Institut fuer Materialforschung. Ergebnisbericht ueber Forschung und Entwicklung 1994

The IMF consists of three institutes with different tasks: IMF I works mainly on the development of metals, nonmetals and composite materials and on problems concerning the structure and properties of interfaces and protective layers. IMF II works on component reliablility, failure mechanisms and damage analysis. IMF III works on problems of process engineering in the production of ceramic powders and ceramic, metallic and polymeric microstructures, as well as on the design of nuclear components and the optimisation of corrosive materials. The IMF supports the research activities of Karlsruhe Research Center, especially in nuclear fusion research, microsystems engineering, nuclear safety, superconductivity, and low-pollution and low-waste processes. Materials and strength problems are investigated for future fusion reactors, high-performance microsystems, and safety problems in nuclear engineering. (orig./MM)Das Institut besteht aus den drei Teilinstituten IMF I, IMF II und IMF III. Die Aufgabengebiete gliedern sich in Angewandte Werkstoffphysik (IMF I), Werkstoff- und Strukturmechanik (IMF II) und Werkstoff-Prozesstechnik (IMF III). Das IMF I arbeitet hierbei bevorzugt an der Entwicklung von metallischen, nichtmetallischen und Verbundwerkstoffen sowie an Fragen zu Struktur und Eigenschaften von Grenzflaechen und Oberflaechenschutzschichten. Das IMF II behandelt schwerpunktmaessig die Zuverlaessigkeit von Komponenten, Versagenmechanik und Schadenskunde. Das IMF III bearbeitet prozesstechnische Fragestellungen bei der Herstellung keramischer Pulver und keramischer, metallischer und polymerer Mikrostrukturen. Daneben befasst es sich mit der Auslegung kerntechnischer Komponenten und der Optimierung korrosionsbelasteter Materialien. An den verschiedenen Arbeitsschwerpunkten des Kernforschungszentrums wirkt das Institut mit seinen Forschungsarbeiten besonders in der Kernfusion, Mikrosystemtechnik, Nuklearen Sicherheitsforschung, der Supraleitung sowie bei den schadstoff- und abfallarmen Verfahren mit. Es werden Material- und Festigkeitsprobleme fuer zukuenftige Fusionsreaktoren, in hochleistungsfaehigen Mikrosystemen und sicherheitsrelevante Fragen der Kerntechnik untersucht. (orig./MM)Available from TIB Hannover: ZA 5141(5534) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman

Ultrasonographic anatomy of abdominal lymph nodes in the normal cat

Lymph nodes are essential structures to be evaluated in an ultrasonographic examination of the feline abdomen. It was hypothesized that current technical proficiency would allow all feline abdominal lymph nodes to be identified ultrasonographically. Ten clinically normal, adult, domestic shorthair cats were examined using real-time compound ultrasonographic imaging. The medial iliac lymph nodes were visible in 100% of the cats, the jejunal lymph nodes in 90%, the hepatic lymph nodes in 70%, the aortic lumbar, the splenic, and the pancreaticoduodenal lymph nodes in 60% each, the ileocecal and the colic lymph nodes in 50% each, and the renal, the gastric, the sacral and the caudal mesenteric lymph nodes in 40%, 30%, 20%, and 10% of the cats, respectively. The inconsistent presence of lymph nodes, their poor echocontrast and interposed gas of the gastrointestinal tract explain the lower percentages of identification. The ultrasonographic length and diameter of the lymph nodes were determined. The majority of these measurements corresponded to those in the literature. We conclude that ultrasonography is a valuable tool for the identification and evaluation of most abdominal lymph nodes in the normal cat. Average ultrasonographic measurements are presented as a preliminary guideline for normal feline abdominal lymph nodes

Ex vivo MRI cell tracking of autologous mesenchymal stromal cells in an ovine osteochondral defect model

Abstract Background Osteochondral injuries represent a significant clinical problem requiring novel cell-based therapies to restore function of the damaged joint with the use of mesenchymal stromal cells (MSCs) leading research efforts. Pre-clinical studies are fundamental in translating such therapies; however, technologies to minimally invasively assess in vivo cell fate are currently limited. We investigate the potential of a MRI- (magnetic resonance imaging) and superparamagnetic iron oxide nanoparticle (SPION)-based technique to monitor cellular bio-distribution in an ovine osteochondral model of acute and chronic injuries. Methods MSCs were isolated, expanded and labelled with Nanomag, a 250-nm SPION, and using a novel cell-penetrating technique, glycosaminoglycan-binding enhanced transduction (GET). MRI visibility thresholds, cellular toxicity and differentiation potential post-labelling were assessed in vitro. A single osteochondral defect was created in the medial femoral condyle in the left knee joint of each sheep with the contralateral joint serving as the control. Cells, either GET-Nanomag labelled or unlabelled, were delivered 1 week or 4.5 weeks later. Sheep were sacrificed 7 days post implantation and immediately MR imaged using a 0.2-T MRI scanner and validated on a 3-T MRI scanner prior to histological evaluation. Results MRI data demonstrated a significant increase in MRI contrast as a result of GET-Nanomag labelling whilst cell viability, proliferation and differentiation capabilities were not affected. MRI results revealed evidence of implanted cells within the synovial joint of the injured leg of the chronic model only with no signs of cell localisation to the defect site in either model. This was validated histologically determining the location of implanted cells in the synovium. Evidence of engulfment of Nanomag-labelled cells by leukocytes is observed in the injured legs of the chronic model only. Finally, serum c-reactive protein (CRP) levels were measured by ELISA with no obvious increase in CRP levels observed as a result of P21-8R:Nanomag delivery. Conclusion This study has the potential to be a powerful translational tool with great implications in the clinical translation of stem cell-based therapies. Further, we have demonstrated the ability to obtain information linked to key biological events occurring post implantation, essential in designing therapies and selecting pre-clinical models