@article{RigortGuentherHegerletal.2012, author = {Rigort, Alexander and G{\"u}nther, David and Hegerl, Reiner and Baum, Daniel and Weber, Britta and Prohaska, Steffen and Medalia, Ohad and Baumeister, Wolfgang and Hege, Hans-Christian}, title = {Automated segmentation of electron tomograms for a quantitative description of actin filament networks}, series = {Journal of Structural Biology}, volume = {177}, journal = {Journal of Structural Biology}, doi = {10.1016/j.jsb.2011.08.012}, pages = {135 -- 144}, year = {2012}, language = {en} } @inproceedings{HombergBaumProhaskaetal.2012, author = {Homberg, Ulrike and Baum, Daniel and Prohaska, Steffen and Kalbe, Ute and Witt, Karl Josef}, title = {Automatic Extraction and Analysis of Realistic Pore Structures from µCT Data for Pore Space Characterization of Graded Soil}, series = {Proceedings of the 6th International Conference on Scour and Erosion (ICSE-6)}, booktitle = {Proceedings of the 6th International Conference on Scour and Erosion (ICSE-6)}, pages = {345 -- 352}, year = {2012}, language = {en} } @article{WeberGreenanProhaskaetal.2012, author = {Weber, Britta and Greenan, Garrett and Prohaska, Steffen and Baum, Daniel and Hege, Hans-Christian and M{\"u}ller-Reichert, Thomas and Hyman, Anthony and Verbavatz, Jean-Marc}, title = {Automated tracing of microtubules in electron tomograms of plastic embedded samples of Caenorhabditis elegans embryos}, series = {Journal of Structural Biology}, volume = {178}, journal = {Journal of Structural Biology}, number = {2}, doi = {10.1016/j.jsb.2011.12.004}, pages = {129 -- 138}, year = {2012}, language = {en} } @article{KleinfeldBhariokeBlinderetal.2011, author = {Kleinfeld, David and Bharioke, Arjun and Blinder, Pablo and Bock, David and Briggman, Kevin and Chklovskii, Dmitri and Denk, Winfried and Helmstaedter, Moritz and Kaufhold, John and Lee, Wei-Chung and Meyer, Hanno and Micheva, Kristina and Oberlaender, Marcel and Prohaska, Steffen and Reid, R. and Smith, Stephen and Takemura, Shinya and Tsai, Philbert and Sakmann, Bert}, title = {Large-scale automated histology in the pursuit of connectomes}, series = {Journal of Neuroscience}, volume = {31}, journal = {Journal of Neuroscience}, number = {45}, doi = {10.1523/JNEUROSCI.4077-11.2011}, pages = {16125 -- 16138}, year = {2011}, language = {en} } @article{LindowBaumProhaskaetal.2010, author = {Lindow, Norbert and Baum, Daniel and Prohaska, Steffen and Hege, Hans-Christian}, title = {Accelerated Visualization of Dynamic Molecular Surfaces}, series = {Comput. Graph. Forum}, volume = {29}, journal = {Comput. Graph. Forum}, doi = {10.1111/j.1467-8659.2009.01693.x}, pages = {943 -- 952}, year = {2010}, language = {en} } @inproceedings{ReininghausGuentherHotzetal.2010, author = {Reininghaus, Jan and G{\"u}nther, David and Hotz, Ingrid and Prohaska, Steffen and Hege, Hans-Christian}, title = {TADD: A Computational Framework for Data Analysis Using Discrete Morse Theory}, series = {Mathematical Software - ICMS 2010}, volume = {6327}, booktitle = {Mathematical Software - ICMS 2010}, publisher = {Springer}, doi = {10.1007/978-3-642-15582-6_35}, pages = {198 -- 208}, year = {2010}, language = {en} } @article{KussGenselMeyeretal.2010, author = {Kuß, Anja and Gensel, Maria and Meyer, Bj{\"o}rn and Dercksen, Vincent J. and Prohaska, Steffen}, title = {Effective Techniques to Visualize Filament-Surface Relationships}, series = {Comput. Graph. Forum}, volume = {29}, journal = {Comput. Graph. Forum}, pages = {1003 -- 1012}, year = {2010}, language = {en} } @misc{HombergBaumWiebeletal.2014, author = {Homberg, Ulrike and Baum, Daniel and Wiebel, Alexander and Prohaska, Steffen and Hege, Hans-Christian}, title = {Definition, Extraction, and Validation of Pore Structures in Porous Materials}, series = {Topological Methods in Data Analysis and Visualization III}, journal = {Topological Methods in Data Analysis and Visualization III}, editor = {Bremer, Peer-Timo and Hotz, Ingrid and Pascucci, Valerio and Peikert, Ronald}, publisher = {Springer}, doi = {10.1007/978-3-319-04099-8_15}, pages = {235 -- 248}, year = {2014}, language = {en} } @inproceedings{RosanwoPetzProhaskaetal.2009, author = {Rosanwo, Olufemi and Petz, Christoph and Prohaska, Steffen and Hotz, Ingrid and Hege, Hans-Christian}, title = {Dual Streamline Seeding}, series = {Proceedings of the IEEE Pacific Visualization Symposium}, booktitle = {Proceedings of the IEEE