Papers by Keyword: 3D-Microscopy

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Authors: Michele Curioni, Andronikos C. Balaskas, Teruo Hashimoto, Adewale I. Egbeolu, George E. Thompson
Abstract: In this work, an overview of recent developments in materials characterization and performance assessment methods applied to corrosion is given. It is shown that 3D techniques represent a powerful tool to gain fundamental information on the relationship between alloy microstructure and corrosion initiation and propagation. Subsequently, taking as an example an aluminium alloy anodized at two different potentials, the use of image assisted electrochemical noise analysis for the assessment of the practical performance of protective treatments is illustrated.
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Authors: Mario Helmis, Mont Kumpugdee-Vollrath
Abstract: For the development of colon delivery systems (CDS) formulations have to be gastric resistant. The advantage of the CDS is the ability for a local treatment for colon diseases but also its systemic action. CDS can also increase the bioavailability of poorly water soluble drugs e.g. resveratrol, which can be degraded in the upper gastrointestinal tract or by the First-Pass-Effect. In this project the coating technique with different polymer mixtures containing Kollicoat MAE-30DP, Eudragit-NM, Eudragit-L, and Eudragit-NE was investigated. Resveratrol was used as a model drug and all formulations were coated with a polymer mixture in a small scale fluidized bed apparatus. Morphology, roughness and film thickness of the coated tablets were determined by a scanning electron microscope and a 3D light microscope. Drug amount was determined by UV-spectrometry. Release studies were performed in a dissolution apparatus type II. Kinetic profiles of drug release were demonstrated. Results exhibit the advantages of polymer mixtures for CDS in comparison with results of pure Kollicoat MAE-30DP which were published in one of our latest publications.
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Authors: Catalin Cirstoiu, Razvan Ene, Mihai Nica, Patricia Ene, Monica Cîrstoiu
Abstract: The study presented in this paper was conducted to assess the main causes of osteosynthesis implants failure, among which implant material defects and unstable osteosynthesis fixation occur. A total number of 42 patients with osteosynthesis implant failure were included in this study in the Orthopedics and Traumatology Clinic of Bucharest Emergency University Hospital. The osteosynthesis implants failure was determined using radiological examination, only the patients with the age between 18 and 60 were selected. From the total number of patient included in our study, 18 had osteosynthesis performed with open reduction and plates and screws fixation, 5 intramedullary implants with open reduction, 4 intramedullary implants with close reduction, 15 cases of fixation with locking screws. For evaluating the macroscopic and microstructural features of the failure, we use microscopically techniques like stereomicroscopy, optical microscopy and scanning electron microscopy (SEM) techniques in conjunction with radiological images. After our analysis, in 14 cases we found a correct fixation but the microscopic examination of the implant materials reveals cracks in their structure, 24 cases showed an imperfect reduction of the fracture with interfragmentary diastasis and malrotation, and 4 had inadequate size devices, where the examination of failed metallic implants revealed no structural defects in implant materials. The results of our study showed that both design errors and inappropriate surgical procedures were causes of osteosynthesis failure. Therefore, special attention should be paid to the surgical fixation procedure but also to the fixation implant materials used.
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Authors: J.J.L. Mulders, A.P. Day
Abstract: Three-dimensional (3D) microscopy is a new and rapidly expanding area. A DualBeam system, with both a focused ion beam (FIB) column and an electron column, is a powerful instrument for imaging and sectioning microstructures to generate a full 3D sample reconstruction. When an electron backscatter diffraction (EBSD) system is attached to the DualBeam, it becomes a unique tool for making 3D crystallographic measurements on a wide variety of materials. Combining the successive removal by FIB, with sequential EBSD maps taken with the electron beam requires clear geometric considerations and a high level of automation to obtain a decent resolution in the third dimension, including positional sub-pixel re-alignment. Complete automation allows controlled sectioning and analysis of a significant volume of material without operator intervention: a process that may run continuously and automatically for many hours. Using a Nova600, a Channel 6 EBSD system and dedicated control software, Aluminium, Nickel and Steel specimens have been examined and volumes with up to 200 slices have been successfully analysed.
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