43 research outputs found
Development of a through-process simulation workflow for spiral pipe forming including evolution of texture and dislocation substructure
Spiral forming is a widely used industrial method for the manufacture of large diameter welded pipes from levelled steel strip. However, the multi-step helical forming process
and post-treatment of the pipe influence the material behavior and alter the final mechanical
anisotropy of the product. In addition, the complex microstructures of modern pipeline steels
contain various sources of anisotropy including residual stresses, crystallographic and
morphologic textures, and directional dislocation substructures. They do not only affect the
local and global pipe strength, ductility and toughness during monotonic loading but also cause
strong strain path change effects, e.g. a pronounced Bauschinger effect. Anisotropy thus poses
a true challenge to pipeline designers making it difficult to accurately predict the final pipe
behavior from the known properties of the hot-rolled high-strength coil, the starting point of the
forming process. Still, such predictive power is vital to guarantee the structural integrity of
pipelines without failure in case of in-service loads beyond the elastic range. The pipe
manufacturing process can be simplified into two steps: decoiling (incl. levelling) and spiral
forming. For subsequent quality control, samples are extracted from the pipe, per standard
flattened and tensile tested in hoop direction. With regard to developing a computational twin
of the complete manufacturing and testing process, we represent each step by a separate finite
element (FE) model. The full through-process simulation workflow thus necessitates tools to
transfer the material state between individual FE models. Here, we present such a workflow for
the dislocation substructural hardening model by [Peeters et al., Acta Mater. (2001) 49:1607-
1619]. For each material point, macroscopic and microscopic state variables, including residual
stress, crystallographic texture and dislocation densities, are first interpolated and then
transferred to the next model. In this way, the evolution of different anisotropy sources can be
studied starting from coil via pipe and ending with tensile testin
Production of porous ÎČ-Type Tiâ40Nb alloy for biomedical applications: Comparison of selective laser melting and hot pressing
We used selective laser melting (SLM) and hot pressing of mechanically-alloyed ÎČ-type Tiâ40Nb powder to fabricate macroporous bulk specimens (solid cylinders). The total porosity, compressive strength, and compressive elastic modulus of the SLM-fabricated material were determined as 17% ± 1%, 968 ± 8 MPa, and 33 ± 2 GPa, respectively. The alloyâs elastic modulus is comparable to that of healthy cancellous bone. The comparable results for the hot-pressed material were 3% ± 2%, 1400 ± 19 MPa, and 77 ± 3 GPa. This difference in mechanical properties results from different porosity and phase composition of the two alloys. Both SLM-fabricated and hot-pressed cylinders demonstrated good in vitro biocompatibility. The presented results suggest that the SLM-fabricated alloy may be preferable to the hot-pressed alloy for biomedical applications, such as the manufacture of load-bearing metallic components for total joint replacements
HIV-1 induces telomerase activity in monocyte-derived macrophages, possibly safeguarding one of its reservoirs