Pacific Visualization Symposium}, editor = {Eades, Peter and Ertl, Thomas and Shen, Han-Wei}, address = {Beijing, China}, pages = {9 -- 16}, year = {2009}, language = {en} } @inproceedings{HombergBinnerProhaskaetal.2009, author = {Homberg, Ulrike and Binner, Richard and Prohaska, Steffen and Dercksen, Vincent J. and Kuß, Anja and Kalbe, Ute}, title = {Determining Geometric Grain Structure from X-Ray Micro-Tomograms of Gradated Soil}, series = {Workshop Internal Erosion}, volume = {21}, booktitle = {Workshop Internal Erosion}, pages = {37 -- 52}, year = {2009}, language = {en} } @inproceedings{PaetschBaumProhaskaetal., author = {Paetsch, Olaf and Baum, Daniel and Prohaska, Steffen and Ehrig, Karsten and Meinel, Dietmar and Ebell, Gino}, title = {3D Corrosion Detection in Time-dependent CT Images of Concrete}, series = {DIR-2015 Proceedings}, booktitle = {DIR-2015 Proceedings}, abstract = {In civil engineering, the corrosion of steel reinforcements in structural elements of concrete bares a risk of stability-reduction, mainly caused by the exposure to chlorides. 3D computed tomography (CT) reveals the inner structure of concrete and allows one to investigate the corrosion with non-destructive testing methods. To carry out such investigations, specimens with a large artificial crack and an embedded steel rebar have been manufactured. 3D CT images of those specimens were acquired in the original state. Subsequently three cycles of electrochemical pre-damaging together with CT imaging were applied. These time series have been evaluated by means of image processing algorithms to segment and quantify the corrosion products. Visualization of the results supports the understanding of how corrosion propagates into cracks and pores. Furthermore, pitting of structural elements can be seen without dismantling. In this work, several image processing and visualization techniques are presented that have turned out to be particularly effective for the visualization and segmentation of corrosion products. Their combination to a workflow for corrosion analysis is the main contribution of this work.}, language = {en} } @misc{HombergBaumWiebeletal., author = {Homberg, Ulrike and Baum, Daniel and Wiebel, Alexander and Prohaska, Steffen and Hege, Hans-Christian}, title = {Definition, Extraction, and Validation of Pore Structures in Porous Materials}, issn = {1438-0064}, url = {http://nbn-resolving.de/urn:nbn:de:0297-zib-42510}, abstract = {An intuitive and sparse representation of the void space of porous materials supports the efficient analysis and visualization of interesting qualitative and quantitative parameters of such materials. We introduce definitions of the elements of this void space, here called pore space, based on its distance function, and present methods to extract these elements using the extremal structures of the distance function. The presented methods are implemented by an image processing pipeline that determines pore centers, pore paths and pore constrictions. These pore space elements build a graph that represents the topology of the pore space in a compact way. The representations we derive from μCT image data of realistic soil specimens enable the computation of many statistical parameters and, thus, provide a basis for further visual analysis and application-specific developments. We introduced parts of our pipeline in previous work. In this chapter, we present additional details and compare our results with the analytic computation of the pore space elements for a sphere packing in order to show the correctness of our graph computation.}, language = {en} } @misc{HombergBaumProhaskaetal., author = {Homberg, Ulrike and Baum, Daniel and Prohaska, Steffen and G{\"u}nster, Jens and Krauß-Sch{\"u}ler, Stefanie}, title = {Adapting trabecular structures for 3D printing: an image processing approach based on µCT data}, issn = {1438-0064}, url = {http://nbn-resolving.de/urn:nbn:de:0297-zib-64004}, abstract = {Materials with a trabecular structure notably combine advantages such as lightweight, reasonable strength, and permeability for fluids. This combination of advantages is especially interesting for tissue engineering in trauma surgery and orthopedics. Bone-substituting scaffolds for instance are designed with a trabecular structure in order to allow cell migration for bone ingrowth and vascularization. An emerging and recently very popular technology