TY - JOUR A1 - Dreyer, Christian A1 - Motoc, Dana Luca A1 - Koehler, Mathias A1 - Goldenberg, Leonid T1 - UV LED Curable Perfluoropolyether (PFPE)-Urethane Methacrylate Transparent Coatings for Photonic Applications: Synthesis and Characterization JF - Polymers N2 - The contribution aims to bring forth a novel synthesis route in developing transparent UV LED-curable coatings accounting for various exposure options. A selection of perfluoropolyether (PFPE)-urethane methacrylate and acrylate resins, free-radical photo-initiator Omnirad 2100, and two distinct silane-based crosslinking agents were blended under a weight ratio of 75:20:5 (without crosslinker) and 70:15:5:10, respectively. The coatings were cured under a UV LED 4 × 3 matrix light emitting source, in a chamber under a controlled atmosphere, by means of an in-house developed conveyor belt type platform, at different conveyor belt speeds (5, 50, 150, 250, and 500 mm/s). The morphologies of fabricated coatings were characterized by FTIR revealing high conversion rates (e.g., from 98 to 100%) for increased exposure time as a result of the 5 or 50 mm/s values, on all combinations. Dynamic–mechanical and optical properties of UV LED-cured transparent coatings were also investigated. A negative shift of the glass transition temperature values with a decrease in exposure time, in all combinations, from about 60 °C to 30 °C, along with storage moduli lowering in the glassy plateau further favors higher exposure times for curing. The refractive indices of poly-mers were from 1.38 to 1.40, whereas the thermo-optic coefficients are showing minor changes around the value of 2.55∙10−4 K−1. KW - perfluoropolyether (PFPE) KW - fluoroacrylate KW - UV LED curable coating KW - viscoelastic property KW - refractive index KW - thermo-optic coefficient KW - optical loss KW - dielectric property Y1 - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:526-opus4-19139 VL - 15 IS - 14 PB - MDPI ER - TY - JOUR A1 - Fünning, Tabea A1 - Paul, Martin A1 - Manganelli, Costanza Lucia A1 - Wenger, Christian A1 - Mai, Andreas A1 - Steglich, Patrick T1 - Comparative simulation analysis of photonic ultrasound sensors based on silicon waveguides JF - Scientific Reports N2 - Pressure sensors based on photonic integrated circuits (PIC) offer the prospect of outstanding sensitivities, extreme miniaturization and have the potential for highly scalable production using CMOS compatible processing. PIC-based pressure sensors detect the change in optical properties, i.e. the intensity or phase of the optical carrier wave inside miniaturized waveguide structures. The detection of ultrasound is achieved by engineering the waveguide architecture such that a pressure causes a high change in the effective refractive index of the waveguide. A range of PIC-based pressure sensors have been reported, but a comparison of the sensitivity of the different approaches is not straightforward, since different pressure sensitive waveguide architectures as well as photonic layouts and measurement setups impact the performance. Additionally, the used sensitivity unit is not uniform throughout the different studies, further complicating a comparison. In this work, a detailed simulation study is carried out by finite element modeling of different pressure sensitive waveguide architectures for a consistent comparison. We analyze three different sensor architectures: (A) a free standing membrane located within a tiny air gap above the waveguide, (B) a waveguide located on top of a deflectable membrane as well as (C) a waveguide embedded inside a pressure-sensitive polymer cladding. The mechanical response of the structures and the resulting changes in mode propagation, i.e. the change of the effective refractive index, are analyzed. The waveguide sensitivities in RIU/MPa for different waveguide types (strip, slot) and polarization states (TE, TM) are compared. The results reveal inherent limitations of the different waveguide designs and create a basis for the selection of suitable designs for further ultrasound sensor development. Possibilities for enhancing waveguide sensitivity are identified and discussed. Additionally, we have shown that the studied approaches are extensible to SiN waveguides. Y1 - 2025 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:526-opus4-20560 VL - 15 PB - Springer Nature ER - TY - JOUR A1 - Seeliger, Frank T1 - Betriebliche Einstiegsqualifizierung als zweite Chance JF - BuB : Forum für Bibliothek und Information N2 - Die Ausbildung zum Fachangestellten für Medien und Informationsdienste (FaMI) in der Fachrichtung Bibliothek ist sehr anspruchsvoll und verlangt einiges von den Jugendlichen ab. Daher gilt in der Wildauer Hochschulbibliothek für Lehrlinge der gleiche Grundsatz wie für Studierende: Scheitern ist erlaubt – was sich in der bislang zehnjährigen Erfahrung als Ausbildungsbetrieb allerdings nur einmal bewahrheitet hat. Y1 - 2013 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:526-opus4-9608 UR - http://www.b-u-b.de/pdfarchiv/Heft-BuB_03_2013.pdf