An investigation of gender, perceived gender-barriers to a future occupation, and academic achievement among delinquent adolescents

The current study assesses perceptions of gender-related barriers to a future occupation and its association with academic achievement among delinquent adolescents aged 12-19 years old. It was hypothesized that the perception of gender related barriers to a future occupation would have similar effects on male and female adolescents\u27 academic achievement. Data included self-reported perceived barriers to a future occupation and academic achievement. Results indicated that females and males reported similar amounts of perceived barriers to a future occupation. Regression analysis indicated the relationship between perceived barriers and academic achievement varied across gender. For males, more perceived gender-barriers were associated with lower academic achievement, whereas, for females gender-barriers did not predict academic achievement. Although our hypothesis was not supported, the findings reveal an interesting phenomenon provoking the need for further study of gender, perceived barriers, and academic outcomes in delinquent populations

3D printed measurement phantoms for evaluation of magnetic particle imaging scanner

To assess the potential and capability of different MPI scanner designs and architectures, defined reference phantoms for imaging studies are required. For the preparation of well-defined structures as well as realistic vessel structures, 3D printed molds were filled with magnetic nanoparticles embedded into a long term stable polymeric matrix or perfused with a flowing ferrofluid. Different types and layouts of 3D printed phantoms will be presented which were imaged by means of MPI successfully

Evaluation of spatio-temporal resolution of MPI scanners with a dynamic bolus phantom

Magnetic particle imaging (MPI) is a tomographic imaging method to determine the spatial distribution of magnetic nanoparticles (MNP) within a defined volume. To evaluate the spatio-temporal resolution of existing MPI scanners, we developed dynamic MPI measurement phantoms. These segmented flow phantoms consist of a bolus of ferrofluid tracer material, pumped through a tube system. Using a hydrophobic organic carrier oil, cylindrically shaped bolus of different diameter, length, MNP concentrations, and flow velocity can be emulated. Moving boluses were imaged by MPI and the correlation of spatial resolution und velocity of the bolus was investigated. For all bolus dimension and flow velocity combinations, a decreasing spatial resolution and increasing blurring with increasing bolus velocity and decreasing bolus volume was observed

Vascular MPI: visualization and tracking of rapidly moving samples

Magnetic Particle Imaging (MPI) is a fast imaging technique for the visualization of the distribution of superparamagnetic iron-oxide nanoparticles (SPIONs) in 3D. For spatial encoding, a field free area is moved rapidly through the field of view (FOV) generating a localized signal. Fast moving samples, e.g., a bolus of SPIONs traveling through the large veins in the human body carried by blood flow with velocities in the order of ~45 cm/s and higher, cause temporal blurring in MPI measurements using common sequences and reconstruction techniques. This hampers the evaluation of dynamics of rapidly moving samples. In this abstract, initial results of rapidly moving samples in form of SPION boluses visualized within an MPI scanner are shown

Hemocompatibility testing according to ISO 10993-4 : Discrimination between pyrogen- and device-induced hemostatic activation

Next to good hemocompatibility performance of new medical devices, which has to be tested according to the ISO 10993-4, the detection of pyrogen-contaminated devices plays a pivotal role for safe device application. During blood contact with pyrogen-contaminated devices, intense inflammatory and hemostatic reactions are feared. The aim of our study was to investigate the influence of pyrogenic contaminations on stents according to the ISO 10993-4. The pyrogens of different origins like lipopolysaccharides (LPS), purified lipoteichoic acid (LTA) or zymosan were used. These pyrogens were dried on stents or dissolved and circulated in a Chandler-loop model for 90 min at 37 degrees C with human blood. Before and after circulation, parameters of the hemostatic system including coagulation, platelets, complement and leukocyte activation were investigated. The complement system was activated by LPS isolated from Klebsiella pneumoniae and Pseudomonas aeruginosa and by LTA. Leukocyte activation was triggered by LPS isolated from K. pneumoniae, LTA and zymosan, whereas coagulation and platelet activation were only slightly influenced. Our data indicate that pyrogen-contaminated devices lead to an alteration in the hemostatic response when compared to depyrogenized devices. Therefore, pyrogenicity testing should be performed prior to hemocompatibility tests according to ISO 10993-4 in order to exclude hemostatic activation induced by pyrogen contaminations. (C) 2014 Elsevier B.V. All rights reserved

Highly sensitive pyrogen detection on medical devices by the monocyte activation test

Pyrogens are components of microorganisms, like bacteria, viruses or fungi, which can induce a complex inflammatory response in the human body. Pyrogen contamination on medical devices prior operation is still critical and associated with severe complications for the patients. The aim of our study was to develop a reliable test, which allows detection of pyrogen contamination on the surface of medical devices. After in vitro pyrogen contamination of different medical devices and incubation in a rotation model, the human whole blood monocyte activation test (MAT), which is based on an IL-1β-specific ELISA, was employed. Our results show that when combining a modified MAT protocol and a dynamic incubation system, even smallest amounts of pyrogens can be directly detected on the surface of medical devices. Therefore, screening of medical devices prior clinical application using our novel assay, has the potential to significantly reduce complications associated with pyrogen-contaminated medical devices