to produce such complex, porous structures is 3D printing. However, several technological aspects regarding the scaffold architecture, the printable resolution, and the feature size have to be considered when fabricating scaffolds for bone tissue replacement and regeneration. Here, we present a strategy to assess and prepare realistic trabecular structures for 3D printing using image analysis with the aim of preserving the structural elements. We discuss critical conditions of the printing system and present a 3-stage approach to adapt a trabecular structure from \$\mu\$CT data while incorporating knowledge about the printing system. In the first stage, an image-based extraction of solid and void structures is performed, which results in voxel- and graph-based representations of the extracted structures. These representations not only allow us to quantify geometrical properties such as pore size or strut geometry and length. But, since the graph represents the geometry and the topology of the initial structure, it can be used in the second stage to modify and adjust feature size, volume and sample size in an easy and consistent way. In the final reconstruction stage, the graph is then converted into a voxel representation preserving the topology of the initial structure. This stage generates a model with respect to the printing conditions to ensure a stable and controlled voxel placement during the printing process.}, language = {en} } @article{RedemannBaumgartLindowetal.2017, author = {Redemann, Stefanie and Baumgart, Johannes and Lindow, Norbert and Shelley, Michael and Nazockdast, Ehssan and Kratz, Andrea and Prohaska, Steffen and Brugu{\´e}s, Jan and F{\"u}rthauer, Sebastian and M{\"u}ller-Reichert, Thomas}, title = {C. elegans chromosomes connect to centrosomes by anchoring into the spindle network}, series = {Nature Communications}, volume = {8}, journal = {Nature Communications}, number = {15288}, doi = {10.1038/ncomms15288}, year = {2017}, abstract = {The mitotic spindle ensures the faithful segregation of chromosomes. Here we combine the first large-scale serial electron tomography of whole mitotic spindles in early C. elegans embryos with live-cell imaging to reconstruct all microtubules in 3D and identify their plus- and minus-ends. We classify them as kinetochore (KMTs), spindle (SMTs) or astral microtubules (AMTs) according to their positions, and quantify distinct properties of each class. While our light microscopy and mutant studies show that microtubules are nucleated from the centrosomes, we find only a few KMTs directly connected to the centrosomes. Indeed, by quantitatively analysing several models of microtubule growth, we conclude that minus-ends of KMTs have selectively detached and depolymerized from the centrosome. In toto, our results show that the connection between centrosomes and chromosomes is mediated by an anchoring into the entire spindle network and that any direct connections through KMTs are few and likely very transient.}, language = {en} } @article{HombergBaumProhaskaetal., author = {Homberg, Ulrike and Baum, Daniel and Prohaska, Steffen and G{\"u}nster, Jens and Krauß-Sch{\"u}ler, Stefanie}, title = {Adapting trabecular structures for 3D printing: an image processing approach based on µCT data}, series = {Biomedical Physics \& Engineering Express}, volume = {3}, journal = {Biomedical Physics \& Engineering Express}, number = {3}, publisher = {IOP Publishing}, doi = {10.1088/2057-1976/aa7611}, abstract = {Materials with a trabecular structure notably combine advantages such as lightweight, reasonable strength, and permeability for fluids. This combination of advantages is especially interesting for tissue engineering in trauma surgery and orthopedics. Bone-substituting scaffolds for instance are designed with a trabecular structure in order to allow cell migration for bone ingrowth and vascularization. An emerging and recently very popular technology to produce such complex, porous structures is 3D printing. However, several technological aspects regarding the scaffold architecture, the printable resolution, and the feature size have to be considered when fabricating scaffolds for bone tissue replacement and regeneration. Here, we present a strategy to assess and prepare realistic trabecular structures for 3D printing using image analysis with the aim of preserving the structural elements. We discuss critical