| 1. |
- Galli, Silvia, et al.
(författare)
-
Evaluation of the degradation behavior of resorbable metal implants for in vivo osteosynthesis by synchrotron radiation based x-ray tomography and histology
- 2016
-
Ingår i: Developments in X-Ray Tomography X. - : SPIE - International Society for Optical Engineering.
-
Konferensbidrag (refereegranskat)abstract
- Magnesium(Mg)-alloys are promising candidates as temporary implants for orthopedic and cranio-facial applications. They can sustain tissues during healing, thanks to favorable mechanical properties, and then they slowly degrade into biocompatible products, avoiding the need of a second surgery for implant removal. They have the potential to benefit a vast number of patients, especially children and elderly patients. However, to be able to tailor their degradation to match the speed of tissue regeneration it is crucial to understand how they actually degrade in the living organism. We utilized high-resolution synchrotron-based tomography at the beamline P05 operated by HZG at the storage ring PETRA III at DESY to study the degradation of 3 novel Mg-alloys in rat bone and the consequent bone response. On three-dimensional reconstructions of the bone-implant explants we were able to follow the dynamic transformation that the materials underwent at different healing times and on the basis of absorption coefficients we could distinguish and quantify the amount of remaining implants, the corrosion layers and the new bone. This was a great advantage compared to laboratory CT, for which the limitation in contrast and in resolution made impossible to discriminate between original alloy, degradation products and bone, leading to inaccurate determination of the materials degradation rates. The same samples imaged by tomography were used for non-decalcified histology. The combination of histological and tomographical images provided new insight on the nature of the bone-to-implant interface and of the degradation products, which appeared to have great similarities to the host bone.
|
|
| 2. |
- Moosmann, Julian, et al.
(författare)
-
A load frame for in situ tomography at PETRA III
- 2019
-
Ingår i: Developments in X-Ray Tomography XII. - : SPIE. - 0277-786X .- 1996-756X. - 9781510629196 ; 11113
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- A load frame for in situ mechanical testing is developed for the microtomography end stations at the imaging beamline P05 and the high-energy material science beamline P07 of PETRA III at DESY, both operated by the Helmholtz- Zentrum Geesthacht. The load frame is fully integrated into the beamline control system and can be controlled via a feedback loop. All relevant parameters (load, displacement, temperature, etc.) are continuously logged. It can be operated in compression or tensile mode applying forces of up to 1 kN and is compatible with all contrast modalities available at IBL and HEMS i.e. conventional attenuation contrast, propagation based phase contrast and differential phase contrast using a grating interferometer. The modularity and flexibility of the load frame allows conducting a wide range of experiments. E.g. compression tests to understand the failure mechanisms in biodegradable implants in rat bone or to investigate the mechanics and kinematics of the tessellated cartilage skeleton of sharks and rays, or tensile tests to illuminate the structure-property relationship in poplar tension wood or to visualize the 3D deformation of the tendonbone insertion. We present recent results from the experiments described including machine-learning driven volume segmentation and digital volume correlation of load tomography sequences.
|
|
| 3. |
|
|
| 4. |
- Sadowski, Eva-Maria, et al.
(författare)
-
Synchrotron X-rayimaging of a dichasium cupule of Castanopsis from Eocene Baltic amber
- 2018
-
Ingår i: American Journal of Botany. - : John Wiley & Sons. - 0002-9122 .- 1537-2197. ; 105, s. 2015-2036
-
Tidskriftsartikel (refereegranskat)abstract
- The partial female inflorescence reported here provides an important addition to acorns of Castanopsis described from middle Eocene strata of Europe. Furthermore, the intercontinental distribution of Castanopsis in the Eocene is confirmed. The amber fossil also broadens the picture of the Baltic amber source area, indicating oligotrophic, sandy, bog-like habitats. Finally, this study underscores the great benefit of SRμCT as a powerful tool to investigate plant inclusions from amber in a nondestructive way.
|
|
| 5. |
- Willumeit-Römer, Regine, et al.
(författare)
-
Visualization of Implant Failure by Synchrotron Tomography
- 2018
-
Ingår i: TMS 2018 147th Annual Meeting & Exhibition Supplemental Proceedings. - Cham : Springer. - 9783319725253 - 9783319725260 ; , s. 275-284
-
Konferensbidrag (refereegranskat)abstract
- Magnesium (Mg) and its alloys degrade under physiological conditions. But how strong is the connection between the implant, the corrosion layer and the surrounding tissue, namely bone? Biomechanical tests like push-out tests have shown that a degraded Mg-pin is surprisingly well integrated with the bone “as reported by Castellani et al. (Acta Biomater 7(1):432–440, 2011) [1]”. High-resolution synchrotron tomography offers a deep look into the microstructure of the material as well as of the bone during deformation until fracture happens. Here we present first data from an in situ tomography experiment of a biodegradable Mg-based implant under compressive load showing how Mg implants are incorporated into bone.
|
|
