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The ribosome assembly factor Nsa2 is part of the Rea1-Rsa4-Nsa2 interconnected relay on nuclear pre-60S particles that is essential for 60S ribosome biogenesis. Cryo-EM structures depict Nsa2 docked via its C-terminal &beta, barrel domain to nuclear pre-60S particles, whereas the extended N-terminus, consisting of three &alpha, helical segments, meanders between various 25S rRNA helices with the extreme N-terminus in close vicinity to the Nog1 GTPase center. Here, we tested whether this unappreciated proximity between Nsa2 and Nog1 is of functional importance. Our findings demonstrate that a conservative mutation, Nsa2 Q3N, abolished cell growth and impaired 60S biogenesis. Subsequent genetic and biochemical analyses verified that the Nsa2 N-terminus is required to target Nsa2 to early pre-60S particles. However, overexpression of the Nsa2 N-terminus abolished cytoplasmic recycling of the Nog1 GTPase, and both Nog1 and the Nsa2-N (1-58) construct, but not the respective Nsa2-N (1-58) Q3N mutant, were found arrested on late cytoplasmic pre-60S particles. These findings point to specific roles of the different Nsa2 domains for 60S ribosome biogenesis.

Ribosome biogenesis in eukaryotic cells is a highly dynamic and complex process innately linked to cell proliferation. The assembly of ribosomes is driven by a myriad of biogenesis factors that shape pre-ribosomal particles by processing and folding the ribosomal RNA and incorporating ribosomal proteins. Biochemical approaches allowed the isolation and characterization of pre-ribosomal particles from Saccharomyces cerevisiae, which lead to a spatiotemporal map of biogenesis intermediates along the path from the nucleolus to the cytoplasm. Here, we cloned almost the entire set (∼180) of ribosome biogenesis factors from the thermophilic fungus Chaetomium thermophilum in order to perform an in-depth analysis of their protein-protein interaction network as well as exploring the suitability of these thermostable proteins for structural studies. First, we performed a systematic screen, testing about 80 factors for crystallization and structure determination. Next, we performed a yeast 2-hybrid analysis and tested about 32,000 binary combinations, which identified more than 1000 protein-protein contacts between the thermophilic ribosome assembly factors. To exemplary verify several of these interactions, we performed biochemical reconstitution with the focus on the interaction network between 90S pre-ribosome factors forming the ctUTP-A and ctUTP-B modules, and the Brix-domain containing assembly factors of the pre-60S subunit. Our work provides a rich resource for biochemical reconstitution and structural analyses of the conserved ribosome assembly machinery from a eukaryotic thermophile.

Heutzutage sind eingebettete Echtzeitsysteme allgegenwärtig, beispielsweise im Automobilsektor, in der Luftfahrt, in industriellen Kontrollsystemen oder in der Heimautomatisierung. Infolge des kontinuierlich steigenden Anspruchs an die Funktionalität, nimmt die Komplexität von Software weiterhin zu. Diese Entwicklung stellt immer höhere Anforderungen an die Rechenleistung eingebetteter Systeme. Nach der Leistungssteigerung durch Multicore-Prozessoren im Desktop- und Serverbereich haben Multicore- Systeme mittlerweile Einzug in die Domäne von eingebetteten Systemen gehalten. Allerdings besitzen eingebettete Systeme zumeist zusätzliche Anforderungen aufgrund ihrer Arbeitsumgebung und des Einsatzzwecks, u. a. Bedingungen an das Zeitverhalten von Softwareanwendungen. Die vorliegende Arbeit hat zum Ziel, eine Entwicklungsplattform bereitzustellen, die eine Evaluierung von Techniken bezüglich der Kommunikation in eingebetteten Multicore-Systemen unter Berücksichtigung von Echtzeitanforderungen ermöglicht. Hierfür wurden eine mehrschichtige Softwarearchitektur und eine Kernel-Bibliothek entworfen, die im Rahmen des parMERASA Projekts exemplarisch im Automobilsektor, Luftfahrtbereich und in der Baumaschinenbranche eingesetzt wurde. Dabei wurde großes Augenmerk auf die Kommunikations- und Synchronisationsmechanismen gelegt, die eine obere Zeitschranke für Analysen der Programmausführungszeit erlauben. Zudem wurden Betriebssystemdienste, die zwischen Kernen in Multicore-Prozessoren vermitteln und speziell im Automobilbereich vorkommen, anhand zweier grundlegend verschiedener Techniken umgesetzt. Da diese Dienste zur Kommunikation und Synchronisation zwischen Prozessorkernen benötigt werden, lassen sich auf diese Weise Vor- und Nachteile beider Methoden im Bezug auf den Kommunikationsmehraufwand beurteilen. Darüber hinaus werden verschiedene Echtzeitprogrammiermodelle kurz angerissen und im Besonderen auf die Vor- und Nachteile des Logical Execution Time (LET) Modells eingegangen. Ein Nachteil dabei ist, dass die Aktualität der Daten zwischen kommunizierenden Programmteilen merklich niedriger ist als bei anderen Modellen. Das letzte Hauptkapitel dieser Arbeit befasst sich indirekt mit der Erhaltung des Datenflusses bei der Portierung von Industrieanwendungen von Singlecore- auf Multicore-Systeme unter Verwendung des LET Modells. Im Speziellen wird eine Methode vorgestellt, die den Nachteil des hohen Datenalters mindert.