SN - 0340-0301 VL - 65 IS - 3 SP - 182 EP - 183 ER - TY - JOUR A1 - Grytsenko, Kostyantyn A1 - Schrader, Sigurd A1 - Detert, Heiner T1 - Ultra-stable dye-filled polytetrafluoroethylene thin films JF - Nanoscience & Technology: Open Access N2 - Polytetrafluoroethylene (PTFE) and polyparaphenylene sulphide (PPS) thin films filled with molecules of different dyes were obtained by co-deposition in vacuum. The PTFE matrix prevented aggregation of dye molecules more strongly, than PPS matrix. During heating PTFE matrix kept the dye molecules in not aggregated state up to dye decomposition temperature. Dyes of all types, buried in the PTFE matrix, exhibited high stability toward actions of external factors: light, temperature, acids. KW - dye KW - PTF KW - PPS KW - nanocomposite KW - thin film KW - optical spectra KW - stability Y1 - 2014 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:526-opus4-5947 SN - 2374-8141 VL - 1 IS - 2 ER - TY - JOUR A1 - Radke, Lars A1 - Sandig, Grit A1 - Lubitz, Annika A1 - Schließer, Ulrike A1 - von Horsten, Hans Henning A1 - Blanchard, Véronique A1 - Keil, Karolin A1 - Sandig, Volker A1 - Giese, Christoph A1 - Hummel, Michael A1 - Hinderlich, Stephan A1 - Frohme, Marcus T1 - In Vitro Evaluation of Glycoengineered RSV-F in the Human Artificial Lymph Node Reactor JF - Bioengineering N2 - Subunit vaccines often require adjuvants to elicit sustained immune activity. Here, a method is described to evaluate the efficacy of single vaccine candidates in the preclinical stage based on cytokine and gene expression analysis. As a model, the recombinant human respiratory syncytial virus (RSV) fusion protein (RSV-F) was produced in CHO cells. For comparison, wild-type and glycoengineered, afucosylated RSV-F were established. Both glycoprotein vaccines were tested in a commercial Human Artificial Lymph Node in vitro model (HuALN®). The analysis of six key cytokines in cell culture supernatants showed well-balanced immune responses for the afucosylated RSV-F, while immune response of wild-type RSV-F was more Th1 accentuated. In particular, stronger and specific secretion of interleukin-4 after each round of re-stimulation underlined higher potency and efficacy of the afucosylated vaccine candidate. Comprehensive gene expression analysis by nCounter gene expression assay confirmed the stronger onset of the immunologic reaction in stimulation experiments with the afucosylated vaccine in comparison to wild-type RSV-F and particularly revealed prominent activation of Th17 related genes, innate immunity, and comprehensive activation of humoral immunity. We, therefore, show that our method is suited to distinguish the potency of two vaccine candidates with minor structural differences. KW - glycoengineering KW - fucosylation KW - RSV KW - F-protein KW - NanoString Y1 - 2017 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:526-opus4-9831 SN - 2306-5354 VL - 4 IS - 3 ER - TY - JOUR A1 - Sandig, Grit A1 - von Horsten, Hans Henning A1 - Radke, Lars A1 - Blanchard, Véronique A1 - Frohme, Marcus A1 - Giese, Christoph A1 - Sandig, Volker A1 - Hinderlich, Stephan T1 - Engineering of CHO Cells for the Production of Recombinant Glycoprotein Vaccines with Xylosylated N-glycans JF - Bioengineering N2 - Xylose is a general component of O-glycans in mammals. Core-xylosylation of N-glycans is only found in plants and helminth. Consequently, xylosylated N-glycans cause immunological response in humans. We have used the F-protein of the human respiratory syncytial virus (RSV), one of the main causes of respiratory tract infection in infants and elderly, as a model protein for vaccination. The RSV-F protein was expressed in CHO-DG44 cells, which were further modified by co-expression of β1,2-xylosyltransferase from Nicotiana tabacum. Xylosylation of RSV-F N-glycans was shown by monosaccharide analysis and MALDI-TOF mass spectrometry. In immunogenic studies with a human artificial lymph node model, the engineered RSV-F protein revealed improved vaccination efficacy. KW - CHO KW - glycoengineering KW - respiratory syncytial virus KW - vaccine KW - xylose Y1 - 2017 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:526-opus4-9620 SN - 2306-5354 VL - 4 IS - 2 ER - TY - JOUR A1 - Lukose, Rasuole A1 - Lisker, Marco A1 - Akhtar, Fatima A1 - Fraschke, Mirko A1 - Grabolla, T. A1 - Mai, Andreas A1 - Lukosius, Mindaugas T1 - Influence of plasma treatment on SiO2/Si and Si3N4/Si substrates for large-scale transfer of graphene JF - Scientific Reports N2 - One of the limiting factors of graphene integration into electronic, photonic, or sensing devices is the unavailability of large-scale graphene directly grown on the isolators. Therefore, it is necessary to transfer graphene from the donor growth wafers onto the isolating target wafers. In the present research, graphene was transferred from the chemical vapor deposited 200 mm Germanium/Silicon (Ge/Si) wafers onto isolating (SiO2/Si and Si3N4/Si) wafers by electrochemical delamination procedure, employing poly(methylmethacrylate) as an intermediate support layer. In order to influence the adhesion properties of graphene, the wettability properties of the target substrates were investigated in this study. To increase the adhesion of the graphene on the isolating surfaces, they were pre-treated with oxygen plasma prior the transfer process of graphene. The wetting contact angle measurements revealed the increase of the hydrophilicity after surface interaction with oxygen plasma, leading to improved adhesion of the graphene on 200 mm target wafers and possible proof-of-concept development of graphene-based devices in standard Si technologies. Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:526-opus4-14179 SN - 2045-2322 VL - 11 ER - TY - JOUR A1 - Elviretti, M. A1 - Lisker, Marco A1 - Lukose, Rasuole A1 - Lukosius, Mindaugas A1 - Akhtar, Fatima A1 - Mai, Andreas T1 - Reliable metal–graphene contact formation process flows in a CMOS-compatible environment JF - Nanoscale Advances N2 - The possibility of exploiting the enormous potential of graphene for microelectronics and photonics must go through the optimization of the graphene–metal contact. Achieving low contact resistance is essential for the consideration of graphene as a candidate material for electronic and photonic devices. This work has been carried out in an 8′′ wafer pilot-line for the integration of graphene into a CMOS environment. The main focus is to study the impact of the patterning of graphene and passivation on metal–graphene contact resistance. The latter is measured by means of transmission line measurement (TLM) with several contact designs. The presented approaches enable reproducible formation of contact resistivity as low as 660 Ω μm with a sheet resistance of 1.8 kΩ/□ by proper graphene patterning, passivation of the channel and a post-processing treatment such as annealing. Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:526-opus4-16581 VL - 4 SP - 4373 EP - 4380 PB - Royal Society of Chemistry (RSC) ER - TY - JOUR A1 - Bauer, Joachim A1 - Gutke, Marko A1 - Heinrich, Friedhelm A1 - Edling, Matthias A1 - Stoycheva, Vesela A1 - Kaltenbach, Alexander A1 - Burkhardt, Martin A1 - Gruenefeld, Martin A1 - Gamp, Matthias A1 - Gerhard, Christoph A1 - Steglich, Patrick A1 - Steffen, Sebastian A1 - Herzog, Michael A1 - Dreyer, Christian A1 - Schrader, Sigurd T1 - Novel UV-transparent 2-component polyurethane resin for chip-on-board LED micro lenses JF - Optical Materials Express N2 - In this work we present a novel optical polymer system based on polyurethane elastomer components, which combines excellent UV transparency with high thermal stability, good hardness, high surface tension and long pot life. The material looks very promising for encapsulation and microlensing applications for chip-on-board (CoB) light-emitting diodes (LED). The extinction coefficient k, refractive index n, and bandgap parameters were derived from transmission and reflection measurements in a wavelength range of 200-890 nm. Thermogravimetry and differential scanning calorimetry were used to provide glass transition and degradation temperatures. The surface tension was determined by means of contact angle measurements. As proof of concept, a commercial InGaN-CoB-LED is used to demonstrate the suitability of the new material for the production of microlenses. Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:526-opus4-13472 SN - 2159-3930 VL - 10 IS - 9 SP - 2085 EP - 2099 ER - TY - JOUR A1 - Krause, Antje A1 - Stoye, Jens A1 - Vingron, Martin T1 - Large scale hierarchical clustering of protein sequences JF - BMC Bioinformatics N2 - Background: Searching a biological sequence database with a query sequence looking for homologues has become a routine operation in computational biology. In spite of the high degree of sophistication of currently available search routines it is still virtually impossible to identify quickly and clearly a group of sequences that a given query sequence belongs to. Results: We report on our developments in grouping all known protein sequences hierarchically into superfamily and family clusters. Our graph-based algorithms take into account the topology of the sequence space induced by the data itself to construct a biologically meaningful partitioning. We have applied our clustering procedures to a non-redundant set of about 1,000,000 sequences resulting in a hierarchical clustering which is being made available for querying and browsing at http://systers.molgen.mpg.de/. Conclusions: Comparisons with other widely used clustering methods on various data sets show the abilities and strengths of our clustering methods in producing a biologically meaningful grouping of protein sequences. KW - Protein KW - Sequenz KW - Clusteralgorithmus KW - Hierarchisches Clustern KW - Proteinfamilie KW - protein KW - sequence KW - cluster algorithm KW - hierarchical clustering KW - protein family Y1 - 2005 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:526-opus-153 SN - 1471-2105 PB - BioMed Central ER -