FUNSOFT Nets: a petri-net based software process modeling language

Introduces an approach to software process modeling and analysis. It is based on describing software processes by FUNSOFT nets. FUNSOFT nets are high level Petri nets which are adapted to the application domain of software process modeling. Their semantics is defined by predicate/transition nets. That enables them to benefit from standard analysis techniques approved for predicate/transition nets

Front-end electronics for drift tubes in a high-rate environment

A front-end electronics readout for drift tubes in a high-rate environment is presented. This system allows us to encode several pieces of information (leading edge time, trailing edge time, signal charge and piled-up hits from multiple tracks) into a single readout channel that is presented to the TDC. The advantage of active baseline restoration compared to bipolar signal shaping is discussed

Rate effects in high-resolution drift chambers

The impact of high counting rates on the spatial resolution of cylindrical drift tubes is investigated in detail and the results are compared with simulations. Electronics effects and space-charge effects are quantitatively analysed. A spatial resolution of $\sigma < 80\,\mu\mathrm{m}$ can be achieved even at rates as high as 1500\,Hz/cm wire length (300\,kHz per wire)

Resolution limits of drift tubes

Measurements of the drift-tube response to charged particle tracks are compared with a complete simulation. The measured resolution of typically 80\,$\mu$m agrees well with the simulation and allows the individual factors limiting the resolution such as diffusion, charge deposit fluctuations, gas gain fluctuations and signal processing to be studied. The results with respect to the dependence of the drift chamber resolution on gas gain, gas pressure and electronics parameters are reported

Dependence of Drift Tube Performance on the Anode Wire Diameter

Cylindrical pressurized drift tubes with different anode wire diameters wereoperated in a 170~GeV muon test beam. The dependences of spatialresolution, efficiency and streamer probability on the anode wirediameter were measured. The resolution measurements are compared with a simulation

Bestimmung der Haftfestigkeit von aufgedampften, metallischen Dickschichten auf Polymersubstrat

Inaktivkomponenten in der Batterieherstellung, wie z. B. Stromsammler, Separator oder die Kontaktierungstaps rücken zunehmend in den Fokus der Forschung. Der Wechsel zu leichteren und günstigeren Materialien ist Gegenstand aktueller Forschungsarbeiten. In diesem Zusammenhang wird auch das Potential von Verbundstromkollektoren näher betrachtet. Dabei handelt es sich um Polymerfolien, die beidseitig mit 0,5 µm bis 1,5 µm dicken Aluminium- oder Kupferschichten metallisiert sind. Als Verbundmaterial müssen dabei im Vergleich zu konventionellen, metallischen Stromkollektoren zusätzliche Materialeigenschaften betrachtet werden. Dazu gehört vor allem die Haftfestigkeit der metallischen Beschichtungen auf den Folien. Es muss ausgeschlossen werden, dass durch wechselnde mechanische Beanspruchungen oder chemische Wechselwirkungen (z.B. mit dem Elektrolyten) in der Li-Ionen-Batteriezelle Delaminationen auftreten und sich die Metallisierung ablöst. Dazu ist eine quantitative Methode zur Bestimmung der Haftfestigkeit notwendig. Nur so kann eine Korrelation zwischen der Haftfestigkeit und dem Verhalten in der Zelle hergestellt werden. Bisherige Versuchsmethoden decken den Anwendungsfall von beidseitig metallisierten Polymersubstraten als Stromkollektorfolie jedoch nicht ab. Aus diesem Grund werden in dieser Studie Prüfverfahren zur Bestimmung der Haftfestigkeit, die bereits in Normen spezifiziert werden, zur Bewertung der Haftfestigkeiten der Verbundfolien adaptiert und bewertet. Die betrachteten Verfahren umfassen Schälversuche, Stirnabzugs- und Zugschertests, welche hinsichtlich ihrer Eignung zur Beurteilung der Haftfestigkeit von Verbundstromkollektoren evaluiert werden. Dabei werden Verbundfolien mit unterschiedlicher Schicht- sowie Substratdicke und variierendem Beschichtungsmaterial berücksichtigt, sodass die Sensitivität der Verfahren zur Bestimmung der Haftfestigkeit aufgelöst und darauf aufbauend deren Eignung zur Charakterisierung der Verbundfolien bewertet werden kann

Targeted DamID reveals differential binding of mammalian pluripotency factors.