Monocyte-derived macrophages (MDM) are widely distributed in all tissues and organs, including the central nervous system, where they represent the main part of HIV-infected cells. In contrast to activated CD4+ T lymphocytes, MDMare resistant to cytopathic effects and survive HIV infection for a long period of time. The molecular mechanisms of how HIV is able to persist in macrophages are not fully elucidated yet. In this context, we have studied the effect of in vitro HIV-1 infection on telomerase activity (TA), telomere length, and DNA damage. Infection resulted in a significant induction of TA. This increase was directly proportional to the efficacy of HIV infection and was found in both nuclear and cytoplasmic extracts, while neither UV lightinactivated HIV nor exogenous addition of the viral protein Tat or gp120 affected TA. Furthermore, TA was not modified during monocyte-macrophage differentiation, MDMactivation, or infection with vaccinia virus. HIV infection did not affect telomere length. However, HIV-infectedMDMshowed less DNA damage after oxidative stress than noninfected MDM, and this resistance was also increased by overexpressing telomerase alone. Taken together, our results suggest that HIV induces TA inMDMand that this induction might contribute to cellular protection against oxidative stress, which could be considered a viral strategy to make macrophages better suited as longer-lived, more resistant viral reservoirs. In the light of the clinical development of telomerase inhibitors as anticancer therapeutics, inhibition of TA in HIV-infected macrophages might also represent a novel therapeutic target against viral reservoirs.Fil: Reynoso, Rita Paola. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Oficina de CoordinaciĂłn Administrativa Houssay. Instituto de Investigaciones BiomĂ©dicas en Retrovirus y Sida. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones BiomĂ©dicas en Retrovirus y Sida; Argentina. University of Natural Resources and Life Sciences Vienna; AustriaFil: Wieser, Matthias. University of Natural Resources and Life Sciences Vienna; AustriaFil: Ojeda, Diego. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Oficina de CoordinaciĂłn Administrativa Houssay. Instituto de Investigaciones BiomĂ©dicas en Retrovirus y Sida. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones BiomĂ©dicas en Retrovirus y Sida; ArgentinaFil: Bönisch, Maximilian. University of Natural Resources and Life Sciences Vienna; AustriaFil: KĂŒhnel, Harald. University of Natural Resources and Life Sciences Vienna; AustriaFil: Bolcic, Federico Martin. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Oficina de CoordinaciĂłn Administrativa Houssay. Instituto de Investigaciones BiomĂ©dicas en Retrovirus y Sida. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones BiomĂ©dicas en Retrovirus y Sida; ArgentinaFil: Quendler, Heribert. University of Natural Resources and Life Sciences Vienna; AustriaFil: Grillari, Johannes. University of Natural Resources and Life Sciences Vienna; AustriaFil: Grillari Voglauer, Regina. University of Natural Resources and Life Sciences Vienna; AustriaFil: Quarleri, Jorge Fabian. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Oficina de CoordinaciĂłn Administrativa Houssay. Instituto de Investigaciones BiomĂ©dicas en Retrovirus y Sida. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones BiomĂ©dicas en Retrovirus y Sida; Argentin
Development of a network of genetic reserves for wild celery in Germany (GE-Sell)
Die Technik des genetischen Erhaltungsgebiets ist ein anwendungsbereites Verfahren zur In-situ-Erhaltung von wildlebenden Verwandten unserer Kulturpflanzen. Bei dem Verfahren wird die dynamische Erhaltung von Populationen, die in ihren natĂŒrlichen LebensrĂ€umen Evolutionsprozessen ausgesetzt sind, mit der statischen Erhaltung pflanzengenetischer Ressourcen in Genbanken kombiniert und somit die nachhaltige Nutzung dieser Arten ermöglicht. Im Modell- und Demonstrationsvorhaben "Genetische Erhaltungsgebiete fĂŒr Wildselleriearten (Apium und Helosciadium) als Bestandteil eines Netzwerks genetischer Erhaltungsgebiete in Deutschland" (GESell) wurden wissenschaftliche und organisatorische Fragestellungen zur Umsetzung dieser Technik bearbeitet. Ziel des Projekts war die modellhafte Einrichtung von 45 genetischen Erhaltungsgebieten (GenEG) fĂŒr Wildselleriearten und der Aufbau eines bundesweiten Netzwerks aus lokalen Akteuren. Zur Identifizierung der GenEG wurde das monografische Verfahren angewendet.
