Konzeptes an anderen Materialen zu bestätigen und andererseits diese Klebmethode für die allgemeine Luftfahrt zu ermöglichen. Im Zuge dessen wird zusätzlich die Klebfläche untersucht, um das optimale Verhältnis von Klebfläche zu Klebfestigkeit zu prüfen. Als letzten Punkt werden Untersuchungen zu Reparaturmethoden durchgeführt, damit in Zukunft eine gute Patch-Variante für fehlerhafte oder ausbesserungsbedürftige Stellen geboten werden kann

Experimentelle Untersuchungen zum Einfluss von Umweltbedingungen auf zähmodifizierte Klebverbindungen bei Faserverbundwerkstoffen

In dieser Arbeit wird das Konzept der zähmodifizierten Klebverbindung bei Überlappungsklebungen für die Luftfahrt untersucht. Der Kerninhalt besteht in dem Erstellen von Überlappungsklebungen aus kohlenstofffaserverstärktem Kunststoff. Zur Zähmodifizierung werden Kunststoffstreifen in die Klebverbindung eingebracht. Als zähmodifizierender Werkstoff soll neben dem bisher untersuchten Polyvenylidenfluorid (PVDF) auch Polyetheretherkethon (PEEK) betrachtet werden. Die zähmodifizierten Klebverbindungen werden durch einen Zugscherversuch geprüft und mittels Bildkorrelation ausgewertet. Ein Erhöhen der Steifigkeit des zähmodifizierenden Werkstoffs sowie der Einfluss von Feuchtigkeit bewirkt eine Festigkeitsminderung der Klebverbindung. Lediglich bei der Verwendung des steiferen PEEKs führt eine erhöhte Feuchtigkeit zu einer Festigkeitssteigerung und einer homogenen Klebverbindung. Eine zähmodifizierte Klebverbindung mit PVDF und einem kaltaushärtenden Klebstoff erzielt eine Festigkeitssteigerung von 120%. Durch den niedrigtemperierten Klebprozess wird eine festigkeitsmindernde Eigenspannung im zähmodifizierten Material vermieden

Perturbing exactly tri-bimaximal neutrino mixings with charged lepton mass matrices

We study perturbations of exactly tri-bimaximal neutrino mixings under the assumption that they are coming solely from the charged lepton mass matrix. This may be plausible in scenarios where the mass generation mechanisms of neutrinos and charged leptons/quarks have a different origin. As a working hypothesis, we assume mass textures which may be generated by the Froggatt-Nielsen mechanism for the charged lepton and quark sectors, which generically leads to strong hierarchies, whereas the neutrino sector is exactly tri-bimaximal with a mild (normal) hierarchy. We find that in this approach, deviations from maximal atmospheric mixing can be introduced without affecting theta_13 and theta_12, whereas a deviation of theta_13 or theta_12 from its tri-bimaximal value will inevitably lead to a similar-sized deviation of the other parameter. Therefore, the already very precise knowledge of theta_12 points towards small sin^2(2 theta_13) <= 0.01. The magnitude of this deviation can be controlled by the specific form of the charged lepton texture.Comment: 13 pages, 9 figures; matches published version, changes in notatio