The precise control of gene expression by transcription factor networks is crucial to organismal development. The predominant approach for mapping transcription factor-chromatin interactions has been chromatin immunoprecipitation (ChIP). However, ChIP requires a large number of homogeneous cells and antisera with high specificity. A second approach, DamID, has the drawback that high levels of Dam methylase are toxic. Here, we modify our targeted DamID approach (TaDa) to enable cell type-specific expression in mammalian systems, generating an inducible system (mammalian TaDa or MaTaDa) to identify genome-wide protein/DNA interactions in 100 to 1000 times fewer cells than ChIP-based approaches. We mapped the binding sites of two key pluripotency factors, OCT4 and PRDM14, in mouse embryonic stem cells, epiblast-like cells and primordial germ cell-like cells (PGCLCs). PGCLCs are an important system for elucidating primordial germ cell development in mice. We monitored PRDM14 binding during the specification of PGCLCs, identifying direct targets of PRDM14 that are key to understanding its crucial role in PGCLC development. We show that MaTaDa is a sensitive and accurate method for assessing cell type-specific transcription factor binding in limited numbers of cells

Specification of human germ cell fate with enhanced progression capability supported by hindgut organoids

Human primordial germ cells (hPGCs), the precursors of sperm and eggs, are specified during weeks 2-3 after fertilization. Few studies on ex vivo and in vitro cultured human embryos reported plausible hPGCs on embryonic day (E) 12-13 and in an E16-17 gastrulating embryo. In vitro, hPGC-like cells (hPGCLCs) can be specified from the intermediary pluripotent stage or peri-gastrulation precursors. Here, we explore the broad spectrum of hPGCLC precursors and how different precursors impact hPGCLC development. We show that resetting precursors can give rise to hPGCLCs (rhPGCLCs) in response to BMP. Strikingly, rhPGCLCs co-cultured with human hindgut organoids progress at a pace reminiscent of in vivo hPGC devel-opment, unlike those derived from peri-gastrulation precursors. Moreover, rhPGCLC specification depends on both EOMES and TBXT, not just on EOMES as for peri-gastrulation hPGCLCs. Importantly, our study pro-vides the foundation for developing efficient in vitro models of human gametogenesis.Peer reviewe

A critical role of PRDM14 in human primordial germ cell fate revealed by inducible degrons

Funder: Wellcome Trust (Wellcome); doi: https://doi.org/10.13039/100004440Funder: University of Cambridge | Churchill College, University of Cambridge; doi: https://doi.org/10.13039/501100000742Abstract: PRDM14 is a crucial regulator of mouse primordial germ cells (mPGCs), epigenetic reprogramming and pluripotency, but its role in the evolutionarily divergent regulatory network of human PGCs (hPGCs) remains unclear. Besides, a previous knockdown study indicated that PRDM14 might be dispensable for human germ cell fate. Here, we decided to use inducible degrons for a more rapid and comprehensive PRDM14 depletion. We show that PRDM14 loss results in significantly reduced specification efficiency and an aberrant transcriptome of hPGC-like cells (hPGCLCs) obtained in vitro from human embryonic stem cells (hESCs). Chromatin immunoprecipitation and transcriptomic analyses suggest that PRDM14 cooperates with TFAP2C and BLIMP1 to upregulate germ cell and pluripotency genes, while repressing WNT signalling and somatic markers. Notably, PRDM14 targets are not conserved between mouse and human, emphasising the divergent molecular mechanisms of PGC specification. The effectiveness of degrons for acute protein depletion is widely applicable in various developmental contexts