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4. Advanced Engineered Wood-Material Concepts

Author

Sandberg, Dick, Gorbacheva, Galina, Lichtenegger, Helga, Niemz, Peter, Teischinger, Alfred, Merkle, Dieter, Managing Editor, Niemz, Peter, editor, Teischinger, Alfred, editor, and Sandberg, Dick, editor

Published
2023
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8. Examination of intestinal ultrastructure, bowel wall apoptosis and tight junctions in the early phase of sepsis.

Author

Obermüller, Beate, Frisina, Noemi, Meischel, Martin, Singer, Georg, Stanzl-Tschegg, Stefanie, Lichtenegger, Helga, Kolb, Dagmar, Klymiuk, Ingeborg, Till, Holger, and Castellani, Christoph

Subjects
Animals, Apoptosis, Cecum, Colon, Disease Models, Animal, Epithelial Cells, Humans, Ileum, Intestinal Mucosa, Intestines, Mice, Permeability, Sepsis, Tight Junctions
Abstract

Gut hyperpermeability can be caused by either apoptosis of the intestinal epithelium or altered status, permeability or porosity of tight junctions. This project aims to elucidate these mechanisms in the early phase of sepsis. Eighteen male wild type mice were randomized to two groups. All mice received one single gavage of fluorescein isothiocyanate (FITC) dextran 30 min before intervention. One group (n = 10) underwent cecal ligation and puncture to induce sepsis. The other group (n = 8) was sham operated. Septic animals exhibited significantly increased permeability for FITC 8 h post-operatively. Significantly increased serum interleukin-6, tumor-necrosis-factor-alpha and interleukin-1-beta confirmed sepsis. Septic animals showed significant bowel wall inflammation of ileum and colon samples. PCR revealed significantly increased expression of claudin-2 and decreased expressions of claudin-4, tight-junction-protein-1 and occludin-1 resembling increased permeability of tight junctions. However, these alterations could not be confirmed at the protein level. Light microscopy revealed significant dilatation of intercellular spaces at the basal sections of intestinal epithelial cells (IEC) in septic animals confirmed by increased intercellular spaces at the level of tight junctions and adherens junctions in electron microscopy (TEM). In small angle X-ray scattering no increase in number or size of nanopores could be shown in the bowel wall. HOECHST staining and PCR of ileum samples for apoptosis markers proofed no relevant differences in intestinal epithelial cell apoptosis between the groups. Intestinal hyperpermeability in septic animals was most likely caused by alterations of the intercellular contacts and not by apoptosis or increased size/number of nanopores of intestinal epithelial cells in this murine model of early sepsis.

Published
2020

11. Energy‐dispersive Laue diffraction analysis of the influence of statherin and histatin on the crystallographic texture during human dental enamel demineralization.

Author

Sakr, Charbel, Al-Mosawi, Mohammed, Grünewald, Tilman A., Cook, Philip, Tack, Pieter, Vincze, Laszlo, Micha, Jean-Sebastien, Anderson, Paul, Al-Jawad, Maisoon, and Lichtenegger, Helga C.

Subjects
DENTAL enamel, CRYSTAL texture, SALIVARY proteins, TOOTH demineralization, PEPTIDES
Abstract

Energy‐dispersive Laue diffraction (EDLD) is a powerful method to obtain position‐resolved texture information in inhomogeneous biological samples without the need for sample rotation. This study employs EDLD texture scanning to investigate the impact of two salivary peptides, statherin (STN) and histatin‐1 (HTN) 21 N‐terminal peptides (STN21 and HTN21), on the crystallographic structure of dental enamel. These proteins are known to play crucial roles in dental caries progression. Three healthy incisors were randomly assigned to three groups: artificially demineralized, demineralized after HTN21 peptide pre‐treatment and demineralized after STN21 peptide pre‐treatment. To understand the micro‐scale structure of the enamel, each specimen was scanned from the enamel surface to a depth of 250 µm using microbeam EDLD. Via the use of a white beam and a pixelated detector, where each pixel functions as a spectrometer, pole figures were obtained in a single exposure at each measurement point. The results revealed distinct orientations of hydroxyapatite crystallites and notable texture variation in the peptide‐treated demineralized samples compared with the demineralized control. Specifically, the peptide‐treated demineralized samples exhibited up to three orientation populations, in contrast to the demineralized control which displayed only a single orientation population. The texture index of the demineralized control (2.00 ± 0.21) was found to be lower than that of either the STN21 (2.32 ± 0.20) or the HTN21 (2.90 ± 0.46) treated samples. Hence, texture scanning with EDLD gives new insights into dental enamel crystallite orientation and links the present understanding of enamel demineralization to the underlying crystalline texture. For the first time, the feasibility of EDLD texture measurements for quantitative texture evaluation in demineralized dental enamel samples is demonstrated. [ABSTRACT FROM AUTHOR]

Published
2024
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12. Comparative Analysis of Various Spider Silks in Regard to Nerve Regeneration: Material Properties and Schwann Cell Response (Adv. Healthcare Mater. 8/2024)

Author

Stadlmayr, Sarah, primary, Peter, Karolina, additional, Millesi, Flavia, additional, Rad, Anda, additional, Wolf, Sonja, additional, Mero, Sascha, additional, Zehl, Martin, additional, Mentler, Axel, additional, Gusenbauer, Claudia, additional, Konnerth, Johannes, additional, Schniepp, Hannes C., additional, Lichtenegger, Helga, additional, Naghilou, Aida, additional, and Radtke, Christine, additional

Published
2024
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15. Comparative Analysis of Various Spider Silks in Regard to Nerve Regeneration: Material Properties and Schwann Cell Response