conditions of the printing system and present a 3-stage approach to adapt a trabecular structure from \$\mu\$CT data while incorporating knowledge about the printing system. In the first stage, an image-based extraction of solid and void structures is performed, which results in voxel- and graph-based representations of the extracted structures. These representations not only allow us to quantify geometrical properties such as pore size or strut geometry and length. But, since the graph represents the geometry and the topology of the initial structure, it can be used in the second stage to modify and adjust feature size, volume and sample size in an easy and consistent way. In the final reconstruction stage, the graph is then converted into a voxel representation preserving the topology of the initial structure. This stage generates a model with respect to the printing conditions to ensure a stable and controlled voxel placement during the printing process.}, language = {en} } @misc{ZhukovaHiepenKnausetal., author = {Zhukova, Yulia and Hiepen, Christian and Knaus, Petra and Osterland, Marc and Prohaska, Steffen and Dunlop, John W. C. and Fratzl, Peter and Skorb, Ekaterina V.}, title = {The role of titanium surface nanotopography on preosteoblast morphology, adhesion and migration}, issn = {1438-0064}, doi = {10.1002/adhm.201601244}, url = {http://nbn-resolving.de/urn:nbn:de:0297-zib-63053}, abstract = {Surface structuring of titanium-based implants with appropriate nanotopographies can significantly modulate their impact on the biological behavior of cells populating these implants. Implant assisted bone tissue repair and regeneration require functional adhesion and expansion of bone progenitors. The surface nanotopography of implant materials used to support bone healing and its effect on cell behavior, in particular cell adhesion, spreading, expansion, and motility, is still not clearly understood. The aim of this study is to investigate preosteoblast proliferation, adhesion, morphology, and migration on different titanium materials with similar surface chemistry, but distinct nanotopographical features. Sonochemical treatment and anodic oxidation were employed to fabricate disordered - mesoporous titania (TMS), and ordered - titania nanotubular (TNT) topographies respectively. The morphological evaluation revealed a surface dependent shape, thickness, and spreading of cells owing to different adherence behavior. Cells were polygonal-shaped and well-spread on glass and TMS, but displayed an elongated fibroblast-like morphology on TNT surfaces. The cells on glass however, were much flatter than on nanostructured surfaces. Both nanostructured surfaces impaired cell adhesion, but TMS was more favorable for cell growth due to its support of cell attachment and spreading in contrast to TNT. Quantitative wound healing assay in combination with live-cell imaging revealed that cells seeded on TMS surfaces migrated in close proximity to neighboring cells and less directed when compared to the migratory behavior on other surfaces. The results indicate distinctly different cell adhesion and migration on ordered and disordered titania nanotopographies, providing important information that could be used in optimizing titanium-based scaffold design to foster bone tissue growth and repair.}, language = {en} } @article{PaetschBaumProhaskaetal., author = {Paetsch, Olaf and Baum, Daniel and Prohaska, Steffen and Ehrig, Karsten and Ebell, Gino and Meinel, Dietmar and Heyn, Andreas}, title = {Korrosionsverfolgung in 3D-computertomographischen Aufnahmen von Stahlbetonproben}, series = {DGZfP-Jahrestagung 2014 Konferenzband}, journal = {DGZfP-Jahrestagung 2014 Konferenzband}, language = {de} } @article{KnoetelSeidelProhaskaetal., author = {Kn{\"o}tel, David and Seidel, Ronald and Prohaska, Steffen and Dean, Mason N. and Baum, Daniel}, title = {Automated Segmentation of Complex Patterns in Biological Tissues: Lessons from Stingray Tessellated Cartilage}, series = {PLOS ONE}, journal = {PLOS ONE}, doi = {10.1371/journal.pone.0188018}, abstract = {Introduction - Many biological structures show recurring tiling patterns on one structural level or the other. Current image acquisition techniques are able to resolve those tiling patterns to allow quantitative analyses. The resulting image data, however, may contain an enormous number of elements. This renders manual image