7 results on '"Neusius D"'
Search Results
2. 3D Image Based Structural Analysis of Leather for Macroscopic Structure- Property Simulation
- Author
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Dietrich, Sascha, Schulz, H., Hauch, K., Schladitz, K., Godehardt, M., Orlik, J., Neusius, D., and International Union of Leather Technologists and Chemists Societies
- Subjects
ddc:621.3 ,leather structure, 3D, image analyses, simulation ,ddc:620 - Abstract
Content: The intrinsic structure significantly influences the mechanical properties of leather. In consequence, knowledge of leather’s hierarchical structure is essential in order to find the most suited leather for specific application. Leather structure based parameters are of major importance for both manufacturing and leather processing industries. In this respect, intensive structure investigations have been subjected in continuous research work. Quantitative image analysis combined with stochastic micro-structure modelling and numerical simulation of macroscopic properties is a promising approach to gain a deeper understanding of complex relations between material’s micro-structure geometry and macroscopic properties. Key ingredient is a reliable geometric description provided by the quantitative analysis of 3D images of the material micro-structures. For leather, both imaging and image analysis are particularly challenging, due to the multi-scale nature of the leather’s micro-structure. Scales in leather are not well separated. Previously, high resolution computed tomography allowed 3D imaging of purely vegetable tanned leather samples at micro- and submicro- scale. Segmentation of leather structure as well as of typical structural elements in resulting image data is however hampered by a strong heterogeneity caused by lower scale structural information. The first method for automatic segmentation of typical structural elements at varying scales combined morphological smoothing with defining and iteratively coarsening regions using the waterfall algorithm on local orientations. It yields a hierarchical segmentation of the leather into coarse and fine structural elements that can be used to analyze and compare the structure of leather samples. Size and shape of the structural elements as well as their sub-structure yield information, e. g. on undulation, branching, thickness, cross-sectional shape, and preferred directions. In order to compare the micro-structure of leather samples from various body parts or even species, the segmentation has to be applicable without extensive pre-processing and parameter tuning. Robustness can be gained by applying smoothing methods that are adapted to the goal of defining image regions by similar local orientation. The challenge is that the space of fiber orientations in 3D is not equipped with an order. Motivated by a recent approach for nevertheless defining erosion and dilation on the sphere, we suggest new definitions for these morphological base transformations on the space of directions in 3D. We present segmentation results for 3D images of leather samples derived by these new morphological smoothing methods. Take-Away: The intrinsic structure significantly influences the mechanical properties of leather. Leather’s hierarchical structure can be analyzed by quantitative 3D image analysis combined with stochastic micro-structure modelling. Segmentation results for 3D images of leather samples derived by new morphological smoothing methods.
- Published
- 2019
3. Extension of One-Dimensional Models for Hyperelastic String Structures under Coulomb Friction with Adhesion
- Author
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Shiryaev, V., Neusius, D., Orlik, J., and Publica
- Subjects
textile modeling ,Coulomb friction ,hyperelastic strings ,lcsh:Q ,lcsh:Science ,Capstan law with adhesion - Abstract
A stretching behavior of knitted and woven textiles is modeled. In our work, the yarns are modeled as one-dimensional hyperelastic strings with frictional contact. Capstan law known for Coulomb's friction of yarns is extended to an additional adhesion due to gluing of filaments on the yarn surface or some chemical reaction. Two-step Newton's method is applied for the solution of the large stretching with sliding evolution in the contact nodes. The approach is illustrated on a hysteresis of knitted textile and on the force-strain curve for a woven pattern and both compared with experimental effective curves.
- Published
- 2018
4. A Cartesian cut-cell method for the isothermal compressible viscous Navier-Stokes equations
- Author
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Neusius, D. and Schmidt, S.
