@inproceedings{KaloumenosAmrheinGlaabetal.2010, author = {Kaloumenos, Mareiki and Amrhein, Frank and Glaab, Johannes and Sauer, Michael and Hellmann, Ralf and Kaloudis, Michael}, title = {Development of a UV-Light Source with Highest Power Density Based on Light Emitting Diode Technology for Applications in Production Engineering, in Production Engineering and manufacturing Systems}, series = {Proceedings of the XXIV International Scientific Conference Miskolc, Ungarn}, booktitle = {Proceedings of the XXIV International Scientific Conference Miskolc, Ungarn}, year = {2010}, subject = {Lumineszenzdiode}, language = {en} } @article{BochtlerHellmannKaloudisetal.2010, author = {Bochtler, Ulrich and Hellmann, Ralf and Kaloudis, Michael and Amrhein, Frank and Glaab, Johannes and Kaloumenos, Mareiki and Sauer, Michael and Gockel, Tilo}, title = {LUVLED - UV-Leistungslichtquelle auf Leuchtdiodenbasis}, series = {Elektor Sonderheft, LEDs 2}, volume = {2011}, journal = {Elektor Sonderheft, LEDs 2}, number = {2}, publisher = {Elektor-Verlag}, address = {Aachen}, pages = {57 -- 63}, year = {2010}, subject = {Lumineszenzdiode}, language = {de} } @inproceedings{SauerKeferRuppertetal.2019, author = {Sauer, Theresia and Kefer, Stefan and Ruppert, Wolfgang and Hellmann, Ralf and Kaloudis, Michael}, title = {Integration of Bragg grating sensors in components made of carbon fiber reinforced polymers}, series = {Tagungsband der 20. GMA/ITG-Fachtagung Sensoren und Messsysteme 2019, 25.06.2019 - 26.06.2019, N{\"u}rnberg, Deutschland}, booktitle = {Tagungsband der 20. GMA/ITG-Fachtagung Sensoren und Messsysteme 2019, 25.06.2019 - 26.06.2019, N{\"u}rnberg, Deutschland}, isbn = {978-3-9819376-0-2}, doi = {10.5162/sensoren2019/P3.12}, pages = {806 -- 810}, year = {2019}, abstract = {This contribution discusses the integration of polymer planar Bragg grating sensors (PPBG) into carbon fiber reinforced polymer (CFRP) components. For the first time, it is shown that PPBGs based on cyclic olefin copolymers can be integrated into commercial-grade composites, thereby withstanding the demanding production processes. Pre-impregnated fibers are stacked and partially modified to form a sensor pocket. Afterwards, the CFRP specimen containing the optical sensor is cured in a heated mechanical press for 2 hours at a pressure of 7 bar and a temperature of 120 °C. A subsequent evalutaion of the sensor signal shows a Bragg wavelength shift of 1236 pm and a decline in signal amplitude of -2 dB. Three-point flexural tests of the cured sample reveal a linear behavior of the sensor signal towards external loads. The determined sensitivity in dependence of the CFRP specimen's maximum central deflection is -112 pm/mm, while correlation to the applied force results in a sensitivity of -5 pm/N.}, subject = {Bragg-Reflektor}, language = {en} } @article{KeferSauerHessleretal.2020, author = {Kefer, Stefan and Sauer, Theresia and Hessler, Steffen and Kaloudis, Michael and Hellmann, Ralf}, title = {Microstructure-Based Fiber-to-Chip Coupling of Polymer Planar Bragg Gratings for Harsh Environment Applications}, series = {Sensors (Basel)}, volume = {20}, journal = {Sensors (Basel)}, number = {19}, doi = {10.3390/s20195452}, pages = {5452 -- 5452}, year = {2020}, abstract = {This article proposes and demonstrates a robust microstructure-based fiber-to-chip coupling scheme for planar Bragg grating devices. A polymer planar Bragg grating substrate is manufactured and microstructured by means of a micromilling process, while the respective photonic structures are generated by employing a sophisticated single-writing UV-exposure method. A stripped standard single mode fiber is inserted into the microstructure, which is filled with a UV-curable adhesive, and aligned with the integrated waveguide. After curing, final sensor assembly and thermal treatment, the proposed coupling scheme is capable of withstanding pressures up to 10 bar, at room temperature, and pressures up to 7.5 bar at an elevated temperature of 120 °C. Additionally, the coupling scheme is exceedingly robust towards tensile forces, limited only by the tensile strength of the employed single mode fiber. Due to its outstanding robustness, the coupling scheme enables the application of planar Bragg grating devices in harsh environments. This fact is underlined by integrating a microstructure-coupled photonic device into the center of a commercial-grade carbon fiber-reinforced polymer specimen. After its integration, the polymer-based Bragg grating sensor still exhibits a reflection peak with a dynamic range of 24 dB, and can thus be employed for sensing purposes.