analysis infeasible, in particular when statistical analysis is to be conducted, requiring a larger number of image data to be analyzed. As a consequence, the analysis process needs to be automated to a large degree. In this paper, we describe a multi-step image segmentation pipeline for the automated segmentation of the calcified cartilage into individual tesserae from computed tomography images of skeletal elements of stingrays. Methods - Besides applying state-of-the-art algorithms like anisotropic diffusion smoothing, local thresholding for foreground segmentation, distance map calculation, and hierarchical watershed, we exploit a graph-based representation for fast correction of the segmentation. In addition, we propose a new distance map that is computed only in the plane that locally best approximates the calcified cartilage. This distance map drastically improves the separation of individual tesserae. We apply our segmentation pipeline to hyomandibulae from three individuals of the round stingray (Urobatis halleri), varying both in age and size. Results - Each of the hyomandibula datasets contains approximately 3000 tesserae. To evaluate the quality of the automated segmentation, four expert users manually generated ground truth segmentations of small parts of one hyomandibula. These ground truth segmentations allowed us to compare the segmentation quality w.r.t. individual tesserae. Additionally, to investigate the segmentation quality of whole skeletal elements, landmarks were manually placed on all tesserae and their positions were then compared to the segmented tesserae. With the proposed segmentation pipeline, we sped up the processing of a single skeletal element from days or weeks to a few hours.}, language = {en} } @misc{KnoetelSeidelZaslanskyetal., author = {Kn{\"o}tel, David and Seidel, Ronald and Zaslansky, Paul and Prohaska, Steffen and Dean, Mason N. and Baum, Daniel}, title = {Automated Segmentation of Complex Patterns in Biological Tissues: Lessons from Stingray Tessellated Cartilage (Supplementary Material)}, doi = {10.12752/4.DKN.1.0}, abstract = {Supplementary data to reproduce and understand key results from the related publication, including original image data and processed data. In particular, sections from hyomandibulae harvested from specimens of round stingray Urobatis halleri, donated from another study (DOI: 10.1002/etc.2564). Specimens were from sub-adults/adults collected by beach seine from collection sites in San Diego and Seal Beach, California, USA. The hyomandibulae were mounted in clay, sealed in ethanol-humidified plastic tubes and scanned with a Skyscan 1172 desktop μCT scanner (Bruker μCT, Kontich, Belgium) in association with another study (DOI: 10.1111/joa.12508). Scans for all samples were performed with voxel sizes of 4.89 μm at 59 kV source voltage and 167 μA source current, over 360◦ sample 120 rotation. For our segmentations, the datasets were resampled to a voxel size of 9.78 μm to reduce the size of the images and speed up processing. In addition, the processed data that was generated with the visualization software Amira with techniques described in the related publication based on the mentioned specimens.}, language = {en} } @misc{LindowRedemannFabigetal., author = {Lindow, Norbert and Redemann, Stefanie and Fabig, Gunar and M{\"u}ller-Reichert, Thomas and Prohaska, Steffen}, title = {Quantification of Three-Dimensional Spindle Architecture}, issn = {1438-0064}, url = {http://nbn-resolving.de/urn:nbn:de:0297-zib-66562}, abstract = {Mitotic and meiotic spindles are microtubule-based structures to faithfully segregate chromosomes. Electron tomography is currently the method of choice to analyze the three-dimensional architecture of both types of spindles. Over the years, we have developed methods and software for automatic segmentation and stitching of microtubules in serial sections for large-scale reconstructions. Three-dimensional reconstruction of microtubules, however, is only the first step towards biological insight. The second step is the analysis of the structural data to derive measurable spindle properties. Here, we present a comprehensive set of techniques to quantify spindle parameters. These techniques provide quantitative analyses of specific microtubule classes and are applicable to a variety of tomographic reconstructions of spindles from different organisms.}, language = {en} }