221 research outputs found
Contact Temperature Measurements on Hybrid Aluminum–Steel Workpieces in a Cross-Wedge Rolling Process
The Collaborative Research Center 1153 is investigating a novel process chain for manufacturing high-performance hybrid components. The combination of aluminum and steel can reduce the weight of components and lead to lower fuel consumption. During the welding of aluminum and steel, a brittle intermetallic phase is formed that reduces the service life of the component. After welding, the workpiece is heated inhomogeneously and hot-formed in a cross-wedge rolling process. Since the intermetallic phase grows depending on the temperature during hot forming, temperature control is of great importance. In this paper, the possibility of process-integrated contact temperature measurement with thin-film sensors is investigated. For this purpose, the initial temperature distribution after induction heating of the workpiece is determined. Subsequently, cross-wedge rolling is carried out, and the data of the thin-film sensors are compared to the temperature measurements after heating. It is shown that thin-film sensors inserted into the tool are capable of measuring surface temperatures even at a contact time of 0.041 s. The new process monitoring of the temperature makes it possible to develop a better understanding of the process as well as to further optimize the temperature distribution. In the long term, knowledge of the temperatures in the different materials also makes it possible to derive quality characteristics as well as insights into the causes of possible process errors (e.g., fracture of the joining zone)
Potential of process information transfer along the process chain of hybrid components for process monitoring of the cutting process
The production of hybrid components involves a long process chain, which leads to high investment costs even before machining. To increase process safety and process quality during finishing, it is necessary to provide information about the semi-finished parts geometry for the machining process and to identify defect components at an early stage. This paper presents an investigation to predict variations in dimension and cavities inside the material during cross-wedge rolling of shafts based on measured tool pressure. First, the process is investigated with respect to the variation in diameter for three roll gaps and two materials. Subsequently, features are generated from the hydraulic pressures of the tools and multi-linear regression models are developed in order to determine the resulting diameters of the shaft shoulder. These models show better prediction accuracy than models based on meta-data about set roll gap and formed material. The features are additionally used to successfully monitor the process with regard to the Mannesmann effect. Finally, a sensor concept for a new cross-wedge rolling machine to improve the prediction of the workpiece geometry and a new approach for monitoring machining processes of workpieces with dimensional variations are presented for upcoming studies
Fast forward genetics to identify mutations causing a high light tolerant phenotype in Chlamydomonas reinhardtii by whole-genome-sequencing
Schierenbeck L, Ries D, Rogge K, Grewe S, Weisshaar B, Kruse O. Fast forward genetics to identify mutations causing a high light tolerant phenotype in Chlamydomonas reinhardtii by whole-genome-sequencing. BMC Genomics. 2015;16(1): 57.Background:
High light tolerance of microalgae is a desired phenotype for efficient cultivation in large scale production systems under fluctuating outdoor conditions. Outdoor cultivation requires the use of either wild-type or non-GMO derived mutant strains due to safety concerns. The identification and molecular characterization of such mutants derived from untagged forward genetics approaches was limited previously by the tedious and time-consuming methods involving techniques such as classical meiotic mapping. The combination of mapping with next generation sequencing technologies offers alternative strategies to identify genes involved in high light adaptation in untagged mutants.
Results:
We used the model alga Chlamydomonas reinhardtii in a non-GMO mutation strategy without any preceding crossing step or pooled progeny to identify genes involved in the regulatory processes of high light adaptation. To generate high light tolerant mutants, wildtype cells were mutagenized only to a low extent, followed by a stringent selection. We performed whole-genome sequencing of two independent mutants hit1 and hit2 and the parental wildtype. The availability of a reference genome sequence and the removal of shared bakground variants between the wildtype strain and each mutant, enabled us to identify two single nucleotide polymorphisms within the same gene Cre02.g085050, hereafter called LRS1 (putative Light Response Signaling protein 1). These two independent single amino acid exchanges are both located in the putative WD40 propeller domain of the corresponding protein LRS1. Both mutants exhibited an increased rate of non-photochemical-quenching (NPQ) and an improved resistance against chemically induced reactive oxygen species. In silico analyses revealed homology of LRS1 to the photoregulatory protein COP1 in plants.