Parallelization of AUTOSAR legacy software is a fundamental step to exploit the performance of multi-core electronic control units (ECUs). However, communication between runnables causes serialization and intra-task parallelization can therefore introduce large idle intervals, if a task contains a long critical path. Distributing the instructions of a runnable over cores (fine-grained parallelism) can reduce the serialization to a shorter time, but this requires an efficient and timing analyzable implementation. This paper investigates the efficiency of fine-grained parallelism for reducing the worst-case execution time in automotive applications. A pattern-supported parallelization approach is applied to extract parallelism of runnables in a structured way. Algorithmic skeletons are used to implement fine-grained parallelism in a dynamic (assignment at runtime) and in a static (a priori assignment) way. The performance evaluation showed that the static assignment is as efficient as a state-of-the-art barrier. Thereby, parallelism is explicitly expressed in a model and implemented in a timing analyzable way.

There are many high-speed TCP variants with different congestion control algorithms, which are designed for specific settings or use cases. Distinct features of these algorithms are meant to optimize different aspects of network performance, and the choice of TCP variant strongly influences application performance. However, setting up tests to help with the decision of which variant to use can be problematic, as many systems are not designed to deal with high bandwidths, such as 10 Gbps or more. This paper provides an overview of pitfalls and challenges of realistic network analysis to help in the decision making process.

Liver resection is the best treatment for metastatic colorectal cancer (CRC). Hepatic lymph node metastases are considered as extrahepatic disease and represent an unfavorable prognostic factor. However, extrahepatic disease, when resectable, provides no contraindication for surgical therapy. The aim of this study was to evaluate the prevalence of hepatic lymph node involvement in our patients' cohort.Twenty patients submitted to resection for colorectal liver metastases were studied prospectively. Three areas for lymph node dissection were defined and analyzed separately. Lymph nodes were examined by hematoxylin and eosin staining and immunohistochemistry for Pan-Keratin.In average, 5 lymph nodes were harvested per patient. Macroscopic enlargement was not a definite sign for metastatic involvement. No morbidity or mortality was associated with lymphadenectomy. In our patients' collective, no cases of lymph node metastases occurred.There is no evidence of a survival benefit after lymph node dissection in patients with CRC liver metastases in the literature. Systematic lymphadenectomy can, however, provide a prognostic tool to better plan further treatment.

International audience; The EC project parMERASA (Multicore Execution of Parallelized Hard Real-Time Applications Supporting Analyzability) investigated timing-analyzable parallel hard real-time applications running on a predictable multicore processor. A pattern-supported parallelization approach was developed to ease sequential to parallel program transformation based on parallel design patterns that are timing analyzable. The parallelization approach was applied to parallelize the following industrial hard real-time programs: 3D path planning and stereo navigation algorithms (Honeywell International s.r.o.), control algorithm for a dynamic compaction machine (BAUER Maschinen GmbH), and a diesel engine management system (DENSO AUTOMOTIVE Deutschland GmbH). This article focuses on the parallelization approach, experiences during parallelization with the applications, and quantitative results reached by simulation, by static WCET analysis with the OTAWA tool, and by measurement-based WCET analysis with the RapiTime tool.

The logical execution time LET model separates logical from physical execution times. Furthermore, tasks' input and output of data occurs at predictable times that are the tasks' arrival times and deadlines, respectively. The output of data is delayed until the period end meaning that output times have no jitter. The delayed output affects the freshness of data respectively data age between interacting tasks. Recently, critics from control theory arise that the LET approach provides outdated data. We analyze the data age of communicating tasks and propose an approach that reduces the data age. Therefore, we reduce the LET of tasks such that output data is provided earlier than at a task's deadline, but still preserve the predictability of output times. To confirm the improvement on the data age, we simulate 100 randomly generated task sets. Moreover, we also simulate a task set of a real-world automotive benchmark and show an enhancement of the average data age of approximately 33i¾ź% with our approach compared to the LET model.

International audience; The EC FP-7 project parMERASA (Multi-Core Execution of Parallelised Hard Real-Time Applications Supporting Analysability, Oct. 1, 2011 until Sept. 30, 2014) provides a timing analysable system of parallel hard real-time applications running on a scalable multi-core processor. parMERASA goes one step beyond mixed criticality demands: It targets future complex control algorithms by parallelising hard real-time programs to run on predictable multi-/many-core processors. A software engineering approach was developed to ease sequential to parallel program transformation by developing and supporting suitable parallel design patterns that are analysable. The following sequential hard real-time programs were parallelised by applying the pattern-oriented parallelisation approach: 3D path planning and stereo navigation algorithms (Honeywell International s.r.o.), diesel engine management system (DENSO AUTOMOTIVE Deutschland GmbH), and the control algorithm for a dynamic compaction machine (BAUER Maschinen GmbH). The paper reports on parallelisation approach, experiences made during parallelisation with applications, tools and multi-core architecture, scalability of applications and quantitative results reached.