Search

A design for a 4 m long, ultra-light, high-gain, helical Antenna made from fiber-composite material will be presented. The antenna was designed for the DLR NanoSatellite Mission AISat to receive signals from the Automatic Identification System (AIS) of maritime applications. A description of the antenna deployment strategy including release mechanisms will be given. The proof of concept will be presented based on experimental results gained during the 15. DLR parabolic flight campaign (PFC) in March 2010 and several development tests. Finally, in-orbit demonstration was performed during the two years of operation of the AISat after the successful launch on June 30, 2014 from Sriharikota (India). The AISat satellite was developed at the DLR Institute of Space Systems aiming at the worldwide receiving of AIS signals. These signals can usually be received along coast lines or from ship to ship in range of sight. They provide identity, position, velocity and heading and are therefore used for ship tracking. A number of AIS satellites already exist but especially in areas with high ship traffic density identification problems arose due to the high signal density. Therefore AISat has a distinctive ultra-light, high-gain, helical antenna which allows to focus on comparably small areas on the Earth surface. IT thus shall enable the receiving of Class A and B and SART signals especially in high traffic density zones. The antenna is a 4 m long and 0.57 m in diameter deployable helix antenna made from fiber composite material, which can be stowed in a very flat volume of merely 100 mm height. The wire of the antenna is made from carbon fiber material with a diameter of 8 mm. It is covered with a copper cord for high electrical conductivity. Based on its design with 8 windings the total length of the wire itself is approx. 16 m. Through the dedicated usage of fiber composite materials this wire weighs less than 1 kg including the copper cord. In stowed configuration, in which it is held down by 3 release mechanisms, the antenna has stored elastic energy like in a spiral spring. After release the structure deploys autonomously in orbit to a length of 4 m. When deployed, the antenna is still pre-stressed using control cords in order to increase its bending stiffness.

Summary The exon junction complex (EJC) connects spliced mRNAs to posttranscriptional processes including RNA localization, transport, and regulated degradation. Here, we provide a comprehensive analysis of bona fide EJC binding sites across the transcriptome including all four RNA binding EJC components eIF4A3, BTZ, UPF3B, and RNPS1. Integration of these data sets permits definition of high-confidence EJC deposition sites as well as assessment of whether EJC heterogeneity drives alternative nonsense-mediated mRNA decay pathways. Notably, BTZ (MLN51 or CASC3) emerges as the EJC subunit that is almost exclusively bound to sites 20–24 nucleotides upstream of exon-exon junctions, hence defining EJC positions. By contrast, eIF4A3, UPF3B, and RNPS1 display additional RNA binding sites suggesting accompanying non-EJC functions. Finally, our data show that EJCs are largely distributed across spliced RNAs in an orthodox fashion, with two notable exceptions: an EJC deposition bias in favor of alternatively spliced transcripts and against the mRNAs that encode ribosomal proteins., Graphical Abstract, Highlights • iCLIP analyses of EJC components provide a comprehensive map of bona fide EJCs • EJC proteins, in particular BTZ, are largely restricted to canonical deposition sites • EJCs are enriched on alternatively spliced mRNAs • EJCs are underrepresented on mRNAs encoding ribosomal proteins, Exon junction complexes govern multiple critical decisions in posttranscriptional gene regulation. Using all four RNA binding subunits of the complex, Hauer et al. provide a comprehensive map of bona fide EJCs across a mammalian transcriptome and show enrichment on alternatively spliced mRNAs and underrepresentation on RNAs encoding ribosomal proteins.

Nonsense-mediated mRNA decay (NMD) has originally been described as a surveillance mechanism to inhibit the expression of mRNAs with truncated open reading frames (ORFs) and to contribute to the fidelity of gene expression. It is now recognized that NMD also controls the expression of physiological genes with “intact” mRNA. Stress can decrease NMD efficiency and thus increase the mRNA levels of physiological NMD targets. As stress can also inhibit translation, the net outcome for shaping the proteome is difficult to predict. We have thus analyzed de novo protein synthesis in response to NMD inhibition or the induction of mild endoplasmic reticulum (ER) stress by treatment of cells with the reducing agent dithiotreitol (DTT). For this purpose, we combined pulsed azidohomoalanine (AHA) and stable isotope labeling by amino acids in cell culture (SILAC). Labeled proteins were purified by click chemistry-based covalent coupling to agarose beads, trypsinized, fractionated, and analyzed by mass spectrometry (MS). We find that mild ER stress up-regulates the de novo synthesis of components of all three branches of the unfolded protein response (PERK, IRE1 and ATF6) without increasing eIF2α phosphorylation or impairing of protein translation. In contrast, inhibition of NMD induces de novo protein synthesis of downstream targets of the PERK and IRE1 pathways, whereas we could not detect regulation of ATF6-responsive genes. These data thus support a model that implicates a positive feedback loop of ER stress inhibiting NMD efficiency which further promotes the ER stress response in a branch-specific manner.