Author

Stadlmayr, Sarah, primary, Peter, Karolina, additional, Millesi, Flavia, additional, Rad, Anda, additional, Wolf, Sonja, additional, Mero, Sascha, additional, Zehl, Martin, additional, Mentler, Axel, additional, Gusenbauer, Claudia, additional, Konnerth, Johannes, additional, Schniepp, Hannes C., additional, Lichtenegger, Helga, additional, Naghilou, Aida, additional, and Radtke, Christine, additional

Published
2023
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28. 3D nanoscale analysis of bone healing around degrading Mg implants evaluated by X-ray scattering tensor tomography

Author

Liebi, Marianne, primary, Lutz-Bueno, Viviane, additional, Guizar-Sicairos, Manuel, additional, Schönbauer, Bernd M., additional, Eichler, Johannes, additional, Martinelli, Elisabeth, additional, Löffler, Jörg F., additional, Weinberg, Annelie, additional, Lichtenegger, Helga, additional, and Grünewald, Tilman A., additional

Published
2021
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29. Polymers / Solvent-free Ultrasonic Dispersion of Nanofillers in Epoxy Matrix

Author

Zanghellini, Benjamin, Knaack, Patrick, Schörpf, Sebastian, Semlitsch, Karl-Heinz, Lichtenegger, Helga C., Praher, Bernhard, Omastova, Maria, and Rennhofer, Harald

Subjects
carbon nanotubes, functionalization, Rheologie, dispersion, rheology, Ultraschall, ultrasonication, Funktionalisierung
Abstract

Dispersion of carbon nanotubes and carbon nanofibers is a crucial processing step in the production of polymer-based nanocomposites and poses a great challenge due to the tendency of nanofillers to agglomerate. One of the most effective methods for dispersion is the use of a three-roll mill, which is a well-established method and results in agglomerates below 5 m. Nevertheless, this process is time-consuming and thus a limiting factor for industrial applications. Our aim was to establish an easy and efficient ultrasonic dispersion process, characterize the dispersion parameters, and compare both methods, ultrasonication and the three-roll mill. We applied rheological tests and analyzed the agglomerate sizes by an image fit of the microscopy images. All these analyses combined deliver a valuable set of information about the dispersions quality and, therefore, allows the improvement and further adaptation of the dispersion process. (VLID)5734995

Published
2021

32. Poly(ester amide)s from poly(alkylene succinate)s and rapid crystallizing amido diols

Author

Kluge, Marcel, Rennhofer, Harald, Lichtenegger, Helga C., Liebner, Falk W., Robert, Tobias, and Publica

Subjects
bio-based polymers, thermal properties, microstructure, poly(ester amide), succinic acid, amido diol
Abstract

Random poly(ester amide)s are synthesized from succinic acid, ethylene glycol or 1,4-butanediol and different aliphatic amido diols - symmetric a,o-diols containing two amide moieties. The formation of chain-terminating N-succinimide end groups, which limit the molecular weight attainable by common synthetic strategies, is effectively suppressed. Poly(ester amide)s crystallize in a suprastructure similar to that of even-even polyamides. The thermal properties of both types of poly(ester amide)s synthesized are considerably improved and transition temperatures are tunable by changing the ratio of aliphatic diol to rapidly crystallizing amido diol in the feed. Using ethylene glycol as diol component, Tg and Tm of the material could be enhanced from −12 to −2 °C and 97 to 157 °C, respectively, while an increase from −33 to −8 °C and 115-153 °C was observed for their 1,4-butanediol derived counterparts. Furthermore, the slow crystallization rate of poly(ethylene succinate) from molten state could be significantly accelerated by the introduction of amide moieties into the polymer backbone.

Published
2020

49. Strain Hardening and Pore Size Harmonization by Uniaxial Densification: A Facile Approach toward Superinsulating Aerogels from Nematic Nanofibrillated 2,3-Dicarboxyl Cellulose

Author

Plappert, Sven, Nedelec, J.-M., Rennhofer, Harald, Lichtenegger, Helga, Liebner, Falk, Department of Chemistry, Division of Chemistry of Renewables, University of Natural Resources and Life Sciences Vienna, Vienna, Institut de Chimie de Clermont-Ferrand (ICCF), SIGMA Clermont (SIGMA Clermont)-Institut de Chimie du CNRS (INC)-Université Clermont Auvergne [2017-2020] (UCA [2017-2020])-Centre National de la Recherche Scientifique (CNRS), University of Natural Resources and Life Sciences (BOKU), Institute of Physics and Materials Science, University of Natural Resources and Life Sciences Vienna, Department of Chemistry, Universität für Bodenkultur Wien [Vienne, Autriche] (BOKU), Nedelec, Jean-Marie, and Universität für Bodenkultur Wien = University of Natural Resources and Life [Vienne, Autriche] (BOKU)

Subjects
[CHIM.MATE] Chemical Sciences/Material chemistry, [CHIM.MATE]Chemical Sciences/Material chemistry, ComputingMilieux_MISCELLANEOUS
Abstract

International audience

Published
2017

50. Acid Free Oxidation and Simple Dispersion Method of MWCNT for High-Performance CFRP

Author

Singer, Gerald, primary, Siedlaczek, Philipp, additional, Sinn, Gerhard, additional, Rennhofer, Harald, additional, Mičušík, Matej, additional, Omastová, Maria, additional, Unterlass, Miriam, additional, Wendrinsky, Josef, additional, Milotti, Valeria, additional, Fedi, Filippo, additional, Pichler, Thomas, additional, and Lichtenegger, Helga, additional

Published
2018
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