FĂŒr die vier in Deutschland vorkommenden Wildselleriearten wurden zum Projektstart im Jahr 2015 aus 2400 Fundortdaten 322 Standorte fĂŒr PrĂ€senzkontrollen ausgewĂ€hlt. Im Anschluss wurden fĂŒr rund 100 möglichst vitale und ungefĂ€hrdete Vorkommen, die sich ĂŒber verschiedene NaturrĂ€ume und Habitate verteilen, genetische DiversitĂ€tsanalysen durchgefĂŒhrt. Anhand der Kartierungs- und Analyseergebnisse wĂ€hlte das Projektteam zwischen 11 und 15 Vorkommen pro Art aus, die insgesamt die innerartliche Vielfalt der jeweiligen Arten bestmöglich reprĂ€sentieren. FĂŒr diese Vorkommen wurden die Einrichtung und ein langfristiges Management der GenEG in Zusammenarbeit mit lokalen Akteuren angestrebt. Bis zum April 2020 wurden bereits 15 GenEG eingerichtet.The genetic reserve conservation technique is a ready-to-use procedure for in situ conservation of crop wild relatives. The approach combines the dynamic conservation of populations exposed to evolutionary processes in their natural habitats with the static conservation of plant genetic resources in gene banks, thus enabling the sustainable use of these species. In the model and demonstration project "Genetic reserves for wild celery species (Apium and Helosciadium) as part of a network of genetic reserves in Germany" (GE-Sell) scientific and organisational aspects of the implementation of genetic reserves were investigated. The aim of the project was the establishment of 45 genetic reserves for wild celery species and the establishment of a nationwide network of local stakeholders. The monographic approach was used to identify the genetic reserves.
For the four wild celery species occurring in Germany, around 350 occurrences were selected from 2400 known sites for the verification of these occurrences at the project start in 2015. Thereafter, genetic diversity analyses were carried out for approximately 100 occurrences that are as vital as possible, non-endangered and distributed over various ecogeographic regions and habitat types. Based on the survey and analysis results, the project team selected between 11 and 15 occurrences per species, which together represent the intra-species diversity of the respective species best. For these occurrences, the project team aimed at the establishment and long-term management of the genetic reserves in cooperation with local stakeholders. By April 2020, 15 genetic reserves had already been established
Epigenetic dynamics of monocyte-to-macrophage differentiation
Background Monocyte-to-macrophage differentiation involves major biochemical and structural changes. In order to elucidate the role of gene regulatory changes during this process, we used high-throughput sequencing to analyze the complete transcriptome and epigenome of human monocytes that were differentiated in vitro by addition of colony-stimulating factor 1 in serum-free medium. Results Numerous mRNAs and miRNAs were significantly up- or down-regulated. More than 100 discrete DNA regions, most often far away from transcription start sites, were rapidly demethylated by the ten eleven translocation enzymes, became nucleosome-free and gained histone marks indicative of active enhancers. These regions were unique for macrophages and associated with genes involved in the regulation of the actin cytoskeleton, phagocytosis and innate immune response. Conclusions In summary, we have discovered a phagocytic gene network that is repressed by DNA methylation in monocytes and rapidly de-repressed after the onset of macrophage differentiation
Kriterien fĂŒr die Auswahl einer Softwarelösung fĂŒr den Betrieb eines Repositoriums fĂŒr Forschungsdaten
Die öffentliche Bereitstellung von Forschungsdaten zur Nachnutzung im Sinne von Open Science ist Bestandteil des Lebenszyklus von Forschungsdaten und erlangt zunehmende Relevanz. Eine zitierbare Veröffentlichung dieser Daten zeugt von einer transparenten Forschung, belegt die Forschungsleistung eines Forschenden sowie der jeweiligen Einrichtung und macht Forschung reproduzierbar und damit ĂŒberprĂŒfbar. Forschungsförderer erwarten bereits bei der Antragstellung die Dokumentation und Planung eines umsichtigen und nachhaltigen Umgangs mit Forschungsdaten, bspw. in Form eines Datenmanagementplans, der unter anderem Angaben zu geplanten Lizenzen fĂŒr Forschungsdaten, Rechten an Daten etc. enthĂ€lt. Die Umsetzung des Datenmanagementplans ist ein kontinuierlicher Prozess im Laufe eines Projekts und nicht auf eine Datenveröffentlichung zum Projektende hin beschrĂ€nkt. Der Umgang