Conclusions:
In this work we identified the nuclear encoded gene LRS1 as an essential factor for high light adaptation in C. reinhardtii. The causative random mutation within this gene was identified by a rapid and efficient method, avoiding any preceding crossing step, meiotic mapping, or pooled progeny. Our results open up new insights into mechanisms of high light adaptation in microalgae and at the same time provide a simplified strategy for non-GMO forward genetics, a crucial precondition that could result in the identification of key factors for economically relevant biological processes within algae
Investigation of the prediction accuracy of a finite element analysis model for the coating thickness in cross-wedge rolled coaxial hybrid parts
The Collaborative Research Centre 1153 (CRC 1153) "Process chain for the production of hybrid high-performance components through tailored forming" aims to develop new process chains for the production of hybrid bulk components using joined semi-finished workpieces. The subproject B1 investigates the formability of hybrid parts using cross-wedge rolling. This study investigates the reduction of the coating thickness of coaxially arranged semi-finished hybrid parts through cross-wedge rolling. The investigated parts are made of two steels (1.0460 and 1.4718) via laser cladding with hot-wire. The rolling process is designed by finite element (FE)-simulations and later experimentally investigated. Research priorities include investigations of the difference in the coating thickness of the laser cladded 1.4718 before and after cross-wedge rolling depending on the wedge angle β, cross-section reduction DA, and the forming speed v. Also, the simulations and the experimental trials are compared to verify the possibility of predicting the thickness via finite element analysis (FEA). The main finding was the ability to describe the forming behavior of coaxially arranged hybrid parts at a cross-section reduction of 20% using FEA. For a cross-section reduction of 70% the results showed a larger deviation between simulation and experimental trials. The deviations were between 0.8% and 26.2%. © 2019 by the authors
Point-of-care lung ultrasound in COVID-19 patients: inter- and intra-observer agreement in a prospective observational study
With an urgent need for bedside imaging of coronavirus disease 2019 (COVID-19), this study's main goal was to assess inter- and intraobserver agreement in lung ultrasound (LUS) of COVID-19 patients. In this single-center study we prospectively acquired and evaluated 100 recorded ten-second cine-loops in confirmed COVID-19 intensive care unit (ICU) patients. All loops were rated by ten observers with different subspeciality backgrounds for four times by each observer (400 loops overall) in a random sequence using a web-based rating tool. We analyzed inter- and intraobserver variability for specific pathologies and a semiquantitative LUS score. Interobserver agreement for both, identification of specific pathologies and assignment of LUS scores was fair to moderate (e.g., LUS score 1 Fleiss' kappa =0.27; subpleural consolidations Fleiss' kappa =0.59). Intraobserver agreement was mostly moderate to substantial with generally higher agreement for more distinct findings (e.g., lowest LUS score 0 vs. highest LUS score 3 (median Fleiss' kappa =0.71 vs. 0.79) or air bronchograms (median Fleiss' kappa =0.72)). Intraobserver consistency was relatively low for intermediate LUS scores (e.g. LUS Score 1 median Fleiss' kappa =0.52). We therefore conclude that more distinct LUS findings (e.g., air bronchograms, subpleural consolidations) may be more suitable for disease monitoring, especially with more than one investigator and that training material used for LUS in point-of-care ultrasound (POCUS) should pay refined attention to areas such as B-line quantification and differentiation of intermediate LUS scores
Primary ChAdOx1 vaccination does not reactivate pre-existing, cross-reactive immunity
Currently available COVID-19 vaccines include inactivated virus, live attenuated virus, mRNA-based, viral vectored and adjuvanted protein-subunit-based vaccines. All of them contain the spike glycoprotein as the main immunogen and result in reduced disease severity upon SARS-CoV-2 infection. While we and others have shown that mRNA-based vaccination reactivates pre-existing, cross-reactive immunity, the effect of vector vaccines in this regard is unknown. Here, we studied cellular and humoral responses in heterologous adenovirus-vector-based ChAdOx1 nCOV-19 (AZ; Vaxzeria, AstraZeneca) and mRNA-based BNT162b2 (BNT; Comirnaty, BioNTech/Pfizer) vaccination and compared it to a homologous BNT vaccination regimen. AZ primary vaccination did not lead to measurable reactivation of cross-reactive