International audience; Douze textes de Daniel Charles se trouvent ici ordonnés et présentés par Christine Esclapez etChristian Hauer, musicologues très proches de l’auteur.Tous ont été publiés dans Corps écrit, revue thématique pluridisciplinaire créée par Béatrice Didier en 1982 et dont la publication s’est poursuivie durant neuf ans : trente-six livraisons de haute qualité.Bien difficilement trouvables jusqu’ici, ces écrits mêlant essais, portraits et chroniques composent un quasi-inédit et d’évidence un portrait intellectuel des plus exacts de Daniel Charles. Sa pensée en archipel, familière de la surprise, des enchaînements inattendus, toute d’élégance et d’érudition joueuse s’y donne libre court ; est là en acte, saluant John Cage – dont il reste l’exégète premier – comme le philosophe-artiste Jean Grenier. Mais encore Claude Ballif, compositeur de réflexion et de mémoire qui comme lui a connu la commotion mallarméenne ; mais aussi, en pure vivacité, quelques essentielles notions où silence, improvisation, détachement, ébauche tiennent la meilleure part.Ode au fragment, au non-aligné, au contournement délicat des systèmes, éloge du non finito, ces textes à la rare saveur d’écriture sont, comme l’œuvre entier de Daniel Charles, une grâce offerte à l’esthétique française, que l’auteur du Temps de la voix a si puissamment contribué à redessiner.

Pour répondre à la question « à quel niveau sémiotique la musique communique-t-elle? », nous distinguons trois flux sémiotiques de la narrativité musicale. Le premier flux de narrativité est appelé « substance » : il correspond à la narrativité primaire, présente en toute musique, dans le son même. Le deuxième flux de narrativité est appelé « cadre » : il correspond à la manière dont le temps est organisé – problématisé – dans une oeuvre, un style, une époque. Le troisième flux de narrativité est appelé « intrigue » : il correspond à la mise en intrigue d’une oeuvre. Après avoir précisé en quoi celle-ci consiste, grâce au concept de « tension narrative », nous étudions son actualisation par l’auditeur, et plus précisément l’interaction entre le lecteur et le texte, en insistant sur trois facteurs qui rendent une telle interaction possible : l’intentionnalité, l’embodied simulation et les formes de vitalité., To answer the question “at what semiotic level does mudic communicate?”, we distinguish three semiotic flows of musical narrativity. The first flow of narrativity is called “substance”, and corresponds to primary narrativity present in all music and in sound itself. The second flow of narrativity is called “frame” and corresponds to the way time is organized – problematized – in a musical piece, a style, an era. The third flow of narrativity is called “plot” and corresponds to the emplotment of a work of art. Having clarified the nature of this emplotment by using the concept of “narrative tension”, we then study its actualization by the listener, and more specifically the interaction between reader and text, by insisting on three factors that make it possible : intentionality, embodied simulation and forms of vitality.

Nonsense-mediated RNA decay (NMD) is an RNA-based quality control mechanism that eliminates transcripts bearing premature translation termination codons (PTC). Approximately, one-third of all inherited disorders and some forms of cancer are caused by nonsense or frame shift mutations that introduce PTCs, and NMD can modulate the clinical phenotype of these diseases. 5-azacytidine is an analogue of the naturally occurring pyrimidine nucleoside cytidine, which is approved for the treatment of myelodysplastic syndrome and myeloid leukemia. Here, we reveal that 5-azacytidine inhibits NMD in a dose-dependent fashion specifically upregulating the expression of both PTC-containing mutant and cellular NMD targets. Moreover, this activity of 5-azacytidine depends on the induction of MYC expression, thus providing a link between the effect of this drug and one of the key cellular pathways that are known to affect NMD activity. Furthermore, the effective concentration of 5-azacytidine in cells corresponds to drug levels used in patients, qualifying 5-azacytidine as a candidate drug that could potentially be repurposed for the treatment of Mendelian and acquired genetic diseases that are caused by PTC mutations.