- Published
- 2013
- Full Text
- View/download PDF
5. NTRC regulates CP12 to activate Calvin-Benson cycle during cold acclimation.
- Author
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Teh JT, Leitz V, Holzer VJC, Neusius D, Marino G, Meitzel T, García-Cerdán JG, Dent RM, Niyogi KK, Geigenberger P, and Nickelsen J
- Subjects
- Acclimatization, Glyceraldehyde-3-Phosphate Dehydrogenases metabolism, Oxidation-Reduction, Photosynthesis physiology, Thioredoxin-Disulfide Reductase metabolism, Chlamydomonas reinhardtii
- Abstract
NADPH-dependent thioredoxin reductase C (NTRC) is a chloroplast redox regulator in algae and plants. Here, we used site-specific mutation analyses of the thioredoxin domain active site of NTRC in the green alga Chlamydomonas reinhardtii to show that NTRC mediates cold tolerance in a redox-dependent manner. By means of coimmunoprecipitation and mass spectrometry, a redox- and cold-dependent binding of the Calvin-Benson Cycle Protein 12 (CP12) to NTRC was identified. NTRC was subsequently demonstrated to directly reduce CP12 of C. reinhardtii as well as that of the vascular plant Arabidopsis thaliana in vitro. As a scaffold protein, CP12 joins the Calvin-Benson cycle enzymes phosphoribulokinase (PRK) and glyceraldehyde-3-phosphate dehydrogenase (GAPDH) to form an autoinhibitory supracomplex. Using size-exclusion chromatography, NTRC from both organisms was shown to control the integrity of this complex in vitro and thereby PRK and GAPDH activities in the cold. Thus, NTRC apparently reduces CP12, hence triggering the dissociation of the PRK/CP12/GAPDH complex in the cold. Like the ntrc::aphVIII mutant, CRISPR-based cp12::emx1 mutants also exhibited a redox-dependent cold phenotype. In addition, CP12 deletion resulted in robust decreases in both PRK and GAPDH protein levels implying a protein protection effect of CP12. Both CP12 functions are critical for preparing a repertoire of enzymes for rapid activation in response to environmental changes. This provides a crucial mechanism for cold acclimation.
- Published
- 2023
- Full Text
- View/download PDF
6. Lysine acetylation regulates moonlighting activity of the E2 subunit of the chloroplast pyruvate dehydrogenase complex in Chlamydomonas.
- Author
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Neusius D, Kleinknecht L, Teh JT, Ostermeier M, Kelterborn S, Eirich J, Hegemann P, Finkemeier I, Bohne AV, and Nickelsen J
- Subjects
- Acetylation, Carbon metabolism, Chloroplasts metabolism, Dihydrolipoyllysine-Residue Acetyltransferase metabolism, Lysine metabolism, Photosystem II Protein Complex metabolism, Pyruvate Dehydrogenase Complex metabolism, RNA, Messenger genetics, RNA, Messenger metabolism, Ribonucleoproteins metabolism, Chlamydomonas metabolism, Chlamydomonas reinhardtii genetics, Chlamydomonas reinhardtii metabolism
- Abstract
The dihydrolipoamide acetyltransferase subunit DLA2 of the chloroplast pyruvate dehydrogenase complex (cpPDC) in the green alga Chlamydomonas reinhardtii has previously been shown to possess moonlighting activity in chloroplast gene expression. Under mixotrophic growth conditions, DLA2 forms part of a ribonucleoprotein particle (RNP) with the psbA mRNA that encodes the D1 protein of the photosystem II (PSII) reaction center. Here, we report on the characterization of the molecular switch that regulates shuttling of DLA2 between its functions in carbon metabolism and D1 synthesis. Determination of RNA-binding affinities by microscale thermophoresis demonstrated that the E3-binding domain (E3BD) of DLA2 mediates psbA-specific RNA recognition. Analyses of cpPDC formation and activity, as well as RNP complex formation, showed that acetylation of a single lysine residue (K197) in E3BD induces the release of DLA2 from the cpPDC, and its functional shift towards RNA binding. Moreover, Förster resonance energy transfer microscopy revealed that psbA mRNA/DLA2 complexes localize around the chloroplast's pyrenoid. Pulse labeling and D1 re-accumulation after induced PSII degradation strongly suggest that DLA2 is important for D1 synthesis during de novo PSII biogenesis., (© 2022 The Authors. The Plant Journal published by Society for Experimental Biology and John Wiley & Sons Ltd.)
- Published
- 2022
- Full Text
- View/download PDF
7. Simulation of Leather Visco-Elastic Behavior Based on Collagen Fiber-Bundle Properties and a Meso-Structure Network Model.
- Author
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Dietrich S, Lykhachova O, Cheng X, Godehardt M, Kronenberger M, Meyer M, Neusius D, Orlik J, Schladitz K, Schulz H, Steiner K, and Voigt D
- Abstract
Simulation-based prediction of mechanical properties is highly desirable for optimal choice and treatment of leather. Nowadays, this is state-of-the-art for many man-made materials. For the natural material leather, this task is however much more demanding due to the leather's high variability and its extremely intricate structure. Here, essential geometric features of the leather's meso-scale are derived from 3D images obtained by micro-computed tomography and subsumed in a parameterizable structural model. That is, the fiber-bundle structure is modeled. The structure model is combined with bundle properties derived from tensile tests. Then the effective leather visco-elastic properties are simulated numerically in the finite element representation of the bundle structure model with sliding contacts between bundles. The simulation results are validated experimentally for two animal types, several tanning procedures, and varying sample positions within the hide. Finally, a complete workflow for assessing leather quality by multi-scale simulation of elastic and visco-elastic properties is established and validated.
- Published
- 2021
- Full Text
- View/download PDF
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