}, language = {en} } @article{SieversSauerHausmannetal.2021, author = {Sievers, Aaron and Sauer, Liane and Hausmann, Michael and Hildenbrand, Georg}, title = {Eukaryotic Genomes Show Strong Evolutionary Conservation of k-mer Composition and Correlation Contributions between Introns and Intergenic Regions}, series = {Genes}, volume = {12}, journal = {Genes}, number = {10}, publisher = {MDPI AG}, issn = {2073-4425}, doi = {https://doi.org/10.3390/genes12101571}, year = {2021}, abstract = {Several strongly conserved DNA sequence patterns in and between introns and intergenic regions (IIRs) consisting of short tandem repeats (STRs) with repeat lengths \<3 bp have already been described in the kingdom of Animalia. In this work, we expanded the search and analysis of conserved DNA sequence patterns to a wider range of eukaryotic genomes. Our aims were to confirm the conservation of these patterns, to support the hypothesis on their functional constraints and/or the identification of unknown patterns. We pairwise compared genomic DNA sequences of genes, exons, CDS, introns and intergenic regions of 34 Embryophyta (land plants), 30 Protista and 29 Fungi using established k-mer-based (alignment-free) comparison methods. Additionally, the results were compared with values derived for Animalia in former studies. We confirmed strong correlations between the sequence structures of IIRs spanning over the entire domain of Eukaryotes. We found that the high correlations within introns, intergenic regions and between the two are a result of conserved abundancies of STRs with repeat units ≤2 bp (e.g., (AT)n). For some sequence patterns and their inverse complementary sequences, we found a violation of equal distribution on complementary DNA strands in a subset of genomes. Looking at mismatches within the identified STR patterns, we found specific preferences for certain nucleotides stable over all four phylogenetic kingdoms. We conclude that all of these conserved patterns between IIRs indicate a shared function of these sequence structures related to STRs.}, subject = {Genom}, language = {en} } @article{SieversSauerBischetal.2023, author = {Sievers, Aaron and Sauer, Liane and Bisch, Marc and Sprengel, Jan and Hausmann, Michael and Hildenbrand, Georg}, title = {Moderation of Structural DNA Properties by Coupled Dinucleotide Contents in Eukaryotes}, series = {Genes}, volume = {14}, journal = {Genes}, number = {3}, publisher = {MDPI AG}, issn = {2073-4425}, doi = {https://doi.org/10.3390/genes14030755}, year = {2023}, abstract = {Dinucleotides are known as determinants for various structural and physiochemical properties of DNA and for binding affinities of proteins to DNA. These properties (e.g., stiffness) and bound proteins (e.g., transcription factors) are known to influence important biological functions, such as transcription regulation and 3D chromatin organization. Accordingly, the question arises of how the considerable variations in dinucleotide contents of eukaryotic chromosomes could still provide consistent DNA properties resulting in similar functions and 3D conformations. In this work, we investigate the hypothesis that coupled dinucleotide contents influence DNA properties in opposite directions to moderate each other's influences. Analyzing all 2478 chromosomes of 155 eukaryotic species, considering bias from coding sequences and enhancers, we found sets of correlated and anti-correlated dinucleotide contents. Using computational models, we estimated changes of DNA properties resulting from this coupling. We found that especially pure A/T dinucleotides (AA, TT, AT, TA), known to influence histone positioning and AC/GT contents, are relevant moderators and that, e.g., the Roll property, which is known to influence histone affinity of DNA, is preferably moderated. We conclude that dinucleotide contents might indirectly influence transcription and chromatin 3D conformation, via regulation of histone occupancy and/or other mechanisms.}, subject = {Genom}, language = {en} } @article{KeferSauerHessleretal.2020, author = {Kefer, Stefan and Sauer, Theresia and Hessler, Steffen and Kaloudis, Michael and Schmauss, Bernhard and Hellmann, Ralf}, title = {Robust Polymer Planar Bragg Grating Sensors Embedded in Commercial-Grade Composites}, series = {Polymers}, volume = {12}, journal = {Polymers}, number = {3}, doi = {10.3390/polym12030715}, pages = {715 -- 715}, year = {2020}, abstract = {This contribution demonstrates the functionality of polymer planar Bragg grating (PPBG) sensors integrated into commercial-grade carbon fiber reinforced polymer (CFRP) components. Multiple CFRP specimens are generated by curing a stack of pre-impregnated fibers inside of a heated mechanical press, exposing the polymer sensor to a pressure of 7 bar and a temperature of 120 °C for 2 h. After integration, the sensor still exhibits a strong and evaluable signal. Subsequent flexural experiments reveal a linear response of the integrated sensor's Bragg wavelength to the CFRP specimen's maximum deflection. Additional findings demonstrate that the embedded PPBG can be used to detect plastic deformations of a CFRP workpiece, whereas a linear correlation of plastic deformation to the resulting Bragg signal offset is determined. A plausibility check of the obtained results is delivered by a comparison of three-point flexural experiments on bulk CFRP workpieces, without integrated sensors and additional specimens featuring external optical sensors affixed to their surface. It is found that PPBGs based on cyclic olefin copolymers are able to overcome the temperature-related limitations of traditional polymer-based optical sensors and can thus be directly integrated into commercial-grade composites during production.}, subject = {Bragg-Reflektor}, language = {en} }