Space antennas with a helical geometry are an advantageous choice for many applications, for instance if the transmission of electromagnetic waves with a circular polarization is intended, or if signals from terrestrial objects shall be received with a high angular resolution. In all these cases the desired electromagnetic properties of a helical geometry can be combined with the mechanical advantage that the antenna acts as a compression spring, provided that its core structure has the necessary high spring stiffness but can nevertheless easily be compressed. Such an antenna has been developed by DLR Institutes in Bremen and Braunschweig together with some industrial partners for a small satellite named AISat which shall be able to pursue the position of individual ships in critical sea areas in order to improve the security of seafare trade. The development was very challenging since the antenna must expand from a stowed stack length of only 10 centimeters to a total length of 4 meters. Only a special carbonfiber core under the conductive coating and a system of stabilizing cords led to a satisfying solution. Both the self-deployment and the self-stabilization function of this innovative antenna concept have been successfully tested and verified under zero-g-conditions in the course of a parabolic flight campaign. It could be convincingly demonstrated that the helical antenna can really achieve its desired contour in weightlessness within some seconds and maintain the required stability. Beyond the current application for the AISat satellite it is therefore a quite promising concept for future satellites.

Para responder a questao “a que nivel semiotico comunica-se a musica ?”, distinguimos tres fluxos semioticos da narratividade musical. O primeiro fluxo de narratividade e chamado de “substância”: ele corresponde a narratividade primaria , presente em todas as musicas, dentro do proprio som . O segundo fluxo de narratividade musical e chamado de “moldura”: ele corresponde a maneira como e organizado o tempo – problematizado – dentro de uma obra, um estilo, uma epoca. O terceiro fluxo de narratividade e chamado de “enredo”: ele corresponde a trama de uma obra. Apos ter precisado em que isso consiste, gracas ao conceito de “tensao narrativa”, nos estudamos sua realizacao pelo ouvinte, e mais precisamente a interacao entre o leitor e o texto , insistindo em tres fatores que tornam tal interacao possivel: a intencionalidade , a embodied simulation e as formas de vitalidade .

Stress adaptation plays a pivotal role in biological processes and requires tight regulation of gene expression. In this study, we explored the effect of cellular stress on mRNA polyadenylation and investigated the implications of regulated polyadenylation site usage on mammalian gene expression. High-confidence polyadenylation site mapping combined with global pre-mRNA and mRNA expression profiling revealed that stress induces an accumulation of genes with differentially expressed polyadenylated mRNA isoforms in human cells. Specifically, stress provokes a global trend in polyadenylation site usage toward decreased utilization of promoter-proximal poly(A) sites in introns or ORFs and increased utilization of promoter-distal polyadenylation sites in intergenic regions. This extensively affects gene expression beyond regulating mRNA abundance by changing mRNA length and by altering the configuration of open reading frames. Our study highlights the impact of post-transcriptional mechanisms on stress-dependent gene regulation and reveals the differential expression of alternatively polyadenylated transcripts as a common stress-induced mechanism in mammalian cells.

Individual-nucleotide resolution crosslinking and immunoprecipitation (iCLIP) allows the determination of crosslinking sites of RNA-binding proteins (RBPs) on RNAs. iCLIP is based on ultraviolet light crosslinking of RBPs to RNA, reverse transcription and high-throughput sequencing of fragments terminating at the site of crosslinking. As a result, start sites of iCLIP fragments are expected to cluster with a narrow distribution, typically representing the site of direct interaction between the RBP and the RNA. Here we show that for several RBPs (eIF4A3, PTB, SRSF3, SRSF4 and hnRNP L), the start sites of iCLIP fragments show a fragment length-dependent broader distribution that can be shifted to positions upstream of the known RNA-binding site. We developed an analysis tool that identifies these shifts and can improve the positioning of RBP binding sites., Individual-nucleotide resolution crosslinking and immunoprecipitation (iCLIP) can map RNA binding sites of RNA-binding proteins (RBPs). Here, the authors report an analysis tool that improves the binding site assignment for some RBPs that have length-dependent broader distribution for their iCLIP fragments.