cellular and humoral immunity compared to BNT primary vaccination. Moreover, humoral immunity induced by primary vaccination with AZ displayed differences in linear spike peptide epitope coverage and a lack of anti-S2 IgG antibodies. Contrary to primary AZ vaccination, secondary vaccination with BNT reactivated pre-existing, cross-reactive immunity, comparable to homologous primary and secondary mRNA vaccination. While induced anti-S1 IgG antibody titers were higher after heterologous vaccination, induced CD4(+) T cell responses were highest in homologous vaccinated. However, the overall TCR repertoire breadth was comparable between heterologous AZ-BNT-vaccinated and homologous BNT-BNT-vaccinated individuals, matching TCR repertoire breadths after SARS-CoV-2 infection, too. The reasons why AZ and BNT primary vaccination elicits different immune response patterns to essentially the same antigen, and the associated benefits and risks, need further investigation to inform vaccine and vaccination schedule development
Нейроендокринний супровід поліваріантних ефектів біоактивної води Нафтуся на рівень хронічного стресу у жінок з різним оваріальним статусом
Проанализированы изменения нейроэндокринных показателен, сопутствующие поливариантным эффектам биоактивной воды Нафтуся курорта Трускавец на уровень хронического стресса у женщин детородного возраста с различным овариальным статусом. Обнаружена значительная (R=0,59) каноническая корреляционная связь между динамикой нейро-гормонального индекса стресса, с одной стороны, и вегетативной реактивности, лютеинизирующего гормона, тиреотропного гормона, тироксина и прогестерона - с другой стороны.The changes in neuroendocrine parameters, concomitant multivariate effects of bioactive water Naftussya spa Truskavets to the level of chronic stress in women of childbearing age with different ovarian status. A significant (R=0,59) canonical correlation between the dynamics of the neuro-hormonal index of stress, on the one hand, and autonomic reactivity, luteinizing hormone, thyroid-stimulating hormone, thyroxine and progesterone - the other side
Profiling of WDR36 Missense Variants in German Patients with Glaucoma
PURPOSE. Mutations in WDR36 were recently reported in patients with adult-onset primary open-angle glaucoma (POAG). In this study, the prevalence of WDR36 variants was investigated in patients with glaucoma who were of German descent with diverse age of onset and intraocular pressure levels. METHODS. Recruited were 399 unrelated patients with glaucoma and 376 healthy subjects of comparable age and origin, who had had repeated normal findings in ophthalmic examinations. The frequency of observed variants was obtained by direct sequencing of the entire WDR36 coding region. RESULTS. A total of 44 WDR36 allelic variants were detected, including 14 nonsynonymous amino acid alterations, of which 7 are novel (P31T, Y97C, D126N, T403A, H411Y, H411L, and P487R) and 7 have been reported (L25P, D33E, A163V, H212P, A449T, D658G and I264V). Of these 14 variants, 6 were classified as polymorphisms as they were detected in patients and control individuals at similar frequencies. Eight variants present in 15 patients (3.7%) but only 1 control individual (0.2%) were defined as putative disease-causing variants (P 0.0005). Within this patient group, 12 (80%) presented with high and 3 (20%) with low intraocular pressure. Disease severity and age of onset showed a broad range. CONCLUSIONS. The occurrence of several rare putative diseasecausing variants in patients with glaucoma suggests that WDR36 may be a minor disease-causing gene in glaucoma, at least in the German population. The large variability in WDR36, though, requires functional validation of these variants, once its function is characterized.UCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias Básicas::Centro de Investigación en Biología Celular y Molecular (CIBCM)UCR::Vicerrectoría de Docencia::Ciencias Básicas::Facultad de Ciencias::Escuela de Biologí
Inducing behavioural change in society through communication and education in sustainable manufacturing
The United Nations considers the mobilization of the broad public to be the essential requirement for achieving a shift towards a more sustainable development. Science can play a vital role in Education for Sustainable Development (ESD) by contributing to ESD-related research and development on the one hand, and by becoming active awareness raisers themselves in education and multiplier networks. Specifically, the use of special Learnstruments, and investment inOpen Educationformats among other educational tools, may pave the way for accelerated apprehension and appreciation of sustainable manufacturing topics among the greater populace
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