mit Forschungsdaten wird unter anderem in den Richtlinien Guter Wissenschaftlicher Praxis[1], den Open-Access-Policies von Hochschulen, Forschungsinstituten und Forschungsförderern sowie in den âData Policiesâ von Zeitschriften adressiert. Repositorien bilden das technische GrundgerĂŒst fĂŒr das Forschungsdatenmanagement, da sie den gesamten Prozess von der Ăbernahme ĂŒber die QualitĂ€tskontrolle bis hin zur zitierfĂ€higen Veröffentlichung unterstĂŒtzen. Softwarelösungen fĂŒr Repositorien sind fĂŒr unterschiedliche Zwecke und Einsatzszenarien verfĂŒgbar. Zu den verbreitetsten zĂ€hlen beispielsweise Fedora, DSpace, MyCoRe, Islandora, EPrints, Dataverse, Rosetta, Archivematica und Invenio. Die Bestimmung von Kriterien fĂŒr die Auswahl eines Repositoriums ist nicht trivial und es mĂŒssen neben Aspekten der Wirtschaftlichkeit, Skalierbarkeit und FunktionalitĂ€t noch weitere Kriterien wie die Dokumentation, Verbreitung, Entwicklungsperspektive sowie das Daten- und Lizenzmodell berĂŒcksichtigt werden. Der Aufwand fĂŒr die Erarbeitung eines Kriterienkatalogs darf nicht unterschĂ€tzt werden. Im Folgenden bezeichnet Repositorium eine Softwarelösung, die - eingebettet in eine Organisationsstruktur und gegebenenfalls im Kontext weiterer Systeme - Forschungsdaten ĂŒbernimmt, verwaltet und publiziert. Daraus ergeben sich zwangslĂ€ufig AbhĂ€ngigkeiten zur betreibenden organisatorischen Einheit und der grundlegenden technischen Infrastruktur fĂŒr den Betrieb der Software und die Speicherung der Daten. In diesem Artikel werden verschiedene Aspekte prĂ€sentiert, die fĂŒr den Auswahlprozess potentiell relevant sind. [1] Siehe auch Kodex der DFG zur guten wissenschaftlichen Praxis: https://www.dfg.de/foerderung/grundlagen_rahmenbedingungen/gwp
Prenatal exposures and exposomics of asthma
This review examines the causal investigation of preclinical development of childhood asthma using exposomic tools. We examine the current state of knowledge regarding early-life exposure to non-biogenic indoor air pollution and the developmental modulation of the immune system. We examine how metabolomics technologies could aid not only in the biomarker identification of a particular asthma phenotype, but also the mechanisms underlying the immunopathologic process. Within such a framework, we propose alternate components of exposomic investigation of asthma in which, the exposome represents a reiterative investigative process of targeted biomarker identification, validation through computational systems biology and physical sampling of environmental medi
TRY plant trait database â enhanced coverage and open access
Plant traits - the morphological, anatomical, physiological, biochemical and phenological characteristics of plants - determine how plants respond to environmental factors, affect other trophic levels, and influence ecosystem properties and their benefits and detriments to people. Plant trait data thus represent the basis for a vast area of research spanning from evolutionary biology, community and functional ecology, to biodiversity conservation, ecosystem and landscape management, restoration, biogeography and earth system modelling. Since its foundation in 2007, the TRY database of plant traits has grown continuously. It now provides unprecedented data coverage under an open access data policy and is the main plant trait database used by the research community worldwide. Increasingly, the TRY database also supports new frontiers of traitâbased plant research, including the identification of data gaps and the subsequent mobilization or measurement of new data. To support this development, in this article we evaluate the extent of the trait data compiled in TRY and analyse emerging patterns of data coverage and representativeness. Best species coverage is achieved for categorical traits - almost complete coverage for âplant growth formâ. However, most traits relevant for ecology and vegetation modelling are characterized by continuous intraspecific variation and traitâenvironmental relationships. These traits have to be measured on individual plants in their respective environment. Despite unprecedented data coverage, we observe a humbling lack of completeness and representativeness of these continuous traits in many aspects. We, therefore, conclude that reducing data gaps and biases in the TRY database remains a key challenge and requires a coordinated approach to data mobilization and trait measurements. This can only be achieved in collaboration with other initiatives