Therapy of diseases of the central nervous system is a major challenge since drugs have to overcome the blood-brain barrier (BBB). A powerful strategy to enhance cerebral drug concentration is administration of drug-loaded poly(n-butylcyano-acrylate) (PBCA) nanoparticles coated with polysorbate 80 (PS80). This study evaluates the toxicity of PBCA-nanoparticles at the BBB, representing the target organ, the inflammatory response in human whole blood, as the site of administration and in a rat model in vivo. PBCA-nanoparticles were prepared by a mini-emulsion method and characterized concerning size, surface charge, shape and PS80-adsorption. The influence on metabolic activity, cell viability and integrity of the BBB was analyzed in an in vitro model of the BBB. In ex vivo experiments in human whole blood the release of 12 inflammatory cytokines was investigated. In addition, the inflammatory response was studied in vivo in rats and complemented with the analysis of different organ toxicity parameters. PBCA-nanoparticles showed time- and concentration-dependent effects on metabolic activity, cell viability and BBB integrity. No cell death or loss of metabolic activity was observed for nanoparticle-concentrations ≤500μg/ml up to 3h of treatment. Within 12 tested inflammatory cytokines, only interleukin-8 displayed a significant release after nanoparticle exposure in human blood. No severe inflammatory processes or organ damages were identified in rats in vivo. Thus, PBCA-nanoparticles are a promising drug delivery system to overcome the BBB since they showed hardly any cytotoxic or inflammatory effect at therapeutic concentrations and incubation times.

When we hear high-pitched sounds, we tend to imagine objects/events that are visually high and sharp. Conversely, when we hear low-pitched sounds, we tend to imagine objects/events that are visually low and rounded. These kinds of intuitive associations linking stimuli perceived by different senses are called "crossmodal correspondences". The goal of this master’s thesis is to contribute to a synthesis of the knowledge on the links between music and crossmodal correspondences. More precisely, we ask ourselves: what are the crossmodal correspondences that can be used in music, and what are the ins and outs of their musical use? The first part of this thesis is an introduction to crossmodal correspondences. The second part attempts to establish a certain number of crossmodal correspondences involving the sense of hearing. Finally, the last part deals with different problems related to the use of crossmodal correspondences in music.; Lorsque nous entendons des sons aigus, nous avons tendance à imaginer des objets/évènements visuellement hauts et pointus. À l’inverse, lorsque nous entendons des sons graves, nous avons tendance à imaginer des objets/évènements visuellement bas et arrondis. Ce genre d’associations intuitives reliant des stimuli perçus par des sens différents sont appelées « correspondances transmodales ». Le but de ce mémoire est de contribuer à une synthèse des connaissances sur les liens entre la musique et les correspondances transmodales. Plus précisément, nous nous demandons : quelles sont les correspondances transmodales utilisables en musique, et quels sont les tenants et les aboutissants de leur utilisation musicale ? La première partie de ce mémoire est une introduction aux correspondances transmodales. La deuxième partie tente d’établir un certain nombre de correspondances transmodales impliquant le sens de l’ouïe. Enfin, la dernière partie aborde différents problèmes relatifs à l’utilisation des correspondances transmodales en musique.

This research paper proposes a critical approach to learning a musical instrument in people with dyspraxia. It discusses various questions such as decryption and memorization of score, the teacher’s role, the need or not for adequate education material or even the omnipresence of imitation learning in the teaching of instrumental practices. Furthermore, this research highlights the significant differences that exist between persons with developmental coordination disorder (DCD) and people with typical brain development during learning a piece of music.; Le présent mémoire propose une approche critique de l’apprentissage d’un instrument de musique chez des personnes dyspraxiques. Il aborde différentes problématiques comme le déchiffrage et la mémorisation de partition, le rôle de l’enseignant, la nécessité ou non de supports pédagogiques adaptés ou encore l’omniprésence des apprentissages par imitation dans la transmission des pratiques instrumentales. Par ailleurs, ce travail de recherche souligne les différences significatives qui existent entre les personnes atteintes d’un trouble développemental des coordinations (TDC) et les individus à développement « typique » lors de l’apprentissage d’une pièce musicale.

This research paper proposes a critical approach to learning a musical instrument in people with dyspraxia. It discusses various questions such as decryption and memorization of score, the teacher’s role, the need or not for adequate education material or even the omnipresence of imitation learning in the teaching of instrumental practices. Furthermore, this research highlights the significant differences that exist between persons with developmental coordination disorder (DCD) and people with typical brain development during learning a piece of music.; Le présent mémoire propose une approche critique de l’apprentissage d’un instrument de musique chez des personnes dyspraxiques. Il aborde différentes problématiques comme le déchiffrage et la mémorisation de partition, le rôle de l’enseignant, la nécessité ou non de supports pédagogiques adaptés ou encore l’omniprésence des apprentissages par imitation dans la transmission des pratiques instrumentales. Par ailleurs, ce travail de recherche souligne les différences significatives qui existent entre les personnes atteintes d’un trouble développemental des coordinations (TDC) et les individus à développement « typique » lors de l’apprentissage d’une pièce musicale.